Abstract
Combination therapy that could better balance immune activation and suppressive signals holds great potential in cancer immunotherapy. Herein, we serendipitously found that the pH-responsive nanovesicles (pRNVs) self-assembled from block copolymer polyethylene glycol-b-cationic polypeptide can not only serve as a nanocarrier but also cause immunogenic cell death (ICD) through preapoptotic exposure of calreticulin. After coencapsulation of a photosensitizer, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) and an indoleamine 2,3-dioxygenase inhibitor, indoximod (IND), pRNVs/HPPH/IND at a single low dose elicited significant antitumor efficacy and abscopal effect following laser irradiation in a B16F10 melanoma tumor model. Treatment efficacy attributes to three key factors: (i) singlet oxygen generation by HPPH-mediated photodynamic therapy (PDT); (ii) increased dendritic cell (DC) recruitment and immune response provocation after ICD induced by pRNVs and PDT; and (iii) tumor microenvironment modulation by IND via enhancing P-S6K phosphorylation for CD8+ T cell development. This study exploited the nanocarrier to induce ICD for the host’s immunity activation. The “all-in-one” smart nanovesicles allow the design of multifunctional materials to strengthen cancer immunotherapy efficacy.
