Fighting Immune Cold and Reprogramming Immunosuppressive Tumor Microenvironment with Red Blood Cell Membrane-Camouflaged Nanobullets

Abstract

Nanomedicine, acting as the magic bullet, is capable of combining immunotherapy with other treatments to reverse a cold tumor (immune depletion) into a hot tumor. However, how to comprehensively inhibit the immunosuppressive tumor microenvironment (TME) remains a major challenge for immunotherapy to achieve the maximum benefits. Thus, a strategy that can simultaneously increase the recruitment of tumor infiltrating lymphocytes (TILs) and comprehensively reprogram the immunosuppressive TME is still urgently needed. Herein, a thermal-sensitive nitric oxide (NO) donor S-nitrosothiols (SNO)-pendant copolymer (poly­(acrylamide-co-acrylonitrile-co-vinylimidazole)-SNO copolymer, PAAV-SNO) with upper critical solution temperature (UCST) was synthesized and employed to fabricate an erythrocyte membrane-camouflaged nanobullet for codelivery of NIR II photothermal agent IR1061 and indoleamine 2,3-dioxygenase 1 (IDO-1) inhibitor 1-methyl-tryptophan (1-MT). This multifunctional nanobullet possessed long circulation in vivo, enhanced accumulation at the tumor site, and therapeutics-controlled release by NIR II laser, thereby it could avoid unspecific drug leakage while enhancing biosecurity. More importantly, the immunogenic cell death (ICD) induced by local hyperthermia from photothermal therapy (PTT) could be conducive for the increased recruitment of CD8+ cytotoxic T lymphocytes (CTLs) at the tumor site. Furthermore, through interfering in the IDO-1 activity by 1-MT and normalizing the tumor vessels by in situ generated NO, the immunosuppressive TME was comprehensively reprogrammed toward an immunostimulatory phenotype, achieving the excellent therapeutic efficacy against both primary breast cancer and metastases. Collectively, this multifunctional nanobullet described in this study developed an effective and promising strategy to comprehensively reprogram suppressive TME and treat “immune cold” tumors.

Immunogenic-cell-killing and immunosuppression-inhibiting nanomedicine

“…In addition, the enhanced synergistic effect of PTX and CUR that was mediated by HA-PAAVB NPs could inhibit primary breast cancer growth and their lung metastasis. Therefore, the intelligent drug delivery system [ [75] , [76] , [77] , [78] , [79] , [80] , [81] , [82] , [83] , [84] ] based PAAVB copolymer presented in this paper could provide an effective platform that combines chemo- and immune-therapeutics for fighting against various malignant tumors.…”

Recent progress in targeted delivery vectors based on biomimetic nanoparticles

“…RBC-LIP-AmB exhibited a distinct ability to neutralize hemotoxin released by the pathogenic fungi, and protected the mice from Candida albicans infection as well as prolonged survival time. Other than the above, RBC membrane can camouflage bovine serum albumin for malignant melanoma metastasis 54 , perfluorocarbon for hypoxia alleviation 55 , ZGGO@mSiO2 for bioimaging and therapy of breast cancer 56 , PAAV-SNO copolymer for immune cold, and reprogramming immunosuppressive tumor therapy 57 .…”

Recent strategies for nano-based PTT combined with immunotherapy: from a biomaterial point of view

“…Results showed that both the primary tumor and distant tumor was suppressed significantly after the combinational therapy. Similarly, Yang and co-workers explored the anti-tumor effect of IR1061 mediated NIR II PTT combined with IDO inhibitor (1-MT) 97 . IR1061 and 1-MT were co-encapsulated into nanoparticles self-assembled by a poly (acrylamide-co-acrylonitrile-co-vinylimidazole)-S-nitrosothiols copolymer, PAAV-SNO).…”