Effect and mechanism of lentivirus-mediated silencing of TPX2 gene on proliferation and apoptosis of human hepatoma cells.

Abstract

This study aimed to investigate the role and mechanism of action of targeting protein for Xklp2 (TPX2) in liver cancer, we compared TPX messenger RNA (mRNA) expression in liver cancer tissue samples and adjacent normal liver tissue samples as well as in human liver cancer cell lines and nonmalignant cell line by quantitative reverse transcription polymerase chain reaction (qRT-PCR). TPX2 gene was silenced in HepG2 cells by transfection with the lentiviral vector expressing TPX2-targeting short hairpin RNA (shRNA), and the knockdown efficiency was evaluated by RT-qPCR. Cell proliferation, apoptosis as well as protein level of c-Myc, cyclin D1, caspase-3, phosphorylated glycogen synthase kinase-3β (p-GSK-3β), and β-catenin in HepG2 cells were evaluated before and after the TPX2 knockdown. Wnt/β-catenin signaling pathway was inhibited by treatment with 20 μM of XAV-939 or activated by treatment with 20 mM of LiCl. We found that TPX2 mRNA level was significantly increased in liver cancer tissue samples and cell lines comparing to noncancerous counterparts (P < 0.05). TPX2 knockdown significantly reduces TPX2 expression (P < 0.01), cell proliferation (P < 0.05), protein level of c-Myc and cyclin D1 (P < 0.01), activation of Wnt/β-catenin signaling in HepG2 cells (P < 0.01) while increasing cell apoptosis (P < 0.01). Treatment with XAV-939 significantly reduced HepG2 cell proliferation (P < 0.05) while increasing cell apoptosis (P < 0.01). Treatment with LiCl significantly attenuated the antiproliferative and apoptosis-promoting effect of TPX2 knockdown on HepG2 cells (P < 0.05). Lentivirus-mediated silencing of TPX2 gene could inhibit proliferation and induce apoptosis in hepatoma cells by inhibiting Wnt signaling pathway and regulating cyclin and apoptosis-related proteins.