The Experimental Study Of Herceptin Combined With 5-Fu And Paclitaxel On Gastric Cancer In Vitro

Objectives:1. To study the influence of the different combination schedule with paclitaxel and 5-FU on the proliferation of Her2-positive and Her2-negative gastric cancer cell lines in vitro,and to determine the optimal combination schedule by comparing the difference of sensitivity to chemotherapy on these two gastric cancer cell lines.2. To study the influence of Her-2/neu monoclonal antibody on the proliferation of Her2-positive and Her2-negative gastric cancer cell lines in vitro, and to evaluate the potential application value of the immunotherapy of gastric cancer.3. To evaluate the synergistic effect of Herceptin combined with paclitaxel and 5-FU to Her2-positive and Her2-negative gastric cancer cells lines so as to ascertain the optimal therapy schedule and to provide preclinical evidence for the molecular targeted therapy of gastric cancer.4. To investigate the preliminary mechanism of Herceptin on gastric cancer cell lines.Methods:1. Detecting the growth inhibitory effects of paclitaxel,5-FU or Herceptin alone in various concertrations or in combination on MGC803,N87 cell lines by MTT assay, determining the combination effect of two drugs based on median-effect principle.2. Flow cytometry was used to determine the effect of paclitaxel,5-FU and Herceptin alone or in combination on cell cycle and on the apoptosis of MGC803,N87 cells as well as the influence of Herceptin to Her-2 protein expression on N87 cells. 3. Western-blot method was used to detect the influence of Herceptin alone or combined with paclitaxel,5-FU to the expression of AKT,P-AKT on N87 cells.Result:1. On MGC803 and N87 cells , the best sequence of paclitaxel combined with 5-FU is paclitaxcel given for 24h followed by 5-FU given for 48h. The combination of paclitaxcel and 5-FU on MGC803 cells is more effective than that on N87 cells.2. NO growth inhibition was observed both MGC803 and N87 cells, when Herceptin was used alone.3. Herceptin augments the cytotoxicity of paclitaxcel and 5-FU when given after chemotherapeutic agents in N87 cells , but not in MGC803 cells.4. After 2-days Herceptin exposure, S-phase fraction and expression of Her-2 protein decreased in N87cell. Herceptin combined with paclitaxel,5-FU can inhibit the expression of P-AKT in N87, but no effect on AKT.Conclusion:The should be the optimal schedule and the fittest patients for the treament of gastric cancer when paclitaxel combined with 5-FU. Herceptin had no growth inhibitory effects on Her-2/neu overexpression gastric cancer cells in vitro, but can increase cytotoxicity by following paclitaxel and 5-FU administration.