Chloramphenicol: effects on mouse myeloma cells in tissue culture.

Within 36 hours of being administered, chloramphenicol (50 micrograms per milliliter) inhibits by 50 percent the rate of protein synthesis in mouse myeloma cells grown in suspension culture. Although there is a decrease in the amount of globulin synthesized, the rate of synthesis per cell is unchanged; the observed decrease is traced to the inhibition of cell proliferation caused by chloramphenicol.

Calcium spike electrogenesis and other electrical activity in continuously cultured small cell carcinoma of the lung.

Spike electrogenesis, local depolarizing and hyperpolarizing responses, spontaneous rhythmic firing, and alternating resting potentials were measured in cells from a continuously cultured small cell carcinoma of the lung. Spike generation was blocked by MnCl2. In view of this evidence for calcium-spike electrogenesis and previous evidence of secretory activity in these cells, this cell line (DMS 53) can provide a model for the study of excitation-secretion behavior in human neoplastic cells.

Monoclonal antibodies reactive with small cell carcinoma of the lung.

Murine monoclonal antibodies (MoAb) reactive with antigens associated with small cell carcinoma of the lung (SCCL) were prepared and partially characterized. Four were selected for further study on the basis of their lack of reactivity with normal leukocytes and erythrocytes. These MoAb, designated SCCL-41, SCCL-114, SCCL-124, and SCCL-175, are all IgM immunoglobulins. The binding of these MoAb to patient-derived SCCL tumor cells, SCCL cell lines, and non-SCCL cell lines was studied by indirect immunofluorescence and flow cytometry. Considerable heterogeneity in the expression of these cell surface antigens was noted among both the patient-derived tumor cells and the SCCL cell lines. One of the MoAb, SCCL-175, reacted with 7 of 7 patient-derived tumor cell samples and 9 of 10 SCCL cell lines. None of the antigens defined by these MoAb were expressed on non-SCCL lung tumor cell lines. SCCL-175 reacted with cells from both a choriocarcinoma and a colon carcinoma cell line, whereas the other 3 MoAb were unreactive with these and several other tumor cell lines. These MoAb may be useful in the diagnosis and subclassification of SCCL tumors.

Karyotypic evolution associated with loss of tumorigenicity.

A reproducible association between loss of tumorigenicity and specific karyotypic changes was described in cell culture lines SLU-5 and DMS-402 established from mouse plasmacytoma MOPC-21 carried in BALB/c mice. The defect in chromosome no. 15, which has been specifically associated with mouse myelomas, was neither corrected nor eliminated in the karyotypic evolution that occurred simultaneously and progressively with the grandual loss of oncogenicity.

Karyotype, marker formation, and oncogenicity in mouse plasmacytomas.

Two common chromosome markers in the 2 plasmacytomas previously examined by Giemsa banding were consistently present in the mouse plasmacytoma X-5563, a transplantable hypertetraploid tumor of spontaneous origin in C3H mice. The 2 markers were found in both induced and spontaneous tumors and in either BALB/c or C3H mice. The derived cell line had 17 fewer chromosomes than the X-5563 tumor and was oncogenic, and its modal karyotype was identical to that of the tumor transmitted by the inoculation of the cell line. The homogeneity of a slight karyotypic modification in a second tumor suggested a possible clonal origin of that tumor. The high frequency of centric fusions between homologues and the structure of certain markers suggests that homologue association may precede marker formation. We proposed a second mechanism of marker formation, selective regional elongation, to account for the larger number of markers with proximal or distal elongations without evidence of translocation and for the observed alterations in length and banding pattern of markers after growth in vitro. Comparison of MOPC-21, MOPC-315, and X-5563 tumors showed preferential involvement of certain chromosomes in marker formation, an inferred association of the 2 common markers with an early stage in the origin of the 3 plasmacytomas, and consistent loss of an X chromosome. Loss of oncogenicity in cell lines was associated with a number of karyotypic changes, but did not require the loss of the characteristic markers or additional copies of a specific normal chromosome.

A specific chromosome breakpoint associated with mouse plasmacytomas.

The chromosomes of uncultured cells of the near-diploid mouse plasmacytoma MOPC-31C were studied. The modal number of chromosomes was 44. The tumor lacked two marker chromosomes, reciprocal translocation [rcp t(12; 15)], that in previous studies were found to be common to 3 other uncultured myelomas and 1 cultured mouse myeloma. Through the formation of two markers, rcp t(6; 15), unique to this tumor, however, the tumor shared with other tumors and their specific markers a common breakpoint in chromosome "15 at band D3/E. This breakpoint has been found in all mouse plasmacytomas examined with banding thus far and is considered of possible importance in the development of this tumor.

Isolation and characterization of a hormone-producing cell line from human small cell anaplastic carcinoma of the lung.

A continuous cell culture line was established from a bone marrow metastasis of small cell anaplastic carcinoma of the lung. The cultures were characterized by light and electron microscopy, and an unusual concentric arrangement of cells was observed, both in sectioned material from the patient's tumor and from the cell cultures. The cells had two types of specialized cell junctions and contained secretory-like granules of the type described in neuroendocrine cells. Lactic dehydrogenase isozyme patterns were the same as those observed in normal human serum, and the karyotype revealed the presence of several marker chromosomes. Vasopressin was present in the cells and secreted into the culture medium in the absence of neurophysin, as shown by the immunoperoxidase technique and radioimmunoassay. Oxytocin was also absent from cells.

Biosynthesis of procalcitonin in small cell carcinoma of the lung.

Immunoreactive calcitonin (CT) secreted by DMS 53, a cell line derived from human small cell carcinoma of the lung, consists almost entirely of molecular species larger than the mature hormone (Mr 3,420). Messenger RNA isolated from DMS 53 cells and nude mouse tumors was translated in wheat germ systems, and the products were precipitated with CT-specific antisera. Analyses of the translation products by electrophoresis on 15% polyacrylamide-sodium dodecyl sulfate gels indicated synthesis of a Mr 16,500 preprohormone that was reduced to Mr 14,500 by cotranslation with microsomal membranes. Immunoprecipitation of CT from media from pulse-labeled cultures revealed two major products (Mr 16,500 and Mr 14,500) and up to three minor secreted polypeptides (Mr 9,400, 8,400, and 6,800). Intracellular CT from cell homogenates appeared almost entirely as a single major product (Mr 14,500) and possibly 3-4 minor components (Mr 16,500; 9,200, 8,400, and 6,800). No glycosylated forms of CT were demonstrable by lectin binding methods or labeling attempts with tritiated sugars. The presence of multiple CT species in DMS 53 cells suggests significant post-translational processing of the larger precursor molecules and the accumulation and secretion by small cell carcinoma of the lung of several intermediate immunoreactive forms via a glycosylation-independent secretory pathway.

Expression of myeloid and major histocompatibility antigens on small cell carcinoma of the lung cell lines analyzed by cytofluorography: modulation by gamma-interferon.

Recent reports have described the expression of myeloid cell surface antigens on cells of small cell carcinoma of the lung (SCCL). In order to confirm and extend these findings, we have examined by cytofluorography a large panel of well-characterized cell lines derived from SCCL tumors for the expression of several myeloid cell-associated antigens, some of which were not examined in previous reports. In addition, we have studied the expression of Classes I and II HLA antigens on these SCCL cell lines. Finally, we examined the effect of gamma-interferon on the expression of several cell surface markers and on proliferation of SCCL cells. We have found that several SCCL cell lines expressed a Mr 55,000 polypeptide antigen, My23, previously found only on monocytes and monocytic leukemia cells. In addition, the cell lines studied expressed another antigen, defined by monoclonal antibody AML-1-99, which is associated with monocytes and hematopoietic stem cells. We confirmed previous studies that the Leu-7 antigenic determinant is expressed on SCCL cells but observed only minimal or absent binding of monoclonal antibody OKM1 to most cell lines. Class I HLA antigens were present on eight of nine lines examined while Class II HLA was expressed on three of nine lines. Gamma-Interferon decreased the proliferative rate of all lines examined. However, this lymphokine was capable of inducing Class I HLA on several lines. The effect of gamma-interferon on other cell surface antigens was variable. These studies confirm that some myeloid cell-associated antigens are expressed on cultured SCCL lines and, additionally, show that their expression can be modulated by immune interferon. Determining the significance of finding myeloid cell-associated antigens on SCCL cells will require further study.

Abnormalities in structure and expression of the retinoblastoma gene in small cell lung cancer cell lines and xenografts in nude mice.

The putative retinoblastoma gene (Rb) is a tumor suppressor gene which is believed to cause retinoblastomas when both alleles are inactivated, leading to lack of the encoded Mr 110,000-116,000 phosphoprotein. Inactivation of the Rb gene has also been found in several other tumor types, including small cell lung cancer (SCLC). Absence of the 4.7 kilobase mRNA has been found to be frequent in SCLC, and it has been reported that the Rb Mr 110,000-116,000 protein product is always absent, even in tumors expressing Rb mRNA. Using Western blotting technique with a monoclonal antibody directed against the Rb protein, we investigated the expression of the Mr 110,000-116,000 Rb protein in SCLC tumors grown as xenografts in nude mice and/or as cell lines. Rb messenger RNA expression was determined by Northern blotting, and gross structural gene alterations were investigated by Southern blotting. Tumors established from 23 patients were studied. Seven of the tumors did not express Rb protein, whereas expression was detectable in 13. Three tumors were not investigated for protein expression. Only two tumors expressed Rb mRNA without detectable Rb protein expression. Gross DNA alterations were found in four tumors, of which only one expressed Rb mRNA. Our results demonstrated frequent absence of Rb mRNA and protein in SCLC, but apparently normal Rb mRNA and protein were both expressed in more than one-half of the tumors.

Calcitonin as an indicator of the response of human small cell carcinoma of the lung cells to drugs and radiation.

A calcitonin (CT)-producing cell line (DMS53) established from human small cell carcinoma of the lung was grown as three-dimensional multicellular spheroids in spinner culture or on agar in multiwells, and as tumors in nude (athymic) mice. CT release into the media was directly proportional to spheroid volume. The response of these cells following exposures to X-irradiation, Adriamycin, or diazoacetylcholine iodide was assessed by monitoring levels of CT released into the media by individual spheroids. Levels of CT in the blood of nude mice bearing DMS53 xenografts were directly proportional to tumor volume and decreased proportionally with tumor response to X-irradiation and cisplatin treatment. These results suggest that the DMS53 spheroid and xenograft models may be useful systems to monitor responses to therapy utilizing CT as an indicator of tumor burden.

In vitro and in vivo alterations of long-term murine plasmacytoma cultures.

Mouse myeloma cell line (SLU-5) that has undergone lengthy propagation in vitro and become nononcogenic was compared with an earlier oncogenic passage of cells. Immunogenicity of cells cultured for various periods of time was compared with that of the original tumor (MOPC-21). The nononcogenic cells were most immunogenic. Cells that were nononcogenic in normal mice produced tumors in nonlethally irradiated mice. Clones isolated from oncogenic and nononcogenic populations varied widely with respect to ability to produce tumors in mice and to specific globulin production.

Ectopic production of somatostatin-like immuno- and bioactivity by cultured human pulmonary small cell carcinoma.

Eleven continuous cultures of human pulmonary small cell carcinoma cells were examined, and eight were shown to secrete quantities of somatostatin-like immunoreactivity (SRIF-LI) ranging from 0.07-27 ng/ml culture medium/4 days, SRIF-LI was also found in a 2-N acetic acid extract of one of three human pulmonary small cell carcinomas obtained at autopsy as well as in the extract of a solid tumor resulting from inoculation of nude, athymic mice with SRIF-LI-producing, cultured small cell carcinoma cells. The SRIF-LI produced by one continuous cell line, DMS 53, was characterized in terms of its immunological, chromatographic, and biological properties. SRIF-LI from DMS 53 culture media and lysed cells was heat stable and exhibited parallel displacement to synthetic SRIF standard in a double antibody RIA. DMS 53 SRIF-LI was quantitatively retained on an immunoaffinity column of sheep anti-SRIF-Sepharose 4B under neutral conditions and could be eluted with 2 N acetic acid. Gel filtration chromatography of immunoaffinity-purified SRIF-LI revealed multiple molecular weight forms, the largest of which had an apparent molecular weight of 10,000-12,000 daltons and may represent a precursor form. This high molecular weight SRIF-LI form was resistant to exposure to denaturing conditions (8 M urea or 4 M urea plus 0.5% mercaptoethanol), suggesting the absence of noncovalent and/or disulfide linkages. A low molecular weight form coeluted with synthetic SRIF. Additional evidence for the identity of this form with the tetradecapeptide was provided by highly specific reverse phase high performance liquid chromatography. The rate of degradation of high molecular weight SRIF-LI by the cultures was markedly reduced in comparison to that of the SRIF monomer, resulting in a preferential accumulation of high molecular weight SRIF-LI in 4-day culture medium. Bioactivity of DMS 53 SRIF-LI was assessed in 4-day primary monolayer cultures of rat adenohypophyseal cells where 10(-10)-10(-9) M synthetic SRIF elicited a linear log-dose suppression of 5 X 10(-4) M synthetic SRIF elicited a linear log-dose suppression of 5 X 10(-4) M dibutyryl cAMP-stimulated rat GH release. Immunoaffinity-purified SRIF-LI from DMS 53 lysed cells and 1-h serum-free incubation medium, which consisted predominantly of monomeric SRIF, was equipotent to synthetic SRIF, SRIF-LI from 4-day culture medium consisted mostly of the high molecular weight form and exhibited a reduced bioassay potency ratio relative to synthetic SRIF of 0.73 (95% confidence limits, 0.99-0.53). Chromatographically purified high molecular weight SRIF-LI had significant bioactivity with a bioassay to immunoassay ratio of 0.19 (95% confidence limits, 0.33-0.09). The demonstration of ectopic SRIF, production by human pulmonary small cell carcinoma is consistent with the proposed derivation of this tumor from a cell type in the amine precursor uptake and decarboxylation cell series.

Ectopic production of high molecular weight calcitonin and corticotropin by human small cell carcinoma cells in tissue culture: evidence for separate precursors.

The DMS-79 continuous line of human small cell lung carcinoma cells, which produces immunoreactive (IR)-corticotropin (ACTH), -lipotropin (LPH), and -beta-endorphin (beta END), was found to produce IR-calcitonin (CT). Two major high molecular weight (HMW) forms of IR-CT were observed after gel exclusion chromatography under denaturing conditions (mol wt. approximately 7,000 and approximately 14,000), as well as a minor HMW IR-CT component (mol. wt. approximately 70,000). None of these IR-CT materials was extracted from DMS-79 medium by affinity chromatography using an ACTH antibody covalently bound to agarose. These results demonstrate ectopic production of HMW forms of CT and ACTH/LPH/beta END by human lung tumor cells in tissue culture, but do not support the existence of a common CT/ACTH/LPH/beta END precursor molecule.

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 medullary carcinoma of the thyroid.

Medullary carcinoma of the thyroid (MCT) is a dominantly inheritable neoplasm derived from intrathyroid C cells. The cytogenetics of this tumor has been only sparsely and indirectly studied previously. This article describes the chromosomes of primary MCT tumor tissue cultured with colcemid for 48 hr, metastatic tumor in lymph node cultured for 7 days from the same patient, and of primary tumor tissue cultured for 3 weeks from a second patient. The modal numbers were 42-44 in all 3 specimens. Karyotypes from the metastastic tumor were similar to those of the primary tumor. Karyotypes of the two primary tumors, however, differed from each other, having in common only the modal numbers and the loss or structural alteration of a #22.

Hypodiploid, pseudodiploid, and normal karyotypes prevail in cytogenetic studies of medullary carcinomas of the thyroid and metastatic tissues.

Medullary carcinoma of the thyroid (MCT), often a dominantly inherited neoplasm, derived from intrathyroid C-cells of neural crest origin, is one of the solid tumors least studied cytogenetically. The cells are difficult to grow in culture, only two cell lines having ever been established. Cytogenetic studies of only 5 tumors have been reported previously. In this paper we report on the cytogenetic analyses of 8 specimens of primary and/or metastatic MCT tumor tissue from 6 patients with familial disease, including more recent metastatic tumors in lymph node and femur of a patient whose thyroid and earlier lymph node metastases were described previously. Some of these specimens were harvested sequentially over time. Hypodiploid or diploid modal numbers prevailed with normal, pseudodiploid, or hypodiploid karyotypes.

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.

Azaserine-induced rat pancreas tumor model with transplantable cultured cells.

The purpose of this study was to describe the inoculation technique and patterns of growth as well as to characterize typical histological features of Lewis rat subcutaneous and intrapancreatic tumors, induced by inoculation of cultured pancreatic cancer cells (DSL-6A/C1). Subcutaneous inoculation of cultured cells produced a solid tumor that was a locally invasive, well- to moderately differentiated ductal adenocarcinoma. Tumor take was 100% in animals 5 weeks of age; tumor growth was consistent and predictable and a tumor volume of approximately 1 cm3 was reached in 8 weeks. After intrapancreatic transplantation the tumors showed the same histological features as subcutaneous tumors. During inoculation carcinoma cells easily spread around the injected area, and after 2 weeks both pancreatic tumors and superficially infiltrating carcinomas were found in the liver and spleen and around the peritoneum. Tumor take was 60% and tumor growth was somewhat indefinite and unpredictable in the pancreas. However, by reducing the injected carcinoma cell volume and solving the technical problems, 100% tumor take was achieved. The tumor volume reached 2 mm3 during 2 weeks and larger tumors showed a tendency for invasion. According to our results, subcutaneous as well as intrapancreatic tumor induction with cultured cells offers a model for pancreatic cancer studies.