Can cancer be turned against itself?

Published on Tuesday, 12 March 2013 by Webmaster

Can cancer be turned against itself?
The human immune system can use proteins from melanoma, the most serious type of skin cancer, to kill off cancer cells, according to researchers at Tel Aviv University.

A small group of proteins of the Ras “family” controls a large number of cellular functions, including cell growth, differentiation and survival; because the protein has a hand in cellular division, mutated Ras – which can be detected in one-third of all tumors – contributes to many human cancers by allowing for the rapid growth of diseased cells.

Prof. Yoel Kloog of Tel Aviv University’s neurobiology department, Dr. Itamar Goldstein of TAU’s Sackler Faculty of Medicine and the Sheba Medical Center and colleagues have found cancer-promoting oncogenic Ras can also alert the immune system to the presence of cancer cells. The team published their findings in the Journal of Immunology.

For the first time, the researchers have shown the transfer of oncogenic Ras in human cells from melanoma cells to T cells, which are white blood cells in the immune system.

This transfer allows the immune cells to gather crucial intelligence on what they are fighting and develop the necessary cytokines, or signalling molecules, to kill the melanoma cells.

Kloog suggests that a drug that enhances the transfer of the oncogene from the tumor to the immune cells is a potential therapy to augment the anti-cancer immune response.

Although they found that immune cells often exchange proteins among themselves, the discovery that melanoma cells transfer mutated Ras is an intriguing first. And it's this initial transfer that begins a "positive feedback loop" – the scientists incubated T-cells from patients with human melanoma cells that had originated from tumors. They uncovered a circuit that runs between the cancer and immune cells. Once the melanoma cells pass oncogenic Ras to the T-cells, the T-cells are activated and begin to produce cytokines, which enhances their capacity to kill cancer cells.

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