title: Up-regulation of CXCR4 expression in PC-3 cells by stromal-derived factor-1alpha (CXCL12) increases endothelial adhesion and transendothelial migration: role of MEK/ERK signaling pathway-dependent NF-kappaB activation.
abstract: The chemokine stromal-derived factor-1alpha (SDF-1alpha/CXCL-12) and its receptor, CXCR4, play a crucial role in adhesion and transendothelium migration (TEM) of prostate cancer cells. We tested the hypothesis that enhanced expression of CXCR4 in prostate cancer cells is dependent upon SDF-1alpha-mediated activation of nuclear factor-kappaB (NF-kappaB). SDF-1alpha increased the CXCR4 mRNA and protein expression in PC-3 cells but not in LNCaP cells. Similarly, SDF-1alpha enhanced the NF-kappaB-dependent transcriptional activity in PC-3 cells but not in LNCaP cells. SDF-1alpha increased PC-3 cell adhesion to the human umbilical vein endothelial cell monolayer and enhanced TEM, which was abrogated with anti-CXCR4 monoclonal antibody (mAb). Suppression of NF-kappaB activity in PC-3 cells by a mutant IkappaBalpha super-repressor adenoviral vector decreased the CXCR4 mRNA expression and inhibited adhesion and TEM. Transient overexpression of p65 subunit of NF-kappaB in PC-3 cells up-regulated CXCR4 receptor expression and increased the adhesion and TEM of these cells in response to SDF-1alpha gradient. Treatment of PC-3 cells with SDF-1alpha leads to nuclear translocation of NF-kappaB protein within 15 to 30 minutes, which correlated with IkappaBalpha phosphorylation. A p42/44 mitogen-activated protein kinase [MAPK, extracellular signal regulated kinase-1/2 (ERK-1/2)] biphasic activation pattern was observed in these cells at 15 minutes and 3 hours after SDF-1alpha treatment. Phosphorylation of IkappaB kinase alpha was observed within 30 minutes, which was blocked by PD98059 [MAPK kinase (MEK) inhibitor]. PD98059 cotreatment significantly inhibited SDF-1alpha-induced NF-kappaB reporter activity and CXCR4 receptor expression as shown by flow cytometry. These data suggest that SDF-1alpha-induced expression of CXCR4 in PC-3 cells is dependent on MEK/ERK signaling cascade and NF-kappaB activation.
authors.affiliation: Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
authors.forename: Promil
authors.initials: P
authors.lastname: Kukreja
authors.forename: Asim B
authors.initials: AB
authors.lastname: Abdel-Mageed
authors.forename: Debasis
authors.initials: D
authors.lastname: Mondal
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Krishna C
authors.initials: KC
authors.lastname: Agrawal
mesh_terms: D001859:Bone Neoplasms / Q000556:secondary; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism / Q000494:pharmacology*; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D019718:Receptors, CXCR4 / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000096:biosynthesis / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D020672:I-kappa B Proteins; D016328:NF-kappa B; D019718:Receptors, CXCR4; D011994:Recombinant Proteins; D051996:Transcription Factor RelA