Effect of Twist on proliferation and apoptosis of human brain glioma cells and underlying mechanism

Objective To investigate the effect of Twist on the growth and apoptosis of human brain glioma cells and the underlying mechanism. Methods Human glioma U251 cells were transfected with Twist small interfering RNA (siRNA) and siRNA control respectively. The expression levels of Twist mRNA and protein in transfected cells were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting respectively. The cell proliferation was measured by methyl thiazol tetrazolium (MTT) assay, apoptosis was examined by flow cytometry, and the levels of cleaved cysteinyl aspartate specific proteinase 3 (Cleaved Caspase-3), signal transducer and activators of transcription 3 (STAT3) and phosphorylated STAT3 (p-STAT3) proteins were detected by Western blotting. Results In U251 cells transfected with siRNA control, the cell proliferation activity (0.97±0.12, P=0.406), apoptosis rate [(11.92±1.10)%, P=0.788] and Cleaved Caspase-3 (0.23±0.06, P=0.198), STAT3 (0.96±0.12, P=0.165), p-STAT3 (0.15±0.05, P=0.890) and Twist levels in the cells (for mRNA and protein: 0.98±0.07 and 0.86±0.06; P=0.152, 0.671) showed no significant change as compared with the U251 cells without transfection. In U251 cells transfected with Twist siRNA, cell proliferation activity (0.62±0.05, P=0.004) and p-STAT3 levels (0.05±0.01, P=0.010) were decreased, the apoptosis rate [(45.62±4.36)%, P=0.000] and the level of Cleaved Caspase-3 (0.84±0.07, P=0.001) increased as compared with U251 cells without transfection. Conclusion After down-regulation of Twist, the proliferation of human glioma cells decreased and apoptosis increased, which might be related to the inhibition of STAT3 phosphorylation. Key words: Glioma; Signal transducer and activators of transcription 3; Twist; Apoptosis; Proliferation