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ABSTRACT: Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes tumor progression in different tumor models in an autocrine and paracrine manner. However, at the same time GM-CSF is used in cancer therapies to ameliorate neutropenia. We have previously shown in GM-CSF and G-CSF expressing or negative skin or head and neck squamous cell carcinoma that GM-CSF expression is associated with a highly angiogenic and invasive tumor phenotype. To determine the functional contribution of GM-CSF to tumor invasion, we stably transfected a GM-CSF negative colon adenocarcinoma cell line HT-29 with GM-CSF or treated the same cell line with exogenous GM-CSF. While GM-CSF overexpression and treatment reduced tumor cell proliferation and tumor growth in vitro and in vivo, respectively, it contributed to tumor progression. Together with an enhanced migratory capacity in vitro, we observed a striking increase in tumor cell invasion into the surrounding tissue concomitant with the induction of an activated tumor stroma in GM-CSF overexpressing or GM-CSF treated tumors. In a complex 3D in vitro model, enhanced GM-CSF expression was associated with a discontinued basement membrane deposition that might be mediated by the increased expression and activation of MMP-2, -9, and -26. Treatment with GM-CSF blocking antibodies reversed this effect. The increased presence and activity of these tumor cell derived proteases was confirmed in vivo. Here, expression of MMP-26 protein was predominantly located in pre- and early-invasive areas suggesting MMP-26 expression as an early event in promoting GM-CSF dependent tumor invasion.
Cancer medicine. 04/2013; 2(2):117-29.
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ABSTRACT: Interleukin-6 (IL-6) is one of the major inflammatory interleukins that has been linked to cancer progression. In our model for human skin squamous cell carcinoma (SCC), IL-6 expression is strongly upregulated upon progression from benign tumors to highly malignant, metastasizing SCCs. We now demonstrate that IL-6 promotes malignant and invasive tumor growth in human skin SCCs by inducing cell type specific cytokine profiles in tumor keratinocytes and stromal fibroblasts, activating the latter towards a tumor associated fibroblast (TAF) phenotype. In 3 dimensional organotypic cocultures in vitro invasive growth of IL-6 overexpressing tumor keratinocytes, is associated with increased expression of matrix metalloproteinase-2 (MMP-2), MMP-14 and tissue inhibitor of metalloproteinases-2 (TIMP-2), and clearly depends on IL-6 activated fibroblasts. IL-6-induced secretion of monocyte chemotactic protein-1 (MCP-1) in tumor keratinocytes and of hepatocyte growth factor (HGF) in fibroblasts is crucial for regulating expression and activation of MMP-2. This functional role of IL-6 is confirmed in vivo. Here MMP-14 and MMP-2 expression occur exclusively in surface transplants of IL-6 overexpressing keratinocytes and fibroblasts are identified as important source of MMP-2. Our data indicate that tumor keratinocytes derived IL-6 activates stromal fibroblasts towards a TAF phenotype, promoting tumor invasion via enhanced expression and activation of MMP-2. © 2012 Wiley Periodicals, Inc.
International Journal of Cancer 11/2012; · 5.44 Impact Factor
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ABSTRACT: Inflammation contributes to tumour growth, invasion and angiogenesis. We investigated the contribution of macrophages and their polarization to tumour progression in a model of VEGF-A-induced skin carcinogenesis. Transfection of the human non-tumourigenic keratinocyte cell line HaCaT with murine VEGF-A leads to malignant tumour growth in vivo. The resulting tumours are characterized by extensive vascularization, invasive growth and high numbers of M2-polarized macrophages that crucially contribute to the establishment of the malignant phenotype. Accordingly, macrophage depletion from tumour-bearing animals resulted in reduced tumour growth, inhibition of invasion, decreased proliferation and reduced angiogenesis. In vitro, VEGF-A exerted a chemo-attracting effect on macrophages, but did not induce M2 polarization. We identified IL-4 and IL-10 as the factors involved in M2 polarization. These factors were produced by tumour cells (IL-10) and macrophages (IL-4) in vivo. Addition of recombinant IL-4 and IL-10 in vitro induced a pro-invasive M2 macrophage phenotype and inhibition of the IL-4 receptor in vivo blocked M2 polarization of macrophages, resulting in a less aggressive tumour phenotype. Thus, we provide evidence that M2 macrophages are crucial for the development of VEGF-A-induced skin tumours and that VEGF-A contributes to malignant tumour growth, not only by enhancing angiogenesis but also by establishing an anti-inflammatory microenvironment. However, VEGF-A alone is not sufficient to create a tumour-promoting microenvironment and requires the presence of IL-4 and IL-10 to induce M2 polarization of macrophages.
The Journal of Pathology 01/2012; 227(1):17-28. · 6.32 Impact Factor
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ABSTRACT: Tumor progression is controlled by signals from cellular and extra-cellular microenvironment including stromal cells and the extracellular matrix. Consequently, three-dimensional in vitro tumor models are essential to study the interaction of tumor cells with their microenvironment appropriately in a biologically relevant manner. We have previously used organotypic co-cultures to analyze the malignant growth of human squamous cell carcinoma (SCC) cell lines on a stromal equivalent in vitro. In this model, SCC cell lines are grown on a collagen-I gel containing fibroblasts. Since macrophages play a critical role in the progression of many tumor types, we now have expanded this model by integrating macrophages into the collagen gel of these organotypic tumor co-cultures. This model was established as a murine and a human system of skin SCCs. The effect of macrophages on tumor progression depends on their polarization. We demonstrate that macrophage polarization in organotypic co-cultures can be modulated towards and M1 or an M2 phenotype by adding recombinant IFN-γ and LPS or IL-4 respectively to the growth medium. IL-4 stimulation of macrophage-containing cultures resulted in enhanced tumor cell invasion evidenced by degradation of the basement membrane, enhanced collagenolytic activity and increased MMP-2 and MMP-9. Interestingly, extended co-culture with tumor cells for three weeks resulted in spontaneous M2 polarization of macrophages without IL-4 treatment. Thus, we demonstrate that macrophages can be successfully integrated into organotypic co-cultures of murine or human skin SCCs and that this model can be exploited to analyze macrophage activation towards a tumor supporting phenotype.
PLoS ONE 01/2012; 7(7):e40058. · 4.09 Impact Factor
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ABSTRACT: Cytokines play a crucial role in tumor initiation and progression. Here, we demonstrate that interleukin (IL)-6 is a key factor by driving tumor progression from benign to malignant, invasive tumors in the HaCaT-model of human skin carcinoma. IL-6 activates STAT3 and directly stimulates proliferation and migration of the benign noninvasive HaCaT-ras A-5 cells in vitro. Furthermore, IL-6 induces a complex, reciprocally regulated cytokine network in the tumor cells that includes inflammatory and angiogenic factors such as IL-8, GM-CSF, VEGF and MCP-1. These IL-6 effects lead to tumor cell invasion in organotypic cultures in vitro and to the formation of malignant and invasive s.c. tumors in vivo. Tumor invasion is supported by the IL-6 induced overexpression of MMP-1 in vitro and in vivo. These data demonstrate a key function of IL-6 in the progression of skin SCCs by regulating a complex cytokine and protease network and suggest new therapeutic approaches to target this central player in skin carcinogenesis.
International Journal of Cancer 06/2011; 128(12):2803-14. · 5.44 Impact Factor
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ABSTRACT: Cytokines play a crucial role in tumor initiation and progression. Here, we demonstrate that interleukin (IL)-6 is a key factor by driving tumor progression from benign to malignant, invasive tumors in the HaCaT-model of human skin carcinoma. IL-6 activates STAT3 and directly stimulates proliferation and migration of the benign noninvasive HaCaT-ras A-5 cells in vitro. Furthermore, IL-6 induces a complex, reciprocally regulated cytokine network in the tumor cells that includes inflammatory and angiogenic factors such as IL-8, GM-CSF, VEGF and MCP-1. These IL-6 effects lead to tumor cell invasion in organotypic cultures in vitro and to the formation of malignant and invasive s.c. tumors in vivo. Tumor invasion is supported by the IL-6 induced overexpression of MMP-1 in vitro and in vivo. These data demonstrate a key function of IL-6 in the progression of skin SCCs by regulating a complex cytokine and protease network and suggest new therapeutic approaches to target this central player in skin carcinogenesis.
International Journal of Cancer 11/2010; 128(12):2803 - 2814. · 5.44 Impact Factor
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ABSTRACT: Tumor invasion requires intense interactions with stromal cells and a profound extracellular matrix remodelling by matrix metalloproteinases (MMPs). Here, we assessed the specific contribution of fibroblasts to tumor invasion, MMPs, tissue inhibitors of MMPs and angiogenesis-related cytokine expression in organotypic cultures of highly malignant HaCaT-ras A-5RT3 cells, with and without MMP inhibition. Collagen degradation, the hallmark of tumor invasion, was dependent on fibroblasts and active MMP-2. Additionally, MMP blockade down-regulated VEGF-A and up-regulated PDGF-BB. These results were paralleled in xenotransplants in vivo, demonstrating strong inhibitory effects of MMP blockade on tumor invasion and vascularization, as shown by the almost complete absence of VEGF-A and MMP-14 and by the decrease in relative blood volume. MMP blockade also increased the fraction of mature vessels, as demonstrated by an increased mean tumor vessel diameter and a higher ratio of Ng2-positive vessels. Thus, this study highlights the importance of targeting the tumor stroma to defeat cancer.
Anticancer research 03/2010; 30(3):703-11. · 1.73 Impact Factor
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ABSTRACT: Vascular endothelial growth factor (VEGF), which is a key regulator of angiogenesis, often induces formation of immature vessels with increased permeability and reduced vessel functionality. Here, we demonstrate that de novo expression of murine (m)VEGF-164 induces malignant and invasive tumor growth of HaCaT keratinocytes. However, the mVEGF-164-induced tumors are ulcerated with a disorganized epithelium that is interrupted by lacunae with limited basement membrane and endothelial cell coverage. Vessel maturation is strongly impaired. Tumor and vessel micromorphology are markedly improved by the combined expression of human platelet-derived growth factor (hPDGF)-B and mVEGF-164. Although tumor size and malignancy are comparable with either mVEGF-164 alone or combined human PDGF-B and mVEGF-164 expression, combined hPDGF-B and mVEGF-164 expression leads to a more solid and compact tumor tissue with a mature functional tumor vasculature and a higher microvessel density, as demonstrated histologically and by dynamic contrast-enhanced magnetic resonance imaging. Treatment of the hPDGF-B- and mVEGF-164-expressing tumors with imatinib mesylate to block PDGF-B signaling reverses this effect. In addition, tumor cell invasion of mVEGF-164 transfectants and mVEGF-164 plus hPDGF-B transfectants in vivo is associated with a marked induction of tumor-derived matrix metalloproteinase-1 and stromal matrix metalloproteinase-9 and -13, as was confirmed in three-dimensional organotypic co-cultures with fibroblasts in vitro. These data clearly demonstrate the need for a concerted action of different growth factors in the establishment of solid tumors with functional vasculature and emphasize the need for a multifactorial therapy.
American Journal Of Pathology 02/2010; 176(2):981-94. · 4.89 Impact Factor
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ABSTRACT: Matrix metalloproteinases (MMPs) such as MMP13 promote tumour growth and progression by mediating extracellular matrix (ECM) reorganization and regulating the biological activity of cytokines. Using Mmp13-/- mice, we demonstrate an essential role of this single collagenase for highly malignant and invasive growth in skin squamous cell carcinoma (SCC). Lack of host MMP13 strongly impaired tumour growth of malignant SCC cells, leading to small, mostly avascular cysts. While initial stromal activation in tumour transplants of Mmp13+/+ and Mmp13-/- animals was similar, MMP13 was essential for maintenance of angiogenesis and for invasion. MMP13 was induced in fibroblasts of the wild-type animals at the onset of invasion and correlated with a strong increase in vascular endothelial growth factor (VEGF) protein and its association with vascular endothelial growth factor receptor-2 on endothelial cells in invasive areas. In contrast, VEGF protein in the stroma was barely detectable and tumour invasion was downregulated in Mmp13-/- animals, despite ongoing VEGF messenger RNA expression. Taken together with in vitro data showing the release of VEGF from the ECM by MMP13 expressing fibroblasts, these data strongly suggest a crucial role of MMP13 in promoting angiogenesis via releasing VEGF from the ECM and thus allowing the invasive growth of the SCC cells.
Carcinogenesis 11/2009; 31(7):1175-84. · 5.70 Impact Factor
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Fabian Kiessling,
Jochen Huppert,
Chunfu Zhang,
Jabadurai Jayapaul,
Stefan Zwick,
Eva C Woenne, Margareta M Mueller,
Hanswalter Zentgraf,
Michael Eisenhut,
Yoseph Addadi,
Michal Neeman,
Wolfhard Semmler
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ABSTRACT: To investigate the biologic effect of arginine-glycine-aspartic acid (RGD)-labeled ultrasmall superparamagnetic iron oxide (USPIO) (referred to as RGD-USPIO) on human umbilical vein endothelial cells (HUVECs), ovarian carcinoma (MLS) cells, and glioblastoma (U87MG) cells and on U87MG xenografts in vivo.
All experiments were approved by the governmental review committee on animal care.USPIOs were coated with integrin-specific (RGD) or unspecific (arginine-alanine-aspartic acid [RAD]) peptides. USPIO uptake in HUVECs, MLS cells, and U87MG cells and in U87MG tumor xenografts was determined with T2 magnetic resonance (MR) relaxometry in 16 nude mice. Cells and tumors were characterized by using immunofluorescence microscopy. Trypan blue staining and lactate dehydrogenase assay were used to assess cytotoxicity. Statistical evaluation was performed by using a Mann-Whitney test or a linear mixed model with random intercept for the comparison of data from different experiments. Post hoc pairwise comparisons were adjusted according to a Tukey test.
HUVECs and MLS cells internalized RGD-USPIOs significantly more than unspecific probes. Controversially, U87MG cells accumulated RGD-USPIOs to a lesser extent than USPIO. Furthermore, only in U87MG cells, free RGD and alpha(v)beta(3) integrin-blocking antibodies strongly reduced endocytosis of nonspecific USPIOs. This was accompanied by a loss of cadherin-dependent intercellular contacts, which could not be attributed to cell damage. In U87MG tumors, RGD-USPIO accumulated exclusively at the neovasculature but not within tumor cells. The vascular accumulation of RGD-USPIO caused significantly higher changes of the R2 relaxation rate of tumors than observed for USPIO.
In glioma cells with unstable intercellular contacts, inhibition of alpha(v)beta(3) integrins by antibodies and RGD and RGD-USPIO disintegrated intercellular contacts and reduced endocytotic activity, illustrating the risk of inducing biologic effects by using molecular MR probes.
Radiology 09/2009; 253(2):462-9. · 5.73 Impact Factor
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ABSTRACT: Matrix metalloproteinases (MMPs) are critically involved in tumor invasion and metastasis. However, failure of broad spectrum MMP inhibitors in clinical trials emphasizes the need for detailed analyses of the specific role of different MMPs in tumor malignancy. Using HaCaT-keratinocyte clones representing distinct stages in skin squamous cell carcinoma (SCC) progression, we demonstrate the expression of specific tumor and stroma-derived MMPs with the onset and maintenance of tumor invasion. Although MMP-9-positive leukocytes are present in benign and malignant tumor transplants at the onset of stromal activation and angiogenesis, mRNA expression of stroma-derived MMP-9 as well as MMP-2, -13 and -14 is exclusively found in enhanced malignant tumor transplants. Their expression initiates with the onset of invasion, whereas being absent in early noninvasive stages of malignant transplants. In addition, a high expression of tumor-derived MMP-1, -2 and -14 contributes to malignant and invasive tumor growth. However, stroma-derived MMP-3 is exclusively restricted to very late-stage invasive and malignant transplants. The functional contribution of these proteases to invasive growth is supported by the gelatinolytic activity in the tumor transplants that again initiates with the onset of invasive growth suggesting a crucial role of MMP-2, -9, -13 and -14 for the establishment of a reactive stroma that promotes tumor invasion. These data demonstrate a complex cooperation of distinct tumor and stroma-derived MMPs in the establishment of malignant tumors and provide the basis for a more specific use of highly selective MMP inhibitors during distinct stages of tumor progression.
International Journal of Cancer 06/2009; 125(10):2296-306. · 5.44 Impact Factor
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ABSTRACT: The sensitivity of Doppler ultrasound below 10 MHz to assess antiangiogenic therapy effects in tumor xenografts has been shown to be limited. Thus, our aim was to evaluate high-frequency volumetric power-Doppler ultrasound (HF-VPDU) for monitoring antiangiogenic treatments. Squamous cell carcinoma xenografts grown in nude mice were scanned with HF-VPDU at a center frequency of 30 MHz. Images with 200-microm slice thicknesses were recorded and merged into a three-dimensional dataset, of which the relative color pixel density was determined. Animals received either VEGFR2 antibodies or 0.9% NaCl and were examined at days 0, 3 and 6 of treatment. After the last examination, tumors were resected and their vascularization characterized by immunohistology. At day 6, the volumes of treated and untreated tumors were not significantly different yet. In contrast, mean tumor vascularization in treated animals had decreased to 44%, while in the control group it had increased to 152% (P < 0.01). In correspondence, vessel density, as determined by CD31 staining, was 0.19 +/- 0.10% in treated and 0.92 +/- 0.41% in untreated tumors (P < 0.01). Additionally, the fraction of mature (SMA-positive) vessels increased under therapy. Thus, HF-VPDU can be considered as an easily applicable and fast method to screen high animal numbers for antiangiogenic therapy effects.
European Radiology 04/2008; 18(4):753-8. · 3.22 Impact Factor
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Moritz Palmowski,
Jochen Huppert,
Gesa Ladewig,
Peter Hauff,
Michael Reinhardt, Margareta M Mueller,
Eva C Woenne,
Juergen W Jenne,
Mathias Maurer,
Guenter W Kauffmann,
Wolfhard Semmler,
Fabian Kiessling
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ABSTRACT: Molecular ultrasound is capable of elucidating the expression of angiogenic markers in vivo. However, the capability of the method for volumetric "multitarget quantification" and for the assessment of antiangiogenic therapy response has rather been investigated. Therefore, we generated cyanoacrylate microbubbles linked to vascular endothelial growth factor receptor 2 (VEGFR2) and alphavbeta3 integrin binding ligands and quantified their accumulation in squamous cell carcinoma xenografts (HaCaT-ras-A-5RT3) in mice with the quantitative volumetric ultrasound scanning technique, sensitive particle acoustic quantification. Specificity of VEGFR2 and alphavbeta3 integrin binding microbubbles was shown, and changes in marker expression during matrix metalloproteinase inhibitor treatment were investigated. In tumors, accumulation of targeted microbubbles was significantly higher compared with nonspecific ones and could be inhibited competitively by addition of the free ligand in excess. Also, multimarker imaging could successfully be done during the same imaging session. Molecular ultrasound further indicated a significant increase of VEGFR2 and alphavbeta3 integrin expression during tumor growth and a considerable decrease in both marker densities after matrix metalloproteinase inhibitor treatment. Histologic data suggested that the increasing VEGFR2 and alphavbeta3 integrin concentrations in tumors during growth are related to an up-regulation of its expression by the endothelial cells, whereas its decrease under therapy is more related to the decreasing relative vessel density. In conclusion, targeted ultrasound appears feasible for the longitudinal molecular profiling of tumor angiogenesis and for the sensitive assessment of therapy effects in vivo.
Molecular Cancer Therapeutics 02/2008; 7(1):101-9. · 5.23 Impact Factor
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ABSTRACT: The tumor is a complex system comprising neoplastic genetically altered cells and a tumor stroma composed of remodeled extracellular
matrix, newly formed vessels, and infiltrating host cells. The development of a cancer is a progressive multistep process
in which neoplastic cells progress to malignancy by activating their microenvironment and by responding to the tumor-supporting
cues of the surrounding tissue. Because of the recently recognized importance of a permissive stroma for tumor development
and invasion, the host compartment is now viewed as an interesting new target for tumor therapy. Among positive regulators
contributing to the elaboration of this permissive stroma are growth factors, cytokines/chemokines, proteases, and their inhibitors.
The present review summarizes what we learned during the last decade on the contribution of these factors at the tumor–host
interface by exploiting a useful in vivo surface transplantation model of skin carcinomas.
12/2007: pages 327-342;
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ABSTRACT: Interactions between cancer cells and the tissue microenvironment play an essential role in controlling tumor development and progression. Here, we report that stromal modulation induced by a biodegradable meshwork (Hyalograft 3D) inhibited tumor vascularization and invasion of the locally invasive low-grade malignant human HaCaT-ras II-4 keratinocytes in a surface xenotransplantation assay. The scaffold caused formation of an active granulation tissue that shifted to a fibrotic-type connective tissue with accumulation of myofibroblasts and collagen bundles. Most importantly, in transplants with scaffolds, the epithelial-stromal border was normalized developing an ultrastructurally complete basement membrane (BM) including hemidesmosomes. The observed reversion of the tumor phenotype was not due to decreased tumor cell proliferation but correlated with (i) normalization of epidermal differentiation, (ii) condensation of extracellular matrix (ECM) and (iii) reduction of peritumoral protease activity Furthermore, inhibited invasion was paralleled by eliminated tumor vascularization. This was substantiated by a diminished endothelial VEGF-receptor (VEGFR) expression and, in turn, by a concomitant increase in the ECM components thrombospondin-1 (TSP-1) and endostatin, known to impair angiogenesis. Even in transplants of the metastatic high-grade malignant HaCaT-ras A-5RT3 keratinocytes the anti-invasive effect of the scaffold-modulated stroma prevailed. Tumor vascularization and invasion was reduced and the epithelial tissue partially normalized including formation of stretches of BM. This clearly demonstrates that the scaffold-modulated connective tissue not only blocks tumor invasion but reverts the tumor phenotype. These novel findings underline the controlling function of tumor stroma and open new strategies of cancer therapy by targeting tumor stroma elements.
Carcinogenesis 04/2007; 28(3):595-610. · 5.70 Impact Factor
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Chunfu Zhang,
Manfred Jugold,
Eva C Woenne,
Twan Lammers,
Bernd Morgenstern, Margareta M Mueller,
Hanswalter Zentgraf,
Michael Bock,
Michael Eisenhut,
Wolfhard Semmler,
Fabian Kiessling
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ABSTRACT: Angiogenesis is essential for the development of malignant tumors and provides important targets for tumor diagnosis and therapy. To noninvasively assess the angiogenic profile of tumors, novel alpha(v)beta(3) integrin-targeted ultrasmall superparamagnetic iron oxide particles (USPIOs) were designed and their specific uptake by endothelial cells was evaluated in vitro and in vivo. USPIOs were coated with 3-aminopropyltrimethoxysilane (APTMS) and conjugated with Arg-Gly-Asp (RGD) peptides. Accumulation in human umbilical vein endothelial cells (HUVECs) was evaluated using Prussian blue staining, transmission electron microscopy, magnetic resonance (MR) imaging, and inductively coupled plasma mass spectrometry. Uptake of RGD-USPIO by HUVECs was significantly increased when compared with unlabeled USPIO and could be competitively inhibited by addition of unbound RGD. The ability of the RGD-USPIO to noninvasively distinguish tumors with high (HaCaT-ras-A-5RT3) and lower (A431) area fractions of alpha(v)beta(3) integrin-positive vessels was evaluated using a 1.5-T MR scanner. Indeed, after RGD-USPIO injection, there was a more pronounced decrease in T(2) relaxation times in HaCaT-ras-A-5RT3 tumors than in A431 tumors. Furthermore, T(2)*-weighted images clearly identified the heterogeneous arrangement of vessels with alpha(v)beta(3) integrins in HaCaT-ras-A-5RT3 tumors by an irregular signal intensity decrease. In contrast, in A431 tumors with predominantly small and uniformly distributed vessels, the signal intensity decreased more homogeneously. In summary, RGD-coupled, APTMS-coated USPIOs efficiently label alpha(v)beta(3) integrins expressed on endothelial cells. Furthermore, these molecular MR imaging probes are capable of distinguishing tumors differing in the degree of alpha(v)beta(3) integrin expression and in their angiogenesis profile even when using a clinical 1.5-T MR scanner.
Cancer Research 03/2007; 67(4):1555-62. · 7.86 Impact Factor
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ABSTRACT: Platelet-derived growth factor (PDGF) stimulates tumor growth and progression by affecting tumor and stromal cells. In the HaCaT skin carcinogenesis model, transfection of immortal nontumorigenic and PDGF-receptor-negative HaCaT keratinocytes with PDGF-B induced formation of benign tumors. Here, we present potential mechanisms underlying this tumorigenic conversion. In vivo, persistent PDGF-B expression induced enhanced tumor cell proliferation but only transiently stimulated stromal cell proliferation and angiogenesis. In vitro and in vivo studies identified fibroblasts as PDGF target cells essential for mediating transient angiogenesis and persistent epithelial hyperproliferation. In fibroblast cultures, long-term PDGF-BB treatment caused an initial up-regulation of vascular endothelial growth factor (VEGF)-A, followed by a drastic VEGF down-regulation and myofibroblast differentiation. Accordingly, in HaCaT/PDGF-B transplants, initially enhanced VEGF expression by stromal fibroblasts was subsequently reduced, followed by down-regulation of angiogenesis, myofibroblast accumulation, and vessel maturation. The PDGF-induced, persistently increased expression of the hepatocyte growth factor by fibroblasts in vitro and in vivo was most probably responsible for enhanced epithelial cell proliferation and benign tumor formation. Thus, by paracrine stimulation of the stroma, PDGF-BB induced epithelial hyperproliferation, thereby promoting tumorigenicity, whereas the time-limited activation of the stroma followed by stromal maturation provides a possible explanation for the benign tumor phenotype.
American Journal Of Pathology 12/2006; 169(5):1767-83. · 4.89 Impact Factor
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ABSTRACT: Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are used to ameliorate cancer therapy-induced neutropenia and mucositis. Yet, first data in head and neck squamous cell carcinoma (HNSCC) indicate an impaired long-term prognosis on G-CSF treatment, and previous studies showed a contribution of both factors to the progression of human epithelial tumors. Therefore, we investigate the role of G-CSF and GM-CSF in progression of tumor cells from human HNSCC. Both factors stimulated proliferation and migration of tumor cell lines established from patient tumors expressing G-CSF and GM-CSF and/or their receptors. Blockade of G-CSF and GM-CSF inhibited tumor cell invasion in a three-dimensional organotypic culture model. The contribution of both factors to tumor malignancy was further confirmed in nude mouse transplants in vivo. Invasive and malignant growth yielding a similar tumor phenotype as the original patient tumor was exclusively observed in G-CSF- and GM-CSF-expressing tumors and was associated with enhanced and persistent angiogenesis and enhanced inflammatory cell recruitment. Although factor-negative tumors grew somewhat faster, they were characterized by lack of invasion, reduced and transient angiogenesis, and large necrotic areas. These data provide evidence for a progression-promoting effect of G-CSF and GM-CSF in human HNSCC and suggest further detailed evaluation of their use in the therapy of these tumors.
Cancer Research 09/2006; 66(16):8026-36. · 7.86 Impact Factor
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Susanne Greschus,
Fabian Kiessling,
Matthias P Lichy,
Jens Moll, Margareta M Mueller,
Rajkumar Savai,
Frank Rose,
Clemens Ruppert,
Andreas Günther,
Marcus Luecke,
Norbert E Fusenig,
Wolfhard Semmler,
Horst Traupe
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ABSTRACT: Noninvasive radiologic imaging has recently gained considerable interest in basic and preclinical research for monitoring disease progression and therapeutic efficacy. In this report, we introduce flat-panel volumetric computed tomography (fpVCT) as a powerful new tool for noninvasive imaging of different organ systems in preclinical research. The three-dimensional visualization that is achieved by isotropic high-resolution datasets is illustrated for the skeleton, chest, abdominal organs, and brain of mice. The high image quality of chest scans enables the visualization of small lung nodules in an orthotopic lung cancer model and the reliable imaging of therapy side effects such as lung fibrosis. Using contrast-enhanced scans, fpVCT displayed the vascular trees of the brain, liver, and kidney down to the subsegmental level. Functional application of fpVCT in dynamic contrast-enhanced scans of the rat brain delivered physiologically reliable data of perfusion and tissue blood volume. Beyond scanning of small animal models as demonstrated here, fpVCT provides the ability to image animals up to the size of primates.
Neoplasia 09/2005; 7(8):730-40. · 5.95 Impact Factor
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Rui Sun,
Julia Dittrich,
Martin Le-Huu, Margareta M Mueller,
Jens Bedke,
Juergen Kartenbeck,
Wolf D Lehmann,
Ralf Krueger,
Michael Bock,
Ralf Huss,
Christian Seliger,
Herrmann-Josef Gröne,
Bernd Misselwitz,
Wolfhard Semmler,
Fabian Kiessling
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ABSTRACT: Superparamagnetic iron-oxide particles are used frequently for cellular magnetic resonance imaging and in vivo cell tracking. The purpose of this study was to compare the labeling characteristics and efficiency as well as toxicity of superparamagnetic iron oxide (SPIO) and ultrasmall superparamagnetic iron oxide (USPIO) for 3 cell lines.
Using human fibroblasts, immortalized rat progenitor cells and HEP-G2-hepatoma cells, dose- and time-dependence of SPIO and USPIO uptake were evaluated. The amount of intracellular (U)SPIO was monitored over 2 weeks after incubation by T2-magnetic resonance relaxometry, ICP-mass-spectrometry, and histology. Transmission-electronmicroscopy was used to specify the intracellular localization of the endocytosed iron particles. Cell death-rate and proliferation-index were assessed as indicators of cell-toxicity.
For all cell lines, SPIO showed better uptake than USPIO, which was highest in HEP-G2 cells (110 +/- 2 pg Fe/cell). Cellular iron concentrations in progenitor cells and fibroblasts were 13 +/- 1pg Fe/cell and 7.2 +/- 0.3pg Fe/cell, respectively. For all cell lines T2-relaxation times in cell pellets were below detection threshold (<3 milliseconds) after 5 hours of incubation with SPIO (3.0 micromol Fe/mL growth medium) and continued to be near the detection for the next 6 days. For both particle types and all cell lines cellular iron oxide contents decreased after recultivation and surprisingly were found lower than in unlabeled control cells after 15 days. Viability and proliferation of (U)SPIO-labeled and unlabeled cells were not significantly different.
The hematopoetic progenitor, mesenchymal fibroblast and epithelial HEP-G2 cell lines accumulated SPIO more efficiently than USPIO indicating SPIO to be better suited for cell labeling. However, the results indicate that there may be an induction of forced cellular iron elimination after incubation with (U)SPIO.
Investigative Radiology 08/2005; 40(8):504-13. · 4.59 Impact Factor
