title: CXCL-12/stromal cell-derived factor-1alpha transactivates HER2-neu in breast cancer cells by a novel pathway involving Src kinase activation.
abstract: Experimental evidence suggests that CXCR4, a Gi protein-coupled receptor for the ligand CXCL12/stromal cell-derived factor-1alpha (SDF-1alpha), plays a role in breast cancer metastasis. Transactivation of HER2-neu by G protein-coupled receptor activation has been reported as a ligand-independent mechanism of activating tyrosine kinase receptors. We found that SDF-1alpha transactivated HER2-neu in the breast cancer cell lines MDA-MB-361 and SKBR3, which express both CXCR4 and HER2-neu. AMD3100, a CXCR4 inhibitor, PKI 166, an epidermal growth factor receptor/HER2-neu tyrosine kinase inhibitor, and PP2, a Src kinase inhibitor, each blocked SDF-1alpha-induced HER2-neu phosphorylation. Blocking Src kinase, with PP2 or using a kinase-inactive Src construct, and inhibiting epidermal growth factor receptor/HER2-neu signaling with PKI 166 each inhibited SDF-1alpha-stimulated cell migration. We report a novel mechanism of HER2-neu transactivation through SDF-1alpha stimulation of CXCR4 that involves Src kinase activation.
authors.affiliation: Department of Cancer Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Neslihan
authors.initials: N
authors.lastname: Cabioglu
authors.forename: Justin
authors.initials: J
authors.lastname: Summy
authors.forename: Claudia
authors.initials: C
authors.lastname: Miller
authors.forename: Nila U
authors.initials: NU
authors.lastname: Parikh
authors.forename: Aysegul A
authors.initials: AA
authors.lastname: Sahin
authors.forename: Sitki
authors.initials: S
authors.lastname: Tuzlali
authors.forename: Kevin
authors.initials: K
authors.lastname: Pumiglia
authors.forename: Gary E
authors.initials: GE
authors.lastname: Gallick
authors.forename: Janet E
authors.initials: JE
authors.lastname: Price
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004789:Enzyme Activation; D006801:Humans; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction; D015533:Transcriptional Activation; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D018719:Erb-b2 Receptor Tyrosine Kinases; D019061:src-Family Kinases; C515255:CXCL12 protein, human