Cancer might evade immune defences by stealing mitochondria

"The findings represent "an entirely new mechanism by which mitochondrial transfer helps cancer progress", says Cynthia Reinhart-King, a bioengineer at Rice University in Houston, Texas. The benefits to cancer cells held up even when the researchers destroyed the stolen mitochondria's ability to produce the energy-carrying molecule ATP, showing that the organelles' energy production is not crucial to these effects, Okwan-Duodu says."

"This mitochondrial theft seemed to have at least two effects that benefited cancer cells. Not only did it weaken the immune cells from which these powerful organelles were stolen, but it also triggered a beneficial molecular pathway in the cancer cells that gained them. The cancer cells that took up the mitochondria began expressing genes linked to the type I interferon pathway, an immune signalling cascade that might help cells evade the immune system and support lymph-node invasion."

Cancer cells implanted in mice acquired mitochondria from a variety of immune cells at similar rates in lymph node and skin. Mitochondrial transfer weakened the donor immune cells and triggered gene expression in recipient cancer cells linked to the type I interferon signalling pathway. Activation of that pathway correlated with increased ability of cancer cells to migrate to lymph nodes, and silencing associated genes reduced lymph-node migration in mice. The metastasis-promoting effects persisted even when the stolen mitochondria could not produce ATP, indicating non-energetic roles for transferred mitochondria in promoting immune evasion and spread.

Read at Nature