The effect of miRNA-7 on chemoresistance in esophageal cancer cell TE-1 / 天津医药

ABSTRACT

Objective To explore the impacts of over-expression of microRNA-7 (miRNA-7) on the sensitivity of cis-platin in esophageal carcinoma cell line TE-1, and the possible mechanism thereof. Methods Lipofectmin 2000 method was used to transient transfect with miRNA-7 mimic into esophageal cancer cell line TE-1, which was taken as transfection group, mimic negative control was taken as transfection conrtol group. The expressions of miRNA-7 and epidermal growth factor receptor (EGFR) mRNA were detected by RT-PCR in the above two groups and normal control group. The total EGFR and EGFR in cytoplasmic and nucleus were detected with Western blot assay in transfection group and transfection control group. CCK-8 was used to detect IC50 of cisplatin in transfection group and transfection control group. The expression of EGFR was observed with immunofluorescence confocal microscope in two groups. Results The miRNA-7 expression was signifi-cantly increased in transfection group than that of transfection conrtol group and control group. The expression of EGFR mRNA was significantly reduced in transfection group (P<0.001). The total EGFR was significantly decreased in transfec-tion group than that of transfection conrtol group. The level of nuclear EGFR was significantly increased ( P<0.01),and cyto-plasm EGFR expression was significantly decreased in transfection group than that of transfection control group ( P<0.05). CCK-8 results showed that after the over expression of miRNA-7 in TE-1, the IC50 of cisplatin (48 h) increased in transfec-tion group than that of control group (P<0.01). Immunofluorescence results showed that EGFG in nuclear was higher in transfection group than that of transfection control group but its expressions reduced in cell membrane and cytoplasm. Con-clusion The over-expressed miRNA-7 in esophageal cancer cells TE-1 can reduce cisplatin sensitivity by the increased EGFR in nuclear translocation.