Objective: To elucidate the effect of WT1 antisense oligonucleotide on and the role of WT1 gene in proliferation and apoptosis of leukemia cells.
Methods: K562, U937, HL-60 cell lines, leukemic blast from 8 acute myeloid leukemia patients and normal bone marrow cells from 8 healthy subjects were treated in vitro with WT1 antisense oligonucleotide (WT1 ASO) targeting to the translation site of WT1 mRNA. The inhibitory effect on growth of leukemia cells was measured by Trypan blue exclusion and colony-forming unit assay. Apoptosis was measured by flow cytometric analysis and DNA fragmentation assay.
Results: WT1 ASO significantly inhibited the proliferation of K562 cells expressing WT1 and leukemic blast of 4 in 8 acute myeloid leukemia patients, but didn't inhibit the growth of U937 cells which had no WT1 expression and CFU-GM of normal marrow cells from 8 healthy subjects. Whereas WT1 sense oligonucleotide (WT1 SO) had no effect on the proliferation of K562 cells, U937 cells and the CFU-GM of normal marrow cells. WT1 ASO could induce apoptosis of K562 cells and the level of apoptosis was increased markedly when combined with Vp16; WT1 ASO alone couldn't induce apoptosis of HL-60 cells, but could increase the apoptosis when combined with Vp16.
Conclusion: WT1 ASO specifically inhibit the growth of leukemic cells, induce apoptosis of K562 cells and increase the apoptosis susceptibility of leukemia cells to Vp16. WT1 plays an important role in proliferation and apoptosis of leukemic cells.