Fig. 2
Transferrin-functionalized liposomes achieve receptor-mediated transcytosis and delivery to intracranial models of GBM. a Immunohistochemistry demonstrates expression of transferrin receptor (α-Tf receptor) in the endothelium of tumor-associated blood vessels and in tumor tissue of U87MG and GL261 glioma brain tumors. Mouse IgG served as a negative control for non-specific antibody staining (IgG control). Scale bar = 20 μm. b Representative western blot and quantification shows ~1.4-fold increased expression of transferrin receptor in U87MG compared to GL261 cells. Data presented as mean ± SEM of three separate experiments. c Immunofluorescence staining demonstrates time-dependent intracellular uptake of Tf-NPs but not PEG2K-Cy5.5 (PEG-NP) liposomes in U87MG and GL261 cells in vitro. Tf-NPs co-localize to late endosomal/lysosomal compartments (LAMP-1). Nuclei were visualized using DAPI counterstain (DAPI). Scale bar = 10 μm. d Flow cytometry plots and quantification of cellular PEG-NP or Tf-NP signal in U87MG and GL261 cells. Data presented as mean ± SEM of three separate experiments. Statistical analysis performed using Student’s t-test (***p < 0.001). e Multiphoton images of PEG-NP or Tf-NPs (red) at the site of GFP-expressing U87MG and GL261 intracranial gliomas (green). Scale bars = 6.25 μm or 12.5 μm
