A-485 is a potent and selective catalytic p300/CBP inhibitor with IC50 values of 9.8 nM for p300 and 2.6 nM for CBP.

p300:9.8 nM, CBP:2.6 nM

METHODS: 124 tumor cells were treated with A-485 for 3-5 days and cell viability was measured by the CellTiter-Glo Luminescent Cell Viability Assay.
RESULTS: The broadest sensitivity was observed in hematologic tumors, where A-485 exhibited potent activity in most multiple myeloma (MM) cell lines, acute myeloid leukemia (AML) cell lines, and non-Hodgkin's lymphoma (NHL) cell lines. In contrast, several solid tumor lines, including melanoma, small cell lung cancer (SCLC), and triple-negative breast cancer (TNBC), showed significantly reduced sensitivity to A-485. [1]
METHODS: H1650 and H1650-ER cells were treated with A-485 (20 µM) overnight, followed by TRAIL (10-100 ng/mL) overnight, and apoptosis was detected by apoptotic kit.
RESULTS: The combination of A-485 and TRAIL significantly increased the total number of apoptotic cells in H1650 and H1650-ER cells compared to TRAIL alone.A-485 enhanced TRAIL-induced apoptosis. [2]

METHODS: To assay in vivo anti-tumor activity, A-485 (100 mg/kg) was administered intraperitoneally twice daily for 21 days to SCID mice bearing LuCaP-77 CR xenografts.
RESULTS: A-485 induced 54% tumor growth inhibition (TGI) after 21 days of administration. [1]