Sarver, Aaron L.

Abstract Hepatic steatosis is a strong risk factor for the development of hepatocellular carcinoma (HCC), yet little is known about the molecular pathology associated with this factor. In this study, we performed a forward genetic screen using Sleeping Beauty (SB) transposon insertional mutagenesis in mice treated to induce hepatic steatosis and compared the results to human HCC data. In humans, we determined that steatosis increased the proportion of female HCC patients, a pattern also reflected in mice. Our genetic screen identified 203 candidate steatosis-associated HCC genes, many of which are altered in human HCC and are members of established HCC-driving signaling pathways. The protein kinase A/cyclic AMP signaling pathway was altered frequently in mouse and human steatosis-associated HCC. We found that activated PKA expression drove steatosis-specific liver tumorigenesis in a mouse model. Another candidate HCC driver, the N-acetyltransferase NAT10, which we found to be overexpressed in human steatosis–associated HCC and associated with decreased survival in human HCC, also drove liver tumorigenesis in a steatotic mouse model. This study identifies genes and pathways promoting HCC that may represent novel targets for prevention and treatment in the context of hepatic steatosis, an area of rapidly growing clinical significance. Cancer Res; 77(23); 6576–88. ©2017 AACR.

Abstract Progression from adenoma to colon cancer is a multi-step process and the role of microRNAs in this transformation is not completely understood. We used both in vitro and in vivo approaches to demonstrate the role of miRNAs in the transformation of adenoma to adenocarcinoma. Reporter assays were used to show the direct interaction of miRNAs to target gene. A Tet-inducible TripZ system and miRzips constructs were used in the in vitro function and xenograft studies. Kaplan-Meier survival curves and Cox regression were used to analyze the survival data in colon cancer patients. Here, we show that the combination of miR-503 and miR-182 contributes to the transformation of colon adenoma to adenocarcinoma by cooperatively regulating the tumor suppressor gene, FBXW7. We found that miR-182 was upregulated in both colon adenoma and adenocarcinoma, whereas miR-503 was upregulated only in adenocarcinoma, indicating a potential hierarchical and stepwise expression of these miRNAs in the regulation of FBXW7. Furthermore, we showed that colon adenoma derived non-tumorigenic AAC1 cells were transformative and tumorigenic in mice when expressing Tet-inducible miR-503. Finally, the combination of miR-503 and miR-182 transcript levels was predictive of poor outcome in colon cancer patients. We conclude that a step-wise expression of miR-182 and miR-503 in benign adenoma synergistically regulates the driver gene FBXW7, thus contributing to the progression of colon adenoma to adenocarcinoma. Citation Format: Lihua Li, Aaron Sarver, Rohini Khatri, Praveensingh Hajeri, Iris Kamenev, Stephen Thibodeau, Clifford J. Steer, Subbaya Subramanian. MicroRNAs miR-503 and -182 regulate FBXW7 contributing to the malignant transformation to colon adenocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4368. doi:10.1158/1538-7445.AM2014-4368

AbstractGenetic changes in colon cancer are known to parallel the tissue abnormalities associated with the disease, namely adenoma and adenocarcinoma. The role of microRNA dysregulation in dysplastic progression, however, is not well understood. Here, we show that miR‐182 and miR‐503 undergo sequential up‐regulation and drive the progression of colon adenoma to adenocarcinoma by cooperatively down‐regulating the tumour suppressor FBXW7. We identified that increased expression of miR‐182 is a feature of adenomas. A subsequent increase in miR‐503 expression works cooperatively with miR‐182 to induce transformation of an adenoma to adenocarcinoma. We show that introducing miR‐503 into AAC1 cells, which are derived from a benign adenoma, confers tumourigenic potential. We also demonstrated that blocking both miR‐182 and miR‐503 in HCT116 colon cancer cells resulted in increased FBXW7 expression and significantly reduced tumour size in xenograft models. We confirmed relevance of these results in patients by examining the expression levels of miR‐182 and miR‐503 in over 200 colon cancer patients with 12 year survival outcome data. Decreased patient survival was correlated with elevated expression of both miRNAs, suggesting that elevated levels of both miR‐182 and miR‐503 define a novel prognostic biomarker for colon cancer patients. In conclusion, we show that a sequential expression of miR‐182 and miR‐503 in benign adenoma cooperatively regulates the tumour suppressor FBXW7, contributing to the malignant transformation of colon adenoma to adenocarcinoma and miR‐182 and miR‐503 may prove to be novel therapeutic targets. Array data are available at: http://www.oncomir.umn.edu/ Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd

Abstract With recent approval of the first dendritic cell (DC) vaccine for patient use, many other DC vaccine approaches are now being tested in clinical trials. Many of these DC vaccines employ tumor cell lysates (TL) generated from cells cultured in atmospheric oxygen (∼20% O2) that greatly exceeds levels found in tumors in situ. In this study, we tested the hypothesis that TLs generated from tumor cells cultured under physiologic oxygen (∼5% O2) would be more effective as a source for DC antigens. Gene expression patterns in primary glioma cultures established at 5% O2 more closely paralleled patient tumors in situ and known immunogenic antigens were more highly expressed. DCs treated with TLs generated from primary tumor cells maintained in 5% O2 took up and presented antigens to CD8 T cells more efficiently. Moreover, CD8 T cells primed in this manner exhibited superior tumoricidal activity against target cells cultured in either atmospheric 20% O2 or physiologic 5% O2. Together, these results establish a simple method to greatly improve the effectiveness of DC vaccines in stimulating the production of tumoricidal T cells, with broad implications for many of the DC-based cancer vaccines being developed for clinical application. Cancer Res; 71(21); 6583–9. ©2011 AACR.