Abstract A94: Understanding of differing sensitivity in EML4-ALK NSCLC patients to crizotinib and geldanamycin.

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, afflicting nearly 200,000 people in the United States each year. Abnormal ALK is found in about 5% of NSCLC cases, meaning more than 5,000 new patients could benefit from the tyrosine kinase inhibitor (TKI) crizotinib. However, not all patients benefit from such treatment, with the clinical response to crizotinib differing among patients who harbor the same molecular abnormality. Similarly, patients with ALK fusion proteins have shown varying sensitivity to the HSP90 inhibitor geldanamycin in preclinical studies. We have chosen two NSCLC cell lines, H3122 and H2228, as a model to address these questions. Both cell lines harbor EML4-ALK fusions with differing sensitivity to the inhibitors crizotinib and geldanamycin. We used the established method of TMT peptide labeling coupled with serial peptide immunoprecipitation. To observe the effects of crizotinib and geldanamycin on ALK sensitive H3122 and non-sensitive H2228 NSCLC cell lines quantitative analysis was performed. Phosphotyrosine, acetylation, methylation, ATM/ATR substrate (s/tQ), Akt/AMPK subs AGC/CAMK/STE, and MAPK family kinase motif antibodies were used for immunoprecipitation allowing us to characterize and quantify post translational modifications before and after treatment. In this study, we identify extensive signaling networks downstream of ALK across multiple spaces, including phosphorylation, acetylation, and methylation. These differences may be clinically significant and highlight the possibility that ALK inhibitors alone may only be effective in a subset of NSCLC ALK-positive patients with EML4-ALK inversion. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A94. Citation Format: Klarisa Rikova, Benjamin Hall, Anthony Possemato, Keri Mroszczyk, Kimberly A. Lee, Joan MacNeill, Jian Min Ren, Ailan Guo, Daniel Mulhern, Yi Wang, Sean A. Beausoleil, Michael J. Comb. Understanding of differing sensitivity in EML4-ALK NSCLC patients to crizotinib and geldanamycin. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A94.