Surfactin-based nanoparticles loaded with doxorubicin to overcome multidrug resistance in cancers.

Background: Multidrug resistance (MDR) is one of the major obstacles to successful cancer chemotherapy. Developing efficient strategies to reverse MDR remains a major challenge. Surfactin (SUR), a cyclic lipopeptide biosurfactant, has been found to display anticancer activity.

Methods: In this paper, SUR was assembled by solvent-emulsion method to load the anticancer drug doxorubicin (DOX). The cytotoxicity of DOX-loaded SUR nanoparticles (DOX@SUR) against DOX-resistant human breast cancer MCF-7/ADR is measured by MTT assay. The cellular uptake and intracellular retention of DOX@SUR are determined by flow cytometry. The tumor accumulation and anticancer activity of DOX@SUR are evaluated in MCF-7/ADR-bearing nude mice.

Results: DOX@SUR induce stronger cytotoxicity against DOX-resistant human breast cancer MCF-7/ADR cells compared to free DOX. DOX@SUR nanoparticles exhibit enhanced cellular uptake and decreased cellular efflux, which might be associated with reduced P-glycoprotein expression. After internalization into MCF-7/ADR cells by macropinocytosis- and caveolin-mediated endocytosis, DOX@SUR nanoparticles are colocalized with the lysosomes and translocated to the nucleus to exert cytotoxicity. Furthermore, in vivo animal experiment shows that the DOX@ SUR nanoparticles are accumulated more efficiently in tumors than free DOX. Meanwhile, DOX@SUR nanoparticles display stronger tumor inhibition activity and fewer side effects in MCF-7/ADR-bearing nude mice.

Conclusion: This study indicates that SUR-based nanocarrier might present a promising platform to reverse MDR in cancer chemotherapy.