HDAC8-IN-14 is a curcumin derivative serving as a selective HDAC8 inhibitor with a Ki of 9 nM. It induces reactive oxygen species (ROS) production, disrupts mitochondrial membrane potential, and promotes apoptosis. Furthermore, HDAC8-IN-14 significantly triggers cell accumulation in the sub-G0/G1 phase, indicative of apoptosis or necroptosis. It upregulates cytochrome c, cleaved caspase-3, and pro-apoptotic protein Bak expression, while maintaining anti-apoptotic protein Bcl-2 levels unchanged, making it a valuable compound for leukemia research.

HDAC8:9 nM (Ki)

HDAC8-IN-14 (Compound 5e) demonstrates a low IC50 value of 90 nM in MOLT-4 cells when exposed at concentrations ranging from 0.1 to 100 μM for 48 hours. In EL-4 cells, the IC50 value is 1.98 μM, 1.17 μM in YAC-1 cells, and 18.94 μM in L1210 cells. In contrast, the compound shows a significantly higher IC50 value of 39.20 μM in the non-cancerous HEK-293 cell line, indicating selectivity and safety towards non-cancer cells. At 100 nM for 30 minutes, HDAC8-IN-14 induces notable ROS production in MOLT-4 cells, detected using the fluorescent dye H2DCFDA. After 48 hours, the compound causes mitochondrial depolarization, reflected by changes in JC-1 fluorescence intensity; it triggers approximately 10% apoptosis and 30% necrosis and leads to cell cycle arrest, with a 20% increase in sub-G0 apoptotic cells, reduced proportions of cells in G0/G1 and G2/M phases, and a slight increase in S phase cells. At concentrations of 50-100 nM, HDAC8-IN-14 significantly upregulates cytochrome c, cleaved caspase-3, and pro-apoptotic protein Bak expressions, while maintaining constant levels of the anti-apoptotic protein Bcl-2. This suggests activation of an intrinsic apoptosis pathway in MOLT-4 cells via a Bcl-2-independent mechanism.

HDAC8-IN-14, administered intraperitoneally at a dose of 50 mg/kg once daily for 30 days, effectively inhibits tumor growth in a DLA mouse model without exhibiting significant systemic toxicity.