Abstract
Abstract Intrinsic and acquired resistance to anti-EGFR antibody therapy, frequently mediated by mutant or amplified KRAS oncogene, is a significant challenge in the treatment of colorectal cancer (CRC), the second-leading cause of cancer-related death in the United States. However, the mechanism of KRAS-mediated therapeutic resistance is not well understood. In this study, we found that clinically used anti-EGFR antibodies, including cetuximab and panitumumab, induce killing of sensitive CRC cells through p73-dependent transcriptional activation of the pro-apoptotic Bcl-2 family protein PUMA. Inhibition of EGFR and downstream AKT by cetuximab and panitumumab promotes Tyr99 phosphorylation of p73, which then binds to PUMA promoter to activate its transcription, resulting in cell death via the mitochondrial pathway. PUMA induction and p73 phosphorylation are abrogated in CRC cells with acquired resistance to anti-EGFR antibodies due to KRAS alterations and residual AKT activity. Upon screening a panel of anticancer drugs, we found that inhibition of aurora kinases preferentially kills mutant KRAS CRC cells. A combination with aurora kinase inhibitor overcomes KRAS-mediated resistance to anti-EGFR antibodies in vitro and in vivo by restoring PUMA induction and eliminating the residual AKT activity. Collectively, our results suggest that p73-dependent PUMA induction plays a critical role in mediating the sensitivity of CRC cells to anti-EGFR antibodies, and that restoration of PUMA induction and apoptosis is a promising approach to improve the efficacy of EGFR-targeted therapy. Citation Format: Kyle Knickelbein, Jingshan Tong, Dongshi Chen, Yi-Jun Wang, Sandra Misale, Alberto Bardelli, Jian Yu, Lin Zhang. PUMA induction by p73 mediates response and resistance of colorectal cancer to anti-EGFR antibody therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2861.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
