Impact of RNAi targeting survivin gene on tumor growth, apoptosis and radiosensitivity in nude mice xenograft of human cervical carcinoma

Background and purpose:Recently, survivin gene is one of the hot spots in tumor study. The purpose of the present study was to observe the impact of RNAi targeting survivin gene on tumor growth, apoptosis and radiosensitivity in nude mice xenograft of human cervical carcinoma. Methods:HeLa-s2, HeLa-NC, HeLa-U6 neo and HeLa cells were inoculated respectively in flank subcutaneous tissue of 24 female nude mice so as to establish xenograft models of human cervical carcinoma randomly. The tumor growth status was observed. The tumor volume was regularly measured and the tumor weight was investigated used to observe the impact of RNAi targeting survivin gene on tumor growth. The expression of survivin protein and FⅧRAg in tumor tissues were examined by immunohistochemistry SP method MVD was calculated. Cell apoptosis in tumor tissues was observed by HE staining, apoptotic index(AI) was quantif ied by TUNEL method. To observe the impact of RNAi targeting survivin gene on tumor radiosensitivity after irradiated, the tumor growth delay and tumor weight were investigated and cell apoptosis were examined by TUNEL method. Results:We established 4 groups of xenograft models of human cervical carcinoma. The tumor volume of HeLa-s2 group was obviously less than that of HeLa group at every checkpoint. The tumor weight of HeLa-s2 group was obviously lower than that of HeLa group, and they were(0.369±0.043)g and (1.150±0.136)g respectively(P0.05).The tumor growth inhibitive rate of HeLa-s2 group was 67.9%. The expression of survivin protein FⅧRAg examined by immunohistochemistry in tumor tissues of HeLa-s2 group decreased sharply and MVD went down to 23.4±3.1. Apoptotic cells increased in tumor tissues of HeLa-s2 group examined by HE staining and TUNEL method, AI was (22.7±1.4)%. The tumor volume of HeLa-s2 group was obviously less than that of HeLa group at every checkpoint after irradiation and the tumor weight of HeLa-s2 group was obviously lower than that of HeLa group, they were:(0.41±0.06)g and(1.38±0.29)g respectively(P0.05). Cell apoptosis increased in tumor tissues of HeLa-s2 group. Compared with HeLa group, AI of HeLa-s2 group rose up notably,they were(30.06±0.98)% and (4.17±0.64)%(P0.05). Conclusion:RNAi for survivin gene can reduce MVD in xenograft by inhibiting survivin protein expression, thus inhibit tumor growth and induce cell apoptosis. Survivin gene RNAi can also enhance tumor radiosensitivity.