Presence Of Finasteride Research Articles

Sexual dimorphism following in vitro ischemia in the response to neurosteroids and mechanisms of injury

BackgroundCerebral ischemic stroke is a significant cause of morbidity and mortality. Sex differences exist following stroke in terms of incidence, symptoms, outcomes and response to some treatments. Importantly, molecular mechanisms of injury, activated following ischemia may differ between the sexes and if so may account, at least in part, for sex differences seen in treatment response. Here we aimed to determine, using single-sex organotypic hippocampal slice cultures, whether the effectiveness of a potential treatment option, i.e. sex steroids, exhibited any sexual dimorphism and whether sex affected the mechanisms of apoptosis activated following ischemia.ResultsFollowing exposure to ischemia, male-derived tissue exhibited higher levels of cell death than female-derived tissue. Various sex steroid hormones, i.e. progesterone, allopregnanolone, and estradiol, were protective in terms of reducing the amount of cell death in male- and female-derived tissue whereas medoxyprogesterone acetate (MPA) was only protective in female-derived tissue. The protective effect of progesterone was abolished in the presence of finasteride, a 5α-reductase inhibitor, suggesting it was largely mediated via its conversion to allopregnanolone. To test the hypothesis that sex differences exist in the activation of specific elements of the apoptotic pathway activated following ischemia we administered Q-VD-OPH, a caspase inhibitor, or PJ34, an inhibitor of poly (ADP ribose) polymerase (PARP). Caspase inhibition was only effective, in terms of reducing cell death, in female-derived tissue, whereas PARP inhibition was only protective in male-derived tissue. However, in both sexes, the protective effects of progesterone and estradiol were not observed in the presence of either caspase or PARP inhibition.ConclusionsSex differences exist in both the amount of cell death produced and those elements of the cell death pathway activated following an ischemic insult. There are also some sex differences in the effectiveness of steroid hormones to provide neuroprotection following an ischemic insult—namely MPA was only protective in female-derived tissue. This adds further support to the notion sex is an important factor to consider when investigating future drug targets for CNS disorders, such as ischemic stroke.

Anti-proliferative activities of finasteride in benign prostate epithelial cells require stromal fibroblasts and c-Jun gene

This study aimed to identify the role of mouse fibroblast-mediated c-Jun and IGF-1 signaling in the therapeutic effect of finasteride on benign prostatic epithelial cells. BPH-1 cells, alone or with fibroblasts (c-Jun+/+ or c-Jun-/-), were implanted subcutaneously in male nude mice who were then treated with finasteride. The degrees of cell proliferation, apoptosis, and sizes of the xenografts were determined. BPH-1 cells were grown alone or co-cultured with mouse fibroblasts in the presence of finasteride and the level of IGF-1 secreted into the medium by the fibroblasts was determined. The proliferation-associated signaling pathway in BPH-1 cells was also evaluated. Fibroblasts and c-Jun promoted xenograft growth, stimulated Ki-67 expression, and inhibited BPH-1 apoptosis. Finasteride did not induce the shrinkage of xenografts in the combined-grafted groups despite repressing Ki-67 expression and inducing cell apoptosis. The addition of c-Jun-/- fibroblasts did not promote xenograft growth. In the absence of c-Jun and fibroblasts, finasteride did not alter xenograft growth, Ki-67 expression, or cell apoptosis. The in vitro results demonstrated that when BPH-1 cells were grown in monoculture, treatment with finasteride did not induce cell death and stimulated the expression of pro-proliferative signaling molecules, while in the presence of fibroblasts containing c-Jun, finasteride treatment repressed epithelial cell proliferation, the level of IGF-1 in the medium, and the activation of downstream pro-proliferative signaling pathways. Taken together, our results suggest that fibroblasts, c-Jun, and IGF-1 play key roles in mediating stromal-epithelial interactions that are required for the therapeutic effects of finasteride in benign prostate epithelial cells.

Abstract B18: Interactions between finasteride and vitamin D-related polymorphisms is associated with prostate cancer risk in African American men

Abstract Background: The difference in prostate cancer incidence and survival between European American (EuAm) and African American (AfAm) men is an important health disparity. Vitamin D (VitD) has been linked to key carcinogenesis-related processes and there is strong evidence of cross talk between the androgen and VitD signaling pathways. AfAm men are more likely to be VitD deficient compared to EuAm men which could be one reason for the health disparity. The current study examined genetic variability in the VitD pathway in relation to prostate cancer risk and investigated whether finasteride, a 5α-reductase inhibitor that blocks the metabolism of testosterone, influenced the relationship of cancer risk in EA and AfAm men with VitD-related polymorphisms. Materials and Methods: This nested case-control study included 2,356 men (EuAm: 1,091 cases and 1,088 controls; AfAm: 47 cases, 130 controls) from the Prostate Cancer Prevention Trial, a randomized double-blind, placebo-controlled trial of finasteride for the primary prevention of prostate cancer. In EuAm men, controls were frequency matched to cases on distributions of age, first degree family history of prostate cancer and treatment arm. Due to smaller numbers, all available AfAm men were selected. Participants underwent for-cause or end of study prostate biopies with central pathology review to determine case or control status. Twenty-nine SNPs from 14 genes identified from previous studies as being associated with VitD levels and/or prostate cancer were genotyped from buffy coats using the Illumina VeraCode GoldenGate assay (Illumina Inc; San Diego, CA). Odds ratios were calculated to determine associations of SNP genotypes with prostate cancer risk. Interaction was ermined by adding an interaction term to the logistic models. All statistical tests are 2-sided with p<0.05 considered statistically significant. SAS (ver 9.2, Cary NC) and R (2.15.1, Vienna Austria) were used for all analyses. Results: Three SNPs (C1orf88 rs6599638, CYP24A1 rs6013897, HSD3B1 rs1856888) showed significant interaction by treatment group (finasteride vs. placebo) in AfAm men only (p-interaction for rs6599638, rs6013897, rs1856888 was 0.01, 0.02 and 0.02, respectively). None of the SNPs were associated with cancer in EuAm men and there was no evidence of interaction by treatment group in EuAm men. SNPs rs6599638 and rs6013897 were not associated with cancer in AfAm men in the placebo group. In AfAm men taking finasteride, however, the odds ratios (OR) were significant [rs6599638 AA genotype (7 cases/ 5 controls) compared to AG/GG (12 cases/77 controls) OR= 10.84, 95%CI: 2.77, 45.5; p=0.001; for rs6013897 AA/AT genotypes (13 cases/31 controls) compared to TT (7 cases/51 controls) OR= 3.08, 95%CI: 1.10, 8.60; p=0. 03]. For the rs1856888 SNP, the GG/AG genotypes were protective in the AfAm placebo group [GG/AG (11 cases/33 controls) compared to AA (16 cases/17 controls) OR=0.31, 95%CI: 0.11, 0.84, p= 0.02] but the OR increased to 1.98 in the AfAm finasteride group (p=0.23). The potential impact is limited for rs6599638 as only 10% of AfAm controls have the AA genotype. The impact is larger for rs6013897 and rs1856888 with 41% and 62% of controls with the AA/AT and GG/AG genotypes, respectively. Numbers were too small to examine associations by Gleason grade. Conclusions: There appears to be differential response to finasteride by race and genotype in three of the 29 VitD pathway SNPs examined in the current study. In these three SNPs in the presence of finasteride, the risk genotypes were associated with an increased odds for cancer in AfAm men and not EuAm men. This implies that finasteride may need to be prescribed with caution to some AfAm men. These results should be confirmed in a larger sample size. Citation Format: Kathleen C. Torkko, Cathee Till, Phyllis J. Goodman, Catherine M. Tangen, Adrie van Bokhoven, M. Scott Lucia, Ian M. Thompson, Jr., Ulrike Peters, Marian L. Neuhouser. Interactions between finasteride and vitamin D-related polymorphisms is associated with prostate cancer risk in African American men. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B18.

Opposite effects of dihydrotestosterone and estradiol on apoptosis in the anterior pituitary gland from male rats.

Hormones locally synthesized in the anterior pituitary gland are involved in regulation of pituitary cell renewal. In the pituitary, testosterone (T) may exert its actions per se or by conversion to dihydrotestosterone (DHT) or 17β-estradiol (E2) by 5α-reductase and aromatase activity, which are expressed in this gland. Previous reports from our laboratory showed that estrogens modulate apoptosis of lactotropes and somatotropes from female rats. Now, we examined the in vitro and in vivo effects of gonadal steroids on apoptosis of anterior pituitary cells from adult male rats. T in vitro did not modify apoptosis in anterior pituitary cells from gonadectomized (GNX) male rats. DHT, a non-aromatizable androgen, exerted direct antiapoptotic action on total anterior pituitary cells and folliculo-stellate cells, but not on lactotropes, somatotropes, or gonadotropes. On the contrary, E2 exerted a rapid apoptotic effect on total cells as well as on lactotropes and somatotropes. Incubation of anterior pituitary cells with T in presence of Finasteride, an inhibitor of 5α-reductase, increased the percentage of TUNEL-positive cells. In vivo administration of DHT to GNX rats reduced apoptosis in the anterior pituitary whereas E2 exerted proapoptotic action and reduced cells in G2/M-phase of the cell cycle. In summary, our results indicate that DHT and E2 have opposite effects on apoptosis in the anterior pituitary gland suggesting that local metabolization of T to these steroids could be involved in pituitary cell turnover in males. Changes in expression and/or activity of 5α-reductase and aromatase may play a role in the development of anterior pituitary tumors.

Investigation of the mechanisms of progesterone protection following oxygen–glucose deprivation in organotypic hippocampal slice cultures

This study aimed to test the hypothesis that progesterone is neuroprotective against oxygen–glucose deprivation (OGD) through its conversion to the active metabolite allopregnanolone (AlloP) and the potentiation of GABA A receptors. Organotypic hippocampal cultures were exposed to 2 h of OGD and the resulting cell death was quantified 24 h later using combined propidium iodide and Hoechst immunostaining. Initially, we confirmed, that both progesterone and AlloP were protective in terms of reducing cell death following OGD in hippocampal cultures and for both, the optimal level of protection was observed at a concentration of 0.1 μM. However, the protective effect of progesterone was absent in the presence of finasteride (10 μM) which inhibits the metabolism of progesterone to active metabolites, including AlloP. In addition, the concurrent application of picrotoxin (100 μM), a potent GABA A receptor antagonist, prevented the protection previously seen by either progesterone or AlloP alone. These results indicate that progesterone protects hippocampal cultures from cell death following OGD largely due to its conversion to AlloP and that GABA A receptors are important mediators of the protective effects of both progesterone and AlloP.

Evaluation of MENT on primary cell cultures from benign prostatic hyperplasia and prostate carcinoma

7-alpha-Methyl-19-Nortestosterone (MENT) is a synthetic androgen more potent than testosterone (T) and cannot be reduced at 5-alpha position. No important effects of MENT on prostate growth have been reported. However, little is known about the effect of MENT on benign prostatic hyperplasia (BPH) or prostate carcinoma (CaP). We evaluate the effect of MENT, T and dihydrotestosterone (DHT) on secretion, proliferation and gene expression of primary cell cultures from human BPH and CaP. Moreover, the effect of these androgens was examined in the presence of finasteride to determine the influence of the 5-alpha reductase (5-AR) activity on the androgenic potency. BPH and CaP primary cultures were treated with 0, 1, 10 and 100 nM of T, MENT or DHT during 24 and 48 h. Prostate-specific antigen (PSA) was measured by micro particles immunoassay and proliferation rate by spectrophotometric assay (MTT) and by the immunochemical detection of the proliferation marker Ki-67. Gene expression of FGF8b (androgen sensitive gene) was evaluated by semi-quantitative RT-PCR. Results showed that MENT treatments increased PSA secretion and proliferation rate with a potency ranged between T and DHT. Similar effects of MENT were observed in both BPH and CaP cultures. The studies with finasteride showed that in BPH and CaP cells, the conversion of T into DHT significantly contributes to its effect on the proliferation and PSA secretion, and corroborated the resistance of MENT to the 5-AR. The effect of MENT on the gene expression of FGF8b in CaP cells was similar to T and lower than DHT. It is concluded that MENT increases proliferative and secretory activities and gene expression on pathological prostate cells although in less extent than the active metabolite DHT. Furthermore, the fall of endogenous concentration of T during MENT treatment anticipates that this androgen will be of low impact for the prostate.

Sequential transformation of 4-androstenedione into dihydrotestosterone in prostate carcinoma (DU-145) cells indicates that 4-androstenedione and not testosterone is the substrate of 5α-reductase.

Although it is well recognized that 5α-reductases possess higher affinity for 4-androstenedione than testosterone, and the affinity of 4-androstenedione is higher for 5α-reductases than 17β-hydroxysteroid dehydrogenases, it is generally believed that dihydrotestosterone is necessarily produced by the transformation of testosterone into dihydrotestosterone, suggesting that the step catalyzed by 17β-hydroxysteroid dehydrogenase precedes the step catalyzed by 5α-reductase. This interpretation is in contradiction with the enzymatic kinetic law that suggests that the 5α-reduction step that catalyzes the transformation of 4-dione into 5α-androstane-3,17-dione precedes the 17keto-reduction step. To verify which of these two pathways is operative, we quantified mRNA expression levels of steroidogenic enzymes in prostate carcinoma DU-145 cells by real-time PCR and determined the metabolites produced after incubation with [14C]4-dione in the presence and absence of a 5α-reductase inhibitor and analyzed the metabolites produced by thin layer chromatography and HPLC. Real-time PCR analysis strongly suggests that the new type 3 5α-reductase is responsible for 5α-reductase activity in DU-145 cells. Steroid profile analysis shows that in the absence of inhibitor 5α-androstanedione is first produced, followed by the production of androsterone and dihydrotestosterone. The concentration of testosterone was not detectable. In the presence of Finasteride, an inhibitor of 5α-reductase, there was no transformation of 4-androstenedione and also there was no production of testosterone. The present data clearly indicate that the biosynthesis of dihydrotestosterone in DU-145 cells does not require testosterone as intermediate, and the step catalyzed by 5α-reductase precedes the step catalyzed by 17β-hydroxysteroid dehydrogenase.

Investigation of the anticonvulsive effect of acute immobilization stress in anxious Balb/cByJ mice using GABAA-related mechanistic probes

A disordered regulation of neuroactive steroids release in response to acute stress could induce GABAergic dysfunctions underlying anxiety disorders. First, we conducted studies indicating that a short immobilization stress in anxious Balb/cByJ mice produced an anticonvulsive effect. Second, the effects of different positive allosteric modulators (etifoxine, progesterone, clonazepam, and allopregnanolone) of GABA A receptors were compared in a mouse model mimicking the disruption of the acute stress-induced neuroactive steroids release with finasteride (types I and II 5alpha-reductase inhibitor). The acute stress-induced anticonvulsive effect, expressed by the threshold dose of t-butylbicyclophosphorothionate-producing clonic seizures, was time-dependent. The extent of the enhancement of acute stress-induced anticonvulsive effect was lowered in the presence of finasteride. The same effect was observed with PK11195, which behaves as an antagonist of the peripheral benzodiazepine receptor in the dose range used in this study. Picrotoxin reduced the acute stress anticonvulsive effect, proving that this effect operates through the GABA A receptor. Contrary to progesterone (up to 30 mg/kg), etifoxine (50 mg/kg), allopregnanolone (10 mg/kg), and clonazepam (10 microg/kg) inhibited the finasteride effect in stressed animals. The effect of etifoxine was blocked in the presence of finasteride and picrotoxin combined in stressed animals. These findings support the hypothesis suggesting an involvement of neuroactive steroids in the anticonvulsive effect of restraint stress. The dual and complementary mechanisms of action of etifoxine (directly on the GABA A receptor and indirectly via the neuroactive steroids) may represent a therapeutic benefit in the treatment of various anxiety disorders with abnormal production of neuroactive steroids.

Relative potency of testosterone and dihydrotestosterone in preventing atrophy and apoptosis in the prostate of the castrated rat.

Although dihydrotestosterone (DHT) is the principal androgen in the prostate, testosterone can also act as an androgen in this tissue. To determine the relative potencies of testosterone and DHT in preventing prostate regression, castrated rats were implanted for 4 d with varying doses of testosterone in the presence or absence of the 5alpha-reductase inhibitor finasteride. In the absence of finasteride, testosterone in the prostate is converted to DHT, creating an intraprostatic DHT dose response. In the presence of finasteride, this conversion is blocked, and an intraprostatic testosterone dose response is achieved. DHT was 2.4 times more potent than testosterone at maintaining normal prostate weight and duct lumen mass, a measure of epithelial cell function. The two androgens were equipotent at preventing DNA fragementation and expression of testosterone-repressed prostate message, two measures of apoptosis (cell death). The intraprostatic testosterone concentration that results from finasteride treatment in rats is sufficient to inhibit apoptosis but will not maintain normal epithelial cell activity. In conclusion, whereas DHT is more potent than testosterone at stimulating prostate epithelial cell function as measured by ductal mass, the two androgens are equipotent at preventing prostate cell death after castration. These results explain why finasteride causes prostate involution in the rat with minimal evidence of prostate cell death.