Upregulation Of Hes1 Research Articles

304 NF2 Loss-of-Function and Hypoxia Together Drive Radioresistance in Grade 2 Meningiomas

INTRODUCTION: Grade 2 meningiomas (G2Ms) are associated with an aggressive natural history characterized by recurrence and resistance to radiation therapy. Histopathological necrosis is associated with worse progression-free survival (PFS) following radiation therapy in G2Ms. We seek to understand the molecular pathophysiology of radiation resistance and to identify molecular biomarkers and therapeutic targets for radioresistant G2M. METHODS: We performed genetic sequencing and histopathological analysis of 121 G2Ms. Using the IOMM-Lee meningioma cell line, we investigated the role of tumor hypoxia and genes of interest in radio-resistance through lentivirally targeted gene knockdown and clonogenic survival assays following exposure to ionizing radiation. Transcriptional profiling of cells in in vitro and in 38 patient G2Ms was performed using RNA sequencing. RESULTS: NF2 loss of function mutations were significantly associated with tumor necrosis in G2Ms (p = 0.0026). Patients with NF2mutation and spontaneous necrosis had worse post-radiation PFS compared to NF2 wildtype patients without necrosis (p = 0.035). In the setting of hypoxia, NF2 knockdown significantly increased radio-resistance in vitro (p < 0.001). Gene set enrichment analysis on in vivo and in vitro data and functional assays revealed downregulation of apoptosis and upregulation of cell proliferation in NF2-deficient and necrotic group compared to control. Integration of differentially expressed genes in both NF2-deficient cells in vitro and human necrotic tumors identified shared upregulation of HES1, XDH, NOG, IGFBP3, ALOXE3, THSB1, and TRIML2, suggesting these genes may represent targets for radio-sensitization or biomarkers of radio-resistance. CONCLUSIONS: NF2 loss-of-function in the setting of hypoxia confers radiation resistance through a transcriptional program that promotes proliferation and DNA repair. Targeting molecular pathways identified by transcriptional profiling may improve local control in patients with radioresistant G2M.

Excitotoxic glutamate levels drive spinal cord ependymal stem cell proliferation and fate specification through CP-AMPAR signaling.

The adult spinal cord contains a population of ependymal-derived neural stem/progenitor cells (epNSPCs) that are normally quiescent, but are activated to proliferate, differentiate, and migrate after spinal cord injury. The mechanisms that regulate their response to injury cues, however, remain unknown. Here, we demonstrate that excitotoxic levels of glutamate promote the proliferation and astrocytic fate specification of adult spinal cord epNSPCs. We show that glutamate-mediated calcium influx through calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (CP-AMPARs) in concert with Notch signaling increases the proliferation of epNSPCs via pCREB, and induces astrocytic differentiation through Hes1 upregulation. Furthermore, the invivo targeting of this pathway via positive modulation of AMPARs after spinal cord injury enhances epNSPC proliferation, astrogliogenesis, neurotrophic factor production and increases neuronal survival. Our study uncovers an important mechanism by which CP-AMPARs regulate the growth and phenotype of epNSPCs, which can be targeted therapeutically to harness the regenerative potential of these cells after injury.

Expression analysis elucidates the roles of Nicastrin, Notch4, and Hes1 in prognosis and endocrine-therapy resistance in ER-positive breast cancer patients.

Although some proposed mechanisms responsible for tamoxifen resistance have already been present, further study is needed to determine the mechanisms underlying tamoxifen resistance more clearly. The critical role of Notch signaling has been described in promoting resistance in therapeutics, but there is little information about its role in tamoxifen resistance progression. In the present study, the expression of Notch pathway genes, including Notch4, nicastrin and the Notch downstream target Hes1 was evaluated using quantitative RT-PCR in 36 tamoxifen-resistant (TAM-R) and 36 tamoxifen-sensitive (TAM-S) patients. Expression data were correlated with the clinical outcome and survival of patients. mRNA levels of Notch4 (fold change = 2.7), nicastrin (fold change = 6.71), and Hes1 (fold change= 7.07) were significantly higher in TAM-R breast carcinoma patients compared to sensitive cases. We confirmed all these genes were co-expressed. Hence, it seems that Notch signaling is involved in tamoxifen resistance in our TAM-R patients. Obtained results showed that Hes1, nicastrin, and Notch4 mRNA upregulation was correlated with the N stage. The extracapsular nodal extension was associated with nicastrin and Notch4 overexpression. Moreover, nicastrin overexpression was correlated with perineural invasion. Hes1 upregulation was also associated with nipple involvement. Finally, the Cox regression proportional hazard test revealed that overexpression of nicastrin was an independent worse survival factor. Presumably, upregulation of the Notch pathway may be involved in tamoxifen resistance in breast cancer patients.

Dietary Tryptophan‐Lactobacillus rhamnosus GG Interactions Modify Intestinal Differentiation and Function

Although the influence of the gut microbiota on structure and proliferation of intestinal epithelial cells has been established, there is disconcordance on information related to cell type differentiation, because most studies on probiotics reflected an outcome from interactions among Lactobacillus, numerous existing microbes, and the host, with limited insight on the specific impact of Lactobacilli spp. For example, L. reuteri enhanced goblet and Paneth cell differentiation in intestine of conventionally‐raised chickens with an established commensal gut microbiota, confounding results. Here we fed gnotobiotic mice with tryptophan (t+) or trp‐free (t–) diets, followed by monocolonization with LGG (L+, ATCC 53103) or without (control, L–) for a total of 4 groups (L+t+, L+t–, L–t+, L–,t–), then ileum transcriptome was analyzed 3 wk later. L– mice remained germ‐free throughout while only LGG was associated with L+. Principal component analysis shows L+ or t+ by itself to modestly cluster away from L–t–, but the cluster depicting the combination of L+t+ was far removed from the others. The heatmap of whole ileum transcriptome shows several distinct groups of genes affected by t+ or by L+ alone. However, the simultaneous impact of L+t+ dramatically upregulates numerous gene clusters while downregulating a few. Volcano plots and Venn diagrams comparing L–t– with L–t+, or L+t– with L–t– indicate ~2300 unique genes affected by L+ (LGG) or t+ (tryptophan) alone. Comparisons between L+t+ and L+t– (effect of t with L) or between L+t+ and L–t+ (effect of L with t) each impact >3800 genes, suggesting that synergistic interactions between L+ and t+ primarily underlie the probiotic impact ascribed to LGG and dietary t. Many of the genes upregulated by L+t+ have functions typical of mature enterocytes: tight junctions, brush border membrane transporters and enzymes, intestinal bile acid metabolism, lipid synthesis and fatty acid b‐oxidation. Many downregulated genes are antimicrobial and secreted peptides typical of differentiated Paneth and goblet cells. This latter result was recapitulated when reexamined in conventional mice perfused for 4 h with LGG, as expression of many defensins decreased by >10‐fold, suggesting not only that this probiotic’s effects can arise from both acute ex vivo and chronic in vivo interactions with the host, but also in hosts housing a complex microbiota. Remarkably, Notch ligands Dll1 and Dll4 typically expressed in Paneth cells as well as Yap1, Axin2 and Ctnnb1 are upregulated in L+t+ ileum, suggesting downstream upregulation of Hes1 and repression of Atoh1, leading to suppression of the secretory lineage. In conclusion, LGG monocolonization may lead to synthesis of t+‐derived metabolites by both host and bacteria, leading to an enhancement of absorptive enterocyte functions and suppression of those by goblet and Paneth cells.

RASSF1A disrupts the NOTCH signaling axis via SNURF/RNF4-mediated ubiquitination of HES1.

RASSF1A promoter methylation has been correlated with tumor dedifferentiation and aggressive oncogenic behavior. Nevertheless, the underlying mechanism of RASSF1A-dependent tumor dedifferentiation remains elusive. Here, we show that RASSF1A directly uncouples the NOTCH-HES1 axis, a key suppressor of differentiation. Interestingly, the crosstalk of RASSF1A with HES1 occurs independently from the signaling route connecting RASSF1A with the Hippo pathway. At the molecular level, we demonstrate that RASSF1A acts as a scaffold essential for the SUMO-targeted E3 ligase SNURF/RNF4 to target HES1 for degradation. The reciprocal relationship between RASSF1A and HES1 is evident across a wide range of human tumors, highlighting the clinical significance of the identified pathway. We show that HES1 upregulation in a RASSF1A-depleted environment renders cells non-responsive to the downstream effects of γ-secretase inhibitors (GSIs) which restrict signaling at the level of the NOTCH receptor. Taken together, we report a mechanism through which RASSF1A exerts autonomous regulation of the critical Notch effector HES1, thus classifying RASSF1A expression as an integral determinant of the clinical effectiveness of Notch inhibitors.

Co-Culture of Primary Human Coronary Artery and Internal Thoracic Artery Endothelial Cells Results in Mutually Beneficial Paracrine Interactions.

Although saphenous veins (SVs) are commonly used as conduits for coronary artery bypass grafting (CABG), internal thoracic artery (ITA) grafts have significantly higher long-term patency. As SVs and ITA endothelial cells (ECs) have a considerable level of heterogeneity, we suggested that synergistic paracrine interactions between CA and ITA ECs (HCAECs and HITAECs, respectively) may explain the increased resistance of ITA grafts and adjacent CAs to atherosclerosis and restenosis. In this study, we measured the gene and protein expression of the molecules responsible for endothelial homeostasis, pro-inflammatory response, and endothelial-to-mesenchymal transition in HCAECs co-cultured with either HITAECs or SV ECs (HSaVECs) for an ascending duration. Upon the co-culture, HCAECs and HITAECs showed augmented expression of endothelial nitric oxide synthase (eNOS) and reduced expression of endothelial-to-mesenchymal transition transcription factors Snail and Slug when compared to the HCAEC–HSaVEC model. HCAECs co-cultured with HITAECs demonstrated an upregulation of HES1, a master regulator of arterial specification, of which the expression was also exclusively induced in HSaVECs co-cultured with HCAECs, suggestive of their arterialisation. In addition, co-culture of HCAECs and HITAECs promoted the release of pro-angiogenic molecules. To conclude, co-culture of HCAECs and HITAECs results in reciprocal and beneficial paracrine interactions that might contribute to the better performance of ITA grafts upon CABG.

Elevated miR-216b Enhances Cisplatin-Induced Apoptosis in Osteosarcoma by Downregulating JMJD2C and Regulating HIF-1α/HES1 Signaling Axis

Background: Cisplatin-based chemotherapy is the standard regimen for osteosarcoma (OS). However, chemoresistance to cisplatin commonly contributes to treatment failure and poor prognosis for metastatic OS patients. The study aims to identify whether miR-216b is dysregulated in OS and its relation to OS cell resistance to cisplatin. Methods: Tumor and paracancerous tissues were collected from OS patients to determine expression patterns of miR-216b and JMJD2C. Pearson correlation analysis was used to evaluate the expression between miR-216b and JMJD2C. CCK8 assay and flow cytometry were used to determine cell viability and apoptosis. Targeting relationship of miR-216b and JMJD2C was determined by dual luciferase reporter assay. Co-immunoprecipitation (IP) assay was used to determine binding between JMJD2C and HIF1α. Chromatin IP (ChIP)-qPCR was used to examine the level of HES1 promoter fragment enriched by H3K9me3 antibodies. Results: miR-216b expression was reduced in OS and positively correlated with patient survival. miR-216b overexpression further enhanced cisplatin-induced apoptosis in OS cells. miR-216b targeted and inhibited JMJD2C. JMJD2C bound and enhanced HIF1α to remove the H3K9 methylation modification at the HES1 promoter region, leading to upregulation of HES1. miR-216b overexpression further reduced cisplatin-induced decrease in tumor growth and weight in nude mice. HES1 overexpression weakened all effects of miR-216b in OS cells and in nude mice xenografts. Conclusion: miR-216b further enhances the effects of cisplatin through downregulating JMJD2C and regulating HIF1α/HES1 signaling axis in OS, suggesting that miR-216b may be an adjunct to cisplatin chemotherapy in the treatment of OS. Funding Statement: This study was supported by General Program of National Natural Science Foundation of China (No. 81572632 & No. 8187100734). Declaration of Interests: The author declares no competing interest exists. Ethics Approval Statement: Human tissue collection protocol was approved by Institutional ethics committee. All animal procedures were approved by Institutional Animal Care and Ethics Committee.

Notch signaling is involved in Fgf23 upregulation in osteocytes

Fgf23 acts as a phosphaturic factor secreted from osteocytes in bone, but the mechanism regulating Fgf23 is not fully understood. Here, we showed the colocalization of Fgf23, Notch, and Hes1, a downstream target of Notch signaling, in numerous osteocytes in cortical bone of femur in wild-type mice. We generated NICD (Notch intracellular domain)-transgenic mice driven by a 2.3 kb collagenα1 (I) (Col1a1) promoter fragment. Western blot and RT-PCR analyses revealed upregulation of Notch protein and mRNA levels in the bones of transgenic mice compared with those in wild-type mice. In the transgenic mice, immunohistochemical studies demonstrated that numerous osteocytes and osteoblasts express Notch in the rib, whereas only osteoblasts exhibit Notch in the femur. NICD-transgenic mice were characterized by upregulation of Fgf23 mRNA levels in the rib but not in the femur compared with that in wild type mice. These mice exhibited dwarfism associated with an osteomalacia phenotype. The expression of Alpl, Col1a1, and Bglap decreased in NICD-transgenic mice compared with wild-type mice. UMR-106 cells cultured on Jagged1-immobilized wells significantly increased Fgf23 expressions associating with upregulation of Hes1 and Hey1. These results imply that Notch signaling is a positive regulator for Fgf23 expression in osteocytes.

Glucocorticoid Resistance in IKZF1-Deleted BCP-ALL: It Is PTEN Again

▪Single copy deletions of IKZF1, which occur in 10-15% of all B cell precursor acute lymphoblastic leukemia (BCP-ALL) cases, are associated with a poor outcome. We previously showed that loss of IKZF1 dictates resistance to glucocorticoids (GC) in BCP-ALL cell lines, a knockout mouse model and ex-vivo analysis of primary leukemic cells. When we analyzed the initial response to prednisolone therapy, we found that pediatric patients who suffer from an IKZF1 deleted leukemia are strongly enriched in the poor responder group (14 vs 7%, p<0.05). Although we were able to show that glucocorticoid receptor (GR)-mediated transcription regulation is attenuated in IKZF1 deleted cells, in remained unclear how loss of IKZF1 affects GR signaling.In T-ALL, GC resistance is frequently induced by genomic mutations that result in hyperactivation of AKT. AKT mediated phosphorylation of the GR results in suppression of GR function and resistance to GC treatment. Although the genomic loci that are frequently mutated in T-ALL resulting in hyperactivation of AKT, such as PTEN, are unaffected in BCP-ALL, we tested whether aberrant activation of AKT may also cause resistance to GC in BCP-ALL. Indeed, both CRISPR/Cas9 induced knockout and shRNA mediated knockdown of IKZF1 resulted in activation of AKT in human BCP-ALL cell lines. This hyperactivation was also observed in splenic B cells isolated from Ikzf1+/- mice. Active AKT in turn promotes phosphorylation of the GR on Ser143. This phosphorylation inhibits GR function, at least in part, by preventing shuttling of the ligand bound protein to the nucleus.In order to understand how a single copy loss of IKZF1 activates AKT, we tested expression of upstream regulators of AKT activity and found a near complete loss of PTEN expression, the phosphatase that inhibits PI3K and AKT signaling. Indeed, shRNA mediated knockdown of PTEN in wildtype cells resulted in activation of AKT and induced resistance to GCs. Furthermore, in IKZF1+/- cells we observed an upregulation of HES1, a transcriptional factor that is known to repress expression of the PTEN gene. Of note, HES1 was previously identified as a target of IKZF1 mediated transcriptional repression in erythroid and T cells.To test whether this AKT mediated mechanism of GC resistance could be reverted through pharmacological inhibition, we tested the effect of AKT inhibitors on prednisolone induced apoptosis of human BCP-ALL cell lines (figure A). In contrast to control cells, where inhibition of AKT had little to no effect on the sensitivity to GC, in IKZF1 deleted cells AKT inhibition reverted the resistance phenotype to a level comparable to control cells. Importantly, also in patient derived xenografts we observed that AKT inhibition was able to sensitize cells to GC treatment (Figure B).In conclusion, we identified hyperactivation of AKT, as a result of aberrant HES1 expression, as the mechanism causing GC resistance in IKZF1 deleted BCP-ALL. The availability of AKT inhibitors that are under clinical evaluation, may allow the development of combination therapies that restore the response to GCs in IKZF1-deleted BCP-ALL.Figures:A) IKZF1, PTEN, AKT, pAKT(Ser473), pGR(Ser134) and GR protein expression levels of NALM6 IKZF1+/- cell lysates were analyzed by western blot. Non-targeting controls were used as control and actin was used as a loading control.B) NALM6 parental, non-targeting controls or IKZF1+/- cells were treated for 48 hours with increasing concentrations of prednisolone with or without 0.5µM AKT inhibitor MK2206 and analyzed using an MTT based viability assay. All values were normalized to untreated NALM6 cells. Error bars represent ± standard error of the mean (SEM).(C) hTERT immortalized MSCs were seeded in a 96 wells format and allowed to settle for 24 hours prior to the addition of BCP-ALL patient-derived xenografts (PDX). PDX cells were allowed to settle for 24 hours before prednisone was added in increasing concentrations with or without AKT inhibitor MK2206. After 3 days, sensitivity to treatment was measured by flowcytometry using an amine staining to test for membrane integrity as a measure of cell viability. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Upregulation of HES1 Promotes Cell Proliferation and Invasion in Breast Cancer as a Prognosis Marker and Therapy Target via the AKT Pathway and EMT Process.

HES1 is a transcriptional repressor involved in cell differentiation and proliferation as well as in various cancer developments, but its expression pattern and biological roles in breast cancer have not been examined. In this study, we assessed HES1 expression in breast cancer tissues using immunohistochemistry and Western blot analyses and investigated HES1 function using MTT and Matrigel invasion assays. Significant relationships were observed between HES1 upregulation and advanced TNM stage (p=0.011), node metastasis (p=0.043), negative oestrogen receptor expression (p=0.001) and triple-negative status (p=0.001). HES1 overexpression was correlated with poor prognosis in breast cancer patients (p<0.05). The MTT and Matrigel invasion assays showed that silencing HES1 in MDA-MB-231 cells decreased cell proliferation and invasion, whereas overexpression of HES1 in MCF-7 cells enhanced its proliferation and invasion. Further analyses showed that silencing HES1 downregulated p-AKT and impeded epithelial-mesenchymal transition (EMT), whereas overexpression of HES1 upregulated AKT phosphorylation and induced EMT. Our study demonstrated that HES1 upregulation is a predictor of poor prognosis in human breast cancers and might be a critical contributor to the proliferation and invasion of breast cancer cells. Moreover, the proportion of cells with overexpression of HES1 in triple-negative breast cancer (TNBC) samples was significantly higher. Thus, HES1 might be a potential therapeutic target in the treatment of TNBC.

Indirect immobilized Jagged1 suppresses cell cycle progression and induces odonto/osteogenic differentiation in human dental pulp cells

Notch signaling regulates diverse biological processes in dental pulp tissue. The present study investigated the response of human dental pulp cells (hDPs) to the indirect immobilized Notch ligand Jagged1 in vitro. The indirect immobilized Jagged1 effectively activated Notch signaling in hDPs as confirmed by the upregulation of HES1 and HEY1 expression. Differential gene expression profiling using an RNA sequencing technique revealed that the indirect immobilized Jagged1 upregulated genes were mainly involved in extracellular matrix organization, disease, and signal transduction. Downregulated genes predominantly participated in the cell cycle, DNA replication, and DNA repair. Indirect immobilized Jagged1 significantly reduced cell proliferation, colony forming unit ability, and the number of cells in S phase. Jagged1 treated hDPs exhibited significantly higher ALP enzymatic activity, osteogenic marker gene expression, and mineralization compared with control. Pretreatment with a γ-secretase inhibitor attenuated the Jagged1-induced ALP activity and mineral deposition. NOTCH2 shRNA reduced the Jagged1-induced osteogenic marker gene expression, ALP enzymatic activity, and mineral deposition. In conclusion, indirect immobilized Jagged1 suppresses cell cycle progression and induces the odonto/osteogenic differentiation of hDPs via the canonical Notch signaling pathway.

Reduced expression of the murine HLA-G homolog Qa-2 is associated with malignancy, epithelial-mesenchymal transition and stemness in breast cancer cells

Qa-2 is believed to mediate a protective immune response against cancer; however, little is known about the role of Qa-2 in tumorigenesis. Here, we used 4T1 breast cancer cells to study the involvement of Qa-2 in tumor progression in a syngeneic host. Qa-2 expression was reduced during in vivo tumor growth and in cell lines derived from 4T1-induced tumors. Tumor-derived cells elicited an epithelial-mesenchymal transition associated with upregulation of Zeb1 and Twist1/2 and enhanced tumor initiating and invasive capacities. Furthermore, these cells showed increased stem characteristics, as demonstrated by upregulation of Hes1, Sox2 and Oct3/4, and enrichment of CD44high/CD24median/low cells. Remarkably, Qa-2 cell-surface expression was excluded from the CD44high/CD24median/low subpopulation. Tumor-derived cells showed increased Src activity, and treatment of these cells with the Src kinase inhibitor PP2 enhanced Qa-2 but reduced Sox2 and CD44high/CD24median/low expression levels, suggesting that Src signaling, while positively associated with stemness, negatively regulates Qa-2 expression in breast cancer. Finally, overexpression of the Qa-2 family member Q7 on the cell surface slowed down in vivo tumor growth and reduced the metastatic potential of 4T1 cells. These results suggest an anti-malignant role for Qa-2 in breast cancer development, which appears to be absent from cancer stem cells.

The effect of Hes1 upregulation on neurogenesis after traumatic brain injury

Objective To investigate the effect of Hes1 upregulation by using an adonoviral vector containing mouse Hes1 gene in adult hippocampal neurogenesis following traumatic brain injury (TBI), a Morris water maze (MWM) test was employed to investigate the spatial learning and memory capacity of adult mice following injury. Methods One hundred and sixty mice were randomly allocated into four groups: sham-PBS group, sham-PBS-TBI group, Ad5-enhanced green fluorescent protein (EGFP)-TBI group, Ad5-Hes1-TBI group. The TBI model mouse was subjected to lateral fluid percussion injury of (202±2) kPa using a pre-calibrated fluid percussion injury device. Then, Ad5-mRNA and PBS were stereotaetic injected into the hippocampus of the adult C57BL/6 mice and their expressions in the hippocampus were detected. Western blotting and real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) methods were employed to detect the expression level of Hes1 on day 3 following TBI. We performed BrdU or DCX immunofluorescence staining on day 3 or 7 post TBI, to investigate the effect of Hes1 upregulation in adult hippocampal neurogenesis following TBI. Results FQ-PCR and Western blotting analysis suggested that Hes1 was up-regulated in overexpression group at mRNA (1.87±0.13 vs. 0.97±0.13, P=0.025) on day 3 post TBI and protein level; Immunofluorescence staining showed that a significant decrease in the total number of BrdU (+ ) and DCX (+ ) cells from the animals with Ad5-mHes1 treated on day 3 or 7 post injury. Morris water maze (MWM) test confirmed that Hes1 overexpression did not lead to a statistically significant change in EL and the target quadrant (P=0.062). Conclusion These results strongly suggested that increased expression of Hes1 may inhibit adult neurogenesis in DG of hippocampus after TBI and did not lead to a statistically significant change in the spatial learning and memory capacity of adult mice following injury. Key words: Hes1; Adult neurogenesis; Traumatic brain injury; Morris water maze

Cervical Cancer Stem Cells Selectively Overexpress HPV Oncoprotein E6 that Controls Stemness and Self-Renewal through Upregulation of HES1.

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.

Effect of Jagged-1 and Dll-1 on osteogenic differentiation by stem cells from human exfoliated deciduous teeth

ObjectiveThe aim of the present study was to determine the influence of Notch ligands, Jagged-1 and Dll-1, on osteogenic differentiation by stem cells from human exfoliated deciduous teeth. DesignNotch ligands were immobilized on tissue culture surface using an indirect affinity immobilization technique. Cells from the remaining of dental pulp tissues from human deciduous teeth were isolated and characterized using flow cytometry and differentiation assay. Alkaline phosphatase (ALP) enzymatic activity, osteogenic marker gene expression, and mineralization were determined using ALP assay, real-time polymerase chain reaction, and alizarin red staining, respectively. ResultsThe isolated cells exhibited CD44, CD90, and CD105 expression but lack of CD45 expression. Further, these cells were able to differentiate toward osteogenic lineage. The upregulation of HES-1 and HEY-1 was observed in those cells on Dll-1 and Jagged-1 coated surface. The significant increase of ALP activity and mineralization was noted in those cells seeded on Jagged-1 surface and these results were attenuated when cells were pretreated with gamma secretase inhibitor. The significant upregulation of ALP and collagen type I gene expression was also observed in those cells seeded on Jagged-1 surface. The inconsistent Dll-1 induced osteogenic differentiation was found and high Dll-1 immobilized dose (50nM) slightly enhanced alkaline phosphatase enzymatic activity. However, the statistical significant difference was not obtained as compared to the hFc control. ConclusionThe surface immobilization of Notch ligands, Jagged-1 and Dll-1, likely to enhance osteogenic differentiation of SHEDs. However, Jagged-1 had more ability in enhancing osteogenic differentiation than Dll-1 in our model.

TSG attenuates LPC-induced endothelial cells inflammatory damage through notch signaling inhibition.

Lysophosphatidylcholine (LPC) induces inflammation in endothelial cells (ECs) but the mechanism is not fully understood. The Notch signaling pathway is involved in chronic EC inflammation, but its functions in LPC-induced endothelial inflammatory damage and 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside's (TSG) protective effect during LPC-induced inflammatory damage in human umbilical vein endothelial cells (HUVECs) is largely unknown. We report that Notch signaling activation contributed to LPC-induced injury in HUVECs, and that TSG protected HUVECs from LPC-induced injury by antagonizing Notch signaling activation by LPC. γ-secretase inhibitor (DAPT), a specific inhibitor of the Notch signaling pathway, and Notch1 siRNA were used to inhibit Notch activity. HUVECs were exposed to LPC in the presence or absence of TSG, DAPT, and Notch1 siRNA. LPC treatment of HUVECs resulted in reduced cell viability, and Notch1 and Hes1 upregulation. Either silencing of Notch1 by siRNA or pharmacological inhibition of Notch signaling by DAPT prevented the loss of cell viability, and induction of apoptosis, and enhanced expression Notch1, Hes1 and MCP-1 by LPC in HUVECs. Similarly, TSG reduced LPC stimulation of Notch1, Hes1, and MCP-1 expression, prevented the release of IL-6 and CRP and rescued HUVECs from LPC-induced cell damage. Our data indicate that the Notch signaling pathway is a crucial mediator of endothelial inflammatory damage and that TSG protects against endothelial inflammatory damage by inhibiting the Notch signaling pathway. Our findings suggest that targeting Notch signaling by natural products such as TSG is a promising strategy for the prevention and treatment of chronic inflammation associated diseases, including atherosclerosis. © 2015 IUBMB Life, 68(1):37-50, 2016.

Hes1 triggers epithelial-mesenchymal transition (EMT)-like cellular marker alterations and promotes invasion and metastasis of nasopharyngeal carcinoma by activating the PTEN/AKT pathway.

Overexpression of the transcriptional factor Hes1 (hairy and enhancer of split-1) has been observed in numerous cancers, but the precise roles of Hes1 in epithelial-mesenchymal transition (EMT), cancer invasion and metastasis remain unknown. Our current study firstly revealed that Hes1 upregulation in a cohort of human nasopharyngeal carcinoma (NPC) biopsies is significantly associated with the EMT, invasive and metastatic phenotypes of cancer. In the present study, we found that Hes1 overexpression triggered EMT-like cellular marker alterations of NPC cells, whereas knockdown of Hes1 through shRNA reversed the EMT-like phenotypes, as strongly supported by Hes1-mediated EMT in NPC clinical specimens described above. Gain-of-function and loss-of-function experiments demonstrated that Hes1 promoted the migration and invasion of NPC cells in vitro. In addition, exogenous expression of Hes1 significantly enhanced the metastatic ability of NPC cells in vivo. Chromatin immunoprecipitation (ChIP) assays showed that Hes1 inhibited PTEN expression in NPC cells through binding to PTEN promoter region. Increased Hes1 expression and decreased PTEN expression were also observed in a cohort of NPC biopsies. Additional studies demonstrated that Hes1-induced EMT-like molecular changes and increased motility and invasion of NPC cells were mediated by PTEN. Taken together, our results suggest, for what we believe is the first time, that Hes1 plays an important role in the invasion and metastasis of NPC through inhibiting PTEN expression to trigger EMT-like phenotypes.

Lyso-Gb3 activates Notch1 in human podocytes.

Podocyte injury is an early feature of Fabry nephropathy, but the molecular mechanisms of podocyte injury are poorly understood. Lyso-Gb3 accumulates in serum in Fabry disease and increases extracellular matrix synthesis in podocytes. We explored the contribution of Notch1 signaling, a mediator of podocyte injury, to lyso-Gb3-elicited responses in cultured human podocytes. At clinically relevant concentrations, lyso-Gb3 activates podocyte Notch1 signaling, resulting in increased active Notch1 and HES1, a canonical Notch transcriptional target. A γ-secretase inhibitor or specific Notch1 small interfering RNA (siRNA) inhibited HES1 upregulation in response to lyso-Gb3. Notch1 siRNA or γ-secretase inhibition also prevented the lyso-Gb3-induced upregulation of Notch1, Notch ligand Jagged1 and chemokine (MCP1, RANTES) expression. Notch siRNA prevented the activation of nuclear factor kappa B (NFκB), and NFκB activation contributed to Notch1-mediated inflammatory responses as the NFκB inhibitor, parthenolide, prevented lyso-Gb3-induced chemokine upregulation. Notch1 also mediates fibrogenic responses in podocytes as Notch siRNA prevented lyso-Gb3 upregulation of fibronectin mRNA. Supporting the clinical relevance of cell culture findings, active Notch1, Jagged1 and HES1 were observed in Fabry kidney biopsies. Lyso-Gb3 elicited similar responses in mouse kidney. In conclusion, lyso-Gb3 promotes Notch1-mediated inflammatory and fibrogenic responses in podocytes that may contribute to Fabry nephropathy.

HES5Is a Key Mediator of Wnt-3a-Induced Neuronal Differentiation

Human neural stem/progenitor cell (hNPC)-derived neuronal progeny has been suggested as a promising cell source in a variety of neurodegenerative diseases. Understanding the underlying mechanisms that regulate neuronal differentiation is essential for efficient cell-based therapies. Wnt and Notch signaling has been shown to be crucial in this process. However, their interactions in the process of neuronal differentiation remain elusive. By using human fetal (ReNcell VM) and iPS-derived hNPCs we demonstrate that Wnt-3a immediately induced a transient HES1 upregulation and a sustained HES5 repression that was accompanied by upregulation of the proneural gene MASH1. Conversely, overexpression of HES5 resulted in reduced MASH1 expression. Remarkably, HES5 overexpression efficiently blocked Wnt-3a as well as γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT)-induced neuronal differentiation that was accompanied by a strong MASH1 downregulation thus directly linking HES5 repression/MASH1 induction to the proneurogenic effect of Wnt-3a. Stabilized β-catenin or treatment with the specific glycogen synthase kinase 3 beta (GSK3β) inhibitor SB-216763 failed to or only partially mimicked these effects, suggesting a GSK3β- and β-catenin-independent mechanism. Further, inhibition of Wnt-3a-LDL-receptor-related protein 5/6 (LRP5/6) interactions using Dickkopf-1 (Dkk-1) failed to inhibit the modulatory effect of Wnt-3a on HES1/5 and neuronal differentiation. Taken together, these data identify HES5 as a key mediator of the Wnt-3a proneurogenic effect occurring independently of the classical Wnt/β-catenin signaling cascade thus further deciphering crosstalk mechanisms of Wnt and Notch signaling pathways regulating cell fate of hNPCs.

Hes1 upregulation contributes to the development of FIP1L1-PDGRA–positive leukemia in blast crisis

We have previously shown that elevated expression of Hairy enhancer of split 1 (Hes1) contributes to blast crisis transition in Bcr-Abl-positive chronic myelogenous leukemia. Here we investigate whether Hes1 is involved in the development of other myeloid neoplasms. Notably, Hes1 expression was elevated in only a few cases of 65 samples with different types of myeloid neoplasms. Interestingly, elevated expression of Hes1 was found in two of five samples of Fip1-like1 platelet-derived growth factor receptor-α (FIP1L1-PDGFA)-positive myeloid neoplasms associated with eosinophilia. Whereas FIP1L1-PDGFRα alone induced acute T-cell leukemia or myeloproliferative neoplasms in mouse bone marrow transplantation models, mice transplanted with bone marrow cells expressing both Hes1 and FIP1L1-PDGFRα developed acute leukemia characterized by an expansion of myeloid blasts and leukemic cells without eosinophilic granules. FIP1L1-PDGFRα conferred cytokine-independent growth to Hes1-transduced common myeloid progenitors, interleukin-3-dependent cells. Imatinib inhibited the growth of common myeloid progenitors expressing Hes1 with FIP1L1-PDGFRα, but not with imatinib-resistant FIP1L1-PDGFRα mutants harboring T674I or D842V. In contrast, ponatinib efficiently eradicated leukemic cells expressing Hes1 and the imatinib-resistant FLP1L1-PDGFRΑ mutant in vitro and in vivo. Thus, we have established mouse models of FIP1L1-PDGFRA-positive leukemia in myeloid blast crisis, which will help elucidate the pathogenesis of the disease and develop a new treatment for it.