Promotion of the self-renewal capacity of human acute leukemia cells by Wnt3A.

BACKGROUND Wnt/beta-catenin signaling is involved in the growth of various types of cancer cells. Wnt3A has been reported to promote the self-renewal of hematopoietic stem cells. MATERIALS AND METHODS The effects of recombinant Wnt3A protein on the in vitro growth of four acute myeloid leukemia (AML) and four acute T-lymphoblastic leukemia (T-ALL) cell lines was examined. RESULTS Wnt3A stimulation either had no effect on, or slightly suppressed, the short-term growth of these cell lines. In three cell lines, Wnt3A promoted clonogenic cell recovery after suspension culture, suggesting the promotion of the self-renewal capacity of leukemic stem or progenitor cells. Immunoblot analysis showed that Wnt3A stimulation reduced phosphorylated beta-catenin and increased beta-catenin in these cells, indicating that Wnt3A stimulation activated Wnt/beta-catenin signaling. CONCLUSION Wnt3A stimulation did not promote the growth of whole cell populations, but did promote the self-renewal of leukemic stem/progenitor cells in some AML and T-ALL cell lines.