@@

Objective:To evaluate the effect of long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) on the radiosensitivity in breast cancer cells by regulating the miR-149-5p/ glutamic pyruvic transaminase 2 (GPT2) axis.Methods:Real-time reverse transcription PCR (RT-qPCR) was used to detect NEAT1, miR-149-5p and glutamic pyruvic transaminase 2 (GPT2) mRNA levels in human breast cells MCF-10A, and human breast cancer cells MCF-7, MDA-MB-231 and MDA-MB-468, respectively. MCF-7 cells were divided into 0, 2, 4, 6 and 8 Gy irradiation groups. MCF-7 cells were divided into NEAT1 knockdown (si-NEAT1) group and control (si-NC) group, NEAT1 knockdown +miR-149-5p knockdown (si-NEAT1+anti-miR-149-5p) group and control (si-NEAT1+anti-miR-NC) group, NEAT1 knockdown + GPT2 overexpression (si-NEAT1+GPT2) group and control (si-NEAT1+NC) group. On the basis of the above grouping, irradiate each group of cells with 4 Gy radiation for 2 h, denoted as IR+si-NEAT1, IR+si-NC, IR+si-NEAT1+anti-miR-149-5p, IR+si-NEAT1+anti-miR-NC, IR+si-NEAT1+GPT2, IR+si-NEAT1+NC groups. Subsequently, MCF-7 cells were irradiated at a dose of 4 Gy and divided into the IR+si-NEAT1, IR+si-NC, IR+si-NEAT1+anti-miR-149-5p, IR+si-NEAT1+anti-miR-NC, IR+si-NEAT1+GPT2 and IR+si-NEAT1+NC groups. RT-qPCR was used to detect NEAT1, miR-149-5p, GPT2 mRNA levels in cells. Colony formation assay was used to detect cell radiosensitivity. CCK-8 assay was adopted to detect cell proliferation ability. The binding sites of NEAT1 and miR-149-5p were predicted by StarBase database. The binding sites of miR-149-5p and GPT2 were predicted by Targetscan database, and validated by dual luciferase assay. Single factor ANOVA was used for inter-group comparisons. LSD- t test was used for pairwise comparison. Results:Compared with MCF-10A cells, NEAT1 and GPT2 mRNA levels in cell lines were up-regulated, whereas miR-149-5p level was down-regulated (all P<0.05). Compared with the 0 Gy dose group, NEAT1 and GPT2 mRNA levels were down-regulated, while miR-149-5p levels were up-regulated in the 2, 4, 6, and 8 Gy dose groups (all P<0.05). Knockdown of NEAT1 expression or radiation alone could enhance cell radiosensitivity, and reduce cell proliferation ability (all P<0.05). Simultaneous radiation treatment with knockdown of NEAT1 expression could strengthen the above effects upon cells (all P<0.05). Knockdown of miR-149-5p expression or overexpression of GPT2 could partially reverse the aforementioned effects of knockdown of NEAT1 expression (all P<0.05). Conclusion:Knockdown of NEAT1 expression enhances breast cancer cell radiosensitivity, and reduces cell proliferation ability by regulating the miR-149-5p/GPT2 signal axis.