ABSTRACT
This study is to establish a paclitaxel [PTX]-resistant human cervical carcinoma HeLa cell line [HeLa/PTX] and to investigate its redox characteristics and the expression of taxol resistance gene 1 [Txr1]. HeLa cells were treated with PTX and effects of PTX on cell proliferation were detected through cell counting and the MTT assay. Levels of cellular reactive oxygen species [ROS], reduced glutathione [GSH], and oxidized glutathione [GSSG] as well as the ratio of GSH to GSSG were measured by the 2,7-difluorescein diacetate [DCFH-DA] method and the 5,5?-dithiobis[2- nitrobenzoic acid] [DTNB] method. Activities of superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GPx] were determined by the nitrite formation method, the molybdate colorimetric method, and the DTNB colorimetric method, respectively. The level of Txr1 mRNA was determined by real-time PCR. Compared with the regular HeLa cells, HeLa/PTX cells were larger in size and had more cytoplasmic granules. The population doubling time for HeLa/PTX cells was 1.32 times of that of HeLa cells [P < 0.01]. HeLa/PTX cells showed stronger resistance to PTX than HeLa cells with a resistance index of 122.69. HeLa/PTX cells had higher levels of ROS [P < 0.01] and Txr1 mRNA [P < 0.01], lower level of GSH [P < 0.05], and lower activities of SOD [P < 0.01] and GPx [P < 0.05] than HeLa cells. HeLa/PTX cells, with higher levels of ROS and Txr1 mRNA expression, are more resistant to PTX than HeLa cells