In vitro and in vivo suppression of hepatocellular carcinoma growth by chitosan nanoparticles

Chitosan nanoparticles (CNP), a kind of widely used drug carrier, have shown potent cytotoxic effects on various tumour cell lines in vitro and in vivo. This study sought to evaluate the antitumour effect of CNP on growth of human hepatocellular carcinoma (BEL7402) and the possible mechanisms involved. Cells were grown in the absence and presence of various concentrations of CNP with mean particle size of about 40 nm. Cell viability, ultrastructural changes, surface charge, mitochondrial membrane potential, reactive oxygen species (ROS) generation, lipid peroxidation, DNA fragmentation and fatty acid composition were analysed by MTT assay, electron microscopy, zetasizer analysis, flow cytometry, spectrophotometric thiobarbituric (TBA) assays, DNA agarose gel electrophoresis and GC/MS respectively. For in vivo experiments, male BABL/c nude mice were implanted with BEL7402 cells subcutaneously to establish human hepatoma model. Chitosan, saline, and CNP with different mean particle size (40, 70 and 100 nm) were administrated by oral administration (1 mg/kg body weight). Tumour and body weight were measured, morphologic changes of tumour and liver tissues were studied under electron microscope. in vitro, CNP exhibited high antitumour activities with an IC50 value of 15.01 mu g/ml, 6.19 mu g/ml and 0.94 mu g/ml after treatment for 24 h, 48 h and 72 h respectively. CNP could induce cell necrosis observed by electron microscope and DNA fragmentation. The antitumour mechanism was mediated by neutralisation of cell surface charge, decrease of mitochondrial membrane potential and induction of lipid peroxidation. The tumour growth inhibitory rates on BEL7402 cells in nude mice treated with chitosan and CNP with different mean particle size (40, 70 and 100 nm) were 24.07%, 61.69%, 58.98% and 34.91% respectively. Typical necrotic morphological changes of tumour tissues and. no liver abnormalities were found under electron microscope. In this paper, results show a strong antitumour effect of CNP on human hepatoma cell line BEL7402 in vitro and in vivo. These findings suggest that CNP could be a kind of promising agent for further evaluations in the treatment of hepatocellular carcinoma. (c) 2006 Elsevier Ltd. All rights reserved.