Project description:Desmoid tumors (also called deep or aggressive fibromatoses) are potentially life-threatening fibromatous lesions. Hereditary desmoid tumors arise in individuals affected by either familial adenomatous polyposis (FAP) or hereditary desmoid disease (HDD) carrying germline mutations in APC. Most non-FAP (sporadic) desmoids carry somatic mutations in the beta-catenin gene. Previous studies identified losses on 5q and 6q, and gains on 8q and 20q as recurrent genetic changes in desmoids. However, virtually all genetic changes were derived from sporadic tumors. To investigate the somatic alterations in FAP-associated desmoids and to compare them with changes occurring in sporadic tumors, we analyzed 17 FAP-associated and 38 sporadic desmoids for copy number abnormalities (CNAs) by means of array comparative genomic hybridization and multiple ligation-dependent probe amplification. Overall, the desmoids displayed only a limited number of genetic changes, occurring in 44% of cases. Common gains at 8q (7%) and 20q (5%) were almost exclusively found in sporadic tumors. Frequent common losses were observed within a 700 kb region at 5q22.2, comprising the APC gene (11%), in a 2 Mb region at 6p21.2-p21.1 (15%), and in a relatively large region at 6q15-q23.3 (20%). The FAP-associated desmoids displayed a significantly higher frequency of CNAs (59%) than the sporadic tumors (37%). As predicted by the APC germline mutations among these patients, a relatively high percentage (29%) of the FAP-associated desmoids showed loss of the APC region at 5q22.2, which was infrequently (3%) seen among sporadic tumors. Our data suggest that loss of region 6q15-q16.2 is an important event in FAP-associated as well as sporadic desmoids, most likely of relevance for desmoid tumor progression. Fifty-three fresh frozen tumor samples were collected at four institutes: Center for Human Genetics, University of Leuven, Belgium (21 samples); INSERM U674, Fondation Jean Dausset-CEPH, Paris, France (15 samples); Hospital for Sick Children, Toronto, Canada (13 samples); and the Italian Registry of Hereditary Colorectal Cancer (Dr. L. Bertario, 4 samples). In addition, DNA of two fresh frozen tumors, HDD-H of patient III:2 and HDD-I of patient III:6, of our hereditary desmoids disease (HDD) family10 was available (Table 1). In this family, multifocal desmoid tumors were inherited as an autosomal dominant trait, and HDD segregated with a 3' APC mutation at codon 1924. For the latter reason, they were classified as FAP tumors in this study. Three FAP tumors were derived from a family with 2 relatives in the study (D15-1 and D15-2 of a male patient and D16 of his sister). Colonic polyposis had been observed in 12 FAP patients, not in the 2 HDD-FAP patients and not in patient D15. The germline APC mutation was known in 14 of 17 FAP-associated tumors. In 28 of 38 non-FAP-associated desmoid tumors, the beta-catenin gene (CTNNB1) mutation in exon 3 was known and in 1 of 38 tumors an APC mutation was present (data not shown). The remaining tumors were characterized as FAP or non-FAP based on clinical data and positivity of tumor cells upon immunostaining for beta-catenin. DNA was extracted from the tumor samples according to standard methods.
Project description:Desmoid tumors (also called deep or aggressive fibromatoses) are potentially life-threatening fibromatous lesions. Hereditary desmoid tumors arise in individuals affected by either familial adenomatous polyposis (FAP) or hereditary desmoid disease (HDD) carrying germline mutations in APC. Most non-FAP (sporadic) desmoids carry somatic mutations in the beta-catenin gene. Previous studies identified losses on 5q and 6q, and gains on 8q and 20q as recurrent genetic changes in desmoids. However, virtually all genetic changes were derived from sporadic tumors. To investigate the somatic alterations in FAP-associated desmoids and to compare them with changes occurring in sporadic tumors, we analyzed 17 FAP-associated and 38 sporadic desmoids for copy number abnormalities (CNAs) by means of array comparative genomic hybridization and multiple ligation-dependent probe amplification. Overall, the desmoids displayed only a limited number of genetic changes, occurring in 44% of cases. Common gains at 8q (7%) and 20q (5%) were almost exclusively found in sporadic tumors. Frequent common losses were observed within a 700 kb region at 5q22.2, comprising the APC gene (11%), in a 2 Mb region at 6p21.2-p21.1 (15%), and in a relatively large region at 6q15-q23.3 (20%). The FAP-associated desmoids displayed a significantly higher frequency of CNAs (59%) than the sporadic tumors (37%). As predicted by the APC germline mutations among these patients, a relatively high percentage (29%) of the FAP-associated desmoids showed loss of the APC region at 5q22.2, which was infrequently (3%) seen among sporadic tumors. Our data suggest that loss of region 6q15-q16.2 is an important event in FAP-associated as well as sporadic desmoids, most likely of relevance for desmoid tumor progression.
Project description:Desmoid tumors (DT) are rare, benign, fibroblastic neoplasm with challenging histological diagnosis. DTs can occur sporadically or associated with the familial adenomatous polyposis coli (FAP). Most sporadic DTs are associated with β-catenin gene (CTNNB1) mutations, while mutated APC gene causes FAP disease. MicroRNAs (miRNAs) are involved in many human carcinogenesis. The miRNA profile was analyzed by microarray in formalin-fixed, paraffin-embedded (FFEP) specimens of 12 patients (8 sporadic, 4 FAP-associated) and 4 healthy controls. One hundred and one miRNAs were dysregulated, of which 98 miRNAs in sporadic DTs, 8 in FAP-associated DTs, 5 were shared by both tumors. Twenty-six miRNAs were then validated by RT-qPCR in 23 sporadic and 7 FAP-associated DT samples matched with healthy controls. The same qPCR method was used to evaluate the CTNNB1 mutational status in sporadic DTs. The correlation between sporadic DTs and miRNA expression showed that miR-21-3p increased in mutated versus wild-type DTs, while miR-197-3p was decreased. The mRNA expression of Tetraspanin3 and Serpin family A member 3, miR-21-3p targets, and L1 Cell Adhesion Molecule, miR-197-3p target, was also evaluated. CTNNB1 mutations associated to miRNA dysregulation could help histological diagnosis of sporadic DTs and could affect the genesis and the progression of this disease.
Project description:Unsupervised clustering of desmoid tumors and normal mesenchymal tissues was performed using henes associated with HIF1 activity. This accurately distiguished neoplastic tissues from normal controls The study sought to identify genes differentially expressed in desmoid-type fibromatosis as opposed to normal mesenchymal tissues. We noted that beta-catenin, the central driver in desmoid-type fibromatosis, appeared to regulate HIF1 signaling in in vitro studies. Genes associated with HIF1 and angiogenesis pathways were then used to perform unsupervised clustering on desmoid tumors and normal mesenchymal tissues. The genes accurately differentiated neoplastic and normal samples.
Project description:Purpose: This study sought to identify signaling pathways that modulate β-catenin function in desmoid cells, affecting natural history and sorafenib response. Experimental Design: In vitro experiments utilized primary desmoid cell lines to examine interaction of β-catenin signaling with other pathways. Relevance of in vitro results was assessed in surgical specimens and Alliance trial A091105 correlative biopsies. Results: CTNNB1 knockdown inhibited hypoxia-regulated gene expression in vitro and reduced levels of HIF1α. Expression of hypoxia-associated genes clustered desmoids separately from normal mesenchymal tissue. ChIP-seq identified ABL1 as a β-catenin transcriptional target that modulated HIF1α protein expression and desmoid cell proliferation. Abrogation of either CTNNB1 or HIF1 inhibited the ability of desmoid cells to induce VEGFR2 phosphorylation and tube formation in endothelial cell co-cultures. Sorafenib inhibited this activity directly but also reduced HIF1α protein expression and c-Abl activity while inhibiting PDGFRβ signaling in desmoid cells. Conversely, c-Abl activity and desmoid cell proliferation were positively regulated by activation of PDGF signaling. Reduction in PDGFRβ and c-Abl phosphorylation was commonly observed in samples from patients after treatment with sorafenib; baseline samples in patients with greater drug response tended to have higher baseline PDGFRβ/c-Abl pathway activation. Conclusions: The β-catenin transcriptional target ABL1 is necessary for proliferation and maintenance of HIF1α protein expression in desmoid cells. Regulation of c-Abl activity by PDGF signaling and targeted therapies modulates desmoid cell proliferation, thereby suggesting a reason for variable biologic behavior between tumors, a mechanism for sorafenib activity in desmoids, and markers predictive of outcome in patients.
Project description:Desmoids tumors (DTs) are rare mesenchymal infiltrative lesions that exhibit high risk of local recurrence despite surgery with negative margins. Mutations in CTNNB1 gene encoding for β-catenin are typically carried by most sporadic DTs but the evidences in support to the clinical/biological role of these mutations are contrasting. Our work is the first study specifically investigating if mutation type could influence the stability of the β-catenin structure, its affinity for α-catenin, as well as the pattern of gene expression and could in turn guide the behavior of the disease.
Project description:The mechanisms underlying oncogenesis in desmoid-type fibromatosis are poorly understood. This project sought to understand how β-catenin may function to promote desmoid formation and how external signaling by PDGFRβ modulates this activity. To examine this question, RNA-seq was performed on CTNNB1 knock-downs. Gene set enrichment analysis suggested that the oncogene controlled HIF1 and angiogenesis pathways; expression of related genes accurately differentiated desmoids analyzed by U133A array from normal mesenchymal tissues. We identified c-ABL as a direct transcriptional target of β-catenin that promoted HIF1α expression in desmoid cells. We also noted that c-ABL activity was enhanced by PDGFRβ. PDGFRβ enhanced desmoid cell proliferation and c-ABL was necessary for desmoid proliferation. To identify potential markers of PDGFRβ/c-ABL activity in vivo, we assessed RNA-seq of desmoid cells treated with PDGF-BB. ERG1 transcription was highly upregulate and IHC of ERG1 was subsequently used to assess outcomes in desmoid patients with biopsies available for testing.
Project description:The mechanisms underlying oncogenesis in desmoid-type fibromatosis are poorly understood. This project sought to understand how β-catenin may function to promote desmoid formation and how external signaling by PDGFRβ modulates this activity. To examine this question, RNA-seq was performed on CTNNB1 knock-downs. Gene set enrichment analysis suggested that the oncogene controlled HIF1 and angiogenesis pathways; expression of related genes accurately differentiated desmoids analyzed by U133A array from normal mesenchymal tissues. We identified c-ABL as a direct transcriptional target of β-catenin that promoted HIF1α expression in desmoid cells. We also noted that c-ABL activity was enhanced by PDGFRβ. PDGFRβ enhanced desmoid cell proliferation and c-ABL was necessary for desmoid proliferation. To identify potential markers of PDGFRβ/c-ABL activity in vivo, we assessed RNA-seq of desmoid cells treated with PDGF-BB. ERG1 transcription was highly upregulate and IHC of ERG1 was subsequently used to assess outcomes in desmoid patients with biopsies available for testing.
Project description:The majority of sporadic colorectal cancer cases are initiated by mutations in the APC tumor suppressor gene leading to constitutive activation of the Wnt/b-catenin signaling pathway and adenoma formation. Several pre-clinical models carrying germline mutations in the endogenous mouse Apc tumor supressor gene have been generated and their phenotype characterized. The predisposition of these mouse models to multiple intestinal adenomas closely resembles the FAP phenotype at the molecular, cellular and phenotypic level and may prove valuable to elucidate the molecular and cellular mechanisms underlying colorectal tumorigenesis. The goal of this study is to establish an expression signature characteristic of intestinal tumors characterized by the inactivation of Apc. Experiment Overall Design: We have compared 3 intestinal tumor samples collected from the mouse model Apc1638N against 2 normal intestinal samples collected from wild type C57Bl6/J animals. In both cases only epithelial cells were used for the signature since we have collected our samples were laser capture microdissected.