PBX1-promoted SFRP4 transcription inhibits cell proliferation and epithelial-mesenchymal transition in endometrial carcinoma.

OBJECTIVE:To explore the effects and mechanisms of action of the PBX1/secreted frizzled-related protein 4 (SFRP4) axis in endometrial carcinoma (EC). METHODS:The expression of PBX1 and SFRP4 was analyzed using bioinformatics prediction, followed by validation in EC cells using quantitative reverse transcription-polymerase chain reaction and western blotting. After transduction with overexpression vectors for PBX1 and SFRP4, migration, proliferation, and invasion of EC cells were measured, accompanied by the detection of E-cadherin, Snail, N-cadherin, Vimentin, β-catenin, GSK-3β, and C-myc expression. The association between PBX1 and SFRP4 was validated using dual luciferase reporter gene and chromatin immunoprecipitation assays. RESULTS:PBX1 and SFRP4 were downregulated in EC cells. Overexpression of PBX1 or SFRP4 resulted in weakened cell proliferation, migration, and invasion, as well as decreased expression of Snail, N-cadherin, Vimentin, β-catenin, GSK-3β, and C-myc and increased expression of E-cadherin. PBX1 bound to the SFRP4 promoter and promoted its transcription. Knockdown of SFRP4 reversed the repression of overexpressed PBX1 in the malignant phenotypes and EMT of EC cells, and PBX1 repressed Wnt/β-catenin pathway activation by upregulating SFRP4 transcription. CONCLUSION:PBX1 inhibited activation of the Wnt/β-catenin pathway by promoting SFRP4 transcription, thereby suppressing malignant phenotypes in EC cells and the EMT process.