Cell Specific Consequences of Notch Signaling: PARP1/HES1 Interaction Reveals a Novel Tumor Suppressor Mechanism.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2388-2388
Author(s):  
Sankaranarayanan Kannan ◽  
Patrick A. Zweidler-McKay
Keyword(s):  
Tumor Suppressor ◽  
Notch Signaling ◽  
Lymphoblastic Leukemia ◽  
Growth Arrest ◽  
Protein Sequencing ◽  
The Novel ◽  
Cell Type ◽  
Adp Ribosylation ◽  
Suppressor Mechanism ◽  
Cell Type Specific

Abstract Abstract 2388 Poster Board II-365 The Notch signaling pathway is a critical regulator of cell fate determination and differentiation during development, which is highly cell type specific. Similarly, Notch signaling plays both oncogenic and tumor suppressor roles in a wide variety of malignancies, depending on cell type. In contrast to T cell acute lymphoblastic leukemia (T-ALL) where Notch activation promotes leukemogenesis, induction of Notch signaling in B-ALL leads to growth arrest and apoptosis. The Notch target gene Hairy/Enhancer of Split1 (HES1) is sufficient to reproduce this tumor suppressor phenotype in B-ALL, however the mechanism is not yet known. Here we report the novel finding that HES1 forms distinct complexes in B-ALL versus T-ALL. This suggests that HES1 interacting proteins may contribute to the cell-type specific consequences of Notch/HES1 signaling. During characterization of these complexes, we identified the novel interaction between HES1 and PARP1 through immunoprecipitation and MALDI-TOF protein sequencing. This interaction was dependent on the HES1 bHLH and Orange domains and PARP1 and HES1 co-localize to a genomic HES1 binding site by ChIP. This interaction both inhibits HES1 repressor function and induces PARP1 activation in B-ALL. HES1-induced PARP1 cleavage leads to enhanced poly ADP ribosylation of PARP1, consumption of NAD+, diminished ATP levels, and translocation of the Apoptosis Inducing Factor (AIF) from mitochondria to the nucleus, resulting in apoptosis in B-ALL, but not T-ALL. Importantly the potential therapeutic Notch agonist peptide “DSL” also induces cell-specific growth arrest and apoptosis (A+B), followed by poly-ADP ribosylation of PARP1 (C), and nuclear translocation of AIF in B-ALL but not T-ALL cells (D). These data reveal a novel interaction of HES1 and PARP1 in B-ALL which modulates the function of the HES1 transcriptional complex and signals through PARP1 to induce apoptosis. This novel tumor suppressor mechanism involving a Notch driven, cell-type specific pro-apoptotic pathway may lead to the development of Notch agonist-based cancer therapeutics. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Notch/HES1-mediated PARP1 activation: a cell type–specific mechanism for tumor suppression

Blood ◽  
2011 ◽  
Vol 117 (10) ◽  
pp. 2891-2900 ◽  
Author(s):  
Sankaranarayanan Kannan ◽  
Wendy Fang ◽  
Guangchun Song ◽  
Charles G. Mullighan ◽  
Richard Hammitt ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Suppressor ◽  
Notch Signaling ◽  
Lymphoblastic Leukemia ◽  
Cancer Therapeutics ◽  
The Novel ◽  
Cell Type ◽  
Interacting Protein ◽  
A Cell ◽  
Cell Type Specific

Abstract Notch signaling plays both oncogenic and tumor suppressor roles, depending on cell type. In contrast to T-cell acute lymphoblastic leukemia (ALL), where Notch activation promotes leukemogenesis, induction of Notch signaling in B-cell ALL (B-ALL) leads to growth arrest and apoptosis. The Notch target Hairy/Enhancer of Split1 (HES1) is sufficient to reproduce this tumor suppressor phenotype in B-ALL; however, the mechanism is not yet known. We report that HES1 regulates proapoptotic signals by the novel interacting protein Poly ADP-Ribose Polymerase1 (PARP1) in a cell type–specific manner. Interaction of HES1 with PARP1 inhibits HES1 function, induces PARP1 activation, and results in PARP1 cleavage in B-ALL. HES1-induced PARP1 activation leads to self-ADP ribosylation of PARP1, consumption of nicotinamide adenine dinucleotide+, diminished adenosine triphosphate levels, and translocation of apoptosis-inducing factor from mitochondria to the nucleus, resulting in apoptosis in B-ALL but not T-cell ALL. Importantly, induction of Notch signaling by the Notch agonist peptide Delta/Serrate/Lag-2 can reproduce these events and leads to B-ALL apoptosis. The novel interaction of HES1 and PARP1 in B-ALL modulates the function of the HES1 transcriptional complex and signals through PARP1 to induce apoptosis. This mechanism shows a cell type–specific proapoptotic pathway that may lead to Notch agonist–based cancer therapeutics.

Notch Signaling In B-ALL Reveals PLK1 As A Potential Therapeutic Target In B-ALL: PLK1-Selective Inhibitor Poloxin Modulates Cyclin B and P53 Pathways, Leading To Growth Arrest and Apoptosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2912-2912 ◽  
Author(s):  
Sankaranarayanan Kannan ◽  
Mandy A Hall ◽  
Leonard S Golfman ◽  
Patrick A Zweidler-McKay
Keyword(s):  
Cell Cycle ◽  
Notch Signaling ◽  
Growth Arrest ◽  
Selective Inhibitor ◽  
Cyclin B ◽  
Cell Type ◽  
Specific Effects ◽  
Cell Cycle Regulator ◽  
Cell Type Specific ◽  
Novel Therapeutic

Abstract Background Notch is a well-known oncogene in T-ALL, yet appears to have tumor suppressor effects in B-ALL. These cell type-specific effects of Notch signaling mirror consequences seen in early lymphocyte development and raises the question of how Notch leads to such divergent consequences in closely related cell types. In exploring these Notch mechanisms we discovered a B-ALL specific Notch-mediated reduction in the cell cycle regulator Polo-like kinase-1 (PLK1), revealing a novel targetable kinase in B-ALL. Approach To explore the consequences of Notch-mediated down regulation of cell cycle regulator kinase PLK1, we targeted PLK1 kinase function with the novel PLK1-selective inhibitor poloxin in human B-ALL lines. Results PLK1 is highly expressed in B-ALL verses normal tissues (panel A), correlates with cyclin B expression, is expressed >2-fold higher in B-ALL with t(1;19) than other B-ALL samples, and may predict response of ALL to methotrexate. In our panel of human B-ALL cell lines poloxin induced G2/M growth arrest and decreased cell number by >80% (panel B), and decreased survival in B-ALL cells (>75% AnnexinV+, panel C). PLK1 inhibition led to tumor suppressor p53 stabilization, revealing >5-fold increase in p53 protein levels following poloxin treatment in B-ALL (panel D). Mechanistically, PLK1 inhibition leads to both cytoplasmic re-localization of cyclin B, disrupting the CDC2-cyclinB complex, as well as phosphorylation of p53 at Ser20, which destabilizes p53-MDM2 interaction and thus accumulation of p53. Conclusions While exploring the mechanisms of cell type-specific effects of Notch signaling in ALL, we have found a novel therapeutic target, the cell cycle regulator PLK1. Our findings reveal a novel therapeutic approach whereby PLK1-selective inhibition via poloxin induces growth arrest and apoptosis in human B-ALL via consequences on cyclin B and p53 pathways. Disclosures: No relevant conflicts of interest to declare.

Notch/HES1 Signaling Stabilizes p53 Expression Via a Novel PARP1-Chfr-PLK1-Mediated Mechanism in B-ALL

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1292-1292
Author(s):  
Sankaranarayanan Kannan ◽  
Patrick A Zweidler-McKay
Keyword(s):  
Cell Cycle ◽  
T Cell ◽  
B Cell ◽  
Notch Signaling ◽  
Critical Role ◽  
Growth Arrest ◽  
Cyclin B ◽  
Cell Type ◽  
Cell Type Specific ◽  
Notch Activation

Abstract Abstract 1292 Background: Notch signaling contributes to T cell leukemogenesis. However, we have found that activation of Notch signaling in human B-ALL promotes growth arrest and apoptosis. These contrasting effects of Notch in B versus T cell ALL, mirror effects seen in early lymphocyte development. As the Notch receptors are common between T and B cells, we hypothesized that these differences rely on the cell-type specific downstream mechanisms. We previously reported a critical role for Notch/HES1-mediated activation of Poly ADP-Ribose Polymerase 1 (PARP1) function in this B cell specific mechanism. Approach: To explore the cell-type specific downstream mechanisms of Notch activation in B-ALL, we used cell fractionation, westerns and immunoprecipitation to identify cell cycle regulators which were altered by Notch activation via HES1 expression in human B-ALL lines. Results: Notch activation in a panel of human B-ALL lines led to consistent growth arrest and apoptosis. Indeed, ligands, activated receptors and the Notch target gene HES1 all induced these leukemia lihibiting effects in B-ALL but not T-ALL lines. In this study we report a mechanism whereby HES1-mediated activation of PARP1 leads to PARylation of the E3 ligase Checkpoint with FHA and RING finger (CHFR) (Panel A) which results in targeting and ubiquitination of the cell cycle regulator Polo-Like Kinase 1 (PLK1) (Panel B). PLK1 is highly expressed in B vs. T-ALL and plays a critical role in B cell growth and survival. Following Notch activation, loss of ubiquitionated PLK1 through proteosomal degradation leads to cell cycle arrest through two mechanisms, namely cytoplasmic relocalization of cyclin B, disrupting the CDC2-cyclinB complex, as well as phosphorylation of p53 at S20, which leads to decreased weakened p53-MDM2 interaction and accumulation of p53 (Panel C). siRNA to CHFR reveal that this mechanism is dependent on CHFR (Panel C). Importantly this mechanism is not seen in T-ALL cells as the activation of PARP1 by HES1 does not occur in T-ALL cells. Conclusions: Our findings reveal a novel molecular mechanism whereby Notch signaling induces disruption of the cell cycle in a cell type specific manner in B-ALL. Activation of PARP1, PARylation of CHFR, ubiquitination of PLK1 resulting in loss of nuclear cyclin B and accumulation of p53 demonstrates a series of events which can be initiated through activation of Notch in B-ALL. This mechanism reveals a potentially targetable approach to B-ALL. Disclosures: No relevant conflicts of interest to declare.

Notch Agonists: Emerging as a Feasible Therapeutic Approach in AML.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1419-1419 ◽  
Author(s):  
Robert M. Sutphin ◽  
Wendy Fang ◽  
Claudia Miller ◽  
Patrick A. Zweidler-McKay
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Notch Signaling ◽  
Cell Fate ◽  
Cell Lines ◽  
Therapeutic Approach ◽  
Caspase 3 ◽  
Growth Arrest ◽  
Notch Pathway ◽  
Fold Increase

Abstract Introduction: The Notch pathway regulates critical cell-fate decisions affecting the growth and development of human hematopoietic cells. Although Notch1 is a known T cell oncogene, we have discovered that Notch signaling behaves as a tumor suppressor in acute myeloblastic leukemia (AML) inducing growth arrest and apoptosis in both cell lines and patient samples. To characterize the mechanism of this effect we have evaluated the influence of the Notch pathway on key effectors of differentiation, cell cycle, and apoptosis in human AML. Results: Notch signaling induces rapid growth arrest and apoptosis in a panel of human AML cell lines representing a range of AML FAB subtypes (M2–M6). Specifically, activated Notch1 expression caused a 70–95% reduction in AML cells compared to controls (p<0.001) (Figure 1). Notch-mediated growth arrest occurred in 24–48 hours with cells accumulating in G0/G1. Apoptosis was demonstrated by a 3.8-fold increase in AnnexinV binding (p<0.004) and a 3-fold upregulation of caspase 3 activity (p=0.0002) within 24 hours. The caspase 3 activity was abolished by the caspase 8 inhibitor IETD (p<0.0001) suggesting a potential role for the extrinsic death pathway. We also found that all four Notch receptors (1–4) are capable of inducing this effect, as is the Notch target gene HES1, suggesting a generalized Notch tumor suppressor effect in AML. Furthermore, Notch signaling through HES1 modulates the expression of key regulators of myeloid differentiation and cell cycle progression including downregulation of CEBPα 2.5-fold (p<0.02) and upregulation of p21WAF1 6-fold (p<0.004) suggesting potential mechanisms. As a novel therapeutic approach, we synthesized Notch agonists which effectively induce Notch signaling with a >18-fold increase in HES1 expression (p<.0001). Exposure of human AML cell lines and primary patient AML samples to this Notch agonist for 24 hours led to a 3 to 9-fold increase in apoptosis (p<0.017) compared to controls (Figure 2). Conclusions: We report here that Notch signaling is a novel tumor suppressor pathway in human AML. We demonstrate how Notch agonists can be used to induce growth arrest and apoptosis in human AML cell lines and patient AML samples. As a regulator of cell fate, proliferation and differentiation, Notch effectively disrupts multiple pathways in AML. We propose that Notch agonists represent a novel and feasible therapeutic approach in AML. Pre-clinical evaluation is underway. Figure.1 Effect of Notch on growth of AML cells Figure.1. Effect of Notch on growth of AML cells Figure.2 Notch Agonist induces apoptosis in AML Figure.2. Notch Agonist induces apoptosis in AML

scholarly journals Ageing, Cellular Senescence and Neurodegenerative Disease

2018 ◽  
Vol 19 (10) ◽  
pp. 2937 ◽  
Author(s):  
Marios Kritsilis ◽  
Sophia V. Rizou ◽  
Paraskevi Koutsoudaki ◽  
Konstantinos Evangelou ◽  
Vassilis Gorgoulis ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Neurodegenerative Disease ◽  
Cellular Senescence ◽  
Biological Process ◽  
The Novel ◽  
Cell Type ◽  
Age Related ◽  
Cell Type Specific ◽  
First Time

Ageing is a major risk factor for developing many neurodegenerative diseases. Cellular senescence is a homeostatic biological process that has a key role in driving ageing. There is evidence that senescent cells accumulate in the nervous system with ageing and neurodegenerative disease and may predispose a person to the appearance of a neurodegenerative condition or may aggravate its course. Research into senescence has long been hindered by its variable and cell-type specific features and the lack of a universal marker to unequivocally detect senescent cells. Recent advances in senescence markers and genetically modified animal models have boosted our knowledge on the role of cellular senescence in ageing and age-related disease. The aim now is to fully elucidate its role in neurodegeneration in order to efficiently and safely exploit cellular senescence as a therapeutic target. Here, we review evidence of cellular senescence in neurons and glial cells and we discuss its putative role in Alzheimer’s disease, Parkinson’s disease and multiple sclerosis and we provide, for the first time, evidence of senescence in neurons and glia in multiple sclerosis, using the novel GL13 lipofuscin stain as a marker of cellular senescence.

scholarly journals Growth Arrest-Specific 2 Promotes the Growth of T-Cell Acute Lymphoblastic Leukemia Cells Via Its Regulation of CXCR4

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4081-4081
Author(s):  
Wenjuan Ma ◽  
Yan Wan ◽  
Haixia Zhou ◽  
Li Zhu ◽  
Yun Zhao
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Protein Expression ◽  
Notch Signaling ◽  
Lymphoblastic Leukemia ◽  
Growth Arrest ◽  
Jurkat Cells ◽  
Control Group ◽  
Migration Ability ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Growth arrest-specific 2 (GAS2) has multiple functions including the regulation of cell morphology, cell cycle, apoptosis and calpain activity.GAS2 has a dual function in cancer cells, however its expression and underlying mechanism in human T-cell acute lymphoblastic leukemia (T-ALL) remain unclear. In the present study, qRT-PCR analysis showed that GAS2 has significantly higher expression (155.5-fold, P=0.0048) in CD3+ cells from T-ALL patients (n=25) than healthy donors (n=13). GAS2 was present in Jurkat cells, while absent in MOLT-4 or HPB-ALL cells. A tiny CpG island of GAS2 was almost fully methylated in both MOLT-4 (100%) and HPB-ALL cells (80%), while 40% methylation in Jurkat cells; suggesting that DNA methylation played a subtle role in regulating GAS2 expression. Two independent shRNA sequences were delivered into Jurkat cells with lentiviral vector. GAS2 silencing inhibited the growth and colony-forming cell (CFC) production significantly. Conversely, GAS2 overexpression enhanced the growth and CFC production of both MOLT-4 and HPB-ALL cells. In addition, GAS2 overexpression promoted HPB-ALL cell induced leukemia in a xenoengraftment model (5 mice in each control group). In GAS2 expressed group, the disease latency was shortened, the splenomegaly was more severe than control group (0.35±0.04g vs. 0.27±0.05g), and more leukemic cells were present in bone marrow (85±3% vs. 45±7%). To obtain the molecular insights of how GAS2 acts, RNA-seq data comparing GAS2 silenced Jurkat cells with control cells were generated. Several Notch signaling molecules were inhibited, including NOTCH1, HES1 and HES4. Despite the differential expression of these transcripts was validated in Jurkat cells, GAS2 overexpression did not elevated the expression of these transcripts in MOLT-4 or HPB-ALL cells, suggesting GAS2 did not have a consistent impact on Notch signaling. However, we found that GAS2 silencing reduced CXCR4 protein expression in Jurkat cells and GAS2 overexpression enhanced CXCR4 protein expression in MOLT-4 cells, while CXCR4 transcript was not altered upon GAS2 manipulation. Consequently, GAS2 silencing significantly reduced migration ability of Jurkat cells and GAS2 overexpression enhanced migration ability of MOLT-4 cells. Overexpression of CXCR4 "rescued" the inhibited CFC production and migration upon GAS2 silencing. A truncated GAS2 (Δ171-313) coined as GAS2DN (dominant negative form of GAS2) has been known to inhibit normal function of GAS2. Herein, we showed that GAS2DN inhibited the growth of Jurkat cells and the expression of CXCR4. To delineate the role of calpain1 and calpain2 in GAS2 function, shRNA sequences against calpain1 and calpain2 was delivered into GAS2DN expressed Jurkat cells respectively, the results showed that calpain2 but not calpain1 silencing was able to enhance the cell growth and CXCR4 expression. Taken together, the present study has demonstrated that GAS2 is aberrantly expressed in human T-ALL cells, which promotes the growth of T-ALL cells partially via its post-transcriptional regulation of CXCR4 depending on calpain2 activity. These data provide new insights of the pathogenesis of T-ALL and possibly new clues to improve the management of the disease. Disclosures No relevant conflicts of interest to declare.

scholarly journals Cell-Type-Specific Differentiation and Molecular Profiles in Skin Transplantation: Implication of Medical Approach for Genetic Skin Diseases

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Noritaka Oyama ◽  
Fumio Kaneko
Keyword(s):  
Skin Diseases ◽  
Smooth Muscle Actin ◽  
Epidermal Keratinocytes ◽  
Skin Transplantation ◽  
The Novel ◽  
Cell Type ◽  
Skin Cell ◽  
Donor Skin ◽  
Cell Type Specific ◽  
Cell Phenotypes

Skin is highly accessible and valuable organ, which holds promise to accelerate the understanding of future medical innovation in association with skin transplantation, engineering, and wound healing. In skin transplantation biology, multistage and multifocal damages occur in both grafted donor and perilesional host skin and need to be repaired properly for the engraftment and maintenance of characteristic skin architecture. These local events are more unlikely to be regulated by the host immunity, because human skin transplantation has accomplished the donor skin engraftment onto the immunocompromised or immunosuppressive animals. Recent studies have emerged the importance of α-smooth muscle actin- (SMA-) positive myofibroblasts, via stage- and cell-specific contribution of TGFβ, PDGF, ET-1, CCN-2 signalling pathways, and mastocyte-derived mediators (e.g., histamine and tryptase), for the functional reorganisation of the grafted skin. Moreover, particular cell lineages from bone marrow (BM) cells have been shown to harbour the diferentiation capacity into multiple skin cell phenotypes, including epidermal keratinocytes and dermal endothelial cells and pericytes, undercontrolled by chemokines or cytokines. From a dermatological viewpoint, we review the recent update of cell-type- and molecular-specific action associated with reconstitution of the grafted skin and also focus on the novel application of BM transplantation medicine in genetic skin diseases.

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