Efficient delivery of a Bcl-2-specific antisense oligodeoxyribonucleotide (G3139) via transferrin receptor-targeted liposomes.
A novel transferrin receptor (TfR)-targeted liposomal formulation was synthesized and evaluated for the delivery of a phosphorothioate antisense oligodeoxyribonucleotide (ODN) (G3139, oblimerson sodium, or Genasense) to Bcl-2 in K562 leukemia cells. Liposomes composed of DC-Chol/egg PC/PEG-DSPE (25:73.5:1.5, mol/mol/mol) were loaded with G3139 with high efficiency (70-80%). To prepare targeted liposomes, transferrin was first coupled to PEG-DSPE and then incorporated into the bilayer by post-insertion. The liposomes had a mean diameter of 100 to 150 nm and exhibited colloidal stability for up to 8 weeks. Uptake of Tf-conjugated G3139-containing liposomes in TfR positive K562 cells was found to be more efficient than that of the non-targeted control formulation and could be blocked by excess free Tf. Treatment with Tf-conjugated liposomes resulted in Bcl-2 protein downregulation in K562 cells that was approximately 2-fold greater than with non-targeted liposomes (p<0.05) and 10-fold greater than with free G3139. Treatment with 2 microM G3139 in Tf-conjugated liposomes resulted in >80% reduction in Bcl-2 transcript. In addition, Tf-conjugated liposomal G3139-sensitized K562 cells to daunorubicin, lowering IC50 from 1.8 microM to 0.18 microM. In conclusion, Tf-conjugated liposomes are effective delivery vehicles for G3139 antisense oligos in TfR positive K562 cells and warrant further investigation as an in vivo oligo delivery vehicle.
Chiu
Shih-Jiuan
SJ
Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA.
Liu
Shujun
S
Perrotti
Danilo
D
Marcucci
Guido
G
Lee
Robert J
RJ
D015153:Blotting, Western; D015536:Down-Regulation; D016503:Drug Delivery Systems / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D020014:K562 Cells; D008024:Ligands; D008081:Liposomes; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D011990:Receptors, Transferrin / Q000378:metabolism*; D013873:Thionucleotides / Q000008:administration & dosage*
D008024:Ligands; D008081:Liposomes; D019253:Proto-Oncogene Proteins c-bcl-2; D011990:Receptors, Transferrin; D013873:Thionucleotides; C408162:oblimersen