Stabilized Plasmid–Lipid Particles: Pharmacokinetics and Plasmid Delivery to Distal Tumors following Intravenous Injection

Abstract

A previous study has shown that plasmid DNA can be encapsulated in lipid particles (SPLP, "stabilized plasmid lipid particles") of approximately 70 nm diameter composed of 1,2-dioleoyl-3-phosphatidyl-ethanolamine (DOPE), the cationic lipid N,N-dioleoyl-N,N-dimethylammonium chloride (DODAC) and poly(ethylene glycol) conjugated to ceramide (PEG-Cer) using a detergent dialysis process (Wheeler et al. (1999) Gene Therapy 6, 271-281). In this work we evaluated the potential of these SPLPs as systemic gene therapy vectors, determining their pharmacokinetics and the biodistribution of the plasmid and lipid components. It is shown that the blood clearance and the biodistribution of the SPLPs can be modulated by varying the acyl chain length of the ceramide group used as lipid anchor for the PEG polymer. Circulation lifetimes observed for SPLPs with PEG-CerC14 and PEG-CerC20 were t(1/2) = approximately 1 and approximately 10 h, respectively. The SPLPs are stable while circulating in the blood and the encapsulated DNA is fully protected from degradation by serum nucleases. The accelerated clearance of SPLPs with PEG-CerC14 is accompanied by increased accumulation in liver and spleen as compared to PEG-CerC20 SPLPs. Delivery of intact plasmid to liver and spleen was detected. Significant accumulation (approximately 10% of injected dose) of the long circulating SPLPs with PEG-CerC20 in a distal tumor (Lewis lung tumor in the mouse flank) was observed following i.v. application and delivery of intact plasmid to tumor tissue at approximately 6% injected dose/g tissue is demonstrated.

A Scalable, Extrusion-Free Method for Efficient Liposomal Encapsulation of Plasmid DNA

“…The cationic lipids dioleyldimethylammonium chloride (DODAC) and 1-O-[2Ј-(-methoxypolyethyleneglycol)2000]-2-N-arachidoylsphingosine (PEG-CerC 20 ) were synthesized as described previously (11,12). The cationic lipid 1,2-dioleyloxy-N,N-dimethylaminopropane (DODMA; Fig.…”

In vitro and in vivo effects of polyethylene glycol (PEG)-modified lipid in DOTAP/cholesterol-mediated gene transfection

“…6 We recently reported the successful use of DOTAP/chol lipoplexes for delivery of suicide gene therapy by intratumoral injection. 16 The rapid clearance from the system of intravenously injected DOTAP/chol-based lipoplexes have been reported, 13,42 and since our gene therapy strategy is aimed at the systemic treatment of subcutaneous xenograft tumors 14 and eventually disseminated SCLC, in this study we sought to stabilize and increase the circulation time of DOTAP/ chol-based lipoplexes that have been modified with different amounts of PEG-lipid, ie, without abolishing the eminent ability to transfect cells. 43,44 Several other works have reported the effect of PEGylation of lipoplexes made from DOTAP or other cationic lipid and with DOPE as the helper lipid, 25,26,[45][46][47] and we discuss these in relation to our findings with PEGylation of DOTAP/chol-based lipoplexes further below.…”

Development of Gene Vectors for Pinpoint Targeting to Human Hepatocytes by Cationically Modified Polymer Complexes

“…Moreover, in vivo the expression of sFlt-1 in the group of sFlt-1/polyMDN administration was as low as in the control group and it has been thought that hepatoma specificity was acquired not by passive targeting but by active targeting for the HBs antigen. Aggregation can be prevented by modifying the surface of the complex with hydrophilic compounds such as polyethylene glycol [29,30] . However, since it shields the cationic charge of the complex, which is the driving force for interaction with target cells, a surface ligand is required for efficient cellular uptake of such complexes.…”