Expression of Bcl-2 and Akt-1 has been associated with human cancer. G3139 and RX-0201, targeting Bcl-2 and Akt-1, respectively, are antisense oligonucleotides (ASOs) that have shown limited efficacy in clinical trials. Herein, we report a combination of newly designed ASOs based on these agents and was delivered by tumor cell-targeting lipid nanoparticles (LNPs). A "Gapmer" design strategy was applied to these ASOs with the addition of 2'-O-methyl modifications on the nucleotides at 5' and 3' ends. A dual-channel syringe pump-based system was developed for the synthesis of the LNPs. ASO-LNPs composed of DODMA, egg PC, cholesterol, T7-PEG-DSPE, and PEG-DMG at a molar ratio of 35:39.5:20:0.5:5 and carrying either individual ASOs or co-loaded ASO combinations (Co-ASOs) were synthesized and evaluated in both KB and A549 cancer cells and in an A549 murine xenograft model to determine their antitumor effects and biological activities. The ASO-LNPs exhibited excellent colloidal stability and high ASO encapsulation efficiency with relatively small mean particle sizes and moderately positive zeta potentials. Transferrin receptor-targeting T7-conjugated LNPs showed enhanced cellular uptake compared to nontargeted LNPs. In addition, both T7-conjugated Co-ASOs-LNPs and non-T7-conjugated Co-ASOs-LNPs at a molar ratio of (G3139-GAP to RX-0201-GAP at 1:2) showed efficient downregulation of both Bcl-2 and Akt-1 in both A549 and KB cells. Furthermore, T7-conjugated Co-ASOs-LNPs (Co-ASOs-LNPs) produced superior antitumor activity, prolonged the overall survival time, and demonstrated tumor targeting activity in an A549 xenograft model.
Keywords: T7 peptide; antisense oligonucleotide; cancer; lipid nanoparticles; oligonucleotide combination; synergism.