Nitric oxide in cancer and chemoprevention1

Free Radical Biology & Medicine, Vol. 34, No. 8, pp. 955–968, 2003 Published by Elsevier Inc. Printed in the USA. All rights reserved 0891-5849/03/$–see front matter

doi:10.1016/S0891-5849(02)01363-1

Serial Review; Nitric Oxide in Cancer Biology and Treatment Guest Editors: David A. Wink and James B. Mitchell NITRIC OXIDE IN CANCER AND CHEMOPREVENTION LORNE J. HOFSETH,* S. PERWEZ HUSSAIN,* GERALD N. WOGAN,†

and

CURTIS C. HARRIS*

*Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA; and † Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA (Received 25 July 2002; Revised 30 September 2002; Accepted 2 October 2002)

Abstract—Nitric oxide (NO) is a key molecule involved in many physiological functions. However, evidence is accumulating that sustained high levels of NO over extended periods of time contribute to carcinogenesis. This article reviews recent data and outlines a dual role of NO in animal carcinogenesis. Following an inhibition of NO production, some studies find a protection, while others find an exacerbation of tumorigenesis. These studies reflect the importance of (i) choosing the appropriate compound for NO inhibition; and (ii) genetic background, target tissue, levels of NO, and surrounding free radicals in the overall affects of NO on the tumor growth. These findings highlight the importance of further study of the use of NO inhibitors to inhibit human carcinogenesis. Published by Elsevier Inc.

INTRODUCTION

pathological conditions leads to production of high concentrations of NO (generally micromolar), which may be sustained for a long period. The human iNOS gene was first cloned in 1993 [23– 25] and has high homology among animal species. For example, the overall nucleotide sequence identity between murine and human iNOS cDNA is 80% [23]. The iNOS gene is approximately 37 kb in length and is located on chromosome 17cen-q11.2 [26,27]. The gene product contains 1203 amino acids (131 kD). iNOS was first shown to be induced in response to lipopolysaccharide (LPS) [28], but has since been shown to be under transcriptional control of several agents involved in the inflammatory process (e.g., cytokines [28 – 30]), microbial products (e.g., lipopolysaccharide [31]), and viral proteins (e.g., HBx [32,33]). In addition to transcriptional regulation of iNOS, NOS proteins can also be posttranslationally regulated by phosphorylation, dimerization, protein-protein interactions, subcellular localization, substrate availability, and cofactor binding [34 –39]. Although iNOS is easily induced and expressed in macrophages during host-defense mechanisms, many other cell types (including endothelial and epithelial cells) have also been shown to express iNOS (reviewed in [40]). An increased level of constitutive and inducible NOS expression and/or activity is also observed in a variety of human cancers [41– 49]. Moreover, iNOS ex-

Nitric oxide (NO), first described as endothelium-derived relaxation factor (EDRF) in the 1980s, is a key signaling molecule that mediates many physiological processes, including vasodilation, neurotransmission, host-defense, platelet aggregation, and iron metabolism [1–13]. However, accumulating evidence suggests that chronically elevated levels of NO produced during chronic inflammation contribute to a variety of pathological disorders, including cancer [14 –19]. NO is endogenously formed by a family of enzymes called NO synthases (NOS) [20]. There are three isoforms, two of which are Ca⫹2-dependent (NOS1 [neuronal NOS] and NOS3 [endothelial NOS]), and for the most part, constitutively expressed, while the Ca⫹2-independent isoform (NOS2 or iNOS) usually requires induction. Generally, Ca⫹2-dependent neuronal NOS1 and NOS3 produce low, sustained levels of NO ranging from pico to nanomolar concentrations. In contrast, iNOS generates bursts of NO concentrations several logs higher [21,22]. Continual activation of iNOS under some This article is part of a series of reviews on “Nitric Oxide in Cancer Biology and Treatment.” The full list of papers may be found on the homepage of the journal. Address correspondence to: Curtis C. Harris, M.D., Chief, Laboratory of Human Carcinogenesis, Bldg. 37 Rm 2C05, 37 Convent Drive, MSC 4255, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA; Tel: (301) 496-2048; Fax: (301) 496-0497; E-Mail: [email protected]. 955

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L. J. HOFSETH et al. Table 1. Oxyradical Overload Diseases, iNOS Expression, and Human Cancer Tissue iNOS Levels

Disease Inherited Hemochromatosis Wilson’s Disease Crohn’s Disease Ulcerative Colitis Acquired Viral Hepatitis B Hepatitis C Papillomavirus Bacterial Helicobacter pylori Bladder Catheterization‡ Cholecystitis‡ Parasitic S. hematobium S. japonicum Liver Fluke/Opisthorchis viverrini Chemical/Physical Barrett’s Esophagus/Acid Reflux Asbestos Smoking

Preneoplastic

Neoplastic

Cancer Site

Relative Risk

1 1 1 1

No Change * * *

Liver Liver Colon Colon

219

[60,61,189]

†

†

3.4 5.7

[51,52,190–193] [51,52,114,191–195]

1 1 *

1 1 *

Liver Liver Cervix

88 30 15.6

[57,196,197] [57,196–198] [199]

1 1 1

* * 1

Gastric Urinary Bladder Gall Bladder

10.4 4.7–28

[55,200,201] [202] [203,204]

No Change * 1

1 * *

Urinary Bladder Colon Liver (Cholangiocarcinoma)

2–14 1.2–5.7 14.1

[205,206] [205] [207,208]

1 * *

1 1 1

Esophageal Mesothelioma Lung

50–100 8.1 4.3¶

[62,209] [210,211] [212,213]

§

Reference

* Indicates unknown, or evidence is not clear from the literature; † Indicates specific relative risk has not clearly been shown in the literature because of early death from complications other than primary hepatocellular carcinoma; ‡ Indicates other physical irritations such as that from the catheter (for bladder catheterization) or gallstones (for cholecystitis) are likely to play a role in the genesis of cancer; § Indicates the study has not been done; ¶ Indicates if smoked equivalent to 20 cigarettes/d for 20 years.

pression and/or nitrotyrosine accumulation, in the mucosa of patients with cancer-prone chronic inflammatory diseases [(including ulcerative colitis (UC) [50 –52], Helicobacter pylori-associated gastritis [53–55], viral hepatitis [56 –59], Wilson’s Disease (WD) [60], hemochromatosis (HC) [60,61], and Barrett’s esophagus [62]] indicate that NO production and peroxynitrite formation may be involved in the pathogenesis of these diseases (Table 1). IS NO PROTECTIVE OR DESTRUCTIVE?

The induction of iNOS and subsequent biological actions of NO are complex. This complexity is highlighted by otherwise straightforward in vitro experiments using similar conditions, but showing contradicting results. The net effect of NO depends on its available concentration, target cell type, and interactions with reactive oxygen species (ROS), metal ions, and proteins (Fig. 1). Because of this environmental influence on NO actions, then, some studies show NO and associated chemical species damage DNA [63,64], others show NO as a protector from cytotoxicity associated with oxyradicals [65]. Also, in one cell type (umbilical vein endothelial cells) a specific NO donor (SNAP) inhibits cell proliferation [66], while in another cell type (mouse clonal osteogenic cells) SNAP stimulates cell prolifera-

tion [67]. The importance of NO concentration is demonstrated by the observation that SNAP stimulates proliferation at low concentrations (1–10 ␮M), but inhibits proliferation of the same cells at higher concentrations (50 ␮M) [68]. These complicated results extend to animal models. For example, iNOS knock-out mice show both exacerbated [69] and reduced [70] signs and symptoms of chemically or genetically-induced colitis (Tables 2 and 3). A possible explanation for the inhibitory effects on inflammation is that NO can reduce the expression and function of proinflammatory chemokines [71], adhesion molecules [72,73], cyclooxygenase 2 (COX2 [74]), cytokines [73,75], and matrix metalloproteins [76]. To add to the complexity, depending on its level and cell type, NO can act in a negative or positive feedback loop to block or activate its key inducer, NF-␬B, and therefore, the transcription of target genes [77– 80]. Implications in the possible use of iNOS and NO regulators for chemoprevention will be discussed. Recent studies have described NO involvement in several biological processes affecting carcinogenesis. These include initiation (irreversible genetic damage occurring in central cancer control genes), promotion, progression, metastasis, and tumor microcirculation and angiogenesis. These subjects have been reviewed in detail elsewhere [40,81– 87].

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Fig. 1. Differential effects of nitric oxide on tumorigenesis.

In the course of defense against pathogenic organisms, NO species from activated macrophages can act on otherwise healthy neighboring epithelial cells, damaging their DNA and driving carcinogenesis. It is also clear that as an endothelial growth factor, NO mediates tumor vascularization [88,89] and tumor blood-flow [90]. Although high concentrations of NO induce apoptosis in susceptible cells [91], low concentrations can be antiapoptotic [92]. For example, both exogenously and endogenously produced NO reduce the frequency of apoptosis by inhibiting caspases in cultured hepatocytes [93]. The mechanisms of NO-induced apoptosis (detailed by Billiar and coworkers in this issue) are complex and again are dependent on the concentrations of NO, celltype, redox state, and the level of metal-ion complex within the cell [94,95]. Because cytokines and hypoxia synergistically induce iNOS expression in stromal macrophages [96], the microenvironmental changes in premalignant and malignant tumor tissue may establish sustained and high NO production, thereby supporting clonal selection of preneoplastic cells and tumor growth. High levels of NO may modify DNA directly [64,97,98] or inhibit DNA-repair activities [99] such as

human thymine-DNA glycosylases that repair G:T mismatches at CpG sites [100] (Fig. 1). Because NO overproduction induces accumulation and posttranslational modification of p53 [101–103], the resulting growth inhibition provides additional selection pressures for clonal expansion of cells with mutant p53 (Fig. 1). This hypothesis is supported by experiments with human cancer cell lines that were genetically engineered to produce NO in amounts comparable to those generated in human cancer. Cancer cells with wild-type p53 and iNOS expression showed increased induction of the G1-S cell cycle checkpoint protein, p21waf1, and reduced tumor growth and increased tumor necrosis as xenografts in athymic nude mice. However, those with mutated p53 had accelerated tumor growth associated with increased vascular endothelial growth factor (VEGF) expression and neovascularization [104]. Other investigators have confirmed that NO regulates VEGF [88,105–107]. These data indicate that tumor-associated NO production may promote cancer progression by providing both a selective growth advantage to tumor cells with mutant p53 and an angiogenic stimulus. One interesting line of evidence suggests NO activates the transcription factor hypoxia-inducible

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L. J. HOFSETH et al. Table 2. Animal Studies Showing Inhibition of Inflammation and Tumorigenesis by iNOS Ablation or Inhibitors

Treatment

Regimen

Experimental Model

iNOS KO

1 mg, anally

Trinitrobenzene-treated mice

iNOS KO

N/A

Aminoguanidine Aminoguanidine Aminoguanidine Aminoguanidine Aminoguanidine

10 mg/kg, i.p. 20 mg/kg, s.c. 1 g/l in drinking water 1800 ppm, in food 1.5 ␮mole/kg/day, orally

B16-BL6 and ⫺F10 melanoma cells injected into iNOS mice Concanavalin-treated mice Serotonin-treated rats APC(Min/⫹) mice AOM-treated mice Trinitrobenzene-treated rats

Aminoguanidine

10 mg/kg, i.p.

Trinitrobenzene-treated rats

NMA

30 mM, in drinking water

SJL mice

L-NAME

1 g/l, in drinking water

L-NNA

3 mg/kg, i.v.

L-NAME L-NAME

2 mM, in drinking water 0.1 g/day, in drinking water

Transplanted rat P22 carcinosarcoma cells into flank of rats Transplanted rate P22 carcinosarcoma cells into flank of rats A-431 explants onto rabbit cornea Rabbit cornea assay

L-NAME L-NAME

0.1–1 mg/ml, in drinking water 80 mg/kg, i.p.

L-NAME

10 mg/kg, i.v.

L-NAME L-NAME

2 mg, i.p. 2 mM, osmotic minipumps

L-NAME L-NAME

100 ppm, in food 50 mg/kg

Smethylisothiourea Sulphate SC-51 PBIT 1400W 1400W 1400W

Transplanted C3-L5 mammary cancer cells Renal subcapsular CC531 adenocarcinoma rat model or isolated limb perfusion model Implanted murine mammary and human colon cells subcutaneously into mice Breast cancer cells injected into mice Murine breast cancer injected into mice AOM-treated mice Subcutaneous implant of hepatoma cells

0–100 ppm in food 50 ppm in food 2 mg/kg/day, i.p.

AOM-treated mice AOM-treated mice Trinitrobenzene-treated rats

12 mg/kg/h, continuous infustion 6 mg/kg/h, continuous infusion

EMT6 murine mammary adenocarcinoma Human tumor xenograft (DLD-1 cells ⫹ iNOS)

factor-1 alpha (HIF-1␣) [108 –110], which in turn targets VEGF and can promote angiogenesis [111]. As a protective mechanism against prolonged exposure to pathological levels of NO, wild-type p53 has been shown to trans-repress iNOS expression and NO production in vitro [102]. As predicted from these results, p53 knockout mice show increased basal and induced expression of iNOS [112]. These studies show that tissues undergoing chronic inflammation in the absence of wild-type p53 may be more susceptible to cancer development because of a lack of negative regulation of iNOS leading to increased NO production. NO generated by iNOS may mutate p53 during human carcinogenesis [113–115]. Recently, we have

Observed Effect

Reference

Decreased inflammation from 3–7 d Decreased metastases

[70]

Reduced hepatitis Reduced gastritis Reduced adenoma Reduced ACF Reduced damage, myeloperoxidase Activity and serum nitrogen oxide Reduced colonic damage and myeloperoxidase activity Reduce nitrate/nitrite, mutation frequency and etheno adducts Reduced tumor blood flow

[146] [147] [138] [148] [214]

Reduced tumor blood flow

[90,154]

Delayed angiogenic response Inhibited angiogenesis by the tachykinin, ‘Substance P’ Reduce tumor growth and metastases Reduced tumor growth

[122] [155]

[166,168]

[215] [142,144] [153]

[156] [216]

Reduced vessel diameter and blood flow

[217]

Reduced metastases Reduced tumor size and metastases Reduced ACF Reduced tumor growth

[164] [218]

Reduced ACF Reduced ACF Reduced damage score, iNOS activity and myeloperoxidase activity Reduced tumor weight

[148] [149] [219]

Reduced tumor growth

[152]

[150] [151]

[152]

shown iNOS expression is elevated and there are high p53 codon 247 and 248 mutation frequencies in inflamed lesional regions of the colon of patients with UC [114]. Tissues from patients with WD and HC also have high expression of iNOS along with G:C to T:A transversions at codon 249, C:G to A:T transversions and C:G to T:A transitions at codon 250 (WD) and higher frequencies of G:C to T:A transversions at codon 249 (HC) [60]. In spontaneous colon tumors, iNOS activity appears to be expressed throughout the tumorous colon and is highest in adenomas, then declines with an advancing tumor stage, and is lowest in metastatic tumors [113,116]. The decline in iNOS activity with advancing tumor stage may be attributed to fas-ligand-induced killing of tumor-as-

Cancer and chemoprevention

sociated mononuclear cells (TMC) in advanced tumors [117]. In colon tumors, p53 mutations are primarily in the evolutionarily conserved region of the gene, which contains about 85% of the p53 mutations and all of the mutational hotspots at CpG sites [118,119]. iNOS activity is positively correlated with G:C to A:T mutations at 5-methylcytosine sites in p53, but the rates of all other mutations vary inversely with iNOS activity [113]. Interestingly, G:C to A:T transition mutations are common in lymphoid, esophageal, head and neck, stomach, brain, and breast cancers [118 –120], four of which are known to display elevated iNOS expression [42,116,121,122]. Thus, evidence that NO and its derivatives mutate key cancer-related genes, that it provides a selection pressure for clonal expansion of mutated or aberrant cells, and that it promotes angiogenesis, indicates that NO can act as both an endogenous initiator and promoter in human carcinogenesis. TARGETING iNOS IN CHEMOPREVENTION

Strategies for preventing cancer in high risk populations such as those with chronic inflammation include vaccinations and/or eradication of the causative agent, gene therapy, behavioral changes, surveillance, screening, and prophylactic surgery. All approaches may be complemented by chemoprevention strategies that could significantly reduce the risk of cancer in high risk tissues. Populations in which inhibitors of iNOS have promise to reduce cancer risk include those with chronic inflammation. Chronic inflammation can provide a microenvironment that drives tumorigenesis (reviewed in [123–125]). Production of cytokines and the activation of inflammatory cells with the subsequent generation of ROS and nitrogen oxide species (RNOS) during chronic inflammation can alter a number of targets (DNA, proteins, and lipids) and pathways critical to normal tissue homeostasis (reviewed in [126]). Mutations in oncogenes and tumor suppressor genes or posttranslational modifications of proteins by ROS and RNOS are some of the key events that can increase the risk of developing cancer. In addition, oxidative/nitrosative stress can modulate cell growth and tumor promotion by activating signal transduction pathways, which results in the transcriptional induction of growth competence-related proto-oncogenes, chromatin remodeling, apoptosis, and cell cycle checkpoints [127–132]. As summarized in Table 1, a chronic inflammatory disease develops from conditions with chronic inflammation and can have an etiology that is: (i) inherited [e.g., HC, WD, Crohn’s disease (CD), UC], (ii) acquired through viral (e.g., hepatitis B or C virus and liver cancer, human papillomavirus and cervical cancer), bac-

959

terial (e.g., helicobactor pylorus and gastric cancer, longterm bladder catheterization and bladder cancer, cholecystitis and gall bladder cancer), and parasitic (e.g., S. hematobium and bladder cancer, S. japonicum and colon cancer, liver flukes/Opisthorchis viverrini and cholangiocarcinoma), or (iii) acquired through chemical induction (e.g., acid reflux in Barrett’s esophagus and esophageal cancer, asbestos and mesothelioma, smoking and lung cancer). Although the specific mechanisms are still unclear, cancer-proneness is frequently a pathological consequence of extensive oxidative and nitrosative stressrelated damage in these diseases. The diversity of reactive species produced during chronic inflammation under different cellular microenvironments have impaired identification of a clear biomarker that identifies the involvement of a single reactive species in the carcinogenic process. However, as summarized in Table 1, many of these diseases are associated with an increase in iNOS expression and nitrosative stress in precancerous tissue. Based on these observations, along with evidence from animal models, one can hypothesize that chronic overexpression of iNOS and associated NO production may contribute to tumorigenesis, and is therefore, an attractive target for chemoprevention. A suggestion to the effectiveness of targeting iNOS in chemoprevention comes from experiments in iNOS knockout mice, first generated in 1995 [133]. Some studies have shown extensive early phase inflammation in iNOS⫺/⫺ mice treated with trinitrobenzene sulphonic acid [69]. This is a well-established model of experimental colitis, which has an immunological component, and is known to develop into a chronic intestinal inflammation approximately 1 week after the induction of colitis. Others have found these mice to have a significant resistance to trinitrobenzene-induced lethality and colonic damage, and reduced nitrotyrosine formation and malondialdehyde concentrations [70]. When these mice are fed dextran sodium sulfate (DSS) they have reduced signs and symptoms of colitis compared with wild-type mice, indicating iNOS plays a critical role in the pathology of colitis [134,135]. The implications of this reduced inflammation on the development of colon cancer in these mice has not been shown. A study by Konopka et al. [136] describes fewer tumors and lower VEGF expression in iNOS⫺/⫺ mice injected with B16-F1 melanoma cells, indicating a role for iNOS in tumor progression. Cooper and colleagues found that mice with a germline adenomatous polyposis coli (APC) gene mutation (Minmice) fed DSS, develop significantly accelerated colitis, dysplasia, and cancer compared with wild-type mice, indicating this mutation may contribute to cancer associated with inflammatory bowel disease [137]. Finally, Ahn and Ohshima have shown a significant reduction in adenomas in Min/iNOS⫺/⫺ mice compared with Min

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L. J. HOFSETH et al.

mice alone [138], indicating that NO plays a key role in promoting colon carcinogenesis in a background of APC mutation. The implications of these findings to human cancers remain to be determined. One way to target iNOS for chemoprevention is through the targeting of the NF-␬B pathway, because this pathway is central to iNOS induction. The therapeutic potential of NF-␬B pathway inhibition in the treatment of inflammation and cancer has recently been reviewed by Yamamoto and Gaynor [139]. Briefly, this pathway is the target of many antiinflammatory drugs including degradation-resistant I␬B proteins, glucocorticoids, nonsteroidal antiinflammatory drugs (NSAIDs), immunosuppressive agents, cyclopentenone prostaglandins, proteosome inhibitors, and flavonoids (quercetin, resveratrol, and myricetin). Several laboratories have described that NF-␬B sites in the promoter region of iNOS are required for transcriptional activity. Therefore, it is not surprising to find that many drugs targeting NF-␬B also block iNOS gene expression and subsequent NO production. Although these drugs reduce inflammation, studies are needed to understand more fully their impact on carcinogenesis. Of the drugs that have been shown to reduce carcinogenesis, it is unclear whether the mechanism is through iNOS expression and NO production or whether this is just coincidental. The evidence pointing toward a critical role of iNOS and NO on inflammation and carcinogenesis has led to the development of drugs specifically targeting these molecules. We outlined above the effect of genetic ablation of iNOS on carcinogenesis in animals. Relatively few studies have examined the direct impact of iNOS inhibitors on carcinogenesis in animal models of human cancer, and no studies have been done in humans. Exogenous administration of xenobiotics and transgenic mouse models that have increased iNOS and NO production are models that have been used to examine NO effects on inflammation and tumorigenesis. For example, SJL mice injected with superantigen-bearing RcsX (pre-B-cell lymphoma) cells generate large amounts of NO with associated apoptosis, nitrotyrosine formation, etheno DNA adducts, mutagenesis, and tumor formation [140 – 142]. Although many other animal models of chronic inflammation show the induction of iNOS and NO generation and increased tumorigenesis [141,143–145], these models provide only indirect evidence that NO drives tumorigenesis. Further direct evidence comes from the administration of iNOS and NO inhibitors. For example, inhibition of NO synthesis has been shown in animal models to inhibit hepatitis [146] and gastritis [147]. Ahn and Ohshima [138] found the administration of the iNOS inhibitor aminoguanidine in drinking water or an L-arginine-deficient diet to APC (Min/⫹) mice resulted in a significant decrease in adenoma develop-

ment. Rao et al. [148] examined the impact of iNOS inhibitors alone or in combination with COX2 inhibitors on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF), a precursor of colonic cancer. They found a significant inhibition of ACF with the iNOS inhibitors, L-N(6)-(1-iminoethyl)lysine tetrazole-amide (SC-51) and aminoguanidine (AG), and an even greater reduction in the frequency of ACF with the co-administration of SC-51 and the COX2 inhibitor, celecoxib. This study is an extension of earlier studies showing an inhibition of AOM-induced ACF formation by the iNOS inhibitor PBIT [149]. Kawamori et al. [150] showed that 1-N(G)-nitroarginine methyl ester (LNAME) fed to rats inhibited AOM-induced ACF formation by 24 –39%. Doi et al. [151] described a moderate suppression of experimental solid tumor (AH136 hepatoma) cell growth in rats by L-NAME. Finally, Thomsen et al. [152] showed that the novel iNOS inhibitor, 1400W, significantly reduces tumor growth of EMT6 murine mammary adenocarcinomas and human tumor xenografts (colon adenocarcinoma DLD-1) genetically engineered to express iNOS constitutively. In this review, we described previously the impact of NO on VEGF and angiogenesis [88,104 –107]. To further evaluate this connection, Tozer et al. [153] showed that the co-administration of the tubulin destabilizing agent, disodium combretastatin A-4 3-0-phosphate (CA4-P) with N(omega)-nitro-L-arginine methyl ester, dramatically reduces the established tumor vasculature, leading to the development of extensive tumor cell necrosis. Similarly, the same group showed a reduction in tumor blood flow with the administration of N(omega)nitro-L-arginine (L-NNA) alone [90,154]. In independent studies, using a rabbit cornea assay, Ziche et al. [155], and then Gallo et al. [122] described an inhibition of NO-induced angiogenesis by blocking NO production. Similarly, L-NAME treatment reduces tumor growth in adenocarcinoma-bearing mice [156]. Finally, Jenkins and colleagues [88] showed an increase in vessel density and tumor growth in iNOS-transfected tumors. In contrast to the above studies, some have shown either no effect or even an exacerbation of inflammation and tumorigenesis by NO inhibition (Table 3). In a Rhesus monkey model, Ribbons and colleagues found no effect of L-N6-(1-imineothyl) (L-NIL) or aminoguanidine on spontaneous colitis [157]. Yoshida et al. [158] showed that inhibition of NO production by either LNAME or AG worsened DSS-induced inflammation, suggesting a protective role for NO in acute colitis. As described earlier, one explanation for this effect may be the observation that NO acts as a scavenger of ROS [159] and can inhibit induction of inflammation-associated genes [71–76]. Because NO donors can also exaggerate inflammation, we believe that inflammation can be ag-

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Table 3. Animal Studies Showing No Effect or Enhancement of Inflammation and Tumorigenesis by iNOS Ablation or Inhibitors Treatment

Regimen

Experimental Model

iNOS KO

6 mg, anally

Trinitrobenzene-treated mice

iNOS KO

N/A

iNOS KO

N/A

L-NIL

60 mg/kg/d, orally

Pancreatic cells implanted into pancreas of mice M5076 murine ovarian cells injected into mice Spontaneous monkey colitis

100 mg/kg/d, orally

L-NAME L-NAME L-NAME

400 mg/kg/d, orally 10 mg/kg, in drinking water 9.3 ␮mole, i.v. 500 mg/l, in drinking water

Aminoguanidine NMA

10 mg, injected twice daily

NMA

20 mg, injected twice daily

L-NMMA L-NNA

50 mg/kg, i.p. 10 mg/kg, i.p.

or Aminoguanidine L-NAME Aminoguanidine

Observed Effect

Reference

Transiently increased inflammation from 24–72 h Slight increase in liver metastases Increased metastases

[69]

No impact on colitis

[157]

DSS-induced rat colitis

Worsened DSS-induced inflammation

[158]

AOM-treated rats Experimental pulmonary metastases Trinitrobenzene-treated rats

Promotes colon ACF Promotes metastases No impact on colitis

[160] [163] [220]

M5076 i.v. injected into mice for liver metastases metastases iNOS transfected cells i.v. injected into mice Trinitrobenzene-treated rats Trinitrobenzene-treated rats

Inhibits antitumor effect of iNOS Inhibits antitumor effect of iNOS Increased colonic damage score Aggravated colonic damage and myeloperoxidase activity

[171]

gravated by either too much or too little NO. Medical treatment of inflammatory diseases should, therefore, aim for maintenance of “appropriate NO levels” in the target tissue. Due to the inherent heterogeneity of NO on normal and tumor cells, it is still unclear what levels are appropriate. Using cancer as an endpoint, Schleiffer and co-workers [160] showed that L-NAME enhances AOM-induced ACF formation by 47%. Others have shown that immunomodulators can reduce tumor growth and metastasis through an activation of iNOS expression in macrophages [161,162]. The observation of an inverse correlation between expression of endogenous iNOS and NO production and metastasis indicates that NO can reduce metastatic potential of tumors (reviewed in [87]). This inhibition of metastases by NO is supported with experiments by Yamamoto and colleagues, who show increased experimental pulmonary metastasis by L-NAME [163]. However, Iwasaki et al. show that the incidence and number of osteolytic bone metastases and the number of bones with metastasis is significantly reduced in L-NAME-treated mice [164]. Similarly, Edwards and colleagues described an augmentation of tumor growth and metastasis by NO in mice injected with EMT-6 murine breast cancer cells [165]. Insight into these contradicting results are presented by Xie and Fiedler’s groups through an elegant set of studies using iNOS ablation, iNOS inhibitors, iNOS induction, or NO donors. They suggest that the effect of NO on tumor growth and metastases depends on the levels of NO delivered (often high NO levels lead to cell killing and, therefore,

[167] [167,168]

[174] [221] [215]

tumor ablation), genetic background, and cell type (which determine the NO sensitivity [87,166 –175]). Most studies examining an impact of NO on angiogenesis have established an exacerbation of angiogenesis by NO (and a protective effect against angiogenesis by iNOS inhibitors). Although for the most part, studies have shown iNOS inhibitors reduce inflammation, tumor promotion, and metastases, some have found opposite results (i.e., inhibition of inflammation and tumorigenesis by NO). This apparent contradictory evidence in animals highlights the importance of careful scrutiny of the use of iNOS inhibitors as chemopreventive agents in humans. Studies now show a valuable link between the use of NO as an adjuvant therapy, as it appears to sensitize cells to the effects of chemotherapy [176 –178]. The putative cytotoxic effects of NO or its role in a negative feedback loop might also be exploited in the clinical setting to suppress the expression of genes involved in chronic inflammation, in addition to sending damaged cells into apoptosis. However, although NO clearly induces DNA damage and can drive tumorigenesis, the impact of directly inhibiting tumorigenesis with iNOS inhibitors needs further evaluation. One can hypothesize that the opposing roles of NO in tumorigenesis are a function of the complicated chemistry of NO as well as NO levels, the biologic phenotype and genetic make-up of the tumor cells, and the surrounding microenvironment (e.g., scavengers, hypoxia, pH, etc.). NO at high concentrations may damage cells extensively enough to initiate apoptosis. In contrast, because of their phenotype and genotype, some cells may resist NO-

962

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driven apoptosis, or there may be a relatively low amount of NO produced in certain areas that provides a microenvironment conducive to cell survival, clonal expansion, and tumorigenesis (possibly through an interactive role with COX2). The key role of genetic background is highlighted by the observation that the response of cells to NO depends largely on p53 status [104,179]. Because the frequency of adenomas are reduced in Min/iNOS⫺/⫺ mice compared with Min mice alone [138], NO can also promote carcinogenesis in the genetic background of APC mutation. These studies have allowed us to understand more fully, potential responses of tissue and tumors to NOtargeted treatments. It is clear that animal models have to be carefully chosen to properly evaluate the efficacy of iNOS inhibitors in chemoprevention and tumorigenesis. Additional studies are required to (i) identify molecules that are better at targeting iNOS, and (ii) identify the efficacy and mechanisms of current and future iNOS inhibitors in tumorigenesis/tumor protection and guide the use of these molecules as chemopreventive agents in humans. One way to monitor the use of these agents in chemoprevention trials is through the use of intermediate biomarkers. Ultimately, the most valid biomarkers are those that are (i) mechanistically involved in carcinogenesis (e.g., DNA damage, proliferation, differentiation, and apoptotic markers); (ii) properly predict cancer outcome; and (iii) can be measured in human tissue or surrogate biological fluids. Few promising markers fit into these categories. A recent review of many markers of internal dose (e.g., levels of reactive oxygen and nitrogen byproducts) and internal effect dose (e.g., levels of DNA or protein adducts/damage in target and/or surrogate tissue) and the use of these in chemoprevention trials is provided by Dr. Bartsch [180]. Some specific markers used in the monitoring of nitrosative stress and chemoprevention of this stress include: N-nitrosoproline (NPRO), N-nitrosamino acids (NAA; e.g., N-nitrosothiazolidine 4-carboxylic acid, N-nitroso-2-ethyl-thiazolide 4-carboxylic acid), and NO3⫺ in urine or plasma; 8-oxodeoxyguanosine (8-oxodGuo), 8-nitrosoguanosine (8nitroGua), exocyclic etheno- and malondialdehyde-DNA adducts in leukocytes or target tissue; and 3-nitrotyrosine protein adducts [180 –183]. The consequences of these effect markers on human carcinogenesis are unknown. More direct markers, therefore, are aimed at the identification of molecular changes in genes or proteins directly associated with carcinogenesis. One such marker is a highly sensitive genotypic assay developed by Cerutti and coworkers. This has allowed the detection of low-frequency mutations in normal-appearing human tissues as well as in cells exposed to an environmental carcinogen [184 –188]. As described earlier, we have recently used this technique to detect p53 mutations in

the target tissue of patients with the oxyradical overload diseases UC (colon), HC (liver), and WD (liver) [60,114]. Others have found that there are specific DNA profiles (hotspots) associated with NO exposure [97]. The identification of these hotspots, the detection of specific mutations in cancer-causing genes, or the use of microarrays to detect patterns of gene expression and/or protein changes in normal-appearing tissue may help identify individuals at increased cancer risk and help in the evaluation of iNOS and NO inhibitors in chemoprevention. Acknowledgements — We thank Ms. Dorothea Dudek for editorial assistance and the help of Mrs. Karen MacPherson for bibliographic assistance.

REFERENCES [1] Fleming, I.; Busse, R. NO: the primary EDRF. J. Mol. Cell. Cardiol. 31:5–14; 1999. [2] Ignarro, L. J. Physiology and pathophysiology of nitric oxide. Kidney Int. Suppl. 55:S2–S5; 1996. [3] Moncada, S.; Higgs, E. A. Molecular mechanisms and therapeutic strategies related to nitric oxide. FASEB J. 9:1319 –1330; 1995. [4] Furchgott, R. F. Introduction to EDRF research. J. Cardiovasc. Pharmacol. 22(Suppl. 7):S1–S2; 1993. [5] Moncada, S.; Palmer, R. M.; Higgs, E. A. Nitric oxide: physiology, pathophysiology, and pharmacology. Pharmacol. Rev. 43:109 –142; 1991. [6] Radomski, M. W.; Palmer, R. M.; Moncada, S. An L-arginine/ nitric oxide pathway present in human platelets regulates aggregation. Proc. Natl. Acad. Sci. USA 87:5193–5197; 1990. [7] Sanders, K. M.; Ward, S. M. Nitric oxide as a mediator of nonadrenergic noncholinergic neurotransmission. Am. J. Physiol. 262:G379 –G392; 1992. [8] Furchgott, R. F.; Jothianandan, D. Endothelium-dependent and -independent vasodilation involving cyclic GMP: relaxation induced by nitric oxide, carbon monoxide and light. Blood Vessels 28:52– 61; 1991. [9] Nathan, C.; Shiloh, M. U. Reactive oxygen and nitrogen intermediates in the relationship between mammalian hosts and microbial pathogens. Proc. Natl. Acad. Sci. USA 97:8841– 8848; 2000. [10] Cheung, P. Y.; Salas, E.; Etches, P. C.; Phillipos, E.; Schulz, R.; Radomski, M. W. Inhaled nitric oxide and inhibition of platelet aggregation in critically ill neonates. Lancet 351:1181–1182; 1998. [11] Salvemini, D.; de Nucci, G.; Gryglewski, R. J.; Vane, J. R. Human neutrophils and mononuclear cells inhibit platelet aggregation by releasing a nitric oxide-like factor. Proc. Natl. Acad. Sci. USA 86:6328 – 6332; 1989. [12] Pantopoulos, K.; Weiss, G.; Hentze, M. W. Nitric oxide and oxidative stress (H2O2) control mammalian iron metabolism by different pathways. Mol. Cell. Biol. 16:3781–3788; 1996. [13] Domachowske, J. B. The role of nitric oxide in the regulation of cellular iron metabolism. Biochem. Mol. Med. 60:1–7; 1997. [14] Moncada, S.; Palmer, R. M.; Higgs, E. A. Nitric oxide: physiology, pathophysiology, and pharmacology. Pharmacol. Rev. 43:109 –142; 1991. [15] Nathan, C.; Xie, Q. W. Nitric oxide synthases; roles, tolls, and controls. Cell 78:915–918; 1994. [16] Bredt, D. S.; Snyder, S. H. Nitric oxide: a physiologic messenger molecule. Annu. Rev. Biochem. 63:175–195; 1994. [17] Hentze, M. W.; Kuhn, L. C. Molecular control of vertebrate iron metabolism: mRNA-based regulatory circuits operated by iron,

Cancer and chemoprevention

[18]

[19]

[20] [21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

nitric oxide, and oxidative stress. Proc. Natl. Acad. Sci. USA 93:8175– 8182; 1996. Tamir, S.; Tannenbaum, S. R. The role of nitric oxide (NO) in the carcinogenic process. Biochim. Biophys. Acta 1288:F31– F36; 1996. Ambs, S.; Hussain, S. P.; Harris, C. C. Interactive effects of nitric oxide and the p53 tumor suppressor gene in carcinogenesis and tumor progression. FASEB J. 11:443– 448; 1997. Marletta, M. A. Nitric oxide synthase: aspects concerning structure and catalysis. Cell 78:927–930; 1994. Beckman, J. S.; Beckman, T. W.; Chen, J.; Marshall, P. A.; Freeman, B. A. Apparent hydroxyl radical production by peroxynitrite: implications for endothelial injury from nitric oxide and superoxide. Proc. Natl. Acad. Sci. USA 87:1620 –1624; 1990. Malinski, T.; Taha, Z.; Grunfeld, S.; Patton, S.; Kapturczak, M.; Tomboulian, P. Diffusion of nitric oxide in the aorta wall monitored in situ by porphyrinic microsensors. Biochem. Biophys. Res. Commun. 193:1076 –1082; 1993. Geller, D. A.; Lowenstein, C. J.; Shapiro, R. A.; Nussler, A. K.; Di Silvio, M.; Wang, S. C.; Nakayama, D. K.; Simmons, R. L.; Snyder, S. H.; Billiar, T. R. Molecular cloning and expression of inducible nitric oxide synthase from human hepatocytes. Proc. Natl. Acad. Sci. USA 90:3491–3495; 1993. Sherman, P. A.; Laubach, V. E.; Reep, B. R.; Wood, E. R. Purification and cDNA sequence of an inducible nitric oxide synthase from a human tumor cell line. Biochemistry 32:11600 – 11605; 1993. Charles, I. G.; Palmer, R. M.; Hickery, M. S.; Bayliss, M. T.; Chubb, A. P.; Hall, V. S.; Moss, D. W.; Moncada, S. Cloning, characterization, and expression of a cDNA encoding an inducible nitric oxide synthase from the human chondrocyte. Proc. Natl. Acad. Sci. USA 90:11419 –11423; 1993. Chartrain, N. A.; Geller, D. A.; Koty, P. P.; Sitrin, N. F.; Nussler, A. K.; Hoffman, E. P.; Billiar, T. R.; Hutchinson, N. I.; Mudgett, J. S. Molecular cloning, structure, and chromosomal localization of the human inducible nitric oxide synthase gene. J. Biol. Chem. 269:6765– 6772; 1994. Marsden, P. A.; Schappert, K. T.; Chen, H. S.; Flowers, M.; Sundell, C. L.; Wilcox, J. N.; Lamas, S.; Michel, T. Molecular cloning and characterization of human endothelial nitric oxide synthase. FEBS Lett. 307:287–293; 1992. Stuehr, D. J.; Cho, H. J.; Kwon, N. S.; Weise, M. F.; Nathan, C. F. Purification and characterization of the cytokine-induced macrophage nitric oxide synthase: an FAD- and FMN-containing flavoprotein. Proc. Natl. Acad. Sci. USA 88:7773–7777; 1991. Markewitz, B. A.; Michael, J. R.; Kohan, D. E. Cytokineinduced expression of a nitric oxide synthase in rat renal tubule cells. J. Clin. Invest. 91:2138 –2143; 1993. Koide, M.; Kawahara, Y.; Tsuda, T.; Yokoyama, M. Cytokineinduced expression of an inducible type of nitric oxide synthase gene in cultured vascular smooth muscle cells. FEBS Lett. 318: 213–217; 1993. Lowenstein, C. J.; Alley, E. W.; Raval, P.; Snowman, A. M.; Snyder, S. H.; Russell, S. W.; Murphy, W. J. Macrophage nitric oxide synthase gene: two upstream regions mediate induction by interferon gamma and lipopolysaccharide. Proc. Natl. Acad. Sci. USA 90:9730 –9734; 1993. Amaro, M. J.; Bartolome, J.; Carreno, V. Hepatitis B virus X protein transactivates the inducible nitric oxide synthase promoter. Hepatology 29:915–923; 1999. Elmore, L. W.; Hancock, A. R.; Chang, S. F.; Wang, X. W.; Chang, S.; Callahan, C. P.; Geller, D. A.; Will, H.; Harris, C. C. Hepatitis B virus X protein and p53 tumor suppressor interactions in the modulation of apoptosis. Proc. Natl. Acad. Sci. USA 94:14707–14712; 1997. Dimmeler, S.; Fleming, I.; Fisslthaler, B.; Hermann, C.; Busse, R.; Zeiher, A. M. Activation of nitric oxide synthase in endothelial cells by Akt-dependent phosphorylation. Nature 399: 601– 605; 1999.

963

[35] Pan, J.; Burgher, K. L.; Szczepanik, A. M.; Ringheim, G. E. Tyrosine phosphorylation of inducible nitric oxide synthase: implications for potential post-translational regulation. Biochem. J. 314:889 – 894; 1996. [36] Michel, T.; Li, G. K.; Busconi, L. Phosphorylation and subcellular translocation of endothelial nitric oxide synthase. Proc. Natl. Acad. Sci. USA 90:6252– 6256; 1993. [37] Cho, H. J.; Martin, E.; Xie, Q. W.; Sassa, S.; Nathan, C. Inducible nitric oxide synthase: identification of amino acid residues essential for dimerization and binding of tetrahydrobiopterin. Proc. Natl. Acad. Sci. USA 92:11514 –11518; 1995. [38] Kone, B. C. Protein-protein interactions controlling nitric oxide synthases. Acta Physiol. Scand. 168:27–31; 2000. [39] Govers, R.; Rabelink, T. J. Cellular regulation of endothelial nitric oxide synthase. Am. J. Physiol. Renal Physiol. 280:F193– F206; 2001. [40] Geller, D. A.; Billiar, T. R. Molecular biology of nitric oxide synthases. Cancer Metastasis Rev. 17:7–23; 1998. [41] Thomsen, L. L.; Lawton, F. G.; Knowles, R. G.; Beesley, J. E.; Riveros-Moreno, V.; Moncada, S. Nitric oxide synthase activity in human gynecological cancer. Cancer Res. 54:1352–1354; 1994. [42] Thomsen, L. L.; Miles, D. W.; Happerfield, L.; Bobrow, L. G.; Knowles, R. G.; Moncada, S. Nitric oxide synthase activity in human breast cancer. Br. J. Cancer 72:41– 44; 1995. [43] Cobbs, C. S.; Brenman, J. E.; Aldape, K. D.; Bredt, D. S.; Israel, M. A. Expression of nitric oxide synthase in human central nervous system tumors. Cancer Res. 55:727–730; 1995. [44] Koh, E.; Noh, S. H.; Lee, Y. D.; Lee, H. Y.; Han, J. W.; Lee, H. W.; Hong, S. Differential expression of nitric oxide synthase in human stomach cancer. Cancer Lett. 146:173–180; 1999. [45] Mendes, R. V.; Martins, A. R.; de Nucci, G.; Murad, F.; Soares, F. A. Expression of nitric oxide synthase isoforms and nitrotyrosine immunoreactivity by B-cell non-Hodgkin’s lymphomas and multiple myeloma. Histopathology 39:172–178; 2001. [46] Wolf, H.; Haeckel, C.; Roessner, A. Inducible nitric oxide synthase expression in human urinary bladder cancer. Virchows Arch. 437:662– 666; 2000. [47] Baltaci, S.; Orhan, D.; Gogus, C.; Turkolmez, K.; Tulunay, O.; Gogus, O. Inducible nitric oxide synthase expression in benign prostatic hyperplasia, low- and high-grade prostatic intraepithelial neoplasia and prostatic carcinoma. BJU Int. 88:100 –103; 2001. [48] Vakkala, M.; Kahlos, K.; Lakari, E.; Paakko, P.; Kinnula, V.; Soini, Y. Inducible nitric oxide synthase expression, apoptosis, and angiogenesis in in situ and invasive breast carcinomas. Clin. Cancer Res. 6:2408 –2416; 2000. [49] Tschugguel, W.; Schneeberger, C.; Unfried, G.; Czerwenka, K.; Weninger, W.; Mildner, M.; Gruber, D. M.; Sator, M. O.; Waldhor, T.; Huber, J. C. Expression of inducible nitric oxide synthase in human breast cancer depends on tumor grade. Breast Cancer Res. Treat. 56:145–151; 1999. [50] Singer, I. I.; Kawka, D. W.; Scott, S.; Weidner, J. R.; Mumford, R. A.; Riehl, T. E.; Stenson, W. F. Expression of inducible nitric oxide synthase and nitrotyrosine in colonic epithelium in inflammatory bowel disease. Gastroenterology 111:871– 885; 1996. [51] Kimura, H.; Hokari, R.; Miura, S.; Shigematsu, T.; Hirokawa, M.; Akiba, Y.; Kurose, I.; Higuchi, H.; Fujimori, H.; Tsuzuki, Y.; Serizawa, H.; Ishii, H. Increased expression of an inducible isoform of nitric oxide synthase and the formation of peroxynitrite in colonic mucosa of patients with active ulcerative colitis. Gut 42:180 –187; 1998. [52] Dijkstra, G.; Moshage, H.; van Dullemen, H. M.; Jager-Krikken, A.; Tiebosch, A. T.; Kleibeuker, J. H.; Jansen, P. L.; van Goor, H. Expression of nitric oxide synthases and formation of nitrotyrosine and reactive oxygen species in inflammatory bowel disease. J. Pathol. 186:416 – 421; 1998. [53] Mannick, E. E.; Bravo, L. E.; Zarama, G.; Realpe, J. L.; Zhang, X. J.; Ruiz, B.; Fontham, E. T.; Mera, R.; Miller, M. J.; Correa, P. Inducible nitric oxide synthase, nitrotyrosine, and apoptosis in

964

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63] [64]

[65]

[66]

[67]

[68]

[69]

L. J. HOFSETH et al. Helicobacter pylori gastritis: effect of antibiotics and antioxidants. Cancer Res. 56:3238 –3243; 1996. Goto, T.; Haruma, K.; Kitadai, Y.; Ito, M.; Yoshihara, M.; Sumii, K.; Hayakawa, N.; Kajiyama, G. Enhanced expression of inducible nitric oxide synthase and nitrotyrosine in gastric mucosa of gastric cancer patients. Clin. Cancer Res. 5:1411–1415; 1999. Fu, S.; Ramanujam, K. S.; Wong, A.; Fantry, G. T.; Drachenberg, C. B.; James, S. P.; Meltzer, S. J.; Wilson, K. T. Increased expression and cellular localization of inducible nitric oxide synthase and cyclooxygenase 2 in Helicobacter pylori gastritis. Gastroenterology 116:1319 –1329; 1999. Kane, J. M. 3rd; Shears, L. L. 2nd; Hierholzer, C.; Ambs, S.; Billiar, T. R.; Posner, M. C. Chronic hepatitis C virus infection in humans: induction of hepatic nitric oxide synthase and proposed mechanisms for carcinogenesis. J. Surg. Res. 69:321–324; 1997. Majano, P. L.; Garcia-Monzon, C.; Lopez-Cabrera, M.; LaraPezzi, E.; Fernandez-Ruiz, E.; Garcia-Iglesias, C.; Borque, M. J.; Moreno-Otero, R. Inducible nitric oxide synthase expression in chronic viral hepatitis. Evidence for a virus-induced gene upregulation. J. Clin. Invest. 101:1343–1352; 1998. Garcia-Monzon, C.; Majano, P. L.; Zubia, I.; Sanz, P.; Apolinario, A.; Moreno-Otero, R. Intrahepatic accumulation of nitrotyrosine in chronic viral hepatitis is associated with histological severity of liver disease. J. Hepatol. 32:331–338; 2000. Cuzzocrea, S.; Zingarelli, B.; Villari, D.; Caputi, A. P.; Longo, G. Evidence for in vivo peroxynitrite production in human chronic hepatitis. Life Sci. 63:L25–L30; 1998. Hussain, S. P.; Raja, K.; Amstad, P. A.; Sawyer, M.; Trudel, L. J.; Wogan, G. N.; Hofseth, L. J.; Shields, P. G.; Billiar, T. R.; Trautwein, C.; Hohler, T.; Galle, P. R.; Phillips, D. H.; Markin, R.; Marrogi, A. J.; Harris, C. C. Increased p53 mutation load in nontumorous human liver of wilson disease and hemochromatosis: oxyradical overload diseases. Proc. Natl. Acad. Sci. USA 97:12770 –12775; 2000. Marrogi, A. J.; Khan, M. A.; van Gijssel, H. E.; Welsh, J. A.; Rahim, H.; Demetris, A. J.; Kowdley, K. V.; Hussain, S. P.; Nair, J.; Bartsch, M. C.; Okby, N.; Poirier, M. C.; Ishak, K. G.; Harris, C. C. Oxidative stress and p53 mutations in the carcinogenesis of iron overload-associated hepatocellular carcinoma. J. Natl. Cancer Inst. 93:1652–1655; 2001. Wilson, K. T.; Fu, S.; Ramanujam, K. S.; Meltzer, S. J. Increased expression of inducible nitric oxide synthase and cyclooxygenase-2 in Barrett’s esophagus and associated adenocarcinomas. Cancer Res. 58:2929 –2934; 1998. Tamir, S.; Burney, S.; Tannenbaum, S. R. DNA damage by nitric oxide. Chem. Res. Toxicol. 9:821– 827; 1996. Zhuang, J. C.; Wright, T. L.; deRojas-Walker, T.; Tannenbaum, S. R.; Wogan, G. N. Nitric oxide-induced mutations in the HPRT gene of human lymphoblastoid TK6 cells and in Salmonella typhimurium. Environ. Mol. Mutagen. 35:39 – 47; 2000. Wink, D. A.; Cook, J. A.; Pacelli, R.; DeGraff, W.; Gamson, J.; Liebmann, J.; Krishna, M. C.; Mitchell, J. B. The effect of various nitric oxide-donor agents on hydrogen peroxide-mediated toxicity: a direct correlation between nitric oxide formation and protection. Arch. Biochem. Biophys. 331:241–248; 1996. Heller, R.; Polack, T.; Grabner, R.; Till, U. Nitric oxide inhibits proliferation of human endothelial cells via a mechanism independent of cGMP. Atherosclerosis 144:49 –57; 1999. Kanamaru, Y.; Takada, T.; Saura, R.; Mizuno, K. Effect of nitric oxide on mouse clonal osteogenic cell, MC3T3-E1, proliferation in vitro. Kobe J. Med. Sci. 47:1–11; 2001. Ulibarri, J. A.; Mozdziak, P. E.; Schultz, E.; Cook, C.; Best, T. M. Nitric oxide donors, sodium nitroprusside and S-nitrosoN-acetylpencillamine, stimulate myoblast proliferation in vitro. In Vitro Cell. Dev. Biol. Anim. 35:215–218; 1999. McCafferty, D. M.; Miampamba, M.; Sihota, E.; Sharkey, K. A.; Kubes, P. Role of inducible nitric oxide synthase in trinitrobenzene sulphonic acid induced colitis in mice. Gut 45:864 – 873; 1999.

[70] Zingarelli, B.; Szabo, C.; Salzman, A. L. Reduced oxidative and nitrosative damage in murine experimental colitis in the absence of inducible nitric oxide synthase. Gut 45:199 –209; 1999. [71] Peng, H. B.; Rajavashisth, T. B.; Libby, P.; Liao, J. K. Nitric oxide inhibits macrophage-colony stimulating factor gene transcription in vascular endothelial cells. J. Biol. Chem. 270:17050 –17055; 1995. [72] Berendji-Grun, D.; Kolb-Bachofen, V.; Kroncke, K. D. Nitric oxide inhibits endothelial IL-1(beta)-induced ICAM-1 gene expression at the transcriptional level decreasing Sp1 and AP-1 activity. Mol. Med. 7:748 –754; 2001. [73] De Caterina, R.; Libby, P.; Peng, H. B.; Thannickal, V. J.; Rajavashisth, T. B.; Gimbrone, M. A. Jr.; Shin, W. S.; Liao, J. K. Nitric oxide decreases cytokine-induced endothelial activation. Nitric oxide selectively reduces endothelial expression of adhesion molecules and proinflammatory cytokines. J. Clin. Invest. 96:60 – 68; 1995. [74] Clancy, R.; Varenika, B.; Huang, W.; Ballou, L.; Attur, M.; Amin, A. R.; Abramson, S. B. Nitric oxide synthase/COX crosstalk: nitric oxide activates COX-1 but inhibits COX-2-derived prostaglandin production. J. Immunol. 165:1582–1587; 2000. [75] Stadler, J.; Harbrecht, B. G.; Di Silvio, M.; Curran, R. D.; Jordan, M. L.; Simmons, R. L.; Billiar, T. R. Endogenous nitric oxide inhibits the synthesis of cyclooxygenase products and interleukin-6 by rat Kupffer cells. J. Leukoc. Biol. 53:165–172; 1993. [76] Gurjar, M. V.; DeLeon, J.; Sharma, R. V.; Bhalla, R. C. Mechanism of inhibition of matrix metalloproteinase-9 induction by NO in vascular smooth muscle cells. J. Appl. Physiol. 91:1380 – 1386; 2001. [77] Park, S. K.; Lin, H. L.; Murphy, S. Nitric oxide regulates nitric oxide synthase-2 gene expression by inhibiting NF-kappaB binding to DNA. Biochem. J. 322:609 – 613; 1997. [78] Peng, H. B.; Spiecker, M.; Liao, J. K. Inducible nitric oxide: an autoregulatory feedback inhibitor of vascular inflammation. J. Immunol. 161:1970 –1976; 1998. [79] Sekkai, D.; Aillet, F.; Israel, N.; Lepoivre, M. Inhibition of NF-kappaB and HIV-1 long terminal repeat transcriptional activation by inducible nitric oxide synthase 2 activity. J. Biol. Chem. 273:3895–3900; 1998. [80] Laroux, F. S.; Pavlick, K. P.; Hines, I. N.; Kawachi, S.; Harada, H.; Bharwani, S.; Hoffman, J. M.; Grisham, M. B. Role of nitric oxide in inflammation. Acta Physiol. Scand. 173:113–118; 2001. [81] Orucevic, A.; Lala, P. K. Role of nitric oxide in IL-2 therapyinduced capillary leak syndrome. Cancer Metastasis Rev. 17: 127–142; 1998. [82] Thomsen, L. L.; Miles, D. W. Role of nitric oxide in tumour progression: lessons from human tumours. Cancer Metastasis Rev. 17:107–118; 1998. [83] Lala, P. K.; Orucevic, A. Role of nitric oxide in tumor progression: lessons from experimental tumors. Cancer Metastasis Rev. 17:91–106; 1998. [84] Fukumura, D.; Jain, R. K. Role of nitric oxide in angiogenesis and microcirculation in tumors. Cancer Metastasis Rev. 17:77– 89; 1998. [85] Felley-Bosco, E. Role of nitric oxide in genotoxicity: implication for carcinogenesis. Cancer Metastasis Rev. 17:25–37; 1998. [86] Lala, P. K. Significance of nitric oxide in carcinogenesis, tumor progression and cancer therapy. Cancer Metastasis Rev. 17:1– 6; 1998. [87] Xie, K.; Fidler, I. J. Therapy of cancer metastasis by activation of the inducible nitric oxide synthase. Cancer Metastasis Rev. 17:55–75; 1998. [88] Jenkins, D. C.; Charles, I. G.; Thomsen, L. L.; Moss, D. W.; Holmes, L. S.; Baylis, S. A.; Rhodes, P.; Westmore, K.; Emson, P. C.; Moncada, S. Roles of nitric oxide in tumor growth. Proc. Natl. Acad. Sci USA 92:4392– 4396; 1995. [89] Maeda, H.; Noguchi, Y.; Sato, K.; Akaike, T. Enhanced vascular permeability in solid tumor is mediated by nitric oxide and inhibited by both new nitric oxide scavenger and nitric oxide synthase inhibitor. Jpn. J. Cancer Res. 85:331–334; 1994.

Cancer and chemoprevention [90] Tozer, G. M.; Prise, V. E.; Chaplin, D. J. Inhibition of nitric oxide synthase induces a selective reduction in tumor blood flow that is reversible with L-arginine. Cancer Res. 57:948 –955; 1997. [91] Nicotera, P.; Bonfoco, E.; Brune, B. Mechanisms for nitric oxide-induced cell death: involvement of apoptosis. Adv. Neuroimmunol. 5:411– 420; 1997. [92] Dimmeler, S.; Haendeler, J.; Nehls, M.; Zeiher, A. M. Suppression of apoptosis by nitric oxide via inhibition of interleukin1beta-converting enzyme (ICE)-like and cysteine protease protein (CPP)-32-like proteases. J. Exp. Med. 185:601– 607; 1997. [93] Li, J.; Bombeck, C. A.; Yang, S.; Kim, Y. M.; Billiar, T. R. Nitric oxide suppresses apoptosis via interrupting caspase activation and mitochondrial dysfunction in cultured hepatocytes. J. Biol. Chem. 274:17325–17333; 1999. [94] Chung, H. T.; Pae, H. O.; Choi, B. M.; Billiar, T. R.; Kim, Y. M. Nitric oxide as a bioregulator of apoptosis. Biochem. Biophys. Res. Commun. 282:1075–1079; 2001. [95] Kim, P. K.; Zamora, R.; Petrosko, P.; Billiar, T. R. The regulatory role of nitric oxide in apoptosis. Int. Immunopharmacol. 1:1421–1441; 2001. [96] Melillo, G.; Musso, T.; Sica, A.; Taylor, L. S.; Cox, G. W.; Varesio, L. A hypoxia-responsive element mediates a novel pathway of activation of the inducible nitric oxide synthase promoter. J. Exp. Med. 182:1683–1693; 1995. [97] Tretyakova, N. Y.; Burney, S.; Pamir, B.; Wishnok, J. S.; Dedon, P. C.; Wogan, G. N.; Tannenbaum, S. R. Peroxynitrite-induced DNA damage in the supF gene: correlation with the mutational spectrum. Mutat. Res. 447:287–303; 2000. [98] Zhuang, J. C.; Lin, C.; Lin, D.; Wogan, G. N. Mutagenesis associated with nitric oxide production in macrophages. Proc. Natl. Acad. Sci. USA 95:8286 – 8291; 1998. [99] Wink, D. A.; Hanbauer, I.; Grisham, M. B.; Laval, F.; Nims, R. W.; Laval, J.; Cook, J.; Pacelli, R.; Liebmann, J.; Krishna, M.; Ford, P. C.; Mitchell, J. B. Chemical biology of nitric oxide: regulation and protective and toxic mechanisms. Curr. Top. Cell. Regul. 34:159 –187; 1996. [100] Sibghat-Ullah; Gallinari, P.; Xu, Y. Z.; Goodman, M. F.; Bloom, L. B.; Jiricny, J.; Day, R. S. 3rd. Base analog and neighboring base effects on substrate specificity of recombinant human G:T mismatch-specific thymine DNA-glycosylase. Biochemistry 35: 12926 –12932;1996. [101] Messmer, U. K.; Brune, B. Nitric oxide-induced apoptosis: p53dependent and p53-independent signalling pathways. Biochem. J. 319:299 –305; 1996. [102] Forrester, K.; Ambs, S.; Lupold, S. E.; Kapust, R. B.; Spillare, E. A.; Weinberg, W. C.; Felley-Bosco, E.; Wang, X. W.; Geller, D. A.; Billiar, T. R.; Harris, C. C. Nitric oxide-induced p53 accumulation and regulation of inducible nitric oxide synthase (NOS2) expression by wild-type p53. Proc. Natl. Acad. Sci. USA 93:2442–2447; 1996. [103] Nakaya, N.; Lowe, S. W.; Taya, Y.; Chenchik, A.; Enikolopov, G. Specific pattern of p53 phosphorylation during nitric oxideinduced cell cycle arrest. Oncogene 19:6369 – 6375; 2000. [104] Ambs, S.; Merriam, W. G.; Ogunfusika, M. O.; Bennett, W. P.; Ishibe, N.; Hussain, S. P.; Tzeng, E. E.; Geller, D. A.; Billiar, T. R.; Harris, C. C. p53 and vascular endothelial growth factor regulate tumour growth of NOS2-expressing human carcinoma cells. Nat. Med. 4:1371–1376; 1998. [105] Chin, K.; Kurashima, Y.; Ogura, T.; Tajiri, H.; Yoshida, S.; Esumi, H. Induction of vascular endothelial growth factor by nitric oxide in human glioblastoma and hepatocellular carcinoma cells. Oncogene 15:437– 442; 1997. [106] Frank, S.; Stallmeyer, B.; Kampfer, H.; Schaffner, C.; Pfeilschifter, J. Differential regulation of vascular endothelial growth factor and its receptor fms-like-tyrosine kinase is mediated by nitric oxide in rat renal mesangial cells. Biochem. J. 338:367–374; 1999. [107] Papapetropoulos, A.; Garcia-Cardena, G.; Madri, J. A.; Sessa, W. C. Nitric oxide production contributes to the angiogenic

[108] [109]

[110]

[111]

[112]

[113]

[114]

[115]

[116]

[117]

[118] [119]

[120] [121]

[122]

[123] [124]

[125]

[126]

965

properties of vascular endothelial growth factor in human endothelial cells. J. Clin. Invest. 100:3131–3139; 1997. Sharp, P. A. RNA interference—2001. Genes Dev. 15:485– 490; 2001. Sandau, K. B.; Zhou, J.; Kietzmann, T.; Brune, B. Regulation of the hypoxia-inducible factor 1alpha by the inflammatory mediators nitric oxide and tumor necrosis factor-alpha in contrast to desferroxamine and phenylarsine oxide. J. Biol. Chem. 276: 39805–39811; 2001. Sandau, K. B.; Fandrey, J.; Brune, B Accumulation of HIF1alpha under the influence of nitric oxide. Blood 97:1009 –1015; 2001. Ravi, R.; Mookerjee, B.; Bhujwalla, Z. M.; Sutter, C. H.; Artemov, D.; Zeng, Q.; Dillehay, L. E.; Madan, A.; Semenza, G. L.; Bedi, A. Regulation of tumor angiogenesis by p53-induced degradation of hypoxia-inducible factor 1alpha. Genes Dev. 14: 34 – 44; 2000. Ambs, S.; Ogunfusika, M. O.; Merriam, W. G.; Bennett, W. P.; Billiar, T. R.; Harris, C. C. Upregulation of NOS2 expression in cancer-prone p53 knockout mice. Proc. Natl. Acad. Sci. USA 95:8823– 8828; 1998. Ambs, S.; Bennett, W. P.; Merriam, W. G.; Ogunfusika, M. O.; Oser, S. M.; Harrington, A. M.; Shields, P. G.; Felley-Bosco, E.; Hussain, S. P.; Harris, C. C. Relationship between p53 mutations and inducible nitric oxide synthase expression in human colorectal cancer. J. Natl. Cancer Inst. 91:86 – 88; 1999. Hussain, S. P.; Amstad, P.; Raja, K.; Ambs, S.; Nagashima, M.; Bennett, W. P.; Shields, P. G.; Ham, A. J.; Swenberg, J. A.; Marrogi, A. J.; Harris, C. C. Increased p53 mutation load in noncancerous colon tissue from ulcerative colitis: a cancer-prone chronic inflammatory disease. Cancer Res. 60:3333–3337; 2000. Umetani, N.; Sasaki, S.; Watanabe, T.; Shinozaki, M.; Matsuda, K.; Ishigami, H.; Ueda, E.; Muto, T. Genetic alterations in ulcerative colitis-associated neoplasia focusing on APC, K-ras gene and microsatellite instability. Jpn. J. Cancer Res. 90:1081– 1087; 1999. Ambs, S.; Merriam, W. G.; Bennett, W. P.; Felley-Bosco, E.; Ogunfusika, M. O.; Oser, S. M.; Klein, S.; Shields, P. G.; Billiar, T. R.; Harris, C. C. Frequent nitric oxide synthase-2 expression in human colon adenomas: implication for tumor angiogenesis and colon cancer progression. Cancer Res. 58:334 –341; 1998. Alleva, D. G.; Burger, C. J.; Elgert, K. D. Tumor-induced regulation of suppressor macrophage nitric oxide and TNF-alpha production. Role of tumor-derived IL-10, TGF-beta, and prostaglandin E2. J. Immunol. 153:1674 –1686; 1994. Hollstein, M.; Sidransky, D.; Vogelstein, B.; Harris, C. C. p53 mutations in human cancers. Science 253:49 –53; 1991. Greenblatt, M. S.; Bennett, W. P.; Hollstein, M.; Harris, C. C. Mutations in the p53 tumor suppressor gene: clues to cancer etiology and molecular pathogenesis. Cancer Res. 54:4855– 4878; 1994. Levine, A. J.; Momand, J.; Finlay, C. A. The p53 tumour suppressor gene. Nature 351:453– 456; 1991. Ellie, E.; Loiseau, H.; Lafond, F.; Arsaut, J.; Demotes-Mainard, J. Differential expression of inducible nitric oxide synthase mRNA in human brain tumours. Neuroreport 7:294 –296; 1995. Gallo, O.; Masini, E.; Morbidelli, L.; Franchi, A.; Fini-Storchi, I.; Vergari, W. A.; Ziche, M. Role of nitric oxide in angiogenesis and tumor progression in head and neck cancer. J. Natl. Cancer Inst. 90:587–596; 1998. Balkwill, F.; Mantovani, A. Inflammation and cancer: back to Virchow? Lancet 357:539 –545; 2001. O’Byrne, K. J.; Dalgleish, A. G. Chronic immune activation and inflammation as the cause of malignancy. Br. J. Cancer 85:473– 483; 2001. Ohshima, H.; Bartsch, H. Chronic infections and inflammatory processes as cancer risk factors: possible role of nitric oxide in carcinogenesis. Mutat. Res. 305:253–264; 1994. Christen, S.; Hagen, T. M.; Shigenaga, M. K.; Ames, B. N. Chronic inflammation, mutation, and cancer. In: Parsonnet, J.;

966

[127]

[128]

[129]

[130] [131]

[132] [133]

[134]

[135]

[136]

[137]

[138]

[139]

[140]

[141]

[142]

[143]

[144]

[145]

L. J. HOFSETH et al. Hornig, S., eds. Microbes and malignancy: infection as a cause of cancer. New York: Oxford University Press; 1999:35– 88. Adler, V.; Yin, Z.; Tew, K. D.; Ronai, Z. Role of redox potential and reactive oxygen species in stress signaling. Oncogene 18: 6104 – 6111; 1999. Shackelford, R. E.; Kaufmann, W. K.; Paules, R. S. Oxidative stress and cell cycle checkpoint function. Free Radic. Biol. Med. 28:1387–1404; 2000. Kyriakis, J. M.; Avruch, J. Mammalian mitogen-activated protein kinase signal transduction pathways activated by stress and inflammation. Physiol. Rev. 81:807– 869; 2001. Cerutti, P. A.; Trump, B. F. Inflammation and oxidative stress in carcinogenesis. Cancer Cells 3:1–7; 1991. Shalon, D.; Smith, S. J.; Brown, P. O. A DNA microarray system for analyzing complex DNA samples using two-color fluorescent probe hybridization. Genome Res. 6:639 – 645; 1996. Cerutti, P. A. Prooxidant states and tumor promotion. Science 227:375–381; 1985. MacMicking, J. D.; Nathan, C.; Hom, G.; Chartrain, N.; Fletcher, D. S.; Trumbauer, M.; Stevens, K.; Xie, Q. W.; Sokol, K.; Hutchinson, N. Altered responses to bacterial infection and endotoxic shock in mice lacking inducible nitric oxide synthase. Cell 81:641– 650; 1995. Hokari, R.; Kato, S.; Matsuzaki, K.; Kuroki, M.; Iwai, A.; Kawaguchi, A.; Nagao, S.; Miyahara, T.; Itoh, K.; Sekizuka, E.; Nagata, H.; Ishii, H.; Miura, S. Reduced sensitivity of inducible nitric oxide synthase-deficient mice to chronic colitis. Free Radic. Biol. Med. 31:153–163; 2001. Krieglstein, C. F.; Cerwinka, W. H.; Laroux, F. S.; Salter, J. W.; Russell, J. M.; Schuermann, G.; Grisham, M. B.; Ross, C. R.; Granger, D. N. Regulation of murine intestinal inflammation by reactive metabolites of oxygen and nitrogen: divergent roles of superoxide and nitric oxide. J. Exp. Med. 194:1207–1218; 2001. Konopka, T. E.; Barker, J. E.; Bamford, T. L.; Guida, E.; Anderson, R. L.; Stewart, A. G. Nitric oxide synthase II gene disruption: implications for tumor growth and vascular endothelial growth factor production. Cancer Res. 61:3182–3187; 2001. Cooper, H. S.; Everley, L.; Chang, W. C.; Pfeiffer, G.; Lee, B.; Murthy, S.; Clapper, M. L. The role of mutant Apc in the development of dysplasia and cancer in the mouse model of dextran sulfate sodium-induced colitis. Gastroenterology 121: 1407–1416; 2001. Ahn, B.; Ohshima, H. Suppression of intestinal polyposis in Apc(Min/⫹) mice by inhibiting nitric oxide production. Cancer Res. 61:8357– 8360; 2001. Yamamoto, Y.; Gaynor, R. B. Therapeutic potential of inhibition of the NF-kappaB pathway in the treatment of inflammation and cancer. J. Clin. Invest. 107:135–142; 2001. Tamir, S.; deRojas-Walker, T.; Gal, A.; Weller, A. H.; Li, X.; Fox, J. G.; Wogan, G. N.; Tannenbaum, S. R. Nitric oxide production in relation to spontaneous B-cell lymphoma and myositis in SJL mice. Cancer Res. 55:4391– 4397; 1995. Gal, A.; Tamir, S.; Tannenbaum, S. R.; Wogan, G. N. Nitric oxide production in SJL mice bearing the RcsX lymphoma: a model for in vivo toxicological evaluation of NO. Proc. Natl. Acad. Sci. USA 93:11499 –11503; 1996. Gal, A.; Wogan, G. N. Mutagenesis associated with nitric oxide production in transgenic SJL mice. Proc. Natl. Acad. Sci. USA 93:15102–15107; 1996. Ahn, B.; Han, B. S.; Kim, D. J.; Ohshima, H. Immunohistochemical localization of inducible nitric oxide synthase and 3-nitrotyrosine in rat liver tumors induced by N-nitrosodiethylamine. Carcinogenesis 20:1337–1344; 1999. Nair, J.; Gal, A.; Tamir, S.; Tannenbaum, S. R.; Wogan, G. N.; Bartsch, H. Etheno adducts in spleen DNA of SJL mice stimulated to overproduce nitric oxide. Carcinogenesis 19:2081–2084; 1998. Goldstein, S. R.; Yang, G. Y.; Chen, X.; Curtis, S. K.; Yang, C. S. Studies of iron deposits, inducible nitric oxide synthase and nitrotyrosine in a rat model for esophageal adenocarcinoma. Carcinogenesis 19:1445–1449; 1998.

[146] Okamoto, T.; Masuda, Y.; Kawasaki, T.; Shinohara, M.; Matsuzaki, K. Aminoguanidine prevents concanavalin A-induced hepatitis in mice. Eur. J. Pharmacol. 396:125–130; 2000. [147] Yasuhiro, T.; Korolkiewicz, R. P.; Kato, S.; Takeuchi, K. Role of nitric oxide in pathogenesis of serotonine-induced gastric lesions in rats. Pharmacol. Res. 36:333–338; 1997. [148] Rao, C. V.; Indranie, C.; Simi, B.; Manning, P. T.; Connor, J. R.; Reddy, B. S. Chemopreventive properties of a selective inducible nitric oxide synthase inhibitor in colon carcinogenesis, administered alone or in combination with celecoxib, a selective cyclooxygenase-2 inhibitor. Cancer Res. 62:165–170; 2002. [149] Rao, C. V.; Kawamori, T.; Hamid, R.; Reddy, B. S. Chemoprevention of colonic aberrant crypt foci by an inducible nitric oxide synthase-selective inhibitor. Carcinogenesis 20:641– 644; 1999. [150] Kawamori, T.; Takahashi, M.; Watanabe, K.; Ohta, T.; Nakatsugi, S.; Sugimura, T.; Wakabayashi, K. Suppression of azoxymethane-induced colonic aberrant crypt foci by a nitric oxide synthase inhibitor. Cancer Lett. 148:33–37; 2000. [151] Doi, K.; Akaike, T.; Fujii, S.; Tanaka, S.; Ikebe, N.; Beppu, T.; Shibahara, S.; Ogawa, M.; Maeda, H. Induction of haem oxygenase-1 nitric oxide and ischaemia in experimental solid tumours and implications for tumour growth. Br. J. Cancer 80: 1945–1954; 1999. [152] Thomsen, L. L.; Scott, J. M.; Topley, P.; Knowles, R. G.; Keerie, A. J.; Frend, A. J. Selective inhibition of inducible nitric oxide synthase inhibits tumor growth in vivo: studies with 1400W, a novel inhibitor. Cancer Res. 57:3300 –3304; 1997. [153] Tozer, G. M.; Prise, V. E.; Wilson, J.; Locke, R. J.; Vojnovic, B.; Stratford, M. R.; Dennis, M. F.; Chaplin, D. J. Combretastatin A-4 phosphate as a tumor vascular-targeting agent: early effects in tumors and normal tissues. Cancer Res. 59:1626 –1634; 1999. [154] Tozer, G. M.; Prise, V. E.; Motterlini, R.; Poole, B. A.; Wilson, J.; Chaplin, D. J. The comparative effects of the NOS inhibitor, Nomega-nitro-L-arginine, and the haemoxygenase inhibitor, zinc protoporphyrin IX, on tumour blood flow. Int. J. Radiat. Oncol. Biol. Phys. 42:849 – 853; 1998. [155] Ziche, M.; Morbidelli, L.; Masini, E.; Amerini, S.; Granger, H. J.; Maggi, C. A.; Geppetti, P.; Ledda, F. Nitric oxide mediates angiogenesis in vivo and endothelial cell growth and migration in vitro promoted by substance P. J. Clin. Invest. 94:2036 –2044; 1994. [156] Orucevic, A.; Lala, P. K. NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, ameliorates interleukin 2-induced capillary leakage and reduces tumour growth in adenocarcinoma-bearing mice. Br. J. Cancer 73:189 –196; 1996. [157] Ribbons, K. A.; Currie, M. G.; Connor, J. R.; Manning, P. T.; Allen, P. C.; Didier, P.; Ratterree, M. S.; Clark, D. A.; Miller, M. J. The effect of inhibitors of inducible nitric oxide synthase on chronic colitis in the rhesus monkey. J. Pharmacol. Exp. Ther. 280:1008 –1015; 1997. [158] Yoshida, Y.; Iwai, A.; Itoh, K.; Tanaka, M.; Kato, S.; Hokari, R.; Miyahara, T.; Koyama, H.; Miura, S.; Kobayashi, M. Role of inducible nitric oxide synthase in dextran sulphate sodiuminduced colitis. Aliment. Pharmacol. Ther. 14(Suppl. 1):26 –32; 2000. [159] Wink, D. A.; Hanbauer, I.; Krishna, M. C.; DeGraff, W.; Gamson, J.; Mitchell, J. B. Nitric oxide protects against cellular damage and cytotoxicity from reactive oxygen species. Proc. Natl. Acad. Sci. USA 90:9813–9817; 1993. [160] Schleiffer, R.; Duranton, B.; Gosse, F.; Bergmann, C.; Raul, F. Nitric oxide synthase inhibition promotes carcinogen-induced preneoplastic changes in the colon of rats. Nitric Oxide 4:583– 589; 2000. [161] Bruns, C. J.; Shinohara, H.; Harbison, M. T.; Davis, D. W.; Nelkin, G.; Killion, J. J.; McConkey, D. J.; Dong, Z.; Fidler, I. J. Therapy of human pancreatic carcinoma implants by irinotecan and the oral immunomodulator JBT 3002 is associated with enhanced expression of inducible nitric oxide synthase in tumorinfiltrating macrophages. Cancer Res. 60:2–7; 2000. [162] Shinohara, H.; Bucana, C. D.; Killion, J. J.; Fidler, I. J. Inten-

Cancer and chemoprevention

[163]

[164]

[165]

[166]

[167]

[168]

[169]

[170]

[171]

[172]

[173]

[174]

[175]

[176]

[177]

[178]

sified regression of colon cancer liver metastases in mice treated with irinotecan and the immunomodulator JBT 3002. J. Immunother. 23:321–331; 2000. Yamamoto, T.; Terada, N.; Seiyama, A.; Nishizawa, Y.; Akedo, H.; Kosaka, H. Increase in experimental pulmonary metastasis in mice by L-arginine under inhibition of nitric oxide production by NG-nitro-L-arginine methyl ester. Int. J. Cancer 75:140 –144; 1998. Iwasaki, T.; Higashiyama, M.; Kuriyama, K.; Sasaki, A.; Mukai, M.; Shinkai, K.; Horai, T.; Matsuda, H.; Akedo, H. NG-nitroL-arginine methyl ester inhibits bone metastasis after modified intracardiac injection of human breast cancer cells in a nude mouse model. Jpn. J. Cancer Res. 88:861– 866; 1997. Edwards, P.; Cendan, J. C.; Topping, D. B.; Moldawer, L. L.; MacKay, S.; Copeland, E. M. III; Lind, D. S. Tumor cell nitric oxide inhibits cell growth in vitro, but stimulates tumorigenesis and experimental lung metastasis in vivo. J. Surg. Res. 63:49 – 52; 1996. Wang, B.; Xiong, Q.; Shi, Q.; Tan, D.; Le, X.; Xie, K. Genetic disruption of host nitric oxide synthase II gene impairs melanoma-induced angiogenesis and suppresses pleural effusion. Int. J. Cancer 91:607– 611; 2001. Wang, B.; Xiong, Q.; Shi, Q.; Le, X.; Abbruzzese, J. L.; Xie, K. Intact nitric oxide synthase II gene is required for interferonbeta-mediated suppression of growth and metastasis of pancreatic adenocarcinoma. Cancer Res. 61:71–75; 2001. Shi, Q.; Xiong, Q.; Wang, B.; Le, X.; Khan, N. A.; Xie, K. Influence of nitric oxide synthase II gene disruption on tumor growth and metastasis. Cancer Res. 60:2579 –2583; 2000. Shi, Q.; Huang, S.; Jiang, W.; Kutach, L. S.; Ananthaswamy, H. N.; Xie, K. Direct correlation between nitric oxide synthase II inducibility and metastatic ability of UV-2237 murine fibrosarcoma cells carrying mutant p53. Cancer Res. 59:2072–2075; 1999. Juang, S. H.; Xie, K.; Xu, L.; Shi, Q.; Wang, Y.; Yoneda, J.; Fidler, I. J. Suppression of tumorigenicity and metastasis of human renal carcinoma cells by infection with retroviral vectors harboring the murine inducible nitric oxide synthase gene. Hum. Gene Ther. 9:845– 854; 1998. Xie, K.; Huang, S.; Dong, Z.; Gutman, M.; Fidler, I. J. Direct correlation between expression of endogenous inducible nitric oxide synthase and regression of M5076 reticulum cell sarcoma hepatic metastases in mice treated with liposomes containing lipopeptide CGP 31362. Cancer Res. 55:3123–3131; 1995. Xie, K.; Dong, Z.; Fidler, I. J. Activation of nitric oxide synthase gene for inhibition of cancer metastasis. J. Leukoc. Biol. 59:797– 803; 1996. Dong, Z.; Staroselsky, A. H.; Qi, X.; Xie, K.; Fidler, I. J. Inverse correlation between expression of inducible nitric oxide synthase activity and production of metastasis in K-1735 murine melanoma cells. Cancer Res. 54:789 –793; 1994. Xie, K.; Huang, S.; Dong, Z.; Juang, S. H.; Gutman, M.; Xie, Q. W.; Nathan, C.; Fidler, I. J. Transfection with the inducible nitric oxide synthase gene suppresses tumorigenicity and abrogates metastasis by K-1735 murine melanoma cells. J. Exp. Med. 181:1333–1343; 1995. Xie, K.; Huang, S.; Dong, Z.; Juang, S. H.; Wang, Y.; Fidler, I. J. Destruction of bystander cells by tumor cells transfected with inducible nitric oxide (NO) synthase gene. J. Natl. Cancer Inst. 89:421– 427; 1997. Matthews, N. E.; Adams, M. A.; Maxwell, L. R.; Gofton, T. E.; Graham, C. H. Nitric oxide-mediated regulation of chemosensitivity in cancer cells. J. Natl. Cancer Inst. 93:1879 –1885; 2001. Janssens, M. Y.; Van den Berge, D. L.; Verovski, V. N.; Monsaert, C.; Storme, G. A. Activation of inducible nitric oxide synthase results in nitric oxide-mediated radiosensitization of hypoxic EMT-6 tumor cells. Cancer Res. 58:5646 –5648; 1998. Maccarrone, M.; Fantini, C.; Ranalli, M.; Melino, G.; Agro, A. F. Activation of nitric oxide synthase is involved in tamoxifen-induced apoptosis of human erythroleukemia K562 cells. FEBS Lett. 434:421– 424; 1998.

967

[179] Ho, Y. S.; Wang, Y. J.; Lin, J. K. Induction of p53 and p21/ WAF1/CIP1 expression by nitric oxide and their association with apoptosis in human cancer cells. Mol. Carcinog. 16:20 –31; 1996. [180] Bartsch, H. Studies on biomarkers in cancer etiology and prevention: a summary and challenge of 20 years of interdisciplinary research. Mutat. Res. 462:255–279; 2000. [181] Marnett, L. J. Oxyradicals and DNA damage. Carcinogenesis 21:361–370; 2000. [182] Burney, S.; Caulfield, J. L.; Niles, J. C.; Wishnok, J. S.; Tannenbaum, S. R. The chemistry of DNA damage from nitric oxide and peroxynitrite. Mutat. Res. 424:37– 49; 1999. [183] Marnett, L. J.; Plastaras, J. P. Endogenous DNA damage and mutation. Trends Genet. 17:214 –221; 2001. [184] Aguilar, F.; Harris, C. C.; Sun, T.; Hollstein, M.; Cerutti, P. Geographic variation of p53 mutational profile in nonmalignant human liver. Science 264:1317–1319; 1994. [185] Aguilar, F.; Hussain, S. P.; Cerutti, P. Aflatoxin B1 induces the transversion of G3 T in codon 249 of the p53 tumor suppressor gene in human hepatocytes. Proc. Natl. Acad. Sci. USA 90: 8586 – 8590; 1993. [186] Hussain, S. P.; Aguilar, F.; Amstad, P.; Cerutti, P. Oxy-radical induced mutagenesis of hotspot codons 248 and 249 of the human p53 gene. Oncogene 9:2277–2281; 1994. [187] Hussain, S. P.; Aguilar, F.; Cerutti, P. Mutagenesis of codon 248 of the human p53 tumor suppressor gene by N-ethyl-N-nitrosourea. Oncogene 9:13–18; 1994. [188] Hussain, S. P.; Kennedy, C. H.; Amstad, P.; Lui, H.; Lechner, J. F.; Harris, C. C. Radon and lung carcinogenesis: mutability of p53 codons 249 and 250 to 238Pu alpha-particles in human bronchial epithelial cells. Carcinogenesis 18:121–125; 1997. [189] Niederau, C.; Fischer, R.; Sonnenberg, A.; Stremmel, W.; Trampisch, H. J.; Strohmeyer, G. Survival and causes of death in cirrhotic and in noncirrhotic patients with primary hemochromatosis. N. Engl. J. Med. 313:1256 –1262; 1985. [190] Gillen, C. D.; Walmsley, R. S.; Prior, P.; Andrews, H. A.; Allan, R. N. Ulcerative colitis and Crohn’s disease: a comparison of the colorectal cancer risk in extensive colitis. Gut 35:1590 –1592; 1994. [191] Guihot, G.; Guimbaud, R.; Bertrand, V.; Narcy-Lambare, B.; Couturier, D.; Duee, P. H.; Chaussade, S.; Blachier, F. Inducible nitric oxide synthase activity in colon biopsies from inflammatory areas: correlation with inflammation intensity in patients with ulcerative colitis but not with Crohn’s disease. Amino Acids 18:229 –237; 2000. [192] Boughton-Smith, N. K. Pathological and therapeutic implications for nitric oxide in inflammatory bowel disease. J. R. Soc. Med. 87:312–314; 1994. [193] Leonard, N.; Bishop, A. E.; Polak, J. M.; Talbot, I. C. Expression of nitric oxide synthase in inflammatory bowel disease is not affected by corticosteroid treatment. J. Clin. Pathol. 51:750 – 753; 1998. [194] Ekbom, A.; Helmick, C.; Zack, M.; Adami, H. O. Ulcerative colitis and colorectal cancer. A population-based study. N. Engl. J Med. 323:1228 –1233; 1990. [195] Iwashita, E.; Iwai, A.; Sawazaki, Y.; Matsuda, K.; Miyahara, T.; Itoh, K. Activation of microvascular endothelial cells in active ulcerative colitis and detection of inducible nitric oxide synthase. J. Clin. Gastroenterol. 27(suppl. 1):S74 –S79; 1998. [196] Shin, H. R.; Lee, C. U.; Park, H. J.; Seol, S. Y.; Chung, J. M.; Choi, H. C.; Ahn, Y. O.; Shigemastu, T. Hepatitis B and C virus, Clonorchis sinensis for the risk of liver cancer: a case-control study in Pusan, Korea. Int. J. Epidemiol. 25:933–940; 1996. [197] Kane, J. M. III; Shears, L. L.; Hierholzer, C.; Ambs, S.; Billiar, T. R.; Posner, M. C. Chronic hepatitis C virus infection in humans: induction of hepatic nitric oxide synthase and proposed mechanisms for carcinogenesis. J. Surg. Res. 69:321–324; 1997. [198] Rahman, M. A.; Dhar, D. K.; Yamaguchi, E.; Maruyama, S.; Sato, T.; Hayashi, H.; Ono, T.; Yamanoi, A.; Kohno, H.; Nagasue, N. Coexpression of inducible nitric oxide synthase and COX-2 in hepatocellular carcinoma and surrounding liver: pos-

968

[199] [200]

[201]

[202] [203]

[204]

[205]

[206]

[207]

[208]

[209] [210]

L. J. HOFSETH et al. sible involvement of COX-2 in the angiogenesis of hepatitis C virus-positive cases. Clin. Cancer Res. 7:1325–1332; 2001. Mitchell, H.; Drake, M.; Medley, G. Prospective evaluation of risk of cervical cancer after cytological evidence of human papilloma virus infection. Lancet 1:573–575; 1986. Zhang, Z. F.; Kurtz, R. C.; Klimstra, D. S.; Yu, G. P.; Sun, M.; Harlap, S.; Marshall, J. R. Helicobacter pylori infection on the risk of stomach cancer and chronic atrophic gastritis. Cancer Detect. Prev. 23:357–367; 1999. Tatemichi, M.; Ogura, T.; Nagata, H.; Esumi, H. Enhanced expression of inducible nitric oxide synthase in chronic gastritis with intestinal metaplasia. J. Clin. Gastroenterol. 27:240 –245; 1998. Esrig, D.; McEvoy, K.; Bennett, C. J. Bladder cancer in the spinal cord-injured patient with long-term catheterization: a casual relationship? Semin. Urol. 10:102–108; 1992. Kanoh, K.; Shimura, T.; Tsutsumi, S.; Suzuki, H.; Kashiwabara, K.; Nakajima, T.; Kuwano, H. Significance of contracted cholecystitis lesions as high risk for gallbladder carcinogenesis. Cancer Lett. 169:7–14; 2001. Csendes, A.; Becerra, M.; Burdiles, P.; Demian, I.; Bancalari, K.; Csendes, P. Bacteriological studies of bile from the gallbladder in patients with carcinoma of the gallbladder, cholelithiasis, common bile duct stones and no gallstones disease. Eur. J. Surg. 160:363–367; 1994. Rosin, M. P.; Hofseth, L. J. Schistosomiasis, bladder and colon cancer. In Parsonnet, J., ed. Microbes and Malignancy: Infection as a cause of human cancers. Oxford: Oxford University Press; 1999:313–345. Shochina, M.; Fellig, Y.; Sughayer, M.; Pizov, G.; Vitner, K.; Podeh, D.; Hochberg, A.; Ariel, I. Nitric oxide synthase immunoreactivity in human bladder carcinoma. Mol. Pathol. 54:248 – 252; 2001. Jaiswal, M.; LaRusso, N. F.; Shapiro, R. A.; Billiar, T. R.; Gores, G. J. Nitric oxide-mediated inhibition of DNA repair potentiates oxidative DNA damage in cholangiocytes. Gastroenterology 120:190 –199; 2001. Haswell-Elkins, M. R.; Mairiang, E.; Mairiang, P.; Chaiyakum, J.; Chamadol, N.; Loapaiboon, V.; Sithithaworn, P.; Elkins, D. B. Cross-sectional study of Opisthorchis viverrini infection and cholangiocarcinoma in communities within a high-risk area in northeast Thailand. Int. J. Cancer 59:505–509; 1994. Streitz, J. M. Jr. Barrett’s esophagus and esophageal cancer. Chest Surg. Clin. N. Am. 4:227–240; 1994. Marrogi, A. J.; Pass, H. I.; Khan, M.; Metheny-Barlow, L. J.; Harris, C. C.; Gerwin, B. I. Human mesothelioma samples overexpress both cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (NOS2): in vitro antiproliferative effects of a COX-2 inhibitor. Cancer Res. 60:3696 –3700; 2000.

[211] Bourdes, V.; Boffetta, P.; Pisani, P. Environmental exposure to asbestos and risk of pleural mesothelioma: review and metaanalysis. Eur. J. Epidemiol. 16:411– 417; 2000. [212] Stevens, R. G.; Moolgavkar, S. H. Estimation of relative risk from vital data: smoking and cancers of the lung and bladder. J. Natl. Cancer Inst. 63:1351–1357; 1979. [213] Liu, C. Y.; Wang, C. H.; Chen, T. C.; Lin, H. C.; Yu, C. T.; Kuo, H. P. Increased level of exhaled nitric oxide and up-regulation of inducible nitric oxide synthase in patients with primary lung cancer. Br. J. Cancer 78:534 –541; 1998. [214] Nakamura, H.; Tsukada, H.; Oya, M.; Onomura, M.; Saito, T.; Fukuda, K.; Kodama, M.; Taniguchi, T.; Tominaga, M.; Hosokawa, M.; Seino, Y. Aminoguanidine has both an antiinflammatory effect on experimental colitis and a proliferative effect on colonic mucosal cells. Scand. J. Gastroenterol. 34: 1117–1122; 1999. [215] Yamaguchi, T.; Yoshida, N.; Ichiishi, E.; Sugimoto, N.; Naito, Y.; Yoshimoto, T. Differing effects of two nitric oxide synthase inhibitors on experimental colitis. Hepatogastroenterology 48: 118 –122; 2001. [216] de Wilt, J. H.; Manusama, E. R.; van Etten, B.; van Tiel, S. T.; Jorna, A. S.; Seynhaeve, A. L.; ten Hagen, T. L.; Eggermont, A. M. Nitric oxide synthase inhibition results in synergistic anti-tumour activity with melphalan and tumour necrosis factor alpha-based isolated limb perfusions. Br. J. Cancer 83:1176 – 1182; 2000. [217] Fukumura, D.; Yuan, F.; Endo, M.; Jain, R. K. Role of nitric oxide in tumor microcirculation. Blood flow, vascular permeability, and leukocyte-endothelial interactions. Am. J. Pathol. 150:713–725; 1997. [218] Jadeski, L. C.; Lala, P. K. Nitric oxide synthase inhibition by N(G)-nitro-L-arginine methyl ester inhibits tumor-induced angiogenesis in mammary tumors. Am. J. Pathol. 155:1381–1390; 1999. [219] Menchen, L. A.; Colon, A. L.; Moro, M. A.; Leza, J. C.; Lizasoain, I.; Menchen, P.; Alvarez, E.; Lorenzo, P. N-(3-(aminomethyl)benzyl)acetamidine, an inducible nitric oxide synthase inhibitor, decreases colonic inflammation induced by trinitrobenzene sulphonic acid in rats. Life Sci. 69:479 – 491; 2001. [220] Armstrong, A. M.; Campbell, G. R.; Gannon, C.; Kirk, S. J.; Gardiner, K. R. Oral administration of inducible nitric oxide synthase inhibitors reduces nitric oxide synthesis but has no effect on the severity of experimental colitis. Scand. J. Gastroenterol. 35:832– 838; 2000. [221] Hosoi, T.; Goto, H.; Arisawa, T.; Niwa, Y.; Okada, N.; Ohmiya, N.; Hayakawa, T. Role of nitric oxide synthase inhibitor in experimental colitis induced by 2,4,6- trinitrobenzene sulphonic acid in rats. Clin. Exp. Pharmacol. Physiol. 28:9 –12; 2001.