Study on Biological Characteristics and Mechanism of Paclitaxel Induced Drug Resistance in Endometrial Carcinoma Cells.

Objective. To study the biological characteristics of paclitaxel resistant endometrial carcinoma cells and its mechanism of drug resistance. Method. The paclitaxel resistant cell lines were established by high-dose paclitaxel (TAX) injection. The IC50 of paclitaxel was determined by CCK-8 assay in Ishikawa and Ishikawa-TAX. The cell cycle and apoptosis rate were detected by flow cytometry. Western blot was used to detect the expression of p-AKT and p-p70S6K. The expression of drug resistance-related genes P-gp and MDR1 was determined by RT-PCR. Cell viability was determined by soft agarose assay and invasive ability in vitro by transwell assay. Results. Paclitaxel and NVP-BEZ235 cotreatment group can further inhibit the clonogenicity and invasion of Ishikawa and Ishikawa-TAX cells compared with paclitaxel alone and NVP-BEZ235 treatment group. Paclitaxel and NVP-BEZ235 cotreated groups increased the apoptosis rate of Ishikawa and increased G0/G1 phase arrest in both cells. Paclitaxel alone significantly inhibited p-AK and p-p70 S6K protein expression in Ishikawa and Ishikawa-TAX cells and the inhibition was enhanced by NVP-BEZ235 when cotreated with paclitaxel. Conclusion. Paclitaxel can inhibit Ishikawa and lshikawa-TAX cell via PI3K/Akt/mTOR signaling pathway. Paclitaxel and NVP-BEZ235 cotreatment can enhance the inhibitory effect.