Nanoassembly with self-regulated magnetic thermal therapy and controlled immuno-modulating agent release for improved immune response.

ABSTRACT

Cancer immunotherapy is an emerging cancer therapeutic method by activating the patient's immune system but suffers from low immunogenicity at tumor sites. Fever-like heat is known to modulate an immune-friendly tumor microenvironment. Here, temperature-responsive iron oxide nanoassemblies (IONAs) are developed by crosslinking iron oxide nanoparticles (IONPs) and loaded with JQ1 (JQ1/IONAs), an immuno-modulating agent known to down-regulate PD-L1. In the presence of an alternating magnetic field (AMF), the IONAs demonstrate a much more effective magnetic thermal effect than IONPs and are responsively disassembled to prevent overheating. Compared with IONPs + AMF (∼ 41 °C) and unresponsive nanoassemblies (uIONAs) + AMF (∼ 50 °C), the IONAs + AMF with a temperature heated around 45 °C show a much better immune response and anti-tumor effect. Further combining the mild thermal therapy with controlled release of JQ1, the JQ1/IONAs + AMF completely eradicate the primary tumors and trigger a strong immune effect to inhibit the distant tumor growth as well as prevent tumor recurrence and metastasis. Our JQ1/IONAs not only provide a magnetic thermal agent with effective heating and temperature self-regulation ability but also serve as a heat-triggered JQ1 carrier to spontaneously combine mild magnetic thermal therapy with immune checkpoint blockade therapy.