Researchers have demonstrated that the nutritional supplement mannose sugar, can both slow tumor growth and enhance the effects of chemotherapy in mice with multiple types of cancer. The findings were recently published in Nature.
In this study, the researchers found that mannose can interfere with glucose to reduce how much glucose cancer cells can use.
“Tumors need a lot of glucose to grow, so limiting the amount they can use should slow cancer progression. The problem is that normal tissues need glucose as well, so we can’t completely remove it from the body,” explained Kevin Ryan, lead author from the Cancer Research UK Beatson Institute (Glasgow).
“In our study, we found a dosage of mannose that could block enough glucose to slow tumor growth in mice, but not so much that normal tissues were affected. This is early research, but it is hoped that finding this perfect balance means that, in the future, mannose could be given to cancer patients to enhance chemotherapy without damaging their overall health,” Ryan continued.
Firstly, the team of researchers examined how mice with pancreatic, lung or skin cancer responded when mannose was added to their drinking water and given as an oral treatment. They found that adding the supplement significantly slowed the growth of tumors and did not cause any obvious side effects.
The scientists then tested how mannose could also affect cancer treatment by treating mice with cisplatin and doxorubicin. From this, they demonstrated that mannose enhanced the effects of chemotherapy, slowing tumor growth, reducing the size of tumors and even increasing the lifespan of some mice.
Several other cancer types, including leukaemia, osteosarcoma, ovarian and bowel cancer, were also investigated. Researchers grew cancer cells in the lab and then treated them with mannose to see whether growth was affected.
Some cells responded well to the treatment, while others did not. Additionally, the team showed that cells with low levels of the enzyme phosphomannose isomerase (PMI) were more sensitive to mannose treatment than cells with high levels of PMI, making PMI a good indicator of how effective treatment was.
Ryan added: “Our next step is investigating why treatment only works in some cells, so that we can work out which patients might benefit the most from this approach. We hope to start clinical trials with mannose in people as soon as possible to determine its true potential as a new cancer therapy.”
Mannose is sometimes used for short periods to treat urinary tract infections, but its long-term effects have not been investigated. It’s important that more research is conducted before mannose is used in cancer patients.
Martin Ledwick (Cancer Research UK) concluded: “Although these results are very promising for the future of some cancer treatments, this is very early research and has not yet been tested in humans. Patients should not self-prescribe mannose as there is a real risk of negative side effects that haven’t been tested for yet. It’s important to consult with a doctor before drastically changing your diet or taking new supplements.”