A Cytotoxic T Lymphocyte-Inspiring Microscale System for Cancer Immunotherapy

Adoptive T cell therapy (ACT) is an emerging cancer immunotherapy undergoing clinical evaluation, showing significant promise in the treatment of solid tumors. However, the clinical translation of ACT is hindered by its time-, labor-, and financial-consuming procedures, heterogeneity of cytotoxic T lymphocytes (CTLs), and immunosuppressive tumor microenvironment. Herein, we have developed a bionic cytotoxic T lymphocyte-inspiring microscale system (CTLiMS) composed of mesoporous silica dioxide microspheres containing membrane-disrupting boron clusters (BICs) and proapoptotic monomethyl auristatin E (MMAE) peptides. The BICs were found to disrupt the integrity of cancer cell membranes and enhance the internalization of MMAE, effectively mimicking the biological functions of perforin and granzymes released by CTLs to destroy cancer cells. As expected, the CTLiMSs demonstrated exceptional in vitro anticancer activity, inducing cancer cell apoptosis and exhibiting strong antiproliferative effects. Notably, CTLiMS treatment was demonstrated to induce immunogenic cell death of cancer cells as a result of Ca²⁺ and MMAE influx and subsequent production of reactive oxygen species. The animal studies demonstrated that the CTLiMS treatment led to efficient repression of the tumor growth. Furthermore, the CTLiMS administration resulted in favorable antitumor immunotherapeutic effects, as shown by significant inhibition of distant tumors, increased immune cell infiltration, and elevated plasma levels of pro-inflammatory cytokines. This pilot study using CTLiMSs for cancer immunotherapy offers an innovative bionic strategy for the future advancement of adoptive T cell therapy.