The role of liposomal delivery in cutaneous DNA repair

Transdermal delivery systems in cosmetics

Transdermal delivery systems have been intensively studied over the past 2 decades, with the focus on overcoming the skin barrier for more effective application of pharmaceutical and cosmetic products. Although the cosmeceutical industry has made a substantial progress in the development and incorporation of new and effective actives in their products, the barrier function of the skin remains a limiting factor in the penetration and absorption of these actives. Enhancement via modification of the stratum corneum by hydration, acting of chemical enhancers on the structure of stratum corneum lipids, and partitioning and solubility effects are described. This review summarizes the advances in the development and mechanisms of action of chemical components that act as permeation enhancers, as well as the advances in appropriate vehicles, such as gels, emulsions, and vesicular delivery systems, that can be used for effective transdermal delivery.

Skin cancer prevention: a review of current topical options complementary to sunscreens

The incidence of non-melanoma skin cancer (NMSC) is dramatically increasing worldwide, despite the increased use of improved sunscreens. In 2014, the Surgeon General estimated that 2.2-5.0 million people were treated annually for NMSC. As the number of newly diagnosed skin cancers continues to rise, there is a need for additional preventative measures beyond sunscreens. Several newer topical products that focus on boosting DNA repair, modulating DNA transcription, decreasing inflammation and selectively targeting precancerous cells may play an important role in future skin cancer prevention.

UV-specific DNA repair recombinant fusion enzyme: a new stable pharmacologically active principle suitable for photoprotection

BACKGROUND

UV radiation can produce mutations in skin cells and correlates strongly with the onset of actinic keratoses and basal and squamous cell carcinomas. Xeroderma pigmentosum (XP) is a heritable disease characterized by an extreme sensitivity of skin to UV radiation. Recently, studies in cultured cells as well as in XP patients have demonstrated that the recombinant T4 endonuclease V UV-specific endonuclease could enhance repair of UV-induced photoproducts.

OBJECTIVE

We aimed to obtain a stable UV-specific DNA recombinant endonuclease, pharmacologically active in mammalian cells so as to be used in treatment and prophylaxis of sun damage.

METHODS

The UV-specific DNA endonuclease gene obtained from Micrococcus luteus, was fused to a leader peptide and expressed (alphaUveA), refolded and purified. A construction under the control of an eukaryotic promoter was used to transfect XP fibroblasts deficient in DNA damage repair. Transformed cells were UV irradiated and cell survival was assessed.

RESULTS

alphaUveA was obtained as a highly active UV-specific repair enzyme stable for at least 2 years. XP fibroblasts transfected with alphaUveA gene increased the resistance to UV radiation and, in consequence, cell survival.

CONCLUSION

alphaUveA is stable and pharmacologically active in human cells. The topical administration of this long-term stable new active principle could help diminish the risks of skin cancer after sun exposure.

Topical transfection using plasmid DNA in a water-in-oil nanoemulsion

Expression plasmids encoding chloramphenicol acetyltransferase (CAT) or human interferon-alpha2 cDNA were formulated in water-in-oil nanoemulsions and applied to murine skin. The histological location of transfected cells was assessed by in situ DNA PCR and showed that the deposition of plasmid DNA was primarily in follicular keratinocytes. Transgene expression in the skin was monitored for 24-72 h, following topical application of either single or multiple daily doses by quantitative RT-PCR and ELISA. It was found that transgene expression was optimal at 24 h following topical application of a single dose of water-in-oil nanoemulsion containing plasmid DNA. Dose-response studies using a total dose of 3, 10 or 30 microg of plasmid DNA suggested that topical transfection using nanoemulsions is subject to both threshold and saturation effects. None of the cationic liposome formulations tested as controls mediated transgenic protein expression at levels higher than background values of the ELISAs used to assay transgenic protein. Single and multiple dose experiments using human interferon-alpha2 as a transgene indicated that the efficiency of nanoemulsion mediated transfection was most effective in the context of normal versus atrophic hair follicles. In addition, the total amount of human interferon-alpha2 present in skin appeared to accumulate as a consequence of multiple dosing. Histologic evaluation of treated skin showed no overt signs of toxicity or irritation associated with the short-term application of the nanoemulsions. The results suggest that water-in-oil nanoemulsions can be used to facilitate transfection of follicular keratinocytes in vivo.