METTL3 promotes cell cycle progression via m6A/YTHDF1-dependent regulation of CDC25B translation.

The cell cycle machinery controls cell proliferation and the dysregulation of the cell cycle lies at the heart of carcinogenesis. Thus, exploring the unknown regulators involved in the cell cycle not only contribute to better understanding of cell proliferation but also provide substantial improvement to cancer therapy. In this study, we identified that the expression of methyltransferase METTL3 was upregulated in the M phase. Overexpression of METTL3 facilitated cell cycle progression, induced cell proliferation in vitro and enhanced tumorigenicity in vivo, while knockdown of METTL3 reversed these processes. METTL3 induced CDC25B mRNA m6A modification in the M phase, which accelerated the translation of CDC25B mRNA through YTHDF1-dependent m6A modification. Clinical data analysis showed that METTL3 and CDC25B were highly expressed in cervical cancer. Our work reveals that a new mechanism regulates cell cycle progression through the METTL3/m6A/CDC25B pathway, which provides insight into the critical roles of m6A methylation in the cell cycle.

Cyclophosphamide Induces the Ferroptosis of Tumor Cells Through Heme Oxygenase-1.

Ferroptosis has been implicated in the therapeutic responses of various types of tumors. Cyclophosphamide (CTX), one of the most successful antitumor agents, is widely used to treat both hematopoietic and solid tumors. In this study, we revealed the ferroptosis pathway targeted by CTX treatment in tumor cells and clarified its mechanisms. Cell viability was remarkably suppressed by CTX, accompanied by the accumulation of intracellular iron and reactive oxygen species (ROS), reduced glutathione levels, deformed mitochondria and a loss of the mitochondrial membrane potential. These effects were impeded by the ferroptosis inhibitors ferrostatin-1 (Fer1) and deferoxamine (DFO). Moreover, CTX treatment obviously upregulated nuclear factor E2 related factor 2 (NRF2) and heme oxygenase-1 (HMOX-1) expression. Additionally, the HMOX-1 inducer Hemin notably enhanced CTX-mediated tumor inhibition in vitro and in vivo through a mechanism that involved interfering with the ferroptosis process. Therefore, our findings indicated ferroptosis induction by CTX through the activation of the NRF2/HMOX-1 pathway, which might provide a potential strategy for tumor chemotherapy.

Schisandrin B attenuates renal fibrosis via miR-30e-mediated inhibition of EMT.

Tubulointerstitial fibrosis (TIF) is the main pathologic feature of end-stage renal disease. Epithelial-mesenchymal transition (EMT) of proximal tubular cells (PTCs) is one of the most significant features of TIF. MicroRNAs play critical roles during EMT in TIF. However, whether miRNAs can be used as therapeutic targets in TIF therapy remains undetermined. We found that miR-30e, a member of the miR-30 family, is deregulated in TGF-ß1-induced PTCs, TIF mice and human fibrotic kidney tissues. Moreover, transcription factors that induce EMT, such as snail, slug, and Zeb2, were direct targets of miR-30e. Using a cell-based miR-30e promoter luciferase reporter system, Schisandrin B (Sch B) was selected for the enhancement of miR-30e transcriptional activity. Our results indicate that Sch B can decrease the expression of snail, slug, and Zeb2, thereby attenuating the EMT of PTCs during TIF by upregulating miR-30e, both in vivo and in vitro. This study shows that miR-30e can serve as a therapeutic target in the treatment of patients with TIF and that Sch B may potentially be used in therapy against renal fibrosis.