Background:

SGI-1027 is an inhibitor of DNMT with IC50 values of 12.5μM, 8μM and 7.5μM, respectively for DNMT1, DNMT3A and DNMT3B [1].

SGI-1027 shows inhibition with mammalian DNMTs and bacterial M. SssI in vitro. Both the endogenous and recombinant DNMTs can be inhibited by SGI-1027. The mechanism of this inhibition is that SGI-1027 competes with Ado-Met but not the substrate DNA within the cofactor binding site of the enzyme. SGI-1027 inhibits DNA methylation through directly inhibiting DNMTs [1].

In cancer cells, many TSGs are silenced due to hypermethylation of CpG islands in their promoters. SGI-1027 can demethylates these CpG islands and reactivate the silenced TSGs. In RKO cells, prolonged treatment of SGI-1027 induces reexpression of P16 and TIMP3 genes. Moreover, SGI-1027 is found to cause selective degradation of DNMT1 via proteasomal pathway [1].

参考文献:
[1] Datta J, Ghoshal K, Denny WA, Gamage SA, Brooke DG, Phiasivongsa P, Redkar S, Jacob ST. A new class of quinoline-based DNA hypomethylating agents reactivates tumor suppressor genes by blocking DNA methyltransferase 1 activity and inducing its degradation. Cancer Res. 2009 May 15;69(10):4277-85.