Fig. 3
From: Macrophages and cancer stem cells: a malevolent alliance
The soluble protein GPNMB produced by macrophages induces cancer stemness via CD44 and IL-33. Cancer cells stimulate in macrophages the production of GPNMB by M-CSF and tumor derived factors. GPNMB can be cleaved from the membrane by metalloproteinases, such as ADAM10. Soluble GPNMB binds to the CD44 receptor and triggers the release of IL-33. This cytokine, through the binding to its receptor IL-1RL1, is able to expand the population of CSCs, and to stimulate macrophages to produce TGFβ, promoting CSC invasion and resistance to drugs. This figure was made with Servier Medical Art templates, which are licensed under a Creative Commons Attribution 3.0. Unported License (https://smart.servier.com)