Cancer Stem Cells

Cancer stem cells (CSCs) are populations of cancer cells that have the properties of stem cells i.e. self-renewal and ability to generate differentiated progenies. CSCs have high plasticity, which changes their phenotypic and functional appearance. They have important roles in tumor development, expansion, resistance, relapse and metastasis. Multiple studies have shown that CSCs originate from non-malignant stem or progenitor cells. Inhibition of developmental signaling pathways that are critical for stem and progenitor cell homeostasis and function has important implications in strategies to target CSCs in cancer research.

Studies have shown that CSCs develop several mechanisms to protect themselves from toxins and genotoxic stress, including enhanced DNA damage repair capacity, increased expression of drug transporters, maintenance of a low reactive oxygen species (ROS) environment, and recruitment of a protective niche. Therefore, targeting signaling pathways that are required to maintain stem cells is the current therapeutic strategy for CSCs. For example, hedgehog pathway, Notch and Wnt signaling pathways.

Newly developed drugs targeting surface markers of CSCs opens the new avenues for cancer therapy, such as CD44, CD133, EpCAM, Sox2, and Oct-3/4.