Credits: DAVID BLOOM/QMI AGENCY
The researchers found that tumour cells alter glycosylation, the process whereby carbohydrates attach to proteins. When tumour cells add GlcNAc, a specific sugar that is pronounced glick-nack, to the enzyme phosphofructokinase (PFK1), the cells bypassed the normal process cells undergo to do work. Instead, the tumour cells grew larger and continued to survive.
The scientists found that human breast- and lung-tumour tissues had GlcNAc-related glycosylation at levels two and four times higher than the patients' normal tissue. And, while working with mice that had been injected with human lung-cancer cells, researchers found that when they replaced the existing PFK1 enzymes in the cells with either the normal PFK1 enzyme or a mutant form that could not be glycosylated, the mice with the mutant form of the enzyme showed decreased tumour growth.
Linda Hsieh-Wilson, leader of the CalTech research team, said the GlcNAc mechanism is not the first scientists have observed that allows tumour cells to survive, but that unlike the other mechanisms it's not a genetic alteration or mutation.
"What's unique here is that the addition of GlcNAc is dynamic and reversible," Hsieh-Wilson said in a release. This allows a cancer cell to more rapidly alter its metabolism depending on the environment it encounters."
More research is necessary, but the discovery could lead to the development of compounds that prevent PFK1 from being glycosylated.
The study appeared in this week's issue of the journal Science.