Retinoic acid liposome-hydrogel: preparation, penetration through mouse skin and induction of F9 mouse teratocarcinoma stem cells differentiation

Retinoic acid (RA), a metabolite of retinol, is one of the most biologically active forms of retinoid and plays vital roles in embryonic development and in the regulation of cell proliferation and differentiation. Knowing that liposomes simulate cell membranes and that hydrogel is an ideal delivery vehicle for topical medicine, liposome-hydrogel is a novel preparation that has synergistic advantages over each component separately. Our objective was to investigate the characteristics of RA liposome-hydrogel. For quality control of the RA-loaded liposomes, we measured their morphology, particle size, Zeta-potential, and entrapment efficiency. Then we determined the viscosity of RA liposome-hydrogel. Next, the diffusion through mouse skin was explored, followed by investigation of the mRNA expression levels of Ker18, REX1, and α-FP using Q-PCR. The results showed that RA liposome-hydrogel penetrates the mouse skin effectively. The permeation rates were: Qn (%) of RA liposome-hydrogel < Qn(%) of RA-loaded liposome < Qn (%) of RA. The mRNA expression levels were dose-dependent and the effective dose decreased between vehicles due to their different release rates. F9 mouse teratocarcinoma stem cells were an ideal model to explore the mechanism of RA liposome-hydrogel in stem cell differentiation.

O ácido retinóico (RA) é um metabolito de retinol. Ele também é uma das formas mais biologicamente ativas de retinóide. Desempenha papel vital no desenvolvimento embrionário e na regulação da proliferação e diferenciação celular. Sabendo-se que lipossomas simulam a membrana das células e que hidrogel é um sistema ideal para o medicamento tópico, o lipossoma-hidrogel é uma nova preparação, que apresenta vantagens sinérgicas em relação a cada um dos componentes separados. Nosso objetivo foi investigar as características de RA lipossoma-hidrogel. A fim de controlar a qualidade do lipossoma carregado com RA, medimos morfologia, tamanho das partículas, potencial zeta e eficiência de retenção. Em seguida, determinou-se a viscosidade de RA lipossoma-hidrogel. Em seguida, avaliou-se a sua difusão através da pele de camundongos, seguida da investigação dos níveis da expressão de mRNA de Ker18, REX e de α-FP, utilizando-se Q-PCR. Os resultados mostraram que RA lipossoma-hidrogel pode penetrar na pele do camundongo de forma eficaz. As taxas de permeação foram: Qn (%) de RA lipossoma-hidrogel<Qn(%) de lipossoma RA- carregado <Qn (%) de RA. Os níveis de expressão de mRNA foram dependentes de dose e a dose efetiva diminuiu entre os veículos devido às diferentes taxas de liberação, As células estaminais de teratocarcinoma F9 de camundongo mostraram-se como modelo ideal para explorar o mecanismo de diferenciaçãode células tronco pelo RA lipossoma-hidrogel.

Novel Molecular Biologic Mechanism of Growth Suppressive Regulation by Retinoid / Interferon in Cervical Cancer Cells / 대한산부인과학회잡지

OBJECTIVE: Retinoic acids (RAs) and interferons (IFNs) have been implicated in the growth regulation of cervical cancer cells, which was suggested by clinical trials and in vitro experiments. However, the molecular mechanisms of growth regulation are not fully defined, The purpose of this study is to assess the effect of RA and/or IFN on human cervical carcinoma cells in vitro and to analyze their action mechanisms in HPV-positive cervical carcinoma cells by molecular biologic studies. METHODS: HPV-positive (CaSki, HeLa), HPV-negative (C33A, HT-3), and non-cervical cancer Cos-1 cell lines were treated with RA and/ar IFN. Their effects on cell growth were evaluated by the cell pmliferation assay and the following BrdU DNA incorporation assay. The molecular mechanism was further investigated by a series of immunoblottings and transient cotransfection assays, which were conducted in HeLa cells and C33A cells using the CAT reporter gene assay. To observe the down regulation of HPV E6/E7 gene expression by RA/IFN, reverse transcription-polymerase chain reaction (RT-PCR) was perforned. RESULTS: The powth of RA-treated cells was less suppressed than that of IFN-treated cells. Combined treatment of RA and IFN leads to additive effect on the growth suppression of HeLa and CaSki cells. The proliferation activity was most severely reduced in Hela cells by treatment of both all-trans-RA (AtRA) and IFN-r. Combined treatment of AtRA/IFN-r causes a great increase in the level of interferon regulatory factor-1 (IRF-1) protein in HeLa cells, whereas no induction of IRF-1 was observed in C33A cells. The CAT gene expression for IRF-1 was greatly induced by IFN-r in HeLa cells. Immunoblotting assays shows the concurrent induction of p21 CDK inhibitor and dephosphorylation of Rb protein in HeLa cells. In RT-PCR, an individual treatment of either RA or IFN reduced HPV E6/E7 mRNA levels and significantly cooperative when both RA and IFN were treated. By deaeasing E6 levels, the p53 level was increased in HeLs cells treated with RA and/or IFN. Transient cotransfection of IRF-1 and p53 as the transcription factors leads to the cooperative activation of a common p21 promoter to regulate the cell cycle. CONCLUSION: RA/IFN suppressed the growth of HPV-positive cervical cancer cells. When they were both treated, additive suppressive effects were observed in cellular proliferation as well as DNA synthesis. The growth suppressive effect is likely to be related to the increased expression of IRF-1 and p21 (antitumoral effect; p53-independent). The down regulation of HPV E6 gene suppression may account for the resultant increase of p53 levels (antiviral effect; p53-dependent). Both induced IRF-1 and p53 cooperatively augument tbe suppession of p21 CDK inhibitor, which results in dephosphorylation of pRb. Although clinical effects are likely complex and may include interactions of in vitro growth inhibitory effects with immunomodulatory and antiangiogeaetic effect, tbese results suggest the optimal clinical role for the combination of RA/IFN in the treatment of cervical canccers.

Retinoic acid and mammalian craniofacial morphogenesis.

Retinoic acid is a morphogenetic signalling molecule in vertebrate embryos, one being known to perform a specific function in organizing the body pattern along the anteroposterior axis. This molecule has especially attracted research attention because retinoic acid treatment will also induce abnormal morphogenesis, particularly in the craniofacial structures. The present review discusses recent molecular insights revealing how the retinoic acid signal is transduced within a cell, specifically focusing on the involvement of cranial neural crest cells in retinoic acid-induced abnormal morphogenesis in the mammalian head.