Protein Kinase N1 control of androgen-responsive serum response factor action provides rationale for novel prostate cancer treatment strategy

Sustained reliance on androgen receptor (AR) after failure of AR-targeting androgen deprivation therapy (ADT) prevents effective treatment of castration-recurrent (CR) prostate cancer (CaP). Interfering with the molecular machinery by which AR drives CaP progression may be an alternative therapeutic strategy but its feasibility remains to be tested. Here, we explore targeting the mechanism by which AR, via RhoA, conveys androgen-responsiveness to serum response factor (SRF), which controls aggressive CaP behavior and is maintained in CR-CaP. Following a siRNA screen and candidate gene approach, RNA-Seq studies confirmed that the RhoA effector Protein Kinase N1 (PKN1) transduces androgen-responsiveness to SRF. Androgen treatment induced SRF-PKN1 interaction, and PKN1 knockdown or overexpression severely impaired or stimulated, respectively, androgen regulation of SRF target genes. PKN1 overexpression occurred during clinical CR-CaP progression, and hastened CaP growth and shortened CR-CaP survival in orthotopic CaP xenografts. PKN1's effects on SRF relied on its kinase domain. The multikinase inhibitor lestaurtinib inhibited PKN1 action and preferentially affected androgen regulation of SRF over direct AR target genes. In a CR-CaP patient-derived xenograft, expression of SRF target genes was maintained while AR target gene expression declined and proliferative gene expression increased. PKN1 inhibition decreased viability of CaP cells before and after ADT. In patient-derived CaP explants, lestaurtinib increased AR target gene expression but did not significantly alter SRF target gene or proliferative gene expression. These results provide proof-of-principle for selective forms of ADT that preferentially target different fractions of AR's transcriptional output to inhibit CaP growth.

Management of recurrent prostate cancer after radiotherapy: long-term results from CALGB 9687 (Alliance), a prospective multi-institutional salvage prostatectomy series

BACKGROUND

To evaluate efficacy and morbidity prospectively in a contemporary multi-institutional salvage radical prostatectomy (SRP) series.

METHODS

Forty-one men were enrolled between 1997 and 2006, who suffered biopsy-proven recurrent prostate cancer (CaP) after receiving ≥ 60c Gy radiation as primary treatment for cT_1-2N_XM₀ disease. Surgical morbidity, quality of life, biochemical progression-free survival (BPFS) and overall survival (OS) were evaluated.

RESULTS

Twenty-four men had undergone external beam radiotherapy, 11 brachytherapy, and six both. Median time between radiation and SRP was 64 months. Median age at SRP was 64 years. Pathologic staging revealed 44% pT2, 54% pT3, and 3% pT4. Surgical margins were positive in 17 and 88% were pN0. Twenty-two percent required intraoperative blood transfusion. Three rectal and one obturator nerve injuries occurred. Seventeen of 38 evaluable patients (45%) had urinary incontinence ( ≥ 3 pads/day) prior to SRP; 88% reported urinary incontinence at 6 months, 85% at 12 months, 63% at 24 months after SRP. Furthermore, 37% of men reported impotence prior to SRP; 78% reported impotence at 6 months, 82% at 12 months, and 44% at 24 months after SRP. The 2-, 5- and 10-year BPFS rates were 51, 39, and 33% respectively; the 2-, 5- and 10-year OS rates were 100, 89, and 52%, respectively, at median follow-up 91 months.

CONCLUSIONS

Modern surgical techniques continue to be associated with significant peri-operative complication rates. Nevertheless, SRP may benefit carefully selected patients through durable oncologic control.

Potential impact of combined inhibition of 3α-oxidoreductases and 5α-reductases on prostate cancer

Prostate cancer (PCa) growth and progression rely on the interaction between the androgen receptor (AR) and the testicular ligands, testosterone and dihydrotestosterone (DHT). Almost all men with advanced PCa receive androgen deprivation therapy (ADT). ADT lowers circulating testosterone levels, which impairs AR activation and leads to PCa regression. However, ADT is palliative and PCa recurs as castration-recurrent/resistant PCa (CRPC). One mechanism for PCa recurrence relies on intratumoral synthesis of DHT, which can be synthesized using the frontdoor or primary or secondary backdoor pathway. Androgen metabolism inhibitors, such as those targeting 5α-reductase, aldo-keto-reductase family member 3 (AKR1C3), or cytochrome P450 17A1 (CYP17A1) have either failed or produced only modest clinical outcomes. The goal of this review is to describe the therapeutic potential of combined inhibition of 5α-reductase and 3α-oxidoreductase enzymes that facilitate the terminal steps of the frontdoor and primary and secondary backdoor pathways for DHT synthesis. Inhibition of the terminal steps of the androgen metabolism pathways may be a way to overcome the shortcomings of existing androgen metabolism inhibitors and thereby delay PCa recurrence during ADT or enhance the response of CRPC to androgen axis manipulation.

Linking prostate cancer cell AR heterogeneity to distinct castration and enzalutamide responses

Expression of androgen receptor (AR) in prostate cancer (PCa) is heterogeneous but the functional significance of AR heterogeneity remains unclear. Screening ~200 castration-resistant PCa (CRPC) cores and whole-mount sections (from 89 patients) reveals 3 AR expression patterns: nuclear (nuc-AR), mixed nuclear/cytoplasmic (nuc/cyto-AR), and low/no expression (AR-/lo). Xenograft modeling demonstrates that AR+ CRPC is enzalutamide-sensitive but AR-/lo CRPC is resistant. Genome editing-derived AR+ and AR-knockout LNCaP cell clones exhibit distinct biological and tumorigenic properties and contrasting responses to enzalutamide. RNA-Seq and biochemical analyses, coupled with experimental combinatorial therapy, identify BCL-2 as a critical therapeutic target and provide proof-of-concept therapeutic regimens for both AR+/hi and AR-/lo CRPC. Our study links AR expression heterogeneity to distinct castration/enzalutamide responses and has important implications in understanding the cellular basis of prostate tumor responses to AR-targeting therapies and in facilitating development of novel therapeutics to target AR-/lo PCa cells/clones.

Dietary patterns based on the Mediterranean diet and DASH diet are inversely associated with high aggressive prostate cancer in PCaP

BACKGROUND

Several foods and nutrients have been linked to the development of prostate cancer, but the association between healthy dietary patterns and prostate cancer aggressiveness is less studied. The aim of this study was to evaluate the relationship between the Mediterranean diet (MED) and Dietary Approaches to Stop Hypertension (DASH) diet scores and prostate cancer aggressiveness by race.

METHODS

Data from the population-based, case-only North Carolina-Louisiana Prostate Cancer Project (PCaP) were used to examine the association between diet quality, measured by MED and DASH scores, and prostate cancer aggressiveness in 1899 African American (AA) and European American (EA) research subjects. Dietary intake was assessed using a modified National Cancer Institute Diet History Questionnaire. Logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for high versus low-intermediate aggressive prostate cancer.

RESULTS

Higher MED scores were inversely associated with high aggressive prostate cancer overall (OR: 0.66; 95% CI: 0.46, 0.95 for high versus low scores); results were similar for AA and EA men. A weaker inverse association between DASH scores and prostate cancer aggressiveness was found (OR: 0.76; 95% CI: 0.55, 1.06).

CONCLUSIONS

Higher diet quality, as represented by a Mediterranean-style diet or DASH diet, may reduce the odds of high aggressive prostate cancer.

Proteomic Analysis of Charcoal-Stripped Fetal Bovine Serum Reveals Changes in the Insulin-like Growth Factor Signaling Pathway

Charcoal-stripped fetal bovine serum (CS-FBS) is commonly used to study androgen responsiveness and androgen metabolism in cultured prostate cancer (CaP) cells. Switching CaP cells from FBS to CS-FBS may reduce the activity of androgen receptor (AR), inhibit cell proliferation, or modulate intracellular androgen metabolism. The removal of proteins by charcoal stripping may cause changes in biological functions and has not yet been investigated. Here we profiled proteins in FBS and CS-FBS using an ion-current-based quantitative platform consisting of reproducible surfactant-aided precipitation/on-pellet digestion, long-column nanoliquid chromatography separation, and ion-current-based analysis. A total of 143 proteins were identified in FBS, among which 14 proteins including insulin-like growth factor 2 (IGF-2) and IGF binding protein (IGFBP)-2 and -6 were reduced in CS-FBS. IGF-1 receptor (IGF1R) and insulin receptor were sensitized to IGFs in CS-FBS. IGF-1 and IGF-2 stimulation fully compensated for the loss of AR activity to maintain cell growth in CS-FBS. Endogenous production of IGF and IGFBPs was verified in CaP cells and clinical CaP specimens. This study provided the most comprehensive protein profiles of FBS and CS-FBS and offered an opportunity to identify new protein regulators and signaling pathways that regulate AR activity, androgen metabolism, and proliferation of CaP cells.

Statin use, high cholesterol and prostate cancer progression; results from HCaP-NC

BACKGROUND

Statin use is associated with lower advanced prostate cancer risk and reduced prostate cancer-specific mortality, but prior studies were conducted mainly in white men. We examined the effect of statin use on risk of prostate cancer progression in a population-based, minority-enriched cohort.

METHODS

We used data from prostate cancer cases (45% African American) diagnosed between 2004 and 2007 who participated in the Health Care Access and Prostate Cancer Treatment in North Carolina cohort (HCaP-NC). We abstracted statin use at diagnosis. Men reported if they had ever been diagnosed with high cholesterol. Multivariable Cox proportional hazards analysis was used to examine associations between statin use and risk of prostate cancer progression (biochemical recurrence or secondary treatment), overall and by race. In secondary analysis, we examined the association between high cholesterol and risk of progression, overall, and by statin use.

RESULTS

Of 669 men, 244 (36%) were statin users at diagnosis. During 3.8 years median follow-up, 138 men experienced prostate cancer progression. There was no association between statin use and risk of progression, either overall (HR 1.03; 95%CI 0.72-1.46) or stratified by race. High cholesterol was inversely associated with risk of progression, particularly among statin users (HR 0.43; 95%CI 0.20-0.94; p-interaction = 0.22) and in men with higher perceived access to care (HR 0.57; 95%CI 0.36-0.90; p-interaction = 0.03). Study limitations included a relatively small sample size, short follow-up, and lack of data regarding post diagnosis statin use.

CONCLUSIONS

Statin use at diagnosis was not associated with prostate cancer progression in the population-based, minority-enriched HCaP-NC. Greater healthcare engagement, including actively controlling serum cholesterol, may be linked to better prostate cancer-specific outcomes.

Mathematical modeling of intracrine androgen metabolism in prostate cancer: Methodological aspects

BACKGROUND

Progression of castration-recurrent/resistant prostate cancer (CRPC) relies in part on dihydrotestosterone derived from intratumoral androgen metabolism. Mathematical modeling provides a valuable tool for studies of androgen metabolism in CRPC. This modeling approach integrates existing knowledge about complex biologic systems and provides a means of interrogating the effects of various interventions. We sought to model a single reaction in the androgen biosynthesis network, namely the oxidation of androsterone (AND) to androstanedione (5α-dione) by four 3α-oxidoreductase enzymes, as an initial effort to establish the feasibility of our modeling approach.

METHODS

Models were constructed for two cell culture systems, a non-prostate cancer cell line (CV-1) and a prostate cancer cell line (LAPC-4), using the SimBiology app (version 5.3) in MATLAB (version 8.6). The models included components for substrate (AND), product (5α-dione), each of the four enzymes, and each of the four enzyme-substrate complexes. Each enzymatic reaction consisted of a reversible enzyme-substrate binding step and an irreversible catalysis step. Rates of change for each component were described using ordinary differential equations.

RESULTS

Mathematical models were developed with model parameter values derived from literature sources or from existing experimental data, which included gene expression measurements and substrate and product concentrations determined using liquid chromatography-tandem mass spectrometry. The models for both cell lines adequately described substrate and product concentrations observed after 12 h treatment with AND.

CONCLUSIONS

This modeling approach represents an adaptable, extensible and mechanistic framework that reflects androgen metabolism. The models can be expanded systematically to describe the complex androgen metabolic pathways important for study of novel therapies for CRPC.

Modelling attrition and nonparticipation in a longitudinal study of prostate cancer

Background

Attrition occurs when a participant fails to respond to one or more study waves. The accumulation of attrition over several waves can lower the sample size and power and create a final sample that could differ in characteristics than those who drop out. The main reason to conduct a longitudinal study is to analyze repeated measures; research subjects who drop out cannot be replaced easily. Our group recently investigated factors affecting nonparticipation (refusal) in the first wave of a population-based study of prostate cancer. In this study we assess factors affecting attrition in the second wave of the same study. We compare factors affecting nonparticipation in the second wave to the ones affecting nonparticipation in the first wave.

Methods

Information available on participants in the first wave was used to model attrition. Different sources of attrition were investigated separately. The overall and race-stratified factors affecting attrition were assessed. Kaplan-Meier survival curve estimates were calculated to assess the impact of follow-up time on participation.

Results

High cancer aggressiveness was the main predictor of attrition due to death or frailty. Higher Charlson Comorbidity Index increased the odds of attrition due to death or frailty only in African Americans (AAs). Young age at diagnosis for AAs and low income for European Americans (EAs) were predictors for attrition due to lost to follow-up. High cancer aggressiveness for AAs, low income for EAs, and lower patient provider communication scores for EAs were predictors for attrition due to refusal. These predictors of nonparticipation were not the same as those in wave 1. For short follow-up time, the participation probability of EAs was higher than that of AAs.

Conclusions

Predictors of attrition can vary depending on the attrition source. Examining overall attrition (combining all sources of attrition under one category) instead of distinguishing among its different sources should be avoided. The factors affecting attrition in one wave can be different in a later wave and should be studied separately.

Developing antineoplastic agents that target peroxisomal enzymes: cytisine-linked isoflavonoids as inhibitors of hydroxysteroid 17-beta-dehydrogenase-4 (HSD17B4)

Cytisine-linked isoflavonoids (CLIFs) inhibited PC-3 prostate and LS174T colon cancer cell proliferation by inhibiting a peroxisomal bifunctional enzyme. A pull-down assay using a biologically active, biotin-modified CLIF identified the target of these agents as the bifunctional peroxisomal enzyme, hydroxysteroid 17β-dehydrogenase-4 (HSD17B4). Additional studies with truncated versions of HSD17B4 established that CLIFs specifically bind the C-terminus of HSD17B4 and selectively inhibited the enoyl CoA hydratase but not the d-3-hydroxyacyl CoA dehydrogenase activity. HSD17B4 was overexpressed in prostate and colon cancer tissues, knocking down HSD17B4 inhibited cancer cell proliferation, suggesting that HSD17B4 is a potential biomarker and drug target and that CLIFs are potential probes or therapeutic agents for these cancers.

A brief history of intracrine androgen metabolism by castration-recurrent prostate cancer

This mini-review describes the evolution of the concept of intracrine androgen metabolism by prostate cancer during androgen deprivation therapy. Persistence of androgen receptor protein in the face of castrate circulating levels of testosterone could not be explained fully by hypersensitization or mutation of the androgen receptor. The hypothesis that castration-recurrent prostate cancer produced its own testosterone was proven using radioimmunoassay and mass spectrometry methods adopted for use in prostate tissue. Intracrine synthesis of testicular androgens led to FDA approval of abiraterone, an inhibitor of androgen metabolism. Further understanding of intracrine androgen metabolism may allow the development of more targeted agents that perform better and do not require co-administration of prednisone that may extend survival and diminish side effects from treatment of advanced prostate cancer.

Inhibition of dihydrotestosterone synthesis in prostate cancer by combined frontdoor and backdoor pathway blockade

Androgen deprivation therapy (ADT) is palliative and prostate cancer (CaP) recurs as lethal castration-recurrent/resistant CaP (CRPC). One mechanism that provides CaP resistance to ADT is primary backdoor androgen metabolism, which uses up to four 3α-oxidoreductases to convert 5α-androstane-3α,17β-diol (DIOL) to dihydrotestosterone (DHT). The goal was to determine whether inhibition of 3α-oxidoreductase activity decreased conversion of DIOL to DHT. Protein sequence analysis showed that the four 3α-oxidoreductases have identical catalytic amino acid residues. Mass spectrometry data showed combined treatment using catalytically inactive 3α-oxidoreductase mutants and the 5α-reductase inhibitor, dutasteride, decreased DHT levels in CaP cells better than dutasteride alone. Combined blockade of frontdoor and backdoor pathways of DHT synthesis provides a therapeutic strategy to inhibit CRPC development and growth.

Serum-free complete medium, an alternative medium to mimic androgen deprivation in human prostate cancer cell line models

BACKGROUND

Almost all men who present with advanced prostate cancer (CaP) and some men who fail therapy for clinically localized CaP are treated with androgen deprivation therapy (ADT). CaP cell lines are used to identify and characterize new agents for ADT or investigate mechanisms of ADT resistance. CaP cell lines are maintained in culture medium that contains fetal bovine serum, which contains testosterone (T). Androgen deprivation experiments are performed using media supplemented with androgen-free serum, such as charcoal stripped fetal bovine serum (CS-FBS). However, CS-FBS composition varies from batch-to-batch and variations may impact experimental reproducibility. Serum free media (SFM) may provide a better defined alternative to media supplemented with CS-FBS (CSM).

METHODS

Cell growth of six human CaP cell lines was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Androgen levels were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

MTT assays showed 5 of 6 CaP cell lines grew after 6 days of culture in androgen- deprived SFM or CSM. LNCaP and VCaP growth was stimulated when cells were cultured in SFM or CSM supplemented with T. LNCaP, C4-2, LAPC-4, and VCaP cell growth was inhibited when cultured in SFM or CSM with T and bicalutamide. LC-MS/MS data showed LAPC-4 cells produced similar DHT levels when cultured in T-supplemented SFM or CSM. Dutasteride impaired T to DHT metabolism in LAPC-4.

CONCLUSIONS

Media composition contributed to growth differences observed between CaP cells cultured in SFM or CSM. However, the differences in media composition did not impair CaP cell response to T-stimulated growth, bicalutamide growth inhibition, metabolism of T, or dutasteride efficiency. SFM can be used as a better defined alternative to CSM for androgen deprivation experiments.

Characterization of Prostate Cancer in a Functional Eunuch

BACKGROUND

Eunuchs rarely, if ever, develop prostate cancer (CaP). This article reports on a 62-year-old functional eunuch from prepubertal mumps orchitis who developed clinically localized CaP.

METHODS

Serum and CaP and benign prostate tissue androgen levels were measured using a validated liquid chromatography-tandem mass spectrometry assay. The assay measures testosterone; dihydrotestosterone (DHT); the adrenal androgens, androstenedione and dehydroepiandrosterone; and the androgen metabolites, androsterone and androstanedione. Gene and protein expression levels of androgen metabolism enzymes, and androgen receptor and androgen-regulated genes were measured using quantitative reverse-transcription polymerase chain reaction and immunohistochemistry, respectively.

RESULTS

Intracrine androgen metabolism produced tissue DHT when serum and tissue testosterone levels were castrate and undetectable, respectively. Androgen receptor, androgen-regulated, and androgen metabolism enzyme genes were expressed but at lower levels in CaP than benign tissues.

CONCLUSIONS

DHT was synthesized using the primary backdoor androgen metabolism pathway and not using androstenedione or dehydroepiandrosterone via the frontdoor or secondary backdoor pathways.

Validation of the Kattan Nomogram for Prostate Cancer Recurrence After Radical Prostatectomy

BACKGROUND

The Kattan postoperative radical prostatectomy (RP) nomogram is used to predict biochemical recurrence-free progression (BCRFP) after RP. However, external validation among contemporary patients using modern outcome definitions is limited.

METHODS

A total of 1,931 patients who underwent RP at Roswell Park Cancer Institute (RPCI) between 1993 and 2014 (median follow-up, 47 months; range, 0-244 months) were assessed for NCCN-defined biochemical failure (BF) and RPCI-defined treatment failure (TF). Actual rates of biochemical failure-free survival (BFS; defined as 1 - BF) and treatment failure-free survival (TFS; defined as 1 - TF) were compared with Kattan BCRFP nomogram predictions.

RESULTS

The Kattan BCRFP nomogram predictions at 5 and 10 years were predictive of BFS (area under the receiver operating characteristic curve [AUC], 0.772) and TFS (AUC, 0.774). The Kattan BCRFP nomogram tended to underestimate BFS and TFS compared with actual outcomes. The Kattan 5-year BCRFP predictions consistently overestimated actual 5-year BFS outcomes among subgroups of high- and intermediate-risk patients with at least 5-year outcomes.

CONCLUSIONS

The Kattan BCRFP nomogram is a robust predictor of NCCN-defined BF in a large sample of patients with RP with substantial follow-up and modern, standardized failure definitions.

Blinded review of archival radical prostatectomy specimens supports that contemporary Gleason score 6 prostate cancer lacks metastatic potential

BACKGROUND

Retrospective identification of Gleason pattern 4 in metastatic Gleason score 3 + 3 = 6 (GS6) radical prostatectomy (RP) specimens has suggested true GS6 prostate cancer (CaP) lacks metastatic potential. However, pathologist awareness of study design and metastasis outcomes at the time of RP review might have introduced upgrading bias. We used pathologist-blinded methodology for unbiased characterization of metastasis rates for contemporarily defined pathologic GS6 (pGS6) CaP.

METHODS

An institutional RP database was queried to identify pGS6 patients with metastasis or concern for micrometastasis based on: 1) biochemical failure (BF) despite negative surgical margins or 2) incomplete biochemical response to salvage/adjuvant radiation. RP specimens were regraded independently by two genitourinary pathologists blinded to study aims or clinical outcomes. Additional blinding was performed by random inclusion of pGS6 control specimens from BF-free patients. Only upgrading identified independently by both pathologists was considered.

RESULTS

Among 451 pGS6 patients identified, none had synchronous lymph node metastases and 43/451 (10%) suffered BF. Two patients (0.4%) developed metachronous metastasis during a 110-month median follow-up for BF patients. Both metastatic cases had Gleason pattern 4 on blinded RP review, as did 88% of cases with concern for micrometastasis versus 38% of control cases (P = 0.02). All BF patients (29/29) undergoing postoperative radiation had a complete biochemical response or Gleason pattern 4 on blinded RP review.

CONCLUSIONS

Unbiased pathologist review of archival RP specimens supports absent metastatic potential for contemporarily defined GS6 CaP. Reduced postoperative monitoring is appropriate for pGS6, but may require pathology review to confirm absent Gleason pattern 4.

Lipid degradation promotes prostate cancer cell survival

Prostate cancer is the most common male cancer and androgen receptor (AR) is the major driver of the disease. Here we show that Enoyl-CoA delta isomerase 2 (ECI2) is a novel AR-target that promotes prostate cancer cell survival. Increased ECI2 expression predicts mortality in prostate cancer patients (p = 0.0086). ECI2 encodes for an enzyme involved in lipid metabolism, and we use multiple metabolite profiling platforms and RNA-seq to show that inhibition of ECI2 expression leads to decreased glucose utilization, accumulation of fatty acids and down-regulation of cell cycle related genes. In normal cells, decrease in fatty acid degradation is compensated by increased consumption of glucose, and here we demonstrate that prostate cancer cells are not able to respond to decreased fatty acid degradation. Instead, prostate cancer cells activate incomplete autophagy, which is followed by activation of the cell death response. Finally, we identified a clinically approved compound, perhexiline, which inhibits fatty acid degradation, and replicates the major findings for ECI2 knockdown. This work shows that prostate cancer cells require lipid degradation for survival and identifies a small molecule inhibitor with therapeutic potential.

The Association of Diabetes and Obesity With Prostate Cancer Progression: HCaP-NC

BACKGROUND

The role of race in modifying the association among diabetes, obesity, and prostate cancer (CaP) progression is not well studied. We evaluated diabetes and obesity in association with time to CaP progression in White Americans (Whites) and Black Americans (Blacks).

METHODS

Our study sample consisted of 363 White and 284 Black research participants from the Health Care Access and CaP Treatment in North Carolina (HCaP-NC) cohort. The association between self-reported diabetes or obesity and CaP progression (mean follow-up time approximately 5 years) was assessed using Cox proportional hazards modeling, with adjustment for potential confounders. Stratum-specific hazard ratio (HR) estimates for Whites and Blacks were evaluated.

RESULTS

Self-reported diabetes was not associated with CaP progression in the cohort as a whole (HR: 0.86, 95%CI: 0.54, 1.35), or among racially defined groups (Whites, HR: 1.03, 95%CI: 0.50, 2.13 or Blacks, HR: 0.77, 95%CI: 0.43, 1.39). Obesity was positively associated with CaP progression among Whites, in models including (HR: 1.79, 95%CI: 1.08, 2.97), and excluding (HR: 1.80, 95%CI: 1.09, 2.96) diabetes as a covariate. No association was observed between obesity and CaP progression in Blacks or the cohort as whole.

CONCLUSIONS

Self-reported diabetes was not associated with CaP progression In HCaP-NC. Obesity was associated with CaP progression only among White research participants. Prostate 77:878-887, 2017. © 2017 Wiley Periodicals, Inc.

Up-Regulation of Follistatin-Like 1 By the Androgen Receptor and Melanoma Antigen-A11 in Prostate Cancer

BACKGROUND

High affinity androgen binding to the androgen receptor (AR) activates genes required for male sex differentiation and promotes the development and progression of prostate cancer. Human AR transcriptional activity involves interactions with coregulatory proteins that include primate-specific melanoma antigen-A11 (MAGE-A11), a coactivator that increases AR transcriptional activity during prostate cancer progression to castration-resistant/recurrent prostate cancer (CRPC).

METHODS

Microarray analysis and quantitative RT-PCR were performed to identify androgen-regulated MAGE-A11-dependent genes in LAPC-4 prostate cancer cells after lentivirus shRNA knockdown of MAGE-A11. Chromatin immunoprecipitation was used to assess androgen-dependent AR recruitment, and immunocytochemistry to localize an androgen-dependent protein in prostate cancer cells and tissue and in the CWR22 human prostate cancer xenograft.

RESULTS

Microarray analysis of androgen-treated LAPC-4 prostate cancer cells indicated follistatin-like 1 (FSTL1) is up-regulated by MAGE-A11. Androgen-dependent up-regulation of FSTL1 was inhibited in LAPC-4 cells by lentivirus shRNA knockdown of AR or MAGE-A11. Chromatin immunoprecipitation demonstrated AR recruitment to intron 10 of the FSTL1 gene that contains a classical consensus androgen response element. Increased levels of FSTL1 protein in LAPC-4 cells correlated with higher levels of MAGE-A11 relative to other prostate cancer cells. FSTL1 mRNA levels increased in CRPC and castration-recurrent CWR22 xenografts in association with predominantly nuclear FSTL1. Increased nuclear localization of FSTL1 in prostate cancer was suggested by predominantly cytoplasmic FSTL1 in benign prostate epithelial cells and predominantly nuclear FSTL1 in epithelial cells in CRPC tissue and the castration-recurrent CWR22 xenograft. AR expression studies showed nuclear colocalization of AR and endogenous FSTL1 in response to androgen.

CONCLUSION

AR and MAGE-A11 cooperate in the up-regulation of FSTL1 to promote growth and progression of CRPC. Prostate 77:505-516, 2017. © 2016 Wiley Periodicals, Inc.

Development, validation and clinical application of Pelvic Lymphadenectomy Assessment and Completion Evaluation: intraoperative assessment of lymph node dissection after robot-assisted radical cystectomy for bladder cancer

OBJECTIVES

To develop a scoring tool, Pelvic Lymphadenectomy Appropriateness and Completion Evaluation (PLACE), to assess the intraoperative completeness and appropriateness of pelvic lymph node dissection (PLND) following robot-assisted radical cystectomy (RARC).

PATIENTS, SUBJECTS AND METHODS

A panel of 11 open and robotic surgeons developed the content and structure of PLACE. The PLND template was divided into three zones. In all, 21 de-identified videos of bilateral robot-assisted PLNDs were assessed by the 11 experts using PLACE to determine inter-rater reliability. Lymph node (LN) clearance was defined as the proportion of cleared LNs from all PLACE zones. We investigated the correlation between LN clearance and LN count. Then, we compared the LN count of 18 prospective PLNDs using PLACE with our retrospective series performed using the extended template (No PLACE).

RESULTS

A significant reliability was achieved for all PLACE zones among the 11 raters for the 21 bilateral PLND videos. The median (interquartile range) for LN clearance was 468 (431-545). There was a significant positive correlation between LN clearance and LN count (R² = 0.70, P < 0.01). The PLACE group yielded similar LN counts when compared to the No PLACE group.

CONCLUSIONS

Pelvic Lymphadenectomy Appropriateness and Completion Evaluation is a structured intraoperative scoring system that can be used intraoperatively to measure and quantify PLND for quality control and to facilitate training during RARC.

A four gene signature predictive of recurrent prostate cancer

Prostate cancer is the most common form of non-dermatological cancer among US men, with an increasing incidence due to the aging population. Patients diagnosed with clinically localized disease identified as intermediate or high-risk are often treated by radical prostatectomy. Approximately 33% of these patients will suffer recurrence after surgery. Identifying patients likely to experience recurrence after radical prostatectomy would lead to improved clinical outcomes, as these patients could receive adjuvant radiotherapy. Here, we report a new tool for prediction of prostate cancer recurrence based on the expression pattern of a small set of cooperation response genes (CRGs). CRGs are a group of genes downstream of cooperating oncogenic mutations previously identified in a colon cancer model that are critical to the cancer phenotype. We show that systemic dysregulation of CRGs is also found in prostate cancer, including a 4-gene signature (HBEGF, HOXC13, IGFBP2, and SATB1) capable of differentiating recurrent from non-recurrent prostate cancer. To develop a suitable diagnostic tool to predict disease outcomes in individual patients, multiple algorithms and data handling strategies were evaluated on a training set using leave-one-out cross-validation (LOOCV). The best-performing algorithm, when used in combination with a predictive nomogram based on clinical staging, predicted recurrent and non-recurrent disease outcomes in a blinded validation set with 83% accuracy, outperforming previous methods. Disease-free survival times between the cohort of prostate cancers predicted to recur and predicted not to recur differed significantly (p = 1.38x10-6). Therefore, this test allows us to accurately identify prostate cancer patients likely to experience future recurrent disease immediately following removal of the primary tumor.