Project description:Mice with thyroid-specific expression of oncogenic BRAF (Tg-Braf) develop papillary thyroid cancers (PTC) that are locally invasive and have well-defined foci of poorly differentiated thyroid carcinoma (PDTC). To investigate the PTC-PDTC progression, we performed a microarray analysis using RNA from paired samples of PDTC and PTC collected from the same animals by laser capture microdissection. Analysis of 8 paired samples revealed a profound deregulation of genes involved in cell adhesion and intracellular junctions, with changes consistent with an epithelial-mesenchymal transition (EMT). This was confirmed by IHC, as vimentin expression was increased and E-cadherin lost in PDTC compared to adjacent PTC. Moreover, PDTC stained positively for phospho-Smad2, suggesting a role for transforming growth factor-beta (TGFbeta) in mediating this process. Accordingly, TGFbeta induced EMT in primary cultures of thyroid cells from Tg-Braf mice, whereas wild-type thyroid cells retained their epithelial features. TGFbeta-induced Smad2 phosphorylation, transcriptional activity and induction of EMT required MAPK pathway activation in Tg-Braf thyrocytes. Hence, tumor initiation by oncogenic BRAF renders thyroid cells susceptible to TGFbeta-induced EMT, through a MAPK-dependent process. Comparing the transcription profiles of 8 pairs of murine poorly differentiated thyroid cancer and papillary thyroid cancer collected from the same animals by laser capture microdissection. Co-hybridizations were done in triplicate with a single dye flip.
Project description:We compared the expression profiles of papillary thyroid tumors from the Chernobyl Tissues Bank (CTB) with tumors from French patients with no history of exposure to radiations. Keywords: papillary thyroid cancer vs. patient-matched healthy adjacent thyroid thyroid papillary cancer vs. patient-matched adjacent nontumor thyroid tissues. -14 tumors from France -12 tumors from Ukraine
Project description:Mice with thyroid-specific expression of oncogenic BRAF (Tg-Braf) develop papillary thyroid cancers (PTC) that are locally invasive and have well-defined foci of poorly differentiated thyroid carcinoma (PDTC). To investigate the PTC-PDTC progression, we performed a microarray analysis using RNA from paired samples of PDTC and PTC collected from the same animals by laser capture microdissection. Analysis of 8 paired samples revealed a profound deregulation of genes involved in cell adhesion and intracellular junctions, with changes consistent with an epithelial-mesenchymal transition (EMT). This was confirmed by IHC, as vimentin expression was increased and E-cadherin lost in PDTC compared to adjacent PTC. Moreover, PDTC stained positively for phospho-Smad2, suggesting a role for transforming growth factor-beta (TGFbeta) in mediating this process. Accordingly, TGFbeta induced EMT in primary cultures of thyroid cells from Tg-Braf mice, whereas wild-type thyroid cells retained their epithelial features. TGFbeta-induced Smad2 phosphorylation, transcriptional activity and induction of EMT required MAPK pathway activation in Tg-Braf thyrocytes. Hence, tumor initiation by oncogenic BRAF renders thyroid cells susceptible to TGFbeta-induced EMT, through a MAPK-dependent process.
Project description:We compared the expression profiles of papillary thyroid tumors from the Chernobyl Tissues Bank (CTB) with tumors from French patients with no history of exposure to radiations. Keywords: papillary thyroid cancer vs. patient-matched healthy adjacent thyroid
Project description:We profiled the gene expression of 11 anaplastic thyroid carcinomas (ATC), 49 papillary thyroid carcinomas (PTC) and 45 normal thyroids (N) We hibridized a series of anaplastic thyroid carcinomas (ATC) and papillary thyroid carcinomas (PTC) onto Affymetrix U133 Plus 2.0 arrays. ATCs were obtained from different hospitals in France and Belgium. Paired RNA samples of PTCs and non-tumoral thyroid tissues were obtained from Ukraine via the Chernobyl Tissue Bank (www.chernobyltissuebank.com). Diagnoses were confirmed by the members of the International Pathology Panel of the Chernobyl Tissue Bank.
Project description:Apart from alterations in the RET/PTC-RAS-BRAF pathway, comparatively little is known about the genetics of papillary thyroid carcinoma (PTC). We show that numerous miRNAs are transcriptionally up-regulated in PTC tumors compared with unaffected thyroid tissue. A set of 5 miRNAs including the 3 most upregulated ones (miRs 221, 222, 146) distinguished unequivocally between PTC and normal thyroid. Additionally, miR-221 was upregulated in unaffected thyroid tissue in several PTC patients, presumably an early event in carcinogenesis. Tumors in which the upregulation (11-19 fold) of miRs 221, 222 and 146 was strongest showed dramatic loss of KIT transcript and Kit protein. In five of 10 such cases this was associated with germline single nucleotide changes in the two recognition sequences in KIT for these miRNAs. We conclude that upregulation of several miRs and down regulation of KIT are involved in PTC pathogenesis, and that sequence changes in genes targeted by miRNAs can contribute to their downregulation.