Novel Allosteric Inhibitor-Derived AKT Proteolysis Targeting Chimeras (PROTACs) Enable Potent and Selective AKT Degradation in KRAS/BRAF Mutant Cells

Abstract

AKT is an important target for cancer therapeutics. Significant advancements have been made in developing ATP-competitive and allosteric AKT inhibitors. Recently, several AKT proteolysis targeting chimeras (PROTACs) derived from ATP-competitive AKT inhibitors have been reported, including MS21. While MS21 potently degraded AKT and inhibited the growth in tumor cells harboring PI3K/PTEN pathway mutation, it was largely ineffective in degrading AKT in KRAS/BRAF mutated cells as a single agent. To overcome the AKT degradation resistance in KRAS/BRAF mutated cells, we developed novel AKT PROTACs derived from an AKT allosteric inhibitor, including degrader <b>62</b> (MS15). <b>62</b> displayed potent and selective AKT degradation activity and potent antiproliferative activity in KRAS/BRAF mutated cancer cells, in addition to PI3K/PTEN mutated cancer cells. Furthermore, <b>62</b> was bioavailable in mice through intraperitoneal administration. Overall, <b>62</b> is a valuable chemical tool to degrade AKT in cells harboring KRAS/BRAF mutation and expands the tool box for pharmacologically modulating AKT.