A Temporal PROTAC Cocktail‐Mediated Sequential Degradation of AURKA Abrogates Acute Myeloid Leukemia Stem Cells

Abstract

AURKA is a potential kinase target in various malignancies. The kinase‐independent oncogenic functions partially disclose the inadequate efficacy of the kinase inhibitor in a Phase III clinical trial. Simultaneously targeting the catalytic and noncatalytic functions of AURKA may be a feasible approach. Here, a set of AURKA proteolysis targeting chimeras (PROTACs) are developed. The CRBN‐based dAurA383 preferentially degrades the highly abundant mitotic AURKA, while cIAP‐based dAurA450 degrades the lowly abundant interphase AURKA in acute myeloid leukemia (AML) cells. The proteomic and transcriptomic analyses indicate that dAurA383 triggers the “mitotic cell cycle” and “stem cell” processes, while dAurA450 inhibits the “MYC/E2F targets” and “stem cell” processes. dAurA383 and dAurA450 are combined as a PROTAC cocktail. The cocktail effectively degrades AURKA, relieves the hook effect, and synergistically inhibits AML stem cells. Furthermore, the PROTAC cocktail induces AML regression in a xenograft mouse model and primary patient blasts. These findings establish the PROTAC cocktail as a promising spatial‐temporal drug administration strategy to sequentially eliminate the multifaceted functions of oncoproteins, relieve the hook effect, and prevent cancer stem cell‐mediated drug resistance.

Discovery of a Novel Orally Bioavailable FLT3-PROTAC Degrader for Efficient Treatment of Acute Myeloid Leukemia and Overcoming Resistance of FLT3 Inhibitors

“…However, only CRBN and VHL are the two most commonly employed ligases. Notably, several orally bioavailable CRBN-recruited bifunctional degraders have entered clinical trials. − Therefore, several CRBN- and VHL-recruited degraders were first synthesized by converting the pyrrolidine group of PXA13 to piperazine to attach the linker and E3 ligase ligand (Figure ). In the first round of design, it was found that CRBN-recruited degraders showed stronger antiproliferative activities against FLT3-ITD-positive AML cells MV4-11 and MOLM-13 (Table ).…”

From classic medicinal chemistry to state‐of‐the‐art interdisciplinary medicine: Recent advances in proteolysis‐targeting chimeras technology

“…Therefore, it is of great significance to develop more E3 ligands and explore the possibility of PROTAC‐induced POI degradation by other E3 ligases in the future. At the same time, it is also beneficial to develop tissue‐specific PROTACs according to the different tissue expression of E3 ligases and to develop cell cycle‐specific PROTACs or concomitant drugs according to the dynamic expression process of E3 ligases in the cell cycle 162 . In addition, in order to better deal with the drug resistance caused by the bypass signal pathway mechanism, it is also worth exploring suitable bypass targets, designing a reasonable combination strategy, or developing dual‐target PROTAC degradants.…”

Identification of Suitable Target/E3 Ligase Pairs for PROTAC Development using a Rapamycin-induced Proximity Assay (RiPA)

“…This is relevant because several studies with PROTACs indicate efficient degradation of WDR5 by VHL but not by CRBN 29,31 . In contrast, CRBN-based PROTACs have been shown to efficiently degrade the mitotic kinase Aurora A 10,11,[33][34][35] . We therefore tested whether VHL and CRBN are able to degrade Aurora A in the RiPA system.…”