Quinaldic acid induces changes in the expression of p53 tumor suppressor both on protein and gene level in colon cancer LS180 cells.

BACKGROUND: Origin, synthesis and activity of quinaldic acid (QA), proposed derivative of kynurenic acid, have been poorly studied to date. Previously, we have demonstrated the antiproliferative effect of QA in a colon cancer model in vitro. The goal of present study was to verify QA activity to modify the expression of p53 tumor suppressor in colon cancer cells, and to relate it to its cancer cell growth inhibiting activity in vitro.

METHODS: LS180 colon cancer cells possessing the wild type form of p53 were used in the study. Real-time PCR and immunobloting techniques were used to test the expression of p53 at gene and protein level, respectively. Next, immunocytochemistry was used to visualize the localization of p53 protein within the cells. Furthermore, the antiproliferative activity of QA was retested in cells with siRNA silenced P53 gene.

RESULTS: The activity of QA to modify both the expression and phosphorylation of p53 protein as well as the level of P53 gene is shown. Concomitantly, the nuclear and cytoplasmic localization of phospho-p53 protein upon QA treatment is also presented. Moreover, reduced activity of QA in colon cancer cells with silenced p53 expression is observed.

CONCLUSION: QA affects the expression of p53 tumor suppressor, both at gene and protein level. The prominent contribution of p53 to the antiproliferative effect of QA in LS180 colon cancer cells can be suggested.