A new research study has shown that chondroitin sulfate, a dietary supplement taken for osteoarthritis, selectively promotes growth of a specific type of melanoma cell in mice. Approximately half of melanoma cells have the B-raf gene mutation known as V600E. The research team confirmed that chondroitin sulfate increases growth of melanoma cells with the mutation but other melanoma cells were unaffected. The findings have not been confirmed in human studies but oncologists and individuals with melanoma should still be aware of the risk of taking the supplement. The study was published in Molecular Cell.
In the experiments, the chondroitin levels given to mice with V600E tumors were comparable to the amount an individual would take when using it as a dietary supplement. The researchers also observed that mice fed chrondroitin sulfate exhibited resistance to vemurafenib, a commonly used B-raf inhibitor drug for V600E melanoma.
"We want to be cautious about these results, and they should be followed up," he says. "There is not a lot of hard data on dietary supplement use. We found that we had to add a line to the forms melanoma patients fill out about their histories, since we weren't asking before."
The effect was discovered while colleagues were screening melanoma cells for enzymes that could aid in tumor growth. The enzyme chondroitin sulfate glucuronyltransferase, or CSG, was identified, which is necessary for generating chondroitin sulfate polymer.
Overall, the findings suggests that the supplement must be involved in a signaling pathway related to melanoma cell growth but more studies are needed to understand its exact role. The paper also identifies CSG as a potential drug target for melanoma but inhibitor compounds have yet to be found and tested for safety and side effects.
Image: Chondroitin sulfate promotes tumor growth. Image courtesy Lin et all, 2018.