Antioxidants Responsible for Cancer Metastasis

Study suggests increasing oxidative stress through with pro-oxidants may prevent metastasis.

Researchers at the Children’s Research Institute at UT Southwestern (CRI) recently discovered that cancer cells benefit more from antioxidants than normal cells, suggesting danger in the use of dietary antioxidants by patients with cancer.

For the study, the researchers transplanted specialized mice with melanoma cells from human patients. Previous research showed that the metastasis of human melanoma cells in mice is a clear indicator of metastasis in patients.

Metastasis is the process by which cancer cells spread from their primary site to other parts of the body, leading to the death of most cancer patients. The CRI team found that when antioxidants were given to the mice, the rate of metastasis increased more quickly than in mice that did not receive antioxidants.

Scientists have long known of the dangers posed to cancer cells once it exits the primary site. The spread of cancer cells from one part of the body to another involves the death of the vast majority of cancer cells.

“We discovered that metastasizing melanoma cells experience very high levels of oxidative stress which leads to the death of most metastasizing cells,” said Dr. Sean Morrison, CRI director and Mary McDermott Cook chair in Pediatric Genetics at UT Southwestern Medical Center. “Administration of antioxidants to the mice allowed more of the metastasizing melanoma cells to survive, increasing metastatic disease burden.”

“The idea that antioxidants are good for you has been so strong that there have been clinical trials done in which cancer patients were administered antioxidants,” Dr. Morrison added. “Some of those trials had to be stopped because the patients getting the antioxidants were dying faster. Our data suggest the reason for this: cancer cells benefit more from antioxidants than normal cells do.”

Healthy individuals without cancer may benefit from antioxidants that can help decrease the damage from highly reactive oxidative molecules generated by normal metabolism.

The study’s results have not yet been confirmed in human models; still, they raise the possibility that cancer should be treated with pro-oxidants and that cancer patients should not supplement their diet with large doses of antioxidants.

“This finding also opens up the possibility that when treating cancer, we should test whether increasing oxidative stress through the use of pro-oxidants would prevent metastasis,” Dr. Morrison said. “One potential approach is to target the folate pathway that melanoma cells use to survive oxidative stress, which would increase the level of oxidative stress in the cancer cells.”