Abstract PR05: Unique lipid metabolite profiling in BRAFV600E inhibitor drug-resistant melanoma and their potential as drug target

Abstract Melanoma is the most life-threatening skin cancer in the world. Advanced melanoma is highly metastatic, commonly develops drug resistance, and causes low survival rate in patients. PLX4032 (vemurafenib), a BRAFV600E inhibitor, is used to treat patients with late-stage melanoma. It showed initial good clinical responses but relapsed due to acquired drug resistance in tumors. The mechanism of PLX4032-induced resistance in melanoma is not well characterized; in particular, whether PLX4032-induced drug resistance in BRAF mutant melanoma would alter lipid metabolism in cancer is not clear. Understanding the status and role of lipid mediators (oxylipins) in melanoma pathology may be crucial for developing effective approach to overcome drug resistance. Our laboratory has demonstrated that plant sesquiterpene lactone deoxyelephantopin (DET) and its novel derivative DETD-35 effectively suppressed human A375 BRAFV600E melanoma with acquired drug resistance to PLX4032 in vitro and in xenograft mice. In this study we aimed to identify potential biomarkers associated with the resistant melanoma cells (A375-R) in the context of bioactive lipid mediators and to investigate whether DETD-35/DET effects against drug-resistant melanoma are through regulating their dynamics and contents. MS-based metabolomics was used to comprehensively analyze the oxylipin profiles in A375 and A375-R cells, mouse A375/A375-R tumor tissues, and respective sera with vehicle, drug, or compound treatment. We observed that PLX4032-resistant A375R melanoma cells or tumors produce significant and higher amounts of CYP450 enzyme-derived oxylipins than the parental A375, which were decreased after DETD-35 or DET treatment. This study proposes a role of CYP450-derived oxylipins in PLX4032-resistant melanoma cells and its potential to be a drug target. This abstract is also being presented as Poster B03. Citation Format: Meng-Ting Chang, Jia-Hua Feng, Kyoko Nakagawa-Goto, Kuo-Hsiung Lee, Lie-Fen Shyur. Unique lipid metabolite profiling in BRAFV600E inhibitor drug-resistant melanoma and their potential as drug target [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR05.