Clinical Progression Of Prostate Cancer Research Articles

Prognostic Significance of the Cribriform Pattern in Prostate Cancer: Clinical Outcomes and Genomic Alterations.

Given the diverse clinical progression of prostate cancer (PC) and the evolving significance of histopathological factors in its management, this study aimed to explore the impact of cribriform pattern 4 (CP4) on clinical outcomes in PC patients and examine its molecular characteristics. This retrospective study analyzed data from The Cancer Genome Atlas (TCGA) database and included PC patients who underwent radical prostatectomy (RP) and had pathology slides available for the assessment of CP4. A multivariable competing risk regression analysis was used to assess the association between CP4 and progression-free survival (PFS) while adjusting for established PC prognostic factors. The frequency of genomic alterations was compared between patients with and without CP4 using the Fisher's exact test. Among the 394 patients analyzed, 129 (32.74%) had CP4. After a median follow-up of 40.50 months (IQR: 23.90, 65.60), the presence of CP4 was significantly associated with lower PFS (AHR, 1.84; 95% CI, 1.08 to 3.114; p = 0.023) after adjusting for covariates. Seven hub genes-KRT13, KRT5, KRT15, COL17A1, KRT14, KRT16, and TP63-had significantly lower mRNA expression levels in patients with CP4 compared to those without. PC patients with CP4 have distinct genomic alterations and are at a high risk of disease progression following RP. Therefore, these patients may benefit from additional post-RP treatments and should be the subject of a prospective randomized clinical trial.

PD56-01 PROSTATE SPECIFIC ANTIGEN KINETICS PREDICT INCIDENTAL PROSTATE CANCER PROGRESSION FOLLOWING HOLMIUM LASER ENUCLEATION OF THE PROSTATE

You have accessJournal of UrologyBenign Prostatic Hyperplasia: Surgical Therapy & New Technology III (PD56)1 Apr 2020PD56-01 PROSTATE SPECIFIC ANTIGEN KINETICS PREDICT INCIDENTAL PROSTATE CANCER PROGRESSION FOLLOWING HOLMIUM LASER ENUCLEATION OF THE PROSTATE Kyle Rose*, Kassem Faraj, Anojan Navaratnam, Marlene Girardo, Amihay Nevo Pima, Karan Arora, Scott Cheney, and Mitchell Humphreys Kyle Rose*Kyle Rose* More articles by this author , Kassem FarajKassem Faraj More articles by this author , Anojan NavaratnamAnojan Navaratnam More articles by this author , Marlene GirardoMarlene Girardo More articles by this author , Amihay Nevo PimaAmihay Nevo Pima More articles by this author , Karan AroraKaran Arora More articles by this author , Scott CheneyScott Cheney More articles by this author , and Mitchell HumphreysMitchell Humphreys More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000966.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Holmium laser enucleation of the prostate (HoLEP) allows for the definitive management of benign prostatic hyperplasia and histopathologic analysis. The complete adenomectomy of HoLEP allows for the diagnosis of incidental prostate cancer (PCA). Outcomes data regarding the clinical progression of PCA following HoLEP is lacking. The objective of this study is to describe the clinical course of patients diagnosed with PCA after HoLEP, and identify predictors for clinical progression in this population. METHODS: HoLEP cases performed at our institution by a single surgeon from 2008-2018 were reviewed and monitored for incidentally diagnosed PCA. Clinical progression of PCA was defined as the need for additional therapeutic intervention or the development of metastatic disease. Univariate analysis was conducted using Chi-squared and T-tests when appropriate. Kaplan Meier estimates were used to evaluate survival. RESULTS: Of 1,288 HoLEP patients, 133 patients were diagnosed with incidental PCA. Seventeen (12.7%) patients met criteria for clinical progression at a median of 20 months postoperatively. On univariate logistic regression, predictors of clinical progression included preoperative prostate specific antigen density (PSAD) >0.15 (OR 3.4, 95% CI 1.7-6.6, p<0.01), T1b vs. T1a (OR 2.9, 95% CI 1.6-5.2), first postoperative PSA >1 (OR 2.1, 95% CI 1.9-2.3, p<0.01), PSADT <36 months (OR 9.2, 95% CI 1.15-74.8, P=0.01) and PSA velocity >0.75 (OR 14.6, 95% CI 3.5-60.7, p<0.01). When predicting clinical progression, the sensitivity of PSADT <36 months was 94%, the negative predictive values for first postop PSA >1 was 94%, PSA velocity >0.75 ng/mL/year was 95%, and PSA DT <36 months was 97%. Progression-free survival was 101.9 months in T1a vs. 61.5 months in T1b disease (p<0.01). CONCLUSIONS: PSA kinetics are informative in predicting clinical progression following HoLEP. These parameters can be used to risk stratify patients diagnosed with incidental PCa after HoLEP. Source of Funding: none © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e1188-e1188 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kyle Rose* More articles by this author Kassem Faraj More articles by this author Anojan Navaratnam More articles by this author Marlene Girardo More articles by this author Amihay Nevo Pima More articles by this author Karan Arora More articles by this author Scott Cheney More articles by this author Mitchell Humphreys More articles by this author Expand All Advertisement PDF downloadLoading ...

Abstract 4285: p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells

Abstract Purpose and Background: Prostate cancer (PCa) is the second leading cause of cancer-related death in United States men. Androgen deprivation therapy is the standard-of-care treatment for metastatic PCa; most patients eventually relapse and develop castration-resistant (CR) tumors that currently have no effective treatment. Thus, a useful cell model for analysis of the molecular mechanism of PCa progression is required for developing targeted therapies for CR PCa. In this study, we established a PCa cell progressive model in three independent cell lines, of which androgen-independent (AI) cells were derived from respective androgen-sensitive (AS) cells, recapitulating clinical PCa progression. Experimental Methods: AS and AI human prostate adenocarcinoma cell lines LNCaP, MDA PCa2b and VCaP were utilized in this study to demonstrate the molecular and signaling alterations seen in CR PCa. Stable p66Shc cDNA transfected subclones were established from LNCaP-AS cells. The tumorigenicity of AS and AI cells as well as AS PCa cells treated with H2O2 and NAC were evaluated via trypan blue exclusion, transwell migration, clonogenic assays and xenograft mouse models. The signaling profiles including phosphoprotein microarray and immunoblotting were conducted. Results: AI PCa cells have enhanced tumorigenicity, recapitulating the clinical CR phenotype, including AR expression, proliferation and tumorigenicity under androgen-deprived conditions. Further, AI cells exhibit increased ROS levels as well as enhanced signaling of proliferation and survival pathways. We further identified oxidase p66Shc as one of the potential sources of the ROS-mediated phenotypic and cell signaling alterations in AI PCa cells. LNCaP-AI cells and p66Shc subclones have a greater oxidative environment compared to LNCaP-AS cells. Increased ROS via H2O2 enhanced AS cell growth and migration, which was counteracted by antioxidant NAC. Treatment of LNCaP-AS cells with H2O2 resulted in a similar signaling profile to that of LNCaP-AI or p66Shc subclone cells. Further, the ROS-driven alterations of p66Shc subclone cell signaling can be mitigated via p66Shc knockdown or inactive p66Shc mutant. Moreover, LNCaP-AI cells and p66Shc subclones, but not LNCaP-AS cells, develop xenograft tumors with metastatic nodules. Molecular profiling showed that alterations of signaling in LNCaP-AI cells and p66Shc subclones attributed to p66Shc/ROS. Conclusions: We report the establishment of a PCa cell progression model in three commonly used PCa cell lines that replicates clinical PCa progression from the AS to the AI/CR phenotype. Altogether, the data shows ROS produced by p66Shc promotes PCa tumorigenicity and progression to the CR phenotype. Further characterization of the PCa progressive model will aid in the understanding of advanced PCa progression to help in treatment of this lethal disease. Citation Format: Dannah Miller, Matthew Ingersoll, Arpita Chatterjee, Rebecca Oberley-Deegan, Ming-Fong Lin. p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4285.

Methods to Study Angiogenesis in a Mouse Model of Prostate Cancer.

Angiogenesis is one important hallmark of cancer progression which explains the relevance of developing methods to efficiently analyze the neo-angiogenic process. In this report we make use of the transgenic adenocarcinoma of the murine prostate (TRAMP) model, considered a good model for studying clinical prostate cancer progression, to describe in detail the methods used to study angiogenesis in this type of solid tumor development. In this report we provide step-by-step procedures on the basis of previous work in our laboratory for: the mouse urogenital sinus (UGS) collection; microdissection of the prostate; preparation of the prostatic samples for immunofluorescence (to analyze vascular density, morphology, maturation, functionality, hypoxia, and others); preparation of prostatic samples to histopathological analysis and/or immunohistochemistry; and endothelial and vascular mural cell sorting and isolation by fluorescent associated cell sorting (FACS) to further analysis (mRNA, protein, or other) or to maintain in culture.

Androgen-independent LNCaP cells are a subline of LNCaP cells with a more aggressive phenotype and androgen suppresses their growth by inducing cell cycle arrest at the G1phase.

Androgen deprivation therapy (ADT, surgical or chemical castration) is the mainstay treatment for metastatic prostate cancer (PCa); however, patients ineluctably relapse despite extremely low androgen levels. This evolution of PCa indicates its lethal progression. In this study, to mimic the traits of clinical PCa progression in vitro, we investigated the alterations in the cell biological characteristics in androgen-independent LNCaP cells (LNCaP-AI cells) compared with LNCaP cells. We also examined the effects of androgen on LNCaP and LNCaP-AI cell proliferation, androgen receptor (AR) expression and prostate-specific antigen (PSA) secretion. Furthermore, AR was silenced in the LNCaP and LNCaP-AI cells to detect the roles that AR plays in cell growth, apoptosis and PSA secretion. We found that prolonged androgen ablation increased the LNCaP-AI cell growth rate and cell invasiveness, and induced epithelial-mesenchymal transition in the LNCaP-AI cells. Moreover, despite the fact that the LNCaP and LNCaP-AI cells expressed equal amounts of AR protein, androgen induced a greater secretion of PSA in the LNCaP-AI cells than in the LNCaP cells. The proliferation of the LNCaP-AI cells was not dependent on, but was suppressed by androgen, which led to arrest at the G1 phase. Conversely, androgen significantly increased LNCaP cell proliferation by promoting the G1-S transition. Moreover, the silencing of AR suppressed LNCaP and LNCaP-AI cell growth by inducing cell cycle arrest at the G1 phase rather than promoting apoptosis, and reduced PSA secretion. On the whole, our data suggest that LNCaP-AI cells have a more more aggressive phenotype compared with the LNCaP cells; AR remains a critical factor in the LNCaP-AI cells, and androgen suppresses LNCaP-AI cell growth by blocking the cell cycle at the G1 phase.

Cell cycle-coupled expansion of AR activity promotes cancer progression.

The androgen receptor (AR) is required for prostate cancer (PCa) survival and progression, and ablation of AR activity is the first line of therapeutic intervention for disseminated disease. While initially effective, recurrent tumors ultimately arise for which there is no durable cure. Despite the dependence of PCa on AR activity throughout the course of disease, delineation of the AR-dependent transcriptional network that governs disease progression remains elusive, and the function of AR in mitotically active cells is not well understood. Analyzing AR activity as a function of cell cycle revealed an unexpected and highly expanded repertoire of AR-regulated gene networks in actively cycling cells. New AR functions segregated into two major clusters: those that are specific to cycling cells and retained throughout the mitotic cell cycle (“Cell Cycle Common”), versus those that were specifically enriched in a subset of cell cycle phases (“Phase Restricted”). Further analyses identified previously unrecognized AR functions in major pathways associated with clinical PCa progression. Illustrating the impact of these unmasked AR-driven pathways, dihydroceramide-desaturase 1 (DEGS1) was identified as an AR regulated gene in mitotically active cells that promoted pro-metastatic phenotypes, and in advanced PCa proved to be highly associated with development of metastases, recurrence after therapeutic intervention, and reduced overall survival. Taken together, these findings delineate AR function in mitotically active tumor cells, thus providing critical insight into the molecular basis by which AR promotes development of lethal PCa and nominate new avenues for therapeutic intervention.

Abstract B42: Autocrine/paracrine RANKL-RANK signaling promotes cancer bone metastasis and establishes premetastatic niche recruiting bystander cancer cells to participate in the metastatic process

Abstract RANKL-elicited RANK activity plays critical roles in many biological and pathological conditions, including osteoclast differentiation/bone remodeling, lymph node/thymic development, central thermoregulation and progesterone-driven mammary gland maturation, differentiation and carcinogenesis. RANKL can be derived from osteoblasts, infiltrating inflammatory cells and stromal fibroblasts. We previously showed that malignant prostate cancer (PCa) cells expressed RANKL and that its expression was correlated with clinical PCa progression and bone metastasis. RANKL expression at the single cell level in primary PCa specimens predicts PCa patient survival. We demonstrated RANKL overexpression promoted epithelial-to-mesenchymal transition (EMT), stem cells, and neuroendocrine (NE) phenotypes of PCa cells through transactivation of c-Myc/Max and AP4 via RANK-mediated signaling and conferred PCa bone and soft tissue metastases in mice. Blockade of RANKL-RANK signaling as well as their downstream regulators abolished the metastasis of PCa induced by RANKL. Furthermore, recombinant RANKL protein alone is sufficient to induce bone colonization and growth of RANKL- and non-metastatic PCa and breast cancer cells. Even a few RANKL+ PCa cells are sufficient to initiate the in vivo metastatic cascade by recruiting non-tumorigenic RANKL- PCa cells to participate in the metastatic process via downstream signaling amplification, implicating metastasis-initiating properties of RANKL-expressing PCa cells. Recently, we further demonstrated that RANKL rendered metastatic potential to breast, lung, renal, and liver cancer cells and promote their metastases to bone and other soft tissues in mice. Collectively, these results demonstrated RANKL is a uniform factor that drives bone metastasis of many different cancers, including prostate, breast, lung, renal, and liver cancers. The autocrine/paracrine RANKL-RANK signaling in cancer cells establishes a premetastatic niche through a “vicious cycle”, inducing RANKL and c-Met expression via activation of c-Myc/Max, and this promotes PCa EMT progression, stem and NE cell properties, and bone and soft tissue metastases. RANKL-expressing cancer cells possess metastasis-initiating potential that recruits and reprograms bystander non-tumorigenic cells to participate in the metastatic process. RANKL expression status therefore offers new insights for dissecting the mechanism by which PCa cells exhibit propensity for bone colonization/metastasis. Citation Format: Gina Chia-Yi Chu, Haiyen E. Zhau, Ruoxiang Wang, Leland W.K. Chung. Autocrine/paracrine RANKL-RANK signaling promotes cancer bone metastasis and establishes premetastatic niche recruiting bystander cancer cells to participate in the metastatic process. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr B42.

Prognostic role of genetic biomarkers in clinical progression of prostate cancer.

The aim of this study was to analyze the use of 12 single-nucleotide polymorphisms in genes ELAC2, RNASEL and MSR1 as biomarkers for prostate cancer (PCa) detection and progression, as well as perform a genetic classification of high-risk patients. A cohort of 451 men (235 patients and 216 controls) was studied. We calculated means of regression analysis using clinical values (stage, prostate-specific antigen, Gleason score and progression) in patients and controls at the basal stage and after a follow-up of 72 months. Significantly different allele frequencies between patients and controls were observed for rs1904577 and rs918 (MSR1 gene) and for rs17552022 and rs5030739 (ELAC2). We found evidence of increased risk for PCa in rs486907 and rs2127565 in variants AA and CC, respectively. In addition, rs627928 (TT–GT), rs486907 (AG) and rs3747531 (CG–CC) were associated with low tumor aggressiveness. Some had a weak linkage, such as rs1904577 and rs2127565, rs4792311 and rs17552022, and rs1904577 and rs918. Our study provides the proof-of-principle that some of the genetic variants (such as rs486907, rs627928 and rs2127565) in genes RNASEL, MSR1 and ELAC2 can be used as predictors of aggressiveness and progression of PCa. In the future, clinical use of these biomarkers, in combination with current ones, could potentially reduce the rate of unnecessary biopsies and specific treatments.

Are Biochemical Recurrence Outcomes Similar After Radical Prostatectomy and Radiation Therapy? Analysis of Prostate Cancer–Specific Mortality by Nomogram-predicted Risks of Biochemical Recurrence

BackgroundDue to the protracted natural history of the clinical progression of prostate cancer, biochemical recurrence (BCR) is often used to compare treatment modalities. However, BCR definitions and posttreatment prostate-specific antigen kinetics vary considerably among treatments, calling into the question the validity of such comparisons. ObjectiveTo analyze prostate cancer–specific mortality (PCSM) according to treatment-specific nomogram-predicted risk of BCR for men treated by radical prostatectomy (RP), external-beam radiation therapy (EBRT), and brachytherapy. Design, setting, and participantsA total of 13 803 men who underwent RP, EBRT, or brachytherapy at two US high-volume hospitals between 1995 and 2008. InterventionRP, EBRT, and brachytherapy. Outcome measurements and statistical analysisThe 5-yr progression-free probability (5Y-PFP) was calculated for each patient based on the treatment received using a validated treatment-specific nomogram. Fine and Gray competing risk analysis was then used to estimate PCSM by a patient's predicted 5Y-PFP. Multivariable competing risk regression analysis was used to determine the association of treatment with PCSM after adjusting for nomogram-predicted 5Y-PFP. Results and limitationsMen receiving EBRT had higher 10-yr PCSM compared with those treated by RP across the range of nomogram-predicted risks of BCR: 5Y-PFP >75%, 3% versus 0.9%; 5Y-PFP 51–75%, 6.8% versus 5.9%; 5Y-PFP 26–50%, 12.2% versus 10.6%; and 5Y-PFP ≤25%, 26.6% versus 21.2%. After adjusting for nomogram-predicted 5Y-PFP, EBRT was associated with a significantly increased PCSM risk compared with RP (hazard ratio: 1.5; 95% confidence interval, 1.1–2.0; p=0.006). No statistically significant difference in PCSM was observed between patients treated by brachytherapy and RP, although patient selection factors and lack of statistical power limited this analysis. ConclusionsEBRT patients with similar nomogram-predicted 5Y-PFP appear to have a significantly increased risk of PCSM compared with those treated by RP. Comparison of treatments using nomogram-predicted BCR end points may not be valid. Patient summaryBiochemical recurrence (BCR) outcomes after external-beam radiation therapy and radical prostatectomy are associated with different risks of subsequent prostate cancer–specific mortality. Physicians and patients should cautiously interpret BCR end points when comparing treatments to make treatment decisions.

Abstract 3942: Autocrine/paracrine RANKL-RANK signaling promotes cancer bone metastasis and establishes premetastatic niche recruiting bystander cancer cells to participate in the metastatic process.

Abstract RANKL-elicited RANK activity plays critical roles in many biological and pathological conditions, including osteoclast differentiation/bone remodeling, lymph node/thymic development, central thermoregulation and progesterone-driven mammary gland maturation, differentiation and carcinogenesis. RANKL can be derived from osteoblasts, infiltrating inflammatory cells and stromal fibroblasts. We previously showed that malignant prostate cancer (PCa) cells expressed RANKL and that its expression was correlated with clinical PCa progression and bone metastasis. The present study examined whether PCa-derived RANKL acts on RANK+ PCa cells to promote PCa bone metastasis. We demonstrated several interesting key findings for RANKL-RANK signaling in PCa cells: 1) RANKL overexpression in human PCa LNCaP and ARCaPE cells results in increased RANKL-RANK signaling within PCa cells and confers PCa bone and soft tissue metastases in a tumor cell RANK-dependent manner since RANK knockdown in RANKL-expressing PCa cells fails to induce bone colonization or metastasis. 2) RANKL amplifies downstream signaling by activating RANKL and c-Met expression through a common transcription factor complex, c-Myc/Max, which was identified by site-directed mutagenesis and transcription factor deletion/interference assays. 3) Even a few RANKL+ PCa cells are sufficient to initiate the in vivo metastatic cascade by recruiting non-tumorigenic RANKL− PCa cells to participate in the metastatic process via downstream signaling amplification. This is supported by the observation that recombinant RANKL protein alone is sufficient to induce bone colonization and growth of RANKL− and non-metastatic PCa cells. 4) RANKL also promotes EMT and confers stem and neuroendocrine (NE) cell properties on participating cancer cells determined by changes in their specific markers. 5) In support of the roles of RANKL-RANK signaling in PCa bone metastasis, RANKL expression at the single cell level in primary PCa specimens predicts PCa patient survival. Collectively, these results demonstrated that autocrine/paracrine RANKL-RANK signaling in PCa cells establishes a premetastatic niche through a “vicious cycle," inducing RANKL and c-Met expression via activation of c-Myc/Max, and this promotes PCa EMT progression, stem and NE cell properties, and PCa bone and soft tissue metastases. RANKL expression status therefore offers new insights for dissecting the mechanism by which PCa cells exhibit propensity for bone colonization/metastasis. (Funding supported in part by R01 CA122602 and P01 CA098912 grants) Citation Format: Gina C.Y. Chu, Haiyen E. Zhau, Ruoxiang Wang, Andre Rogatko, Xu Feng, Majd Zayzafoon, Leland W.K. Chung. Autocrine/paracrine RANKL-RANK signaling promotes cancer bone metastasis and establishes premetastatic niche recruiting bystander cancer cells to participate in the metastatic process. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3942. doi:10.1158/1538-7445.AM2013-3942

197 PREMETASTATIC NICHE INVOLVES RANKL-RANK SIGNALING RECRUITING BYSTANDER CANCER CELLS TO PARTICIPATE CANCER SKELETAL METASTASIS

You have accessJournal of UrologyProstate Cancer: Basic Research (I)1 Apr 2013197 PREMETASTATIC NICHE INVOLVES RANKL-RANK SIGNALING RECRUITING BYSTANDER CANCER CELLS TO PARTICIPATE CANCER SKELETAL METASTASIS Gina C.Y. Chu, Haiyen E. Zhau, Ruoxiang Wang, Andre Rogatko, Xu Feng, Majd Zayzafoon, and Leland W.K. Chung Gina C.Y. ChuGina C.Y. Chu Los Angeles, CA More articles by this author , Haiyen E. ZhauHaiyen E. Zhau Los Angeles, CA More articles by this author , Ruoxiang WangRuoxiang Wang Los Angeles, CA More articles by this author , Andre RogatkoAndre Rogatko Los Angeles, CA More articles by this author , Xu FengXu Feng Birmingham, AL More articles by this author , Majd ZayzafoonMajd Zayzafoon Birmingham, AL More articles by this author , and Leland W.K. ChungLeland W.K. Chung Los Angeles, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.1577AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Activation of RANK, a receptor activator of NF-κB, by its ligand RANKL is critical for osteoclast differentiation/bone remodeling. RANKL can be derived from osteoblasts, infiltrating inflammatory cells and stromal fibroblasts. We found malignant prostate cancer (PCa) cells expressed RANKL; its expression correlated with clinical PCa progression and induced bone metastasis (BM) of RANK+ PCa cells. Our objective is to dissect the mechanism by which PCa-derived RANKL acts on RANK+ PCa cells to promote PCa BM. METHODS Human PCa LNCaP cells were stably transfected with a RANKL expression construct. We identified the common transcription factors (TFs) required for the induction of RANKL and c-Met expression by site-directed mutagenesis and TFs deletion/interference assays. We assessed EMT progression, stem, and neuroendocrine (NE) cell properties by determining changes in their specific markers. Tumorigenic and metastatic potential in vivo was examined by intratibial and intracardiac co-inoculation of RANKL+ and RANKL- PCa cells to male athymic mice. RANKL expression was detected by quantum dot staining and cell-based signal quantification from 20 primary PCa specimens with documented cancer-specific survival data. RESULTS We demonstrated that: 1) RANKL amplifies downstream signaling by activating RANKL and c-Met expression and signaling through a common TF complex, c-Myc/Max. 2) A few RANKL+ PCa cells are sufficient to initiate the metastatic cascade by recruiting non-tumorigenic RANKL- PCa cells to participate in the metastatic process via downstream signaling amplification. This is supported by the observation that recombinant RANKL protein alone is sufficient to induce BM of non-metastatic PCa cells. 3) RANKL also promotes EMT and confers stem and NE cell properties on participating cancer cells.4) RANKL expression at the single cell level in primary PCa specimens predicts PCa patient survival. CONCLUSIONS Small numbers of RANKL+ PCa cells are sufficient to initiate cancer bone colonization by recruiting non-tumorigenic/bystander PCa cells to participate in BM. RANKL-RANK signaling in PCa cells establishes a premetastatic niche through a “vicious cycle”, inducing RANKL and c-Met expression via activation of c-Myc/Max. RANKL-RANK interaction promotes PCa cells to undergo EMT and assume stem and NE cell properties. RANKL expression at the single cell level in primary human cancer tissues predicts PCa patient survival. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e81-e82 Peer Review Report Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Gina C.Y. Chu Los Angeles, CA More articles by this author Haiyen E. Zhau Los Angeles, CA More articles by this author Ruoxiang Wang Los Angeles, CA More articles by this author Andre Rogatko Los Angeles, CA More articles by this author Xu Feng Birmingham, AL More articles by this author Majd Zayzafoon Birmingham, AL More articles by this author Leland W.K. Chung Los Angeles, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The risks, degree of malignancy and clinical progression of prostate cancer associated with the MDM2 T309G polymorphism: a meta-analysis

To determine the risk, malignant degree and clinical progression of prostate cancer (PCa) associated with mouse double-minute 2 protein (MDM2) T309G variants, a meta-analysis was performed on all eligible published studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess these associations in seven studies that included 5151 cases and 1003 controls. In the overall analysis, the 309G allele was significantly associated with a decreased PCa risk (OR=0.85, 95% CI: 0.74-0.97); this was also the case for the homozygous comparison (OR=0.72, 95% CI: 0.55-0.95) and the dominant genetic model (OR=0.79, 95% CI: 0.65-0.96). The 309G allele was also found to be significantly associated with lower degrees of PCa malignancy (OR=0.85, 95% CI: 0.75-0.96) in the overall analysis, as well as in the heterozygous comparison (OR=0.79, 95% CI: 0.65-0.96), homozygous comparison (OR=0.76, 95% CI: 0.58-0.98) and dominant genetic model (OR=0.81, 95% CI: 0.68-0.96). Furthermore, grouping analysis showed that the 309G allele in Caucasians was significantly correlated with a decreased PCa risk (OR=0.77, 95% CI: 0.61-0.96); this was also the case in the homozygous comparison (OR=0.51, 95% CI: 0.31-0.86). The grouping analysis also showed that the 309G variant in Caucasians was significantly associated with a lower degree of PCa malignancy in all of the genetic models. In addition, we found that the 309G variant in Caucasians was significantly associated with a slower PCa clinical progression in all of the genetic models. In summary, our meta-analysis showed that the MDM2 309G variant was significantly associated with a decreased PCa risk, lower malignant degree and slower clinical progression in Caucasians, but there was no obvious association in the Asian population.

Mitosis Phase Enrichment with Identification of Mitotic Centromere-Associated Kinesin As a Therapeutic Target in Castration-Resistant Prostate Cancer

The recently described transcriptomic switch to a mitosis program in castration-resistant prostate cancer (CRPC) suggests that mitotic proteins may be rationally targeted at this lethal stage of the disease. In this study, we showed upregulation of the mitosis-phase at the protein level in our cohort of 51 clinical CRPC cases and found centrosomal aberrations to also occur preferentially in CRPC compared with untreated, high Gleason–grade hormone-sensitive prostate cancer (P<0.0001). Expression profiling of chemotherapy-resistant CRPC samples (n = 25) was performed, and the results were compared with data from primary chemotherapy-naïve CRPC (n = 10) and hormone-sensitive prostate cancer cases (n = 108). Our results showed enrichment of mitosis-phase genes and pathways, with progression to both castration-resistant and chemotherapy-resistant disease. The mitotic centromere-associated kinesin (MCAK) was identified as a novel mitosis-phase target in prostate cancer that was overexpressed in multiple CRPC gene-expression datasets. We found concordant gene expression of MCAK between our parent and murine CRPC xenograft pairs and increased MCAK protein expression with clinical progression of prostate cancer to a castration-resistant disease stage. Knockdown of MCAK arrested the growth of prostate cancer cells suggesting its utility as a potential therapeutic target.

1610 STATINS REDUCE THE RISK OF PROSTATE CANCER PROGRESSION: AN IN VITRO STUDY IN TO THE MECHANISM OF METASTASIS

INTRODUCTION AND OBJECTIVES: Exposure of cancer cells to statins result in the down-regulation of the mevalonate pathway by HMG-CoA reductase inhibition, inducing inhibition of a range of cellular functions such as membrane integrity, cell signalling, protein synthesis and cell cycle progression. Disruption of these processes may result in changes in the regulation of tumour initiation, growth and metastasis. Clinical studies have reported that statins do not effect the incidence of clinically significant prostate cancer but usage reduces the risk of progression and mortality (0.26; 95% CI 0.08–0.83 0.64; 95% CI 0.44–0.93). It is currently unclear how statins reduce the clinical progression of prostate cancer. Here we present in vitro data showing that statins act directly on the prostate epithelial cells, reducing their ability to invade through and form metastatic colonies in the bone marrow stroma (BMS). METHODS: BMS was isolated with ethical approval from consenting patients undergoing surgery for non-malignant disease. All statins were used at non-toxic doses as determined by colony forming assays (atorvastatin, mevastatin, simvastatin (1 M), rosuvastatin (5 M) & pravastatin (100 M)). Binding of statin treated PC-3GFP cells to BMS was assessed using a FLUOstar OPTIMA spectrometer. Invasion of statin treated PC-3 cells towards untreated BMS or 7 day statin pre-treated BMS was assessed using the FluoroBlok tumour co-culture cell invasion system. Colony formation was assessed by seeding statin treated PC-3 cells on to confluent BMS. Statins were refreshed daily for 8 days before fixing and staining with anti pancytokeratin, counting and measuring epithelial colonies. RESULTS: Statins do not affect the ability of PC-3 cells to bind to BMS. Pravastatin had no effect on PC-3 invasion or colony formation in BMS. Treating PC-3 cells with atorvastatin, mevastatin, simvastatin and rosuvastatin significantly reduced their ability to invade towards BMS as compared with untreated controls on average 66.68% (range 53.93%–77.04% p 0.05). These statins also significantly reduced the number (76.2 vs 118; p 0.05) and size (0.2mm vs 0.29mm; p 0.05) of colonies formed in BMS co-culture, with colonies displaying a more compact morphology indicative of a reduction in the ability to migrate through the BMS. CONCLUSIONS: Statins reduce the risk of prostate cancer progression by inhibiting the ability of malignant prostate epithelial cells to invade towards and through human BMS, reducing the formation and the spread of metastatic prostate colonies.

Abstract 1439: De novo expression of c-kit in prostate cancer cells interacting with the bone microenvironment

Abstract Specific cellular and molecular interactions between prostate cancer (PC) cells and the bone microenvironment lead to expansion of the metastatic deposit, disease progression, and ultimately significant morbidity and mortality. We recently reported an association between expression of the tyrosine kinase receptor c-kit and clinical PC progression, with the highest expression seen in clinical metastatic bone specimens. Moreover, we found that intraosseous tumors formed by otherwise c-kit negative PC3 cells injected into human bone xenografts in SCID mice (SCID-hu model) expressed c-kit. To determine the relevance of these findings, we examined additional human PC cell lines, namely LNCaP, C42b, and DU145, for the expression of c-kit in vitro and in vivo. While none of the cultured PC cells expressed c-kit at the message or protein level, immunostaining for c-kit in intraosseous tumors produced by these cells in the SCID-hu model revealed a distinctive and specific reactivity in the cancer cell compartment. The induction of c-kit expression in PC cells growing within the bone microenvironment was emulated by co-culture of PC3 cells and bone-derived cells embedded in Matrigel, as demonstrated by RT-PCR analysis. In an attempt to mimic the de novo c-kit expression observed in the SCID-hu model and to identify potential signaling pathways triggered by c-kit activation by its ligand stem cell factor (SCF), normally expressed by the bone microenvironment, we transiently transfected PC3 cells with wild-type c-kit. Activation of c-kit was confirmed by immunoblotting for phosphorylated c-kit. Using the whole human genome Agilent microarray, we found that 220 genes were differentially expressed when SCF-treated and non-treated c-kit-transfected PC3 cells were compared, resulting in discrete functional sub-networks that were coordinately up or down-regulated. Most notably, pathway and genetic network analysis revealed that c-kit activation resulted in an up-regulated fibroblast growth factor-2-mediated sub-network. Taken together, these results suggest that c-kit induction in PC cells in the bone microenvironment modulates cell-cell interaction pathways and growth factor signaling systems that ultimately lead to expansion of bone metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1439.

ORIGINAL RESEARCH—ENDOCRINOLOGY: Two Years of Testosterone Therapy Associated with Decline in Prostate-Specific Antigen in a Man with Untreated Prostate Cancer

Testosterone (T) therapy has long been considered contraindicated in men with prostate cancer (PCa). However, the traditional view regarding the relationship of T to PCa has come under new scrutiny, with recent reports suggesting that PCa growth may not be greatly affected by variations in serum T within the near-physiologic range. This report details the clinical and prostate-specific antigen (PSA) response of a man with untreated PCa treated with T therapy for 2 years. Measurements of serum PSA, total and free T concentrations were obtained at regular intervals at baseline and following initiation of T therapy. Serum PSA during T therapy. An 84-year-old man was seen for symptoms of hypogonadism, with serum total T within the normal range at 400 ng/dL, but with a reduced free T of 7.4 pg/mL (radioimmunoassay [RIA], reference range 10.0-55.0). PSA was 8.5 ng/mL, and 8.1 ng/mL when repeated. Prostate biopsy revealed Gleason 6 cancer in both lobes. He refused treatment for PCa, but requested T therapy, which was initiated with T gel after informed consent regarding possible cancer progression. Serum T increased to a mean value of 699 ng/dL and free T to 17.1 pg/mL. PSA declined to a nadir of 5.2 ng/mL at 10 months, increased slightly to 6.2 ng/mL at 21 months, and then declined to 3.8 ng/mL at 24 months after addition of dutasteride for voiding symptoms. No clinical PCa progression was noted. A decline in PSA was noted in a man with untreated PCa who received T therapy for 2 years. This case provides support for the notion that PCa growth may not be adversely affected by changes in serum T beyond the castrate or near-castrate range.

CHEMOPREVENTION OF HUMAN PROSTATE CANCER BY ORAL ADMINISTRATION OF GREEN TEA CATECHINS: A TRANSLATIONAL RESEARCH STORY

Clinical progression of Prostate Cancer (CaP) is variable: some tumours are indolent, others&#x0D; rapidly progress. Because, diagnosis is usually in elderly men, CaP is an ideal target for&#x0D; chemoprevention. We showed that Green Tea Catechins (GTC) possess anti-tumour activity,&#x0D; suggesting that it might be beneficial in the early stages of cell transformation. But an experimental&#x0D; confirmation in a real clinical setting was needed. High-Grade Prostatic Intraepithelial Neoplasia&#x0D; (HGPIN) is a pre-invasive stage of CaP for which no treatment options are available until CaP is&#x0D; diagnosed.

C-Kit and Its Ligand Stem Cell Factor: Potential Contribution to Prostate Cancer Bone Metastasis

The tyrosine kinase receptor c-kit and its ligand stem cell factor (SCF) have not been explored in prostate cancer (PC) bone metastasis. Herein, we found that three human PC cell lines and bone marrow stromal cells express a membrane-bound SCF isoform and release a soluble SCF. Bone marrow stromal cells revealed strong expression of c-kit, whereas PC cells showed very low levels of the receptor or did not express it all. Using an experimental model of PC bone metastasis, we found that intraosseous bone tumors formed by otherwise c-kit–negative PC3 cells strongly expressed c-kit, as demonstrated using immunohistochemical and Western blot analyses. Subcuta-neous PC3 tumors were, however, c-kit–negative. Both bone and subcutaneous PC3 tumors were positive for SCF. Immunohistochemical analysis of human specimens revealed that the expression frequency of c-kit in epithelial cells was of 5% in benign prostatic hyperplasia, 14% in primary PC, and 40% in PC bone metastases, suggesting an overall trend of increased c-kit expression in clinical PC progression. Stem cell factor expression frequency was more than 80% in all the cases. Our data suggest that the bone microenvironment up-regulates c-kit expression on PC cells, favoring their intraosseous expansion.

Signal transducer and activator of transcription 5A/B in prostate and breast cancers

Protein kinase signaling pathways, such as Janus kinase 2-Signal transducer and activator of transcription 5A/B (JAK2-STAT5A/B), are of significant interest in the search for new therapeutic strategies in both breast and prostate cancers. In prostate cancer, the components of the JAK2-STAT5A/B signaling pathway provide molecular targets for small-molecule inhibition of survival and growth signals of the cells. At the same time, new evidence suggests that the STAT5A/B signaling pathway is involved in the transition of organ-confined prostate cancer to hormone-refractory disease. This implies that the active JAK2-STAT5A/B signaling pathway potentially provides the means for pharmacological intervention of clinical prostate cancer progression. In addition, active STAT5A/B may serve as a prognostic marker for identification of those primary prostate cancers that are likely to progress to aggressive disease. In breast cancer, the role of STAT5A/B is more complex. STAT5A/B may have a dual role in the regulation of malignant mammary epithelium. Data accumulated from mouse models of breast cancer suggest that in early stages of breast cancer STAT5A/B may promote malignant transformation and enhance growth of the tumor. This is in contrast to established breast cancer, where STAT5A/B may mediate the critical cues for maintaining the differentiation of mammary epithelium. In addition, present data suggest that activation of STAT5A/B in breast cancer predicts favorable clinical outcome. The dual nature of STAT5A/B action in breast cancer makes the therapeutic use of STAT5 A/B more complex.

Loss of neutral endopeptidase and activation of protein kinase B (Akt) is associated with prostate cancer progression

Neutral endopeptidase (NEP) is a cell-surface peptidase that can regulate the activation of Akt kinase through catalytic-dependent and independent mechanisms. NEP expression is absent in approximately 50% of prostate cancers. The authors investigated whether NEP loss in vivo would result in Akt phosphorylation and potentially contribute to prostate cancer progression by examining the interaction of NEP, Akt, and phosphatase and tensin homolog (PTEN) in a prostate xenograft model and in clinical specimens from patients with prostate cancer. Using a tetracycline-repressible expression system to express NEP in a tumor animal xenograft model, the effects of NEP were tested on tumor growth, Akt phosphorylation, and PTEN expression. The clinical relevance of NEP, phosphorylated Akt, and PTEN protein expression also was investigated in 204 patients who had undergone radical prostatectomy. The results indicated that the induction of NEP expression inhibited established xenograft tumor growth, diminished Akt phosphorylation, and increased PTEN protein levels. In humans, prostate cancers with complete loss of NEP expression were significantly more likely to express phosphorylated Akt (P = .02). Moreover, patients who had prostate cancers with concomitant loss of NEP and expression of phosphorylated Akt had an increased, independent risk of prostate-specific antigen (PSA) recurrence (P = .03). In the study cohort, loss of PTEN protein expression did not correlated significantly with phosphorylated Akt or with patients' clinical outcome. The findings from this investigation demonstrated that NEP loss leads to Akt activation and contributes to the clinical progression of prostate cancer.