Leveraging mesoporous silica nanomaterial for optimal immunotherapeutics against cancer.

Cancer represents a significant cause of morbidity and mortality. Definitive chemotherapy, surgery and radiotherapy treatment have not improved the "5-year survival period" and have shown recurrence. Currently, cancer immunotherapy is reported to be a promising therapeutic modality that aims to potentiate immune response against cancer by employing immune checkpoint inhibitors, cancer vaccines and immunomodulators. Inhibition of immune checkpoints such as PD-1/PDL1, CTLA and TIM molecules using monoclonal antibodies, ligands or both are proven to be the most successful anticancer immunotherapy. But the application of immunotherapy involves critical challenges such as non-responsiveness and systemic toxicity due to the administration of high dose. To mitigate the above challenges, nanomaterial-based delivery and therapy have been adopted to inhibit the immune checkpoints and induce an anticancer immune response. Specifically, mesoporous silica-based materials for cancer therapy are shown to be versatile materials for the above purpose. Mesoporous silica nanoparticle (MSN) based cancer immunotherapy overcomes numerous challenges and offers novel strategies for improving conventional immunotherapies. MSN has a high surface area, porosity and biocompatibility; it also has natural immune-adjuvant properties, which have been reported to be the best candidate material for immunotherapeutic delivery. This review will focus on the use of MSN as carriers for delivering immune checkpoint inhibitors and their efficacy in cancer combination therapy.