Recent research has found that vitamin D intake can reduce the aggressiveness of melanoma cancer cells. This study, conducted by researchers from the University of Leeds, found that vitamin D influenced signalling pathway within melanoma cells that slowed their growth and stopped their spreading to the lungs in mice.
The research has been published in Cancer Research, a journal of the American Association for Cancer Research. Although the research is still in its early stages, the findings could, ultimately, lead to new ways to treat melanoma.
According to the data published in this study, the survival rate of melanoma-afflicted patients has nearly doubled in the past four decades, even though 16,000 new cases are diagnosed annually. Around 300 patients are diagnosed with melanoma in its most advanced stage each year in England, at which point the disease is particularly aggressive and difficult to treat. At this late stage, only 55% of patients survive for one year or more, whereas nearly all of those diagnosed at the earliest stage survive to this point.
Previous research has shown that lower levels of vitamin D circulating in the body are linked to worse outcomes for people with melanoma, but researchers have not yet fully understood the mechanisms that cause this.
For this study, lead author Professor Newton-Bishop from the University of Leeds and her team wanted to understand the processes that were being regulated by vitamin D in melanoma cells. They also wanted to study the outcome of having a lack of a protein on the surface of melanoma cells called a vitamin D receptor (VDR) which assists vitamin D in binding to the cell’s surface.
Researchers looked at the expression of the VDR-coding gene in 703 human melanoma tumors and in 353 human melanoma tumours that had metastasised or spread from their primary site. Expression of VDR was then cross-referenced with other patient data, like the tumour thickness and speed of growth. On analysis of the data, researchers also wanted to see if the VDR concentrations in human melanoma cells were correlated to the genetic changes occurring as the tumour becomes more aggressive. Researchers used mouse models to assess whether VDR concentrations altered the cancer’s ability to spread.
The study found that human tumours with low levels of the VDR gene grew faster and a lower activity of genes that control pathways that help the immune system fight cancer cells. Furthermore, tumours with lower VDR levels also had a higher activity of genes linked to cancer growth and spread, especially those controlling the Wnt/β-catenin signalling pathway, which helps to modulate a variety of biological processes within the cell, such as its growth.
While testing in mice, they found that increasing the amount of VDF on the melanoma cells reduced activity of the Wnt/β-catenin pathway and slowed down the growth of the melanoma cells. Cancer was also less likely to spread to their lungs in such cases.
“After years of research, we finally know how vitamin D works with VDR to influence the behaviour of melanoma cells by reducing activity of the Wnt/β-catenin pathway,” Prof Newton-Bishop said. “This new puzzle piece will help us better understand how melanoma grows and spreads, and hopefully find new targets to control it. But what’s really intriguing, is that we can now see how vitamin D might help the immune system fight cancer.”
“We know when the Wnt/β-catenin pathway is active in melanoma, it can dampen down the immune response causing fewer immune cells to reach the inside of the tumour, where they could potentially fight the caner better,” she continued. “Although vitamin D on its own won’t treat cancer, we could take insights from the way it works to boost the effects of immunotherapy, which uses the immune system to find and attack cancer cells.”
Martin Ledwick, head information nurse at Cancer Research UK, further explained, “Vitamin D is important for our muscle and bone health and the NHS already recommends getting 10 micrograms per day as part of our diet or as supplements, especially in the winter months. People who have been newly diagnosed with melanoma should have their vitamin D levels checked and managed accordingly. If you are worried about your vitamin D levels, it’s best to speak to your doctor who can help ensure you are not deficient.”