L002

L002 (NSC764414) is an inhibitor of acetyltransferase p300, a lysine acetyltransferase that catalyzes acetyl group attachment to lysine residues of a variety of proteins including histones and p53, and acts as a critical coactivator of several oncogenic transcription factors involved in cancer cell survival and proliferation including STAT3, NF-kB, and hypoxia-inducible factor-1α (HIF-1α). L002 (NSC764414) was discovered from compounds assayed for cytotoxicity to the triple-negative breast cancer (TNBC) cell line MDA-MB-231 but not to the human mammary epithelial cells, then further screened for inhibition of p300. L002 has an in vitro IC₅₀ of 1.98 μM for p300 with lesser inhibition of the GNAT (GCN5-related N-acetyltransferase) family, and no inhibition against the MYST family of histone acetyltransferases (HATs), histone deacetylases (HDACs), or histone methyltransferases (HMTs). L002 potently suppressed tumor growth and histone acetylation of MDA-MB-468 xenografts and leukemia and lymphoma cell lines.