Tumor Suppressor Role and Clinical Significance of the FEV Gene in Prostate Cancer.

Background: In our previous research, we developed a 32-gene risk index model that may be utilized as a robust prognostic method for predicting prostate cancer (PCa) recurrence after surgery. Among the 32 genes, the Fifth Ewing Variant (FEV) gene was one of the top downregulated genes in relapsed PCa. However, current understanding of the FEV gene and its involvement in PCa is limited. Methods: FEV mRNA expression was analyzed and correlated to clinical outcomes in PCa patients who underwent prostatectomy at the Massachusetts General Hospital. Specimens from tissue microarray (TMA) including 102 prostate cancer patients were analysis for the expression of FEV. Meanwhile, FEV expression profiles were also assessed in PCa cell lines and in BPH-1 prostate epithelial cells using western blotting and quantitative reverse transcription-PCR (qRT-PCR). Furthermore, we transfected LNCaP and PC-3 cells with either an empty vector or full-length FEV gene and performed in vitro cell functional assays. The part FEV plays in tumor xenograft growth was also assessed in vivo. Results: Of the 191 patients included in this study base on the DASL dataset, 77 (40.3%) and 24 (13.6%), respectively, developed prostate-specific antigen (PSA) relapse and metastasis postradical prostatectomy. Significant FEV downregulation was observed in PCa patients showing PSA failure and metastasis. The protein expression of FEV was significantly negatively correlated with the Gleason score and pathological stage in prostate cancer tissues. Similarly, FEV expression significantly decreased in all PCa cell lines relative to BPH-1 (all P < 0.05). Functional assays revealed that FEV expression markedly inhibited PCa cell growth, migration, and invasion, which in turn significantly repressed the growth of tumor xenografts in vivo. Conclusion: The results of this study suggest an association between downregulated FEV expression and PSA relapse in PCa patients. In addition, FEV may act as a tumor suppressor in PCa.

Novel immune-related signature for risk stratification and prognosis in prostatic adenocarcinoma.

A substantial proportion of prostatic adenocarcinoma (PRAD) patients experience biochemical failure (BCF) after radical prostatectomy (RP). The immune microenvironment plays a vital role in carcinogenesis and the development of PRAD. This study aimed to identify a novel immune-related gene (IRG)-based signature for risk stratification and prognosis of BCF in PRAD. Weighted gene coexpression network analysis was carried out to identify a BCF-related module in a discovery cohort of patients who underwent RP at the Massachusetts General Hospital. The median follow-up time was 70.32 months. Random forest and multivariate stepwise Cox regression analyses were used to identify an IRG-based signature from the specific module. Risk plot analyses, Kaplan-Meier curves, receiver operating characteristic curves, univariate and multivariate Cox regression analyses, stratified analysis, and Harrell's concordance index were used to assess the prognostic value and predictive accuracy of the IRG-based signature in the internal discovery cohort; The Cancer Genome Atlas database was used as a validation cohort. Tumor immune estimation resource database analysis and CIBERSORT algorithm were used to assess the immunophenotype of PRAD. A novel IRG-based signature was identified from the specific module. Five IRGs (BUB1B, NDN, NID1, COL4A6, and FLRT2) were verified as components of the risk signature. The IRG-based signature showed good prognostic value and predictive accuracy in both the discovery and validation cohorts. Infiltrations of various immune cells were significantly different between low-risk and high-risk groups in PRAD. We identified a novel IRG-based signature that could function as an index for assessing tumor immune status and risk stratification in PRAD.

Correction to: MicroRNA-30d promotes angiogenesis and tumor growth via MYPT1/c-JUN/VEGFA pathway and predicts aggressive outcome in prostate cancer.

After publication of the article [1], the author reported that this article contained some errors.

TRIB1 induces macrophages to M2 phenotype by inhibiting IKB-zeta in prostate cancer.

Immunotherapy has made great breakthroughs in the field of cancer. However, the immunotherapeutic effect of prostate cancer is unsatisfactory. We found that the expression of TRIB1 was significantly correlated with the infiltration of CD163+ macrophages in prostate cancer. This study focused on the effects of TRIB1 on macrophage polarization in the immune microenvironment of prostate cancer. RNA sequencing analysis demonstrated that TRIB1 has significant effects on the regulation of the nuclear factor (NF)-κB signaling pathway and downstream cytokines. Flow cytometry and enzyme-linked immunosorbent assay were used to examine THP-1 cells cultured in conditioned medium from prostate cancer cells overexpressing TRIB1 and showed that overexpression of TRIB1 promoted the secretion of CXCL2 and interleukin (IL)8 by PC3 cells, which increased the secretion of IL12 by THP-1 cells as well as the expression of CD163 on THP-1 cells. IKB-zeta, regulated by TRIB1, was expressed in PC3 cells but was barely detectable in DU145 cells. The reductions in CXCL2 and IL8 by the inhibition of TRIB1 were rescued by the deletion of IKB-zeta. Here we showed that TRIB1 promoted the secretion of cytokines from prostate cancer cells and induced the differentiation of monocytes/macrophages into M2 macrophages.

Expression of PD-L1 in tumor-associated nerves correlates with reduced CD8+ tumor-associated lymphocytes and poor prognosis in prostate cancer.

To investigate immune profile consisting of stromal PD-L1 expression, inhibitory or non-T-cell inflamed tumor microenvironment that may predict response to anti-PD-L1/PD-1 immunotherapy in prostate cancer, we validated the specificity of a PD-L1 monoclonal antibody (E1L3N) and identified PD-L1 specific expression in prostatic stromal nerve cells. PD-L1 expression was analyzed in 73 primary prostate cancers and 7 castration-resistant prostate cancers (CRPC) by immunohistochemistry (IHC) and resulting data from primary prostate cancers were correlated with tumor-associated lymphocytes (TALs), clinicopathological characteristics and clinical outcome. PD-L1 was expressed in the tumor cells in only one primary prostate cancer case and none of the CRPC. However, PD-L1 was frequently observed in the nerve branches in the tumor-associated stroma (69 of 73 cases, 94.5%), supported by colocalization with axonal marker PGP9.5. FoxP3-, CD3- and CD8-positive T lymphocytes were observed in 74.6% (47/63), 98.4% (62/63) and 100% (61/61) of the cases, respectively. The density of PD-L1+ tumor-associated nerves (TANs) was inversely correlated with that of CD8+ TALs. Higher density of PD-L1+ TANs was significantly associated with biochemical recurrence (BCR) in Kaplan-Meier survival analysis (p = 0.016). In both univariate and multivariate Cox analysis, the density of PD-L1+ TANs was independently prognostic of BCR. In conclusion, PD-L1 expression is rare in prostate tumor cells but prevalent in TANs and negatively correlated with CD8+ TALs. Neuro-immunological interaction may be a contribution to immune-suppressive microenvironment. Combinatorial treatment regimen designs to neural PD-L1 and TALs should be warranted in future clinical application of anti-PD-L1/PD-1 immunotherapy in prostate cancer.

Downregulation of ARID4A and ARID4B promote tumor progression and directly regulated by microRNA-30d in patient with prostate cancer.

AT-rich interaction domain 4A (ARID4A) and AT-rich interaction domain 4B (ARID4B), which are both the AT-rich interaction domain (ARID) family, have been reported to be oncogene or tumor suppressor gene in various human malignances, but there is no involvement about their functions in prostate cancer (PCa). Our previous study has reported that microRNA-30d (miR-30d) expression can predicted poor clinical prognosis in PCa, however, the underlying mechanisms of miR-30d have not been fully described. The aim of our study is to investigate the expression relevance between miR-30d and ARID4A or ARID4B, and examine the clinical significance and biological function of ARID4A and AIRD4B in PCa. In this study, both ARID4A and ARID4B were identified as the target genes of miR-30d. In addition, the mRNA expression of miR-30d in PCa tissues were significantly negative correlated with ARID4A (Pearson correlation coefficient = -0.313, P = 0.001) and ARID4B (Pearson correlation coefficient = -0.349, P < 0.001), while there was a positive correlation between ARID4A and ARID4B (Pearson correlation coefficient = 0.865, P < 0.001). Moreover, both ARID4A and ARID4B were significantly downregulated in PCa tissues with high Gleason scores (P = 0.005, P = 0.033), PSA failure (P = 0.012, P = 0.05) and short biochemical recurrent-free survival (P = 0.033, P = 0.031). Furthermore, the knockout expression of ARID4A and ARID4B promoted PCa cell proliferation, migration and invasion in vitro. In conclusion, our results indicated that ARID4A and ARID4B may serve as tumor suppressor in PCa progression, suggesting that they might be the potential therapeutic targets in prostate cancer.

Decreased expression of TCF12 contributes to progression and predicts biochemical recurrence in patients with prostate cancer.

As a member of helix-loop-helix protein family, transcription factor 12 functions as either an oncogene or a tumor suppressor in various human cancers. However, there are no reports on its involvement in prostate cancer. To investigate clinical relevance of transcription factor 12 in prostate cancer and to evaluate its roles in malignant phenotypes of this cancer in vitro and in vivo, we here examined expression patterns of transcription factor 12 protein in 50 prostate cancer tissue specimens by immunohistochemistry. Then, associations of transcription factor 12 expression with various clinicopathological characteristics and patients' prognosis of prostate cancer were evaluated. Its involvements in cancer cell proliferation, migration, invasion, and tumor growth were determined by in vitro and in vivo experiments. As a result, the positive immunostaining of transcription factor 12 protein was localized in cytoplasm and/or nucleus of prostate cancer cells. Its expression levels were decreased with prostate cancer Gleason score increased. Statistically, the decreased expression of transcription factor 12 protein more frequently occurred in prostate cancer patients with high Gleason score, positive metastasis, prostate-specific antigen failure, and short biochemical recurrence-free survival (all p < 0.05). Importantly, multivariate analysis showed that the status of transcription factor 12 expression was an independent predictor of biochemical recurrence-free survival in prostate cancer. Functionally, enforced expression of transcription factor 12 suppressed cell proliferation, migration, and invasion in vitro and inhibited tumor growth in vivo. In conclusion, transcription factor 12 protein may be a novel molecule which plays a critical role in prostate cancer progression and patients' prognosis, suggesting it might be a promising therapeutic target for prostate cancer therapy.

MicroRNA-30d promotes angiogenesis and tumor growth via MYPT1/c-JUN/VEGFA pathway and predicts aggressive outcome in prostate cancer.

BACKGROUND: Even though aberrant expression of microRNA (miR)-30d has been reported in prostate cancer (PCa), its associations with cancer progression remain contradictory. The aim of this study was to investigate clinical significance, biological functions and underlying mechanisms of miR-30d deregulation in PCa. METHODS: Involvement of miR-30d deregulation in malignant phenotypes of PCa was demonstrated by clinical sample evaluation, and in vitro and in vivo experiments. The mechanisms underlying its regulatory effect on tumor angiogenesis were determined. RESULTS: miR-30d over-expression was observed in both PCa cells and clinical specimens. High-miR-30d was distinctly associated with high pre-operative PSA and Gleason score, advanced clinical and pathological stages, positive metastasis and biochemical recurrence (BCR), and reduced overall survival of PCa patients. Through gain- and loss-of-function experiments, we found that miR-30d promoted PCa cell proliferation, migration, invasion, and capillary tube formation of endothelial cells, as well as in vivo tumor growth and angiogenesis in a mouse model. Simulation of myosin phosphatase targeting subunit 1 (MYPT1), acting as a direct target of miR-30d, antagonized the effects induced by miR-30d up-regulation in PCa cells. Notably, miR-30d/MYPT1 combination was identified as an independent factor to predict BCR of PCa patients. Furthermore, miR-30d exerted its pro-angiogenesis function, at least in part, by inhibiting MYPT1, which in turn, increased phosphorylation levels of c-JUN and activated VEGFA-induced signaling cascade in endothelial cells. CONCLUSIONS: miR-30d and/or its target gene MYPT1 may serve as novel prognostic markers of PCa. miR-30d promotes tumor angiogenesis of PCa through MYPT1/c-JUN/VEGFA pathway.

BCL9, a coactivator for Wnt/ß-catenin transcription, is targeted by miR-30c and is associated with prostate cancer progression.

B-cell lymphoma 9 (BCL9), a component of aberrantly activated Wnt signaling, is an important contributing factor to tumor progression. Our previous data indicated that downregulation of the tumor suppressor microRNA-30c (miR-30c) was a frequent pathogenetic event in prostate cancer (PCa). However, a functional link between miR-30c and BCL9/Wnt signaling, and their clinical and pathological significance in PCa, have not been well established. The present study demonstrated that miR-30c serves as a key negative regulator targeting BCL9 transcription in PCa cells. Ectopic expression of miR-30c was associated with reduced expression of Wnt pathway downstream targets, including c-Myc, cluster of differentiation 44 and sex determining region Y-box 9 in DU145 human PCa cells. Examination of clinical prostate specimens revealed higher levels of BCL9 expression in PCa compared with that in benign prostate tissues. After substantiating this finding by patient sample analysis, BCL9 expression or activity was observed to be closely correlated with PCa biochemical recurrence (BCR) and disease progression, whereas it was inversely associated with miR-30c. Furthermore, overexpression of BCL9 in PCa acted cooperatively with miR-30c low expression to predict earlier BCR in PCa. These findings indicate that inhibition of BCL9/Wnt signaling by miR-30c is important in the progression of PCa. Furthermore, the combined analysis of miR-30c and BCL9 may be valuable tool for prediction of BCR in PCa patients following radical prostatectomy.