Wu-5, a novel USP10 inhibitor, enhances crenolanib-induced FLT3-ITD-positive AML cell death via inhibiting FLT3 and AMPK pathways

The kinase FLT3 internal tandem duplication (FLT3-ITD) is related to poor clinical outcomes of acute myeloid leukemia (AML). FLT3 inhibitors have provided novel strategies for the treatment of FLT3-ITD-positive AML. But they are limited by rapid development of acquired resistance and refractory in monotherapy. Recent evidence shows that inducing the degradation of FLT3-mutated protein is an attractive strategy for the treatment of FLT3-ITD-positive AML, especially those with FLT3 inhibitor resistance. In this study we identified Wu-5 as a novel USP10 inhibitor inducing the degradation of FLT3-mutated protein. We showed that Wu-5 selectively inhibited the viability of FLT3 inhibitor-sensitive (MV4-11, Molm13) and -resistant (MV4-11R) FLT3-ITD-positive AML cells with IC50 of 3.794, 5.056, and 8.386 mu M, respectively. Wu-5 (1-10 mu M) dose-dependently induced apoptosis of MV4-11, Molm13, and MV4-11R cells through the proteasome-mediated degradation of FLT3-ITD. We further demonstrated that Wu-5 directly interacted with and inactivated USP10, the deubiquitinase for FLT3-ITD in vitro (IC50 value = 8.3 mu M) and in FLT3- ITD-positive AML cells. Overexpression of USP10 abrogated Wu-5-induced FLT3-ITD degradation and cell death. Also, the combined treatment of Wu-5 and crenolanib produced synergistic cell death in FLT3-ITD-positive cells via the reduction of both FLT3 and AMPK alpha proteins. In support of this, AMPK alpha inhibitor compound C synergistically enhanced the anti-leukemia effect of crenolanib, while AMPK alpha activator metformin inhibited the anti-leukemia effect of crenolanib. In summary, we demonstrate that Wu-5, a novel USP10 inhibitor, can overcome FLT3 inhibitor resistance and synergistically enhance the anti-AML effect of crenolanib through targeting FLT3 and AMPK alpha pathway.

Automated summary

The novel USP10 inhibitor Wu-5 induces degradation of FLT3-ITD protein, selectively inhibits FLT3-ITD-positive AML cells, especially those resistant to FLT3 inhibitors. Combined treatment of Wu-5 and crenolanib synergistically enhances anti-AML effect by targeting FLT3 and AMPK alpha pathway.