Targeted Imaging And Treatment Of Tumor Based On Modified Protein Nanomaterials

Objective With the development of biomedical technology,more and more nanomaterials have been used in targeting imaging and treatment for cancer.Among them,nanomaterials have always been a research hotspot as targeting drug carriers.Ferritin as a nanopartical is a promising targeted drug carrier due to the following unique properties: high biocompatibility,easy to modify and naturally occurred as nanocage with inner cavity.Meanwhile,tumor-specific antibody,such as Herceptin,has proved its value in clinic.Therefore,combination of ferritin with certain tumor-specific antibody would exert both of their advantages.In this study,Heavy chain ferritin(HFn)was coupled with anti-HER2 antibody to form HFn/anti-HER2 conjugate.In vivo characterization was then performed.Tumor targeting ability and bio-distribution were carefully examined.This work would provide basis for ferritin-based targeted therapy.Methods HFn was first expressed and purified in E.coli and anti-Human Epidermal Growth Factor Receptor-2 antibody(anti-HER2)was selected as model antibody.HFn was then coupled to anti-HER2 via a bifunctional cross-linker MAL-PEG-NHS to form a complext(HFn/anti-HER2).The complex was separated and purified with size exclusion gel filtration chromatography and characterized by DLS and transmission electron microscopy.For evaluation,the distribution of the complex in breast cancer cells with different HER2 expression was observed in vitro;HER2 positive breast cancer-bearing mice was first constructed and characterized with bioluminescence.Tumor targeting ability and bio-distribution of the HFn/anti-HER2 complex were validated in the mice model.Results HFn was successfully expression by E.coli and confirmed by gel electrophoresis.HFn was coupled with anti-HER2 and purified by size exclusion chromatography.The complex(HFn/anti-HER2)showed an increased particle diameter of 16.88±0.49 nm compared with that of 7.11±0.1 nm for HFn.Stability of the complex was also conformed as uniformed size after storage of over one month in PBS.Further in vitro and in vivo study showed that the complex had better tumor targeting ability.Conclusion In this study a heavy chain ferritin and antibody complex was constructed.The tumor targeting ability of heavy chain ferritin was enhanced due to coupling with antibody.The heavy chain ferritin is a potential cancer drug carrier.This study provided a possible strategy to enhance the tumor targeting ability of ferritin which may further increase the utility of ferritin in cancer therapy.