miR-140-5p induces cell apoptosis and decreases Warburg effect in chronic myeloid leukemia by targeting SIX1.

microRNAs (miRNA), as tumor suppressors or oncogenes, are involved in modulating cancer cell behavior, including cell proliferation and apoptosis. The miR-140-5p acts as a tumor suppressor in several tumors, but the role of miR-140-5p in chronic myeloid leukemia (CML) remains unclear. Here, we investigated the suppression of miR-140-5p in CML patients and CML cell lines using quantitative PCR (qPCR) and fluorescence hybridization (FISH). Overexpression miR-140-5p in CML cells significantly inhibited cell proliferation as revealed by the CCK-8 assay and promoted cell apoptosis as revealed by flow cytometry. Moreover, the sine oculis homeobox 1 (SIX1) gene had been confirmed as a direct target of miR-140-5p using bioinformatics analysis and luciferase reporter assays. Overexpression of miR-140-5p decreased the SIX1 protein level in CML cells. SIX1 mRNA and protein levels were significantly up-regulated in CML patients and CML cell lines. Knockdown of SIX1 expression significantly inhibited CML cell proliferation and promoted cell apoptosis. Furthermore, SIX1 as a transcriptional factor positively regulated pyruvate kinase isozyme type M2 (PKM2) expression and played an important role in the Warburg effect. In addition, these findings indicated that miR-140-5p functions as a tumor suppressor and plays a critical role in CML cell apoptosis and metabolism by targeting SIX1. Moreover, the miR-140-5p/SIX1 axis may be a potential therapeutic target in CML.