Human Adipose Tissue Stem Cells Promote the Growth of Acute Lymphoblastic Leukemia Cells in NOD/SCID Mice.

In this study, the effect of adipose tissue stem cells (ASCs) on the growth of acute lymphoblastic leukemia (ALL) cells was examined in an in vivo model. We established ALL cell lines expressing firefly luciferase (ALL/fLuc) by lentiviral infection that were injected intraperitoneally to NOD/SCID mice. The luciferase activities were significantly higher in mice co-injected with 105 ALL/fLuc cells and ASCs than in those injected with ALL/fLuc cells alone. Co-injection of 105 ALL/fLuc cells and ASCs in differing ratios into mice gradually increased the bioluminescence intensity in all groups, and mice co-injected with 1 or 2 × 106 ASCs showed higher bioluminescence intensity than those receiving lower numbers. Interestingly, in the mice injected with 105 or 107 ALL/fLuc cells alone, the formation of tumor masses was not observed for at least five weeks. Moreover, co-injection of 107 ALL/fLuc cells and 5 × 105 ASCs into mice increased the bioluminescence intensity in all groups, and showed significantly higher bioluminescence intensity compared to mice co-injected with human normal fibroblast HS68 cells. Overall, ASCs promote the growth of ALL cells in vivo, suggesting that ASCs negatively influence hematologic malignancy, which should be considered in developing cell therapy using ASCs.