Effectiveness of convective water vapor energy therapy versus prostatic urethral lift for symptomatic benign prostatic hyperplasia: a systematic review and indirect comparison.

PURPOSE: To synthesize the evidence from randomized controlled trials of prostatic urethral lift (PUL) and convective water vapor thermal energy therapy (WAVE) for minimally invasive treatment of men with benign prostatic hyperplasia. METHODS: A systematic search of databases was performed to identify trials comparing WAVE or PUL to either an active or sham surgery control in subjects with symptomatic benign prostatic obstruction. A controlled indirect treatment comparison based on the approach of Bucher was performed for outcomes including International Prostate Symptom Score and maximum urinary flow rate (Qmax). The durability of treatment response was assessed by life-table analysis of freedom from retreatment through 4 years. RESULTS: Two multicenter sham-controlled trials (Rezum II Study, NCT01912339: LIFT Study, NCT01294150) were identified. The trials employed a common sham procedure and were similar with respect to their designs and subjects' baseline characteristics. Comparisons on the treatment effect in excess of sham response found non-significant differences between WAVE and PUL for symptom score [mean difference (MD): - 1.7 points; 95% confidence interval (CI): - 4.8, 1.4] but Qmax improvements favored WAVE [MD: 3.4 ml/sec; CI: 1.2, 5.6]. The proportion free of retreatment through 4 years was 89.1% for WAVE versus 75.4% for PUL [log-rank P = 0.004]. CONCLUSIONS: PUL and WAVE provide similar subjective improvements but flow-rate improvement and durability of response seem greater for WAVE. The confirmation of these findings in a randomized trial is warranted.

Drug and device development for localized prostate cancer: report of a Food and Drug Administration/American Urological Association public workshop.

Summary of the discussion at a public workshop cosponsored by the U.S. Food and Drug Administration (FDA) and the American Urological Association reviewing potential trial designs for product and device development for the treatment of localized prostate cancer. Product development for treatment of localized prostate cancer has been stymied by the impracticality of using overall survival as an endpoint in patients with localized disease and the lack of acceptable surrogate endpoints. A workshop evaluating potential trial designs for the development of therapies for localized prostate cancer was held in San Diego, CA, in May 2013. Invited experts represented multiple stakeholders, including urology, medical oncology, radiation oncology, industry, and patient advocates. The expert panel discussed development of products for all risk strata of clinically localized prostate cancer. The panel responded to specific questions from FDA, discussing trial design for patients with low-, intermediate-, and high-risk prostate cancer, focal therapy for prostate cancer, patients who have undergone definitive radiation therapy, and adjuvant therapy for patients undergoing radiation therapy or surgery. Expert commentary provided by the panel will inform a planned FDA guidance on pathways for product and device development for treatment of localized prostate cancer and will be discussed at meetings of the FDA's Oncologic Drugs Advisory Committee. FDA intends to develop a set of principles that can be used to promote the development of new products or devices for the treatment of this disease.

Clinical trial design for the development of new therapies for nonmuscle-invasive bladder cancer: report of a Food and Drug Administration and American Urological Association public workshop.

OBJECTIVE: To summarize the discussion at a public workshop, cosponsored by the U.S. Food and Drug Administration (FDA) and the American Urological Association, reviewing potential trial designs for the development of new therapies for non-muscle-invasive bladder cancer (NMIBC). There have been only 3 drug approvals for NMIBC in the last 30 years, and product development for this disease has been stymied by difficulties in trial design and patient accrual. METHODS: A workshop evaluating potential trial design for the development of therapies for NMIBC was held in San Diego, CA, in May 2013. Invited experts representing all stakeholders, including urology, medical oncology, radiation oncology, industry, and patient advocates, discussed development of products for all risk strata of NMIBC. RESULTS: The panel responded to specific questions from the FDA, discussing eligibility criteria, efficacy endpoints, and trial design for patients with a mix of high-grade papillary disease and carcinoma in situ, Bacillus Calmette-Guerin (BCG)-refractory disease, and intermediate-risk disease. Panel members also addressed the magnitude of response that would be clinically meaningful for various disease strata and trial design options for perioperative intravesical chemotherapy instillation at the time of resection of bladder tumors. CONCLUSION: Expert commentary provided by panel members will inform a planned FDA guidance on pathways for drug and biologic development for NMIBC and will be discussed at meetings of the FDA's Oncologic Drugs Advisory Committee. FDA intends to develop a set of principles that can be used to promote the development of new products for this disease.

Toremifene to reduce fracture risk in men receiving androgen deprivation therapy for prostate cancer.

PURPOSE: Androgen deprivation therapy is associated with fracture risk in men with prostate cancer. We assessed the effects of toremifene, a selective estrogen receptor modulator, on fracture incidence in men receiving androgen deprivation therapy during a 2-year period. MATERIALS AND METHODS: In this double-blind, placebo controlled phase III study 646 men receiving androgen deprivation therapy for prostate cancer were assigned to toremifene (80 mg by mouth daily) and 638 were assigned to placebo. Subjects were followed for 2 years. The primary study end point was new vertebral fractures. Secondary end points included fragility fractures, bone mineral density and lipid changes. RESULTS: The 2-year incidence of new vertebral fractures was 4.9% in the placebo group vs 2.5% in the toremifene group, a significant relative risk reduction of 50% (95% CI -1.5 to 75.0, p = 0.05). Toremifene significantly increased bone mineral density at the lumbar spine, hip and femoral neck vs placebo (p <0.0001 for all comparisons). There was a concomitant decrease in markers of bone turnover (p <0.05 for all comparisons). Toremifene also significantly improved lipid profiles. Venous thromboembolic events occurred more frequently with toremifene than placebo with 7 subjects (1.1%) in the placebo group experiencing a venous thromboembolic event vs 17 (2.6%) in the toremifene group. Other adverse events were similar between the groups. CONCLUSIONS: Toremifene significantly decreased the incidence of new vertebral fractures in men receiving androgen deprivation therapy for prostate cancer. It also significantly improved bone mineral density, bone turnover markers and serum lipid profiles.

Preclinical characterization of a novel diphenyl benzamide selective ERα agonist for hormone therapy in prostate cancer.

Androgen deprivation therapy (ADT) is the mainstay of treatment for advanced prostate cancer. ADT improves overall and disease-free survival rates, but long-term therapy is associated with severe side effects of androgen and estrogen depletion including hot flashes, weight gain, depression, and osteoporosis. Effective hormone reduction can be achieved without estrogen deficiency-related side effects by using therapy with estrogenic compounds. However, cardiovascular complications induced by estrogens coupled with the availability of LHRH agonists led to discontinuation of estrogen use for primary androgen deprivation therapy in the 1980s. New treatments for prostate cancer that improve patient outcomes without the serious estrogen deficiency-related toxicities associated with ADT using LHRH analogs are needed. Herein we describe a novel nonsteroidal selective estrogen receptor-α agonist designed for first-line therapy of advanced prostate cancer that in animal models induces medical castration and minimizes many of the estrogen deficiency-related side effects of ADT. The present studies show that orally administered GTx-758 reversibly suppressed testosterone to castrate levels and subsequently reduced prostate volume and circulating prostate-specific antigen in relevant preclinical models without inducing hot flashes, bone loss, thrombophilia, hypercoagulation, or increasing fat mass.

Racial differences in bone mineral density and fractures in men receiving androgen deprivation therapy for prostate cancer.

PURPOSE: Whether race influences bone loss and fracture risk during androgen deprivation therapy for prostate cancer is unknown. Using data from a prospective clinical trial we compared bone mineral density and fracture between African-American and Caucasian men receiving androgen deprivation therapy. MATERIALS AND METHODS: A total of 516 subjects were in the placebo group of a 2-year randomized placebo controlled fracture prevention trial, and were African-American (68) or Caucasian (448). We compared baseline characteristics, changes in bone mineral density and rates of new fractures between races. RESULTS: Compared to Caucasian men, African-American men had higher baseline hip bone mineral density (mean ± SD 0.98 ± 0.15 vs 0.91 ± 0.15 gm/m(2), p = 0.001) and similar spine bone mineral density (1.09 ± 0.22 vs 1.11 ± 0.22, p = 0.51). There was no difference in prevalent vertebral fractures between African-American and Caucasian men (7.4% vs 15.0%, p = 0.13). The percentage change in hip bone mineral density at 2 years was similar between African-American and Caucasian men (mean ± SE -2.21% ± 0.59% vs -2.54% ± 0.26%, p = 0.65). Changes in bone mineral density of the lumbar spine were also similar between African-American and Caucasian men (-1.74% ± 0.69% vs -1.30% ± 0.33%, p = 0.64). No new vertebral fractures were reported in African-American men but 2 fractures were reported in Caucasian men. CONCLUSIONS: In a clinical trial African-American men receiving androgen deprivation therapy for prostate cancer have a greater hip bone mineral density and tended to have fewer prevalent vertebral fractures than Caucasian men. Despite a lower baseline risk of osteoporosis and fracture, African-American men experience a decrease in bone mineral density similar to that of Caucasian men.

The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial.

BACKGROUND: Cachexia, also known as muscle wasting, is a complex metabolic condition characterized by loss of skeletal muscle and a decline in physical function. Muscle wasting is associated with cancer, sarcopenia, chronic obstructive pulmonary disease, end-stage renal disease, and other chronic conditions and results in significant morbidity and mortality. GTx-024 (enobosarm) is a nonsteroidal selective androgen receptor modulator (SARM) that has tissue-selective anabolic effects in muscle and bone, while sparing other androgenic tissue related to hair growth in women and prostate effects in men. GTx-024 has demonstrated promising pharmacologic effects in preclinical studies and favorable safety and pharmacokinetic profiles in phase I investigation. METHODS: A 12-week double-blind, placebo-controlled phase II clinical trial was conducted to evaluate GTx-024 in 120 healthy elderly men (>60 years of age) and postmenopausal women. The primary endpoint was total lean body mass assessed by dual energy X-ray absorptiometry, and secondary endpoints included physical function, body weight, insulin resistance, and safety. RESULTS: GTx-024 treatment resulted in dose-dependent increases in total lean body mass that were statistically significant (P < 0.001, 3 mg vs. placebo) and clinically meaningful. There were also significant improvements in physical function (P = 0.013, 3 mg vs. placebo) and insulin resistance (P = 0.013, 3 mg vs. placebo). The incidence of adverse events was similar between treatment groups. CONCLUSION: GTx-024 showed a dose-dependent improvement in total lean body mass and physical function and was well tolerated. GTx-024 may be useful in the prevention and/or treatment of muscle wasting associated with cancer and other chronic diseases.

Toremifene decreases vertebral fractures in men younger than 80 years receiving androgen deprivation therapy for prostate cancer.

PURPOSE: Androgen deprivation therapy is associated with an increased fracture risk. In a recent phase III trial toremifene significantly decreased vertebral fractures in men on androgen deprivation therapy. Similar to other selective estrogen receptor modulators, toremifene was associated with an increase in venous thromboembolic events with the greatest risk in men 80 years old or older. In this post hoc analysis we evaluated the efficacy and safety of toremifene in men younger than 80 years. MATERIALS AND METHODS: This analysis included 847 men younger than 80 years, of whom 430 received toremifene 80 mg by mouth daily and 417 received placebo for up to 24 months. The primary end point was new vertebral fractures. Secondary end points included fragility fractures, bone mineral density and safety. RESULTS: Compared with placebo, toremifene decreased the relative risk of new vertebral fractures by 79.5% (95% CI 29.8-94.0, p <0.005). The new vertebral fracture incidence was 1.0% for toremifene and 4.8% for placebo (absolute risk reduction 3.8%). Compared with placebo, toremifene significantly decreased the incidence of nontraumatic fracture or greater than 7% bone loss by 24 months (p <0.0001). Toremifene also significantly increased bone mineral density at all measured sites (all comparisons p <0.001). The incidence of venous thromboembolic events was similar in the toremifene and placebo groups (2.1% and 1.0%, respectively, p = 0.26). The rates of other adverse events were also similar between the groups. CONCLUSIONS: Toremifene significantly decreased new vertebral fractures in men younger than 80 years receiving androgen deprivation therapy for prostate cancer. The risk of venous thromboembolic events was lower than in the overall study population, suggesting an improved risk-benefit profile in younger men.

Factors associated with vertebral fractures in men treated with androgen deprivation therapy for prostate cancer.

PURPOSE: Androgen deprivation therapy for prostate cancer causes accelerated loss of bone mineral density and is associated with increased fracture risk. We evaluated risk factors associated with vertebral fractures among men enrolled in a fracture prevention trial. MATERIALS AND METHODS: Analysis included men receiving androgen deprivation therapy for prostate cancer and enrolled in a phase III fracture prevention trial. All men were 70 years old or older or had a low bone mineral density (T-score less than -1.5 for the lumbar spine or total hip). We analyzed demographic and laboratory characteristics of men with and those without vertebral fractures at study entry. RESULTS: Of the 1,244 subjects 162 (13.0%) had a vertebral fracture at baseline. The 2 factors significantly associated with vertebral fractures were white race (p=0.028 compared with nonwhite race) and osteoporosis (p=0.002 for osteoporosis at any site, p=0.053 for osteoporosis at the spine, p=0.002 for osteoporosis at the hip). Lower bone mineral density was also significantly associated with vertebral fractures when analyzed as a continuous variable. Factors not associated with vertebral fractures included age, country of residence, androgen deprivation therapy duration at baseline, androgen deprivation therapy mode, body mass index, testosterone, estradiol, C-telopeptide, bone specific alkaline phosphatase and osteocalcin. Results were similar in analyses limited to men 70 years old or older. CONCLUSIONS: White race and low bone mineral density were significantly associated with vertebral fractures in this study of men treated with androgen deprivation for prostate cancer. These observations should inform the assessment and management of fracture risk among such men.

Toremifene to reduce fracture risk in men receiving androgen deprivation therapy for prostate cancer.

PURPOSE: Androgen deprivation therapy is associated with fracture risk in men with prostate cancer. We assessed the effects of toremifene, a selective estrogen receptor modulator, on fracture incidence in men receiving androgen deprivation therapy during a 2-year period. MATERIALS AND METHODS: In this double-blind, placebo controlled phase III study 646 men receiving androgen deprivation therapy for prostate cancer were assigned to toremifene (80 mg by mouth daily) and 638 were assigned to placebo. Subjects were followed for 2 years. The primary study end point was new vertebral fractures. Secondary end points included fragility fractures, bone mineral density and lipid changes. RESULTS: The 2-year incidence of new vertebral fractures was 4.9% in the placebo group vs 2.5% in the toremifene group, a significant relative risk reduction of 50% (95% CI -1.5 to 75.0, p = 0.05). Toremifene significantly increased bone mineral density at the lumbar spine, hip and femoral neck vs placebo (p <0.0001 for all comparisons). There was a concomitant decrease in markers of bone turnover (p <0.05 for all comparisons). Toremifene also significantly improved lipid profiles. Venous thromboembolic events occurred more frequently with toremifene than placebo with 7 subjects (1.1%) in the placebo group experiencing a venous thromboembolic event vs 17 (2.6%) in the toremifene group. Other adverse events were similar between the groups. CONCLUSIONS: Toremifene significantly decreased the incidence of new vertebral fractures in men receiving androgen deprivation therapy for prostate cancer. It also significantly improved bone mineral density, bone turnover markers and serum lipid profiles.

Prostate specific antigen as a clinical biomarker for prostate cancer: what's the take home message?

Prostate specific antigen (PSA) continues to be challenged as a legitimate clinical biomarker in early detection of prostate cancer due to lack of specificity for malignant transformation. Skepticism surrounding the utility of serum PSA as a clinical marker is not new and many questioned its initial use in widespread prostate cancer screening due to non-specific expression and low predictive value for cancer detection. Despite these initial concerns, serum PSA measurement along with digital rectal examination (DRE) is currently the accepted practice for prostate cancer screening in the United States with hundreds of thousands of men undergoing serum PSA measurement annually. In contrast to its role for early detection, serum PSA measurement as a surrogate for prostate cancer recurrence (biochemical failure) following curative intent therapy has consummate clinical utility in post-treatment surveillance. As thousands of men each year are aggressively treated for potentially curable prostate cancer, development of simple and effective diagnostic tools for detecting treatment failures should be an important area of biomedical and clinical investigation. We have constructed and tested a home-based prostate cancer surveillance device for use by patients to detect PSA from blood obtained by finger stick. Our initial results suggest that home based PSA testing is feasible and may have clinical utility in management of men treated for prostate cancer.

Restoration of bone morphogenetic protein receptor type II expression leads to a decreased rate of tumor growth in bladder transitional cell carcinoma cell line TSU-Pr1.

Bone morphogenetic proteins (BMPs), potential regulators of cellular growth and metastasis that signal through an interaction with plasma membrane receptors, have been suggested to be important regulators of malignant cells. The present study was carried out to evaluate the potential role of BMP receptor (BMP-R) types IA, IB, and II in bladder transitional cell carcinoma (TCC) cells. Initially, we investigated the expression of these BMP-Rs in 30 archival tissues of human bladder TCC using immunohistochemistry; 10 benign bladder specimens were used for comparison. The results demonstrated that the expression of BMP-Rs is localized preferentially to the transitional epithelium and that there was a significant association between loss of BMP-RII expression and tumor grade. To find a cell line that can serve as a model system for clinical observation, we subsequently examined sensitivity to BMP-4 and expression of BMP-RII, BMP-RIA, and BMP-RIB in three human bladder cancer cell lines, TCC-Sup, RT4, and TSU-Pr1. Of the three cell lines, TSU-Pr1 exhibited a decreased level of BMP-RII expression and was resistant to the growth-inhibitory effect of BMP-4. Overexpression of BMP-RII in TSU-Pr1 cells not only restored BMP-4 responsiveness but also significantly decreased tumorigenicity in vivo. Taken together, these results demonstrate that human bladder TCC tissues have a frequent loss of BMP-RII expression and that overexpression of BMP-RII leads to restoration of BMP signaling and decreased tumor growth in the human bladder TCC cell line TSU-Pr1.

Loss of expression of bone morphogenetic protein receptor type II in human prostate cancer cells.

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta superfamily and signal through a number of membrane receptors. We have previously demonstrated that the loss of expression of BMP receptors (BMPRs) type IA, -IB, and -II (BMP-RIA, -RIB, and -RII) correlates with Gleason score in prostate cancer patients. To evaluate the prognostic value of this observation, we used immunohistochemistry to investigate the expression of BMPRs in association with disease progression in 60 patients. The results demonstrated a significant association between the loss of expression of the three BMPRs and Gleason score and clinical stage. However, only the loss of expression of BMP-RII showed a statistically significant association with 5-year survival rate (P<0.05) and biochemical recurrence-free rate following radical prostatectomy (P<0.005). To elucidate the effect of an abnormal BMP signaling in prostate cancer cells, we transfected dominant-negative BMP-RII (BMP-RIIDN) into the human prostate cancer cell line, PC3M. When a stable clone overexpressing BMP-RIIDN was inoculated subcutaneously into nude mice, the tumor growth rate was approximately 10 times that of control and parental cell line. These observations, taken together, indicate that the loss of BMP-RII expression as measured by immunohistochemistry may be a prognostic marker in prostate cancer patients, and that the loss of BMP-RII function may result in increased tumorigenicity in human prostate cancer cells.

Variation in prostate specific antigen results from 2 different assay platforms: clinical impact on 2304 patients undergoing prostate cancer screening.

PURPOSE: Urologists must contend with fluctuating prostate specific antigen (PSA) results from different assay platforms when deciding whether prostate biopsy is indicated. The contribution of cross-platform variation to these fluctuations is not well understood. To address this question we performed a cross-sectional study comparing 2 popular PSA assays during prostate cancer screening. MATERIALS AND METHODS: The Baylor College of Medicine Prostate Cancer Screening Program is a community outreach program providing free screening to Houston residents. From September 18th to 23, 2000, 2,304 patients underwent digital rectal examination and parallel serum PSA assay by the Hybritech Access (Beckman Coulter, Inc., Chaska, Minnesota) and Centaur (Bayer Diagnostics, Tarrytown, New York) systems. The Wilcoxon signed ranks test was used to compare results. RESULTS: Median PSA was low for the 2 assays (Centaur 0.99 ng/ml and Access 1.09 ng/ml) and Access results were significantly higher (1.23 times) than those obtained with Centaur (p <0.001). Frozen serum from 50 patients with PSA greater than 2.5 were then re-assayed using a third methodology (third Generation Immulite, Diagnostic Products Corp., Los Angeles, California). These data were consistent with Centaur results and significantly lower than Access results (p <0.001). Using a cutoff of PSA greater than 4.0 ng/ml 55 of the 288 patients (19%) with PSA greater than 2.5 ng/ml on the 2 platforms would have been candidates for prostate biopsy based on Access but not on Centaur data. CONCLUSIONS: In a large screening population the Access system measured consistently higher PSA than the Centaur system. These findings provide a basis for interpreting PSA results obtained from 2 commonly used clinical assays.

Decreased expression of bone morphogenetic protein (BMP) receptor type II correlates with insensitivity to BMP-6 in human renal cell carcinoma cells.

PURPOSE: Bone morphogenetic proteins (BMPs) are members of a family of pleiotropic growth factors that play a critical role during renal development as well as maintaining kidney homeostasis. In the present study, we investigated the potential role of BMP receptors (BMPRs) in renal cell carcinoma (RCC) cells. EXPERIMENTAL DESIGN: Immunohistochemistry was used to investigate the expression of BMPRs in human RCC tissues. As an in vitro model of RCC, three cell lines were used: 112, 117, and 181. Northern blot, immunoblot, and reverse transcription-PCR were used to study the expression of BMPRs in the cell lines. Finally, cells were transfected using LipofectAMINE. RESULTS: Normal human kidney tissues express the three BMPRs: types RIA, RIB, and RII. In contrast, human RCC cells frequently exhibit a loss of expression of BMP-RII. In tissue culture, BMP-6 inhibits in a dose-dependent manner the proliferation of 112 cells but not of 117 and 181 cells. Assays for BMPRs demonstrated that 117 and 181 cells express low levels of BMP-RII RNA. When these two BMP-6 resistant cell lines were infected with the adenovirus containing the constitutively active form of BMP-RIA or -RIB in combination with a BMP-6-responsive luciferase reporter construct, luciferase activity increased. Finally, when these cell lines were transfected with BMP-RII, BMP-6-sensitivity was restored. CONCLUSIONS: These results demonstrate that human RCC tissues frequently have decreased levels of expression of BMP-RII and that the human RCC cell lines 117 and 181 are resistant to the growth-inhibitory effect of BMP-6 because they have decreased levels of expression of BMP-RII.

Raloxifene, a mixed estrogen agonist/antagonist, induces apoptosis in androgen-independent human prostate cancer cell lines.

Raloxifene, a selective estrogen receptor (ER) modulator, is a mixed estrogen agonist/antagonist that has been shown to prevent osteoporosis and breast cancer in women. Because the prostate contains high levels of ER-beta, the present study investigated the effect of raloxifene in three well-characterized, androgen-independent human prostate cancer cell lines: (a) PC3; (b) PC3M; and (c) DU145. Reverse transcriptase-PCR and Western blot analysis for ER-alpha and ER-beta demonstrated that all three cell lines express ER-beta, whereas only PC3 and PC3M cells were positive for ER-alpha. After the treatment with raloxifene, a dramatic increase in cell death was observed in a dose-dependent manner in the three prostate cancer cell lines (10(-9) to 10(-6) M range). Because the three prostate cancer cell lines demonstrated similar morphological changes after the raloxifene treatment, PC3 (ER-alpha/ER-beta+) and DU145 (ER-beta+ only) cells were selected to further characterize the raloxifene-induced cell death. Using the nucleus-specific stain 4',6-diamidino-2-phenylindole, nuclear fragmentation was observed in a time-dependent manner in both cell lines after exposure to 10(-6) M raloxifene. Using the terminal deoxynucleotidyl transferase-mediated nick end labeling apoptotic assay, it was demonstrated that the nuclear fragmentation was caused by apoptosis. To investigate the possibility that caspase activation is involved in raloxifene-induced apoptosis, cells were treated with the pan-caspase inhibitor ZVAD. The results demonstrated that the dramatic change in cellular morphology after treatment with raloxifene was no longer observed when cells were pretreated with ZVAD. Immunoblot demonstrated activation of caspases 8 and 9 in PC3 and DU145 cells, respectively. Taken together, these results demonstrate that the mixed estrogen agonist/antagonist, raloxifene, induces apoptosis in androgen-independent human prostate cancer cell lines.

Raloxifene, a selective estrogen receptor modulator, induces apoptosis in androgen-responsive human prostate cancer cell line LNCaP through an androgen-independent pathway.

Raloxifene, a selective estrogen receptor (ER) modulator, is a mixed estrogen agonist/antagonist that has been shown to prevent osteoporosis and breast cancer in women. Because the prostate contains a high level of ER-beta, the present study investigated the effect of raloxifene in the androgen-sensitive human prostate cancer cell line LNCaP. Previously, it has been demonstrated that LNCaP cells express ER-beta but not ER-alpha and that tamoxifene induces apoptosis in these cells. After treatment with raloxifene, a dramatic increase in cell death occurred in a dose-dependent manner (10(-9) to 10(-6) M range). Using the terminal deoxynucleotidyl transferase-mediated nick end labeling apoptotic assay, we demonstrated that the nuclear fragmentation was due to apoptosis. The dramatic change in cellular morphology after treatment with raloxifene was no longer observed when cells were pretreated with a pan-caspase inhibitor, Z-VAD-FMK, and a specific caspase-9 inhibitor, Z-LEHD-FMK. Furthermore, immunoblot demonstrated an activation of caspase-9 in LNCaP cells. Because LNCaP cells contain a mutated androgen receptor that allows cellular proliferation in the presence of antiandrogens, prostate-specific antigen assay and transfection with a reporter construct containing luciferase gene under the control of androgen response element (pARE) were carried out. The results demonstrated that raloxifene does not significantly alter androgen receptor activity in LNCaP cells. Taken together, these results demonstrate that raloxifene, a selective ER modulator, induces apoptosis in the androgen-sensitive human prostate cancer cell line LNCaP through an androgen-independent pathway.