Progression of Luminal Breast Tumors Is Promoted by Ménage à Trois between the Inflammatory Cytokine TNFα and the Hormonal and Growth-Supporting Arms of the Tumor Microenvironment

Figure 5

Combined stimulation of breast tumor cells by TNFα + Estrogen + EGF leads to potent induction in expression of CD44 and to emergence of a CD44^high/β1^high cell population. ((a), (B)) Determination of CD44 expression. Breast tumor cells were stimulated by (a1) TNFα, (a2) estrogen, (a3) EGF, or (B) TNFα + Estrogen + EGF (concentrations as in Figure 1) for three days. Non-stimulated: cells grown with the diluents of the above factors. The expression of CD44 on the surface of the cells was determined by FACS analyses, using specific Abs to CD44. Isotype: isotype matched Abs used as control in the FACS analyses. In all panels, the results are from a representative experiment of 𝑛≥3. (c) Coexpression of CD44 and β1. (c1) Non-stimulated: cells grown with the diluents of the above factors. (c2) Cells stimulated by TNFα + Estrogen + EGF (concentrations as in Figure 1). The expression of CD44 and β1 on the surface of the cells was determined by FACS analyses using specific Abs, with axes set based on staining with isotype matched control Abs. In all panels, the results are from a representative experiment of 𝑛≥3.