Stem cells are defined as cells that have the ability to perpetuate through self-renewal, and develop into mature cells of a particular tissue through differentiation. Appropriate controls of stem cell functions are critical for maintaining tissue homeostasis. We have revealed that genes that are involved in longevity, including FOXO and mTOR pathways, contribute to the maintenance of stem cell self-renewal capacity. Thus, signaling pathways for control of intracellular metabolism may play a critical role in stem cell regulation.
Recent evidence has demonstrated that in tumors only a minority of cancer cells has the capacity to proliferate extensively and form new tumors. These tumor-initiating cells, which are called cancer stem cells, are thought as a novel target for cancer therapy. The investigation of distinct and parallel roles in normal stem cells and cancer stem cells will contribute to the design of cancer therapy without damaging normal tissues.
Fig.1 Nutrient sensor signals
Fig.2 mTOR and FOXO pathways in quiescent hematopoietic stem cells
Fig.3 FOXOactivation for drug-resistance of leukemia stem cells
Fig.4 mTOR complex in leukemia stem cells