microRNA-223 promotes the growth and invasion of glioblastoma cells by targeting tumor suppressor PAX6.

Glioblastoma is the most common primary central nervous system malignancy and its unique invasiveness hinders effective treatment. Its high invasiveness may be controlled partly by microRNAs (miRNAs, miRs) and their target genes. In the present study, we found that increased miR-223 expression and reduced PAX6 expression coexisted in glioblastoma as detected by quantitative PCR or tissue microarrays. We confirmed that miR-223 directly targets PAX6 through binding to its 3'-UTR using dual luciferase reporter assay. In U251 and U373 glioblastoma cells, overexpression of miR-223 decreased PAX6 mRNA and protein expression; however, inhibition of miR-223 increased PAX6 mRNA and protein expression. Moreover, overexpression of miR-223 led to effects similar to those of PAX6 knockdown: increased cell viability, increased percentage of cells in the G1 phase and increased cell invasiveness parallel with increased MMP2, MMP9 and VEGFA expression. In addition, inhibition of miR-223 resulted in effects similar to those of PAX6 overexpression: decreased cell viability, decreased percentage of cells in the G1 phase and decreased cell invasiveness parallel with reduced MMP2, MMP9 and VEGFA expression. The data presented here suggest that miR-223 promotes the growth and invasion of U251 and U373 glioblastoma cells by targeting PAX6, which serves as a tumor suppressor in glioblastoma exerting the functions of inhibition of cell cycle transition, and the expression of MMP2, MMP9 and VEGFA. In conclusion, the present study supports miR-223 and PAX6 as novel therapeutic targets for glioblastoma.