Single and Dual Targeting of Mutant EGFR with an Allosteric Inhibitor

Abstract

Allosteric kinase inhibitors offer a potentially complementary therapeutic strategy to ATP-competitive kinase inhibitors due to their distinct sites of target binding. In this study, we identify and study a mutant-selective EGFR allosteric inhibitor, JBJ-04-125-02, which as a single agent can inhibit cell proliferation and EGFR L858R/T790M/C797S signaling in vitro and in vivo . However, increased EGFR dimer formation limits treatment effi cacy and leads to drug resistance. Remarkably, osimertinib, an ATP-competitive covalent EGFR inhibitor, uniquely and signifi cantly enhances the binding of JBJ-04-125-02 for mutant EGFR. The combination of osimertinib and JBJ-04-125-02 results in an increase in apoptosis, a more effective inhibition of cellular growth, and an increased effi cacy in vitro and in vivo compared with either single agent alone. Collectively, our fi ndings suggest that the combination of a covalent mutant-selective ATP-competitive inhibitor and an allosteric EGFR inhibitor may be an effective therapeutic approach for patients with EGFR -mutant lung cancer. SIGNIFICANCE:The clinical effi cacy of EGFR tyrosine kinase inhibitors (TKI) in EGFR -mutant lung cancer is limited by acquired drug resistance, thus highlighting the need for alternative strategies to inhibit EGFR. Here, we identify a mutant EGFR allosteric inhibitor that is effective as a single agent and in combination with the EGFR TKI osimertinib.

Mutant‐Selective Allosteric EGFR Degraders are Effective Against a Broad Range of Drug‐Resistant Mutations

“…During our PROTACs development process, we identified JBJ‐04‐125‐02 (Figure B), an allosteric inhibitor with a 2‐hydroxy‐5‐fluorophenyl group with improved potency, including the ability to inhibit cell proliferation of Ba/F3 cells as a single agent . Therefore, in addition to DDC‐01‐163, we synthesized and tested JBJ‐04‐125‐02‐based allosteric EGFR degraders.…”

“…DDC‐01‐163 potently inhibited the proliferation of L858R/T790M mutant EGFR Ba/F3 cells (EC 50 =0.096 μ m ) while sparing the wildtype EGFR Ba/F3 cells (EC 50 >10 μ m ; Figure C and S2). This striking mutant‐selectivity likely arises primarily from the parent allosteric inhibitor scaffold . Interestingly, DDC‐01‐163 was 51‐fold more potent than its parent allosteric EGFR inhibitor, JBJ‐07‐149 (0.096 μ m vs. 4.9 μ m ) in cellular assays, despite being 45‐fold less potent than JBJ‐07‐149 in biochemical assays.…”

“…Inspired by recent studies showing that combination treatment with allosteric EGFR inhibitor JBJ‐04‐125‐02 and ATP‐site inhibitor osimertinib could enhance apoptosis and delay onset of drug resistance, we examined whether dual modulation of EGFR using an allosteric PROTAC and an ATP‐site inhibitor would be more effective than single‐agent treatment. To compare the inhibition of cell proliferation in single agent versus combination treatment, we performed an 11‐point dose escalation experiment using osimertinib or DDC‐01‐163 alone or in combination with two constant doses of DDC‐01‐163 and osimertinib, respectively (Figure A).…”

Compound 15c, a Novel Dual Inhibitor of EGFRL858R/T790M and FGFR1, Efficiently Overcomes Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Resistance of Non-Small-Cell Lung Cancers

“…By targeting the genetic differences of cancer cells, several molecule-targeting drugs, such as Afatinib and Gefitinib, had been approved by U.S. FDA and shown their promising therapeutic activity against various cancers (Cataldo et al, 2011;Hirsch and Bunn, 2012). However, the therapeutic strategies of "one drug-hits-one target-treats-one disease" still face significant challenges as the drug resistance (To et al, 2019;Wojtaszek et al, 2019). Recent studies suggested that targeting the multiple targets might be a practicable approach to ameliorate the therapeutic activity and selectivity, meanwhile preventing the drug resistance (To et al, 2019).…”

“…However, the therapeutic strategies of "one drug-hits-one target-treats-one disease" still face significant challenges as the drug resistance (To et al, 2019;Wojtaszek et al, 2019). Recent studies suggested that targeting the multiple targets might be a practicable approach to ameliorate the therapeutic activity and selectivity, meanwhile preventing the drug resistance (To et al, 2019).…”