microRNA cluster MC-let-7a-1∼let-7d promotes autophagy and apoptosis of glioma cells by down-regulating STAT3

Background Accumulating evidence has highlighted the correlation between microRNAs (miRNAs) and the progression of glioma. However, the role of miR cluster MC-let-7a-1 similar to let-7d in glioma remains elusive. Thus, the current study aimed to investigate the effect of miR cluster MC-let-7a-1 similar to let-7d on glioma progression. Methods and Results Microarray data analysis provided data indicating the involvement of miR cluster MC-let-7a-1 similar to let-7d in glioma via STAT3. The expression of let-7a-1, let-7d, let-7f-1, and miR cluster MC-let-7a-1 similar to let-7d was diminished in the glioma tissues and the cell lines. Additionally, our results revealed that STAT3 was a target gene of let-7d, let-7a-1, and let-7f-1, which was further verified by the dual-luciferase reporter gene assay. Moreover, STAT3 expression was negatively mediated by let-7a-1, let-7d, and let-7f-1. Up-regulated miR cluster MC-let-7a-1 similar to let-7d or silenced STAT3 suppressed cell proliferation but accelerated cell apoptosis and autophagy. Moreover, restrained tumor growth was identified in the nude mice treated with miR cluster MC-let-7a-1 similar to let-7d mimics or STAT3 siRNA. Conclusion Taken together, the miR cluster MC-let-7a-1 similar to let-7d promotes glioma cell autophagy and apoptosis by repressing STAT3. The current study highlights the potential of the miR cluster MC-let-7a-1 similar to let-7d as biomarkers and promising treatment strategies for glioma.