J Gene Med. 2013 Jan;15(1):20-7. doi: 10.1002/jgm.2690.

Development of a miR-92a delivery system for anti-angiogenesis-based cancer therapy.

Ando H1, Okamoto A1, Yokota M1, Shimizu K1, Asai T1, Dewa T2, Oku N1

1Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, Shizuoka, Japan

2Department of Life and Materials Engineering, Nagoya Institute of Technology, Nagoya, Japan



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.

Keywords: angiogenesis; cancer therapy; microRNA; miR-92a; polycation liposomes

Copyright © 2012 John Wiley & Sons, Ltd.

PMID: 23239404



For development of effective cancer therapy by systemic administration of anticancer drugs, antiangiogenesis is a crucial event to allow them to induce potential therapeutic effects. Tumor angiogenic vessels are known to be formed by random and abnormal sprouting from pre-existing vessels, and to be induced by some pro-angiogenic agents that are highly expressed in the tumor (Jain RK, Science 2005). Therefore, it is difficult to deliver an anticancer drug to entirety of the tumor via bloodstream. On the other hand, it was reported that some antiangiogenic agents induce vascular normalization in the tumor; and transiently normalize the structure and function of the tumor vasculature (Chauhan VP, et al., Nat Nanotechnol 2012). It means that an anticancer drug should be delivered to entirety of the tumor after vascular normalization by the treatment with some antiangiogenic agents, and enhances the therapeutic effect. In fact, combination therapy of an anticancer drug with certain antiangiogenic agent was often reported to induce significant suppression of the tumor growth compared to the treatment with the drug alone (Diop-Frimpong B, et al., Proc Natl Acad Sci U S A 2011; Chauhan VP, et al., Nat Commun 2013).

To induce effective antiangiogenesis in the tumor, miR-92a has a high potency as an antiangiogenic agent. It is well known that cancer is caused by accumulation of the multiple genetic mutations. Thus, the treatment with some therapeutic agents targeting to single proangiogenic molecule might be insufficient to impair the activity of the signaling pathways regulating angiogenesis. On the other hand, since miR-92a regulates the expression of a series of target-molecules involving angiogenesis, miR-92a would induce effective antiangiogenic actions in the tumor via the knockdown of target signaling pathways (Bonauer A, et al., Science 2009).

In present study, we developed miR-92a delivery system for novel cancer therapy via antiangiogenesis, and are convinced that miR-92a-based cancer therapy should have much potential to induce vascular normalization in the tumor by effective antiangiogenesis.

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