Quiescent, Slow-Cycling Stem Cell Populations in Cancer: A Review of the Evidence and Discussion of Significance
Figure 1
Pulse Chase Labeling and Chemotherapy Survival of Stem Cells. (a) Cell suspensions are labeled with BrdU or other label ((i) and (ii)). As rapidly proliferating transit amplifying cells divide, label is diluted among the daughter cells and eventually becomes undetectable (iii). Slow dividing stem cells retain label occasionally producing a new transit amplifying cell that will quickly dilute out residual label (iv). (b) Heterogeneous tumors are predicted to contain a population of slow cycling label retaining cells (i). Conventional chemotherapies target and kill rapidly proliferating cells, while quiescent cells survive ((ii) and (iii)). Cancer stem cells that survive chemotherapy re-enter the cell cycle and re-establish the tumor.
