Caveolin-1 and caveolin-3 form heterooligomeric complexes in atrial cardiac myocytes that are required for doxorubicin-induced apoptosis

Caveolae are 50- to 100-nm invaginations of the plasma membrane. Caveolins are the structural protein components of caveolar membranes. The caveolin gene family is composed of three members: caveolin-1, caveolin-2, and caveolin-3. Caveolin-1 and caveolin-2 are coexpressed in many cell types, including adipocytes, endothelial cells, epithelial cells, and fibroblasts. In contrast, caveolin-3 expression is essentially restricted to skeletal and smooth muscle cells as well as cardiac myocytes. While the interaction between caveolin-1 and caveolin-2 has been documented previously, the reciprocal interaction between endogenous caveolin-1 and caveolin-3 and their functional role in cell types expressing both isoforms have yet to be identified. Here we demonstrate for the first time that caveolin-1 and caveolin-3 are coexpressed in mouse and rat cardiac myocytes of the atria but not ventricles. We also found that caveolin-1 and caveolin-3 can interact and form heterooligomeric complexes in this cell type. Doxorubicin is an effective anticancer agent, but its use is limited by the possible development of cardiotoxicity. Using caveolin-1- and caveolin-3-null mice, we show that both caveolin-1 and caveolin-3 expression are required for doxorubicin-induced apoptosis in the atria through activation of caspase 3. Together, these results bring new insight into the functional role of caveolae and suggest that caveolin-1/caveolin-3 heterooligomeric complexes may play a key role in chemotherapy-induced cardiotoxicity in the atria.

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Interactome Analysis of KIN (Kin17) Shows New Functions of This Protein

Current Issues in Molecular Biology ◽

10.3390/cimb43020056 ◽

2021 ◽

Vol 43 (2) ◽

pp. 767-781

Author(s):

Vanessa Pinatto Gaspar ◽

Anelise Cardoso Ramos ◽

Philippe Cloutier ◽

José Renato Pattaro Junior ◽

Francisco Ferreira Duarte Junior ◽

...

Keyword(s):

Dna Replication ◽

Protein Interactions ◽

Ribosome Biogenesis ◽

Cell Metabolism ◽

Cell Types ◽

Protein Protein Interactions ◽

Cellular Mechanisms ◽

Cancerous Cell ◽

First Time

KIN (Kin17) protein is overexpressed in a number of cancerous cell lines, and is therefore considered a possible cancer biomarker. It is a well-conserved protein across eukaryotes and is ubiquitously expressed in all cell types studied, suggesting an important role in the maintenance of basic cellular function which is yet to be well determined. Early studies on KIN suggested that this nuclear protein plays a role in cellular mechanisms such as DNA replication and/or repair; however, its association with chromatin depends on its methylation state. In order to provide a better understanding of the cellular role of this protein, we investigated its interactome by proximity-dependent biotin identification coupled to mass spectrometry (BioID-MS), used for identification of protein–protein interactions. Our analyses detected interaction with a novel set of proteins and reinforced previous observations linking KIN to factors involved in RNA processing, notably pre-mRNA splicing and ribosome biogenesis. However, little evidence supports that this protein is directly coupled to DNA replication and/or repair processes, as previously suggested. Furthermore, a novel interaction was observed with PRMT7 (protein arginine methyltransferase 7) and we demonstrated that KIN is modified by this enzyme. This interactome analysis indicates that KIN is associated with several cell metabolism functions, and shows for the first time an association with ribosome biogenesis, suggesting that KIN is likely a moonlight protein.

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Tumor Suppressive Role of miR-342-5p in Human Chondrosarcoma Cells and 3D Organoids

International Journal of Molecular Sciences ◽

10.3390/ijms22115590 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5590

Author(s):

Clément Veys ◽

Abderrahim Benmoussa ◽

Romain Contentin ◽

Amandine Duchemin ◽

Emilie Brotin ◽

...

Keyword(s):

Luciferase Reporter ◽

Functional Screening ◽

Western Blots ◽

Egfr Expression ◽

Reporter Assays ◽

Direct Target ◽

Induced Apoptosis ◽

First Time

Chondrosarcomas are malignant bone tumors. Their abundant cartilage-like extracellular matrix and their hypoxic microenvironment contribute to their resistance to chemotherapy and radiotherapy, and no effective therapy is currently available. MicroRNAs (miRNAs) may be an interesting alternative in the development of therapeutic options. Here, for the first time in chondrosarcoma cells, we carried out high-throughput functional screening using impedancemetry, and identified five miRNAs with potential antiproliferative or chemosensitive effects on SW1353 chondrosarcoma cells. The cytotoxic effects of miR-342-5p and miR-491-5p were confirmed on three chondrosarcoma cell lines, using functional validation under normoxia and hypoxia. Both miRNAs induced apoptosis and miR-342-5p also induced autophagy. Western blots and luciferase reporter assays identified for the first time Bcl-2 as a direct target of miR-342-5p, and also Bcl-xL as a direct target of both miR-342-5p and miR-491-5p in chondrosarcoma cells. MiR-491-5p also inhibited EGFR expression. Finally, only miR-342-5p induced cell death on a relevant 3D chondrosarcoma organoid model under hypoxia that mimics the in vivo microenvironment. Altogether, our results revealed the tumor suppressive activity of miR-342-5p, and to a lesser extent of miR-491-5p, on chondrosarcoma lines. Through this study, we also confirmed the potential of Bcl-2 family members as therapeutic targets in chondrosarcomas.

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Glucose Uptake and Glycolysis Reduce Hypoxia-induced Apoptosis in Cultured Neonatal Rat Cardiac Myocytes

Journal of Biological Chemistry ◽

10.1074/jbc.274.18.12567 ◽

1999 ◽

Vol 274 (18) ◽

pp. 12567-12575 ◽

Cited By ~ 153

Author(s):

Ricky Malhotra ◽

Frank C. Brosius

Keyword(s):

Glucose Uptake ◽

Cardiac Myocytes ◽

Neonatal Rat ◽

Neonatal Rat Cardiac Myocytes ◽

Induced Apoptosis ◽

Rat Cardiac Myocytes

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L‐carnitine prevents doxorubicin‐induced apoptosis of cardiac myocytes: role of inhibition of ceramide generation

The FASEB Journal ◽

10.1096/fasebj.13.12.1501 ◽

1999 ◽

Vol 13 (12) ◽

pp. 1501-1510 ◽

Cited By ~ 115

Author(s):

Nathalie Andrieu‐Abadie ◽

Jean‐Pierre Jaffrézou ◽

Stéphane Hatem ◽

Guy Laurent ◽

Thierry Levade ◽

...

Keyword(s):

Cardiac Myocytes ◽

Induced Apoptosis ◽

Ceramide Generation

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Dengue activates mTORC2 signaling to counteract apoptosis and maximize viral replication

10.1101/2020.09.22.308890 ◽

2020 ◽

Author(s):

Christoph C. Carter ◽

Jean Paul Olivier ◽

Alexis Kaushansky ◽

Fred D. Mast ◽

John D. Aitchison

Keyword(s):

Viral Replication ◽

Cell Survival ◽

Structural Protein ◽

Protein Protein Interaction ◽

Mechanistic Target Of Rapamycin ◽

Promote Cell Survival ◽

Important Regulator ◽

Infected Cells ◽

Induced Apoptosis

ABSTRACTThe mechanistic target of rapamycin (mTOR) functions in at least two distinct complexes: mTORC1, which regulates cellular anabolic-catabolic homeostasis, and mTORC2, which is an important regulator of cell survival and cytoskeletal maintenance. mTORC1 has been implicated in the pathogenesis of flaviviruses including dengue, where it contributes to the establishment of a pro-viral autophagic state. In contrast, the role of mTORC2 in viral pathogenesis is unknown. In this study, we explore the consequences of a physical protein-protein interaction between dengue non-structural protein 5 (NS5) and host cell mTOR proteins during infection. Using shRNA to differentially target mTORC1 and mTORC2 complexes, we show that mTORC2 is required for optimal dengue replication. Furthermore, we show that mTORC2 is activated during viral replication, and that mTORC2 counteracts virus-induced apoptosis, promoting the survival of infected cells. This work reveals a novel mechanism by which the dengue flavivirus can promote cell survival to maximize viral replication.

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Role of mitochondrial glucocorticoid receptor in glucocorticoid-induced apoptosis

Journal of Experimental Medicine ◽

10.1084/jem.20050433 ◽

2006 ◽

Vol 203 (1) ◽

pp. 189-201 ◽

Cited By ~ 87

Author(s):

Ronit Vogt Sionov ◽

Orly Cohen ◽

Shlomit Kfir ◽

Yael Zilberman ◽

Eitan Yefenof

Keyword(s):

T Cell ◽

Glucocorticoid Receptor ◽

Cell Lines ◽

Cell Types ◽

Thymic Epithelial Cells ◽

Dependent Manner ◽

Localization Signal ◽

Induced Apoptosis ◽

T Cell Lines

The mechanisms by which glucocorticoid receptor (GR) mediates glucocorticoid (GC)-induced apoptosis are unknown. We studied the role of mitochondrial GR in this process. Dexamethasone induces GR translocation to the mitochondria in GC-sensitive, but not in GC-resistant, T cell lines. In contrast, nuclear GR translocation occurs in all cell types. Thymic epithelial cells, which cause apoptosis of the PD1.6 T cell line in a GR-dependent manner, induce GR translocation to the mitochondria, but not to the nucleus, suggesting a role for mitochondrial GR in eliciting apoptosis. This hypothesis is corroborated by the finding that a GR variant exclusively expressed in the mitochondria elicits apoptosis of several cancer cell lines. A putative mitochondrial localization signal was defined to amino acids 558–580 of human GR, which lies within the NH2-terminal part of the ligand-binding domain. Altogether, our data show that mitochondrial and nuclear translocations of GR are differentially regulated, and that mitochondrial GR translocation correlates with susceptibility to GC-induced apoptosis.

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Role of intracellular SOD in oxidant-induced injury to normal and copper-deficient cardiac myocytes

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.268.3.h1115 ◽

1995 ◽

Vol 268 (3) ◽

pp. H1115-H1121 ◽

Cited By ~ 1

Author(s):

N. Sarvazyan ◽

A. Askari ◽

L. M. Klevay ◽

A. Askari ◽

W. H. Huang

Keyword(s):

Cardiac Myocytes ◽

Copper Deficiency ◽

Atp Content ◽

Sod Activity ◽

Defensive Role ◽

Chronic Oxidative Stress ◽

Adult Cardiac Myocytes ◽

Extracellular Glucose ◽

Rat Cardiac Myocytes

Previous studies have shown that susceptibilities of hepatocytes and endothelial cells to H2O(2)-induced injury are altered by changes in the intracellular activity of Cu,Zn-containing superoxide dismutase (CuZn-SOD). To evaluate the role of intracellular CuZn-SOD in oxidant-induced injury to rat cardiac myocytes, cells with reduced CuZn-SOD activity but normal ATP content were either isolated from the hearts of adult copper-deficient rats or obtained by treatment of normal isolated adult myocytes with diethyldithiocarbamate. These myocytes and controls with normal CuZn-SOD activity were exposed to either reagent H2O2 or oxidants generated by extracellular glucose oxidase plus glucose or xanthine oxidase plus xanthine. It was shown that myocytes with CuZn-SOD activities reduced by 70-90% were equally susceptible to H2O2 and the two oxidant-generating systems as the control myocytes. The findings suggest that in adult cardiac myocytes, in contrast to the situation in some other cells, intracellular CuZn-SOD may not have a significant defensive role against acute H2O(2)-induced injury. The possibility remains, however, that changes in the activity of this enzyme, e.g., in copper deficiency, may be relevant to the ability of myocytes to cope with chronic oxidative stress resulting from imbalance between intracellular oxygen radical-generating and -scavenging systems.

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Attenuation of apoptosis in enterocytes by blockade of potassium channels

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00001.2005 ◽

2005 ◽

Vol 289 (5) ◽

pp. G815-G821 ◽

Cited By ~ 16

Author(s):

Anatoly Grishin ◽

Henri Ford ◽

Jin Wang ◽

Hui Li ◽

Vicenta Salvador-Recatala ◽

...

Keyword(s):

Apoptotic Cell ◽

Cell Loss ◽

Cell Types ◽

Epithelial Cell Line ◽

Channel Blockers ◽

Pharmacological Prevention ◽

Pharmacological Blockade ◽

Inflammatory Bowel ◽

First Time

Apoptosis plays an important role in maintaining the balance between proliferation and cell loss in the intestinal epithelium. Apoptosis rates may increase in intestinal pathologies such as inflammatory bowel disease and necrotizing enterocolitis, suggesting pharmacological prevention of apoptosis as a therapy for these conditions. Here, we explore the feasibility of this approach using the rat epithelial cell line IEC-6 as a model. On the basis of the known role of K+ efflux in apoptosis in various cell types, we hypothesized that K+ efflux is essential for apoptosis in enterocytes and that pharmacological blockade of this efflux would inhibit apoptosis. By probing intracellular [K+] with the K+-sensitive fluorescent dye and measuring the efflux of 86Rb+, we found that apoptosis-inducing treatment with the proteasome inhibitor MG-132 leads to a twofold increase in K+ efflux from IEC-6 cells. Blockade of K+ efflux with tetraethylammonium, 4-aminopyridine, stromatoxin, chromanol 293B, and the recently described K+ channel inhibitor 48F10 prevents DNA fragmentation, caspase activation, release of cytochrome c from mitochondria, and loss of mitochondrial membrane potential. Thus K+ efflux occurs early in the apoptotic program and is required for the execution of later events. Apoptotic K+ efflux critically depends on activation of p38 MAPK. These results demonstrate for the first time the requirement of K+ channel-mediated K+ efflux for progression of apoptosis in enterocytes and suggest the use of K+ channel blockers to prevent apoptotic cell loss occurring in intestinal pathologies.

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