UNC0646 is a novel G9a inhibitor with excellent potency in a variety of cell lines and excellent separation of functional potency versus cell toxicity. UNC0646 has high in vitro potency versus G9a and improved lipophilicity, are highly potent (IC50 < 0.06 μM) in reducing H3K9me2 levels in MDA-MB-231 cells and has low cell toxicity.^[1]

Due to its water insolubility, the in vivo efficacy of UNC0646 is not satisfactory. Nanodiamonds (NDs) are utilized as a drug delivery platform to improve in vivo delivery of this small-molecule inhibitor. ND-UNC0646 complexes can be rapidly synthesized by physical adsorption, meanwhile possessing favorable drug delivery properties and is able to improve the dispersibility of UNC0646 in water, therefore making it amenable for intravenous administration. The release profile of UNC0646 from NDUNC0646 is demonstrated to be pH-responsive. Moreover, ND-UNC0646 maintains the biological functionality of UNC0646, with higher efficacy in reducing H3K9 methylation as well as enhanced invasion suppressive effects. Most importantly, increased in vivo efficacy is demonstrated using an orthotopic Hepatocellular carcinoma (HCC) mouse model, which paves the way of translating this small-molecule inhibitor toward HCC treatment.^[2]