No abstract

We aimed to study the role of METTL3 in renal cell carcinoma (RCC) carcinogenesis and development. Immunohistochemistry was performed in clinical tissue microarray. Expression level of METTL3 in RCC tissues and cell lines was evaluated by quantitative real-time PCR (qRT-PCR) and western blot. Then, the effects of METTL3 on proliferation, migration, invasion and cell cycle were studied in RCC cells. Additionally, in vivo study was carried out in nude mice. Negative METTL3 expression was associated with larger tumor size (P=0.010) and higher histological grade (P=0.021). Moreover, RCC patients with positive METTL3 expression had an obvious longer survival time (P=0.039). METTL3 mRNA and protein expression was lower in RCC samples compared with adjacent non-tumor samples, and lower in RCC cell lines (CAKI-1, CAKI-2 and ACHN) compared with HK-2. Afterwards, knockdown of METTL3 could obviously promote cell proliferation, migration and invasion function, and induce G0/G1 arrest. In contrast, up-regulation of METTL3 could inhibit such functions and reduce G0/G1 arrest. Additionally, up-regulation of METTL3 significantly suppressed tumor growth in vivo. Furthermore, significant changes in epithelial-to-mesenchymal transition (EMT) and PI3K-Akt-mTOR pathways were observed. Overall, our findings demonstrated that METTL3 might have a carcinostasis role in cell proliferation, migration, invasion function and cell cycle of RCC, indicating METTL3 may act as a novel marker for tumorigenesis, development and survival of RCC.

MicroRNAs have been implicated in regulating diverse cellular pathways. Emerging evidence indicates that miR-143 plays causal roles in cancer tumorigenesis as a tumor suppress gene; however, its role in prostate cancer tumorigenesis remains largely unknown. The aims of this study were to verify the effect of miR-143 on proliferation and migration abilities of prostate cancer cells. The expression level of miR-143 and its target gene KRAS were measured by realtime PCR and western blotting, respectively. Effects of miR-143 in cell proliferation, migration and chemosensitivity were evaluated by MTT assay, FACS cell cycle analysis, colony formation assay, and transwell migratory assay. Our results revealed an inverse correlation of expression between miR-143 and KRAS protein in prostate cancer samples (Pearson's correlation scatter plots: R = -0.707, P < 0.05). Moreover, over-expression of miR-143 in prostate cancer cells suppressed their proliferation and migration and increased their sensitivity to docetaxel by targeting EGFR/RAS/MAPK pathway. These findings suggest that miR-143 plays an important role in prostate cancer proliferation, migration and chemosensitivity by suppressing KRAS and subsequent inactivation of MAPK pathway, which provides a potential development of a new approach for the treatment of prostate cancer.