Abstract: OBJECTIVE: To study the effects of a decoction of Fuzhengzengxiao formula on lung adenocarcinoma regarding the inflammatory protein S100A9 known to enhance cancer cell sensitivity.METHODS: A nude mouse model of human lung adenocarcinoma was established. The mice were randomly divided into four groups using the random number table method: Group Ⅰ, control;Group Ⅱ, treatment with a decoction of the Fuzhengzengxiao formula alone; Group Ⅲ, treatment with radiotherapy alone; and Group Ⅳ, treatment with radiotherapy plus a decoction of Fuzhengzengxiao formula. When the tumor body was 1 cm~3 in diameter, the tumor bearing mice in GroupsⅢ and Ⅳ were irradiated at a single dose of 10 Gy and the tumor inhibition rate was evaluated.The expression of S100A9 was determined using Western blotting and q-PCR(Real-time Quantitative PCR Detecting System). The sensitivity of cells containing RNAi S100A9 to radiotherapy was evaluated using the Click multiple target model,and the cell cycle was analyzed using flow cytometry.RESULTS: Relative to the control group,the expression of S100A9 in the tumors in each treatment group was decreased,especially in Group Ⅳ. The sensitizing enhancement ratio(SER) Dq was >1 after RNAi S100A9; it decreased the surviving fraction after a 2 Gy dose exposure,and also the D_0 and Dq of the tumor cells; in addition, the radiosensitivity of G_2/M cells was significantly increased.CONCLUSION: The decoction of the Fuzhengzengxiao formula downregulated the expression of S100A9 in lung adenocarcinoma cells.

Key words: Calgranulin B, RNA interference, Radiation tolerance, Adenocarcinoma of lung, Fuzhengzengxiao formula