title: Melanoma upregulates ICAM-1 expression on endothelial cells through engagement of tumor CD44 with endothelial E-selectin and activation of a PKCα-p38-SP-1 pathway.
abstract: Cancer metastasis involves multistep adhesive interactions between tumor cells (TCs) and endothelial cells (ECs), but the molecular mechanisms of intercellular communication in the tumor microenvironment remain elusive. Using static and flow coculture systems in conjunction with flow cytometry, we discovered that certain receptors on the ECs are upregulated on melanoma cell adhesion. Direct contact but not separate coculture between human umbilical endothelial cells (HUVECs) and a human melanoma cell line (Lu1205) increased intercellular adhesion molecule 1 (ICAM-1) and E-selectin expression on HUVECs by 3- and 1.5-fold, respectively, compared with HUVECs alone. The nonmetastatic cell line WM35 failed to promote ICAM-1 expression changes in HUVECs on contact. Enzyme-linked immunosorbent assay (ELISA) revealed that EC-TC contact has a synergistic effect on the expression of the cytokines interleukin (IL)-8, IL-6, and growth-related oncogene α (Gro-α). By using E-selectin cross-linking and beads coated with CD44 immunopurified from Lu1205 cells, we showed that CD44/selectin ligation was responsible for the ICAM-1 up-regulation on HUVECs. Protein kinase Cα (PKC-α) activation was found to be the downstream target of the CD44/selectin-initiated signaling, as ICAM-1 elevation was inhibited by siRNA targeting PKCα or a dominant negative form of PKCα (PKCα DN). Western blot analysis and electrophoretic mobility shift assays (EMSAs) showed that TC-EC contact mediated p38 phosphorylation and binding of the transcription factor SP-1 to its regulation site. In conclusion, CD44/selectin binding signals ICAM-1 up-regulation on the EC surface through a PKCα-p38-SP-1 pathway, which further enhances melanoma cell adhesion to ECs during metastasis.
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Pu
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Goodrich
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Changliang
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA cxd23@psu.edu.
authors.forename: Cheng
authors.initials: C
authors.lastname: Dong
mesh_terms: D002450:Cell Communication; D002460:Cell Line; D002478:Cells, Cultured; D019040:E-Selectin / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: C497483:CD44 protein, human; D019040:E-Selectin; D018960:Hyaluronan Receptors; D016329:Sp1 Transcription Factor; D018799:Intercellular Adhesion Molecule-1; D051571:Protein Kinase C-alpha; D048051:p38 Mitogen-Activated Protein Kinases
keywords: adhesion; cross-linking; cytokine; flow coculture; intracellular signaling