Abstract 1657: Microfluidics-based screening platform identifies a novel therapeutic approach to targeting EML4-ALK driven cancers

Abstract To achieve proliferative dysregulation, a hallmark of cancer, tumor cells utilize a variety of mechanisms to maintain constitutive oncogenic signaling in the absence of extracellular cues. One such mechanism occurs in cells expressing the EML4-ALK fusion protein. This fusion, found in about 4% of non-small cell lung cancer (NSCLC), is a result of an inversion within chromosome 2, placing the 3’ end of the ALK (anaplastic lymphoma kinase) gene downstream of the 5’ end of the EML4 (echinoderm microtubule associated protein-like 4) gene. The resulting fusion protein contains the oligomerization domain and additional disordered sequence elements of EML4 upstream of a functional ALK kinase domain. EML4-ALK is a critical driver for these tumors, promoting aberrant ALK-dependent oncogenic signaling. While tumors harboring the EML4-ALK fusion initially respond to ALK tyrosine kinase inhibitors (TKIs), resistance remains a significant clinical challenge requiring new therapeutic approaches. Recently, it has come to be understood that rather than responding through extracellular proliferative cues, the EML4-ALK fusion protein elicits constitutive ALK signaling through the formation of cytoplasmic biomolecular condensates. These condensates are the result of phase separation and have been shown to be causal for disease phenotypes in cell and animal models driven by EML4-ALK, establishing condensate modulation as a novel means by which to treat TKI-resistant tumors. Here, we have developed a novel proprietary microfluidics-based high throughput screening platform (termed PhaseScanTM) to identify small-molecule modulators of EML4-ALK condensates. Using this technology, we identified compounds that disrupt EML4-ALK condensates in vitro and in cells through a novel mechanism, distinct from that of known ALK TKIs, providing utility in both TKI-resistant as well as TKI-naïve tumors. Further profiling of the mechanism of action (MoA) revealed specific modification within the disordered region of EML4, disruption of EML4 oligomerization, and defective ALK signaling in cancer cells. Thus, our PhaseScanTM methodology enabled the identification of novel, functionally active chemical matter that would have otherwise been challenging to identify utilizing any conventional hit identification methodology. Citation Format: Richard C. Centore, Matthew Watson, Julia Doh, Jerome Cattin, Cinzia Sgambato, Amal Alex, Janhavi Sawant, Prathima Radhakrishnan, Jasmine Cornish, Alex Howarth, Nagakumar Bharatham, William E. Arter, Seema Qamar, Kadi L. Saar, Douglas Williamson, Andrew Seeber, Neils Groenewegen, Magdalena Czekalska, Tadas Kartanas, Niklas Ermann, Ahmed Taher, Tuomas Knowles, Shilpi Arora. Microfluidics-based screening platform identifies a novel therapeutic approach to targeting EML4-ALK driven cancers [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 1657.