Could we stop cancer by blocking sugar?
Researchers may have found a novel way to protect people at risk for cancer by blocking sugar intake into cancer cells. Obesity and diabetes are both linked to an increased risk for developing cancer and both are also linked to higher chances that cancer will progress.
The researchers use fruit flies because they can provide information about multiple genes as it relates to disease instead of looking at just one gene and a singular disease.
“Previous research has established a strong correlation between metabolic diseases and pancreatic, breast, liver, and colon cancers, but we have not determined how tumors grow so aggressively in this environment if they do not have the energy provided by glucose,” Ross Cagan, PhD, Professor of Developmental and Regenerative Biology at Mount Sinai said in a press release.
We know our cells use sugar for energy, but with insulin resistance that often stems from obesity and is a component of metabolic syndrome and for people with diabetes, the cells no longer absorb glucose. Instead sugar remains in the blood stream.
Given the above, scientists have been baffled about how cancer that feeds on sugar can thrive when there isn't any glucose being delivered to the cells.
Cagan explains, “Using our fruit fly model, we discovered how tumors overcome insulin resistance in the body and turn metabolic dysfunction to their advantage."
For the first part of the study, the scientists engineered fruit flies to develop small tumors of the head. Next they fed the flies a diet high in sugar to promote insulin resistance.
They discovered that over time the tumors themselves became insulin resistant. When the researchers tweaked things further to promote more insulin resistance they found the cancer cells started growing aggressively.
Now the scientists had three separate pathways to target: the cancer related Ras and Src genes that the fruit flies were engineered to express that reacts with sugar to cause insulin sensitivity in the tumors specifically, an important pathway called Wingless/Wnt, that they activated to increase tumor cells’ insulin receptors and sugar.
The next step was to go to work finding compounds that block the cascade of events.
They treated the fruit flies with the diabetes treatment acarbose, a compound called AD81 that inhibits the cancer pathway and a drug called pyrvinium that inhibits Wnt.
The combination of treating the cancer and blocking sugar with the anti-diabetic drug stopped the progression of cancer and decreased the size of the tumors.
Cagan said insulin sensitivity causes sugar to "pour into tumors" because it has nowhere else to go.
An interesting note is that research has shown the most commonly prescribed diabetes drug metformin seems to protect people from cancer. The popular diabetes drug is currently being investigated for prevention and treatment of the disease, specifically in high risk individuals.
Blocking sugar with the diabetes drug and two other compounds stopped cancer tumors in its tracks. The next step is to see if the same cascade of events happens in humans. The research team plans to test compounds that block sugar and stop tumors from growing in hopes of finding a new way to prevent and treat cancer.