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Background: Gene therapy is a new approach to discover and treat many diseases. It has attracted considerable attention from researchers in the last decades. The gene therapy through RNA interference has been considered one of the most recent and revolutionary approaches used in individualized therapy. In the last years, we have witnessed the rapid development in the field of the gene silencing and knockdown by topical siRNA. Its application in gene therapy has become an attractive alternative for drug development. Methods: This article will address topical delivery of siRNA as a promising treatment for skin disorders. An update on the advances in siRNA-based nanocarriers as a powerful therapeutic strategy for several skin diseases will be discussed giving emphasis on in vitro evaluations. Results: Through the in-depth review of the literature on the use of siRNAs for skin diseases we realize how widespread this use is. We have also realized that nanoparticles as non-viral vectors are increasingly being explored. Skin diseases where the use of siRNA has been explored most are skin cancer (melanoma and nonmelanoma), psoriasis, vitiligo, dermatitis and leprosy. But we also report here other diseases where the use of siRNA has been growing as acne, alopecia areata, cutaneous leishmaniasis, mycoses, herpes, epidermolysis bullosa and oculocutaneous albinism. Also highlighted, the first clinical trial of siRNA for cutaneous diseases, aimed at Pathyounychia Congenita. Conclusion: The treatment of skin diseases based on topical delivery of siRNA, which act by inhibiting the expression of target transcripts, offers many potential therapeutic advantages for suppressing genes into the skin.

O tratamento de câncer baseado em plataformas multifuncionais tem sido, de forma geral eficientes, pois tratam-se de terapias que atuam de forma simultânea em mais de uma das vias da patogênese no câncer. Neste sentido, a co-administração de fármacos antimetabólicos, tal como o 5-Fluorouracil (FU) e small interference RNA (siRNA) específicos para alvos do câncer, representam uma estratégia racional para o tratamento do câncer de pele. O 5FU é um fármaco que possui importante aplicação no tratamento tópico do câncer de pele. No entanto, sua baixa meia vida e altas toxicidades cutânea e sistêmica impede a adesão correta ao tratamento. Um dos grandes alvos para tratamentos de tumores, são as proteínas da família BCL-2, estas impedem que a cascata da apoptose se ative. Uma das maneiras mais eficazes para reduzir a super expressão de proteínas, é o uso de small interfering RNA (siRNA) específicos, que impedirão que o RNA mensageiro seja traduzido na proteína alvo. Entretanto, aspectos físico-químicos e biológicos do 5FU e de siRNA impedem uma adequada biodisponibilidade no tecido cutâneo após aplicação tópica. Desta forma, o desenvolvimento de sistemas nanoestruturados para a co-administração do 5FU e de siRNA específico para proteína BCL-2, representa uma alternativa para a redução dos efeitos adversos e o aumento da segurança terapêutica. Assim, o presente trabalho objetivou desenvolver e caracterizar carreadores lipídicos nanoestruturados (CLN) para encapsular o 5FU e complexar com siRNA BCL-2, além de sua avaliação in vitro para perfis de liberação, permeação cutânea, retenção cutânea, bem como viabilidade e transfecção celular, além de ensaios ex vivo visando conhecer as características de interação com a pele humana, e por fim, avaliação da atividade antiproliferativa e apoptótica. Os resultados obtidos demonstram que o CLN desenvolvido possui diâmetros de partículas, índices de polidispersão e potencial zeta adequados para exercer sua função, se mostrou estável, além de ter encapsulado o 5FU e complexado com o siRNA de maneira eficiente. O CLN apresentou perfis de permeação e retenção cutânea in vitro promissoras para aplicação tópica dos agentes terapêuticos em questão. A viabilidade celular indicou que o CLN desenvolvido possui IC50 menores para as linhagens tumorais, além de apresentarem transfecção celular comparado com o controle Lipofectamina 2000®. Os ensaios ex vivo foram indispensáveis para entender o comportamento do CLN desenvolvido na pele humana e o mesmo impediu o estrato córneo de descamar, devido ao filme lipídico oclusivo que formou, sendo esta uma observação inédita no modelo hOSEC. Os ensaios de atividade, por ELISA, Western Blot e qRT-PCR se complementaram e apontaram que o CLN foi capaz de reduzir significativamente, a proliferação das linhagens tumorais e o RNAm para a proteína BCL-2. Estes resultados em conjunto cooperam entre si para que o CLN em questão seja considerado promissor para o tratamento tópico do câncer de pele The treatment of cancer based on multifunctional platforms has been generally efficient because they are therapies that act simultaneously in more than one of the pathogenesis pathways in cancer. Therefore, the co-administration of antimetabolic drugs, such as 5-Fluorouracil (FU) and small interference RNA (siRNA) specific for cancer targets, represents a rational strategy for the treatment of skin cancer. The 5FU is a drug that has important application in the topical treatment of skin cancer. However, its low half-life and high cutaneous and systemic toxicity prevents correct treatment adherence. One of the major targets for tumor treatments, are the BCL-2 family proteins, which prevent the cascade of apoptosis from activating. One of the most effective ways to reduce protein overexpression is to use specific RNA (siRNA), which will prevent messenger RNA from being translated into the target protein. However, physico-chemical and biological aspects of 5FU and siRNA limit their prevent adequate bioavailability in cutaneous tissue after topical application. Thus, the development of nanostructured systems for co-administration of 5FU and specific siRNA for BCL-2 protein represents an alternative for reducing adverse effects and increasing therapeutic safety. Thus, the present work aimed to develop and characterize nanostructured lipid carriers (NLC) to transport 5FU and to complex with BCL-2 siRNA, in addition to its in vitro evaluation for profiles of release, cutaneous permeation, cutaneous retention, as well as cell viability and transfection , in addition to ex vivo tests aiming to know the interaction characteristics with the human skin, and, finally, evaluation of the antiproliferative and apoptotic activity. The results obtained demonstrate that the developed NLC has particle diameters, polydispersion indices and zeta potential adequate to perform its function, it has shown to be stable, besides encapsulating the 5FU and complexing with the siRNA efficiently. The NLC presented promising in vitro skin permeation and retention profiles for topical application. Cell viability indicated that the developed NLC has lower IC 50 for the tumor cell lines, besides presenting cellular transfection compared to the control Lipofectamina 2000®. The ex vivo assays were indispensable to understand the behavior of NLC developed in the human skin and the same prevented the stratum corneum from peeling due to the occlusive lipid film that formed, this was an unprecedented observation in the hOSEC model. The activity assays, by ELISA, Western Blot and qRT-PCR were complemented and indicated that NLC was able to significantly reduce proliferation of tumor lines and mRNA for BCL-2 protein. These results together cooperate with each other so that the NLC in question is considered promising for the topical treatment of skin cancer

Summary Copolymers are polymers consisting of different repeat units and their production is usually motivated by the changing of polymers properties. An important application are the transportation of drugs within the organism with the aim of controlling the release of the substance. The synthesis of these new copolymers is based on simple semi-synthesis and low cost. The synthetic routes are based on the interaction of the graft copolymer (PMMA-g-PEG) with a variety of reagents such as acetic anhydride, acetic acid, methyl iodide, sulfuric acid and hydrochloric acid. The products from these reactions of esterification, methylation, acetylation and halogenation will be characterized by Fourier-transforminfrared spectroscopy (FTIR). The use of this technique allowed us to detect the main absorption bands related to the CO bonds, C-Cl, R-COOR and CO, thus confirming the efficiency of modification reactions of the graft copolymer chain.