The Inducement And Mechanism Of Immune Co-stimulatory Molecule B7-h1 By Chemo-preventive Agents In Colon Cancer Cell Line Sw480

Purpose: To study the inducement and related mechanism of B7-H1 molecular in SW480 cells when treated by chemo-preventive agents: 5-fluorouracil and paclitaxel.Method: Measure B7-H1 mRNA by RT-PCR 24 hours after 5-fluorouracil and paclitaxel treatment of SW480 cells. Measure B7-H1 protein by immunofluorescence and flow cytometry 48 hours after 5-fluorouracil and paclitaxel treatment of SW480 cells.Results: We demonstrate that chemopreventive agents 5-fluorouracil, paclitaxel can induce protein expression of B7-H1 molecular in SW480 cells. In immunofluorescence study, a stronger fluorescence signal can be observed when SW480 cells was stimulated by paclitaxel ( 2.5μM ) and 5-fluorouracil ( 10μg/ml ) for 48 hours. In flow cytometry study, we can semi-quantitatively detected an increased signal of B7-H1 protein after treatment. However, when measured by semi-quantitative RT-PCR, the mRNA of B7-H1 was not increased 24 hours after treatment. The agent interferon-γwhich was used in this study as a positive control to induce B7-H1 protein, did not cause an increase of B7-H1 mRNA either.Conclusion: Our results suggested chemotherapy's limited clinical effects might be related to the increased protein expression of B7-H1 caused by chemotherapeutic agents. At the same time, our results also suggested the posttranscriptional regulation of B7-H1 molecular.