The Wilms tumor suppressor gene WT1 induces G1 arrest and apoptosis in myeloblastic leukemia M1 cells

WT1 was isolated as a tumor suppressor gene of Wilms tumor. However, high expression of WT1 correlates with poor prognosis in acute leukemia. In addition suppression of WT1 expression by WT1 anti-sense oligonucleotide inhibits proliferation of leukemia cells, suggesting that WT1 is important for their proliferation. To further elucidate the biological significance of WT1 in leukemic cell growth, we overexpressed exogenous WT1 in murine M1 myeloblastic leukemia cells using the isopropyl-beta-D-thiogalactoside (IPTG)-controlled expression system. We found that induction of one splicing variant of WT1 [WT1-17AA(+)-KTS(-)] in M1 cells induces cell cycle arrest and apoptotic cell death. These results suggest that the role of WT1 is different depending on the type of leukemia cell in which it is expressed.