Down-regulation of miR-21 expression enhances the radiosensitivity of TE-1 cells in vitro / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To study the effect of miR-21 down-regulation on the radiosensitivity of TE-1 cells in vitro.</p><p><b>METHODS</b>TE-1 cells were transfected via lentivirus with a vector containing the antisense oligonucleotides of miR21, and the subclones with stable down-regulation of miR21 expression were selected with puromycin and designated as TE-1-miR21(-), whose expression level of miR21 was determined using real-time quantitative PCR. The radiosensitivity of TE-1 and TE-1-miR21(-) cells were evaluated with colony formation assay, and the expressions of β-catenin was determined using Western blotting and RT-PCR. Flow cytometry was used to analyze the proportion of p75NTR(+) cells in TE-1 and TE-1-miR21(-) cells.</p><p><b>RESULTS</b>A cell subclone stably expressing a low level of miR21 was obtained and verified by real-time quantitative PCR. Colony formation assay showed an enhanced the radiosensitivity of TE-1-miR21(-) cells compared to parental TE-1 cells. RT-PCR revealed no significant changes in β-catenin mRNA expression in TE-1-miR21(-) cells, whereas its β-catenin protein expression was markedly suppressed by high-dose (8 and 10 Gy) irradiation. Flow cytometry assay showed a decreased proportion of p75NTR(+) cells in TE-1-miR21(-) cells compared to that in TE-1 cells.</p><p><b>CONCLUSION</b>Down-regulation of miR21 can enhance the radiosensitivity of TE-1 cells, which might result from the inactivation of wnt/β-catenin signal pathway and a decreased p75NTR(+) cell proportion.</p>