Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To obtain insight into the secretion pattern of human chorionic gonadotropin (hCG) and its free subunits, hCG alpha and hCG beta, in vivo, we analyzed hydrocele fluids of 13 patients with testicular cancer and correlated the respective values to those of cubital vein and testicular vein serum. As a control population, patients with nonmalignant hydroceles (n = 11) were studied. Analyses were performed with a set of highly sensitive and specific time-resolved fluoroimmunoassays based on our own panel of monoclonal antibodies. In the collective of testicular cancer patients, increased hydrocele levels of either hCG or free hCG alpha or free hCG beta were observed in 77, 54, and 92% of cases; the corresponding percentages for cubital vein serum were 62, 23, and 31%. The cubital vein ratio of hCG:hCG alpha (546:1) and hCG:hCG beta (51:1) decreased to 64:1 and to 7:1 in the hydrocele fluids. Surprisingly, hydrocele fluids of five patients with pure seminoma, who were negative for the three markers in the periphery, revealed an elevation of free hCG beta in all cases, while hCG alpha and holo-hCG were elevated twice. Final proof that hCG beta and hCG alpha are indeed produced by these previously termed "marker negative" seminomas has been achieved by reverse transcriptase-polymerase chain reaction with primers specific for the alpha-subunit and the four most abundantly transcribed hCG beta genes 3, 5, 7, and 8. From these data, we conclude that: (alpha) seminomatous and nonseminomatous testicular cancers, irrespective of histology, secrete hCG and its free subunits; (b) the amount of free subunits being secreted in vivo by these tumors has been underestimated; and (c) the classification in marker-positive and marker-negative testicular cancer should be reconsidered.
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PMID:Human chorionic gonadotropin (hCG) and its free subunits in hydrocele fluids and neoplastic tissue of testicular cancer patients: insights into the in vivo hCG-secretion pattern. 792 24

Growth hormone (GH) and placental lactogen (PL) gene transcription patterns in testicular germ cell tumors (GCT) and normal testicular tissue were comparatively investigated to identify GH/PL gene products associated with the development of GCT. This was done by nondiscriminative reverse transcriptase-polymerase chain reaction (RT-PCR), amplifying all major transcripts of any of the 5 GH/PL genes--GH-N(ormal), GH-V(ariant), PL-A, PL-B, PL-L(ike)--and subsequent analytical restriction enzyme analyses of 5'-end radioactively labeled cDNA. Surprisingly, all nonseminomatous GCT (NSGCT; n = 9) expressed GH-N, PL-A/B, and PL-L transcripts (9 of 9). Seminoma (n = 7) showed a distinctly unique pattern of GH-N and PL-A/B. GH-V products, which are hallmarks of the normal healthy testis, were not detected in any testicular cancer specimen (0 of 16). The fact that both seminomatous and NSGCT showed alterations in the same gene cluster indicates a pathogenetic relationship. Two choriocarcinoma cell lines of conceptus origin, BeWo and JAR, clearly differing from the male counterparts, exhibited a placental-derived pattern of PL-A/B and GH-V. Obviously, profound differences exist between conceptus and male germ cell GH/PL gene cluster transcription. In summary, the unique testicular pattern of GH/PL gene expression changes significantly and in directed ways with malignancy. Loss of GH-V gene expression in testicular GCT compared with normal testis and loss (seminoma) or mutation (NSGCT) of PLL gene products might have significance in terms of the relationship between these tumors and for testicular GCT development.
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PMID:The testis-specific expression pattern of the growth hormone/placental lactogen (GH/PL) gene cluster changes with malignancy. 1053 68

Telomerase is a reverse transcriptase which helps to stabilize the length of telomeres by adding TTAGGG repeats onto the telomeres that enables unlimited division of the cell. Absence of telomerase activity causes replication senescence and cell death. Activity of telomerase was detected in embryonal, gonadal and cancer cells, but was not detected in adult somatic tissues with the exception of tissues containing stem cells. Telomerase inhibitors are being considered as potential anticancer drugs with the hope that the lack of telomerase expression in normal somatic cells would result in a higher specific therapy with fewer side effects than conventional chemotherapy. Because of high activity of telomerase in gonadal cells, we hypothesized that one of the drugs which selectively interfere with spermatogenesis may act like a telomerase inhibitor. Gossypol is a male contraceptive derived from cotton seeds. It causes suppression of spermatogenesis by an unknown mechanism. It has a non-endocrine inhibiting effect on spermatogenesis, gradual onset of action, and irreversible suppression of spermatogenesis with increasing length of use. It also has an antiproliferative effect on cell lines derived from tumors, mild antineoplastic action in vivo with few side effects. It has mild inhibiting influence on the replication of HIV via possible inhibition of reverse transcriptase HIV. This shows its possible telomerase inhibiting activity. It appears that gossypol is a potential new drug for testicular cancer therapy, because of its spermatotoxic and cytotoxic activity on cell lines derivided from testicular tumors. We posit that the use of gossypol in combination with other anticancer chemotherapeutics can lead to a more effective therapy of human tumors. (Ref. 47.).
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PMID:Telomerase inhibitors in anticancer therapy: gossypol as a potential telomerase inhibitor. 1258 8

Infertility has been stated as a risk factor for testicular cancer; but currently, there is no prognostic indicator of tumor development from the pathologic testis with impaired spermatogenesis. Regenerating proteins are expressed in many human tissues including the testis, and their role in carcinogenesis has been well documented. In the present work, regenerating I messenger RNA and protein expression and cellular protein localization were studied in testicular biopsies of patients with normal (obstructive azoospermia) or impaired spermatogenesis (nonobstructive azoospermia) and in seminoma testis by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunofluorescence analyses. No significant differences in regenerating I transcripts were reported between the 3 groups studied. However, regenerating I protein was highly expressed in pure seminoma and in placental-like alkaline phosphatase-positive seminiferous tubules with in situ carcinoma. Regenerating I protein levels measured by Western blotting increased from the placental-like alkaline phosphatase-negative distal region of the seminoma to the pure placental-like alkaline phosphatase-positive tumoral region. Importantly, although cells localized in seminiferous tubules of obstructive azoospermic patients with normal spermatogenesis were very slightly labeled, persisting germ, Sertoli, and myoid cells and fibrous tissues were strongly regenerating I positive in seminiferous tubules of nonobstructive azoospermia. These results suggest the possibility to use regenerating I as a prognostic marker of tumoral development in the infertile testis.
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PMID:Regenerating I messenger RNA and protein expression in the failing human testis: a potential molecular prognostic marker of seminoma. 2168 84