Link between circadian rhythm and benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS).

BACKGROUND: Benign prostatic hyperplasia (BPH) is the most common urologic disease in aging males, affecting 50% of men over 50 and up to 80% of men over 80 years old. Its negative impact on health-related quality of life implores further investigation into its risk factors and strategies for effective management. Although the exact molecular mechanisms underlying pathophysiological onset of BPH are poorly defined, the current hypothesized contributors to BPH and lower urinary tract symptoms (LUTS) include aging, inflammation, metabolic syndrome, and hormonal changes. These processes are indirectly influenced by circadian rhythm disruption. In this article, we review the recent evidence on the potential association of light changes/circadian rhythm disruption and the onset of BPH and impact on treatment. METHODS: A narrative literature review was conducted using PubMed and Google Scholar to identify supporting evidence. The articles referenced ranged from 1975 to 2023. RESULTS: A clear relationship between BPH/LUTS and circadian rhythm disruption is yet to be established. However, common mediators influence both diseases, including proinflammatory states, metabolic syndrome, and hormonal regulation that can be asserted to circadian disruption. Some studies have identified a possible relationship between general LUTS and sleep disturbance, but little research has been done on the medical management of these diseases and how circadian rhythm disruption further affects treatment outcomes. CONCLUSIONS: There is evidence to implicate a relationship between BPH/LUTS and circadian rhythm disruptions. However, there is scarce literature on potential specific link in medical management of the disease and treatment outcomes with circadian rhythm disruption. Further study is warranted to provide BPH patients with insights into circadian rhythm directed appropriate interventions.

Prostate cancer in transgender women: considerations for screening, diagnosis and management.

Transgender individuals represent 0.55% of the US population, equivalent to 1.4 million transgender adults. In transgender women, feminisation can include a number of medical and surgical interventions. The main goal is to deprive the phenotypically masculine body of androgens and simultaneously provide oestrogen therapy for feminisation. In gender-confirming surgery (GCS) for transgender females, the prostate is usually not removed. Due to limitations of existing cohort studies, the true incidence of prostate cancer in transgender females is unknown but is thought to be less than the incidence among cis-gender males. It is unclear how prostate cancer develops in androgen-deprived conditions in these patients. Six out of eleven case reports in the literature presented with metastatic disease. It is thought that androgen receptor-mediated mechanisms or tumour-promoting effects of oestrogen may be responsible. Due to the low incidence of prostate cancer identified in transgender women, there is little evidence to drive specific screening recommendations in this patient subpopulation. The treatment of early and locally advanced prostate cancer in these patients warrants an individualised thoughtful approach with input from patients' reconstructive surgeons. Both surgical and radiation treatment for prostate cancer in these patients can profoundly impact the patient's quality of life. In this review, we discuss the evidence surrounding screening and treatment of prostate cancer in transgender women and consider the current gaps in our knowledge in providing evidence-based guidance at the molecular, genomic and epidemiological level, for clinical decision-making in the management of these patients.

When to order genomic tests: development and external validation of a model to predict high-risk prostate cancer at the genotypic level.

PURPOSE: The aim of this study was to develop a model to predict high-genomic-risk prostate cancer (PCa) according to Decipher score, a validated 22 gene prognostic panel. By doing so, one might select the individuals who are likely to benefit from genomic testing and improve pre-op counseling about the need for adjuvant treatments. METHODS: We retrospectively reviewed IRB-approved databases at two institutions. All patients had preoperative magnetic resonance imaging (MRI) and Decipher prostate radical prostatectomy (RP), a validated 22 gene prognostic panel. We used binary logistic regression to estimate high-risk Decipher (Decipher score > 0.60) probability on RP specimen. Area under the curve (AUC) and calibration were used to assess the accuracy of the model in the development and validation cohort. Decision curve analysis (DCA) was performed to assess the clinical benefit of the model. RESULTS: The development and validation cohort included 622 and 185 patients with 283 (35%) and 80 (43%) of those with high-risk Decipher. The multivariable model included PSA density, biopsy Gleason Grade Group, percentage of positive cores and MRI extracapsular extension. AUC was 0.73 after leave-one-out cross-validation. DCA showed a clinical benefit in a range of probabilities between 15 and 60%. In the external validation cohort, AUC was 0.70 and calibration showed that the model underestimates the actual probability of the outcome. CONCLUSIONS: The proposed model to predict high-risk Decipher score at RP is helpful to improve risk stratification of patients with PCa and to assess the need for additional testing and treatments.

Association between Expression of Connective Tissue Genes and Prostate Cancer Growth and Progression.

To find an association between genomic features of connective tissue and pejorative clinical outcomes on radical prostatectomy specimens. We performed a retrospective analysis of patients who underwent radical prostatectomy and underwent a Decipher transcriptomic test for localized prostate cancer in our institution (n = 695). The expression results of selected connective tissue genes were analyzed after multiple t tests, revealing significant differences in the transcriptomic expression (over- or under-expression). We investigated the association between transcript results and clinical features such as extra-capsular extension (ECE), clinically significant cancer, lymph node (LN) invasion and early biochemical recurrence (eBCR), defined as earlier than 3 years after surgery). The Cancer Genome Atlas (TCGA) was used to evaluate the prognostic role of genes on progression-free survival (PFS) and overall survival (OS). Out of 528 patients, we found that 189 had ECE and 27 had LN invasion. The Decipher score was higher in patients with ECE, LN invasion, and eBCR. Our gene selection microarray analysis showed an overexpression in both ECE and LN invasion, and in clinically significant cancer for COL1A1, COL1A2, COL3A1, LUM, VCAN, FN1, AEBP1, ASPN, TIMP1, TIMP3, BGN, and underexpression in FMOD and FLNA. In the TCGA population, overexpression of these genes was correlated with worse PFS. Significant co-occurrence of these genes was observed. When presenting overexpression of our gene selection, the 5-year PFS rate was 53% vs. 68% (p = 0.0315). Transcriptomic overexpression of connective tissue genes correlated to worse clinical features, such as ECE, clinically significant cancer and BCR, identifying the potential prognostic value of the gene signature of the connective tissue in prostate cancer. TCGAp cohort analysis showed a worse PFS in case of overexpression of the connective tissue genes.

Clinical Significance of Extracellular Vesicles in Prostate and Renal Cancer.

Extracellular vesicles (EVs)-including apoptotic bodies, microvesicles, and exosomes-are released by almost all cell types and contain molecular footprints from their cell of origin, including lipids, proteins, metabolites, RNA, and DNA. They have been successfully isolated from blood, urine, semen, and other body fluids. In this review, we discuss the current understanding of the predictive value of EVs in prostate and renal cancer. We also describe the findings supporting the use of EVs from liquid biopsies in stratifying high-risk prostate/kidney cancer and advanced disease, such as castration-resistant (CRPC) and neuroendocrine prostate cancer (NEPC) as well as metastatic renal cell carcinoma (RCC). Assays based on EVs isolated from urine and blood have the potential to serve as highly sensitive diagnostic studies as well as predictive measures of tumor recurrence in patients with prostate and renal cancers. Overall, we discuss the biogenesis, isolation, liquid-biopsy, and therapeutic applications of EVs in CRPC, NEPC, and RCC.

Prostate MRI percentage tumor involvement or "PI-RADS percent" as a predictor of adverse surgical pathology.

BACKGROUND: This study assesses magnetic resonance imaging (MRI) prostate % tumor involvement or "PI-RADs percent" as a predictor of adverse pathology (AP) after surgery for localized prostate cancer (PCa). Two separate variables, "All PI-RADS percent" (APP) and "Highest PI-RADS percent" (HPP), are defined as the volume of All PI-RADS 3-5 score lesions on MRI and the volume of the Highest PI-RADS 3-5 score lesion each divided by TPV, respectively. METHOD: An analysis was done of an IRB approved prospective cohort of 557 patients with localized PCa who had targeted biopsy of MRI PIRADs 3-5 lesions followed by RARP from April 2015 to May 2020 performed by a single surgeon at a single center. AP was defined as ISUP GGG ≥3, pT stage ≥T3 and/or LNI. Univariate and multivariable analyses were used to evaluate APP and HPP at predicting AP with other clinical variables such as Age, PSA at surgery, Race, Biopsy GGG, mpMRI ECE and mpMRI SVI. Internal and External Validation demonstrated predicted probabilities versus observed probabilities. RESULTS: AP was reported in 44.5% (n = 248) of patients. Multivariable regression showed both APP (odds ratio [OR]: 1.10, 95% confidence interval [CI]: 1.04-1.14, p = 0.0007) and HPP (OR: 1.10; 95% CI: 1.04-1.16; p = 0.0007) were significantly associated with AP with individual area under the operating curves (AUCs) of 0.6142 and 0.6229, respectively, and AUCs of 0.8129 and 0.8124 when incorporated in models including preoperative PSA and highest biopsy GGG. CONCLUSIONS: Increasing PI-RADS Percent was associated with a higher risk of AP, and both APP and HPP may have clinical utility as predictors of AP in GGG 1 and 2 patients being considered for AS. PATIENT SUMMARY: Using PIRADs percent to predict AP for presurgical patients may help risk stratification, and for low and low volume intermediate risk patients, may influence treatment decisions.

Association between chronic kidney disease and COVID-19-related mortality in New York.

PURPOSE: To evaluate mortality risk of CKD patients infected with COVID-19, and assess shared characteristics associated with health disparities in CKD outcome. METHODS: We extracted the data from a case series of 7624 patients presented at Mount Sinai Health System, in New York for testing between 3/28/2020 and 4/16/2020. De-identified patient data set is being produced by the Scientific Computing department and made available to the Mount Sinai research community at the following website: https://msdw.mountsinai.org/ . RESULTS: Of 7624 COVID-19 patients, 7.8% (n = 597) had CKD on hospital admission, and 11.2% (n = 856) died of COVID-19 infection. CKD patients were older, more likely to have diabetes, hypertension, and chronic obstructive pulmonary disease (COPD), were current or former smokers, had a longer time to discharge, and had worse survival compared to non-CKD patients (p < 0.05). COVID-19 mortality rate was significantly higher in CKD patients (23.1% vs 10.2%) with a 1.51 greater odds of dying (95% CI: 1.19-1.90). Controlling for demographic, behavioral, and clinical covariates, the logistic regression analysis showed significant and consistent effects of CKD, older age, male gender, and hypertension with mortality (p < 0.05). CONCLUSION: CKD was a significant independent predictor of COVID-19 mortality, along with older age, male gender, and hypertension. Future research will investigate the effects of COVID-19 on long-term renal function.

Deciphering Evolutionary Dynamics and Lineage Plasticity in Aggressive Prostate Cancer.

This Special Issue focuses on the molecular mechanisms involved in therapeutic resistance, lineage plasticity, and phenotypic reprogramming leading to prostate cancer recurrence and, ultimately, lethal disease [...].

Non-Coding RNAs Set a New Phenotypic Frontier in Prostate Cancer Metastasis and Resistance.

Prostate cancer (PCa) mortality remains a significant public health problem, as advanced disease has poor survivability due to the development of resistance in response to both standard and novel therapeutic interventions. Therapeutic resistance is a multifaceted problem involving the interplay of a number of biological mechanisms including genetic, signaling, and phenotypic alterations, compounded by the contributions of a tumor microenvironment that supports tumor growth, invasiveness, and metastasis. The androgen receptor (AR) is a primary regulator of prostate cell growth, response and maintenance, and the target of most standard PCa therapies designed to inhibit AR from interacting with androgens, its native ligands. As such, AR remains the main driver of therapeutic response in patients with metastatic castration-resistant prostate cancer (mCRPC). While androgen deprivation therapy (ADT), in combination with microtubule-targeting taxane chemotherapy, offers survival benefits in patients with mCRPC, therapeutic resistance invariably develops, leading to lethal disease. Understanding the mechanisms underlying resistance is critical to improving therapeutic outcomes and also to the development of biomarker signatures of predictive value. The interconversions between epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) navigate the prostate tumor therapeutic response, and provide a novel targeting platform in overcoming therapeutic resistance. Both microRNA (miRNA)- and long non-coding RNA (lncRNA)-mediated mechanisms have been associated with epigenetic changes in prostate cancer. This review discusses the current evidence-based knowledge of the role of the phenotypic transitions and novel molecular determinants (non-coding RNAs) as contributors to the emergence of therapeutic resistance and metastasis and their integrated predictive value in prostate cancer progression to advanced disease.

Exosomes as A Next-Generation Diagnostic and Therapeutic Tool in Prostate Cancer.

Extracellular vesicles (EVs) have brought great momentum to the non-invasive liquid biopsy procedure for the detection, characterization, and monitoring of cancer. Despite the common use of PSA (prostate-specific antigen) as a biomarker for prostate cancer, there is an unmet need for a more specific diagnostic tool to detect tumor progression and recurrence. Exosomes, which are EVs that are released from all cells, play a large role in physiology and pathology, including cancer. They are involved in intercellular communication, immune function, and they are present in every bodily fluid studied-making them an excellent window into how cells are operating. With liquid biopsy, EVs can be isolated and analyzed, enabling an insight into a potential therapeutic value, serving as a vehicle for drugs or nucleic acids that have anti-neoplastic effects. The current application of advanced technology also points to higher-sensitivity detection methods that are minimally invasive. In this review, we discuss the current understanding of the significance of exosomes in prostate cancer and the potential diagnostic value of these EVs in disease progression.

Androgens modify therapeutic response to cabazitaxel in models of advanced prostate cancer.

BACKGROUND: Disruption of the phenotypic landscape via epithelial-mesenchymal transition (EMT) enables prostate cancer cells to metastasize and acquire therapeutic resistance. Our previous studies demonstrated that cabazitaxel (CBZ) (second-generation Food and Drug Administration-approved taxane chemotherapy), used for the treatment of castration-resistant prostate cancer (CRPC), causes reversal of EMT to mesenchymal-epithelial transition (MET) and reduces expression of kinesin motor protein KIFC1 (HSET). The present study examined the effect of sequencing CBZ chemotherapy mediated MET on prostate tumor redifferentiation overcoming therapeutic resistance in models of advanced prostate cancer. METHODS: To examine the impact of androgens on the antitumor effect of CBZ, we used human prostate cancer cell lines with different sensitivity to androgens and CBZ, in vitro, and two human prostate cancer xenograft models in vivo. Tumor-bearing male mice (with either the androgen-sensitive LNCaP or the CRPC 22Rv1 xenografts) were treated with CBZ (3 mg/kg) alone, or in combination with castration-induced androgen-deprivation therapy (ADT) for 14 days. RESULTS: Cell viability assays indicate that the presence of 5α-dihydrotestosterone (1 nM) confers resistance to CBZ in vitro. CBZ treatment in vivo induced MET in LNCaP-derived tumors as shown by increased E-cadherin and decreased N-cadherin levels. Sequencing CBZ after ADT improves tumor response in androgen-sensitive LNCaP, but not in CRPC 22Rv1 xenografts. Mechanistic dissection revealed a novel association between the androgen receptor and HSET in prostate cancer cells that is inhibited by CBZ in an androgen-dependent manner. CONCLUSIONS: Our findings provide new insights into the phenotypic reprogramming of prostate cancer cells to resensitize tumors to CBZ action. This evidence is of translational significance in treatment sequencing (CBZ and ADT) towards improved therapeutic benefit in patients with lethal CRPC.

Staging Accuracy of Multiparametric Magnetic Resonance Imaging in Caucasian and African American Men Undergoing Radical Prostatectomy.

PURPOSE: We compared the performance of multiparametric magnetic resonance imaging for the prediction of extraprostatic extension in African American and Caucasian American men and evaluated racial disparities in pathological outcomes after radical prostatectomy. MATERIALS AND METHODS: We identified 975 patients who underwent radical prostatectomy with preoperative multiparametric magnetic resonance imaging between January 2013 and April 2019 at our institution. Multivariable logistic regression analysis was performed predicting pathological extraprostatic extension, high grade prostate cancer (final pathology GGG [Gleason Grade Group] 3 or greater) in the overall population and pathological upgrading (final pathology GGG 3 or greater) in patients with a diagnosis of GGG 1-2 prostate cancer. Adverse pathology was defined as pT3 and/or GGG 3 or greater. RESULTS: A total of 221 (23%) patients were African American. Preoperatively 594 (60.9%) were GGG 1-2 (low risk group) and 381 (39.1%) GGG 3 or greater (high risk group). In the low risk group rates of pathological extraprostatic extension (18% vs 12.8%, p=0.14), adverse pathology (18% vs 13.4%, p=0.2) or upgrading (9.4% vs 12.1%, p=0.4) were similar between races. Similarly, in the high risk group there was no difference in rates of pathological extraprostatic extension. On multivariable analysis multiparametric magnetic resonance imaging predicted the presence of extraprostatic extension (OR 1.80, 95% CI 1.29-2.50) and high grade prostate cancer (OR 1.82, 95% CI 1.25-2.67) on final pathology. Conversely, race did not predict the outcomes of interest (all values p >0.05). Multiparametric magnetic resonance imaging showed comparable sensitivity (22.22% vs 27.84%), specificity (89.2% vs 79.2%), positive predictive value (89.2% vs 83.4%) and negative predictive value (89.2% vs 83.4%) between African American and Caucasian America men, respectively. CONCLUSIONS: The accuracy of multiparametric magnetic resonance imaging in staging prostate cancer was similar in African American and Caucasian American patients and no difference was found between races in pathological outcomes after radical prostatectomy. These findings suggest that access to and use of advanced diagnostic tests may help mitigate prostate cancer racial disparities.

Integrated Therapeutic Targeting of the Prostate Tumor Microenvironment.

Prostate cancer is a common and deadly cancer among men. The heterogeneity that characterizes prostate tumors contributes to clinical challenges in the diagnosis, prognosis, and treatment of this malignancy. While localized prostate cancer can be treated with surgery or radiotherapy, metastatic disease to the lymph nodes and the bone requires aggressive treatment with androgen deprivation treatment (ADT). Unfortunately, this often eventually progresses to metastatic castration-resistant prostate cancer (mCRPC). Advanced prostate cancer treatment today involves 1st- and 2nd-line taxane chemotherapy and 2nd-generation antiandrogens. The process of epithelial mesenchymal transition (EMT), during which epithelial cells lose their adhesions and their polarity, is a critical contributor to prostate cancer metastasis. In this article, we aim to integrate the current understanding of mechanisms dictating the dynamics of phenotypic EMT, with apoptosis outcomes in prostate tumors in response to antiandrogen and taxane chemotherapy for the treatment of advanced disease. Novel insights into the signaling mechanisms that target the functional interface between apoptosis and EMT will be considered in the context of potential clinical markers of tumor prognosis, as well as for effective therapeutic targeting of α- and ß- adrenergic signaling (by novel and existing chemotherapeutic agents and antiandrogens). Interfering with EMT and apoptosis simultaneously toward eradicating the tumor mass is of major significance in combating the lethal disease and increasing patient survival.

TGF-ß receptor I inhibitor enhances response to enzalutamide in a pre-clinical model of advanced prostate cancer.

BACKGROUND: Prostate cancer progression is navigated by the androgen receptor (AR) and transforming-growth factor-ß (TGF-ß) signaling. We previously demonstrated that aberrant TGF-ß signaling accelerates prostate tumor progression in a transgenic mouse model of prostate cancer via effects on epithelial-mesenchymal transition (EMT), driving castration-resistant prostate cancer (CRPC). METHODS: This study examined the antitumor effect of the combination of TGF-ß receptor I (TßRI) inhibitor, galunisertib, and FDA-approved antiandrogen enzalutamide, in our pre-clinical model. Age-matched genotypically characterized DNTGFßRII male mice were treated with either galunisertib and enzalutamide, in combination or as single agents in three "mini"-trials and the effects on tumor growth, phenotypic EMT, and actin cytoskeleton were evaluated. RESULTS: Galunisertib in combination with enzalutamide significantly suppressed prostate tumor growth, by increasing apoptosis and decreasing cell proliferation of tumor cell populations compared to the inhibitor as a monotherapy (P < 0.05). The combination treatment dramatically reduced cofilin levels, actin cytoskeleton regulator, compared to single agents. Treatment with galunisertib targeted nuclear Smad4 protein (intracellular TGF-ß effector), but had no effect on nuclear AR. Consequential to TGF-ß inhibition there was an EMT reversion to mesenchymal-epithelial transition (MET) and re-differentiation of prostate tumors. Elevated intratumoral TGF-ß1 ligand, in response to galunisertib, was blocked by enzalutamide. CONCLUSION: Our results provide novel insights into the therapeutic value of targeting TGF-ß signaling to overcome resistance to enzalutamide in prostate cancer by phenotypic reprogramming of EMT towards tumor re-differentiation and cytoskeleton remodeling. This translational work is significant in sequencing TGF-ß blockade and antiandrogens to optimize therapeutic response in CRPC.

Cell death under epithelial-mesenchymal transition control in prostate cancer therapeutic response.

Prostate cancer is a widespread problem among men, with >160 000 new cases in 2017 alone. Androgen deprivation therapy is commonly used in prostate cancer treatment to block androgens required for cancer growth, but disease relapse after androgen deprivation therapy is both common and severe. Changes in androgen receptor signaling from androgen deprivation therapy have been linked to therapeutic resistance and tumor progression. Resistant cells can become reprogrammed to undergo epithelial-mesenchymal transition, a phenotypic switch from benign, epithelial cells to a mobile cell with mesenchymal traits. In these cells, attachment to their epithelial cell layer is no longer required for survival. Anoikis is a form of cell death that occurs when detachment from other cells and the basement membrane occurs. Epithelial cells have been shown to undergo epithelial-mesenchymal transition, avoid anoikis induction and progress to a metastatic phenotype. In prostate cancer progression to advanced disease, epithelial-mesenchymal transition induction (characterized by loss of epithelial cellular attachment protein E-cadherin) correlates with a higher Gleason score, tumor progression, increased metastasis and higher biochemical recurrence. The concept of interfacing epithelial-mesenchymal transition with anoikis in the tumor microenvironment landscape will be discussed here, with focus on the significance of the functional exchange between the two processes in therapeutic targeting of advanced disease. The current evidence on the impact of loss of cell-cell contact, acquisition of chemoresistance, immune escape and metastatic spread in advanced tumors in response to transforming growth factor-ß on prostate cancer metastasis will be also discussed. The signaling cross-talk between transforming growth factor-ß and androgen receptor signaling will be interrogated as a new therapeutic platform for the development of combination strategies to impair prostate cancer metastasis.

Profiling Prostate Cancer Therapeutic Resistance.

The major challenge in the treatment of patients with advanced lethal prostate cancer is therapeutic resistance to androgen-deprivation therapy (ADT) and chemotherapy. Overriding this resistance requires understanding of the driving mechanisms of the tumor microenvironment, not just the androgen receptor (AR)-signaling cascade, that facilitate therapeutic resistance in order to identify new drug targets. The tumor microenvironment enables key signaling pathways promoting cancer cell survival and invasion via resistance to anoikis. In particular, the process of epithelial-mesenchymal-transition (EMT), directed by transforming growth factor-ß (TGF-ß), confers stem cell properties and acquisition of a migratory and invasive phenotype via resistance to anoikis. Our lead agent DZ-50 may have a potentially high efficacy in advanced metastatic castration resistant prostate cancer (mCRPC) by eliciting an anoikis-driven therapeutic response. The plasticity of differentiated prostate tumor gland epithelium allows cells to de-differentiate into mesenchymal cells via EMT and re-differentiate via reversal to mesenchymal epithelial transition (MET) during tumor progression. A characteristic feature of EMT landscape is loss of E-cadherin, causing adherens junction breakdown, which circumvents anoikis, promoting metastasis and chemoresistance. The targetable interactions between androgens/AR and TGF-ß signaling are being pursued towards optimized therapeutic regimens for the treatment of mCRPC. In this review, we discuss the recent evidence on targeting the EMT-MET dynamic interconversions to overcome therapeutic resistance in patients with recurrent therapeutically resistant prostate cancer. Exploitation of the phenotypic landscape and metabolic changes that characterize the prostate tumor microenvironment in advanced prostate cancer and consequential impact in conferring treatment resistance are also considered in the context of biomarker discovery.

Predictive value of epithelial-mesenchymal-transition (EMT) signature and PARP-1 in prostate cancer radioresistance.

INTRODUCTION: Epithelial-mesenchymal-transition (EMT) has been previously identified as a contributor to prostate cancer progression to metastasis and therapeutic resistance to antiandrogens and radiotherapy. In this study we conducted a retrospective analysis to investigate the significance of radiation-induced EMT and consequential changes to the tumor microenvironment in biochemical recurrence and response to radiotherapy in prostate cancer patients. METHODS: Expression profiling and localization for EMT effectors, E-Cadherin, N-Cadherin, ß-catenin and Vimentin was assessed in human prostate tumor specimens pre- and post-radiotherapy and correlated with biochemical recurrence. In addition, immunoreactivity of the DNA repair enzyme, polymerase (PARP-1) and the cytoskeletal-remodeling regulator, cofilin was evaluated in prostate tumor specimens pre- and post-radiotherapy and correlated with pre-treatment prostate-specific antigen levels (PSA). RESULTS: Our findings identified that characteristic changes associated with the EMT phenotype and its reversal to mesenchymal-epithelial-transition (MET) within the tumor microenvironment correlate with biochemical recurrence and resistance to radiotherapy among prostate cancer patients. Moreover, elevated PARP-1 expression among the tumor cells undergoing EMT implicates that DNA repair mechanisms may potentially reverse the cytotoxic effects of radiotherapy-induced DNA breaks. CONCLUSIONS: Our results suggest that EMT programming effectors, integrated with the actin cytoskeleton regulator cofilin and mesenchymal PARP-1 expression profile provide a signature of potential predictive significance of therapeutic response to radiotherapy in a subset of prostate cancer patients.

Mechanisms of Therapeutic Resistance in Prostate Cancer.

Prostate cancer is the second leading cause of cancer deaths in the USA. The challenge in managing castration-resistant prostate cancer (CRPC) stems not from the lack of therapeutic options but from the limited duration of clinical and survival benefit offered by treatments in this setting due to primary and acquired resistance. The remarkable molecular heterogeneity and tumor adaptability in advanced prostate cancer necessitate optimization of such treatment strategies. While the future of CRPC management will involve newer targeted therapies in deliberately biomarker-selected patients, interventions using current approaches may exhibit improved clinical benefit if employed in the context of optimal sequencing and combinations. This review outlines our current understanding of mechanisms of therapeutic resistance in progression to and after the development of castration resistance, highlighting targetable and reversible mechanisms of resistance.

Epithelial-mesenchymal transition in prostatic disease.

A fully differentiated epithelium of the normal prostate gland allows epithelial cells to de-differentiate into mesenchymal-like derivatives via the process of epithelial-mesenchymal transition (EMT) and redifferentiate via the reverse process, mesenchymal-epithelial transition. This review discusses the phenotypic changes associated with EMT and its programming in the development of the two growth disorders of the aging prostate gland, benign prostatic hyperplasia and prostate adenocarcinoma. Considering the cellular heterogeneity that characterizes both conditions, identifying the transcriptional programming of the phenotypic framework defining EMT and its reverse process mesenchymal-epithelial transition in their pathological landscape will enable novel platforms for biomarker-driven therapeutics and their implementation in benign prostatic hyperplasia and prostate cancer.

PARP-1 regulates epithelial-mesenchymal transition (EMT) in prostate tumorigenesis.

Poly (ADP-ribose) polymerase (PARP) is involved in key cellular processes such as DNA replication and repair, gene transcription, cell proliferation and apoptosis. The role of PARP-1 in prostate cancer development and progression is not fully understood. The present study investigated the function of PARP-1 in prostate growth and tumorigenesis in vivo. Functional inactivation of PARP-1 by gene-targeted deletion led to a significant reduction in the prostate gland size in young PARP-1-/- mice (6 weeks) compared with wild-type (WT) littermates. To determine the effect of PARP-1 functional loss on prostate cancer onset, PARP-1-/- mice were crossed with the transgenic adenocarcinoma of the mouse prostate (TRAMP) mice. Pathological assessment of prostate tumors revealed that TRAMP+/-, PARP-1-/- mice exhibited higher grade prostate tumors compared with TRAMP+/- PARP-1+/+ (16-28 weeks) that was associated with a significantly increased proliferative index and decreased apoptosis among the epithelial cells in TRAMP+/- PARP-1-/- prostate tumors. Furthermore tumors harboring PARP-1 loss, exhibited a downregulation of nuclear androgen receptor. Impairing PARP-1 led to increased levels of transforming growth factor-ß (TGF-ß) and Smads that correlated with induction of epithelial-mesenchymal transition (EMT), as established by loss of E-cadherin and ß-catenin and upregulation of N-cadherin and ZEB-1. Our findings suggest that impaired PARP-1 function promotes prostate tumorigenesis in vivo via TGF-ß-induced EMT. Defining the EMT control by PARP-1 during prostate cancer progression is of translational significance for optimizing PARP-1 therapeutic targeting and predicting response in metastatic castration-resistant prostate cancer.