A preliminary study on radiosensitization effect of nano Fe3 O4/C225 complex on human colorectal cancer LoVo cells

MENG Qinghong; SUN Xinchen; SUN Suping; YU Jingping; NI Xinchu; ZHAO Di

Abstract：Objective To investigate the radiosensitivity enhancement and possible mechanism of nano Fe3 O4/C225 complex on human colorectal cancer LoVo cells. Methods In vitro inhibition rates of cell proliferation at 24h after treatment with different con-centrations (0, 3?125, 6?25, 12?5, 25, 50, 100 mg/mL) of nano Fe3O4/C225 complex were determined by MTT. According to the experimental protocol, the below experiments were carried out in irradiation group, C225+irradiation group and complex+irradiation group. The colony formation assay was employed to observe the surviving fraction ( SF) of three groups after X-ray irradiation of 0, 2, 4, 6, 8, 10Gy. The cell cycle of three groups at 24h after X-ray irradiation of 4Gy was measured by flow cytometry. Western blotting was employed to measure the protein level of epidermal growth factor receptor ( EGFR) and p-P38, p-Akt in the related of signaling pathway. Results The proliferation inhibition rate of LoVo cells gradually increased with the increasing concentration of Fe3 O4/C225 complex ranging from 3?125 to 100 mg/L. The proliferation inhibition rates were 0%, (8?950± 0?086)%, (14?760± 0?011)%, (29?860± 0?001)%, (41?750± 0?017)%, (59?770± 0?010)% and (78?710± 0?017)% at the concentrations of 0, 3?125, 6?25, 12?5, 25, 50, 100mg/mL with statistically significant differences ( P<0?05) . Compared with irradiation group and C225+irradiation group, there were lower SF, percentage of S cells and protein levels of p-Akt, EGFR and higher percentages of G0/G1 and G2/M and protein level of p-P38 in complex+irradiation group with statistically significant differences (P<0?05). Conclusion Nano Fe3O4/C225 complex could inhibit the proliferation of LoVo cells with radiosensitizing effect possibly via the arrest at the G0/G1 phase and in-hibition of EGFR signaling pathways.