Differentialradiobiological effects of carboxyfullerene C_3 on K562 and AHH-1 cells

：Objective To investigatethe application prospective of carboxyfullerene C_3 as a radioprotectant or assistant fortumor radiotherapy.Methods Different concentrations of C_3 were incubated with K562 andAHH-1 cell,CCK-8 assay and trypan blue rejection test were performed to examine theinfluence of C_3 on the cell viability.Annexin V/PI staining and flow cytometry assay wereapplied to assess the cell cycle and apoptosis after 7-ray irradiation.Results C_3 showedlittle toxicity to AHH-1 cell with the survival rate over 95% ,but 600 mg/L of C_3markedly inhibited the growth of K562 cell (82%) .Pretreatment of 100 mg/L C_3significantly increased the survival rate of AHH-1 cell after 4 Gy irradiation comparedwith the single radiation group(71.3% vs 90.3%) ,but decreased the apoptosis rate (26.3%vs 12.6%) ,while the survival rate of K562 cell was decreased and the apoptosis rate waselevated with the increase of C_3 concentration.Moreover,the cell cycle analysis revealedthe G_2 phase block in AHH-1 cell after radiation exposure was mitigated by C_3pretreatment,but that in K562 cell was aggravated.Conclusions C_3 has good radioprotectiveeffects on AHH-1 cells.For K562 cell,C_3 could inhibit the cell proliferation,promote theradiation induced apoptosis and aggravate the G_2 phase block.