Comba, Andrea

Abstract Pancreatic cancer is a devastating malignancy in great need of new and more effective treatment approaches. In recent years, studies have indicated that nutritional interventions, particularly nutraceuticals, may provide novel avenues to modulate cancer progression. Here, our study characterizes the impact of ω-3 polyunsaturated fatty acids, eicosapentaenoic acid, and docosahexaenoic acid, as a nutraceutical intervention in pancreatic cancer using a genetically engineered mouse model driven by KrasG12D and Trp53R172H. This model closely resembles human pancreatic carcinogenesis, offering a disease relevant platform for translational research. Our findings showed that ω-3 polyunsaturated fatty acids intervention (using a diet supplemented with 6% cod liver oil) significantly reduced tumor volume as well as lung and liver metastasis and a trend toward improved survival rate compared with control treated mice. This antitumoral effect was accompanied by distinct changes in tumor membrane fatty acid profile and eicosanoids release. Furthermore, the eicosapentaenoic acid and docosahexaenoic acid intervention also reduced malignant histological parameters and induced apoptosis without affecting cell proliferation. Of note is the significant reduction in tumor fibrosis that was associated with decreased levels of Sonic Hedgehog, a major ligand controlling this cellular compartment in pancreatic cancer. All together our results demonstrate the impact of eicosapentaenoic acid and docosahexaenoic acid as antitumor regulators in pancreatic cancer, suggesting potential for ω-3 polyunsaturated fatty acids as a possible antitumoral dietary intervention. This research opens new avenues for integrating nutraceutical strategies in pancreatic cancer management.

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.