Figure 7
From: Macrophages may promote cancer growth via a GM-CSF/HB-EGF paracrine loop that is enhanced by CXCL12
GM-CSF/HB-EGF paracrine loop between mononuclear phagocytes and cancer cells. (A) HeLa and DLD-1 cells produced GM-CSF following stimulation with 200 ng/mL CXCL12 and/or 25 ng/mL HB-EGF or supernatants obtained by treating human mononuclear phagocytes (Mø SN) with 25 ng/mL GM-CSF for 24 hours. (B) RT-PCR for GM-CSF in HeLa cells and Northern blot for HB-EGF in Mø stimulated as noted in the captions. (C) Mø upregulated HB-EGF surface expression following stimulation with GM-CSF, CXCL12 or cancer supernatants (cancer SN) that were obtained by GM-CSF-positive HeLa/DLD-1 cells. (D) Mø released HB-EGF (p < 0.05) upon GM-CSF or CXCL12 stimulation, as measured by a specific ELISA. Representative pictures or the means ± SD out of 10 experiments are shown. (E) Mechanistic representation of paracrine loops as suggested by the experimental findings.