Chapter 32 - Components of cancer stem cells microenvironment: influence on the tumorigenic property and stemness in cancer stem cells

Abstract

Cancer Stem Cells (CSCs) are an inconspicuous subpopulation of cells found in solid tumors that is responsible for tumor heterogeneity, therapeutic resistance, and relapse. They exhibit similar properties as normal stem cells, including self-renewal, multipotency, plasticity, and reversible dormancy. However, the evident dysregulation of stem cell signaling pathways, exposure to inflammation, and oxidative stress, as well as their interactions with the micro-niche, leads to differentiated CSCs. This altered phenotype promotes tumor aggression by increasing angiogenesis, metastasis, and chemoresistance in many cases. CSCs are heavily dependent on the “niche” they reside in and is referred to as the CSC microenvironment or CSC niche. This ecosystem of nonmalignant components and the malignant tumor along with the CSCs, carries out a constant cross talk that favors an immunosuppressive environment that caters regulation of several pathways necessary for progression of cancer. The sustenance of CSCs within the tumor microenvironment (TME) is influenced by various cytokine, chemokine, soluble secretions derived from the components of the TME. In this chapter, we will be discussing the role of the CSC microenvironment, which includes, stromal components, immune cells, structural components and hypoxia, to understand the mechanisms of tumor progression and cancer stemness to selectively target for effective anticancer therapy.