Harnessing T-Cells to Fight Mesothelioma

Cancer researchers in Australia are harnessing the power of disease-fighting T-cells in the ongoing battle with mesothelioma.

Mesothelioma is a virulent cancer of the membrane that surrounds the lungs and lines the abdomen. The response of the body’s immune system to mesothelioma and other cancers is complex. Mesothelioma tumors in mice and people produce large numbers of Regulatory (Treg) T cells. While Treg cells are typically thought of as one of the body’s ways of fighting disease, the latest research suggests that, in some cases, turning these cells ‘off’ might be more effective against cancer than letting them do their job.

In the newest study of Treg cells, they were shown to act as important “mediators” of the body’s anti-tumor response to malignant mesothelioma. When Treg cells are removed from mesothelioma tumors, the result is slower tumor growth and the release of a different type of T-cell – the anti-tumor effector T-cell. Drawing on the results of previous T-cell/mesothelioma studies, the Australian cancer team says driving the immune system by manipulating Treg cells might even offer a way to increase the effectiveness of chemotherapy.

Summarizing their findings in a recent issue of Cancer Microenvironments, the researchers write that Treg cells are “critical mediators of the anti-tumor immune response to mesothelioma and potential targets for anti-tumor immunotherapy.” But they also caution that the timing and dosage of Treg cell manipulation needs to be carefully optimized to make the best use of their power.

Manipulation of the body’s immune system to fight mesothelioma and other diseases is known as immunotherapy. It is of particular interest to mesothelioma researchers because this cancer, a response to asbestos exposure, is highly resistant to conventional therapies. In recent months, immunotherapy studies around the world have targeted a variety of immunomodulatory molecules including MUC1, B7-H3, and the chemokine CCL2. Previous studies on the immune system and mesothelioma have found a definite correlation between anti-tumor immune responses and survival, regardless of what other types of treatments were being used. Studies are ongoing.

Sources:

Ireland, DJ, “The Role of Regulatory T Cells in Mesothelioma”, February 1, 2012, Cancer Microenvironments, Epub ahead of print. Bograd, AJ, “Immune responses and immunotherapeutic interventions in malignant pleural mesothelioma”, November 2011, Cancer Immunology and Immunotherapy, pp. 1509-1527.