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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of androgens, antiandrogens, and other steroid hormones on growth of the human prostate cancer cell line LNCaP were studied. Despite the absence of receptors for progesterone and estradiol, the growth rate of the androgen responsive LNCaP-FGC cells increased when cultured in the presence of either estrogens or progestagens. In addition, most antiandrogens were also growth stimulators. This aberrant response was due to a threonine to alanine substitution at amino acid position 868 in the steroid binding domain of the androgen receptor (AR). Only the antiandrogen ICI 176,334 could block transcription and cell growth by the mutant receptor. By immunoprecipitation of the AR from LNCaP cells with the specific antibody F39.4.1 and Western blotting, three types of heat-shock proteins co-precipitated: hsp90, hsp70 and hsp56. This co-isolation could be prevented by pre-incubating the cells with androgens or with the antiandrogen hydroxyflutamide. Only the antiandrogen ICI 176,334 could block the effect of androgens on complex dissociation and prevent tight nuclear binding of the AR. Hydroxyflutamide could only inhibit tight nuclear binding of the wild-type AR. Therefore, in LNCaP cells the mutation in the steroid binding domain of the AR prevents a blockade of receptor function by most antiandrogens, but not by ICI 176,334, probably because of a different mechanism by which this compound blocks receptor function.
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PMID:Studies on the human prostatic cancer cell line LNCaP. 804 98

The efficacy of Casodex (ICI 176,334; Zeneca Pharmaceuticals, Macclesfield, UK), a nonsteroidal antiandrogen, in the treatment of advanced prostate cancer has been compared in two trials with castration, either surgical (bilateral orchitectomy) or medical, with the gonadotropin-releasing hormone agonist Zoladex (goserelin acetate; Zeneca Pharmaceuticals). The half-life of Casodex is 7 to 10 days, and allows once-daily dosing. The first trial was a prospective, randomized study involving 150 patients receiving Casodex, 50 mg once daily p.o., and 154 patients undergoing castration. There were no significant differences between the two groups in subjective responses, time to treatment failure, or time to objective evidence of disease progression. The other study involved higher doses, the dose being selected after patients had received one of two doses of Casodex, 100 mg/day or 150 mg/day, in a double-blind study. On statistical analysis, it was clear that the higher dose was more effective, and thus most patients taking 100 mg/day were switched to 150 mg/day. Again, Casodex treatment was compared with medical or surgical castration. The higher dose of Casodex is well tolerated with a similar adverse event profile as the lower dose of 50 mg/day. Follow-up is as yet too short for an analysis of efficacy.
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PMID:Current clinical studies with a new nonsteroidal antiandrogen, Casodex. 817 13

Casodex (Bicalutamide, ICI 176,334) is a potent, non-steroidal, selective anti-androgen with a long half-life allowing once-daily oral administration. In this randomised, open, multicentre study, Casodex 50 mg monotherapy was compared with castration (medical, using goserelin acetate, [Zoladex], or surgical) in 245 patients with advanced prostate cancer. Primary end-points were time to treatment failure, time to objective progression and survival. Subjective responses, quality of life and tolerability were also evaluated. There was no significant difference between the groups in terms of objective progression or subjective responses. Treatment failed in 59 of 119 patients (50%) randomised to Casodex and in 61 of 126 patients (48%) randomised to castration (no statistically significant difference). An updated analysis showed that survival was similar in the two groups. Casodex was well tolerated with a low incidence of diarrhoea and sexual dysfunction. On the basis of this study, Casodex monotherapy is an effective alternative to castration in the treatment of metastatic prostate cancer.
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PMID:A randomised comparison of monotherapy with Casodex 50 mg daily and castration in the treatment of metastatic prostate carcinoma. Casodex Study Group. 853 75

We have studied the response to oestrogen and expression of oestrogen receptors in responsive LNCaP and androgen non-responsive PC3 human prostate cancer cell lines. Growth of LNCaP cells is significantly stimulated by physiological concentrations of oestradiol; this growth increase appears to be comparable to that induced by either testosterone or dihydrotestosterone. In contrast, oestradiol significantly inhibits the proliferation of PC3 cells. We also present novel evidence for functional oestrogen binding in LNCaP cells. This evidence was first obtained by means of radioligand binding assays and was further corroborated using: (a) immunocytochemical analysis of oestrogen and progesterone receptors; (b) reverse transcriptase polymerase chain reaction of oestrogen receptor mRNAs; and (c) immunofluorescence of the 27 kDa heat shock protein (Hsp27), which has been reported to be a marker of functional oestrogen receptors. There appeared to be significantly and consistently lower levels of oestrogen receptor expressed in PC3 cells than in LNCaP cells. The observation that oestradiol-induced growth of LNCaP cells is completely reversed by the pure anti-oestrogen ICI 182,780 clearly implies that the biological response of these cells to oestradiol is mediated mainly via its own receptor. On the other hand, use of a neutralizing antibody against transforming growth factor (TGF)-beta 1 results in a remarkable increase in the growth of PC3 cells; this effect is almost completely abolished after the addition of oestradiol. This suggests that the oestradiol-induced growth inhibition may be mediated by TGF-beta 1. These results suggest that the current model for hormone-dependence of human prostatic carcinoma should be revised. This is of special concern, because recent data indicate that prostate cancer has become the most prevalent cancer and the second principal cause of cancer death in western countries.
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PMID:Human prostate cancer: a direct role for oestrogens. 858 3

The effect of Casodex (ICI 176,334), a new, once-daily, selective antiandrogen, given as 50 mg monotherapy, was compared with orchidectomy in a randomised, multicentre, open study in 376 patients with metastatic prostate cancer. At 3 months, PSA was reduced by 86% in the Casodex group and by 96% in the orchidectomy group. Treatment failed in 51 patients in the orchidectomy group and 66 showed a subjective response. Treatment failed in 86 patients treated with Casodex and 40 patients showed a subjective response. Patients treated with Casodex maintained their sexual interest better than those in the orchidectomy group. Median survival was significantly longer in the orchidectomy group. Casodex was well-tolerated. The most likely reason for the differences between the groups regarding time to treatment failure and survival is that the dose of Casodex was too small. Further studies with higher doses of Casodex are in progress.
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PMID:Randomised study of Casodex 50 MG monotherapy vs orchidectomy in the treatment of metastatic prostate cancer. The Scandinavian Casodex Cooperative Group. 873 52

The aim of the current study is to demonstrate normal and malignant prostatic epithelial cells (PrECs) as targets for receptor-mediated estrogenic and antiestrogenic action. Using an improved protocol, we have successfully isolated and maintained highly enriched populations of normal PrECs from ultrasound-guided peripheral zone biopsies, individually determined to be morphologically normal. Semiquantitative reverse transcription-PCR analyses were used to determine whether transcripts of estrogen receptor (ER)-alpha and those of ER-beta were expressed in our normal PrEC primary cultures, in a commercially available PrEC preparation (PrEC; Clontech), in an immortalized PrEC line established from a benign prostatic hyperplasia specimen (BPH-1), and in three prostatic cancer cell lines (LNCaP, PC-3, and DU145). Expression levels of ER-alpha and ER-beta transcripts were related to those of two estrogen-responsive genes [progesterone receptor (PR) and pS2], at the message levels, to gain insights into the functionality of the ER subtypes in PrECs. Interestingly, only transcripts of ER-beta, but not those of ER-alpha, were found in our primary cultures of normal PrECs, along with both PR and pS2 mRNA. These data strongly suggest that estrogen action was signaled exclusively via ER-beta in normal human PrECs. In contrast, PrEC (Clontech) and BPH-1 cells expressed both ER-alpha and ER-beta transcripts and no PR nor pS2 mRNA in PrEC and only a minimal level of PR mRNA in BPH-1. Among the three prostate cancer cell lines, LNCaP expressed ER-beta mRNA along with transcripts of PR and pS2, DU145 expressed messages of ER-beta and PR, and PC-3 cells exhibited ER-alpha, ER-beta, and pS2 mRNA. Thus, unlike normal PrECs, expression patterns of these genes in malignant PrECs are more variable. Treatment of prostate cancer cells with demethylation agents effectively reactivated the expression of ER-alpha mRNA in LNCaP and DU145 and that of pS2 message in DU145. These findings provide experimental evidence that ER-alpha gene silencing in prostate cancer cells, and perhaps also in normal PrECs, are caused by DNA hypermethylation. To evaluate the potential of using antiestrogens as prostate cancer therapies, we have assessed the growth-inhibitory action of estrogens (estradiol and diethylstilbestrol) and antiestrogens (4-hydroxy-tamoxifen and ICI-182,780) on PC-3 and DU-145 cells. In PC-3 cells, which express both ER subtypes, estrogens as well as antiestrogens are effective inhibitors. In contrast, in DU145 cells, which express only ER-beta, antiestrogens, but not estrogens, are growth inhibitors. By comparison, ICI 182,780 is the more effective cell growth inhibitor. Importantly, the ICI 182,780-induced antiproliferative effects were reversed by cotreatment of DU145 cells with an ER-beta antisense oligonucleotide, hence lending additional support to a central role played by ER-beta in mediating growth-inhibitory action of antiestrogens.
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PMID:Expression of estrogen receptor (ER)-alpha and ER-beta in normal and malignant prostatic epithelial cells: regulation by methylation and involvement in growth regulation. 1086 8

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

Ca2+ regulation of Cl- current induced by cell swelling (I(CI,swell)) in response to hypotonicity was studied in human prostate cancer epithelial cells (LNCaP) by using the patch-clamp technique. Increase of global intracellular Ca2+ ([Ca2+]in) to 1 mM as well as variations of the extracellular Ca2+ ([Ca2+]out) in the 0 to 10 mM range did not affect time course of the development, maximal amplitude, rectification properties, and kinetics of I(CI,swell). However, the presence of 0.1 mM thapsigargin (TG), an inhibitor of endoplasmic reticulum (ER) Ca2+ pump, resulted in a more than 50% inhibition of ICI,swell. The blockade of plasma membrane store-operated channels (SOCs), activated in the presence of TG, by 2 mM Ni2+ prevented TG-conferred I(CI,swell) inhibition by extracellular Ca2+. In the presence of TG and Ca2+, the cells failed to exhibit regulatory volume decrease. We conclude that interaction between volume-regulated anion channels (VRACs) carrying I(CI,swell) and Ca2+ occurs in the microdomains from the inner surface of the membrane that are not accessible to the changes in [Ca2+]in, but can be readily reached by Ca2+ entering the cell via plasma membrane, especially through SOCs. Preferred access of SOC-transported Ca2+ to VRAC suggests colocalization of these channels in the cell membrane.
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PMID:Ca2+ modulation of volume-regulated anion channels: evidence for colocalization with store-operated channels. 1174 19

Housing adult rats on ground corncob bedding impedes male and female mating behavior and causes acyclicity in females. The suppressive effects on ovarian cyclicity are mimicked by a mitogenic agent purified from the ground corncob bedding material (corn mitogen; CM), which stimulates the proliferation of estrogen receptor (ER)-positive (MCF-7 cells) and ER-negative (MDA-MD-231 cells) breast cancer cells. Purified CM does not compete for [(3)H]estradiol binding to ER or nuclear type II sites, and its effects on MCF-7 breast cancer cell proliferation are not blocked by the antiestrogen ICI-182,780. These results suggest that the active component is unlikely to be a phytoestrogen, bioflavonoid, mycotoxin, or other known endocrine-disrupting agent that modifies cell growth via ER or type II [(3)H]estradiol binding sites. CM also stimulates the proliferation of PC-3 human prostatic cancer cells in vitro, and the growth rate of PC-3 cell xenografts is accelerated in nude male mice housed on ground corncob as opposed to pure cellulose bedding. Consequently, this endocrine-disrupting agent in ground corncob bedding may influence behavioral and physiologic reproductive response profiles and malignant cell proliferation in experimental animals. Fresh corn (kernels and cob) or corn tortillas also contain CM, indicating that human exposure is likely; consequently, CM and/or related mitogens in corn products may influence human health and development.
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PMID:A novel endocrine-disrupting agent in corn with mitogenic activity in human breast and prostatic cancer cells. 1452 57

Goserelin acetate is a LH-RH agonist developed by AstraZeneca (formerly ICI, UK), and has been used clinically for the treatment of prostate cancer as a 4-week controlled-release formulation (Zoladex 3.6 mg depot). Recently, a new drug (Zoladex LA 10.8 mg depot) with 3-month controlled-release formulation was developed and became commercially available in Japan. In the randomized comparative phase III studies carried out with global bases, single administration of the new drug yielded almost equivalent anti-testosterone effect and the same serum level of the previous 3.6 mg depot formulation in 3-times continuous administration. In these studies, adverse drug reactions, which were mainly due to pharmacological effects of the new drug and minimal, were found in 52.6% (41/78) compared with 54.8% (46/84) with the previous 3.6 mg depot formulation. In the phase III studies, there were no significant differences in average serum testosterone levels between the two formulations at 12 and 13 weeks after administration. In the Japanese late phase II study with untreated patients, castration effect was observed in all 20 cases entered in the trial. In 20 cases in which treatment was switched from 3.6 mg depot to the new formulation, there were no significant changes in serum testosterone levels at castration level of the untreated patients, 90% (18/20) responded to the treatment, and normalization of PSA level was found in 75.0% (15/20). The adverse drug reactions were mainly increased triglyceride level and hot flushes. In the retrospective evaluation of untreated patients in this trial and the post-marketing clinical trial data for 3.6 mg depot, it was concluded that the new drug had almost the same efficacy and safety profile as 3.6 mg depot in Japanese people. These results indicate that Zoladex LA 10.8 mg depot has the same efficacy and safety as 3.6 mg depot with administration every three months, the burden of injection of LH-RH agonist can be reduced. This new medication can be considered a new standard for treatment of prostate cancer.
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PMID:[A new LH-RH agonist for treatment of prostate cancer, 3-month controlled-release formulation of goserelin acetate (Zoladex LA 10.8 mg depot)--outline of pre-clinical and clinical studies]. 1235 59


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