Mitochondria produce energy for the cell, but have a number of other important roles.Credit: Professors P. Motta & T. Naguro/Science Photo Library
Cancer cells use mitochondria stolen from immune cells to spread and escape detection, according to a study published this week in Cell Metabolism1.
Scientists have struggled to fully explain how some tumour cells can spread to and survive in lymph nodes, which are packed with cells that should be able to kill them.
A new kind of mitochondrion
Derick Okwan-Duodu, an immunologist and clinical pathologist at Stanford University in California, looked for answers in the emerging field of mitochondrial transfer, in which the tiny cellular energy factories known as mitochondria move from one cell to another.
Okwan-Duodu and his colleagues found that cancer cells implanted in mice acquired mitochondria from a variety of immune cells. They did so at equal rates irrespective of whether they were implanted into the lymph node or skin.
Stolen batteries
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. Silencing genes associated with this pathway reduced the ability of cancer cells to migrate to lymph nodes in mice, Okwan-Duodu and his colleagues found.
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.
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