1
|
Fan Y, Chai C, Li P, Zou X, Ferrell JE, Wang B. Ultrafast distant wound response is essential for whole-body regeneration. Cell 2023; 186:3606-3618.e16. [PMID: 37480850 PMCID: PMC10957142 DOI: 10.1016/j.cell.2023.06.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 01/11/2023] [Accepted: 06/23/2023] [Indexed: 07/24/2023]
Abstract
Injury induces systemic responses, but their functions remain elusive. Mechanisms that can rapidly synchronize wound responses through long distances are also mostly unknown. Using planarian flatworms capable of whole-body regeneration, we report that injury induces extracellular signal-regulated kinase (Erk) activity waves to travel at a speed 10-100 times faster than those in other multicellular tissues. This ultrafast propagation requires longitudinal body-wall muscles, elongated cells forming dense parallel tracks running the length of the organism. The morphological properties of muscles allow them to act as superhighways for propagating and disseminating wound signals. Inhibiting Erk propagation prevents tissues distant to the wound from responding and blocks regeneration, which can be rescued by a second injury to distal tissues shortly after the first injury. Our findings provide a mechanism for long-range signal propagation in large, complex tissues to coordinate responses across cell types and highlight the function of feedback between spatially separated tissues during whole-body regeneration.
Collapse
Affiliation(s)
- Yuhang Fan
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Chew Chai
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Pengyang Li
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Xinzhi Zou
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
| |
Collapse
|
2
|
Mikhailov VF, Shulenina LV. Regulation of Gene Activity Is One of the Mechanisms for Changing Radiosensitivity. BIOL BULL+ 2022. [DOI: 10.1134/s1062359022110140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
|
3
|
Varlet P, Bouffet E, Casanova M, Giangaspero F, Antonelli M, Hargrave D, Ladenstein R, Pearson A, Hawkins C, König FB, Rüschoff J, Schmauch C, Bühnemann C, Garin-Chesa P, Schweifer N, Uttenreuther-Fischer M, Gibson N, Ittrich C, Krämer N, Solca F, Stolze B, Geoerger B. Comprehensive analysis of the ErbB receptor family in pediatric nervous system tumors and rhabdomyosarcoma. Pediatr Blood Cancer 2022; 69:e29316. [PMID: 34546642 DOI: 10.1002/pbc.29316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/05/2021] [Accepted: 08/01/2021] [Indexed: 11/11/2022]
Abstract
BACKGROUND There is a paucity of knowledge regarding pediatric biomarkers, including the relevance of ErbB pathway aberrations in pediatric tumors. We investigated the occurrence of ErbB receptor aberrations across different pediatric malignancies, to identify patterns of ErbB dysregulation and define biomarkers suitable for patient enrichment in clinical studies. PROCEDURE Tissue samples from 297 patients with nervous system tumors and rhabdomyosarcoma were analyzed for immunohistochemical expression or gene amplification of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2). Exploratory analyses of HER3/HER4 expression, and mRNA expression of ErbB receptors/ligands (NanoString) were performed. Assay validation followed general procedures, with additional validation to address Clinical Laboratory Improvement Amendments (CLIA) requirements. RESULTS In most tumor types, samples with high ErbB receptor expression were found with heterogeneous distribution. We considered increased/aberrant ErbB pathway activation when greater than or equal to two EGFR/HER2 markers were simultaneously upregulated. ErbB pathway dysregulation was identified in ∼20%-30% of samples for most tumor types (medulloblastoma/primitive neuroectodermal tumors 31.1%, high-grade glioma 27.1%, neuroblastoma 22.7%, rhabdomyosarcoma 23.1%, ependymoma 18.8%), 4.2% of diffuse intrinsic pontine gliomas, and no recurrent or refractory low-grade astrocytomas. In medulloblastoma/primitive neuroectodermal tumors and neuroblastoma, this was attributed mainly to high EGFR polysomy/HER2 amplification, whereas EGFR gene amplification was observed in some high-grade glioma samples. EGFR/HER2 overexpression was most prevalent in ependymoma. CONCLUSIONS Overexpression and/or amplification of EGFR/HER2 were identified as potential enrichment biomarkers for clinical trials of ErbB-targeted drugs.
Collapse
Affiliation(s)
- Pascale Varlet
- GHU Psychiatrie et Neurosciences, site Sainte-Anne, service de Neuropathologie, Paris, France
| | - Eric Bouffet
- The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | - Darren Hargrave
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ruth Ladenstein
- Department of Paediatrics, St. Anna Children's Cancer Research Institute, Medical University, Vienna, Austria
| | - Andy Pearson
- Paediatric Drug Development, Children and Young People's Unit, Royal Marsden Hospital, London, UK.,Division of Clinical Studies, Institute of Cancer Research, London, UK
| | | | | | | | | | | | - Pilar Garin-Chesa
- Staburo GmbH, Munich, Germany, on behalf of Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Norbert Schweifer
- Staburo GmbH, Munich, Germany, on behalf of Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | | | - Neil Gibson
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Carina Ittrich
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Nicole Krämer
- Staburo GmbH, Munich, Germany, on behalf of Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Flavio Solca
- Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria
| | - Britta Stolze
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Birgit Geoerger
- Gustave Roussy Cancer Center, Department of Pediatric and Adolescent Oncology, INSERM U1015, Université Paris Saclay, Villejuif, France
| |
Collapse
|
4
|
Ungefroren H. Autocrine TGF-β in Cancer: Review of the Literature and Caveats in Experimental Analysis. Int J Mol Sci 2021; 22:977. [PMID: 33478130 PMCID: PMC7835898 DOI: 10.3390/ijms22020977] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022] Open
Abstract
Autocrine signaling is defined as the production and secretion of an extracellular mediator by a cell followed by the binding of that mediator to receptors on the same cell to initiate signaling. Autocrine stimulation often operates in autocrine loops, a type of interaction, in which a cell produces a mediator, for which it has receptors, that upon activation promotes expression of the same mediator, allowing the cell to repeatedly autostimulate itself (positive feedback) or balance its expression via regulation of a second factor that provides negative feedback. Autocrine signaling loops with positive or negative feedback are an important feature in cancer, where they enable context-dependent cell signaling in the regulation of growth, survival, and cell motility. A growth factor that is intimately involved in tumor development and progression and often produced by the cancer cells in an autocrine manner is transforming growth factor-β (TGF-β). This review surveys the many observations of autocrine TGF-β signaling in tumor biology, including data from cell culture and animal models as well as from patients. We also provide the reader with a critical discussion on the various experimental approaches employed to identify and prove the involvement of autocrine TGF-β in a given cellular response.
Collapse
Affiliation(s)
- Hendrik Ungefroren
- First Department of Medicine, University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany;
- Clinic for General Surgery, Visceral, Thoracic, Transplantation and Pediatric Surgery, University Hospital Schleswig-Holstein, Campus Kiel, D-24105 Kiel, Germany
| |
Collapse
|
5
|
Bunker EN, Wheeler GE, Chapnick DA, Liu X. Suppression of α-catenin and adherens junctions enhances epithelial cell proliferation and motility via TACE-mediated TGF-α autocrine/paracrine signaling. Mol Biol Cell 2020; 32:348-361. [PMID: 33378218 PMCID: PMC8098817 DOI: 10.1091/mbc.e19-08-0474] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sustained cell migration is essential for wound healing and cancer metastasis. The epidermal growth factor receptor (EGFR) signaling cascade is known to drive cell migration and proliferation. While the signal transduction downstream of EGFR has been extensively investigated, our knowledge of the initiation and maintenance of EGFR signaling during cell migration remains limited. The metalloprotease TACE (tumor necrosis factor alpha converting enzyme) is responsible for producing active EGFR family ligands in the via ligand shedding. Sustained TACE activity may perpetuate EGFR signaling and reduce a cell’s reliance on exogenous growth factors. Using a cultured keratinocyte model system, we show that depletion of α-catenin perturbs adherens junctions, enhances cell proliferation and motility, and decreases dependence on exogenous growth factors. We show that the underlying mechanism for these observed phenotypical changes depends on enhanced autocrine/paracrine release of the EGFR ligand transforming growth factor alpha in a TACE-dependent manner. We demonstrate that proliferating keratinocyte epithelial cell clusters display waves of oscillatory extracellular signal–regulated kinase (ERK) activity, which can be eliminated by TACE knockout, suggesting that these waves of oscillatory ERK activity depend on autocrine/paracrine signals produced by TACE. These results provide new insights into the regulatory role of adherens junctions in initiating and maintaining autocrine/paracrine signaling with relevance to wound healing and cellular transformation.
Collapse
Affiliation(s)
- Eric N Bunker
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | - Graycen E Wheeler
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | | | - Xuedong Liu
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| |
Collapse
|
6
|
Son J, Du Y. Comparison of intrusive and nonintrusive polynomial chaos expansion-based approaches for high dimensional parametric uncertainty quantification and propagation. Comput Chem Eng 2020. [DOI: 10.1016/j.compchemeng.2019.106685] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
7
|
Dent P, Booth L, Poklepovic A, Hancock JF. Signaling alterations caused by drugs and autophagy. Cell Signal 2019; 64:109416. [PMID: 31520735 DOI: 10.1016/j.cellsig.2019.109416] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022]
Abstract
Autophagy is an evolutionary conserved process that recycles cellular materials in times of nutrient restriction to maintain viability. In cancer therapeutics, the role of autophagy in response to multi-kinase inhibitors, alone or when combined with histone deacetylase (HDAC) inhibitors acts, generally, to facilitate the killing of tumor cells. Furthermore, the formation of autophagosomes and subsequent degradation of their contents can reduce the expression of HDAC proteins themselves as well as of other signaling regulatory molecules such as protein chaperones and mutated RAS proteins. Reduced levels of HDAC6 causes the acetylation and inactivation of heat shock protein 90, and, together with reduced expression of the chaperones HSP70 and GRP78, generates a strong endoplasmic reticulum (ER) stress response. Prolonged intense ER stress signaling causes tumor cell death. Reduced expression of HDACs 1, 2 and 3 causes the levels of programed death ligand 1 (PD-L1) to decline and the expression of Class I MHCA to increase which correlates with elevated immunogenicity of the tumor cells in vivo. This review will specifically focus on the downstream implications that result from autophagic-degradation of HDACs, RAS and protein chaperones.
Collapse
Affiliation(s)
- Paul Dent
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
| | - Laurence Booth
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Andrew Poklepovic
- Department of Biochemistry and Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
| |
Collapse
|
8
|
Dey A, Barik D. Dichotomous Nature of Bistability Generated by Negative Cooperativity in Receptor-Ligand Binding. ACS Synth Biol 2019; 8:1294-1302. [PMID: 31132851 DOI: 10.1021/acssynbio.8b00517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Positive cooperativity in receptor-ligand binding plays an important role in cell signaling as it generates an ultrasensitive response, a requirement for nonlinear phenomena such as bistability and oscillations in feedback regulated reaction networks. On the other hand, negative cooperativity typically produces a hyperbolic response and is thus less explored. However, recently negative cooperativity was shown to generate an ultrasensitive response under the condition of strong ligand affinity. In this work, we have used mathematical modeling to investigate the effect of negative cooperativity in receptor-ligand interaction on the bistability in a positive feedback regulatory motif. We systematically investigated the effect of negative cooperativity, modifying the two equilibrium constants of the receptor-ligand binding, on the robustness and tunability of bistability. We show that in the regime where negative cooperativity exhibits robust bistability, positive cooperativity results in poor bistability and vice versa. Further we find that the robustness and tunability of bistability depend crucially on the stability of singly and doubly engaged receptors. Our modeling highlights the ability of negative cooperativity to produce complex phenomena with potential applications in designing synthetic devices or in explaining experimental observations in cell biology.
Collapse
Affiliation(s)
- Anupam Dey
- School of Chemistry, University of Hyderabad, Central University
P.O., Hyderabad, 500046 Telangana, India
| | - Debashis Barik
- School of Chemistry, University of Hyderabad, Central University
P.O., Hyderabad, 500046 Telangana, India
| |
Collapse
|
9
|
Pouget JP, Georgakilas AG, Ravanat JL. Targeted and Off-Target (Bystander and Abscopal) Effects of Radiation Therapy: Redox Mechanisms and Risk/Benefit Analysis. Antioxid Redox Signal 2018; 29:1447-1487. [PMID: 29350049 PMCID: PMC6199630 DOI: 10.1089/ars.2017.7267] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Radiation therapy (from external beams to unsealed and sealed radionuclide sources) takes advantage of the detrimental effects of the clustered production of radicals and reactive oxygen species (ROS). Research has mainly focused on the interaction of radiation with water, which is the major constituent of living beings, and with nuclear DNA, which contains the genetic information. This led to the so-called target theory according to which cells have to be hit by ionizing particles to elicit an important biological response, including cell death. In cancer therapy, the Poisson law and linear quadratic mathematical models have been used to describe the probability of hits per cell as a function of the radiation dose. Recent Advances: However, in the last 20 years, many studies have shown that radiation generates "danger" signals that propagate from irradiated to nonirradiated cells, leading to bystander and other off-target effects. CRITICAL ISSUES Like for targeted effects, redox mechanisms play a key role also in off-target effects through transmission of ROS and reactive nitrogen species (RNS), and also of cytokines, ATP, and extracellular DNA. Particularly, nuclear factor kappa B is essential for triggering self-sustained production of ROS and RNS, thus making the bystander response similar to inflammation. In some therapeutic cases, this phenomenon is associated with recruitment of immune cells that are involved in distant irradiation effects (called "away-from-target" i.e., abscopal effects). FUTURE DIRECTIONS Determining the contribution of targeted and off-target effects in the clinic is still challenging. This has important consequences not only in radiotherapy but also possibly in diagnostic procedures and in radiation protection.
Collapse
Affiliation(s)
- Jean-Pierre Pouget
- 1 Institut de Recherche en Cancérologie de Montpellier (IRCM) , INSERM, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, France
| | - Alexandros G Georgakilas
- 2 DNA Damage Laboratory, Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens , Athens, Greece
| | - Jean-Luc Ravanat
- 3 Univ. Grenoble Alpes , CEA, CNRS INAC SyMMES UMR 5819, Grenoble, France
| |
Collapse
|
10
|
Epidermal growth factor receptor (EGFR): A rising star in the era of precision medicine of lung cancer. Oncotarget 2018; 8:50209-50220. [PMID: 28430586 PMCID: PMC5564844 DOI: 10.18632/oncotarget.16854] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/24/2017] [Indexed: 12/30/2022] Open
Abstract
Lung cancer is a leading cause of cancer mortality worldwide. In tumors, the important role of noncoding RNA regulatory networks has been more and more reveal. EGFR has been identified as an oncogenic driver of NSCLC, especially activating mutations EGFR and its inhibition with specific TKIs can generate dramatic tumor responses. Studies have shown that EGFR plays significant roles in the progression of NSCLC. Subset analysis of the small proportion of patients with EGFR-mutant lung cancer showed a disease-free survival benefit, but was underpowered to detect a survival advantage. Herein, we highlight the progression of EGFR, noncoding RNA, and their roles in carcinogenesis. We also focus on anti-lung cancer drug development and EGFR-related drug resistance.
Collapse
|
11
|
Přibyl M, Schreiber I. Traveling-wave Phenomena in a Model of Autocrine Signaling Coupled with Dynamics of the MAPK Cascade. Isr J Chem 2017. [DOI: 10.1002/ijch.201700117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michal Přibyl
- University of Chemistry and Technology; Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Igor Schreiber
- University of Chemistry and Technology; Prague Technická 5 166 28 Prague 6 Czech Republic
| |
Collapse
|
12
|
Komova O, Krasavin E, Nasonova E, Mel’nikova L, Shmakova N, Cunha M, Testa E, Beuve M. Relationship between radioadaptive response and individual radiosensitivity to low doses of gamma radiation: an extended study of chromosome damage in blood lymphocytes of three donors. Int J Radiat Biol 2017; 94:54-61. [DOI: 10.1080/09553002.2018.1399226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Olga Komova
- Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research (JINR), Dubna, Russia
| | - Eugene Krasavin
- Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research (JINR), Dubna, Russia
| | - Elena Nasonova
- Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research (JINR), Dubna, Russia
| | - Larisa Mel’nikova
- Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research (JINR), Dubna, Russia
| | - Nina Shmakova
- Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research (JINR), Dubna, Russia
| | - Micaela Cunha
- Department of Radiation Sciences, Université de Lyon, Lyon, France
- Department of Radiation Sciences, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
| | - Etienne Testa
- Department of Radiation Sciences, Université de Lyon, Lyon, France
- Department of Radiation Sciences, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
| | - Michaël Beuve
- Department of Radiation Sciences, Université de Lyon, Lyon, France
- Department of Radiation Sciences, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
| |
Collapse
|
13
|
Doğaner BA, Yan LK, Youk H. Autocrine Signaling and Quorum Sensing: Extreme Ends of a Common Spectrum. Trends Cell Biol 2016; 26:262-271. [DOI: 10.1016/j.tcb.2015.11.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 11/30/2022]
|
14
|
Sparta B, Pargett M, Minguet M, Distor K, Bell G, Albeck JG. Receptor Level Mechanisms Are Required for Epidermal Growth Factor (EGF)-stimulated Extracellular Signal-regulated Kinase (ERK) Activity Pulses. J Biol Chem 2015; 290:24784-92. [PMID: 26304118 DOI: 10.1074/jbc.m115.662247] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Indexed: 11/06/2022] Open
Abstract
In both physiological and cell culture systems, EGF-stimulated ERK activity occurs in discrete pulses within individual cells. Many feedback loops are present in the EGF receptor (EGFR)-ERK network, but the mechanisms driving pulsatile ERK kinetics are unknown. Here, we find that in cells that respond to EGF with frequency-modulated pulsatile ERK activity, stimulation through a heterologous TrkA receptor system results in non-pulsatile, amplitude-modulated activation of ERK. We further dissect the kinetics of pulse activity using a combination of FRET- and translocation-based reporters and find that EGFR activity is required to maintain ERK activity throughout the 10-20-minute lifetime of pulses. Together, these data indicate that feedbacks operating within the core Ras-Raf-MEK-ERK cascade are insufficient to drive discrete pulses of ERK activity and instead implicate mechanisms acting at the level of EGFR.
Collapse
Affiliation(s)
- Breanne Sparta
- From the Departments of Molecular and Cellular Biology and
| | | | - Marta Minguet
- From the Departments of Molecular and Cellular Biology and
| | - Kevin Distor
- From the Departments of Molecular and Cellular Biology and
| | - George Bell
- Microbiology and Molecular Genetics, University of California, Davis, California 95616
| | - John G Albeck
- From the Departments of Molecular and Cellular Biology and
| |
Collapse
|
15
|
Stimulus-dependent differences in signalling regulate epithelial-mesenchymal plasticity and change the effects of drugs in breast cancer cell lines. Cell Commun Signal 2015; 13:26. [PMID: 25975820 PMCID: PMC4432969 DOI: 10.1186/s12964-015-0106-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 04/22/2015] [Indexed: 12/18/2022] Open
Abstract
Introduction The normal process of epithelial mesenchymal transition (EMT) is subverted by carcinoma cells to facilitate metastatic spread. Cancer cells rarely undergo a full conversion to the mesenchymal phenotype, and instead adopt positions along the epithelial-mesenchymal axis, a propensity we refer to as epithelial mesenchymal plasticity (EMP). EMP is associated with increased risk of metastasis in breast cancer and consequent poor prognosis. Drivers towards the mesenchymal state in malignant cells include growth factor stimulation or exposure to hypoxic conditions. Methods We have examined EMP in two cell line models of breast cancer: the PMC42 system (PMC42-ET and PMC42-LA sublines) and MDA-MB-468 cells. Transition to a mesenchymal phenotype was induced across all three cell lines using epidermal growth factor (EGF) stimulation, and in MDA-MB-468 cells by hypoxia. We used RNA sequencing to identify gene expression changes that occur as cells transition to a more-mesenchymal phenotype, and identified the cell signalling pathways regulated across these experimental systems. We then used inhibitors to modulate signalling through these pathways, verifying the conclusions of our transcriptomic analysis. Results We found that EGF and hypoxia both drive MDA-MB-468 cells to phenotypically similar mesenchymal states. Comparing the transcriptional response to EGF and hypoxia, we have identified differences in the cellular signalling pathways that mediate, and are influenced by, EMT. Significant differences were observed for a number of important cellular signalling components previously implicated in EMT, such as HBEGF and VEGFA. We have shown that EGF- and hypoxia-induced transitions respond differently to treatment with chemical inhibitors (presented individually and in combinations) in these breast cancer cells. Unexpectedly, MDA-MB-468 cells grown under hypoxic growth conditions became even more mesenchymal following exposure to certain kinase inhibitors that prevent growth-factor induced EMT, including the mTOR inhibitor everolimus and the AKT1/2/3 inhibitor AZD5363. Conclusions While resulting in a common phenotype, EGF and hypoxia induced subtly different signalling systems in breast cancer cells. Our findings have important implications for the use of kinase inhibitor-based therapeutic interventions in breast cancers, where these heterogeneous signalling landscapes will influence the therapeutic response. Electronic supplementary material The online version of this article (doi:10.1186/s12964-015-0106-x) contains supplementary material, which is available to authorized users.
Collapse
|
16
|
Serum amyloid A and inflammation in diabetic kidney disease and podocytes. J Transl Med 2015; 95:250-62. [PMID: 25531567 PMCID: PMC4346621 DOI: 10.1038/labinvest.2014.163] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/04/2014] [Accepted: 11/24/2014] [Indexed: 12/27/2022] Open
Abstract
Inflammatory pathways are central mechanisms in diabetic kidney disease (DKD). Serum amyloid A (SAA) is increased by chronic inflammation, but SAA has not been previously evaluated as a potential DKD mediator. The aims of this study were to determine whether SAA is increased in human DKD and corresponding mouse models and to assess effects of SAA on podocyte inflammatory responses. SAA was increased in the plasma of people with DKD characterized by overt proteinuria and inversely correlated with estimated glomerular filtration rate (creatinine-based CKD-EPI). SAA was also elevated in plasma of diabetic mouse models including type 1 diabetes (streptozotocin/C57BL/6) and type 2 diabetes (BTBR-ob/ob). SAA mRNA (Nephromine) was increased in human DKD compared with non-diabetic and/or glomerular disease controls (glomerular fold change 1.5, P=0.017; tubulointerstitium fold change 1.4, P=0.021). The kidneys of both diabetic mouse models also demonstrated increased SAA mRNA (quantitative real-time PCR) expression compared with non-diabetic controls (type 1 diabetes fold change 2.9; type 2 diabetes fold change 42.5, P=0.009; interaction by model P=0.57). Humans with DKD and the diabetic mouse models exhibited extensive SAA protein deposition in the glomeruli and tubulointerstitium in similar patterns by immunohistochemistry. SAA localized within podocytes of diabetic mice. Podocytes exposed to advanced glycation end products, metabolic mediators of inflammation in diabetes, increased expression of SAA mRNA (fold change 15.3, P=0.004) and protein (fold change 38.4, P=0.014). Podocytes exposed to exogenous SAA increased NF-κB activity, and pathway array analysis revealed upregulation of mRNA for NF-κB-dependent targets comprising numerous inflammatory mediators, including SAA itself (fold change 17.0, P=0.006). Inhibition of NF-κB reduced these pro-inflammatory responses. In conclusion, SAA is increased in the blood and produced in the kidneys of people with DKD and corresponding diabetic mouse models. Podocytes are likely to be key responder cells to SAA-induced inflammation in the diabetic kidney. SAA is a compelling candidate for DKD therapeutic and biomarker discovery.
Collapse
|
17
|
Youk H, Lim WA. Secreting and sensing the same molecule allows cells to achieve versatile social behaviors. Science 2014; 343:1242782. [PMID: 24503857 PMCID: PMC4145839 DOI: 10.1126/science.1242782] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cells that secrete and sense the same signaling molecule are ubiquitous. To uncover the functional capabilities of the core "secrete-and-sense" circuit motif shared by these cells, we engineered yeast to secrete and sense the mating pheromone. Perturbing each circuit element revealed parameters that control the degree to which the cell communicated with itself versus with its neighbors. This tunable interplay of self-communication and neighbor communication enables cells to span a diverse repertoire of cellular behaviors. These include a cell being asocial by responding only to itself and social through quorum sensing, and an isogenic population of cells splitting into social and asocial subpopulations. A mathematical model explained these behaviors. The versatility of the secrete-and-sense circuit motif may explain its recurrence across species.
Collapse
Affiliation(s)
- Hyun Youk
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
- Center for Systems and Synthetic Biology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Wendell A. Lim
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
- Center for Systems and Synthetic Biology, University of California San Francisco, San Francisco, CA 94158, USA
- Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA 94158, USA
| |
Collapse
|
18
|
Rutter GA, Hodson DJ. Minireview: intraislet regulation of insulin secretion in humans. Mol Endocrinol 2013; 27:1984-95. [PMID: 24243488 PMCID: PMC5426601 DOI: 10.1210/me.2013-1278] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/23/2013] [Indexed: 12/25/2022] Open
Abstract
The higher organization of β-cells into spheroid structures termed islets of Langerhans is critical for the proper regulation of insulin secretion. Thus, rodent β-cells form a functional syncytium that integrates and propagates information encoded by secretagogues, producing a "gain-of-function" in hormone release through the generation of coordinated cell-cell activity. By contrast, human islets possess divergent topology, and this may have repercussions for the cell-cell communication pathways that mediate the population dynamics underlying the intraislet regulation of insulin secretion. This is pertinent for type 2 diabetes mellitus pathogenesis, and its study in rodent models, because environmental and genetic factors may converge on these processes in a species-specific manner to precipitate the defective insulin secretion associated with glucose intolerance. The aim of the present minireview is therefore to discuss the structural and functional underpinnings that influence insulin secretion from human islets, and the possibility that dyscoordination between individual β-cells may play an important role in some forms of type 2 diabetes mellitus.
Collapse
Affiliation(s)
- Guy A Rutter
- Section Cell Biology, Department of Medicine, Imperial College London, London SW7 2AZ, United Kingdom. ; or Professor Guy A. Rutter, Section of Cell Biology, Department of Medicine, Imperial College London, London SW7 2AZ, United Kingdom. E-mail:
| | | |
Collapse
|
19
|
Abstract
Physical forces are central players in development and morphogenesis, provide an ever-present backdrop influencing physiological functions, and contribute to a variety of pathologies. Mechanotransduction encompasses the rich variety of ways in which cells and tissues convert cues from their physical environment into biochemical signals. These cues include tensile, compressive and shear stresses, and the stiffness or elastic modulus of the tissues in which cells reside. This article focuses on the proximal events that lead directly from a change in physical state to a change in cell-signaling state. A large body of evidence demonstrates a prominent role for the extracellular matrix, the intracellular cytoskeleton, and the cell matrix adhesions that link these networks in transduction of the mechanical environment. Recent work emphasizes the important role of physical unfolding or conformational changes in proteins induced by mechanical loading, with examples identified both within the focal adhesion complex at the cell-matrix interface and in extracellular matrix proteins themselves. Beyond these adhesion and matrix-based mechanisms, classical and new mechanisms of mechanotransduction reside in stretch-activated ion channels, the coupling of physical forces to interstitial autocrine and paracrine signaling, force-induced activation of extracellular proteins, and physical effects directly transmitted to the cell's nucleus. Rapid progress is leading to detailed delineation of molecular mechanisms by which the physical environment shapes cellular signaling events, opening up avenues for exploring how mechanotransduction pathways are integrated into physiological and pathophysiological cellular and tissue processes.
Collapse
Affiliation(s)
- Daniel J Tschumperlin
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
| |
Collapse
|
20
|
Janes KA, Lauffenburger DA. Models of signalling networks - what cell biologists can gain from them and give to them. J Cell Sci 2013; 126:1913-21. [PMID: 23720376 DOI: 10.1242/jcs.112045] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Computational models of cell signalling are perceived by many biologists to be prohibitively complicated. Why do math when you can simply do another experiment? Here, we explain how conceptual models, which have been formulated mathematically, have provided insights that directly advance experimental cell biology. In the past several years, models have influenced the way we talk about signalling networks, how we monitor them, and what we conclude when we perturb them. These insights required wet-lab experiments but would not have arisen without explicit computational modelling and quantitative analysis. Today, the best modellers are cross-trained investigators in experimental biology who work closely with collaborators but also undertake experimental work in their own laboratories. Biologists would benefit by becoming conversant in core principles of modelling in order to identify when a computational model could be a useful complement to their experiments. Although the mathematical foundations of a model are useful to appreciate its strengths and weaknesses, they are not required to test or generate a worthwhile biological hypothesis computationally.
Collapse
Affiliation(s)
- Kevin A Janes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | | |
Collapse
|
21
|
Gong W, Wang ZY, Chen GX, Liu YQ, Gu XY, Liu WW. Invasion potential of H22 hepatocarcinoma cells is increased by HMGB1-induced tumor NF-κB signaling via initiation of HSP70. Oncol Rep 2013; 30:1249-56. [PMID: 23836405 DOI: 10.3892/or.2013.2595] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 06/03/2013] [Indexed: 12/22/2022] Open
Abstract
The functional relationship and cross-regulation between damage-associated molecular patterns and NF‑κB in the tumor microenvironment remains unclear. In the present study, high-mobility group protein B1 (HMGB1) was secreted in response to feed second phase of NF‑κB activation from heat shock protein (HSP) 70 that may result in a higher invasion potential of hepatocarcinoma cells. HSP70 promoted the proliferation of H22 hepatocarcinoma cells through Toll-like receptor (TLR) 2 and TLR4 signaling and induced the early phosphorylation of NF-κB, which reached maximum levels within 30 min. However, HSP70 promoted the upregulation of Beclin-1 expression via Jun N-terminal kinase (JNK) activation in tumor cells and the release of HMGB1 from tumor cells. Inhibition of Beclin-1/c-JNK production prevented the second, but not the first, phase of NF-κB phosphorylation, implicating Beclin-1/c-JNK in the second phase of phosphorylation. HSP70 induced Beclin-1-derived HMGB1 production at 4 h, which occurred before the rise in the second phosphorylation that occurred at 6 h. Exogenous HMGB1 also induced the rapid phosphorylation of NF-κB and upregulated the expression of MMP-9, inhibited the rapid phosphorylation of NF-κB and reduced MMP-9 by receptor for advanced glycation end products (RAGE) inhibitor that prevented HMGB1-induced cell invasion in vitro, which demonstrated that the biological significance of HMGB1/RAGE is key to the second, but not the first, phase of NF-κB phosphorylation in tumor cells. HSP70 triggered a positive feedback loop of NF-κB activation in H22 cells. The second phase of NF-κB phosphorylation mediated by HSP70 is implicated in the increase of tumor cell malignant invasion.
Collapse
Affiliation(s)
- Wei Gong
- Department of Oncology, XiangYang Central Hospital, Hubei University of Arts and Science, XiangYang, Hubei 441021, P.R. China
| | | | | | | | | | | |
Collapse
|
22
|
Simakov DSA, Pismen LM. Discrete model of periodic pattern formation through a combined autocrine–juxtacrine cell signaling. Phys Biol 2013; 10:046001. [DOI: 10.1088/1478-3975/10/4/046001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
23
|
Abstract
The central dogma of molecular biology has come under scrutiny in recent years. Here, we reviewed high-throughput mRNA and protein expression data of Escherichia coli, Saccharomyces cerevisiae, and several mammalian cells. At both single cell and population scales, the statistical comparisons between the entire transcriptomes and proteomes show clear correlation structures. In contrast, the pair-wise correlations of single transcripts to proteins show nullity. These data suggest that the organizing structure guiding cellular processes is observed at omics-wide scale, and not at single molecule level. The central dogma, thus, globally emerges as an average integrated flow of cellular information.
Collapse
Affiliation(s)
- Vincent Piras
- Institute for Advanced Biosciences, Keio University Tsuruoka, Yamagata, Japan ; Graduate School of Media and Governance, Keio University Fujisawa, Kanagawa, Japan
| | | | | |
Collapse
|
24
|
Shankarraman V, Davis-Gorman G, McDonagh PF, Caplan MR. Intracellular signaling controls endothelial cell prostacyclin secretion and regulation of blood clotting time. J Biomed Mater Res A 2012; 100:3374-83. [PMID: 22767493 DOI: 10.1002/jbm.a.34266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 04/05/2012] [Accepted: 05/03/2012] [Indexed: 11/11/2022]
Abstract
Blood is constantly in contact with a biological material, the blood vessel wall, without the need for anticoagulants to prevent clot formation on the vessel wall; however, man-made biomaterials require anticoagulants to prevent clot formation on the biomaterial. This study seeks to understand how some biomaterials elicit anticoagulant responses from endothelial cells (ECs), whereas others do not. Partial least squares regression analysis was used to correlate the activity of four relevant signaling molecules [extracellular signal-related kinase (ERK), c-Jun N-terminal kinase (JNK), Akt, and IκB kinase (IKK)] with human umbilical vein EC secretion of prostacyclin and clotting time of whole blood in contact with these cells. Prostacyclin secretion was increased when JNK activity (mean of all time-points) was elevated and IKK activity at 30 min was reduced. In addition, the clotting time, R-time measured by thromboelastography, was increased (reduced coagulability) when activity of both ERK and JNK (mean of all time-points) were increased and when Akt activity was increased at longer contact times (24-72 h after cell contact with material). Inhibition of each signaling molecule with subsequent testing for prostacyclin secretion and R-time confirmed the interrelationship between EC intracellular signaling and prostacyclin secretion. Generally, JNK inhibition decreased and IKK inhibition increased prostacyclin secretion. Inhibition of ERK or JNK generally increased coagulability, and Akt inhibition decreased the R-time of samples normally eliciting reduced coagulability. These findings increase our understanding of the signaling pathways involved in endothelial prostacyclin release and suggest targets for developing EC-seeded biomaterial surfaces that can minimize coagulation.
Collapse
Affiliation(s)
- Venkat Shankarraman
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | | | | | | |
Collapse
|
25
|
Effects of convective transport on chemical signal propagation in epithelia. Biophys J 2012; 102:990-1000. [PMID: 22404921 DOI: 10.1016/j.bpj.2012.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/13/2012] [Accepted: 01/23/2012] [Indexed: 11/20/2022] Open
Abstract
We study effects of convective transport on a chemical front wave representing a signal propagation at a simple (single layer) epithelium by means of mathematical modeling. Plug flow and laminar flow regimes were considered. We observed a nonmonotonous dependence of the propagation velocity on the ligand receptor binding constant under influence of the convective transport. If the signal propagates downstream, the region of high velocities becomes much broader and spreads over several orders of magnitude of the binding constant. When the convective transport is oriented against the propagating signal, either velocity of the traveling front wave is slowed down or the traveling front wave can stop or reverse the direction of propagation. More importantly, chemical signal in epithelial systems influenced by the convective transport can propagate almost independently of the ligand-receptor binding constant in a broad range of this parameter. Furthermore, we found that the effects of the convective transport becomes more significant in systems where either the characteristic dimension of the extracellular space is larger/comparable with the spatial extent of the ligand diffusion trafficking or the ligand-receptor binding/ligand diffusion rate ratio is high.
Collapse
|
26
|
Arlt A, Müerköster SS, Schäfer H. Targeting apoptosis pathways in pancreatic cancer. Cancer Lett 2010; 332:346-58. [PMID: 21078544 DOI: 10.1016/j.canlet.2010.10.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 10/06/2010] [Accepted: 10/20/2010] [Indexed: 01/07/2023]
Abstract
Pancreatic cancer - here in particular pancreatic ductal adenocarcinoma (PDAC) - is still a highly therapy refractory disease. Amongst the mechanisms by which PDAC cells could escape any non-surgical therapy, anti-apoptotic protection seems to be the most relevant one. PDAC cells have acquired resistance to apoptotic stimuli such as death ligands (FasL, TRAIL) or anti-cancer drugs (gemcitabine) by a great number of molecular alterations either disrupting an apoptosis inducing signal or counteracting the execution of apoptosis. Thus, PDAC cells exhibit alterations in the EGFR/MAPK/Ras/raf1-, PI3K/Akt-, TRAIL/TRAF2-, or IKK/NF-κB pathway accompanied by deregulations in the expression of apoptosis regulators such as cIAP, Bcl2, XIAP or survivin. Along with protection against apoptosis, PDAC cells also overexpress histone deacetylases (HDACs) giving rise to epigenetic patterns of chemoresistance and to acetylation of other regulatory proteins, as well. With respect to the multitude of anti-apoptotic pathways, a great number of molecular targets might be of high potential in novel therapy strategies. Thus, natural compounds as well as novel synthetic drugs are considered to be used in single or combined therapy of PDAC. A number of proteasome and HDAC inhibitors or selective inhibitors of IKK, EGFR, Akt and mTOR have been widely explored in preclinical settings and clinical studies. Even though these early studies encouraged an application in a clinical setting, most of the trials have been rather disappointing yet. Thus, new molecular targets and novel concepts of combination therapies need to get access into clinical trials - either in neoadjuvant/adjuvant or in palliative treatments.
Collapse
Affiliation(s)
- Alexander Arlt
- Laboratory of Molecular Gastroenterology and Hepatology, Dept. of Internal Medicine 1, UKSH-Campus Kiel, Schittenhelmstr. 12, 24105 Kiel, Germany
| | | | | |
Collapse
|
27
|
Mariotti L, Facoetti A, Alloni D, Bertolotti A, Ranza E, Ottolenghi A. Effects of ionizing radiation on cell-to-cell communication. Radiat Res 2010; 174:280-9. [PMID: 20726722 DOI: 10.1667/rr1889.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cell-to-cell signaling has become a significant issue in radiation biology due to experimental evidence, accumulated primarily since the early 1990s, of radiation-induced bystander effects. Several candidate mediators involved in cell-to-cell communication have been investigated and proposed as being responsible for this phenomenon, but the current investigation techniques (both theoretical and experimental) of the mechanisms involved, due to the particular set-up of each experiment, result in experimental data that often are not directly comparable. In this study, a comprehensive approach was adopted to describe cell-to-cell communication (focusing on cytokine signaling) and its modulation by external agents such as ionizing radiation. The aim was also to provide integrated theoretical instruments and experimental data to help in understanding the peculiarities of in vitro experiments. Theoretical/modeling activities were integrated with experimental measurements by (1) redesigning a cybernetic model (proposed in its original form in the 1950s) to frame cell-to-cell communication processes, (2) implementing and developing a mathematical model, and (3) designing and carrying out experiments to quantify key parameters involved in intercellular signaling (focusing as a pilot study on the release and decay of IL-6 molecules and their modulation by radiation). This formalization provides an interpretative framework for understanding the intercellular signaling and in particular for focusing on the study of cell-to-cell communication in a "step-by-step" approach. Under this model, the complex phenomenon of signal transmission was reduced where possible into independent processes to investigate them separately, providing an evaluation of the role of cell communication to guarantee and maintain the robustness of the in vitro experimental systems against the effects of perturbations.
Collapse
Affiliation(s)
- Luca Mariotti
- Dipartimento di Fisica Nucleare e Teorica, Università degli Studi di Pavia, 27100 Pavia, Italy.
| | | | | | | | | | | |
Collapse
|
28
|
Joslin EJ, Shankaran H, Opresko LK, Bollinger N, Lauffenburger DA, Wiley HS. Structure of the EGF receptor transactivation circuit integrates multiple signals with cell context. MOLECULAR BIOSYSTEMS 2010; 6:1293-306. [PMID: 20458382 PMCID: PMC3306786 DOI: 10.1039/c003921g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Transactivation of the epidermal growth factor receptor (EGFR) is thought to be a process by which a variety of cellular inputs can be integrated into a single signaling pathway through either stimulated proteolysis (shedding) of membrane-anchored EGFR ligands or by modification of the activity of the EGFR. As a first step towards building a predictive model of the EGFR transactivation circuit, we quantitatively defined how signals from multiple agonists were integrated both upstream and downstream of the EGFR to regulate extracellular signal regulated kinase (ERK) activity in human mammary epithelial cells. By using a "non-binding" reporter of ligand shedding, we found that transactivation triggers a positive feedback loop from ERK back to the EGFR such that ligand shedding drives EGFR-stimulated ERK that in turn drives further ligand shedding. Importantly, activated Ras and ERK levels were nearly linear functions of ligand shedding and the effect of multiple, sub-saturating inputs was additive. Simulations showed that ERK-mediated feedback through ligand shedding resulted in a stable steady-state level of activated ERK, but also showed that the extracellular environment can modulate the level of feedback. Our results suggest that the transactivation circuit acts as a context-dependent integrator and amplifier of multiple extracellular signals and that signal integration can effectively occur at multiple points in the EGFR pathway.
Collapse
Affiliation(s)
- Elizabeth J. Joslin
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139
| | - Harish Shankaran
- Systems Biology Program, Pacific Northwest National Laboratory, Richland, WA 99354
| | - Lee K. Opresko
- Systems Biology Program, Pacific Northwest National Laboratory, Richland, WA 99354
| | - Nikki Bollinger
- Systems Biology Program, Pacific Northwest National Laboratory, Richland, WA 99354
| | - Douglas A. Lauffenburger
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139
| | - H. Steven Wiley
- Systems Biology Program, Pacific Northwest National Laboratory, Richland, WA 99354
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354
| |
Collapse
|
29
|
Qiao L, Phipps-Yonas H, Hartmann B, Moran TM, Sealfon SC, Hayot F. Immune response modeling of interferon beta-pretreated influenza virus-infected human dendritic cells. Biophys J 2010; 98:505-14. [PMID: 20159146 DOI: 10.1016/j.bpj.2009.10.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 09/18/2009] [Accepted: 10/30/2009] [Indexed: 12/20/2022] Open
Abstract
The pretreatment of human dendritic cells with interferon-beta enhances their immune response to influenza virus infection. We measured the expression levels of several key players in that response over a period of 13 h both during pretreatment and after viral infection. Their activation profiles reflect the presence of both negative and positive feedback loops in interferon induction and interferon signaling pathway. Based on these measurements, we have developed a comprehensive computational model of cellular immune response that elucidates its mechanism and its dynamics in interferon-pretreated dendritic cells, and provides insights into the effects of duration and strength of pretreatment.
Collapse
Affiliation(s)
- Liang Qiao
- Department of Neurology, Mount Sinai School of Medicine, New York, New York, USA
| | | | | | | | | | | |
Collapse
|
30
|
ATP-gated P2X3 receptors constitute a positive autocrine signal for insulin release in the human pancreatic beta cell. Proc Natl Acad Sci U S A 2010; 107:6465-70. [PMID: 20308565 DOI: 10.1073/pnas.0908935107] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Extracellular ATP has been proposed as a paracrine signal in rodent islets, but it is unclear what role ATP plays in human islets. We now show the presence of an ATP signaling pathway that enhances the human beta cell's sensitivity and responsiveness to glucose fluctuations. By using in situ hybridization, RT-PCR, immunohistochemistry, and Western blotting as well as recordings of cytoplasmic-free Ca(2+) concentration, [Ca(2+)](i), and hormone release in vitro, we show that human beta cells express ionotropic ATP receptors of the P2X(3) type and that activation of these receptors by ATP coreleased with insulin amplifies glucose-induced insulin secretion. Released ATP activates P2X(3) receptors in the beta-cell plasma membrane, resulting in increased [Ca(2+)](i) and enhanced insulin secretion. Therefore, in human islets, released ATP forms a positive autocrine feedback loop that sensitizes the beta cell's secretory machinery. This may explain how the human pancreatic beta cell can respond so effectively to relatively modest changes in glucose concentration under physiological conditions in vivo.
Collapse
|
31
|
|
32
|
Iwasa T, Okamoto I, Suzuki M, Hatashita E, Yamada Y, Fukuoka M, Ono K, Nakagawa K. Inhibition of insulin-like growth factor 1 receptor by CP-751,871 radiosensitizes non-small cell lung cancer cells. Clin Cancer Res 2009; 15:5117-25. [PMID: 19671857 DOI: 10.1158/1078-0432.ccr-09-0478] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Therapeutic strategies that target the insulin-like growth factor I receptor (IGF-1R) hold promise for a wide variety of cancers. We have now investigated the effect of CP-751,871, a fully human monoclonal antibody specific for IGF-IR, on the sensitivity of human non-small cell lung cancer (NSCLC) cell lines to radiation. EXPERIMENTAL DESIGN The radiosensitizing effect of CP-751,871 was evaluated on the basis of cell death, clonogenic survival, and progression of tumor xenografts. Radiation-induced damage was evaluated by immunofluorescence analysis of the histone gamma-H2AX and Rad51. RESULTS A clonogenic survival assay revealed that CP-751,871 increased the sensitivity of NSCLC cells to radiation in vitro. CP-751,871 inhibited radiation-induced IGF-IR signaling, and potentiated the radiation-induced increases both in the number of apoptotic cells and in the activity of caspase-3. Immunofluorescence analysis of the histone gamma-H2AX and Rad51 also showed that CP-751,871 inhibited the repair of radiation-induced DNA double-strand breaks. Finally, combination therapy with CP-751,871 and radiation delayed the growth of NSCLC tumor xenografts in nude mice to a greater extent than did either treatment modality alone. CONCLUSIONS These results show that CP-751,871 sensitizes NSCLC cells to radiation both in vitro and in vivo, and that this effect of CP-751,871 is likely attributable to the inhibition of DNA repair and enhancement of apoptosis that result from attenuation of IGF-IR signaling. Combined treatment with CP-751,871 and radiation thus warrants further investigation in clinical trials as a potential anticancer strategy.
Collapse
Affiliation(s)
- Tsutomu Iwasa
- Department of Medical Oncology, Kinki University School of Medicine, Osaka-Sayama, Osaka, Japan
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Peerani R, Onishi K, Mahdavi A, Kumacheva E, Zandstra PW. Manipulation of signaling thresholds in "engineered stem cell niches" identifies design criteria for pluripotent stem cell screens. PLoS One 2009; 4:e6438. [PMID: 19649273 PMCID: PMC2713412 DOI: 10.1371/journal.pone.0006438] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 06/30/2009] [Indexed: 12/22/2022] Open
Abstract
In vivo, stem cell fate is regulated by local microenvironmental parameters. Governing parameters in this stem cell niche include soluble factors, extra-cellular matrix, and cell-cell interactions. The complexity of this in vivo niche limits analyses into how individual niche parameters regulate stem cell fate. Herein we use mouse embryonic stem cells (mESC) and micro-contact printing (microCP) to investigate how niche size controls endogenous signaling thresholds. microCP is used to restrict colony diameter, separation, and degree of clustering. We show, for the first time, spatial control over the activation of the Janus kinase/signal transducer and activator of transcription pathway (Jak-Stat). The functional consequences of this niche-size-dependent signaling control are confirmed by demonstrating that direct and indirect transcriptional targets of Stat3, including members of the Jak-Stat pathway and pluripotency-associated genes, are regulated by colony size. Modeling results and empirical observations demonstrate that colonies less than 100 microm in diameter are too small to maximize endogenous Stat3 activation and that colonies separated by more than 400 microm can be considered independent from each other. These results define parameter boundaries for the use of ESCs in screening studies, demonstrate the importance of context in stem cell responsiveness to exogenous cues, and suggest that niche size is an important parameter in stem cell fate control.
Collapse
Affiliation(s)
- Raheem Peerani
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Kento Onishi
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Alborz Mahdavi
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Eugenia Kumacheva
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Peter W. Zandstra
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
| |
Collapse
|
34
|
Schoeberl B, Pace EA, Fitzgerald JB, Harms BD, Xu L, Nie L, Linggi B, Kalra A, Paragas V, Bukhalid R, Grantcharova V, Kohli N, West KA, Leszczyniecka M, Feldhaus MJ, Kudla AJ, Nielsen UB. Therapeutically targeting ErbB3: a key node in ligand-induced activation of the ErbB receptor-PI3K axis. Sci Signal 2009; 2:ra31. [PMID: 19567914 DOI: 10.1126/scisignal.2000352] [Citation(s) in RCA: 262] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The signaling network downstream of the ErbB family of receptors has been extensively targeted by cancer therapeutics; however, understanding the relative importance of the different components of the ErbB network is nontrivial. To explore the optimal way to therapeutically inhibit combinatorial, ligand-induced activation of the ErbB-phosphatidylinositol 3-kinase (PI3K) axis, we built a computational model of the ErbB signaling network that describes the most effective ErbB ligands, as well as known and previously unidentified ErbB inhibitors. Sensitivity analysis identified ErbB3 as the key node in response to ligands that can bind either ErbB3 or EGFR (epidermal growth factor receptor). We describe MM-121, a human monoclonal antibody that halts the growth of tumor xenografts in mice and, consistent with model-simulated inhibitor data, potently inhibits ErbB3 phosphorylation in a manner distinct from that of other ErbB-targeted therapies. MM-121, a previously unidentified anticancer therapeutic designed using a systems approach, promises to benefit patients with combinatorial, ligand-induced activation of the ErbB signaling network that are not effectively treated by current therapies targeting overexpressed or mutated oncogenes.
Collapse
Affiliation(s)
- Birgit Schoeberl
- Merrimack Pharmaceuticals, One Kendall Square, Building 700, Cambridge, MA 02139, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Finzi L, Shao MXG, Paye F, Housset C, Nadel JA. Lipopolysaccharide Initiates a Positive Feedback of Epidermal Growth Factor Receptor Signaling by Prostaglandin E2 in Human Biliary Carcinoma Cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:2269-76. [DOI: 10.4049/jimmunol.0801768] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
36
|
Craciun G, Helton JW, Williams RJ. Homotopy methods for counting reaction network equilibria. Math Biosci 2008; 216:140-9. [PMID: 18824179 DOI: 10.1016/j.mbs.2008.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 08/27/2008] [Accepted: 09/04/2008] [Indexed: 11/16/2022]
Abstract
Dynamical system models of complex biochemical reaction networks are usually high-dimensional, non-linear, and contain many unknown parameters. In some cases the reaction network structure dictates that positive equilibria must be unique for all values of the parameters in the model. In other cases multiple equilibria exist if and only if special relationships between these parameters are satisfied. We describe methods based on homotopy invariance of degree which allow us to determine the number of equilibria for complex biochemical reaction networks and how this number depends on parameters in the model.
Collapse
Affiliation(s)
- Gheorghe Craciun
- Department of Mathematics and Department of Biomolecular Chemistry, University of Wisconsin - Madison, Madison, WI 53706, USA.
| | | | | |
Collapse
|
37
|
Shuryak I, Sachs RK, Brenner DJ. Biophysical Models of Radiation Bystander Effects: 1. Spatial Effects in Three-Dimensional Tissues. Radiat Res 2007; 168:741-9. [DOI: 10.1667/rr1117.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 08/28/2007] [Indexed: 11/03/2022]
|
38
|
Coppey M, Berezhkovskii AM, Sealfon SC, Shvartsman SY. Time and length scales of autocrine signals in three dimensions. Biophys J 2007; 93:1917-22. [PMID: 17720734 PMCID: PMC1959539 DOI: 10.1529/biophysj.107.109736] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A model of autocrine signaling in cultures of suspended cells is developed on the basis of the effective medium approximation. The fraction of autocrine ligands, the mean and distribution of distances traveled by paracrine ligands before binding, as well as the mean and distribution of the ligand lifetime are derived. Interferon signaling by dendritic immune cells is considered as an illustration.
Collapse
Affiliation(s)
- Mathieu Coppey
- Department of Chemical Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | | | | | | |
Collapse
|
39
|
Legewie S, Schoeberl B, Blüthgen N, Herzel H. Competing docking interactions can bring about bistability in the MAPK cascade. Biophys J 2007; 93:2279-88. [PMID: 17526574 PMCID: PMC1965452 DOI: 10.1529/biophysj.107.109132] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/18/2007] [Indexed: 11/18/2022] Open
Abstract
Mitogen-activated protein kinases are crucial regulators of various cell fate decisions including proliferation, differentiation, and apoptosis. Depending on the cellular context, the Raf-Mek-Erk mitogen-activated protein kinase cascade responds to extracellular stimuli in an all-or-none manner, most likely due to bistable behavior. Here, we describe a previously unrecognized positive-feedback mechanism that emerges from experimentally observed sequestration effects in the core Raf-Mek-Erk cascade. Unphosphorylated/monophosphorylated Erk sequesters Mek into Raf-inaccessible complexes upon weak stimulation, and thereby inhibits cascade activation. Mek, once phosphorylated by Raf, triggers Erk phosphorylation, which in turn induces dissociation of Raf-inaccessible Mek-Erk heterodimers, and thus further amplifies Mek phosphorylation. We show that this positive circuit can bring about bistability for parameter values measured experimentally in living cells. Previous studies revealed that bistability can also arise from enzyme depletion effects in the Erk double (de)phosphorylation cycle. We demonstrate that the feedback mechanism proposed in this article synergizes with such enzyme depletion effects to bring about a much larger bistable range than either mechanism alone. Our results show that stable docking interactions and competition effects, which are common in protein kinase cascades, can result in sequestration-based feedback, and thus can have profound effects on the qualitative behavior of signaling pathways.
Collapse
Affiliation(s)
- Stefan Legewie
- Institute for Theoretical Biology, Humboldt University, Berlin, Germany.
| | | | | | | |
Collapse
|
40
|
Paye JMD, Akers RM, Huckle WR, Forsten-Williams K. Autocrine production of insulin-like growth factor-I (IGF-I) affects paracellular transport across epithelial cells in vitro. ACTA ACUST UNITED AC 2007; 14:85-98. [PMID: 17668352 DOI: 10.1080/15419060701463116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Autocrine production of growth factors can have significant effects on cell activity. We report for the first time that autocrine production of insulin-like growth factor-I (IGF-I) alters paracellular transport across bovine mammary epithelial cells in vitro. Paracellular transport was assessed by measuring phenol red transport across mammary alveolar cells-large T antigen (MAC-T cells) derived from parental mammary epithelial cells, cultured on porous membranes and compared with two different transfected MAC-T cell lines that constitutively secrete IGF-I. Phenol red transport was essentially blocked in parental cell culture after six days, while IGF-I secreting cells provided essentially no barrier. Surprisingly, neither co-culture studies between parental and IGF-I-secreting cells nor addition of exogenous IGF-I or IGF-binding protein-3 reversed the phenol red transport properties. IGF-I-secreting cells did however express lower levels of the junction components occludin and E-cadherin than parental cells, suggesting that localized autocrine IGF-I activity might lead to increased permeability via changes in both the tight and adherens junction protein levels.
Collapse
Affiliation(s)
- Julie M D Paye
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg 24061, Virginia, USA
| | | | | | | |
Collapse
|
41
|
Abstract
Transforming growth factor-alpha (TGFalpha) is a member of the epidermal growth factor (EGF) family. Expression of TGFalpha is highly regulated in response to exogenous cellular signals including cytokines and other growth factors. The growth factor has been found to be indispensable for proper development of many tissues and organs. TGFalpha has also been implicated in numerous disease states including forms of breast cancer. This minireview summarizes the basic biology of TGFalpha and its actions during normal and pathogenic development of the mammary epithelium.
Collapse
Affiliation(s)
- Brian W Booth
- Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | |
Collapse
|
42
|
Valerie K, Yacoub A, Hagan MP, Curiel DT, Fisher PB, Grant S, Dent P. Radiation-induced cell signaling: inside-out and outside-in. Mol Cancer Ther 2007; 6:789-801. [PMID: 17363476 DOI: 10.1158/1535-7163.mct-06-0596] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Exposure of tumor cells to clinically relevant doses of ionizing radiation causes DNA damage as well as mitochondria-dependent generation of reactive oxygen species. DNA damage causes activation of ataxia telangiectasia mutated and ataxia telangiectasia mutated and Rad3-related protein, which induce cell cycle checkpoints and also modulate the activation of prosurvival and proapoptotic signaling pathways, such as extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH(2)-terminal kinase 1/2, respectively. Radiation causes a rapid reactive oxygen species-dependent activation of ERBB family and other tyrosine kinases, leading to activation of RAS proteins and multiple protective downstream signaling pathways (e.g., AKT and ERK1/2), which alter transcription factor function and the apoptotic threshold of cells. The initial radiation-induced activation of ERK1/2 can promote the cleavage and release of paracrine ligands, which cause a temporally delayed reactivation of receptors and intracellular signaling pathways in irradiated and unirradiated bystander cells. Hence, signals from within the cell can promote activation of membrane-associated receptors, which signal back into the cytosol: signaling from inside the cell outward to receptors and then inward again via kinase pathways. However, cytosolic signaling can also cause release of membrane-associated paracrine factors, and thus, paracrine signals from outside of the cell can promote activation of growth factor receptors: signaling from the outside inward. The ultimate consequence of these signaling events after multiple exposures may be to reprogram the irradiated and affected bystander cells in terms of their expression levels of growth-regulatory and cell survival proteins, resulting in altered mitogenic rates and thresholds at which genotoxic stresses cause cell death. Inhibition of signaling in one and/or multiple survival pathways enhances radiosensitivity. Prolonged inhibition of any one of these pathways, however, gives rise to lineages of cells, which have become resistant to the inhibitor drug, by evolutionary selection for the clonal outgrowth of cells with point mutations in the specific targeted protein that make the target protein drug resistant or by the reprogramming of multiple signaling processes within all cells, to maintain viability. Thus, tumor cells are dynamic with respect to their reliance on specific cell signaling pathways to exist and rapidly adapt to repeated toxic challenges in an attempt to maintain tumor cell survival.
Collapse
Affiliation(s)
- Kristoffer Valerie
- Department of Biochemistry, Virginia Commonwealth University, 401 College Street, Box 980035, Richmond, VA 23298, USA
| | | | | | | | | | | | | |
Collapse
|
43
|
Yacoub A, Hawkins W, Hanna D, Young H, Park MA, Grant M, Roberts JD, Curiel DT, Fisher PB, Valerie K, Grant S, Hagan MP, Dent P. Human chorionic gonadotropin modulates prostate cancer cell survival after irradiation or HMG CoA reductase inhibitor treatment. Mol Pharmacol 2006; 71:259-75. [PMID: 17050804 DOI: 10.1124/mol.106.031153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The impact of human chorionic gonadotropin (hCG) on prostate carcinoma viability was investigated. Treatment of LNCaP and PC-3 cells with hCG modestly reduced cell viability within 96 h. Treatment of cells with hCG followed by exposure to ionizing radiation enhanced radiosensitivity. Exposure of LNCaP cells to hCG promoted activation of epidermal growth factor receptor (ERBB1) via a Galpha(i)-, mitogen-activated protein kinase kinase (MEK)1/2-, and metalloprotease-dependent paracrine mechanism, effects that were further enhanced after radiation exposure, and that were causal in prolonged intense activation of poly(ADP-ribose) polymerase (PARP). Inhibition of ERBB1, MEK1, or PARP1 function suppressed the radiosensitizing properties of hCG. Radiosensitization was also, in part, dependent upon c-Jun NH2-terminal kinase 1/2 signaling. PARP1-dependent radiosensitization was suppressed by a pan-caspase inhibitor and by knockdown of apoptosis-inducing factor expression. Inhibition of phosphatidylinositol 3-kinase, expression of dominant-negative AKT, or treatment with the HMG CoA reductase inhibitor lovastatin suppressed AKT phosphorylation and enhanced the cytotoxic effects of hCG. The enhancing effect of lovastatin was reproduced by incubation with a geranylgeranyl transferase inhibitor and blocked by coexposure to geranylgeranyl pyrophosphate. Treatment with hCG and lovastatin decreased expression of BCL-(XL) and XIAP, and increased expression of IkappaB. The cytotoxic effects of hCG were enhanced by expression of dominant-negative IkappaB, and they were abolished by coexpression of activated AKT. Expression of activated AKT maintained BCL-(XL) levels in cells expressing dominant-negative IkappaB. The promotion of hCG lethality by lovastatin was abolished by overexpression of BCL-(XL), and was dependent upon activation of caspase-9. Thus, hCG, in combination with radiation and lovastatin, may represent a novel approach to kill prostate cancer cells.
Collapse
Affiliation(s)
- Adly Yacoub
- Department of Biochemistry, 401 College St., Massey Cancer Center, Room 2-108, Box 980035, Virginia Commonwealth University, Richmond VA 23298-0035, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Zak DE, Hao H, Vadigepalli R, Miller GM, Ogunnaike BA, Schwaber JS. Systems analysis of circadian time-dependent neuronal epidermal growth factor receptor signaling. Genome Biol 2006; 7:R48. [PMID: 16784547 PMCID: PMC1779538 DOI: 10.1186/gb-2006-7-6-r48] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 04/05/2006] [Accepted: 05/04/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identifying the gene regulatory networks governing physiological signal integration remains an important challenge in circadian biology. Epidermal growth factor receptor (EGFR) has been implicated in circadian function and is expressed in the suprachiasmatic nuclei (SCN), the core circadian pacemaker. The transcription networks downstream of EGFR in the SCN are unknown but, by analogy to other SCN inputs, we expect the response to EGFR activation to depend on circadian timing. RESULTS We have undertaken a systems-level analysis of EGFR circadian time-dependent signaling in the SCN. We collected gene-expression profiles to study how the SCN response to EGFR activation depends on circadian timing. Mixed-model analysis of variance (ANOVA) was employed to identify genes with circadian time-dependent EGFR regulation. The expression data were integrated with transcription-factor binding predictions through gene group enrichment analyses to generate robust hypotheses about transcription-factors responsible for the circadian phase-dependent EGFR responses. CONCLUSION The analysis results suggest that the transcriptional response to EGFR signaling in the SCN may be partly mediated by established transcription-factors regulated via EGFR transcription-factors (AP1, Ets1, C/EBP), transcription-factors involved in circadian clock entrainment (CREB), and by core clock transcription-factors (Ror alpha). Quantitative real-time PCR measurements of several transcription-factor expression levels support a model in which circadian time-dependent EGFR responses are partly achieved by circadian regulation of upstream signaling components. Our study suggests an important role for EGFR signaling in SCN function and provides an example for gaining physiological insights through systems-level analysis.
Collapse
Affiliation(s)
- Daniel E Zak
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Thomas Jefferson University, Locust St, Philadelphia, PA, USA 19107
- Department of Chemical Engineering, University of Delaware, Academy St, Newark, DE, USA 19716
| | - Haiping Hao
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Thomas Jefferson University, Locust St, Philadelphia, PA, USA 19107
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Thomas Jefferson University, Locust St, Philadelphia, PA, USA 19107
| | - Gregory M Miller
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Thomas Jefferson University, Locust St, Philadelphia, PA, USA 19107
- Department of Chemical Engineering, University of Delaware, Academy St, Newark, DE, USA 19716
| | - Babatunde A Ogunnaike
- Department of Chemical Engineering, University of Delaware, Academy St, Newark, DE, USA 19716
| | - James S Schwaber
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Thomas Jefferson University, Locust St, Philadelphia, PA, USA 19107
| |
Collapse
|
45
|
Walker D, Wood S, Southgate J, Holcombe M, Smallwood R. An integrated agent-mathematical model of the effect of intercellular signalling via the epidermal growth factor receptor on cell proliferation. J Theor Biol 2006; 242:774-89. [PMID: 16765384 DOI: 10.1016/j.jtbi.2006.04.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 04/06/2006] [Accepted: 04/18/2006] [Indexed: 11/18/2022]
Abstract
We have previously developed Epitheliome, a software agent representation of the growth and repair characteristics of epithelial cell populations, where cell behaviour is governed by a number of simple rules. In this paper, we describe how this model has been extended to incorporate an example of a molecular 'mechanism' behind a rule-in this case, how signalling by both endogenous and exogenous ligands of the epidermal growth factor receptor (EGFR) can impact on the proliferation of cell agents. We have developed a mathematical model representing release of endogenous ligand by cells, three-dimensional diffusion of the secreted molecules through a volume of cell culture medium, ligand-receptor binding, and bound receptor internalization and trafficking. Information relating to quantities of molecular species associated with each cell agent is frequently exchanged between the agent and signalling models, and the ratio of bound to free receptors determines cell cycle progression and hence the proliferative behaviour of the cell agents. We have applied this integrated model to examine the effect of plating density on tissue growth via autocrine/paracrine signalling. This predicts that cell growth is dependent on the concentration of exogenous ligand, but where this is limited, then growth becomes dependent on cell density and the availability of endogenous ligand. We have further modified the calcium concentration of the medium to modulate the formation of intercellular bonds between cells and shown that the increased propensity for cells to form colonies in physiological calcium does not result in significantly different patterns of receptor occupancy. In conclusion, our approach demonstrates that by combining agent-based and mathematical modelling paradigms, it is possible to probe the complex feedback relationship between the behaviour of individual cells and their interaction with one another and their environment.
Collapse
Affiliation(s)
- Dawn Walker
- Department of Computer Science, Kroto Institute, North Campus, Broad Lane, Sheffield S3 7HQ, UK.
| | | | | | | | | |
Collapse
|
46
|
Zhdanov VP, Kasemo B. Signaling between cells attached to a surface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:021915. [PMID: 17025480 DOI: 10.1103/physreve.74.021915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 07/10/2006] [Indexed: 05/12/2023]
Abstract
We present a kinetic model allowing one to classify likely scenarios of protein-mediated communication between attached cells of two distinct types. In our treatment, messenger proteins, synthesized in type-1 cells, are considered to penetrate the external membrane of these cells, diffuse in the extracellular medium, associate with the receptors in the external membrane of cells of both types, and induce intracellular signal transduction cascades, influencing the development of cells. Protein degradation inside and outside cells is taken into account as well.
Collapse
Affiliation(s)
- Vladimir P Zhdanov
- Department of Applied Physics, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
| | | |
Collapse
|
47
|
Abstract
Cells often need to respond to multiple opposing signals simultaneously. In this issue of Cell, it is shown that challenging cells with multiple extracellular signals induces an external feedback that involves the release of and response to additional secreted factors with antagonistic functions. These results suggest that an individual cell's decision to die or survive is not wholly independent but depends, at least in part, on feedback from its neighbors.
Collapse
Affiliation(s)
- Alexander Loewer
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | | |
Collapse
|
48
|
Szumiel I. Epidermal growth factor receptor and DNA double strand break repair: the cell's self-defence. Cell Signal 2006; 18:1537-48. [PMID: 16713182 DOI: 10.1016/j.cellsig.2006.03.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 03/21/2006] [Indexed: 01/27/2023]
Abstract
The purpose of this review is to discuss the relation between the repair of DNA double strand breaks (DSB)--the main lethal lesion inflicted by ionising radiation-and the function of receptors of epidermal growth factor (EGFR) and similar ligands (other members of the ERBB family). The reviewed experimental data support the assumption that in mammalian cells, one consequence of EGFR/ERBB activation by X-rays is its internalisation and nuclear translocation together with DNA-dependent protein kinase (DNA-PK) subunits present in lipid rafts or cytoplasm. The effect of EGFR/ERBB stimulation on DSB rejoining would be due to an increase in the nuclear content of DNA-PK subunits and hence, in activity increase of the DNA-PK dependent non-homologous end-joining (D-NHEJ) system. Such mechanism explains the radiosensitising action of "membrane-active drugs", hypertonic media, and other agents that affect nuclear translocation of proteins. Also, one radiosensitising effect of the recently introduced into clinical practice EGFR/ERBB inhibitors would consist on counteracting the nuclear translocation of DNA-PK subunits. In result, D-NHEJ may be less active in inhibitor-treated cells and this will contribute to an enhanced lethal effect of irradiation. The reviewed observations point to a heretofore not understood mechanism of the cell's self-defence against X-rays which can be exploited in combined radio- and chemotherapy.
Collapse
Affiliation(s)
- Irena Szumiel
- Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warszawa, Poland.
| |
Collapse
|
49
|
Wang X, Hao N, Dohlman HG, Elston TC. Bistability, stochasticity, and oscillations in the mitogen-activated protein kinase cascade. Biophys J 2006; 90:1961-78. [PMID: 16361346 PMCID: PMC1386776 DOI: 10.1529/biophysj.105.073874] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 11/21/2005] [Indexed: 11/18/2022] Open
Abstract
Signaling pathways respond to stimuli in a variety of ways, depending on the magnitude of the input and the physiological status of the cell. For instance, yeast can respond to pheromone stimulation in either a binary or graded fashion. Here we present single cell transcription data indicating that a transient binary response in which all cells eventually become activated is typical. Stochastic modeling of the biochemical steps that regulate activation of the mitogen-activated protein kinase Fus3 reveals that this portion of the pathway can account for the graded-to-binary conversion. To test the validity of the model, genetic approaches are used to alter expression levels of Msg5 and Ste7, two of the proteins that negatively and positively regulate Fus3, respectively. Single cell measurements of the genetically altered cells are shown to be consistent with predictions of the model. Finally, computational modeling is used to investigate the effects of protein turnover on the response of the pathway. We demonstrate that the inclusion of protein turnover can lead to sustained oscillations of protein concentrations in the absence of feedback regulation. Thus, protein turnover can profoundly influence the output of a signaling pathway.
Collapse
Affiliation(s)
- Xiao Wang
- Department of Statistics and Operations Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365, USA
| | | | | | | |
Collapse
|
50
|
Abstract
Mechanotransduction may occur through numerous mechanisms, including potentially through autocrine signaling in a dynamically changing extracellular space. We developed a computational model to analyze how alterations in the geometry of an epithelial lateral intercellular space (LIS) affect the concentrations of constitutively shed ligands inside and below the LIS. The model employs the finite element method to solve for the concentration of ligands based on the governing ligand diffusion-convection equations inside and outside of the LIS, and assumes idealized parallel plate geometry and an impermeable tight junction at the apical surface. Using the model, we examined the temporal relationship between geometric changes and ligand concentration, and the dependence of this relationship on system characteristics such as ligand diffusivity, shedding rate, and rate of deformation. Our results reveal how the kinetics of mechanical deformation can be translated into varying rates of ligand accumulation, a potentially important mechanism for cellular discrimination of varying rate-mechanical processes. Furthermore, our results demonstrate that rapid changes in LIS geometry can transiently increase ligand concentrations in underlying media or tissues, suggesting a mechanism for communication of mechanical state between epithelial and subepithelial cells. These results underscore both the plausibility and complexity of the proposed extracellular mechanotransduction mechanism.
Collapse
Affiliation(s)
- Nikola Kojić
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA
| | | | | |
Collapse
|