Dual Function of Notch Signaling in Cancer: Oncogene and Tumor Suppressor

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

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Notch pathway activation targets AML-initiating cell homeostasis and differentiation

Journal of Experimental Medicine ◽

10.1084/jem.20121484 ◽

2013 ◽

Vol 210 (2) ◽

pp. 301-319 ◽

Cited By ~ 94

Author(s):

Camille Lobry ◽

Panagiotis Ntziachristos ◽

Delphine Ndiaye-Lobry ◽

Philmo Oh ◽

Luisa Cimmino ◽

...

Keyword(s):

Tumor Suppressor ◽

Notch Signaling ◽

Myeloproliferative Neoplasms ◽

Notch Pathway ◽

Notch Signaling Pathway ◽

Notch Receptor ◽

Pathway Activation ◽

Function Models

Notch signaling pathway activation is known to contribute to the pathogenesis of a spectrum of human malignancies, including T cell leukemia. However, recent studies have implicated the Notch pathway as a tumor suppressor in myeloproliferative neoplasms and several solid tumors. Here we report a novel tumor suppressor role for Notch signaling in acute myeloid leukemia (AML) and demonstrate that Notch pathway activation could represent a therapeutic strategy in this disease. We show that Notch signaling is silenced in human AML samples, as well as in AML-initiating cells in an animal model of the disease. In vivo activation of Notch signaling using genetic Notch gain of function models or in vitro using synthetic Notch ligand induces rapid cell cycle arrest, differentiation, and apoptosis of AML-initiating cells. Moreover, we demonstrate that Notch inactivation cooperates in vivo with loss of the myeloid tumor suppressor Tet2 to induce AML-like disease. These data demonstrate a novel tumor suppressor role for Notch signaling in AML and elucidate the potential therapeutic use of Notch receptor agonists in the treatment of this devastating leukemia.

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Notch signaling in pancreatic cancer: oncogene or tumor suppressor?

Trends in Molecular Medicine ◽

10.1016/j.molmed.2013.03.003 ◽

2013 ◽

Vol 19 (5) ◽

pp. 320-327 ◽

Cited By ~ 63

Author(s):

Jacqueline L. Avila ◽

Joseph L. Kissil

Keyword(s):

Pancreatic Cancer ◽

Tumor Suppressor ◽

Notch Signaling

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New insights into radioresistance in breast cancer identify a dual function of miR‐122 as a tumor suppressor and oncomiR

Molecular Oncology ◽

10.1002/1878-0261.12483 ◽

2019 ◽

Vol 13 (5) ◽

pp. 1249-1267 ◽

Cited By ~ 12

Author(s):

Isidro X. Perez‐Añorve ◽

Claudia H. Gonzalez‐De la Rosa ◽

Ernesto Soto‐Reyes ◽

Fredy O. Beltran‐Anaya ◽

Oscar Del Moral‐Hernandez ◽

...

Keyword(s):

Breast Cancer ◽

Tumor Suppressor ◽

Dual Function

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

Blood ◽

10.1182/blood.v114.22.2388.2388 ◽

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.

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Retraction notice to “Identification of FOXN4 as a tumor suppressor of breast carcinogenesis via the activation of TP53 and deactivation of Notch signaling” [Gene 722 (2020) 144057]

Gene ◽

10.1016/j.gene.2020.145161 ◽

2021 ◽

Vol 769 ◽

pp. 145161

Author(s):

Xiao Wang ◽

Dan Su ◽

Zhiquan Qin ◽

Zheling Chen

Keyword(s):

Tumor Suppressor ◽

Notch Signaling ◽

Breast Carcinogenesis ◽

Retraction Notice

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

Blood ◽

10.1182/blood-2009-12-253419 ◽

2011 ◽

Vol 117 (10) ◽

pp. 2891-2900 ◽

Cited By ~ 33

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.

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