Abstract 5027: Targeting ARAF p.S214C mutation with sorafenib in non-small cell lung cancer

Abstract

Abstract Sorafenib is an FDA-approved multi-kinase inhibitor for the treatment of several cancer types, but is still under investigation for non-small cell lung cancer (NSCLC). Although sorafenib has not shown significant survival benefit in clinical trials for NSCLC patients, one study identified a patient with advanced lung adenocarcinoma harboring ARAF p.S214C mutation as an exceptional sorafenib responder. As NSCLC lacks clinically validated predictive biomarkers for drug responses, we aim to evaluate the potential of ARAF p.S214C mutation as a biomarker for sorafenib sensitivity and its mechanism of action. Constructs with ARAF p.S214C mutation, ARAF-wild type (WT) and EGFR-vector control were ectopically expressed in a lung adenocarcinoma cell line, H2023, by retroviral transduction. Western blot confirmed stable overexpression of ARAF proteins over time. MTT assay showed that sorafenib inhibited growth of cells expressing ARAF p.S214C more pronouncedly than cells expressing ARAF-WT or vector control. In addition, spheroids formed by cells expressing ARAF p.S214C were more sensitive to sorafenib inhibition, indicating sorafenib sensitivity of ARAF p.S214C in NSCLC in vitro. To evaluate whether such sorafenib sensitivity is dependent on the kinase activity of ARAF, phospho-MEK and MAPK levels in mutant cells will be determined. As ARAF belongs to the Raf protein family which also includes BRAF and RAF1, knockdown studies and co-immunoprecipitation will be performed to determine whether BRAF and RAF1 are essential for ARAF p.S214C activity. The in vivo sorafenib sensitivity of ARAF p.S214C will be validated in tumor xenografts established from cells expressing the above constructs upon sorafenib treatment. Tumor volume will be assessed and expression of the tumor marker cytokeratin will be evaluated by immunohistochemistry. This study may reveal ARAF p.S214C as a potential biomarker for sorafenib sensitivity and a new target for precision medicine in NSCLC. Citation Format: Carol Lee, Sze Man Chan, Sai Fung Yeung, Stephen Kwok-Wing Tsui. Targeting ARAF p.S214C mutation with sorafenib in non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5027.