The effects of radiotherapy combined with erlotinib on nasopharyngeal carcinoma xenografts in nude mice

YUAN Tai-ze; ZHANG Huan-huan; LI Jian; LIANG Ying; ZHANG Xiu-ping

Abstract：Objective To investigate the effects of radiotherapy combined with erlotinib on nasopharyngeal carci -noma (NPC) xenografts in nude mice.Methods The NPC cell lines CNE2 were injected s.c.into the hind legs of athy-mic nude mice.When tumor volume was approximately between 100 -200 mm 3 , nude mice were randomly divided into four groups: control, erlotinib, radiation and radiotherapy in combination with erlotinib groups .Radiotherapy was delive-red with 8 Gy in one time on the first day of randomization .Erlotinib was administered by oral gavage (1.6 mg once dai-ly) for 2 weeks.The nude mice were sacrificed 1 week after stopping the treatment , and the tumor size and weight were measured.The expression of epidermal growth factor receptor (EGFR) and phosphorylated EGFR (p -EGFR) were de-tected in histologic sections of xenografts by immunohistochemistry and analyzed by statistical method .Results Erlotinib combined with radiotherapy could significantly slow down tumor growth .Tumor weights in control group , erlotinib group, radiotherapy group and radiotherapy in combination with erlotinib group were (2.60 ±1.51), (1.56 ±0.67), (0.71 ± 0.42) and (0.48 ±0.31) g, respectively.Compared with erlotinib group or radiotherapy group , radiotherapy in combina-tion with erlotinib group significantly inhibited the growth of xenografts in nude mice (P =0.026, P =0.047).There was no significant difference in expression of EGFR among the 6 groups.Conclusion Erlotinib can enhance radiosensitivity of NPC by the inhibition of EGFR phosphorylation .