Study of sensitization effect of hydroxyurea on chemoradiotherapy of human glioma U251 cells / 中华放射肿瘤学杂志

ABSTRACT

Objective:To investigate the effect of hydroxyurea (HU) combined with temozolomide (TMZ) and radiotherapy (RT) on the sensitivity of human glioma U251 cells to chemoradiotherapy (CRT).Methods:Human glioma U251 cell line was cultured in vitro. CCK8 cell assay was used to detect the proliferation activity of U251 cells treated with different concentrations of HU/TMZ under different conditions. Flow cytometry was utilized to detect apoptosis rate and cell cycle distribution of U251 cells. Transwell chamber assay and scratch test were performed to evaluate the changes of cell invasion and migration. The expression levels of apoptosis proteins were determined by Western blot. Colony formation assay was adopted to detect the cell survival fraction . Results:HU concentration at 50μmol/L and below did not affect the proliferation of human glioma U251 cells ( P>0.05). Low-dose HU combined with CRT significantly inhibited cell proliferation ( P<0.05), invasion ( P<0.01) and migration (12h P<0.001, 24h P<0.01), and promoted cell apoptosis ( P<0.01) compared with the use of CRT alone. Application of 50μmol/L HU combined with RT increased the radiosensitivity of cells (SER=1.49), significantly prolonged the cell cycle of S phase and G 2 phase (both P<0.05), considerably up-regulated the expression levels of the apoptosis-associated proteins of Caspase-3 and Bax and significantly down-regulated the expression level of anti-apoptosis protein of Bcl-2(all P<0.001). Conclusions:Compared with CRT, HU combined with CRT can further inhibit the proliferation, invasion and migration of human glioma U251 cells, promote cell apoptosis, increase the radiosensitivity and prolong the cell cycle of S and G 2 phases, thereby enhancing the sensitivity of human glioma U251 cells to CRT.