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)

Inhibition of the growth of hormone related human tumor cells in vitro by GnRH agonists and antagonists suggests a direct effect on cell growth and proliferation, and this effect may be achieved through its receptors present in tumor cells. However, the nature of the GnRH receptors present in these tumors is controversial. To determine the molecular characteristics of GnRH receptors in such tumors, we used the reverse transcriptase/polymerase chain reaction (RT/PCR) technique to clone these receptors. Primers were selected from the human pituitary GnRH receptor cDNA sequence to amplify the open reading frame and parts of its 5' and 3'-untranslated sequences. Nucleotide sequencing of the GnRH receptor cDNAs from a breast tumor cell line (MCF-7) and from an ovarian tumor showed identity with that of the human pituitary GnRH receptor which binds GnRH with high affinity. GnRH receptor mRNA was found to be expressed in human pituitary, breast, breast tumor, ovary, ovarian tumor, prostate, prostate tumor and in breast tumor cell lines (MCF-7 and MDA-MB 468) and prostate tumor cell lines (PC-3 and LNCaP). These findings demonstrate that a mRNA representing the pituitary form of the GnRH receptor (which shows high affinity binding with GnRH) is also expressed in certain normal tissues and in hormone related human tumors and tumor cell lines derived from them.
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PMID:The nucleotide sequences of human GnRH receptors in breast and ovarian tumors are identical with that found in pituitary. 753 32

Hepatocyte growth factor (scatter factor) and its receptor, the c-met proto-oncogene product (c-MET), have been implicated in embryogenesis, tissue reorganization, and tumor progression. Little is known, however, of the expression and functional significance of these molecules in prostatic cells and tissue. In this investigation, we assessed the expression of hepatocyte growth factor (HGF) and c-MET in prostatic tissues and cell lines and also determined the effect of purified recombinant HGF on cell proliferation and scattering of prostatic carcinoma cell lines. HGF was expressed by human prostatic stromal myofibroblasts in primary culture but not by three human prostatic carcinoma cell lines (LNCaP, DU 145, and PC-3) as assessed by Northern blot analysis. HGF was also detected by reverse transcriptase-polymerase chain reaction in both benign and malignant tissues from radical prostatectomy specimens. c-MET transcripts were identified by Northern blot in two androgen-insensitive human prostatic carcinoma cell lines (DU 145 and PC-3) but not the androgen-sensitive LNCaP cell line. Additional evidence of linkage of androgen responsiveness and c-MET was provided by experiments in which androgen deprivation of normal rat prostates via castration produced a marked up-regulation of c-MET expression as determined by Northern blot and immunohistochemistry. c-MET protein was detected by immunohistochemical analysis in a substantial percentage (58 of 128 or 45%) of prostatic carcinomas and was found more often in metastatic growths of human prostatic carcinoma (15 of 20 patients) compared with primary tumors (43 of 108 patients; P < 0.005). Moreover, in Dunning R-3327 rat prostatic carcinoma cell lines, c-MET expression was highest in the androgen-insensitive subline with the highest metastatic capacity. Purified recombinant human HGF induced dose-dependent cellular proliferation and scattering in the DU 145 carcinoma cell line. These data indicate that HGF may function in the prostate gland as a paracrine growth factor, with synthesis by stromal cells and with biological target cells being the epithelial cells. Expression of the HGF receptor, c-MET, is up-regulated by androgen deprivation and c-MET appears to be preferentially expressed on androgen-insensitive, metastatic cells, suggesting a possible linkage of c-MET expression with prostatic carcinoma progression.
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PMID:Hepatocyte growth factor and its receptor (c-MET) in prostatic carcinoma. 763 32

The expression of prostatic acid phosphatase (PAcP) in three human prostate carcinoma cell lines including LNCaP, DU 145 and PC-3, was studied to explore its potential role as a marker in the progression of prostate cancer. Although Southern blot analysis suggested the presence of PAcP gene in all three prostate carcinoma cell lines, the Northern blot analysis and the reverse transcriptase-polymerase chain reaction (RT-PCR) assay showed that PAcP mRNA can be detected only in LNCaP cells. As one of the major differences between LNCaP cells and PC-3 as well as DU 145 cells is the androgen-sensitivity of LNCaP cells, we then focused on the influence of PAcP expression by the presence of androgen receptor (AR) in human AR cDNA-transfected PC-3 cells and high passages of LNCaP cells. The results demonstrated that the transfection of human AR cDNA into PC-3 cells did not have any detectable effect on the expression of PAcP. Further, in LNCaP cells, while the level of PAcP mRNA diminished upon passage, the AR mRNA level remained approximately the same. Together, these data suggested that the differential expression of PAcP in different prostate carcinoma cells including high passages of LNCaP cells may occur at the transcriptional level and may have little linkage to the expression of AR.
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PMID:The expression of prostatic acid phosphatase is transcriptionally regulated in human prostate carcinoma cells. 764 50

Oestrogen receptors (ER) and progesterone receptors (PR) have been reported by several authors in the stromal cells of the human prostate. Controversial results exist on the expression of ER and PR in epithelial cells of the prostate. Some recent publications, in contrast to previous findings, have suggested that these receptors are also present in human prostate cancer cell lines derived from metastatic lesions. The expression of ER and PR in these cell lines has been re-examined to determine their presence in lymph node metastases from patients who did not receive any kind of endocrine therapy and in distant metastases obtained from patients who failed endocrine treatment. ER and PR expression in LNCaP, PC-3, and DU-145 cells was assessed by means of the reverse transcriptase-polymerase chain reaction, ligand binding assays, and immunohistochemistry. With all the techniques applied, the three cell lines were found to be negative for both ER and PR. Immunohistochemical analyses were performed in four lymph node metastases obtained at radical prostatectomy from patients who did not receive endocrine therapy and in 17 distant metastases obtained at palliative surgery from patients who failed endocrine therapy. All 21 metastases were negative for ER and PR on immunohistochemistry. These results do not support the recently developed concept that receptors for oestrogenic and progestagenic steroids are present in metastases from human prostate cancer.
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PMID:Metastatic lesions from prostate cancer do not express oestrogen and progesterone receptors. 982 44

Objectives: We investigated modulation of cell growth and prostate-specific antigen (PSA) gene expression in prostatic cancer cells by the luteinizing hormone-releasing hormone analog (LH-RHa), leuprorelin acetate, alone or combined with other agents. Methods: The effect of the analog on proliferation of both androgen-sensitive and -insensitive prostate cancer cells, maintained in different culture conditions, was evaluated by cell counts at various intervals of time. Basal expression of PSA gene and its variations were determined by a reverse transcriptase-polymerase chain reaction assay. Results: LH-RHa is ineffective in regulating cell growth, when used alone in both hormone-sensitive and -insensitive cell lines. Nevertheless, it counteracts the stimulatory action of androgens on proliferation of LNCaP cells, which respond to low concentrations of dihydrotestosterone. Moreover, LH-RHa has an inhibitory effect on the mitogenic action of epidermal growth factor (EGF) in androgen-unresponsive PC-3 cells. The analog reduces PSA gene expression in both hormone-sensitive and -insensitive cells. Interestingly, it counteracts the gene expression induced by androgens in LNCaP cells and by EGF in PC-3 cells. Conclusions: These data show that LH-RHa may behave like a negative growth factor, which directly regulates cell growth and PSA gene expression. Moreover, our findings support the idea that growth factors may interfere with the androgen signalling pathway.
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PMID:Effect of Leuprorelin Acetate on Cell Growth and Prostate-Specific Antigen Gene Expression in Human Prostatic Cancer Cells. 985 46

Four different genes were identified by immunoscreening of a cDNA expression library from the human prostate cancer cell line DU145 with allogeneic sera from four prostate cancer patients. A cDNA encoding the nucleolar protein No55 was further analysed and shown to be expressed at the mRNA level in several normal tissues, including ovaries, pancreas and prostate and in human prostate cancer cell lines PC-3, PC-3m and LNCaP. By reverse transcriptase/polymerase chain reaction, expression of No55 was several-fold higher in two out of nine prostate cancer primary tumours and two out of two metastatic lesions, compared to normal prostate tissue. Antibodies to No55 were detected in sera from seven out of 47 prostate cancer patients but not in sera from 20 healthy male controls. Sequence analysis of the No55 open reading frame from normal and tumour tissues revealed no tumour-specific mutations. The No55 gene was located to chromosome 17q21, a region reported to be partially deleted in prostate cancer. Considering the immunogenicity of the No55 protein in the tumour host, the expression profile and chromosomal localization of the corresponding gene, studies evaluating No55 as a potential antigen for immunological studies in prostate cancer may be warranted.
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PMID:Identification of nucleolar protein No55 as a tumour-associated autoantigen in patients with prostate cancer. 1095 78

Intrinsic and acquired antineoplastic drug resistance remain a major problem for advanced prostate cancer treatment. In order to characterize mechanisms of anti-neoplastic drug resistance in human prostate cancer cell lines, resistant sublines of four of the commonly studied prostate cancer cell lines (DU 145, PC-3, PPC-1, and TSU-PR1) were selected following exposure to increasing concentrations of doxorubicin (from 10-1000 nM). Sensitivity patterns of the parent and doxorubicin-resistant sublines to various anti-neoplastic drugs, including adriamycin, amsacrine, etoposide, camptothecin, vinblastine, vincristine, fluorodeoxyuridine, and melphalan, were determined using a sulforhodamine B growth inhibition assay. The expression of three well-described antineoplastic drug resistance proteins, P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and lung resistance protein (LRP), was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) assays specific for each of the mRNA species, and using immunocytochemical staining procedures specific for each of the polypeptides. All four of the doxorubicin-selected prostate cancer cell lines exhibited a multidrug resistance phenotype; administration of verapamil restored doxorubicin sensitivity for each of the drug resistant sublines. Although significant MDR1 expression was not detected in any of the parent cell lines before drug exposure by RT-PCR analysis or by immunocytochemistry, both MDR1 mRNA and P-gp protein were expressed by the TSU-PR1 Adr 1000 subline. In contrast, MRP mRNA and protein were present in each of the prostate cancer cell lines before doxorubicin-selection, and an increase in MRP expression appeared to accompany the acquisition of drug resistance in DU 145, PC-3, and PPC-1 doxorubicin-resistant sublines. LRP was variably expressed by each of the parent and resistant cell lines. These data suggest that drug resistance in human prostate cancer may be multifactorial, with MRP and LRP frequently expressed in prostate cancer cells before antineoplastic drug treatment and P-gp expression occasionally acquired after drug exposure.
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PMID:Doxorubicin-resistant variants of human prostate cancer cell lines DU 145, PC-3, PPC-1, and TSU-PR1: characterization of biochemical determinants of antineoplastic drug sensitivity. 1107 91

RET fused gene (RFG)/ELE1alpha/androgen receptor-associated protein 70(ARA70) was first found to be involved in the activation of the RET proto-oncogene in thyroid neoplasm and has recently been shown to be a ligand-dependent transcriptional coregulator for androgen receptor (AR). The functionality of RFG/ELE1alpha/ARA70 remains controversial, and little is known about factors regulating its expression in the prostate. Of significant interest is whether this molecule is involved in prostate carcinogenesis. Using reverse transcriptase-polymerase chain reaction semiquantitation, we compared RFG/ELE1alpha/ARA70 mRNA levels in four prostate cancer cell lines (LNCaP, TSU-Pr1, DU-145, and PC-3) with those found in primary cultures of normal prostatic epithelial cells (PrECs). In addition, we examined the effects of androgen and antiandrogen, estrogen and antiestrogen, and a demethylating agent on RFG/ELE1alpha/ARA70 mRNA expression levels in AR- and AR+ PC-3 cells. Reduced levels of RFG/ELE1alpha/ARA70 message were observed in all four prostate cancer cell lines when compared with normal PrECs in primary cultures. RFG/ELE1alpha/ARA70 mRNA levels in PC-3 cells, which express both estrogen receptor subtypes, were upregulated by 17beta-estradiol and inhibited by the antiestrogen ICI-182780. In PC-3(AR+) cells, which were genetically engineered to express AR, exposure to androgen upregulated RFG/ELE1alpha/ARA70 mRNA expression, whereas treatment with 4-hydroxyflutamide lowered expression of this transcript. Furthermore, treatment of DU-145 cells, which did not express RFG/ELE1alpha/ARA70 transcripts, with a demethylating agent reactivated transcription of this gene. Polymerase chain reaction analyses of monochromosomal human-rodent hybrid panels localized a putative RFG/ELE1alpha/ARA70 isoform on human chromosome 5q31.1-31.2. In summary, we identified sex hormones and DNA hypermethylation as regulators of RFG/ELE1alpha/ARA70 expression in prostate cancer cells. In addition, we found reduced levels of RFG/ELE1alpha/ARA70 expression in prostate cancer cell lines when compared with expression levels in normal PrECs in culture. These findings suggest that RFG/ELE1alpha/ARA70 may be involved prostate carcinogenesis and that it may serve as a key mediator of estrogen-androgen synergism.
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PMID:Expression of RFG/ELE1alpha/ARA70 in normal and malignant prostatic epithelial cell cultures and lines: regulation by methylation and sex steroids. 1125 59

The objective of this study was to study the expression of estrogen receptor-beta (ER-beta) in prostatic adenocarcinoma and correlate it with Gleason grade and clinical outcome. Immunohistochemical evaluation was performed on prostate needle biopsies from 53 patients (T1-T3pN0M0). ER-beta and ER-alpha transcripts were also studied by semiquantitative reverse transcriptase polymerase chain reaction in PC-3 and LNCaP prostate carcinoma cell lines. ERbeta was expressed in 93% of adenocarcinomas and was positively associated with primary Gleason grade (P = 0.028 for percentage of positive cells and P = 0.046 using a semiquantitative scale) and Gleason score (P = 0.010 for percentage of positive cells and P = 0.014 using a semiquantitative scale). ER-beta expression in the benign epithelium of prostates with adenocarcinoma was detected in 92% of cases and in the stroma in 47% of cases. A trend for longer time to treatment failure was noted for cases with low ER-beta expression after curatively intended radiotherapy (P = 0.082). PC-3, an aggressive prostate cancer cell line with invasive properties in nude mice, expressed higher levels of ER-beta than LNCaP, a nonmetastasizing cell line, whereas no difference for ER-alpha transcripts could be observed. Our findings suggest that ER-beta, as detected by PPG5/10 antibody, may have a role in the process of dedifferentiation of prostate adenocarcinomas, with higher levels present in less differentiated tumors.
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PMID:Prostate carcinoma expression of estrogen receptor-beta as detected by PPG5/10 antibody has positive association with primary Gleason grade and Gleason score. 1215 65

Somatostatin (SST) plays an important regulatory role in the physiological control of various organs including the prostate. Somatostatin receptors (SSTRs) and SST analogs are potential targets for prostate cancer treatment, especially since it has been shown that SST analogues are clinically effective in the treatment of advanced prostate cancer. The presence of SST containing neuroendocrine (NE) cells in the epithelium of the human prostate and their suggested role in the paracrine regulation of this gland prompted us to study the potential expression of somatostatin receptors (SSTRs) in human prostatic tissue and prostate cancer cell lines. Using the reverse transcriptase polymerase chain reaction (RT-PCR), we found the SSTR subtypes 1-3 in stromal cells and in prostate cancer cell lines LNCaP, PC-3 and DU 145. Immunohistochemical analysis of 27 radical prostatectomy specimens demonstrated the presence of hSSTR1 in a subpopulation of cancerous and NE cells, whereas hSSTR2 was found in the stroma, peritumoral blood vessels and tumor cells. Receptor subtype 3 was demonstrated to be present on the cell membrane of BPH and malignant areas. A strong immunoreaction (IR) of hSSTR4 was found in tumor cells, as compared with a less intense IR in adjacent BPH areas. Somatostatin receptor subtype 5 was not detectable. Western blot analysis revealed immunoreactive bands of molecular weight between 44-60 kDa. In summary, the present study clearly demonstrates the presence of hSSTR1-3 in tumoral and nontumoral epithelial cells as well as in the stromal compartment, whereas hSSTR4 was found to be confined to epithelial cells, and SSTR5 was not detectable.
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PMID:Localization and mRNA expression of somatostatin receptor subtypes in human prostatic tissue and prostate cancer cell lines. 1247 41


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