Abstract:

Objective  To investigate the effect of silenced chitinase 40 （YKL-40） expression on cisplatin-resistant endometrial cancer cell line Ishikawa／DDP. Methods Ishikawa／DDP drug-resistant cell lines were established by DDP long-term concentration gradient method in vitro， and the expression of MDR1， Bcl-2， Bax and caspase-3 were detected. The proliferation activity of Ishikawa cells and Ishikawa／DDP cells was detected by MTT method， and the half inhibitory concentration （IC50） was calculated. Ishikawa／DDP was transfected with NC negative sequence （NC group） and siRNA YKL-40 （si-YKL-40 group）， respectively. The untransfected cells were set as blank control group. The effects of DDP on proliferation， migration and apoptosis of Ishikawa／DDP cells in si-YKL-40 group were detected by MTT， scratch test and Annexin V／PE double staining. Results Ishikawa／DDP resistant cell lines were successfully established in vitro. The inhibitory rates of 3.125， 6.25， 12.5， 25， 50 and 100 μmol／L DDP on proliferation of Ishikawa／DDP cells were （6.93±2.45）％， （8.14±4.50）％， （11.37±4.62）％， （15.18±3.97）％， （26.29±5.08）％， （41.32±7.64）％， which were significantly lower than those of Ishikawa cells （P＜0.05）. The IC50 were 14.58 μmol／L and 116.70 μmol／L， respectively. The resistance index of Ishikawa／DDP was 8.004. The expression of YKL-40， MDR1 and Bcl-2 in Ishikawa／DDP cells were 1.87±0.40， 2.34±0.46 and 1.52±0.28， which were higher than those in Ishikawa cells （P＜0.05）. The expression of Bax and caspase-3 in Ishikawa／DDP cells were 0.72±0.21 and 0.49±0.17， which were lower than those in Ishikawa cells （P＜0.05）. The inhibitory rates of 3.125， 6.25， 12.5， 25， 50 and 100 μmol／L DDP on the proliferation of si-YKL-40 cells were （10.95±2.74）％， （18.73±5.30）％， （32.79±5.47）％， （52.28±6.58）％， （61.73±5.26）％， （65.45±7.33）％， respectively， which were significantly higher than those of blank control group and NC group （P＜0.05）. The IC50of DDP on si-YKL-40 cells was 22.19 μmol／L. Compared with the blank control group and NC group， the apoptotic rate increased and the healing rate decreased in the si-YKL-40 group， while the expression of YKL-40， MDR1 and Bcl-2 decreased， while the expression of Bax and caspase-3 increased （P＜0.05）. Conclusion Silencing YKL-40 can significantly increase the sensitivity of Ishikawa／DDP cell lines to cisplatin and promote cell apoptosis， which may be related to down-regulation of MDR1， Bcl-2 expression and up-regulation of Bax and caspase-3 expression.

Key words: Endometrial carcinoma, YKL-40, Cisplatin, Drug resistance