Doxorubicin Delivered Using Nanoparticles Camouflaged with Mesenchymal Stem Cell Membranes to Treat Colon Cancer

Figures

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  Figure 1. Schematic of the preparation of DOX-SPIO@MSCs and the tumor-targeting drug delivery in vivo.

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  Figure 2. Characterization of DOX-SPIO@MSCs. (A) TEM image and (B) particle size distribution of DOX-SPIO@MSCs. (C) The SDS-PAGE images of the gel after Coomassie blue staining. Lane 1: MSCs lysates, Lane 2: membrane vesicles, Lane 3: DOX-SPIO@MSCs. (D) The stability of DOX-SPIO@MSCs in FBS and PBS was evaluated by monitoring variation in particle size for different time intervals. (E) DOX loading amount and Encapsulation efficiency in 0.1 mg SPIO with different DOX feeding amounts. (F) The drug release profiles of the DOX-SPIO at different pH values. (G) Fluorescence microscope images of DOX-SPIO@MSCs illustrating colocalization of DOX@SPIO (DOX channel) and MSVs (DIO channel) after being internalized by MC38 cells. Scale bar=40μm.

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  Figure 3. Intracellular distribution of NPs. (A) Prussian blue staining of MC38 cells after incubation with NPs for 4 h. Scale bar=20μm. (B) (a) Flow cytometry analysis of the MC38 cells treated with free DOX, DOX-SPIO and DOX-SPIO@MSCs for 30 and 240 min. (b) The DOX mean fluorescence intensity (MFI) of the MC38 cells. (C) Fluorescent staining images of the MC38 cells treated with different drugs for 240 min. Scale bar=40μm.

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  Figure 4. Biological responses in vitro (A) cytotoxicity of free DOX, DOX-SPIO and DOX-SPIO@MSCs against MC38 cells at different DOX concentrations. (B) Hemolysis study of SPIO with varied concentrations, using PBS as a negative control and water as a positive control. (C) Uptake of NPs by leukocytes from blood of a healthy donor in vitro. (D) Complement C3 opsonization of NPs. (E) Effect of NPs on complement activation and C5a generation.

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  Figure 5. DOX biodistribution in tissues. Ex vivo DOX fluorescence images (A) and average DOX intensity (B) of main organs and tumors at 24 h post-injection of free DOX, DOX-SPIO, DOX-SPIO@MSCs. Considering the distraction of self-fluorescence of mice, we used the group PBS to set as background. *P<0.01, versus DOX-SPIO (n=3).

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  Figure 6. In vivo therapeutic effect. (A) Relative tumor volumes and curves of the tumor-bearing mice with different treatment. (B) Digital images show tumors harvested from different groups. (C) H&E and TUNEL-stained tumor slice images (200× magnification).