scholarly journals BimS-induced apoptosis requires mitochondrial localization but not interaction with anti-apoptotic Bcl-2 proteins

2007 ◽  
Vol 177 (4) ◽  
pp. 625-636 ◽  
Author(s):  
Arnim Weber ◽  
Stefan A. Paschen ◽  
Klaus Heger ◽  
Florian Wilfling ◽  
Tobias Frankenberg ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Membrane Insertion ◽  
Apoptosis Induction ◽  
Mitochondrial Targeting ◽  
Mitochondrial Localization ◽  
Mitochondrial Translocation ◽  
Killing Activity ◽  
Regulated Expression ◽  
Direct Binding ◽  
Induced Apoptosis

Release of apoptogenic proteins such as cytochrome c from mitochondria is regulated by pro- and anti-apoptotic Bcl-2 family proteins, with pro-apoptotic BH3-only proteins activating Bax and Bak. Current models assume that apoptosis induction occurs via the binding and inactivation of anti-apoptotic Bcl-2 proteins by BH3-only proteins or by direct binding to Bax. Here, we analyze apoptosis induction by the BH3-only protein BimS. Regulated expression of BimS in epithelial cells was followed by its rapid mitochondrial translocation and mitochondrial membrane insertion in the absence of detectable binding to anti-apoptotic Bcl-2 proteins. This caused mitochondrial recruitment and activation of Bax and apoptosis. Mutational analysis of BimS showed that mitochondrial targeting, but not binding to Bcl-2 or Mcl-1, was required for apoptosis induction. In yeast, BimS enhanced the killing activity of Bax in the absence of anti-apoptotic Bcl-2 proteins. Thus, cell death induction by a BH3-only protein can occur through a process that is independent of anti-apoptotic Bcl-2 proteins but requires mitochondrial targeting.

scholarly journals The Putative Pore-Forming Domain of Bax Regulates Mitochondrial Localization and Interaction with Bcl-XL

2000 ◽  
Vol 20 (5) ◽  
pp. 1604-1615 ◽  
Author(s):  
Shahrzad Nouraini ◽  
Emmanuelle Six ◽  
Shigemi Matsuyama ◽  
Stainslaw Krajewski ◽  
John C. Reed
Keyword(s):  
Mammalian Cells ◽  
Membrane Insertion ◽  
Mitochondrial Targeting ◽  
Mitochondrial Localization ◽  
Gain Of Function ◽  
Bh3 Domain ◽  
Membrane Barrier ◽  
Independent Mechanism ◽  
Site Of Action ◽  
Charged Residues

ABSTRACT Bax is a proapoptotic member of the Bcl-2 family of proteins which localizes to and uses mitochondria as its major site of action. Bax normally resides in the cytoplasm and translocates to mitochondria in response to apoptotic stimuli, and it promotes apoptosis in two ways: (i) by disrupting mitochondrial membrane barrier function by formation of ion-permeable pores in mitochondrial membranes and (ii) by binding to antiapoptotic Bcl-2 family proteins via its BH3 domain and inhibiting their functions. A hairpin pair of amphipathic α-helices (α5-α6) in Bax has been predicted to participate in membrane insertion and pore formation by Bax. We mutagenized several charged residues in the α5-α6 domain of Bax, changing them to alanine. These substitution mutants of Bax constitutively localized to mitochondria and displayed a gain-of-function phenotype when expressed in mammalian cells. Furthermore, substitution of 8 out of 10 charged residues in the α5-α6 domain of Bax resulted in a loss of cytotoxicity in yeast but a gain-of-function phenotype in mammalian cells. The enhanced function of this Bax mutant was correlated with increased binding to Bcl-XL, through a BH3-independent mechanism. These observations reveal new functions for the α5-α6 hairpin loop of Bax: (i) regulation of mitochondrial targeting and (ii) modulation of binding to antiapoptotic Bcl-2 proteins.

scholarly journals Role of NAD(P)H:quinone oxidoreductase (NQO1) in apoptosis induction by aziridinylbenzoquinones RH1 and MeDZQ.

2005 ◽  
Vol 52 (4) ◽  
pp. 937-942 ◽  
Author(s):  
Ausra Nemeikaite-Ceniene ◽  
Aldona Dringeliene ◽  
Jonas Sarlauskas ◽  
Narimantas Cenas
Keyword(s):  
Regression Analysis ◽  
Redox Cycling ◽  
Apoptosis Induction ◽  
Electron Reduction ◽  
Induced Apoptosis ◽  
Phenylene Diamine

We aimed to characterize the role of NAD(P)H:quinone oxidoreductase (NQO1) in apoptosis induction by antitumour quinones RH1 (2,5-diaziridinyl-3-hydroxymethyl-6-methyl-1,4-benzoquinone) and MeDZQ (2,5-dimethyl-3,6-diaziridinyl-1,4-benzoquinone). Digitonin-permeabilized FLK cells catalyzed NADPH-dependent single- and two-electron reduction of RH1 and MeDZQ. At equitoxic concentrations, RH1 and MeDZQ induced apoptosis more efficiently than the nonalkylating duroquinone or H(2)O(2). The antioxidant N,N'-diphenyl-p-phenylene diamine, desferrioxamine, and the inhibitor of NQO1 dicumarol, protected against apoptosis induction by all compounds investigated, but to a different extent. The results of multiparameter regression analysis indicate that RH1 and MeDZQ most likely induce apoptosis via NQO1-linked formation of alkylating species but not via NQO1-linked redox cycling.

scholarly journals Cyclovirobuxine D Induces Apoptosis and Mitochondrial Damage in Glioblastoma Cells Through ROS-Mediated Mitochondrial Translocation of Cofilin

2021 ◽  
Vol 11 ◽  
Author(s):  
Lin Zhang ◽  
Ruoqiu Fu ◽  
Dongyu Duan ◽  
Ziwei Li ◽  
Bin Li ◽  
...  
Keyword(s):  
Cell Lines ◽  
Oxidant Stress ◽  
Mitochondrial Damage ◽  
Dependent Manner ◽  
Mitochondrial Translocation ◽  
Mitochondrial Superoxide ◽  
Human Astrocytes ◽  
Anti Cancer ◽  
Normal Human ◽  
Induced Apoptosis

BackgroundCyclovirobuxine D (CVBD), a steroidal alkaloid, has multiple pharmacological activities, including anti-cancer activity. However, the anti-cancer effect of CVBD on glioblastoma (GBM) has seldom been investigated. This study explores the activity of CVBD in inducing apoptosis of GBM cells, and examines the related mechanism in depth.MethodsGBM cell lines (T98G, U251) and normal human astrocytes (HA) were treated with CVBD. Cell viability was examined by CCK-8 assay, and cell proliferation was evaluated by cell colony formation counts. Apoptosis and mitochondrial superoxide were measured by flow cytometry. All protein expression levels were determined by Western blotting. JC-1 and CM-H2DCFDA probes were used to evaluate the mitochondrial membrane potential (MMP) change and intracellular ROS generation, respectively. The cell ultrastructure was observed by transmission electron microscope (TEM). Colocalization of cofilin and mitochondria were determined by immunofluorescence assay.ResultsCVBD showed a greater anti-proliferation effect on the GBM cell lines, T98G and U251, than normal human astrocytes in dose- and time-dependent manners. CVBD induced apoptosis and mitochondrial damage in GBM cells. We found that CVBD led to mitochondrial translocation of cofilin. Knockdown of cofilin attenuated CVBD-induced apoptosis and mitochondrial damage. Additionally, the generation of ROS and mitochondrial superoxide was also induced by CVBD in a dose-dependent manner. N-acetyl-L-cysteine (NAC) and mitoquinone (MitoQ) pre-treatment reverted CVBD-induced apoptosis and mitochondrial damage. MitoQ pretreatment was able to block the mitochondrial translocation of cofilin caused by CVBD.ConclusionsOur data revealed that CVBD induced apoptosis and mitochondrial damage in GBM cells. The underlying mechanism is related to mitochondrial translocation of cofilin caused by mitochondrial oxidant stress.

scholarly journals PGV-0 AND PGV-1 INCREASED APOPTOSIS INDUCTION OF DOXORUBICIN ON MCF-7 BREAST CANCER CELLS

2015 ◽  
Vol 12 (2) ◽  
pp. 55-59
Author(s):  
Edy Meiyanto
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Chemotherapeutic Agent ◽  
Apoptosis Induction ◽  
Single Treatment ◽  
Cell Cycle Modulation ◽  
Induced Apoptosis ◽  
Mcf 7

As chemotherapeutic backbone for breast cancer therapy, doxorubicin showed various side effects and induced resistancy of breast cancer cells. Development of targeted therapy on breast cancer focused on combinatorial therapy of doxorubicin and molecular targeted agents. PGV-0 and PGV-1, a curcumin analogue showed potency as co-chemotherapeutic agent with doxorubicin. Our previous study of PGV-0 and PGV-1 showed cytotoxic activity in T47D cells. Therefore, the aim of this research is to examine the synergistic effect of PGV-0, PGV-1 on the cytotoxic activity of doxorubicin through cell cycle modulation and apoptotic induction on MCF-7 breast cancer cell lines. The cytotoxic assay of PGV-0, PGV-1, doxorubicin, and their combination were carried out by using MTT assay. Cell cycle distribution and apoptosis were determined by flowcytometer FACS-Calibur and the flowcytometry data was analyzed using Cell Quest program. Single treatment of PGV-0, PGV-1 and doxorubicin showed cytotoxic effect on MCF-7 with cell viability IC50 value 50 µM, 6 µM and 350 nM respectively. Single treatment of Doxorubicin 175 nM induced G2/M arrest. Single treatment of PGV-0 5 µM induced G2/M arrest while in higher dose 12.5  µM, PGV-0 induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 5 µM induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 12.5 µM also increased apoptosis induction. Single treatment of PGV-1 0.6 µM induced G1 arrest while in higher dose 1.5  µM, PGV-1 induced apoptosis. Combination of doxorubicin 175 nM and PGV-1 0.6 µM induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 1.5 µM also increased apoptosis induction. PGV-0 and PGV-1 are potential to be delevoped as co-chemotherapeutic agent for breast cancer by inducing apoptosis and cell cycle modulation, but the molecular mechanism need to be explored detail.  Key words: PGV-0, PGV-1, doxorubicin, co-chemotherapy, breast cancer, cell cycle arrest, apoptosis

Abstract 28: Increased Expression Of Mitochondrial Inducible Nitric Oxide Synthase By Heat Shock Protein Hsp22/h11 Kinase Promotes Oxidative Phosphorylation In Mammalian Heart

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Hongyu Qiu ◽  
Eman Rashed ◽  
Christophe Depre
Keyword(s):  
Nitric Oxide ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Inos Expression ◽  
Mitochondrial Localization ◽  
Over Expression ◽  
Mitochondrial Translocation ◽  
Oxide Synthase ◽  
Stimulation Of

Aims: Stress-inducible heat shock protein 22 (Hsp22) confers protection against ischemia through induction of the inducible isoform of nitric oxide synthase (iNOS). Hsp22 over-expression in vivo significantly stimulates cardiac mitochondrial respiration, whereas Hsp22 deletion in vivo shows a reciprocal effect. It has also been shown in Drosophila that Hsp22 is expressed in the mitochondria that depends on its N-terminal domain. We hypothesized that Hsp22-mediated regulation of mitochondrial function is dependent upon its mitochondrial translocation together with iNOS. Methods and Results: Adenoviruses harboring either the full coding sequence of Hsp22 (Ad-WT-Hsp22) or a mutant lacking a 20 amino acid putative N-terminal mitochondrial localization sequence (Ad-N20-Hsp22) were generated, and infected in rat neonatal cardiomyocytes. Compared to β-Gal control, Ad-WT-Hsp22 accumulated in mitochondria by 2.5 fold (P<0.05), reduced chelerythrine-induced apoptosis by 60% (P<0.01), and increased oxygen consumption rate by 2-fold (P<0.01). This latter effect was abolished upon addition of the specific iNOS inhibitor, 1400W. Ad-WT-Hsp22 significantly increased global iNOS expression by about 2-fold (P<0.01), and also increased its mitochondrial localization by 2.5 fold vs β-gal (P<0.05). Upon comparable over-expression, the Ad-N20-Hsp22 mutant did not show significant mitochondrial translocation, protection against apoptosis or stimulation of mitochondrial respiration. Although Ad-N20-Hsp22 did increase global iNOS expression by 6-fold it did not significantly promote iNOS mitochondrial translocation. Conclusion: Translocation of both Hsp22 and iNOS to the mitochondria is necessary for the stimulation of oxidative metabolism and protection against apoptosis.

Synthesis and anticancer activity of some pyrido[2,3-d]pyrimidine derivatives as apoptosis inducers and cyclin-dependent kinase inhibitors

2019 ◽  
Vol 11 (18) ◽  
pp. 2395-2414 ◽  
Author(s):  
Safinaz E-S Abbas ◽  
Riham F George ◽  
Eman M Samir ◽  
Mostafa MA Aref ◽  
Hatem A Abdel-Aziz
Keyword(s):  
Cell Cycle ◽  
Anticancer Agents ◽  
Kinase Inhibitors ◽  
Cytotoxic Agents ◽  
Cyclin Dependent Kinase ◽  
Apoptosis Induction ◽  
Pyrimidine Derivatives ◽  
Induced Apoptosis ◽  
Emergence Of Resistance ◽  
Mcf 7

Aim: Due to emergence of resistance to available anticancer agents, there is a need to search for new cytotoxic agents. Methods: Pyrido[2,3- d]pyrimidines (4–6) and their tricyclic derivatives (7–13) were prepared and screened for their cytotoxicity against breast MCF-7, prostate PC-3 and lung A-549 cancer cell lines as well as normal fibroblasts WI-38. Results: The most active compounds were 6b, 6e and 8d compared with doxorubicin. Moreover, compounds 6b and 8d induced apoptosis in PC-3 and MCF-7, respectively via activation of CASP3 (in PC-3 only), Bax, p53 and down regulation of Bcl2 in addition to CDK4/6 inhibition. Conclusion: Pyrido[2,3- d]pyrimidine represents an important core for discovery of new potent cytotoxic agents acting on the cell cycle via apoptosis induction through either intrinsic or extrinsic pathways.

scholarly journals Stretching magnitude–dependent inactivation of AKT by ROS led to enhanced p53 mitochondrial translocation and myoblast apoptosis

2019 ◽  
Vol 30 (10) ◽  
pp. 1182-1197 ◽  
Author(s):  
Jing Song ◽  
Yaqi Wang ◽  
Xiao Yuan ◽  
Qiuxia Ji ◽  
Cunhui Fan ◽  
...  
Keyword(s):  
P53 Protein ◽  
Akt Pathway ◽  
Ros Generation ◽  
C2c12 Myoblast ◽  
Wild Type ◽  
Nuclear Targeting ◽  
Mitochondrial Translocation ◽  
Dependent Inactivation ◽  
Mitochondrial Trafficking ◽  
Induced Apoptosis

Previously, we had shown that high magnitude stretch (HMS), rather than low magnitude stretch (LMS), induced significant apoptosis of skeletal muscle C2C12 myoblasts. However, the molecular mechanism remains obscure. In this study, we found that p53 protein accumulated in the nucleus of LMS-loaded cells, whereas it translocated into mitochondria of HMS-loaded cells. Knocking down endogenous p53 by shRNA abrogated HMS-induced apoptosis. Furthermore, we demonstrated that overaccumulation of reactive oxygen species (ROS) during HMS-inactivated AKT that was activated in LMS-treated cells, which accounted for the distinct p53 subcellular localizations under HMS and LMS. Blocking ROS generation by N-acetylcysteine (NAC) or overexpressing constitutively active AKT vector (CA-AKT) inhibited HMS-incurred p53 mitochondrial translocation and promoted its nuclear targeting. Moreover, both NAC and CA-AKT significantly attenuated HMS-induced C2C12 apoptosis. Finally, we found that Ser389 phosphorylation of p53 was a downstream event of ROS-inactivated AKT pathway, which was critical to p53 mitochondrial trafficking during HMS stimuli. Transfecting p53-shRNA C2C12s with the mutant p53 (S389A) that was unable to target p53 to mitochondria underwent significantly lower apoptosis than transfection with wild-type p53. Altogether, our study uncovered that mitochondrial localization of p53, resulting from p53 Ser389 phosphorylation through ROS-inactivated AKT pathway, prompted C2C12 myoblast apoptosis during HMS stimulation.

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