[Inhibition of tongue cancer development in nude mice transfected with adenovirus carrying human endostatin gene].

Background & Objective: The squamous cell carcinoma of tongue is one of the most common malignant tumors of oral cavity. Surgical therapy is now the mainstay of combined treatment for tongue squamous cell Carcinoma with chemotherapy and radiotherapy. The overall 5-year survival rate was about 50%. The antiangiogenesis therapy has become a new approach of the treatment of tongue carcinoma. This paper was designed to study the characteristics of endostatin expression in tongue cancer cell line (Tca8113), human embryonic epithelial cell line (ECV) and the inhibition of carcinogenesis in nude mice, xenografted with Tca8113, after transfected with recombined adenovirus (Ad/hEnd) which was cloned with human endostatin gene in EI mutated region.

Methods: (1) To determine the expression and distribution of endostatin in Tca and ECV cells transfected with Ad/hEnd using immunohistochemistry. To determine the endostatin in supernatants of Tca cells transfected with Ad/hEnd using ELISA method. To examine the characteristics of endostatin gene expression in Tca8113 and ECV cells by Western blot analysis. (2) To determine the inhibition rate of proliferation and apoptosis rate of ECV cells by WST-1 test and flow cytometry (FCM), respectively.(3) To observe the inhibition of tumor growth in xenografted nude mice with Tca8113 cells by Ad/hEnd administration.

Results: (1) Immunohistochemistry detection indicated that the endostatin was expressed in cytoplasm of Tca8113 cells and ECV cells transfected with Ad/hEnd. Endostatin expression in the supernatant was dose-dependent with the highest to 597 ng/ml. The expression of endostatin in Tca cells was detectable from 1 day to 7 day. Ad/hEnd inhibited ECV cell growth in dose-dependent manner. (2) FCM showed that Ad/hEnd arrested ECV cells in S and G(2) phase and induced apoptosis.(3) The tumor growth curve showed that Ad/hEnd significantly repressed xenograft tumor growth with Tca cell in nude mice; the inhibition rate on Ad/hEnd administrated groups was 45.8% in the 3rd week.

Conclusion: Ad/hEnd expressed efficiently in Tca8113 and ECV cells. Ad/hEnd can change the cell cycle distribution of ECV cells and induce apoptosis and inhibit proliferation of ECV cells. Ad/hEnd could inhibit the growth of tongue carcinoma in xenograft nude mice.