Charles C. Cate

Bombesin production by human small cell carcinoma of the lung

A series of continuous cell lines of human small cell carcinoma of the lung (SCCL) have been evaluated for the production of bombesin (BN). In early established cultures BN was detected in the medium of 9 out of 11 cell lines and in 6 out of 7 cell homogenates examined. Levels in the medium were frequently higher in cultures of later passages compared to earlier passages of the same line and low levels developed in the two previously negative cell lines. Plasma concentrations were greater than 80 pmol/l in 2 out of 27 (7%) randomly selected patients with SCCL. A culture (DMS 406) established from the tumor of a patient with the highest plasma level (1240 pmol/l) was the highest producer in vitro. The results indicate that BN, which has been demonstrated immunocytochemically to be present in normal bronchial mucosal cells, is frequently produced by SCCL in vitro but elevated plasma levels are infrequently found in patients with this neoplasm.

Cytogenetics of small cell carcinoma of the lung

Nineteen cell lines derived from various malignant tissues of 15 patients with small cell carcinoma of the lung (SCCL) have been studied. The results showed heterogeneity in all cell lines, with no one consistent abnormality among them. Cell lines from 11 of the patients had minute and double minute chromosomes, and cell lines from 2 patients had abnormally banding regions, designated as ABRs, as distinguished from homogeneously staining regions (HSRs). The latter 2 and several of the former cell lines were derived from specimens taken before the patients were placed on therapy. All but 2 of the cell lines had a constant marker load, consisting of 24%-35% of the complement. Some markers remained stable through months and years of culture life, while other markers came and went. Chromosomes #1, #6 and #11 were most frequently involved in marker formation in the cell lines, and these were compared to similar markers in direct bone marrow preparations. Chromosome #1 markers were of variable structure, whereas #6 and #11 most often took the form of 6q- and 11p+ markers, with breakpoints most frequently at 6q23-25 and 11p11-12. A 3p- marker was found in a minority of cell lines. All of these markers were also found in direct marrow preparations from some patients with SCCL. Nonmonoclonal tumors arose from inoculation of bimodal cell lines into nude mice, but population selection by undetermined mechanism was evident. Cytogenetic parameters showed no positive correlation with hormone production by these cell lines.

Bombesin and calcitonin secretion by pulmonary carcinoma is modulated by cholinergic receptors

Three established cell lines derived from human small cell carcinoma of the lung, and known to produce significant amounts of peptide hormones were used to evaluate the regulation of hormone secretion by cholinergic agonists. In two of the cell lines (DMS 53, DMS 153) acetylcholine chloride, bethanechol chloride, and carbamylcholine at the concentrations of 10(-3)M to 10(-5)M stimulated secretion of bombesin and calcitonin as measured by RIA. The third cell line, DMS 406, was not significantly stimulated. Inhibition of induced stimulation by the cholinergic antagonist atropine, but not hexamethonium, indicated the presence of muscarinic rather than the nicotinic type of cholinergic receptors on the stimulatable cells. These receptors appear to mediate hormone secretion comparably to normal endocrine cells.

Immunocytochemical staining of cytocentrifuge prepared cultured cells: nonspecific staining and its elimination

SummaryIn an attempt to localize hormones in cytocentrifuge-prepared cultured cells of small cell carcinoma of the lung (SCCL), various modifications of the immunoperoxidase (PAP) procedure (Sternberger, 1979) were tested. When using glutaraldehyde, formaldehyde, orp-benzoquinone fixation (Pearse & Polak, 1975) and rabbit antibodies in primary or bridging steps of the PAP procedure, nonspecific staining (false positives) could be elicited with the majority of rabbit antibodies tested, but not with antibodies from other animal sources. This problem could be eliminated by fixation of cells either with formalin-acetone (Masonet al., 1975) or, when using antibodies from a source other than rabbit, glutaraldehyde. It was not possible to localize ACTH in DMS-79, a human SCCL line known to produce this hormone. However, calcitonin was localized in the calcitonin-producing SCCL line DMS-53. Failure to localize ACTH in DMS-79 may be due to the lower levels of this hormone in DMS-79, as compared to the levels of calcitonin in DMS-53. This study emphasizes the importance of proper controls before concluding successful localization in a given immunocytochemical preparation of cultured cells.

Morphological Growth Characteristics and Hormone Secretion of Small Cell Carcinoma of the Lung In Vitro

Since 1974 a group at Dartmouth Medical School has been actively engaged in in vitro studies of small cell carcinoma of the lung (SCCL), utilizing tumors which have been obtained from patients with a known diagnosis of this disease. Continuous cell lines have been established from biopsy or autopsy specimens from patients with a known pathologic or cytologic diagnosis of SCCL.

Regulation of Hormone Production in Small Cell Carcinoma of the Lung

Patients with pulmonary carcinoma frequently have elevated levels of one or more circulating tumor-produced hormones. This is particularly characteristic of small cell carcinoma of the lung (SCCL), where an increased frequency of hormone production is seen more commonly than in other types of lung cancer. The most frequently elevated hormones in such patients are calcitonin (CT), ACTH and neurophysins (Sorenson et al. 1984a). In addition to the noteworthy frequency of hormone production by tumors in these patients, there is also a wide variety of hormones produced by individual SCCL tumors. The reasons for the common occurrence and the great variety of hormones produced by SCCL are unknown, as are the molecular mechanisms involved.

In Vitro Isolation of Malignant Cells from Small Cell Carcinomas

Publisher Summary This chapter discusses the in vitro isolation of malignant cells from small cell carcinomas. It describes a study involving the assessment of the in vivo growth potential of SCCL cells after adaptation to in vitro culture to determine whether their malignant potential is retained. The tumor growth in nude athymic mice is thought to be the best measurement of such potential. The growth rates of tumors initiated from cultured SCCL cells in nude mice were evaluated to provide an in vivo model system to study factors affecting tumor cell growth. It was found that the tumor incidence was significantly greater in males than in females. This may be to the result of a difference in immune response, as the female mice demonstrated a twofold greater cell-mediated immune response to sheep red blood cells than male mice. The alterations in phenotype involve changes in the level of differentiation. The most important of these characteristics is a limited growth potential which, if present in the SCCL cells in culture, would suggest the development of a differentiated cell with a decreased capacity to divide.