Chemical, physical and biological triggers of evolutionary conserved Bcl-xL-mediated apoptosis

ABSTRACTThe evidence that pan-Bcl-2 or Bcl-xL-specific inhibitors prematurely kill virus-infected or RNA/DNA-transfected cells provides rationale for investigating these apoptotic inducers further. Here, we show that Bcl-xL-specific agent A-1155463 prematurely kills cells of different origins and the small roundworms (C. elegans), when combined with DNA-damaging agent 4-nitroquinoline-1-oxide (4NQO). The synergistic effect of 4NQO-A-1155463 combination was p53-dependent, was associated with the release of Bad and Bax from Bcl-xL, which triggered mitochondrial outer membrane permeabilization (MOMP). Combinations of Bcl-xL-specific inhibitors with certain anticancer compounds or physical insults also killed cells. Collectively, our results suggest that biological, chemical and physical factors trigger evolutionary conserved Bcl-xL-mediated apoptotic pathway.

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Chemical, Physical and Biological Triggers of Evolutionary Conserved Bcl-xL-Mediated Apoptosis

Cancers ◽

10.3390/cancers12061694 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1694 ◽

Cited By ~ 1

Author(s):

Aleksandr Ianevski ◽

Evgeny Kulesskiy ◽

Klara Krpina ◽

Guofeng Lou ◽

Yahyah Aman ◽

...

Keyword(s):

Specific Inhibitor ◽

Chemical Compounds ◽

Mitochondrial Outer Membrane ◽

Physical Factors ◽

Apoptotic Pathway ◽

C Elegans ◽

Mitochondrial Outer Membrane Permeabilization ◽

Evolutionarily Conserved ◽

Novel Drug ◽

Specific Inhibitors

Background: The evidence that pan-Bcl-2 or Bcl-xL-specific inhibitors prematurely kill virus-infected or RNA/DNA-transfected cells provides rationale for investigating these apoptotic inducers further. We hypothesized that not only invasive RNA or DNA (biological factors) but also DNA/RNA-damaging chemical or physical factors could trigger apoptosis that have been sensitized with pan-Bcl-2 or Bcl-xL-specific agents; Methods: We tested chemical and physical factors plus Bcl-xL-specific inhibitor A-1155463 in cells of various origins and the small roundworms (C. elegans); Results: We show that combination of a A-1155463 along with a DNA-damaging agent, 4-nitroquinoline-1-oxide (4NQO), prematurely kills cells of various origins as well as C. elegans. The synergistic effect is p53-dependent and associated with the release of Bad and Bax from Bcl-xL, which trigger mitochondrial outer membrane permeabilization. Furthermore, we found that combining Bcl-xL-specific inhibitors with various chemical compounds or physical insults also induced cell death; Conclusions: Thus, we were able to identify several biological, chemical and physical triggers of the evolutionarily conserved Bcl-xL-mediated apoptotic pathway, shedding light on strategies and targets for novel drug development.

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Mitochondria in cell death

Essays in Biochemistry ◽

10.1042/bse0470099 ◽

2010 ◽

Vol 47 ◽

pp. 99-114 ◽

Cited By ~ 91

Author(s):

Melissa J. Parsons ◽

Douglas R. Green

Keyword(s):

Cell Death ◽

Neurological Diseases ◽

Mitochondrial Outer Membrane ◽

Intermembrane Space ◽

Apoptotic Pathway ◽

Life And Death ◽

Mitochondrial Outer Membrane Permeabilization ◽

Mitochondrial Functions ◽

A Cell ◽

Signalling Cascade

Apoptosis can be thought of as a signalling cascade that results in the death of the cell. Properly executed apoptosis is critically important for both development and homoeostasis of most animals. Accordingly, defects in apoptosis can contribute to the development of autoimmune disorders, neurological diseases and cancer. Broadly speaking, there are two main pathways by which a cell can engage apoptosis: the extrinsic apoptotic pathway and the intrinsic apoptotic pathway. At the centre of the intrinsic apoptotic signalling pathway lies the mitochondrion, which, in addition to its role as the bioenergetic centre of the cell, is also the cell’s reservoir of pro-death factors which reside in the mitochondrial IMS (intermembrane space). During intrinsic apoptosis, pores are formed in the OMM (outer mitochondrial membrane) of the mitochondria in a process termed MOMP (mitochondrial outer membrane permeabilization). This allows for the release of IMS proteins; once released during MOMP, some IMS proteins, notably cytochrome c and Smac/DIABLO (Second mitochondria-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low pI), promote caspase activation and subsequent cleavage of structural and regulatory proteins in the cytoplasm and the nucleus, leading to the demise of the cell. MOMP is achieved through the co-ordinated actions of pro-apoptotic members and inhibited by anti-apoptotic members of the Bcl-2 family of proteins. Other aspects of mitochondrial physiology, such as mitochondrial bioenergetics and dynamics, are also involved in processes of cell death that proceed through the mitochondria. Proper regulation of these mitochondrial functions is vitally important for the life and death of the cell and for the organism as a whole.

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The pharmalogical reactivation of p53 function improves breast tumor cell lysis by granzyme B and NK cells through induction of autophagy

Cell Death and Disease ◽

10.1038/s41419-019-1950-1 ◽

2019 ◽

Vol 10 (10) ◽

Cited By ~ 7

Author(s):

Marie Chollat-Namy ◽

Thouraya Ben Safta-Saadoun ◽

Djazia Haferssas ◽

Guillaume Meurice ◽

Salem Chouaib ◽

...

Keyword(s):

Breast Cancer ◽

Nk Cells ◽

Tumor Cells ◽

Nk Cell ◽

P53 Protein ◽

Granzyme B ◽

Mitochondrial Outer Membrane ◽

Cytotoxic Lymphocyte ◽

Apoptotic Pathway ◽

Mitochondrial Outer Membrane Permeabilization

Abstract Cytotoxic T lymphocytes (CTL) and natural killer cells (NK)-mediated elimination of tumor cells is mostly dependent on Granzyme B apoptotic pathway, which is regulated by the wild type (wt) p53 protein. Because TP53 inactivating mutations, frequently found in human tumors, could interfere with Granzyme B-mediated cell death, the use of small molecules developed to reactivate wtp53 function in p53-mutated tumor cells could optimize their lysis by CTL or NK cells. Here, we show that the pharmalogical reactivation of a wt-like p53 function in p53-mutated breast cancer cells using the small molecule CP-31398 increases their sensitivity to NK-mediated lysis. This potentiation is dependent on p53-mediated induction of autophagy via the sestrin-AMPK-mTOR pathway and the ULK axis. This CP31398-induced autophagy sequestrates in autophagosomes several anti-apoptotic proteins, including Bcl-XL and XIAP, facilitating Granzyme B-mediated mitochondrial outer membrane permeabilization, caspase-3 activation and Granzyme B- or NK cell-induced apoptosis. Together, our results define a new way to increase cytotoxic lymphocyte-mediated lysis of p53-mutated breast cancer cell, through a p53-dependent autophagy induction, with potential applications in combined immunotherapeutic approaches.

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ER shaping proteins regulate mitochondrial fission, outer membrane permeabilization and apoptosis

10.1101/340448 ◽

2018 ◽

Cited By ~ 1

Author(s):

Mateus Milani ◽

Gerald M Cohen ◽

Shankar Varadarajan

Keyword(s):

Outer Membrane ◽

Structural Integrity ◽

Mitochondrial Fission ◽

Membrane Dynamics ◽

Membrane Permeabilization ◽

Mitochondrial Outer Membrane ◽

Caspase Activation ◽

Apoptotic Pathway ◽

Mitochondrial Outer Membrane Permeabilization

AbstractThe mitochondrial fission machinery, comprising a dynamin-related GTPase, DRP-1, is crucial for the regulation of mitochondrial membrane dynamics. Recent reports suggest that the tubular architecture of the endoplasmic reticulum (ER) marks the constriction sites on the mitochondria to facilitate DRP-1-mediated mitochondrial fission. However, the role of several ER shaping proteins that maintain the elaborate network of tubes and sheets in mitochondrial constriction and fission is not yet known. In this report, we demonstrate that modulation of the expression levels of key ER shaping proteins, namely Reticulon1 (RTN-1), Reticulon 4 (RTN-4), Lunapark-1 (LNP-1) and CLIMP-63, markedly decreased the extent of mitochondrial fission mediated by BH3 mimetics, despite no detectable changes in DRP-1 recruitment to the mitochondria. Furthermore, modulation of ER shaping proteins significantly decreased other hallmarks of apoptosis, such as mitochondrial outer membrane permeabilization, caspase activation and phosphatidylserine externalization, and functioned independently of mitochondrial cristae remodeling, thus demonstrating a requirement of ER shaping proteins and ER structural integrity for the efficient execution of the instrinsic apoptotic pathway.

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Mitochondrial outer membrane permeabilization at the single molecule level

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03771-4 ◽

2021 ◽

Author(s):

Shashank Dadsena ◽

Andreas Jenner ◽

Ana J. García-Sáez

Keyword(s):

Cell Death ◽

Outer Membrane ◽

Single Molecule ◽

Apoptotic Cell ◽

Interaction Network ◽

Regulatory Elements ◽

Membrane Permeabilization ◽

Mitochondrial Outer Membrane ◽

Apoptotic Pathway ◽

Mitochondrial Outer Membrane Permeabilization

AbstractApoptotic cell death is essential for development, immune function or tissue homeostasis, and its mis-regulation is linked to various diseases. Mitochondrial outer membrane permeabilization (MOMP) is a central event in the intrinsic apoptotic pathway and essential to control the execution of cell death. Here we review current concepts in regulation of MOMP focusing on the interaction network of the Bcl-2 family proteins as well as further regulatory elements influencing MOMP. As MOMP is a complex spatially and temporally controlled process, we point out the importance of single-molecule techniques to unveil processes which would be masked by ensemble measurements. We report key single-molecule studies applied to decipher the composition, assembly mechanism and structure of protein complexes involved in MOMP regulation.

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Mitochondrial Outer Membrane Proteins Assist Bid in Bax-mediated Lipidic Pore Formation

Molecular Biology of the Cell ◽

10.1091/mbc.e08-10-1056 ◽

2009 ◽

Vol 20 (8) ◽

pp. 2276-2285 ◽

Cited By ~ 82

Author(s):

Blanca Schafer ◽

Joel Quispe ◽

Vineet Choudhary ◽

Jerry E. Chipuk ◽

Teddy G. Ajero ◽

...

Keyword(s):

Outer Membrane ◽

Pore Formation ◽

Outer Membrane Proteins ◽

Mitochondrial Outer Membrane ◽

Outer Membranes ◽

Mitochondrial Outer Membrane Permeabilization ◽

In Vitro Systems ◽

Large Round ◽

Key Features

Mitochondrial outer membrane permeabilization (MOMP) is a critical step in apoptosis and is regulated by Bcl-2 family proteins. In vitro systems using cardiolipin-containing liposomes have demonstrated the key features of MOMP induced by Bax and cleaved Bid; however, the nature of the “pores” and how they are formed remain obscure. We found that mitochondrial outer membranes contained very little cardiolipin, far less than that required for liposome permeabilization, despite their responsiveness to Bcl-2 family proteins. Strikingly, the incorporation of isolated mitochondrial outer membrane (MOM) proteins into liposomes lacking cardiolipin conferred responsiveness to cleaved Bid and Bax. Cardiolipin dependence was observed only when permeabilization was induced with cleaved Bid but not with Bid or Bim BH3 peptide or oligomerized Bax. Therefore, we conclude that MOM proteins specifically assist cleaved Bid in Bax-mediated permeabilization. Cryoelectron microscopy of cardiolipin-liposomes revealed that cleaved Bid and Bax produced large round holes with diameters of 25–100 nm, suggestive of lipidic pores. In sum, we propose that activated Bax induces lipidic pore formation and that MOM proteins assist cleaved Bid in this process in the absence of cardiolipin.

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Sab concentrations indicate chemotherapeutic susceptibility in ovarian cancer cell lines

Biochemical Journal ◽

10.1042/bcj20180603 ◽

2018 ◽

Vol 475 (21) ◽

pp. 3471-3492 ◽

Cited By ~ 4

Author(s):

Iru Paudel ◽

Sean M. Hernandez ◽

Gilda M. Portalatin ◽

Tara P. Chambers ◽

Jeremy W. Chambers

Keyword(s):

Ovarian Cancer ◽

Cell Lines ◽

Ovarian Cancer Cell ◽

Prognostic Biomarker ◽

Chemotherapeutic Agents ◽

Mitochondrial Outer Membrane ◽

Expression Data ◽

Apoptotic Pathway ◽

Gynecological Malignancy ◽

Ovarian Cancer Cell Lines

The occurrence of chemotherapy-resistant tumors makes ovarian cancer (OC) the most lethal gynecological malignancy. While many factors may contribute to chemoresistance, the mechanisms responsible for regulating tumor vulnerability are under investigation. Our analysis of gene expression data revealed that Sab, a mitochondrial outer membrane (MOM) scaffold protein, was down-regulated in OC patients. Sab-mediated signaling induces cell death, suggesting that this apoptotic pathway is diminished in OC. We examined Sab expression in a panel of OC cell lines and found that the magnitude of Sab expression correlated to chemo-responsiveness; wherein, OC cells with low Sab levels were chemoresistant. The Sab levels were reflected by a corresponding amount of stress-induced c-Jun N-terminal kinase (JNK) on the MOM. BH3 profiling and examination of Bcl-2 and BH3-only protein concentrations revealed that cells with high Sab concentrations were primed for apoptosis, as determined by the decrease in pro-survival Bcl-2 proteins and an increase in pro-apoptotic BH3-only proteins on mitochondria. Furthermore, overexpression of Sab in chemoresistant cells enhanced apoptotic priming and restored cellular vulnerability to a combination treatment of cisplatin and paclitaxel. Contrariwise, inhibiting Sab-mediated signaling or silencing Sab expression in a chemosensitive cell line resulted in decreased apoptotic priming and increased resistance. The effects of silencing on Sab on the resistance to chemotherapeutic agents were emulated by the silencing or inhibition of JNK, which could be attributed to changes in Bcl-2 protein concentrations induced by sub-chronic JNK inhibition. We propose that Sab may be a prognostic biomarker to discern personalized treatments for OC patients.

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