Anti-Tumor Immune Response of Folate-Conjugated Chitosan Nanoparticles Containing the IP-10 Gene in Mice with Hepatocellular Carcinoma

Abstract

Immunotherapy is one of the most promising new therapies for hepatocellular carcinoma (HCC) in recent years. In this study, folate-conjugated chitosan nanoparticles (FA-CS-NPs) were loaded with mouse interferon-γ-inducible protein-10 (IP-10) plasmid, which were used for immunotherapy in HCC. H22 tumor-bearing mice were treated with FA-CS-NPs entrapped IP-10 plasmid and targeting efficiency was observed by optical imaging in vivo. Flow cytometry was used to measure the number of myeloid-derived suppressor cells (MDSCs) in the tumor and CD4+CD25+FoxP3+ T-regulatory cells (CD4+CD25+FoxP3+ Tregs) in the spleen. The enzyme-linked immunospot (ELISPOT) assay was used to quantify the number of interferon-γ (IFN-γ)-positive cells. IP-10 expression, tumor vessel density, cell proliferation and apoptosis were evaluated by immunohistochemistry. It was shown that FA-CS-NPs entrapped IP-10 plasmid displayed anti-tumor activity with inhibition of tumor growth and prolonging the survival time in H22 tumor-bearing mice. Treatment of H22 tumor-bearing mice with FA-CS-NPs entrapped IP-10 plasmid inhibited angiogenesis and promoted IP-10 expression and induced apoptosis in the tumor. FA-CS-NPs entrapped IP-10 plasmid-treated mice also had a lower proportion of Tregs in the spleen, a higher proportion of MDSCs in the tumor and higher number of IFN-γ-positive cells in the spleen compared with the mice from the other experimental groups. These data suggested that the gene delivery system of folate-conjugated chitosan nanoparticle loaded with IP-10 plasmid may be a promising strategy for immunotherapy of HCC.