Abstract: Objective To explore the effect of lncRNA DNM3OS on the proliferation, apoptosis and radio-sensitivity of rectal cancer SW-480 cells and its molecular mechanism. Methods The samples from cancerous tissues and adjacent tissues of 30 rectal cancer patients were selected and the expression of DNM3OS and miR-193a-3p was detected by RT-qPCR; Transfected the inhibited DNM3OS expression vector or over-expression miR-193a-3p vector into SW-480 cells and co-transfect DNM3OS and inhibited miR-193a-3p expression vector into SW-480 cells and then irradiated them with 4 Gy rays; Cell colony formation experiment was applined to detect cell radio-sensitivity; methyl thiazolyl tetrazolium assay (MTT) was used to detect cell proliferation inhibition rate; flow cytometry was used to detect cell apoptosis; The targeted regulation of DNM3OS and miR-193a-3p were examined by dual luciferase reporter gene assay. Results The expression of DNM3OS in rectal cancer tissue was higher than that in adjacent tissues and the expression of miR-193a-3p was lower than that in adjacent tissues (P＜0.05). After inhibiting DNM3OS expression or over-expression of miR-193a-3p, SW-480 cell proliferation inhibition rate and apoptosis rate was increased(P＜0.05); after radiation, cell survival score was decreased and cell proliferation inhibition rate as well as apoptosis rate were increased (P＜0.05). DNM3OS targeted and regulated miR-193a-3p, and interference with miR-193a-3p expression reversed the effect of inhibiting lncRNA DNM3OS expression on the proliferation, apoptosis and radiosensitivity of rectal cancer SW-480 cells. Conclusions Down-regulation of expression of lncRNA DNM3OS can inhibit the proliferation of SW-480 cells by up-regulation of miR-193a-3p, thus to promote cell apoptosis and enhance cell radio-sensitivity.

Key words: lncRNA DNM3OS, miR-193a-3p, rectal cancer, radio sensitivity