Abstract LB-214: DNAJB1-PRKACA chimera increases Aurora kinase A expression in fibrolamellar hepatocellular carcinoma

Abstract

Abstract Purpose: Treatment of fibrolamellar hepatocellular carcinoma (FL-HCC), a rare liver cancer affecting the pediatric and adolescent population, is limited to surgical resection with no agents or therapeutic modalities available for unresectable disease. There has been recent interest in using Aurora kinase A (AURKA) inhibitors, with a clinical trial evaluating its efficacy in FL-HCC pending. Previously, we described a consistent single deletion of approximately 400 kB in chromosome 19 that results in a chimera between the heat shock protein DNAJB1 and the catalytic subunit of protein kinase A, PRKACA, in all FL-HCC tumor tissue studied. Furthermore, comparative ribonucleic acid sequence analysis has demonstrated that expression of AURKA, a regulator of cytokinesis and mitosis, is increased in FL-HCC tumor tissue compared with adjacent normal tissue. We hypothesize that the DNAJB1-PRKACA chimera is responsible for changes in AURKA expression in FL-HCC. Methods: The DNAJB1-PRKACA chimera was cloned into a lentiviral vector with a fluorescent reporter. Two stable cell lines (HeLa and a hepatocyte cell line, Huh-7) were transduced with a lentivirus containing either an empty multicloning site (control) or the DNAJB1-PRKACA chimera. Transduction was confirmed by the presence of a positive epifluorescent signal and immunoblots showing expression of the chimeric protein. Microarray data were evaluated for changes in AURKA expression while immunoblots were analyzed for the presence of AURKA in all transduced cells. Results: Microarray analysis showed an increase in AURKA transcripts in cells stably expressing the DNAJB1-PRKACA chimera. Compared to cells transduced with the control lentivirus, HeLa and Huh-7 cells transduced with the DNAJB1-PRKACA chimera demonstrated an increase in AURKA on immunoblots. Levels of a loading control, actin, were equivalent, indicating equal levels of protein examined between samples. Conclusion: Expression of the DNAJB1-PRKACA chimera results in an increase in AURKA. Upregulation of AURKA, in turn, may be responsible for subsequent tumor formation in FL-HCC. This finding further supports the DNAJB1-PRKACA chimera's role in the pathogenesis of FL-HCC and provides a potential therapeutic target for a disease that has no effective treatment besides surgery. Citation Format: Irene Isabel P. Lim, Emily A. Greene-Colozzi, Jennifer M. Murphy, Todd E. Heaton, Sanford M. Simon, Michael P. LaQuaglia. DNAJB1-PRKACA chimera increases Aurora kinase A expression in fibrolamellar hepatocellular carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-214. doi:10.1158/1538-7445.AM2015-LB-214