3-deazaneplanocin

The lysine methyltransferase EZH2 (KMT6), part of the polycomb repressive complex 2, catalyzes trimethylation of lysine 27 on histone H3 and is involved in proliferation and aggressive cell growth associated with neoplastic cells. 3-Deazaneplanocin A is a cyclopentenyl analog of 3-deazaadenosine, originally synthesized as an inhibitor of S-adenosyl-L-homocysteine hydrolase. It has been shown to deplete EZH2 levels and to inhibit trimethylation of lysine 27 on histone H3 in cultured human acute myeloid leukemia (AML) HL-60 and OCI-AML3 cells and in primary AML cells in a dose-dependent manner (0.2-1 μM). 3-Deazaneplanocin A treatment of cultured human AML cells induces increased expression of the cell-cycle regulators p21, p27, and FBXO32, leading to cell cycle arrest and apoptosis. When used in combination with the pan-histone deacetylase inhibitor panobinostat (10 mg/kg), 3-deazaneplanocin A’s (1 mg/kg) antileukemic effects are synergistically enhanced in mice implanted with AML cells.