Abstract: Objective: To observe the inhibitory effect of Endostar combined with radiotherapy on transplanted CNE1 Nasopharyngeal Carcinoma(NPC) in BALB/c nude mice and explore the relationship of this inhibitory effect with the expression level of VEGF and apoptosis inhibiting protein-Survivin..Methods: The transplanted tumor model of human CNE1 nasopharyngeal carcinoma on nude mice was established to evaluate the antitumor activity of Endostar combined with radiation (Endostar+radiation,D group) treatment compared with monotherapy (Endostar,B group or radiation,C group).The growth characteristics of transplanted tumor were recorded. Transmission electron microscopy were used to observe the morphological changes of cell apoptosis. Real-time quantitative PCR was used to determine the effect on VEGF and Survivin mRNA expression level of of tumor tissues.Results: Significant on the tumor growth was found ,and more typical morphological changes were seen in cancer cells in D group. Level of VEGF in tumor tissue of D group was lower than that of C group ,B group or A group(P<0.05). And the level of Survivin in D group were much lower than in other three groups(P<0.05). The results of linear Correlation relevant analysis showed that there exist positive correlation between the inhibitory effect and the expression of VEGF and Survivin (r = 0.679, P < 0.01).Conclusion: Endostar could enhance the radiosensitivity of NPC transplantation tumor in nude mice to radiation.The mechanism may be down-regulating the expression of VEGF and Survivin.

Key words: Endostar, Nasopharyngeal Carcinoma, radiosensitivity, VEGF