Effect of proteasome inhibitor Oprozomib on ovarian cancer cells to cis-platinum

Fang-Fang REN, Tai-Qiang ZHAO
2020 Medical Journal of Chinese People's Liberation Army  
Objective To study the enhancement of sensitivity to cisplatin (DDP) mediated by the addition of proteasome inhibitor Oprozomib (OZ) in ovarian cancer cells. Methods SKOV3/DDP and A2780/DDP cells were cultured in vitro, and the logarithmic growth phase cells were used in this study. To study the effect of OZ on drug-resistant cell viability, a series dilutions of OZ (0, 3, 9, 27, 81, 243, 729, 2181, and 6561 nmol/L) was used. The effect of DDP was also investigated with a series titrations (0,
more » ... ies titrations (0, 3, 9, 27, 81, 243, 729, 2181 and 6561 nmol/L) in the presence of 50 μl of 500 nmol/L OZ. CCK-8 method was used to detect cell viability; flow cytometry was used to detect the apoptosis rate after treated with DDP+OZ. The experiments were divided into the control group and OZ group to detect the effects of OZ on the activity of proteasome chymotrypsin (CT-L), the synthesis of intracellular glutathione (GSH); the expression of intracellular glutathione synthetase (GSS) was examined using western blotting. The experiments were divided into the control group, DDP group, OZ group, DDP+OZ group, DDP+OZ+GSH group and DDP+OZ+Tempol group to detect the ROS level and apoptosis rate. Results The IC50 of OZ to SKOV3/DDP and A2780/DDP cells were 140 and 350 nmol/L, respectively; In the presence of OZ, the IC50 of DDP to SKOV3/DDP and A2780/DDP cells were 154 and 232 nmol/L, respectively. The apoptosis rate of ovarian cancer cells increased significantly (P<0.01) after treated with DDP+OZ together. OZ can inhibit the CT-L activity of the proteasome in a dose-dependent manner and can inhibit GSH synthesis and GSS protein expression (P<0.01). The decrease of GSH level leads to the obstruction of ROS clearance, and the ROS level was significantly reduced by the ROS scavenger Tempol (P<0.05, P<0.01). Tempol significantly inhibits the apoptosis induced by DDP+OZ (P<0.01). Conclusion OZ enhanced sensitivity of SKOV3/DDP and A2780/DDP to cis-platinum by inhibiting the generation of GHS which resulted in the accumulation of ROS. DOI: 10.11855/j [...]
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