The sensitivity of digestive tract tumor cells to As2O3 is associated with the inherent cellular level of reactive oxygen species

AIM: To explore the correlation of the inherent cellular ROSlevel with the susceptibility of the digestive tract tumor cellsto apoptosis inducted by As2O3.METHODS: Two gastric carcinoma cell lines, SGC7901 andMKN45, and two esophageal carcinoma cell lines, EC/CUHK1 (alternatively named EC1. 71 ) and EC1867 with lowconcentration (2μmol@ L- 1)of As2O3 were cultured respectly,which confirmed the difference in apoptosis susceptibilitybetween SGC7901 and MKN45, and between EC/CUHK1 andEC1867. The cells were incubated withdihydrogenrhodamine123 (DHR123), used as a ROScapture, in absence of As2O3. The fluorescent intensity ofrhodamine123, which was the product of cellular oxidationof DHR123, was detected by flow cytometry, and ROS wasmeasured.RESULTS: Apoptosis induced by a low concentration ofAs2O3 was more readily to occur in SGC7901 (22.4% ± 2.4%)and EC/CUHK1 (27.0% ± 2.9%) than in MKN45 (2.1% ±0.5%) and EC1867(0.8% ± 0.5%). In other words, SGC7901was more sensitive than MKN45 to As2O3, meanwhile EC/CUHK1 was more sensitive than EC1867 to As2O3. The levelof inherent cellular ROS in SGC7901 (650 ± 37) was higherthan that in MKN45 (507 ± 22) ( P ＜ 0.01 ), and the level ofinherent cellular ROS in EC/CUHK1 (462 ± 17) was higherthan that in EC1867( 187 ± 12) ( P＜ 0.01).CONCLUSIONS: The cellular sensitivity to apoptosis inducedby As2O3 is associated with the difference in cellular ROSlevel. The inherent ROS level might determinate theapoptotic sensitivity of tumor cells to As2O3.