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Rac3 induces a molecular pathway triggering breast cancer cell aggressiveness: differences in MDA-MB-231 and MCF-7 breast cancer cell lines. BMC Cancer 2013; 13:63. [PMID: 23388133 PMCID: PMC3576359 DOI: 10.1186/1471-2407-13-63] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 01/30/2013] [Indexed: 12/19/2022] Open
Abstract
Background Rho GTPases are involved in cellular functions relevant to cancer. The roles of RhoA and Rac1 have already been established. However, the role of Rac3 in cancer aggressiveness is less well understood. Methods This work was conducted to analyze the implication of Rac3 in the aggressiveness of two breast cancer cell lines, MDA-MB-231 and MCF-7: both express Rac3, but MDA-MB-231 expresses more activated RhoA. The effect of Rac3 in cancer cells was also compared with its effect on the non-tumorigenic mammary epithelial cells MCF-10A. We analyzed the consequences of Rac3 depletion by anti-Rac3 siRNA. Results Firstly, we analyzed the effects of Rac3 depletion on the breast cancer cells’ aggressiveness. In the invasive MDA-MB-231 cells, Rac3 inhibition caused a marked reduction of both invasion (40%) and cell adhesion to collagen (84%), accompanied by an increase in TNF-induced apoptosis (72%). This indicates that Rac3 is involved in the cancer cells’ aggressiveness. Secondly, we investigated the effects of Rac3 inhibition on the expression and activation of related signaling molecules, including NF-κB and ERK. Cytokine secretion profiles were also analyzed. In the non-invasive MCF-7 line; Rac3 did not influence any of the parameters of aggressiveness. Conclusions This discrepancy between the effects of Rac3 knockdown in the two cell lines could be explained as follows: in the MDA-MB-231 line, the Rac3-dependent aggressiveness of the cancer cells is due to the Rac3/ERK-2/NF-κB signaling pathway, which is responsible for MMP-9, interleukin-6, -8 and GRO secretion, as well as the resistance to TNF-induced apoptosis, whereas in the MCF-7 line, this pathway is not functional because of the low expression of NF-κB subunits in these cells. Rac3 may be a potent target for inhibiting aggressive breast cancer.
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Bury L, Malara A, Gresele P, Balduini A. Outside-in signalling generated by a constitutively activated integrin αIIbβ3 impairs proplatelet formation in human megakaryocytes. PLoS One 2012; 7:e34449. [PMID: 22539947 PMCID: PMC3335122 DOI: 10.1371/journal.pone.0034449] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/02/2012] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The interaction of megakaryocytes with matrix proteins of the osteoblastic and vascular niche is essential for megakaryocyte maturation and proplatelet formation. Fibrinogen is present in the vascular niche and the fibrinogen receptor α(IIb)β(3) is abundantly expressed on megakaryocytes, however the role of the interaction between fibrinogen and α(IIb)β(3) in proplatelet formation in humans is not yet fully understood. We have recently reported a novel congenital macrothrombocytopenia associated with a heterozygous mutation of the β(3) subunit of α(IIb)β(3). The origin of thrombocytopenia in this condition remains unclear and this may represent an interesting natural model to get further insight into the role of the megakaryocyte fibrinogen receptor in megakaryopoiesis. METHODOLOGY/PRINCIPAL FINDINGS Patients' peripheral blood CD45+ cells in culture were differentiated into primary megakaryocytes and their maturation, spreading on different extracellular matrix proteins, and proplatelet formation were analyzed. Megakaryocyte maturation was normal but proplatelet formation was severely impaired, with tips decreased in number and larger in size than those of controls. Moreover, megakaryocyte spreading on fibrinogen was abnormal, with 50% of spread cells showing disordered actin distribution and more evident focal adhesion points than stress fibres. Integrin α(IIb)β(3) expression was reduced but the receptor was constitutively activated and a sustained, and substrate-independent, activation of proteins of the outside-in signalling was observed. In addition, platelet maturation from preplatelets was impaired. CONCLUSIONS/SIGNIFICANCE Our data show that constitutive activation of α(IIb)β(3)-mediated outside-in signalling in human megakaryocytes negatively influences proplatelet formation, leading to macrothombocytopenia.
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Affiliation(s)
- Loredana Bury
- Division of Internal and Cardiovascular Medicine, Department of Internal Medicine, University of Perugia, Perugia, Italy
- Biotechnology Laboratories, Department of Biochemistry, University of Pavia, IRCCS San Matteo Foundation, Pavia, Italy
| | - Alessandro Malara
- Division of Internal and Cardiovascular Medicine, Department of Internal Medicine, University of Perugia, Perugia, Italy
- Biotechnology Laboratories, Department of Biochemistry, University of Pavia, IRCCS San Matteo Foundation, Pavia, Italy
| | - Paolo Gresele
- Division of Internal and Cardiovascular Medicine, Department of Internal Medicine, University of Perugia, Perugia, Italy
| | - Alessandra Balduini
- Biotechnology Laboratories, Department of Biochemistry, University of Pavia, IRCCS San Matteo Foundation, Pavia, Italy
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Zhang C, Liu Y, Gao Y, Shen J, Zheng S, Wei M, Zeng X. Modified heparins inhibit integrin αIIbβ3mediated adhesion of melanoma cells to plateletsin vitroandin vivo. Int J Cancer 2009; 125:2058-65. [DOI: 10.1002/ijc.24561] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- ChunMei Zhang
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
| | - Yan Liu
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
| | - YanGuang Gao
- Department of Life Science and engineering, Harbin Institute of Technology, Harbin, China
| | - Jian Shen
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
| | - Sheng Zheng
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
| | - Min Wei
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
| | - XianLu Zeng
- Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China
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Van de Walle GR, Schoolmeester A, Iserbyt BF, Cosemans JMEM, Heemskerk JWM, Hoylaerts MF, Nurden A, Vanhoorelbeke K, Deckmyn H. Activation of αIIbβ3 is a sufficient but also an imperative prerequisite for activation of α2β1 on platelets. Blood 2006; 109:595-602. [PMID: 16985184 DOI: 10.1182/blood-2005-11-011775] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractPlatelet integrins α2β1 and αIIbβ3 play critical roles in platelet adhesion and thrombus formation after vascular injury. On resting platelets, both integrins are in a low-affinity state. However, agonist stimulation results in conformational changes that enable ligand binding that can be detected with conformation dependent monoclonal antibodies (mAbs). By using such conformation-dependent mAbs, we could demonstrate that activation of integrin αIIbβ3 is not only sufficient, but also a prerequisite for α2β1 activation. Compared with platelets in plasma, stimulation of washed platelets resulted in only a minor activation of α2β1, as detected with the activation-sensitive mAb IAC-1. Addition of fibrinogen to stimulated washed platelets greatly potentiated activation of this integrin. Also, treatment of αIIbβ3 with the ligand-mimetic peptide RGDS, resulting in outside-in signaling, led to a powerful α2β1 activation, even in the absence of overall platelet activation, involving tyrosine kinase activity but no protein kinase C activation. The absolute necessity of αIIbβ3 for proper α2β1 activation on platelets was demonstrated by using the αIIbβ3 antagonist aggrastat, which was able to completely abolish α2β1 activation, both under static and flow conditions. In addition, analogous experiments with Glanzmann platelets lacking αIIbβ3 confirmed the indispensability of αIIbβ3 for α2β1 activation.
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Affiliation(s)
- Gerlinde R Van de Walle
- Laboratory for Thrombosis Research, Katholieke Universiteit Leuven, KU Leuven Campus Kortrijk, E. Sabbelaan 53, B-8500 Kortrijk, Belgium, and Institut Fédératif No. 4, Hôpital Cardiologique, Pessac, France
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Legendre P, Salsmann A, Rayes J, Trassard O, Kieffer N, Baruch D. CHO cells expressing the high affinity alpha(IIb)beta3 T562N integrin demonstrate enhanced adhesion under shear. J Thromb Haemost 2006; 4:236-46. [PMID: 16409474 DOI: 10.1111/j.1538-7836.2005.01653.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Alpha(IIb)beta3-mediated platelet adhesive interactions in the vasculature, which are dependent on the functional state of this receptor, may be sensitive to shear forces. OBJECTIVES To evaluate the influence of the alpha(IIb)beta3 affinity state on cell attachment under flow, we compared Chinese hamster ovary cells expressing the low affinity alpha(IIb)beta3 wild-type (wt) receptor to those expressing the high affinity alpha(IIb)beta3 T562N receptor. MATERIALS AND METHODS We designed a real-time videomicroscopy adhesion assay for von Willebrand factor (VWF) or fibrinogen under flow conditions. RESULTS At 50 s(-1), alpha(IIb)beta3 T562N supported higher cell adhesion to fibrinogen (63.3 +/- 2.9 cells/field) than alpha(IIb)beta3 wt (38.7 +/- 2.4 cells/field, P < 0.0001). At 100 s(-1), alpha(IIb)beta3 T562N mediated cell adhesion (40.5 +/- 3.8 cells/field), while alpha(IIb)beta3 wt did not (5.3 +/- 1.4 cells/field, P < 0.001), allowing to discriminate the efficiency of each receptor. Similar findings were observed for adhesion to VWF. Complete inhibition of cell adhesion to fibrinogen was achieved with 800 microM fibrinogen gamma-chain dodecapeptide [HHLGGAKQAGDV (H12)], while Arg-Gly-Asp-Ser (RGDS) peptide (10-1000 microM) induced a dose-dependent cell detachment. These results suggest that the H12 motif allows initial attachment, in contrast to the RGDS site, which strengthens the stability of adhesion. Interestingly, compared with wt, a 10-fold lower concentration of RGDS was required to reach a similar reduction of cell adhesion mediated by alpha(IIb)beta3 T562N. CONCLUSIONS Our data show that alpha(IIb)beta3 activation is associated with a stabilization of integrin binding to fibrinogen or VWF under shear.
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Van de Walle GR, Vanhoorelbeke K, Majer Z, Illyés E, Baert J, Pareyn I, Deckmyn H. Two Functional Active Conformations of the Integrin α2β1, Depending on Activation Condition and Cell Type. J Biol Chem 2005; 280:36873-82. [PMID: 16103112 DOI: 10.1074/jbc.m508148200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For several integrins, the existence of multiple conformational states has been studied intensively. For the integrin alpha2beta1, a major collagen receptor on platelets and other cell types, however, no such experimental data were available thus far. Recently, our group has developed a monoclonal antibody IAC-1 sensitive to the molecular conformation of alpha2beta1 because it only binds to the activated state of alpha2beta1 on platelets, induced upon inside-out signaling. By investigating IAC-1 binding in combination with collagen binding after inside-out stimulation and outside manipulation, we demonstrated the existence of three different conformations of alpha2beta1 on platelets and Chinese hamster ovary cells as follows: (i) a nonactivated, resting state with no collagen nor IAC-1 binding; (ii) an intermediate state, induced by outside manipulation, with collagen but no IAC-1 binding; and (iii) a fully activated state, induced after inside-out stimulation, with both collagen and IAC-1 binding. Moreover, these different conformational states of alpha2beta1 are dependent on the cell type where alpha2beta1 is expressed, as IAC-1 binding to peripheral blood mononuclear cells and Jurkat cells could also be induced by outside manipulation, in contrast to platelets and alpha2beta1-expressing Chinese hamster ovary cells. Finally, we revealed a functional relevance for these different conformational states because the conformation of alpha2beta1, induced after outside manipulation, resulted in significantly more cell spreading on coated collagen compared with nonactivated or inside-out stimulated cells.
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Affiliation(s)
- Gerlinde R Van de Walle
- Laboratories for Thrombosis Research, Interdisciplinary Research Centre, Katholieke Universiteit Leuven, Campus Kortrijk, 8500 Kortrijk, Belgium
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Senis YA, Atkinson BT, Pearce AC, Wonerow P, Auger JM, Okkenhaug K, Pearce W, Vigorito E, Vanhaesebroeck B, Turner M, Watson SP. Role of the p110delta PI 3-kinase in integrin and ITAM receptor signalling in platelets. Platelets 2005; 16:191-202. [PMID: 16011964 PMCID: PMC1868960 DOI: 10.1080/09537100400016711] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We have investigated the function of the p110delta catalytic subunit of phosphoinositide 3-kinase (PI 3-kinase) in platelets using p110delta knock-out (p110delta(-/-)) mice and p110delta knock-in (p110delta(D910A/D910A)) mice, which express a catalytically inactive form of the enzyme. Aggregation to threshold concentrations of the GPVI-specific agonist, CRP, was partially reduced in p110delta(-/-) and p110delta(D910A/D910A) platelets. This inhibition was overcome by higher concentrations of CRP. The degree of inhibition was considerably weaker than that induced by LY294002 and wortmannin, which inhibit all isoforms of PI 3-kinase. p110delta(-/-) platelets showed decreased spreading on fibrinogen- or von Willebrand factor (VWF)-coated surfaces under static conditions, whereas they spread normally on collagen. LY294002 had a more pronounced inhibitory effect on spreading on all three surfaces. Adhesion and aggregate formation of p110delta(-/-) platelets to collagen or fibrinogen/VWF at intermediate/high rates of shear were normal. This study demonstrates a minor role for the p110delta catalytic subunit in mediating platelet activation by the collagen receptor GPVI and integrin alphaIIbeta3. The more pronounced inhibitory effect of LY294002 and wortmannin indicates that other isoforms of PI 3-kinase play a more significant role in signalling by the two platelet glycoprotein receptors.
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Affiliation(s)
- Yotis A Senis
- Centre for Cardiovascular Sciences, Division of Medical Sciences, Institute of Biomedical Research, Wolfson Drive, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK.
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Keuren JFW, Baruch D, Legendre P, Denis CV, Lenting PJ, Girma JP, Lindhout T. Von Willebrand factor C1C2 domain is involved in platelet adhesion to polymerized fibrin at high shear rate. Blood 2004; 103:1741-6. [PMID: 14604963 DOI: 10.1182/blood-2003-07-2267] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractFibrin is actively involved in platelet reactions essential for thrombus growth, in which von Willebrand factor (VWF) might be an important mediator. The aim of this study was to localize VWF domains that bind to fibrin and to determine their relevance in platelet adhesion. VWF binds specifically to fibrin with an apparent Kd of 2.2 μg/mL. Competition in the presence of 2 complementary fragments, SpIII (residues 1-1365) and SpII (residues 1366-2050), indicated that the high affinity binding site for fibrin is located in the C-terminal part, thus distinct from the A domains. Comparison of 2 deleted rVWF (ΔD4B-rVWF, ΔC1C2-rVWF) suggested that the C1C2 domains contained a fibrin binding site. This site is distinct from RGD, as shown by binding of D1746G-rVWF to fibrin. Perfusion studies at high shear rate demonstrated that C1C2 domains were required for optimal platelet adhesion to fibrin. With the use of a VWF-deficient mouse model, it was found that plasma VWF is critical for platelet tethering and adhesion to fibrin. These results suggest a dual role of fibrin-bound VWF in thrombus formation: first, fibrin-bound VWF is critical in the recruitment of platelets by way of glycoprotein (GP) Ib, and, second, it contributes to stationary platelet adhesion by way of binding to activated αIIbβ3.
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Affiliation(s)
- Jeffrey F W Keuren
- Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, The Netherlands
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