Ilyas, Sumera I.

Cholangiocarcinoma (CCA) is a lethal hepatobiliary neoplasm originating from the biliary apparatus. In humans, CCA risk factors include hepatobiliary inflammation and fibrosis. The recently identified interleukin (IL)−1 family member, IL‐33, has been shown to be a biliary mitogen which also promotes liver inflammation and fibrosis. Our aim was to generate a mouse model of CCA mimicking the human disease. Ectopic oncogene expression in the biliary tract was accomplished by the Sleeping Beauty transposon transfection system with transduction of constitutively active AKT (myr‐AKT) and Yes‐associated protein. Intrabiliary instillation of the transposon–transposase complex was coupled with lobar bile duct ligation in C57BL/6 mice, followed by administration of IL‐33 for 3 consecutive days. Tumors developed in 72% of the male mice receiving both oncogenes plus IL‐33 by 10 weeks but in only 20% of the male mice transduced with the oncogenes alone. Tumors expressed SOX9 and pancytokeratin (features of CCA) but were negative for HepPar1 (a marker of hepatocellular carcinoma). Substantive overlap with human CCA specimens was revealed by RNA profiling. Not only did IL‐33 induce IL‐6 expression by human cholangiocytes but it likely facilitated tumor development in vivo by an IL‐6–sensitive process as tumor development was significantly attenuated in Il‐6–/– male animals. Furthermore, tumor formation occurred at a similar rate when IL‐6 was substituted for IL‐33 in this model. Conclusion: The transposase‐mediated transduction of constitutively active AKT and Yes‐associated protein in the biliary epithelium coupled with lobar obstruction and IL‐33 administration results in the development of CCA with morphological and biochemical features of the human disease; this model highlights the role of inflammatory cytokines in CCA oncogenesis. (Hepatology 2015;61:1627–1642)

AbstractCholangiocarcinoma (CCA) is an aggressive biliary tract malignancy with limited treatment options and low survival rates. Currently, there are no curative medical therapies for CCA. Recent advances have enhanced our understanding of the genetic basis of this disease, and elucidated therapeutically relevant targets. Therapeutic efforts in development are directed at several key pathways due to genetic aberrations including receptor tyrosine kinase pathways, mutant IDH enzymes, the PI3K-AKT-mTOR pathway, and chromatin remodeling networks. A highly desmoplastic, hypovascular stroma is characteristic of CCAs and recent work has highlighted the importance of targeting this pathway via stromal myofibroblast depletion. Future efforts should concentrate on combination therapies with action against the cancer cell and the surrounding tumor stroma. As the mutational landscape of CCA is being illuminated, molecular profiling of patient tumors will enable identification of specific mutations and the opportunity to offer directed, personalized treatment options.

Abstract Reflux-induced injury promotes esophageal adenocarcinoma, one of the most rapidly increasing, highly lethal cancers in Western countries. Here, we investigate the efficacy of a combinatorial chemoprevention strategy for esophageal adenocarcinoma and characterize the underlying molecular mechanisms. Specifically, our approach involves the use of ursodeoxycholic acid (Urso) due to its ability to decrease injury-inducing bile salts in combination with Aspirin to mitigate the consequences of injury. We find that Urso-Aspirin combination reduces the risk of adenocarcinoma in vivo in animals with reflux, decreases the proliferation of esophageal adenocarcinoma cells, and downregulates a key cell cycle regulator, CDK2. Mechanistically, using cell growth, luciferase reporter, expression, and chromatin immunoprecipitation assays, we identify GLI1, a Hedgehog-regulated transcription factor, as a novel target of Urso-Aspirin combination. We show that GLI1 is upregulated during esophageal carcinogenesis, and GLI1 can bind to the CDK2 promoter and activate its expression. Although the Urso-Aspirin combination downregulates GLI1, the GLI1 overexpression not only abrogates the effect of this combination on proliferation but it also restores CDK-2 expression. These findings support that the chemopreventive effect of the Urso-Aspirin combination occurs, at least in part, through a novel GLI1-CDK2–dependent mechanism. To further understand the regulation of CDK2 by GLI1, both pharmacologic and RNAi-mediated approaches show that GLI1 is a transcriptional activator of CDK2, and this regulation occurs independent of Smoothened, the central transducer of the Hedgehog canonical pathway. Collectively, these results identify a novel GLI1-to-CDK2 pathway in esophageal carcinogenesis, which is a bona fide target for effective combinatorial chemoprevention with Urso and Aspirin. Cancer Res; 70(17); 6787–96. ©2010 AACR.