Cancer Stem Cells and Their Microenvironment: Biology and Therapeutic Implications

Figure 1

The cross talks between CSCs and their niches. CSCs reside in their habitats, which are specific microenvironments within the tumor consisting of CAFs, masts cells, neutrophils, perivascular cells, adipocytes, ECM, and immune-suppressive cells, as well as hypoxia. By providing various paracrine factors or via direct cell-cell contact, these niches play a crucial role in maintaining CSC plasticity by regulating pathways or transcription factors involved in self-renewal or EMT process. Reciprocally, CSCs can actively recruit some of these niche components to create a microenvironment that is favorable for its survival. For example, CSCs can secrete VEGF and SDF-1 to recruit perivascular cells or produce G-CSF to recruit MDSCs into the tumor microenvironment.