A long-circulating formulation of pH-sensitive liposomes (PSLs) with antibodies against epidermal growth factor receptor (EGFR) attached was designed, expecting an increase in binding and delivery of liposomes to the target cells including non-small cell lung cancer (NSCLC) cells. Physicochemical properties of the PSLs were measured by SEM and DLS. Leakage of a self-quenching fluorescent probe, calcein, from the liposome was studied for the evaluation of pH-sensitivity. Encapsulation efficiency of gemcitabine (an anti-cancer drug) in PSLs was about 67%. Average size of liposomes was 88 nm in diameter. The PSL of DOPE/CHEMS (6:4 molar ratio) formulation showed a dramatic pH-sensitivity at/around pH 5.5, whereas non-PSL of DPPC/Chol or PC/CHEMS formulation did not. Anti-proliferation effect of gemcitabine-encapsulating PSLs & Ab-PSLs in A549 cells was 2-fold higher than the free drug, which was further elucidated by the apoptosis of the cells by gemcitabine (∼10% apoptosis for PSL or Ab-PSL formulation vs. ∼1% for free drug or non-PSL formulation) using FACS analysis. These data demonstrate delivery of gemcitabine to tumor cells can be improved by long-circulating PSLs or Ab-PSLs formulations in vitro.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Ahmad, I. and Allen, T. M., Antibody-mediated specific binding and cytotoxicity of liposome-entrapped doxorubicin to lung cancer cells in vitro, Cancer Res., 52, 4817 (1992).
Allen, T. M., Austin, G. A., Chonn, A., Lin, L., and Lee, K. C., Uptake of liposomes by cultured mouse bone marrow macrophages: influence of liposome composition and size, Biochim. Biophys. Acta., 1061, 56–64 (1991).
Allen, T. M., Brandeis, E., Hansen, C. B., Kao, G. Y., and Zalipsky, S., A new strategy for attachment of antibodies to sterically stabilized liposomes resulting in efficient targeting to cancer cells, Biochim. Biophys. Acta., 1237, 99 (1995).
Alving, C. R., Liposomes: Biophysics to Therapeutics. Marcel Dekker, New York, (1987).
Bangham, A. D., Standish, M. M., and Watkins, J. C., Diffusion of univalent ions across the lamellae of swollen phospholipids, J. Mol. Biol., 13, 238–252 (1965).
Bartlett, G. R., Phosphorus assay in column chromatography, J. Biol. Chem., 234, 466–468 (1959).
Bligh, E. G. and Dyer, W. J., A rapid method of total lipid extraction and purification, Can. J. Med. Sci., 37, 911–917 (1959).
Bradford, M. M., A rapid and sensitive method for thequantitation of microgram quantities of protein utilizing the principle of protein-dye binding, Anal. Biochem., 72, 248–254 (1976).
Carlsson, J., Drevin, H., and Axen, R., Protein thiolation and reversible protein-protein conjugation. N-Succinimidyl 3-(2-pyridyldithio)propionate, a new heterobifunctional reagent, Biochem. J., 173, 723 (1978).
Debs, R. J., Heath, T. D., and Papahadjopuolos, D., Targeting of anti-Thy 1.1 monoclonal antibody conjugated liposomes in Thy 1.1 mice after intravenous administration, Biochim. Biophys. Acta., 901, 183 (1987).
Heath, T. D. and Lopez, N. G., 5-Fluoroorotate: a new liposome-dependent cytotoxic agent, FEBS Lett., 187, 73–75 (1985).
Heath, T. D., Montgomery, J. A., Piper, J. R., and Papahadjopuolos, D., Antibody-targeted liposomes: increase in specific toxicity of methotrexate-gamma-aspartate, Proc. Natl. Acad. Sci. USA., 80, 1377 (1983).
Martin, F. J., Heath, T. D., and New, R. R. C., Liposomes: A practical approach, IRL press, Oxford, (1990).
Peschka-Suss, R. and Schubert, R., Liposomes. Oxford University Press, New York, (2003).
Slepushkin, V. A., Simões, S., Dazin, P., Newman, M. S., Guo, L. S., Lima, M. C., and Düzgüneş, N., Sterically stabilized pH-sensitive liposomes. Intracellular delivery of aqueous contents and prolonged circulation in vivo, J. Biol. Chem., 272, 2382–2388 (1997).
Szoka, F. and Papahadjopoulos D., Procedure for preparation of liposomes with large internal aqueous space and high capture by reverse-phase evaporation, Proc. Natl. Acad. Sci. U.S.A., 75, 4194–4198 (1978).
About this article
Cite this article
Kim, MJ., Lee, H.J., Lee, IA. et al. Preparation of pH-sensitive, long-circulating and EGFR-targeted immunoliposomes. Arch. Pharm. Res. 31, 539 (2008). https://doi.org/10.1007/s12272-001-1190-9
- pH-Sensitive liposome (PSLs)