scholarly journals MiT/TFE family members suppress L-leucyl–L-leucine methyl ester-induced cell death

2021 ◽  
Vol 46 (3) ◽  
pp. 143-156
Author(s):  
Ayaka Yabuki ◽  
Masatsugu Miyara ◽  
Kanae Umeda-Miyara ◽  
Saya Takao ◽  
Seigo Sanoh ◽  
...  
2000 ◽  
Vol 20 (9) ◽  
pp. 3125-3136 ◽  
Author(s):  
Atan Gross ◽  
Kirsten Pilcher ◽  
Elizabeth Blachly-Dyson ◽  
Emy Basso ◽  
Jennifer Jockel ◽  
...  

ABSTRACT The BCL-2 family includes both proapoptotic (e.g., BAX and BAK) and antiapoptotic (e.g., BCL-2 and BCL-XL) molecules. The cell death-regulating activity of BCL-2 members appears to depend on their ability to modulate mitochondrial function, which may include regulation of the mitochondrial permeability transition pore (PTP). We examined the function of BAX and BCL-XL using genetic and biochemical approaches in budding yeast because studies with yeast suggest that BCL-2 family members act upon highly conserved mitochondrial components. In this study we found that in wild-type yeast, BAX induced hyperpolarization of mitochondria, production of reactive oxygen species, growth arrest, and cell death; however, cytochrome c was not released detectably despite the induction of mitochondrial dysfunction. Coexpression of BCL-XL prevented all BAX-mediated responses. We also assessed the function of BCL-XL and BAX in the same strain of Saccharomyces cerevisiae with deletions of selected mitochondrial proteins that have been implicated in the function of BCL-2 family members. BAX-induced growth arrest was independent of the tested mitochondrial components, including voltage-dependent anion channel (VDAC), the catalytic β subunit or the δ subunit of the F0F1-ATP synthase, mitochondrial cyclophilin, cytochrome c, and proteins encoded by the mitochondrial genome as revealed by [rho 0] cells. In contrast, actual cell killing was dependent upon select mitochondrial components including the β subunit of ATP synthase and mitochondrial genome-encoded proteins but not VDAC. The BCL-XL protection from either BAX-induced growth arrest or cell killing proved to be independent of mitochondrial components. Thus, BAX induces two cellular processes in yeast which can each be abrogated by BCL-XL: cell arrest, which does not require aspects of mitochondrial biochemistry, and cell killing, which does.


2002 ◽  
Vol 22 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Yoshihide Tsujimoto

An increase in the permeability of outer mitochondrial membrane is central to apoptotic cell death, and results in the release of several apoptogenic factors such as cytochrome c into the cytoplasm to activate downstream destructive programs. The voltage-dependent anion channel (VDAC or mitochondrial porin) plays an essential role in disrupting the mitochondrial membrane barrier and is regulated directly by members of the Bcl-2 family proteins. Anti-apoptotic Bcl-2 family members interact with and close the VDAC, whereas some, but not all, proapoptotic members interact with VDAC to open protein-conducting pore through which apoptogenic factors pass. Although the VDAC is involved directly in breaking the mitochondrial membrane barrier and is a known component of the permeability transition pore complex, VDAC-dependent increase in outer membrane permeability can be independent of the permeability transition event such as mitochondrial swelling followed by rupture of the outer mitochondrial membrane. VDAC interacts not only with Bcl-2 family members but also with proteins such as gelsolin, an actin regulatory protein, and appears to be a convergence point for a variety of cell survival and cell death signals.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 35-36
Author(s):  
Stephen Jun Fei Chong ◽  
Mary C Collins ◽  
Liam Hackett ◽  
Matthew S. Davids

Introduction Resistance to apoptosis is a hallmark of cancer, and modulation of BCL-2 family proteins is an important mediator of such resistance in hematologic malignancies. Despite the clinical efficacy of the BCL-2 inhibitor venetoclax (VEN), prolonged treatment may lead to resistance, such as the BCL2 G101V mutation (Blombery et al, Blood, 2020); however, over half of VEN resistant cases are not explained by known genetic mechanisms. Phosphorylation of BCL-2 at serine-70 (S70pBCL2) or of MCL-1 at threonine-163 (T163pMCL1) have been shown to increase sequestration of the pro-apoptotic protein BAX (Deng et al, JNCI, 2000) and stabilize the level of anti-apoptotic protein MCL-1 (Wang et al, Mol Cancer, 2014), respectively. We hypothesized that the increase in post-translational modifications of BCL-2 family members, in particular S70pBCL2 and T163pMCL1, are novel mechanisms of functional VEN resistance in lymphoid malignancies. We further hypothesized that the FDA-approved phosphatase activator drug FTY720 (fingolimod) would de-phosphorylate these BCL-2 family members and thereby re-sensitize malignant lymphoid cells to VEN-induced apoptosis. Methods A VEN resistant diffuse large B-cell lymphoma cell line (OCI-Ly1-R) as well as peripheral blood mononuclear cells from 12 previously untreated CLL patients co-cultured with human stromal NK-Tert cells were treated ex vivo with VEN +/- FTY720. A VEN sensitive cell line (OCI-Ly1-S) was treated with VEN +/- a phosphatase inhibitor okadaic acid (OA). Western blot was used to evaluate changes in S70pBCL2 and T163pMCL1 protein levels. BH3 profiling via flow cytometry was performed to determine the survival dependence on anti-apoptotic BCL-2 family members via cytochrome c release in response to specific BH3-only peptides and drugs such as VEN applied directly to mitochondria (Ryan et al, Biol Chem, 2016). Cell viability assays (CellTiter-Glo, Trypan Blue and Annexin/Hoechst) were employed to investigate the effects of FTY720 on OCI-Ly1-R resistance to VEN. The BCL-2-BAX interaction was investigated using co-immunoprecipitation in VEN resistant and sensitive cells following treatment with VEN +/- FTY720. T-test, ANOVA and multiple comparison with a statistical significance set at 2-tailed p ≤ 0.05 were used. Results OCI-Ly1-R cells displayed higher S70pBCL2, T163pMCL1 and MCL-1 expression compared to OCI-Ly1-S cells. Notably, the increase in S70pBCL2 was associated with reduced response of VEN-mediated BCL-2-BAX dissociation, while the increase in T163pMCL1 was accompanied by enhanced MCL-1 protein expression. Using BH3 profiling, we found that the increase in S70pBCL2, T163pMCL1 and MCL-1 expression were functionally associated with a decrease in BCL-2 survival dependence (-79.1%, 1μM VEN, P < 0.0001) and an increase in MCL-1 dependence (+52%, 10μM MS1, P < 0.0001) (Fig. A). The addition of FTY720 reversed these observations in OCI-Ly1-R cells, where we observed a decrease in S70pBCL2, T163pMCL1 and MCL-1 protein expression, BCL-2 and BAX interaction, as well as a "re-wired" functional dependence toward BCL-2 (-21.6% 10μM MS1, +27.9% 1μM VEN, P < 0.0001) (Fig. B). Importantly, pre-treatment with FTY720 re-sensitized OCI-Ly1-R cells to VEN-induced cell death (+56.1%, P = 0.0001) (Fig. C). Conversely, treatment with a phosphatase inhibitor, OA, led to an increase in S70pBCL2, T163pMCL1 and MCL-1 expression as well as reduced late death of OCI-Ly1-S cells (-60%, P = 0.0018). We validated our cell line results in primary CLL cells, and again the combination of FTY720 and VEN similarly reduced S70pBCL2, T163pMCL1 and MCL-1 expression, increased BCL-2 dependence, and enhanced VEN-induced cell death (+23.6%, P < 0.0001). Conclusion Increased S70pBCL2 and T163pMCL1 are associated with VEN resistance, in part by inhibiting VEN-induced BCL-2-BAX dissociation and switching the functional survival dependence from BCL-2 to MCL-1. FTY720 re-sensitizes VEN resistant cells by reducing S70pBCL2, T163pMCL1 and MCL-1 expression, dissociating BAX from BCL-2 and "re-wiring" the survival dependence to BCL-2. These preclinical findings support the exploration of this strategy clinically in patients with VEN resistant lymphoid malignancies. Disclosures Davids: Sunesis: Consultancy; AbbVie: Consultancy; Surface Oncology: Research Funding; Genentech: Consultancy, Research Funding; Eli Lilly: Consultancy; Celgene: Consultancy; AstraZeneca: Consultancy, Research Funding; BeiGene: Consultancy; Ascentage Pharma: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy; Pharmacyclics: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Zentalis: Consultancy; Novartis: Consultancy, Research Funding; Gilead Sciences: Consultancy; Bristol Myers Squibb: Research Funding; Janssen: Consultancy; MEI Pharma: Consultancy, Research Funding; Syros Pharmaceuticals: Consultancy; Merck: Consultancy; Research to Practice: Honoraria.


1996 ◽  
Vol 310 (2-3) ◽  
pp. 137-140 ◽  
Author(s):  
C. Charriaut-Marlangue ◽  
I. Margaill ◽  
F. Borrega ◽  
M. Plotkine ◽  
Y. Ben-Ari

FEBS Letters ◽  
2002 ◽  
Vol 525 (1-3) ◽  
pp. 93-99 ◽  
Author(s):  
Sebastian Dietz ◽  
Karen Rother ◽  
Casimir Bamberger ◽  
Hartwig Schmale ◽  
Joachim Mössner ◽  
...  

Blood ◽  
2006 ◽  
Vol 108 (5) ◽  
pp. 1461-1468 ◽  
Author(s):  
Paul G. Ekert ◽  
Anissa M. Jabbour ◽  
Anand Manoharan ◽  
Jacki E. Heraud ◽  
Jai Yu ◽  
...  

Growth and survival of hematopoietic cells is regulated by growth factors and cytokines, such as interleukin 3 (IL-3). When cytokine is removed, cells dependent on IL-3 kill themselves by a mechanism that is inhibited by overexpression of Bcl-2 and is likely to be mediated by proapoptotic Bcl-2 family members. Bad and Bim are 2 such BH3-only Bcl-2 family members that have been implicated as key initiators in apoptosis following growth factor withdrawal, particularly in IL-3-dependent cells. To test the role of Bad, Bim, and other proapoptotic Bcl-2 family members in IL-3 withdrawal-induced apoptosis, we generated IL-3-dependent cell lines from mice lacking the genes for Bad, Bim, Puma, both Bad and Bim, and both Bax and Bak. Surprisingly, Bad was not required for cell death following IL-3 withdrawal, suggesting changes to phosphorylation of Bad play only a minor role in apoptosis in this system. Deletion of Bim also had no effect, but cells lacking Puma survived and formed colonies when IL-3 was restored. Inhibition of the PI3 kinase pathway promoted apoptosis in the presence or absence of IL-3 and did not require Bad, Bim, or Puma, suggesting IL-3 receptor survival signals and PI3 kinase survival signals are independent.


1999 ◽  
Vol 19 (10) ◽  
pp. 6673-6681 ◽  
Author(s):  
Brian S. Chang ◽  
Ameeta Kelekar ◽  
Marian H. Harris ◽  
John E. Harlan ◽  
Stephen W. Fesik ◽  
...  

ABSTRACT bcl-x is a member of the bcl-2 family of genes. The major protein product, Bcl-xL, is a 233-amino-acid protein which has antiapoptotic properties. In contrast, one of the alternatively spliced transcripts of the bcl-xgene codes for the protein Bcl-xS, which lacks 63 amino acids present in Bcl-xL and has proapoptotic activity. Unlike other proapoptotic Bcl-2 family members, such as Bax and Bak, Bcl-xS does not seem to induce cell death in the absence of an additional death signal. However, Bcl-xS does interfere with the ability of Bcl-xL to antagonize Bax-induced death in transiently transfected 293 cells. Mutational analysis of Bcl-xS was conducted to identify the domains necessary to mediate its proapoptotic phenotype. Deletion mutants of Bcl-xS which still contained an intact BH3 domain retained the ability to inhibit survival through antagonism of Bcl-xL. Bcl-xS was able to form heterodimers with Bcl-xL in mammalian cells, and its ability to inhibit survival correlated with the ability to heterodimerize with Bcl-xL. Deletion mutants of Bax and Bcl-2, which lacked BH1 and BH2 domains but contained a BH3 domain, were able to antagonize the survival effect conferred by Bcl-xL. The results suggest that BH3 domains from both pro- and antiapoptotic Bcl-2 family members, while lacking an intrinsic ability to promote programmed cell death, can be potent inhibitors of Bcl-xL survival function.


2017 ◽  
Vol 114 (28) ◽  
pp. 7361-7366 ◽  
Author(s):  
Jae Young Choi ◽  
Qi Qiao ◽  
Se-Hoon Hong ◽  
Chang Min Kim ◽  
Jae-Hee Jeong ◽  
...  

Cell death-inducing DFF45-like effector (CIDE) domains, initially identified in apoptotic nucleases, form a family with diverse functions ranging from cell death to lipid homeostasis. Here we show that the CIDE domains of Drosophila and human apoptotic nucleases Drep2, Drep4, and DFF40 all form head-to-tail helical filaments. Opposing positively and negatively charged interfaces mediate the helical structures, and mutations on these surfaces abolish nuclease activation for apoptotic DNA fragmentation. Conserved filamentous structures are observed in CIDE family members involved in lipid homeostasis, and mutations on the charged interfaces compromise lipid droplet fusion, suggesting that CIDE domains represent a scaffold for higher-order assembly in DNA fragmentation and other biological processes such as lipid homeostasis.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4585-4585
Author(s):  
Christian Scholz ◽  
Antje Richter ◽  
Anja Richter ◽  
Bernd Dörken ◽  
Peter T. Daniel

Abstract Arsenic trioxide (As2O3, arsenite) efficiently kills cells from various hematologic malignancies and has successfully been employed for the treatment of acute promyelocytic leukaemia, myelodysplastic syndrome, and multiple myeloma. Investigating the mechanisms of arsenic trioxide-induced cell death, we recently demonstrated that arsenite-mediated cell demise has a partially necrotic phenotype, occurs independently of the extrinsic death receptor pathway of apoptosis, and is not hampered by the absence of functioning caspases. On the contrary, cell death proceeded entirely via an intrinsic, mitochondrial pathway and was efficiently blocked by the anti-apoptotic Bcl-2 family members Bcl-2 or Bcl-xL. Here, we address the role of the pro-apoptotic multi-domain Bcl-2 family members Bax and Bak. By employing different cell lines deficient for Bax and/or Bak, we demonstrate that Bax- or Bak-deficiency as well as the combined absence only partially blocks arsenite-induced cell death. While the detection of an additive effect of the combined Bax-/Bak-deficiency argues for a non redundant function of Bax and Bak, the persistence of a substantial percentage of arsenite-mediated cell demise in different double deficient cell lines nevertheless suggests a mode of arsenic trioxide-mediated cell death independent from these central inducers of apoptotic cell demise. The presented data add to the notion that arsenic trioxide kills tumor cells independent of the apoptotic machinery, and warrants further investigation on the efficacy of this compound in malignancies with deficiencies of the apoptotic cell death pathways.


2000 ◽  
Vol 148 (4) ◽  
pp. 703-714 ◽  
Author(s):  
Paul A. Colussi ◽  
Leonie M. Quinn ◽  
David C.S. Huang ◽  
Michelle Coombe ◽  
Stuart H. Read ◽  
...  

Bcl-2 family of proteins are key regulators of apoptosis. Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects. Here, we report the identification and characterization of Debcl, the first Bcl-2 homologue in Drosophila melanogaster. Structurally, Debcl is similar to Bax-like proapoptotic Bcl-2 family members. Ectopic expression of Debcl in cultured cells and in transgenic flies causes apoptosis, which is inhibited by coexpression of the baculovirus caspase inhibitor P35, indicating that Debcl is a proapoptotic protein that functions in a caspase-dependent manner. debcl expression correlates with developmental cell death in specific Drosophila tissues. We also show that debcl genetically interacts with diap1 and dark, and that debcl-mediated apoptosis is not affected by gene dosage of rpr, hid, and grim. Biochemically, Debcl can interact with several mammalian and viral prosurvival Bcl-2 family members, but not with the proapoptotic members, suggesting that it may regulate apoptosis by antagonizing prosurvival Bcl-2 proteins. RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos. These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.


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