Importantly, however, after only 5 days EWS-FLI1 reactivated expression of 81 hNCSC-associated genes and inhibited expression of 126 hNC-MSC-associated genes (Table S3A).
Although inhibiting DNA methylation and histone deacetylation usually reactivates expression of silenced alleles [38], [39], such renewed expression is often unstable and quickly re-silences at a high frequency, possibly as a consequence of retention of some repressive histone modifications [29], [30].
These demethylating agents have been shown to reactivate expression of numerous methylation-silenced genes.
Mechanical loading clearly reactivated expression of the aggrecan and type II collagen genes at loading of 60 min/day compared to the other durations of loading.
Common to all Burkitt lymphomas, endemic or sporadic, are distinctive chromosomal translocations that reactivate expression of the c-myc protooncogene and comprise the primary oncogenic mechanism.
To extend the knowledge of factors involved in RdDM and related RdTGS, we performed a screen for ethyl methanesulfonate (EMS -induced nrd mutants that rEMS -inducedpressionrdf a silenced reporter gene, according to the strategy outlined by Page and Grossniklaus.
AZA reactivated expression of Leprel1 and Leprel2 mRNA in DG75 and Ramos, consistent with methylation-dependent silencing and western blotting confirmed increased Leprel2 in Ramos cells treated with AZA.
This loss of expression was found to be due to aberrant nuclear factor-kappa B (NF-κB) binding to its promoter, and, critically, both DNMT inhibitors and HDAC inhibitors (HDACis) could reactivate expression of miR-146a and improve LPS-induced inflammatory responses in macrophages isolated from aged mice [ 47].
Lastly, we note that the identification of gene silencing in cancer in association with CpG island methylation has led to the discovery of 5-azacytidine as a drug able to reactivate expression of such genes and to the use of 5-azacytidine for cancer treatment.
Genistein-mediated promoter hypomethylation and hyperacetylation reactivate expression of tumor suppressor genes in human prostate cancer cells and are followed by cell cycle arrest and cellular apoptosis induced by cyclin and caspase pathways, respectively (Majid et al. 2008; Kikuno et al. 2008).
