New research from a
Philadelphia cancer center suggests antioxidants may be another
important tool in the fight against malignant mesothelioma.
Consumers know antioxidants, such as beta carotene, as dietary supplements which can fight oxidative stress
at the cellular level. Certain beans, blueberries, apples,
cranberries, strawberries, cherries and plums are just some of the foods
that are high in antioxidants. But there are also several antioxidant-based drugs that have a similar effect on cells and are currently being used to treat conditions such as lung disease, diabetes and malaria.
Now, researchers at Thomas Jefferson
Hospital’s Kimmel Cancer Center in Philadelphia have found evidence
that these drugs may also be effective against cancers, such as
mesothelioma. The team 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. Breast cancer patients found to be
missing the Caveolin-1 protein had only a 10 percent chance of surviving
for 5 years, whereas those who did have the protein had a 75 percent
chance of survival.
Loss of the Caveolin-1 protein leads to oxidative stress
in mesothelioma cells, which produces ‘fuel’ for tumor growth. Because
antioxidants fight this stress, and cut off this fuel supply, the
researchers theorize that treating mesothelioma patients with antioxidant
medications might be one way to stop the growth of their tumors.
Currently, antioxidants are not typically used to treat mesothelioma and
other cancers because it is commonly believed that they could counter
the effectiveness of chemotherapy drugs, which cause oxidative stress.
"This study provides the necessary genetic evidence that reducing oxidative stress
in the body will decrease tumor growth,” said lead researcher Michael
P. Lisanti, M.D., Ph.D., professor of cancer biology at Jefferson
Medical College."Now that we have genetic proof that mitochondrial oxidative stress is important for driving tumor growth, we should reconsider using antioxidants… as anti-cancer agents.”
Some of the drugs shown to reduce oxidative stress include the diabetes drugs metformin, a malaria medication called chloroquine and a third agent called N-acetyl cysteine.
In the future they could be used as part of a multi-modality treatment
approach to mesothelioma, which is notoriously difficult to treat.
The study’s findings were published in the online February 15 issue of Cancer Biology & Therapy.
