Effect of Yes-associated Protein Knockdown on Apoptosis of Gastric Cancer BGC823 Cells Through Wnt/β-catenin Signaling Pathway

Objective To explore the effect of Yes-associated protein (YAP) on the apoptosis of gastric cancer BGC823 cells and related mechanism.

Methods YAP small interference RNA (YAP siRNA1, YAP siRNA2) were transfected into BGC823 cells. qRT-PCR and Western blot were used to determine the expression of YAP, respectively. YAP siRNA1, which had better interference effect, was selected for the follow-up experiment. MTT, plate clone formation assay and flow cytometry were applied to determine cells proliferation, cloning ability and apoptosis, respectively. The activities of Caspase-3 and Caspase-9 were detected by spectrophotometry. Western blot was applied to detect β-catenin, c-myc and CyclinD1 protein levels. BGC823 cells of down-regulated YAP were treated with Wnt/β-catenin activator. The cell proliferation, apoptosis and clonogenic ability were determined.

Results YAP siRNA1 and YAP siRNA2 downregulated the transcription and expression of YAP in BGC823 cells. The interference efficiency of YAP siRNA1 was better. After knocking down YAP, the abilities of cell proliferation and clone formation were decreased; the apoptosis rate was increased from (6.32±0.58)% to (32.71±2.64)%; the activities of Caspase-3 and Caspase-9 were increased; the expression of β-catenin, c-myc and cyclinD1 protein were decreased, with statistically significant difference compared with normal BGC823 cells (P < 0.05). The activator treatment of Wnt/β-catenin could partly reverse the effect of YAP knockdown on the apoptosis, proliferation, cloning formation of BGC823 cells and the activities of Caspase-3 and Caspase-9.

Conclusion YAP knockdown induces the apoptosis of gastric cancer cells, and the mechanism is related to the inhibition of Wnt/β-catenin pathway activation.