PPARγ suppressed Wnt/β-catenin signaling pathway and its downstream effector SOX9 expression in gastric cancer cells

Wnt signaling pathway activation plays a critical role in biological processes of tumor progression. SOX9 belongs to the sry-related high-mobility group box (SOX) family and is a key transcription factor in the development and differentiation of multiple cell lineages. The purpose of this study was to investigate whether suppression of Wnt signaling pathway by PPARγ gene affects target SOX9 gene expression. The pEGFP-N1-PPARγ overexpression recombinant plasmid was structured by molecular biology technology. The overexpression plasmid and empty vector pEGFP-N1 were transfected into three types of human gastric cancer cell lines, with different levels of differentiation, MKN-28, SGC-7901 and BGC-823. The PPARγ, β-catenin and SOX9 mRNA levels and proteins were examined by real-time PCR and Western blot analysis. The pEGFP-N1-PPARγ recombinant plasmid was constructed and transfected into MKN-28, SGC-7901 and BGC-823 successfully. High expression of PPARγ (p < 0.05) for transfection recombinant plasmid group induced obviously decreased expression of β-catenin (p < 0.05), whereas SOX9 expression decreased significantly (p < 0.05) compared with the transfection empty vector group and normal comparison group. PPARγ can suppress β-catenin expression in Wnt signaling pathway and its downstream effector SOX9 expression in gastric cancer cells.