We use the blanket term “sugar” to describe a variety of nutrients found naturally in different types of fruits and vegetables. One important natural sugar, mannose, has gained some attention for its potential anticancer properties. Indeed, recent preclinical studies have demonstrated the ability of mannose to reduce inflammation and suppress tumor growth and metastasis. Additionally, mannose can render cancer cells more susceptible to cancer treatments, like chemotherapy.
While questions remain on this pathway in cancer, experts have studied the effects of mannose in bees for decades. These studies have found a lethal impact of mannose on bees, a phenomenon known as honeybee syndrome. When bees consume large amounts of mannose, the intracellular buildup exceeds what can be metabolized. The bees are unable to survive the resulting metabolic deficiency.
Could mannose, the sugar that kills honeybees, help fight cancer? A recent paper published in eLife addresses this question. The study focused on the ability of mannose to stop cancer cells from growing and expanding, a biological process known as proliferation.
The researchers used specially engineered cells from fibrosarcoma, a type of cancer that forms in the soft, fibrous connective tissue around bone and muscles. Using these cells, the researchers recapitulated honeybee syndrome by allowing large amounts of mannose to enter the cells. When the mannose influx exceeds metabolic capacity, cell proliferation slows substantially. The researchers also found that the cancer cells with high mannose influx died more efficiently when treated with chemotherapy.
The study found that the reduced cell proliferation seen in cells with high mannose influx resulted from an inability to produce sufficient amounts of deoxyribonucleoside triphosphates (dNTPs), the building blocks of DNA. Thus, when intracellular mannose levels increase, the cells cannot produce the components needed for DNA replication, and therefore cell growth is hindered.
This study demonstrates that controlling the influx of mannose into cancer cells could provide a potential approach to combination cancer treatments. Further research is needed to prove how efficaciously this approach could be when applied to human cancer therapies.
Sources: Front Pharmacol, Front Immunol, Nature, Science, eLife