Loss of 'DNA tag' could be key to melanoma growth

In collaboration with the Press Association

Skin cells that have lost a common chemical tag from their DNA could be more likely to develop into melanoma cells - the most deadly type of skin cancer - according to US research.

Experts from the Brigham and Women's Hospital in Boston were able to halt the growth of melanoma in animal models by re-introducing the so-called 'epigenetic' tag into the cancer cells.

The research suggests that treatments that reverse the epigenetic defect could be developed.

The study found that a particular epigenetic tag in the DNA of normal skin cells and healthy mole cells called 5-hmC was missing in the DNA from melanoma cells.

The researchers, led by Dr Yujiang Geno Shi, were able to halt melanoma growth in animal models by introducing enzymes responsible for the formation of 5-hmC to melanoma cells that lacked the tag. Once this was done the cells stopped growing.

Dr Christine Lian, co-lead author from the Brigham and Women's Hospital, said: "It is difficult to repair the mutations in the actual DNA sequence that are believed to cause cancer.

"So having discovered that we can reverse tumour cell growth by potentially repairing a biochemical defect that exists - not within the sequence - but just outside of it on the DNA structure, provides a promising new melanoma treatment approach for the medical community to explore."

Dr Santiago Uribe-Lewis, an epigenetics expert based at the Cancer Research UK Cambridge Research Institute, said: “Evidence is mounting that many different types of tumour, including brain and bowel cancers, have depleted levels of  5-hmC. This latest study is very interesting, as it shows that it’s possible to replenish 5-hmC levels in melanoma cells, and that this can help to slow the growth of tumours in animal models.

“The challenge now is to translate this early-stage lab work into an effective treatment for people – this is no easy task, but this work is a step towards that goal.”

Over the last thirty years, rates of melanoma in Britain have risen faster than any of the current top ten cancers. If the work is developed further, the findings could have significant repercussions for treatment and prevention of the disease, which claims more than 2,000 lives in the UK every year.

The study is published in the journal Cell.

Copyright Press Association 2012

References

  • Lian, C. et al. & (2012). Loss of 5-Hydroxymethylcytosine Is an Epigenetic Hallmark of Melanoma, Cell, 150 (6) 1146. DOI: 10.1016/j.cell.2012.07.033