belinostat + bortezomib

Belinostat + bortezomib is an experimental combination regimen of two antineoplastic small molecule agents: **belinostat**, a pan-histone deacetylase (HDAC) inhibitor, and **bortezomib**, a proteasome inhibitor. This combination has shown synergistic activity in preclinical models and early-phase clinical trials involving various cancers, including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and renal cell carcinoma. The regimen induces apoptosis through multiple mechanisms: - Belinostat inhibits HDAC enzymes leading to hyperacetylation of histones and non-histone proteins (e.g., α-tubulin), alterations in chromatin structure, and transcriptional changes that favor cell death. - Bortezomib inhibits the 26S proteasome, leading to accumulation of ubiquitinated proteins, induction of ER stress, and interference with survival pathways like NF-κB. - The combination disrupts both canonical and non-canonical NF-κB signaling, downregulates anti-apoptotic proteins such as XIAP and Bcl-xL, upregulates pro-apoptotic factors like Bim, and induces endoplasmic reticulum stress. - In preclinical leukemia models and a phase 1 clinical trial, this combination resulted in a marked increase in apoptosis and cell death in tumor cells, while sparing normal hematopoietic progenitor cells[1][2][3].