A specific type of cancer known as squamous cell carcinoma is remarkably more dependent on sugar for their energy supply compared to other types.
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‘A specific type of cancer known as squamous cell carcinoma is remarkably more dependent on sugar for their energy supply compared to other types.’
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Kim and his collaborators initially set out to investigate differences in metabolism between two major subtypes of non-small cell lung cancer -- adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). About one quarter of all lung cancers are SqCC, which has been difficult to treat with targeted therapies, Kim said. 
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The research team, which included a Dallas high school student who interned in Kim’s lab, first tapped into a large government database called The Cancer Genome Atlas, which maps information about 33 types of cancer gathered from more than 11,000 patients.
Based on that data, they found that a protein responsible for transporting glucose -- a kind of sugar -- into cells was present in significantly higher levels in lung SqCC than in lung ADC. The protein, called glucose transporter 1, or GLUT1, takes up glucose into cells, where the sugar provides a fundamental energy source and fuels cell metabolism. GLUT1 is also necessary for normal cell function, such as building cell membranes.
"Prior to this study, it was thought that the metabolic signatures of these two types of lung cancers would be similar, but we realized that they are very different," Kim said. "These findings lend credence to the idea that cancer is not just one disease, but many diseases that have very different characteristics."
With elevated GLUT1 implicated in SqCC’s appetite for sugar, the researchers looked for additional evidence by examining human lung tissue and isolated lung cancer cells, as well as animal models of the disease.
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The researchers also investigated the effect of a GLUT1 inhibitor in isolated lung cancer cells and mice with both types of non-small cell lung cancer.
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"Taken in total, our findings indicate that GLUT1 could be a potential target for new lines of drug therapy, especially for the squamous subtype of cancer."
In addition to squamous cell lung cancer, the team found that GLUT1 levels were much higher in four other types of squamous cell cancer: head and neck, esophageal and cervical.
"These are very different organs and tissues in the body, but somehow squamous cell cancers have a very similar commonality in terms of glucose uptake," Kim said. "This type of cancer clearly consumes a lot of sugar. One of our next steps is to look at why this is the case."
An upcoming study by Kim’s group will examine the effect of a sugar-restricted diet on the progression of lung cancer in an animal model of the disease. The U.S. Department of Agriculture estimates that in 2015, on average, each American consumed more than 75 pounds of refined sugar, high fructose corn syrup and other sweeteners combined.
"As a culture, we are very addicted to sugar," Kim said. "Excessive sugar consumption is not only a problem that can lead to complications like diabetes, but also, based on our studies and others, the evidence is mounting that some cancers are also highly dependent on sugar. We’d like to know from a scientific standpoint whether we might be able to affect cancer progression with dietary changes."
Source-Eurekalert