Abstract:
Objective To discuss the relationship between FoxQ1 and epidermal growth factor receptor (EGFR) gene expression in colorectal cancer, to provide basis for researching the mechanism of FoxQ1 gene in EGFR pathway. Methods The mRNA relative expression of FoxQ1 and EGFR genes in colorectal cancer cell lines 293-T were taken as reference. We detected the relative mRNA expression of FoxQ1 and EGFR genes in colorectal cancer cell lines DLD1, HT29, LOVO and HCT116. Real-time PCR was used to detect the mRNA relative expression of EGFR in DLD1 cells which was interfered by lentivirus (named DLD1-shRNA-FoxQ1); After DLD1-shRNA-FoxQ1 was processed by EGFR tyrosine kinase inhibitor Erlotinib HCl and siRNAEGFR, we detected the mRNA relative expression of FoxQ1 and EGFR genes by Real-time PCR. Results (1) Relative expression of FoxQ1 and EGFR in DLD1, HT29, LOVO, HCT116 were 83.09, 59.58, 0.06, 0.03 and 4.95, 3.67, 2.08, 1.36, respectively; (2) EGFR expression in DLD1 cells interfered by shRNA-FoxQ1 was increased with the decrease of FoxQ1 expression; (3) After the expression of EGFR in DLD1-shRNA-FoxQ1 and DLD1-shRNA-Control cells were inhibited by siRNA-EGFR, FoxQ1 expression was increased with the decrease of EGFR expression. When EGFR tyrosine kinase was blocked by Erlotinib HCl, FoxQ1 expression was increased. Conclusion FoxQ1 and EGFR gene expression trend are consistent in colorectal cancer cell lines. When FoxQ1 expression is inhibited in colorectal cancer, EGFR expression would be increased. While the expression or protein kinase activity of EGFR is inhibited, FoxQ1 expression would be increased. It is suggested that there may be a negative feedback regulation mechanism between FoxQ1 and EGFR gene expression, which could maintain the high expression of FoxQ1 and EGFR in colorectal cancer cells.