Molecular changes associated with acquired resistance to crizotinib in ROS1-rearranged non-small cell lung cancer (NSCLC)
Menée sur des lignées cellulaires et à l'aide d'échantillons tumoraux prélevés sur deux patients atteints d'un cancer du poumon non à petites cellules avec réarrangement ROS1, cette étude met en évidence une hétérogénéité des anomalies moléculaires associées à une résistance au crizotinib
Purpose: Although ROS1-rearranged NSCLC is sensitive to crizotinib, development of resistance is inevitable. Here, we identified molecular alterations in crizotinib-resistant tumors from two NSCLC patients with the CD74-ROS1 rearrangement, and in HCC78 cells harboring SLC34A2-ROS1 that showed resistance to crizotinib (HCC78CR cells). Experimental Design: ROS1 kinase domain mutations were examined in fresh tumor tissues from two NSCLC patients and HCC78CR1-3 cells by direct sequencing. Ba/F3 cells expressing ROS1 secondary mutations were constructed to evaluate resistance to crizotinib. Up-regulated pathway was identified using phospho-receptor tyrosine kinase array, EGFR signaling antibody arrary, and RNA sequencing (RNA-seq). Cell proliferation and ROS1 downstream signaling pathways were compared between HCC78 and HCC78CR1-3 cells. Results:The ROS1 G2032R mutation was identified in crizotinib-resistant tumors from one patient. Furthermore, HCC78CR1 and CR2 cells harbored a novel ROS1 L2155S mutation (73.3% and 76.2%, respectively). ROS1 G2032R and L2155S mutations conferred resistance to crizotinib in Ba/F3 cells. Evidence of epithelial-to-mesenchymal transition with down-regulated E-cadherin and up-regulated vimentin was observed in HCC78CR1-2 cells and in the other patient. RNA-seq and EGFR signaling antibody array revealed that the EGFR pathway was significantly up-regulated in HCC78CR3 versus HCC78 cells. Cells with the ROS1-mutation and up-regulated EGFR were sensitive to foretinib, an inhibitor of c-MET, VEGFR2, and ROS1 and irreversible EGFR tyrosine kinase inhibitors plus crizotinib, respectively. Conclusions:Molecular changes associated with acquired crizotinib resistance in ROS1-rearranged NSCLC are heterogeneous including ROS1 tyrosine kinase mutations, EGFR activation, and epithelial-to-mesenchymal transition.