A team of cancer scientists has discovered a new aspect of 'metabolic transformation', the process whereby tumour cells adapt and survive under conditions that would kill normal cells.
Their findings show how breast cancer cells can thrive when deprived of their usual diet of glucose (sugar) and oxygen by turning to fatty acids for energy generation.
"Our results demonstrate that a protein not previously associated with breast cancer is involved in helping these cells to adapt to starvation conditions and to continue their uncontrolled growth," said Tak Mak, principal investigator and Director, The Campbell Family Institute for Breast Cancer Research at Princess Margaret Hospital.
The researchers used an anticancer drug called rapamycin to block a molecular signalling pathway within breast cancer cells that stimulates sugar metabolism. However, instead of dying of starvation, the cells continued to multiply.
The team also observed an increase in these cells of carnitine palmitoyltransferase 1C (CPT1C), a protein usually found only in the brains of healthy individuals. Moreover, cells engineered to produce high levels of CPT1C were also able to adapt their metabolism as a survival technique.
"In other words, the cancer cells acted like cheaters on a diet and found a new food source in fatty acids," said Mak.
"The fact that CPT1C becomes expressed under conditions of metabolic stress highlights the resilience of cancer cells. They are able to adapt to environmental challenges and find alternative sources of food in order to flourish where healthy cells would not survive."
"Our discovery that deprivation of either sugar or oxygen spurs CPT1C expression in tumour cells marks this protein as a potential target for new drug development," Mak added.
The study was recently published in Genes and Development.