"Antioxidants have been associated with cancer reducing effects-beta carotene, for example-but the mechanisms, the genetic evidence, has been lacking," Dr. Lisanti said. "This study provides the necessary genetic evidence that reducing oxidative stress in the body will decrease tumor growth."

Currently, anti-cancer drugs targeting oxidative stress are not used because is it commonly thought they will reduce the effectiveness of certain chemotherapies, which increase oxidative stress.

"We are not taking advantage of the available drugs that reduce oxidative stress and autophagy, including metformin, chloroquine and N-acetyl cysteine," Dr. Lisanti said. "Now that we have genetic proof that oxidative stress and resulting autophagy are important for driving tumor growth, we should re-consider using antioxidants and autophagy inhibitors as anti-cancer agents."

The diabetic drug metformin and chloroquine, which is used for the prevention and treatment of malaria, prevent a loss of Cav-1 in cancer associated fibroblasts (which is due to oxidative stress), functionally cutting off the fuel supply to cancer cells.

This research also has important implications for understanding the pathogenesis of triple negative and tamoxifen-resistance in ER-positive breast caner patients, as well as other epithelial cancers, such as prostate cancers.

"Undoubtedly, this new genetically tractable system for cancer associated fibroblasts will help identify other key genetic 'factors' that can block tumor growth," Dr. Lisanti said.

Source: Thomas Jefferson University