Long noncoding RNA MEG3 regulates cell proliferation and apoptosis by disrupting microRNA-9-5p-mediated inhibition of NDRG1 in prostate cancer.

BACKGROUND: Long noncoding RNA MEG3 has been described to be involved in the regulation of gene expression and cancer progression. However, the role of lncMEG3 in prostate cancer (PCa) remains largely uncharted. METHODS: Differential expression of lncMEG3 was identified in PCa tissues using RNA-sequencing analysis. qRT-PCR was performed to examine the level of lncMEG3. Additionally, cellular fractionation and fluorescent in situ hybridization techniques were employed to determine the localization. Subsequently, functional assays were conducted to evaluate the impact of lncMEG3 and miR-9-5p on PCa proliferation and apoptosis in vitro and in vivo. The interaction between lncMEG3 and miR-9-5p was confirmed using RNA immunoprecipitation. Moreover, luciferase reporter assays were also utilized to investigate the relationship between miR-9-5p and NDRG1. RESULTS: We observed downregulation of lncMEG3 in PCa cells and tissues. Patients with lower levels of lncMEG3 had a higher likelihood of experiencing biochemical recurrence. Overexpression of lncMEG3 resulted in the inhibition of PCa cell proliferation and the promotion of apoptosis. Moreover, lncMEG3 is competitively bound to miR-9-5p, preventing its inhibitory effect on the target gene NDRG1. This ultimately led to the inhibition of PCa cell proliferation and the promotion of apoptosis. Furthermore, increasing lncMEG3 levels also demonstrated inhibitory effects on PCa proliferation and promotion of apoptosis in vivo. CONCLUSIONS: Our findings uncover a crucial role for lncMEG3 in inhibiting PCa proliferation and promoting apoptosis through disruption of miR-9-5p-mediated inhibition of NDRG1.

Combination with vorinostat enhances the antitumor activity of cisplatin in castration-resistant prostate cancer by inhibiting DNA damage repair pathway and detoxification of GSH.

BACKGROUND: Like DNA methylation, histone modifications are considered important processes for epigenetic alterations in gene function, and abnormally high expression of histone deacetylases (HDACs) plays a key role in many human diseases. In addition to regulating the acetylation levels of histone and non-histone proteins and gene transcription, HDAC inhibitors as antitumor drugs can also affect the DNA damage repair (DDR) pathway in tumor cells. Prostate cancer (PCa) is one of the most heritable malignancies in which DDR pathway defects can be detected in a considerable proportion of cases. Such defects are more prevalent in castration-resistant prostate cancer (CRPC) and are highly enriched in metastatic lesions. There is currently evidence that DDR pathway-deficient PCa is associated with high-risk biological behaviors and response sensitivity to platinum-based chemotherapy. Platinum-based drugs have been used in multiple clinical trials as monotherapy or in combination with other chemotherapeutic agents for the treatment of CRPC. METHODS: This study evaluated the combined anticancer effect of (cisplatin) CDDP and the HDAC inhibitors vorinostat (SAHA) on three androgen-dependent cell lines PC-3, DU-145, and C4-2B in vitro. The efficacy and safety of SAHA combined with CDDP in the treatment of CRPC were further verified through animal experiments. RESULTS: The combination of the two drugs increases cytotoxic effects by increasing DNA damage. Our results showed that the SAHA could not only reduce the expression of homologous recombinant repair proteins BRCA2, BRCA1, PARP1, and RAD51, but also decrease enzymes that Reduce the key enzymes of GSH biosynthesis, GSS and GCLC, and GSTP1 which can catalyze the binding of GSH to cisplatin. The intracellular GSH level also decreased with the increase of SAHA concentration, at the same time, the content of intracellular Pt element. CONCLUSION: The combination of CDDP and SAHA can produce synergistic anticancer effects in androgen-independent PCa cells in vitro and in vivo. Our results open up a new avenue for the effective treatment of CRPC. To optimize the chemotherapy regimen for patients with advanced PCa, it is necessary to further study the molecular mechanism of platinum drugs, HDAC inhibitors, and their combined action.

MiR-96-5p induced NDRG1 deficiency promotes prostate cancer migration and invasion through regulating the NF-κB signaling pathway.

OBJECTIVE: The N-myc downstream-regulated gene 1 (NDRG1) has been discovered as a significant gene in the progression of cancers. However, the regulatory mechanism of NDRG1 remained obscure in prostate cancer (PCa). METHODS: The miR-96-5p and NDRG1 expression levels were evaluated in PCa cell lines, prostate tissues, and validated public databases by real-time PCR, western blot analysis, and immunohistochemistry. The function of miR-96-5p and NDRG1 were investigated by wound healing and transwell assays in vitro, and mouse xenograft assay in vivo. The candidate pathway regulated by NDRG1 was conducted by the next-generation gene sequencing technique. Immunofluorescence and luciferase assay was used to detect the relation between miR-96-5p, NDRG1, and NF-κB pathway. RESULTS: Overexpressing NDRG1 suppresses the migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro, and inhibits metastasis in vivo. Moreover, miR-96-5p contributes to NDRG1 deficiency and promotes PCa cell migration and invasion. Furthermore, NDRG1 loss activates the NF-κB pathway, which stimulates p65 and IKBa phosphorylation and induces EMT in PCa. CONCLUSIONS: MiR-96-5p promotes the migration and invasion of PCa by targeting NDRG1 and regulating the NF-κB pathway.

CircGNG4 Promotes the Progression of Prostate Cancer by Sponging miR-223 to Enhance EYA3/c-myc Expression.

Patients diagnosed with prostate cancer often have a poor prognosis and limited treatment options, as the specific pathogenesis remains to be elucidated. Circular RNA (circRNA) is a type of non-coding RNA that interacts with microRNA (miRNA/miR) and transcription factors to regulate gene expression. However, little is known about specific circRNAs that serve roles in the pathogenesis of prostate cancer. Findings of the present study confirmed that circRNA G protein subunit γ 4 (circGNG4) was upregulated in prostate cancer tissues and cell lines. Knockdown of circGNG4 inhibited the malignant behavior of prostate cancer cells. Furthermore, bioinformatics were used to predict targeting interactions between circGNG4 or miR-223 and EYA transcriptional coactivator and phosphatase 3 (EYA3)/c-Myc mRNA. miR-223 inhibited the malignant behavior of prostate cancer cells, while EYA3/c-Myc had the opposite effect. circGNG4 enhanced the expression of EYA3/c-Myc by sponging miR-223 to promote the growth of prostate cancer tumors in vivo. In conclusion, the circGNG4/miR-223/EYA3/c-Myc regulatory pathway promoted the malignant progression of prostate cancer. The results of the present study may provide potential new targets for the diagnosis or treatment of prostate cancer.

Impact of positive surgical margin location and perineural invasion on biochemical recurrence in patients undergoing radical prostatectomy.

OBJECTIVE: To estimate the prognostic value of positive surgical margins (PSM) location and perineural invasion (PNI) for biochemical recurrence (BCR) in patients undergoing radical prostatectomy (RP). METHODS: All men with prostate cancer (PCa) who received RP in the second hospital of Tianjin Medical University from 2014 to 2018 were retrospectively identified. All patients met the following criteria: no neoadjuvant or adjuvant treatment, absence of lymph node invasion, or distant metastasis confirmed by surgery or imaging. Comparisons were made between cases with only apex positive (AM), isolated nonapical positive (OM), multiple positive (MM), and negative surgical margins (NSM). Patients were also subdivided according to the Gleason score and pathological tumor stage for analysis. RESULTS: A total of 416 patients available for analysis, of which 132 (31.7%) were PSM, 43 were AM, 37 were OM, and 52 were MM at a median follow-up of 27 months. The PNI was in 30.5% of patients. BCR occurred in 22.6% of patients during follow-up. Both AM and MM were noticed to be independent predictors of BCR with a hazard ratio of 4.192 (95% CI 2.185-8.042; p < 0.001) and 2.758 (95% CI 1.559-4.880; p < 0.001), respectively, when compared to NSM. Though the correlation was significant in univariate analysis, PNI was not an independent risk factor for BCR (p = 0.369). Subgroup analyses suggested that MM was not particularly predictive for BCR in the Gleason score < 8. The hole Cox regression model for the C-index was 0.843 CONCLUSIONS: PSM location was a significant independent predictor of BCR in PCa, especially in patients with AM or MM, while PNI is a non-independent risk factor. Compared with other locations, AM has a higher BCR risk.

Loss of miR-516a-3p mediates upregulation of ABCC5 in prostate cancer and drives its progression.

To gain a comprehensive understanding of whether ABCC5 can regulate prostate cancer (PCa) progression, we performed microarray data analyses and identified that ABCC5 was drastically increased in primary PCa relative to normal samples, metastatic PCa relative to primary PCa, and castration-resistant PCa relative to hormone naïve PCa, respectively. Multivariate Cox regression analysis suggested that ABCC5 overexpression in PCa was an independent prognostic factor for both poor biochemical recurrence-free and overall survival. We demonstrated that ABCC5 knockdown significantly inhibits PCa cell proliferation, migration, and invasion in vitro and suppresses tumor growth and metastasis in vivo. We also demonstrated that miR-516a-3p was significantly downregulated in PCa. We finally demonstrated that ABCC5 was a direct target of miR-516a-3p. miR-516a-3p overexpression can phenotypically copy ABCC5 knockdown-induced phenotypes, whereas forced expression of ABCC5 can drastically reverse the inhibitory effects of miR-516a-3p. miR-516a-3p may modulate the sensitivity of cancer cells to adriamycin and docetaxel by targeting ABCC5 with important implications in the design of new therapeutic agents. Taken together, our results indicated that loss of miR-516a-3p expression and thus uncontrolled ABCC5 upregulation might drive PCa progression and influence chemosensitivity.