Almagro, J.
Messal, H.A.
Elosegui-Artola, A.
van Rheenen, J.
Behrens, A.
(2022). Tissue architecture in tumor initiation and progression. Trends cancer,
Vol.8
(6),
pp. 494-505.
show abstract
The 3D architecture of tissues bearing tumors impacts on the mechanical microenvironment of cancer, the accessibility of stromal cells, and the routes of invasion. A myriad of intrinsic and extrinsic forces exerted by the cancer cells, the host tissue, and the molecular and cellular microenvironment modulate the morphology of the tumor and its malignant potential through mechanical, biochemical, genetic, and epigenetic cues. Recent studies have investigated how tissue architecture influences cancer biology from tumor initiation and progression to distant metastatic seeding and response to therapy. With a focus on carcinoma, the most common type of cancer, this review discusses the latest discoveries on how tumor architecture is built and how tissue morphology affects the biology and progression of cancer cells..
Lan, L.
Evan, T.
Li, H.
Hussain, A.
Ruiz, E.J.
Zaw Thin, M.
Ferreira, R.M.
Ps, H.
Riising, E.M.
Zen, Y.
Almagro, J.
Ng, K.W.
Soro-Barrio, P.
Nelson, J.
Koifman, G.
Carvalho, J.
Nye, E.L.
He, Y.
Zhang, C.
Sadanandam, A.
Behrens, A.
(2022). GREM1 is required to maintain cellular heterogeneity in pancreatic cancer. Nature,
Vol.607
(7917),
pp. 163-168.
Nelson, J.K.
Thin, M.Z.
Evan, T.
Howell, S.
Wu, M.
Almeida, B.
Legrave, N.
Koenis, D.S.
Koifman, G.
Sugimoto, Y.
Llorian Sopena, M.
MacRae, J.
Nye, E.
Howell, M.
Snijders, A.P.
Prachalias, A.
Zen, Y.
Sarker, D.
Behrens, A.
(2022). USP25 promotes pathological HIF-1-driven metabolic reprogramming and is a potential therapeutic target in pancreatic cancer. Nat commun,
Vol.13
(1),
p. 2070.
show abstract
Deubiquitylating enzymes (DUBs) play an essential role in targeted protein degradation and represent an emerging therapeutic paradigm in cancer. However, their therapeutic potential in pancreatic ductal adenocarcinoma (PDAC) has not been explored. Here, we develop a DUB discovery pipeline, combining activity-based proteomics with a loss-of-function genetic screen in patient-derived PDAC organoids and murine genetic models. This approach identifies USP25 as a master regulator of PDAC growth and maintenance. Genetic and pharmacological USP25 inhibition results in potent growth impairment in PDAC organoids, while normal pancreatic organoids are insensitive, and causes dramatic regression of patient-derived xenografts. Mechanistically, USP25 deubiquitinates and stabilizes the HIF-1α transcription factor. PDAC is characterized by a severely hypoxic microenvironment, and USP25 depletion abrogates HIF-1α transcriptional activity and impairs glycolysis, inducing PDAC cell death in the tumor hypoxic core. Thus, the USP25/HIF-1α axis is an essential mechanism of metabolic reprogramming and survival in PDAC, which can be therapeutically exploited..
Gribben, C.
Lambert, C.
Messal, H.A.
Hubber, E.-.
Rackham, C.
Evans, I.
Heimberg, H.
Jones, P.
Sancho, R.
Behrens, A.
(2021). Ductal Ngn3-expressing progenitors contribute to adult β cell neogenesis in the pancreas. Cell stem cell,
Vol.28
(11),
pp. 2000-2008.e4.
show abstract
Ductal cells have been proposed as a source of adult β cell neogenesis, but this has remained controversial. By combining lineage tracing, 3D imaging, and single-cell RNA sequencing (scRNA-seq) approaches, we show that ductal cells contribute to the β cell population over time. Lineage tracing using the Neurogenin3 (Ngn3)-CreERT line identified ductal cells expressing the endocrine master transcription factor Ngn3 that were positive for the δ cell marker somatostatin and occasionally co-expressed insulin. The number of hormone-expressing ductal cells was increased in Akita+/- diabetic mice, and ngn3 heterozygosity accelerated diabetes onset. scRNA-seq of Ngn3 lineage-traced islet cells indicated that duct-derived somatostatin-expressing cells, some of which retained expression of ductal markers, gave rise to β cells. This study identified Ngn3-expressing ductal cells as a source of adult β cell neogenesis in homeostasis and diabetes, suggesting that this mechanism, in addition to β cell proliferation, maintains the adult islet β cell population..
Khan, O.M.
Almagro, J.
Nelson, J.K.
Horswell, S.
Encheva, V.
Keyan, K.S.
Clurman, B.E.
Snijders, A.P.
Behrens, A.
(2021). Proteasomal degradation of the tumour suppressor FBW7 requires branched ubiquitylation by TRIP12. Nature communications,
Vol.12
(1),
pp. 2043-?.
show abstract
The tumour suppressor FBW7 is a substrate adaptor for the E3 ubiquitin ligase complex SKP1-CUL1-F-box (SCF), that targets several oncoproteins for proteasomal degradation. FBW7 is widely mutated and FBW7 protein levels are commonly downregulated in cancer. Here, using an shRNA library screen, we identify the HECT-domain E3 ubiquitin ligase TRIP12 as a negative regulator of FBW7 stability. We find that SCFFBW7-mediated ubiquitylation of FBW7 occurs preferentially on K404 and K412, but is not sufficient for its proteasomal degradation, and in addition requires TRIP12-mediated branched K11-linked ubiquitylation. TRIP12 inactivation causes FBW7 protein accumulation and increased proteasomal degradation of the SCFFBW7 substrate Myeloid Leukemia 1 (MCL1), and sensitizes cancer cells to anti-tubulin chemotherapy. Concomitant FBW7 inactivation rescues the effects of TRIP12 deficiency, confirming FBW7 as an essential mediator of TRIP12 function. This work reveals an unexpected complexity of FBW7 ubiquitylation, and highlights branched ubiquitylation as an important signalling mechanism regulating protein stability..
Ruiz, E.J.
Lan, L.
Diefenbacher, M.E.
Riising, E.M.
Da Costa, C.
Chakraborty, A.
Hoeck, J.D.
Spencer-Dene, B.
Kelly, G.
David, J.-.
Nye, E.
Downward, J.
Behrens, A.
(2021). JunD, not c-Jun, is the AP-1 transcription factor required for Ras-induced lung cancer. Jci insight,
Vol.6
(13).
show abstract
The AP-1 transcription factor c-Jun is required for Ras-driven tumorigenesis in many tissues and is considered as a classical proto-oncogene. To determine the requirement for c-Jun in a mouse model of K-RasG12D-induced lung adenocarcinoma, we inducibly deleted c-Jun in the adult lung. Surprisingly, we found that inactivation of c-Jun, or mutation of its JNK phosphorylation sites, actually increased lung tumor burden. Mechanistically, we found that protein levels of the Jun family member JunD were increased in the absence of c-Jun. In c-Jun-deficient cells, JunD phosphorylation was increased, and expression of a dominant-active JNKK2-JNK1 transgene further increased lung tumor formation. Strikingly, deletion of JunD completely abolished Ras-driven lung tumorigenesis. This work identifies JunD, not c-Jun, as the crucial substrate of JNK signaling and oncogene required for Ras-induced lung cancer..
Almagro, J.
Messal, H.A.
Zaw Thin, M.
van Rheenen, J.
Behrens, A.
(2021). Tissue clearing to examine tumour complexity in three dimensions. Nature reviews cancer,
Vol.21
(11),
pp. 718-730.
Ruiz, E.J.
Pinto-Fernandez, A.
Turnbull, A.P.
Lan, L.
Charlton, T.M.
Scott, H.C.
Damianou, A.
Vere, G.
Riising, E.M.
Da Costa, C.
Krajewski, W.W.
Guerin, D.
Kearns, J.D.
Ioannidis, S.
Katz, M.
McKinnon, C.
O'Connell, J.
Moncaut, N.
Rosewell, I.
Nye, E.
Jones, N.
Heride, C.
Gersch, M.
Wu, M.
Dinsmore, C.J.
Hammonds, T.R.
Kim, S.
Komander, D.
Urbe, S.
Clague, M.J.
Kessler, B.M.
Behrens, A.
(2021). USP28 deletion and small-molecule inhibition destabilizes c-MYC and elicits regression of squamous cell lung carcinoma. Elife,
Vol.10.
show abstract
Lung squamous cell carcinoma (LSCC) is a considerable global health burden, with an incidence of over 600,000 cases per year. Treatment options are limited, and patient's 5-year survival rate is less than 5%. The ubiquitin-specific protease 28 (USP28) has been implicated in tumourigenesis through its stabilization of the oncoproteins c-MYC, c-JUN, and Δp63. Here, we show that genetic inactivation of Usp28-induced regression of established murine LSCC lung tumours. We developed a small molecule that inhibits USP28 activity in the low nanomole range. While displaying cross-reactivity against the closest homologue USP25, this inhibitor showed a high degree of selectivity over other deubiquitinases. USP28 inhibitor treatment resulted in a dramatic decrease in c-MYC, c-JUN, and Δp63 proteins levels and consequently induced substantial regression of autochthonous murine LSCC tumours and human LSCC xenografts, thereby phenocopying the effect observed by genetic deletion. Thus, USP28 may represent a promising therapeutic target for the treatment of squamous cell lung carcinoma..
Messal, H.A.
Almagro, J.
Zaw Thin, M.
Tedeschi, A.
Ciccarelli, A.
Blackie, L.
Anderson, K.I.
Miguel-Aliaga, I.
van Rheenen, J.
Behrens, A.
(2020). Antigen retrieval and clearing for whole-organ immunofluorescence by FLASH. ,
Vol.16
(1),
pp. 239-262.
show abstract
Advances in light-sheet and confocal microscopy now allow imaging of cleared large biological tissue samples and enable the 3D appreciation of cell and protein localization in their native organ environment. However, the sample preparations for such imaging are often onerous, and their capability for antigen detection is limited. Here, we describe FLASH (fast light-microscopic analysis of antibody-stained whole organs), a simple, rapid, fully customizable technique for molecular phenotyping of intact tissue volumes. FLASH utilizes non-degradative epitope recovery and membrane solubilization to enable the detection of a multitude of membranous, cytoplasmic and nuclear antigens in whole mouse organs and embryos, human biopsies, organoids and Drosophila. Retrieval and immunolabeling of epithelial markers, an obstacle for previous clearing techniques, can be achieved with FLASH. Upon volumetric imaging, FLASH-processed samples preserve their architecture and integrity and can be paraffin-embedded for subsequent histopathological analysis. The technique can be performed by scientists trained in light microscopy and yields results in <1 week..
Ruiz, E.J.
Diefenbacher, M.E.
Nelson, J.K.
Sancho, R.
Pucci, F.
Chakraborty, A.
Moreno, P.
Annibaldi, A.
Liccardi, G.
Encheva, V.
Mitter, R.
Rosenfeldt, M.
Snijders, A.P.
Meier, P.
Calzado, M.A.
Behrens, A.
(2019). LUBAC determines chemotherapy resistance in squamous cell lung cancer. The journal of experimental medicine,
Vol.216
(2),
pp. 450-465.
show abstract
Lung squamous cell carcinoma (LSCC) and adenocarcinoma (LADC) are the most common lung cancer subtypes. Molecular targeted treatments have improved LADC patient survival but are largely ineffective in LSCC. The tumor suppressor FBW7 is commonly mutated or down-regulated in human LSCC, and oncogenic KRasG12D activation combined with Fbxw7 inactivation in mice (KF model) caused both LSCC and LADC. Lineage-tracing experiments showed that CC10+, but not basal, cells are the cells of origin of LSCC in KF mice. KF LSCC tumors recapitulated human LSCC resistance to cisplatin-based chemotherapy, and we identified LUBAC-mediated NF-κB signaling as a determinant of chemotherapy resistance in human and mouse. Inhibition of NF-κB activation using TAK1 or LUBAC inhibitors resensitized LSCC tumors to cisplatin, suggesting a future avenue for LSCC patient treatment..
Messal, H.A.
Alt, S.
Ferreira, R.M.
Gribben, C.
Wang, V.M.
Cotoi, C.G.
Salbreux, G.
Behrens, A.
(2019). Tissue curvature and apicobasal mechanical tension imbalance instruct cancer morphogenesis. Nature,
Vol.566
(7742),
pp. 126-130.
show abstract
Tubular epithelia are a basic building block of organs and a common site of cancer occurrence1-4. During tumorigenesis, transformed cells overproliferate and epithelial architecture is disrupted. However, the biophysical parameters that underlie the adoption of abnormal tumour tissue shapes are unknown. Here we show in the pancreas of mice that the morphology of epithelial tumours is determined by the interplay of cytoskeletal changes in transformed cells and the existing tubular geometry. To analyse the morphological changes in tissue architecture during the initiation of cancer, we developed a three-dimensional whole-organ imaging technique that enables tissue analysis at single-cell resolution. Oncogenic transformation of pancreatic ducts led to two types of neoplastic growth: exophytic lesions that expanded outwards from the duct and endophytic lesions that grew inwards to the ductal lumen. Myosin activity was higher apically than basally in wild-type cells, but upon transformation this gradient was lost in both lesion types. Three-dimensional vertex model simulations and a continuum theory of epithelial mechanics, which incorporate the cytoskeletal changes observed in transformed cells, indicated that the diameter of the source epithelium instructs the morphology of growing tumours. Three-dimensional imaging revealed that-consistent with theory predictions-small pancreatic ducts produced exophytic growth, whereas large ducts deformed endophytically. Similar patterns of lesion growth were observed in tubular epithelia of the liver and lung; this finding identifies tension imbalance and tissue curvature as fundamental determinants of epithelial tumorigenesis..
Wang, V.M.
Ferreira, R.M.
Almagro, J.
Evan, T.
Legrave, N.
Zaw Thin, M.
Frith, D.
Carvalho, J.
Barry, D.J.
Snijders, A.P.
Herbert, E.
Nye, E.L.
MacRae, J.I.
Behrens, A.
(2019). CD9 identifies pancreatic cancer stem cells and modulates glutamine metabolism to fuel tumour growth. Nature cell biology,
Vol.21
(11),
pp. 1425-1435.
Foster, H.
Ruiz, E.J.
Moore, C.
Stamp, G.W.
Nye, E.L.
Li, N.
Pan, Y.
He, Y.
Downward, J.
Behrens, A.
(2019). ATMIN Is a Tumor Suppressor Gene in Lung Adenocarcinoma. Cancer research,
Vol.79
(20),
pp. 5159-5166.
show abstract
Tumor cells proliferate rapidly and thus are frequently subjected to replication stress and the risk of incomplete duplication of the genome. Fragile sites are replicated late, making them more vulnerable to damage when DNA replication fails to complete. Therefore, genomic alterations at fragile sites are commonly observed in tumors. FRA16D is one of the most common fragile sites in lung cancer, however, the nature of the tumor suppressor genes affected by FRA16D alterations has been controversial. Here, we show that the ATMIN gene, which encodes a cofactor required for activation of ATM kinase by replication stress, is located close to FRA16D and is commonly lost in lung adenocarcinoma. Low ATMIN expression was frequently observed in human lung adenocarcinoma tumors and was associated with reduced patient survival, suggesting that ATMIN functions as a tumor suppressor in lung adenocarcinoma. Heterozygous Atmin deletion significantly increased tumor cell proliferation, tumor burden, and tumor grade in the LSL-KRasG12D; Trp53 F/F (KP) mouse model of lung adenocarcinoma, identifying ATMIN as a haploinsufficient tumor suppressor. ATMIN-deficient KP lung tumor cells showed increased survival in response to replication stress and consequently accumulated DNA damage. Thus, our data identify ATMIN as a key gene affected by genomic deletions at FRA16D in lung adenocarcinoma. SIGNIFICANCE: These findings identify ATMIN as a tumor suppressor in LUAD; fragility at chr16q23 correlates with loss of ATMIN in human LUAD and deletion of Atmin increases tumor burden in a LUAD mouse model..
Khan, O.M.
Carvalho, J.
Spencer-Dene, B.
Mitter, R.
Frith, D.
Snijders, A.P.
Wood, S.A.
Behrens, A.
(2018). The deubiquitinase USP9X regulates FBW7 stability and suppresses colorectal cancer. The journal of clinical investigation,
Vol.128
(4),
pp. 1326-1337.
show abstract
The tumor suppressor FBW7 targets oncoproteins such as c-MYC for ubiquitylation and is mutated in several human cancers. We noted that in a substantial percentage of colon cancers, FBW7 protein is undetectable despite the presence of FBW7 mRNA. To understand the molecular mechanism of FBW7 regulation in these cancers, we employed proteomics and identified the deubiquitinase (DUB) USP9X as an FBW7 interactor. USP9X antagonized FBW7 ubiquitylation, and Usp9x deletion caused Fbw7 destabilization. Mice lacking Usp9x in the gut showed reduced secretory cell differentiation and increased progenitor proliferation, phenocopying Fbw7 loss. In addition, Usp9x inactivation impaired intestinal regeneration and increased tumor burden in colitis-associated intestinal cancer. c-Myc heterozygosity abrogated increased progenitor proliferation and tumor burden in Usp9x-deficient mice, suggesting that Usp9x suppresses tumor formation by regulating Fbw7 protein stability and thereby reducing c-Myc. Thus, we identify a tumor suppressor mechanism in the mammalian intestine that arises from the posttranslational regulation of FBW7 by USP9X independent of somatic FBW7 mutations..
Ferreira, R.M.
Sancho, R.
Messal, H.A.
Nye, E.
Spencer-Dene, B.
Stone, R.K.
Stamp, G.
Rosewell, I.
Quaglia, A.
Behrens, A.
(2017). Duct- and Acinar-Derived Pancreatic Ductal Adenocarcinomas Show Distinct Tumor Progression and Marker Expression. Cell reports,
Vol.21
(4),
pp. 966-978.
Cremona, C.A.
Sancho, R.
Diefenbacher, M.E.
Behrens, A.
(2016). Fbw7 and its counteracting forces in stem cells and cancer: Oncoproteins in the balance. Seminars in cancer biology,
Vol.36,
pp. 52-61.
Gruber, R.
Panayiotou, R.
Nye, E.
Spencer-Dene, B.
Stamp, G.
Behrens, A.
(2016). YAP1 and TAZ Control Pancreatic Cancer Initiation in Mice by Direct Up-regulation of JAK–STAT3 Signaling. Gastroenterology,
Vol.151
(3),
pp. 526-539.
Blaas, L.
Pucci, F.
Messal, H.A.
Andersson, A.B.
Josue Ruiz, E.
Gerling, M.
Douagi, I.
Spencer-Dene, B.
Musch, A.
Mitter, R.
Bhaw, L.
Stone, R.
Bornhorst, D.
Sesay, A.K.
Jonkers, J.
Stamp, G.
Malanchi, I.
Toftgård, R.
Behrens, A.
(2016). Lgr6 labels a rare population of mammary gland progenitor cells that are able to originate luminal mammary tumours. Nature cell biology,
Vol.18
(12),
pp. 1346-1356.
Blake, S.M.
Stricker, S.H.
Halavach, H.
Poetsch, A.R.
Cresswell, G.
Kelly, G.
Kanu, N.
Marino, S.
Luscombe, N.M.
Pollard, S.M.
Behrens, A.
(2016). Inactivation of the ATMIN/ATM pathway protects against glioblastoma formation. Elife,
Vol.5.
show abstract
Glioblastoma multiforme (GBM) is the most aggressive human primary brain cancer. Using a Trp53-deficient mouse model of GBM, we show that genetic inactivation of the Atm cofactor Atmin, which is dispensable for embryonic and adult neural development, strongly suppresses GBM formation. Mechanistically, expression of several GBM-associated genes, including Pdgfra, was normalized by Atmin deletion in the Trp53-null background. Pharmacological ATM inhibition also reduced Pdgfra expression, and reduced the proliferation of Trp53-deficient primary glioma cells from murine and human tumors, while normal neural stem cells were unaffected. Analysis of GBM datasets showed that PDGFRA expression is also significantly increased in human TP53-mutant compared with TP53-wild-type tumors. Moreover, combined treatment with ATM and PDGFRA inhibitors efficiently killed TP53-mutant primary human GBM cells, but not untransformed neural stem cells. These results reveal a new requirement for ATMIN-dependent ATM signaling in TP53-deficient GBM, indicating a pro-tumorigenic role for ATM in the context of these tumors..
Anjos-Afonso, F.
Loizou, J.I.
Bradburn, A.
Kanu, N.
Purewal, S.
Da Costa, C.
Bonnet, D.
Behrens, A.
(2016). Perturbed hematopoiesis in mice lacking ATMIN. Blood,
Vol.128
(16),
pp. 2017-2021.
show abstract
Key Points
ATMIN deletion using Vav-Cre causes chronic leukopenia, with fewer B cells and common myeloid progenitors. Long-term HSCs in ATMIN-deficient mice show increased cell cycling and are more prone to exhaustion under stress..
Kanu, N.
Zhang, T.
Burrell, R.A.
Chakraborty, A.
Cronshaw, J.
DaCosta, C.
Grönroos, E.
Pemberton, H.N.
Anderton, E.
Gonzalez, L.
Sabbioneda, S.
Ulrich, H.D.
Swanton, C.
Behrens, A.
(2016). RAD18, WRNIP1 and ATMIN promote ATM signalling in response to replication stress. Oncogene,
Vol.35
(30),
pp. 4009-4019.
Diefenbacher, M.E.
Chakraborty, A.
Blake, S.M.
Mitter, R.
Popov, N.
Eilers, M.
Behrens, A.
(2015). Usp28 Counteracts Fbw7 in Intestinal Homeostasis and Cancer. Cancer research,
Vol.75
(7),
pp. 1181-1186.
show abstract
Abstract
The stability of several oncoproteins, including c-Myc, is regulated by ubiquitin-dependent degradation mediated by the SCF(Fbw7) ubiquitin ligase. This activity is antagonized by the deubiquitinase Usp28, which is highly expressed in murine and human intestinal cancers. Usp28 was previously shown to interact with its substrates via a “piggyback” interaction with Fbw7, which suggested that Fbw7 is required for Usp28 activity. Unexpectedly, we found that genetic deletion of Usp28 rescued the lethality of Fbw7-deficient primary fibroblasts. Moreover, Usp28 inactivation in the intestine (Usp28ΔIEC) ameliorated the hyperproliferation and the impaired goblet and Paneth cell differentiation observed in Fbw7ΔIEC mice. The aggressive intestinal tumor formation of APCMin/+; Fbw7ΔIEC mice was restrained when Usp28 was inactivated concomitantly. In both fibroblasts and intestinal cells, Usp28 deficiency corrected the accumulation of SCF(Fbw7) substrate proteins, including NICD1, c-Jun, and c-Myc. These findings suggested that Usp28 function does not depend on the presence of Fbw7, but instead independently recognizes and deubiquitylates the same substrates as SCF(Fbw7). Fbw7 binds to a phosphorylated motif termed the phosphodegron and we found that Usp28 also interacted with this same motif, but only when it is unphosphorylated, offering a mechanistic explanation for identical substrate selection by Fbw7 and Usp28. Our results indicate an unusually direct antagonism between an E3 ligase and a deubiquitinase, Fbw7 and Usp28, in modulating intestinal homeostasis and cancer. Cancer Res; 75(7); 1181–6. ©2015 AACR..
Sancho, R.
Cremona, C.A.
Behrens, A.
(2015). Stem cell and progenitor fate in the mammalian intestine: Notch and lateral inhibition in homeostasis and disease. Embo reports,
Vol.16
(5),
pp. 571-581.
Chakraborty, A.
Diefenbacher, M.E.
Mylona, A.
Kassel, O.
Behrens, A.
(2015). The E3 ubiquitin ligase Trim7 mediates c-Jun/AP-1 activation by Ras signalling. Nat commun,
Vol.6,
p. 6782.
show abstract
The c-Jun/AP-1 transcription factor controls key cellular behaviours, including proliferation and apoptosis, in response to JNK and Ras/MAPK signalling. While the JNK pathway has been well characterized, the mechanism of activation by Ras was elusive. Here we identify the uncharacterized ubiquitin ligase Trim7 as a critical component of AP-1 activation via Ras. We found that MSK1 directly phosphorylates Trim7 in response to direct activation by the Ras-Raf-MEK-ERK pathway, and this modification stimulates Trim7 E3 ubiquitin ligase activity. Trim7 mediates Lys63-linked ubiquitination of the AP-1 co-activator RACO-1, leading to RACO-1 protein stabilization. Consequently, Trim7 depletion reduces RACO-1 levels and AP-1-dependent gene expression. Moreover, transgenic overexpression of Trim7 increases lung tumour burden in a Ras-driven cancer model, and knockdown of Trim7 in established xenografts reduces tumour growth. Thus, phosphorylation-ubiquitination crosstalk between MSK1, Trim7 and RACO-1 completes the long sought-after mechanism linking growth factor signalling and AP-1 activation..
Diefenbacher, M.E.
Popov, N.
Blake, S.M.
Schülein-Völk, C.
Nye, E.
Spencer-Dene, B.
Jaenicke, L.A.
Eilers, M.
Behrens, A.
(2014). The deubiquitinase USP28 controls intestinal homeostasis and promotes colorectal cancer. Journal of clinical investigation,
Vol.124
(8),
pp. 3407-3418.
Behrens, A.
van Deursen, J.M.
Rudolph, K.L.
Schumacher, B.
(2014). Impact of genomic damage and ageing on stem cell function. Nature cell biology,
Vol.16
(3),
pp. 201-207.
Sancho, R.
Gruber, R.
Gu, G.
Behrens, A.
(2014). Loss of Fbw7 Reprograms Adult Pancreatic Ductal Cells into α, δ, and β Cells. Cell stem cell,
Vol.15
(2),
pp. 139-153.
Zhang, T.
Cronshaw, J.
Kanu, N.
Snijders, A.P.
Behrens, A.
(2014). UBR5-mediated ubiquitination of ATMIN is required for ionizing radiation-induced ATM signaling and function. Proceedings of the national academy of sciences,
Vol.111
(33),
pp. 12091-12096.
show abstract
Significance
The checkpoint kinase ATM directs the cellular response to ionizing radiation (IR) by localizing to DNA damage sites and actively phosphorylating proteins involved in repair and survival. ATM is recruited and activated at damage sites via an interaction with the Mre11/Rad50/NBS1 (MRN) complex. We have previously shown that an alternative ATM binding partner, ATMIN, competitively inhibits this interaction, suggesting that there must be a mechanism preventing ATMIN from disrupting ATM signaling in IR conditions. Here, we show that ATMIN is ubiquitinated by the E3 ligase UBR5, a modification that is stimulated by IR and favors its dissociation from ATM, freeing ATM to interact with NBS1. This mechanism allows efficient ATM activation at damage sites and promotes cell survival after irradiation..
Penicud, K.
Behrens, A.
(2014). DMAP1 is an essential regulator of ATM activity and function. Oncogene,
Vol.33
(4),
pp. 525-531.
Davies, C.C.
Chakraborty, A.
Diefenbacher, M.E.
Skehel, M.
Behrens, A.
(2013). Arginine methylation of the c-Jun coactivator RACO-1 is required for c-Jun/AP-1 activation. Embo j,
Vol.32
(11),
pp. 1556-1567.
show abstract
c-Jun, the major component of the AP-1 transcription factor complex, has important functions in cellular proliferation and oncogenic transformation. The RING domain-containing protein RACO-1 functions as a c-Jun coactivator that molecularly links growth factor signalling to AP-1 transactivation. Here we demonstrate that RACO-1 is present as a nuclear dimer and that c-Jun specifically interacts with dimeric RACO-1. Moreover, RACO-1 is identified as a substrate of the arginine methyltransferase PRMT1, which methylates RACO-1 on two arginine residues. Arginine methylation of RACO-1 promotes a conformational change that stabilises RACO-1 by facilitating K63-linked ubiquitin chain formation, and enables RACO-1 dimerisation and c-Jun interaction. Abrogation of PRMT1 function impairs AP-1 activity and results in decreased expression of a large percentage of c-Jun target genes. These results demonstrate that arginine methylation of RACO-1 is required for efficient transcriptional activation by c-Jun/AP-1 and thus identify PRMT1 as an important regulator of c-Jun/AP-1 function..
Sancho, R.
Blake, S.M.
Tendeng, C.
Clurman, B.E.
Lewis, J.
Behrens, A.
(2013). Fbw7 repression by hes5 creates a feedback loop that modulates Notch-mediated intestinal and neural stem cell fate decisions. Plos biol,
Vol.11
(6),
p. e1001586.
show abstract
FBW7 is a crucial component of an SCF-type E3 ubiquitin ligase, which mediates degradation of an array of different target proteins. The Fbw7 locus comprises three different isoforms, each with its own promoter and each suspected to have a distinct set of substrates. Most FBW7 targets have important functions in developmental processes and oncogenesis, including Notch proteins, which are functionally important substrates of SCF(Fbw7). Notch signalling controls a plethora of cell differentiation decisions in a wide range of species. A prominent role of this signalling pathway is that of mediating lateral inhibition, a process where exchange of signals that repress Notch ligand production amplifies initial differences in Notch activation levels between neighbouring cells, resulting in unequal cell differentiation decisions. Here we show that the downstream Notch signalling effector HES5 directly represses transcription of the E3 ligase Fbw7β, thereby directly bearing on the process of lateral inhibition. Fbw7(Δ/+) heterozygous mice showed haploinsufficiency for Notch degradation causing impaired intestinal progenitor cell and neural stem cell differentiation. Notably, concomitant inactivation of Hes5 rescued both phenotypes and restored normal stem cell differentiation potential. In silico modelling suggests that the NICD/HES5/FBW7β positive feedback loop underlies Fbw7 haploinsufficiency. Thus repression of Fbw7β transcription by Notch signalling is an essential mechanism that is coupled to and required for the correct specification of cell fates induced by lateral inhibition..
Fontana, X.
Hristova, M.
Da Costa, C.
Patodia, S.
Thei, L.
Makwana, M.
Spencer-Dene, B.
Latouche, M.
Mirsky, R.
Jessen, K.R.
Klein, R.
Raivich, G.
Behrens, A.
(2012). c-Jun in Schwann cells promotes axonal regeneration and motoneuron survival via paracrine signaling. Journal of cell biology,
Vol.198
(1),
pp. 127-141.
show abstract
The AP-1 transcription factor c-Jun is a master regulator of the axonal response in neurons. c-Jun also functions as a negative regulator of myelination in Schwann cells (SCs) and is strongly reactivated in SCs upon axonal injury. We demonstrate here that, after injury, the absence of c-Jun specifically in SCs caused impaired axonal regeneration and severely increased neuronal cell death. c-Jun deficiency resulted in decreased expression of several neurotrophic factors, and GDNF and Artemin, both of which encode ligands for the Ret receptor tyrosine kinase, were identified as novel direct c-Jun target genes. Genetic inactivation of Ret specifically in neurons resulted in regeneration defects without affecting motoneuron survival and, conversely, administration of recombinant GDNF and Artemin protein substantially ameliorated impaired regeneration caused by c-Jun deficiency. These results reveal an unexpected function for c-Jun in SCs in response to axonal injury, and identify paracrine Ret signaling as an important mediator of c-Jun function in SCs during regeneration..
Zhang, T.
Penicud, K.
Bruhn, C.
Loizou, J.I.
Kanu, N.
Wang, Z.-.
Behrens, A.
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Vol.2
(6),
pp. 1498-1504.
Aguilera, C.
Nakagawa, K.
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Behrens, A.
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Sancho, R.
Jandke, A.
Davis, H.
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Davies, C.C.
Chakraborty, A.
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Behrens, A.
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Vol.12
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pp. 963-972.
Hoeck, J.D.
Jandke, A.
Blake, S.M.
Nye, E.
Spencer-Dene, B.
Brandner, S.
Behrens, A.
(2010). Fbw7 controls neural stem cell differentiation and progenitor apoptosis via Notch and c-Jun. Nature neuroscience,
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Kanu, N.
Penicud, K.
Hristova, M.
Wong, B.
Irvine, E.
Plattner, F.
Raivich, G.
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pp. 38534-38542.