[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 distribution in a tumor-bearing mouse model, and to investigate their tumor targeting properties.

Methods: 4T1 breast cancer cells were cultured . 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 ) 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 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. 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.