Aurelia M. C. Koros

Substance P analogues function as bombesin receptor antagonists and inhibit small cell lung cancer clonal growth

Human small cell lung cancer (SCLC) produces and secretes BN/GRP (bombesin/gastrin releasing peptide). Because BN stimulates the growth of SCLC cells and these cells have receptors for BN-like peptides, it is important to define agents which disrupt this self-promoting autocrine growth cycle. Here, substance P analogues were evaluated as BN receptor antagonists using SCLC cell lines. (D-Arg1, D-Pro2, D-Trp7.9, Leu11) substance P [(APTTL)SP] was one of the more potent analogues tested in inhibiting BN-like peptide receptor binding with an IC50 value of 1 microM. Micromolar concentrations of (APTTL)SP antagonized BN receptor mediated elevation of cytosolic Ca2+ levels and decreased the colony formation in soft agarose. These data suggest that SP analogues function as SCLC BN receptor antagonists and may be useful in disrupting the autocrine growth function of BN-like peptides.

JLP5B9: new monoclonal antibody against polysialylated neural cell adhesion molecule is of value in phenotyping lung cancer

Non-small-cell lung cancer (NSCLC) is currently one of the most prevalent malignant tumors. It displays a wide variety of phenotypes which includes neuroendocrine markers commonly found on small-cell lung cancers (SCLC) such as the neural cell adhesion molecule (NCAM) and in particular its highly polysialylated isoform, embryonic NCAM (eNCAM). NSCLC with neuroendocrine differentiation may represent a subset of tumors whose cells have a more aggressive biological behavior. A tumor marker that distinguishes this latter sub-type could be of clinical relevance. Accordingly, we have raised a monoclonal antibody of the IgM type (JLP5B9) directed against capsular polysaccharides of N. meningitidis B which bears polysialic acid groups. We have demonstrated that JLP5B9 recognizes eNCAM with high affinity and that it is specifically directed against the polysialic acid moieties of NCAM. JLP5B9 was also found to react with human SCLC, NSCLC and neuroblastoma cell lines. We then used JLP5B9 as a specific probe for the detection of tissue eNCAM and found that it was expressed on up to 20% of tumor cells obtained from 5 out of 13 patients with NSCLC. This mAb deserves further investigation to evaluate its potential as a tool for serodiagnosis of lung cancer.

Immunoregulatory Consequences of Vitamin Deficiencies on Background Plaque-Forming Cells in Rats

Summary Background hemolytic plaque-forming cells (PFC) directed against three erythrocyte targets were measured in rats with three different, specific vitamin deficiencies: riboflavin, pyridoxine, and pantothenic acid, as well as in control rats. The numbers of background PFC were found to be elevated in all three vitamin-deficiency states compared with controls, whereas earlier studies showed that postimmunization PFC were markedly depressed in those deficiencies tested. The significance of these findings is discussed in terms of a possible loss of suppressor cells. This work was supported by grants from the U.S. National Institutes of Health (1 RO1 HD 08549-01) to A. E. Axelrod, and the Health Research and Services Foundation (R-62) to A. Koros. We thank Dr. T. T. Hayashi, Dr. T. J. Gill, III, and Dr. G. Werner for their special help in this project. We also thank Helen Baginski for technical assistance, and Lorraine Repasky for preparation of the manuscript.

Chapter 9 Monoclonal antibodies directed against small cell carcinomas define by flow cytometry phenotypic differences among small cell and non-small cell carcinomas, neuroblastomas, and lymphoblastoid cell line

Abstract Indirect immunofluorescence and flow cytometry were used to determine reactivity of workshop antibodies with a large panel of human cultured cell lines which included small cell lung carcinoma (SCLC) “classic”, and “variant”; and non-small cell lung carcinomas (NSCLC). Other cell lines were SHP-77 1 (an unusual “oat cell” large cell variant which has the morphology of a “variant”, but biochemical properties of a “classic” SCLC). Also studied were 2 neuroblastoma lines, 2 colon carcinoma and 5 lymphoblastoid lines. Three morphologically similar “classic” SCLC were phenotypically different in reactivity with workshop antibodies, suggesting that testing with such a panel is a new means to classify SCLC. The “classic” lines also differed in intensity of labelling with some of the reactive monoclonals, indicating differences in density of surface markers. Xenografts of human tumour lines grown in nude mice reacted very strongly with (FAB 1 ) 2 anti-mouse fragments, suggesting that such xenografts have nude mouse immunoglobulins on their surface. Evidence is presented that some monoclonals may react with tumour cells via Fc receptors NCSCLC, colon carcinoma, and lymphoblastoid lines also react with some workshop antibodies.

Small cell lung cancer antigen expression differs on ‘classic’ and ‘variant’ SCLC and carcinoid cells

Abstract The panel of 98 monoclonal antibodies (MOABS), (mouse or rat) provided by the Second International Workshop on Small Cell Lung Cancer Antigens was tested by indirect immunofluorescence and flow cytometry using prototype cell lines [NCI-H69 (SCLC ‘classic’), NCI-N417 (SCLC ‘variant’), NCI-H727 (carcinoid) [A.F. Gazdar et al. (1985, 1988)] peripheral blood lymphocytes (PBL), and sea urchin coelomocytes [Koros, A.M.C. et al. (1987, 1988, 1989).] All cells had some reactivity with some of the MOABS. There is however, differential expression of antigens amongst the prototype cell lines, which may provide a useful method for phenotyping human lung cancers. More MOABS react with the SCLC ‘classic’ NCI-H69 than with any of the other cell types (MOABS, 5, 12, 16, 18, 21, 28, 31, 34, 36, 41, 45, 47, 48, 53, 56, 58, 69, 70, 71, 79, 87, 91). MOABS 45-49 seem most useful in distinguishing between SCLC and carcinoid cultured cell lines. Those MOABS which do not react with normal PBL (MOABS 3, 5 and 12 especially) should be tested further for possible utility as therapeutic agents in patients whose tumours have escaped conventional therapy. In contrast to our earlier observations of neuroendocrine markers (CD56, CD57) on SCLC, neuroendocrine cells, human natural killer cells, and sea urchin coelomocytes, few (14/50) antigens identified by the present panel appear to be evolutionarily conserved.