Targeted Antiepidermal Growth Factor Receptor (Cetuximab) Immunoliposomes Enhance Cellular Uptake In Vitro and Exhibit Increased Accumulation in an Intracranial Model of Glioblastoma Multiforme

Figure 1

Representative micrographs showing expression of epidermal growth factor receptor (EGFR) in vitro and in vivo. (A), (C) In vitro expression of EGFR in U87 mg (A) and U251 mg (C) cell lines using fluorescent antibodies. The cells are labeled using an anti-human EGFR primary antibody (green) and cellular nuclei demonstrated with 4′,6-diamidino-2-phenylindole (DAPI) (blue) Application of nonimmune isotypic immunoglobulins reveals no labeling of U87 mg (B) and U251 mg (D) cells. (E)–(G) In vivo expression of EGFR in the U87 mg intracranial xenograft model. (E), EGFR expression detected in U87 mg cells using a fluorescent secondary antibody (green) shown at low-power magnification. The U87 mg cells form a prominent tumor with a clear demarcation that leaves the surrounding normal brain tissue unlabeled. When examined at larger magnification (cropped areas in (E)), it is evident that EGF-receptors are expressed by U87 mg cells forming the xenograft (F), and not in cells of the normal brain (G). Scale bars = 50 μm ((A), (B), (C), (D), (F), (G)), 100 μm (E).