Further describing this innovative concept, in a high-impact article published in the January 2010 issue of Nature Reviews Cancer, Drs. Rafii and Butler, and Dr. Hideki Kobayashi, who is also a co-author of the current study, have elaborated on specific endothelial cell-produced growth factors that promote the growth of tumor cells besides stem cells.
Development of the vascular-cell technology that supports long-lasting growth of stem cells will also allow scientists to generate abundant sources of functional and malignant stem cells for genetic and basic studies. This study has also resolved a long-standing controversy in which several groups had claimed that bone-forming cells (osteoblasts) exclusively support the expansion of blood-forming stem cells. "However, using a highly sophisticated molecular imaging approach, we show that regenerating blood-forming stem cells in the bone marrow are in intimate contact with the blood vessels, indicating that endothelial cells are the predominant regulator of stem cell repopulation in the adult bone marrow," states Dr. Daniel Nolan, a senior scientist in Dr. Rafii's lab and a co-author of the new study.
One other important concern addressed in this study was whether forced expansion of the stem cells over a long period of time would induce cancerous mutations in the stem cells. However, the authors of this study show that, even after one year, there was no indication of tumor formation, such as leukemias, when the expanded stem cells were transplanted back into mice. This suggests that the endothelial cells provide a milieu that
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New York- Presbyterian Hospital/Weill Cornell Medical Center/Weill Cornell Medical College