Papers by beatrice Romagnolo
Hepatology Communications, 2021
CTNNB1 (catenin beta 1)-mutated hepatocellular carcinomas (HCCs) account for a large proportion o... more CTNNB1 (catenin beta 1)-mutated hepatocellular carcinomas (HCCs) account for a large proportion of human HCCs. They display high levels of respiratory chain activity. As metabolism and redox balance are closely linked, tumor cells must maintain their redox status during these metabolic alterations. We investigated the redox balance of these HCCs and the feasibility of targeting this balance as an avenue for targeted therapy. We assessed the expression of the nuclear erythroid 2 p45-related factor 2 (NRF2) detoxification pathway in an annotated human HCC data set and reported an enrichment of the NRF2 program in human HCCs with CTNNB1 mutations, largely independent of NFE2L2 (nuclear factor, erythroid 2 like 2) or KEAP1 (Kelch-like ECH-associated protein 1) mutations. We then used mice with hepatocyte-specific oncogenic β-catenin activation to evaluate the redox status associated with β-catenin activation in preneoplastic livers and tumors. We challenged them with various oxidative stressors and observed that the β-catenin pathway activation increased transcription of Nfe2l2, which protects β-catenin-activated hepatocytes from oxidative damage and supports tumor development. Moreover, outside of its effects on reactive oxygen species scavenging, we found out that Nrf2 itself contributes to the metabolic activity of β-catenin-activated cells. We then challenged β-catenin activated tumors pharmacologically to create a redox imbalance and found that pharmacological inactivation of Nrf2 was sufficient to considerably decrease the progression of β-catenin-dependent HCC development. Conclusion: These results demonstrate cooperation between oncogenic β-catenin signaling and the NRF2 pathway in CTNNB1mediated HCC tumorigenesis, and we provide evidence for the relevance of redox balance targeting as a therapeutic strategy in CTNNB1-mutated HCC. (Hepatology Communications 2021;0:1-17). T umorigenesis is a complex process involving multiple modifications promoting proliferation and preventing cell death. The maintenance of neoplastic cell proliferation and growth requires a metabolic rewiring to provide essential macromolecules and energy. (1) Since the first observations that tumor cells displayed higher glucose consumption through a glycolytic pathway, it has been shown that there are numerous metabolic pathways, from enhanced glutaminolysis to increased fatty acid oxidation, that can be altered to favor tumor survival and progression. (2-4) Although altering their metabolic activity, tumor cells also have to maintain a redox status compatible with survival, as metabolism and redox balance are closely linked-mostly through the production
Journal of Hepatology, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Hepatology, 2019
Socioeconomic disadvantage is extremely common among women with depressive symptoms presenting fo... more Socioeconomic disadvantage is extremely common among women with depressive symptoms presenting for women's health care. While social stressors related to socioeconomic disadvantage can contribute to depression, health care tends to focus on patients' symptoms in isolation of context. Health care providers may be more effective by addressing issues related to socioeconomic disadvantage. It is imperative to identify common challenges related to socioeconomic disadvantage, as well as sources of resilience. In this qualitative study, we interviewed 20 women's health patients experiencing depressive symptoms and socioeconomic disadvantage about their views of their mental health, the impact of social stressors, and their resources and skills. A Consensual Qualitative Research approach was used to identify domains consisting of challenges and resiliencies. We applied the socioecological model when coding the data and identified cross-cutting themes of chaos and distress, as well as resilience. These findings suggest the importance of incorporating context in the health care of women with depression and socioeconomic disadvantage.
Médecine sciences : M/S, 2016
Http Www Theses Fr, 1999
L'epithelium intestinal est caracterise par un renouvellement rapide et permanent des cellule... more L'epithelium intestinal est caracterise par un renouvellement rapide et permanent des cellules differenciees qui le composent. Ce processus dynamique est assure par une regulation tres stricte de plusieurs mecanismes cellulaires tels que la proliferation, la differenciation, la migration et l'adherence. Une deregulation des genes affectant l'un ou plusieurs de ces processus cellulaires est a l'origine des developpements tumoraux. L'etude des mecanismes qui assurent l'homeostasie intestinale represente donc un interet fondamental. Dans ce cadre, nous nous interessons d'une part aux mecanismes de regulation transcriptionnelle qui interviennent dans le controle de l'expression des marqueurs de la differenciation intestinale, et d'autre part aux mecanismes responsables des dysfonctionnements de l'epithelium intestinal aboutissant a une transformation tumorale. Pour cela, nous etudions, in vivo, en souris transgeniques, le gene de la Calbindine D9K (CaBP9K) de rat qui est un marqueur de la differenciation enterocytaire dont l'expression est egalement retrouvee au niveau de l'uterus, du poumon et du rein. Nous avons defini les elements d'ADN impliques dans la specificite tissulaire d'expression du gene de la CaBP9K puis caracterise les facteurs de transcription impliques dans l'expression intestinale de ce gene. Nous avons ainsi pu mettre en evidence le role fondamental de Cdx2 dans le controle de l'expression du gene de la CaBP9K au niveau de l'intestin. Cette etude confirme d'autres travaux realises ex vivo sur quelques marqueurs intestinaux dont le gene de la Sucrase Isomaltase. Ainsi Cdx2 apparait etre un des acteurs majeurs de la differenciation intestinale. Ce travail nous a permis de disposer de differents outils moleculaires permettant de generer par oncogenese ciblee des modeles de cancers animaux. Jusqu'a ce jour, aucun modele de carcinogenese intestinale n'a pu etre etabli par une strategie classique d'oncogenese ciblee utilisant des oncogenes et des genes suppresseurs de tumeur. Ceci peut etre du au renouvellement incessant de l'epithelium intestinal. Nous avons teste l'implication de la (β-catenine dans le processus de transformation tumorale de l'epithelium intestinal en surexprimant une forme activee de (β-catenine perturbant la migration et l'adherence cellulaire dans l'epithelium intestinal. Nos resultats indiquent que la surexpression d'une (β- catenine activee est associee a des dysplasies intestinales, suggerant qu'une deregulation de la voie de signalisation Wnt/(3-catenine joue un role majeur dans l'initiation de la cancerogenese intestinale. Cette etude nous a amene a examiner le role d'une deregulation de la signalisation de la voie de Wnt/(β-catenine dans des tumeurs hepatiques. Nous avons ainsi pu demontrer qu'une deregulation de la voie de Wnt/(β-catenine est impliquee dans l'hepatocarcinogenese murine, mais aussi humaine.
Nature Cell Biology, 2015
Here, we show that autophagy is activated in the intestinal epithelium in murine and human colore... more Here, we show that autophagy is activated in the intestinal epithelium in murine and human colorectal cancer and that the conditional inactivation of Atg7 in intestinal epithelial cells inhibits the formation of pre-cancerous lesions in Apc +/− mice by enhancing anti-tumour responses. The antibody-mediated depletion of CD8 + T cells showed that these cells are essential for the anti-tumoral responses mediated by the inhibition of autophagy. We show that Atg7 deficiency leads to intestinal dysbiosis and that the microbiota is required for anticancer responses. In addition, Atg7 deficiency resulted in a stress response accompanied by metabolic defects, AMPK activation and p53-mediated cell-cycle arrest in tumour cells but not in normal tissue. This study reveals that the inhibition of autophagy within the epithelium may prevent the development and progression of colorectal cancer in genetically predisposed patients.
Cancer research, Jan 15, 2001
Inappropriate activation of the Wnt/beta-catenin signaling, resulting mainly from activating muta... more Inappropriate activation of the Wnt/beta-catenin signaling, resulting mainly from activating mutations of the beta-catenin gene, has been implicated recently in the development of hepatocellular carcinoma (HCC). We have generated transgenic mice expressing an oncogenic form of beta-catenin in their hepatocytes to analyze the effect of deregulated beta-catenin signaling on liver homeostasis. These mice rapidly developed hepatomegaly soon after birth, with livers three to four times heavier than those of nontransgenic littermates. The liver cell hyperplasia resulted from increased cell proliferation without any compensatory apoptosis. Although the genes encoding c-myc and cyclin D1 are potential targets of the beta-catenin signaling pathway, neither of them was overexpressed in the hyperplastic livers of beta-catenin transgenic mice. Thus, the key target genes of the beta-catenin signaling pathway in the liver remain to be identified.
Cancer research, Jan 15, 1999
Mutations in the adenomatous polyposis coli gene or activating mutations in the beta-catenin gene... more Mutations in the adenomatous polyposis coli gene or activating mutations in the beta-catenin gene itself are thought to be responsible for the excessive beta-catenin signaling involved in intestinal carcinogenesis. We generated transgenic mice that expressed large amounts of a NH2-terminally truncated mutant beta-catenin (deltaN131beta-catenin) in the intestine. These mice had multifocal dysplastic lesions in the small intestine, reminiscent of the early lesions observed in the mouse models of familial adenomatous polyposis. The number of apoptotic cells in the villi of these transgenic mice was 3-4-fold higher than in nontransgenic mice. Expression of the truncated beta-catenin mutant in the kidney led to the development of severe polycystic kidney disease. Our findings support the concept that deregulation of the beta-catenin signaling pathway is the major oncogenic consequence of adenomatous polyposis coli mutations in intestinal neoplasia.
Journal of Cell Biology, 2012
The stem cells (SCs) at the bottom of intestinal crypts tightly contact niche-supporting cells an... more The stem cells (SCs) at the bottom of intestinal crypts tightly contact niche-supporting cells and fuel the extraordinary tissue renewal of intestinal epithelia. Their fate is regulated stochastically by populational asymmetry, yet whether asymmetrical fate as a mode of SC division is relevant and whether the SC niche contains committed progenitors of the specialized cell types are under debate. We demonstrate spindle alignments and planar cell polarities, which form a novel functional unit that, in SCs, can yield daughter cell anisotropic movement away from niche-supporting cells. We propose that this contributes to SC homeostasis. Importantly, we demonstrate that some SC divisions are asymmetric with respect to cell fate and provide data suggesting that, in some SCs, mNumb displays asymmetric segregation. Some of these processes were altered in apparently normal crypts and microadenomas of mice carrying germline Apc mutations, shedding new light on the first stages of progression ...
Proceedings of the National Academy of Sciences, 2012
Intestinal epithelium has the capacity to self-renew and generate differentiated cells through th... more Intestinal epithelium has the capacity to self-renew and generate differentiated cells through the existence of two types of epithelial stem cells: active crypt base columnar cells (CBCs) and quiescent +4 cells. The behaviors of these cells are regulated both by intrinsic programs and by extrinsic signals sent by neighboring cells, which define the niche. It is clear that the β-catenin pathway acts as an essential intrinsic signal for the maintenance and proliferation of CBC, and it was recently proposed that Paneth cells provide a crucial niche by secreting Wingless/Int (Wnt) ligands. Here, we examined the effect of disrupting the intestinal stem cell niche by inducible deletion of the transcription factor Math1 (Atoh1), an essential driver of secretory cell differentiation. We found that complete loss of Paneth cells attributable to Math1 deficiency did not perturb the crypt architecture and allowed the maintenance and proliferation of CBCs. Indeed, Math1-deficient crypt cells tol...
Proceedings of the National Academy of Sciences, 1998
Hepatocellular carcinoma (HCC) is the major primary malignant tumor in the human liver, but the m... more Hepatocellular carcinoma (HCC) is the major primary malignant tumor in the human liver, but the molecular changes leading to liver cell transformation remain largely unknown. The Wnt-β-catenin pathway is activated in colon cancers and some melanoma cell lines, but has not yet been investigated in HCC. We have examined the status of the β-catenin gene in different transgenic mouse lines of HCC obtained with the oncogenes c- myc or H- ras . Fifty percent of the hepatic tumors in these transgenic mice had activating somatic mutations within the β-catenin gene similar to those found in colon cancers and melanomas. These alterations in the β-catenin gene (point mutations or deletions) lead to a disregulation of the signaling function of β-catenin and thus to carcinogenesis. We then analyzed human HCCs and found similar mutations in eight of 31 (26%) human liver tumors tested and in HepG2 and HuH6 hepatoma cells. The mutations led to the accumulation of β-catenin in the nucleus. Thus alte...
Oncogene, 2001
Autosomal dominant polycystic kidney disease (ADPKD) is common and is a major cause of renal fail... more Autosomal dominant polycystic kidney disease (ADPKD) is common and is a major cause of renal failure. Although the genetics of ADPKD are well known and have led to the discovery of polycystins, a new protein family, the pathogenesis of the disease remains largely unknown. Recent studies have indicated that the b-catenin signaling pathway is one of the targets of the transduction pathway controlled by the polycystins. We have generated transgenic mice that overproduce an oncogenic form of b-catenin in the epithelial cells of the kidney. These mice developed severe polycystic lesions soon after birth that aected the glomeruli, proximal, distal tubules and collecting ducts. The phenotype of these mice mimicked the human ADPKD phenotype. Cyst formation was associated with an increase in cell proliferation and apoptosis. The cell proliferation and apoptotic indexes was increased 4 ± 5-fold and 3 ± 4-fold, respectively, in cystic tubules of the transgenic mice compared to that of littermate controls. Our ®ndings provide experimental genetic evidence that activation of the Wnt/b-catenin signaling pathway causes polycystic kidney disease and support the view that dysregulation of the Wnt/b-catenin signaling is involved in its pathogenesis. Oncogene (2001) 20, 5972 ± 5981.
Laboratory Investigation, 2004
Murine models of familial adenomatous polyposis harbor a germinal heterozygous mutation on Apc tu... more Murine models of familial adenomatous polyposis harbor a germinal heterozygous mutation on Apc tumor suppressor gene. They are valuable tools for studying intestinal carcinogenesis, as most human sporadic cancers contain inactivating mutations of APC. However, Apc þ /À mice, such as the well-characterized Apc Min/ þ model, develop cancers principally in the small intestine, while humans develop mainly colorectal cancers. We used a Cre-loxP strategy to achieve a new model of germline Apc invalidation in which exon 14 is deleted. We compared the phenotype of these Apc D14/ þ mice to that of the classical Apc Min/ þ. The main phenotypic difference is the shift of the tumors in the distal colon and rectum, often associated with a rectal prolapse. Thus, the severity of the colorectal phenotype is partly due to the particular mutation D14, but also to environmental parameters, as mice raised in conventional conditions developed more colon cancers than those raised in pathogen-free conditions. All lesions, including early lesions, revealed Apc LOH and loss of Apc gene expression. They accumulated b-catenin, overexpressed the b-catenin target genes cyclin D1 and c-Myc, and the distribution pattern of glutamine synthetase, a b-catenin target gene recently identified in the liver, was mosaic in intestinal adenomas. The Apc D14/ þ model is thus a useful new tool for studies on the molecular mechanisms of colorectal tumorigenesis.
Journal of Clinical Investigation, 1996
Uterine leiomyomas are a major health problem for women of reproductive age. The molecular biolog... more Uterine leiomyomas are a major health problem for women of reproductive age. The molecular biology of these tumors is poorly understood partly because of the lack of relevant animal models. We have produced transgenic mice expressing the simian virus 40 T antigen driven by the promoter of the Calbindin-D9K (CaBP9K) gene and either Ϫ 1,000 or Ϫ 117 bp of regulatory sequences so as to establish in vivo, uterine smooth muscle tumor models. Six transgenic mouse lines were obtained. Leiomyomas developed in all of them, with an almost complete penetrance of the phenotype. The smooth muscle tumors arose in different parts of the female reproductive tract. Leiomyomas usually developed in the corpus of the uterus, but one mouse line developed leiomyomas in the horn of the uterus, and another in the vagina. The CaBP9K regulatory sequences directing the expression of the Tag gene possess an estradiol responsive element, and accordingly, development of the tumors was strictly under the control of estrogen. Expression of the Tag gene is not only necessary for the initiation of the tumor but also for its development and maintenance. These transgenic mouse models should be useful for studying the pathobiology of uterine leiomyomas and could be instrumental in designing new therapeutic approaches to this disease. (J. Clin. Invest. 1996. 98:777-784.) Key words: estrogens • Calbindin-D9K • uterine smooth muscle • tumor • SV40 T antigen Methods Construction of hybrid genes. Transgenes were constructed by recombinant technology. The construction of the 9K/ Ϫ 1011-Tag and 9K/ Ϫ 117-Tag constructs were prepared as follows. A fragment (from Ϫ 22 to ϩ 365 bp) containing the promoter region (beginning at the SacI site), the first exon, the first intron, and the beginning of the second exon (before the ATG initiation codon) was cloned by PCR. The resulting SacI-EcoRV fragment was then cloned, together with a fragment PstI-SacI containing 5 Ј regulatory sequences of the rat CaBP9K gene
Journal of Biological Chemistry, 1998
The calbindin-D9K gene encodes a vitamin D-induced calcium-binding protein that is expressed as a... more The calbindin-D9K gene encodes a vitamin D-induced calcium-binding protein that is expressed as a marker of small intestine differentiation. We have shown that 4580 base pairs of its 5 DNA regulatory region can target reporter transgene expression in the intestine and cause this transgene to respond like the endogenous gene to vitamin D active metabolite and that the homeoprotein Cdx2 is bound to the TATA box in the intestine. We now show that the 4580 base pairs construct confers a differentiated pattern of reporter transgene expression in the intestine and that cooperation between the proximal promoter and a distal element located in an opened chromatin structure is responsible for the intestinal expression and vitamin D responsiveness of the transgene. Gel shift and footprinting assays using duodenal nuclear extracts indicate that this distal element contains a Cdx2-binding site. Finally, a mutation in this distal Cdx2-binding site dramatically decreases intestinal expression in transgenic mice. This report, using an in vivo approach, demonstrates the crucial role of Cdx2 for the transcription of an intestinal gene. * This work was supported by the Association de Recherche contre le Cancer and the Ligue Nationale contre le Cancer. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. The nucleotide sequence(s) reported in this paper has been submitted to the GenBank TM /EBI Data Bank with accession number(s) X16635.
Gut, 2011
Aims The activation of b-catenin signalling is a key step in intestinal tumorigenesis. Interplay ... more Aims The activation of b-catenin signalling is a key step in intestinal tumorigenesis. Interplay between the b-catenin and Notch pathways during tumorigenesis has been reported, but the mechanisms involved and the role of Notch remain unclear. Methods Notch status was analysed by studying expression of the Notch effector Hes1 and Notch ligands/receptors in human colorectal cancer (CRC) and mouse models of Apc mutation. A genetic approach was used, deleting the Apc and RBP-J or Atoh1 genes in murine intestine. CRC cell lines were used to analyse the control of Hes1 and Atoh1 by b-catenin signalling. Results Notch signalling was found to be activated downstream from b-catenin. It was rapidly induced and maintained throughout tumorigenesis. Hes1 induction was mediated by b-catenin and resulted from both the induction of the Notch ligand/receptor and Notchindependent control of the Hes1 promoter by b-catenin. Surprisingly, the strong phenotype of unrestricted proliferation and impaired differentiation induced by acute Apc deletion in the intestine was not rescued by conditional Notch inactivation. Hyperactivation of b-catenin signalling overrode the forced differention induced by Notch inhibition, through the downregulation of Atoh1, a key secretory determinant factor downstream of Notch. This process involves glycogen synthase kinase 3 b (GSK3b) and proteasome-mediated degradation. The restoration of Atoh1 expression in CRC cell lines displaying b-catenin activation was sufficient to increase goblet cell differentiation, whereas genetic ablation of Atoh1 greatly increased tumour formation in Apc mutant mice. Conclusion Notch signalling is a downstream target of b-catenin hyperactivation in intestinal tumorigenesis. However, its inhibition had no tumour suppressor effect in the context of acute b-catenin activation probably due to the downregulation of Atoh1. This finding calls into question the use of g-secretase inhibitors for the treatment of CRC and suggests that the restoration of Atoh1 expression in CRC should be considered as a therapeutic approach.
The Journal of cell biology, Jan 7, 2011
The unique morphology of tuft cells was first revealed by electron microscopy analyses in several... more The unique morphology of tuft cells was first revealed by electron microscopy analyses in several endoderm-derived epithelia. Here, we explore the relationship of these cells with the other cell types of the intestinal epithelium and describe the first marker signature allowing their unambiguous identification. We demonstrate that although mature tuft cells express DCLK1, a putative marker of quiescent stem cells, they are post-mitotic, short lived, derive from Lgr5-expressing epithelial stem cells, and are found in mouse and human tumors. We show that whereas the ATOH1/MATH1 transcription factor is essential for their differentiation, Neurog3, SOX9, GFI1, and SPDEF are dispensable, which distinguishes these cells from enteroendocrine, Paneth, and goblet cells, and raises from three to four the number of secretory cell types in the intestinal epithelium. Moreover, we show that tuft cells are the main source of endogenous intestinal opioids and are the only epithelial cells that expr...
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Papers by beatrice Romagnolo