MDL-800 is a selective allosteric activator of SIRT6, a member of the SIRT deacetylase family that is responsible for deacetylation of histones H3K9Ac and H3K56ac and has tumor suppressor activity. MDL-800 increased the deacetylase activity of SIRT6 by up to 22-fold resulting in a decrease in H3K9Ac and H3K56Ac in hepatocellular carcinoma (HCC) cells, causing cell cycle arrest and inhibiting their proliferation. It also suppressed the growth of xenografts of the hepatocellular carcinoma cell line BEL7405.