lnterleukin-2-Activated Natural Killer Cells Are Active Against Lung Cancer Cells

indicate a more consistent inhibition of monocyte ADCC. Further studies are being undertaken to confirm this observation and to define the chemical characteristics of this putative soluble suppressor factor. We conclude that there is. a defect in the regional expression of ADCC by alveolar macrophages in a majority of patients with small cell cancer of the lung and in some of the patients with other types of primary lung cancer. The defect appears to be, at least in part, the result of a soluble suppressor factor. The reduced ADCC is not a major variable in determining lung cancer survival. However, whether or not reduced ADCC is important in some instances in survival (ie, small cell cancer after complete remission) has not yet been determined. Efforts to enhance pulmonary alveolar macrophage ADCC in primary lung cancer, particularly small cell cancer, by agents such as recombinant immune interferons may offer therapeutic advantages in the treatment of this disease. ACKNOWLEDGEMENT: Studies supported with grants from the Anti-Cancer Foundation of the Universities of South:Australia, and Purposes Fund, RoyalAdelaide Hospital, Adelaide, from the S~ South Australia. REFERENCES

1 2 3 4

5

Nathan CF, Murray H~ Cohn ZA. The macrophage as an effector cell. N Eng) J Med 1980; 303:622-26 Gill PG, Waller CA, MacLennan IC. Relationships between different functional properties of human monocytes. Immunology 1977; 33:873-80 Gill PG, De Young NJ, Kiroff GK, Leppard PI, McLennan G. Monocyte antibody dependent cellular cytotoxicity in splenectomized subjects. J Immunoll984; 132:1244 McLennan G, Gill PG, De Young NJ. Antibody dependent cellular cytotoxicity in blood monocytes and alveolar macrophages in patients with lung cancer. J Nat! Cancer Inst 1985; 75:23-27 Junming LE, Wolf ~ Yip YK, Zongliang C, Hoffman 1: Stevenson HC, et ale Activation of human monocyte cytotoxicity by natural and recombinant immune interferon. J Immunol 1983; 131:2821-25

Interleukln-2-Actlvated Natural Killer cells Are Active Against

Lung Cancer cells·

Bruce Robinson, M.D.; and GeorgeMorstyn, M.D.

N

atural killer (NK) cells are specialized lymphocytes that are able to lyse malignant cells without requiring prior sensitization. They are active against a variety of malignant cell types and are considered to have a role in vivo in defense against malignancy. In humans, tumors of hematologic origin are more sensitive to NK-mediated lysis, whereas many solid tumors are resistant to lysis by NK cells. Lung cancer is the most common type of solid tumor in man. In this study we examined NK activity against lung cancer cells derived from *From the Department of Medicine, University of Western Australia, Queen Elizabeth II Medical Center, Nedlands, and the Clinical Research Unit, Ludwig Institute for Cancer Research, Melbourne, Australia. Reprint Requests: Dr. Robinson, University DeptJ.rtment of Medicine, Queen Elizabeth II Medictll Center, Nedlaiuls 6009,Australia

patients with each of the major types of lung cancer and compared the activity with that against a standard NKsensitive target, the K562 cell. Most previous studies ofNK activity in humans have been restricted to examination of blood NK cell activity, largely because of the relative inaccessibility of functional NK cells from other sites. We also examined the lytic activity of NK cells from lung interstitial cell populations (ie, they were obtained from the lungs of lung cancer patients) against K562 cells and lung cancer cell targets. This was done since the human lung interstitium contains large numbers oflymphocytes, the total number being similar to the total number of lymphocytes present in the blood,' and also because these local lung interstitial lymphocytes, by virtue of their large numbers and on-site location in the lung, are likely to be important components of the lung anti-cancer defense system. Interleukin-2 is an immune mediator that is able to augment NK activity in vitro and in vivo in animals and in vitro in humans. We recently have demonstrated that the activity of NK cells in the alveolar compartment of the normal human lung is augmented when exposed to IL-2 in vivo. I Interleukin-2 also activates human blood lymphocytes to destroy malignant cells that are insensitive to lysis by unactivated NK cells, and recent studies using IL-2 and IL-2-activated lymphocytes in patients with advanced malignancy demonstrated significant tumor lysis." We therefore evaluated the capacity of recombinant human IL-2 to enhance the lytic activity of NK cells from either of these compartments against lung cancer cell targets. MATERIALS AND METHODS

Blood NK cell activity was assayed against the human lung carcinoma lines NCI-H157 (large cell), LICMI07 and NCI-Hl46 (small cell), NCI-H226 (squamous cell) and LICM26 (adeno), and the results were compared with their activity against K562 cells, using a 16-hr 51Cr-release assay. In order to evaluate the level of local lung NK activity against these targets, we extracted interstitial lung lymphocytes from normal areas of lung tissue from lobectomy specimens of 16 lung cancer patients using a slicing/collagenase digestion method, 1 and purified the lymphocytes as previously mentioned. RESULTS

At effector to target ratios (E-l1 up to 50:1, NK activity was very low against each of the lung cancer lines compared with thatfor K562 cells (for NCI-HI57, 10±2%; LICMI07, 12±2%; NCI-HI46, 14± 511>; NCI-H226, 8 ± 511>; and LICM26, 7 ± 311>, compared with K562, 6O±3%; p lysis of each target). Recombinant IL-2 produced a dosedependent augmentation of NK activity against each of the lung cancer cell lines, with doses as low as 0.25 U/m} being effective. The highest level of boosting was seen against H157 cells where NIC activity (E-T ratio of 50:1; IL-2, 250 unitslml) increased from 9 ± 2'11 to 56 ± 7% (p
318

depleted lymphocytes expressed little IL-2-mediated augmentation

of activity against these target cells and (b) most of thi. IL-2mediated augmentation of activity was located in the large granular lymphocyte-enriched fraction of the lymphocyte population. Recombinant IL-2 also augmented the activity of lung NKcellsagainst KS62 and lung cancer cell targets, almost as elTecUvely as with blood NK cells. We currently are evaluating the capacity of IL-2 to augment NK activity against freshly isolated autologouslung cancer

undetectable using current methods but which, by virtue of their small mass, may be susceptible to lysis by immune mechanisms such as IL-2-activated NK cells. It is possible that therapeutic methods such as these maybe most effective when used in conjunction with other existing therapeutic modalities such as chemotherapy or radiotherapy. We are currently evaluating these concepts.

cella.

REFERENCES DISCUSSION

The data presented here suggest a potential therapeutic

role for recombinant human 1L-2 In the treatment of lung cancer. This therapy may involve systemically administered 1L-2 with or without the adoptive transfer of IL-2-activated killer (LAK) cells to patients with advanced. nonresectable, drug-resistant tumors. It may involve the use of 1L-2 as adjuvant therapy in individuals undergoing resection for primary lung cancer, based on the knowledge that many of these individuals have small metastatic deposits that are

1 Holt ~ Robinson S, Reid M, Kees V, Warton A. Dawson ~ et al. Extraction of inflammatory and immune cells from human lung parenchyma: evaluation of an enzymatic digestion procedure. Clfn Exp Immunol 1986;66:188-200 2 Robinson BWS, Pinkston ~ Crystal RG. Natural killer cells are present in the normal human lung but are functionally impotent. J eltn Invest 1984;74:942-50 3 RosenbergSA, LotzeM1: MuulLM. LeitmanS. ChangAE. et all Observationson the systemicadministration of autologous lymphokine-setivated killer cells and recombinant interleuldn-2 to patients with metastaticcancer. N Eng} J Med 1985; 313:1485-92

58sslon 10 Mechanisms of Drug Resistance "....".d b~ Vfctor Ung. M.D.•

Reported bll Cham' Scoggin, M.D., F.C.C.l

£'ncers may be categorized according to drug response. ~ These categories are: 1. Cancers in which responses occur, leading to a normal lifespan. 2. Cancers in which some response occurs, with an increase in survival. 3. Cancers in which there is a response to drug treatment, but increased survival has not been conclusively shown. 4. Cancers in which there is only a marginal response or no response to drug therapy. Lung cancer is an example of the fourth and most difficult category of drug response. Why some cancers are curable with drug treatment and others are not is still not understood. The usual clinicalscenarioofeven the most responsive tumon is the disappearance ofthe tumor (remission), with a future relapse and drug resistance. Cellular and molecular biology hu not given us methods to investigate the phenomenon of tumor drug resistance. 'Iumor-mutant cells have been isolated to allow laboratory analysis of the biochemical buil of cell resistance. M ultidrug resistance denotes a complex cancer cell phenotype of cross-resistance to a wide variety of unrelated drugs. Multldrug resistance (MDR) is a term used to describe cells that havebecome resistant not only to one classof drugs, but also to other agents against which they have not been selected. This phenomenon is of great clinical importance. It means we cannot predict resistance patterns when selecting for resistance to a particular drug. It also means we cannot predict the resistance pattern that will result with the use ofa single drug agent. Finally, MDR cells are more likely to survive and therefore kill the host. The MDR phenotype is characterized by: • From the Ontario Cancer Institute. Universityoflbronto, Toronto.

1. Cross-resistance to unrelated drugs. 2. Decreased accumulation of drugs within the cell. 3. Increased expression of P-glycoprotein. It is this protein that is believed to cause the MDR phenotype. Monoclonal antibodies have been prepared against the membranes from human and hamster MDR and non-MDR cells. This has allowed recognition of a receptor that eorrelates with MDR. P-g1ycoprotein is a 170,000 molecular weight glycoprotein recognized by antibodies to resistant cells. The amount of drug resistance and P-glycoprotein can be correlated. It is believed that P-glycoprotein is present in drug-sensitive cells and increases in amount with resistant cells. Leukemic cells have been transplanted into mice, and the mice then treated with chemotherapy. This results in most mice being cured, but in those who are not cured,.the tumors are resistant to chemotherapy. In such animals, p.g1ycoprotein is increased. In patients with ovariancarcinoma, pleural and ascitic fluid tumor cells showed increuing P-glycoprotein with emergence of MDR. The lame has been seen in other tumors, such assarcomas and lung cancer. Overexpression of p·giycoproteinhas not been seen in normal cells or in pretreatment tumors. The overexpression of p·glycoprotein appears to give a selective advantage to tumor cells. D~ Ling and his associates have cloned the eDNA for P-glycoprotein. M ultidrug resistant cells have been found to have increased amounts ofP-glycoproteingene sequence. It is believed that the p·glycoproteingene sequence represents a multlgene familyof 4-5 genes. This gene has been mapped to the chromosomal location 7q36. DNA transfection experiments have been conducted in which the P-glycoprotein gene has been introduced into nonMOR cells. Recipient cells that then develop MDR have been found to have increased expression of MDR genes. It also appears that only a few members of the gene familyare necessary for the MDR phenotype to be expressed. The normal function of P-glycoprotein is unknown. It probably has a basicfunctionwithin the cell and MDR is only