[Effect of RNA Interference-silenced TAK1 on Kasumi-1 cell Proliferation Inhibition Induced by As 2 O 3 and Its Mechanism].

OBJECTIVE: To explore the effect of transforming growth factor-β activated kinase-1(TAK1) gene silenced by RNA interference on proliferation inhibition of Kasumi-1 cells induced by As2 O3 and its mechanism.

METHODS: The experiments were divided into 4 groups, including control group(Kasumi-1 cells treated with non-specific siRNA), TAK1 specific siRNA treated group (Kasumi 1 treated with TAK specific siRNA), As2 O3 treated group (Kasumi 1 cells treated with As2 O3 ) and combined treated group (Kasumi 1 cells treated with TAK1 specific siRNA plus As2 O3 ). The proliferation inhibition rate of Kasami 1 cells was detected by CCK-8 method, the apoptotic rate of cells was detected by flow eytometry, the expressions of TAK1, phosphorylated c-Jun N-terminal kinase(p-JNK) and apoptosis-related proteins were detected by Western blot.

RESULTS: As2 O3 could inhibit Kasumi-1 cell proliferation in a dose-dependent manner between 0.5 to 20 µmol/L with IC50 of (3.79±0.36) µmol/L at 24 h, and also inhibit Kasumi-1 cell proliferation in a dose-dependent manner between 0.5 to 10 µmol/L with IC50 of (2.38±0.17) µmol/L at 48 h, but then the inhibitory effect reached plateau. After treating Kasumi-1 cells with TAK1 siRNA and 3.5 µmol/L As2 O3 for 24 h, the proliferation inhibition rate was (10.86±1.64)% and (49.80±2.19)%, meanwhile the apoptosis rate was (8.47±0.75)% and (24.78±2.14)%, all significantly higher than those in control group (P<0.05, P<0.01). The proliferation inhibition rate and apoptosis rate of the combined treated group were significantly higher than that in control and single treated groups (P<0.05, P<0.01), TAK1 silencing and 3.5 µmol/L of As2 O3 could decrease the expression of TAK1, p-JNK, c-Fos, c-Jun and BCL-2 in different degrees, and increase the expression levels of BAX and the activated (cleaved) caspase-3, 9 with statistically significant differences as compared with control group (P< 0.05). When Kasumi-1 cells were treated with TAK1 specific siRNA plus As2 O3 for 24 h, protein expression levels were all significantly greater than that in the single-treated groups (P< 0.05).

CONCLUSION: TAK1 silencing and As2 O3 can separately and synergistically inhibit Kasumi-1 cell proliferation which probably relates with the inducing apoptosis via the JNK and mitochondrial pathway. Meanwhile, TAK1 silencing enhances the inhibitory effect of As2 O3 on Kasumi-1 cell proliferation.