The Correlation between the Inhibiting Effects of Irinotecan on Colorectal Cancer Cell Proliferation and ATP -sensitive Potassium Channel / 中国医科大学学报

ABSTRACT

Objective To study the effects of Irinotecan (CPT-11) on human colorectal cancer HCT-116 and HT-29 cells and investigate the potential mechanisms.Methods The effect of Irinotecan on the proliferation of HCT-116 and HT-29 cells was determined by MTT assays.The invasive capacity was measured by transwell assays,and the apoptosis of the tumor cells was detected by flow cytometry after stained with Annexin-V and PI.The difference between the current of ATP-sensitive potassium ion of HCT-116 and HT-29 was examined by patch clamp.Results It was found that 1.0-64.0 μg/ml CPT-11 could inhibit the proliferation and the invasive capacity of HCT-116 and HT-29 cells at both dose-and time-dependent manner.The IC_(50) of HCT-116 and HT-29 were 39.3 and 19.5 μg/ml respectively.Cytometry showed that the apoptotic rates were increased from 14.8% and 9.3% to 36.9% and 27.9% after the treatment of 32.0 μg/ml and 16.0 μg/ ml CPT-11,which were close to their IC_(50).The proportion of G_0/G_1 and S of HCT-116 and HT-29 was enhanced from 27.4% and 17.4% to 95.9% and 98.2%.Transwell assay indicated that the invasiveness of HCT-116 and HT-29 was reduced by 40.8% and 47.5%.The patch clamp showed that CPT-11 reduced the I_(KATP) of cell membrane at a negative dose-dependent manner.Conclusion CPT-11 could have a significant impact on the proliferation,invasiveness,cell cycle,and the apoptosis of human colorectal cancer cell HCT-116 and HT-29.HT-29 was more sensitive to CPT-11 than HCT-116.The inhibitory effect of CPT-11 on cell proliferation might be linked to its inhibition of ATPsensitive potassium channel.