Cationic lipids enhanced cellular uptake and activity of bcl-2 antisense oligodeoxynucleotide G3139 in HL-60 cells

To explore the effect of cationic lipid 1,3-di-oleoyloxy-2-(6-carboxy-spermyl)-propylamid (DOSPER) on cellular uptake and activity of bcl-2 antisense oligodeoxynucleotide G3139 in HL-60 cells.

The cell-associated mean fluorescence intensity and the percentage of cells with positive staining for Bcl-2 were measured by flow cytometry. The subcellular distribution of fluorescein isothiocyanate (FITC)-labeled G3139 was observed by fluorescence microscope and the bcl-2 mRNA level was detected by reverse transcription polymerase chain reaction (RT-PCR).

(1) DOSPER increased cellular uptake of G3139 into HL-60 cells greatly. When DOSPER/G3139 (microg : microg) was 2 : 1, the uptake of G3139 reached top after treatment for 2 h and increased about 20 times compared with application of G3139 alone. In the presence of DOSPER, G3139 was localized in nucleus and cytosol with a bright spotted fluorescence staining. However, G3139 was localized in cytoplasm with faint fluorescence in the absence of DOSPER. (2) Cell-associated G3139 could be effluxed out of cells. After treated with G3139 in the presence of DOSPER for 4 h, the cell-associated G3139 could be fitted by C(t)=68.2e(-0.60) t+31.8e(-0.02) t (% of initial value), with a half-life of approximately 1.1 h. In the absence of DOSPER, the cell-associated G3139 could be fitted by C(t)=64.8e(-2.27) t+35.2e(-0.04) t, with a half-life of about 18 min. (3) In the presence of DOSPER, G3139 1.0 micromol/L specially reduced bcl-2 mRNA level, and Bcl-2 protein decreased from 97 % +/- 4 % to 70.6 % +/- 2.1 %.

DOSPER enhanced the activity of G3139 and it might be attributed to increase of the cellular uptake and change of the subcellular distribution of G3139.