The Expression And Significance Of P-glycoprotein, Lung Resistance Associated Protein, And Topoismerase Ⅱ In Cells Of Hypopharyngeal Carcinoma Induced By 5-fluorouracil

Objective: To establish a multidrug-resistant cell line Hep-2/5-Fu of hypopharyngeal carcinoma.Methods: Hep-2/5-Fu was induced by continuous stepwise exposure to 5-fluorouracil in vitro . MTT assay was used to determine the 50% inhibiting concentration of Hep-2 and Hep-2/5-Fu.then calculate its resistance index(RI). Biological characteristics of the Hep-2 and Hep-2/5-Fu cell line were observed including morphological changes, cell growth curve, doubling time. The protein expression and mRNA of P-glycoprotein, lung resistance associated protein, and topoismeraseâ…¡was evaluated by immuno- cytochemical method and RT-PCR.Results:The acquired MDR cell line of Hep-2/5-Fu was established successfully after seletcted by 5-fluorouracil for two months. The Hep-2/ 5-FU cells tended to grow in clusters in vitro . It was found that the doubling time of Hep-2/5-Fu cells was longer than that of its parental cells . The IC50 of 5-fluorouracil was from 2ug/ml in Hep-2 up to 60ug/ml in Hep-2/5-Fu. The protein expression of P-glycoprotein, lung resistance associated protein in Hep-2/5-Fu was significantly higher than that of the parental cells,whereas the protein expression of topoismeraseâ…¡.Conclusion: Establishment of the cell line Hep-2/5-Fu might be beneficial to the studies of hypopharyngeal carcinoma 5-Fluorouracil acquired MDR mechanisms and the selection of reversal modif iers .