Correlation between miR-7 and expression of EGFR/PI3K signal pathway related protein in glioma

LIU Liang-hong; ZHANG Hong-yun; LIU Xiao-zhi; ZHANG Li-dong; JIANG Zhong-min

doi:10.3969/j.issn.1002-266X.2014.27.001

Abstract：Objective To explore the correlation between miR-7 and expression of EGFR/PI3K signal pathway relat-ed protein (EGFR, PI3K and AKT2) in brain glioma tissues and U251 cells.Methods The tumor tissues were obtained from 42 patients with brain glioma by excision , including 8 cases of tumor adjacent normal brain tissue .U251 glioma cells were cultured , and then were divided into the blank control group ( only with liposomes ) , nonsense sequence group ( non-sense sequence and liposomes ) and miR-7 transfection group ( transfection of miR-7 gene fragments ) .The expression of miR-7 in the glioma tissues and U251 cells was determined by RT-PCR.The expression of EGFR , PI3K and AKT2 protein in glioma tissues was detected by immunohistochemitry , and RT-PCR and Western blotting were used to detect the mRNA and protein expression of EGFR , PI3K and AKT2 in the U251 cells.Results The mRNA expression of miR-7 in the glio-ma and normal brain tissues were 1.47 ±0.27 and 3.47 ±0.15, respectively (P<0.05).With the increase of pathological grades of glioma, the expression of miR-7 decreased, the EGFR, PI3K and AKT expression increased (all P<0.05).The expression of miR-7 was negatively correlated with EGFR , PI3K and pAKT expression in the glioma tissues (r=-0.754,-0.528 and -0.467, respectively;all P<0.05).The EGFR, PI3K and AKT expression was significantly reduced in the U251 cells after being transfected with miR-7 (all P<0.05).Conclusions The expression of miR-7 in the glioma tissues is down-regulated, which is negatively correlated with the EGFR/PI3K pathway related protein.The expression of EGFR, PI3K and AKT is decreased in the U251 cells after being transfected with miR-7.The EGFR/PI3K pathway may be one of the important mechanisms of miR-7 in regulating the occurrence and development of gliomas .