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.
PHLBI Medical Research, Pacific Heart Lung & Blood Institute website. “High Dose Interferon Prolongs Time to Recurrence in Melanoma”, National Cancer Institute website