Abstract: Objective  To explore the expression of ErbB3 in osteosarcoma cell lines Saos-2 and its significance. Methods  Real-time quantitative PCR was used to detected ErbB3 mRNA expression in osteosarcoma cell lines Saos-2 and normal human osteoblasts cell lines N704, and Western blotting was used to detected ErbB3 protein expression. Short hairpin RNA was used to construct ErbB3 knockdown cells and the cell count in 0-3 d was detected. The 48 h survival rates of ErbB3 knockdown cells and normal Saos-2 cells were detected in the presence of 0-100 μmol/L paclitaxel. Results  Real-time quantitative PCR showed significant enhanced ErbB3 mRNA expression in Saos-2 cells compared with N704 ［(4.15±0.04) times, t=7.31, P＜0.05］, and Western blotting showed significant enhanced ErbB3 expression in Saos-2 cells compared with N704. As compared with normal Saos-2 cells, ErbB3 knockdown could reduce the Saos-2 cells proliferation, at the first three days in culture, the Saos-2 cell number of ErbB3 silent was (22.2±2.9) thousand, and the control was (45.8±4.1) thousand, with statistical significance (t=8.23, P＜0.05). Moreover, ErbB3 knockdown could reduce the Saos2 cells tolerance to paclitaxel, when treated with 20 μmol/L paclitaxel, surviving cells in ErbB3 silent group was (43.2±4.7)%, and the control was (61.4±5.9)%, with statistical significance (t=6.74，P＜0.05). Conclusion  ErbB3 highly expresses in Saos-2 cells, ErbB3 expression can enhance the proliferation of Saos-2 cells and the tolerance of Saos-2 cells to paclitaxel.

Key words: Osteosarcoma, RNA interference, Paclitaxel