Paired related homoeobox1-induced breast cancer epithelial cell epithelial-mesenchymal transition to tamoxifen resistance

Abstract

Objective To investigate the effect of paired related homoeobox1 (Prrx1) on epithelial-mesenchymal transition (EMT) and the resistant ability to tamoxifen in breast cancer epithelial cells. Methods The Prrx1 low expression cell line MCF-7 cells were transfected by liposome transfection, experimental group were MCF-7 cells transfected with Prrx1 gene, blank control group was MCF-7 cells transfected with black vector, negative control group was MCF-7 cells and the transfection was verified by Western blotting. The expression level of Prrx1, E-cadherin and Vimentin was detected by real-time quantitative polymerase chain reaction (Real-time PCR). Cytotoxicity was detected by cell counting kit-8 (CCK-8) after exposure to tamoxifen. Results After MCF-7 cells were transfected with Prrx1, the fluorescence efficiency reached more than 80%. Western blotting results showed that the expression of Prrx1 in experimental group was significantly higher than in control groups (P=0.000), and there was no no statistically significant difference between two control groups (P=0.326). Real-time PCR results showed that the CT values of Prrx1 mRNA in negative control, blank control and experimental groups were 13.502±0.360, 13.770±0.642, 5.203±0.231 respectively. The Prrx1 mRNA expression level in the experimental group was 320 times that of the negative control group. The CT values of E-adherin mRNA in negative control, blank control and experimental groups were 18.471±0.076, 18.611±0.108, 19.394±0.400 respectively. The E-cad mRNA expression level in the experimental group was 0.560 times that of the negative control group. The CT values of vimentin mRNA in negative control, blank control and experimental groups were 19.422±0.082, 19.484±0.021, 17.817±0.061 respectively. The Vimentin mRNA expression level in the experimental group was 3.03 times that of the negative control group. CCK-8 results showed that after the action of tamoxifen, the half maximal inhibitory concentration (IC50) of experimental group was significantly higher than that in the two control groups (P=0.001), but there was no statistically significant difference between two control groups (P=0.150). Conclusion Prrx1 can enhance tamoxifen resistance of MCF-7 cells by inducing EMT. Key words: Breast cancer; Paired related homoeobox1; Epithelial-mesenchymal transition; Tamoxifen; Resistance