Technological advances in both siRNA (small interfering RNA) and whole genome sequencing have demonstrated great potential in translating genetic information into siRNA-based drugs to halt the synthesis of most disease-causing proteins. Despite its powerful promises as a drug, siRNA requires a sophisticated delivery vehicle because of its rapid degradation in the circulation, inefficient accumulation in target tissues and inability to cross cell membranes to access the cytoplasm where it functions. Lipid nanoparticle (LNP) containing ionizable amino lipids is the leading delivery technology for siRNA, with five products in clinical trials and more in the pipeline. Here, we focus on the technological advances behind these potent systems for siRNA-mediated gene silencing.
Vaishnaw, A.K.; Gollob, J.; Gamba-Vitalo, C.; Hutabarat, R.; Sah, D.; Meyers, R.; de Fougerolles, T.; Maraganore, J. A status report on rnai therapeutics. Silence 2010, 1, 14, doi:10.1186/1758-907X-1-14.
[3]
McManus, M.T.; Sharp, P.A. Gene silencing in mammals by small interfering rnas. Nat. Rev. Genet. 2002, 3, 737–747, doi:10.1038/nrg908.
[4]
Miele, E.; Spinelli, G.P.; di Fabrizio, E.; Ferretti, E.; Tomao, S.; Gulino, A. Nanoparticle-based delivery of small interfering RNA: Challenges for cancer therapy. Int. J. Nanomed. 2012, 7, 3637–3657.
[5]
De Fougerolles, A.; Vornlocher, H.P.; Maraganore, J.; Lieberman, J. Interfering with disease: A progress report on siRNA-based therapeutics. Nat. Rev. Drug Discov. 2007, 6, 443–453, doi:10.1038/nrd2310.
[6]
Whitehead, K.A.; Langer, R.; Anderson, D.G. Knocking down barriers: Advances in sirna delivery. Nat. Rev. Drug Discov. 2009, 8, 129–138, doi:10.1038/nrd2742.
[7]
Manoharan, M.; Akinc, A.; Pandey, R.K.; Qin, J.; Hadwiger, P.; John, M.; Mills, K.; Charisse, K.; Maier, M.A.; Nechev, L.; et al. Unique gene-silencing and structural properties of 2'-fluoro-modified sirnas. Angew. Chem. Int. Ed. Engl. 2011, 50, 2284–2288.
[8]
Manoharan, M. RNA interference and chemically modified small interfering RNAs. Curr. Opin. Chem. Biol. 2004, 8, 570–579, doi:10.1016/j.cbpa.2004.10.007.
[9]
Engels, J.W. Gene silencing by chemically modified sirnas. New Biotechnol. 2013, 30, 302–307, doi:10.1016/j.nbt.2012.07.002.
[10]
Soutschek, J.; Akinc, A.; Bramlage, B.; Charisse, K.; Constien, R.; Donoghue, M.; Elbashir, S.; Geick, A.; Hadwiger, P.; Harborth, J.; et al. Therapeutic silencing of an endogenous gene by systemic administration of modified sirnas. Nature 2004, 432, 173–178, doi:10.1038/nature03121.
[11]
Allen, T.M.; Cullis, P.R. Liposomal drug delivery systems: From concept to clinical applications. Adv. Drug Deliv. Rev. 2012, 65, 36–48, doi:10.1016/j.addr.2012.09.037.
[12]
Daka, A.; Peer, D. RNAi-based nanomedicines for targeted personalized therapy. Adv. Drug Deliv. Rev. 2012, 64, 1508–1521, doi:10.1016/j.addr.2012.08.014.
Jayaraman, M.; Ansell, S.M.; Mui, B.L.; Tam, Y.K.; Chen, J.; Du, X.; Butler, D.; Eltepu, L.; Matsuda, S.; Narayanannair, J.K.; et al. Maximizing the potency of sirna lipid nanoparticles for hepatic gene silencing in vivo. Angew. Chem. Int. Ed. Engl. 2012, 51, 8529–8533, doi:10.1002/anie.201203263.
[15]
Huang, L.; Liu, Y. In vivo delivery of rnai with lipid-based nanoparticles. Annu. Rev. Biomed. Eng. 2011, 13, 507–530, doi:10.1146/annurev-bioeng-071910-124709.
[16]
Burnett, J.C.; Rossi, J.J.; Tiemann, K. Current progress of siRNA/shRNA therapeutics in clinical trials. Biotechnol. J. 2011, 6, 1130–1146, doi:10.1002/biot.201100054.
[17]
Barros, S.A.; Gollob, J.A. Safety profile of RNAi nanomedicines. Adv. Drug Deliv. Rev. 2012, 64, 1730–1737, doi:10.1016/j.addr.2012.06.007.
[18]
Tabernero, J.; Shapiro, G.I.; LoRusso, P.M.; Cervantes, A.; Schwartz, G.K.; Weiss, G.J.; Paz-Ares, L.; Cho, D.C.; Infante, J.R.; Alsina, M.; et al. First-in-humans trial of an RNA interference therapeutic targeting vegf and ksp in cancer patients with liver involvement. Cancer Discov. 2013, 3, 406–417, doi:10.1158/2159-8290.CD-12-0429.
[19]
Alabi, C.; Vegas, A.; Anderson, D. Attacking the genome: Emerging sirna nanocarriers from concept to clinic. Curr. Opin. Pharmacol. 2012, 12, 427–433, doi:10.1016/j.coph.2012.05.004.
[20]
Crawford, R.; Dogdas, B.; Keough, E.; Haas, R.M.; Wepukhulu, W.; Krotzer, S.; Burke, P.A.; Sepp-Lorenzino, L.; Bagchi, A.; Howell, B.J. Analysis of lipid nanoparticles by cryo-em for characterizing siRNA delivery vehicles. Int. J. Pharm. 2011, 403, 237–244, doi:10.1016/j.ijpharm.2010.10.025.
Belliveau, N.M.; Huft, J.; Lin, P.J.C.; Chen, S.; Leung, A.K.K.; Leaver, T.J.; Wild, A.W.; Lee, J.B.; Taylor, R.J.; Tam, Y.K.; et al. Microfluidic synthesis of highly potent limit-size lipid nanoparticles for in vivo delivery of sirna. Mol. Ther. Nucleic Acids 2012, 1, e37, doi:10.1038/mtna.2012.28.
[23]
Zhigaltsev, I.V.; Maurer, N.; Edwards, K.; Karlsson, G.; Cullis, P.R. Formation of drug-arylsulfonate complexes inside liposomes: A novel approach to improve drug retention. J. Control. Release 2006, 110, 378–386, doi:10.1016/j.jconrel.2005.10.011.
[24]
Semple, S.C.; Klimuk, S.K.; Harasym, T.O.; Dos Santos, N.; Ansell, S.M.; Wong, K.F.; Maurer, N.; Stark, H.; Cullis, P.R.; Hope, M.J.; et al. Efficient encapsulation of antisense oligonucleotides in lipid vesicles using ionizable aminolipids: Formation of novel small multilamellar vesicle structures. Biochim. Biophys. Acta 2001, 1510, 152–166, doi:10.1016/S0005-2736(00)00343-6.
[25]
Maurer, N.; Wong, K.F.; Stark, H.; Louie, L.; McIntosh, D.; Wong, T.; Scherrer, P.; Semple, S.C.; Cullis, P.R. Spontaneous entrapment of polynucleotides upon electrostatic interaction with ethanol-destabilized cationic liposomes. Biophys. J. 2001, 80, 2310–2326, doi:10.1016/S0006-3495(01)76202-9.
[26]
Hafez, I.M.; Maurer, N.; Cullis, P.R. On the mechanism whereby cationic lipids promote intracellular delivery of polynucleic acids. Gene Ther. 2001, 8, 1188–1196, doi:10.1038/sj.gt.3301506.
[27]
Xu, Y.; Szoka, F.C., Jr. Mechanism of DNA release from cationic liposome/DNA complexes used in cell transfection. Biochemistry 1996, 35, 5616–5623, doi:10.1021/bi9602019.
[28]
Bailey, A.L.; Cullis, P.R. Modulation of membrane fusion by asymmetric transbilayer distributions of amino lipids. Biochemistry 1994, 33, 12573–12580, doi:10.1021/bi00208a007.
[29]
Heyes, J.; Palmer, L.; Bremner, K.; MacLachlan, I. Cationic lipid saturation influences intracellular delivery of encapsulated nucleic acids. J. Control. Release 2005, 107, 276–287, doi:10.1016/j.jconrel.2005.06.014.
[30]
Maier, M.A.; Jayaraman, M.; Matsuda, S.; Liu, J.; Barros, S.; Querbes, W.; Tam, Y.K.; Ansell, S.M.; Kumar, V.; Qin, J.; et al. Biodegradable lipids enabling rapidly eliminated lipid nanoparticles for systemic delivery of RNAi therapeutics. Mol. Ther. 2013, 21, 1570–1578, doi:10.1038/mt.2013.124.
[31]
Allen, T.M. The use of glycolipids and hydrophilic polymers in avoiding rapid uptake of liposomes by the mononuclear phagocyte system. Adv. Drug Deliv. Rev. 1994, 13, 285–309, doi:10.1016/0169-409X(94)90016-7.
Klibanov, A.L.; Maruyama, K.; Torchilin, V.P.; Huang, L. Amphipathic polyethyleneglycols effectively prolong the circulation time of liposomes. FEBS Lett. 1990, 268, 235–237, doi:10.1016/0014-5793(90)81016-H.
[34]
Webb, M.S.; Saxon, D.; Wong, F.M.; Lim, H.J.; Wang, Z.; Bally, M.B.; Choi, L.S.; Cullis, P.R.; Mayer, L.D. Comparison of different hydrophobic anchors conjugated to poly(ethylene glycol): Effects on the pharmacokinetics of liposomal vincristine. Biochim. Biophys. Acta 1998, 1372, 272–282, doi:10.1016/S0005-2736(98)00077-7.
Song, L.Y.; Ahkong, Q.F.; Rong, Q.; Wang, Z.; Ansell, S.; Hope, M.J.; Mui, B. Characterization of the inhibitory effect of PEG-lipid conjugates on the intracellular delivery of plasmid and antisense DNA mediated by cationic lipid liposomes. Biochim. Biophys. Acta 2002, 1558, 1–13, doi:10.1016/S0005-2736(01)00399-6.
[39]
Monck, M.A.; Mori, A.; Lee, D.; Tam, P.; Wheeler, J.J.; Cullis, P.R.; Scherrer, P. Stabilized plasmid-lipid particles: Pharmacokinetics and plasmid delivery to distal tumors following intravenous injection. J. Drug Target. 2000, 7, 439–452, doi:10.3109/10611860009102218.
Judge, A.; McClintock, K.; Phelps, J.R.; Maclachlan, I. Hypersensitivity and loss of disease site targeting caused by antibody responses to pegylated liposomes. Mol. Ther. 2006, 13, 328–337, doi:10.1016/j.ymthe.2005.09.014.
[43]
Semple, S.C.; Harasym, T.O.; Clow, K.A.; Ansell, S.M.; Klimuk, S.K.; Hope, M.J. Immunogenicity and rapid blood clearance of liposomes containing polyethylene glycol-lipid conjugates and nucleic acid. J. Pharmacol. Exp. Ther. 2005, 312, 1020–1026.
[44]
Heyes, J.; Hall, K.; Tailor, V.; Lenz, R.; MacLachlan, I. Synthesis and characterization of novel poly(ethylene glycol)-lipid conjugates suitable for use in drug delivery. J. Control. Release 2006, 112, 280–290, doi:10.1016/j.jconrel.2006.02.012.
[45]
Chonn, A.; Semple, S.C.; Cullis, P.R. Association of blood proteins with large unilamellar liposomes in vivo. Relation to circulation lifetimes. J. Biol. Chem. 1992, 267, 18759–18765.
[46]
Cullis, P.R.; Chonn, A.; Semple, S.C. Interactions of liposomes and lipid-based carrier systems with blood proteins: Relation to clearance behaviour in vivo. Adv. Drug Deliv. Rev. 1998, 32, 3–17, doi:10.1016/S0169-409X(97)00128-2.
[47]
Mendez, A.J.; He, J.L.; Huang, H.S.; Wen, S.R.; Hsia, S.L. Interaction of rabbit lipoproteins and red blood cells with liposomes of egg yolk phospholipids. Lipids 1988, 23, 961–967, doi:10.1007/BF02536344.
[48]
Rensen, P.C.; Schiffelers, R.M.; Versluis, A.J.; Bijsterbosch, M.K.; van Kuijk-Meuwissen, M.E.; van Berkel, T.J. Human recombinant apolipoprotein e-enriched liposomes can mimic low-density lipoproteins as carriers for the site-specific delivery of antitumor agents. Mol. Pharmacol. 1997, 52, 445–455.
[49]
Bisgaier, C.L.; Siebenkas, M.V.; Williams, K.J. Effects of apolipoproteins A-IV and A-I on the uptake of phospholipid liposomes by hepatocytes. J. Biol. Chem. 1989, 264, 862–866.
[50]
Yan, X.; Kuipers, F.; Havekes, L.M.; Havinga, R.; Dontje, B.; Poelstra, K.; Scherphof, G.L.; Kamps, J.A. The role of apolipoprotein e in the elimination of liposomes from blood by hepatocytes in the mouse. Biochem. Biophys. Res. Commun. 2005, 328, 57–62, doi:10.1016/j.bbrc.2004.12.137.
[51]
Akinc, A.; Querbes, W.; De, S.; Qin, J.; Frank-Kamenetsky, M.; Jayaprakash, K.N.; Jayaraman, M.; Rajeev, K.G.; Cantley, W.L.; Dorkin, J.R.; et al. Targeted delivery of rnai therapeutics with endogenous and exogenous ligand-based mechanisms. Mol. Ther. 2010, 18, 1357–1364, doi:10.1038/mt.2010.85.
Cressman, S.; Dobson, I.; Lee, J.B.; Tam, Y.Y.; Cullis, P.R. Synthesis of a labeled RGD-lipid, its incorporation into liposomal nanoparticles, and their trafficking in cultured endothelial cells. Bioconjug. Chem. 2009, 20, 1404–1411, doi:10.1021/bc900041f.
[54]
Allen, T.M.; Sapra, P.; Moase, E.; Moreira, J.; Iden, D. Adventures in targeting. J. Liposome Res. 2002, 12, 5–12, doi:10.1081/LPR-120004771.
[55]
Di Paolo, D.; Ambrogio, C.; Pastorino, F.; Brignole, C.; Martinengo, C.; Carosio, R.; Loi, M.; Pagnan, G.; Emionite, L.; Cilli, M.; et al. Selective therapeutic targeting of the anaplastic lymphoma kinase with liposomal sirna induces apoptosis and inhibits angiogenesis in neuroblastoma. Mol. Ther. 2011, 19, 2201–2212, doi:10.1038/mt.2011.142.
[56]
Li, S.D.; Huang, L. Targeted delivery of antisense oligodeoxynucleotide and small interference RNA into lung cancer cells. Mol. Pharm. 2006, 3, 579–588, doi:10.1021/mp060039w.
[57]
Tam, Y.Y.C.; Chen, S.; Zaifman, J.; Tam, Y.K.; Lin, P.J.C.; Ansell, S.; Roberge, M.; Ciufolini, M.A.; Cullis, P.R. Small molecule ligands for enhanced intracellular delivery of lipid nanoparticle formulations of siRNA. Nanomed. Nanotechnol. Biol. Med. 2013, 9, 665–674, doi:10.1016/j.nano.2012.11.006.
[58]
Li, S.D.; Chono, S.; Huang, L. Efficient oncogene silencing and metastasis inhibition via systemic delivery of siRNA. Mol. Ther. 2008, 16, 942–946, doi:10.1038/mt.2008.51.
[59]
Chen, Y.; Sen, J.; Bathula, S.R.; Yang, Q.; Fittipaldi, R.; Huang, L. Novel cationic lipid that delivers siRNA and enhances therapeutic effect in lung cancer cells. Mol. Pharm. 2009, 6, 696–705, doi:10.1021/mp800136v.
[60]
Cabral, H.; Matsumoto, Y.; Mizuno, K.; Chen, Q.; Murakami, M.; Kimura, M.; Terada, Y.; Kano, M.R.; Miyazono, K.; Uesaka, M.; et al. Accumulation of sub-100 nm polymeric micelles in poorly permeable tumours depends on size. Nat. Nanotechnol. 2011, 6, 815–823, doi:10.1038/nnano.2011.166.
[61]
Huo, S.; Ma, H.; Huang, K.; Liu, J.; Wei, T.; Jin, S.; Zhang, J.; He, S.; Liang, X.J. Superior penetration and retention behavior of 50 nm gold nanoparticles in tumors. Cancer Res. 2013, 73, 319–330, doi:10.1158/0008-5472.CAN-12-2071.
