Inhibitory Effect of miR-504-Loaded Magnetic Iron Oxide Nanoparticles on Oral Cancer Through Regulation of Cyclin-Dependent Kinase 6 to Mediate Extracellular Regulated Kinase Signaling Pathway

Abstract

By combining magnetic iron oxide nanoparticles (MIONs) with miR-504, we explored miR-504’s impact on oral cancer cell migration and explored its underlying mechanism with CDK6 protein in oral cancer. Quantitative reverse transcription PCR (RT-qPCR) was used to determine miR-504 expression in oral cancer cells and normal oral cells. Functional experiment was established to analyze the effect of miR-504 and CDK6 on cancer cells migration using Transwell assay, we also determined the interaction between miR-504 and CDK6, which was further verified by bioinformatics and dual-luciferase assay. Western blot determined related proteins of ERK signaling pathway after transfection with different plasmids. miR-504 was poorly expressed in oral cancer cells relative to normal human oral cells (P < 0.05). As RT-qPCR confirmed the transfection efficiency of miR-504 mimic, we found that, overexpression of miR-504 induced decreased protein expression of CDK6 while its mRNA expression did not change. Mechanistically, miR-504 was indicated to bind to CDK6 mRNA3′UTR. Transfection with miR-504 mimic decreased invasion of oral cancer cells, which was reversed by overexpression of CDK6. SCC-9 cells transfected with different plasmids were stimulated with epidermal growth factor. Besides, overexpression of miR-504 downregualted ERK, MMP-2 and MMP-9 protein in oral cancer cells, and addition of CDK6 mimic could restore these expressions (P < 0.05). CDK6 is the downstream target for miR-504. Moreover, the miR-504-loaded MIONs directly targeted CDK6 to mediate the ERK signaling pathway, thereby inhibiting oral cancer migration. It may become a target for treatment of oral cancer.