The team at the University of Texas at Dallas were looking for simpler ways to tell one kind of cancer cell from another.
Some kinds of lung cancer tumors really like sugar, and blocking that sweet tooth might offer a way to treat the disease, researchers reported Friday.
They discovered that squamous cell tumors — which account for about 25 percent to 30 percent of lung cancer tumors — slurp up more sugar than other types.
“It has been suspected that many cancer cells are heavily dependent on sugar as their energy supply, but it turns out that one specific type — squamous cell carcinoma — is remarkably more dependent,” said Dr. Jay Jung-whan Kim, who led the study team.
“Adenocarcinoma is much less dependent on sugar.”
All cells use sugar, in the form of glucose, to one degree or another. But some use more than others.
Their finding, published in the journal Nature Communications, also suggests a possible treatment. Kim’s team found that the cancer cells also had higher-than-average levels of a protein called glucose transporter 1a protein or GLUT1. GLUT1 is commonly by used cells all through the body to pull in glucose.
It might be possible to find ways to starve these cancer cells of the sugar they crave, either through diet or by blocking GLUT1, Kim said.
“We looked at this from several different experimental angles, and consistently, GLUT1 was highly active in the squamous subtype of cancer,” Kim said.
“Our findings indicate that GLUT1 could be a potential target for new lines of drug therapy, especially for the squamous subtype of cancer.”
Lung cancer kills more than 155,000 people a year in the U.S. alone. “Lung cancer is by far the leading cause of cancer death among both men and women; about one out of four cancer deaths are from lung cancer,” the American Cancer Society says.
‘Addicted to sugar’
Cancer experts now know that cancer is not a single disease, and even the names of different cancer types are a little misleading. Lung cancer may start in the lungs, but there are several different types and subtypes and they have more to do with genetic mutations and the particular type of lung tissue affected than the fact that they’re first seen in the lung.
Kim’s team found that other types of squamous cell cancers, including head and neck, esophageal and cervical, tumors, also had very active levels of GLUT1.
They also found a link with smoking, the leading cause of lung cancer.
“Lung squamous cell carcinoma has been primarily linked to smoking. Indeed, we found that GLUT1 expression was strongly associated with smoking,” they wrote.
“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.”
His team is now studying effects of a sugar-restricted diet on lung cancer in mice.
The researchers will have to take care in trying to target GLUT1. A rare condition called GLUT1 deficiency causes slow growth in the brain and skull during infancy and early childhood. They can suffer seizures, difficulty controlling their arms and legs and diminished IQ.
Several other studies have indicated that people who consume more sugar have a higher risk of cancer — especially breast cancer and pancreatic cancer.
In 2016 a team at M.D. Anderson Cancer Center in Houston found people who ate the most foods with a high glycemic index — which can raise blood sugar levels — were about 50 percent more likely to have lung cancer than people who reported eating less of that kind of food.
The World Health Organization says people should try to get no more than five percent of calories from sugar.
Health officials routinely advise Americans to eat less processed sugar.
“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.”