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Eriya Kenjo,
Tomohiro Asai,
Norihito Yonenaga, Hidenori Ando,
Takayuki Ishii,
Kentaro Hatanaka,
Kosuke Shimizu,
Yugo Urita,
Takehisa Dewa,
Mamoru Nango,
Hideo Tsukada,
Naoto Oku
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ABSTRACT: Novel polycation liposomes decorated with cyclic(Cys-Arg-Gly-Asp-D-Phe) peptide (cyclicRGD)-polyethylene glycol (PEG) (RGD-PEG-polycation liposomes (PCL)) were previously developed for cancer therapy based on RNA interference. Here, we demonstrate the in vivo delivery of small interfering RNA (siRNA) to tumors by use of RGD-PEG-PCL in B16F10 melanoma-bearing mice. Pharmacokinetic data obtained by positron emission tomography showed that cholesterol-conjugated siRNA formulated in RGD-PEG-PCL markedly accumulated in the tumors. Delivered by RGD-PEG-PCL, a therapeutic cocktail of siRNAs composed of cholesterol-conjugated siRNAs for c-myc, MDM2, and vascular endothelial growth factor (VEGF) were able to significantly inhibit the growth of B16F10 melanoma both in vitro and in vivo. These data suggest that targeted delivery of siRNAs by use of RGD-PEG-PCL has considerable potential for cancer treatment.
Biological & Pharmaceutical Bulletin 01/2013; 36(2):287-291. · 1.66 Impact Factor
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ABSTRACT: BACKGROUND: RNA interference has been receiving much attention as a novel therapeutic strategy. Especially, microRNA (miRNA) is promising as novel nucleic-acid medicine, since miRNA could suppress a series of protein expression which relates a specific event such as angiogenesis. Presently, we used dicetyl phosphate-tetraethylenepentamine-based polycation liposomes (TEPA-PCL) as a delivery system for miR-92a, one of the miRNAs regulating angiogenesis, and attempted to deliver miR-92a to angiogenic endothelial cells for the development of cancer therapy by antiangiogenesis. METHODS: Cholesterol-grafted miR-92a (miR-92a-C) was bound to TEPA-PCL, and the ratio of nitrogen of TEPA-PCL to phosphorus of miR-92a-C (N/P ratio) was optimized. This complex was transfected into human umbilical vein endothelial cells (HUVECs), and the intracellular localization of miR-92a-C was observed under a confocal laser-scanning microscope by use of FITC-labeled miR-92a-C. After transfection of HUVECs with miR-92a-C/TEPA-PCL, the expression of miR-92a-target proteins (e.g. integrin α5, MKK4, S1P1) was examined by Western blotting, and tube formation assay was performed. RESULTS: The complex of miR-92a-C with TEPA-PCL was formed, and miR-92a-C remained stable with TEPA-PCL at the N/P ratio of 10. After transfection of HUVECs with miR-92a-C complex, miR-92a-C was spread into the whole cytoplasm of the cells without the change of cellular morphology, and the expression of several proteins encoded by miR-92a-target genes was suppressed. Furthermore, capability to form capillary tubes was impaired in complex-treated HUVECs. CONCLUSIONS: We developed miR-92a delivery system into angiogenic endothelial cells by use of TEPA-PCL. These results suggest that miR-92a-C/TEPA-PCL is promising for treatment of tumors by suppressing angiogenesis. Copyright © 2012 John Wiley & Sons, Ltd.
The Journal of Gene Medicine 12/2012; · 2.48 Impact Factor
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ABSTRACT: An accelerated blood clearance (ABC) phenomenon is induced by repeated injections of poly(ethylene glycol)-modified (PEGylated) liposomes. We previously indicated that the phenomenon was induced by polymeric micelles possessing PEG chains like as liposomes, although, the induction mechanism of the ABC phenomenon is not fully elucidated. In the present study, we investigate whether repeat-injection of the polymeric micelles having PEG chains trigger the phenomenon or not. Two polymeric micelles, PM-30 (polymeric micelles with 33.6nm in diameter) and PM-75 (76.2nm), were prepared with PEG-poly[Asp(pentyl)] and PEG-poly[Asp(nonyl)], respectively. We firstly examined the ABC-triggering effect of these micelles, and observed that both polymeric micelles, especially PM-75, induced the production of anti-PEG IgM antibody in treated mice. Then, PM-30 or PM-75 was preadministered into mice as a preconditioning. Seven days later, AlexaFluor594-labeled PM-30 or PM-75 was administered to determine the susceptibility of the phenomenon. As a result, rapid clearance of AlexaFluor594-labeled PM-75 from the bloodstream and accumulation in the liver were observed in PM-75 pretreated mice. Although, the ABC phenomenon of AlexaFluor594-labeled PM-30 was less obvious in PM-30 pretreated mice. Our present results indicated that the repeated injections of polymeric micelles caused the ABC phenomenon in a size-dependent manner.
International journal of pharmaceutics 04/2012; 432(1-2):75-9. · 2.96 Impact Factor
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ABSTRACT: In the development of nucleic acid medicines such as small interfering RNA (siRNA) drugs, one problem is how to study the pharmacokinetics and pharmacodynamics, since the precise in vivo behavior of siRNA is hard to detect. In this research, to establish a highly sensitive detection system of siRNA biodistribution in the whole body, the technology of positron imaging was applied. First, a one-step synthetic method in which double-stranded siRNA was directly labeled by a positron emitter, (18)F, was developed. By using [(18)F]-labeled siRNA ([(18)F]-siRNA), the complex of siRNA and polycation liposomes (PCL) containing dicetylphosphate tetraethylenepentamine (TEPA-PCL) was prepared. Then, the biodistribution of the siRNA after intravenous administration to mice was analyzed by planar positron imaging system (PPIS). As a result, whereas naked [(18)F]-siRNA was immediately excreted in mouse bladder after administration, the complex with cationic liposome (CL) was trapped in the lungs. Furthermore, [(18)F]-siRNA carried with PEGylated CL (PL) was distributed throughout the body, suggesting that it circulated in the bloodstream for an extended period of time. Additionally, PET imaging revealed more detailed biodistribution of the siRNA than in vivo imaging system (IVIS) because PET imaging is not affected by the depth variation of target tissues. On the other hand, to induce high accumulation of siRNAs against c-myc, MDM2, and VEGF in tumor tissue, a tumor-targeting probe, RGD peptide, was grafted at the top of PEG chain in PEGylated TEPA-PCL and the effect of the complex on experimental lung metastasis of B16 melanoma was examined. The complex suppressed the progression of tumor. We believe that the positron imaging data would support the development of siRNA agent for clinical use.
YAKUGAKU ZASSHI 01/2012; 132(12):1373-81. · 0.37 Impact Factor
