Antioxidants May Help Fight Mesothelioma

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. 

Sources:
  Surviving Mesothelioma

Immune System May Help Fight Mesothelioma

Proteins and toxins produced by the body’s own immune system could prove to be powerful weapons in the fight against malignant mesothelioma. 

 

Manipulating the immune system to fight cancer is known as immunotherapy.  One type of immunotherapy is utilizing natural immunotoxins, or cell killers, produced by the white blood cells to attack tumors.  Preliminary data shows that a protein produced by these cells called interleukin-4 or IL-4, may have potent cancer-fighting properties.  Researchers with the Pacific Heart Lung & Blood Institute in California are planning studies to test the toxin’s value as a way to combat mesothelioma. 

Their first challenge will be to produce enough IL-4 to conduct tests.  When enough of the immunotoxin can be synthesized according to FDA standards, the researchers plan to test it in combination with chemotherapy, hyperthermia and interferon therapy using mesothelioma cells grown in the laboratory.  If the results of the laboratory studies (in vitro) show promise, the teams will conduct studies of IL-4 in animals (in vivo) and eventually in human subjects.  

Mesothelioma, a rare cancer that attacks the tissues surrounding the lungs and other organs, is extremely difficult treat and survival beyond one year is uncommon.  According to the PHLBI website, if these planned trials prove the efficacy of IL-4, it ‘could be a key to significant progress toward a cure for this dreaded disease’.

Another substance produced by the immune system, interferon, has also shown promising results against mesothelioma in studies conducted at UCLA.  Interferons are messenger proteins that are normally produced to fight certain kinds of infections.  PHLBI researchers believe that, like immunotoxins, interferons may also play a role in fighting abnormal cells like cancer cells, by inhibiting their ability to form blood vessels.  In high does, they have already been shown to help keep melanoma cancer from recurring. 

Plans are in place for upcoming trials to combine interferon with other therapies such as hyperthermia and immune stimulating cytokines to treat mesothelioma cells in the laboratory. Eventually, interferon may even be combined with a COX-2 inhibiting drug such as Celebrex as a ‘maintenance therapy’ to keep mesothelioma tumors in check.  As with IL-4, success in the lab may lead to animal and eventual human testing at UCLA and other centers around the country.

Source:
  Mesothelioma