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ABSTRACT: Hedgehog (Hh) signaling modulates T cell development and function but its exact role remains a matter of debate. To further address this issue we made use of conditional knock-out mice in which the Hh receptor Patched1 (Ptch) is inactivated in the T cell lineage. Thymocyte development was moderately compromised by the deletion of Ptch as characterized by reduced numbers of CD4 and CD8 single-positive cells. In contrast, peripheral T cells were not affected. Proliferation and IFNγ secretion by Ptch-deficient T cells were indistinguishable from controls irrespectively of whether we used strong or suboptimal conditions for stimulation. Analysis of CTL and Treg cell functions did not reveal any differences between both genotypes, and T cell apoptosis induced by glucocorticoids or γ-irradiation was also similar. Surprisingly, absence of Ptch did not lead to an activation of canonic Hh signaling in peripheral T cells as indicated by unaltered expression levels of Gli1 and Gli2. To test whether we could uncover any role of Ptch in T cells in vivo we subjected the mutant mice to three different disease models, namely allogeneic bone marrow transplantation mimicking graft-versus-host disease, allergic airway inflammation as a model of asthma and growth of adoptively transferred melanoma cells as a means to test tumor surveillance by the immune system. Nonetheless, we were neither able to demonstrate any difference in the disease courses nor in any pathogenic parameter in these three models of adaptive immunity. We therefore conclude that the Hh receptor Ptch is dispensable for T cell function in vitro as well as in vivo.
PLoS ONE 01/2013; 8(4):e61034. · 4.09 Impact Factor
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Penelope Pelczar,
Arne Zibat,
Willemijn A van Dop,
Jarom Heijmans,
Annalen Bleckmann,
Wolfgang Gruber,
Frauke Nitzki,
Anja Uhmann,
Maria V Guijarro,
Eva Hernando, [......],
Claudia Binder,
Takahiro Taguchi,
Tim Beissbarth,
Pancras C W Hogendoorn,
Cristina R Antonescu,
Brian P Rubin,
Walter Schulz-Schaeffer,
Fritz Aberger,
Gijs R van den Brink, Heidi Hahn
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ABSTRACT: BACKGROUND & AIMS:: A fraction of gastrointestinal stromal tumor (GIST) cells overexpress the platelet-derived growth factor receptor (PDGFR)A, although most overexpress KIT. It is not known if this is because these receptor tyrosine kinases have complementary oncogenic potential, or because of heterogeneity in the cellular origin of GIST. Little is also known about why Hedgehog (HH) signaling is activated in some GIST. HH binds to and inactivates the receptor protein patched homolog (PTCH). METHODS:: Ptch was conditionally inactivated in mice (to achieve constitutive HH signaling) using a Cre recombinase regulated by the lysozyme M (LysM) promoter. Cre-expressing cells were traced using R26R-LacZ reporter mice. Tumors were characterized by in situ hybridization, immunohistochemistry, immunoblot, and quantitative reverse transcriptase PCR analyses. Cell transformation was assessed by soft agar assay. RESULTS:: Loss of Ptch from LysM-expressing cells resulted in development of tumors of GIST-like localization and histology; these were reduced when mice were given imatinib, a drug that targets KIT and PDGFRA. The Hh signaling pathway was activated in the tumor cells, and Pdgfrα, but not Kit, was overexpressed and activated. Lineage tracing revealed that Cre-expressing intestinal cells were Kit-negative. These cells sometimes expressed Pdgfrα and were located near Kit-positive interstitial cells of Cajal (ICC). In contrast to KIT, activation of PDGFRA increased anchorage-independent proliferation and was required for tumor formation in mice by cells with activated HH signaling. CONCLUSIONS:: Inactivation of Ptch in mice leads to formation of GIST-like tumors that express Pdgfrα, but not Kit. Activation of Pdgfrα signaling appears to facilitate tumorigenesis.
Gastroenterology 10/2012; · 11.68 Impact Factor
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Willemijn A van Dop,
Sanne L Rosekrans,
Anja Uhmann,
Viljar Jaks,
G Johan A Offerhaus,
Marius A van den Bergh Weerman,
Maria Kasper,
Jarom Heijmans,
James C H Hardwick,
Hein W Verspaget,
Daan W Hommes,
Rune Toftgård, Heidi Hahn,
Gijs R van den Brink
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ABSTRACT: OBJECTIVE: In the intestine Hedgehog (Hh) signalling is directed from epithelium to mesenchyme and negatively regulates epithelial precursor cell fate. The role of Hh signalling in the oesophagus has not been studied in vivo. Here the authors examined the role of Hh signalling in epithelial homeostasis of oesophagus. DESIGN: The authors used transgenic mice in which the Hh receptor Patched1 (Ptch1) could be conditionally inactivated in a body-wide manner and mice in which Gli1 could be induced specifically in the epithelium of the skin and oesophagus. Effects on epithelial homeostasis of the oesophagus were examined using immunohistochemistry, in situ hybridisation, transmission electron microscopy and real-time PCR. Hh signalling was examined in patients with oesophageal squamous cell carcinoma (SCC) by quantitative real-time PCR. RESULTS: Sonic Hh is signalled in an autocrine manner in the basal layer of the oesophagus. Activation of Hh signalling resulted in an expansion of the epithelial precursor cell compartment and failure of epithelial maturation and migration. Levels of Hh targets GLI1, HHIP and PTCH1 were increased in SCC compared with normal tissue from the same patients. CONCLUSION: Here the authors find that Hh signalling positively regulates the precursor cell compartment in the oesophageal epithelium in an autocrine manner. Since Hh signalling targets precursor cells in the oesophageal epithelium and signalling is increased in SCCs, Hh signalling may be involved in oesophageal SCC formation.
Gut 04/2012; · 10.11 Impact Factor
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Diana Marklein,
Ulrike Graab,
Ivonne Naumann,
Tiandong Yan,
Rosalie Ridzewski,
Frauke Nitzki,
Albert Rosenberger,
Kai Dittmann,
Jürgen Wienands,
Leszek Wojnowski,
Simone Fulda, Heidi Hahn
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ABSTRACT: We searched for a drug capable of sensitization of sarcoma cells to doxorubicin (DOX). We report that the dual PI3K/mTOR inhibitor PI103 enhances the efficacy of DOX in several sarcoma cell lines and interacts with DOX in the induction of apoptosis. PI103 decreased the expression of MDR1 and MRP1, which resulted in DOX accumulation. However, the enhancement of DOX-induced apoptosis was unrelated to DOX accumulation. Neither did it involve inhibition of mTOR. Instead, the combination treatment of DOX plus PI103 activated Bax, the mitochondrial apoptosis pathway, and caspase 3. Caspase 3 activation was also observed in xenografts of sarcoma cells in nude mice upon combination of DOX with the specific PI3K inhibitor GDC-0941. Although the increase in apoptosis did not further impact on tumor growth when compared to the efficient growth inhibition by GDC-0941 alone, these findings suggest that inhibition of PI3K may improve DOX-induced proapoptotic effects in sarcoma. Taken together with similar recent studies of neuroblastoma- and glioblastoma-derived cells, PI3K inhibition seems to be a more general option to sensitize tumor cells to anthracyclines.
PLoS ONE 01/2012; 7(12):e52898. · 4.09 Impact Factor
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ABSTRACT: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Aberrant Hedgehog (Hh) signaling is characteristic of the embryonal subtype (ERMS) and of fusion-negative alveolar RMS. In the mouse, ERMS-like tumors can be induced by mutations in the Hh receptor Patched1 (Ptch). As in humans these tumors show increased Hh pathway activity. Here we demonstrate that the treatment with the active form of vitamin D(3), calcitriol, inhibits Hh signaling and proliferation of murine ERMS in vivo and in vitro. Concomitantly, calcitriol activates vitamin D receptor (Vdr) signaling and induces tumor differentiation. In addition, calcitriol inhibits ERMS growth in Ptch-mutant mice, which is, however, a rather late response. Taken together, our results suggest that exogenous supply of calcitriol could be beneficial in the treatment of RMS, especially in those which are associated with aberrant Hh signaling activity.
Sarcoma 01/2012; 2012:357040.
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ABSTRACT: Basal cell carcinoma (BCC) is the most common human tumor. Mutations in the hedgehog (HH) receptor Patched (PTCH) are the main cause of BCC. Due to their high and increasing incidence, BCC are becoming all the more important for the health care system. Adequate animal models are required for the improvement of current treatment strategies. A good model should reflect the situation in humans (i.e., BCC initiation due to Ptch mutations on an immunocompetent background) and should allow for (i) BCC induction at a defined time point, (ii) analysis of defined BCC stages, and (iii) induction of BCC in 100% of animals. In addition, it should be easy to handle. Here, we compare several currently existing conventional and conditional Ptch knockout mouse models for BCC and their potential use in preclinical research. In addition, we provide new data using conditional Ptch(flox/flox) mice and the K5-Cre-ER(T+/-) driver.
Journal of skin cancer. 01/2012; 2012:907543.
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Anja Uhmann,
Hannah Niemann,
Bérénice Lammering,
Cornelia Henkel,
Ina Hess,
Frauke Nitzki,
Anne Fritsch,
Nicole Prüfer,
Albert Rosenberger,
Christian Dullin,
Anke Schraepler,
Julia Reifenberger,
Stefan Schweyer,
Torsten Pietsch,
Frank Strutz,
Walter Schulz-Schaeffer, Heidi Hahn
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ABSTRACT: Activation of the Hedgehog (Hh)-signaling pathway due to deficiency in the Hh receptor Patched1 (Ptch) is the pivotal defect leading to formation of basal cell carcinoma (BCC). Recent reports provided evidence of Ptch-dependent secretion of vitamin D(3)-related compound, which functions as an endogenous inhibitor of Hh signaling by repressing the activity of the signal transduction partner of Ptch, Smoothened (Smo). This suggests that Ptch-deficient tumor cells are devoid of this substance, which in turn results in activation of Hh-signaling. Here, we show that the application of the physiologically active form of vitamin D(3), calcitriol, inhibits proliferation and growth of BCC of Ptch mutant mice in vitro and in vivo. This is accompanied by the activation of the vitamin D receptor (Vdr) and induction of BCC differentiation. In addition, calcitriol inhibits Hh signaling at the level of Smo in a Vdr-independent manner. The concomitant antiproliferative effects on BCC growth are stronger than those of the Hh-specific inhibitor cyclopamine, even though the latter more efficiently inhibits Hh signaling. Taken together, we show that exogenous supply of calcitriol controls the activity of 2 independent pathways, Hh and Vdr signaling, which are relevant to tumorigenesis and tumor treatment. These data suggest that calcitriol could be a therapeutic option in the treatment of BCC, the most common tumor in humans.
Molecular Cancer Therapeutics 08/2011; 10(11):2179-88. · 5.23 Impact Factor
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Anja Uhmann,
Jens van den Brandt,
Kai Dittmann,
Ina Hess,
Ralf Dressel,
Claudia Binder,
Fred Lühder,
Hans Christiansen,
Martin Fassnacht,
Avinash Bhandoola,
Jürgen Wienands,
Holger M Reichardt, Heidi Hahn
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ABSTRACT: We recently described that T cell specification in mice deficient in the Hedgehog (Hh) receptor Patched (Ptch) is blocked at the level of the common lymphoid progenitor in the bone marrow (BM). Adoptive transfer of wild-type BM in Ptch-deficient mice provides evidence that T cell development strictly depends on Ptch expression in the nonhematopoietic compartment. Transplantation experiments using BM deficient in the glucocorticoid receptor exclude any involvement of the stress hormone corticosterone in our model. Using cell-type-specific knockout mice, we show that T cell development is independent of T cell-intrinsic Ptch expression. Furthermore, Ptch expression by the thymus stroma is dispensable, as revealed by fetal thymus organ culture and thymus transplantation. In contrast, analysis of the earliest thymic progenitors in Ptch-deficient mice indicated that Ptch is required for the development or supply of thymic homing progenitors that give rise to earliest thymic progenitors. Collectively, our findings identified Ptch as an exclusive T cell-extrinsic factor necessary for proper development of T cells at their prethymic stage. This observation may be important for current considerations using Hh inhibitors upstream of Ptch in diseases accompanied by aberrant Hh signaling.
The Journal of Immunology 02/2011; 186(6):3383-91. · 5.79 Impact Factor
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Frauke Nitzki,
Arne Zibat,
Simone König,
Mark Wijgerde,
Albert Rosenberger,
Felix H Brembeck,
Per-Ole Carstens,
Anke Frommhold,
Anja Uhmann,
Stefan Klingler,
Julia Reifenberger,
Tobias Pukrop,
Fritz Aberger,
Walter Schulz-Schaeffer, Heidi Hahn
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ABSTRACT: Basal cell carcinoma (BCC) is the most common skin tumor in humans. Although BCCs rarely metastasize, they can cause significant morbidity due to local aggressiveness. Approximately 20% of BCCs show signs of spontaneous regression. The understanding of molecular events mediating spontaneous regression has the potential to reduce morbidity of BCC and, potentially, other tumors, if translated into tumor therapies. We show that BCCs induced in conditional Ptch(flox/flox)ERT2(+/-) knockout mice regress with time and show a more differentiated phenotype. Differentiation is accompanied by Wnt5a expression in the tumor stroma, which is first detectable at the fully developed tumor stage. Coculture experiments revealed that Wnt5a is upregulated in tumor-adjacent macrophages by soluble signals derived from BCC cells. In turn, Wnt5a induces the expression of the differentiation marker K10 in tumor cells, which is mediated by Wnt/Ca(2+) signaling in a CaMKII-dependent manner. These data support a role of stromal Wnt5a in BCC differentiation and regression, which may have important implications for development of new treatment strategies for this tumor. Taken together, our results establish BCC as an easily accessible model of tumor regression. The regression of BCC despite sustained Hedgehog signaling activity seems to be mediated by tumor-stromal interactions via Wnt5a signaling.
Cancer Research 03/2010; 70(7):2739-48. · 7.86 Impact Factor
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The Journal of Immunology 10/2009; 183(5):2891; author reply 2891-2. · 5.79 Impact Factor
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Arne Zibat,
Anja Uhmann,
Frauke Nitzki,
Mark Wijgerde,
Anke Frommhold,
Tanja Heller,
Victor Armstrong,
Leszek Wojnowski,
Leticia Quintanilla-Martinez,
Julia Reifenberger,
Walter Schulz-Schaeffer, Heidi Hahn
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ABSTRACT: Mutations in Patched (PTCH) have been associated with tumors characteristic both for children [medulloblastoma (MB) and rhabdomyosarcoma (RMS)] and for elderly [basal cell carcinoma (BCC)]. The determinants of the variability in tumor onset and histology are unknown. We investigated the effects of the time-point and dosage of Ptch inactivation on tumor spectrum using conditional Ptch-knockout mice. Ptch heterozygosity induced prenatally resulted in the formation of RMS, which was accompanied by the silencing of the remaining wild-type Ptch allele. In contrast, RMS was observed neither after mono- nor biallelic postnatal deletion of Ptch. Postnatal biallelic deletion of Ptch led to BCC precancerous lesions of the gastrointestinal epithelium and mesenteric tumors. Hamartomatous gastrointestinal cystic tumors were induced by monoallelic, but not biallelic Ptch mutations, independently of the time-point of mutation induction. These data suggest that the expressivity of Ptch deficiency is largely determined by the time-point, the gene dose and mode of Ptch inactivation. Furthermore, they point to key differences in the tumorigenic mechanisms underlying adult and childhood tumors. The latter ones are unique among all tumors since their occurrence decreases rather than increases with age. A better understanding of mechanisms underlying this ontological restriction is of potential therapeutic value.
Carcinogenesis 04/2009; 30(6):918-26. · 5.70 Impact Factor
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Willemijn A van Dop,
Anja Uhmann,
Mark Wijgerde,
Esther Sleddens-Linkels,
Jarom Heijmans,
G Johan Offerhaus,
Marius A van den Bergh Weerman,
Guy E Boeckxstaens,
Daan W Hommes,
James C Hardwick, Heidi Hahn,
Gijs R van den Brink
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ABSTRACT: The intestinal epithelium is a homeostatic system in which differentiated cells are in dynamic equilibrium with rapidly cycling precursor cells. Wnt signaling regulates intestinal epithelial precursor cell fate and proliferation. Homeostatic systems exist by virtue of negative feedback loops, and we have previously identified the Hedgehog (Hh) pathway as a potential negative feedback signal in the colonic epithelium. Indian hedgehog (Ihh) is produced by the differentiated enterocytes and negatively regulates Wnt signaling in intestinal precursor cells. We studied the role of members of the Hh signaling family in the intestine using a conditional genetic approach.
We inactivated the Hh receptor Patched1 (Ptch1) in adult mice, resulting in constitutive activation of the Hh signaling pathway. Effects on colonic mucosal homeostasis were examined. Colon tissues were examined by immunohistochemistry, in situ hybridization, transmission electron microscopy, and real-time polymerase chain reaction.
Ihh but not Sonic hedgehog (Shh) was expressed in colonic epithelium. Expression of Ptch1 and Gli1 was restricted to the mesenchyme. Constitutive activation of Hh signaling resulted in accumulation of myofibroblasts and colonic crypt hypoplasia. A reduction in the number of epithelial precursor cells was observed with premature development into the enterocyte lineage and inhibition of Wnt signaling. Activation of Hh signaling resulted in induction of the expression of bone morphogenetic proteins (Bmp) and increased Bmp signaling in the epithelium.
Hh signaling acts in a negative feedback loop from differentiated cells via the mesenchyme to the colonic epithelial precursor cell compartment in the adult mouse.
Gastroenterology 03/2009; 136(7):2195-2203.e1-7. · 11.68 Impact Factor
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Ines Ecke,
Frauke Petry,
Albert Rosenberger,
Svantje Tauber,
Sven Mönkemeyer,
Ina Hess,
Christian Dullin,
Sarah Kimmina,
Judith Pirngruber,
Steven A Johnsen,
Anja Uhmann,
Frauke Nitzki,
Leszek Wojnowski,
Walter Schulz-Schaeffer,
Olaf Witt, Heidi Hahn
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ABSTRACT: Patched (Ptch) heterozygous mice develop medulloblastoma (MB) and rhabdomyosarcoma (RMS) resembling the corresponding human tumors. We have previously shown that epigenetic silencing of the intact Ptch allele contributes to tumor formation in this model. Here, we investigated whether targeting of epigenetic silencing mechanisms could be useful in the treatment of Ptch-associated cancers. A reduction of endogenous DNA methyltransferase1 (Dnmt1) activity significantly reduced tumor incidence in heterozygous Ptch knockout mice. A combined treatment with the Dnmt inhibitor 5-aza-2'deoxycytidine (5-aza-dC) and the histone deacetlyase (HDAC) inhibitor valproic acid (VPA) efficiently prevented MB and RMS formation, whereas monotherapies with either drug were less effective. Wild-type Ptch expression was efficiently reactivated in tumors by 5-aza-dC/VPA combination therapy. This was associated with reduced methylation of the Ptch promoter and induction of histone hyperacetylation suggesting inhibition of HDACs in vivo. However, the treatment was not effective in clinically overt, advanced stage tumors. This is a first in vivo demonstration that targeting of Dnmt and HDAC activities is highly effective in preventing formation of Ptch-associated tumors. The results suggest a novel clinical strategy for consolidation therapy of corresponding tumors in humans after completion of conventional treatment. Our data also suggest that epigenetic therapy may be less effective in treating advanced stages of tumors, at least in this tumor model.
Cancer Research 02/2009; 69(3):887-95. · 7.86 Impact Factor
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ABSTRACT: Mutations in the Hedgehog (Hh) receptor Patched (Ptch) are responsible for a variety of tumors, which show ligand-independent stimulation of the Hh/Ptch signaling cascade. Cyclopamine is an alkaloid of the corn lily Veratrum californicum, which blocks activity of the pathway by inhibition of Smoothened (Smo), the signal transduction partner of Ptch. This results in growth inhibition of Hh/Ptch-dependent tumor cells in vitro, of subcutaneous xenografts as well as of precancerous lesions in Ptch(+/-) mice. However, the evidence that treatment with cyclopamine is an effective anti-cancer therapy against full-blown tumors is sparse. Here, we have investigated the responsiveness of full-blown Hh/Ptch-associated rhabdomyosarcoma (RMS) to this drug. Hh pathway activity and proliferation of cultured primary RMS cells was inhibited by cyclopamine. Hh signaling was also partially suppressed by the drug in RMS in vivo, but cyclopamine treatment did not result in stable disease or tumor regression. It also did not affect proliferation, apoptosis or the differentiation status of RMS. This was in contrast to anti-proliferative effects on tumor growth caused by doxorubicin, an anthracycline routinely used in therapy of human RMS. In summary, our data indicate that there must be additional factors that render full-blown Hh/Ptch-associated RMS insensitive against anti-proliferative effects of cyclopamine in vivo.
Molecular Carcinogenesis 06/2008; 47(5):361-72. · 3.16 Impact Factor
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Anja Uhmann,
Kai Dittmann,
Frauke Nitzki,
Ralf Dressel,
Milena Koleva,
Anke Frommhold,
Arne Zibat,
Claudia Binder,
Ibrahim Adham,
Mirko Nitsche,
Tanja Heller,
Victor Armstrong,
Walter Schulz-Schaeffer,
Jürgen Wienands, Heidi Hahn
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ABSTRACT: A first step in hematopoiesis is the specification of the lymphoid and myeloid lineages from multipotent progenitor cells in the bone marrow. Using a conditional ablation strategy in adult mice, we show that this differentiation step requires Patched (Ptch), the cell surface-bound receptor for Hedgehog (Hh). In the absence of Ptch, the development of T- and B-lymphoid lineages is blocked at the level of the common lymphoid progenitor in the bone marrow. Consequently, the generation of peripheral T and B cells is abrogated. Cells of the myeloid lineage develop normally in Ptch mutant mice. Finally, adoptive transfer experiments identified the stromal cell compartment as a critical Ptch-dependent inducer of lymphoid versus myeloid lineage commitment. Our data show that Ptch acts as a master switch for proper diversification of hematopoietic stem cells in the adult organism.
Blood 10/2007; 110(6):1814-23. · 9.90 Impact Factor
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ABSTRACT: The tumor suppressor gene PATCHED1 (PTCH1) is a member of the hedgehog signaling pathway and causatively associated with several human sporadic and familial cancers, including those of the skin, muscle and brain. Inactivation of one Ptch1 allele in the mouse results in the development of medulloblastoma and rhabdomyosarcoma (RMS), the latter being a malignant tumor of skeletal muscle origin. To identify genes involved in the pathogenesis of Ptch1-associated RMS, we have monitored the expression of 588 genes in RMS and normal skeletal muscle (SM) of heterozygous Ptch1neo67/+ mice using cDNA array technology. RMS displayed increased transcript levels of several genes such as transforming growth factor-beta1 (Tgfb1), insulin-like growth factor 2 (Igf2), villin 2 (Vil2), integrin beta1 (Itgb1), Sloan-Kettering viral oncogene homolog (Ski), and insulin-like growth factor binding protein 3 (Igfbp3), as well as numerous genes coding for structural components of myogenic cells such as myosin light polypeptide 4 (Myl4), myosin light polypeptide 6 (Myl6), and vimentin (Vim). Detailed promoter analysis revealed a putative Gli binding site in the second promoter region (P2) of the murine Tgfb1 gene. However, using reporter assay we show that the P2 promoter is not responsive to hedgehog signaling. We furthermore describe that Tgfb1 expression could not be activated in C2C12 myoblasts in the presence of murine Shh-N peptide and that Tgfb1 is equally expressed in both wild-type and Ptch1-deficient mouse embryos. In line with this, TGFB1 was strongly expressed in human RMS cell lines independently of the GLI1 expression status. In summary, our results suggest that aberrant expression of Tgfb1 may be involved in RMS development in a way that is independent of hedgehog signaling.
International Journal of Oncology 09/2007; 31(2):405-12. · 2.40 Impact Factor
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ABSTRACT: Mutations of the Sonic hedgehog (SHH) receptor, Patched1 (PTCH1), have been identified in a variety of tumors. PTCH1 is usually considered to be a tumor suppressor gene. However, one normal allele is retained in many tumors. We investigated the mechanism of tumorigenesis in murine heterozygous Ptch1 knock-out mice. Here we show that Ptch1 transcripts, which are consistently overexpressed in tumors in these mice, are derived predominantly from the mutated allele. These transcripts give rise to a mutant protein incapable of pathway inhibition. In contrast, the expression of wild-type transcripts in the tumor is reduced. The transcriptional activity of a Ptch1 promoter is sensitive to methylation. Based on these results, we propose a model, in which tumorigenesis begins with the transcriptional silencing of one PTCH1/Ptch1 allele. This alone has no functional consequences. Upon mutational inactivation of the other allele, the resulting loss of PTCH1/Ptch1 function activates PTCH1/Ptch1 transcription from the non-silenced, i.e. the mutant, allele. These events can occur in an opposite order. This model is consistent with the expression of PTCH1/Ptch1-derived transcripts and proteins found in tumors, with the sensitivity of the murine Ptch1 promoter to methylation, and with the recently reported effect of demethylating agents on Ptch1 expression. These latter agents could be effective in treatment of, at least, some tumors associated with loss of PTCH1 function.
International Journal of Oncology 01/2006; 27(6):1567-75. · 2.40 Impact Factor
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Leszek Wojnowski,
Bettina Kulle,
Markus Schirmer,
Gregor Schlüter,
Albrecht Schmidt,
Albert Rosenberger,
Stefan Vonhof,
Heike Bickeböller,
Mohammad Reza Toliat,
Eun-Kyung Suk, [......],
Anke Kruger,
Silvia Seifert,
Marita Kloess, Heidi Hahn,
Markus Loeffler,
Peter Nürnberg,
Michael Pfreundschuh,
Lorenz Trümper,
Jürgen Brockmöller,
Gerd Hasenfuss
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ABSTRACT: A significant number of patients treated with anthracyclines develop cardiotoxicity (anthracycline-induced cardiotoxicity [ACT]), mainly presenting as arrhythmias (acute ACT) or congestive heart failure (chronic ACT). There are no data on pharmacogenomic predictors of ACT.
We genotyped participants of the German non-Hodgkin lymphoma study (NHL-B) who were followed up for the development of heart failure for a median of >3 years. Single-nucleotide polymorphisms (SNPs) were selected from 82 genes with conceivable relevance to ACT. Of 1697 patients, 55 developed acute and 54 developed chronic ACT (cumulative incidence of either form, 3.2%). We detected 5 significant associations with polymorphisms of the NAD(P)H oxidase and doxorubicin efflux transporters. Chronic ACT was associated with a variant of the NAD(P)H oxidase subunit NCF4 (rs1883112, -212A-->G; symbols with right-pointing arrows, as edited?' odds ratio [OR], 2.5; 95% CI, 1.3 to 5.0). Acute ACT was associated with the His72Tyr polymorphism in the p22phox subunit (rs4673; OR, 2.0; 95% CI, 1.0 to 3.9) and with the variant 7508T-->A (rs13058338; OR, 2.6; 95% CI, 1.3 to 5.1) of the RAC2 subunit of the same enzyme. In agreement with these results, mice deficient in NAD(P)H oxidase activity, unlike wild-type mice, were resistant to chronic doxorubicin treatment. In addition, acute ACT was associated with the Gly671Val variant of the doxorubicin efflux transporter multidrug resistance protein 1 (MRP1) (OR, 3.6; 95% CI, 1.6 to 8.4) and with the Val1188Glu-Cys1515Tyr (rs8187694-rs8187710) haplotype of the functionally similar MRP2 (OR, 2.3; 95% CI, 1.0 to 5.4). Polymorphisms in adrenergic receptors previously demonstrated to be predictive of heart failure were not associated with ACT.
Genetic variants in doxorubicin transport and free radical metabolism may modulate the individual risk to develop ACT.
Circulation 12/2005; 112(24):3754-62. · 14.74 Impact Factor
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ABSTRACT: Mutations in the Patched (Ptch1) gene are responsible for various familial and sporadic cancers. Ptch1(neo67/+) mice, in which exons 6 and 7 are deleted, show genetic background-dependent susceptibility to the development of muscle tumors resembling human rhabdomyosarcoma (RMS); BALB/c (BALB) is a susceptible strain whereas C57BL/6 (B6) shows resistance. A genome-wide linkage analysis was carried out using Ptch1(neo67/+)mice produced from B6 x (BALB x B6) backcrosses to identify loci involved in the control of RMS susceptibility. Quantitative trait locus mapping with the censored tumor latency time as the quantitative parameter was used to detect a significant RMS susceptibility modifier locus, Parms1 (Patched-Associated RMS 1), on chromosome 2 between D2Mit37 and D2Mit102 (LRS = 10). A Kaplan-Meier survival curve revealed that mice with the B6/BALB genotype develop tumors more frequently and much faster as compared to mice homozygous for the B6 allele (P = 0.02). Additional loci not reaching linkage significance were also detected for medulloblastoma resistance.
Genomics 12/2004; 84(5):853-8. · 3.02 Impact Factor
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ABSTRACT: Rhabdomyosarcoma (RMS) is a highly malignant tumor that is histologically related to skeletal muscle, yet genetic and molecular lesions underlying its genesis and progression remain largely unknown. In this study we have compared the molecular profiles of two different mouse models of RMS, each associated with a defined primary genetic defect known to play a role in rhabdomyosarcomagenesis in man. We report that RMS of heterozygous Patched1 (Ptch1) mice show less aggressive growth and a greater degree of differentiation than RMS of heterozygous p53 mice. By means of cDNA microarray analysis we demonstrate that RMS in Ptch1 mutants predominantly express a number of myogenic markers, including myogenic differentiation 1, myosin heavy chain, actin, troponin and tropomyosin, as well as genes associated with Hedgehog/Patched signaling like insulin-like growth factor 2, forkhead box gene Foxf1 and the growth arrest and DNA-damage-inducible gene Gadd45a. In sharp contrast, RMS in p53 mutants display higher expression levels of cell cycle-associated genes like cyclin B1, cyclin-dependent kinase 4 and the proliferation marker Ki-67. These results demonstrate that different causative mutations lead to distinct gene expression profiles in RMS, which appear to reflect their different biological characteristics. Our results provide a first step towards a molecular classification of different forms of RMS. If the described differences can be confirmed in human RMS our results will contribute to a new molecular taxonomy of this cancer, which will be critical for gene mutation- and expression-specific therapy.
Oncogene 12/2004; 23(54):8785-95. · 6.37 Impact Factor
