Experimental Study Of The Expression Of Chemokine Receptor CXCR4 In Colorectal Carcinomas Cell

Objective:To investigate the expression of chemokine receptor CXCR4 in the colorectal carcinomas cell lines and using chemotaxis assay for an exploration of metastasis mechanism and mechanism of CXCR4 expression in colorectal carcinomas; To observe the expression of CXCR4 and explore its regulation and control mechanism in colorectal carcinomas cell lines after being treated with EGF and SU11248 .Methods:1.Culture carcinomas cell lines HT29 and SW480,then detect the expression of CXCR4 receptor in these cell lines with immunohistochemistry and RT-PCR and Western-Blot.In vitro,chemotaxis chamber was used to test the chemotactic effect of SDF-1αon HT29 cells and SW480 cells; Anti-CXCR4 antibodies were used for inhibition studies.2.These serum-starved cell lines were treated with EGF and SU11248 each other, expression of CXCR4 was analyzed by immunohistochemistry and Western-Blot and RT-PCR method. Correlative signaling molecule was analyzed by Western-Blot .Results:1. Expression of CXCR4 was analyzed by immunohistochemistry, HT29 cells and SW480 cells which were in an exponential stage of growth can express CXCR4 . The positive expression rate of CXCR4 in HT29 cells and SW480 cells were 48.7% and 52.6% and stained intensity varyed from weak to strong .By RT-PCR method and Western-Blot method ,the positive expression of CXCR4 was determined also. Chemotaxis assay demonstrateed that the migration of carcinomas cells was induced by SDF-1 and the migration could be inhibit by an anti-CXCR4 antibody.In vitro,the migration number of the carcinomas cells which were treated with SDF-1 significantly higher as compared with the non-SDF-1 treated groups or the CXCR4 antibody treated groups . While the migration number of the non-SDF-1 treated groups compared with the CXCR4 antibody treated groups ,the data showed that they have statistically nonsignificant disparity. The CXCR4 antibody significantly impaired the migration of the colorectal carcinomas cells.2.The results of immunohistochemistry and Western-Blot suggested that EGF could enhance the expression of CXCR4 in these cell lines. The results also suggested that SU11248 could inhibit the expression of CXCR4 in these cell lines.Conclusion:(1) HT29 and SW480 cell lines could express chemokine receptor CXCR4.(2) The migration of carcinomas cells was induced by SDF-1 and the migration could be inhibit by an anti-CXCR4 antibody.(3) EGF could enhance the expression of CXCR4 and SU11248 could inhibit the expression of CXCR4 in these cell lines. Small molecule RTKs inhibitor that inhibits multiple receptor tyrosine kinases would benefit depressing metastasis of human colorectal carcinomas.