A study reveals new insights into mannose, a sugar with cancer-fighting properties. The study links the "bee syndrome" observed in honeybees to mannose's ability to slow cancer cell replication and improve the effectiveness of chemotherapy.
New research on mannose and its anticancer effects
A new study conducted by Sanford Burnham Prebys and the International Cancer Research Institute in Osaka has revealed new insights into the anticancer properties of mannose. Mannose is a vital sugar involved in several physiological processes in the body, and it is known to inhibit the growth of cancer cells. The study, published on July 18, 2023 in the journal eLife, suggests that mannose could serve as a valuable adjuvant therapy for cancer.
"In addition to other treatments, this sugar may deliver an extra hit to cancer," said study co-author Dr. Hudson Freeze, director of the Human Genetics Program at Sanford Burnham Prebys University. "And because mannose occurs naturally throughout the body, it could improve cancer treatment without any unwanted side effects."
The role of mannose in glycosylation
Mannose is a sugar that attaches to proteins. This process helps stabilize their structure and facilitates their interactions with other molecules. This process, known as glycosylation, is essential to life, and any malfunction of glycosylation has been linked to rare but often serious life-threatening human diseases.
"The most promising therapeutic use of mannose so far is in the treatment of congenital disorders of glycosylation, which cause severe symptoms throughout the body," Freeze said. "But we believe there may be a way to harness mannose to fight cancer and other diseases."
Mannose, Bees, and Cancer
Although mannose has been shown to inhibit the growth of several cancers in the laboratory, the underlying mechanism has remained elusive. To address this question, the team investigated an unusual property of mannose that had been observed in an unlikely subject: honeybees.
"Mannose has been known for over a century to be lethal to bees because they cannot process mannose the way humans do—it's been called the 'bee syndrome,'” Freeze said. "We wanted to see if there was any relationship between bee syndrome and the anti-cancer properties of mannose, which could lead to a whole new approach to fighting cancer."
Experimental results and future implications
The research team successfully replicated bee syndrome using genetically engineered human cancer cells from fibrosarcoma, a rare cancer that affects connective tissue. They found that in the absence of an enzyme necessary to metabolize mannose, the cells replicated slowly and were significantly more sensitive to chemotherapy.
"We found that triggering bee syndrome in these cancer cells made them unable to synthesize the building blocks of DNA and replicate normally," Freeze said. "This helps explain the anti-cancer effects of mannose that we observed in the laboratory."
The researchers caution that while exploiting bee syndrome has the potential to serve as a promising adjuvant cancer treatment, because the effect depends on key metabolic processes, more research is needed to determine which types of cancer respond the most to mannose.
Potential of glycosylated sugars in cancer therapy
"If we can find cancers that have lower activity of the enzyme that processes mannose, then treating them with mannose could provide enough of a boost to make chemotherapy more effective," Freeze said. "A lot of people think that you can always find a cure for a disease, but sometimes you find biology that might be useful for a treatment, and then you have to find a disease that matches that."
At the same time, the study highlights the broader potential of glycosylation in cancer therapy, an area of research that is still in its infancy.
"The glycobiology of sugar metabolism in cancer cells remains an unexplored frontier, and it could be an untapped treasure trove of potential therapeutics waiting to be discovered," Freeze added.
