Abstract
Cancer-associated fibroblasts (CAFs) are associated with tumor progression and modulate drug sensitivity of cancer cells. However, the underlying mechanisms are often incompletely understood and crosstalk between tumor cells and CAFs involves soluble secreted as well as adhesion proteins. Interrogating a panel of non-small cell lung cancer (NSCLC) cell lines driven by EML4-ALK fusions, we observed substantial CAF-mediated drug resistance to clinical ALK tyrosine kinase inhibitors (TKIs). Array-based cytokine profiling of fibroblast-derived conditioned- media identified HGF-MET signaling as a major contributor to CAF-mediated paracrine resistance that can be overcome by MET TKIs. However, ‘Cell Type specific labeling using Amino acid Precursors’ (CTAP)-based expression and phosphoproteomics in direct coculture also highlighted a critical role for the fibronectin-integrin pathway. Flow cytometry analysis confirmed activation of integrin β1 (ITGB1) in lung cancer cells by CAF coculture. Treatment with pharmacological inhibitors, cancer cell-specific silencing or CRISPR-Cas9-mediated knockout of ITGB1 overcame adhesion protein-mediated resistance. Concurrent targeting of MET and integrin signaling effectively abrogated CAF-mediated resistance of EML4-ALK-driven NSCLC cells to ALK TKIs in vitro. Consistently, combination of the ALK TKI alectinib with the MET TKI capmatinib and/or the integrin inhibitor cilengitide was significantly more efficacious than single agent treatment in suppressing tumor growth using an in vivo EML4-ALK-dependent allograft mouse model of NSCLC. In summary, these findings emphasize the complexity of resistance-associated crosstalk between CAFs and cancer cells, which can involve multiple concurrent signaling pathways, and illustrate how comprehensive elucidation of paracrine and juxtacrine resistance mechanisms can inform on more effective therapeutic approaches.
Competing Interest Statement
R.C.D. is an employee and shareholder of Rain Oncology. He is a consultant to Guardant Health, received licensing fees for biologic materials from Takeda, ThermoFisher, Voronoi, Loxo, Black Diamond, Histocyte, Personal Genome Diagnostics, Inc., Roche, Casma Therapeutics and Foundation Medicine, and reports compensation for travel, accommodations or expenses from Pathos AI. E.B.H. serves on the advisory boards of Amgen, Janssen and Revolution Medicine, reports research funding from Revolution Medicines, and serves as a consultant for Ellipses, Kanaph Therapeutics, Inc. and ORI Capital II, Inc. J.M.K. reports research funding from Bristol-Myers Squibb unrelated to this project. All other authors declare that they have no competing financial interests.
