Abstract
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 μM 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 μM to 0.18 μM. 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.
Original language | English |
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Pages (from-to) | 199-207 |
Number of pages | 9 |
Journal | Journal of Controlled Release |
Volume | 112 |
Issue number | 2 |
DOIs | |
Publication status | Published - May 15 2006 |
Keywords
- Antisense oligonucleotide
- Bcl-2
- Leukemia
- Liposomes
- Transferrin
ASJC Scopus subject areas
- Pharmaceutical Science