Dual-pore protocells with multitasking capacities for simultaneous delivery of therapeutic enzymes and drugs in macrophage depletion therapy.

Abstract

Macrophages are usually present in solid tumors where they participate in tumor progression, angiogenesis, immunosuppression and metastasis. The design of nanocarriers capable of delivering therapeutic agents to specific cell populations has received considerable attention in the last decades. However, the capacity of many of these nanosystems to deliver multiple therapeutic agents with very different chemical properties is more limited. Herein, a novel multitasking nanoplatform capable of delivering large macromolecules and cytotoxic drugs to macrophages is presented. This novel nanosystem has exhibited excellent skills in performing simultaneous tasks, macrophage depletion and glucose starvation, maintaining the oxygen levels in the tissue. This nanodevice is composed of a dual-pore mesoporous silica core with the capacity to house small cytotoxic drugs, such as doxorubicin or zoledronic acid, and large macromolecules, such as glucose oxidase. The external surface of the silica core was coated with a lipid bilayer to avoid the premature release of the housed drugs. Finally, polymeric nanocapsules loaded with catalase were covalently anchored on the outer lipid bilayer, and carboxy-mannose was attached to the exposed side of the nanocapsules to provide selectivity to the macrophages. These nanoassemblies were able to transport enzymes (Gox and CAT), maintaining their catalytic activity. Therefore, they could induce glucose starvation, keeping the oxygen levels in the tissue, owing to the tandem enzymatic reaction. The capacity of these nanoassemblies to deliver therapeutic agents to macrophages was evaluated both in static and under flow conditions, showing a rapid capture of the nanoparticles by the macrophages. Once there, the nanoassemblies also exhibited excellent capacity to induce potent macrophage depletion. This strategy can be directly adapted for the treatment of different malignancies due to the modular nature of the nanoplatform, which can be loaded with different therapeutic agent combinations and pave the way for the development of personalized nanomedicines for diverse types of tumors.