Subunits of human chorionic gonadotropin: unbalanced synthesis and secretion by clonal cell strains derived from a bronchogenic carcinoma

Expression of human chorionic gonadotropin-β in tissue specimens, saliva and urine of oral squamous cell carcinoma patients

Background:

Oral squamous cell carcinoma (OSCC) remains as one of the leading causes of death in many of the developing countries including India. Early detection helps in improving the prognosis and survival rates. Over the years, tumor markers continue to play an important role in diagnosing and monitoring cancer progression. The ectopic production human chorionic gonadotropin-β (hCG-β) is one such marker that is seen in various nontrophoblastic cancers and serves as a marker for tumor prognosis. Few immunohistochemical studies have shown the presence of hCG-β in oral cancers too. The present study investigated the immunohistochemical expression, levels of hCG-β in saliva and urine of various grades of OSCC patients and correlated it with their histopathological grading.

Materials and Methods:

Tissue sections of 50 histologically confirmed OSCC were subjected to immunohistochemical staining by using hCG-β antibody (well differentiated – 21, moderately differentiated – 21 and poorly differentiated – 8). The levels of hCG-β in saliva and urine were estimated in these individuals, by using Beckman Coulter Access 2 automated immunoassay system and comparisons drawn.

Results:

hCG-β immunopositivity was seen in 8 (38%) of 21 well-differentiated, 11 (52%) of 21 moderately differentiated and 6 (75%) of 8 poorly differentiated OSCC specimens. The levels of hCG-β in both saliva and urine were increased in poorly differentiated (0.40 and 1.19 mIU/ml) than moderately (0.3 and 0.76 mIU/ml) and well-differentiated (0.36 and 0.48 mIU/ml) OSCC patients.

Conclusion:

Immunohistochemical expression, salivary and urine levels of hCG-β could serve as an independent prognostic indicator in OSCC patients.

Immunohistochemical study of the expression of human chorionic gonadotropin-β in salivary gland tumors

Background and Objectives

Human chorionic gonadotropin-β (hCGβ) is a hormone glycoprotein usually secreted by trophoblastic cells in early pregnancy and helps in growth and development of the embryo. While many trophoblastic and nontrophoblastic malignancies express elevated levels of hCGβ in serum, increased immunohistochemical reactivity has also been reported in malignant and aggressive tumors, thus serving as a marker. As limited studies exist on tumors of the oral- and para-oral region, it prompted us to observe the immunohistochemical expression of hCGβ in salivary gland tumors.

Materials and Methods

A total of 21 cases of salivary gland tumors - 16 cases of mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (ACC), and five cases of pleomorphic adenoma - were included in the study. The sections were subjected to immunohistochemical procedures using hCGβ antigen. The degree of intensity and distribution of hCGβ immunostaining was assessed.

Results

One case of each (12.5%) MEC and ACC showed positive staining, and no staining was observed in the pleomorphic adenoma.

Conclusion

The presence of hCGβ positive tumor cells appears to potentially reflect the aggressive behavior of MEC and ACC.

Identification of a novel glucocorticoid receptor mutation in budesonide-resistant human bronchial epithelial cells

We developed a molecular genetic model to investigate glucocorticoid receptor (GR) signaling in human bronchial epithelial cells in response to the therapeutic steroid budesonide. Based on a genetic selection scheme using the human Chago K1 cell line and integrated copies of a glucocorticoid-responsive herpes simplex virus thymidine kinase gene and a green fluorescent protein gene, we isolated five Chago K1 variants that grew in media containing budesonide and ganciclovir. Three spontaneous budesonide-resistant subclones were found to express low levels of GR, whereas two mutants isolated from ethylmethane sulfonate-treated cultures contained normal levels of GR protein. Analysis of the GR coding sequence in the budesonide-resistant subclone Ch-BdE5 identified a novel Val to Met mutation at amino acid position 575 (GRV575M) which caused an 80% decrease in transcriptional regulatory functions with only a minimal effect on ligand binding activity. Homology modeling of the GR structure in this region of the hormone binding domain and molecular dynamic simulations suggested that the GRV575M mutation would have a decreased affinity for the LXXLL motif of p160 coactivators. To test this prediction, we performed transactivation and glutathione-S-transferase pull-down assays using the p160 coactivator glucocorticoid interacting protein 1 (GRIP1)/transcriptional intermediary factor 2 and found that GRV575M transcriptional activity was not enhanced by GRIP1 in transfected cells nor was it able to bind GRIP1 in vitro. Identification of the novel GRV575M variant in human bronchial epithelial cells using a molecular genetic selection scheme suggests that functional assays performed in relevant cell types could identify subtle defects in GR signaling that contribute to reduced steroid sensitivities in vivo.

Beta human chorionic gonadotropin concentrations in serum of patients with pancreatic adenocarcinoma

BACKGROUND

Human chorionic gonadotropin (hCG) is normally produced and secreted by trophoblastic cells during pregnancy and from gestational trophoblastic neoplasms. It is also detected in ovarian, stomach, and colon adenocarcinomas, as well as in squamous cell carcinoma of the oesophagus. Recently, interest in its role in the pathogenesis of tumours has been enlivened after the presence of beta hCG in the cell membrane of several malignant cells was shown in vitro.

AIMS

To investigate the circulating concentrations of beta hCG in patients with exocrine pancreatic adenocarcinoma and to examine its potential prognostic value.

PATIENTS

Thirty six patients with exocrine pancreatic adenocarcinoma, 12 patients with chronic pancreatitis, and 21 healthy volunteers were studied.

METHODS

beta hCG serum concentrations were detected by the application of a radioimmunoassay technique.

RESULTS

Fifteen of 36 patients with pancreatic adenocarcinoma and only one patient with chronic pancreatitis had detectable plasma concentrations of beta hCG (p < 0.01). The patients with circulating serum titres of beta hCG had a worse outcome compared with the group of beta hCG negative patients: the difference was statistically significant (p = 0.01).

CONCLUSION

More than 40% of pancreatic exocrine tumours produce beta hCG and its production is correlated with an adverse effect on outcome.

Expression of the alpha subunit of human chorionic gonadotropin in normal and neoplastic neuroendocrine cells. An immunohistochemical study

The alpha subunit of human chorionic gonadotropin (HCG) was localized Immunohistochemically in paraffin sections of normal human tissues and neuroendocrine tumors. A small subset of dispersed neuroendocrine cells was positive in normal adult tissues, including gastric antrum, urachal remnant, anal glands and prostate. Positive cells were consistently present in perinatal lung but rare in adult lung. In contrast, the beta subunit was absent from these cells. Seventy-two of 151 extrapituitary neuroendocrine tumors (48%) were alpha subunit-positive. Thirty-three of 37 bronchial carcinoids (92%) were immunoreactive, with a high percentage of the tumors (54%) containing moderate to large numbers of positive cells. The alpha subunit was further demonstrated in 9 of 45 small cell lung carcinomas (20%), 19 of 35 extrapulmonary carcinoids (54%), 3 of 11 islet cell tumors (27%) and 8 of 13 medullary thyroid carcinomas (62%). Two of three malignant islet cell tumors were positive. Positive cells were usually few in number, except for two small cell lung carcinomas, two rectal carcinoids, one thymic carcinoid and one malignant islet cell tumor. Pheochromocytomas (n = 10) were negative. Eleven of 19 pulmonary tumorlets (58%) were alpha subunit-immunoreactive. A few beta subunit-positive cells were detected in only 6 lung lesions. The physiological significance of the imbalance of expression of HCG subunits by certain neuroendocrine cells and their tumors remains unknown.

Loss of tumorigenic potential by human lung tumor cells in the presence of antisense RNA specific to the ectopically synthesized alpha subunit of human chorionic gonadotropin

A clonal strain of human lung tumor cells in culture (ChaGo), derived from a bronchogenic carcinoma, synthesizes and secretes large amounts of alpha (alpha) and a comparatively lower level of beta (beta) subunit of the glycoprotein hormone, human chorionic gonadotropin (HCG). ChaGo cells lost their characteristic anchorage-independent growth phenotype in the presence of anti-alpha-HCG antibody. The effect of the antibody was partially reversed by addition of alpha-HCG to the culture medium. ChaGo cells were transfected with an expression vector (pRSV-anti-alpha-HCG), that directs synthesis of RNA complementary to alpha-HCG mRNA. The transfectants produced alpha-HCG antisense RNA which was associated with the reduced level of alpha-HCG. Transfectants also displayed several altered phenotypic properties, including altered morphology, less mitosis, reduced growth rate, loss of anchorage-independent growth, and loss of tumorigenicity in nude mice. Treatment of transfectants with 8,bromo-cAMP resulted in increased accumulation of alpha-HCG mRNA, no change in the level of alpha-HCG antisense RNA, release of the inhibition of [3H]thymidine incorporation, and restoration of anchorage-independent growth phenotype. The overexpression of c-myc, observed in ChaGo cells, was unaffected by the reduced level of alpha-HCG. These results suggest that ectopic synthesis of the alpha subunit of HCG plays a functional role in the transformation of these human lung cells.

Human chorionic gonadotropin in the rectosigmoid colon. Immunohistochemical study on unbalanced distribution of subunits

For investigation of cellular localization of subunits of human chorionic gonadotropin (hCG) in normal and neoplastic rectosigmoid colon, immunohistochemical studies were performed on nonneoplastic colons (10 fetuses, 3 infants, and 23 adults, including 4 cases of ulcerative colitis) and 7 carcinoid tumors, 19 adenomas, and 50 carcinomas of the rectosigmoid colon. The alpha-hCG immunoreactive cells were present in endocrinelike cells of non-neoplastic glands (6 fetuses older than 14th gestational week, 3 infants and 19 of 23 adults). Many of the positive cells were argyrophilic, and all were nonimmunoreactive for beta subunits of glycoprotein hormones. alpha-hCG immunoreactivity was also present in many argyrophilic cells of all carcinoid tumors and in some of the endocrine cell micronests. The immunoreactive cells for isolated beta-hCG were found in 14 infiltrating carcinomas. The distribution of hCG subunits was unbalanced, and both subunits may be expressed through an independent mechanism, commonly in normal and neoplastic rectosigmoid colon.

Human chorionic gonadotropin in gastric carcinoma. An immunohistochemical study suggesting independent regulation of subunits

To investigate the production of human chorionic gonadotropin (hCG) in gastric carcinoma, 124 gastric carcinomas and a choriocarcinoma with adenocarcinoma were examined immunohistochemically, using anti-hCG alpha and beta antibodies. In choriocarcinoma, many trophoblastic cells were synchronously positive for both subunits. In contrast, the distribution of hCG-subunits in gastric carcinoma was unbalanced with hCG alpha in 39 and hCG beta in 63 cases. 26 cases contained alpha and beta positive cells, whereas synchronous cells were extremely rare in four cases. Incidences of hCG-subunit-positivities were not different between early and advanced carcinomas. HCG alpha-positive cells appeared endocrine-like in papillotubular carcinomas and some positive cells were argyrophilic in serial sections in 23 of 39 cases. HCG beta-positive cells were much more frequent in deranged glands, especially of microtubular-mucocellular carcinomas and most were not argyrophilic. In surrounding non-neoplastic mucosa, hCG alpha-positive cells were more numerous with endocrine-like configurations, but hCG beta-positive cells were rarely present in deranged glands. Although subunit-profile of hCG in gastric carcinomas was different from that of normal, the difference may be quantitative: hCG-subunits may be expressed through an independent mechanism but commonly in gastric mucosa and carcinoma. These results are also discussed in relation to trophoblastic tumours arising in non-trophoblastic tissues.

Mechanism of benzo(a)pyrene induction of alpha-human chorionic gonadotropin gene expression in human lung tumor cells

Human lung cells (ChaGo) derived from a bronchogenic carcinoma synthesize and secrete in the culture medium the alpha subunit of the glycoprotein hormone, human chorionic gonadotropin (alpha-hCG). The synthesis of alpha-hCG by ChaGo cells could be further stimulated by treatment with sublethal concentrations of the polycyclic aromatic hydrocarbons (PAHs), benzo(a)pyrene (BaP), or dimethylbenzanthracene. The production of alpha-hCG could be correlated to the levels of alpha-hCG-specific mRNA sequences in control and PAH-treated cells. Further analysis of the RNA species (Northern blot) revealed that the level of the mature (approximately 1.0 kb) and the high molecular weight alpha-hCG specific nuclear RNA sequences (approximately 2.2 and 5 kb) were all greater in PAH-treated cells. Addition of [3H]BaP (0.25 microgram/ml) in the culture medium of ChaGo cells led to immediate uptake of the radioactive compound apparently by simple diffusion. SDS PAGE and subsequent fluorography revealed that the radioactive compound interacted and formed covalent complexes with cytoplasmic and nuclear proteins. This covalent interaction of the [3H]BaP molecule with cellular proteins could be significantly inhibited by either inhibiting the activity of the enzyme aryl hydrocarbon hydroxylase with 7,8-benzoflavone or by reducing the cellular concentration of the enzyme by simultaneous incubation with cycloheximide. These results suggested that in ChaGo cells, the observed covalent complexes were formed by the interaction of the BaP metabolites with cellular proteins. The concentrations at which 7,8-benzoflavone or cycloheximide inhibited formation of metabolites from [3H]BaP and their covalent interaction with cell protein did not affect the BaP-induced stimulation of alpha-hCG gene expression. However, the cytotoxic effects of BaP in ChaGo cells seemed to be exerted by the metabolism of the compounds. Results presented in this report suggest that BaP metabolism and the interaction of the metabolites with cell proteins were not essential for the BaP-induced modulation of alpha-hCG gene expression.

Human chorionic gonadotropin and human placental lactogen in extragonadal tumors. An immunoperoxidase study of ten non-germ cell neoplasms

The immunoperoxidase localization of the alpha and beta subunits of human chorionic gonadotropin (hCG) and of human placental lactogen (hPL) was studied in ten extragonadal nontrophoblastic tumors associated with raised serum levels of one or more of these placental proteins. Three of the tumors were bronchial carcinomas, one was a gastric carcinoma, two were malignant carcinoids (one bronchial and one gastric), two were pancreatic islet cell carcinomas, and two were metastatic carcinomas with an unknown primary site. The maximum alpha subunit serum level was 33,000 ng/ml (gastric carcinoid), the maximum hCG/hCG-beta level was 705,000 ng/ml, and the maximum hPL level was 50 ng/ml (both in the gastric carcinoma). An indirect immunoperoxidase technique and rabbit polyclonal affinity-purified antibodies and peroxidase conjugates were used on formalin-fixed, paraffin-embedded sections. Five blocks (eight cases) or six blocks (two cases) from various sites were obtained from each patient at surgery and/or autopsy. Positive stains for hCG/hCG-beta were seen in six of seven tumors (25/37 blocks) with raised levels, for the alpha subunit in nine of nine tumors (30/47 blocks), and for hPL in two of five tumors (4/26 blocks). Only a relatively minor number of the cells were positive, and within the same case, there was considerable site-to-site variation in the number of positive cells. Large bizarre cells contained hCG/hCG-beta as well as the alpha subunit, if it was demonstrated in the same tumor as the beta subunit. Otherwise, the alpha subunit was found in small unremarkable cells. Giant cells that were smaller than those positive for hCG/hCG-beta contained in hPL. In some serial sections, hCG-alpha, hCG/hCG-beta, and hPL were segregated in different cell populations, supporting the concepts of their separate genetic control.

Glycoprotein-hormone alpha-chain production by pancreatic endocrine tumors: a specific marker for malignancy. Immunocytochemical analysis of tumors of 155 patients

Human chorionic gonadotropin (hCG) or its alpha- and beta-subunits have been proposed as specific quantitative markers for malignant pancreatic endocrine tumors. Since proof of malignancy of pancreatic endocrine tumors is difficult early in the course of the illness, we tested retrospectively a series of 157 pancreatic endocrine tumors of 155 patients for alpha- or beta-subunits of hCG by immunocytochemistry. Human CG-alpha-immunoreactive cells were present in 42 of 56 (75%) functioning malignant pancreatic endocrine tumors but in only one, possibly benign, glucagonoma of 67 functioning benign tumors, in only one of 17 nonfunctioning malignant and in none of 17 nonfunctioning benign tumors. No beta-hCG-immunoreactivity was localized in the tumors. Human CG-alpha appears to be a reliable quantitative and qualitative marker for malignancy in functioning pancreatic endocrine tumors.

Glycopeptide hormone production by cultured human diploid fibroblasts

Human diploid fibroblasts in culture were examined for production of glycopeptide hormones. Forty-one percent of the strains produced human chorionic gonadotropin (hCG) under normal growth conditions. Constitutive hCG synthesis was apparently unrelated to donor age, length of time in culture, or number of passages. Follicle stimulating hormone (FSH) was not found in any strain investigated. Only one cell strain produced free alpha-chains of glycopeptide hormones. Hydroxyurea (HU) at a concentration of 1 mM mediated a small, statistically significant increase in hCG production (p less than 0.01) in all constitutive strains, but had no effect on non-hCG-producing fibroblast strains. Sodium butyrate (Bu) was effective in increasing hCG synthesis in only one constitutive strain, derived from a newborn foreskin. HU treatment had no apparent effect on cell structure. All Bu-treated strains, both those producing hCG and the nonproducers, showed morphological alterations; cells were flattened and they contained ordered arrays of refractile granules. It is suggested that hCG synthesis in cultured human diploid fibroblasts may result from a localized chromosomal event in which the loci responsible for this hormone are activated. Human diploid fibroblasts in culture are shown to be amenable to the study of gene expression and its modulation.

Expression of the alpha subunit of human chorionic gonadotropin is specifically correlated with tumorigenic expression in human cell hybrids

The expression of HeLa parent phenotype protein markers, the alpha subunit of human chorionic gonadotropin and placental alkaline phosphatase isoenzymes, has been evaluated in paired tumorigenic and nontumorigenic HeLa-fibroblast human cell hybrids. Both of these proteins have been used clinically as markers of malignancy. The results showed that both are expressed in the hybrids. Expression of the gonadotropin subunit in the hybrids is specifically correlated with tumorigenicity; the placental alkaline phosphatase isoenzyme showed no such correlation and was expressed in both tumorigenic and nontumorigenic hybrids.

Cellular localization of AFP, hCG and its free subunits, and SP1 in embryonal carcinoma of the testis and ovary

An immunohistological study of AFP, hCG and its free subunits, and SP1 was investigated in 10 cases of non-seminomatous germ cell tumors of the testis and ovary. AFP was demonstrated in mononuclear embryonal tumor cells within embryonal carcinoma in a narrow sense, frequently in association with yolk sac tumor. AFP was more consistently demonstrated in vacuolated or elongated cells of yolk sac tumor, in which continuous transformation from tubular patterns of embryonal carcinoma was shown with positive reactions for AFP. The hCG was demonstrated in syncytiotrophoblastic giant cells scattered among the embryonal carcinoma, but rarely in mononuclear large cells. The occurrence of hCG and beta subunit was more frequently observed than a subunit or SP1, suggesting the unbalanced synthesis of hCG and free subunit in choriocarcinomatous element associated with embryonal carcinoma. These findings support the view that embryonal carcinoma has a developmental potential to the extra-embryonic components of both choriocarcinoma and yolk sac tumor.

Pure alpha-secreting pituitary adenomas

Isolated hypersecretion of the alpha subunit of the glycoprotein hormones occurred in two men with previously diagnosed "nonfunctioning chromophobe adenomas." The alpha hypersecretion was unresponsive to hypothalamic releasing hormone, thyroid hormone, and sex-steroid hormones. After trans-sphenoidal surgery and conventional pituitary irradiation, alpha secretion was decreased. Increased quantities of immunologically active and biologically inactive luteinizing hormone (LH) material were detected in serum and in tumor homogenate. Immunologic and gel-chromatographic studies determined that only the alpha subunit was present and that it was cross-reacting in the LH immunoassay. These studies suggest that the alpha subunit may be a useful marker of pituitary tumors, particularly in patients without clinical evidence of hormonal hypersecretion.

Ectopic production in serum-free media of the common alpha subunit of the glycoprotein hormones

The HeLa-S3 cell strain grown in Ham's F12 medium supplemented with insulin, transferrin, cortisol, epidermal growth factor, fibroblast growth factor, and trace elements, but containing no serum, continued to produce the common alpha-subunit of the glycoprotein hormones for the 10 d study. The amounts of alpha-subunit secreted into the medium during the first 4 d were indistinguishable from those in F12 medium supplemented with 10% fetal bovine serum. During the remainder of the experiment the amounts of alpha-subunit reached 50 to 80% those in the serum-supplemented medium.

Predominance of gonadotropin alpha-subunit resulting from preferential loss of hCG beta production in an established cell line

The BeWo line of trophoblastic cells, maintained in continuous culture since 1966, was employed to investigate the phenomenon of gonadotropin alpha-subunit predominance that exists in several cell lines. The secretion of complete human chorionic gonadotropin (hCG) relative to alpha-subunit was compared in several different BeWo sublines, all of where were derived from BeWo stock roller tube colonies. In all of the BeWo sublines, secretion of hCG originally exceeded secretion of alpha-subunit. With time in culture, however, there was a marked decline in production of hCG/hCG beta, but not in alpha-subunit. Thus it appears that the production of hCG beta by BeWo choriocarcinoma cells is more labile than the production of the alpha-subunit.

Paraneoplastic syndromes

Neoplasms can produce a variety of remote effects on the host; these are referred to as paraneoplastic syndromes. The syndromes may affect any of the systems of the body, may precede or follow the diagnosis of the underlying neoplasm, and may or may not parallel the course of the neoplasm in severity. The diagnosis of and therapy for these syndromes can be challenging to a physician, but successful therapy may bring about worthwhile relief for the patient. In addition, the syndromes and the substances that cause them are sometimes useful in diagnosing and in following the course of certain neoplasms. Perhaps of greater importance, study of these remote effects of neoplasia may shed light on the nature of the neoplastic process itself.

An epithelial cell line (KNS-62) derived from a brain metastasis of bronchial squamous cell carcinoma

A brain metastasis of bronchial squamous cell carcinoma in a patient was cultivated. The cells with epithelium-like characteristics were selected from the primary culture, and were subcultured to establish a cell line. The cultured cells were identified to be neoplastic by means of heterologous transplantation to nude mice, in which tumors developed and reproduced histologic characteristics as were seen in the primary tumor of the patient.

Serum glycoprotein hormone alpha subunit levels in patients with cancer

The serum glycoprotein hormone alpha subunit concentration was measured in 957 nonpregnant patients with benign disorders and 683 patients with unselected malignancies. Postmenopausal women had significantly higher alpha levels than premenopausal women or men. When the patients were subdivided according to age, sex or disease sites, significant population differences were found for women less than 50 years of age and patients with cancers of presumed neural crest origin. However, individual serum alpha levels in patients with benign disorders or malignancies demonstrated considerable overlap. No population differences in serum alpha concentrations were demonstrated between patients grouped according to stage of disease, suggesting that serum alpha were not directly related to tumor burden. Similarly, there was no statistical association between clinical improvement or deterioration and change in the serum alpha subunit concentration. These results indicate that measurement of the glycoprotein hormone alpha subunit concentration in the serum is not useful for screening patients for cancer or for monitoring the clinical course of patients with the vast majority of cancers.

Synthesis and processing of human chorionic gonadotropin subunits in cultured choriocarcinoma cells

Pulse and pulse-chase experiments have identified the presence of partially glycosylated precursors of the alpha and beta subunits of human chorionic gonadotropin (hCG) in cultured JAR choriocarcinoma cells. The alpha subunit precursor has an apparent molecular weight (by sodium dodecyl sulfate/polyacrylamide gel electrophoresis) of 18,000 (compared to 22,000 for fully processed alpha subunit); the beta subunit precursor has an apparent molecular weight of 24,000 (fully processed, 34,000). Both of these precursors appear to have an intracellular half-life of at least 1 hr and to contain the mannose core but not the terminal carbohydrate sequences. Fully processed alpha and beta subunits do not accumulate intracellularly, indicating that further processing of the precursors is followed by rapid secretion.

Necessity for two human chromosomes for human chorionic gonadotropin production in human-mouse hybrids

Through a series of human-mouse hybrids we have identified that two human chromosomes, 10 and 18, must be present for production of the pregnancy protein hormone human chorionic gonadotropin (hCG). Human choriocarcinoma cells producing hCG were hybridized to mouse cells. From 49 independent clones three hybrid clones continued to produce whole hCG. Chromosomal analysis was done on the 3 producer clones and 5 nonproducer clones. The additional 41 nonproducer clones were genetically characterized by isozymes. Only when chromosomes 10 and 18 were present in a clone would the whole hCG molecule be produced. Clones with only 10 or only 18 did not produce hormone. Nine subclones of a producer clone confirmed this observation. Three subclones retaining both 10 and 18 continued to produce hCG. This study demonstrated the need to use cellular chromosome data and population enzyme data to identify two chromosomes necessary for hCG production in heterogeneous human-mouse hybrids.

Identification of separate mRNAs coding for the alpha and beta subunits of thyrotropin

A 9S mRNA, purified from mouse thyrotropic pituitary tumors by sucrose density gradient centrifugation of poly(A)-enriched mRNA, directed the synthesis of only alpha and beta subunits of thyrotropin in the reticulocyte lysate translation system. Analysis of radioiodinated 9S mRNA, repurified by oligo(dT)-cellulose chromatography and sucrose gradient centrifugation, yielded two species of RNA on urea/polyacrylamide gel electrophoresis. The major RNA species contained 620 nucleotides, and the minor RNA species contained 560 nucleotides. Unlabeled 9S mRNA was further purified by urea/polyacrylamide gel electrophoresis; the mRNAs were separately eluted from slices of the gel containing material migrating with an apparent length of 620 and 560 nucleotides. Translation of these mRNAs in the reticulocyte lysate showed that the longer mRNA coded for the alpha subunit and the shorter mRNA coded for the beta subunit of mouse thyrotropin. Because more alpha than beta subunit of thyrotropin was consistently synthesized, unbalanced amounts of thyrotropin subunits appear to be synthesized by translation of unbalanced amounts of individual mRNAs. We have demonstrated that the synthesis of thyrotropin is directed by two separate mRNA molecules, each coding for a different subunit of the hormone.

Induction of human choriogonadotropin and follitropin in HeLa cell cultures by hyperosmolality

The growth of cervical carcinoma cell (HeLa) cultures in a hyperosmolar environment stimulates increased production of the onco-developmental peptides human choriogonadotropin (hCG) and follitropin (FSH). This effect was observed in two sublines examined in this study, HeLa65 and HeLa71. hCG and FSH were measured by radioimmunoassay using antiserum against the beta-subunit of the hormone dimer, thus insuring immunochemical specificity, The amounts of hCG and FSH produced by HeLa65 and HeLa71 cells cultured in hyperosmolar medium were 2- to 50-fold higher than corresponding hormone levels in basal cultures. Synthesis of gonadotropins depended on concentration and duration of exposure to hyperosmolar medium. Levels of culture medium osmolality effective in inducing hormone production also inhibit the incorporation of 14C-thymidine into acid-insoluble macromolecules. Hyperosmolality thus stimulates the ectopic production of gonadotropic hormones while retarding cellular growth and nucleic acid synthesis.

mRNA-directed biosynthesis of alpha subunit of thyrotropin: translation in cell-free and whole-cell systems

mRNA from mouse thyrotropic pituitary tumors was translated in frog oocytes (a whole-cell system) and in wheat germ extract and reticulocyte lysate (cell-free systems) in the presence of [(35)S]methionine. Synthesized peptides related to thyrotropin were identified in the three systems by immunoprecipitation with subunit-specific antisera developed against the alpha subunit of ovine lutropin (luteinizing hormone) and the beta subunit of bovine thyrotropin. In wheat germ extract and reticulocyte lysate, a single immunoprecipitable form of the alpha subunit of thyrotropin was synthesized with an apparent molecular weight of 14,000 by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. In the frog oocyte, three forms of immunoprecipitable alpha subunit of thyrotropin were synthesized with apparent molecular weights of 20,000, 14,000, and 10,000. The 20,000 form is similar to unlabeled rat pituitary standard alpha subunit and (35)S-labeled mouse tumor alpha subunit in cell cultures (20,000-21,000); thus, it may represent a precursor-cleaved and glycosylated form. The 14,000 form synthesized in all three systems probably represents the pre-alpha subunit of thyrotropin; the 10,000 form, synthesized only in the frog oocyte, could be a proteolytically cleaved but unglycosylated form. Because only the alpha subunit of thyrotropin was identified and no larger molecular weight immunoprecipitable form of either subunit was detected in any of the translation systems, alpha and beta subunits of thyrotropin appear to be translated from separate mRNAs.

Regulation of alkaline phosphatase expression in human choriocarcinoma cell lines

The coincident expression of two structurally distinct isoenzymes of human alkaline phosphatase was demonstrated in two independently derived gestational choriocarcinoma cell lines. These proteins were shown to have enzymatic, antigenic, and physical-chemical properties resembling those of isoenzymes from term placenta and adult liver. The regulation of these isoenzymes has been studied during the exposure of both cell lines to 5-bromodeoxyuridine and dibutyryl cyclic AMP. The responses of the alkaline phosphatase isoenzymes to these agents have also been compared with the response of another protein phenotypic to placenta, the alpha subunit of chorionic gonadotropin. The results show that (i) the separate structural genes coding for placental and liver alkaline phosphatases are regulated in a noncoordinate fashion; (ii) both alkaline phosphatase genes respond independently of the alpha subunit; and (iii) the induction of the placental type isoenzyme occurs via at least two independent pathways.

Variable content of histaminase, L-dopa decarboxylase and calcitonin in small-cell carcinoma of the lung. Biologic and clinical implications

To ascertain whether the content of endocrine markers is constant in small-cell carcinoma of the lung, levels of three markers of medullary thyroid carcinoma were studied in this tumor. Histaminase was increased in six of six primary tumors (three to 14,000 times), L-dopa decarboxylase in four of six (six to 30 times), and calcitonin in one of one (eight times) over levels in adjacent lung. Marker levels in mediastinal metastases reflected those in primary tumors in four of five patients. However, in four of seven, multiple hepatic metastases contained low to absent levels despite simultaneously high values in chest lesions. Immunohistochemical studies of histaminase revealed that within each primary tumor different cells contained different amounts of the enzyme. Since marker content varied between tumor cells, between primary tumors and between metastases in individual patients we conclude that circulating levels of these three markers cannot be expected necessarily to mirror tumor burden in patients with small-cell lung tumors.

Establishment of clonal human placental cells synthesizing human choriogonadotropin

Seven clonal human placental cell lines were established by transformation of human first-trimester placental cells with simian virus 40. These transformed cells synthesized native human choriogonadotropin (chorionic gonadotropin) (hCG) as well as the free alpha and beta subunits of hCG. The amount of native hCG synthesized by these cells was, however, lower than the amount of free beta subunit. (Both hCG and the beta subunit are detected by the radioimmunoassay for beta subunit, but only hCG is detected by the radioreceptor assay.) The alpha and beta subunits produced by these transformed placental cells were heterogeneous in size; the sizes of the predominant alpha and beta species, however, corresponded to those of urinary alpha and beta subunits, respectively. The seven cell lines transformed by simian virus 40 had chromosome numbers from the near diploid to the near tetraploid range. Fluorescent staining demonstrated the Y chromosome in all the transformants. Furthermore, B-type glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase; EC 1.1.1.49) was present in all seven lines. These characteristics ruled out possible HeLa contamination of the transformed lines. Regulation of the synthesis of alpha and beta subunits plus hCG in these transformed human placental cells differed from the regulation in choriocarcinoma cells.

Immunohistochemical localization of a choriogonadotropin-like protein in bacteria isolated from cancer patients

By the use of specific antibody to human chorionic gonadotropin (CG) as well as to its beta-subunit, and the application of the indirect fluorescein-labeled and peroxidase-labeled antibody techniques, we have demonstrated the presence of a membrane (wall)-associated CG-similar immunoreactive protein in 15 strains of bacteria isolated from tissues of patients bearing malignant neoplasms. These microorganisms were classified as S. epidermidis, (12) E. coli (2), and a single strain of P. maltophilia (ATCC 13637). The absence of the CG-like antigen in other "cancer associated bacteria", Streptococcus faecalis (ATCC 12818) and Pseudomonas aeruginosa (from patient with cancer of colon), demonstrated that not every "cancer associated bacteria" has the capability to synthesize the trophoblastic-like protein. The negative results obtained with a number of "noncancer control" bacteria of known origin, obtained from ATCC and from clinical samples, strongly supported the idea that the existance of these CG-like protein producing microorganisms is not a ubiquitous finding. The demonstration of a de novo bacterial biosynthesis of a protein having similar antigenic and biophysical properties to those of the human trophoblastic hormone, has great biological implications, especially if its biosynthesis is proven only in bacterial strains growing in the presence of cancer cells in which we have already demonstrated the presence of a similar antigen. The explanation of the phenomenon is unknown. Because of their origin, the potential of "genetic exchange" with subsequent expression of the mammalian gene by the bacterial cells becomes a possibility. It is also possible that the gene coding for the CG-like protein is normally present but inactive or repressed in all bacteria.

Significance of alpha-subunit HCG demonstrated in breast carcinomas by the immunoperoxidase technique

Fifty-three breast carcinomas were examined by an indirect immunoperoxidase technique for the presence of the alpha-subunit of human chorionic gonadotrophin. Positive staining occurred in 12 (22.6%). There was no correlation between alpha-subunit production and specific histological features, but production was related to the presence of lymph node metastases and hence a poorer prognosis. The alpha-subunit could be used as a prognostic indicator in the assessment of breast carcinoma.

Production of a low molecular weight eosinophil polymorphonuclear leukocyte chemotactic factor by anaplastic squamous cell carcinomas of human lung

A peptide of approximately 300-400 daltons exhibiting in vitro chemotactic activity for human polymorphonuclear (PMN) leukocytes, with a preference for the eosinophil series, was isolated from extracts of anaplastic lung carcinomas of the large squamous cell type obtained from three patients with marked peripheral blood hypereosinophilia and eosinophilic infiltration of the tumors and surrounding normal pulmonary tissues. This chemotactic factor was termed ECF-LSC (eosinophil chemotactic factor of lung squamous cell carcinoma). ECF-LSC appeared in the urine of two of the patients in increasing quantities late in the course of their disease and was also elaborated by long-term cultures of dispersed tumor cells from the same two patients. Three anaplastic large cell bronchogenic carcinomas which were not associated with tumor tissue or peripheral blood eosinophilia, a bronchogenic adenocarcinoma from a patient with only peripheral eosinophilia, and a renal cell carcinoma metastatic to the lungs and associated with transient pleural tissue and fluid eosinophilia were all devoid of ECF-LSC. ECF-LSC from tumor tissue extracts, urine, and tumor cell culture medium was comparable to the mast cell-associated tetrapeptides of the eosinophil chemotactic factor of anaphylaxis (ECF-A) in size, but eluted from Dowex-1 at pH 5.0-3.5 in contrast to the more acidic ECF-A tetrapeptides which eluted at pH 3.2-2.2 ECF-LSC, like the tetrapeptides of ECF-A, had a secondary chemotactic activity for neutrophil PMN leukocytes, but not mononuclear leukocytes, and deactivated both eosinophil and neutrophil PMN leukocytes so that they would not respond to a subsequent in vitro chemotactic stimulus. Eosinophils from the two patients with urinary excretion of ECF-LSC and the highest concentrations in tumor extracts were hyporesponsive in vitro to homologous and heterologous chemotactic stimuli, suggesting that ECF-LSC had deactivated the eosinophils in vivo.

Ectopic production of chorionic gonadotropin and its subunits by islet-cell tumors. A specific marker for malignancy

We measured human chorionic gonadotropin (hCG) and its subunits in 76 patients with islet-cell tumors. Seventeen of 27 patients with functioning islet-cell carcinomas had elevated plasma levels of hCG or one of its subunits (hCG-alpha and hCG-beta). Secretion was often discordant; the most frequent finding was an elevated level of hCG-alpha alone. In one patient responding to streptozocin, changes in hCG-alpha correlated with the clinical course. Studies of tumor extracts suggested that the markers observed in the circulation were being produced in the tumor itself. In contrast, none of the 43 patients with benign disease or the six patients with nonfunctioning malignant tumors had elevated levels of hCG, hCG-alpha or hCG-beta. These data show that hCG and its subunits are prevalent and specific markers for islet-cell carcinoma, and suggest that ectopic secretion results from malignant derepression of the genome rather than overproduction by an aberrant "cell rest."

Placental proteins and their subunits as tumor markers in prostatic carcinoma

Sixteen patients with Stage D adenocarcinoma of the prostate were prospectively evaluated for the presence of human placental lactogen (hPL), placental alkaline phosphatase (PAP), and human chorionic gonadotropin (hCG). Ectopic production of hCG was found in one of the 16 cases and is described in detail. Serial serum hCG levels in that patient mirrored his course more reliably than concomitant acid phosphatase levels. Serum estradiol, testosterone, the hCG-alpha subunit, hPL and PAP were not elevated. There was a minimal elevation of serum FSH. There were no elevations of the other placental proteins in ten evaluable cases. A retrospective evaluation of serum bank specimens from 47 patients with prostatic carcinoma revealed no elevation of the placental proteins hPL, hCG-beta, and hCG-alpha. To our knowledge this report documents the first case of a chorionic gonadotropin-producing prostatic carcinoma appearing the literature.

Synthesis of alpha subunit of human chorionic gonadotrophin by presumptive HeLa cells

Several cell lines, originally thought to be derived from a human placenta at term but possibly HeLa-contaminated, have been studied. These cells secrete a protein indistinguishable immunochemically from the alpha subunit of chorionic gonadotropin but not the beta subunit of chorionic gonadotropin or placental lactogen. Complete chorionic gonadotropin was detected but amounted to less than 1% of the level of the alpha subunit. The cells also produce an alkaline phosphatase similar to placental alkaline phosphatase in immunochemical, gel-electrophoretic, and heat-denaturation properties. They induce tumor growth when inoculated into nude mice. These cells are aneuploid and have a model chromosome number of 66. The common HeLa karyologic markers, designated 1, 2, and 3, and A-type glucose-6-phosphate dehydrogenase are present in these cells. HeLa cells have not previously been shown to secrete the alpha subunit of hCG.