Kaiso Interacts with p120-Catenin to Regulate β-Catenin Expression at the Transcriptional Level

BACKGROUND: We have reported that p120-catenin could regulate β-catenin transcription in lung cancer cells, but the specific mechanism is unclear. METHODS AND RESULTS: In this study, bisulfite sequencing PCR showed that the β-catenin promoter region in SPC-A-1 and LTEP-a-2 lung cancer cell lines has Kaiso binding sites sequences and CpG islands which may combine with Kaiso. The demethylating reagent 5-Aza-2′-deoxycytidine significantly upregulated β-catenin mRNA expression in lung cancer cell lines, whereas expression was significantly reduced following transfection with Kaiso. However, the upregulation of β-catenin mRNA expression after treatment with 5-Aza-2′-deoxycytidine was not reduced by subsequent transfection with Kaiso cDNA. Chromatin immunoprecipitation showed that, in lung cancer cell lines, methylated CpG-dinucleotides sequences combined with Kaiso and the Kaiso binding sites sequence did not. The capacity of Kaiso to combine with p120-catenin isoforms was confirmed by immunoprecipitation. CONCLUSIONS: Based on these results, we concluded that Kaiso participates in the regulation by p120ctn of β-catenin mRNA expression in the lung cancer cell lines.