Multiple systemic expression of human interferon-β in mice can be achieved upon repeated administration of optimized pcTG90-lipoplex

Abstract

The possibility of achieving multiple systemic expression of human interferon-␤ in mice upon repeated intravenous administration of cationic liposome-DNA complex (lipoplex) was investigated. Lipoplexes containing the pentammonio lipid pcTG90 were first optimized by selecting the most efficient ratio of pcTG90 to phosphatidylethanolamine (DOPE) and the N/P ratio of cationic lipid nitrogen to DNA phosphate. Highest levels and reproducibility of gene expression were obtained using pcTG90/DOPE (1:2) liposomes complexed with the IFNB1 gene containing plasmid pTG14169 at a N/P ratio of 10. Following lipoplex administration, an early but transient human interferon-␤ expression in serum was observed. Importantly, repeated systemic

Immunostimulatory activity of cationic-lipid-nucleic-acid complexes against cancer

“…Intravenous administration of CLNACs in mice may cause an immune response that prevents a subsequent administration of these complexes into mice after a relatively short interval (Meyer et al 2000). Repeated systemic gene expression could be achieved by readministration with a minimal time interval of 14 days between two injections.…”

Repeated intrathecal administration of plasmid DNA complexed with polyethylene glycol-grafted polyethylenimine led to prolonged transgene expression in the spinal cord

“…In the case of cationic lipidic vectors, repetitive intravenous administrations are not effective at frequent intervals. 7,8,22 Apoptosis and inactivation of gene expression triggered by interferon-g and tumor necrosis factor-a, which may be induced by direct immunostimulatory effects of unmethylated CpG sequences in plasmid DNA, have been identified as two causes, among others, for this ineffectiveness. 7,22 The same mechanism may be in force when PEI is used as a delivery system for plasmid DNA and be responsible for observed apoptotic cell death in the spinal cord after intrathecal injection of PEI/DNA complexes.…”

“…Several laboratories have addressed this issue in peripheral organs using repeated intravenous or intratracheal administration. [7][8][9] Unique attributes of the CNS, includ-ing limited access because of the skull and the bloodbrain barrier and high vulnerability to injury, pose severe obstacles to safe repetitive gene delivery. The commonly used gene delivery techniques, like direct injection into the brain and spinal cord tissues, are highly invasive and not practical in a repeat injection scheme.…”

Stabilization of Plasmid DNA and Lipid-Based Therapeutics as Dehydrated Formulations

“…Furthermore, aqueous suspensions of nonviral vectors are known to aggregate over time [46,68]. For instance, the high tendency of lipid/DNA complexes to aggregate in aqueous suspensions has prompted the use of these liposomal formulations within a short period of time after preparation [69,70], and aggregation is further exacerbated in the highly concentrated suspensions prepared for clinical studies [71]. Additional stresses such as agitation and freeze-thawing can also contribute to lipid/DNA complex aggregation [72].…”