AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery
Bio Nano Electronics Research Center, Graduate School of Interdisciplinary New Science, Toyo University Kawagoe, Saitama 350-8585, Japan Biotechnology and Bioengineering
(Impact Factor: 4.13).
11/2012; 109(11):2920-31. DOI: 10.1002/bit.24558
Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery. Biotechnol. Bioeng. 2012; 109: 2920-2931. © 2012 Wiley Periodicals, Inc.
Available from: Kun-Ju Lin
- "In this work, liposomes that contain DOX hydrochloride and ABC are prepared and functionalized with an antinucleolin aptamer (AS1411) for targeting DOX-resistant MCF-7 breast cancer cells (MCF-7/ADR) that overexpress nucleolin receptors . AS1411 is a 26-nucleotide guanosine-rich DNA aptamer that can bind to the nucleolin proteins on tumor cells and enter those cells when the nucleolin receptors are shuttled from the plasma membrane into the cytoplasm . Once the liposomes have been internalized by the cancer cells, local heating generates CO 2 bubbles by the decomposition of ABC, rapidly triggering the release of DOX from the liposomal carriers. "
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ABSTRACT: Recent research in chemotherapy has prioritized overcoming the multidrug resistance (MDR) of cancer cells. In this work, liposomes that contain doxorubicin (DOX) and ammonium bicarbonate (ABC, a bubble-generating agent) are prepared and functionalized with an antinucleolin aptamer (AS1411 liposomes) to target DOX-resistant breast cancer cells (MCF-7/ADR), which overexpress nucleolin receptors. Free DOX and liposomes without functionalization with AS1411 (plain liposomes) were used as controls. The results of molecular dynamic simulations suggest that AS1411 functionalization may promote the affinity and specific binding of liposomes to the nucleolin receptors, enhancing their subsequent uptake by tumor cells, whereas plain liposomes enter cells with difficulty. Upon mild heating, the decomposition of ABC that is encapsulated in the liposomes enables the immediate activation of generation of CO2 bubbles, creating permeable defects in their lipid bilayers, and ultimately facilitating the swift intracellular release of DOX. In vivo studies in nude mice that bear tumors demonstrate that the active targeting of AS1411 liposomes can substantially increase the accumulation of DOX in the tumor tissues relative to free DOX or passively targeted plain liposomes, inhibiting tumor growth and reducing systemic side effects, including cardiotoxicity. The above findings indicate that liposomes that are functionalized with AS1411 represent an attractive therapeutic alternative for overcoming the MDR effect, and support a potentially effective strategy for cancer therapy.
Copyright © 2015. Published by Elsevier B.V.
Available from: Fengqian Chen
- "Moreover, AS1411 Apt is resistant to nuclease degradation and remains stable in serum-containing culture medium . It has been successfully adopted as a targeting ligand in several nanoparticles    . In this study, we developed mixed micelles with AS1411 Apt–nucleolin recognition to specifically and effectively deliver anticancer drug PTX. "
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ABSTRACT: Targeted drug delivery coupled with rapid drug release in cytoplasm is a powerful strategy to enhance efficacy and reduce off-target effects of anti-cancer drugs. Herein, we describe a dual-functional mixed micellar system consisting of a pH-responsive copolymer D-α-tocopheryl polyethylene glycol 1000-block-poly-(β-amino ester) (TPGS-b-PBAE, TP) and AS1411 aptamer (Apt) decorated TPGS polymer (Apt-TPGS), which recognizes the over-expressed nucleolin on the plasma membrane of cancer cells. The anti-cancer drug paclitaxel (PTX) was encapsulated in the Apt-mixed micelles, and these drug-loaded micelles had a suitable particle size and zeta potential of 116.3 nm ± 12.4 nm and −26.2 mV ±4.2 mV, respectively. PTX/Apt-mixed micelles were stable at pH 7.4, but they dissociated and quickly released the encapsulated PTX in a weakly acidic environment (pH 5.5). Compared with non-Apt modified mixed micelles, more Apt-modified mixed micelles were internalized in SKOV3 ovarian cancer cells, whereas no significant difference in cellular uptake was observed in normal cells (LO2 cells). The enhanced transmembrane ability of Apt-modified mixed micelles was achieved through Apt-nucleolin interaction. With a synergistic effect of cancer cell recognition and pH-sensitive drug release, we observed significantly increased cytotoxicity and G2/M phase arrest against SKOV3 cells by PTX/Apt-mixed micelles. Intravenous administration of PTX/Apt-mixed micelles for 16 days significantly increased tumor accumulation of PTX, inhibited tumor growth, and reduced myelosuppression on tumor-bearing mice compared with free PTX injection. Therefore, this dual-functional Apt-mixed micellar system is a promising drug delivery system for targeted cancer therapy.
Available from: Jiehua Zhou
- "At tumor sites, the ApNPs induced apoptosis and inhibited spheroid tumor growth. Similarly, Aravind et al.116 functionalized PLGA-lecithin-PEG nanoparticles that were loaded with the anticancer drug Paclitaxel, using AS1411 DNA aptamers to specifically target tumor cells that overexpressed nucleolin receptors. "
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ABSTRACT: One hundred years ago, Dr. Paul Ehrlich popularized the "magic bullet" concept for cancer therapy in which an ideal therapeutic agent would only kill the specific tumor cells it targeted. Since then, "targeted therapy" that specifically targets the molecular defects responsible for a patient's condition has become a long-standing goal for treating human disease. However, safe and efficient drug delivery during the treatment of cancer and infectious disease remains a major challenge for clinical translation and the development of new therapies. The advent of SELEX technology has inspired many groundbreaking studies that successfully adapted cell-specific aptamers for targeted delivery of active drug substances in both in vitro and in vivo models. By covalently linking or physically functionalizing the cell-specific aptamers with therapeutic agents, such as siRNA, microRNA, chemotherapeutics or toxins, or delivery vehicles, such as organic or inorganic nanocarriers, the targeted cells and tissues can be specifically recognized and the therapeutic compounds internalized, thereby improving the local concentration of the drug and its therapeutic efficacy. Currently, many cell-type-specific aptamers have been developed that can target distinct diseases or tissues in a cell-type-specific manner. In this review, we discuss recent advances in the use of cell-specific aptamers for targeted disease therapy, as well as conjugation strategies and challenges.
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