SGI-503

SGI-503 is a potent, non-nucleoside small molecule inhibitor of DNA methyltransferase 1 (DNMT1). Developed by Astex Pharmaceuticals, it functions by binding to the catalytic site of DNMT1, thereby preventing the maintenance of DNA methylation patterns during cell division. Unlike traditional nucleoside analogs such as decitabine or azacitidine, SGI-503 does not require incorporation into the DNA backbone to exert its inhibitory effect, which potentially reduces DNA damage-related toxicity and improves the safety profile. Preclinical studies have demonstrated its efficacy in inducing the re-expression of silenced tumor suppressor genes and inhibiting the growth of various solid tumors and hematological malignancies. It is often utilized in research to study epigenetic regulation and as a lead candidate for developing next-generation epigenetic therapies.