Celastrol with a Knockdown of miR-9-2, miR-17 and miR-19 Causes Cell Cycle Changes and Induces Apoptosis and Autophagy in Glioblastoma Multiforme Cells

Abstract

Glioblastoma multiforme (GBM) is a cancer with extremely high aggressiveness, malignancy and mortality. Because of all of the poor prognosis features of GBM, new methods should be sought that will effectively cure it. We examined the efficacy of a combination of celastrol and a knockdown of the miR-9-2, miR-17 and miR-19 genes in the human glioblastoma U251MG cell line. U251MG cells were transfected with specific siRNA and exposed to celastrol. The effect of the knockdown of the miRs genes in combination with exposure to celastrol on the cell cycle (flow cytometry) and the expression of selected genes related to its regulation (RT-qPCR) and the regulation of apoptosis and autophagy was investigated. We found a significant reduction in cell viability and proliferation, an accumulation of the subG1-phase cells and a decreased population of cells in the S and G2/M phases, as well as the induction of apoptosis and autophagy. The observed changes were not identical in the case of the silencing of each of the tested miRNAs, which indicates a different mechanism of action of miR9-2, miR-17, miR-19 silencing on GBM cells in combination with celastrol. The multidirectional effects of the silencing of the genes encoding miR-9-2, miR-17 and miR-19 in combination with exposure to celastrol is possible. The studied strategy of silencing the miR overexpressed in GBM could be important in developing more effective treatments for glioblastoma. Additional studies are necessary in order to obtain a more detailed interpretation of the obtained results. The siRNA-induced miR-9-2, miR-17 and miR-19 mRNA knockdowns in combination with celastrol could offer a novel therapeutic strategy to more effectively control the growth of human GBM cells.