mibolerone and Adenocarcinoma

To identify the androgen-responsive genes in prostate and screen the molecular targets for further studying human prostate cancer.. The potential androgen-responsive gene pituitary tumor transforming gene 1 (PTTG1) was selected which had been previously screened by cDNA microarray in rat prostate and its mRNA level was detected by Northern blot in the castrated rat prostate with and without replacement of Mibolerone. Immunohistochemistry was performed to determine the expression and location of PTTG1 in human prostate tissues. Then human androgen-dependent prostate cancer cells LNCaP were used as a model to study the regulation of PTTG1 by Mibolerone.. PTTG1 mRNA was hardly detectable in the prostate of 7-day castrated rats, while it was up-regulated dramatically in the prostate of 7-day castrated rats treated with Mibolerone for 2 days. It was showed that high expression of PTTG1 was localized to the epithelial cells of human prostate cancer but not to the stromal cells with Immunohistochemistry. Northern blot analysis indicated that LNCaP cells treated with 0.1 nmol/L Mibolerone for 2 days led to the high PTTG1 mRNA expression. The basic expression of PTTG1 in human androgen-independent prostate cancer cell lines PC3 or DU145 was even higher than that in the human androgen-dependent prostate cancer cells LNCaP treated with Mibolerone.. Androgen can up-regulate the PTTG1 expression in castrated rat prostate and human prostate cancer cell LNCaP. It suggests that PTTG1 is potential to play an important role in human prostate cancer progression.

Topics: Adenocarcinoma; Animals; Blotting, Northern; Cell Line, Tumor; Gene Expression; Humans; Immunohistochemistry; Male; Nandrolone; Neoplasm Proteins; Orchiectomy; Prostate; Prostatic Neoplasms; Rats; Rats, Sprague-Dawley; RNA, Messenger; Securin; Testosterone Congeners

Peroxisome proliferator-activated receptor (PPAR) alpha is a member of the nuclear receptor superfamily of ligand-activated transcription factors. PPARalpha is activated by peroxisome proliferators and fatty acids and has been shown to be involved in the transcriptional regulation of genes involved in fatty acid metabolism. In rodents, the PPARalpha-mediated change in such genes results in peroxisome proliferation and can lead to the induction of hepatocarcinogenesis. Using the mRNA differential display technique and Northern blot analysis, we have shown that chronic exposure of the prostate cancer epithelial cell line LNCaP to the synthetic androgen mibolerone results in the down-regulation of PPARalpha mRNA. Levels of PPARalpha mRNA are reduced to approximately 40% of control levels in LNCaP cells exposed to 10 nM mibolerone for 96 h. PPARalpha-responsive reporter plasmids derived from human ApoA-II and muscle carnitine palmitoyl-transferase I genes were stimulated by the PPARalpha-activating ligand Wy-14,643 in LNCaP cells. In situ hybridization and immunohistochemical analyses showed that PPARalpha expression in prostate is confined to epithelial cells. In benign prostatic tissue, PPARalpha mRNA was either absent or only weakly expressed in the basal epithelial cells. In 11 of 18 (61%) poorly differentiated (Gleason score, 8-10) prostatic carcinoma specimens, there was strong expression of PPARalpha compared with 4 of 12 Gleason score 7 tumors and 2 of 11 Gleason score 3-6 tumors (P < 0.01). These results suggest that PPARalpha is found and functional in human prostate and is down-regulated by androgens. The role of PPARalpha may be to integrate dietary fatty acid and steroid hormone signaling pathways, and its overexpression in advanced prostate cancer may indicate a role in tumor progression with the potential involvement of dietary factors.

Topics: Adenocarcinoma; Androgens; Blotting, Northern; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; In Situ Hybridization; Male; Nandrolone; Prostate; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Testosterone Congeners; Transcription Factors; Tumor Cells, Cultured

Currently, no curative therapy for metastatic prostate cancer exists. Causing prostate cancer cells to express functionally active sodium iodide symporter (NIS) would enable those cells to concentrate iodide from plasma and might offer the ability to treat prostate cancer with radioiodine. Therefore, the aim of our study was to achieve tissue-specific expression of full-length human NIS (hNIS) cDNA in the androgen-sensitive human prostatic adenocarcinoma cell line LNCaP and in subcell lines C4, C4-2, and C4-2b in vitro. For this purpose, an expression vector was generated in which full-length hNIS cDNA coupled to the prostate-specific antigen (PSA) promoter has been ligated into the pEGFP-1 vector (NIS/PSA-pEGFP-1). The PSA promoter is responsible for androgen-dependent expression of PSA in benign and malignant prostate cells and was therefore used to mediate androgen-dependent prostate-specific expression of NIS. In addition, two control vectors were designed, which consist of the pEGFP-1 vector containing the PSA promoter without NIS cDNA (PSA-pEGFP-1) and NIS cDNA without the PSA promoter (NIS-pEGFP-1). Prostate cancer cells were transiently transfected with each of the above-described expression vectors, incubated with or without androgen (mibolerone) for 48 h, and monitored for iodide uptake activity. In addition, stably transfected LNCaP cell lines were established for each vector. Prostate cells transfected with NIS/PSA-pEGFP-1 showed perchlorate-sensitive, androgen-dependent iodide uptake in a range comparable to that observed in control cell lines transfected with hNIS cDNA. Perchlorate-sensitive iodide uptake was not observed in cells transfected with NIS/PSA-pEGFP-1 and treated without androgen or in cells transfected with the control vectors. In addition, prostate cancer cell lines without PSA expression (PC-3 and DU-145) did not show iodide uptake activity when transfected with NIS/PSA-pEGFP-1. Western blotting of LNCaP and C4-2b cell membranes transfected with NIS/PSA-pEGFP-1 using a monoclonal antibody that recognizes the COOH-terminus of hNIS revealed a band with a molecular weight of 90,000 that was not detected in androgen-deprived cells or in cells transfected with the control vectors, as well as a minor band at Mr 150,000 in transiently transfected LNCaP cell membranes. In conclusion, tissue-specific androgen-dependent iodide uptake activity has been induced in prostate cancer cells by PSA promoter-directed NIS expression. This study r

Topics: Adenocarcinoma; Androgens; Carrier Proteins; Cell Membrane; DNA, Complementary; Gene Expression Regulation, Neoplastic; Genetic Vectors; Humans; Iodides; Male; Membrane Proteins; Nandrolone; Neoplasms, Hormone-Dependent; Organ Specificity; Prostate-Specific Antigen; Prostatic Neoplasms; Recombinant Fusion Proteins; Symporters; Transfection; Tumor Cells, Cultured

In addition to modulation of cell proliferation and stimulation of prostate-specific antigen secretion, one of the most striking effects of androgens on the human prostate cancer cell line LNCaP is the accumulation of neutral lipids. These lipids are synthesized de novo, suggesting that LNCaP cells express all enzymes required for endogenous lipogenesis and that the expression and/or activity of some of these enzymes is affected by androgens. One of the key enzymes involved in lipogenesis is fatty acid synthase (FAS), a potential prognostic enzyme and therapeutic target that is found to be frequently overexpressed in a variety of cancers including prostate cancer. Here, using Northern blot analysis, the gene encoding FAS is shown to be abundantly expressed in LNCaP cells and in two other prostate cancer cell lines tested (PC-3 and DU-145). In LNCaP cells, androgen treatment (10(-8) M R1881) causes a 3-4-fold increase in FAS mRNA levels. Concomitantly with the increase in FAS gene expression, androgens induce a 10-12-fold stimulation of FAS activity. Effects are dose- and time-dependent and follow courses similar to those of the androgen induction of lipid accumulation. In support of the involvement of the androgen receptor, steroid specificity of regulation of FAS activity is in agreement with the aberrant ligand specificity of the mutated androgen receptor in LNCaP cells. Stimulation of FAS activity is inhibited by the antiandrogen Casodex (bicalutamide) and is absent in the androgen receptor-negative cell lines PC-3 and DU-145. Taken together, these data demonstrate that androgens, mediated by the androgen receptor, stimulate the expression and activity of FAS and suggest that stimulation of FAS activity represents at least part of the mechanism by which androgens induce the accumulation of neutral lipids in LNCaP cells.

Topics: Adenocarcinoma; Androgen Antagonists; Androgens; Anilides; Dihydrotestosterone; Dose-Response Relationship, Drug; Enzyme Induction; Fatty Acid Synthases; Gene Expression Regulation, Neoplastic; Humans; Lipids; Male; Metribolone; Nandrolone; Neoplasm Proteins; Nitriles; Prostatic Neoplasms; Receptors, Androgen; Testosterone; Testosterone Congeners; Tosyl Compounds; Tumor Cells, Cultured

To study the mechanisms by which androgens intervene in the regulation of growth and differentiation of human prostatic epithelial cells, cDNA clones encoding putative prostate-secreted proteins were characterized and tested as potential markers for androgen action. One of the isolated cDNAs expressed diazepam-binding inhibitor/acyl-CoA-binding protein (DBI/ACBP), suggesting that this polypeptide, that has been implicated in a large number of biochemical processes, is expressed and secreted by prostate cells. As demonstrated by Northern blot analysis, the mRNA encoding DBI/ACBP was expressed in prostate tissue and in the three human prostatic adenocarcinoma cell lines tested: LNCaP, PC-3 and DU-145. In androgen-sensitive LNCaP cells, the synthetic androgen R1881 stimulated the DBI/ACBP steady state mRNA levels with half maximal effects at a concentration of 0.2 nM. Increases were a maximal 12 h after addition of the synthetic hormone. DBI/ACBP mRNA levels could also be stimulated by the synthetic androgen mibolerone and by the natural androgens testosterone and dihydrotestosterone. In agreement with the altered steroid specificity of the androgen receptor in LNCaP cells, estradiol and progesterone also exerted a stimulatory effect. Cortisol and the synthetic glucocorticoid dexamethasone were without effect. Androgen stimulation of DBI/ACBP mRNA levels was abolished in the presence of the protein synthesis inhibitor cycloheximide, implying a role for labile or androgen-induced proteins in this androgen stimulation. This is in contrast to the androgen stimulation of the mRNA encoding prostate-specific antigen (PSA), suggesting that different mechanisms are involved in the androgen regulation of these two genes. Although further experiments are required to confirm that DBI/ACBP is secreted by prostatic epithelial cells, these data demonstrate that the mRNA encoding DBI/ACBP is expressed in prostate cells and is affected by androgens in androgen-responsive LNCaP cells.

Topics: Adenocarcinoma; Androgens; Blotting, Northern; Carrier Proteins; Cloning, Molecular; Cycloheximide; Diazepam Binding Inhibitor; Dihydrotestosterone; DNA, Complementary; Humans; Immune Sera; Male; Metribolone; Nandrolone; Prostate; Prostate-Specific Antigen; Prostatic Neoplasms; RNA, Messenger; Testosterone; Tumor Cells, Cultured