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ABSTRACT: Nested stromal epithelial tumor of the liver is a rare neoplasm of early childhood and adolescence with a characteristic nested morphology of spindle and epithelioid cells. Histogenesis and pathogenesis of this neoplasm are, however, still unclear. Because the characteristic nested morphology with spindle mesenchymal and epithelioid cells is suggestive of altered mesenchymal-epithelial transition and β-catenin mutations are rather common in other liver tumors such as hepatoblastomas, we investigated the β-catenin gene in 2 nested stromal epithelial tumors of the liver and analyzed additional factors involved in mesenchymal-epithelial transition, such as E-cadherin, vimentin, c-Met, TWIST, SNAIL, and SLUG by molecular genetic and immunohistochemical methods. Mutation analysis of both cases revealed large deletions in exon 3 of the β-catenin gene (155 and 228 base pairs), resulting in an accumulation of β-catenin in the cytoplasm and nuclei of tumor cells, as evidenced by immunohistochemistry. The expression of the mesenchymal-epithelial transition factors SNAIL, SLUG, TWIST, c-Met, vimentin, and β-catenin was generally increased, whereas E-cadherin was decreased. Morphological and immunohistochemical analysis, however, showed a variable expression pattern of various epithelial and mesenchymal markers both in the spindle and epithelioid cell compartments of the tumors, thus illustrating the transitional status of the tumor cells. In conclusion, our data clearly identify protein stabilizing mutations of the β-catenin gene as a common feature of nested stromal epithelial tumors of the liver, similarly as in hepatoblastomas. Therefore, nested stromal epithelial tumors of the liver may be regarded as a variant of hepatoblastoma, despite differing from it in clinical and morphological aspects. The characteristic epithelioid-spindle morphology along with the incomplete epithelial differentiation proposes impaired mesenchymal-epithelial transition as a possible pathogenetic mechanism of this rare tumor. However, because only 2 cases were studied, this hypothesis awaits further validation.
Human pathology 06/2012; 43(11):1815-27. · 3.03 Impact Factor
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ABSTRACT: Activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway plays a central role in the formation of hepatoblastoma (HB), the most common liver cancer in childhood. Blocking this pathway with specific mTOR inhibitors such as the immunosuppressant rapamycin is being currently tested for a variety of cancers. Here, we report that rapamycin treatment induced a significant dose-dependent inhibition of cell viability and promoted apoptosis in HB cells in vitro. Moreover, rapamycin inhibited AKT/mTOR signalling by dephosphorylation of the downstream target p70S6 kinase (p70S6K). Most importantly, treating subcutaneous HUH6 xenograft tumour bearing mice orally with 5mg/kg/day rapamycin for three weeks resulted in a striking reduction of tumour growth, as evidenced by reduced volume and weight, and moderately lowered tumour-specific alpha-fetoprotein (AFP) serum levels. The anti-tumourigenic effect was primarily ascribed to a significantly reduced proliferation rate upon p70S6K dephosphorylation, as microvascular density of rapamycin-treated compared to vehicle-treated tumours stayed grossly unchanged. Of uttermost clinical importance, we found no evidence for a feedback-loop activation of AKT in vivo. In conclusion, we demonstrate that rapamycin effectively inhibits HB growth both in vitro and in vivo by blocking AKT/mTOR signalling at the level of p70S6K and that rapamycin should be considered to treat HB patients especially those to be indicated for liver transplantation to benefit from its anti-tumourigenic and immunosuppressive properties.
European journal of cancer (Oxford, England: 1990) 01/2012; 48(15):2442-50. · 4.12 Impact Factor
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ABSTRACT: Accumulated experimental evidence indicates that Hedgehog (Hh) signaling regulates cell proliferation and specification in a variety of organs during embryonic development. However, abnormal activation of this pathway in postnatal tissues has been linked to a large number of human cancers. With respect to the liver, it is known that Hh signaling not only influences bipotential precursor cells capable of pancreas and liver development, but is also implicated in the pathogenesis of liver tumors such as hepatoblastoma, hepatocellular and cholangiocellular carcinoma, if aberrantly activated. Blockade of Hh signaling by several specific inhibitors has been proven to successfully inhibit tumor growth of various Hh-associated cancers in vitro and in preclinical mouse models, and recent clinical data suggest that the implementation of novel anticancer therapeutics based on Hh interference into commonly accepted regimens are within reach. Thus, it is highly probable that Hh targeted therapies could be used for the treatment of Hh-dependent liver cancers in the future.
Frontiers in bioscience (Scholar edition) 01/2012; 4:277-86.
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ABSTRACT: Searching for novel strategies to modulate apoptosis in neuroblastoma, we investigated the potential of the proteasome inhibitor bortezomib.
The effect of bortezomib on TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis signaling pathways was analyzed in neuroblastoma cell lines, primary neuroblastoma cultures, and in an in vivo model.
Bortezomib synergistically cooperates with TRAIL to induce apoptosis and to reduce colony formation of neuroblastoma cells (combination index: 0.5). Mechanistic studies reveal that bortezomib profoundly enhances TRAIL-induced cleavage of Bid into tBid, accumulation of tBid in the cytosol, and its insertion into mitochondrial membranes, pointing to a concerted effect on Bid cleavage (TRAIL) and stabilization of tBid (bortezomib), which links the death receptor to the mitochondrial pathway. In addition, bortezomib increases expression of p53 and Noxa. All these changes lead to increased activation of Bax and Bak, loss of the mitochondrial membrane potential, cytochrome c release, caspase activation, and caspase-dependent apoptosis on treatment with bortezomib and TRAIL. Knockdown of Bid, Noxa, or p53 significantly delays the kinetic of bortezomib- and TRAIL-induced apoptosis, whereas it does not confer long-term protection. By comparison, overexpression of Bcl-2, which simultaneously antagonizes tBid and p53, significantly inhibits bortezomib- and TRAIL-induced apoptosis and even rescues clonogenic survival. Importantly, bortezomib and TRAIL act in concert to trigger apoptosis and to suppress tumor growth in patient-derived primary neuroblastoma cells and in an in vivo model of neuroblastoma.
Bortezomib represents a promising new approach to prime neuroblastoma cells toward TRAIL, which warrants further investigation.
Clinical Cancer Research 04/2011; 17(10):3204-18. · 7.74 Impact Factor
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ABSTRACT: Overexpression of insulin-like growth factor 2 (IGF2), an imprinted gene located on chromosome 11p15, has been reported as a characteristic feature in various embryonal tumors, including Wilms tumor (WT). Recent studies specified loss of imprinting (LOI) in a differential methylated region (DMR) of the IGF2/H19 cluster or loss of heterozygosity (LOH), respectively, uniparental disomy (UPD) being responsible for this overexpression. However, the role of other imprinted genes in the genesis of WT is still unknown. In the current study, we analyzed transcriptional activity of the imprinted genes IGF2, H19, NNAT, DLK1, RTL1, MEG3, and MEST as well as the methylation status of the DMR of the IGF2/H19 cluster in a panel of 32 WTs. Except for H19, we detected massive overexpression of all genes in the majority of WTs compared to normal renal tissue, which was most prominent for the paternally expressed genes IGF2, NNAT, and MEST. Alterations of the H19DMR were found in two-thirds of the WTs. Moreover, we have seen a strong correlation between the transcriptional activity of IGF2, NNAT and MEST and LOI/LOH of H19DMR, which was inverse for H19. Expression of DLK1, RTL1 and MEG3 does not correlate with LOI/LOH of H19DMR. Altogether, our findings suggest that over-expression of imprinted genes is common in WTs and correlates at least for some imprinted genes with LOI of H19DMR. Thus, it may be speculated that alterations of the DNA modification machinery drive erroneous setting of methylation marks in imprinting regions throughout the genome, which leads to the concomitant activation of imprinted genes in blastomagenesis.
Oncology Reports 03/2011; 25(3):817-23. · 1.84 Impact Factor
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ABSTRACT: MicroRNAs (miRNAs) are well-known regulators of proliferation, apoptosis, and differentiation and are recognized to play an important role in the development of cancers. Here we aimed to identify the functional contribution of miRNAs to the biology of hepatoblastoma (HB), the most common malignant liver tumor in childhood. As overexpression of the oncogene PLAG1 (pleomorphic adenoma gene 1) is a characteristic phenomenon in HB, we used RNA interference and subsequent miRNA array analysis to identify miR-492 as most strongly influenced by PLAG1. We provide novel experimental evidence that miR-492 can originate from the coding sequence of the HB marker gene keratin 19 (KRT19). In agreement with these in vitro observations, significantly elevated levels of coexpressed KRT19 and miR-492 were particularly found in metastatic HB tumor samples. Stable overexpression of miR-492 in HB cell clones served to identify a broad range of differentially expressed transcripts, including several candidate targets of miR-492 predicted by computational algorithms. Among those the liver enzyme BAAT showed significant association with miR-492 expression in HB tumor samples. Conclusion: A close functional relationship between KRT19 and miR-492 was identified that may play an important role in the progression of malignant embryonal liver tumors. Additionally, miR-492 and its associated targets might serve as new HB biomarkers of clinical utility and could assist to explore targeted therapies, especially in metastatic HB with a poor prognosis. (HEPATOLOGY 2011)
Hepatology 02/2011; 53(3):833 - 842. · 11.66 Impact Factor
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ABSTRACT: Hepatoblastoma (HB) is a rare malignancy of the liver affecting mainly children between 6 months and 3 years of age. As this
tumor recapitulates the phenotypic and biological features of the developing liver, many processes known to be essential in
early embryonic development are implicated in the genesis of HB. This chapter describes the molecular mechanisms by which
HB is thought to develop and progress, including alterations of the Wnt and hedgehog signaling pathways, the insulin-like
growth factor axis, the hepatocytes growth factor/c-Met pathway, and epigenetically regulated genes. How this knowledge is
currently translated into clinics is furthermore discussed, with a focus on establishing diagnostic tools, systems for predicting
prognosis, response to therapy, and potential novel therapeutic strategies.
Hepatoblastoma (HB) is a rare malignancy of the liver affecting mainly children between 6 months and 3 years of age. As this
tumor recapitulates the phenotypic and biological features of the developing liver, many processes known to be essential in
early embryonic development are implicated in the genesis of HB. This chapter describes the molecular mechanisms by which
HB is thought to develop and progress, including alterations of the Wnt and hedgehog signaling pathways, the insulin-like
growth factor axis, the hepatocytes growth factor/c-Met pathway, and epigenetically regulated genes. How this knowledge is
currently translated into clinics is furthermore discussed, with a focus on establishing diagnostic tools, systems for predicting
prognosis, response to therapy, and potential novel therapeutic strategies.
01/2011: pages 27-42;
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ABSTRACT: MicroRNAs (miRNAs) are well-known regulators of proliferation, apoptosis, and differentiation and are recognized to play an important role in the development of cancers. Here we aimed to identify the functional contribution of miRNAs to the biology of hepatoblastoma (HB), the most common malignant liver tumor in childhood. As overexpression of the oncogene PLAG1 (pleomorphic adenoma gene 1) is a characteristic phenomenon in HB, we used RNA interference and subsequent miRNA array analysis to identify miR-492 as most strongly influenced by PLAG1. We provide novel experimental evidence that miR-492 can originate from the coding sequence of the HB marker gene keratin 19 (KRT19). In agreement with these in vitro observations, significantly elevated levels of coexpressed KRT19 and miR-492 were particularly found in metastatic HB tumor samples. Stable overexpression of miR-492 in HB cell clones served to identify a broad range of differentially expressed transcripts, including several candidate targets of miR-492 predicted by computational algorithms. Among those the liver enzyme BAAT showed significant association with miR-492 expression in HB tumor samples. CONCLUSION: A close functional relationship between KRT19 and miR-492 was identified that may play an important role in the progression of malignant embryonal liver tumors. Additionally, miR-492 and its associated targets might serve as new HB biomarkers of clinical utility and could assist to explore targeted therapies, especially in metastatic HB with a poor prognosis.
Hepatology 12/2010; 53(3):833-42. · 11.66 Impact Factor
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Sebastian Schroepf, Roland Kappler,
Stephan Brand,
Christine Prell,
Peter Lohse,
Jürgen Glas,
Eva Hoster,
Johanna Helmbrecht,
Antje Ballauff,
Michael Berger,
Dietrich von Schweinitz,
Sibylle Koletzko,
Martin Lacher
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ABSTRACT: Inflammatory bowel disease (IBD) is a polygenetic disorder. Our group previously showed that a variant within the CXCL9 gene is associated with pediatric Crohn's disease. As CXCL9, CXCL10, and CXCL11 are the 3 ligands to the receptor CXCR3, the aim of this study was to investigate the colonic transcriptional activity of the CXCR3 axis and to perform SNP genotyping of a CXCL11 polymorphism in a large pediatric and adult IBD cohort.
mRNA expression of CXCR3, CXCL9, CXCL10, CXCL11, and IL8 was analyzed in colonic biopsies using real-time PCR. CXCL11 rs6817952 nucleotide substitution was determined in 501 German individuals with IBD (336 CD, 165 UC) including 258 children and 243 adults as well as in 231 controls by a TaqMan SNP genotyping assay.
CXCR3 axis genes were significantly overexpressed in inflamed colonic tissue of pediatric CD and UC patients. The prevalence of hetero- and homozygous variants of the rs6817952 genotype was higher in pediatric but not in adult CD patients compared with that in controls (P = 0.04). Moreover, carriers of the hetero- and homozygous genotype variants of rs6817952 were at increased risk for UC in all age groups (P = 0.009).
Our study provides evidence of the significant overexpression of the CXCR3 axis in active IBD, suggesting it has a role in IBD pathogenesis. The rs6817952 A variant is a risk allele for pediatric CD and UC in all age groups. Therapeutic studies will have to show whether the blockade of chemokine receptors such as CXCR3 can modulate intestinal inflammation in a clinical application.
Inflammatory Bowel Diseases 11/2010; 16(11):1882-90. · 4.86 Impact Factor
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Martin Lacher,
Guido Fitze,
Johanna Helmbrecht,
Sebastian Schroepf,
Michael Berger,
Peter Lohse,
Sibylle Koletzko,
Antje Ballauff,
Veit Grote,
Jan Goedeke,
Dietrich von Schweinitz, Roland Kappler
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ABSTRACT: BACKGROUD/PURPOSE: Hirschsprung-associated enterocolitis (HAEC) represents a cause for significant pre- and postoperative morbidity and mortality in Hirschsprung disease (HD). Although multiple studies on HAEC have been performed and several mechanisms have been presumed, the pathogenesis of this condition remains unclear. As changes in colonic mucosal defense are key factors suggested in both Crohn's disease (CD) and HAEC pathogenesis, the aim of the current study was to investigate genetic alterations in the most important susceptibility gene for Crohn's enterocolitis (NOD2) to see whether carriers of polymorphisms within the NOD2 gene are predisposed to the development of HAEC.
Genotyping for the NOD2 variants in exon 4 (p.Arg702Trp [rs2066844]), exon 8 (p.Gly908Arg [rs2066845]), and exon 11 (p.1007fs [rs2066847]) was performed in 52 white children with HD (41 boys, 11 girls), 152 healthy controls, and 152 children with CD (onset of disease <17 years; mean, 11.8 years). Seventeen patients with HD (32.7%) were carriers of a RET germline mutation, 35 children (67.3%) had short segment disease, and 17 (32.7%) had long segment disease.
Ten children (19.2%) with HD were heterozygous carriers of at least one NOD2 variant vs 17 (11.2%) in the healthy control group and 69 (45.4%) in the CD cohort. Hirschsprung-associated enterocolitis was observed in 7 children (13.5%), with 4 having short segment HD and 3 with long segment HD; but none of them were carriers of NOD2 variants.
Our study shows that NOD2 variants described to be causatively associated with CD do not predispose to the development of HAEC. As data on the molecular basis of HAEC are limited, the distinct mechanisms involved in the pathogenesis of this complication remain unclear.
Journal of Pediatric Surgery 09/2010; 45(9):1826-31. · 1.45 Impact Factor
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Martin Lacher,
Johanna Helmbrecht,
Sebastian Schroepf,
Sibylle Koletzko,
Antje Ballauff,
Martin Classen,
Holm Uhlig,
Jochen Hubertus,
Dominik Hartl,
Peter Lohse,
Dietrich von Schweinitz, Roland Kappler
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ABSTRACT: Three common mutations of the NOD2/CARD15 gene have been associated with Crohn disease (CD), ileal disease location, and fibrostenotic behavior. The aim of this study was to investigate the effect of these mutations on disease manifestation and the risk of surgery in a cohort of German childhood-onset CD patients.
Genotyping for the NOD2 mutations p.Arg702Trp, p.Gly908Arg, and p.1007fs was performed in 171 CD children (onset of disease <17 years; mean 11.8 years) and in 253 controls. NOD2 mutation status was correlated with the need for surgery during childhood.
Seventy-eight children (45.6%) were carriers of at least 1 NOD2 mutation versus 36 (14.2%) in the control group (P < .0001). NOD2 mutations were highly associated with CD and stricturing behavior (P < .0001), with the p.1007fs mutation also conferring a risk for isolated ileal disease (P = .003). Thirty-two children (18.7%) needed an intestinal resection with a significant association between the need of surgery and NOD2 carrier status. Surgery occurred at an earlier stage of disease in children with p.1007fs mutations.
In children with pediatric-onset CD, the need for surgical therapy younger than 17 years is associated with the NOD2 genotype. Genetic testing therefore may identify children with CD who are at risk.
Journal of Pediatric Surgery 08/2010; 45(8):1591-7. · 1.45 Impact Factor
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ABSTRACT: Bone morphogenetic proteins (BMP) have been shown to affect tumorigenesis in a variety of tumors. Quantitative PCR analysis revealed down-regulation of BMP2 and BMP5 in tissue samples from adrenocortical carcinoma and adrenocortical tumor cell lines compared with normal adrenal glands. Integrity of BMP-dependent pathways in these cell lines could be shown by activation of the Smad1/5/8 pathway with subsequent increase of ID protein expression upon incubation with BMP2 or BMP5. On a functional level, BMP treatment resulted in inhibition of cell proliferation and viability in a dose- and time-dependent manner. This growth inhibitory effect was associated with BMP-dependent reduction of AKT phosphorylation under baseline conditions and under insulin-like growth factor costimulation. Furthermore, steroidogenic function, including melanocortin-2 receptor and steroidogenic enzyme expressions, was profoundly reduced. In vitro demethylation treatment and overexpression of GATA6 resulted in reactivation of BMP-dependent pathways with concomitant modulation of steroidogenesis. Taken together, we show that loss of expression of members of the BMP family of ligands is a common finding in adrenocortical tumors and we provide evidence that BMP-dependent pathways are likely to be involved in the modulation of the malignant and functional phenotype of adrenocortical cancer cells.
Cancer Research 08/2009; 69(14):5784-92. · 7.86 Impact Factor
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ABSTRACT: Genome-wide association studies have described an association of the ATG16L1 (autophagy 16-like 1) gene rs2241880 variant with Crohn's disease (CD). Therefore, we evaluated this polymorphism in early-onset CD in 152 children and 253 controls and for the first time determined ATG16L1 colonic expression in German CD children.
Investigation of rs2241880 allele frequencies using a predesigned single nucleotide polymorphism genotyping assay. Analysis of digenic epistasis between rs2241880 and the three common nucleotide-binding oligomerization domain containing two (NOD2/CARD15) mutations. Determination of ATG16L1 gene expression in large-bowel biopsies of selected patients and controls using real-time polymerase chain reaction.
The rs2241880G risk allele frequency was higher in CD compared with controls (63.0% vs. 47.4%; p = 0.0002). No epistasis between NOD2/CARD15 mutations and rs2241880 was observed; however, carriers of both variants had significantly increased disease risk. Transcriptional analysis did not reveal over- or underexpression of ATG16L1 in CD patients compared with controls.
We confirmed the association of CD with ATG16L1 rs2241880 variant in early-onset CD. As no epistatic interaction with three common NOD2/CARD15 mutations was observed, the p.Thr300Ala substitution is an independent risk factor for paediatric CD and supports the role for autophagy in disease pathogenesis.
Acta Paediatrica 08/2009; 98(11):1835-40. · 2.07 Impact Factor
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ABSTRACT: Studies in adults characterized the role of the pregnane X receptor (PXR) in the pathophysiology of inflammatory bowel disease (IBD) with conflicting results; pediatric studies are still lacking.
Genotyping for the -25385C/T polymorphism of the PXR gene in 187 white children with IBD and 185 controls. Determination of colonic PXR expression in selected patients with IBD.
Minor allele frequency was seen in 35.6% patients with IBD and 40.5% controls (P = 0.174), although no significant differences were seen between the genotypes (P = 0.366). PXR was underexpressed in colonic tissue of 7 out of 11 Crohn disease and in 4 out of 5 patients with ulcerative colitis.
We could not confirm an association of the -25385C/T polymorphism in pediatric patients with IBD.
Journal of pediatric gastroenterology and nutrition 06/2009; 49(1):147-50. · 2.18 Impact Factor
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ABSTRACT: Patients with nevoid basal cell carcinoma syndrome carry germline mutations in the tumor suppressor gene Patched 1 (PTCH1) and are predisposed to develop basal cell carcinoma (BCC), medulloblastoma (MB), and rhabdomyosarcoma (RMS). These tumors are also present in the murine model for Ptch1 deficiency, the Ptch1neo67/+ mouse. Previous studies, including those from our laboratory, have shown that the forkhead box transcription factor Foxf1 is highly expressed in RMS of human and murine origin. We report on a more common role of Foxf1 in Ptch1-associated tumorigenesis, since we found a striking up-regulation of Foxf1 expression in Ptch1-associated BCC and MB compared with the respective non-neoplastic tissue. This overexpression was accompanied by increased levels of the Hedgehog target gene Gli1 as well as the putative Foxf1 targets Bmi1 and Notch2 in these tumors. We also describe a striking Foxf1 activation in Ptch1 null embryos. In contrast, basal expression levels of Foxf1, Gli1, Bmi1 and Notch2 were detected in a variety of adult mouse tissues, such as liver, kidney, spleen, lung, heart and brain. In conclusion, our study suggests that Foxf1 expression is characteristically up-regulated in tumors with a constitutively activated Hedgehog signaling pathway thereby defining a key role for Foxf1 in Hedgehog-associated tumorigenesis.
International Journal of Molecular Medicine 01/2009; 22(6):787-92. · 1.98 Impact Factor
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ABSTRACT: Neuroblastomas (NBs) are frequent solid tumors in childhood for which no specific genetic marker linked to their development has been identified to date. PHOX2b, which regulates the autonomic neuron development, has been associated with the development of autonomic diseases, and has been considered a potential candidate gene for neural crest-derived tumors such as NB. To ascertain the role of the PHOX2b gene in NB development, we have sequenced the complete PHOX2b coding region in tumors from 69 patients with sporadic NB, while 130 blood donors served as negative controls and 9 NB cell lines as positive controls. We found a missense deletion in exon 3 in a cell line. A further silent mutation in exon 3 (c.870C>A) was observed in 3 tumors but in none of the controls. A new polymorphism in intron 1 (IVS1-114 G>A) was observed in 31 tumor samples (44.9%) and in 68 controls (52.3%). We did not find any conclusive association of the polymorphisms or mutations in PHOX2b with the development of NB, although the large confidence intervals neither substantiate nor exclude a role for this gene in the tumor etiology.
Journal of Pediatric Hematology/Oncology 10/2008; 30(10):728-32. · 1.16 Impact Factor
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ABSTRACT: Recent evidence has indicated that Hedgehog (Hh) signaling significantly contributes to liver development and regeneration and that activation of the pathway may contribute to growth of hepatocellular carcinoma (HCC) in adults. However, the role of Hh signaling in pediatric liver tumors remains to be elucidated. In this study, we show that Hh signaling is activated in hepatoblastoma (HB), the most common liver tumor in childhood, with most occurrences before the age of 3 years. The Hh target genes glioma-associated oncogene homolog 1 (GLI1) and Patched (PTCH1) showed increased transcript levels in 65% and 30% of HB samples, respectively, compared with normal liver tissues. Most interestingly, the gene encoding the hedgehog interacting protein (HHIP) is transcriptionally silenced by cytosine-phospho-guanosine (CpG) island promoter hypermethylation in 26% of HB cases and treatment with the DNA-demethylating agent 5-aza-2'-deoxycytidine partially restored HHIP expression. Blocking Hh signaling with the antagonist cyclopamine had a strong inhibitory effect on cell proliferation of HB cell lines with an activated pathway. We further demonstrate that this decrease in cell viability is caused by a massive induction of apoptosis, as shown by morphological changes and phosphatidylserine membrane asymmetry. In cyclopamine-exposed HB cells, caspase 3 and poly(adenosine diphosphate-ribose) polymerase proteins were specifically activated by their proteolytic cleavage. Conclusion: This study demonstrates, for the first time, the frequent occurrence of GLI1 and PTCH1 overexpression and HHIP promoter methylation in early childhood HB, thus indicating a key role for Hh signaling activation in the malignant transformation of embryonal liver cells.
Hepatology 10/2008; 49(2):482-90. · 11.66 Impact Factor
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ABSTRACT: Genetic and environmental factors contribute to the etiopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). To identify new susceptibility genes, we determined the mRNA expression level of 88 genes from different biological contexts on colonic biopsies of CD and UC patients. We show that CXCL9 was overexpressed in colonic tissue of 3/5 CD and 3/3 UC patients compared to healthy controls. SNP genotyping for the 77147452G-->A polymorphism of the CXCL9 gene on 114 pediatric IBD patients and 120 ethnically matched unaffected adults detected a minor allele frequency of 20.3% in CD patients compared to 31.3% in controls (p=0.016). Strikingly, children with homozygosity for the wild-type allele had a significant earlier onset of CD than heterozygous individuals (11.1 versus 13.8 years). This is the first report of inverse association of the CXCL9 77147452G-->A polymorphism with pediatric CD. Our data may contribute to a better understanding of the pathophysiology underlying CD.
Biochemical and Biophysical Research Communications 11/2007; 363(3):701-7. · 2.48 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: Dermoids belong to the group of developmental cysts and arise from germ cells. Studies on these tumors may therefore increase our understanding of normal germ cell development within different environments and cell lines derived from these lesions may also constitute an important vehicle for studying neoplasia and differentiation. Recently, we investigated the status of the PTCH1 locus in a large set of sporadic non-inflammatory, developmental cystic lesions. Our data showed allelic loss of microsatellite markers in close vicinity to the PTCH1 locus in both odontogenic keratocysts and dentigerous cysts as well as in ovarian dermoid cysts (ODC). In this study, we closely examined the status of the PTCH1 gene in ODCs. Although about 25% of cysts demonstrated LOH at the PTCH1 locus, no nonsense or missense mutations in the coding region of PTCH1 were detected in genomic DNA isolated from any of the ODCs examined by direct sequencing. Staining with PTCH1 and GLI1 antibodies showed that proteins were present in virtually all epithelial linings, with variable staining intensity not correlated with LOH and generally weaker for GLI1. However, cDNA microarray analysis performed on cell lines derived from ODCs did not show any significant alteration in the expression of the analyzed target genes of PTCH1 signaling in any of the cell lines examined, except for CyclinD1 (and several other genes generally not associated with PTCH1 signaling).
International Journal of Molecular Medicine 12/2004; 14(5):793-9. · 1.98 Impact Factor
