Androgen-independent basal cell re-epithelialization, c-erbB-2 mRNA expression and androgen-dependent EGFr mRNA expression in benign prostatic hyperplasia explant cultures treated with finasteride

EGF promotes the shedding of soluble E-cadherin in an ADAM10-dependent manner in prostate epithelial cells

During the progression of prostate cancer, the epithelial adhesion molecule E-cadherin is cleaved from the cell surface by ADAM15 proteolytic processing, generating an extracellular 80kDa fragment referred to as soluble E-cadherin (sE-cad). Contrary to observations in cancer, the generation of sE-cad appears to correlate with ADAM10 activity in benign prostatic epithelium. The ADAM10-specific inhibitor INCB8765 and the ADAM10 prodomain inhibit the generation of sE-cad, as well as downstream signaling and cell proliferation. Addition of EGF or amphiregulin (AREG) to these untransformed cell lines increases the amount of sE-cad shed into the conditioned media, as well as sE-cad bound to EGFR. EGF-associated shedding appears to be mediated by ADAM10 as shRNA knockdown of ADAM10 results in reduced shedding of sE-cad. To examine the physiologic role of sE-cad on benign prostatic epithelium, we treated BPH-1 and large T immortalized prostate epithelial cells (PrEC) with an sE-cad chimera comprised of the human Fc domain of IgG(1), fused to the extracellular domains of E-cadherin (Fc-Ecad). The treatment of untransformed prostate epithelial cells with Fc-Ecad resulted in phosphorylation of EGFR and downstream signaling through ERK and increased cell proliferation. Pre-treating BPH-1 and PrEC cells with cetuximab, a therapeutic monoclonal antibody against EGFR, decreased the ability of Fc-Ecad to induce EGFR phosphorylation, downstream signaling, and proliferation. These data suggest that ADAM10-generated sE-cad may have a role in EGFR signaling independent of traditional EGFR ligands.

Epidermal growth factor receptor expression escapes androgen regulation in prostate cancer: a potential molecular switch for tumour growth

Androgen deprivation therapy reduces prostate cancer (PCa) tumour growth; however, disease relapse often ensues independently of androgen stimulation, producing androgen-refractory tumours with increased invasion, proliferation, and malignancy. Androgens downregulate epidermal growth factor receptor (EGFR) in normal prostate but not in PCa. Thus, loss of EGFR regulation and altered signalling may, in part, explain the transition of prostate tumours from androgen dependent to androgen independent. Studies in animal models, PCa cell lines, and tumour specimens suggest that androgens modulate prostate growth and function through mechanisms that involve ‘cross-talk’ between androgen receptor (AR) and growth factor receptor signalling pathways. The objective of this review is to discuss the paradoxical relationship between androgen regulation of EGFR in normal prostate and PCa. We reviewed the literature from mid-1980s through 2009 to assess the relationship between androgens and EGFR function in modulating the growth of normal prostate and PCa. Loss of androgen regulation of EGFR in PCa may be responsible for increased tumour growth, invasion, and metastasis, with important implications on the clinical management of PCa. We advance the hypothesis that a molecular switch, responsible for downregulating EGFR expression by androgens in the normal prostate, is either lost or modified in PCa.

Effect of short-term finasteride therapy on peroperative bleeding in patients who were candidates for transurethral resection of the prostate (TUR-P): a randomized controlled study

In the present study we aimed to demonstrate the efficacy of short-term pretreatment with finasteride in patients undergoing transurethral resection of the prostate (TUR-P). For this purpose 40 patients with BPH, who were candidates for TUR-P, were randomized into two groups. The first group (n=20) received 5 mg finasteride/day for 4 weeks prior to surgery and the second group (n=20) remained as the control. Patients who underwent prior prostate or urethral surgery and had a diagnosis of prostate cancer or chronic renal failure, patients who received finasteride, aspirin, coumadin or similar anticoagulant drugs prior to surgery and patients who had capsule perforations or open sinuses during the surgery were excluded from the study. All patients had a normal digital rectal examination and PSA values less than 4 ng/ml. As we look at the results there was no statistically significant difference between the finasteride group and control group regarding age, IPSS, PSA, prostate volumes, preoperative serum hemoglobin, hematocrit values and mean operating times and used irrigating fluids. The total amount of bleeding and bleeding per gram resected tissue were significantly lower in the finasteride group regardless of prostate volume. Furthermore the decrease in the hemoglobin and hematocrit values was higher in the control group. As a conclusion four weeks of finasteride pretreatment provided a significant decrease in peroperative bleeding regardless of prostate volume without any major side effects.

Prevention of Hormone-Related Cancers: Prostate Cancer

Androgens are known to play an important role in normal prostate development, benign prostatic hyperplasia, established prostate cancer, and in prostate carcinogenesis. However, despite convincing experimental and clinical evidence, the epidemiologic data correlating sex steroid levels with disease risk is inconsistent. More recent work has focused on studies of polymorphisms in germ-line DNA in an effort to develop polygenic models of prostate cancer susceptibility and prognosis. Such models have the potential to aid in the selection of men for specific chemopreventive interventions and to help determine which men with localized prostate cancer are most likely to benefit from aggressive therapy. In this review, we will provide a brief summary of androgen metabolic pathways followed by an assessment of the epidemiology literature addressing the relationship between androgens and prostate cancer. Finally, we will address the two major questions that have arisen in response to the recently published results from the Prostate Cancer Prevention Trial: Who are the best candidates for finasteride chemoprevention, and what are the clinical implications of the high prevalence of prostate cancer that was detected in men with prostate-specific antigen levels in the so-called “normal” range?

Transurethral prostate resection and bleeding: a randomized, placebo controlled trial of role of finasteride for decreasing operative blood loss

PURPOSE

Bleeding associated with transurethral prostate resection can often be significant and lead to increased morbidity and occasionally mortality. It has been shown that finasteride decreases bleeding in patients with hematuria of prostatic origin. We hypothesized that bleeding in patients undergoing transurethral prostate resection could be decreased by giving finasteride for 2 weeks before surgery.

MATERIALS AND METHODS

A total 70 patients scheduled to undergo elective transurethral prostate resection were randomized to receive 5 mg. finasteride daily or placebo for 2 weeks before surgery. Serum hemoglobin was measured before and after surgery, and the following day. The volume of irrigation fluid used and its hemoglobin concentration as well as resected prostate weight were recorded.

RESULTS

Of the 68 patients who underwent transurethral prostate resection 2 were withdrawn before surgery, and so 32 received finasteride and 36 received placebo. There was significantly less mean blood loss in irrigation fluid in the finasteride group than in the control group (43.6 versus 69.3 gm. hemoglobin, p = 0.011). The mean difference was more significant when blood loss per gm. resected prostate was calculated (2.65 versus 4.65 gm. hemoglobin per gm. prostate, p < 0.01).

CONCLUSIONS

This study shows that finasteride given for 2 weeks preoperatively decreases bleeding in patients undergoing transurethral prostate resection. Further study is required to determine the optimal timing and dose duration to minimize blood loss and identify how relevant such a decrease in bleeding is in clinical practice.