Labeled as a cancer-causing chemical for decades and declared safe about 15 years ago, saccharin may actually inhibit the growth of cancer cells, according to new research.
The artificial sweetener shows considerable promise for its ability to block an enzyme upregulated in many cancers that helps tumor cells survive and metastasize, researchers say.
After testing its effectiveness on cancer cells, scientists believe saccharin could eventually lead to the development of drugs that treat highly aggressive cancers affecting the breast, liver, prostate, kidney, and pancreas, says Robert McKenna, professor of biochemistry and molecular biology at University of Florida.
The discovery might never have happened if not for Brian Mahon, a curious graduate research assistant who wanted to know how saccharin might affect the enzyme, carbonic anhydrase IX, which is found in aggressive cancers.
But Mahon didn’t want to wait a week for an order of pure saccharin to arrive at the lab. “So we just went to a coffee shop and got some Sweet ‘N Low. I said, ‘Let’s just try it’ and we did and collected some data,” he says.
After doing some initial experimenting, the researchers are collaborating with Susan Frost, professor of biochemistry and molecular biology, to look at saccharin’s effect on breast cancer cells.
The researchers “literally took Sweet ‘N Low and saccharin and showed that the rate of growth of the cancer cell slows down when you added it,” says McKenna, lead author of the new paper that is published in the the journal Bioorganic & Medicinal Chemistry.
How It Works
The researchers discovered that saccharin disrupts carbonic anhydrase IX’s ability to regulate the cancer cell’s pH level—its hydrogen ion concentration. That ultimately makes it harder for the cancer cell to grow and metastasize.
Targeting carbonic anhydrase IX is also an attractive option because it’s not expressed in most other cells throughout the body, meaning that healthy tissue should remain unaffected even as cancer cells are weakened, McKenna says.
Any saccharin-based drugs would probably be used in conjunction with traditional cancer treatments such as chemotherapy and radiation. A saccharin drug would slow the cancer’s growth, providing the opportunity for radiation or chemotherapy to be more effective at killing off the cancer cell.
“It could help make conventional chemotherapy more effective,” McKenna says.
‘Bad Guy’ Turned ‘Good Guy’
The irony of a chemical that was once labeled a potential carcinogen now having potential as an anti-cancer agent wasn’t lost on the research team. Studies in the 1970s linked saccharin to bladder cancer in laboratory rats, according to the National Cancer Institute.
Congress ordered further study and passed a law in 1977 that mandated a warning label. Later studies found that the cancer incidence in rats was irrelevant to humans, leading to a repeal of the labeling requirement in late 2000. The US Food and Drug Administration declared saccharin safe for consumption the following year.
“The public only remembers the negative attention. Saccharin was seen as the bad guy and it’s definitely not the bad guy. It may actually be a good guy,” McKenna says.
The researchers want to further test saccharin’s effectiveness in cancer cells and eventually move to mouse models. This summer, they plan to submit grant requests that will allow additional study and build on the data that have been acquired.
*Image of “sweetner” via Bill & Vicki T/Flickr