Pharmacological methyl group donors block skeletal metastasis in vitro and in vivo.

Background And Purpose: DNA hypomethylation was previously implicated in metastasis. In the present study, we examined whether methyl supplementation with the universal methyl donor S-adenosylmethionine (SAM) inhibits prostate cancer associated skeletal metastasis.

Experimental Approach: Highly invasive human prostate cancer cells PC-3 and DU-145 were treated with vehicle alone, S-adenosylhomocysteine (SAH) or SAM and their effects on tumour cell proliferation, invasion, migration and colony formation were monitored.

Synergistic effects of combined DNA methyltransferase inhibition and MBD2 depletion on breast cancer cells; MBD2 depletion blocks 5-aza-2'-deoxycytidine-triggered invasiveness.

5-Aza-2'-deoxycytidine (5-azaCdR) not only inhibits growth of non-invasive breast cancer cells but also increases their invasiveness through induction of pro-metastatic genes. Methylated DNA binding protein 2 (MBD2) is involved in silencing methylated tumor suppressor genes as well as activation of pro-metastatic genes. In this study, we show that a combination of MBD2 depletion and DNA methyltransferases (DNMT) inhibition in breast cancer cells results in a combined effect in vitro and in vivo, enhancing tumor growth arrest on one hand, while inhibiting invasiveness triggered by 5-azaCdR on the other hand.

Synergistic anti-breast cancer effect of a combined treatment with the methyl donor S-adenosyl methionine and the DNA methylation inhibitor 5-aza-2'-deoxycytidine.

DNA-demethylating agents activate tumor suppressor genes that are silenced by DNA methylation in cancer and are therefore emerging as a novel approach to cancer therapy. 5-azacytidine (VIDAZA), the first representative of this class of drugs was approved for treatment of myelodysplastic syndromes and is currently being tested on other cancers including solid tumors. However, 5-azacytidine or its deoxy-analog, 5-aza-2'-deoxycytidine (5-azaCdR) could also induce methylated prometastatic genes by DNA demethylation and induce cancer cell invasiveness.

Role of epigenetics in cancer initiation and progression.

The epigenome which comprises DNA methylation, histone modifications, chromatin structures and non-coding RNAs controls gene expression patterns. In cancer cells, there are aberrant changes in the epigenome. The question in cancer epigenetics is that whether these changes are the cause of cell transformation, or rather the consequence of it.

Effects of specific DNMT gene depletion on cancer cell transformation and breast cancer cell invasion; toward selective DNMT inhibitors.

A hallmark of cancer is aberrant DNA methylation, consisting of global hypomethylation and regional hypermethylation of tumor suppressor genes. DNA methyltransferase inhibitors have been recognized as promising candidate anticancer drugs. Drug development has focused on DNA methylation inhibitors with the goal of activating tumor suppressor genes silenced by DNA methylation.