The role of CSF-1R on migration and invasion of canine mammary tumors

Abstract: The colony stimulating factor-1 receptor (CSF-1R) is a tyrosine kinase receptor expressed in mammary tumors of canines and breast carcinomas of humans. The expression of this receptor has been associated with increased invasion and migration in vitro. In breast cancer patients, expression of CSF-1R in the tumor tissue is associated with increased levels of lymph node metastasis. Epithelial cancer cells can secrete the ligand, colony stimulating factor-1(CSF-1). CSF-1 may cause autocrine stimulation of the receptor and attract and educate macrophages towards a tumor associated macrophage (TAM) phenotype. The CSF-1R is also important in the regulation of macrophages in organogenesis including mammary development. In this study, the expression of CSF-1R in CMT-U229 avl 2 cell line was examined using flow cytometry and immunohistochemistry. During flow cytometry the cells were sorted in two groups of CSF-1R positive cells and CSF-1R negative cells. The migration and invasion of the CSF-1R positive and CSF-1R negative 2 was evaluated using a wound healing assay and Matrigel invasion assay. The CMT-U229 avl 2 cells expressed CSF-1R in 93 % of the cells according to the result of the immunohistochemistry and in 21.4 % of the cells according to the result of the flow cytometry. The CSF-1R positive cells showed a slight increase in migration rate and a larger increase in invasion compared to the CSF-1R negative cells. In conclusion the CSF-1R was expressed in the CMT-U229 avl 2 cell line and this expression could be associated with invasiveness in the CMT-U229 avl 2 cell line.