title: Roles for GP IIb/IIIa and αvβ3 integrins in MDA-MB-231 cell invasion and shear flow-induced cancer cell mechanotransduction.
abstract: Adhesion of cancer cell to endothelial cells and the subsequent trans-endothelial migration are key steps in hematogenous metastasis. However, the molecular mechanisms of cancer cell/endothelial cell interaction under hemodynamic shear flow and how shear flow-induced cancer cell mechanotransduction are yet to be fully defined. In this study, we identified that the integrins of both platelet glycoprotein IIb/IIIa (GP IIb/IIIa) and αvβ3 were crucial for hematogenous metastasis of human breast carcinoma MDA-MB-231 cells. The cell migration and invasion were studied by using Millicell cell culture insert system. The numbers of invaded MDA-MB-231 cells significantly increased by thrombin-activated platelets and reduced by eptifibatide, a platelet inhibitor. Meanwhile, RGDWE peptides, a specific inhibitor of αvβ3 integrin, also inhibited MDA-MB-231 cell invasion. We further used a parallel-plate flow chamber to investigate MDA-MB-231 cell adhesion under flow conditions. Alike in static condition, the adhesion capability of MDA-MB-231 cells to endothelial monolayer was also significantly affected by GP IIb/IIIa and αvβ3 integrins. The expression of matrix metalloproteinase-2 (MMP-2), MMP-9 and αvβ3 integrin in MDA-MB-231 cells were up-regulated after low shear stress exposure (1.84 dynes/cm(2), 2 h). Moreover, we also demonstrated that low shear stress induced a sustained activation of p85 (a regulatory subunit of PI3K) and Akt. Pre-treating MDA-MB-231 cells with the specific PI3K inhibitor of LY294002 abolished the shear stress induced-Akt activation, and the expression of MMP-2, MMP-9, vascular endothelial growth factor (VEGF) and αvβ3 integrin were also down-regulated. Immunofluorescence assay showed that low shear stress also induced αvβ3 integrin clustering and nuclear factor-κB (NF-κB) activation. Interestingly, shear stress-induced activation of Akt and NF-κB was attenuated by LM609, a specific antibody of αvβ3 integrin. It suggests that αvβ3 integrin might be as a mechanosensor to trigger both PI3K/Akt and NF-κB signaling pathways. Taken together, these results establish that GP IIb/IIIa and αvβ3 integrins are essential mediators, and provide insight into how shear stress-induced αvβ3 integrin activation and the downstream pathways for contribution to MDA-MB-231 cell adhesion, migration and invasion.
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China.
authors.forename: Fenglong
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China.
authors.forename: Liuyuan
authors.initials: L
authors.lastname: Guan
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, PR China. Electronic address: liuyiyao@hotmail.com.
authors.forename: Yiyao
authors.initials: Y
authors.lastname: Liu
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D039564:Integrin alphaV / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D009361:Neoplasm Invasiveness; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D057705:Transendothelial and Transepithelial Migration / Q000502:physiology
chemical_list: D039564:Integrin alphaV; D019039:Platelet Glycoprotein GPIIb-IIIa Complex
keywords: Integrin; MDA-MB-231 cells; NF-κB; PI3K/Akt pathway; Shear stress