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Heterobifunctional degraders, known as proteolysis targeting chimeras (PROTACs), theoretically possess a catalytic mode-of-action, yet few studies have either confirmed or exploited this potential advantage of event-driven pharmacology. Degraders of oncogenic EML4-ALK fusions were developed by conjugating ALK inhibitors to cereblon ligands. Simultaneous optimization of pharmacology and compound properties using ternary complex modeling and physicochemical considerations yielded multiple catalytic degraders that were more resilient to clinically relevant ATP-binding site mutations than kinase inhibitor drugs. Our strategy culminated in the design of the orally bioavailable derivative CPD-1224 that avoided hemolysis (a feature of detergent-like PROTACs), degraded the otherwise recalcitrant mutant L1196M/G1202R in vivo, and commensurately slowed tumor growth, while the third generation ALK inhibitor drug lorlatinib had no effect. These results validate our original therapeutic hypothesis by exemplifying opportunities for catalytic degraders to proactively address binding site resistant mutations in cancer.

In-frame insertions in exon 20 of HER2 are the most common HER2 mutations in patients with non-small cell lung cancer (NSCLC), a disease in which approved EGFR/HER2 tyrosine kinase inhibitors (TKI) display poor efficiency and undesirable side effects due to their strong inhibition of wild-type (WT) EGFR. Here, we report a HER2-selective covalent TKI, JBJ-08-178-01, that targets multiple HER2 activating mutations, including exon 20 insertions as well as amplification. JBJ-08-178-01 displayed strong selectivity toward HER2 mutants over WT EGFR compared with other EGFR/HER2 TKIs. Determination of the crystal structure of HER2 in complex with JBJ-08-178-01 suggests that an interaction between the inhibitor and Ser783 may be responsible for HER2 selectivity. The compound showed strong antitumoral activity in HER2-mutant or amplified cancers in vitro and in vivo. Treatment with JBJ-08-178-01 also led to a reduction in total HER2 by promoting proteasomal degradation of the receptor. Taken together, the dual activity of JBJ-08-178-01 as a selective inhibitor and destabilizer of HER2 represents a combination that may lead to better efficacy and tolerance in patients with NSCLC harboring HER2 genetic alterations or amplification., Significance: This study describes unique mechanisms of action of a new mutant-selective HER2 kinase inhibitor that reduces both kinase activity and protein levels of HER2 in lung cancer., (©2022 American Association for Cancer Research.)

Despite advances in precision medicine approaches over the past decade, the majority of nonsmall cell lung cancers (NSCLCs) are refractory to treatment with targeted small molecule inhibitors. Previous work has identified mutations in the Discoidin Domain Receptor 2 (DDR2) kinase as potential therapeutic targets in NSCLCs. While DDR2 is potently targeted by several multitargeted kinase inhibitors, most notably dasatinib, toxicity has limited the clinical application of anti-DDR2 therapy. Here, we have characterized compound 1 and other tool compounds demonstrating selectivity for DDR2 and show that while these compounds inhibit DDR2 in lung cancer model systems, they display limited antiproliferative activity in DDR2 mutated cell lines as compared to dual DDR2/SRC inhibitors. We show that DDR2 and SRC are binding partners, that SRC activity is tied to DDR2 activation, and that dual inhibition of both DDR2 and SRC leads to enhanced suppression of DDR2 mutated lung cancer cell lines. These results support the further evaluation of dual SRC/DDR2 targeting in NSCLC, and we report a tool compound, compound 5, which potently inhibits both SRC and DDR2 with a distinct selectivity profile as compared to dasatinib.

The treatment of patients with advanced non-small-cell lung cancer harboring chromosomal rearrangements of anaplastic lymphoma kinase (ALK) has been revolutionized by the development of crizotinib, a small-molecule inhibitor of ALK, ROS1, and MET. However, resistance to crizotinib inevitably develops through a variety of mechanisms, leading to relapse both systemically and in the central nervous system (CNS). This has motivated the development of "second-generation" ALK inhibitors, including alectinib and ceritinib, that overcome some of the mutations leading to resistance. However, most of the reported ALK inhibitors do not show inhibition of the G1202R mutant, which is one of the most common mutations. Herein, we report the development of a structural analogue of alectinib (JH-VIII-157-02) that is potent against the G1202R mutant as well as a variety of other frequently observed mutants. In addition, JH-VIII-157-02 is capable of penetrating the CNS of mice following oral dosing.