Comparison of efficacy of antisense oligomers directed toward tnf-α in helper t and macrophage cell lines

The authors investigated the use of antisense oligomers specific for TNF-α (AS-2) and nonsense control oligomers (NS) in T cells (HT2) and macrophages (RAW264.7), comparing three distinct chemical formulations. Phosphorothioate antisense (S-AS) caused sequence-specific inhibition of TNF-α production by activated HT2s (0.5 μM S-AS 2 vs S-NS: 31.4±1.2%, 4.2±3.2% inhibition, respectively). In contrast, S-AS were ineffective in RAW264.7, despite greater uptake as measured with fluorescent S-oligonucleotides. Furthermore, differences in efficacy of S-AS (HT2>RAW) were not attributable to differences in the pinocytic (HT2=RAW) or adsorptive endocytic (RAW>HT2) pathways implicated in oligonucleotide uptake, suggesting an important role for intracellular events after antisense uptake. Morpholino oligomers (M-AS), in contrast, were more effective in RAW264.7 than in HT2 (32.6±2.6% vs 12.3±0.5% inhibition), consistent with uptake experiments using fluorescent M-oligomers. Phosphodiester oligonucleotides were ineffective in both cell types. It was concluded that antisense efficacy in leukocytes varies according to type of oligomer, cell target and intracellular processing event(s).