[Preparation and Tumor Targeting Analysis of Cell Membrane Nanovesicles Derived from Breast Cancer Cells].

Objective: To prepare cell membrane nanovesicles (NVs) derived from breast cancer cells, to explore their basic characteristics, tumor cell endocytosis, and in vivo distribution in a tumor-bearing mouse model, and to investigate their tumor targeting properties. Methods: 4T1 breast cancer cells were cultured in vitro. The cell membrane of 4T1 cells was isolated through ultracentrifugation and NVs were formulated with a liposome extruder. The size distribution of NVs was determined by way of dynamic light scattering, and the morphology properties of the NVs were examined with transmission electron microscope. The stability of NVs was analyzed by measuring the diameter changes of NVs submerged in phosphate-buffered saline (PBS). The biocompatibility of NVs was investigated by measuring the viability of dendritic cells treated with NVs at different concentrations (5, 10, 20, 50, and 100 mg·L -1) by CCK-8 assay. Fluorescence microscopy was used to analyze the cellular uptake of NVs by breast cancer cells. A mice model of breast cancer model was established with mice bearing subcutaneous xenograft of 4T1 cells. The mice were treated with Cy5.5-labeled NVs injected via the tail vein and the in vivo distribution of NVs was analyzed with an imaging system for small live animals. Results: The results showed that NVs derived from 4T1 breast cancer cells were successfully prepared. The NVs had a mean diameter of 123.2 nm and exhibited a hollow spherical structure under transmission electron microscope. No obvious change in the size of the NVs was observed after 7 days of incubation in PBS solution. CCK-8 assay results showed that the viability of dendritic cells treated with NVs at different concentrations was always higher than 90%. Fluorescence microscopic imaging showed that NVs could be efficiently internalized into breast cancer cells. in vivo biodistribution analysis revealed that breast cancer cell-derived NVs showed higher distribution in tumor tissue than the NVs prepared with normal cells did. Conclusion: We successfully prepared cell membrane NVs derived from 4T1 breast cancer cells. These NVs had efficient cellular uptake by breast cancer cells and sound tumor targeting properties.

CD155-TIGIT Axis as a Therapeutic Target for Cancer Immunotherapy.

Immune checkpoint inhibitors (ICIs) have shown unprecedented efficacy in treating many advanced cancers. Although FDA-approved ICIs have shown promising efficacy in treating many advanced cancers, their application is greatly limited by the low response rate, immune-related adverse events (irAE), and drug resistance. Developing novel ICIs holds great promise to improve the survival and prognosis of advanced cancer patients. T-Cell immunoglobulin and ITIM domain (TIGIT) is an inhibitory receptor expressed on T cells, natural killer (NK) cells, and T regulatory cells. Increasing reports have shown that the disrupting CD155-TIGIT axis could activate the immune system and restore antitumor immune response. This review briefly summarized the role of TIGIT in tumor immune escape and targeting CD155-TIGIT axis drugs in preclinical and clinical trials for cancer immunotherapy.

Engineered elastin-like polypeptide-based hydrogel delivering chemotherapeutics and PD-L1 antibodies for potentiated cancer immunotherapy.

Immune checkpoint inhibitors (ICIs) have effectively eradicated advanced tumors by inducing durable and systematic antitumor immune responses. However, when used as a standalone treatment, ICIs typically exhibit a low response rate in many cancers. In this study, we engineered an in situ-formed gel depot using elastin-like polypeptides (ELPs) to efficiently deliver PD-L1 antibodies (aPD-L1) and gemcitabine (GEM) for enhanced immunotherapy in melanoma. Sustainably released chemotherapeutics from gel depots could kill melanoma cells and promote PD-L1 upregulation in tumor cells. Moreover, aPD-L1/GEM-encapsulated ELP hydrogel promoted a 3.0-fold increase of tumor-infiltrated CD8+ T cells and 60% Tregs depletion compared with PBS group, eliciting a robust antitumor immune response for immunotherapy in melanoma mouse models. This research highlights the promising potential of ELP-based hydrogels in delivering ICIs and chemotherapeutic agents for potentiated cancer immunotherapy.