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ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS

Background: An estimated 162,460 people will die of lung cancer in the United States in 2006, making it the leading cause of cancer deaths. Small cell lung cancer (SCLC) accounts for 20% of all lung cancers and exhibits aggressive behavior with early metastases. Current treatments such as surgery, radiation, and chemotherapy yield 5-year survival rates of only 5-10%, indicating a need for new therapeutic approaches to this deadly cancer. Histone deacetylase inhibitors (HDACIs) represent a new class of anticancer agents. Trichostatin A (TSA), an HDACI, has been shown to inhibit growth in several types of cancer. Until this study, the effects of TSA on SCLC cells have not been reported. Methods: Human DMS53 SCLC cells were treated with TSA (0-400nM). Light microscopy was used to assess changes in cell appearance. Western analysis was performed using antibody against acetylated histone 4 (AH4) to confirm HDAC inhibition. The effect of TSA treatment on cellular growth was measured by MTT assay. Finally, levels of BCL-2, PARP, p21, and p27 proteins were measured to look for induction of cell cycle arrest and/or apoptosis. Results: DMS53 cells treated with TSA underwent dramatic changes in cell appearance. Instead of growing in confluent sheets with ill-defined cell margins, the treated cells assumed round and spindle shapes with distinct cellular borders and gaps between cells. Western analysis demonstrated increased levels of AH4 after TSA treatment, confirming potent HDAC inhibition. Importantly, TSA treatment of DMS53 cells resulted in a marked dose-dependent inhibition of proliferation. Elevated p21 and p27 protein levels indicated cell cycle arrest mediated growth inhibition. Furthermore, decreased BCL-2 and increased PARP cleavage demonstrated the induction of apoptosis. Conclusions: TSA causes morphologic differentiation in SCLC cells. Moreover, TSA treatment leads to a dose-dependent inhibition of cellular proliferation by inducing cell cycle arrest and subsequent apoptosis. These findings suggest that TSA and other HDACIs may represent a new, exciting potential therapy for patients with SCLC.

vascular calcifications. The presence of vascular calcifications for both groups according to age stratification is presented in table 1. The women with CAD had a significant increase in mammographic calcifications when compared with women undergoing routine screening at every age group as demonstrated in Figure 1. (CMH test stratifying by age group, p⬍0.001). Conclusions: Identification of vascular calcifications on screening mammogram is routinely reported but their significance has not been determined. This study identified the presence of benign vascular calcifications on screening mammography significantly increases with age. This age related increase was significantly higher in the group with CAD. This study indicates women with vascular calcifications seen on screening mammography may be at risk for CAD. Further prospective studies are underway at our institution to further identify the association of CAD, PVD, diabetes and the presence of mammographic vascular calcifications. Key Words: coronary artery disease, screening mammography, vascular calcifications.

table 1: Vascular calcifications according to age and group Age Screening Calc Calc⫹ Total WithCAD Calc Calc ⫹ Total

23-41 42-44 45-49 50-52 53-56- 57-59 60-63 64-67 68-72 73-77 78-71 82-93 total

44 1 45

45 0 45

88 1 89

82 2 84

90 8 98

65 3 68

49 12 61

42 21 63

38 31 69

30 30 60

17 18 35

9 19 28

599 146 745

3 1 4

8 1 9

21 6 27

16 5 21

31 14 45

17 10 27

35 20 55

21 25 46

27 43 70

14 29 43

5 19 24

4 20 24

202 193 395

P⬍.0001 for both groups

145. MAMMOGRAPHY AS A SCREENING TOOL FOR CORONARY ARTERY DISEASE. P. S. Dale, C. Mascarenhas, M. Richards, G. Mackie; University of Missouri School of Medicine, Columbia, MO Background: Heart disease and cancer are the leading causes of death among women. Currently a widespread inexpensive screening test is not available for coronary artery disease (CAD). Prior studies have indicated benign vascular calcifications identified on routine screening mammography are more prevalent in women with peripheral vascular disease, diabetes and CAD. The purpose of this study was to identify a significant association between vascular calcifications seen on screening mammography and CAD. If such an association exists then screening mammography may identify women at risk for CAD. Methods: To determine the incidence of vascular calcifications in our general screening population we prospectively evaluated consecutive routine screening mammograms for the presence of benign vascular calcifications. Utilizing a computerized data base maintained by the Division of Cardiology we identified a population of women with CAD who had undergone screening mammography at our institution. All women in the screening and CAD groups were evaluated according to age group and the presence of vascular calcifications. Statistical analysis utilizing the Cochran-mantel-Haenszel (CMH) test and Cochran-Armitage (CA) test for trend was performed to determine the association of CAD, mammographic vascular calcifications and age. Results: Prospective evaluation of 745 women undergoing consecutive routine screening mammography identified 146 (20%) with benign vascular calcifications. Utilizing our CAD computerized database we identified 395 women with CAD who had undergone screening mammography at out institution. On review 193 (49%) of these women had benign

146. TARGETING CAP-DEPENDENT MRNA TRANSLATIONAL CONTROL PATHWAYS IN ESOPHAGEAL CANCER. O. A. Issaenko, A. K. Arrington, G. Dahal, P. B. Bitterman, M. A. Maddaus, P. S. Dahlberg; University of Minnesota, Minneapolis, MN Background: A broad range of epithelial cancers display aberrant activation of the AKT/mTOR/eIF4E cap-dependent mRNA translation pathway regulating cell growth, proliferation and apoptosis. The purpose of these experiments was to test the hypothesis that inhibition of the pathway in esophageal adenocarcinoma (EAC) cells alters their malignant phenotype. Methods: In 4 EAC cell lines (OE19, OE33, Bic-1, Seg-1) we targeted mTOR using rapamycin or eIF4E (the major positive regulator of cap-dependent protein synthesis) by

ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS introducing wild type or a constitutively active form (TTAA) of 4EBP1 (the negative regulator of eIF4E). Cells were assayed for changes in proliferation (MTT assay), clonogenic growth, and cell cycle (FACS). Changes in the level of cap-dependent mRNA translation were measured using a bicistronic luciferase reporter plasmid where Renilla luciferase is translated in a cap-dependent and firefly luciferase in a cap-independent (IRES) manner. Results: Rapamycin was a potent inhibitor of proliferation in all cell lines tested with IC50s in the nanomolar range. Treatment was associated with a reduction in cap-dependent mRNA translation in all cases (data not shown). Introduction into cells of 4EBP1, a downstream target of mTOR, inhibited proliferation and clonogenic growth of OE19 and OE33 but not of Bic-1 nor Seg-1. The effect was associated with cell cycle arrest, the induction of apoptosis, and with a reduction in the fraction of cap-dependent protein synthesis (See Figure for OE33). Conclusions: Targeting the activity of the cap-dependent mRNA translational machinery at the level of mTOR is an effective strategy for altering the malignant phenotype of EAC cell lines in vitro. In at least some cell lines the anti-neoplastic effect is likely to be mediated by effects on targets of Mtor other than 4EBP1.

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tial infarct (41.9 ⫾ 4.3% vs 9.4 ⫾ 4.9%, *p ⬍.004). IKK␤ inhibition significantly reduced infarct size (21.9 ⫾ 5.9%, **p⬍0.02). There was no difference between sham and IKK␤ groups. After 2 hours of reperfusion, hearts were procured for biomolecular analysis. Interestingly, there was no difference in the p65 NF-␬B nuclear/ cytoplasmic ratios between all groups. Furthermore, IKK␤ inhibition appeared to increase cytoplasmic content of p65. Similarly, compared to control ligation mice, IKK␤ inhibition also increased the relative expression of the myocardial early response genes BNP and cfos, as well as p65. Conclusion: In this murine infarct model, IKK␤ inhibition significantly reduced the size of myocardial infarction. This potent upstream inhibitor of NF-␬B also resulted in increased expression of cytoplasmic p65 and early response genes. This paradox could be explained, in part, by NF-␬B-I␬B autoregulation, timing of our molecular analysis, or alternative pathways. Although its exact mechanism remains to be determined, proximal blockade of the NF-␬B signaling pathway with IKK inhibition may prove useful to limit myocardial ischemia-reperfusion.

148. WITHDRAWN 147. INHIBITORY KAPPA B KINASE (IKK) INHIBITION ATTENUATES INFARCT SIZE IN A MURINE MODEL OF MYOCARDIAL ISCHEMIA-REPERFUSION. N. C. Moss, W. E. Stansfield, M. Rojas, M. Willis, R. Tang, C. H. Selzman; University of North Carolina, Chapel Hill, NC Introduction: Despite improvements in protection, myocardial ischemia/reperfusion remains an important cause of cardiac dysfunction. Multiple strategies exist experimentally; few are clinically accessible. Nuclear factor kappa-B (NF-␬B) is a transcription factor central to the inflammatory response and is implicated in reperfusion injury. Its activation relies on the phosphorylation of its inhibitor, I␬B, through its upstream kinase complex (IKK). IKK consist of two catalytic subunits, IKK␣ and IKK␤, and a regulatory subunit, IKK␥. IKK␤ is essential for regulating the inflammatory effects of NF-␬B. To date, no studies have examined the influence of IKK inhibition of NF-␬B on myocardial ischemia and reperfusion. Methods: Under ketamine/xylazine anesthesia, 15 C57BL6 mice had thorocotomy and exposure of the left anterior descending artery (LAD). Sham animals had a suture placed under the LAD; control mice had temporary ligation for 30 minutes followed by either 2 or 24 hours of reperfusion; IKK␤ mice were treated with the inhibitor (i.p) 30 minutes prior to similar ligation and release. After 24 hours, hearts were excised and examined for viability by staining with TTC. Areas of infarct were quantified using an NIH image analysis program. Western blot was performed to measure the NF-␬B nuclear translocation of its key subunit, p65. Early myocardial response gene expression was measured by realtime PCR. Results: Compared to sham animals, LAD occlusion in control mice resulted in a substan-

149. WITHDRAWN 150. WITHDRAWN

CLINICAL TRIALS/OUTCOMES II: CLINICAL CONSIDERATIONS 151. SURVIVAL FOLLOWING LIVER RESECTION FOR METASTATIC COLORECTAL CARCINOMA IN A LARGE POPULATION. S. A. Shah 1, R. Bromberg 2, A. Coates 3, M. Simunovic 3, S. Gallinger 2; 1University of Massachusetts, Worcester, MA, 2University of Toronto, Toronto, ON, Canada, 3Hamilton Health Sciences, Hamilton, ON, Canada Previous reports of liver resection for metastatic colon cancer (CRC) are typically from single-centers and thus may not account for selection or referral bias. We measured long-term survival following liver resection for CRC in the province of Ontario, Canada (population 12 million). Methods: The Ontario Cancer Registry is an administrative database that links all hospital records, pathology reports, and vital statistics for patients with a diagnosis of cancer. We used the Registry to identify patients who underwent liver resection for metastatic CRC in calendar years 19962004. Pathology reports were directly reviewed to obtain variables including type of resection, number and size of lesions, tumor grade and margin status. Other variables available included patient (age, gender, original CRC TNM stage, and timing of liver