6-Thioguanine

After incorporation into DNA, it disrupts cytosine methylation by DNA methyltransferases in vitro and acts as a DNA demethylating agent in vivo.1 It reactivates epigenetically silenced genes in acute lymphoblastic leukemia cells by facilitating proteasome-mediated degradation of DNA methyltransferase (DNMT1) .2 Incorporates into DNA and induces double strand breaks which destabilize DNA structure resulting in cytotoxicity.3 Selectively kills BRCA2-defective tumors and overcomes PARP inhibitor resistance in a xenograft model.4 Anticancer and immunosuppressive activity.