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Aurora kinases are over-expressed in a variety of cancers and strategies targeting aurora kinases are intensively studied as potential anti-cancer treatment. In this study we sought to explore the expression pattern of auroraB kinase in biliary tract carcinoma and the potential of using aurora kinase inhibition for the treatment of biliary tract carcinoma, which is resistant to most conventional cytotoxic agents. Archival tumor tissue was obtained from patients who underwent operation as an attempt of definitive treatment. Immunohistochemical staining with rabbit anti-auroraB kinase antibody (NB100-294, Novus) was used to evaluate the extent of nuclear staining. We tested the growth-inhibitory effect of VE-465, a small-molecule aurora kinase inhibitor provided by Merck, in a biliary tract carcinoma cell line HuCCT1. Cell viability was measured by trypan blue staining. Protein expression was evaluated by western blotting and immunocytochemistry. DNA content and apoptosis were measured by flow cytometry. A total of 162 patients with biliary tract carcinoma (74 intrahepatic cholangiocarcinoma, 49 extrahepatic bile duct carcinoma, and 39 gallbladder carcinoma) were evaluated. Nuclear expression of auroraB kinase, defined as moderate to strong nuclear staining in more than 10% of tumor cells, was found in 45 (27.8%) patients, including 19 of 64 stage I/II disease and 26 of 98 stage III/IV disease (p = 0.66). The median overall survival for patients with and without nuclear expression of auroraB kinase was 11.4 months and 17.7 months, respectively (p=0.03) Multi-variate analysis indicated that tumor stage and nuclear expression of auroraB kinase were significant prognostic factor (p < 0.001 and p= 0.022, respectively). Aurora B kinase was found to be over-expressed in the nuclei of HuCCT1 cells. VE-465 inhibited cell growth to < 20% of control and inhibited histone H3 phosphorylation in HuCCT1 cells at concentrations of 0.1 microM or higher. Flow cytometry disclosed G2/M arrest and formation of 8n cells after VE-465 treatment in a dose- and time-dependent manner. VE-465 can potentiate apoptosis induced by paclitaxel when given after, but not before, paclitaxel. This effect was not seen when VE-465 was given along with oxaliplatin or 5-FU. Our data indicate that nuclear expression of auroraB kinase may be associated with poorer survival, independent of tumor stage, for patients with biliary tract carcinoma. Aurora kinase inhibitors may be effective therapeutic agents for biliary tract carcinoma. The interaction between cytotoxic agents and aurora kinase inhibitors may depend on the mechanisms of cytotoxic agents and sequence of administration. (supported by grant DOH94-TD-B-111-001, 95R0066-BM-1-02, and NHRI-CN-CA0201S(95A070) )

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA