[Abnormal WT1 gene expression in paroxysmal nocturnal hemoglobinuria].

Objective: To explore the pathogenesis of abnormal WT1 expression in paroxysmal nocturnal hemoglobinuria (PNH).

Methods: The expression of WT1 mRNA in CD59⁻ and CD59⁺ bone marrow mononuclear cells (BMMNC) were measured by semi-quantitative reverse transcription PCR. After WT1 gene silence by RNA interference (RNAi) technology, biological characteristics of BMMNC were investigated by flow cytometry.

Results: The relative expression of WT1 mRNA in PNH CD59⁻ BMMNC (1.06 ± 0.12) was significantly higher than that in PNH CD59⁺ BMMNC (0.90 ± 0.12) and normal BMMNC (0.86 ± 0.05, P<0.05), but there was no significant difference between PNH CD59⁺ BMMNC and normal BMMNC (P>0.05). WT1 mRNA expression in PNH was positively correlated with the proportion of CD59⁻ cells (r²=0.490, P=0.016), but had no relationship with the proportion of CD59⁺ cells. After WT1 gene silence by siRNA in PNH CD59⁻ BMMNC, WT1 mRNA expression was decreased. The proportions of G0/G1 phase in PNH CD59⁻ cell blank control group and siRNA-scr transfected group were (92.73 ± 3.71)% and (93.06 ± 4.14)%, and the proportions of S phase were (6.99 ± 3.61)% and (6.73 ± 4.08)%, respectively. The proportions of G0/G1 and S phase in siRNA-WT1 transfected group was (94.46 ± 3.71)% and (5.40 ± 3.55)%, respectively. There were significant differences in the proportions of G0/G1 phase and S phase among the controls, siRNA-WT1 transfected group and siRNA-scr transfected group (P<0.05). The rate of apoptosis in siRNA-WT1 transfected group [(35.91 ± 22.36)%] was significantly higher than those in controls [(26.12 ± 17.10)%] and siRNA-scr transfected group [(27.39 ± 18.99)%] (P<0.05).

Conclusion: siRNA-WT1 could effectively suppress the WT1 gene expression of CD59⁻ clone in PNH patients, inhibit its proliferation, and promote its apoptosis. WT1 gene expression might contribute to PNH clone proliferation.