I've got you under my skin
Treating skin cancer and skin conditions could soon be as simple as slathering on moisturiser. In a ground-breaking study published online yesterday in the Proceedings of the National Academy of Sciences, researchers at Northwestern University in Illinois show the use of commercial moisturisers to deliver gene regulation technology.
Topical delivery of such technology to cells deep in the skin is extremely difficult because of the skin's formidable defences. But the researchers have found a way to take advantage of drugs consisting of nucleic acids - spherical structures each about 1,000 times smaller than the diameter of a human hair. These acids are able to bind to natural proteins that allow them to traverse the skin and enter cells.
Applied directly to the skin, the drug penetrates all of the its layers and can selectively target disease-causing genes while sparing normal genes. Once in cells, the drug simply flips the switch of the troublesome genes to 'off'.
'This allows us to treat a skin problem where it is manifesting - on the skin,' says co-senior author Dr Amy Paller, chief of dermatology at Northwestern's Feinberg School of Medicine and director of Northwestern's Skin Disease Research Centre. 'We can target our therapy to the drivers of disease, at a level so minute it can distinguish mutant genes from normal genes.'
Early targets of the treatment are melanoma and squamous cell carcinoma (two of the most common types of skin cancer), the common inflammatory skin disorder psoriasis, diabetic wound healing, and epidermolytic ichthyosis, a rare genetic skin disorder that has no effective treatment. Other targets could even include the wrinkles that come with ageing skin.
Professor Chad Mirkin, co-senior author of the paper and director of Northwestern's International Institute for Nanotechnology, first developed the nanostructure platform used in this study in 1996.
The technology is now the basis of powerful commercialised medical diagnostic tools, but this is the first sign that the nanostructures naturally enter the skin. In the study, the nanostructures were combined with a commercial moisturiser and then applied to the skin of mice and humans.
They were designed to target the epidermal growth factor receptor (EGFR), a biomarker associated with a number of cancers.
In both cases, the drug penetrated the skin very deeply, with cells taking up 100 per cent of the nanostructures. They selectively knocked down the EGFR gene, decreasing the production of the problem proteins.
After a month of continued application, there was no evidence of side effects, inappropriate triggering of the immune system or accumulation of the particles in organs.