MicroRNA-145 Promotes the Phenotype of Human Glioblastoma Cells Selected for Invasion.

Novel treatment strategies aiming to eliminate or attenuate the invasive phenotype of glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor, could offer a profound therapeutic benefit to patients. We previously demonstrated one method to create invasive sub-populations of GBM cells (IM3 cells) and a positive regulatory role for the miR-143/-145 locus in enhancing the invasion of GBM cells. Herein, we investigated the correlation between miR-145 and srGAP1 (SLIT-ROBO Rho GTPase-activating protein1) that is purported to be a target of miR-145 and involved in migration and invasion. IM3 cells were created by a serial selection by using Boyden chambers®. Antisense-miR-145 was transfected into IM3 cells by using lipofectamine 2000. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blot were employed to analyze the expression of srGAP1. The invasiveness of U87-IM3 and U251-IM3 is attenuated by transfection of antisense miR-145. In addition, srGAP1 was down-regulated in U87-IM3 and U251-IM3 cells compared to parental cells. The elevated miR-145 present in invasive glioblastoma cells (IM3 cells) targets and down-regulated srGAP1, thereby allowing downstream G-proteins to remain in their active state and promote the observed invasive phenotype.