Discovery of protein link may lead to brain tumour treatment
US researchers have identified a link between two proteins found in brain tumours, a discovery which could one day lead to a treatment for a particularly aggressive form of the disease.
Scientists at the Massachusetts Institute of Technology (MIT) have uncovered a previously unknown connection between a protein called EGFRvIII and a receptor called c-Met. Receptors are proteins that transmit signals within cells by recognising and sticking to other proteins.
EGFRvIII is a mutated form of the EGFR protein and causes cells to grow and divide uncontrollably and is found in around a quarter of glioblastoma multiforme (GBM) tumours, an aggressive brain cancer that is currently hard to treat.
Researchers found that whenever EGFRvIII is activated, the c-Met receptor is also active, despite the fact that it is normally switched off in adult cells.
The c-Met receptor has already been implicated in very invasive types of lung and breast cancer so the discovery of a link between c-Met and EGFRvIII could help to explain why these brain tumours are so aggressive.
Lead author Paul Huang, a graduate student in biological engineering, said: "It seems that it is not the activation of one receptor that results in cancer. It's the action of multiple receptors that leads to the tumours we see."
The finding provides an explanation for why previous attempts to treat patients by inhibiting EGFRvIII have had little effect.
Mr Huang added: "A potential way to overcome this is to attack multiple targets instead of just one."
Lead researcher Forest White, associate professor of biological engineering at MIT, said that it is still unclear how EGFRvIII activates c-Met.
"Our data shows that as EGFRvIII is activated, c-Met is activated as well. Whether it's direct or indirect is something that we are currently deciphering."
The researchers treated tumour cells with drugs to inhibit both EGFRvIII and c-Met and found that much lower doses were required to kill the cells than when one or other of the drugs was given in isolation.
They hope that the finding, published in an early online edition of the Proceedings of the National Academy of Sciences, will guide drug developers by alerting them to the need to target both proteins at once.