Effect of lncRNA CRNDE targeting miR-384 on radiosensitivity of colorectal cancer cells

Objective To study the effect of LncRNA CRNDE on radiosensitivity of colorectal cells and underlying mechanism. Methods Colorectal cancer HT-29 cells were transfected with CRNDE shRNA and the interference efficiency was determined by Real time PCR. HT-29 cells transfected with CRNDE shRNA or co-transfected with CRNDE shRNA and miR-384 inhibitor were irradiated at 8 Gy dose, then cell proliferation and apoptosis were detected by MTT and flow cytometry assay, respectively, and cell radiosensitivity was evaluated by cloning assay. It was predicted by a bioinformatics software that CRNDE and miR-384 have complementary binding sites, and this was identified by a luciferase reporting system. Results CRNDE shRNA reduced the expression of CRNDE in HT-29 cells(1.00±0.08 vs. 0.42±0.06, t=10.051, P<0.05). Both CRNDE shRNA and radiation inhibited the proliferation and induced apoptosis of HT-29 cells, and their combination treatment had synergistic effect in apoptosis induction [Apoptosis rates: (2.27±0.13)%, (23.58±2.35)%, (26.91±2.81)%, (36.84±3.24)%, F=24.660, P<0.05; A values: 0.45±0.06, 0.30±0.02, 0.28±0.03, 0.20±0.02, F=106.207, P<0.05]. Transfection of CRNDE shRNA increased the radiosensitivity of HT-29 cells with a radiosensitization ratio of 1.374. CRNDE negatively regulated the expression of its target miR-384. The miR-384 inhibitor antagonized the effect of CRNDE shRNA on proliferation inhibition and apoptosis promotion of radiation-treated colorectal cancer cells. Conclusions Down-regulation of LncRNA expression enhances the radiosensitivity of colorectal cancer cells by regulating miR-384 expression. Key words: Colorectal cancer; Colorectal neoplasia differentially expressed(CRNDE); miR-384; Radiosensitivity