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Hsiao YH, Lien HC, Hwa HL, Kuo WH, Chang KJ, Hsieh FJ. SPARC (Osteonectin) in Breast Tumors of Different Histologic Types and Its Role in the Outcome of Invasive Ductal Carcinoma. Breast J 2010; 16:305-8. [DOI: 10.1111/j.1524-4741.2009.00899.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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53
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Chlenski A, Cohn SL. Modulation of matrix remodeling by SPARC in neoplastic progression. Semin Cell Dev Biol 2009; 21:55-65. [PMID: 19958839 DOI: 10.1016/j.semcdb.2009.11.018] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 11/20/2009] [Indexed: 01/10/2023]
Abstract
SPARC is a matricellular glycoprotein that mediates interactions between cells and their microenvironment. It is produced at sites of tissue remodeling, where it regulates matrix deposition and turnover, cell adhesion, and signaling by extracellular factors, exerting profound effects on tissue architecture and cell physiology. During extensive matrix remodeling in neoplastic progression, SPARC is expressed in cancer-associated stroma and in malignant cells of some types, affecting tumor development, invasion, metastases, angiogenesis and inflammation. SPARC-induced changes in the tumor microenvironment can suppress or promote progression of different cancers depending on the tissue and cell type. Understanding the mechanism of matrix remodeling and its regulation by SPARC is essential for the development of new treatment strategies for highly aggressive cancers.
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Affiliation(s)
- Alexandre Chlenski
- Department of Pediatrics, Section of Hematology/Oncology, University of Chicago, Chicago, IL 60637, United States.
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54
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Segat L, Milanese M, Pirulli D, Trevisiol C, Lupo F, Salizzoni M, Amoroso A, Crovella S. Secreted protein acidic and rich in cysteine (SPARC) gene polymorphism association with hepatocellular carcinoma in Italian patients. J Gastroenterol Hepatol 2009; 24:1840-6. [PMID: 19817957 DOI: 10.1111/j.1440-1746.2009.06009.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Hepatocellular carcinoma (HCC) is a multifactorial disease driven by both genetic and epigenetic factors. Infection, inflammation and the immune response against hepatitis B virus and hepatitis C virus have been shown to play an important role in increasing cancer risk and promoting tumor development. In order to investigate the genetic component influencing HCC development, we analyzed 50 single nucleotide polymorphisms (SNP) spanning 34 different genes in 230 Italian patients affected by HCC and 230 controls. METHODS Genes were selected on the basis of their known biological function and their possible involvement in the progression or in the susceptibility to HCC was considered. SNP genotyping was performed using allelic-specific fluorescent probes. RESULTS For most SNP, no differences were identified between HCC patients and controls, with the exception of rs2304052, localized on the secreted protein acidic and rich in cysteine (SPARC) gene, which was significantly associated to the disease. The C allele was significantly more frequent in the HCC patients than in the healthy controls (23% vs 10%, corrected P < 0.001), as well as the CC genotype (13% vs 1%, corrected P < 0.001). CONCLUSION Since the presence of the rs2304052 C allele is associated with an increased risk (odds ratio: 2.76) of developing hepatocarcinoma, our results allowed us to identify a SNP in the SPARC gene correlating to HCC susceptibility.
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Affiliation(s)
- Ludovica Segat
- Genetic Unit, IRCCS Burlo Garofolo and Department of Reproductive and Developmental Biology, University of Trieste, Trieste, Italy.
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55
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Arnold SA, Brekken RA. SPARC: a matricellular regulator of tumorigenesis. J Cell Commun Signal 2009; 3:255-73. [PMID: 19809893 PMCID: PMC2778590 DOI: 10.1007/s12079-009-0072-4] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 09/14/2009] [Indexed: 12/11/2022] Open
Abstract
Although many clinical studies have found a correlation of SPARC expression with malignant progression and patient survival, the mechanisms for SPARC function in tumorigenesis and metastasis remain elusive. The activity of SPARC is context- and cell-type-dependent, which is highlighted by the fact that SPARC has shown seemingly contradictory effects on tumor progression in both clinical correlative studies and in animal models. The capacity of SPARC to dictate tumorigenic phenotype has been attributed to its effects on the bioavailability and signaling of integrins and growth factors/chemokines. These molecular pathways contribute to many physiological events affecting malignant progression, including extracellular matrix remodeling, angiogenesis, immune modulation and metastasis. Given that SPARC is credited with such varied activities, this review presents a comprehensive account of the divergent effects of SPARC in human cancers and mouse models, as well as a description of the potential mechanisms by which SPARC mediates these effects. We aim to provide insight into how a matricellular protein such as SPARC might generate paradoxical, yet relevant, tumor outcomes in order to unify an apparently incongruent collection of scientific literature.
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Affiliation(s)
- Shanna A Arnold
- Hamon Center for Therapeutic Oncology Research, Division of Surgical Oncology and Departments of Surgery and Pharmacology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390-8593 USA
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56
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Said N, Frierson HF, Chernauskas D, Conaway M, Motamed K, Theodorescu D. The role of SPARC in the TRAMP model of prostate carcinogenesis and progression. Oncogene 2009; 28:3487-98. [PMID: 19597474 DOI: 10.1038/onc.2009.205] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
SPARC (Secreted Protein Acidic and Rich in Cysteine), is a matricellular glycoprotein that is produced by tumor and/or neighboring stroma. In human prostate cancer, SPARC immunoreactivity is highest in metastatic lesions but distinct contributions of tumoral and stromal SPARC to tumorigenesis and progression are unclear. To determine the role of SPARC in primary prostate tumorigenesis, we crossed SPARC-null (SP(-/-)) with TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice. TRAMP(+)/SP(-/-) mice exhibited accelerated cancer development and progression. Compared to their TRAMP(+)/SP(-/-) counterparts, TRAMP(+)/SP(+/+) tumors had fewer proliferating cells, and decreased cyclins A and D1 with increased p21(Cip) and p27(Kip). Similar effects on proliferation and cell-cycle regulators were observed in human prostate cancer cell lines, transiently transfected with pSPARC. TRAMP(+)/SP(-/-) tumors exhibited decreased stromal collagen, enhanced matrix metalloproteinase activity and increased vascular endothelial growth factor, proinflammatory cytokines. To determine the contribution of stromal SPARC, we evaluated subcutaneous tumor growth of TRAMP cell lines in syngeneic SP(+/+) and SP(-/-) mice. Enhanced growth, decreased stromal collagen and increased proteolysis were noted in SP(-/-) mice. Our findings demonstrate that both tumor and stromal SPARC are limiting for primary prostate tumorigenesis and progression, through effects on the cell cycle and the creation of a less favorable tumor microenvironment.
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Affiliation(s)
- N Said
- Department of Urology, University of Virginia, Charlottesville, VA 22908, USA
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57
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Aberrant promoter methylation of SPARC in ovarian cancer. Neoplasia 2009; 11:126-35. [PMID: 19177197 DOI: 10.1593/neo.81146] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 10/24/2008] [Accepted: 10/27/2008] [Indexed: 12/31/2022] Open
Abstract
Epigenetic silencing of tumor suppressor genes is a new focus of investigation in the generation and proliferation of carcinomas. Secreted protein acidic and rich in cysteine (SPARC) is reportedly detrimental to the growth of ovarian cancer cells and has been shown to be epigenetically silenced in several cancers. We hypothesized that SPARC is downregulated in ovarian cancer through aberrant promoter hypermethylation. To that end, we analyzed SPARC expression in ovarian cancer cell lines and investigated the methylation status of the Sparc promoter using methylation-specific polymerase chain reaction. Our results show that SPARC mRNA expression is decreased in three (33%) and absent in four (44%) of the nine ovarian cancer cell lines studied, which correlated with hypermethylation of the Sparc promoter. Treatment with the demethylating agent 5-aza-2'-deoxycytidine rescued SPARC mRNA and protein expression. Addition of exogenous SPARC, as well as ectopic expression by an adenoviral vector, resulted in decreased proliferation of ovarian cancer cell lines. Investigation of primary tumors revealed that the Sparc promoter is methylated in 68% of primary ovarian tumors and that the levels of SPARC protein decrease as the disease progresses from low to high grade. Lastly, de novo methylation of Sparc promoter was shown to be mediated by DNA methyltransferase 3a. These results implicate Sparc promoter methylation as an important factor in the genesis and survival of ovarian carcinomas and provide new insights into the potential use of SPARC as a novel biomarker and/or treatment modality for this disease.
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58
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Shelton L, Rada JAS. Inhibition of human scleral fibroblast cell attachment to collagen type I by TGFBIp. Invest Ophthalmol Vis Sci 2009; 50:3542-52. [PMID: 19387070 DOI: 10.1167/iovs.09-3460] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Transforming growth factor beta-induced protein (TGFBIp; 68 kDa) is a secreted extracellular matrix (ECM) protein that has been demonstrated to regulate cell attachment in a variety of cell types. The sclera synthesizes and secretes TGFBIp, which may function to facilitate scleral ECM remodeling events associated with myopia development. Here the authors report that human scleral fibroblasts (HSFs) express TGFBI and that its protein product, TGFBIp, mediates an effect on cell attachment. METHODS TGFBI/TGFBIp expression was evaluated by RT-PCR and immunoblot of HSF lysates and culture supernatants. The effect of rTGFBIp (50 microg/mL) on cell attachment to collagen type I was determined with the use of fluid-phase cell attachment assays in HSFs, human foreskin fibroblasts (HFFs), and human corneal stroma fibroblasts (HCFs). Binding assays using biotinylated rTGFBIp were used to assess TGFBIp binding to the HSF surface. Flow cytometry and immunocytochemistry were used to determine both alphavbeta3 and alphavbeta5 expression and localization to the HSF cell surface. RESULTS HSFs expressed TGFBI and secreted TGFBIp (approximately 833 ng/h). rTGFBIp significantly decreased (25 microg/mL; P <or= 0.05) HSF attachment to collagen type I, whereas rTGFBIp did not significantly affect cell attachment of HFFs (P = 0.50) or HCFs (P = 0.24) to collagen compared with BSA. Integrins alphavbeta3 and alphavbeta5 were detected on the cell surface, and both anti-alphavbeta3 and anti-alphavbeta5 functionally blocked rTGFBIp binding to HSFs. CONCLUSIONS TGFBIp plays an inhibitory role in HSF attachment to collagen type I in vitro through interactions with alphavbeta3 and alphavbeta5 integrin receptors. These results suggest that TGFBIp may modulate scleral cell-matrix interactions in vivo, thereby affecting scleral viscoelasticity.
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Affiliation(s)
- Lilian Shelton
- Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
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59
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Ksiazek K, Mikula-Pietrasik J, Korybalska K, Dworacki G, Jörres A, Witowski J. Senescent peritoneal mesothelial cells promote ovarian cancer cell adhesion: the role of oxidative stress-induced fibronectin. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:1230-40. [PMID: 19246646 DOI: 10.2353/ajpath.2009.080613] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Adhesion of ovarian cancer cells to the peritoneal mesothelium is a key step in the malignant progression of the disease. In an in vitro study, we showed that the adherence of ovarian cancer cells (of the OVCAR-3, SKOV-3, and A2780 cell lines) to senescent human omentum-derived peritoneal mesothelial cells (HOMCs) was greater than to early passage cells. The process was mediated primarily by the increased interaction of the alpha5beta1 integrin on cancer cells with HOMC-associated fibronectin (FN). In comparison with early passage HOMCs, senescent cells exhibited increased FN mRNA expression levels and produced significantly more FN. To assess the effect of senescence-associated oxidative stress on FN release, HOMCs were rendered senescent by exposure to an oxidant, tert-butyl hydroperoxide. Treatment with tert-butyl hydroperoxide resulted in a significant increase in HOMC FN mRNA and protein expression levels. The effect of oxidative stress on FN synthesis was found to be mediated by transforming growth factor-beta1, whose signaling pathway was controlled at upstream and downstream levels by p38 MAPK. The activity of p38 MAPK increased markedly in senescent HOMCs. Treatment of HOMCs with antioxidants significantly attenuated senescence-associated increases in p38 MAPK activity, production of both transforming growth factor-beta1 and FN, and ovarian cancer cell adhesion. These data indicate that oxidative stress that accompanies senescence may increase FN production by HOMCs and thus facilitate binding and dissemination of ovarian cancer cells.
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Affiliation(s)
- Krzysztof Ksiazek
- Department of Pathophysiology, Poznan University of Medical Sciences, Swiecickiego 6, 60-781 Poznan, Poland
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60
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Affiliation(s)
- Wafic M Elmasri
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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61
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Podhajcer OL, Benedetti LG, Girotti MR, Prada F, Salvatierra E, Llera AS. The role of the matricellular protein SPARC in the dynamic interaction between the tumor and the host. Cancer Metastasis Rev 2008; 27:691-705. [PMID: 18542844 DOI: 10.1007/s10555-008-9146-7] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Tumor growth is essentially the result of an evolving cross-talk between malignant and surrounding stromal cells (fibroblasts, endothelial cells and inflammatory cells). This heterogeneous mass of extracellular matrix and intermingled cells interact through cell-cell and cell-matrix contacts. Malignant cells also secrete soluble proteins that reach neighbor stromal cells, forcing them to provide the soil on which they will grow and metastasize. Different studies including expression array analysis identified the matricellular protein SPARC as a marker of poor prognosis in different cancer types. Further evidence demonstrated that high SPARC levels are often associated with the most aggressive and highly metastatic tumors. Here we describe the most recent evidence that links SPARC with human cancer progression, the controversy regarding its role in certain human cancers and the physiological processes in which SPARC is involved: epithelial-mesenchymal transition, immune surveillance and angiogenesis. Its relevance as a potential target in cancer therapy is also discussed.
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Affiliation(s)
- Osvaldo L Podhajcer
- Laboratory of Molecular and Cellular Therapy, Fundacion Instituto Leloir, University of Buenos Aires, National Council for Scientific and Technological Research (CONICET), Buenos Aires, Argentina.
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62
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Sangaletti S, Di Carlo E, Gariboldi S, Miotti S, Cappetti B, Parenza M, Rumio C, Brekken RA, Chiodoni C, Colombo MP. Macrophage-derived SPARC bridges tumor cell-extracellular matrix interactions toward metastasis. Cancer Res 2008; 68:9050-9. [PMID: 18974151 DOI: 10.1158/0008-5472.can-08-1327] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Other than genetic imprinting and epithelial to mesenchymal transition, cancer cells need interaction with the nearby stroma toward metastasis. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein known to regulate extracellular matrix (ECM) deposition and cell-ECM interaction. Gene expression profiles associate SPARC to malignant progression. Using reciprocal bone marrow chimeras between SPARC knockout and wild-type mice, we show that SPARC produced by inflammatory cells is necessary for spontaneous, but not experimental, i.v. metastasis. Macrophage-derived SPARC induces cancer cell migration and enhances their migration to other ECM proteins at least through alpha(v)beta(5) integrin. Indeed, RNA interference knockdown of beta(5) integrin expression reduces cell migration in vitro and metastasis in vivo. Together these results show that macrophage-derived SPARC takes part in metastasis, acting at the step of integrin-mediated migration of invasive cells.
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Affiliation(s)
- Sabina Sangaletti
- Department of Experimental Oncology, Immunotherapy and Gene Therapy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Nazionale dei Tumori, Universita degli Studi di Milano, Milan, Italy
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63
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Vincent AJ, Lau PW, Roskams AJ. SPARC is expressed by macroglia and microglia in the developing and mature nervous system. Dev Dyn 2008; 237:1449-62. [PMID: 18366138 DOI: 10.1002/dvdy.21495] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that is highly expressed during development, tissue remodeling, and repair. SPARC produced by olfactory ensheathing cells (OECs) can promote axon sprouting in vitro and in vivo. Here, we show that in the developing nervous system of the mouse, SPARC is expressed by radial glia, blood vessels, and other pial-derived structures during embryogenesis and postnatal development. The rostral migratory stream contains SPARC that becomes progressively restricted to the SVZ in adulthood. In the adult CNS, SPARC is enriched in specialized radial glial derivatives (Müller and Bergmann glia), microglia, and brainstem astrocytes. The peripheral glia, Schwann cells, and OECs express SPARC throughout development and in maturity, although it appears to be down-regulated with maturation. These data suggest that SPARC may be expressed by glia in a spatiotemporal manner consistent with a role in cell migration, neurogenesis, synaptic plasticity, and angiogenesis.
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Affiliation(s)
- Adele J Vincent
- Department of Zoology, University of British Columbia, Vancouver, Canada.
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64
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SPARC in cancer biology: its role in cancer progression and potential for therapy. Drug Resist Updat 2008; 11:231-46. [PMID: 18849185 DOI: 10.1016/j.drup.2008.08.005] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 02/06/2023]
Abstract
The ability to effectively target a tumor to achieve complete regression and cure is the ultimate goal that drives our need to better understand tumor biology. Recently, SPARC has generated considerable interest as a multi-faceted protein that belongs to a family of matricellular proteins. It functions not only to modulate cell-cell and cell-matrix interactions, but its de-adhesive and growth inhibitory properties in non-transformed cells have led to studies to assess its role in cancer. Its divergent actions reflect the complexity of this protein, because in certain types of cancers, such as melanomas and gliomas, SPARC is associated with a highly aggressive tumor phenotype, while in others, mainly ovarian, neuroblastomas and colorectal cancers, SPARC may function as a tumor suppressor. Recent studies have also demonstrated a role for SPARC in sensitizing therapy-resistant cancers. Here, the role of SPARC in cancer progression and its potential application in cancer therapy is discussed.
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65
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Said NA, Elmarakby AA, Imig JD, Fulton DJ, Motamed K. SPARC ameliorates ovarian cancer-associated inflammation. Neoplasia 2008; 10:1092-104. [PMID: 18813349 PMCID: PMC2546586 DOI: 10.1593/neo.08672] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 07/06/2008] [Accepted: 07/08/2008] [Indexed: 02/04/2023]
Abstract
We have recently identified that the role of secreted protein acidic and rich in cysteine (SPARC) in amelioration of peritoneal ovarian carcinomatosis is mediated, at least in part, through mesothelial cell/lysophosphatidic acid-induced inflammatory response in ovarian cancer cells. The aim of this study was to elucidate the molecular mechanisms of the interactions between tumor cells and the cellular components of the ovarian cancer peritoneal microenvironment, specifically, mesothelial cells and macrophages. We found that SPARC not only significantly reduced macrophage chemoattractant protein-1 production and its macrophage chemotactic effect, but also attenuated the response of ovarian cancer cells to the mitogenic and proinvasive effects of macrophage chemo-attractant protein-1 and decreased macrophage-induced cancer cell invasiveness. Overexpression of SPARC in ovarian cancer cells significantly attenuated macrophage- and mesothelial cell-induced production and activity of interleukin-6, prostanoids (prostaglandins E2 and 8-isoprostanes) as well as matrix metalloproteinases and urokinase plasminogen activator. Moreover, the effects of SPARC overexpression in ovarian cancer cells were mediated, in part, through inhibition of nuclear factor-kappaB promoter activation. These results indicate, for the first time, that the effects of tumor SPARC as a negative regulator of ovarian cancer are mediated through decreased recruitment of macrophages and downregulation of the associated inflammation.
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Affiliation(s)
- Neveen A Said
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
| | - Ahmed A Elmarakby
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
| | - John D Imig
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
- Department of Physiology, Medical College of Georgia, Augusta, GA, USA
| | - David J Fulton
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
- Department of Pharmacology, Medical College of Georgia, Augusta, GA, USA
| | - Kouros Motamed
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
- Department of Pathology, Medical College of Georgia, Augusta, GA, USA
- Abraxis BioScience, Marina del Rey, CA, USA
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66
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Podhajcer OL, Benedetti L, Girotti MR, Prada F, Salvatierra E, Llera AS. The role of the matricellular protein SPARC in the dynamic interaction between the tumor and the host. Cancer Metastasis Rev 2008; 27:523-37. [PMID: 18459035 DOI: 10.1007/s10555-008-9135-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Tumor growth is essentially the result of an evolving cross-talk between malignant and surrounding stromal cells (fibroblasts, endothelial cells and inflammatory cells). This heterogeneous mass of extracellular matrix and intermingled cells interact through cell-cell and cell-matrix contacts. Malignant cells also secrete soluble proteins that reach neighbor stromal cells, forcing them to provide the soil on which they will grow and metastasize. Different studies including expression array analysis identified the matricellular protein SPARC as a marker of poor prognosis in different cancer types. Further evidence demonstrated that high SPARC levels are often associated with the most aggressive and highly metastatic tumors. Here we describe the most recent evidence that links SPARC with human cancer progression, the controversy regarding its role in certain human cancers and the physiological processes in which SPARC is involved: epithelial-mesenchymal transition, immune surveillance and angiogenesis. Its relevance as a potential target in cancer therapy is also discussed.
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Affiliation(s)
- Osvaldo L Podhajcer
- Laboratory of Molecular and Cellular Therapy, Fundacion Instituto Leloir, University of Buenos Aires, National Council for Scientific and Technological Research (CONICET), Buenos Aires, Argentina.
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67
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Nie J, Chang B, Traktuev DO, Sun J, March K, Chan L, Sage EH, Pasqualini R, Arap W, Kolonin MG. IFATS collection: Combinatorial peptides identify alpha5beta1 integrin as a receptor for the matricellular protein SPARC on adipose stromal cells. Stem Cells 2008; 26:2735-45. [PMID: 18583538 DOI: 10.1634/stemcells.2008-0212] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The biological features of adipose stromal (stem) cells (ASC), which serve as progenitors for differentiated cells of white adipose tissue (WAT), are still largely undefined. In an initiative to identify functional ASC surface receptors, we screened a combinatorial library for peptide ligands binding to patient-derived ASC. We demonstrate that both primary and cultured human and mouse stromal cells express a conserved receptor targeted by peptides found to mimic SPARC, a matricellular protein that is required for normal WAT development. A signaling receptor for SPARC has not as yet been determined. By using the SPARC-mimicking peptides CMLAGWIPC (termed hPep) and CWLGEWLGC (termed mPep), isolated by panning on human and mouse cells, respectively, we identified the alpha5beta1 integrin complex as a candidate receptor for SPARC. On the basis of these results, we evaluated ASC responses to SPARC or SPARC-mimicking peptide exposure. Our results suggest that extracellular SPARC binds to alpha5beta1 integrin at sites of focal adhesions, an interaction disrupting firm attachment of ASC to extracellular matrix. We propose that SPARC-mediated mobilization of ASC through its effect on alpha5beta1 integrin complex provides a functional basis for the regulation of WAT body composition by SPARC. We also show that alpha5beta1 integrin is a potential target for ASC-selective intracellular delivery of bioactive peptides and gene therapy vectors directed by the SPARC-mimicking peptides. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Jing Nie
- Hope Heart Program, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
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68
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Said N, Socha MJ, Olearczyk JJ, Elmarakby AA, Imig JD, Motamed K. Normalization of the ovarian cancer microenvironment by SPARC. Mol Cancer Res 2007; 5:1015-30. [PMID: 17951402 DOI: 10.1158/1541-7786.mcr-07-0001] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Malignant ascites is a major source of morbidity and mortality in ovarian cancer patients. It functions as a permissive reactive tumor-host microenvironment and provides sustenance for the floating tumor cells through a plethora of survival/metastasis-associated molecules. Using a syngeneic, immunocompetent model of peritoneal ovarian carcinomatosis in SP(-/-) mice, we investigated the molecular mechanisms implicated in the interplay between host secreted protein acidic and rich in cysteine (SPARC) and ascitic fluid prosurvival/prometastasis factors that result in the significantly augmented levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP). Ascitic fluid-enhanced ID8 invasiveness was mediated through VEGF via a positive feedback loop with MMP-2 and MMP-9 and through activation of alpha(v) and beta(1) integrins. Host SPARC down-regulated the VEGF-MMP axis at the transcriptional and posttranscriptional levels. In vitro, SPARC attenuated the basal as well as VEGF-induced integrin activation in tumor cells. SPARC inhibited the VEGF- and integrin-mediated ID8 proliferation in vitro and significantly suppressed their tumorigenicity in vivo. Relative to SP(+/+), SP(-/-) ascitic fluid contained significantly higher levels of bioactive lipids and exerted stronger chemotactic, proinvasive, and mitogenic effects on ID8 cells in vitro. SP(-/-) ascites also contained high levels of interleukin-6, macrophage chemoattractant protein-1, and 8-isoprostane (prostaglandin F(2)alpha) that were positively correlated with extensive infiltration of SP(-/-) ovarian tumors and ascites with macrophages. In summary, our findings strongly suggest that host SPARC normalizes the microenvironment of ovarian cancer malignant ascites through down-regulation of the VEGF-integrin-MMP axis, decreases the levels and activity of bioactive lipids, and ameliorates downstream inflammation.
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Affiliation(s)
- Neveen Said
- Vascular Biology Center, Medical College of Georgia, Augusta, Georgea 30912, USA
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69
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Boultwood J, Pellagatti A, Cattan H, Lawrie CH, Giagounidis A, Malcovati L, Porta MGD, Jädersten M, Killick S, Fidler C, Cazzola M, Hellström-Lindberg E, Wainscoat JS. Gene expression profiling of CD34+cells in patients with the 5q− syndrome. Br J Haematol 2007; 139:578-89. [DOI: 10.1111/j.1365-2141.2007.06833.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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