Extramural venous invasion: a novel magnetic resonance imaging biomarker for adverse pathology in bladder cancer.

Extramural venous invasion (EMVI) recognized on magnetic resonance imaging (MRI) is an unequivocal biomarker for detecting adverse outcomes in rectal cancer: however it has not yet been explored in the area of bladder cancer. In this study, we assessed the feasibility of identifying EMVI findings on MRI in patients with bladder cancer and its avail in identifying adverse pathology. In this single-institution retrospective study, the MRI findings inclusive of EMVI was described in patients with bladder cancer that had available imaging between January 2018 and June 2020. Patient demographic and clinical information were retrieved from our electronic medical records system. Histopathologic features frequently associated with poor outcomes including lymphovascular invasion (LVI), variant histology, muscle invasive bladder cancer (MIBC), and extravesical disease (EV) were compared to MRI-EMVI. A total of 38 patients were enrolled in the study, with a median age of 73 years (range 50-101), 76% were male and 23% were females. EMVI was identified in 23 (62%) patients. There was a significant association between EMVI and MIBC (OR = 5.30, CI = 1.11-25.36; P = 0.036), and extravesical disease (OR = 17.77, CI = 2.37-133; P = 0.005). We found a higher probability of presence of LVI and histologic variant in patients with EMVI. EMVI had a sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of 90%, 73%, 94% and 63% respectively in detecting extravesical disease. Our study suggests, EMVI may be a useful biomarker in bladder cancer imaging, is associated with adverse pathology, and could be potentially integrated in the standard of care with regards to MRI reporting systems. A larger study sample size is further warranted to assess feasibility and applicability.

Natural history, and impact of surgery and radiation on survival outcomes of men diagnosed with low-grade prostate cancer at ≤ 55 years of age: a 25-year follow-up of > 60,000 men.

PURPOSE: Low-grade prostate cancer has low mortality rates at 10 years; however, it is unclear if the response is sustained for up to 25 years of follow-up. METHODS: Using Surveillance, Epidemiology, and End Results database, the overall and cancer-specific mortality rates were compared among men ≤ 55 years of age diagnosed with low-grade prostate cancer that either had radical prostatectomy, radiotherapy, or no known treatment. RESULTS: Of the 62,772 men diagnosed with low-grade prostate cancer between 1975 and 2016, about 60%, 20% and 20% of men underwent radical prostatectomy, radiotherapy, and no known treatment, respectively. At a median follow-up of 10 years, almost 2% and 7% of men died of prostate cancer and other causes, respectively. The overall mortality was significantly better in radical prostatectomy group compared to no known treatment group (HR 1.99, CI 1.84-2.15, P value < 0.001), but not between the radiotherapy and no known treatment groups. Moreover, the overall and cancer-specific mortality rates in the radiotherapy group were almost two and three times compared to the radical prostatectomy group, respectively (HR 2.15, CI 2.01-2.29, P value < 0.001 for overall mortality and HR 2.87, CI 2.5-3.29, P value < 0.001 for cancer-specific mortality). CONCLUSIONS: The study confirms low mortality rates in men diagnosed with low-grade prostate cancer for over 25 years' follow-up. While radical prostatectomy improves survival significantly compared to no known treatment, radiotherapy is associated with an increase in overall and cancer-specific mortality, which may be related to long-term toxicities.

Combination therapy in metastatic castration sensitive prostate cancer: A Systematic review and network meta-analysis.

Introduction: Studies directly comparing the different combination therapies offered to men with metastatic castration sensitive prostate cancer (mCSPC), are not available yet. This study was designed using the network meta-analysis (NMA) framework to provide a comparison of the different available options for the treatment of men with mCSPC. Methods: A systematic search was performed and the prospective randomized controlled trials reporting the overall survival (OS) or failure-free survival (FFS) were selected for review. A total of 14 studies were included in the NMA. Results: The addition of abiraterone, apalutamide, docetaxel, and docetaxel with zoledronic acid to the androgen deprivation therapy (ADT) demonstrated a significant improvement in the OS. In indirect comparison, abiraterone had a higher impact on the OS as compared to docetaxel (hazard ratio [HR]: 1.21, 95% confidence interval [CI]: 1.0-1.46) and docetaxel with zoledronic acid (HR: 1.31, 95% CI: 1.05-1.63) but not apalutamide. Furthermore, apalutamide was not different than docetaxel or docetaxel with zoledronic acid. There was a significant improvement in the FFS with the combination of abiraterone, apalutamide, docetaxel (HR: 0.61, 95% CI: 0.46-0.81), docetaxel with zoledronic acid (HR: 0.62, 95% CI: 0.43-0.9), and enzalutamide (HR: 0.39, 95% CI: 0.25-0.61) as compared to the ADT alone. Similar to the indirect comparison of OS, abiraterone outperformed docetaxel (HR: 1.66, 95% CI: 1.12-2.47), docetaxel with zoledronic acid (HR: 1.69, 95% CI: 1.06-2.68), and enzalutamide (HR: 1.06, 95% CI: 0.63-1.80), but not apalutamide in terms of impact on the FFS. Conclusion: Overall, abiraterone demonstrated better OS and FFS outcomes as compared to all the other combination strategies in this NMA.

Pathology grade influences competing mortality risks in elderly men with prostate cancer.

BACKGROUND: Recent guidelines recommend active management of prostate cancer (CaP), especially high-risk disease, in elderly men. However, descriptive data from a large cohort with extended follow up on the risk of death from CaP in men diagnosed over 70 years of age and its relationship to Gleason score (GS) and serum prostate specific antigen (PSA) level is lacking. Using the Surveillance, Epidemiology, and End Results database, we evaluated the influence of GS and serum PSA levels on the risks of mortality from PC (PCM) and mortality from other causes in localized (LPC) and metastatic (MPC) disease in elderly population. METHODS: Men diagnosed with PC over 70 years of age between 2004 and 2016 were divided into LPC and MPC groups, categorized by age: 70-74, 75-79, 80-84, 85-89, and ≥90 years and stratified by GS <7, 7, and >7, and serum PSA level <4, 4-10, 10-20, 20-50, and >50 ng/mL. Competing risk estimates for PCM and mortality from other causes were generated for both groups. RESULTS: Of the 85,649 men, 85.5 % were LPC at diagnosis. Overall, at a median follow up of 4 years, 15% of the men had died including a third from PC. While <15% of men with GS ≤7 died from PC, the PCM was >30% in men with GS >7 in LPC group, which accounted for almost half of total deaths for age 70-84 years. The GS >7 was also significantly associated with PCM in men with MPC. Furthermore, PCM directly correlated with serum PSA levels, with mortality rates reaching up to 50% and 70% for PSA >50 ng/dl for LPC and MPC, respectively. CONCLUSIONS: There is a substantial risk of dying in men diagnosed with LPC over 70 years of age with GS >7 or a serum PSA >20 ng/mL. Furthermore, the risk for death for MPC directly correlated with GS with PCM increasing from 10%-30% for GS ≤7 to >50% for GS >7. The data, in conjunction with other clinical parameters such as comorbidities could be used to counsel elderly men on management options of PC for both localized and metastatic PC.

An Indirect Comparison of Newer Minimally Invasive Treatments for Benign Prostatic Hyperplasia: A Network Meta-Analysis Model.

Objective: This study was designed to provide an indirect comparison of the urinary and sexual domain outcomes and complications after newer minimally invasive surgical therapy (MIST) of Aquablation, Rezum, and UroLift for benign prostatic hyperplasia (BPH) for transurethral resection of prostate (TURP). Methods: We searched Embase, Medline, and Cochrane in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, in December 2019. Only randomized clinical trials (RCTs) that reported outcomes after treatment of BPH for prostate less than 80 g with Aquablation, Rezum, or UroLift were included in the analysis. Results: A total of four RCTs reporting the outcomes after treatment with newer MIST for BPH were identified. Patients undergoing the resective procedures, that is, TURP and Aquablation, had greater improvement in urinary domain outcomes: International Prostate Symptom Score, quality of life, peak flow rate, and postvoiding residual compared to patients undergoing nonresective procedures: UroLift and Rezum. Patients in UroLift group maintained a higher sexual function domain score compared to TURP, but not Aquablation. Our multiple comparison analysis did not reveal a significant difference in urinary and sexual domain scores between patients undergoing UroLift and Rezum at 24 months of follow-up. Conclusions: Aquablation and TURP necessitate general or regional anesthesia and both produced significantly better urinary domain scores compared to Rezum and UroLift. On the other hand, UroLift demonstrated better sexual function domain scores compared to TURP, but not Aquablation. There was no significant difference in urinary domain scores between UroLift and Rezum at 24 months of follow-up.

Intracorporeal versus extracorporeal urinary diversion following robot-assisted radical cystectomy: a meta-analysis, cumulative analysis, and systematic review.

Over the last decade, the increased utilization of robot-assisted radical cystectomy (RARC) in the surgical treatment of muscle-invasive bladder cancer has led to an uptrend in intracorporeal urinary diversions (ICUD). However, the operative results comparing ICUD to extracorporeal urinary diversion (ECUD) have varied widely. We performed a meta-analysis to analyze perioperative outcomes and complications of ICUD compared to ECUD following RARC. This study is registered at International Prospective Register of Systematic Reviews (PROSPERO) CRD42020164074. A systematic literature review was conducted using PubMed, EMBASE, and Cochrane databases in August 2019. A total of six studies comparing ICUD vs ECUD were identified and meta-analysis was conducted on these studies. In addition, a cumulative analysis was also performed on 83 studies that reported perioperative outcomes after RARC and ICUD or ECUD. The Weighed Mean Difference of operative time and blood loss between ICUD and ECUD group was (16; 95% confidence interval - 34 to 66) and (- 86; 95% confidence interval - 124 to - 48), respectively. ICUD and ECUD had comparable early (30-day) and mid-term (30-90-day) complication rate (RR 1.19; 95% confidence interval 0.71-2.0; p = 0.5) and (RR 0.91; 95% confidence interval 0.71-1.15 p = 0.4) respectively. In the 83 studies that were included in the cumulative analysis, the mean operative time for ileal conduit and neobladders by ICUD were 307 and 428 min, respectively, compared to ECUD 428 and 426 min, respectively. ICUD and ECUD have comparable short- and mid-term complication rate. The ICUD group has lower blood loss and lower rate of blood transfusion compared to ECUD.

Comparative efficacy of apalutamide darolutamide and enzalutamide for treatment of non-metastatic castrate-resistant prostate cancer: A systematic review and network meta-analysis.

INTRODUCTION: Studies using apalutamide, enzalutamide, or darolutamide have shown improved metastasis free survival (MFS) rates, leaving clinicians with a dilemma of choosing one over the other, for nonmetastatic castration recurrent prostate cancer (nmCRPC). We performed a network meta-analysis to provide an indirect comparison of oncologic outcomes and adverse events (AEs) of these medications. MATERIAL AND METHODS: We searched PubMed, MEDLINE, and SCOPUS databases, for studies reporting apalutamide, enzalutamide, or darolutamide until January 25, 2020. Results were input into an EndNote library, and data were extracted into a predefined template. Progression free survival (PFS) was defined as radiologic progression or death. Network meta-analysis was done using R and meta-analysis was performed with RevMan v. 5. Surface under the cumulative ranking (SUCRA) value was used to provide rank probabilities. RESULTS: We found 3 studies reporting results for apalutamide, enzalutamide, and darolutamide. MFS was significantly lower in patients receiving darolutamide compared to both apalutamide (hazard ratio [HR]: 0.73, 95% confidence interval [CI]: 0.55-0.97) and enzalutamide (HR: 0.71, 95% CI: 0.54-0.93). MFS was similar for enzalutamide and apalutamide (HR: 0.97, 95% CI: 0.73-1.28). In PFS, apalutamide showed a slightly higher rate compared to darolutamide (HR: 0.76, 95% CI: 0.59-0.99). There was no difference in overall survival (OS) between any of the medications. There was no statistically significant difference in AEs profile of the 3 medications. However, darolutamide had the highest SUCRA value and probability of being the most preferred medication based on AEs profile. CONCLUSION: Enzalutamide and apalutamide had similar and higher MFS rate in indirect comparison with darolutamide. In cases where AEs are concerning, darolutamide might be the preferred agent.

A Systematic Review and Meta-Analysis of Methods Used to Reduce Infectious Complications Following Transrectal Prostate Biopsy.

We reviewed and analyzed the most effective methods to reduce infectious complications (IC) after transrectal prostate biopsy (TRPB). We included only prospective randomized-controlled trials in the analysis. The analysis neither demonstrated any superiority of fluoroquinolones over other antibiotic classes nor of targeted antibiotics over empiric regimens in men undergoing TRPB. However, longer course antibiotics (3 days or more) compared to single dose or day regimens, combination of fluoroquinolones with aminoglycosides compared to fluoroquinolones alone and povidone-iodine rectal cleansing compared to control significantly reduced IC following TRPB. A combination of addition of aminoglycosides to oral antibiotics for 3 days along with povidone-iodine rectal cleansing may be an optimum strategy to minimize the risk of IC after TRPB.

Combination Therapy for Metastatic Renal Cell Carcinoma: A Systematic Review and Network Meta-analysis.

INTRODUCTION: Randomized clinical trials have shown combination therapy to be superior in progression-free survival (PFS) rates when compared with sunitinib alone. However, there have been no direct comparisons among the combination strategies making it unclear as to which may be the preferred option. We performed a network meta-analysis of the combination therapy (immune checkpoint inhibitor plus axitinib or bevacizumab) used in metastatic renal cell carcinoma (mRCC) and provided a rank order preference based on PFS, and adverse events (AEs). MATERIALS AND METHODS: A systematic search on the treatment of mRCC using combination therapy till July 2019 was done. Studies reporting on combination therapies with immune checkpoint inhibitor plus axitinib or bevacizumab for mRCC were selected. Frequentist method was used for rank order generation. RESULTS: A total of 3 studies consisting of 2672 patients were selected. All combination therapies demonstrated improved PFS when compared with sunitinib alone. The rank order for PFS showed combination of pembrolizumab plus axitinib had the highest probability of favorability followed by avelumab plus axitinib and atezolizumab plus bevacizumab (surface under the cumulative ranking 0.9, 0.7, and 0.4, respectively). For AEs, pembrolizumab plus axitinib had the least AEs ≥grade 3, followed by avelumab plus axitinib and atezolizumab plus bevacizumab (surface under the cumulative ranking 0, 0.5, 1.0). CONCLUSIONS: This network meta-analysis demonstrates that combination of pembrolizumab plus axitinib may be the preferred option based on efficacy and side effect profile compared with avelumab plus axitinib or atezolizumab plus bevacizumab. However, all the 3 combination strategies were superior to sunitinib alone in improving PFS in patients with mRCC.

Predictive and targeting value of IGFBP-3 in therapeutically resistant prostate cancer.

BACKGROUND: Our previous studies demonstrated that a novel quinazoline derivative, DZ-50, inhibited prostate cancer epithelial cell invasion and survival by targeting insulin-like-growth factor binding protein-3 (IGFBP-3) and mediating epithelial-mesenchymal transition (EMT) conversion to mesenchymal-epithelial transition (MET). This study investigated the therapeutic value of DZ-50 agent in in vitro and in vivo models of advanced prostate cancer and the ability of the compound to overcome resistance to antiandrogen (enzalutamide) in prostate tumors. APPROACH: LNCaP and LNCaP-enzalutamide resistant human prostate cancer (LNCaP-ER) cells, as well as 22Rv1 and enzalutamide resistant, 22Rv1-ER were used as cell models. The effects of DZ-50 and the antiandrogen, enzalutamide (as single agents or in combination) on cell death, EMT-MET interconversion, and expression of IGFBP3 and the androgen receptor (AR), were examined. The TRAMP mouse model of prostate cancer progression was used as a pre-clinical model. Transgenic mice (20-wks of age) were treated with DZ-50 (100 mg/kg for 2 wks, oral gavage daily) and prostate tumors were subjected to immunohistochemical assessment of apoptosis, cell proliferation, markers of EMT and differentiation and IGFBP-3 and AR expression. A tissue microarray (TMA) was analyzed for expression of IGBP-3, the target of DZ-50 and its association with tumor progression and biochemical recurrence. RESULTS: We found that treatment with DZ-50 enhanced the anti-tumor response to the antiandrogen via promoting EMT to MET interconversion, in vitro. This DZ-50-mediated phenotypic reversal to MET leads to prostate tumor re-differentiation in vivo, by targeting nuclear IGFBP-3 expression (without affecting AR). Analysis of human prostate cancer specimens and TCGA patient cohorts revealed that overexpression of IGBP-3 protein correlated with tumor recurrence and poor patient survival. CONCLUSIONS: These findings provide significant new insights into (a) the predictive value of IGFBP-3 in prostate cancer progression and (b) the antitumor action of DZ-50, [in combination or sequencing with enzalutamide] as a novel approach for the treatment of therapeutically resistant prostate cancer.

Characterization of Novel Murine and Human PDAC Cell Models: Identifying the Role of Intestine Specific Homeobox Gene ISX in Hypoxia and Disease Progression.

Therapy failure and metastasis-associated mortality are stumbling blocks in the management of PDAC in patients. Failure of therapy is associated to intense hypoxic conditions of tumors. To develop effective therapies, a complete understanding of hypoxia-associated changes in genetic landscape of tumors during disease progression is needed. Because artificially immortalized cell lines do not rightly represent the disease progression, studying genetics of tumors in spontaneous models is warranted. In the current study, we generated a spectrum of spontaneous human (UM-PDC1; UM-PDC2) and murine (HI-PanL, HI-PancI, HI-PanM) models representing localized, invasive, and metastatic PDAC from a patient and transgenic mice (K-rasG12D/Pdxcre/Ink4a/p16-/). These spontaneous models grow vigorously under hypoxia and exhibit activated K-ras signaling, progressive loss of PTEN, and tumorigenicity in vivo. Whereas UM-PDC1 form localized tumors, the UM-PDC2 metastasize to lungs in mice. In an order of progression, these models exhibit genomic instability marked by gross chromosomal rearrangements, centrosome-number variations, Aurora-kinase/H2AX colocalization, loss of primary cilia, and α-tubulin acetylation. The RNA sequencing of hypoxic models followed by qRT-PCR validation and gene-set enrichment identified Intestine-Specific Homeobox factor (ISX)-driven molecular pathway as an indicator PDAC aggressivness. TCGA-PAAD clinical data analysis showed high ISX expression correlation to poor survival of PDAC patients, particularly women. The functional studies showed ISX as a regulator of i) invasiveness and migratory potential and ii) VEGF, MMP2, and NFκB activation in PDAC cells. We suggest that ISX is a potential druggable target and newly developed spontaneous cell models are valuable tools for studying mechanism and testing therapies for PDAC.

Riluzole induces AR degradation via endoplasmic reticulum stress pathway in androgen-dependent and castration-resistant prostate cancer cells.

BACKGROUND: Prostate cancer (PCa) is diagnosed at the highest rate of all non-cutaneous male cancers in the United States. The androgen-dependent (AD) transcription factor, androgen receptor (AR), drives PCa-but inhibiting AR or androgen biosynthesis induces remission for only a short time. At which point, patients acquire more aggressive castration-resistant (CR) disease with re-activated AR-dependent signaling. To combat treatment resistance, down-regulating AR protein expression has been considered as a potential treatment strategy for CR-PCa. METHODS: AD- and CR-PCa cell lines were treated with the well-tolerated FDA-approved oral medicine, riluzole. Expression of full-length or wild-type AR (AR-FL) and constitutively active AR-splice variant 7 (AR-V7) was assessed by immunoblotting. AR-FL/AR-V7 activity was measured using qRT-PCR of AR-target genes. Cytoplasmic [Ca2+ ] levels were measured using a fluorescent Ca2+ indicator microplate assay. Markers of the endoplasmic reticulum stress (ERS) pathway and autophagy were assessed by immunoblotting. Direct interaction between AR and selective autophagy receptor p62 was demonstrated by co-immunoprecipitation. RESULTS: We demonstrate that riluzole downregulates AR-FL, mutant ARs, and AR-V7 proteins expression by protein degradation through ERS pathway and selective autophagy. Riluzole also significantly inhibited AR transcription activity by decreasing its target genes expression (PSA, TMPRSS2, and KLK2). CONCLUSIONS: We provide key mechanistic insights by which riluzole exerts its anti-tumorigenic effects and induces AR protein degradation via ERS pathways. Our findings support the potential utility of riluzole for treatment of PCa.

BMI1 Drives Metastasis of Prostate Cancer in Caucasian and African-American Men and Is A Potential Therapeutic Target: Hypothesis Tested in Race-specific Models.

PURPOSE: Metastasis is the major cause of mortality in prostate cancer patients. Factors such as genetic makeup and race play critical role in the outcome of therapies. This study was conducted to investigate the relevance of BMI1 in metastatic prostate cancer disease in Caucasian and African-Americans. EXPERIMENTAL DESIGN: We employed race-specific prostate cancer models, clinical specimens, clinical data mining, gene-microarray, transcription-reporter assay, chromatin-immunoprecipitation (ChIP), IHC, transgenic-(tgfl/fl) zebrafish, and mouse metastasis models. RESULTS: BMI1 expression was observed to be elevated in metastatic tumors (lymph nodes, lungs, bones, liver) of Caucasian and African-American prostate cancer patients. The comparative analysis of stage III/IV tumors showed an increased BMI1 expression in African-Americans than Caucasians. TCGA and NIH/GEO clinical data corroborated to our findings. We show that BMI1 expression (i) positively correlates to metastatic (MYC, VEGF, cyclin D1) and (ii) negative correlates to tumor suppressor (INKF4A/p16, PTEN) levels in tumors. The correlation was prominent in African-American tumors. We show that BMI1 regulates the transcriptional activation of MYC, VEGF, INKF4A/p16, and PTEN. We show the effect of pharmacological inhibition of BMI1 on the metastatic genome and invasiveness of tumor cells. Next, we show the anti-metastatic efficacy of BMI1-inhibitor in transgenic zebrafish and mouse metastasis models. Docetaxel as monotherapy has poor outcome on the growth of metastatic tumors. BMI1 inhibitor as an adjuvant improved the taxane therapy in race-based in vitro and in vivo models. CONCLUSIONS: BMI1, a major driver of metastasis, represents a promising therapeutic target for treating advanced prostate cancer in patients (including those belonging to high-risk group).

Reversion of epithelial-mesenchymal transition by a novel agent DZ-50 via IGF binding protein-3 in prostate cancer cells.

Dysregulation of transforming growth factor-ß1 (TGF-ß1) and insulin-like growth factor (IGF) axis has been linked to reactive stroma dynamics in prostate cancer progression. IGF binding protein-3 (IGFBP3) induction is initiated by stroma remodeling and could represent a potential therapeutic target for prostate cancer. In previous studies a lead quinazoline-based Doxazosin® derivative, DZ-50, impaired prostate tumor growth by targeting proteins involved in focal adhesion, anoikis resistance and epithelial-mesenchymal-transition (EMT). This study demonstrates that DZ-50 increased expression of the epithelial marker E-cadherin, and decreased the mesenchymal marker N-cadherin in human prostate cancer cells. In DU-145 cells, the effect of DZ-50 on EMT towards mesenchymal epithelial transition (MET) was inhibited by talin1 overexpression, a focal adhesion regulator promoting anoikis resistance and tumor invasion. DZ-50 treatment of human prostate cancer cells and cancer-associated fibroblasts (CAFs) downregulated IGFBP3 expression at mRNA and protein level. In TGF-ß1 responsive LNCaPTßRII, TGF-ß1 reversed DZ-50-induced MET by antagonizing the drug-induced decrease of nuclear IGFBP3. Furthermore, co-culture with CAFs promoted prostate cancer epithelial cell invasion, an effect that was significantly inhibited by DZ-50. Our findings demonstrate that the lead compound, DZ-50, inhibited the invasive properties of prostate cancer epithelial cells by targeting IGFBP3 and mediating EMT conversion to MET. This study integrated the mechanisms underlying the effect of DZ-50 and further supported the therapeutic value of this compound in the treatment of advanced metastatic prostate cancer.

Androgen receptor splice variants and prostate cancer: From bench to bedside.

Therapeutic interventions for advanced prostate cancer (PCa) center on inhibiting androgen receptor (AR) and downstream signaling pathways. Resistance to androgen deprivation therapy and/or AR antagonists is inevitable and molecular mechanisms driving castration-resistant PCa (CR-PCa) primarily involve alterations in AR expression and activity. Detailed molecular biology work over the past decade, discussed at length in this review article, has revealed several AR transcripts that result from alternative splicing. These AR splice variants are increased in cell and mouse models of CR-PCa and in CR-PCa tumors. Several AR variants lack the ligand binding domain, but retain their ability to bind DNA and activate transcription-linking constitutive AR function and therapeutic failure. ARV7 is the only variant endogenously detected at the protein level and thus has undergone more thorough molecular characterization. Clinical trials in PCa are currently investigating ARV7 utility as a biomarker and new therapeutics that inhibit ARV7 . Overall, this review will illustrate the historical perspectives of AR splice variant discovery using fundamental molecular biology techniques and how it changed the clinical approach to both therapeutic decisions and strategy. The body of work investigating AR splice variants in PCa represents a true example of translational research from bench to bedside.

Molecular mechanisms underlying resistance to androgen deprivation therapy in prostate cancer.

Prostate cancer (PCa) is the most widely diagnosed male cancer in the Western World and while low- and intermediate-risk PCa patients have a variety of treatment options, metastatic patients are limited to androgen deprivation therapy (ADT). This treatment paradigm has been in place for 75 years due to the unique role of androgens in promoting growth of prostatic epithelial cells via the transcription factor androgen receptor (AR) and downstream signaling pathways. Within 2 to 3 years of ADT, disease recurs-at which time, patients are considered to have castration-recurrent PCa (CR-PCa). A universal mechanism by which PCa becomes resistant to ADT has yet to be discovered. In this review article, we discuss underlying molecular mechanisms by which PCa evades ADT. Several major resistance pathways center on androgen signaling, including intratumoral and adrenal androgen production, AR-overexpression and amplification, expression of AR mutants, and constitutively-active AR splice variants. Other ADT resistance mechanisms, including activation of glucocorticoid receptor and impairment of DNA repair pathways are also discussed. New therapies have been approved for treatment of CR-PCa, but increase median survival by only 2-8 months. We discuss possible mechanisms of resistance to these new ADT agents. Finally, the practicality of the application of "precision oncology" to this continuing challenge of therapy resistance in metastatic or CR-PCa is examined. Empirical validation and clinical-based evidence are definitely needed to prove the superiority of "precision" treatment in providing a more targeted approach and curative therapies over the existing practices that are based on biological "cause-and-effect" relationship.

GRM1 is An Androgen-Regulated Gene and its Expression Correlates with Prostate Cancer Progression in Pre-Clinical Models.

PURPOSE: We recently demonstrated that glutamate receptor GRM1 was expressed at high levels in castration-resistant prostate cancer (CR-PCa) tissues and cells. Herein, we determined the relationship between GRM1 and AR, PSA, and tumor growth, remission, and recurrence in preclinical PCa models. The effect of alterations in GRM1 expression was also investigated on PCa cell growth, migration and invasion. EXPERIMENTAL DESIGN: We used quantitative gene expression and immunohistochemistry to define the temporal association between GRM1 expression and AR, PSA, and tumor growth during CR progression in CWR22 (n = 59) and LuCaP 35 (n = 12) PCa xenografts. The effect of alterations in GRM1 expression levels on growth, migration, and invasion was investigated in GRM1-overexpressed or -silenced PCa cell lines. The effect of DHT on GRM1 expression was determined in the presence or absence of the antiandrogen bicalutamide. RESULTS: We found that GRM1 transcript and tissue expression directly correlated with growth and AR and PSA expression in hormone-sensitive (HS), castrated, and CR tumor xenografts. GRM1 overexpression or silencing directly correlated with PCa cell proliferation, migration, and invasion. DHT increased GRM1 expression via an AR-dependent manner in HS- and CR-PCa cell lines. CONCLUSIONS: This is a first report of GRM1 as an androgen and AR-target gene. GRM1 expression directly correlated with tumor growth, regression, and recurrence and may contribute to CR-progression of PCa in preclinical models. Further studies are needed to define the utility of GRM1 as a druggable target or biomarker for PCa.

Characterization of fibroblast-free CWR-R1ca castration-recurrent prostate cancer cell line.

BACKGROUND: The previously established CWR-R1 cell line has been used as an in vitro model representing castration-recurrent prostate cancer. Microscopic observation of subconfluent cells demonstrated two distinct cellular morphologies: polygonal closely aggregated epithelial cells surrounded by bipolar fibroblastic cells with long processes. This study sought to establish and characterize a fibroblast-free derivative of the CWR-R1 cell line. METHODS: The CWR-R1ca cell line was established from CWR-R1 cells by removing fibroblasts using multiple cycles of short-term trypsinization, cloning, and pooling single-cell colonies. Authentication of fibroblast-free CWR-R1ca cells was demonstrated by analyzing the expression of cytodifferentiation and prostate-associated markers, DNA and cytogenetic profiling, and growth pattern in the absence or presence of androgen. RESULTS: CWR-R1ca is an androgen-sensitive cell line that expresses the androgen receptor (AR) and its splice variant 7 and the luminal epithelia markers, CK-8, CK-18, and c-Met. CWR-R1fb fibroblasts isolated from CWR-R1 cells express AR, hepatocyte growth factor-α, and mouse ß-actin but not AR-V7 or epithelial markers. Cytogenetic analysis of CWR-R1ca cells revealed a hyperdiploid male with numerical gains in chromosomes 1, 7, 8, 10, 11, and 12, deletion of one chromosome 2 allele, structural abnormalities that include der(1)t(1:4), der(4)t(2:4), der(10)t(4:10), and an unbalanced reciprocal translocation between chromosome 6 and 14. DNA-profiling revealed that CWR-R1ca cells had significant short-tandem repeat marker homology with CWR22Pc and CWR22Rv1 cell lines, which indicated lineage derivation from CWR22 prostate cancer xenografts. CWR-R1ca cells were responsive to the growth stimulatory effects of dihydrotestosterone (DHT) in the femtomolar range. CONCLUSION: This study establishes CWR-R1ca cells as a fibroblast-free derivative of the castration-recurrent CWR-R1 cell line. Prostate 76:1067-1077, 2016. © 2016 Wiley Periodicals, Inc.

Mitochondrial dysfunction-mediated apoptosis resistance associates with defective heat shock protein response in African-American men with prostate cancer.

BACKGROUND: African-American (AA) patients with prostate cancer (PCa) respond poorly to current therapy compared with Caucasian American (CA) PCa patients. Although underlying mechanisms are not defined, mitochondrial dysfunction is a key reason for this disparity. METHODS: Cell death, cell cycle, and mitochondrial function/stress were analysed by flow cytometry or by Seahorse XF24 analyzer. Expression of cellular proteins was determined using immunoblotting and real-time PCR analyses. Cell survival/motility was evaluated by clonogenic, cell migration, and gelatin zymography assays. RESULTS: Glycolytic pathway inhibitor dichloroacetate (DCA) inhibited cell proliferation in both AA PCa cells (AA cells) and CA PCa cells (CA cells). AA cells possess reduced endogenous reactive oxygen species, mitochondrial membrane potential (mtMP), and mitochondrial mass compared with CA cells. DCA upregulated mtMP in both cell types, whereas mitochondrial mass was significantly increased in CA cells. DCA enhanced taxol-induced cell death in CA cells while sensitising AA cells to doxorubicin. Reduced expression of heat shock proteins (HSPs) was observed in AA cells, whereas DCA induced expression of CHOP, C/EBP, HSP60, and HSP90 in CA cells. AA cells are more aggressive and metastatic than CA cells. CONCLUSIONS: Restoration of mitochondrial function may provide new option for reducing PCa health disparity among American men.

Therapeutic Rationales, Progresses, Failures, and Future Directions for Advanced Prostate Cancer.

Patients with localized prostate cancer (PCa) have several therapeutic options with good prognosis. However, survival of patients with high-risk, advanced PCa is significantly less than patients with early-stage, organ-confined disease. Testosterone and other androgens have been directly linked to PCa progression since 1941. In this review, we chronicle the discoveries that led to modern therapeutic strategies for PCa. Specifically highlighted is the biology of androgen receptor (AR), the nuclear receptor transcription factor largely responsible for androgen-stimulated and castrate-recurrent (CR) PCa. Current PCa treatment paradigms can be classified into three distinct but interrelated categories: targeting AR at pre-receptor, receptor, or post-receptor signaling. The continuing challenge of disease relapse as CR and/or metastatic tumors, destined to occur within three years of the initial treatment, is also discussed. We conclude that the success of PCa therapies in the future depends on targeting molecular mechanisms underlying tumor recurrence that still may affect AR at pre-receptor, receptor, and post-receptor levels.