Building upon work they completed more than a decade ago, a team of researchers has come up with a new drug that can mimic the effects of tanning in humans without the need for exposure to harmful ultraviolet radiation – a breakthrough detailed Tuesday in the journal Cell Reports.
While the research is still in its early stages, according to Science News, it could be the first step towards the creation of a new sunless tanning cream that triggers the production of the dark form of the pigment melanin, which absorbs UV radiation and helps protect skin cells from damage.
“It has a potent darkening effect,” Dr. David Fisher, chief of the Department of Dermatology at Massachusetts General Hospital and one of the authors of the new paper, explained to the BBC News website “Under the microscope it’s the real melanin, it really is activating the production of pigment in a UV-independent fashion.”
The new research builds on a previous study, led by Dr. Fisher and colleagues from MGH and the Dana-Farber Cancer Institute in Boston, in which they applied a plant extract to mice which had skin similar to that of red-headed, fair-skinned people who had difficulty tanning. Doing so stimulated production of the dark form of melanin, the researchers found, and when exposed to UV rays, the mice were less likely to become sunburned and develop skin tumors.
“There was an obvious interest in asking, could this be applied to human skin?” Dr. Fisher told Science News. While the plant extract used in the original study was unable to penetrate human skin (which is much thicker than that of mice), his team discovered a new enzyme which could block an inhibitor of melanin production and cause skin to look tanned in just eight days.
Study could result in a new way to prevent skin cancer
The enzyme in question, salt-inducible kinases (SIKs), were known to regulate the transcription of a protein, the study authors explained in a statement. Previous research conducted by a team of Japanese scientists had demonstrated that inhibiting SIK expression activated pigmentation in mice, prompting Dr. Fisher’s team to investigate the matter further.
They used a previously identified SIK inhibitor on the same type of mice featured in their 2006 study, and found that the creatures’ skin grew increasingly darker after daily treatments with the substance. However, that compound was found to have a limited effect on human skin samples, leading the team to turn to study co-author Dr. Nathanael Gray of DFCI for assistance.
Dr. Gray and his colleagues developed a new class of small-molecule SIK inhibitors which was tested by Dr. Fisher’s team and found to be far more capable of penetrating human skin cultures than the previous substance. The new inhibitor was administered topically to skin samples daily for eight days, and examination of the treated samples confirmed that dark melanin pigments had been produced and deposited near the surface in patterns consistent with a suntan.
“We are excited about the possibility of inducing dark pigment production in human skin without a need for either systemic exposure to a drug or UV exposure to the skin,” Dr. Fisher said. But as he told BBC News, his team was motivated primarily by the lack of progress in the treatment and prevention of skin cancer, which he called a source of “very significant frustration.”
“Our real goal is a novel strategy for protecting skin from UV radiation and cancer,” he told the British media outlet. “Dark pigment is associated with a lower risk of all forms of skin cancer – that would be really huge.” While he cautioned that the researchers still need to ensure that their new substance is safe to use, he said that it was “possible” that this new SIK inhibitor “may lead to new ways of protecting against UV-induced skin damage and cancer formation.”
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