Purpose: Bcl-2 is an anti-apoptotic gene that is frequently overexpressed in human cancers. G3139 is an antisense oligonucleotide against bcl-2 that has shown limited efficacy in clinical trials. Here, we report the synthesis of a new antisense oligonucleotide containing additional chemical modifications and its delivery using nanoparticles.
Methods: An oligonucleotide G3139-GAP was synthesized, which has 2'-O-methyl nucleotides at the 5' and 3' ends based on a "gapmer" design. Furthermore, G3139-GAP was incorporated into lipid nanoparticles (LNPs) composed of DOTAP/egg PC/cholesterol/Tween 80. The LNP-loaded G3139-GAP was evaluated in A549 lung cancer cells both in vitro and in a murine xenograft model for biological activity and therapeutic efficacy.
Results: The LNPs showed excellent colloidal and serum stability, and high encapsulation efficiency for G3139-GAP. They have a mean particle diameter and zeta potential of 134 nm and 9.59 mV, respectively. G3139-GAP-LNPs efficiently downregulated bcl-2 expression in A549 cells, as shown by 40% and 83% reduction in mRNA and protein levels, respectively. Furthermore, G3139-GAP-LNPs were shown to inhibit tumor growth, prolong survival, and downregulate tumor bcl-2 expression in an A549 murine xenograft tumor model. These data indicate that G3139-GAP-LNPs have excellent anti-tumor efficacy and warrant further evaluation.
Keywords: antisense oligonucleotide; bcl-2; cancer; drug delivery; lipid nanoparticles.