Synthetic miR-143 Exhibited an Anti-Cancer Effect via the Downregulation of K-RAS Networks of Renal Cell Cancer Cells In Vitro and In Vivo

To understand the role of RAS-signaling networks in the pathogenesis of renal cell carcisnoma, we clarified the relationship between miR-143 and RAS. The expression of miR-143 was extremely downregulated in tumor tissues from renal cell carcinoma patients compared with that in the adjacent normal tissues and Caki-1 cells. We developed a synthetic miR-143#12, and we found that the ectopic expression of it inhibited cell growth with autophagy in Caki-1 cells. Also, the expression level of c-Myc was markedly decreased, resulting in the perturbation of cancer-specific energy metabolism by negatively modulating the expression of GLUT1 and the PTBP1/PKMs axis. A partial metabolic shift from glycolysis to oxidative phosphorylation induced autophagy through increasing the intracellular level of reactive oxygen species (ROS). In an in vivo study, the potent anti-tumor activity of polyion complex (PIC)-loaded miR-143#12 (miR-143#12/PIC) was shown by systemic administration of it to Caki-1 cell-xenografted mice. Higher levels of miR-143 were found in both blood and tumor tissues after the systemic administration with miR-143#12/PIC compared to those with lipoplexes in the xenografted mice. These findings indicated that this synthetic miR-143#12 induced a marked growth inhibition by impairing K-RAS-signaling networks in vitro and in vivo.