Project description:The molecular events implicated in the development of endometrial carcinosarcoma remain poorly understood. Using complementary DNA microarrays, we analyzed a group of 15 endometrial carcinosarcomas and compared their gene expression profiles with those obtained from a group of 23 endometrioid endometrial carcinomas. We demonstrated changes in the expression of genes modulating processes such as the epithelial to mesenchymal transition, muscle differentiation, the expression of cancer/testis antigens, and immune response in endometrial carcinosarcomas. The high mobility group AT-hook 2 gene is an embryonic nuclear factor that mediates epithelial to mesenchymal transition in various tumor models, and it was among the genes overexpressed in endometrial carcinosarcomas. High mobility group AT-hook 2 overexpression was confirmed in 54% of endometrial carcinosarcomas by quantitative real time-polymerase chain reaction and immunohistochemistry. Moreover, we found a significant inverse correlation between the expression of high mobility group AT-hook 2 and let-7b, a member of the let-7 family of microRNAs that represses high mobility group AT-hook 2 expression. These changes were also associated with overexpression of Lin28B, a suppressor of microRNA biogenesis that is implicated in cancer progression and metastasis. Finally, high mobility group AT-hook 2 overexpression, which was detected in less than 3% of endometrioid endometrial carcinomas, was observed in many nonendometrioid carcinomas (46% of 28 samples). This pattern of expression, restricted to nonendometrioid carcinomas and endometrial carcinosarcomas, reflects a role for high mobility group AT-hook 2 in endometrial carcinogenesis that is associated with aggressive phenotypes and points to its potential use as a marker to distinguish between endometrioid and nonendometrioid tumors.
Project description:The molecular events that mediate the epithelial to mesenchymal transition (EMT) in endometrial cancer remain poorly understood. Using cDNA microarrays, we analyzed a group of endometrial carcinosarcomas (ECS), a true example of EMT in vivo, and we compared their gene expression profiles with those obtained from a group of endometrioid endometrial carcinomas (EEC). The HMGA2 gene (High Mobility Group AT-hook 2), an embryonic nuclear factor that mediates EMT in various tumour models, was among the genes overexpressed in ECS, and HMGA2 overexpression was confirmed in 54% of ECSs by qRT-PCR and immunohistochemistry. Moreover, we found a significant inverse correlation between the expression of HMGA2 and let-7b, a member of the let-7 family of miRNAs that represses HMGA2 expression. These changes were also associated with overexpression of Lin28B, a suppressor of microRNA biogenesis implicated in cancer progression and metastasis. Finally, HMGA2 overexpression, which was detected in less than 3% of EECs, was observed in many non-endometrioid carcinomas (46%). For the first time, we describe a role for HMGA2 in both the process of EMT that contributes to endometrial carcinogenesis and in the acquisition of aggressive phenotypes by this neoplasia. Moreover, we demonstrate changes in the expression of genes modulating processes such as EMT, muscle differentiation, the expression of cancer testis antigens (CTAs) and the immune response. Identification of new molecular markers in endometrial carcinogenesis 15 endometrial carcinosarcomas and 23 endometrioid endometrial carcinoma
Project description:We sought to identify critical factors regulating muscle stem cell activation and commitment, and determined through loss-of-function analyses that HMGA2 (high mobility group AT-hook 2) is a key regulator of myogenesis both in vitro and in vivo.
Project description:We sought to identify critical factors regulating muscle stem cell activation and commitment, and determined through loss-of-function analyses that HMGA2 (high mobility group AT-hook 2) is a key regulator of myogenesis both in vitro and in vivo. mRNAs were isolated from Hmga2 -/- and Hmga2 +/+ mice myoblasts, and a microarray experiment was performed.
Project description:The high-mobility-group (HMG) proteins are the most abundant non-histone chromatin-associated proteins. Here we deciphered the role of the high mobility group AT-hook protein 2 (HMGA2) during lung development by analyzing the lung of Hmga2 deficient mice (Hmga2-/-).We found that Hmga2 is expressed in the mouse embryonic lung at the distal airways. Analysis of Hmga2-/- mice showed that Hmga2 is required for proper cell proliferation and distal epithelium differentiation during embryonic lung development. Hmga2 knockout (KO) led to enhanced canonical WNT signaling due to an increased expression of secreted WNT glycoproteins Wnt2b, Wnt7b and Wnt11 as well as a reduction of the WNT signaling antagonizing proteins GATA6 (GATA binding protein 6) and FZD2 (frizzled homolog 2). Comparison of Hmga2-/- with Hmga2+/+ mice by Affymetrix microarray-based expression analysis of embryonic lung revealed an increased expression of genes whose products participate in cell cycle and canonical Wnt signaling. Affymetrix microarray transcriptome analysis of Hmga2-/- and Hmga2+/+ embryonic lung (E18.5) was performed and analyzed
Project description:The transcription regulator High Mobility Group AT-Hook 2 (HMGA2) plays an important role in many types of cancers, but the molecular mechanisms are not fully elucidated. We found by knock-down studies that HMGA2 controls expression of ATF4 and the enzymes in the serine synthesis pathway in triple negative breast cancer cells, and that HMGA2 expression correlates with poor clinical outcome in ER negative breast cancers. Furthermore, we found that the metabolism was dysregulated in cells with reduced HMGA2 expression, which affected their response to mitochondrial stressors and to changed carbon sources. Altogether, our findings demonstrate that HMGA2 is a regulator of serine biosynthesis and metabolism, consistent with the well-known role of HMGA2 as a regulator of proliferation, epithelial-mesenchymal transition and stemness.
Project description:The high-mobility-group (HMG) proteins are the most abundant non-histone chromatin-associated proteins. Here we deciphered the role of the high mobility group AT-hook protein 2 (HMGA2) during lung development by analyzing the lung of Hmga2 deficient mice (Hmga2-/-).We found that Hmga2 is expressed in the mouse embryonic lung at the distal airways. Analysis of Hmga2-/- mice showed that Hmga2 is required for proper cell proliferation and distal epithelium differentiation during embryonic lung development. Hmga2 knockout (KO) led to enhanced canonical WNT signaling due to an increased expression of secreted WNT glycoproteins Wnt2b, Wnt7b and Wnt11 as well as a reduction of the WNT signaling antagonizing proteins GATA6 (GATA binding protein 6) and FZD2 (frizzled homolog 2). Comparison of Hmga2-/- with Hmga2+/+ mice by Affymetrix microarray-based expression analysis of embryonic lung revealed an increased expression of genes whose products participate in cell cycle and canonical Wnt signaling.
Project description:The eukaryotic genome is organized into chromatin, which constitutes the physiological template for DNA-dependent processes including replication, recombination, repair and transcription. Chromatin mediated transcription regulation involves histone modifications, chromatin remodeling and DNA methylation. However, the precise biological function of non-histone chromatin-associated proteins is still unclear. The high mobility group proteins are the most abundant non-histone chromatin-associated proteins. Here we combined proteomic, ChIP-seq and transcriptome data to decipher the mechanism of transcriptional regulation mediated by the high mobility group AT-hook protein 2 (HMGA2). We showed that HMGA2-induced transcription requires H2AX phosphorylation at S139 (H2AXS139ph; γ-H2AX), mediated by the kinase ataxia telangiectasia mutated (ATM). Furthermore, we demonstrated the relevance of this mechanism within the biological context of TGFB1-signaling. Our results link H2AXS139ph, a marker for DNA damage, to transcription, which is a new function for this histone modification. The interplay between HMGA2, ATM and H2AX is a novel mechanism of transcription initiation. Chip-seq data of HMGA2, H2AXS139ph and ATM obtained from Mouse embryonic Fibroblast cells in wt and Ko of Hmga2
Project description:Differentiation of 3T3-L1 cells into adipocytes involves a highly orchestrated series of events including clonal expansion, growth arrest and terminal differentiation. The mechanisms coordinating these different steps are not yet fully understood. Here we investigated whether micro (mi)RNAs play a role in this process. Microarray analysis was performed to detect miRNA expression during 3T3-L1 preadipocyte differentiation. Several miRNAs, including let-7, were up-regulated during 3T3-L1 adipogenesis. Ectopic introduction of let-7 into 3T3-L1 cells inhibited clonal expansion as well as terminal differentiation. The mRNA encoding high mobility group AT-hook 2 (HMGA2), a transcription factor that regulates growth and proliferation in other contexts, was inversely correlated with let-7 levels during 3T3-L1 cell adipogenesis, and let-7 markedly reduced HMGA2 concentrations. Knockdown of HMGA2 inhibited 3T3-L1 differentiation. These results suggest that let-7 plays an important role in adipocyte differentiation and that it does so in part by targeting HMGA2, thereby regulating the transition from clonal expansion to terminal differentiation. 3T3-L1 cells were induced to differentiation into mature adipocytes using a canonical DMI cocktail. The time point at two days after confluency of 3T3-L1 was defined as day 0. Samples were collected at day 0, day 1, day 4, and day 7. The expression of microRNAs at day 1, day 4, and day 7 was compared to that of day 0.