Enzyme responsiveness enhances the specificity and effectiveness of nanoparticles for the treatment of B16F10 melanoma

The clinical treatment of melanoma continues to present many challenges including poor prognosis because neither monotherapy nor combination therapies have shown maximal treatment efficacy. In this study, an enzyme-responsive nanoparticle was designed for tumor subtypes with the high expression of heparanase-1, since highly metastatic tumors such as melanoma generally express significant levels of heparanase-1. PTX-DOTAP@alloferon-1-heparin/protamine, an enzyme-responsive nanoparticle, has a particle size of 106.1 ± 1.113 nm and a ζ-potential of -45.1 ± 0.455 mV, which enables enrichment in the tumor site by passive targeting. Subsequently, heparanase-1, which is highly expressed in the extracellular matrix, rapidly recognizes and degrades heparin in the outer layer of the nanoparticle and releases encapsulated alloferon-1 by ion diffusion to activate inhibited NK cells in the tumor microenvironment. The size of the smart nanoparticle will eventually decrease to 59.30 ± 0.783 nm and the ζ-potential will reverse to 25.4 ± 0.257 mV, which is beneficial for deep penetration and tumor cell uptake (due to the high negative charge on the tumor cell surface) of PTX-DOTAP cores. Paclitaxel is released in the cytoplasm, and the tumor cells are arrested in the G2/M phase. The nanoparticle characterization experiment demonstrated that in vivo drug delivery could be completed. In subsequent cell and animal experiments, the experimental data demonstrated the efficient therapeutic effects of the nanoparticle. This study provides an excellent template nanoparticle for the treatment of highly metastatic tumors to enhance future prognosis.