Engineering Nanoscale Artificial Antigen-Presenting Cells by Metabolic Dendritic Cell Labeling to Potentiate Cancer Immunotherapy.

Nanoscale artificial antigen-presenting cells (aAPCs) are promising to activate T cells directly for cancer immunotherapy, while feasible and flexible strategy to develop nanoscale aAPCs remains highly desirable. Metabolic glycoengineering is used to decorate chemical tags on cells which enables bioorthogonal chemical conjugation of functional molecules. Herein, we develop a nanoscale aAPC by metabolic dendritic cell (DC) labeling to mobilize T-cell based antitumor immunity. We coat azido-labeled DC membrane on imiquimod-loaded polymeric nanoparticles and sequentially modify anti-CD3ε antibody via click chemistry. The nanoscale aAPCs perform improved distribution in lymph nodes and stimulate T cells and resident APCs. Significant inhibition of tumor inoculation and growth is observed after the vaccination, which can be further improved by combining antiprogrammed cell death receptor 1 (PD1) therapy. Our results demonstrate the promising application of metabolically labeled DCs for designing nanoscale aAPCs, which provide a simple and general strategy to potentiate cancer immunotherapy.

Smart Nanosized Drug Delivery Systems Inducing Immunogenic Cell Death for Combination with Cancer Immunotherapy.

Cancer immunotherapy, which suppresses tumor relapse and metastasis by boosting host immunity and inducing long-term immune memory effects, is emerging as a vital approach to improve the prognosis of patients. Although remarkable efficacy has been observed in some patients, challenges including low response rate, drug resistance, and immune-related adverse effects still limit the clinical application of cancer immunotherapy in broad types of tumors. Immunotherapeutic agents are used to enhance tumor immunogenicity and reverse the effects of the immunosuppressive tumor microenvironment (ITM), but the benefits of monotherapy are mild and transient due to off-target distribution of drugs. To overcome these issues, smart nanosized drug delivery systems (sNDDS) have been developed to enhance tissue specificity, co-deliver multiple drugs, prime immune cells, and amplify immune responses in tumors. Moreover, accumulating knowledge in cancer biology, immunology, and material science has also greatly promoted the development of sNDDS for enhancing cancer immunotherapy.In this Account, we will discuss the approaches of our group in designing sNDDS to induce immunogenic cell death (ICD) for combination with cancer immunotherapy. We propose a brief overview on the design of nanocarriers, intelligent moieties and immunotherapeutic agents in sNDDS. Then, we discuss the strategies to remodel ITM by leveraging ICD as well as cooperating with programmed cell death protein 1 ligand blockade and indoleamine 2,3-dioxygenase 1 inhibition. We have synthesized a series of stimuli-responsive polymers and prodrugs to fabricate sNDDS and have integrated multiple immunotherapeutic drugs into one platform for combinational immunotherapy. Last, we present an outlook on future design of sNDDS and possible directions for enhancing cancer immunotherapy. Building on the concept of enhancing tumor immunogenicity and reversing ITM, we hope this Account will contribute to the rational design of sNDDS for co-delivery of multiple drugs with amplified immunotherapeutic efficacy.

Engineering Polymeric Prodrug Nanoplatform for Vaccination Immunotherapy of Cancer.

Neoantigen-based cancer vaccines are promising for boosting cytotoxic T lymphocyte (CTL) responses. However, the therapeutic effect of cancer vaccines is severely blunted by functional suppression of the dendritic cells (DCs). Herein, we demonstrated an acid-responsive polymeric nanovaccine for activating the stimulator of interferon genes (STING) pathway and improving cancer immunotherapy. The nanovaccines were fabricated by integrating an acid-activatable polymeric conjugate of the STING agonist and neoantigen into one single nanoplatform. The nanovaccines efficiently accumulated at the lymph nodes for promoting DC uptake and facilitating cytosol release of the neoantigens. Meanwhile, the STING agonist activated the STING pathway in the DCs to elicit interferon-ß secretion and to boost T-cell priming with the neoantigen. The nanovaccine dramatically inhibited tumor growth and occurrence of B16-OVA melanoma and 4T1 breast tumors in immunocompetent mouse models. Combination immunotherapy with the nanovaccines and anti-PD-L1 antibody demonstrated further improved antitumor efficacy in a 4T1 breast tumor model.

Walking Dead Tumor Cells for Targeted Drug Delivery Against Lung Metastasis of Triple-Negative Breast Cancer.

Lung metastasis is challenging in patients with triple-negative breast cancer (TNBC). Surgery is always not available due to the dissemination of metastatic foci and most drugs are powerless because of poor retention at metastatic sites. TNBC cells generate an inflamed microenvironment and overexpress adhesive molecules to promote invasion and colonization. Herein, "walking dead" TNBC cells are developed through conjugating anti-PD-1 (programmed death protein 1 inhibitor) and doxorubicin (DOX)-loaded liposomes onto cell corpses for temporal chemo-immunotherapy against lung metastasis. The walking dead TNBC cells maintain plenary tumor antigens to conduct vaccination effects. Anti-PD-1 antibodies are conjugated to cell corpses via reduction-activated linker, and DOX-loaded liposomes are attached by maleimide-thiol coupling. This anchor strategy enables rapid release of anti-PD-1 upon reduction conditions while long-lasting release of DOX at inflamed metastatic sites. The walking dead TNBC cells improve pulmonary accumulation and local retention of drugs, reprogram the lung microenvironment through damage-associated molecular patterns (DAMPs) and PD-1 blockade, and prolong overall survival of lung metastatic 4T1 and EMT6-bearing mice. Taking advantage of the walking dead TNBC cells for pulmonary preferred delivery of chemotherapeutics and checkpoint inhibitors, this study suggests an alternative treatment option of chemo-immunotherapy to augment the efficacy against lung metastasis.

Phospholipid-mimic oxaliplatin prodrug liposome for treatment of the metastatic triple negative breast cancer.

A phospholipid-mimic oxaliplatin prodrug (Oxalipid) was synthesized, which could self-assemble into a liposomal nanostructure with a drug loading ratio as high as 27 wt%. Compared to free oxaliplatin, the resulting Oxalipid liposome displayed elongated blood circulation, increased tumor accumulation and improved anticancer efficacy against the metastatic triple negative breast cancer (TNBC).

Triple-Layered pH-Responsive Micelleplexes Loaded with siRNA and Cisplatin Prodrug for NF-Kappa B Targeted Treatment of Metastatic Breast Cancer.

The combination of chemotherapy and RNA interference is a promising approach for efficient cancer therapy. However, the success of such a strategy is hampered by the lack of suitable vectors to coordinate small interfering RNA (siRNA) and chemotherapeutic drug into one single platform. We herein report a novel triple-layered pH-responsive micelleplex loading siRNA and alkylated cisplatin prodrug for NF-Kappa B targeted treatment of metastatic breast cancer. The micelles were self-assembled from poly(ethylene glycol)-block-poly(aminolated glycidyl methacrylate)-block-poly(2-(diisopropyl amino) ethyl methacrylate) (PEG-b-PAGA-b-PDPA) triblock copolymers. At pH 7.4, the cisplatin prodrug was encapsulated in the hydrophobic PDPA core and siRNA was loaded on the positively charged PAGA interlayer to form the micelleplexes. The PEG corona can prevent protein absorption during blood circulation, minimize non-specific interaction with the reticuloendothelial system, and prolong the systemic circulation of the micelleplexes. The positively charged PAGA interlayer can facilitate deep tumor penetration of the micelleplexes, which, upon cellular uptake, are dissociated in the early endosomes to release anticancer drug payload due to protonation of the PDPA core. Using a 4T1 breast cancer model, we demonstrate that this novel micelleplex co-loaded with cisplatin prodrug and siRNA-p65 is able to simultaneously inhibit tumor growth and suppress distant metastasis of the cancer cells by downregulating NF-kappa B expression. The results reported in this study suggest that siRNA and anticancer drug co-delivery using pH-responsive micelleplexes is a promising strategy for efficient treatment of metastatic cancer.

The targeted delivery of anticancer drugs to brain glioma by PEGylated oxidized multi-walled carbon nanotubes modified with angiopep-2.

In this study, a dual-targeting drug delivery system based on PEGylated oxidized multi-walled carbon nanotubes (O-MWNTs) modified with angiopep-2 (O-MWNTs-PEG-ANG) was successfully developed for treatment of brain glioma. O-MWNTs can not only distribute in brains but also accumulate in tumors, and have ultrahigh surface area with remarkably high loading anticancer drug of doxorubicin (DOX), which was selected as drug carrier. Angiopep-2 can specifically combine to the low-density lipoprotein receptor-related protein (LRP) receptor overexpressed on the blood-brain barrier (BBB) and glioma cells, which was selected as targeting ligand. The cooperative dual-targeting to brain glioma by O-MWNTs-PEG-ANG was evaluated by intracellular tracking in vitro and fluorescence imaging in vivo, which demonstrated that the combination of O-MWNTs-PEG and angiopep-2 constituted an ideal dual-targeting drug delivery system. The anti-glioma effect of DOX-loaded O-MWNTs-PEG-ANG (DOX-O-MWNTs-PEG-ANG) was assessed by C6 cytotoxicity and median survival time of glioma bearing mice, which showed a better anti-glioma effect than DOX. The biological safety of O-MWNTs-PEG-ANG was evaluated by BCEC and C6 cytotoxicity, hematology analysis and CD68 immunohistochemical analysis, which proved O-MWNTs-PEG-ANG was good biocompatibility and low toxicity. The biological safety of DOX-O-MWNTs-PEG-ANG was evaluated by histopathological analysis, which suggested a lower cardiac toxicity than DOX. In conclusion, O-MWNTs-PEG-ANG is a promising dual-targeting carrier to deliver DOX for the treatment of brain tumor.