R&D News: Pancreatic cancers use fructose to fuel growth
Although it is widely known that cancers use glucose, a simple sugar, to fuel their growth, this is the first time a link has been shown between fructose and cancer proliferation, said the study's senior author, Anthony Heaney, an associate professor of medicine and neurosurgery and a Jonsson Cancer Center researcher.
Mr Heaney, who also serves as co-director of the pituitary tumor and neuroendocrine program at UCLA, said: “The bottom line is the modern diet contains a lot of refined sugar including fructose, and it's a hidden danger implicated in a lot of modern diseases, such as obesity, diabetes and fatty liver. In this study, we show that cancers can use fructose just as readily as glucose to fuel their growth.”
Sources of fructose in the western diet include cane sugar (sucrose) and high-fructose corn syrup (HFCS), a corn-based sweetener. HFCS accounts for more than 40 percent of the caloric sweeteners added to foods and beverages, and it is by far the most frequently used sweetener in American soft drinks.
Food companies use HFCS - a mixture of fructose and glucose - because it is inexpensive, easy to transport and keeps foods moist. And because of its excessive sweetness, it is cost-effective for companies to use small quantities of HCFS in place of more expensive sweeteners or flavorings.
In his study, Mr Heaney and his team took pancreatic tumors from patients and cultured and grew the malignant cells in Petri dishes. They then added glucose to one set of cells and fructose to another. Using mass spectrometry, they were able to follow the carbon-labeled sugars in the cells to determine what, exactly, they were being used for and how.
Mr Heaney found that the pancreatic cancer cells could easily distinguish between glucose and fructose, which are very similar structurally, and contrary to conventional wisdom, the cancer cells metabolized the sugars in very different ways.
In the case of fructose, the pancreatic cancer cells used the sugar in the transketolase-driven non-oxidative pentose phosphate pathway to generate nucleic acids, the building blocks of RNA and DNA, which the cancer cells need to divide and proliferate.
The study states that traditionally, glucose and fructose have been considered as interchangeable monosaccharide substrates that are similarly metabolized, and little attention has been given to sugars other than glucose.
Mr Heaney said that while this study was done in pancreatic cancer, these finding may not be unique to that cancer type.
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