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Dai B, Liu H, Juan D, Wu K, Cao R. The role of miRNA-29b1 on the hypoxia-induced apoptosis in mammalian cardiomyocytes. Eur J Histochem 2024; 68:4021. [PMID: 38934067 PMCID: PMC11228570 DOI: 10.4081/ejh.2024.4021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/06/2024] [Indexed: 06/28/2024] Open
Abstract
Cardiomyocyte apoptosis is a complex biological process involving the interaction of many factors and signaling pathways. In hypoxic environment, cardiomyocytes may trigger apoptosis due to insufficient energy supply, increased production of oxygen free radicals, and disturbance of intracellular calcium ion balance. The present research aimed to investigate the role of microRNA-29b1 (miR-29b1) in hypoxia-treated cardiomyocytes and its potential mechanism involved. We established an in vitro ischemia model using AC16 and H9C2 cardiomyocytes through hypoxia treatment (1% O2, 48 h). Cell apoptosis was evaluated by flow cytometry using Annexin V FITC-PI staining assay. Moreover, we used Western blot and immunofluorescence analysis to determine the expression of Bcl-2, Bax caspase-3 and Cx43 proteins. We found that miR-29b1 protected AC16 and H9C2 cells from hypoxia-induced injury as evidence that miR-29b1 attenuated the effects of hypoxia treatment on AC16 and H9C2 cell apoptosis after hypoxia treatment. In conclusion, our findings suggest that miR-29b1 may have potential cardiovascular protective effects during ischemia-related myocardial injury.
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Affiliation(s)
- Bo Dai
- Department of Cardiology, The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan.
| | - Hailin Liu
- Department of Cardiology, The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan.
| | - Dingmin Juan
- Department of Cardiology, The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan.
| | - Kaize Wu
- Department of Cardiology, The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan.
| | - Ruhao Cao
- Department of Cardiology, The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan.
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2
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Kandouz M. Cell Death, by Any Other Name…. Cells 2024; 13:325. [PMID: 38391938 PMCID: PMC10886887 DOI: 10.3390/cells13040325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Studies trying to understand cell death, this ultimate biological process, can be traced back to a century ago. Yet, unlike many other fashionable research interests, research on cell death is more alive than ever. New modes of cell death are discovered in specific contexts, as are new molecular pathways. But what is "cell death", really? This question has not found a definitive answer yet. Nevertheless, part of the answer is irreversibility, whereby cells can no longer recover from stress or injury. Here, we identify the most distinctive features of different modes of cell death, focusing on the executive final stages. In addition to the final stages, these modes can differ in their triggering stimulus, thus referring to the initial stages. Within this framework, we use a few illustrative examples to examine how intercellular communication factors in the demise of cells. First, we discuss the interplay between cell-cell communication and cell death during a few steps in the early development of multicellular organisms. Next, we will discuss this interplay in a fully developed and functional tissue, the gut, which is among the most rapidly renewing tissues in the body and, therefore, makes extensive use of cell death. Furthermore, we will discuss how the balance between cell death and communication is modified during a pathological condition, i.e., colon tumorigenesis, and how it could shed light on resistance to cancer therapy. Finally, we briefly review data on the role of cell-cell communication modes in the propagation of cell death signals and how this has been considered as a potential therapeutic approach. Far from vainly trying to provide a comprehensive review, we launch an invitation to ponder over the significance of cell death diversity and how it provides multiple opportunities for the contribution of various modes of intercellular communication.
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Affiliation(s)
- Mustapha Kandouz
- Department of Pathology, School of Medicine, Wayne State University, 540 East Canfield Avenue, Detroit, MI 48201, USA;
- Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA
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3
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Chatchavalvanich S, Boomsma RA, Tietema JM, Geenen DL. Inhibition of Gap Junction Formation Prior to Implantation of Bone Marrow-Derived Mesenchymal Cells Improves Function in the Ischemic Myocardium. Int J Mol Sci 2023; 24:9653. [PMID: 37298612 PMCID: PMC10253678 DOI: 10.3390/ijms24119653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/22/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Bone marrow-derived mesenchymal stem cells (BM-MSC) are reported to induce beneficial effects in the heart following ischemia, but a loss of these cells within hours of implantation could significantly diminish their long-term effect. We hypothesized that early coupling between BM-MSC and ischemic cardiomyocytes through gap junctions (GJ) may play an important role in stem cell survival and retention in the acute phase of myocardial ischemia. To determine the effect of GJ inhibition on murine BM-MSC in vivo, we induced ischemia in mice using 90 min left anterior descending coronary artery (LAD) occlusion followed by BM-MSC implantation and reperfusion. The inhibition of GJ coupling prior to BM-MSC implantation led to early improvement in cardiac function compared to mice in which GJ coupling was not inhibited. Our results with in vitro studies also demonstrated increased survival in BM-MSCs subjected to hypoxia after inhibition of GJ. While functional GJ are critical for the long-term integration of stem cells within the myocardium, early GJ communication may represent a novel paradigm whereby ischemic cardiomyocytes induce a "bystander effect" when coupled to newly transplanted BM-MSC and thus impair cell retention and survival.
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Affiliation(s)
- Santipongse Chatchavalvanich
- Department of Basic Biomedical Sciences, Dr. William M. Scholl College of Podiatric Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA;
| | - Robert A. Boomsma
- Biology Department, Trinity Christian College, Palos Heights, IL 60463, USA;
| | - Jack M. Tietema
- Michigan State University College of Human Medicine, Grand Rapids, MI 49503, USA;
| | - David L. Geenen
- Physician Assistant Studies Department, College of Health Professions, Grand Valley State University, Grand Rapids, MI 49503, USA
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4
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Application of Advanced Non-Linear Spectral Decomposition and Regression Methods for Spectroscopic Analysis of Targeted and Non-Targeted Irradiation Effects in an In-Vitro Model. Int J Mol Sci 2022; 23:ijms232112986. [DOI: 10.3390/ijms232112986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/30/2022] [Accepted: 10/11/2022] [Indexed: 12/24/2022] Open
Abstract
Irradiation of the tumour site during treatment for cancer with external-beam ionising radiation results in a complex and dynamic series of effects in both the tumour itself and the normal tissue which surrounds it. The development of a spectral model of the effect of each exposure and interaction mode between these tissues would enable label free assessment of the effect of radiotherapeutic treatment in practice. In this study Fourier transform Infrared microspectroscopic imaging was employed to analyse an in-vitro model of radiotherapeutic treatment for prostate cancer, in which a normal cell line (PNT1A) was exposed to low-dose X-ray radiation from the scattered treatment beam, and also to irradiated cell culture medium (ICCM) from a cancer cell line exposed to a treatment relevant dose (2 Gy). Various exposure modes were studied and reference was made to previously acquired data on cellular survival and DNA double strand break damage. Spectral analysis with manifold methods, linear spectral fitting, non-linear classification and non-linear regression approaches were found to accurately segregate spectra on irradiation type and provide a comprehensive set of spectral markers which differentiate on irradiation mode and cell fate. The study demonstrates that high dose irradiation, low-dose scatter irradiation and radiation-induced bystander exposure (RIBE) signalling each produce differential effects on the cell which are observable through spectroscopic analysis.
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5
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Demirkıran G, Kalaycı Demir G, Güzeliş C. Coupling of cell fate selection model enhances DNA damage response and may underlie BE phenomenon. IET Syst Biol 2020; 14:96-106. [PMID: 32196468 PMCID: PMC8687165 DOI: 10.1049/iet-syb.2019.0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/24/2019] [Accepted: 10/31/2019] [Indexed: 11/20/2022] Open
Abstract
Double-strand break-induced (DSB) cells send signal that induces DSBs in neighbour cells, resulting in the interaction among cells sharing the same medium. Since p53 network gives oscillatory response to DSBs, such interaction among cells could be modelled as an excitatory coupling of p53 network oscillators. This study proposes a plausible coupling model of three-mode two-dimensional oscillators, which models the p53-mediated cell fate selection in globally coupled DSB-induced cells. The coupled model consists of ATM and Wip1 proteins as variables. The coupling mechanism is realised through ATM variable via a mean-field modelling the bystander signal in the intercellular medium. Investigation of the model reveals that the coupling generates more sensitive DNA damage response by affecting cell fate selection. Additionally, the authors search for the cause-effect relationship between coupled p53 network oscillators and bystander effect (BE) endpoints. For this, they search for the possible values of uncertain parameters that may replicate BE experiments' results. At certain parametric regions, there is a correlation between the outcomes of cell fate and endpoints of BE, suggesting that the intercellular coupling of p53 network may manifest itself as the form of observed BEs.
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Affiliation(s)
- Gökhan Demirkıran
- Electrical and Electronics Engineering, Yaşar University, Selçuk Yaşar Kampüsü, İzmir, Turkey.
| | - Güleser Kalaycı Demir
- Electrical and Electronics Engineering, Dokuz Eylül University, Tınaztepe, İzmir, Turkey
| | - Cüneyt Güzeliş
- Electrical and Electronics Engineering, Yaşar University, Selçuk Yaşar Kampüsü, İzmir, Turkey
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6
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Cotter ML, Boitano S, Lampe PD, Solan JL, Vagner J, Ek-Vitorin JF, Burt JM. The lipidated connexin mimetic peptide SRPTEKT- Hdc is a potent inhibitor of Cx43 channels with specificity for the pS368 phospho-isoform. Am J Physiol Cell Physiol 2019; 317:C825-C842. [PMID: 31365296 PMCID: PMC6850999 DOI: 10.1152/ajpcell.00160.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/16/2019] [Accepted: 07/19/2019] [Indexed: 11/22/2022]
Abstract
Connexin (Cx) mimetic peptides derived from extracellular loop II sequences (e.g., Gap27: SRPTEKTIFII; Peptide5: VDCFLSRPTEKT) have been used as reversible, Cx-specific blockers of hemichannel (HCh) and gap junction channel (GJCh) function. These blockers typically require high concentrations (~5 µM, <1 h for HCh; ~100 µM, >1 h for GJCh) to achieve inhibition. We have shown that addition of a hexadecyl (Hdc) lipid tail to the conserved SRPTEKT peptide sequence (SRPTEKT-Hdc) results in a novel, highly efficacious, and potent inhibitor of mechanically induced Ca2+-wave propagation (IC50 64.8 pM) and HCh-mediated dye uptake (IC50 45.0 pM) in Madin-Darby canine kidney cells expressing rat Cx43 (MDCK43). The lack of similar effect on dye coupling (NBD-MTMA) suggested channel conformation-specific inhibition. Here we report that SRPTEKT-Hdc inhibition of Ca2+-wave propagation, dye coupling, and dye uptake depended on the functional configuration of Cx43 as determined by phosphorylation at serine 368 (S368). Ca2+-wave propagation was enhanced in MDCK cells expressing single-site mutants of Cx43 that mimicked (MDCK43-S368D) or favored (MDCK43-S365A) phosphorylation at S368. Furthermore, SRPTEKT-Hdc potently inhibited GJCh-mediated Ca2+-wave propagation (IC50 230.4 pM), dye coupling, and HCh-mediated dye uptake in MDCK43-S368D and -S365A cells. In contrast, Ca2+-wave propagation, dye coupling, and dye uptake were largely unaffected (IC50 12.3 μM) by SRPTEKT-Hdc in MDCK43-S368A and -S365D cells, mutations that mimic or favor dephosphorylation at S368. Together, these data indicate that SRPTEKT-Hdc is a potent inhibitor of physiological Ca2+-wave signaling mediated specifically by the pS368 phosphorylated form of Cx43.
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Affiliation(s)
- Maura L Cotter
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Scott Boitano
- Department of Physiology, University of Arizona, Tucson, Arizona
- Asthma and Airway Disease Research Center, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Joell L Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Josef Vagner
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Department of Pharmacology, University of Arizona, Tucson, Arizona
| | | | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, Arizona
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Koczurkiewicz P, Klaś K, Grabowska K, Piska K, Rogowska K, Wójcik‐Pszczoła K, Podolak I, Galanty A, Michalik M, Pękala E. Saponins as chemosensitizing substances that improve effectiveness and selectivity of anticancer drug—Minireview of in vitro studies. Phytother Res 2019; 33:2141-2151. [DOI: 10.1002/ptr.6371] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 01/12/2023]
Affiliation(s)
- Paulina Koczurkiewicz
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Katarzyna Klaś
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Karolina Grabowska
- Department of Pharmacognosy, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Kamil Piska
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Katarzyna Rogowska
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Katarzyna Wójcik‐Pszczoła
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Irma Podolak
- Department of Pharmacognosy, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Agnieszka Galanty
- Department of Pharmacognosy, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
| | - Marta Michalik
- Department of Cell Biology, Faculty of Biophysics, Biochemistry and BiotechnologyJagiellonian University Kraków Poland
| | - Elżbieta Pękala
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy Medical CollegeJagiellonian University Kraków Poland
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8
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A Cell Junctional Protein Network Associated with Connexin-26. Int J Mol Sci 2018; 19:ijms19092535. [PMID: 30150563 PMCID: PMC6163694 DOI: 10.3390/ijms19092535] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 02/06/2023] Open
Abstract
GJB2 mutations are the leading cause of non-syndromic inherited hearing loss. GJB2 encodes connexin-26 (CX26), which is a connexin (CX) family protein expressed in cochlea, skin, liver, and brain, displaying short cytoplasmic N-termini and C-termini. We searched for CX26 C-terminus binding partners by affinity capture and identified 12 unique proteins associated with cell junctions or cytoskeleton (CGN, DAAM1, FLNB, GAPDH, HOMER2, MAP7, MAPRE2 (EB2), JUP, PTK2B, RAI14, TJP1, and VCL) by using mass spectrometry. We show that, similar to other CX family members, CX26 co-fractionates with TJP1, VCL, and EB2 (EB1 paralogue) as well as the membrane-associated protein ASS1. The adaptor protein CGN (cingulin) co-immuno-precipitates with CX26, ASS1, and TJP1. In addition, CGN co-immunoprecipitation with CX30, CX31, and CX43 indicates that CX association is independent on the CX C-terminus length or sequence. CX26, CGN, FLNB, and DAMM1 were shown to distribute to the organ of Corti and hepatocyte plasma membrane. In the mouse liver, CX26 and TJP1 co-localized at the plasma membrane. In conclusion, CX26 associates with components of other membrane junctions that integrate with the cytoskeleton.
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9
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Gu Y, Huang F, Wang Y, Chen C, Wu S, Zhou S, Hei Z, Yuan D. Connexin32 plays a crucial role in ROS-mediated endoplasmic reticulum stress apoptosis signaling pathway in ischemia reperfusion-induced acute kidney injury. J Transl Med 2018; 16:117. [PMID: 29728112 PMCID: PMC5935959 DOI: 10.1186/s12967-018-1493-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 04/21/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) not only prolongs the length of hospital stay, but also seriously affects the patient's survival rate. Although our previous investigation has verified that reactive oxygen species (ROS) transferred through gap junction composed of connexin32 (Cx32) contributed to AKI, its underlying mechanisms were not fully understood and viable preventive or therapeutic regimens were still lacking. Among various mechanisms involved in organs I/R-induced injuries, endoplasmic reticulum stress (ERS)-related apoptosis is currently considered to be an important participant. Thus, in present study, we focused on the underlying mechanisms of I/R-induced AKI, and postulated that Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. METHODS We established renal I/R models with Cx32+/+ and Cx32-/- mice, which underwent double kidneys clamping and recanalization. ROS scavenger (N-acetylcysteine, NAC) and ERS inhibitors (4-phenyl butyric acid, 4-PBA, and tauroursodeoxycholic acid, TUDCA) were used to decrease the content of ROS and attenuate ERS activation, respectively. RESULTS Renal damage was progressively exacerbated in a time-dependent manner at the reperfusion stage, that was consistent with the alternation of ERS activation, including glucose regulated protein 78 (BiP/GRP78), X box-binding protein1, and C/EBP homologous protein expression. TUDCA or 4-PBA application attenuated I/R-induced ERS activation and protected against renal tubular epithelial cells apoptosis and renal damage. Cx32 deficiency decreased ROS generation and distribution between the neighboring cells, which attenuated I/R-induced ERS activation, and improved cell apoptosis and renal damage. CONCLUSION Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. Cx32 deficiency, ROS elimination, and ERS inhibition all could protect against I/R-induced AKI.
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Affiliation(s)
- Yu Gu
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Fei Huang
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Yanling Wang
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Chaojin Chen
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Shan Wu
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Shaoli Zhou
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Ziqing Hei
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
| | - Dongdong Yuan
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630 Guangdong Province China
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10
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Cornelius JF, Eismann L, Ebbert L, Senger B, Petridis AK, Kamp MA, Sorg RV, Steiger HJ. 5-Aminolevulinic acid-based photodynamic therapy of chordoma: In vitro experiments on a human tumor cell line. Photodiagnosis Photodyn Ther 2017; 20:111-115. [PMID: 28951177 DOI: 10.1016/j.pdpdt.2017.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/14/2017] [Accepted: 09/17/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND Chordomas are very rare tumors of the skull base and the sacrum. They show infiltrating and destructive growth and are known to be chemo- and radio-resistant. After surgical resection, the recurrence rate is high and overall survival limited. As current adjuvant treatments are ineffective, new treatment concepts are urgently needed. 5-aminolevulinic acid-based photodynamic therapy (5-ALA based PDT) showed promising results for malignant gliomas. However, it is unknown so far, whether chordomas accumulate protoporphyrin IX (PPIX) after application of 5-ALA and whether they are sensitive to subsequent 5-ALA based PDT. METHODS The immortalized human chordoma cells U-CH2 were used as in vitro model. After incubation for 4h or 6h with different 5-ALA concentrations, PPIX accumulation was determined by flow cytometry. To assess sensitivity to PDT, chordoma cells were incubated at 30.000cells/well (high cell density) or 15.000cells/well (low cell density) with graded doses of 5-ALA (0-50μg/ml) in 96-well plates and subsequently exposed to laser light of 635nm wavelength (18.75J/cm2). Cell survival was measured 24h after exposure to laser light using the WST-1 assay. RESULTS U-CH2 cells dose-dependently accumulated PPIX (ANOVA; p<0.0001). PPIX fluorescence was significantly higher, when cells were incubated with 5-ALA for 6h compared to 4h at higher 5-ALA concentrations (ANOVA/Bonferroni; p≤0.05 for≥30μg/ml 5-ALA). For both cell densities, a 5-ALA dose-dependent decline in viability was observed (ANOVA; p<0.0001). Viability was significantly lower at higher 5-ALA concentrations, when 30.000 cells/wells were treated compared to 15.000cells/well (ANOVA/Bonferroni; p≤0.001 for≥30μg/ml 5-ALA). LD50 was 30.25μg/ml 5-ALA. CONCLUSION The human UCH-2 cell line was a very useful in vitro model to study different effects of 5-ALA based PDT. For the first time, it could be shown that human chordoma cells may be destroyed by 5-ALA/PDT.
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Affiliation(s)
- Jan F Cornelius
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany.
| | - Lennert Eismann
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany; Neuro-oncological Research Laboratory, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Lara Ebbert
- Institute for Transplantation Diagnostics and Cell Therapeutics, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Brigitte Senger
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany; Neuro-oncological Research Laboratory, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Athanasios K Petridis
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Marcel Alexander Kamp
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Rüdiger V Sorg
- Institute for Transplantation Diagnostics and Cell Therapeutics, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Hans Jakob Steiger
- Department of Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
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11
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Zhang Y, Tan X, Xue L. The alpha2-adrenoreceptor agonist dexmedetomidine protects against lipopolysaccharide-induced apoptosis via inhibition of gap junctions in lung fibroblasts. Biochem Biophys Res Commun 2017; 495:92-97. [PMID: 29101030 DOI: 10.1016/j.bbrc.2017.10.162] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 10/29/2017] [Indexed: 01/20/2023]
Abstract
The α2-adrenoceptor inducer dexmedetomidine protects against acute lung injury (ALI), but the mechanism of this effect is largely unknown. The present study investigated the effect of dexmedetomidine on apoptosis induced by lipopolysaccharide (LPS) and the relationship between this effect and gap junction intercellular communication in human lung fibroblast cell line. Flow cytometry was used to detect apoptosis induced by LPS. Parachute dye coupling assay was used to measure gap junction function, and western blot analysis was used to determine the expression levels of connexin43 (Cx43). The results revealed that exposure of human lung fibroblast cell line to LPS for 24 h increased the apoptosis, and pretreatment of dexmedetomidine and 18α-GA significantly reduced LPS-induced apoptosis. Dexmedetomidine exposure for 1 h inhibited gap junction function mainly via a decrease in Cx43 protein levels in human lung fibroblast cell line. These results demonstrated that the inhibition of gap junction intercellular communication by dexmedetomidine affected the LPS-induced apoptosis through inhibition of gap junction function by reducing Cx43 protein levels. The present study provides evidence of a novel mechanism underlying the effects of analgesics in counteracting ALI.
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Affiliation(s)
- Yuan Zhang
- Department of Pharmacy, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan 511518, People's Republic of China.
| | - Xiaoming Tan
- Department of Pharmacy, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan 511518, People's Republic of China
| | - Lianfang Xue
- Department of Pharmacy, The First Affiliated Hospital of Jinan University, Guangzhou 510630, People's Republic of China
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12
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Multiple and complex influences of connexins and pannexins on cell death. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017. [PMID: 28625689 DOI: 10.1016/j.bbamem.2017.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cell death is a fundamental process for organogenesis, immunity and cell renewal. During the last decades a broad range of molecular tools were identified as important players for several different cell death pathways (apoptosis, pyroptosis, necrosis, autosis…). Aside from these direct regulators of cell death programs, several lines of evidence proposed connexins and pannexins as potent effectors of cell death. In the present review we discussed the potential roles played by connexins, pannexins and innexins in the different cell death programs at different scales from gap junction intercellular communication to protein-protein interactions. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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13
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Bystander effects elicited by single-cell photo-oxidative blue-light stimulation in retinal pigment epithelium cell networks. Cell Death Discov 2017; 3:16071. [PMID: 28179989 PMCID: PMC5292780 DOI: 10.1038/cddiscovery.2016.71] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/26/2016] [Accepted: 08/19/2016] [Indexed: 02/07/2023] Open
Abstract
‘Bystander effect’ refers to the induction of biological effects in cells not directly targeted. The retinal pigment epithelium consists of hexagonal cells, forming a monolayer interconnected by gap junctions (GJs). Oxidative stress initiated in an individual cell by photostimulation (488 nm) triggered changes in reactive oxygen species (ROS), Ca2+ and mitochondrial membrane potential (ψm). The Ca2+ signal was transmitted to neighboring cells slowly and non-uniformly; the ROS signal spread fast and radially. Increased Ca2+ levels were associated with a loss in ψm. GJ blockers prevented the spreading of the Ca2+, but not the ROS-related signal. The GJ-mediated Ca2+ wave was associated with cell death by 24 h, requiring endoplasmic reticulum–mitochondria Ca2+ transfer. Ensuing cell death was correlated with baseline Ca2+ levels, and baseline Ca2+ levels were correlated with pigmentation. Hence, local oxidative stress in a donor cell can trigger changes in certain connected recipient cells, a signal that required GJ communication and an ROS-Ca2+ dual-hit. Finally, damage apparently occurred in susceptible cells, which correlated with baseline Ca2+ levels.
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Mazumder S, De R, Sarkar S, Siddiqui AA, Saha SJ, Banerjee C, Iqbal MS, Nag S, Debsharma S, Bandyopadhyay U. Selective scavenging of intra-mitochondrial superoxide corrects diclofenac-induced mitochondrial dysfunction and gastric injury: A novel gastroprotective mechanism independent of gastric acid suppression. Biochem Pharmacol 2016; 121:33-51. [PMID: 27693316 DOI: 10.1016/j.bcp.2016.09.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/27/2016] [Indexed: 12/22/2022]
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to treat multiple inflammatory diseases and pain but severe gastric mucosal damage is the worst outcome of NSAID-therapy. Here we report that mitoTEMPO, a mitochondrially targeted superoxide (O2-) scavenger protected as well as healed gastric injury induced by diclofenac (DCF), the most commonly used NSAID. Common existing therapy against gastric injury involves suppression of gastric acid secretion by proton pump inhibitors and histamine H2 receptor antagonists; however, dyspepsia, vitamin B12 deficiency and gastric microfloral dysbalance are the major drawbacks of acid suppression. Interestingly, mitoTEMPO did not inhibit gastric acid secretion but offered gastroprotection by preventing DCF-induced generation of O2- due to mitochondrial respiratory chain failure and by preventing mitochondrial oxidative stress (MOS)-mediated mitopathology. MitoTEMPO even restored DCF-stimulated reduced fatty acid oxidation, mitochondrial depolarization and bioenergetic crisis in gastric mucosa. MitoTEMPO also prevented the activation of mitochondrial pathway of apoptosis and MOS-mediated proinflammatory signaling through NF-κB by DCF. Furthermore, mitoTEMPO when administered in rats with preformed gastric lesions expedited the healing of gastric injury and the healed stomach exhibited its normal physiology as evident from gastric acid and pepsin secretions under basal or stimulated conditions. Thus, in contrast to the existing antiulcer drugs, mitochondrially targeted O2- scavengers like mitoTEMPO may represent a novel class of gastroprotective molecules that does not affect gastric acid secretion and may be used in combination with DCF, keeping its anti-inflammatory action intact, while reducing its gastrodamaging effects.
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Affiliation(s)
- Somnath Mazumder
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Rudranil De
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Souvik Sarkar
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Asim Azhar Siddiqui
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Shubhra Jyoti Saha
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Chinmoy Banerjee
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Mohd Shameel Iqbal
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Shiladitya Nag
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Subhashis Debsharma
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, West Bengal, India.
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Dexmedetomidine protects against apoptosis induced by hypoxia/reoxygenation through the inhibition of gap junctions in NRK-52E cells. Life Sci 2014; 122:72-7. [PMID: 25529146 DOI: 10.1016/j.lfs.2014.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 11/29/2014] [Accepted: 12/08/2014] [Indexed: 11/23/2022]
Abstract
AIMS The α2-adrenoceptor inducer dexmedetomidine (Dex) provides renoprotection against ischemia/reperfusion (I/R) injury, but the mechanism of this effect is largely unknown. The present study investigated the effect of Dex on apoptosis induced by hypoxia/reoxygenation (H/R) and the relationship between this effect and gap junction intercellular communication (GJIC). MAIN METHODS In vitro, two cell lines of normal rat kidney proximal tubular cells (NRK-52E) and HeLa cells that were transfected with a connexin 32 (Cx32) plasmid were exposed to H/R. The role of Dex in the modulation of H/R-induced apoptosis was explored by the manipulation of connexin expression, and hence gap junction (GJ) function, using a GJIC inhibitor, heptanol, and a GJIC inducer, retinoic acid. GJ function and the Cx32 protein level were determined by the parachute dye-coupling assay and Western blotting, respectively. KEY FINDINGS Dex and heptanol significantly reduced H/R-induced apoptosis in NRK-52E cells. The anti-apoptosis effect of Dex was exhibited only in Cx32-expressing HeLa cells. One hour Dex exposure inhibited GJ function mainly via a decrease in Cx32 protein levels in NRK-52E cells. SIGNIFICANCE Our data suggest that Dex reduced H/R-induced apoptosis through the inhibition of GJ activity by reducing Cx32 protein levels.
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Carette D, Gilleron J, Chevallier D, Segretain D, Pointis G. Connexin a check-point component of cell apoptosis in normal and physiopathological conditions. Biochimie 2014; 101:1-9. [DOI: 10.1016/j.biochi.2013.11.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 11/18/2013] [Indexed: 12/16/2022]
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DING WENTING, ZHOU LEQUAN, LIU WEI, GUAN LI, LI XIAOYING, LIU HAIMEI, YAN FUMAN, XU JINWEN, ZENG WEIYONG, QIU MIN. Opposite effects of the gap junction blocker octanol on focal cerebral ischemia occluded for different durations. Mol Med Rep 2014; 9:2485-90. [PMID: 24676712 DOI: 10.3892/mmr.2014.2075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 03/07/2014] [Indexed: 11/05/2022] Open
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Jung J, Weisenburger S, Albert S, Gilbert DF, Friedrich O, Eulenburg V, Kornhuber J, Groemer TW. Performance of scientific cameras with different sensor types in measuring dynamic processes in fluorescence microscopy. Microsc Res Tech 2013; 76:835-43. [DOI: 10.1002/jemt.22236] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/19/2013] [Accepted: 04/26/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Jasmin Jung
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91054 Germany
| | - Siegfried Weisenburger
- Nano-Optics Division, Max Planck Institute for the Science of Light; Erlangen 91058 Germany
| | - Sahradha Albert
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91054 Germany
| | - Daniel F. Gilbert
- Institute of Medical Biotechnology; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91052 Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91052 Germany
| | - Volker Eulenburg
- Department of Biochemistry and Molecular Medicine; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91054 Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91054 Germany
| | - Teja W. Groemer
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen 91054 Germany
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Kim JK, Jackson TL. Mechanisms that enhance sustainability of p53 pulses. PLoS One 2013; 8:e65242. [PMID: 23755198 PMCID: PMC3670918 DOI: 10.1371/journal.pone.0065242] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/26/2013] [Indexed: 02/07/2023] Open
Abstract
The tumor suppressor p53 protein shows various dynamic responses depending on the types and extent of cellular stresses. In particular, in response to DNA damage induced by γ-irradiation, cells generate a series of p53 pulses. Recent research has shown the importance of sustaining repeated p53 pulses for recovery from DNA damage. However, far too little attention has been paid to understanding how cells can sustain p53 pulses given the complexities of genetic heterogeneity and intrinsic noise. Here, we explore potential molecular mechanisms that enhance the sustainability of p53 pulses by developing a new mathematical model of the p53 regulatory system. This model can reproduce many experimental results that describe the dynamics of p53 pulses. By simulating the model both deterministically and stochastically, we found three potential mechanisms that improve the sustainability of p53 pulses: 1) the recently identified positive feedback loop between p53 and Rorα allows cells to sustain p53 pulses with high amplitude over a wide range of conditions, 2) intrinsic noise can often prevent the dampening of p53 pulses even after mutations, and 3) coupling of p53 pulses in neighboring cells via cytochrome-c significantly reduces the chance of failure in sustaining p53 pulses in the presence of heterogeneity among cells. Finally, in light of these results, we propose testable experiments that can reveal important mechanisms underlying p53 dynamics.
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Affiliation(s)
- Jae Kyoung Kim
- Department of Mathematics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Trachette L. Jackson
- Department of Mathematics, University of Michigan, Ann Arbor, Michigan, United States of America
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Chang WW, Lai CH, Chen MC, Liu CF, Kuan YD, Lin ST, Lee CH. Salmonella enhance chemosensitivity in tumor through connexin 43 upregulation. Int J Cancer 2013; 133:1926-35. [PMID: 23558669 DOI: 10.1002/ijc.28155] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 02/21/2013] [Indexed: 01/30/2023]
Abstract
The use of preferentially replicating bacteria as oncolytic agents is one of the innovative approaches for the treatment of cancer. The capability of Salmonella to disperse within tumors and hence to delay tumor growth was augmented when combined with chemotherapy. This work is warranted to elucidate the underlying mechanism of antitumor effects by the combination therapy of Salmonella and cisplatin. The presence of functional gap junctions is highly relevant for the success of chemotherapy. Following Salmonella treatment, dose- and time-dependent upregulation of connexin 43 (Cx43) expressions were observed. Moreover, Salmonella significantly enhanced gap intercellular communication (GJIC), as revealed by the fluorescent dye scrape loading assay. To study the pathway underlying these Salmonella-induced effects, we found that Salmonella induced a significant increase in mitogen-activated protein kinases (MAPK) signaling pathways. The Salmonella-induced upregulation of Cx43 was prevented by treatment of cells with the phosphorylated p38 inhibitor, but not phosphorylated extracellular signal-regulated kinase (pERK) inhibitor or phosphorylated c-jun N terminal kinase (pJNK) inhibitor. Specific knockdown of Cx43 had an inhibitory effect on GJIC and resulted in a reduction of cell death after Salmonella and cisplatin treatment. Our results suggest that accumulation of Salmonella in tumor sites leads to increase Cx43 gap junction communication and enhances the combination of Salmonella and cisplatin therapeutic effects.
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Affiliation(s)
- Wen-Wei Chang
- Department of Biomedical Sciences, College of Medical Science and Technology, Chung Shan Medical University, Taichung, Taiwan
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Decrock E, De Bock M, Wang N, Gadicherla AK, Bol M, Delvaeye T, Vandenabeele P, Vinken M, Bultynck G, Krysko DV, Leybaert L. IP3, a small molecule with a powerful message. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1772-86. [PMID: 23291251 DOI: 10.1016/j.bbamcr.2012.12.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022]
Abstract
Research conducted over the past two decades has provided convincing evidence that cell death, and more specifically apoptosis, can exceed single cell boundaries and can be strongly influenced by intercellular communication networks. We recently reported that gap junctions (i.e. channels directly connecting the cytoplasm of neighboring cells) composed of connexin43 or connexin26 provide a direct pathway to promote and expand cell death, and that inositol 1,4,5-trisphosphate (IP3) diffusion via these channels is crucial to provoke apoptosis in adjacent healthy cells. However, IP3 itself is not sufficient to induce cell death and additional factors appear to be necessary to create conditions in which IP3 will exert proapoptotic effects. Although IP3-evoked Ca(2+) signaling is known to be required for normal cell survival, it is also actively involved in apoptosis induction and progression. As such, it is evident that an accurate fine-tuning of this signaling mechanism is crucial for normal cell physiology, while a malfunction can lead to cell death. Here, we review the role of IP3 as an intracellular and intercellular cell death messenger, focusing on the endoplasmic reticulum-mitochondrial synapse, followed by a discussion of plausible elements that can convert IP3 from a physiological molecule to a killer substance. Finally, we highlight several pathological conditions in which anomalous intercellular IP3/Ca(2+) signaling might play a role. This article is part of a Special Issue entitled:12th European Symposium on Calcium.
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Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences, Ghent University, Ghent, Belgium
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22
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Abstract
In the mammalian CNS, excessive release of glutamate and overactivation of glutamate receptors are responsible for the secondary (delayed) neuronal death following neuronal injury, including ischemia, traumatic brain injury (TBI) and epilepsy. The coupling of neurons by gap junctions (electrical synapses) increases during neuronal injury. In a recent study with the use of in vivo and in vitro models of cortical ischemia in mice, we have demonstrated that the ischemic increase in neuronal gap junction coupling is regulated by glutamate via group II metabotropic glutamate receptors (mGluR). Specifically, we found that activation of group II mGluRs increases background levels of neuronal gap junction coupling and expression of connexin 36 (Cx36; neuronal gap junction protein), whereas inactivation of group II mGluRs prevents the ischemia-mediated increases in the coupling and Cx36 expression. Using the analysis of neuronal death, we also established that inactivation of group II mGluRs or genetic elimination of Cx36 both dramatically reduce ischemic neuronal death in vitro and in vivo. Similar results were obtained using in vitro models of TBI and epilepsy. Our study demonstrated that mechanisms for the injury-mediated increase in neuronal gap junction coupling are part of the mechanisms for glutamate-dependent neuronal death.
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Affiliation(s)
- Andrei B Belousov
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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Jin C, Wu S, Lu X, Liu Q, Zhang L, Yang J, Xi Q, Cai Y. Conditioned medium from actinomycin D-treated apoptotic cells induces mitochondria-dependent apoptosis in bystander cells. Toxicol Lett 2012; 211:45-53. [PMID: 22421271 DOI: 10.1016/j.toxlet.2012.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/25/2012] [Accepted: 02/27/2012] [Indexed: 10/28/2022]
Abstract
Chemical-induced bystander effects have been known for several years, but the underlying mechanism is still seldom investigated. Previous researchers have found that mitomycin C and phleomycin induced micronuclei in bystander cells the same as in exposed cells. We previously demonstrated the ability of actinomycin D (ACTD) to induce bystander effects in normal Chinese hamster fibroblast V79 cells and found that conditioned medium (CM) obtained from ACTD-exposed apoptotic cells induced apoptosis in bystander cells. The present study further explores the probable mechanism of apoptosis in bystander cells. The main findings of this study are: (1) ACTD-treated CM induced apoptosis in bystander cells in a time-dependent manner, which was confirmed with morphological changes. (2) ACTD-treated CM increased the mRNA and protein levels of pro-apoptotic p53 and Bax, whereas it decreased those of anti-apoptotic Bcl-2 in bystander cells; these were all time-dependent effects. Reactive oxygen species (ROS) were also involved in apoptosis of bystander cells. (3) ACTD-treated CM reduced mitochondria membrane potential and induced cytochrome c release. (4) ACTD-treated CM induced G1 cell phase arrest, which may be another response in bystander cells when cultured with CM. These results suggest that chemical-treated CM induces p53-Bcl-2/Bax-cytochrome c signaling (i.e., mitochondria pathway)-dependent apoptosis in bystander cells, which is a kinetic response.
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Affiliation(s)
- Cuihong Jin
- Department of Toxicology, School of Public Health, China Medical University, Shenyang 110001, PR China
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Cytochrome-c mediated a bystander response dependent on inducible nitric oxide synthase in irradiated hepatoma cells. Br J Cancer 2012; 106:889-95. [PMID: 22274409 PMCID: PMC3305951 DOI: 10.1038/bjc.2012.9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Radiation-induced bystander effect (RIBE) has important implication in tumour radiotherapy, but the bystander signals are still not well known. METHODS The role of cytochrome-c (cyt-c) and free radicals in RIBE on human hepatoma cells HepG2 was investigated by detecting the formation of bystander micronuclei (MN) and the generation of endogenous cyt-c, inducible nitric oxide (NO) synthase (iNOS), NO, and reactive oxygen species (ROS) molecules. RESULTS When HepG2 cells were cocultured with an equal number of irradiated HepG2 cells, the yield of MN in the nonirradiated bystander cells was increased in a manner depended on radiation dose and cell coculture time, but it was diminished when the cells were treated with cyclosporin A (CsA), an inhibitor of cyt-c release. Meanwhile the CsA treatment inhibited radiation-induced NO but not ROS. Both of the depressed bystander effect and NO generation in the CsA-treated cells were reversed when 5 μM cyt-c was added in the cell coculture medium. But these exogenous cyt-c-mediated overproductions of NO and bystander MN were abolished when the cells were pretreated with s-methylisothiourea sulphate, an iNOS inhibitor. CONCLUSION Radiation-induced cyt-c has a profound role in regulating bystander response through an iNOS-triggered NO signal but not ROS in HepG2 cells.
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Wang Y, Song JH, Denisova JV, Park WM, Fontes JD, Belousov AB. Neuronal gap junction coupling is regulated by glutamate and plays critical role in cell death during neuronal injury. J Neurosci 2012; 32:713-25. [PMID: 22238107 PMCID: PMC3567463 DOI: 10.1523/jneurosci.3872-11.2012] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/10/2011] [Accepted: 10/31/2011] [Indexed: 11/21/2022] Open
Abstract
In the mammalian CNS, excessive release of glutamate and overactivation of glutamate receptors are responsible for the secondary (delayed) neuronal death following neuronal injury, including ischemia, traumatic brain injury (TBI), and epilepsy. The coupling of neurons by gap junctions (electrical synapses) increases during neuronal injury. We report here that the ischemic increase in neuronal gap junction coupling is regulated by glutamate via group II metabotropic glutamate receptors (mGluRs). Specifically, using electrotonic coupling, Western blots, and siRNA in the mouse somatosensory cortex in vivo and in vitro, we demonstrate that activation of group II mGluRs increases background levels of neuronal gap junction coupling and expression of connexin 36 (Cx36) (neuronal gap junction protein), and inactivation of group II mGluRs prevents the ischemia-mediated increases in the coupling and Cx36 expression. We also show that the regulation is via cAMP/PKA (cAMP-dependent protein kinase)-dependent signaling and posttranscriptional control of Cx36 expression and that other glutamate receptors are not involved in these regulatory mechanisms. Furthermore, using the analysis of neuronal death, we show that inactivation of group II mGluRs or genetic elimination of Cx36 both dramatically reduce ischemia-mediated neuronal death in vitro and in vivo. Similar results are obtained using in vitro models of TBI and epilepsy. Our results indicate that neuronal gap junction coupling is a critical component of glutamate-dependent neuronal death. They also suggest that causal link among group II mGluR function, neuronal gap junction coupling, and neuronal death has a universal character and operates in different types of neuronal injuries.
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Affiliation(s)
- Yongfu Wang
- Departments of Molecular and Integrative Physiology and
| | - Ji-Hoon Song
- Departments of Molecular and Integrative Physiology and
| | | | - Won-Mee Park
- Departments of Molecular and Integrative Physiology and
| | - Joseph D. Fontes
- Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160
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Transfer of IP₃ through gap junctions is critical, but not sufficient, for the spread of apoptosis. Cell Death Differ 2011; 19:947-57. [PMID: 22117194 DOI: 10.1038/cdd.2011.176] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Decades of research have indicated that gap junction channels contribute to the propagation of apoptosis between neighboring cells. Inositol 1,4,5-trisphosphate (IP₃) has been proposed as the responsible molecule conveying the apoptotic message, although conclusive results are still missing. We investigated the role of IP₃ in a model of gap junction-mediated spreading of cytochrome C-induced apoptosis. We used targeted loading of high-molecular-weight agents interfering with the IP₃ signaling cascade in the apoptosis trigger zone and cell death communication zone of C6-glioma cells heterologously expressing connexin (Cx)43 or Cx26. Blocking IP₃ receptors or stimulating IP₃ degradation both diminished the propagation of apoptosis. Apoptosis spread was also reduced in cells expressing mutant Cx26, which forms gap junctions with an impaired IP₃ permeability. However, IP₃ by itself was not able to induce cell death, but only potentiated cell death propagation when the apoptosis trigger was applied. We conclude that IP₃ is a key necessary messenger for communicating apoptotic cell death via gap junctions, but needs to team up with other factors to become a fully pro-apoptotic messenger.
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Yanicostas C, Soussi-Yanicostas N, El-Khoury R, Bénit P, Rustin P. Developmental aspects of respiratory chain from fetus to infancy. Semin Fetal Neonatal Med 2011; 16:175-80. [PMID: 21640674 DOI: 10.1016/j.siny.2011.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Reviewing the recent literature on the role of mitochondria during fetal development paradoxically reveals two features: the importance of mitochondria in these early developmental phases, and the scarcity of information available for humans. Indeed, most of the available information on the role of mitochondria during development comes from studies of animal models that do not necessarily strictly apply to humans. In this paper, we attempted to collect information existing on humans, together with data from animal studies essentially presented as corroboration. This makes clear that a complex interacting network of energetic, genetic and epigenetic factors governs the impact of mitochondrial function on early development in humans. This complexity presumably also accounts for our poor understanding of the consequences of impaired mitochondrial function on prenatal development, or conversely, of the impact of development on the expression of such deficiencies.
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28
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Decrock E, Vinken M, Bol M, D'Herde K, Rogiers V, Vandenabeele P, Krysko DV, Bultynck G, Leybaert L. Calcium and connexin-based intercellular communication, a deadly catch? Cell Calcium 2011; 50:310-21. [PMID: 21621840 DOI: 10.1016/j.ceca.2011.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Ca(2+) is known as a universal messenger mediating a wide variety of cellular processes, including cell death. In fact, this ion has been proposed as the 'cell death master', not only at the intracellular but also at the intercellular level. The most direct form of intercellular spread of cell death is mediated by gap junction channels. These channels have been shown to propagate cell death as well as cell survival signals between the cytoplasm of neighbouring cells, reflecting the dual role of Ca(2+) signals, i.e. cell death versus survival. Its precursor, the unopposed hemichannel (half of a gap junction channel), has recently joined in as a toxic pore connecting the intracellular with the extracellular environment and allowing the passage of a range of substances. The biochemical nature of the so-called intercellular cell death molecule, transferred through gap junctions or released/taken up via hemichannels, remains elusive but several studies pinpoint Ca(2+) itself or its messenger inositol trisphosphate as the responsible masters in crime. Although direct evidence is still lacking, indirect data including Ca(2+) involvement in intercellular communication and cell death, and effects of intercellular communication on intracellular Ca(2+) homeostasis, support this hypothesis. In addition, hemichannels and their molecular building blocks, connexin or pannexin proteins, may exert their effects on Ca(2+)-dependent cell death at the intracellular level, independently from their channel functions. This review provides a cutting edge overview of the current knowledge and underscores the intimate connection between intercellular communication, Ca(2+) signalling and cell death.
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Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences - Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
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Peixoto PM, Dejean LM, Kinnally KW. The therapeutic potential of mitochondrial channels in cancer, ischemia-reperfusion injury, and neurodegeneration. Mitochondrion 2011; 12:14-23. [PMID: 21406252 DOI: 10.1016/j.mito.2011.03.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 02/23/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
Abstract
Mitochondria communicate with the rest of the cell through channels located in their inner and outer membranes. Most of the time, the message is encoded by the flow of anions and cations e.g., through VDAC and PTP, respectively. However, proteins are also both imported and exported across the mitochondrial membranes e.g., through TOM and MAC, respectively. Transport through mitochondrial channels is exquisitely regulated and controls a myriad of processes; from energy production to cell death. Here, we examine the role of some of the mitochondrial channels involved in neurodegeneration, ischemia-reperfusion injury and cancer in the context of their potential as therapeutic targets.
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Affiliation(s)
- Pablo M Peixoto
- New York University, College of Dentistry, 345 East 24th Street, New York, NY 10010, United States
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Peixoto PM, Lue JK, Ryu SY, Wroble BN, Sible JC, Kinnally KW. Mitochondrial apoptosis-induced channel (MAC) function triggers a Bax/Bak-dependent bystander effect. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 178:48-54. [PMID: 21224042 DOI: 10.1016/j.ajpath.2010.11.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 08/20/2010] [Accepted: 09/14/2010] [Indexed: 02/08/2023]
Abstract
Collateral spread of apoptosis to nearby cells is referred to as the bystander effect, a process that is integral to tissue homeostasis and a challenge to anticancer therapies. In many systems, apoptosis relies on permeabilization of the mitochondrial outer membrane to factors such as cytochrome c and Smac/DIABLO. This permeabilization occurs via formation of a mitochondrial apoptosis-induced channel (MAC) and was mimicked here by single-cell microinjection of cytochrome c into Xenopus laevis embryos. Waves of apoptosis were observed in vivo from the injected to the neighboring cells. This finding indicates that a death signal generated downstream of cytochrome c release diffused to neighboring cells and ultimately killed the animals. The role of MAC in bystander effects was then assessed in mouse embryonic fibroblasts that did or did not express its main components, Bax and/or Bak. Exogenous expression of green fluorescent protein-Bax triggered permeabilization of the outer membrane and apoptosis in these cells. Time-lapse videos showed that neighboring cells also underwent apoptosis, but expression of Bax and/or Bak was essential to this effect, because no bystanders were observed in cells lacking both of these MAC components. These results may guide development of novel therapeutic strategies to selectively eliminate tumors or minimize the size of tissue injury in degenerative or traumatic cell death.
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Affiliation(s)
- Pablo M Peixoto
- Department of Basic Sciences, New York University College of Dentistry, New York, New York, USA
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He M, Zhao M, Shen B, Prise KM, Shao C. Radiation-induced intercellular signaling mediated by cytochrome-c via a p53-dependent pathway in hepatoma cells. Oncogene 2010; 30:1947-55. [PMID: 21132005 DOI: 10.1038/onc.2010.567] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The tumor suppressor p53 has a crucial role in cellular response to DNA damage caused by ionizing radiation, but it is still unclear whether p53 can modulate radiation-induced bystander effects (RIBE). In the present work, three different hepatoma cell lines, namely HepG2 (wild p53), PLC/PRF/5 (mutation p53) and Hep3B (p53 null), were irradiated with γ-rays and then co-cultured with normal Chang liver cell (wild p53) in order to elucidate the mechanisms of RIBE. Results showed that the radiosensitivity of HepG2 cells was higher than that of PLC/PRF/5 and Hep3B cells. Only irradiated HepG2 cells, rather than irradiated PLC/PRF/5 or Hep3B cells, could induce bystander effect of micronuclei (MN) formation in the neighboring Chang liver cells. When HepG2 cells were treated with 20 μM pifithrin-α, an inhibitor of p53 function, or 5 μM cyclosporin A (CsA), an inhibitor of cytochrome-c release from mitochondria, the MN induction in bystander Chang liver cells was diminished. In fact, it was found that after irradiation, cytochrome-c was released from mitochondria into the cytoplasm only in HepG2 cells in a p53-dependent manner, but not in PLC/PRF/5 and Hep3B cells. Interestingly, when 50 μg/ml exogenous cytochrome-c was added into cell co-culture medium, RIBE was significantly triggered by irradiated PLC/PRF/5 and Hep3B cells, which previously failed to provoke a bystander effect. In addition, this exogenous cytochrome-c also partly recovered the RIBE induced by irradiated HepG2 cells even with CsA treatment. Our results provide new evidence that the RIBE can be modulated by the p53 status of irradiated hepatoma cells and that a p53-dependent release of cytochrome-c may be involved in the RIBE.
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Affiliation(s)
- M He
- Institute of Radiation Medicine, Fudan University, Shanghai, China
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Kandouz M, Batist G. Gap junctions and connexins as therapeutic targets in cancer. Expert Opin Ther Targets 2010; 14:681-92. [PMID: 20446866 DOI: 10.1517/14728222.2010.487866] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
IMPORTANCE OF THE FIELD Connexins (Cxs) and gap junctional intercellular communications (GJICs) play roles in cancer development, growth and metastasis. Experimental studies suggest that targeting Cxs may be a novel technique, either to inhibit tumor cell growth directly or to sensitize to various therapies. AREAS COVERED IN THIS REVIEW A brief introduction to the role of Cxs in cancer. The focus is mainly on data available in the literature regarding therapeutic aspects. WHAT THE READER WILL GAIN This article reviews the various strategies that take advantage of gap junctions and connexins to eliminate cancer cells, including use of the bystander effect (BE) in gene therapy, the effect of connexins on chemosensitization, the role of apoptotic processes and interactions with the microenvironment. Attempts to restore connexin expression at the transcriptional and post-transcriptional levels are described, as well as promising strategies recently explored. The potential and limitations of the approaches are discussed. TAKE HOME MESSAGE Connexins have multiple facets, singly, in hemichannel complexes, in gap junctions or interacting with different proteins. The regulation of their expression is not fully resolved and selective manipulation of Cxs expression is therefore a challenge. Although the therapeutic potential of connexins is undeniable, more effort is needed to study the regulation and functions of these proteins.
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Affiliation(s)
- Mustapha Kandouz
- Wayne State University, Department of Pathology, 5101 Cass Avenue, Chemistry Building, Detroit, Michigan 48202, USA.
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Peixoto PM, Ryu SY, Kinnally KW. Mitochondrial ion channels as therapeutic targets. FEBS Lett 2010; 584:2142-52. [PMID: 20178788 PMCID: PMC2872129 DOI: 10.1016/j.febslet.2010.02.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/12/2010] [Accepted: 02/16/2010] [Indexed: 12/31/2022]
Abstract
The study of mitochondrial ion channels changed our perception of these double-wrapped organelles from being just the power house of a cell to the guardian of a cell's fate. Mitochondria communicate with the cell through these special channels. Most of the time, the message is encoded by ion flow across the mitochondrial outer and inner membranes. Potassium, sodium, calcium, protons, nucleotides, and proteins traverse the mitochondrial membranes in an exquisitely regulated manner to control a myriad of processes, from respiration and mitochondrial morphology to cell proliferation and cell death. This review is an update on both well established and putative mitochondrial channels regarding their composition, function, regulation, and therapeutic potential.
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Affiliation(s)
| | - Shin-Young Ryu
- New York University College of Dentistry, New York, NY, 10002
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Sommer P, Cowen RL, Berry A, Cookson A, Telfer BA, Williams KJ, Stratford IJ, Kay P, White A, Ray DW. Glucocorticoid receptor over-expression promotes human small cell lung cancer apoptosis in vivo and thereby slows tumor growth. Endocr Relat Cancer 2010; 17:203-13. [PMID: 20015838 PMCID: PMC2828806 DOI: 10.1677/erc-09-0241] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Small cell lung cancer (SCLC) is an aggressive tumor, associated with ectopic ACTH syndrome. We have shown that SCLC cells are glucocorticoid receptor (GR) deficient, and that restoration of GR expression confers glucocorticoid sensitivity and induces apoptosis in vitro. To determine the effects of GR expression in vivo, we characterized a mouse SCLC xenograft model that secretes ACTH precursor peptides, and so drives high circulating corticosterone concentrations (analogous to the ectopic ACTH syndrome). Infection of SCLC xenografts with GR-expressing adenovirus significantly slowed tumor growth compared with control virus infection. Time to fourfold initial tumor volume increased from a median of 9 days to 16 days (P=0.05; n=7 per group). Post-mortem analysis of GR-expressing tumors revealed a threefold increase in apoptotic (TUNEL positive) cells (P<0.01). Infection with the GR-expressing adenovirus caused a significant reduction in Bcl-2 and Bcl-xL transcripts. Furthermore, in both the GR-expressing adenovirus-infected cells and tumors, a significant number of uninfected cells underwent apoptosis, supporting a bystander cell killing effect. Therefore, GR expression is pro-apoptotic for human SCLCs in vivo, as well as in vitro, suggesting that loss of GR confers a survival advantage to SCLCs.
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Affiliation(s)
| | - Rachel L Cowen
- School of Pharmacy and Pharmaceutical SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Andrew Berry
- Endocrine Sciences Research GroupUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Ann Cookson
- Endocrine Sciences Research GroupUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Brian A Telfer
- School of Pharmacy and Pharmaceutical SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Kaye J Williams
- School of Pharmacy and Pharmaceutical SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Ian J Stratford
- School of Pharmacy and Pharmaceutical SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Paul Kay
- Endocrine Sciences Research GroupUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
| | - Anne White
- Endocrine Sciences Research GroupUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
- Faculty of Medical and Human SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
- (Correspondence should be addressed to D W Ray; ; A White; )
| | - David W Ray
- Endocrine Sciences Research GroupUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
- Faculty of Medical and Human SciencesUniversity of ManchesterAV Hill Building, Manchester, M13 9PTUK
- (Correspondence should be addressed to D W Ray; ; A White; )
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Dejean LM, Ryu SY, Martinez-Caballero S, Teijido O, Peixoto PM, Kinnally KW. MAC and Bcl-2 family proteins conspire in a deadly plot. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1231-8. [PMID: 20083086 DOI: 10.1016/j.bbabio.2010.01.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 01/06/2010] [Accepted: 01/09/2010] [Indexed: 12/31/2022]
Abstract
Apoptosis is an elemental form of programmed cell death; it is fundamental to higher eukaryotes and essential to mechanisms controlling tissue homeostasis. Apoptosis is also involved in many pathologies including cancer, neurodegenerative diseases, aging, and infarcts. This cell death program is tightly regulated by Bcl-2 family proteins by controlling the formation of the mitochondrial apoptosis-induced channel or MAC. Assembly of MAC corresponds to permeabilization of the mitochondrial outer membrane, which is the so called commitment step of apoptosis. MAC provides the pathway through the mitochondrial outer membrane for the release of cytochrome c and other pro-apoptotic factors from the intermembrane space. While overexpression of anti-apoptotic Bcl-2 eliminates MAC activity, oligomers of the pro-apoptotic members Bax and/or Bak are essential structural component(s) of MAC. Assembly of MAC from Bax or Bak was monitored in real time by directly patch-clamping mitochondria with micropipettes containing the sentinel tBid, a direct activator of Bax and Bak. Herein, a variety of high affinity inhibitors of MAC (iMAC) that may prove to be crucial tools in mechanistic studies have recently been identified. This review focuses on characterization of MAC activity, its regulation by Bcl-2 family proteins, and a discussion of how MAC can be pharmacologically turned on or off depending on the pathology to be treated.
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Affiliation(s)
- Laurent M Dejean
- Department Basic Sci., 345 East 24th St., New York University, College of Dentistry, New York, NY 10010, USA
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