Enhanced Therapeutic Efficacy of Doxorubicin for Breast Cancer Using Chitosan Oligosaccharide-Modified Halloysite Nanotubes

Halloysite nanotubes (HNTs) are natural aluminosilicates with unique hollow lumen structure, also having high specific area, good biocompatibility, nontoxicity, and low price. Here, we designed a chitosan oligosaccharide-grafted HNTs (HNTs-g-COS) as a doxorubicin (DOX) carrier for treating breast cancer both in vitro and in-vivo. The structure of HNTs-g-COS was first characterized by various methods. HNTs-g-COS showed positively charged surface and improved hemocompatibility. DOX-loaded HNTs-g-COS (DOX@HNTs-g-COS) released in cell lysate in a controlled manner. The IC50 value of DOX@HNT5-g-COS toward MCF-7 cells was 1.17 mu g mL(-1), while it was 2.43 mu g mL(-1) for free DOX. DOX@HNTs-g-COS increased the apoptosis effects of MCF-7 cells as shown in flow cytometry results. Also, reactive oxygen species of cells induced by DOX@HNTs-g-COS were drug-dose-dependent. DOX@HNTs-g-COS could enter the MCF-7 cells and induce mitochondrial damage as well as attack the nuclei. The in vivo antitumor effect of DOX@HNTs-g-COS was investigated in 4T1-bearing mice. The tumor-inhibition ratio of DOX@HNTs-g-COS was 83.5%, while it was 46.1% for free DOX. All mice treated with DOX@HNTs-g-COS survived over 60 days,. DOX@HNT5-g-COS showed fewer ruptured cardiomyocytes and no obvious systemic toxicity. Therefore, the rational designed HNTs nanocarrier for chemotherapy drug showed promising applications in tumor treatment.