Clinical implications of PTEN loss in prostate cancer

Genome-Based Classification and Therapy of Prostate Cancer

In the past decade, multi-national and multi-center efforts were launched to sequence prostate cancer genomes, transcriptomes, and epigenomes with the aim of discovering the molecular underpinnings of tumorigenesis, cancer progression, and therapy resistance. Multiple biological markers and pathways have been discovered to be tumor drivers, and a molecular classification of prostate cancer is emerging. Here, we highlight crucial findings of these genome-sequencing projects in localized and advanced disease. We recapitulate the utility and limitations of current clinical practices to diagnosis, prognosis, and therapy, and we provide examples of insights generated by the molecular profiling of tumors. Novel treatment concepts based on these molecular alterations are currently being addressed in clinical trials and will lead to an enhanced implementation of precision medicine strategies.

Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.

The 17-Gene Genomic Prostate Score Assay Predicts Outcome After Radical Prostatectomy Independent of PTEN Status

OBJECTIVE

To compare the ability of loss of phosphatase and tensin homolog (PTEN) and Genomic prostate score assay (GPS) in predicting the biochemical-recurrence (BCR) and clinical-recurrence (CR) after radical prostatectomy (RP) for clinically localized prostate cancer (PCa).

METHODS

Three hundred seventy seven patients with and without CR were retrospectively selected by stratified cohort sampling design from RP database. PTEN status (by immunohistochemistry [IHC] and fluorescence in situ hybridization [FISH]) and GPS results were determined for RP specimens. BCR was defined as Prostate Specific Antigen (PSA) ≥ 0.2 ng/mL or initiation of salvage therapy for a rising PSA. CR was defined as local recurrence and/or distant metastases.

RESULTS

Baseline mean age, PSA, and GPS score for the cohort were 61.1 years, 8 ng/dL, and 32.8. PTEN loss was noted in 38% patients by FISH and 25% by IHC. The concordance between FISH and IHC for PTEN loss was 66% (Kappa coefficient 0.278; P < .001). On univariable analysis, loss of PTEN by FISH or IHC was associated with BCR and CR (P < .05). However, after adjusting for GPS results, PTEN loss was not a significant predictor for CR or BCR (P > .1). The GPS result remained strongly associated with CR and BCR after adjusting for PTEN status (P < .001). PTEN status and GPS results only weakly correlated. GPS was widely distributed regardless of PTEN status indicating the biological heterogeneity of PCa even in PTEN-deficient cases.

CONCLUSION

GPS is a significant predictor of aggressive PCa, independent of PTEN status. After adjustment for GPS results, PTEN was not independently associated with recurrence for PCa.

Biphasic Alteration of Butyrylcholinesterase (BChE) During Prostate Cancer Development

Butyrylcholinesterase (BChE) is a plasma enzyme that hydrolyzes ghrelin and bioactive esters, suggesting a role in modulating metabolism. Serum BChE is reduced in cancer patients. In prostate cancer (PC), the down-regulation is associated with disease recurrence. Nonetheless, how BChE is expressed in PC and its impact on PC remain unclear. We report here the biphasic changes of BChE expression in PC. In vitro, BChE expression was decreased in more tumorigenic PC stem-like cells (PCSLCs), DU145, and PC3 cells compared to less tumorigenic non-stem PCs and LNCaP cells. On the other hand, BChE was expressed at a higher level in LNCaP cells than immortalized but non-tumorigenic prostate epithelial BPH-1 cells. In vivo, BChE expression was up-regulated in DU145 xenografts compared to LNCaP xenografts; DU145 cell-derived lung metastases displayed comparable levels of BChE as subcutaneous tumors. Furthermore, LNCaP xenografts produced in castrated mice exhibited a significant increase of BChE expression compared to xenografts generated in intact mice. In patients, BChE expression was down-regulated in PCs (n = 340) compared to prostate tissues (n = 86). In two independent PC populations MSKCC (n = 130) and TCGA Provisional (n = 490), BChE mRNA levels were reduced from World Health Organization grade group 1 (WHOGG 1) PCs to WHOGG 3 PCs, followed by a significant increase in WHOGG 5 PCs. The up-regulation was associated with a reduction in disease-free survival (P = .008). Collectively, we demonstrated for the first time a biphasic alteration of BChE, its down-regulation at early stage of PC and its up-regulation at advanced PC.

Correlation of Prostate Cancer CHD1 Status with Response to Androgen Deprivation Therapy: a Pilot Study

INTRODUCTION

CHD1 has been identified as a tumor suppressor gene in prostate cancer. Previous studies have shown strong associations between CHD1 deletion, prostate specific antigen [PSA] recurrence, and absence of ERG fusion. In this preliminary study we seek to find whether there is an independent correlation between CHD1 status and response to androgen deprivation therapy[ADT].

MATERIALS AND METHODS

We identified 11 patients with prostate cancer who underwent prostatectomy and received at least 7 months of ADT at our institution. They were divided into undetectable [PSA < 0.2 ng/mL; n = 8] and detectable [PSA > 0.2 ng/mL; n = 3] according to their serum PSA nadir after 7 months of ADT. Tissue microarray was generated from their formalin-fixed paraffin-embedded prostatectomy and involved lymph node tissues. Fluorescence in situ hybridization [FISH] analysis for CHD1 and immunohistochemical stains for PSA, AR, PTEN, ERG and SPINK1 were performed.

RESULTS

Our results showed heterogeneity of FISH and immunostains expressions in different foci of tumor. Status of CHD1, ERG, PTEN, or SPINK1 did not correlate with one another or with response to ADT.

CONCLUSIONS

Additional larger studies may be needed to further elucidate trends between these biomarkers and clinical outcomes in prostate cancer patients.

The role of protein tyrosine phosphatases in prostate cancer biology

Prostate cancer (PCa) is the most frequent malignancy in the male population of Western countries. Although earlier detection and more active surveillance have improved survival, it is still a challenge how to treat advanced cases. Since androgen receptor (AR) and AR-related signaling pathways are fundamental in the growth of normal and neoplastic prostate cells, targeting androgen synthesis or AR activity constitutes the basis of the current hormonal therapies in PCa. However, resistance to these treatments develops, both by AR-dependent and -independent mechanisms. Thus, alternative therapeutic approaches should be developed to target more efficiently advanced disease. Protein tyrosine phosphatases (PTPs) are direct regulators of the protein- and residue-specific phosphotyrosine (pTyr) content of cells, and dysregulation of the cellular Tyr phosphorylation/dephosphorylation balance is a major driving event in cancer, including PCa. Here, we review the current knowledge on the role of classical PTPs in the growth, differentiation, and survival of epithelial prostate cells, and their potential as important players and therapeutic targets for modulation in PCa.

Multiparametric Magnetic Resonance Imaging Features Identify Aggressive Prostate Cancer at the Phenotypic and Transcriptomic Level

PURPOSE

Multiparametric magnetic resonance imaging is a diagnostic tool for prostate cancer with limited data on prognostic use. We sought to determine whether multiparametric magnetic resonance could predict aggressive prostate cancer features.

MATERIALS AND METHODS

We retrospectively analyzed the records of 206 patients who underwent radical prostatectomy between 2013 and 2017. All patients had available RNA expression data on the final pathology specimen obtained from a location corresponding to a lesion location on multiparametric magnetic resonance imaging. The association between the PIRADS™ (Prostate Imaging Reporting and Data System) score and adverse pathology features were analyzed. We also performed differential transcriptomic analysis between the PIRADS groups. Factors associated with adverse pathology were analyzed using a multivariable logistic regression model.

RESULTS

Lesion size (p = 0.03), PIRADS score (p = 0.02) and extraprostatic extension (p = 0.01) associated significantly with the Decipher® score. Multivariable analysis showed that the PIRADS score (referent PIRADS 3, OR 8.1, 95% CI 1.2-57.5, p = 0.04), the Gleason Grade Group (referent 3, OR 5.6, 95% CI 1.5-21.1, p = 0.01) and prostate specific antigen (OR 1.103, 95% CI 1.011-1.203) were risk factors for adverse pathology findings. The difference between PIRADS 4 and 5 did not reach significance (OR 1.9, 95% CI 0.8-4.5, p = 0.12). However, the PI3K-AKT-mTOR, WNT-β and E2F signaling pathways were more active in PIRADS 5 than in PIRADS 4 cases.

CONCLUSIONS

The PIRADS score is associated with adverse pathology results, increased metastatic risk and differential genomic pathway activation.

Recent Advances in Prostate Cancer Treatment and Drug Discovery

Novel drugs, drug sequences and combinations have improved the outcome of prostate cancer in recent years. The latest approvals include abiraterone acetate, enzalutamide and apalutamide which target androgen receptor (AR) signaling, radium-223 dichloride for reduction of bone metastases, sipuleucel-T immunotherapy and taxane-based chemotherapy. Adding abiraterone acetate to androgen deprivation therapy (ADT) in order to achieve complete androgen blockade has proven highly beneficial for treatment of locally advanced prostate cancer and metastatic hormone-sensitive prostate cancer (mHSPC). Also, ADT together with docetaxel treatment showed significant benefit in mHSPC. Ongoing clinical trials for different subgroups of prostate cancer patients include the evaluation of the second-generation AR antagonists enzalutamide, apalutamide and darolutamide, of inhibitors of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway, of inhibitors of DNA damage response, of targeted alpha therapy and of prostate-specific membrane antigen (PSMA) targeting approaches. Advanced clinical studies with immune checkpoint inhibitors have shown limited benefits in prostate cancer and more trials are needed to demonstrate efficacy. The identification of improved, personalized treatments will be much supported by the major progress recently made in the molecular characterization of early- and late-stage prostate cancer using “omics” technologies. This has already led to novel classifications of prostate tumors based on gene expression profiles and mutation status, and should greatly help in the choice of novel targeted therapies best tailored to the needs of patients.