Recent Advances in pH-Sensitive Clay Nanomaterials for Enhanced Immunotherapy of Solid Tumors

Abstract

Tumor microenvironment is a formidable barrier complicated with physicochemical malice to the immune system, limiting the clinical efficacy of immunotherapy, particularly CAR-T in solid tumor management. Various strategies have been proposed and examined to enhance the immunotherapy, while the aberrant and hostile physicochemical microenvironment (such as low pH, hypoxia, high ROS/RNS and deficient nutrient ions) is always a key and general challenge that has to be addressed ahead in order to improve the efficacy of CAR-T and immune checkpoint blockage for solid tumor treatment. Fortunately, recent investigations demonstrate that some clay nanomaterials are able to correct the aberrant pH and O2 levels in the tumor microenvironment and recruit more anti-tumor immune cells into tumor tissues, breaking the immunosuppressive barrier and inhibiting tumor growth in vivo. This minireview paper briefly summarizes the timely progresses in restoring the physicochemical homeostasis in tumor tissues to convert the ‘cold’ to ‘hot’ immune microenvironment for enhanced immunotherapy of solid tumors and further provide my personal perspectives for the future research.