The targeting of oncogenic 'driver' kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we analyzed tumor samples from a patient who initially responded to the ROS1 inhibitor crizotinib but eventually developed acquired resistance. In addition, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78. Previously described mechanisms of acquired resistance to tyrosine kinase inhibitors including target kinase-domain mutation, target copy number gain, epithelial-mesenchymal transition, and conversion to small cell lung cancer histology were found to not underlie resistance in the patient sample or resistant cell line. However, we did observe a switch in the control of growth and survival signaling pathways from ROS1 to EGFR in the resistant cell line. As a result of this switch, ROS1 inhibition-resistant HCC78 cells became sensitive to EGFR inhibition, an effect that was enhanced by co-treatment with a ROS1 inhibitor. Our results suggest that co-inhibition of ROS1 and EGFR may be an effective strategy to combat resistance to targeted therapy in some ROS1 fusion-positive NSCLC patients.
Bibliographical noteFunding Information:
D.L. Aisner has received honoraria from Abbott Molecular. P.A. Bunn Jr. has received consulting fees from Pfizer, Novartis, Genentech/Roche, AstraZeneca, Boehringer Ingelheim, Astellas, and GlaxoSmithKline. D.R. Camidge has received advisory board honoraria from Pfizer. R.C. Doebele has received research funding, consulting fees, and advisory board honoraria from Pfizer, honoraria from Abbott Molecular, consulting fees and advisory board honoraria from Boehringer Ingelheim, research funding from ImClone, and research funding from Eli Lilly. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.
ASJC Scopus subject areas
- General Biochemistry,Genetics and Molecular Biology
- General Agricultural and Biological Sciences