OBJECTIVETo investigate the expression of cell surface E-cadherin in leukemia cell and the correlation of cell membrane localization of beta-catenin with E-cadherin expression.

METHODSBone marrow samples from 46 patients with acute leukemia and 17 normal donors were analyzed. Cell surface expression of E-cadherin and membrane localization of beta-catenin were labeled by immunofluorescence and analyzed with a laser scanning confocal fluorescence microscope in 14 specimens.

RESULTSCell surface E-cadherin expression level was significantly lower in leukemia cells (with the median fluorescent intensity of 16.78) than in normal hematopoietic progenitors (26.03). Correlation analysis showed that cell membrane localization of beta-catenin was correlated with E-cadherin expression (r = 0.74, P = 0.002). After E-cadherin was induced to express in leukemic cell by 5-Aza-CdR, membranous expression of beta-catenin was elevated while the nuclear expression reduced, indicating that E-cadherin-mediated adhesions could recruit beta-catenin to cell membrane.

CONCLUSIONThe loss of E-cadherin in leukemia cells may result in beta-catenin translocating to the nuclear and transcriptional activation of its target genes.