Increasing TET expression and 5-hydroxymethylcytosine formation by a carbocyclic 5-aza-2’-deoxy-cytidine antimetabolite [methylation]

Because the presence of 5mdC in the promoter region of a given gene silences its expression, this oxidation goes in hand with the reactivation of such silenced genes. In different highly aggressive cancers such as acute myeloid leukemia (AML) and glioblastoma, loss of TET enzyme function and therefore reduced 5hmdC levels pave the way for tumor development.

Impairment of TET activity can occur through metabolic inhibition, through loss-of-function mutations in TET genes themselves, and finally through suppression of TET-expression via epigenetic silencing. Reactivation of TET enzyme expression represents a major aim of epigenetic cancer therapy. Here we show that the carbocyclic antimetabolite 5-aza-2’deoxycytidine (cAzadC), which is supposed to suppress the methylation of DNA during replication, leads to a substantial increase of TET2 expression and strongly increasing 5hmdC levels.