Abstract
<div>AbstractPurpose:<p>Treatment with <i>KRAS</i><sup>G12C</sup> inhibitors such as sotorasib can produce substantial regression of tumors in some patients with non–small cell lung cancer (NSCLC). These patients require alternative treatment after acquiring resistance to the inhibitor. The mechanisms underlying this acquired resistance are unclear. The purpose of this study was to identify the mechanisms underlying acquired sotorasib resistance, and to explore potential treatments for rescuing patients with sotorasib-resistant <i>KRAS</i><sup>G12C</sup> NSCLC cells.</p>Experimental Design:<p>Clones of sotorasib-sensitive <i>KRAS</i><sup>G12C</sup> NSCLC H23 cells exposed to different concentrations of sotorasib were examined using whole-genomic transcriptome analysis, multiple receptor kinase phosphorylation analysis, and gene copy-number evaluation. The underlying mechanisms of resistance were investigated using immunologic examination, and a treatment aimed at overcoming resistance was tested <i>in vitro</i> and <i>in vivo</i>.</p>Results:<p>Unbiased screening detected subclonal evolution of <i>MET</i> amplification in <i>KRAS</i><sup>G12C</sup> NSCLC cells that had developed resistance to sotorasib <i>in vitro</i>. MET knockdown using small interfering RNA (siRNA) restored susceptibility to sotorasib in these resistant cells. MET activation by its amplification reinforced RAS cycling from its inactive form to its active form. In addition to RAS-mediated MEK–ERK induction, MET induced AKT activation independently of RAS. Crizotinib, a MET inhibitor, restored sensitivity to sotorasib by eliminating RAS–MEK–ERK as well as AKT signaling. MET/<i>KRAS</i><sup>G12C</sup> dual inhibition led to tumor shrinkage in sotorasib-resistant xenograft mice.</p>Conclusions:<p><i>MET</i> amplification leads to the development of resistance to <i>KRAS</i><sup>G12C</sup> inhibitors in NSCLC. Dual blockade of MET and <i>KRAS</i><sup>G12C</sup> could be a treatment option for <i>MET</i>-amplified, <i>KRAS</i><sup>G12C</sup>-mutated NSCLC.</p></div>
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