Duffy, Antigen Chemokine Receptor (darc) Inhibit The Growth And Lung Metastasis Of Human Breast Cancer Cells

Objective: To study effects of the Duffy antigen receptor for chemokines (DARC) on the tumorigenesis and the metasatasis potential of human breast cancer cells.Methods: Human DARC cDNA was reintroduced into the MDA-MB-231 cells and MDA-MB-435 cells with high capability of spontaneous pulmonary metastasis (MDA-MB-435HM) by stable transfection. Effects of DARC on the proliferation and invasion of the cells were investigated by MTT, flow cytometry and transwell. Human breast cancer cells were implanted orthotopically into BALB/c female nude mice. Tumor growth, pulmonary metastasis, intratumor CCL2 (MCP-1, JE) were tested, and MMP-9 in tumors were detected by Western blot, DARC and CD34 were detected by immunohistochemistry technology, and the relationship among them was analysized. Tissue sections from 75 breast cancer patients, 50.19±12.53 years old, grouped according to the local lymphonode status were examined immunohistochemically for protein expression of DARC. Microvessel density (MVD) was counted by endothelial cells immunostained using anti-CD34 antibody.Results: human DARC cDNA was reintroduced into the MDA-MB-231 and MDA-MB-435HM cells which have a high capability of spontaneous pulmonary metastasis. We demonstrated that DARC over-expression induced inhibition of tumorigenesis and/or metastasis through interfering with the tumor angiogenesis in vivo. This inhibition is associated with decreasing CCL2 protein levels, and MVD and MMP-9 expression in xenograft tumors. In human breast cancer samples, we also demonstrated that low expression of the DARC protein is significantly associated with estrogen receptor (ER) status, MVD, lymph node metastasis, distant metastasis and poor survival..Conclusions: DARC is a negative regulator of growth in breast cancer, mainly by sequestration of angioganic chemokines and subsequent inhibition of tumor neovascularity.