Proteomic analysis of differentially expressed proteins in human cholangiocarcinoma cells treated with Clonorchis sinensis excretory-secretory products.

Severe Clonorchis sinensis infection is a significant risk factor for malignant changes in bile ducts and surrounding liver tissues occurring as a result of direct contact with C. sinensis worms and their excretory-secretory products (ESP). However, the intrinsic molecular mechanisms involved in these processes remain obscure. To determine the effects of C. sinensis infection on protein expression in host bile duct epithelium, we examined proteomic profile changes in the human cholangiocarcinoma cell line (HuCCT1) treated with ESP at 24 h. Using a combination of 2-DE, quantitative image and MALDI-TOF MS analysis, we identified 83 proteins that were translationally modulated in response to ESP, among which 49 were up-regulated and 34 down-regulated. These proteins were classified under various biological categories, including metabolism, cell structure and architecture, proteolysis, protein modification, transport, signal transduction, and reactive oxygen species (ROS) detoxification. In particular, ESP induced the expression of redox-regulating proteins, including peroxiredoxins (Prdx 2, 3, and 6) and thioredoxin 1 (Trx 1), possibly via intracellular ROS generation. Application of the proteomic approach to identify ESP response proteins should be a prerequisite before further investigation to clarify the molecular pathways and mechanisms involved in C. sinensis infection of host cells.