miR-378a-3p regulates glioma cell chemosensitivity to cisplatin through IGF1R

Abstract

Glioma is a type of common intracranial tumor. In this study, we investigated the molecular mechanism by which miR-378a-3p regulates cisplatin (CDDP) chemosensitivity in glioma cells via insulin-like growth factor 1 receptor (IGF1R). U251/CDDP cells were treated with CDDP and transfected with miR-378a-3p mimics, NC mimics, or pcDNA-IGF1R. qRT-PCR was used to measure the differential level of miR-378a-3p. CCK-8 assay was used to test cell proliferation, and flow cytometry was used to analyze apoptosis. The targeting relationship between miR-378a-3p and IGF1R was tested through a dual-luciferase reporter gene assay. In contrast to normal glial cells, the miR-378a-3p level decreased in human glioma U251 cells and had lower expression in U251/CDDP cells. Compared with the CDDP group, miR-378a-3p significantly caused the inhibition of U251/CDDP cell proliferation and enhanced apoptosis in the miR-378a-3p mimics + CDDP group. Another experiment confirmed that IGF1R was a target gene of miR-378a-3p, and overexpression of miR-378a-3p inhibited IGF1R expression. In addition, co-overexpression of miR-378a-3p and IGF1R induced the upregulation of the U251/CDDP cell proliferation and the inhibition of apoptosis in the miR-378a-3p mimics + pcDNA-IGF1R + CDDP group. This study confirmed that miR-378a-3p promoted the sensitivity of glioma cells to CDDP in glioma patients via targeting IGF1R to increase the therapeutic effect during chemotherapy.

Keywords: chemosensitivity; cisplatin; glioma; insulin like growth factor 1 receptor; miR-378a-3p.

Figure 1

Expression of miR-378a-3p in drug-resistant U251/CDDP cells. (a) miR-378a-3p expression was detected by qRT-PCR. (b) Dose–response curve of CDDP administration on glioma cells was detected by the CCK-8 assay. ^** p < 0.01.

Figure 2

Effects of miR-378a-3p on the chemosensitivity of CDDP/U251 cells. (a) qRT-PCR assay was used to validate miR-378a-3p transfection efficiency. (b) Dose–effect curve of CDDP administration on glioma cells after transfection of miR-378a-3p/NC mimics in U251 cells. (c) The proliferation of U251/CDDP cells was detected by the CCK-8 assay. (d) The apoptosis of U251/CDDP cells was detected by flow cytometry. ^* p < 0.05, ^** p < 0.01, and ^*** p < 0.001.

Figure 3

miR-378a-3p directly targets IGF1R. (a) Binding sequences between miR-378a-3p and IGF1R. (b) Dual luciferase reporter assay was used to detect the binding relationship between miR-378a-3p and IGF1R. (c) Western blotting was used to detect the protein expressions. ^** p < 0.01 and ^*** p < 0.001.

Figure 4

miR-378a-3p promotes the sensitivity of CDDP/U251 cells by regulating IGF1R. (a) IGF1R protein expression was detected by Western blotting. (b) Cell proliferation was detected by the CCK-8 assay. (c) Cell apoptosis was detected by Annexin V-FITC/PI and flow cytometry. ^*** p < 0.001.