Kaiso suppresses β-catenin mRNA expression in cell lines that have not been treated with 5-Aza-CdR.
Lung cancer cell lines SPC (A) and LTE (E) were transfected with Kaiso cDNA plasmid. The effect of transfection at different time points was identified by Western blot. The Kaiso-specific band appears at 97 kDa. Statistical analysis of SPC (B) or LTE (F) by t-test showed a significant increase Kaiso expression in the cells transfected with Kaiso cDNA plasmid compared with the control cells (B: P = 0.003 for 24 h, P = 0.005 for 48 h, and P<0.001 for 96 h, respectively; F: P = 0.065 for 24 h, P = 0.007 for 48 h; P = 0.009 for 96 h, respectively). Analysis of β-catenin mRNA expression in SPC following treatment of using RT-PCR (C) and Real-Time PCR by ANOVA (D) showed that treatment with 5-Aza-CdR demethylation reagent (7 µmol/L) for 48 h resulted in significant upregulation (P = 0.007), whereas high Kaiso expression significantly down-regulated β-catenin mRNA expression (P = 0.004). The expression of β-catenin mRNA expression in cells treated with 5-Aza-CdR reagent did not change significantly in the presence of high Kaiso expression (P = 0.062). Similar effects were observed in the LTE cell line (G and H; H: P = 0.003, P = 0.001, and P = 0.055 accordingly).