One of the main reasons why most cancer patients do not
respond
well to chemotherapy is that drugs cannot accumulate in tumors at
an optimal dose, eventually resulting in failure to prevent cancer
cell growth. To improve drug delivery efficiency, we engineered a
highly efficient tumor-targeted and stroma-breaking nanocarrier by
the modification of iron oxide nanoparticles (IONPs) with a tumor-targeting
peptide c(RGDyK) and a hyaluronidase (HAase) on the surface. The yielding
nanocomplex, c(RGDyK)-HAase-IONP, targeted the tumor by binding integrin
αvβ3 and went deeply into the tumors
by the degradation of hyaluronic acid (HA), which was highly expressed
in the tumor extracellular matrix (ECM). Good biostability and a low
pH preferred drug release profile were characterized for c(RGDyK)-HAase-IONP
carrying DOX in vitro. c(RGDyK)-HAase-IONP showed an improved tumor-targeting
(2.5 times higher) effect after intravenous injection in the MC38
tumor-bearing mice model, as determined by whole-body fluorescence
imaging compared to the non-targeted IONPs without HAase. After 5
systemic treatments, c(RGDyK)-HAase-IONP/DOX (5 mg/kg of equivalent
dose of DOX) significantly inhibited MC38 tumor growth (22.1 ±
7.4 times relative to the non-treated group). Elevated apoptosis and
reduced proliferation in the tumor cell were detected in the c(RGDyK)-HAase-IONP/DOX
treated tumors compared to the control groups. Overall, the highly
efficient targeted nanocarrier c(RGDyK)-HAase-IONP demonstrated tremendous
potency for improving drug delivery and tumor therapy efficacy by
targeted degradation of the dense HA barrier in the tumor ECM. We
determined that such a tumor stroma–degrading nanosystem was
capable of reducing tumor recurrence and drug resistance and could
ultimately improve clinical tumor treatment responses.