Anacardic acid (16611-84-0) is a natural product found in cashew nut oil.  It is an inhibitor of the histone acetyltransferases p300 and PCAF (IC₅₀’s = 8.5 and 5.0 µM respectively).¹  Anacardic acid sensitizes cancer cells to ionizing radiation² and suppresses proteins involved in invasion and angiogenesis (Src/FAK/Rho GTPases³ and MMP’s 2 (IC₅₀ = 11.11 µM)⁴ and 9).  It inhibits both inducible and constitutive NF-κB activation.⁵

References/Citations:

1) Balasubramanyam et al. (2003), Small molecule modulators of histone acetyltransferase p300; J. Biol. Chem. 278 19134
2) Sun et al. (2006), Inhibition of histone acetyltransferase activity by anacardic acid sensitizes tumor cells to ionizing radiation; FEBS Lett. 580 4353
3) Wu et al. (2011), Anacardic acid (6-Pentadecylsalicylic acid) Inhibits Tumor Angiogenesis by Targeting Src/FAK/Rho GTPases Signaling Pathway; J. Pharmacol. Exp. Ther. 339 403
4) Omanakuttan et al. (2012), Anacardic acid Inhibits the Catalytic Activity of Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9; Mol. Pharmacol. 82 614
5) Sung et al. (2008), Anacardic acid (6-nonadecyl salicylic acid), an inhibitor of histone acetyltransferase, suppresses expression of nuclear factor-kB- regulated gene products involved in cell survival, proliferation, invasion, and inflammation through inhibition of the inhibitory subunit of nuclear factor-kBα kinase, leading to potentiation of apoptosis; Blood 111 4880