Researchers at the Wilmot Cancer Institute at the University of Rochester have identified glutathione, a naturally occurring antioxidant, as a critical nutrient that fuels cancer cell growth, according to a study published online by Nature on March 18. The research team, led by Isaac Harris, PhD, along with co-corresponding author Fabio Hecht, PhD, and co-first author Marco Zocchi, PhD, found that cancer cells are "addicted" to glutathione and use it as an energy source.
The findings highlight a new direction for cancer research and treatment. While antioxidants like glutathione are often associated with health benefits, this study suggests they may also play a role in supporting tumor growth. Harris said most previous studies focused on how glutathione prevents or repairs cell damage rather than its ability to feed cancer cells.
"Cancer cells and normal cells potentially use different food sources," Harris said. "We discovered how cancer cells, specifically, break down this antioxidant and use it as fuel." He added: "Maybe we need to re-examine the pantry that cancer relies on and look at things that we never thought could actually be used as food for tumors. There are additional complex metabolites that others are looking at, so we're potentially opening a whole new interest into how cancer cells acquire nutrients and how to block that activity. It's a really exciting time."
The researchers analyzed breast tumor samples from Wilmot's Biobank and found high levels of stored glutathione inside tumors. Using preclinical models of breast cancer, they were able to slow tumor growth by blocking the ability of cancer cells to use glutathione. Preliminary research indicates this mechanism may apply to other types of tumors as well.
Harris cautioned against taking high-dose antioxidant supplements such as glutathione pills: "Eating a balanced diet with fruits and vegetables is important. It can control weight, reduce inflammation, and support a healthy immune system," he said. "But people should be cautious about taking supplements in general, particularly glutathione. Taking a pill that is unregulated by the FDA and has a high concentration of glutathione can present risks." He emphasized that consuming antioxidant-rich whole foods remains beneficial.
The team also identified an existing drug developed nearly ten years ago that could inhibit tumors' ability to utilize glutathione. University of Rochester chemist Tom Driver and professor Joshua Munger are working on improving this drug further while exploring proteins involved in feeding glutathione to tumors. Future plans include testing combinations of anti-cancer drugs alongside dietary changes.
"Even though glutathione was discovered 100 years ago, we are finding completely new aspects to its biology," Harris said. "There is a lot left to understand but we're hopeful we can translate these discoveries to new therapies."
