Immunotherapy combining tumor and endothelium cell lysis with immune enforcement by recombinant MIP-3α Newcastle disease virus in a vessel-targeting liposome enhances antitumor immunity.

BACKGROUND: Several agents for oncolytic immunotherapy have been approved for clinical use, but monotherapy is modest for most oncolytic agents. The combination of several therapeutic strategies through recombinant and nanotechnology to engineer multifunctional oncolytic viruses for oncolytic immunotherapy is a promising strategy. METHODS: An endothelium-targeting iRGD-liposome encapsulating a recombinant Newcastle disease virus (NDV), which expresses the dendritic cell (DC) chemokine MIP-3α (iNDV3α-LP), and three control liposomes were constructed. MIP-3α, HMGB1, IgG, and ATP were detected by western blotting or ELISA. The chemotaxis of DCs was examined by Transwell chambers. The phenotypes of the immune cells were analyzed by flow cytometry. The antitumor efficiency was investigated in B16 and 4T1 tumor-bearing mice. Immunofluorescence and immunohistochemistry were used to observe the localization of liposomes, molecular expression and angiogenesis. Synergistic index was calculated using the data of tumor volume, tumor angiogenesis and tumor-infiltrating lymphocytes. RESULTS: Compared with NDV-LP, treatment with iNDV3α-LP and NDV3α-LP induced stronger virus replication and cell lysis in B16 and 4T1 tumor cells and human umbilical vein endothelial cells (HUVECs) with the best response observed following iNDV3α-LP treatment. B16 and 4T1 cells treated with iNDV3α-LP produced more damage-associated molecular pattern molecules, including secreted HMGB1, ATP, and calreticulin. Moreover, iNDV3α-LP specifically bound to αvß3-expressing 4T1 cells and HUVECs and to tumor neovasculature. Tumor growth was significantly suppressed, and survival was longer in iNDV3α-LP-treated B16-bearing and 4T1-bearing mice. A mechanism study showed that iNDV3α-LP treatment initiated the strongest tumor-specific cellular and humoral immune response. Moreover, iNDV3α-LP treatment could significantly suppress tumor angiogenesis and reverse the tumor immune suppressive microenvironment in both B16-bearing and 4T1-bearing mice. CONCLUSIONS: In this study, iNDV3α-LP had several functions, such as tumor and vessel lysis, MIP-3α immunotherapy, and binding to αvß3-expressing tumor and its neovasculature. iNDV3α-LP treatment significantly suppressed tumor angiogenesis and reversed the tumor immunosuppressive microenvironment. These findings offer a strong rationale for further clinical investigation into a combination strategy for oncolytic immunotherapy, such as the formulation iNDV3α-LP in this study.

Long Blood Residence and Large Tumor Uptake of Ruthenium Sulfide Nanoclusters for Highly Efficient Cancer Photothermal Therapy.

Transition metal sulfide (TMS) holds great potential in cancer photothermal therapy (PTT) because of the high absorbance in the near-infrared (NIR) region. The short blood circulation time and limited tumor accumulation of TMS-based photothermal agents, however, limit their applications. Herein, we design a novel TMS-based PTT agent, ruthenium sulfide-based nanoclusters (NCs), to overcome the current limitations. We firstly develop a simple method to prepare oleic acid coated ruthenium sulfide nanodots (OA-RuS1.7 NDs) and assemble them into water-soluble NCs via sequentially coating with denatured bovine serum albumin (dBSA) and poly(ethylene glycol) (PEG). The obtained PEG-dBSA-RuS1.7 NCs possess excellent photothermal conversion ability. More significantly, they exhibit enhanced blood circulation time and tumor-targeting efficiency in vivo compared with other TMS-based PTT nanoagents, which may be attributed to their appropriate hydrodynamic diameter (~70 nm) and an ideal charge (~0 mV). These characteristics help the PEG-dBSA-RuS1.7 NCs to escape the removal by the reticuloendothelial system (RES) and kidney. All these advantages enable the PEG-dBSA-RuS1.7 NCs to selectively concentrate in tumor sites and effectively ablate the cancer cells upon NIR irradiation.

The antitumour activities induced by pegylated liposomal cytochalasin D in murine models.

Cytochalasin D targets actin and is ubiquitous in eukaryotic cells. When cytochalasin D is used as a cytotoxic agent in cancer therapy, it causes significant side effects. To prevent this, cytochalasin D can be encapsulated in polyethylene liposomes. In this study, high-performance liquid chromatography observation of the biodistribution of pegylated liposomal cytochalasin D in tumour-bearing mice showed that liposomal cytochalasin D could be conveniently dissolved in water for i.v. injection and that it specifically accumulated in tumour tissues, more than natural cytochalasin D did. The half-time of liposomal cytochalasin D in the plasma was also significantly longer than that of natural cytochalasin D (4h versus 10 min). MTT 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that liposomal cytochalasin D treatment could cause significant inhibition of cell proliferation in vitro in a manner similar to that of natural cytochalasin D. The antitumour activities of liposomal cytochalasin D were investigated in B16 melanoma, CT26 colorectal carcinoma and H22 hepatoma models, and the results indicated that liposomal cytochalasin D could significantly inhibit tumour growth and prolong survival in a manner similar to that of cisplatin. TUNEL-based apoptosis assays showed that liposomal cytochalasin D induced significant tumour cell apoptosis. Significant inhibition of tumour angiogenesis was observed in mice treated with liposomal cytochalasin D. In addition, no significant side effects were observed in mice treated with liposomal cytochalasin D. Our results show that liposomal cytochalasin D increases solubility and bioavailability, a lower incidence of side effects and improves antitumour effects, indicating its potential as a chemical agent for cancer therapy.