In situ cancer stem cell vaccination and immune activation enabled by CSC-specific ligand screening

Cancer stem cells (CSCs) are pivotal drivers of therapeutic resistance, tumor recurrence, and metastasis due to their self-renewal capacity and localization in poorly vascularized, hypoxic tumor niches. These characteristics limit the efficacy of conventional therapies and underscore the need for CSC-targeted strategies. In this study, we propose a novel in situ cancer vaccine strategy specifically targeting CSCs to overcome these limitations. Using phage display screening, we identified a CD133-targeting peptide and constructed a CD133-functionalized PLGA nanoparticle (CD133-PLGA@DOX) for the selective delivery of doxorubicin to CD133 + CSCs. This nanoplatform achieved precise CSC targeting and induced effective cytotoxicity, particularly against CSCs enriched post-radiotherapy. Importantly, targeted CSC destruction led to the local release of CSC antigens, which served as an endogenous antigen reservoir and triggered a potent in situ vaccine-like immune response. Treatment with CD133-PLGA@DOX significantly promoted dendritic cell maturation, enhanced antigen-specific cytotoxic T cell infiltration, and established long-term immune memory. This strategy—simultaneous CSC eradication and in situ CSC antigen release—demonstrates strong therapeutic efficacy and holds promise for preventing tumor recurrence and overcoming resistance in solid tumors.