The receptor tyrosine kinase EphA2 promotes mammary adenocarcinoma tumorigenesis and metastatic progression in mice by amplifying ErbB2 signaling
J. Clin. Invest. Dana M. Brantley-Sieders, et al. 118:64 doi:10.1172/JCI33154 [Go to this article.]
Figure 3
Elevated EphA2 expression in MCF10A. ER2 cells enhances cell proliferation and invasiveness in vitro. (A) Parental MCF10A human breast cells and MCF10A.HER2 cells were transduced with adenoviruses (Ad) expressing EphA2 or control β-gal and plated on growth factor–reduced Matrigel to generate 3-dimensional spheroid cultures. After 10 days in culture, parental MCF10A cells and cells expressing Ad–β-gal formed small, round acinar structures, while MCF10A.HER2 cells formed larger colonies with irregular, invasive protrusions (arrows). Expression of Ad-EphA2 in MCF10A cells resulted in larger, irregular colonies, an effect that was amplified in MCF10A.HER2 cells (P < 0.05; single-factor ANOVA). Scale bar: 25 μm. (B) Cultures were stained with TO-PRO-3 iodide nuclear stain (red) and anti-Ki67 (green) and imaged by confocal microscopy. Confocal analysis revealed that parental and Ad–β-gal–transduced MCF10A formed uniform acinar structures composed of a single layer of epithelial cells surrounding a central lumen, while MCF10A.HER2 cells formed multiacinar structures with invasive protrusions (arrows) and a poorly defined lumen containing several cells. MCF10A cells transduced with Ad-EphA2 also formed multiacinar structures with a poorly defined lumen. Invasion and lumen filling were enhanced in MCF10A.HER2 cells overexpressing EphA2. Scale bar: 20 μm. EphA2 overexpression significantly enhanced proliferation (Ki67+ nuclei, arrows) within acinar structures formed by MCF10A and MCF10A.HER2 cells (P < 0.05; single-factor ANOVA). (C) Expression of adenoviral gene products and overexpression of ErbB2/HER2 in MCF10A.HER2 cells was confirmed by immunoblot, and uniform loading was verified by immunoblot for actin. Expression of p-Erk, total Erk, p-EphA2, and total EphA2 was also assessed by immunoblot.
