OBJECTIVE - To study p53, mdm-2 and p21WAF1 protein expression levels in ER-positive and ER-negative human breast cancer cell lines and their relations to biological features.
METHODS - Using cell culture, DNA stable transfection and immunohistochemical methods, the protein expression levels of p53, mdm-2 and WAF1 genes in ER-positive expressing wtp53 MCF-7 cells, ER-negative expressing mtp53 MDA-MB-231 cells and ER-transfected MDA-MB-231 cells were determined, and then, their relation to biological features were compared.
RESULTS - (1) The function and expression of p53 protein of MCF-7 and MDA-MB-231 cells were obviously different. The expression levels of mdm-2 and p21WAF1 proteins in MCF-7 cells were higher than those of MDA-MB-231 cells (P < 0.05), The biological features of the former were more favorable than those of the latter. (2) The ER-transfected MDA-MB-231 cells showed lower expression of mtp53 and higher expression of mdm-2 protein (P < 0.05), but no significant difference from that of p21WAF1 protein (P > 0.05). Meanwhile, biological features leading to favorable prognosis were manifested.
CONCLUSION - The ER status of breast cancer cell lines is related to the expression level of p53 and mdm-2 proteins and the biological features.