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Immune checkpoint blockade therapies, especially those targeting the programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) have achieved impressive clinical responses in multiple types of cancers. To optimize the therapeutic effect of the checkpoint antibodies, many strategies including targeting delivery, controlled release, and cellular synthesis have been developed. However, within these strategies, antibodies were attached to drug carriers by chemical bonding, which may affect the steric configuration and function of the antibodies. Herein, we prepared cluster of differentiation 64 (CD64), a natural catcher of the fragment crystalline (Fc) of monomeric immunoglobulin G (IgG), and over-expressed it on the cell membrane nanovesicles (NVs) as PD-L1 antibody delivery vehicle (CD64-NVs-aPD-L1), which was employed to disrupt the PD-1/PD-L1 immunosuppressive signal axis for boosting T cell dependent tumor elimination. Meanwhile, chemical immunomodulatory drug cyclophosphamide (CP) was also encapsulated in the vesicle (CD64-NVs-aPD-L1-CP), to simultaneously restrain the regulatory T cells (Tregs) and invigorate Ki67 + CD8 + T cells, then further enhance their anti-tumor ability. Methods : The cell membrane NVs overexpressing CD64 were incubated with PD-L1 antibody and chemotherapeutic agent CP to prepare CD64-NVs-aPD-L1-CP. Results: The CD64-NVs-aPD-L1-CP could simultaneously interrupt the immunosuppressive effect of PD-L1 and decrease the inhibition of Tregs, leading to tumor growth suppression and survival time extension. Conclusion: CD64-NVs are charismatic carriers to achieve both checkpoint blockade and immunomodulatory drugs for combined cancer immunotherapy., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Personalized cancer vaccines show great potential in cancer immunotherapy by inducing an effective and durable antitumor response. However, the limitation of neoantigen identification, low immunogenicity, and weak immune response hamper the development of personalized cancer vaccines. The surgically removed tumor contains tumor antigens specific to the patient, which provides a promising source for personalized cancer vaccines. Here, we utilized the surgically removed tumor to prepare a personalized photothermal vaccine combined with the PD-1 checkpoint blockade antibody to prevent tumor relapse and metastasis. Black phosphorus quantum dot nanovesicles (BPQD-CCNVs) coated with surgically removed tumor cell membrane were prepared and loaded into a thermosensitive hydrogel containing GM-CSF and LPS. The sustained release of GM-CSF from the hypodermic injection of Gel-BPQD-CCNVs effectively recruited dendritic cells to capture tumor antigen. NIR irradiation and LPS stimulated the expansion and activation of DCs, which then traveled to the lymph nodes to present antigen to CD8 + T cells. Moreover, the combination with PD-1 antibody significantly enhanced tumor-specific CD8 + T cell elimination of the surgical residual and lung metastatic tumor. Hence, our work may provide a promising strategy for the clinical development of a personalized cancer vaccine.

Basal-like breast cancer exhibits a triple-negative phenotype and has a poor prognosis, even with traditional chemical and anti-human epidermal growth factor receptor (HER) treatments. However, the high mutation rate of this obstinate cancer type renders it suitable for immunotherapy. Photothermal therapy (PTT) is a high-efficiency method for inducing tumor neoantigen release in situ, which has great potential for use in cancer immunotherapy. Here, we prepared a biomimetic black phosphorus quantum dot (BPQDs) formulation to induce breast cancer cell apoptosis in situ by near-infrared (NIR) laser irradiation to mobilize the immune system to eliminate the residual and metastatic cancer cells. Erythrocyte membranes (RMs) were used to coat the BPQDs, forming a BPQD-RM nanovesicle (BPQD-RMNV) biomimetic formulation that exhibited a long circulation time and tumor accumulation in vivo. The basal-like 4T1 breast tumor underwent apoptosis and necrosis with the irradiation and recruited dendritic cells (DCs) to capture the tumor antigens in vivo. Furthermore, programmed cell death protein 1 (PD-1) antibody (aPD-1) was employed to prevent the CD8 + T cells from exhaustion. Notably, BPQD-RMNV-mediated PTT combined with aPD-1 treatment significantly delayed residual and metastatic tumor growth in vivo. Hence, BPQD-RMNV-mediated PTT combined with immune checkpoint blockade antibody increased the infiltration and activity of CD8 + T cells in the tumor, which directly restrained basal-like breast tumor growth in vivo., (Copyright © 2019. Published by Elsevier B.V.)

Protein nanocapsules have exhibited promising potential applications in the field of protein drug delivery. A major issue with various promising nano-sized biotherapeutics including protein nanocapsules is that owing to their particle size they are subject to cellular uptake via endocytosis, and become entrapped and then degraded within endolysosomes, which can significantly impair their therapeutic efficacy. In addition, many nano-sized biotherapeutics could be also sequestered by autophagosomes and degraded through the autolysosomal pathway. Thus, a limiting step in achieving an effective protein therapy is to facilitate the endosomal escape and auto-lysosomal escape to ensure cytosolic delivery of the protein drugs. Here, we prepared a protein nanocapsule based on BSA (nBSA) and the BSA nanocapsules modified with a bilayer of lauric acid (LA-nBSA) to investigate the escape effects from the endosome and autophagosome. The size distribution of nBSA and LA-nBSA analyzed using DLS presents a uniform diameter centered at 10 nm and 16 nm. The data also showed that FITC-labeled nBSA and LA-nBSA were taken up by the cells mainly through Arf-6-dependent endocytosis and Rab34-mediated macropinocytosis. In addition, LA-nBSA could efficiently escape from endosomal before the degradation in endo-lysosomes. Autophagy could also sequester the LA-nBSA through p62 autophagosome vesicles. These two types of nanocapsules underwent different intracellular destinies and lauric acid (LA) coating played a vital role in intracellular particle retention. In conclusion, the protein nanocapsules modified with LA could enhance the protein nanocapsules escape from intercellular trafficking vesicles, and protect the protein from degradation by the lysosomes.