A proteomic study of hypoxia stress response on hepatocellular carcinoma in rat orthotopic liver transplantation model

Abstract

HCC is the second most prevalent cancer in Hong Kong and China.However, HCC has a high 3-year recurrence rate at 55% after surgery,which limits the long-term survival of HCC patients. One of theimportant variables in any surgical procedure is the organ ischemictime. Several studies had shown that hypoxic stress is an importantdeterminant in both malignant progression and ischemia-reperfusion.Herein, we postulate that hypoxia will result in proteomic expressionchanges in HCC tumors, thereby enhancing tumor recurrence and/orchemoresistance. Using our established orthotopic liver transplanta-tion model, we inoculated rat HCC cells via portal vein and allowedthe tumor growth for 3 weeks. For ischemic hypoxia experimentation,the HCC-bearing animals were operated and the hepatic artery wasclamped at designated time intervals of 0, 15, 30 and 45 minutes priorto harvesting the tumor (n = 5 for each time point). Sham controls(without clamping) of the tumor were also harvested at the respec-tive time points. HCC tissues were then subjected to 2-DE PAGEproteomic expression profiling analysis. Among the 1,200 spots iden-tified, about 50 spots demonstrated statistical significance in the timecourse of ischemia as analyzed by one-way ANOVA analysis (P <0.01). By linear regression analysis, we also identified protein speciesthat are associated with hypoxia stress response. Protein spots of interest are being identified using the MALDI-ToF/MS or MS/MSapproach.(supported by grant N_HKU 718/03)