Abstract 4678: A novel nuclear transporter for androgen receptor and AR-variant-7 in castration resistant prostate cancer: Ideal therapeutic target

Introduction: The dismal outcome of androgen receptor (AR)-targeted therapies in Castration-resistant prostate cancer (CRPC) has been largely attributed to the activation of AR-variants in tumor cells. Although the nuclear carrier of full-length AR (ARFL) is known, the mechanism underlying the nuclear translocation of AR-variants (ARv; which do not have androgen-binding domain) under castration conditions is not completely understood. Understanding such a mechanism could form the basis of future therapies to treat CRPC disease.

Objective: We determined the mechanism involved in the nuclear transport of LBD-devoid AR-variants under CRPC conditions. We for the first time show that “cFLIP” acts a (i) shuttling protein between cytoplasm and nucleus of cells, and (ii) conduit for AR-FL and ARv7 in CRPC cells.

Results: We show that (i) cFLIP-expressing CRPC cells exhibit higher proliferative index than cFLIP-deficient counterparts and (ii) cFLIP expression is high in prostatic tissues of castrated (ARR2.IκBMyc) transgenic mice. The significance of cFLIP as an upstream of AR could be ascertained from the finding that suppressing cFLIP decreased PSA levels and transcriptional activities of AR-FL and ARv7 in CRPC cells. These data prompted to further investigate the correlation between cFLIP, AR-FL and ARv7. We show that cFLIP forms a complex with ARv-7 and AR-FL in CRPC cells. We also show that cFLIP/ARv7 complex levels are high in nuclei than in cytoplasm of CRPC cells suggesting the possibility of cFLIP as a protein carrier. Using transfections with cFLIP-Long, cFLIP-short-variant and mutants (cFLIPL-435mt/472mt/439mt), two sequences on C-terminus of cFLIP were identified for nuclear translocation of AR. These data were also validated in PC3 cells (in which ARv7 was ectopically expressed). We show that β-catenin is required for complex stabilization and AR-nuclear translocation activity of cFLIP. Previously, cFLIP was identified as an androgen-responsive gene. However, we show that cFLIP expression is independent of androgen in CRPC cells

Finally, we established the significance of cFLIP/ARv7 complex as a therapeutic target and showed that simultaneous targeting of ARv and cFLIP (using nanoparticle-loaded cFLIP-siRNA + ARv7-siRNA) significantly inhibited CRPC-type tumor growth and improved the outcome of docetaxel therapy in mouse model. We also identified a novel natural inhibitor of cFLIP/ARv.

Conclusions: We identified novel (i) transporter of AR and (ii) approach for treating CRPC in men.

Citation Format: Aijaz Parray, Hifzur R. Siddique, Alyssa Langfald, Pooja Singh, Mikihiko Naito, Robert Matusik, Ingo Schmitz, Shahriar Koochekpour, Badrinath R. Konety, Mohammad Saleem. A novel nuclear transporter for androgen receptor and AR-variant-7 in castration resistant prostate cancer: Ideal therapeutic target. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4678. doi:10.1158/1538-7445.AM2015-4678

Long-term oncological outcomes of a phase II trial of neoadjuvant chemohormonal therapy followed by radical prostatectomy for patients with clinically localised, high-risk prostate cancer

OBJECTIVE

To determine long-term oncological outcomes of radical prostatectomy (RP) after neoadjuvant chemohormonal therapy (CHT) for clinically localised, high-risk prostate cancer.

PATIENTS AND METHODS

In this phase II multicentre trial of patients with high-risk prostate cancer (PSA level >20 ng/mL, Gleason ≥8, or clinical stage ≥T3), androgen-deprivation therapy (goserelin acetate depot) and paclitaxel, carboplatin and estramustine were administered before RP. We report the long-term oncological outcomes of these patients and compared them to a contemporary cohort who met oncological inclusion criteria but received RP only.

RESULTS

In all, 34 patients were enrolled and followed for a median of 13.1 years. Within 10 years most patients had biochemical recurrence (BCR-free probability 22%; 95% confidence interval [CI] 10-37%). However, the probability of disease-specific survival at 10 years was 84% (95% CI 66-93%) and overall survival was 78% (95% CI 60-89%). The CHT group had higher-risk features than the comparison group (123 patients), with an almost doubled risk of calculated preoperative 5-year BCR (69% vs 36%, P < 0.01). After adjusting for these imbalances the CHT group had trends toward improvement in BCR (hazard ratio [HR] 0.76, 95% CI 0.43-1.34; P = 0.3) and metastasis-free survival (HR 0.55, 95% CI 0.24-1.29; P = 0.2) although these were not statistically significant.

CONCLUSIONS

Neoadjuvant CHT followed by RP was associated with lower rates of BCR and metastasis compared with the RP-only group; however, these results were not statistically significant. Because this treatment strategy has known harms and unproven benefit, this strategy should only be instituted in the setting of a clinical trial.

The RAZOR (randomized open vs robotic cystectomy) trial: study design and trial update

The purpose of the RAZOR (randomized open vs robotic cystectomy) study is to compare open radical cystectomy (ORC) vs robot-assisted RC (RARC), pelvic lymph node dissection (PLND) and urinary diversion for oncological outcomes, complications and health-related quality of life (HRQL) measures with a primary endpoint of 2-year progression-free survival (PFS). RAZOR is a multi-institutional, randomized, non-inferior, phase III trial that will enrol at least 320 patients with T1-T4, N0-N1, M0 bladder cancer with ≈160 patients in both the RARC and ORC arms at 15 participating institutions. Data will be collected prospectively at each institution for cancer outcomes, complications of surgery and HRQL measures, and then submitted to trial data management services Cancer Research and Biostatistics (CRAB) for final analyses. To date, 306 patients have been randomized and accrual to the RAZOR trial is expected to conclude in 2014. In this study, we report the RAZOR trial experimental design, objectives, data safety, and monitoring, and accrual update. The RAZOR trial is a landmark study in urological oncology, randomizing T1-T4, N0-N1, M0 patients with bladder cancer to ORC vs RARC, PLND and urinary diversion. RAZOR is a multi-institutional, non-inferiority trial evaluating cancer outcomes, surgical complications and HRQL measures of ORC vs RARC with a primary endpoint of 2-year PFS. Full data from the RAZOR trial are not expected until 2016-2017.

ROBO1, a tumor suppressor and critical molecular barrier for localized tumor cells to acquire invasive phenotype: study in African-American and Caucasian prostate cancer models

High-risk populations exhibit early transformation of localized prostate cancer (CaP) disease to metastasis which results in the mortality of such patients. The paucity of knowledge about the molecular mechanism involved in acquiring of metastatic behavior by primary tumor cells and non-availability of reliable phenotype-discriminating biomarkers are stumbling blocks in the management of CaP disease. Here, we determine the role and translational relevance of ROBO1 (an organogenesis-associated gene) in human CaP. Employing CaP-progression models and prostatic tissues of Caucasian and African-American patients, we show that ROBO1 expression is localized to cell-membrane and significantly lost in primary and metastatic tumors. While Caucasians exhibited similar ROBO1 levels in primary and metastatic phenotype, a significant difference was observed between tumor phenotypes in African-Americans. Epigenetic assays identified promoter methylation of ROBO1 specific to African-American metastatic CaP cells. Using African-American CaP models for further studies, we show that ROBO1 negatively regulates motility and invasiveness of primary CaP cells, and its loss causes these cells to acquire invasive trait. To understand the underlying mechanism, we employed ROBO1-expressing/ROBO1-C2C3-mutant constructs, immunoprecipitation, confocal-microscopy and luciferase-reporter techniques. We show that ROBO1 through its interaction with DOCK1 (at SH3-SH2-domain) controls the Rac-activation. However, loss of ROBO1 results in Rac1-activation which in turn causes E-Cadherin/β-catenin cytoskeleton destabilization and induction of cell migration. We suggest that ROBO1 is a predictive biomarker that has potential to discriminate among CaP types, and could be exploited as a molecular target to inhibit the progression of disease as well as treat metastasis in high-risk populations such as African-Americans.

Treatment and survival in patients with recurrent high-risk non-muscle-invasive bladder cancer

BACKGROUND

Multiple recurrences develop in patients with high-risk non-muscle-invasive bladder cancer. As neither the association of recurrences with survival nor the subsequent aggressive treatment in individuals with recurrent high-grade non-muscle-invasive bladder cancer has ever been quantified, we sought to determine whether the increasing number of recurrences is associated with higher subsequent treatment and mortality rates.

METHODS

Using linked Surveillance, Epidemiology, and End Results-Medicare data, we identified subjects with recurrent high-grade, non-muscle-invasive disease diagnosed in 1992 to 2002 and followed up until 2007. Using competing-risks regression analyses, we quantified the incidence of radical cystectomy, radiotherapy, and systemic chemotherapy after each recurrence. We then performed a propensity-score adjusted competing-risks regression analysis to determine whether the increasing recurrences portend worse survival.

RESULTS

Of 4,521 subjects, 2,694 (59.6%) had multiple recurrences within 2 years of diagnosis. Compared with patients who only had 1 recurrence, those with ≥ 4 recurrences were less likely to undergo radical cystectomy (hazard ratio [HR] = 0.73, 95% CI: 0.58-0.92), yet more likely to undergo radiotherapy (HR = 1.51, 95% CI: 1.23-1.85) and systemic chemotherapy (HR = 1.58, 95% CI: 1.15-2.18). For patients with ≥ 4 recurrences, only 25% were treated with curative intent. The 10-year cancer-specific mortality rates were 6.9%, 9.7%, 13.7%, and 15.7% for those with 1, 2, 3, and ≥ 4 recurrences, respectively.

CONCLUSIONS

Only 25% of patients with high-risk non-muscle-invasive bladder cancer who experienced recurrences at least 4 times underwent radical cystectomy or radiotherapy. Despite portending worse outcomes, increasing recurrences do not necessarily translate into higher treatment rates.

Risk of end stage kidney disease after radical cystectomy according to urinary diversion type

PURPOSE

The risk of renal insufficiency has historically been viewed as a long-term consequence of urinary diversion after radical cystectomy. However, there are little data on the long-term rate of end stage kidney disease after urinary diversion and few studies have compared end stage kidney disease rates by diversion type. In a large, population based cohort we evaluated the risk of end stage kidney disease in patients who received an ileal conduit vs continent urinary diversion after cystectomy for bladder cancer.

MATERIALS AND METHODS

Using the SEER-Medicare 1992 to 2010 data set we identified 4,015 patients treated with radical cystectomy for bladder cancer, excluding those with preexisting renal disease or clinically significant preoperative hydronephrosis. The outcome of interest was end stage kidney disease stratified by diversion type. We used a Cox proportional hazard model for multivariate analysis controlling for demographic, tumor and comorbidity characteristics.

RESULTS

End stage kidney disease developed in 7.2% of patients, including 84% with an ileal conduit and 16% with continent urinary diversion. Median followup was 34 months (IQR 12-73). On multivariate analysis no increased risk of end stage kidney disease was associated with continent diversion (HR 1.06, 95% CI 0.78-1.44, p = 0.71). Overall the estimated risk at 5, 10 and 15 years was 8.3% (95% CI 7.1-9.5), 16.9% (95% 14.6-19.2) and 24.4% (95% CI 20.3-28.5), respectively.

CONCLUSIONS

No significant difference in the rate of end stage kidney disease was identified when comparing ileal conduits to continent urinary diversion. A significant risk of end stage kidney disease in the long term was identified in patients with post-cystectomy survival beyond 5 years.

Hexaminolevulinate blue-light cystoscopy in non-muscle-invasive bladder cancer: review of the clinical evidence and consensus statement on appropriate use in the USA

Hexaminolevulinate (HAL) is a tumour photosensitizer that is used in combination with blue-light cystoscopy (BLC) as an adjunct to white-light cystoscopy (WLC) in the diagnosis and management of non-muscle-invasive bladder cancer (NMIBC). Since being licensed in Europe in 2005, HAL has been used in >200,000 procedures, with consistent evidence that it improves detection compared with WLC alone. Current data support an additional role in the reduction of recurrence of NMIBC. Since the approval of HAL by the FDA in 2010, experience of HAL-BLC in the USA continues to expand. To define areas of need and to identify the benefits of HAL-BLC in clinical practice, a focus group of expert urologists specializing in the management of patients with bladder cancer convened to review the clinical evidence, share their experiences and reach a consensus regarding the optimal use of HAL-BLC in the USA. The focus group concluded that HAL-BLC should be considered for initial assessment of NMIBC, surveillance for recurrent tumours, diagnosis in patients with positive urine cytology but negative WLC findings, and for tumour staging.

Challenges of managing elderly men with prostate cancer

The incidence of prostate cancer increases with age. Current evidence suggests that prostate cancer is under treated in patients aged ≥70 years, despite evidence of efficacy and acceptable toxicity. Radical cystectomy and definitive radiotherapy are often denied owing to fears of post-operative complications and radiotherapy-associated gastrointestinal and genitourinary toxicity. However, modern radical prostatectomy techniques provide excellent clinical outcomes with low perioperative morbidity. Moreover, volume-restricted intensity-modulated radiation therapy is a significant improvement over previous 2D conformal radiotherapy with similar efficacy and lower toxicity. Androgen-deprivation therapy is also under-prescribed among the elderly, owing to concerns of increases in cardiac deaths and osteoporosis acceleration. However, prospective trials have not identified any increase in cardiovascular mortality among elderly men receiving androgen-deprivation therapy compared to age-matched controls. Most patients on androgen deprivation eventually progress to a castration-resistant state. At this stage, the disease still responds to newer agents that target the androgen pathway and to chemotherapy. Among the elderly, chemotherapy is under-prescribed even though it has been demonstrated to be palliative and improve survival. We describe the trends in prostate cancer management in the elderly and the importance of assessing comorbidity status, tumour characteristics, and health status, including a complete geriatric evaluation, before making treatment recommendations.

Endoscopic gold fiducial marker placement into the bladder wall to optimize radiotherapy targeting for bladder-preserving management of muscle-invasive bladder cancer: feasibility and initial outcomes

Background and Purpose

Bladder radiotherapy is a management option for carefully selected patients with muscle-invasive bladder cancer. However, the inability to visualize the tumor site during treatment and normal bladder movement limits targeting accuracy and increases collateral radiation. A means to accurately and reliably target the bladder during radiotherapy is needed.

Materials and Methods

Eighteen consecutive patients with muscle-invasive bladder cancer (T1–T4) elected bladder-preserving treatment with maximal transurethral resection (TUR), radiation and concurrent chemotherapy. All underwent endoscopic placement of 24-K gold fiducial markers modified with micro-tines (70 [2.9×0.9 mm.]; 19 [2.1×0.7 mm.) into healthy submucosa 5-10 mm. from the resection margin, using custom-made coaxial needles. Marker migration was assessed for with intra-op bladder-filling cystogram and measurement of distance between markers. Set-up error and marker retention through completion of radiotherapy was confirmed by on-table portal imaging.

Results

Between 1/2007 and 7/2012, a total of 89 markers (3–5 per tumor site) were placed into 18 patients of mean age 73.6 years. Two patients elected cystectomy before starting treatment; 16/18 completed chemo-radiotherapy. All (100%) markers were visible with all on-table (portal, cone-beam CT), fluoroscopy, plain-film, and CT-scan imaging. In two patients, 1 of 4 markers placed at the tumor site fell-out (voided) during the second half of radiotherapy. All other markers (80/82, 98%) were present through the end of radio-therapy. No intraoperative (e.g. uncontrolled bleeding, collateral injury) or post-operative complications (e.g. stone formation, urinary tract infection, post-TUR hematuria >48 hours) occurred. Use of micro-tined fiducial tumor-site markers afforded a 2 to 6-fold reduction in bladder-area targeted with high-dose radiation.

Discussion

Placement of the micro-tined fiducial markers into the bladder was feasible and associated with excellent retention-rate and no complications. All markers were well-visualized during radiotherapy with all imaging modalities. Bladder fiducial markers improve targeting accuracy, and may increase treatment efficacy and reduce morbidity from collateral radiation.

Treatment patterns in patients with recurrent high-risk bladder cancer

303

Background: Patients with high-risk bladder cancer are apt to develop multiple recurrences. Since the association of recurrences with aggressive treatment in individuals with recurrent high-grade disease has not been quantified, we sought to determine whether increasing number of recurrences correlates with higher treatment rates. Methods: Using linked SEER-Medicare data, we identified subjects with recurrent high-grade, non-muscle-invasive disease diagnosed in 1992–2002 and followed until 2007. Using propensity score and competing-risks regression analyses, we quantified the incidence of radical cystectomy, radiotherapy, and systemic chemotherapy after each recurrence. We further restricted our analyses of treatment in auspicious environments, defined as those patients most suited for aggressive intervention: age <70, Charlson 0, and undifferentiated T1 tumors treated at academic cancer centers. Results: Of 4,521 subjects, (59.6%) 2,694 recurred more than once within two years of diagnosis. Compared with patients who only had one recurrence, those with ≥4 recurrences were less likely to undergo radical cystectomy (9.7% vs 12.1%, p value=0.03), but more likely to undergo radiotherapy (18.0% vs 12.1%, p value<0.01) and systemic chemotherapy (6.7% vs 4.2%, p value<0.01). For patients with ≥4 recurrences, only 25% were treated with curative intent, while 43% were similarly treated in auspicious environments. Conclusions: Only 25% of patients with high-risk bladder cancer who recur ≥4 times undergo treatment for curative intent. Increasing recurrences do not appear to alter the treatment course, as patients and their doctors may be unable or unwilling to proceed with aggressive treatment despite mounting risk of disease progression. [Table: see text]

Long-term oncologic outcomes of neoadjuvant chemohormonal therapy followed by radical prostatectomy for patients with clinically localized, high-risk prostate cancer

153

Background: To determine long-term oncologic outcomes of radical prostatectomy (RP) after neoadjuvant chemo-hormonal therapy for clinically localized, high-risk prostate cancer. Methods: In this phase II multicenter trial of patients with high-risk prostate cancer (prostate-specific antigen greater than 20ng/ml, Gleason greater than or equal to 8, or clinical stage greater than or equal to T3), androgen deprivation therapy (goserelin acetate depot) and paclitaxel, carboplatin and estramustine were administered prior to RP. We report the long-term oncologic outcomes of these patients and compared them to a contemporary cohort who met oncologic inclusion criteria but received RP only. Results: Thirty four patients were enrolled in this study and followed for a median of 13.1 years. Within 10 years most patients experienced biochemical recurrence (BCR-free probability= 22%; 95% CI 10%, 37%). However the probability of disease-specific survival at 10 years was 84% (95% CI 66%, 93%) and overall survival was 78% (95% CI 60%, 89%). The chemohormonal therapy group had higher-risk features than the comparison group (N=123 patients) with an almost doubled risk of calculated preoperative 5-year BCR (69% vs 36%, p<0.0001). After adjusting for these imbalances the CHT group had trends toward improvement in BCR (0.76, 95% CI 0.43, 1.34; p=0.3) and metastasis free survival (0.55, 95% CI 0.24, 1.29; p=.2) although these were not significant. Conclusions: Neoadjuvant chemohormonal therapy followed by RP was associated with lower observed rates of BCR and metastasis compared to a prostatectomy only group; however these results were not significant. Because this treatment strategy has known harms and unproven benefit, this strategy should only be instituted in the setting of a clinical trial.

The S100A4 Oncoprotein Promotes Prostate Tumorigenesis in a Transgenic Mouse Model: Regulating NFκB through the RAGE Receptor

S100A4, a calcium-binding protein, is known for its role in the metastatic spread of tumor cells, a late event of cancer disease. This is the first report showing that S100A4 is not merely a metastatic protein but also an oncoprotein that plays a critical role in the development of tumors. We earlier showed that S100A4 expression progressively increases in prostatic tissues with the advancement of prostate cancer (CaP) in TRAMP, an autochthonous mouse model. To study the functional significance of S100A4 in CaP, we generated a heterozygously deleted S100A4 (TRAMP/S100A4(+/-)) genotype by crossing TRAMP with S100A4(-/-) mice. TRAMP/S100A4(+/-) did not show a lethal phenotype, and transgenes were functional. As compared to age-matched TRAMP littermates, TRAMP/S100A4(+/-) mice exhibited 1) an increased tumor latency period (P < 0.001), 2) a 0% incidence of metastasis, and 3) reduced prostatic weights (P < 0.001). We generated S100A4-positive clones from S100A4-negative CaP cells and tested their potential. S100A4-positive tumors grew at a faster rate than S100A4-negative tumors in vitro and in a xenograft mouse model. The S100A4 protein exhibited growth factor-like properties in multimode (intracellular and extracellular) forms. We observed that 1) the growth-promoting effect of S100A4 is due to its activation of NFκB, 2) S100A4-deficient tumors exhibit reduced NFκB activity, 3) S100A4 regulates NFκB through the RAGE receptor, and 4) S100A4 and RAGE co-localize in prostatic tissues of mice. Keeping in view its growth-promoting role, we suggest that S100A4 qualifies as an excellent candidate to be exploited for therapeutic agents to treat CaP in humans.

Factors associated with reduction in use of neoadjuvant androgen suppression therapy before radical prostatectomy

OBJECTIVE

To determine whether the prescribing patterns for nonindicated androgen suppression therapy (AST), using neoadjuvant AST as the model, changed according to the prevailing clinical evidence, changes in reimbursement, or evidence of increased harm from treatment.

MATERIALS AND METHODS

We identified 34,976 men with prostate cancer who had undergone radical prostatectomy within 12 months of diagnosis from the Surveillance, Epidemiology, and End Results-Medicare data set (1992-2007), and their clinical and demographic parameters were assessed. We measured the Medicare claims for receipt of AST before radical prostatectomy and calculated the annual rates of neoadjuvant AST, which were adjusted for confounding variables using multivariate logistic regression analysis, and compared them with the prevailing published clinical data on the outcomes of neoadjuvant AST, changes in reimbursement, or published data on clinical harm from treatment.

RESULTS

The use of neoadjuvant AST increased from 7.8% in 1992 to a peak of 17.6% in 1996 and then decreased steadily to 4.6% in 2007. This rate change was significant on multivariate regression analysis, with a single join point in 1996 (P <.001), and corresponded to published data showing improved surgical margin rates and pathologic downstaging in the early 1990s and data showing no improvement in disease recurrence or overall survival beginning in 1997. Changes in reimbursement and evidence of harm from AST were not associated with the decreased use of neoadjuvant AST.

CONCLUSION

Using neoadjuvant AST as the model for the nonindicated use of AST, physicians reduced AST use in response to high-level evidence showing a lack of benefit, despite the high reimbursement. This suggests that physicians adapt to emerging evidence and use evidence-based practice.

Recurrence of high-risk bladder cancer: a population-based analysis

BACKGROUND

Patients with bladder cancer are apt to develop multiple recurrences that require intervention. The recurrence, progression, and bladder cancer-related mortality rates were examined in a cohort of individuals with high-grade non-muscle-invasive bladder cancer.

METHODS

Using linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data, subjects were identified who had a diagnosis of high-grade, non-muscle-invasive disease in 1992 to 2002 and who were followed until 2007. Multivariate competing-risks regression analyses were then used to examine recurrence, progression, and bladder cancer-related mortality rates.

RESULTS

Of 7410 subjects, 2897 (39.1%) experienced a recurrence without progression, 2449 (33.0%) experienced disease progression, of whom 981 succumbed to bladder cancer. Using competing-risks regression analysis, the 10-year recurrence, progression, and bladder cancer-related mortality rates were found to be 74.3%, 33.3%, and 12.3%, respectively. Stage T1 was the only variable associated with a higher rate of recurrence. Women, black race, undifferentiated grade, and stage Tis and T1 were associated with a higher risk of progression and mortality. Advanced age (≥ 70) was associated with a higher risk of bladder cancer-related mortality.

CONCLUSIONS

Nearly three-fourths of patients diagnosed with high-risk bladder cancer will recur, progress, or die within 10 years of their diagnosis. Even though most patients do not die of bladder cancer, the vast majority endures the morbidity of recurrence and progression of their cancer. Increasing efforts should be made to offer patients intravesical therapy with the goal of minimizing the incidence of recurrences. Furthermore, the high recurrence rate seen during the first 2 years of diagnosis warrants an intense surveillance schedule.

BMI1 polycomb group protein acts as a master switch for growth and death of tumor cells: regulates TCF4-transcriptional factor-induced BCL2 signaling

For advanced prostate cancer (CaP), the progression of tumors to the state of chemoresistance and paucity of knowledge about the mechanism of chemoresistance are major stumbling blocks in the management of this disease. Here, we provide compelling evidence that BMI1 polycomb group protein and a stem cell factor plays a crucial role in determining the fate of tumors vis-à-vis chemotherapy. We show that progressive increase in the levels of BMI1 occurs during the progression of CaP disease in humans. We show that BMI1-rich tumor cells are non-responsive to chemotherapy whereas BMI1-silenced tumor cells are responsive to therapy. By employing microarray, ChIP, immunoblot and Luciferase reporter assays, we identified a unique mechanism through which BMI1 rescues tumor cells from chemotherapy. We found that BMI1 regulates (i) activity of TCF4 transcriptional factor and (ii) binding of TCF4 to the promoter region of anti-apoptotic BCL2 gene. Notably, an increased TCF4 occupancy on BCL2 gene was observed in prostatic tissues exhibiting high BMI1 levels. Using tumor cells other than CaP, we also showed that regulation of TCF4-mediated BCL2 by BMI1 is universal. It is noteworthy that forced expression of BMI1 was observed to drive normal cells to hyperproliferative mode. We show that targeting BMI1 improves the outcome of docetaxel therapy in animal models bearing chemoresistant prostatic tumors. We suggest that BMI1 could be exploited as a potential molecular target for therapeutics to treat chemoresistant tumors.

Early detection of prostate cancer: AUA Guideline

PURPOSE

The guideline purpose is to provide the urologist with a framework for the early detection of prostate cancer in asymptomatic average risk men.

MATERIALS AND METHODS

A systematic review was conducted and summarized evidence derived from over 300 studies that addressed the predefined outcomes of interest (prostate cancer incidence/mortality, quality of life, diagnostic accuracy and harms of testing). In addition to the quality of evidence, the panel considered values and preferences expressed in a clinical setting (patient-physician dyad) rather than having a public health perspective. Guideline statements were organized by age group in years (age <40; 40 to 54; 55 to 69; ≥ 70).

RESULTS

Except prostate specific antigen-based prostate cancer screening, there was minimal evidence to assess the outcomes of interest for other tests. The quality of evidence for the benefits of screening was moderate, and evidence for harm was high for men age 55 to 69 years. For men outside this age range, evidence was lacking for benefit, but the harms of screening, including over diagnosis and overtreatment, remained. Modeled data suggested that a screening interval of two years or more may be preferred to reduce the harms of screening.

CONCLUSIONS

The Panel recommended shared decision-making for men age 55 to 69 years considering PSA-based screening, a target age group for whom benefits may outweigh harms. Outside this age range, PSA-based screening as a routine could not be recommended based on the available evidence.

Multi-institutional analysis of sequential intravesical gemcitabine and mitomycin C chemotherapy for non-muscle invasive bladder cancer

OBJECTIVE

Apart from cystectomy, few treatment options exist for the management of bacillus Calmette-Guerin refractory non-muscle invasive bladder cancer (NMIBC). We report a multi-institutional experience with sequential intravesical combination chemotherapy using gemcitabine and mitomycin C (MMC) for NMIBC in the treatment of high-risk patients.

METHODS

We performed a retrospective review of patients who received 6 weekly treatments with sequential intravesical gemcitabine (1g) and MMC (40 mg) chemotherapy for NMIBC. Gemcitabine was administered first and retained for 90 minutes and then drained. MMC was then administered directly after and retained for an additional 90 minutes. Forty-seven patients received treatment from 3 academic tertiary referral centers between 2000 and 2010.

RESULTS

Forty-seven patients (median age 70, range 32-85; 36 males, 11 females) who previously failed a median of 2 intravesical treatments were reviewed. Complete response, 1-year, and 2-year recurrence-free survival rates for all patients were 68%, 48%, and 38%, respectively. Median recurrence-free survival for all patients was 9 months (range 1-80). Fourteen of 47 patients (30%) remained free of recurrence with a median time to follow-up of 26 months (range 6-80 mo). Ten patients required cystectomy.

CONCLUSION

Sequential intravesical combination chemotherapy using gemcitabine and MMC appears to be a useful treatment for patients with high-grade NMIBC as well as those with prior bacillus Calmette-Guerin failure. Further prospective studies are warranted.

BMI1, stem cell factor acting as novel serum-biomarker for Caucasian and African-American prostate cancer

BACKGROUND

Lack of reliable predictive biomarkers is a stumbling block in the management of prostate cancer (CaP). Prostate-specific antigen (PSA) widely used in clinics has several caveats as a CaP biomarker. African-American CaP patients have poor prognosis than Caucasians, and notably the serum-PSA does not perform well in this group. Further, some men with low serum-PSA remain unnoticed for CaP until they develop disease. Thus, there is a need to identify a reliable diagnostic and predictive biomarker of CaP. Here, we show that BMI1 stem-cell protein is secretory and could be explored for biomarker use in CaP patients.

METHODOLOGY/PRINCIPAL FINDINGS

Semi-quantitative analysis of BMI1 was performed in prostatic tissues of TRAMP (autochthonous transgenic mouse model), human CaP patients, and in cell-based models representing normal and different CaP phenotypes in African-American and Caucasian men, by employing immunohistochemistry, immunoblotting and Slot-blotting. Quantitative analysis of BMI1 and PSA were performed in blood and culture-media of siRNA-transfected and non-transfected cells by employing ELISA. BMI1 protein is (i) secreted by CaP cells, (ii) increased in the apical region of epithelial cells and stromal region in prostatic tumors, and (iii) detected in human blood. BMI1 is detectable in blood of CaP patients in an order of increasing tumor stage, exhibit a positive correlation with serum-PSA and importantly is detectable in patients which exhibit low serum-PSA. The clinical significance of BMI1 as a biomarker could be ascertained from observation that CaP cells secrete this protein in higher levels than cells representative of benign prostatic hyperplasia (BPH).

CONCLUSIONS/SIGNIFICANCE

BMI1 could be developed as a dual bio-marker (serum and biopsy) for the diagnosis and prognosis of CaP in Caucasian and African-American men. Though compelling these data warrant further investigation in a cohort of African-American patients.

A cost containment strategy for radical retropubic prostatectomy: Results from implementation of a clinical pathway program

Health care costs from the management of prostate cancer are estimated at $1.5 billion per year. As the number of radical prostatectomies being performed increases, a simultaneous rise in these costs can be expected. However, diminishing resources and the expanding managed care environment necessitate measures to curtail and even reduce these inflationary trends in health care expenditure. With this in mind, we established a collaborative clinical pathway for patients undergoing radical retropubic prostatectomy at our institution. The goals of the pathway were to reduce patient costs and hospital stay and to promote efficient use of resources for the procedure. We studied 71 patients who underwent radical retropubic prostatectomy and were managed according to the pathway during the first year of its implementation (July 1994 through July 1995). Outcome variables for these patients were compared with those of a group of 65 patients who underwent an identical procedure during the previous year (July 1993 through June 1994) before implementation of the pathway. Outcome parameters that were compared included hospital charges, length of stay (LOS), operating room (OR) time, units of packed red cells transfused, morbidity, and mortality. The overall hospital charges since implementation of the pathway decreased by 17.2% when corrected for inflation (p ≤ 0.006). LOS also decreased from a mean of 6.4 days to 5.2 days. There was no significant change in OR time. Overall complications remained unaffected (12.3% vs 12.6%). Based on these results, we conclude that establishment of an individualized, procedure-oriented clinical pathway for patients undergoing radical retropubic prostatectomy can result in significant reduction in patient costs without appreciable effect on morbidity and mortality.

Castration-resistant prostate cancer: potential targets and therapies

The treatment landscape for patients with castration-resistant prostate cancer (CRPC) is undergoing significant changes with the advent of new therapies and multidisciplinary efforts by scientists and clinicians. As activation of multiple molecular pathways in the neoplastic prostate makes it impossible for single-target drugs to be completely effective in treating CRPC, this has led to combination therapy strategy, where several molecules involved in tumor growth and disease progression are targeted by a therapeutic regimen. In the present review, we provide an update on the molecular pathways that play an important role in the pathogenesis of CRPC and discuss the current wave of new treatments to combat this lethal disease.