Impact of microRNAs on tumor-associated factors and signaling pathways: Mechanisms and perspectives

Numerous studies have linked microRNAs (miRNAs), small, single-stranded regulatory RNAs, to various human cancers. As integrators of post-transcriptional control, miRNAs contribute to tumor initiation, progression, therapeutic response, and resistance. Owing to their capacity to function as either tumor-suppressive or oncogenic factors, miRNAs have become the focus of research as potential targets for cancer diagnosis and treatment. Studies have shown that miRNAs can regulate tumor formation by modulating the extracellular environment, exosomes, and competing endogenous RNAs. They also play a significant role in regulating energy metabolism, cell cycle, cell growth and invasion, apoptosis and autophagy, and the proliferation of tumor cells. Therefore, miRNAs have potential as targets for cancer therapy and can serve as novel biomarkers. In this review, we systematically synthesize the signaling pathways that regulate tumor formation via miRNAs. We summarize and critically appraise different well-known signaling pathways, JAK/STAT3, Wnt/β-catenin, PI3K/AKT, TGF-β, and MAPK, to comprehensively understand the occurrence and mechanism of tumor development as modulated by miRNAs.