A Multifunctional Biomimetic Nanoplatform for Dual Tumor Targeting-Assisted Multimodal Therapy of Colon Cancer.

The biomimetic nanoparticles (NPs) possessing abilities of tumor targeting and multimodal therapy show great potential for efficient combat of colon cancer. Herein, we developed a multifunctional biomimetic nanoplatform (Fe ₃ O ₄ @PDA@CaCO ₃ -ICG@CM) based on CaCO ₃ -modified magnetic polydopamine (PDA) loaded with indocyanine green (ICG), which was encapsulated by a mouse lymphoma cell (EL4) membrane (CM) expressing functional proteins (i.e., lymphocyte function-associated antigen 1, LFA-1; transforming growth factor-β receptor, TGF-βR; programmed cell death protein 1, PD-1; and factor related apoptosis ligand, FasL). Under magnetic attraction and LFA-1/PD-1-mediated endocytosis, Fe ₃ O ₄ @PDA@CaCO ₃ -ICG@CM efficiently targeted CT26 colon tumor cells. The released calcium ion (Ca ²⁺ ) from the NPs triggered by acidic tumor microenvironment, the enhanced photothermal effect contributed by the combination of PDA and ICG, and FasL's direct killing effect together induced tumor cells apoptosis. Moreover, the apoptosis of CT26 cells induced immunogenic cell death (ICD) to promote the maturation of dendritic cells (DCs) to activate CD4 ⁺ /CD8 ⁺ T cells, thereby fighting against tumor cells, which could further be boosted by programmed death-ligand 1 (PD-L1) blockage and transforming growth factor-β (TGF-β) scavenging by Fe ₃ O ₄ @PDA@CaCO ₃ -ICG@CM. As a result, in vivo satisfactory therapeutic effect was observed for CT26 tumor bearing-mice treated with Fe ₃ O ₄ @PDA@CaCO ₃ -ICG@CM under laser irradiation and magnetic attraction, which could eradicate primary tumors and restrain distant tumors through dual tumor targeting-assisted multimodal therapy and eliciting adaptive antitumor immune response, generating the immune memory for inhibiting tumor metastasis and recurrence. Taken together, the multifunctional biomimetic nanoplatform exhibits superior antitumor effects, providing an insightful strategy for the field of nanomaterial-based treatment of cancer.