Identification of a novel PAK1/HDAC6 dual inhibitor ZMF-23 that triggers tubulin-stathmin regulated cell death in triple negative breast cancer

Triple-negative breast cancer (TNBC) is the most poorly treated subtype of breast cancer, and targeting the heterogeneity of TNBC has emerged as a fascinating therapeutic strategy. In this study, we propose for the first time that dual-targeting PAK1 and HDAC6 is a promising novel strategy for TNBC treatment due to their essential roles in the regulation of energy metabolism and epigenetic modification. We discovered a novel dual-targeting PAK1/HDAC6 inhibitor, 6 -(2-(cyclopropylamino) -6 -(2,4-dichlorophenyl) -7 -oxopyrido [2,3-d] pyrimidin -8 (7H)-yl) -N-hydroxyhexanamide (ZMF-23), which presented profound inhibitory activity against PAK1 and HDAC6 and robust antiproliferative potency in MDA-MB-231 cells. In addition, SPR and CETSA assay demonstrated the targeted binding of ZMF-23 with PAK1/HDAC6. Mechanically, ZMF-23 strongly inhibited the cellular PAK1 and HDAC6 activity, impeded PAK1 and HDAC6 regulated aerobic glycolysis and migration. By RNA-seq analysis, ZMF-23 was found to induce TNF-& alpha;-regulated necroptosis, which further enhanced apoptosis. Additionally, ZMF-23 triggered PAK1-tubulin/HDAC6-Stathmin regulated microtubule structure changes, which further induced the G2/M cycle arrest. Moreover, prominent anti-proliferative effect of ZMF-23 was confirmed in the TNBC xenograft zebrafish and mouse model via PAK1 and HDAC6 inhibition. Collectively, ZMF-23 is a novel dual PAK1/HDAC6 inhibitor with TNBC treatment potential.

Automated summary

This study proposes the dual targeting of PAK1 and HDAC6 as a promising therapeutic strategy for triple-negative breast cancer (TNBC). A novel dual-targeting PAK1/HDAC6 inhibitor, ZMF-23, showed significant inhibitory activity against PAK1 and HDAC6 and demonstrated robust antiproliferative potency in TNBC cells.