Antioxidants produced by the body delay the aging of cells. But when the cells in question are cancerous, these molecules would be far from beneficial to our health. According to two studies published a week apart in the journals Science Translational Medicine and Nature, taking antioxidants could even promote the spread of metastases if a melanoma is already present.
The first works, published on October 7, 2015, concern the injection of acetylcysteine (precursor of glutathionea cell protector oxidative stress) in the organism of mice grafted with melanomas humans. According to the data presented, these cancers grow faster – with a proliferation of metastases – in the group of animals treated with these antioxidants than in the control group.
A week later, the magazine Nature publishes similar results, obtained by a North American team. The experiments, also conducted in mice, show that melanoma metastases grow faster in treated animals supplemented with antioxidants.
The risk identified in mice in these two studies has not yet been confirmed in humans.
The analyzes carried out by these researchers suggest that metastasized melanoma cells experience very high levels of oxidative stress. “This leads to the death of most of the metastatic cells”, explains in a press release, Sean Morrison, co-author of the second study. Antioxidants would limit the destruction of metastases, and would promote de facto their proliferation. “Cancer cells [profiteraient] more antioxidants than normal cells.” His team advances the hypothesis that promoting the oxidative stress cancer cells, via targeted treatments with pro-oxidants, could slow down the proliferation of metastases.
- Antioxidants can increase melanoma metastasis in mice. MO Bergo et al. Science Translational Medicine, 2015 Oct 7. doi: 10.1126/scitranslmed.aad3740
- Oxidative stress inhibits distant metastasis by human melanoma cells. E. Piskounova et al. Nature, October 14, 2015. doi:10.1038/nature15726