Enhanced antiproliferative activity of antibody-functionalized polymeric nanoparticles for targeted delivery of anti-miR-21 to HER2 positive gastric cancer.

MiR-21 is an oncogenic miR frequently elevated in gastric cancer. Overexpression of miR-21 decreases the sensitivity of gastric cancer cells to trastuzumab, which is a humanized monoclonal antibody targeting human epidermal growth factor receptor 2. However, optimization of miRNA or its anti-miRNA oligonucleotides (AMOs) for delivery is a challenge. Receptor-mediated endocytosis plays a crucial role in the delivery of biotherapeutics including AMOs. This study is a continuation of our earlier findings involving poly(ε-caprolactone) (PCL)-poly (ethylene glycol) (PEG) nanoparticles (PEG-PCL NPs), which were coated with trastuzumab to target gastric cancer cells with HER2 receptor over-expression using anti-miRNA-21 antisense oligonucleotides (AMO-21). The antibody conjugates (HER-PEG-PCL NPs) act against target cells via antibody-dependent mechanisms and also based on encapsutalated AMO-21. X-ray photoelectron spectroscopy validated the presence of trastuzumab on NP surface. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a stable antibody expression. The cell line specificity, cellular uptake, AMO-21 delivery, and cytotoxicity of the HER-PEG-PCL NPs were investigated. We found that the antibody conjugates significantly enhanced the cellular uptake of NPs. The HER-PEG-PCL NPs effectively suppressed the target miRNA expression in gastric cancer cells, which further up-regulated phosphatase and tensin homolog (PTEN). As a result, the sensitivity of HER2-expressing gastric cancer cells to trastuzumab was enhanced. The approach enhances the targeting by trastuzumab as well as antibody-dependent cellular cytotoxicity of immune effector cells. The antitumor effects of AMO-21-HER-PEG-PCL NPs were compared with trastuzumab in xenograft gastric cancer mice. The results provide insight into the biological and clinical potential of targeted AMO-21 delivery using modified trastuzumab for gastric cancer treatment.

Efficacy of decitabine-loaded gelatinases-stimuli nanoparticles in overcoming cancer drug resistance is mediated via its enhanced demethylating activity to transcription factor AP-2 epsilon.

Hypermethylation of the transcription factor AP-2 epsilon (TFAP2E) gene affects 5-fluorouridine (5-FU) resistance in gastric cancer (GC) patients. The epigenetic inhibitor 5-Aza-2'-deoxycytidine (DAC), which reverses DNA methylation by targeting DNA methyltransferases (DNMTs), has potential to sensitize GC to 5-FU. Nevertheless, DNA demethylation only DAC transiently occurs since DAC is unstable in aqueous solutions, which limits its potential. Here we developed intelligent nanoparticles (NPs) comprising gelatinase with polyethylene glycol (PEG) and poly-ε-caprolactone) (PCL) to specifically deliver DAC (DAC-TNPs) to tumors. DAC-carrying PEG-PCL NPs (DAC-NPs) lacking gelatinase features served as controls. 72 hours after administration of DAC-TNPs or DAC-NPs, 5-FU was sequentially applied to GC cells and human GC xenografts in nude mice. Both in vitro and in vivo evaluations demonstrated that the combination treatment of DAC-TNPs and 5-FU greatly improved tumor suppression in GC cells and mouse xenograft models with hypermethylation TFAP2E (MKN45 cells). We thus propose that the sequential administration of DAC-TNPs and 5-FU could be significant in the development of novel targeted therapies.