Discovery of Isoform-Selective Akt3 Degraders Overcoming Osimertinib-Induced Resistance in Non-Small Cell Lung Cancer Cells

EGFR inhibitor therapies have brought significant benefit
to NSCLC
patients. However, all patients gradually progress to acquired resistance via diverse mechanisms. Akt3 overexpression but not Akt1/2
is one of the found molecular events that mediate osimertinib (1) resistance in NSCLC patients. Here, we report 12l as the first bona fide isoform-selective Akt3 degrader which potently
induced proteasomal degradation of the target both in vitro and in vivo, whereas its effects on Akt1/2 were
minimal. Using 12l as a tool, non-canonical function
of Akt3 was validated to contribute greatly to survival of 1-resistant H1975OR NSCLC cells. Degrader 12l potently
suppressed the growth of H1975OR as well as several NSCLC cell lines
with low nanomolar IC50 values and demonstrated promising in vivo antitumor efficacy in nude mice bearing H1975OR
or PC9 NSCLC xenograft models. Selective degradation of Akt3 may be
considered as a novel strategy for human cancer therapy.