Long noncoding RNA LEF1-AS1 silencing suppresses the initiation and development of prostate cancer by acting as a molecular sponge of miR-330-5p via LEF1 repression.

Prostate cancer (PCa) is one of the major cancers affecting males with high mortality around the world. Recent studies have found that some long noncoding RNAs play a critical part in the cellular processes of PCa. In our study, aberrant expressed lymphoid enhancer-binding factor-1 antisense RNA 1 (LEF1-AS1), microRNA-330-5p (miR-330-5p), and lymphoid enhancer-binding factor-1 (LEF1) were screened out from a microarray database, the role of the novel noncoding RNA regulatory circuitry in the initiation and development of PCa was investigated. LEF1-AS1 and LEF1 were highly expressed while miR-330-5p was poorly expressed in PCa. Following that, the PCa PC-3 cell line was adopted for subsequently experiments, in which the expression of LEF1-AS1 and miR-330-5p was subsequently altered by means of exogenous transfection. After that, the effects of up- or downregulation of LEF1-AS1 and miR-330-5p on epithelial-mesenchymal transition (EMT) and the cell ability for proliferation, invasion, migration in vitro, and tumorigenesis and lymph node metastasis (LNM) in vivo were evaluated. RNA crosstalk revealed that LEF1-AS1 bound to miR-330-5p and LEF1 was the target gene of miR-330-5p. Silenced LEF1-AS1 or elevated miR-330-5p exhibited inhibited EMT processes, reduced ability of proliferation, invasion and migration, coupling with decreased tumorigenesis and LNM in nude mice. The key findings of this study collectively propose downregulation of LEF1-AS1 competing with miR-330-5p to inhibit EMT, invasion and migration of PCa by LEF1 repression.

The antitumor effect of the novel cancer-specific adenovirus Ad-VEGFR on bladder cancer in vitro and in vivo.

Bladder cancer is one of the most common cancers. Approaches that block tumor angiogenesis are a new therapeutic strategy for locally advanced or metastatic BC. VEGF/VEGFR signaling has been obviously and negatively correlated with the progression and invasion of cancer. In this study, we constructed the recombinant adenovirus vAd-VEGFR-3 to investigate its antitumor effector in vitro/vivo. First, we used the recombinant adenovirus vAd-VEGFR-3 to infect bladder cancer cells and then collected the cell culture supernatant to treat human umbilical vein endothelial cells (HUVECs). The proliferation, migration and apoptosis of HUVECs were respectively detected by MTT, transwell and Annexin V-FITC/PI double staining. In addition, mouse bladder mucosa was injured by trypsin, and the orthotopic transplantation model of human bladder cancer was successfully constructed to clarify the anti-tumor effect of Ad-VEGFR in vivo. The results showed that Ad-VEGFR could inhibit the cancer's proliferation and migration, while promoting the apoptosis of HUVECs in vitro. Moreover, Ad-VEGFR could significantly promote the apoptosis of bladder cancer cells and then prevent tumor growth in vivo. In addition, it also down-regulated the expression levels of CD31, an endothelial cell marker which is closely related to the angiogenesis. Taken together, it suggests that the infection of adenovirus-carrying VEGFR in bladder cancer cells may inhibit blood vessel formation and prevent tumor progression.

miR-361-5p modulates metabolism and autophagy via the Sp1-mediated regulation of PKM2 in prostate cancer.

Prostate cancer (PCa) is a leading cause of death among men. The dysregulation of metabolism and autophagy contributes to the progression of PCa. The transcription factor specificity protein 1 (Sp1) is implicated in the regulation of metabolism and autophagy. We confirmed that Sp1 is overexpressed in castration-resistant prostate cancer (CRPC) cells. However, the roles of Sp1 in PCa metabolism and autophagy remain unclear. Thus, in the present study, we retrieved the GSE35988 dataset from Gene Expression Omnibus (GEO) database to reinvestigate Sp1 expression and its role in PCa.We found that in PCa, Sp1 knockdown significantly inhibited cell growth, aerobic glycolysis, and hypoxia-induced autophagy, which were accompanied by an increased G1 cell cycle arrest. Pearson correlation indicated that pyruvate kinase isoenzyme type M2 (PKM2) is positively correlated with Sp1 expression. Western blot analysis demonstrated that Sp1 directly regulates PKM2; therefore, Sp1 modulates metabolism and autophagy in CRPC. Western blot analysis and luciferase reporter assay also indicated that the tumor suppressor miR-361-5p inversely regulates Sp1 by directly targeting the binding site in the 3'UTR of Sp1. miR-361-5p overexpression presented effects that are similar to Sp1 depletion in PCa. In summary, this study is the first to demonstrate that miR-361-5p suppresses the Sp1/PKM2 axis, consequently affecting the progression of PCa and the metabolism and autophagy of PCa cells. Therefore, targeting the miR-361-5p/Sp1/PKM2 pathway has considerable clinical significance in preventing the malignant progression of PCa.

BTG1 potentiates apoptosis and suppresses proliferation in renal cell carcinoma by interacting with PRMT1.

B-cell translocation gene 1 (BTG1) is a member of the BTG/transducer of Erb family. BTG1 regulates cell cycle progression, inhibits proliferation, promotes apoptosis and stimulates cellular differentiation in multiple cell types. However, the functions of BTG1 in renal cell carcinoma (RCC) remain unclear. Therefore, the present study investigated the role of BTG1 in RCC tissue samples and 786-O RCC cells. RCC tissues and cells exhibited significantly weaker BTG1 protein and mRNA expression compared with para-carcinoma control tissues (P<0.05). Upregulated BTG1 expression induced significant G0/G1 cell cycle arrest, apoptosis and inhibition of cell proliferation in 786-O cells (P<0.05). Furthermore, BTG1 interacted with protein arginine N-methyltransferase 1 (PRMT1), and blocking the action of PRMT1 in 786-O cells resulted in inhibition of BTG1 function. These findings indicate that BTG1 may inhibit cell growth and promote apoptosis by interacting with PRMT1 in RCC; the identification of this mechanism may aid in the production of novel therapies for RCC.

Autoregulatory feedback loop of EZH2/miR-200c/E2F3 as a driving force for prostate cancer development.

The histone methyltransferase enhancer of zeste homolog 2 (EZH2) has recently attracted considerable attention because of its dysregulation in prostate cancer (PCa) and its important function in PCa development. To date, little is known about the underlying cellular function and regulatory networks of EZH2 in PCa. This study aims to determine whether or not the autoregulatory feedback loop of EZH2/miR-200c/E2F3 serves key functions in PCa development. Bioinformatics and integrative analytical approaches were employed to identify the relationships of EZH2 to specific cancer-related gene sets. Results indicated that the enrichment of gene sets about cell cycle progression was associated with EZH2 expression. The depletion of EZH2 in cell experiments inhibited PCa cell growth and blocked cell cycle accompanying the downregulation of E2F3 expression. Furthermore, miR-200c served as an important mediator between EZH2 and E2F3. Compared with scrambled control cells, sh-EZH2 cells showed lower H3K27me3 expression and higher miR-200c expression. Western blot and luciferase reporter assays showed that miR-200c inversely modulated E2F3 by directly targeting the binding site within 3'UTR. Moreover, decreased miR-200c expression largely abrogated the effect of sh-EZH2 on E2F3 expression and E2F3-induced cell cycle progression. EZH2 was positively regulated by E2F3 at the transcriptional level. Immunohistochemistry and in situ hybridization revealed a significant correlation among EZH2, miR-200c, and E2F3 expression in human PCa tissues. In conclusion, the autoregulatory feedback loop of EZH2/miR-200c/E2F3 served an important function in PCa development. Targeting this aberrantly activated feedback loop may provide a new therapeutic strategy against PCa.

Loss of SNAIL inhibits cellular growth and metabolism through the miR-128-mediated RPS6KB1/HIF-1α/PKM2 signaling pathway in prostate cancer cells.

SNAIL is a promising target for the treatment of cancer because it is known to promote epithelial-mesenchymal transition. Recent studies suggest that SNAIL also takes part in metabolic reprogramming and chemotherapy resistance in some cancers. In prostate cancer (PCa), SNAIL has been proved to be required for hypoxia-induced invasion and as a potential marker for predicting the recurrence. However, the role of SNAIL in PCa aberrant metabolism is poorly understood. In this study, we identified that SNAIL regulated cellular growth and energy metabolism through the miR-128-mediated ribosomal protein S6 kinase 1 (RPS6KB1)/HIF-1α/PKM2 signaling pathway which played a key role in the reprogramming of cancer metabolism. Using quantitative RT-PCR (qRT-PCR), we found that SNAIL expression was elevated in castration-resistant prostate cancer tissues compared with androgen-dependent prostate cancer tissues and nontumorous tissues. Depletion of SNAIL increased miR-128 expression levels, inhibited cell growth, reduced glucose consumption and lactate production, and repressed the expression of RPS6KB1, HIF-1α, and PKM2 in PCa cells. Luciferase reporter assays showed the SNAIL regulated miR-128 expression at the transcriptional level and miR-128 modulated RPS6KB1 expression at the translational level. Furthermore, down-expression of miR-128 partially restored the effect of si-SNAIL on the suppression of cellular growth, metabolism, and RPS6KB1/HIF-1α/PKM2 signaling pathway. To our knowledge, it is the first time to demonstrate that SNAIL/miR-128/RPS6KB1 pathway plays a critical role in the progression of PCa.

MiR-361-5p acts as a tumor suppressor in prostate cancer by targeting signal transducer and activator of transcription-6(STAT6).

Castration-resistant prostate cancer (CRPC), whose pathogenesis is known to be regulated by microRNAs (miRNAs), has a poor prognosis. In our present study, we found that the expression of miR-361-5p in CRPC was lower than in androgen-dependent prostate cancer (ADPC), indicating that miR-361-5p may play an important role in the progression of ADPC to CRPC. The role of miR-361-5p in prostate cancer (PCa) has not been evaluated until date. Our findings suggest that miR-361-5p is a suppressor in CRPC. Signal transducer and activator of transcription-6 (STAT6), a direct target of miR-361-5p, enhances the expression of B-cell lymphoma-extra large (Bcl-xL), while miR-361-5p inhibits its expression through STAT6. Therefore, miR-361-5p has great clinical significance in preventing the malignant progression of PCa.

Long non-coding RNAs and prostate cancer.

A new class of transcripts, long non-coding RNAs (IncRNAs), has been recently found to be pervasively transcribed in the genome. These mRNA-like molecules, which lack significant protein-coding capacity, once thought to be a part of the dark matter, now have been implicated in a wide range of biological functions through diverse and as yet poorly understood molecular mechanisms. Multiple facets of evidence increasingly link mutations and dysregulations of IncRNAs to prostate cancer (PCA). Despite some recent insights into how IncRNAs function in such diverse cellular processes as regulation of gene expression and assembly of cellular structures, by and large, the key questions regarding IncRNA mechanisms remain to be answered. In this review, we analysis recent advances in understanding the biological functions of IncRNAs especially in PCA and propose avenues of investigation that may lead to fundamental new insights into their functions and mechanisms of action. Finally, as numerous IncRNAs are dysregulated and disorders in PCA, we also discuss potential roles for these molecules in PCA and hope that can be used in clinic by nanotechnology.

The complex roles of microRNAs in the metastasis of renal cell carcinoma.

Renal cell carcinoma (RCC) accounts for approximately 3% of cancers in adults as well as the most common neoplasm of the adult kidney with the highest mortality rate at over 40%. Metastasis is the most significant process affecting the clinical management of RCC patients. It occurs in multiple sequential steps. However, the molecular pathways underlying each step still remain obscure. Recent researches have shown that microRNAs (miRNAs) function as regulators in metastasis of RCC. In this article, we review the role of miRNAs in metastasis of RCC, including: specific miRNA signatures of metastatic RCC, metastasis-associated targets and pathways of miRNAs in RCC, miRNAs participate in epithelial-mesenchymal transition (EMT), miRNA DNA methylation signature in RCC metastasis and so on. MiRNAs are potential to serve as powerful biomarkers of RCC metastasis and novel therapeutic targets in RCC treatment.