Targeted delivery of doxorubicin to HER2 positive tumor models

Abstract

Background

Exosomes are natural nanovesicles with unique characteristics, such as long circulating half-life, the intrinsic ability to target tissues, biocompatibility, and minimal or no inherent systemic toxicity. Mesenchymal stem cells produce large amounts of exosomes with regenerative properties and more stability in human plasma. TUBO breast cancer cell lines overexpress rat HER2/neu protein.

Methods

Targeted exosomes were isolated from transduced bone marrow mesenchymal stem cells. Doxorubicin was encapsulated into exosomes by electroporation. Flow cytometry was used to assess the attachment of exosomes to the target cells. The in vitro cytotoxicity effect of targeted doxorubicin-loaded exosomes on TUBO cells was determined using MTT assay. Selective delivery of doxorubicin to tumor tissues was analyzed by measuring the auto-fluorescence of doxorubicin by in vivo imaging system. Moreover, tumor growth inhibition and body weight were monitored following injection of free doxorubicin, and targeted and untargeted doxorubicin-loaded exosomes in a TUBO breast cancer model. Finally, mouse tissues were examined for the presence of intrinsic fluorescence of doxorubicin.

Results

Flow cytometry results revealed significant differences in binding of targeted exosomes to HER2-positive (46.05%) and HER2-negative (13.9%) cells. The results of MTT assay showed that cytotoxicity of targeted doxorubicin-loaded exosomes was higher than free doxorubicin at 72 hours. Selective distribution of targeted doxorubicin-loaded exosomes in the target tissues of the murine breast cancer model suggested specific delivery of doxorubicin by targeted exosomes, rather than untargeted exosomes. Free doxorubicin and untargeted doxorubicin-loaded exosomes showed insignificant effects, whereas targeted doxorubicin-loaded exosomes reduced the tumor growth rate.

Conclusion

Herein, we report efficient delivery of targeted doxorubicin-loaded exosomes in vitro, corroborated with a significant reduction of murine breast cancer model tumor growth rate.

Keywords:

• exosome
• breast cancer
• TUBO
• targeted therapy
• drug delivery

View correction statement:

Targeted Delivery Of Doxorubicin To HER2 Positive Tumor Models [Corrigendum]

Acknowledgments

The authors wish to thank Tarbiat Modares University for partially funding the project. This study is a part of the PhD thesis of Hosna Gomari, Tarbiat Modares University, Tehran, Iran.

Abbreviations list

DOX, doxorubicin; exo-dox, doxorubicin-loaded exosome; ECL Western blotting, enhanced chemi-luminescence; EPR, Enhanced permeability and retention; LAMP, lysosome associated membrane protein; HER2, human epidermal growth factor receptor 2; DARPins, designed ankyrin repeat proteins; DMSO, dimethyl sulfoxide; MTT, 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Brom.

Ethical approval

All experiments in this research were done in accordance with the guidelines of the Declaration of Helsinki (1975) and The Society for Neuroscience Animal Care (1998). The guidelines used were approved for implementation by the Medical Ethics Committee, Faculty of Medical Sciences, Tarbiat Modares University, on April 17, 2006. In addition this study, including the animal experiments and use of the TUBO cell lines, was approved by Medical Ethics Committee, Faculty of Medical Sciences, Tarbiat Modares University, on April 28, 2017; approval reference number: IR.TMU.TEC.1395.5.

Disclosure

The authors report no conflicts of interest in this work.