Store-Operated Calcium Entry and Its Implications in Cancer Stem Cells.

Tumors are composed by a heterogeneous population of cells. Among them, a sub-population of cells, termed cancer stem cells, exhibit stemness features, such as self-renewal capabilities, disposition to differentiate to a more proliferative state, and chemotherapy resistance, processes that are all mediated by Ca. Ca homeostasis is vital for several physiological processes, and alterations in the patterns of expressions of the proteins and molecules that modulate it have recently become a cancer hallmark. Store-operated Ca entry is a major mechanism for Ca entry from the extracellular medium in non-excitable cells that leads to increases in the cytosolic Ca concentration required for several processes, including cancer stem cell properties. Here, we focus on the participation of STIM, Orai, and TRPC proteins, the store-operated Ca entry key components, in cancer stem cell biology and tumorigenesis.