We report the first nanoformulation of
Hyaluronidase (Hyal) and its enhanced adjuvant effect over the free
enzyme.
Hyaluronic acid (HA) degrading
enzyme Hyal was immobilized on 250 nm
silica nanoparticles (SiNP) maintaining specific activity of the
enzyme via the layer-by-layer self-assembly technique. This process was characterized by dynamic light scattering (DLS), zeta potential, infrared and UV-Vis spectroscopy, transmission electron microscopy (TEM) and enzymatic activity measurements. The nanoparticles were tested in vivo as adjuvants of
carboplatin (CP), peritumorally injected in A375 human
melanoma bearing mice and compared with the non-
immobilized enzyme, on the basis of equal enzymatic activity.
Alcian Blue staining of A375
tumors indicated large overexpression of
hyaluronan. At the end of the experiment,
tumor volume reduction with SiNP-immobilized Hyal was significantly enhanced compared to non-immobilized Hyal. Field emission scanning electron microscopy (FE-SEM) images together with energy dispersive X-ray spectroscopy (EDS) spectra confirmed the presence of SiNP on the
tumor. We mean a proof of concept: this extracellular matrix (ECM) degrading
enzyme, immobilized on SiNP, is a more effective local adjuvant of
cancer drugs than the non-
immobilized enzyme. This could prove useful in future
therapies using other or a combination of ECM degrading
enzymes.