Abstract 4548: Discovering novel ALK-lung carcinoma therapeutic strategies by identifying combinations with Alectinib from ALK-positive lung carcinoma cell lines

Abstract Background: The therapeutic landscape for chromosomally rearranged anaplastic lymphoma kinase (ALK) has focused on the development of Tyrosine-kinase inhibitors (TKI) that specifically target ALK activity. However, as patients progress on first- and second line TKIs, over 50% of resistance is due to non-mutational resistance via compensatory pathways, also known as ALK-non dominant resistance. Alterations in other drivers such as EGFR, KRAS, MET account for some of the resistance mechanisms. Thus, here we explore the therapeutic activity of drug combinations that pair an ALK inhibitor with a drug that targets a "second driver". We describe our high-throughput drug screening platform that combines Alectinib, a selective blocker of ALK, with a panel of hundreds of chemical compounds curated to be active against a diverse array of pathways involved in cellular functions dysregulated in cancer. In this work, we identified several synergistic combinations that further increased the sensitivity of five ALK-positive lung cancer cell lines (DFCI 032, NCI-H3122, NCI-H2228, SNU2535, SNU324) to Alectinib in comparison to single treatment with the final goal of targeting resistance, before it emerges. Methods: ALK-positive cancer cell sensitivity to different compounds was assessed by generating the IC50 curves in the presence and absence of Alectinib. Cells were characterized by bulk-RNAseq, bulk-DNA seq, Reverse-phase protein array, and Mass spectrometry to identify perturbed RNA pathways, DNA mutations, and proteome alterations. Results: In this study, we present for the first time, a group of compounds, such as Gilteritinib, Trametinib, Dinaciclib, WYE-125132, Cenisertib, SN-38 which exhibit the capacity to induce cytotoxic effects in ALK-positive lung cancer cells, when combined with Alectinib. Our findings demonstrate a novel sensitivity of ALK driven by non-conventional parallel signaling, apart from conventional targets previously described, such as phosphoinositol-3kinase (PI3K)/Akt, signal transducer and activator of transcription 3 (STAT3), and extracellular signal-regulated kinases (ERK). Conclusions: Through the integration of different multiomic approaches on five ALK-positive lung cancer cell lines, we have pinpointed a novel role of MAPK, CDK, and mTOR, pathways and their regulators, as a promising avenue for advancing treatment strategies for ALK-positive lung cancer. These findings, along with the identification of several other significant targetable elements illustrate a new approach towards the discovery of new drug combinations and targetable pathways to tackle ALK TKI resistance in ALK-positive patients before it emerges. We have previously generated Alectinib-resistant models and are in the process of screening to identify any resistant pathways that may align with those identified in the sensitive lines. Citation Format: Hamadi Madhi, Habib Serhan, Nathalie M. Vandecan, Zhaoping Qin, Albert Liu, Aaron Udager, Sofia D. Merajver, Matthew B. Soellner, Nathan Merrill. Discovering novel ALK-lung carcinoma therapeutic strategies by identifying combinations with Alectinib from ALK-positive lung carcinoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4548.