Design, Synthesis, and Evaluation of ( R)-8-((Tetrahydrofuran-2-yl)methyl)pyrido[2,3- d]pyrimidin-7-ones as Novel Selective ACK1 Inhibitors to Combat Acquired Resistance to the Third-Generation EGFR Inhibitor

Activated Cdc42-associated kinase 1 (Ack1) alterations have been considered to mediate bypass acquired resistance to the third-generation EGFR inhibitors (ASK120067 and osimertinib) in NSCLC. Despite many efforts to develop Ack1 small molecule inhibitors, no selective inhibitors have entered clinical trials. We used structure-based drug design to obtain a series of (R)-8-((tetrahydrofuran-2-yl)methyl)pyrido [2,3-d]pyrimidin-7-ones as novel selective Ack1 inhibitors. One of the representative compounds, 10zi, potently inhibited Ack1 kinase with an IC₅₀ of 2.1 nM, while sparing Src kinase (IC₅₀ = 218.7 nM). Further, 10zi displayed good kinome selectivity in a profiling of 468 kinases. In the ASK120067-resistant lung Cancer cell line (67R), 10zi dose-dependently inhibited the phosphorylation of Ack1 and downstream Akt pathway and showed a strong synergistic anti-tumor effect in combination with ASK120067 in vitro. Additionally, 10zi also exhibited reasonable PK profiles with an oral bioavailability of 19.8% at the dose of 10 mg/kg, which provided a promising lead for further development of new Anticancer drugs.