Genomic Correlates of Prostate-Specific Membrane Antigen Expression and Response to 177Lu-PSMA-617: A Retrospective Multicenter Cohort Study.

PURPOSE: While 177Lu-PSMA-617 (LuPSMA) is an effective therapy for many patients with metastatic castration-resistant prostate cancer (mCRPC), biomarkers associated with outcomes are not well defined. We hypothesized that prostate cancer mutational profile may associate with clinical activity of LuPSMA. We devised a study to evaluate associations between mCRPC mutational profile with LuPSMA clinical outcomes. METHODS: This was a multicenter retrospective analysis of patients with mCRPC with next-generation sequencing (NGS) who received LuPSMA. PSA50 response (ie, ≥50% decline in prostate-specific antigen [PSA]) rate, PSA progression free survival (PSA PFS), and overall survival (OS) were compared between genetically defined subgroups. RESULTS: One hundred twenty-six patients with NGS results who received at least one cycle of LuPSMA were identified. The median age was 73 (IQR, 68-78) years, 124 (98.4%) received ≥1 prior androgen receptor-signaling inhibitor, and 121 (96%) received ≥1 taxane-based chemotherapy regimen. Fifty-eight (46%) patients with a DNA damage repair gene mutation (DNA damage response group) and 59 (46.8%) with a mutation in TP53, RB1, or PTEN tumor suppressor genes (TSG group) were identified. After adjusting for relevant confounders, the presence of ≥1 TSG mutation was associated with shorter PSA PFS (hazard ratio [HR], 1.93 [95% CI, 1.05 to 3.54]; P = .034) and OS (HR, 2.65 [95% CI, 1.15 to 6.11]; P = .023). There was improved OS favoring the DNA damage response group (HR, 0.37 [95% CI, 0.14 to 0.97]; P = .044) on multivariable analysis. Univariate analysis of patients with ATM mutations had significantly higher rates of PSA50 response, PSA PFS, and OS. CONCLUSION: Outcomes on LuPSMA varied on the basis of mutational profile. Prospective studies to define the clinical activity of LuPSMA in predefined genomic subgroups are justified.

A combinatorial genetic strategy for exploring complex genotype-phenotype associations in cancer.

Available genetically defined cancer models are limited in genotypic and phenotypic complexity and underrepresent the heterogeneity of human cancer. Here, we describe a combinatorial genetic strategy applied to an organoid transformation assay to rapidly generate diverse, clinically relevant bladder and prostate cancer models. Importantly, the clonal architecture of the resultant tumors can be resolved using single-cell or spatially resolved next-generation sequencing to uncover polygenic drivers of cancer phenotypes.

Combinatorial genetic strategy accelerates the discovery of cancer genotype-phenotype associations.

Available genetically-defined cancer models are limited in genotypic and phenotypic complexity and underrepresent the heterogeneity of human cancer. Herein, we describe a combinatorial genetic strategy applied to an organoid transformation assay to rapidly generate diverse, clinically relevant bladder and prostate cancer models. Importantly, the clonal architecture of the resultant tumors can be resolved using single-cell or spatially resolved next-generation sequencing to uncover polygenic drivers of cancer phenotypes.

Transcriptional-translational conflict is a barrier to cellular transformation and cancer progression.

We uncover a tumor-suppressive process in urothelium called transcriptional-translational conflict caused by deregulation of the central chromatin remodeling component ARID1A. Loss of Arid1a triggers an increase in a nexus of pro-proliferation transcripts, but a simultaneous inhibition of the eukaryotic elongation factor 2 (eEF2), which results in tumor suppression. Resolution of this conflict through enhancing translation elongation speed enables the efficient and precise synthesis of a network of poised mRNAs resulting in uncontrolled proliferation, clonogenic growth, and bladder cancer progression. We observe a similar phenomenon in patients with ARID1A-low tumors, which also exhibit increased translation elongation activity through eEF2. These findings have important clinical implications because ARID1A-deficient, but not ARID1A-proficient, tumors are sensitive to pharmacologic inhibition of protein synthesis. These discoveries reveal an oncogenic stress created by transcriptional-translational conflict and provide a unified gene expression model that unveils the importance of the crosstalk between transcription and translation in promoting cancer.

Allogeneic stem cell transplantation in patients with a prior history of prostate cancer.

A retrospective analysis of 25 patients with a history of prostate cancer (PC) who subsequently underwent allogeneic hematopoietic cell transplantation (HCT) for treatment of a hematologic malignancy was performed. Median patient age was 66.7 years. Median duration from the diagnosis of PC to HCT was 4.2 years. Twenty-three patients had Gleason group 1 or 2 disease. Therapy included prostatectomy (n = 13) and external beam or brachytherapy (n = 9). Hematologic diagnoses included both myeloid (n = 15) and lymphoid neoplasms (n = 10). Twenty-four patients received either a nonmyeloablative or reduced intensity conditioning regimen. GVHD prophylaxis included a calcineurin inhibitor and mycophenolate mofetil ± sirolimus. Twenty patients had HLA-matched sibling or HLA-matched unrelated donors; five patients had HLA-mismatched donors. Eleven patients are alive, and 14 have died. Median survival was 2.5 years (range, .02-12.6 years). The major cause of death was hematologic relapse. Only one patient had evidence of recurrent PC, occurring 1.5 years posttransplant. In carefully selected patients with a prior history of PC, there was no evidence of rapid recurrence of the solid tumor (ST) after HCT. PC patients who are in remission from their ST or have control of their disease on therapy should be considered eligible for HCT.

Phase II trial of CV301 vaccine combined with atezolizumab in advanced urothelial carcinoma.

CV301 comprises recombinant poxviruses, Modified Vaccinia Ankara (MVA) and Fowlpox (FPV), encoding CEA, MUC-1, and co-stimulatory Molecules (TRICOM) ICAM-1, LFA-3, and B7-1. MVA-BN-CV301 is used for priming and FPV-CV301 is used for boosting. A Phase 2, single-arm trial was designed to evaluate CV301 plus atezolizumab as first-line treatment for cisplatin-ineligible advanced urothelial carcinoma (aUC) (Cohort 1) or progressing after platinum chemotherapy (Cohort 2). MVA-CV301 was given subcutaneously (SC) on Days 1 and 22 and FPV-CV301 SC from day 43 every 21 days for 4 doses, then tapered gradually over up to 2 years. Atezolizumab 1200 mg IV was given every 21 days. The primary endpoint was objective response rate (ORR). Overall, 43 evaluable patients received therapy: 19 in Cohort 1; 24 in Cohort 2; nine experienced ≥ Grade 3 therapy-related adverse events. In Cohort 1, one had partial response (PR) (ORR 5.3%, 90% CI 0.3, 22.6). In Cohort 2, 1 complete response and 1 PR were noted (ORR 8.3%, 90% CI 1.5, 24.0). The trial was halted for futility. Patients exhibiting benefit demonstrated T-cell response to CEA and MUC-1. The trial illustrates the challenges in the development of vaccines, which should be guided by robust preclinical data.

ASSESSMENT OF CELL SURFACE TARGETS IN METASTATIC PROSTATE CANCER: EXPRESSION LANDSCAPE AND MOLECULAR CORRELATES.

Therapeutic approaches targeting proteins on the surface of cancer cells have emerged as an important strategy for precision oncology. To fully capitalize on the potential impact of drugs targeting surface proteins, detailed knowledge about the expression patterns of the target proteins in tumor tissues is required. In castration-resistant prostate cancer (CRPC), agents targeting prostate-specific membrane antigen (PSMA) have demonstrated clinical activity. However, PSMA expression is lost in a significant number of CRPC tumors, and the identification of additional cell surface targets is necessary in order to develop new therapeutic approaches. Here, we performed a comprehensive analysis of the expression and co-expression patterns of trophoblast cell-surface antigen 2 (TROP2), delta-like ligand 3 (DLL3), and carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) in CRPC samples from a rapid autopsy cohort. We show that DLL3 and CEACAM5 exhibit the highest expression in neuroendocrine prostate cancer (NEPC), while TROP2 is expressed across different CRPC molecular subtypes, except for NEPC. We observed variable intra-tumoral and inter-tumoral heterogeneity and no dominant metastatic site predilections for TROP2, DLL3, and CEACAM5. We further show that AR amplifications were associated with higher expression of PSMA and TROP2 but lower DLL3 and CEACAM5 levels. Conversely, PSMA and TROP2 expression was lower in RB1-altered tumors. In addition to genomic alterations, we demonstrate a tight correlation between epigenetic states, particularly histone H3 lysine 27 methylation (H3K27me3) at the transcriptional start site and gene body of TACSTD2 (encoding TROP2), DLL3, and CEACAM5, and their respective protein expression in CRPC patient-derived xenografts. Collectively, these findings provide novel insights into the patterns and determinants of expression of TROP2, DLL3, and CEACAM5 with important implications for the clinical development of cell surface targeting agents in CRPC.

Effect of Androgen Suppression on Clinical Outcomes in Hospitalized Men With COVID-19: The HITCH Randomized Clinical Trial.

Importance: SARS-CoV-2 entry requires the TMPRSS2 cell surface protease. Antiandrogen therapies reduce expression of TMPRSS2. Objective: To determine if temporary androgen suppression induced by degarelix improves clinical outcomes of inpatients hospitalized with COVID-19. Design, Setting, and Participants: The Hormonal Intervention for the Treatment in Veterans With COVID-19 Requiring Hospitalization (HITCH) phase 2, placebo-controlled, double-blind, randomized clinical trial compared efficacy of degarelix plus standard care vs placebo plus standard care on clinical outcomes in men hospitalized with COVID-19 but not requiring invasive mechanical ventilation. Inpatients were enrolled at 14 Department of Veterans Affairs hospitals from July 22, 2020, to April 8, 2021. Data were analyzed from August 9 to October 15, 2021. Interventions: Patients stratified by age, history of hypertension, and disease severity were centrally randomized 2:1 to degarelix, (1-time subcutaneous dose of 240 mg) or a saline placebo. Standard care included but was not limited to supplemental oxygen, antibiotics, vasopressor support, peritoneal dialysis or hemodialysis, intravenous fluids, remdesivir, convalescent plasma, and dexamethasone. Main Outcomes and Measures: The composite primary end point was mortality, ongoing need for hospitalization, or requirement for mechanical ventilation at day 15 after randomization. Secondary end points were time to clinical improvement, inpatient mortality, length of hospitalization, duration of mechanical ventilation, time to achieve a temperature within reference range, maximum severity of COVID-19, and the composite end point at 30 days. Results: The trial was stopped for futility after the planned interim analysis, at which time there were 96 evaluable patients, including 62 patients randomized to the degarelix group and 34 patients in the placebo group, out of 198 initially planned. The median (range) age was 70.5 (48-85) years. Common comorbidities included chronic obstructive pulmonary disorder (15 patients [15.6%]), hypertension (75 patients [78.1%]), cardiovascular disease (27 patients [28.1%]), asthma (12 patients [12.5%]), diabetes (49 patients [51.0%]), and chronic respiratory failure requiring supplemental oxygen at baseline prior to COVID-19 (9 patients [9.4%]). For the primary end point, there was no significant difference between the degarelix and placebo groups (19 patients [30.6%] vs 9 patients [26.5%]; P = .67). Similarly, no differences were observed between degarelix and placebo groups in any secondary end points, including inpatient mortality (11 patients [17.7%] vs 6 patients [17.6%]) or all-cause mortality (11 patients [17.7%] vs 7 patents [20.6%]). There were no differences between degarelix and placebo groups in the overall rates of adverse events (13 patients [21.0%] vs 8 patients [23.5%) and serious adverse events (19 patients [30.6%] vs 13 patients [32.4%]), nor unexpected safety concerns. Conclusions and Relevance: In this randomized clinical trial of androgen suppression vs placebo and usual care for men hospitalized with COVID-19, degarelix did not result in amelioration of COVID-19 severity. Trial Registration: ClinicalTrials.gov Identifier: NCT04397718.

A Prospective Study of a Resorbable Intravesical Fiducial Marker for Bladder Cancer Radiation Therapy.

Purpose: We conducted a prospective pilot study to evaluate safety and feasibility of TraceIT, a resorbable radiopaque hydrogel, to improve image guidance for bladder cancer radiation therapy (RT). Methods and Materials: Patients with muscle invasive bladder cancer receiving definitive RT were eligible. TraceIT was injected intravesically around the tumor bed during maximal transurethral resection of bladder tumor. The primary endpoint was the difference between radiation treatment planning margin on daily cone beam computed tomography based on alignment to TraceIT versus standard-of-care pelvic bone anatomy. The Van Herk margin formula was used to determine the optimal planning target volume margin. TraceIT visibility, recurrence rates, and survival were estimated by Kaplan-Meier method. Toxicity was measured by Common Terminology Criteria for Adverse Events version 4.03. Results: The trial was fully accrued and 15 patients were analyzed. TraceIT was injected in 4 sites/patient (range, 4-6). Overall, 94% (95% confidence interval [CI], 90%-98%) of injection sites were radiographically visible at RT initiation versus 71% (95% CI, 62%-81%) at RT completion. The median duration of radiographic visibility for injection sites was 106 days (95% CI, 104-113). Most patients were treated with a standard split-course approach with initial pelvic radiation fields, then midcourse repeat transurethral resection of bladder tumor followed by bladder tumor bed boost fields, and 14/15 received concurrent chemotherapy. Alignment to fiducials could allow for reduced planning target volume margins (0.67 vs 1.56 cm) for the initial phase of RT, but not for the boost (1.01 vs 0.96 cm). This allowed for improved target coverage (D95% 80%-83% to 91%-94%) for 2 patients retrospectively planned with both volumetric-modulated arc therapy and 3-dimensional conformal RT. At median follow-up of 22 months, no acute or late complications attributable to TraceIT placement occurred. No patients required salvage cystectomy. Conclusions: TraceIT intravesical fiducial placement is safe and feasible and may facilitate tumor bed delineation and targeting in patients undergoing RT for localized muscle invasive bladder cancer. Improved image guided treatment may facilitate strategies to improve local control and minimize toxicity.

A phase 1 study to assess the safety, pharmacokinetics, and anti-tumor activity of the androgen receptor n-terminal domain inhibitor epi-506 in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: EPI-506 is the first of a new class of drugs targeting the N-terminal domain (NTD) of the androgen receptor (AR), potentially overcoming known resistance mechanisms to androgen receptor pathway inhibitors (ARPIs) among men with metastatic castration resistant prostate cancer (mCRPC). METHODS: Patients with mCRPC who had progressed on prior ARPI were enrolled in this phase 1 open-label, adaptive 3 + 3 dose escalation study. The primary outcome was safety and tolerability of oral EPI-506. Secondary objectives included determination of the maximal tolerated dose (MTD), pharmacokinetic profile, and antitumor efficacy. RESULTS: 28 mCRPC patients were enrolled into 7 dose cohorts of EPI-506 ranging from 80-3600 mg given once daily and 1800 mg given twice daily. Six DLTs occurred in 4 patients; Grade 4 elevated amylase; Grade 3 abdominal pain; Grade 3 elevated ALT and Grade 3 elevated AST; Grade 2 nausea and Grade 1 vomiting which resulted in study drug intake of < 75% of the expected dose during the DLT assessment period. The most common drug-related adverse events included diarrhea, nausea and fatigue. Six patients had a PSA decline not meeting PSA response criteria. The study was terminated prior to reaching the MTD due to poor oral bioavailability. CONCLUSIONS: This phase 1 trial established the safety of EPI-506 and provides proof of concept for targeting the AR NTD. Next generation compounds with improved bioavailability and potency are in clinical development.

Genomic attributes of homology-directed DNA repair deficiency in metastatic prostate cancer.

Cancers with homology-directed DNA repair (HRR) deficiency exhibit high response rates to poly(ADP-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy. Though mutations disrupting BRCA1 and BRCA2 associate with HRR deficiency (HRRd), patterns of genomic aberrations and mutation signatures may be more sensitive and specific indicators of compromised repair. Here, we evaluated whole-exome sequences from 418 metastatic prostate cancers (mPCs) and determined that one-fifth exhibited genomic characteristics of HRRd that included Catalogue Of Somatic Mutations In Cancer mutation signature 3. Notably, a substantial fraction of tumors with genomic features of HRRd lacked biallelic loss of a core HRR-associated gene, such as BRCA2. In this subset, HRRd associated with loss of chromodomain helicase DNA binding protein 1 but not with mutations in serine-protein kinase ATM, cyclin dependent kinase 12, or checkpoint kinase 2. HRRd genomic status was strongly correlated with responses to PARPi and platinum chemotherapy, a finding that supports evaluating biomarkers reflecting functional HRRd for treatment allocation.

Patterns and timing of perioperative blood transfusion and association with outcomes after radical cystectomy.

BACKGROUND: Perioperative blood transfusion (PBT) has been associated with worse outcomes across tumor types, including bladder cancer. We report our institutional experience with PBT utilization in the setting of radical cystectomy (RC) for patients with bladder cancer, exploring whether timing of PBT receipt influences perioperative and oncologic outcomes. METHODS: Consecutive patients with bladder cancer treated with RC were identified. PBT was defined as red blood cell transfusion during RC or the postoperative admission. Clinicopathologic and peri and/or postoperative parameters were extracted and compared between patients who did and did not receive PBT using Mann Whitney U Test, chi-square, and log-rank test. Overall (OS) and recurrence-free survival (RFS) were estimated with the Kaplan Meier method. Univariate/multivariate logistic and Cox proportional hazards regression were used to identify variables associated with postoperative and oncologic outcomes, respectively. RESULTS: The cohort consisted of 747 patients (77% men; median age 67 years). Median follow-up was 61.5 months (95% CI 55.8-67.2) At least one postoperative complication (90-day morbidity) occurred in 394 (53%) patients. Median OS and RFS were 91.8 months (95% CI: 76.0-107.6) and 66.0 months (95% CI: 48.3-83.7), respectively. On multivariate analysis, intraoperative, but not postoperative, BT was independently associated with shorter OS (HR: 1.74, 95% CI: 1.32-2.29) and RFS (HR: 1.55, 95%CI: 1.20-2.01), after adjusting for relevant clinicopathologic variables. PBT (intra- or post- operative) was significantly associated with prolonged postoperative hospitalization ≥10 days. CONCLUSIONS: Intraoperative BT was associated with inferior OS and RFS, and PBT overall was associated with prolonged hospitalization following RC. Further studies are needed to validate this finding and explore potential causes for this observation.

Response to Neoadjuvant Chemotherapy and Survival in Micropapillary Urothelial Carcinoma: Data From a Tertiary Referral Center and the Surveillance, Epidemiology, and End Results (SEER) Program.

BACKGROUND: Micropapillary urothelial carcinoma (MPC) is a rare urothelial carcinoma variant with conflicting data guiding clinical practice. In this study, we explored oncologic outcomes in relation to neoadjuvant chemotherapy (NAC) in a retrospective cohort of patients with MPC, alongside data from Surveillance, Epidemiology, and End Results (SEER)-Medicare. PATIENTS AND METHODS: We retrospectively identified patients with MPC or conventional urothelial carcinoma (CUC) without any variant histology undergoing radical cystectomy (RC) in our institution (2003-2018). SEER-Medicare was also queried to identify patients diagnosed with MPC (2004-2015). Clinicopathologic data and treatment modalities were extracted. Overall survival (OS) was estimated with the Kaplan-Meier method. Mann-Whitney-Wilcoxon and chi-square tests were used for comparative analysis and Cox regression for identifying clinical covariates associated with OS. RESULTS: Our institutional database yielded 46 patients with MPC and 457 with CUC. In SEER-Medicare, 183 patients with MPC were identified, and 63 (34%) underwent RC. In the institutional cohort, patients with MPC had significantly higher incidence of cN+ (17% vs. 8%), pN+ stage (30% vs. 17%), carcinoma-in-situ (43% vs. 25%), and lymphovascular invasion (30% vs. 16%) at RC versus those with CUC (all P < .05). Pathologic complete response (ypT0N0) to NAC was 33% for MPC and 35% for CUC (P = .899). Median OS was lower for institutional MPC versus CUC in univariate analysis (43.6 vs. 105.3 months, P = .006); however, MPC was not independently associated with OS in the multivariate model. Median OS was 25 months in the SEER MPC cohort for patients undergoing RC, while NAC was not associated with improved OS in that group. CONCLUSION: Pathologic response to NAC was not significantly different between MPC and CUC, while MPC histology was not an independent predictor of OS. Further studies are needed to better understand biological mechanisms behind its aggressive features as well as the role of NAC in this histology variant.

Downstaging of Muscle-Invasive Bladder Cancer Using Neoadjuvant Gemcitabine and Cisplatin or Dose-Dense Methotrexate, Vinblastine, Doxorubicin, and Cisplatin as Single Regimens or as Switch Therapy Modalities.

BACKGROUND: Consensus guidelines recommend gemcitabine and cisplatin (GC) or dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) as equally preferable neoadjuvant chemotherapy before cystectomy for muscle-invasive bladder cancer. This study sought to compare the ability of GC and ddMVAC to achieve pathologic response; and to evaluate the benefit of switching regimens after 1 or 2 cycles of the other. PATIENTS AND METHODS: Patients aged ≥ 18 with muscle-invasive bladder cancer (≥ cT2) and who had received either GC or ddMVAC as neoadjuvant chemotherapy followed by cystectomy were retrospectively evaluated using the electronic medical record. Patients who received 1 or 2 cycles of one regimen followed by several cycles of the other regimen before cystectomy were classified as switch therapy patients. This study assessed the rates of pathologic complete response (pCR) and any degree of downstaging. RESULTS: Among 109 patients who received GC or ddMVAC, 7 (21%) of 33 ddMVAC patients demonstrated pCR, and 19 (25%) of 76 GC patients demonstrated pCR (odds ratio, 1.24; 95% confidence interval, 0.46-3.31; P = .67). Downstaging rates were 39% for ddMVAC and 50% for GC (P = .31). Thirty-three of 36 patients aged ≥ 70 years received GC (P < .001). Four of 7 patients treated with switch therapy showed downstaging, and 2 of 7 experienced pCR. CONCLUSION: There was no difference in pCR rates between GC and ddMVAC, and patients were most often able to receive 3 or 4 cycles of treatment. Switch therapy may be of benefit in patients whose disease has a poor initial response.

Plasmacytoid urothelial carcinoma: response to chemotherapy and oncologic outcomes.

BACKGROUND: Plasmacytoid urothelial carcinoma is a rare bladder cancer variant with scarce data on outcomes and prognostic factors. OBJECTIVE: We report our institutional experience with this histology to determine response to neoadjuvant chemotherapy, definitive surgery and survival. METHODS: We conducted a retrospective chart review of consecutive patients with plasmacytoid, as well as conventional urothelial carcinoma (for comparison) seen in our institution (2007 - 2018). Baseline characteristics, clinicopathologic and treatment data were captured. T-test, chi-squared and log-rank test was used for group comparison. Kaplan Meier method was used for estimation of overall survival and Cox regression for identification of prognostic factors. RESULTS: 64 patients with plasmacytoid and 418 with conventional urothelial histology were identified; 53% of those with plasmacytoid presented with cT3/4 stage and 67% underwent extirpative surgery. Patients with plasmacytoid histology had higher rates of pT3/4 (65% vs. 28%), nodal disease (37% vs. 16%) and positive surgical margins (23% vs. 5%) compared to urothelial group (p < 0.01), as well as higher incidence of post-operative recurrence (47% vs. 29%, p = 0.05) and lower ypT0N0 rates after neoadjuvant chemotherapy (10% vs. 33%, p = 0.03). Plasmacytoid histology was associated with lower median overall survival compared to conventional urothelial (24 vs. 154 months, p < 0.01). CONCLUSIONS: Plasmacytoid urothelial carcinoma frequently presented with advanced stage at diagnosis and extirpative surgery, poor pathologic response to neoadjuvant chemotherapy, and inferior outcomes, when compared to conventional urothelial. Prospective trials evaluating upfront cystectomy versus preoperative chemotherapy and/or novel treatments should be considered.

Genomic distinctions between metastatic lower and upper tract urothelial carcinoma revealed through rapid autopsy.

BACKGROUND: Little is known about the genomic differences between metastatic urothelial carcinoma (LTUC) and upper tract urothelial carcinoma (UTUC). We compare genomic features of primary and metastatic UTUC and LTUC tumors in a cohort of patients with end stage disease. METHODS: We performed whole exome sequencing on matched primary and metastatic tumor samples (N=37) from 7 patients with metastatic UC collected via rapid autopsy. Inter- and intra-patient mutational burden, mutational signatures, predicted deleterious mutations, and somatic copy alterations (sCNV) were analyzed. RESULTS: We investigated 3 patients with UTUC (3 primary samples, 13 metastases) and 4 patients with LTUC (4 primary samples, 17 metastases). We found that sSNV burden was higher in metastatic LTUC compared to UTUC. Moreover, the APOBEC mutational signature was pervasive in metastatic LTUC and less so in UTUC. Despite a lower overall sSNV burden, UTUC displayed greater inter- and intra-individual genomic distances at the copy number level between primary and metastatic tumors than LTUC. Our data also indicate that metastatic UTUC lesions can arise from small clonal populations present in the primary cancer. Importantly, putative druggable mutations were found across patients with the majority shared across all metastases within a patient. CONCLUSIONS: Metastatic UTUC demonstrated a lower overall mutational burden but greater structural variability compared to LTUC. Our findings suggest that metastatic UTUC displays a greater spectrum of copy number divergence from LTUC. Importantly, we identified druggable lesions shared across metastatic samples, which demonstrate a level of targetable homogeneity within individual patients.

Genomic correlates of clinical outcome in advanced prostate cancer.

Heterogeneity in the genomic landscape of metastatic prostate cancer has become apparent through several comprehensive profiling efforts, but little is known about the impact of this heterogeneity on clinical outcome. Here, we report comprehensive genomic and transcriptomic analysis of 429 patients with metastatic castration-resistant prostate cancer (mCRPC) linked with longitudinal clinical outcomes, integrating findings from whole-exome, transcriptome, and histologic analysis. For 128 patients treated with a first-line next-generation androgen receptor signaling inhibitor (ARSI; abiraterone or enzalutamide), we examined the association of 18 recurrent DNA- and RNA-based genomic alterations, including androgen receptor (AR) variant expression, AR transcriptional output, and neuroendocrine expression signatures, with clinical outcomes. Of these, only RB1 alteration was significantly associated with poor survival, whereas alterations in RB1, AR, and TP53 were associated with shorter time on treatment with an ARSI. This large analysis integrating mCRPC genomics with histology and clinical outcomes identifies RB1 genomic alteration as a potent predictor of poor outcome, and is a community resource for further interrogation of clinical and molecular associations.

Effects of luteinizing hormone receptor signaling in prostate cancer cells.

BACKGROUND: The importance of androgen signaling in prostate cancer (PC) is well described and prostate cancer cells retain the ability to directly synthesize androgens. Luteinizing hormone (LH) can induce expression of steroidogenic enzymes and trigger androgen production, but the regulation of this process is not well-described. Here, we explored the impact of silencing LH receptor (LHR) silencing on androgen synthesis and on several relevant signaling pathways in PC. METHODS: LHR mRNA and protein expression was evaluated in LNCaP PC cells treated with LHR-siRNA. MTS assay was used to measure the effect of LHR-siRNA on proliferation in LNCaP and 22RV1 PC cells. Treated LNCaP and LAPC-3 cells were also assayed for differences in androgen synthesis and expression of steroidogenic enzymes, PSA, AR, and critical signaling molecules including PKA, ERK1/2, PI3K, AKT2, and HER2. RESULTS: We confirmed that functional LHR is expressed in both androgen-sensitive and castrate-resistant PC specimens. Treatment with LHR-siRNA effectively silenced LHR gene and protein expression and prevented LH-mediated proliferation and androgen synthesis in prostate cancer cells. LHR silencing also downregulated expression of AR, PSA, PKA, ERK1/2, PI3K, AKT2, and HER2. CONCLUSION: Collectively, these data demonstrate that silencing LHR expression suppresses androgen synthesis and signaling and the LH-LHR pathway may represent a viable therapeutic strategy in PC.

Abiraterone treatment in castration-resistant prostate cancer selects for progesterone responsive mutant androgen receptors.

PURPOSE: The CYP17A1 inhibitor abiraterone markedly reduces androgen precursors and is thereby effective in castration-resistant prostate cancer (CRPC). However, abiraterone increases progesterone, which can activate certain mutant androgen receptors (AR) identified previously in flutamide-resistant tumors. Therefore, we sought to determine if CYP17A1 inhibitor treatment selects for progesterone-activated mutant ARs. EXPERIMENTAL DESIGN: AR was examined by targeted sequencing in metastatic tumor biopsies from 18 patients with CRPC who were progressing on a CYP17A1 inhibitor (17 on abiraterone, 1 on ketoconazole), alone or in combination with dutasteride, and by whole-exome sequencing in residual tumor in one patient treated with neoadjuvant leuprolide plus abiraterone. RESULTS: The progesterone-activated T878A-mutant AR was present at high allele frequency in 3 of the 18 CRPC cases. It was also present in one focus of resistant tumor in the neoadjuvant-treated patient, but not in a second clonally related resistant focus that instead had lost one copy of PTEN and both copies of CHD1. The T878A mutation appeared to be less common in the subset of patients with CRPC treated with abiraterone plus dutasteride, and transfection studies showed that dutasteride was a more potent direct antagonist of the T878A versus the wild-type AR. CONCLUSIONS: These findings indicate that selection for tumor cells expressing progesterone-activated mutant ARs is a mechanism of resistance to CYP17A1 inhibition.

The basic biochemistry and molecular events of hormone therapy.

Data regarding the molecular response of prostate cancer to hormone therapy continue to emerge, identifying a complex network of autocrine and paracrine signaling events mediating the tumor response to androgen suppression. Emerging data provide insight into cellular pathways important in the apoptotic response to therapy, including the transforming growth factor-beta, insulin-like growth factor-1, and vascular endothelial growth factor signaling axes. They also reveal mechanisms of direct antitumor cytotoxicity mediated by various hormonal agents and highlight the importance of developing antiandrogens capable of irreversibly inhibiting the androgen receptor. Accumulated data emphasize the presence of residual androgens and persistent activation of androgen receptor signaling in advanced prostate tumors despite castration. These factors suggest that a multitargeted treatment approach designed to ablate all contributions to the androgen receptor signaling axis within the prostate tumor microenvironment will be required in order for hormonal therapy to achieve optimal antitumor efficacy.