PI3K and HDAC (dual inhibition)

Class

Small-molecule dual PI3K/HDAC inhibitor

Pathway

Simultaneous inhibition of phosphoinositide 3-kinase (PI3K/AKT/mTOR) signaling and histone deacetylases (HDAC), disrupting both proliferative signaling and epigenetic regulation in myeloma cells

This mechanism combines inhibition of two distinct cancer-relevant pathways within a single small molecule: phosphoinositide 3-kinase (PI3K), a lipid kinase central to the PI3K/AKT/mTOR signaling cascade that drives cell growth and survival, and histone deacetylases (HDACs), enzymes that remove acetyl groups from histone and non-histone proteins to regulate gene expression and protein stability. In malignant plasma cells, as seen in multiple myeloma, both pathways are frequently co-opted to sustain proliferation and resist cell death. PI3K/AKT/mTOR signaling supports growth factor-driven survival, while HDAC activity helps cancer cells manage the heavy protein-folding burden associated with antibody production, partly through control of chaperone proteins. Inhibiting only one pathway often allows the other to compensate, contributing to therapeutic resistance. A dual inhibitor is designed to suppress both simultaneously with a single pharmacokinetic profile, potentially achieving more durable disease control than sequential or combination use of two separate agents. This approach broadly matters in hematologic malignancies where tumor cells display dependence on parallel survival circuits, and reflects a wider strategy in oncology of targeting convergent vulnerabilities rather than a single node.