Effect of WT1 gene expression on ceh growth and proliferation in myeloid leukemia cell lines

Objective To investigate the effects and mechanism of Wilms' tumor (WT1) an tisense oligonucleotides (AS-oligomers) on proliferation and apoptosis in m eyloid leukemia cell lines. Methods K562 and HL-60 cells were cultured in presence of WT1 oligomers. Bo th cell lines express WT1 gene with no p53 protein expression. Cells growth , apoptosis and expression of WT-1, bcl-2 genes were analysed using 3-[4,5- dimethylthiazol-2-yl]-2,5-diphenylmetrazolium bromide ( MTT) colorimetric a ssay, flow cytometry and reverse transcription-polymerase chain reaction (R T-PCR) methods. Results WT1 antisense oligonucleotides inhibited cellular proliferation of K562 cells and the effect was concentration-dependent. When cultured at. co ncentration of 200 mu g/ml oligomers, growth inhibition was 46.2% for antis ense oligonucleotide cultivated group and 28.1% for sense oligonucleotide c ultured group (P = 0.008) respectively. WT1 antisense oligonucleotide can i nduce apoptosis of K562 and HL-60 cells. Percentages of apoptotic cells in antisense oligonucleotide and sense oligonucleotide treated groups were 30. 88% versus 13.62% for K562 cells; and 40.15% versus 4.23% for HL-60 cells. However the growth of HL-60 cells and expression of bcl-2 gene were unaffec ted. Conclusions The WT1 gene is related with proliferation and apoptosis of leu kemic cells. Effect of anti-apoptosis may be independent of the cellular p5 3 status and bcl-2 expression. WT1 gene may play an important role in leuke mogenesis.