title: Involvement of the chemokine receptor CXCR4 and its ligand stromal cell-derived factor 1alpha in breast cancer cell migration through human brain microvascular endothelial cells.
abstract: In this study, we have characterized the signaling pathways mediated by CXCR4 in breast cancer cells and its role in breast cancer cell invasion and migration. Stromal cell-derived factor 1alpha (SDF-1alpha; CXCL12) stimulation of breast cancer cells resulted in phosphoinositide 3-kinase (PI-3K) activation, AKT phosphorylation, and activation of the FKHRL1 transcription factor. In addition, SDF-1alpha induced activation of the focal adhesion kinase (FAK) as well as the migration of breast cancer cells. Expression of SDF-1alpha, the ligand of CXCR4, was about 2-fold higher in microdissected human breast epithelial cancer cells as compared with normal epithelial cells. Immunohistochemical analysis indicated that SDF-1alpha expression is consistently higher in primary breast tumor cells than in normal breast epithelial cells. Furthermore, SDF-1alpha induced blood vessel instability, through increased vascular permeability, resulting in the penetration of breast tumor cells through the human brain microvascular endothelial cells (HBMEC). Notably, the migration of breast cancer cells was inhibited by the PI-3K inhibitor, Wortmannin, and the Ca(2+) inhibitor BAPTA/AM, indicating that transendothelial breast cancer cell migration induced by SDF-1alpha is mediated by activation of the PI-3K/AKT pathway and Ca(2+)-mediated signaling. Blockade of the CXCR4/SDF1 signaling pathway with anti-CXCR4 antibody also decreased transendothelial breast cancer cell migration as well as vascular permeability. This study focuses on novel interactions between highly relevant signaling pathways in breast cancer cells and brain microvascular endothelial cells and may provide insights into the molecular mechanisms of CXCR4/SDF-1alpha-mediated breast cancer metastasis to the brain.
authors.affiliation: Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, 4 Blackfan Circle, Boston, MA 02115, USA.
authors.forename: Byeong-Chel
authors.initials: BC
authors.lastname: Lee
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Lee
authors.forename: Shalom
authors.initials: S
authors.lastname: Avraham
authors.forename: Hava Karsenty
authors.initials: HK
authors.lastname: Avraham
mesh_terms: D001921:Brain / Q000098:blood supply*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology*; D004789:Enzyme Activation / Q000187:drug effects; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D006801:Humans; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019718:Receptors, CXCR4 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D002118:Calcium; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D004268:DNA-Binding Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019718:Receptors, CXCR4; D014157:Transcription Factors; C515255:CXCL12 protein, human; C085126:FOXO1 protein, human; C499517:FOXO3 protein, human; C496050:PTK2 protein, human; C494918:AKT1 protein, human