Consumers have long valued antioxidants, such as beta carotene, as dietary supplements which can combat oxidative stress at the cellular level. Fruit such as blueberries, apples, cranberries, strawberries, cherries and plums are particularly high in antioxidants.
Now researchers at the Kimmel Cancer Center have linked antioxidant-based drugs, which have a similar effect oxidative stress as certain types of fruit, to the suppression of cancers such as mesothelioma.
Their research has showed that the loss of a tumor-suppressing protein known as Caveolin-1 leads to tumor growth and is an important predictor of cancer outcomes. The loss of this protein leads to oxidative stress in mesothelioma cells which promotes tumor growth.
The scientists believe that because antioxidants fight this stress, and cut the fuel supply for tumor growth, anti-oxidant medications could stop the tumor growth of patients suffering from malignant mesothelioma.
In a statement on the cancer centre’s website, lead researcher Michael Lisanti, professor of cancer biology at Jefferson Medical College, said: “This study provides the necessary genetic evidence that reducing oxidative stress in the body will decrease tumor growth.
“Now that we have genetic proof that mitochondrial oxidative stress is important for driving tumor growth, we should reconsider using anti-oxidants… as anti-cancer agents.”
The study revealed that breast cancer patients who lacked the Caveolin-1 protein had only a 10 percent chance of surviving five years compared with a 75 percent chance of survival for those who had the protein.
Antioxidants are seldom used to treat mesothelioma and other cancers because of fears that they reduce the effectiveness of chemotherapy drugs which cause oxidative stress.
Several antioxidant-based drugs are currently used to treat conditions such as lung disease, diabetes and malaria.
Mesothelioma, or malignant mesothelioma, is a rare form of cancer that develops from the protective lining that covers many of the body's internal organs, the mesothelium.
Incidence of malignant mesothelioma currently ranges from about 7 to 40 per 1,000,000 in industrialized Western nations, according to a report in The New England Journal of Medicine. A key factor determining incidence is historic exposure to asbestos which is known to cause the condition.
Some believe the US incidence of malignant mesothelioma may have peaked at 15 per 1,000,000 in 2004.
Between 1940 and 1979, about 27.5m people were occupationally exposed to asbestos, according to a report from the Rand Institute for Civil Justice.
Some estimates suggest the US death rate from mesothelioma rose from 2,000 per year in 1980 to about 3,000 in the late 1990s.
Cancer Biology & Therapy
February 15, 2011, Volume 11
Title: 'Caveolin-1 and mitochondrial SOD2 (MnSOD) function as tumor suppressors in the stromal microenvironment: A new genetically tractable model for human cancer associated fibroblasts'
Authors: Trimmer, Casey at al.