Brusatol enhances the chemotherapy efficacy of Cisplatin and Gemcitabine in KKU-100 cholangiocarcinoma cells through ROS-mediated apoptosis.

One of the main obstacles in Cholangiocarcinoma (CCA) treatment is drug resistant to the standard therapy, Cisplatin combined with Gemcitabine (Cis/Gem). Brusatol (Bru) has shown its potential in enhancing the effects of other chemotherapeutic drugs. Therefore, this study investigates the anti-cancer effects of Bru alone or combined with chemotherapeutic drugs, Cis and Gem, in human CCA cells (KKU-100), and explores the underlying mechanisms. Cell viability was determined using MTT assay, while intracellular reactive oxygen species (ROS) levels were measured using a DCFDA fluorescence assay. Apoptosis was assessed by caspase-3, -8, and -9 activity and annexin-V-FITC/propidium iodide (PI) double staining. Mitochondrial membrane potential (ΔΨm) was detected by JC-1 staining. Combination of Bru and Cis or Gem increased intracellular ROS levels, caspase-3, -8, and -9 activities, apoptotic cell population and the loss of ΔΨm in KKU-100 cells. This indicated the enhanced apoptotic effects of the combination therapy through the activation of both intrinsic and extrinsic pathways. Additionally, combination of Bru with Cis or Gem significantly reduced colony formation, and suppressed cell migration and invasion in KKU-100 cells. These findings support the potential of Bru as a promising anti-cancer agent or adjunct therapy to enhance current chemotherapy in CCA treatment.