Delivery of antisense oligonucleotides to PC12 cells

Optimal experimental conditions for the delivery of phosphodiester or phosphorothioate antisense oligonucleotides (P-ASO/S-ASO) to PC12 cells were determined. Fluorescently labeled P-ASO or S-ASO were transfected to PC12 cells and the uptake of antisense, free or entrapped in liposomes, was monitored by confocal and fluorescent microscopy. Efficient delivery of fluorescently labeled ASO with low rates of cell death was obtained when PC12 cells were transfected with liposomes in Opti-MEM medium supplemented with sera, compared with control experiments where nonliposomal ASO were transfected to PC12 cells in sera-free media. Compared with P-ASO, the application of S-ASO for antisense studies in PC12 cells is more suitable due to the lower concentration required for an efficient antisense uptake and its higher intracellular stability.