Background: N6-methyladenosine (m⁶A) is the most abundant modification in mRNA of humans. Emerging evidence has supported the fact that m⁶A is comprehensively involved in various diseases especially cancers. As a crucial reader, YTHDF2 usually mediates the degradation of m⁶A-modified mRNAs in m⁶A-dependent way. However, the function and mechanisms of m⁶A especially YTHDF2 in prostate cancer (PCa) still remain elusive. Methods: To investigate the functions and mechanisms of YTHDF2 in PCa, in vitro, in vivo biofunctional assays and epigenetics experiments were performed. Endogenous expression silencing of YTHDF2 and METTL3 was established with lentivirus-based shRNA technique. Colony formation, flow cytometry and trans-well assays were performed for cell function identifications. Subcutaneous xenografts and metastatic mice models were combined with in vivo imaging system to investigate the phenotypes when knocking down YTHDF2 and METTL3. m⁶A RNA immunoprecipitation (MeRIP) sequencing, mRNA sequencing, RIP-RT-qPCR and bioinformatics analysis were mainly used to screen and validate the direct common targets of YTHDF2 and METTL3. In addition, TCGA database was also used to analyze the expression pattern of YTHDF2, METTL3 and the common target LHPP in PCa, and their correlation with clinical prognosis. Results: The upregulated YTHDF2 and METTL3 in PCa predicted a worse overall survival rate. Knocking down YTHDF2 or METTL3 markedly inhibited the proliferation and migration of PCa in vivo and in vitro. LHPP and NKX3–1 were identified as the direct targets of both YTHDF2 and METTL3. YTHDF2 directly bound to the m⁶A modification sites of LHPP and NKX3–1 to mediate the mRNA degradation. Knock-down of YTHDF2 or METTL3 significantly induced the expression of LHPP and NKX3–1 at both mRNA and protein level with inhibited phosphorylated AKT. Overexpression of LHPP and NKX3–1 presented the consistent phenotypes and AKT phosphorylation inhibition with knock-down of YTHDF2 or METTL3. Phosphorylated AKT was consequently confirmed as the downstream of METTL3/YTHDF2/LHPP/NKX3–1 to induce tumor proliferation and migration. Conclusion: We propose a novel regulatory mechanism in which YTHDF2 mediates the mRNA degradation of the tumor suppressors LHPP and NKX3–1 in m⁶A-dependent way to regulate AKT phosphorylation-induced tumor progression in prostate cancer. We hope our findings may provide new concepts of PCa biology.

Because conventional prostate biopsy has some limitations, optimal variations of prostate biopsy strategies have emerged to improve the diagnosis rate of prostate cancer. We conducted the systematic review to compare the diagnosis rate and complications of transperineal versus transrectal prostate biopsy. We searched for online publications published through June 27, 2018, in PubMed, Scopus, Web of Science, and Chinese National Knowledge Infrastructure databases. The relative risk and 95% confidence interval were utilized to appraise the diagnosis and complication rate. The condensed relative risk of 11 included studies indicated that transperineal prostate biopsy has the same diagnosis accuracy of transrectal prostate biopsy; however, a significantly lower risk of fever and rectal bleeding was reported for transperineal prostate biopsy. No clue of publication bias could be identified. To conclude, this review indicated that transperineal and transrectal prostate biopsy have the same diagnosis accuracy, but the transperineal approach has a lower risk of fever and rectal bleeding. More studies are warranted to confirm these findings and discover a more effective diagnosis method for prostate cancer.

N6‐Methyladenosine (m ⁶ A) modification, the most prevalent modification of eukaryotic messenger RNA (mRNA), is involved in the progression of various tumours. However, the specific role of m ⁶ A in bladder cancer (BCa) is still poorly understood. In this study, we demonstrated the tumour‐promoting function and specific regulatory mechanism of m ⁶ A axis, consisting of the core ‘writer’ protein METTL3 and the major reader protein YTHDF2. Depletion of METTL3 impaired cancer proliferation and cancer metastasis in vitro and in vivo. Through transcriptome sequencing, m ⁶ A methylated RNA immunoprecipitation (MeRIP) and RIP, we determined that the METTL3/YTHDF2 m ⁶ A axis directly degraded the mRNAs of the tumour suppressors SETD7 and KLF4, contributing to the progression of BCa. In addition, overexpression of SETD7 and KLF4 revealed a phenotype consistent with that induced by depletion of the m ⁶ A axis. Thus, our findings on the METTL3/YTHDF2/SETD7/KLF4 m ⁶ A axis provide the insight into the underlying mechanism of carcinogenesis and highlight potential therapeutic targets for BCa.

N6-methyladenosine (m⁶A) is a key area in Epigenetics and has been increasingly focused these years. In the m⁶A process, readers recognize the m⁶A modification on mRNAs or noncoding RNAs and mediate different downstream events. Emerging studies have shown that YTHDC1, an important m⁶A reader, plays a key role in many biological functions and disease progression, especially cancers. Here we summarized the current mechanisms of YTHDC1 in biological functions and diseases and offered guidance for future researches to provide potential strategy for clinical diagnose and therapy.

As the most abundant and reversible RNA modification in eukaryotic cells, m⁶A triggers a new layer of epi‐transcription. M⁶A modification occurs through a methylation process modified by “writers” complexes, reversed by “erasers”, and exerts its role depending on various “readers”. Emerging evidence shows that there is a strong association between m⁶A and human diseases, especially cancers. Herein, we review bi‐aspects of m⁶A in regulating cancers mediated by the m⁶A‐associated proteins, which exert vital and specific roles in the development of various cancers. Generally, the m⁶A modification performs promotion or inhibition functions (dual role) in tumorigenesis and progression of various cancers, which suggests a new concept in cancer regulations. In addition, m⁶A‐targeted therapies including competitive antagonists of m⁶A‐associated proteins may provide a new tumour intervention in the future.

Emerging evidence has elucidated that microRNAs (miRNAs) transcribed from miRNA cluster at DLK‐DIO3 imprinted domain are involved in various cancers. However, as one member of this cluster, the underlying mechanisms and functions of miR‐381‐3p in bladder cancer (BCa) still remains elusive. Here we demonstrate that the hypermethylated status of upstream maternally expressed gene 3 divergent methylation region reduces the expression of miR‐381‐3p in BCa by bisulfite‐sequencing PCR. In vitro and in vivo experiments indicate that overexpression of miR‐381‐3p significantly inhibits cell proliferation via inducing G ₁ phase arrest and migration via down‐regulating MET and CCNA2 induced EMT progression. CDK6/CCNA2/MET are all identified as the direct targets of miR‐381‐3p by bioinformatics analysis and dual‐luciferase reporter assay. Furthermore, inhibition of CCNA2 mediated by miR‐381‐3p as the crucial biregulator not only participates in the proliferation regulation with CDK6 in cell cycle but also modulates the EMT progression via ROCK/AKT/β‐catenin/SNAIL pathway, which establishes an EMT circuit combined with miR‐381‐3p/MET/AKT/GSK‐3β/SNAIL pathway, and SNAIL is the last confocal target to induce EMT progression. To conclude, we propose 2 novel regulatory circuits mediated by miR‐381‐3p in BCa, which may assist in the development of more effective therapies against BCa in the future.—Li, J., Ying, Y., Xie, H., Jin, K., Yan, H., Wang, S., Xu, M., Xu, X., Wang, X., Yang, K., Zheng, X., Xie, L. Dual regulatory role of CCNA2 in modulating CDK6 and MET‐mediated cell‐cycle pathway and EMT progression is blocked by miR‐381‐3p in bladder cancer. FASEB J. 33, 1374–1388 (2019). www.fasebj.org