Design, Synthesis, and Biological Evaluation of Novel EGFR PROTACs Targeting Del19/T790M/C797S Mutation

Abstract

The tertiary epidermal growth factor receptor (EGFR) C797S mutation predominates in the acquired mutational resistance in cancer patients to third-generation EGFR inhibitors. Small-molecule inhibitors targeting the EGFR C797S mutation have been developed with good efficiency. However, these compounds may still induce new EGFR mutations to evade the inhibition pathway. One EGFR protein degrader based on an allosteric inhibitor has shown some benefits of degrading the EGFR L858R/T790M/C797S triple mutant. However, the degrader of the other important triple EGFR mutation Del19/T790M/C797S has not been reported. Here we present the design and synthesis of a series of EGFR proteolysis-targeting chimeras (PROTACs) that can rapidly and potently induce EGFR degradation in Ba/F3 cells expressing the EGFRDel19/T790M/C797S mutant. One representative compound 6h time- and dose-dependently induced EGFR degradation with a DC50 of 8 nM. It also showed good antiproliferation activity (IC50 = 0.02 μM) against Ba/F3-EGFRDel19/T790M/C797S cells. 6h may serve as a lead compound to develop therapeutic agents for the treatment of resistant non-small cell lung cancer patients with EGFR C797S mutants.

Proteolysis Targeting Chimeras (PROTACs): A Perspective on Integral Membrane Protein Degradation

“…Another contribution to improve IMP-targeted degradation could come from understanding the mechanisms that lead to the actual degradation of the POI in more detail. Many reports have demonstrated the involvement of the proteasome in the degradation of IMPs, ,,,,, while others have shown that the endolysosomal system is required. ,, Others have instead suggested that TPD involves the cooperation of the autophagic-lysosomal system and the UPS together, , though this could be induced by the inhibition of the proteasome, which can switch from a proteasome-dependent pathway to a lysosomal-dependent protein degradation pathway. , …”

“…23,25,46 instead suggested that TPD involves the cooperation of the autophagic-lysosomal system and the UPS together, 37,42 though this could be induced by the inhibition of the proteasome, which can switch from a proteasome-dependent pathway to a lysosomal-dependent protein degradation pathway. 76,77 As targets, each membrane-associated protein presents unique properties, such as its endogenous turnover and trafficking kinetics, and its susceptibility to be internalized, which do not hinge on the technology applied. On the other hand, TPD strategies differ in the E3 employed, its endogenous levels, turnover, and stoichiometry with the target.…”

Exploring Degradation of Mutant and Wild-Type Epidermal Growth Factor Receptors Induced by Proteolysis-Targeting Chimeras

“…Compound 29 was obtained as a white solid (20 mg, yield 89%). 1 (37). Compound 37 was synthesized following the standard procedure for preparing compound 21 from intermediates 88 (11.5 mg, 0.02 mmol) and 90d (10.9 mg, 0.02 mmol, 1.0 equiv).…”

“…Notably, Gray’s group also developed an allosteric inhibitor-derived EGFR degrader, 12 (DDC-01-163), which potently degraded mutant EGFRs without affecting WT EGFRs and inhibited the proliferation of L858R/T790M mutant Ba/F3 cells and osimertinib-resistant Ba/F3 cells harboring L858R/T790M/C797S or L858R/T790M/L718Q triple mutations . Very recently, Xu’s group discovered another allosteric EGFR inhibitor-derived VHL-recruiting degrader, 13 (compound 6h ), which potently depleted EGFRs with Del19/T790M/C797S triple mutations in Ba/F3 cells . Interestingly, among these previously developed EGFR PROTAC degraders, only compound 4 , which was based on the EGFR and HER2 dual inhibitor lapatinib, was reported to induce WT EGFR degradation .…”

“…36 Very recently, Xu's group discovered another allosteric EGFR inhibitor-derived VHL-recruiting degrader, 13 (compound 6h), which potently depleted EGFRs with Del19/T790M/ C797S triple mutations in Ba/F3 cells. 37 Interestingly, among these previously developed EGFR PROTAC degraders, only compound 4, which was based on the EGFR and HER2 dual inhibitor lapatinib, was reported to induce WT EGFR degradation. 28 All other reported EGFR degraders had no effect on degrading WT EGFRs except compounds 5 and 9, which were not assessed for their effect on degrading WT EGFRs.…”