The anti-GPC1 antibody AT101 as effective targeting agent for chemotherapeutic-loaded chitosan nanobubbles in the treatment of pancreatic adenocarcinoma.

Recently, we developed AT101, an IgM-class mouse monoclonal antibody directed against glypican-1 (GPC1), a proteoglycan considered as useful target for pancreatic adenocarcinoma (PDAC) treatment being specifically and highly expressed on PDAC cell surface. Here, we proposed AT101 as targeting agent to effectively deliver chitosan nanobubbles (NBs) for PDAC treatment. Different chitosan NB formulations were prepared with or without AT101 conjugation and doxorubicin loading. In PDAC-like BXPC3 cells, unloaded chitosan NBs showed high biocompatibility whereas they showed in-vitro cytotoxic effect once loaded with doxorubicin. In-vivo experiments, in PDAC xenograft model, showed that AT101 is able to target GPC1 when conjugated to chitosan NBs, thus increasing their specific delivery to GPC1-expressing cells of BXPC3 tumor, as compared to chitosan NBs not conjugated to AT101 (p = 0.0043 at 24 h). In-vivo experiments in the same model using chitosan NBs loaded with doxorubicin and conjugated or not with AT101 highlighted the ability of the 2 formulations to slow tumor growth and increase mouse survival compared to free doxorubicin (p = 0.0053 and p = 0.0001, respectively). Conjugation with AT101 further reduced tumor growth and increased survival of treated mice (p = 0.0059). Both chitosan NBs loaded with doxorubicin were able to reduce free doxorubicin toxicity effects. Ex-vivo RNA-seq analysis of extracted BXPC3 tumor masses revealed that AT101 conjugation of chitosan NBs was mainly associated with enhanced xenobiotic metabolism of tumor cells and increased leukocyte migration and proliferation in the tumor microenvironment. In conclusion, the anti-GPC1 AT101 antibody can be used as targeting agent for chemotherapeutic-loaded chitosan NBs for PDAC treatment.