In vivo evaluation of cetuximab-conjugated poly(γ-glutamic acid)-docetaxel nanomedicines in EGFR-overexpressing gastric cancer xenografts

Epidermal growth factor receptor (EGFR), upregulated in gastric cancer patients, is an oncogene of interest in the development of targeted cancer nanomedicines. This study demonstrates in silico modeling of monoclonal antibody cetuximab (CET MAb)-conjugated docetaxel (DOCT)-loaded poly(γ-glutamic acid) (γ-PGA) nanoparticles (Nps) and evaluates the in vitro/in vivo effects on EGFR-overexpressing gastric cancer cells (MKN-28). Nontargeted DOCT-γ-PGA Nps (NT Nps: 110±40 nm) and targeted CET MAb-DOCT-γ-PGA Nps (T Nps: 200±20 nm) were prepared using ionic gelation followed by 1-Ethyl-3-(3-dimethyl aminopropyl)carbodiimide-N-Hydoxysuccinimide (EDC-NSH) chemistry. Increased uptake correlated with enhanced cytotoxicity induced by targeted Nps to EGFR +ve MKN-28 compared with nontargeted Nps as evident from MTT and flow cytometric assays. Nanoformulated DOCT showed a superior pharmacokinetic profile to that of free DOCT in Swiss albino mice, indicating the possibility of improved therapeutic effect in the disease model. Qualitative in vivo imaging showed early and enhanced tumor targeted accumulation of CET MAb-DOCT-γ-PGA Nps in EGFR +ve MKN-28-based gastric cancer xenograft, which exhibited efficient arrest of tumor growth compared with nontargeted Nps and free DOCT. Thus, actively targeted CET MAb-DOCT-γ-PGA Nps could be developed as a substitute to conventional nonspecific chemotherapy, and hence could become a feasible strategy for cancer therapy for EGFR-overexpressing gastric tumors.