Prostaglandin E2 induces hypoxia-inducible factor-1alpha stabilization and nuclear localization in a human prostate cancer cell line

Hypoxia-induced up-regulation of vascular endothelial growth factor (VEGF) expression is a critical event leading to tumor neovascularization. Hypoxia stimulates hypoxia-inducible factor-1alpha (HIF-1alpha), a transcriptional activator of VEGF. Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the formation of prostaglandins (PGs) from arachidonic acid, is also induced by hypoxia. We reported previously that COX-2 inhibition prevents hypoxic up-regulation of VEGF in human prostate cancer cells and that prostaglandin E(2) (PGE(2)) restores hypoxic effects on VEGF. We hypothesized that PGE(2) mediates hypoxic effects on VEGF by modulating HIF-1alpha expression. Addition of PGE(2) to PC-3ML human prostate cancer cells had no effect on HIF-1alpha mRNA levels. However, PGE(2) significantly increased HIF-1alpha protein levels, particularly in the nucleus. This effect of PGE(2) largely results from the promotion of HIF-1alpha translocation from the cytosol to the nucleus. PGE(2) addition to PC-3 ML cells transfected with a GFP-HIF-1alpha vector induced a time-dependent nuclear accumulation of the HIF-1alpha protein. Two selective COX-2 inhibitors, meloxicam and NS398, decreased HIF-1alpha levels and nuclear localization, under both normoxic and hypoxic conditions. Of several prostaglandins tested, only PGE(2) reversed the effects of a COX-2 inhibitor in hypoxic cells. Finally, PGE(2) effects on HIF-1alpha were specifically inhibited by PD98059 (a MAPK inhibitor). These data demonstrate that PGE(2) production via COX-2-catalyzed pathway plays a critical role in HIF-1alpha regulation by hypoxia and imply that COX-2 inhibitors can prevent hypoxic induction of HIF-mediated gene transcription in cancer cells.

Prostaglandin E(2) stimulates prostatic intraepithelial neoplasia cell growth through activation of the interleukin-6/GP130/STAT-3 signaling pathway

Cyclooxygenase (COX)-2 expression and prostaglandin E(2) (PGE(2)) secretion are increased in prostatic intraepithelial neoplasia (PIN) and prostate cancer. PGE(2) biosynthesis by cyclooxygenase (COX)-2 plays a pivotal role in inflammation and carcinogenesis. One of the critical proinflammatory cytokines in the prostate is interleukin-6 (IL-6). We hypothesized that increased expression of COX-2, with resultant increased levels of PGE(2) in human PIN cells, activates the IL-6 signaling pathway. We demonstrate an autocrine upregulation of PGE(2) mediated by IL-6 in a human PIN cell line. We further demonstrate that PGE(2) stimulates soluble IL-6 receptor (sIL-6R) release, gp130 dimerization, Stat-3 protein phosphorylation, and DNA binding activity. These events, induced by PGE(2), lead to increased PIN cell growth. Treatment of PIN cells with a selective COX-2 inhibitor decreases cell growth. Finally, PGE(2)-stimulated PIN cell growth was abrogated by the addition of IL-6 neutralizing antibodies. These data provide mechanistic evidence that increased expression of COX-2/PGE(2) contributes to prostate cancer development and progression via activation of the IL-6 signaling pathway.

The role of cyclooxygenase-2 in prostate cancer

Cyclooxygenase-2 (COX-2) is the inducible isozyme of COX, a key enzyme in the conversion of arachidonic acid to prostaglandins and other eicosanoids. COX-2 is highly expressed in a number of human cancers and cancer cell lines, including prostate cancer. We studied the immunohistochemical expression of COX-2 in the human prostate gland. The enzyme is strongly expressed in smooth muscle cells of both the normal and cancerous prostate. Its expression in noncancerous epithelial cells is limited to the basal cell layer. In prostatic inflammation, luminal epithelial cells surrounded by lymphocytes are induced to express the enzyme. COX-2 is expressed in the epithelial cells of high-grade prostatic intraepithelial neoplasia and cancer. We have demonstrated that treatment of human prostate-cancer cell lines with a selective COX-2 inhibitor induces apoptosis both in vitro and in vivo. The in vivo results also indicate that the COX-2 inhibitor decreases tumor microvessel density and angiogenesis. COX-2 inhibitors can prevent the hypoxic upregulation of a potent angiogenic factor, vascular endothelial growth factor. These results indicate that COX-2 inhibitors may, therefore, serve as effective chemopreventive and therapeutic agents in cancer of the prostate.

Expression of cyclooxygenase-1 and cyclooxygenase-2 in the human prostate

OBJECTIVES

To determine the cell-specific expression of the two major isoforms of cyclooxygenase (COX-1 and COX-2) in human noncancerous and cancerous prostatic tissues.

METHODS

Thirty-one specimens of prostate carcinoma (CaP) and 10 specimens of benign prostatic hyperplasia (BPH) were stained with mouse antihuman COX-1 and COX-2 monoclonal antibodies. The stained specimens were analyzed both descriptively and in a semiquantitative manner by assigning an immunoreactive intensity score (0 to 4). The averaged results were compared for different histologic tissue types, including luminal and basal epithelium of BPH, the peripheral zone, high-grade prostatic intraepithelial neoplasia (PIN), and CaP of varying Gleason grades.

RESULTS

COX-1 expression in noncancerous prostatic tissue was seen predominantly in the basal epithelial cells of BPH (90% positive staining). COX-1 expression was minimal in noncancerous luminal epithelial cells (0% to 10%) but was upregulated in CaP (63% of CaP specimens). Strong COX-2 expression was demonstrated in the smooth muscle cells of the prostate. COX-2 was also expressed in the basal epithelial cells (60% BPH, 94% peripheral zone, 75% PIN). Luminal epithelial cells derived from BPH, the peripheral zone, and PIN expressed COX-2 in 0%, 26%, and 86% of samples, respectively. COX-2 expression in CaP was intense and uniform, with 87% of samples demonstrating immunoreactivity.

CONCLUSIONS

The results of the present study indicate that expression of both COX-1 and COX-2 in human CaP is increased. COX-2 expression is also increased in the basal and luminal epithelial cells of PIN. These data indicate that COX-1 and COX-2 (and/or their prostaglandin products) may play a role in the malignant transformation of the prostate.

Inhibition of cyclooxygenase-2 suppresses angiogenesis and the growth of prostate cancer in vivo

PURPOSE

Cyclooxygenase (COX)-2, an inducible enzyme which catalyzes the formation of prostaglandins from arachidonic acid, is expressed in prostate cancer specimens and cell lines. To evaluate the in vivo efficacy of a COX-2 inhibitor in prostate cancer, NS398 was administered to mice inoculated with the PC-3 human prostate cancer cell line.

MATERIALS AND METHODS

A total of 28 male nude mice were inoculated subcutaneously with 1 million PC-3 cells. Tumors were palpable in all 28 animals 1 week after inoculation and mice were randomized to receive either vehicle (control) or NS398, 3 mg./kg. body weight, intraperitoneally three times weekly for 9 weeks. Tumors were measured at weekly intervals. After a 10-week experimental period, mice were euthanized and tumors were immuno- histochemically assayed for proliferation (PCNA), apoptosis (TUNEL) and microvessel density (MVD) (Factor-VIII-related antigen). Tumor VEGF content was assayed by Western blotting.

RESULTS

NS398 induced a sustained inhibition of PC-3 tumor cell growth and a regression of existing tumors. Average tumor surface area from control mice was 285 mm.2 as compared with 22 mm.2 from treated mice (93% inhibition, p <0.001). Immunohistochemical analysis revealed that NS398 had no effect on proliferation (PCNA), but induced apoptosis (TUNEL) and decreased MVD (angiogenesis). VEGF expression was also significantly down regulated in the NS398-treated tumors.

CONCLUSIONS

These results demonstrate that a selective COX-2 inhibitor suppresses PC-3 cell tumor growth in vivo. Tumor growth suppression is achieved by a combination of direct induction of tumor cell apoptosis and down regulation of tumor VEGF with decreased angiogenesis

Immunohistochemical localization of cyclooxygenase-1 and cyclooxygenase-2 in the human fetal and adult male reproductive tracts

The first rate-limiting step in the conversion of arachidonic acid to PGs is catalyzed by cyclooxygenase (Cox). Two isoforms of Cox have been identified, Cox-1 (constitutively expressed) and Cox-2 (inducible form), which are the products of two different genes. In this study we describe the immunohistochemical localization of Cox-1 and -2 in the human male fetal and adult reproductive tracts. There was no Cox-1 expression in fetal samples (prostate, seminal vesicles, or ejaculatory ducts), and only minimal expression in adult tissues. There was no expression of Cox-2 in the fetal prostate. In a prepubertal prostate there was some Cox-2 expression that localized exclusively to the smooth muscle cells of the transition zone. In adult hyperplastic prostates, Cox-2 was strongly expressed in smooth muscle cells, with no expression in the luminal epithelial cells. Cox-2 was strongly expressed in epithelial cells of both fetal and adult seminal vesicles and ejaculatory ducts. The Cox-2 staining intensity in the fetal ejaculatory ducts during various times of gestation correlated with previously reported testosterone production rates by the fetal testis. These data indicate that Cox-2 is the predominant isoform expressed in the fetal male reproductive tract, and its expression may be regulated by androgens. The distinct cell type-specific expression patterns of Cox-2 in the prostate (smooth muscle) vs. the seminal vesicles and ejaculatory ducts (epithelium) may reflect the different roles of PGs in these tissues.

Inhibition of cyclooxygenase-2 suppresses angiogenesis and the growth of prostate cancer in vivo

PURPOSE

Cyclooxygenase (COX)-2, an inducible enzyme which catalyzes the formation of prostaglandins from arachidonic acid, is expressed in prostate cancer specimens and cell lines. To evaluate the in vivo efficacy of a COX-2 inhibitor in prostate cancer, NS398 was administered to mice inoculated with the PC-3 human prostate cancer cell line.

MATERIALS AND METHODS

A total of 28 male nude mice were inoculated subcutaneously with 1 million PC-3 cells. Tumors were palpable in all 28 animals 1 week after inoculation and mice were randomized to receive either vehicle (control) or NS398, 3 mg./kg. body weight, intraperitoneally three times weekly for 9 weeks. Tumors were measured at weekly intervals. After a 10-week experimental period, mice were euthanized and tumors were immuno- histochemically assayed for proliferation (PCNA), apoptosis (TUNEL) and microvessel density (MVD) (Factor-VIII-related antigen). Tumor VEGF content was assayed by Western blotting.

RESULTS

NS398 induced a sustained inhibition of PC-3 tumor cell growth and a regression of existing tumors. Average tumor surface area from control mice was 285 mm.2 as compared with 22 mm.2 from treated mice (93% inhibition, p <0.001). Immunohistochemical analysis revealed that NS398 had no effect on proliferation (PCNA), but induced apoptosis (TUNEL) and decreased MVD (angiogenesis). VEGF expression was also significantly down regulated in the NS398-treated tumors.

CONCLUSIONS

These results demonstrate that a selective COX-2 inhibitor suppresses PC-3 cell tumor growth in vivo. Tumor growth suppression is achieved by a combination of direct induction of tumor cell apoptosis and down regulation of tumor VEGF with decreased angiogenesis

Upregulation of vascular endothelial growth factor by cobalt chloride-simulated hypoxia is mediated by persistent induction of cyclooxygenase-2 in a metastatic human prostate cancer cell line

Upregulation of vascular endothelial growth factor (VEGF) expression induced by hypoxia is crucial event leading to neovascularization. Cyclooxygenase-2, an inducible enzyme that catalyzes the formation of prostaglandins (PGs) from arachidonic acid, has been demonstrated to be induced by hypoxia and play role in angiogenesis and metastasis. To investigate the potential effect of COX-2 on hypoxia-induced VEGF expression in prostate cancer. We examined the relationship between COX-2 expression and VEGF induction in response to cobalt chloride (CoCl2)-simulated hypoxia in three human prostate cancer cell lines with differing biological phenotypes. Northern blotting and ELISA revealed that all three tested cell lines constitutively expressed VEGF mRNA, and secreted VEGF protein to different degrees (LNCaP > PC-3 > PC3ML). However, these cell lines differed in the ability to produce VEGF in the presence of CoCl2-simulated hypoxia. CoCl2 treatment resulted in 40% and 75% increases in VEGF mRNA, and 50% and 95% in protein secretion by LNCaP and PC-3 cell lines, respectively. In contrast, PC-3ML cell line, a PC-3 subline with highly invasive, metastatic phenotype, exhibits a dramatic upregulation of VEGF, 5.6-fold in mRNA and 6.3-fold in protein secretion after treatment with CoCl2. The upregulation of VEGF in PC-3ML cells is accompanied by a persistent induction of COX-2 mRNA (6.5-fold) and protein (5-fold). Whereas COX-2 expression is only transiently induced in PC-3 cells and not affected by CoCl2 in LNCaP cells. Moreover, the increases in VEGF mRNA and protein secretion induced by CoCl2 in PC-3ML cells were significantly suppressed following exposure to NS398, a selective COX-2 inhibitor. Finally, the effect of COX-2 inhibition on CoCl2-induced VEGF production was reversed by the treatment with exogenous PGE2. Our data demonstrate that VEGF induction by cobalt chloride-simulated hypoxia is maintained by a concomitant, persistent induction of COX-2 expression and sustained elevation of PGE2 synthesis in a human metastatic prostate cancer cell line, and suggest that COX-2 activity, reflected by PGE2 production, is involved in hypoxia-induced VEGF expression, and thus, modulates prostatic tumor angiogenesis.

Androgens induce the expression of vascular endothelial growth factor in human fetal prostatic fibroblasts

Androgens are known to directly stimulate prostate cancer cell growth. We have previously reported that LNCaP prostate cancer cells were dependent upon stromal coinoculation for growth in nude mice and that the stromal cells secreted a potent angiogenic factor, vascular endothelial growth factor (VEGF), which stimulated tumor angiogenesis. Immunohistochemical staining localized VEGF expression primarily to the stromal cells of human fetal and adult hyperplastic prostates, with both stromal and epithelial cell VEGF expression in prostate cancer. In the present studies, we test the hypothesis that androgens, in addition to their direct effects on prostate epithelial cells, have indirect effects on these cells via up-regulation of stromal VEGF production and angiogenesis. Primary cultures of human prostate fetal fibroblasts were treated with dihydrotestosterone (DHT), and the effects on VEGF messenger RNA (mRNA) expression were determined by Northern blotting. DHT (10 nM) increased VEGF mRNA levels maximally after 2 h. Nuclear run-on transcription assays demonstrated a 2-fold increase in the VEGF transcription rate 2 h after the addition of DHT. VEGF mRNA stability was unaffected by DHT addition. VEGF protein levels were determined by enzyme-linked immunosorbent assay and were increased 2-fold 4 h after DHT addition. These data indicate that androgens increase VEGF transcription and secretion of biologically active VEGF from human prostatic stroma. Androgens, therefore, may indirectly enhance prostate growth via up-regulation of VEGF from the surrounding stroma.

NS398, a selective cyclooxygenase-2 inhibitor, induces apoptosis and down-regulates bcl-2 expression in LNCaP cells

Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the formation of prostaglandins and other eicosanoids from arachidonic acid, is constitutively expressed in LNCaP human prostate cancer cell line. To evaluate the potential role of COX-2 in prostate cancer, LNCaP cells were treated with NS398, a selective COX-2 inhibitor, and the effects on cell viability and apoptosis were determined. NS398 treatment induced apoptosis in LNCaP cells in a time- and dose-dependent fashion. Treatment with 100 microM NS398 caused a down-regulation in bcl-2 protein expression, followed by chromatin condensation, chromosomal DNA fragmentation, and changes in nuclear morphology detected by 4,6-diamidino-2-phenylindole staining, DNA fragmentation assay, and terminal deoxynucleotidyl transferase-mediated UTP-biotin nick end-labeling assay. In contrast, NS398 treatment had no effect on either cell viability or nuclear function and morphology in human fetal prostate fibroblasts. These results demonstrate that NS398 induces apoptosis in LNCaP cells but not in human fetal prostate fibroblasts, and that this induction is associated with a decreased level of bcl-2 protein.

Effect of testosterone administration on sexual behavior and mood in men with erectile dysfunction

This double-blind placebo controlled, cross-over study was carried out to assess the effect of testosterone administration on sexual behavior mood, and psychological symptoms in healthy men with erectile dysfunction. Biweekly injections of 200 mg of testosterone enanthate were given over a period of 6 weeks separated by a washout period of 4 weeks. Blood samples for hormonal assessment, behavioral and psychological ratings were obtained prior to each injection. Luteinizing hormone remained significantly depressed but circulating testosterone had returned to baseline levels by 2 weeks following each hormonal injection. The ejaculatory frequency during the testosterone phase was statistically higher than during the placebo phase. There were marked, although statistically nonsignificant, increases in median frequency of reported sexual desire, masturbation, sexual experiences with partner, and sleep erections during the testosterone period. Testosterone did not have demonstrable effects on ratings of penile rigidity and sexual satisfaction. Mood variables and psychological symptoms did not change following hormonal administration. Results suggest that androgen administration to eugonadal men with erectile dysfunction may activate their sexual behavior without enhancing erectile capacity and without effects on mood and psychological symptoms.

The role of sex steroids in the pathogenesis and maintenance of benign prostatic hyperplasia

BACKGROUND

It has long been suspected that sex steroids play a key role in the pathogenesis of benign prostatic hyperplasia (BPH). Prostatic diseases do not occur in males castrated before puberty or in males with heritable disorders of androgen production or action. Both estrogens and androgens have been shown to induce BPH in experimental animals.

METHODS

Clinical studies utilizing hormonal therapies to treat BPH were reviewed. Studies that used total medical castration therapy via the use of a long-acting gonadotropin-releasing hormone (GnRH agonist), partial androgen blockade via the use of the 5 alpha-reductase inhibitor finasteride, and estrogen blockade (via the use of aromatase inhibitors) were analyzed.

RESULTS AND CONCLUSIONS

Both the GnRH agonists and finasteride result in prostatic size reduction and alleviate symptoms in some patients. Both therapies are more effective in men with larger prostates (> 40 cc). Finasteride is less efficacious in terms of size reduction than the GnRH agonists but also has fewer side effects. To date, clinical trials with aromatase inhibitors have not yielded dramatic positive results in the treatment of BPH.

Bone extracellular matrix induces homeobox proteins independent of androgens: possible mechanism for androgen-independent growth in human prostate cancer cells

BACKGROUND

Differences in gene expression in prostate cells are believed to be secondary to epithelial-stromal interactions. We theorized that bone matrix may provide a fertile "soil" for prostate cancer by inducing androgen-dependent genes and allowing for androgen-independent growth.

METHODS

Human prostate cancer cells (LNCaP) were grown under different conditions and analyzed for differential expression of mRNA. LNCaP cells were grown in the presence of 10 nM dihydrotestosterone (DHT), on extracellular matrix (ECM) derived from bone cells (without exogenous DHT), and on plastic culture dishes without exogenous DHT. A differential display of mRNA produced by LNCaP cells grown in the above conditions was then analyzed.

RESULTS

Multiple unique transcripts were present in cells that were grown in the presence of DHT and on bone ECM (without exogenous DHT), but not on plastic culture dishes without exogenous DHT. Nine of these transcripts were then cloned and analyzed. Many (5/9) of these transcripts were found to contain multiple ATTA motifs in their corresponding 3'-untranslated regions. ATTA motifs have been shown to be homeobox protein-binding sites. Homeobox proteins and their target genes are thought to regulate cellular differentiation. Consistent with this, we demonstrated by reverse transcription polymerase chain reaction (PCR) that homeobox genes were differentially expressed in LNCaP cells when the cells were grown in the presence of DHT and on bone ECM (without exogenous DHT), but not on plastic culture dishes without exogenous DHT. Furthermore, we assayed LNCaP/fetal fibroblast chimeric tumors (n = 8) that were grown in male nude mice. Some of these tumors continued to grow in these mice despite treatment with surgical castration. In blinded studies, we were able to determine which tumor samples were androgen independent by their expression of homeobox genes. All samples that were androgen independent (n = 4) expressed the homeobox genes. Finally, gel retardation assay demonstrated that the homeobox proteins were able to bind to our cloned DNA sequences. Furthermore, footprinting analysis showed that the homeobox proteins bound to the ATTA motif in the 3'-region of our target DNA.

CONCLUSIONS

Bone ECM, in the absence of DHT, has the ability to regulate androgen-responsive genes. Furthermore, many of these genes contain homeobox binding sites and the expression of homeobox genes may itself be regulated by bone ECM. If so, this may partially explain the clinical observation that bone provides a fertile "soil" for prostate cancer growth and metastasis.

Lack of correlation between prostate-specific antigen density and prostatic shrinkage in response to finasteride therapy

We attempted to correlate prostate volume reduction in response to finasteride treatment with initial prostate-specific antigen (PSA) levels and PSA density in men with symptomatic benign prostatic hyperplasia (BPH). The average reductions in prostatic volume (transrectal ultrasonography) were 27% and 34% after 6 and 12 months of finasteride therapy, respectively. Serum PSA levels decreased by 45% (6 months) and 50% (12 months). There was a positive correlation between initial serum PSA values and initial prostate volumes (r = 0.57, P < 0.001). There was no correlation, however, between the initial serum PSA or PSA-density values and prostate volume reduction. These data indicate that initial serum PSA and PSA-density values are not predictive of the response to finasteride therapy in terms of prostate size reduction.

Immunohistochemical localization of steroid 5 alpha-reductase 2 in the human male fetal reproductive tract and adult prostate

The activity of the type 2 isozyme of steroid 5 alpha-reductase is crucial for normal development of the external genitalia and prostate in human males. We used immunohistochemistry to localize type 2 isozyme expression in the human male fetal reproductive tract and adult prostate. In fetal tissue, the stroma of the seminal vesicles, corpus cavernosum, corpus spongiosum, dorsal vein complex, scrotal skin, and prostate expressed the enzyme. In addition, the epithelial cells of the fetal urethra and proximal prostatic ducts stained positively. The type 2 isozyme could not be detected in epithelial cells of the fetal prostatic acini, seminal vesicles, prostatic utricle, ejaculatory ducts, epididymides, and Cowper's glands. Adult prostate specimens were derived from transurethral prostatectomies performed for benign prostatic hyperplasia. Enzyme expression in these benign prostatic hyperplasia samples localized to the stroma and epithelial cells of the urethra and proximal ducts. No staining was detected in the acinar (luminal and basal) epithelial cells. Double staining with an antismooth muscle actin antibody localized type 2 isozyme expression to the stromal fibroblast cells of the prostate. Double staining with an androgen receptor antibody localized AR expression to the acinar epithelial cells and stromal fibroblasts. These data indicate that 5 alpha-reductase type 2 is expressed throughout the developing male genitourinary tract and functions as both an autocrine and a paracrine mediator of growth and differentiation.

Pathogenesis and medical management of benign prostatic hyperplasia

Benign prostatic hyperplasia is an almost universal disorder of aging males. The disease is heterogeneous with respect to the histology, size, symptoms, and response to medical management. Current medical therapies are based upon the knowledge of the pathophysiology of the disease and include hormonal therapies and alpha(1)-adrenergic blockade. Although there are at present no prognostic indicators of response to therapy, future studies may help delineate those patients who will most benefit from the various forms of treatment.

Estrogen receptor messenger RNA expression in human benign prostatic hyperplasia: detection, localization, and modulation with a long-acting gonadotropin-releasing hormone agonist

We have analyzed human benign prostatic hyperplastic (BPH) tissue derived from eight radical prostatectomy specimens from patients with prostate cancer for the expression of the estrogen receptor (ER) messenger RNA. Four of the eight patients received a long-acting gonadotropin-releasing hormone agonist (GnRHa) for 4 months prior to surgery. An RNase protection assay utilizing six riboprobes spanning most of the ER protein-coding sequences demonstrated expression of the ER mRNA in human BPH tissue. A comparison of ER mRNA expression in four patients who had received 4 months pretreatment with the GnRHa vs. the four untreated patients suggested that there is upregulation of ER mRNA expression with the GnRHa treatment. The combined techniques of in situ hybridization and immunocytochemistry localized the ER mRNA expression to the prostatic basal epithelial cells and stroma. We conclude that ER mRNA is expressed in human BPH tissue and that this expression is modulated by treatment with a long-acting GnRH agonist.

Enhanced androgen sensitivity in serum-free medium of a subline of the LNCaP human prostate cancer cell line

The LNCaP-Fast Growing Colony (FGC) human prostate cancer cell line proliferates in response to the addition of dihydrotestosterone (DHT) 10(-10)-10(-8) M in charcoal-stripped serum-supplemented media. LNCaP-FGC cells will not attach or proliferate in serum-free conditions. LNCaP-FGC stock cultures were maintained in medium supplemented with 10% FBS and added DHT (10(-9) M) for > 25 passages (6 months). The resultant subline was designated as LNCaP-ss (supersensitive) because of its ability to attach in serum-free medium and to proliferate in response to very low levels of DHT. LNCaP-ss cells were grown in serum-free medium and proliferation assessed after 2, 3, 5, and 7 days' treatment with DHT. Significant enhancement of growth was demonstrated after 7 days' treatment with DHT over a wide range of concentrations (DHT 10(-15)-10(-7) M) with maximal stimulation (3 x control, p < .001) noted with DHT 10(-14) M. Changing the medium during the course of the experiment decreased, but did not eliminate, the DHT-induced cellular proliferation. Scatchard analysis of binding studies with LNCaP-ss cells revealed that both the Kd for the androgen receptor (AR) and the number of AR sites/cell were similar to the corresponding values reported for the parental line. AR mRNA levels in LNCaP-ss cells, as measured by RNase protection assay, were significantly down-regulated by 7 days' treatment with DHT 10(-15), 10(-13), and 10(-9) M.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of androgen, estrogen, and growth factors on the proliferation of cultured fibroblasts derived from human fetal and adult prostates

Stromal enlargement plays a key role in the development of benign prostatic hypertrophy in humans. Human prostatic fibroblasts were obtained from fetal and adult prostates and characterized as to their androgen and estrogen receptor status and growth in response to dihydrotestosterone (DHT), estradiol (E2), hydroxyflutamide (OH-FLU), hydrocortisone, basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF). In addition, the ability of hormones and growth factors to induce the messenger RNA (mRNA) for the c-fos protooncogene was assessed as a measure of the early, direct effects of these compounds on cellular proliferation. Nuclear androgen receptors were demonstrable by immunocytochemistry in both fetal and adult cells. Nuclear estrogen receptor staining was negative. Neither E2 nor hydrocortisone increased cellular proliferation. Both EGF and bFGF did increase cellular growth. DHT (10(-8)-10(-7) M) had a significant stimulatory effect on cell growth only in serum-free media. OH-FLU addition enhanced DHT induced proliferation. Changing the media during the course of the experiment obliterated the stimulatory effect of DHT. Both EGF (10 ng/ml) and bFGF (20 ng/ml) increased the mRNA for the c-fos protooncogene. DHT (10(-7) M) did not induce the mRNA for c-fos. We conclude that EGF, bFGF, and DHT (especially in combination with OH-FLU) increase the proliferation of human prostatic fetal and adult fibroblasts in vitro. E2 has no effect on fibroblast proliferation. The stimulatory effects of EGF and bFGF are direct, whereas the effect of DHT appears to be indirect, possibly mediated via the increased production and/or secretion of growth factors.

Effect of the addition of estrogen to medical castration on prostatic size, symptoms, histology and serum prostate specific antigen in 4 men with benign prostatic hypertrophy

A total of 4 men with benign prostatic hypertrophy who underwent medical castration therapy with a long-acting gonadotropin-releasing hormone agonist (leuprolide) for more than 6 months elected to add an estrogen transdermal patch (0.05 mg. to the skin biweekly) to the leuprolide regimen. The average prostatic size (transrectal ultrasound), serum prostate specific antigen (PSA) levels and symptoms of prostatism were dramatically decreased with leuprolide alone. The addition of estrogen for 6 months did not result in any change in prostate size, symptoms or serum PSA levels over that seen with leuprolide alone. The development of squamous metaplasia was noted in 1 man with leuprolide alone and in 1 man after the addition of estrogen. Immunohistochemical staining with anticytokeratin 903 antibodies reveals that squamous metaplasia appears to arise from prostatic basal cells. We postulate that the target cell for estrogen action in the prostate is the prostatic basal cell. In the absence of androgen the only direct effect of estrogens is the induction of squamous metaplasia.

Effect of long-acting gonadotropin-releasing hormone analog (leuprolide) therapy on prostatic size and symptoms in 15 men with benign prostatic hypertrophy

To determine the effects of reversible medical castration on prostatic size and symptoms we treated 15 patients with benign prostatic hypertrophy with a long-acting GnRH analog, leuprolide (1 mg/day sc), for a minimum of 4 months. The men's serum testosterone, dihydrotestosterone, and estradiol concentrations fell to very low levels within 4-6 weeks after the initiation of treatment. Transrectal ultrasonography of the prostate demonstrated an average shrinkage of 40% after 4 months of treatment (n = 15) and 46% after 6 months of treatment (n = 11). All 15 men had improvement in urinary flow and, to a lesser extent, in nocturia and frequency. The side-effects of the therapy were decreased potency and flushing. The most dramatic improvement occurred in 4 of the 5 men who had complete urinary obstruction before treatment. One man had a suprapubic cystotomy tube removed during the fifth treatment month. Two other men who had Foley catheters before treatment are voiding well without catheters since their third treatment month. Another man who had a very large prostate (300 g) before treatment had one successful voiding trial, although he still has a suprapubic cystotomy tube. One man decided to stop treatment after 6 months. Two months later his hormone values and prostate size had returned to pretreatment levels. One man treated during the fourth and fifth months with fluoxymesterone in addition to leuprolide had regrowth of his prostate while receiving this androgen. We conclude that leuprolide treatment of men with benign prostatic hypertrophy results in shrinkage of prostatic size and concomitant improvement in the obstructive symptoms of prostatism. The prostatic shrinkage reverses when treatment is discontinued or combined with androgen.