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 8

In response to combined stimulation by TNFα + Estrogen + EGF, breast tumor cells acquire functional promalignancy properties. Breast tumor cells were stimulated by TNFα + Estrogen + EGF (concentrations as in Figure 1) for three days. Non-stimulated: cells grown with the diluents of the above factors. (a) Resistance to doxorubicin. Following their stimulation with the above-mentioned factors, the cells were replated with the aforementioned stimulation in the presence or absence of 1 μM doxorubicin for additional three days. Cell viability was determined by XTT assay. *𝑃<0.05 for the difference between stimulated and non-stimulated cells. The results are from a representative experiment of 𝑛≥3. (b) Release of promalignancy factors by the tumor cells, calculated per cell number. The expression of CXCL8 (b1) and CCL2 (b2) was determined in the CM of the cells by ELISA, at the linear range of absorbance. ***𝑃<0.001 for the differences between stimulated and non-stimulated cells. The results are from a representative experiment of 𝑛=3. (c) Release of functional MMPs, determined by zymography assays performed on cell CM. The bar graph shows the quantitative expression of MMPs, calculated per cell number. The results are from a representative experiment of 𝑛≥3.