A molecule in immune cells which restrains the growth of melanoma in mice, is found in a milestone study by researchers from Brigham and Women`s Hospital (BWH) in Boston. The new finding may help shape the future treatment for the lethal skin cancer.
Melanoma is the most deadly form of skin cancer, which kills more than nine thousand people each year in the US alone. The condition is curable if detected and treated early. The researchers found that high expression of a cell-signaling molecule, known as interleukin-9, in immune cells inhibits melanoma growth.
In mice study, researchers examined mice lacking the gene that is accountable for development of an immune cell known as TH17 (T helper cell 17), they found that mice had significant resistance to melanoma tumour growth. The study suggested that obstructing the TH17 cell pathway could favour tumour inhibition. They also observed that the mice expressed high amounts of interleukin-9.
Subsequently, researchers treated melanoma-bearing mice with TH9 (T helper cell 9), an immune cell which generates interleukin-9. They found that mice treated with TH9 also had an intense resistance to melanoma growth. It is the first study of its kind that reported an anti-tumour effect of TH9 cells.
Besides, researchers were able to identify TH9 cells in skin as wells as normal human blood, particularly in skin-resident memory T cells and memory T cells in peripheral blood mononuclear cells. On the contrary, TH9 cells were either absent or present at very low levels in individuals with melanoma.
Study co-author Rahel Purwar, a PhD scholar at BWH`s Department of Dermatology, stated these were unexpected results, which led to examine a possible contribution of interleukin-9 to cancer growth suppression. The new finding paves the way for future studies to assess the role of interleukin-9 and TH9 cells in human cancer therapy.
Lead author Thomas Kupper, chair of the BWH Department of Dermatology, explained they hope that study findings results will translate the treatment of melanoma patients, but much work still needs to be done. Other cell-signalling molecules have been used in treating melanoma, but, this study is the first to investigate the role of interleukin-9 in melanoma tumour immunity.
The study was published in the journal Nature Medicine.