Influence of c-erbB-2-siRNA to the radiosensitivity of colon cancer cells

OBJECTIVE: To observe the influence of radiotherapy combined c-erbB-2-siRNA plasmid to cell growth, cell cycle, apoptosis and radiosensitivity of colon cancer cells. METHODS: The cells were divided in to three groups (c-erbB-2-siRNA-tranfected, scrambled siRNA construct transfected and no-transfected cells). Using MTT and Flat Cloning method detect the cell growth and radiosensitivity; using flow cytometric detect the cell cycle and the apoptosis rate. RESULTS: A value of 6, 8 Gy X-ray irradiation group and 0, 2, 4 Gy group of spectrophotometry respectively were 0.314±0.035, 0.117±0.009 and 0.721±0.044, 0.608±0.018, 0.584±0.041, and 6 and 8 Gy group were significantly lower than 0, 2, 4 Gy group (P=0.0001); A value of radiation combined c-erbB-2-siRNA in 0, 2, 4, 6, 8 Gy group of spectrophotometry respectively were 0.741±0.024, 0.611±0.071, 0.538±0.041, 0.245±0.029, 0.117±0.011, which were significantly lower than the other two groups (P=0.0001). In 4, 6, 8 Gy X-ray irradiation group and 0, 2 Gy group G ₂/M cell cycle respectively were 12.19±0.41, 15.02±0.38, 18.56±0.94 and 6.50±0.43, 5.26±0.71, the former G ₂/M cell cycle were significantly higher than the latter (P=0.0001); 4 Gy X-ray irradiation combined c-erbB-2-siRNA group, scrambled siRNA construct transfected and no-transfected cells in G ₀/G ₁ cell cycle respectively were 79.93±0.79, 69.34±1.17, 69.40±0.84, The experimental group was significantly higher than the other two groups (P=0.0001). The apoptosis rate of the radiotherapy with 0, 2, 4, 6, 8 Gy had No significantly difference (P=0.065); But the apoptosis rate of 4 Gy X-ray irradiation combined c-erbB-2-siRNA group, scrambled siRNA construct transfected and no-transfected cells were respectively 19.21±3.54, 6.82±0.74, 7.56±0.35, The experimental group was significantly higher than the other two groups (P=0.0001). The radiosensitizer ratio in c-erbB-2 siRNA-tranfected combined radiotherapy group were 1.283 and 1.242, greater than 1. CONCLUSION: C-erbB-2 siRNA-tranfected combined radiotherapy can significantly inhibit the growth of colon cancer cells, obviously induced cells apoptosis, and most especially increase radiosensitivity.