A Drug Resistance Screen Using a Selective MET Inhibitor Reveals a Spectrum of Mutations That Partially Overlap with Activating Mutations Found in Cancer Patients

Abstract

The emergence of drug resistance is a primary concern in any cancer treatment, including with targeted kinase inhibitors as exemplified by the appearance of Bcr-Abl point mutations in chronic myeloid leukemia (CML) patients treated with imatinib. In vitro approaches to identify resistance mutations in Bcr-Abl have yielded mutation spectra that faithfully recapitulated clinical observations. To predict resistance mutations in the receptor tyrosine kinase MET that could emerge during inhibitor treatment in patients, we conducted a resistance screen in BaF3 TPR-MET cells using the novel selective MET inhibitor NVP-BVU972. The observed spectrum of mutations in resistant cells was dominated by substitutions of tyrosine 1230 but also included other missense mutations and partially overlapped with activating MET mutations that were previously described in cancer patients. Cocrystallization of the MET kinase domain in complex with NVP-BVU972 revealed a key role for Y1230 in binding of NVP-BVU972, as previously reported for multiple other selective MET inhibitors. A second resistance screen in the same format with the MET inhibitor AMG 458 yielded a distinct spectrum of mutations rich in F1200 alterations, which is consistent with a different predicted binding mode. Our findings suggest that amino acid substitutions in the MET kinase domain of cancer patients need to be carefully monitored before and during treatment with MET inhibitors, as resistance may preexist or emerge. Compounds binding in the same manner as NVP-BVU972 might be particularly susceptible to the development of resistance through mutations in Y1230, a condition that may be addressed by MET inhibitors with alternative binding modes. Cancer Res; 71(15); 5255-64. Ó2011 AACR.

Glesatinib Exhibits Antitumor Activity in Lung Cancer Models and Patients Harboring MET Exon 14 Mutations and Overcomes Mutation-mediated Resistance to Type I MET Inhibitors in Nonclinical Models

“…Interestingly, the MET L1195V and F1200L/I mutations that were associated with resistance to both inhibitor classes in MET-mutant variant enzyme screens and/or resistance studies occur distal from the ligand binding site of type I inhibitors and may result in enhanced substrate affinity or destabilization of the autoinhibited A-loop conformation. Consistent with the observed resistance, biochemical screens in the current studies indicated a 10-fold loss of activity for crizotinib for MET F1200I compared with WT and this was the same amino acid that was found mutated in a crizotinib drug resistance screen (39). Although the MET F1200I mutation did not emerge as an acquired resistance mechanism during glesatinib drug resistance screens, there is direct involvement of this residue in the type II DFG-out binding mode, which would provide a clear molecular basis for attenuated activity for glesatinib and other type II inhibitors and is consistent with the 4-fold decrease in potency in crizotinib-resistant cells that harbored the Y1230H/F1200L double mutation.…”

The Selective Intravenous Inhibitor of the MET Tyrosine Kinase SAR125844 Inhibits Tumor Growth inMET-Amplified Cancer

“…Although not yet documented in cancer patients but described in in vitro cell systems (42,43), mutations will probably emerge due to an acquired resistance to MET kinase inhibitors. We characterized the activity of SAR125844 on 6 MET mutant variants, including H1094Y, L1195V, Y1230H variant, responsible of resistance to type I MET selective inhibitors, and M1250T and D1228H variants that have equivalent mutations in RET and KIT kinase domains.…”

The HSP90 Inhibitor Ganetespib Synergizes with the MET Kinase Inhibitor Crizotinib in both Crizotinib-Sensitive and -Resistant MET-Driven Tumor Models

“…Thus, although crizotinib can inhibit the activity of most MET mutants, some constitutively active mutants, including MET-L1213V and -Y1248H, are resistant to this inhibitor (12,14). Additional studies have suggested that these mutations not only mediate primary resistance to MET inhibitors but may also play a role in acquired resistance to MET-TKI (15)(16)(17).…”