Effect of ionizing radiation combined with inhibitors or inducer of autophagy and apoptosis on MCF7 cell / 中华放射医学与防护杂志

ABSTRACT

Objective To detect the inhibiting effects of ionizing radiation combined with inhibitors or inducer of autophagy and apoptosis on MCF7 cell line,and to provide the evidence for human breast cancer therapy radiation.Methods MCF7 cells were exposed to X-rays and randomly divided into 4 groups,including 0 Gy,4 Gy,4 Gy+rapamycin,4 Gy+3-MA,and 4 Gy+z-VAD-fmk groups,including 0 Gy,4 Gy,4 Gy+rapamycin,4 Gy+3-MA,and 4 Gy+z-VAD-fmk groups,respectively.The growth doubling time was calculated by MTT method.The specific protein expressions of LC3 autophagy and beclinl were detected by using Western blot and the difference of Drotein contents wasLC3 autophagy and beclinl were detected by using Western blot and the difference of Drotein contents was compared.The percentage of apoptosis of MCF7 cells was measured by flow cytometry (FCM).Resuits The growth doubling time of MCF7 cells in 4 Gy group wag longer than that in O Gy group(t=4.41,P<O.05),but shorter than that in 4 Gy+rapamycin group(t=4.35,P<0.05).Compared to 4 Gy+rapamycin group,both of the growth doubling time in 4 Gy+3-MA and 4 Gy+z-VAD-fmk groups were shorter(t=4.32,P<O.05).The expressions of beclinl and LC3-Ⅱ proteins in 4 Gy+rapamycin group were the highest,while those in 4 Gy+3-MA group the lowest.Except for 4 Gy+3-MA and 4 Gv+z-VAD-fmk groups,there were significant differences among the other groups in two protein expressions(t=3.9 1-4.78,P<0.05).Conclusions Ionizing radiation could induce MCF7 cell autophagy,ptomote the apoptosis of tumor ceils in combination with autophagy inducer.Ionizing radiation combined with autophagy inhibitor might inhibit the development of autophagy,and delay the apoptosis of tumor cells.