MiR-129-5p enhances the radiosensitivity of thyroid myeloid cell MZ-CRC-1 by inhibiting HMGB1 / 中华放射医学与防护杂志

ABSTRACT

Objective To explore whether MiR-129-5p participates in radiosensitivity of medullary thyroid cell MZ-CRC-1 by inhibiting the gene expression of high mobility group protein B1 ( HMGB1) . Methods The radioresistant cell line MZ-CRC-1/R was established from MZ-CRC-1. Cell survival fraction was analyzed by colony formation assay. The expressions of miR-129-5p in MZ-CRC-1 and MZ-CRC-1/R cells were detected by qRT-PCR. Cell viability was determined by MTT assay. Cell apoptosis was measured by flow cytometry. Dual-luciferase reporter assay was performed to confirm the relationship between miR-129-5p and HMGB1. Besides, the protein expressions of HMGB1 and p-AKt were evaluated by western blot. Results Compared with that of MZ-CRC-1 cells, the survival fraction of MZ-CRC-1/R cells was significantly increased (t=3. 038, 4. 330, 4. 885, 4. 568, P<0. 05), the cell viability of MZ-CRC-1/R cells was also increased ( t=3. 637, 7. 734, 11. 896, 14. 522, P<0. 05) , and the expression of miR-129-5p(0.26±0.03) was significantly decreased in MZ-CRC-1/R cells(1.00±0.06) (t=19. 107, P<0. 05) . Compared with miR-NC-inhibitor group, cell viability was promoted and cell apoptosis was blocked in the miR-129-5p-inhibitor group ( t=5. 156, 6. 005, 9. 649, 8. 659, P<0. 05) . Moreover, miR-129-5p mimic suppressed cell viability and enhanced cell apoptosis after irradiation ( t=3. 118, 5. 034, 6. 005, 7. 488, 6. 362, P<0. 05) . Overexpression of miR-129-5p inhibited the protein expressions of HMGB1 and p-AKt (t=9. 325, 10. 614, P<0. 05). In addition, HMGB1 depletion rescued cell apoptosis that was reduced by miR-129-5p inhibitor in MZ-CRC-1 cells ( t=6. 700, P<0. 05) , while HMGB1 overexpression attenuated the effect of miR-129-5p upregulation on MZ-CRC-1/R cells ( t=7. 073,P<0. 05) . Conclusions miR-129-5p increased the radiosensitivity of medullary thyroid-like cell MZ-CRC-1 by inhibiting HMGB1.