hes1-protein--human and Disease-Models--Animal

This review will address contributions of nuclear transcription factors to the embryologic development and definitive function of the anterior pituitary gland. The HESX1, PITX1, PITX2, PROP1 and POU1F1 genes are of particular interest because of their recognized or potential associations with human disease. Mutations of any of the first three genes produce complex disease phenotypes such as septo-optic dysplasia, Treacher Collins Franceschetti syndrome or Rieger syndrome that may include deficiency of one or more pituitary hormones. Mutations in PROP1 or POU1F1, or their mouse homologous, result in severe hypopituitarism as well as morphological abnormalities of the pituitary gland.

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Disease Models, Animal; Genes, Homeobox; Homeobox Protein PITX2; Homeodomain Proteins; Humans; Hypopituitarism; Mice; Mice, Mutant Strains; Nuclear Proteins; Paired Box Transcription Factors; Phenotype; Pituitary Gland; Repressor Proteins; Transcription Factor HES-1; Transcription Factors

This study set out to explore the potential role of microRNA-361-5p (miR-361-5p) in acute pancreatitis through regulation of interleukin-17A (IL-17A). We first identified the expression of miR-361-5p, IL-17A, nuclear factor IA (NFIA), and hes family bHLH transcription factor 1 (Hes1) in serum samples collected from patients with acute pancreatitis, caerulein-induced mice, and a Th17 cell model. The predicted binding of miR-361-5p to NFIA was confirmed

Topics: Animals; Case-Control Studies; Disease Models, Animal; Down-Regulation; Humans; Interleukin-17; Mice; MicroRNAs; NFI Transcription Factors; Nuclear Proteins; Pancreatitis; Th17 Cells; Transcription Factor HES-1

Loss of BRCA1 p220 function often results in basal-like breast cancer (BLBC), but the underlying disease mechanism is largely opaque. In mammary epithelial cells (MECs), BRCA1 interacts with multiple proteins, including NUMB and HES1, to form complexes that participate in interstrand crosslink (ICL) DNA repair and MEC differentiation control. Unrepaired ICL damage results in aberrant transdifferentiation to a mesenchymal state of cultured, human basal-like MECs and to a basal/mesenchymal state in primary mouse luminal MECs. Loss of BRCA1, NUMB, or HES1 or chemically induced ICL damage in primary murine luminal MECs results in persistent DNA damage that triggers luminal to basal/mesenchymal transdifferentiation. In vivo single-cell analysis revealed a time-dependent evolution from normal luminal MECs to luminal progenitor-like tumor cells with basal/mesenchymal transdifferentiation during murine BRCA1 BLBC development. Growing DNA damage accompanied this malignant transformation.

Topics: Animals; BRCA1 Protein; Breast Neoplasms; Cell Differentiation; Cell Transdifferentiation; Cell Transformation, Neoplastic; Disease Models, Animal; DNA Damage; DNA Repair; Epithelial Cells; Female; HEK293 Cells; Humans; Mammary Glands, Animal; MCF-7 Cells; Membrane Proteins; Mice; Mice, Transgenic; Nerve Tissue Proteins; Transcription Factor HES-1; Transfection

Our previous study demonstrated a close relationship between NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). HES1 is a well-known target gene of NOTCH signaling pathway. The purpose of the present study was to further explore the molecular mechanism of HES1 in SACC.. Comparative transcriptome analyses by RNA-Sequencing (RNA-Seq) were employed to reveal NOTCH1 downstream gene in SACC cells. Immunohistochemical staining was used to detect the expression of HES1 in clinical samples. After HES1-siRNA transfected into SACC LM cells, the cell proliferation and cell apoptosis were tested by suitable methods; animal model was established to detect the change of growth ability of tumor. Transwell and wound healing assays were used to evaluate cell metastasis and invasion.. We found that HES1 was strongly linked to NOTCH signaling pathway in SACC cells. The immunohistochemical results implied the high expression of HES1 in cancerous tissues. The growth of SACC LM cells transfected with HES1-siRNAs was significantly suppressed in vitro and tumorigenicity in vivo by inducing cell apoptosis. After HES1 expression was silenced, the SACC LM cell metastasis and invasion ability was suppressed.. The results of this study demonstrate that HES1 is a specific downstream gene of NOTCH1 and that it contributes to SACC proliferation, apoptosis and metastasis. Our findings serve as evidence indicating that HES1 may be useful as a clinical target in the treatment of SACC.

Topics: Adult; Aged; Animals; Apoptosis; Carcinoma, Adenoid Cystic; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Disease Models, Animal; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Middle Aged; Oncogenes; Receptor, Notch1; Recurrence; RNA, Small Interfering; Salivary Gland Neoplasms; Transcription Factor HES-1; Xenograft Model Antitumor Assays

Head and neck squamous cell carcinoma (HNSCC), a common cancer worldwide, is etiologically associated with tobacco use, high alcohol consumption, and high-risk human papillomaviruses (HPV). The Notch signaling pathway, which is involved in cell differentiation decisions with differential downstream targets and effects depending on tissue type and developmental stage, has been implicated in human HNSCC.. To assess the role of Notch signaling in HPV-positive and HPV-negative HNSCC, we utilized genetically engineered mouse (GEM) models for conventional keratinizing HNSCC, in which either HPV16 E6 and E7 oncoproteins or a gain-of-function mutant p53 are expressed, and in which we inactivated canonical Notch signaling via expression of a dominant negative form of MAML1 (DNMAML1), a required transcriptional coactivator of Notch signaling.. Loss of canonical Notch signaling increased tumorigenesis in both contexts and also caused an increase in nuclear β-catenin, a marker for increased tumorigenic potential. When combined with loss of canonical Notch signaling, HPV oncogenes led to the highest frequency of cancers overall and the largest number of poorly differentiated (high-grade) cancers.. These findings inform on the contribution of loss of canonical Notch signaling in head and neck carcinogenesis.

Topics: Animals; Cell Transformation, Neoplastic; Cell Transformation, Viral; Disease Models, Animal; DNA-Binding Proteins; Female; Gene Expression; Head and Neck Neoplasms; Human papillomavirus 16; Humans; Male; Mice; Mice, Transgenic; Molecular Targeted Therapy; Oncogene Proteins, Viral; Papillomavirus E7 Proteins; Papillomavirus Infections; Receptors, Notch; Repressor Proteins; Severity of Illness Index; Signal Transduction; Transcription Factor HES-1; Transcription Factors

To analyze the expression and function of the Notch signaling target gene Hes1 in a rhesus rotavirus-induced mouse biliary atresia model.. The morphologies of biliary epithelial cells in biliary atresia patients and in a mouse model were examined by immunohistochemical staining. Then, the differential expression of Notch signaling pathway-related molecules was investigated. Further, the effects of the siRNA-mediated inhibition of Hes1 expression were examined using a biliary epithelial cell 3D culture system.. Both immature (EpCAM. Our data indicated that Hes1 might contribute to the maturation and the cellular structure organization of biliary epithelial cells, which provides new insight into understanding the pathology of biliary atresia.

Topics: Animals; Bile Ducts; Biliary Atresia; Cell Culture Techniques; Cells, Cultured; Choledochal Cyst; Disease Models, Animal; Down-Regulation; Epithelial Cells; Female; Gene Expression Profiling; Humans; Immunoglobulin J Recombination Signal Sequence-Binding Protein; Liver; Mice; Mice, Inbred BALB C; Microscopy, Electron; Receptors, Notch; RNA Interference; RNA, Small Interfering; Rotavirus; Signal Transduction; Transcription Factor HES-1

Perturbation of keratinocyte differentiation by E6/E7 oncoproteins of high-risk human papillomaviruses that drive oncogenic transformation of cells in squamocolumnar junction of the uterine cervix may confer "stem-cell like" characteristics. However, the crosstalk between E6/E7 and stem cell signaling during cervical carcinogenesis is not well understood. We therefore examined the role of viral oncoproteins in stem cell signaling and maintenance of stemness in cervical cancer.. Isolation and enrichment of cervical cancer stem-like cells (CaCxSLCs) was done from cervical primary tumors and cancer cell lines by novel sequential gating using a set of functional and phenotypic markers (ABCG2, CD49f, CD71, CD133) in defined conditioned media for assessing sphere formation and expression of self-renewal and stemness markers by FACS, confocal microscopy, and qRT-PCR. Differential expression level and DNA-binding activity of Notch1 and its downstream targets in CaCxSLCs as well as silencing of HPVE6/Hes1 by siRNA was evaluated by gel retardation assay, FACS, immunoblotting, and qRT-PCR followed by in silico and in vivo xenograft analysis.. CaCxSLCs showed spheroid-forming ability, expressed self-renewal and stemness markers Oct4, Sox2, Nanog, Lrig1, and CD133, and selectively overexpressed E6 and HES1 transcripts in both cervical primary tumors and cancer cell lines. The enriched CaCxSLCs were highly tumorigenic and did recapitulate primary tumor histology in nude mice. siRNA silencing of HPVE6 or Hes1 abolished sphere formation, downregulated AP-1-STAT3 signaling, and induced redifferentiation.. Our findings suggest the possible mechanism by which HPVE6 potentially regulate and maintain stem-like cancer cells through Hes1. Clin Cancer Res; 22(16); 4170-84. ©2016 AACR.

Topics: Animals; ATP-Binding Cassette Transporters; Biomarkers; Cell Line, Tumor; Cell Self Renewal; Cell Transformation, Neoplastic; Cell Transformation, Viral; Disease Models, Animal; Female; Gene Expression Regulation, Neoplastic; Genes, fos; Genes, jun; HeLa Cells; Humans; Mice; Mice, Inbred NOD; Models, Biological; Neoplastic Stem Cells; Oncogene Proteins, Viral; Protein Interaction Maps; Receptor, Notch1; RNA Interference; Signal Transduction; STAT3 Transcription Factor; Transcription Factor HES-1; Uterine Cervical Neoplasms

Perturbation of pancreatic acinar cell state can lead to acinar-to-ductal metaplasia (ADM), a precursor lesion to the development of pancreatic ductal adenocarcinoma (PDAC). In the pancreas, Notch signaling is active both during development and in adult cellular differentiation processes. Hes1, a key downstream target of the Notch signaling pathway, is expressed in the centroacinar compartment of the adult pancreas as well as in both preneoplastic and malignant lesions. In this study, we used a murine genetic in vivo approach to ablate Hes1 in pancreatic progenitor cells (Ptf1a

Topics: Acinar Cells; Animals; Carcinogenesis; Carcinoma, Pancreatic Ductal; Cell Differentiation; Cell Plasticity; Ceruletide; Disease Models, Animal; Female; Humans; Male; Metaplasia; Mice; Pancreas; Pancreas, Exocrine; Pancreatic Neoplasms; Pancreatitis; Regeneration; Signal Transduction; Stem Cells; Transcription Factor HES-1

Little is known about the roles of Notch signaling in cholangiocarcinoma (CC). The expression of hairy and enhancer of split 1 (Hes-1) has not been investigated yet in resected specimens of CC. Notch signaling has been reported to be related to cancer stem cell (CSC) like properties in some malignancies. Our aim is to investigate the participation of Notch signaling in resected specimens of extrahepatic CC (EHCC) and to evaluate the efficacy of CC cells with CSC-like properties by Notch signaling blockade.. First, the expression of Notch1, 2, 3, 4 and Hes-1 was examined by immunohistochemistry in 132 resected EHCC specimens. The clinicopathological characteristics in the expression of Notch receptors and Hes-1 were investigated. Second, GSI IX, which is a γ-secretase-inhibitor, was used for Notch signaling blockade in the following experiment. Alterations of the subpopulation of CD24. Notch1, 2, 3, 4 and Hes-1 in the resected EHCC specimens were expressed in 50.0, 56.1, 42.4, 6.1, and 81.8 % of the total cohort, respectively. Notch1 and 3 expressions were associated with poorer histological differentiation (P = 0.008 and 0.053). The patients with the expression of at least any one of Notch1-3 receptors, who were in 80.3 % of the total, exhibited poorer survival (P = 0.050). Similarly, the expression of Hes-1 tended to show poor survival (P = 0.093). In all of the examined CC cell lines, GSI IX treatment significantly diminished the subpopulation of CD24. Aberrant Notch signaling is involved with EHCC. Inhibition of Notch signaling is a novel therapeutic strategy for targeting cells with CSC-like properties.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Bile Duct Neoplasms; Biomarkers; Cell Line, Tumor; Cell Proliferation; Cholangiocarcinoma; Disease Models, Animal; Female; Gene Expression; Heterografts; Humans; Immunohistochemistry; Immunophenotyping; Male; Middle Aged; Neoplasm Grading; Neoplasm Metastasis; Neoplasm Staging; Neoplastic Stem Cells; Receptors, Notch; Signal Transduction; Transcription Factor HES-1; Young Adult

Cellular therapy has provided hope for restoring neurological function post stroke through promoting endogenous neurogenesis, angiogenesis and synaptogenesis. The current study was based on the observation that transplantation of human umbilical cord mesenchymal stem cells (hUCMSCs) promoted the neurological function improvement in stroked mice and meanwhile enhanced angiogenesis in the stroked hemisphere. Grafted hUCMSCs secreted human vascular endothelial growth factor A (VEGF-A). Notch1 signaling was activated after stroke and also in the grafted hUCMSCs. To address the potential mechanism that might mediate such pro-angiogenic effect, we established a hUCMSC-neuron co-culture system. Neurons were subjected to oxygen glucose deprivation (OGD) injury before co-culturing to mimic the in vivo cell transplantation. Consistent with the in vivo data, co-culture medium claimed from hUCMSC-OGD neuron co-culture system significantly promoted the capillary-like tube formation of brain-derived endothelial cells. Moreover, coincident with our in vivo data, Notch 1 signaling activation was detected in hUCMSCs after co-cultured with OGD neurons as demonstrated by the up-regulation of key Notch1 signaling components Notch1 and Notch1 intercellular domain (NICD). In addition, OGD-neuron co-culture also increased the VEGF-A production by hUCMSCs. To verify whether Notch1 activation was involved in the pro-angiogenic effect, γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) was added into the co-culture medium before co-culture. It turned out that DAPT significantly prevented the Notch1 activation in hUCMSCs after co-culture with OGD neurons. More importantly, the pro-angiogenic effect of hUCMSCs was remarkably abolished by DAPT addition as demonstrated by inhibited capillary-like tube formation and less VEGF-A production. Regarding how Notch1 signaling was linked with VEGF-A secretion, we provided some clue that Notch1 effector Hes1 mRNA expression was significantly up-regulated by OGD-neuron co-culturing and down-regulated after additional treatment of DAPT. In summary, our data provided evidence that the VEGF-A secretion from hUCMSCs after being triggered by OGD neurons is Notch1 signaling associated. This might be a possible mechanism that contributes to the angiogenic effect of hUCMSC transplantation in stroked brain.

Topics: Amyloid Precursor Protein Secretases; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Hypoxia; Coculture Techniques; Cord Blood Stem Cell Transplantation; Disease Models, Animal; Fetal Blood; Glucose; Homeodomain Proteins; Humans; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice, Inbred C57BL; Neovascularization, Physiologic; Neurons; Random Allocation; Receptor, Notch1; RNA, Messenger; Signal Transduction; Stroke; Transcription Factor HES-1; Vascular Endothelial Growth Factor A

New Findings What is the central question of this study? The Notch signalling pathway plays an important role in muscle regeneration, and activation of the pathway has been shown to enhance muscle regeneration in aged mice. It is unknown whether Notch activation will have a similarly beneficial effect on muscle regeneration in the context of Duchenne muscular dystrophy (DMD). What is the main finding and its importance? Although expression of Notch signalling components is altered in both mouse models of DMD and in human DMD patients, activation of the Notch signalling pathway does not confer any functional benefit on muscles from dystrophic mice, suggesting that other signalling pathways may be more fruitful targets for manipulation in treating DMD. Abstract In Duchenne muscular dystrophy (DMD), muscle damage and impaired regeneration lead to progressive muscle wasting, weakness and premature death. The Notch signalling pathway represents a central regulator of gene expression and is critical for cellular proliferation, differentiation and apoptotic signalling during all stages of embryonic muscle development. Notch activation improves muscle regeneration in aged mice, but its potential to restore regeneration and function in muscular dystrophy is unknown. We performed a comprehensive examination of several genes involved in Notch signalling in muscles from dystrophin-deficient mdx and dko (utrophin- and dystrophin-null) mice and DMD patients. A reduction of Notch1 and Hes1 mRNA in tibialis anterior muscles of dko mice and quadriceps muscles of DMD patients and a reduction of Hes1 mRNA in the diaphragm of the mdx mice were observed, with other targets being inconsistent across species. Activation and inhibition of Notch signalling, followed by measures of muscle regeneration and function, were performed in the mouse models of DMD. Notch activation had no effect on functional regeneration in C57BL/10, mdx or dko mice. Notch inhibition significantly depressed the frequency-force relationship in regenerating muscles of C57BL/10 and mdx mice after injury, indicating reduced force at each stimulation frequency, but enhanced the frequency-force relationship in muscles from dko mice. We conclude that while Notch inhibition produces slight functional defects in dystrophic muscle, Notch activation does not significantly improve muscle regeneration in murine models of muscular dystrophy. Furthermore, the inconsistent expression of Notch targets between murine mode

Topics: Adolescent; Adult; Animals; Basic Helix-Loop-Helix Transcription Factors; Biopsy; Case-Control Studies; Child; Child, Preschool; Disease Models, Animal; Dystrophin; Elapid Venoms; Homeodomain Proteins; Humans; Infant; Mice, Inbred mdx; Mice, Knockout; Muscle Contraction; Muscle Development; Muscle Strength; Muscle, Skeletal; Muscular Diseases; Muscular Dystrophy, Duchenne; Receptor, Notch1; Receptors, Notch; Regeneration; RNA, Messenger; Signal Transduction; Transcription Factor HES-1; Utrophin; Young Adult

Pancreatic cancer stem cells (CSCs) represent a small subpopulation of pancreatic cancer cells that have the capacity to initiate and propagate tumor formation. However, the mechanisms by which pancreatic CSCs are maintained are not well understood or characterized.. Expression of Notch receptors, ligands, and Notch signaling target genes was quantitated in the CSC and non-CSC populations from 8 primary human pancreatic xenografts. A gamma secretase inhibitor (GSI) that inhibits the Notch pathway and a shRNA targeting the Notch target gene Hes1 were used to assess the role of the Notch pathway in CSC population maintenance and pancreatic tumor growth.. Notch pathway components were found to be upregulated in pancreatic CSCs. Inhibition of the Notch pathway using either a gamma secretase inhibitor or Hes1 shRNA in pancreatic cancer cells reduced the percentage of CSCs and tumorsphere formation. Conversely, activation of the Notch pathway with an exogenous Notch peptide ligand increased the percentage of CSCs as well as tumorsphere formation. In vivo treatment of orthotopic pancreatic tumors in NOD/SCID mice with GSI blocked tumor growth and reduced the CSC population.. The Notch signaling pathway is important in maintaining the pancreatic CSC population and is a potential therapeutic target in pancreatic cancer.

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; Ligands; Mice, Inbred NOD; Mice, SCID; Neoplastic Stem Cells; Pancreatic Neoplasms; Protease Inhibitors; Receptors, Notch; RNA, Small Interfering; Signal Transduction; Spheroids, Cellular; Transcription Factor HES-1; Tumor Cells, Cultured; Up-Regulation

Obesity is often attributed to a Western lifestyle, a high-fat diet and decreased activity. While these factors certainly contribute to adult obesity, compelling data from our laboratory and others indicate that this explanation is oversimplified. Recent studies strongly argue that maternal/fetal under- or overnutrition predisposes the offspring to become hyperphagic and increases the risk of later obesity. Both infants small for gestational age (SGA) or infants born to obese mothers who consume a high-fat diet are at a markedly increased risk of adult obesity. Specific alterations in the fetal metabolic/energy environment directly influence the development of appetite regulatory pathways. Specifically, SGA infants demonstrate (1) impaired satiety and anorexigenic cell signaling, (2) enhanced cellular orexigenic responses, (3) programmed dysfunction of neuroprogenitor cell proliferation/differentiation, and (4) increased expression of appetite (NPY) versus satiety (POMC) neurons. In both hypothalamic tissue and ex vivo culture, SGA newborns exhibit increased levels of the nutrient sensor SIRT1, signifying reduced energy, whereas maternal high-fat-exposed newborns exhibit reduced levels of pAMPK, signifying energy excess. Via downstream regulation of bHLH neuroproliferation (Hes1) and neurodifferentiation factors (Mash1, Ngn3), neurogenesis is biased toward orexigenic and away from anorexigenic neurons, resulting in excess appetite, reduced satiety and development of obesity. Despite the developmental programming of appetite neurogenesis, the potential for neuronal remodeling raises the opportunity for novel interventions.

Topics: Animals; Appetite; Basic Helix-Loop-Helix Transcription Factors; Cell Proliferation; Diet, High-Fat; Disease Models, Animal; Female; Fetal Development; Gene Expression Regulation; Homeodomain Proteins; Humans; Hyperphagia; Hypothalamus; Infant; Infant, Newborn; Infant, Small for Gestational Age; Maternal Nutritional Physiological Phenomena; Nerve Tissue Proteins; Neurogenesis; Obesity; Overnutrition; Satiation; Sirtuin 1; Transcription Factor HES-1

Chemotherapeutic treatment of hepatocellular carcinoma often leads to chemoresistance during therapy or upon relapse of tumors. For the development of better treatments a better understanding of biochemical changes in the resistant tumors is needed. In this study, we focus on the characterization of in vivo chemoresistant human hepatocellular carcinoma HUH-REISO established from a metronomically cyclophosphamide (CPA) treated HUH7 xenograft model.. SCID mice bearing subcutaneous HUH7 tumors were treated i.p. with 75 mg/kg CPA every six days. Tumors were evaluated by immunohistochemistry, a functional blood-flow Hoechst dye assay, and qRT-PCR for ALDH-1, Notch-1, Notch-3, HES-1, Thy-1, Oct-4, Sox-2 and Nanog mRNA levels. Cell lines of these tumors were analyzed by qRT-PCR and in endothelial transdifferentiation studies on matrigel.. HUH-REISO cells, although slightly more sensitive against activated CPA in vitro than parental HUH-7 cells, fully retained their in vivo CPA chemoresistance upon xenografting into SCID mice. Histochemical analysis of HUH-REISO tumors in comparison to parental HUH-7 cells and passaged HUH-PAS cells (in vivo passaged without chemotherapeutic pressure) revealed significant changes in host vascularization of tumors and especially in expression of the tumor-derived human endothelial marker gene PECAM-1/CD31 in HUH-REISO. In transdifferentiation studies with limited oxygen and metabolite diffusion, followed by a matrigel assay, only the chemoresistant HUH-REISO cells exhibited tube formation potential and expression of human endothelial markers ICAM-2 and PECAM-1/CD31. A comparative study on stemness and plasticity markers revealed upregulation of Thy-1, Oct-4, Sox-2 and Nanog in resistant xenografts. Under therapeutic pressure by CPA, tumors of HUH-PAS and HUH-REISO displayed regulations in Notch-1 and Notch-3 expression.. Chemoresistance of HUH-REISO was not manifested under standard in vitro but under in vivo conditions. HUH-REISO cells showed increased pluripotent capacities and the ability of transdifferentiation to endothelial like cells in vitro and in vivo. These cells expressed typical endothelial surface marker and functionality. Although the mechanism behind chemoresistance of HUH-REISO and involvement of plasticity remains to be clarified, we hypothesize that the observed Notch regulations and upregulation of stemness genes in resistant xenografts are involved in the observed cell plasticity.

Topics: Administration, Metronomic; Aldehyde Dehydrogenase 1 Family; Animals; Antineoplastic Agents; Basic Helix-Loop-Helix Transcription Factors; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Transdifferentiation; Disease Models, Animal; Drug Resistance, Neoplasm; Endothelial Cells; Female; Gene Expression Profiling; Homeodomain Proteins; Humans; Isoenzymes; Liver Neoplasms; Male; Mice; Nanog Homeobox Protein; Neovascularization, Pathologic; Octamer Transcription Factor-3; Receptor, Notch1; Retinal Dehydrogenase; SOXB1 Transcription Factors; Spheroids, Cellular; Thy-1 Antigens; Transcription Factor HES-1; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Adenomatous polyps are precursors to colorectal cancer (CRC), whereas hyperplastic polyps (HPPs) have low risk of progression to CRC. Mutations in KRAS are found in ∼40% of CRCs and large adenomas and a subset of HPPs. We investigated the reasons why HPPs with KRAS mutations lack malignant potential and compared the effects of Kras/KRAS activation with those of Apc/APC inactivation, which promotes adenoma formation.. We activated a KrasG12D mutant allele or inactivated Apc alleles in mouse colon epithelium and analyzed phenotypes and expression of selected genes and proteins. The mouse data were validated using samples of human HPPs and adenomas. Signaling pathways and factors contributing to Kras/KRAS-induced phenotypes were studied in intestinal epithelial cells.. Activation of Kras led to hyperplasia and serrated crypt architecture akin to that observed in human HPPs. We also observed loss of Paneth cells and increases in goblet cell numbers. Abnormalities in Kras-mediated differentiation and proliferation required mitogen-activated protein kinase signaling and were linked to activation of the Hes1 transcription factor. Human HPPs also had activation of HES1. In contrast to Apc/APC inactivation, Kras/KRAS activation did not increase expression of crypt stem cell markers in colon epithelium or colony formation in vitro. Kras/KRAS activation was not associated with substantial induction of p16(INK4a) protein expression in mouse colon epithelium or human HPPs.. Although Kras/KRAS mutation promotes serrated and hyperplastic morphologic features in colon epithelium, it is not able to initiate adenoma development, perhaps in part because activated Kras/KRAS signaling does not increase the number of presumptive stem cells in affected crypts.

Topics: Adenoma; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Differentiation; Cell Line; Cell Proliferation; Colon; Colonic Polyps; Colorectal Neoplasms; Disease Models, Animal; Disease Progression; Homeodomain Proteins; Humans; Hyperplasia; Intestinal Mucosa; Mice; Mice, Transgenic; Mutation; Proto-Oncogene Proteins p21(ras); Signal Transduction; Stem Cells; Transcription Factor HES-1

Notch signaling regulates cell differentiation and proliferation, contributing to the maintenance of diverse tissues including the intestinal epithelia. However, its role in tissue regeneration is less understood. Here, we show that Notch signaling is activated in a greater number of intestinal epithelial cells in the inflamed mucosa of colitis. Inhibition of Notch activation in vivo using a gamma-secretase inhibitor resulted in a severe exacerbation of the colitis attributable to the loss of the regenerative response within the epithelial layer. Activation of Notch supported epithelial regeneration by suppressing goblet cell differentiation, but it also promoted cell proliferation, as shown in in vivo and in vitro studies. By utilizing tetracycline-dependent gene expression and microarray analysis, we identified a novel group of genes that are regulated downstream of Notch1 within intestinal epithelial cells, including PLA2G2A, an antimicrobial peptide secreted by Paneth cells. Finally, we show that these functions of activated Notch1 are present in the mucosa of ulcerative colitis, mediating cell proliferation, goblet cell depletion, and ectopic expression of PLA2G2A, thereby contributing to the regeneration of the damaged epithelia. This study showed the critical involvement of Notch signaling during intestinal tissue regeneration, regulating differentiation, proliferation, and antimicrobial response of the epithelial cells. Thus Notch signaling is a key intracellular molecular pathway for the proper reconstruction of the intestinal epithelia.

Topics: Alanine; Amyloid Precursor Protein Secretases; Animals; Azepines; Basic Helix-Loop-Helix Transcription Factors; Cell Differentiation; Cell Proliferation; Colitis; Colon; Dextran Sulfate; Disease Models, Animal; Enzyme Inhibitors; Goblet Cells; Group II Phospholipases A2; Homeodomain Proteins; HT29 Cells; Humans; Mice; Mice, Inbred C57BL; Paneth Cells; Receptor, Notch1; Receptors, Notch; Regeneration; Signal Transduction; Transcription Factor HES-1

Brain arteriovenous malformations (BAVMs) can cause lethal hemorrhagic stroke and have no effective treatment. The cellular and molecular basis for this disease is largely unknown. We have previously shown that expression of constitutively-active Notch4 receptor in the endothelium elicits and maintains the hallmarks of BAVM in mice, thus establishing a mouse model of the disease. Our work suggested that Notch pathway could be a critical molecular mediator of BAVM pathogenesis. Here, we investigated the hypothesis that upregulated Notch activation contributes to the pathogenesis of human BAVM. We examined the expression of the canonical Notch downstream target Hes1 in the endothelium of human BAVMs by immunofluorescence, and showed increased levels relative to either autopsy or surgical biopsy controls. We then analyzed receptor activity using an antibody to the activated form of the Notch1 receptor, and found increased levels of activity. These findings suggest that Notch activation may promote the development and even maintenance of BAVM. We also detected increases in Hes1 and activated Notch1 expression in our mouse model of BAVM induced by constitutively active Notch4, demonstrating molecular similarity between the mouse model and the human disease. Our work suggests that activation of Notch signaling is an important molecular candidate in BAVM pathogenesis and further validates that our animal model provides a platform to study the progression as well as the regression of the disease.

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Disease Models, Animal; Endothelium, Vascular; Homeodomain Proteins; Humans; Intracranial Arteriovenous Malformations; Mice; Mice, Mutant Strains; Microscopy, Fluorescence; Neovascularization, Pathologic; Proto-Oncogene Proteins; Receptor, Notch1; Receptor, Notch4; Receptors, Notch; Signal Transduction; Transcription Factor HES-1; Up-Regulation