Abstract
Prostate cancer (PCa), an epithelial malignancy that occurs in the prostate, is the second leading cause of cancer death worldwide. MicroRNAs (miRs/miRNAs) are reported to have important applications in the field of cancer diagnosis and treatment. The present study aimed to investigate the function of miRNA-122 in the chemoresistance of PCa cells and the underlying mechanism. Significantly decreased miR-122 and increased pyruvate kinase (PKM2) levels were observed in docetaxel-resistant PCa cells, and PKM2 was negatively correlated with miR-122. MiR-122 mimic transfection in docetaxel-resistant LNCaP cells significantly inhibited cell proliferation, promoted apoptosis and decreased glucose uptake and lactate production, which was counteracted by PKM2 overexpression. Inhibition of miR-122 in LNCaP cells had an opposite effect to miR-122 mimic transfection. In addition, miR-122 mimic transfection significantly increased the sensitivity of docetaxel-resistant LNCaP cells to docetaxel, while inhibition of miR-122 significantly decreased the sensitivity of LNCaP cells to docetaxel. Luciferase reporter assays showed that miR-122 regulated PKM2 expression by binding to the 3'-untranslated region of PKM2. The results suggest that upregulation of miR-122 could enhance docetaxel sensitivity, inhibit cell proliferation and promote apoptosis in PCa cells,possibly through the downregulation of its target protein PKM2.
Keywords:
apoptosis; glycolysis; microRNA-122; proliferation; prostate cancer; pyruvate kinase.