A study published in the journal Nature has found that circulating cancer cells are under oxidative stress and therefore antioxidant supplementation in mice can promote their survival and the resultant spread of cancer.
In order for cancer to spread, the tumor cells must detach from the primary tumor and migrate through the blood to a new site. This process is not very efficient, and while circulating tumor cells are commonly found in the blood, the successful metastasis (survival and proliferation) of these cells to a different site of the body is more difficult.
A group of researchers from the University of Texas Southwestern Medical Center, Texas, USA, conducted a series of studies in mice to characterise metastasizing melanoma cells. They found that the melanoma cells present in the blood or visceral organs were under oxidative stress, containing a greater amount of reactive oxygen species, compared to the cells present within the tumors.
The researchers then conducted an experiment in which they transplanted melanoma cells into mice, in addition to treating the mice with antioxidant injections. They found that the mice treated with antioxidant injections had a higher frequency of circulating melanoma cells and metastasis compared with mice that were not treated with antioxidant injections.
The researchers suggest that the antioxidants promote tumor progression by promoting metastasis in this experimental model. If these results are confirmed in human studies this could have important implications for those diagnosed with cancer who are taking antioxidant supplements. Further research is necessary to determine whether these results extend to other cancer types.
Piskounova E, Agathocleous M, Murphy MM, Hu Z, Huddlestun SE, Zhao Z, Leitch AM, Johnson TM, DeBerardinis RJ, Morrison SJ “Oxidative stress inhibits distant metastasis by human melanoma cells.” Nature. 2015 Oct 14. doi: 10.1038/nature15726. [Epub ahead of print]
Written by Deborah Tallarigo, PhD