scholarly journals Targeting Oxidative Phosphorylation-Proteasome Activity in Extracellular Detached Cells Promotes Anoikis and Inhibits Metastasis

Life ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Funmilayo O. Adeshakin ◽  
Adeleye O. Adeshakin ◽  
Zhao Liu ◽  
Jian Cheng ◽  
Pengchao Zhang ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Tumor Cells ◽  
Proteasome Inhibitors ◽  
Protein Accumulation ◽  
Misfolded Protein ◽  
Anoikis Resistance ◽  
Atp Production ◽  
Metastatic Cells ◽  
Melanoma Model ◽  
Enhanced Expression

Metastasis arises owing to tumor cells’ capacity to evade pro-apoptotic signals. Anoikis—the apoptosis of detached cells (from the extracellular matrix (ECM)) is often circumvented by metastatic cells as a result of biochemical and molecular transformations. These facilitate cells’ ability to survive, invade and reattach to secondary sites. Here, we identified deregulated glucose metabolism, oxidative phosphorylation, and proteasome in anchorage-independent cells compared to adherent cells. Metformin an anti-diabetic drug that reduces blood glucose (also known to inhibit mitochondrial Complex I), and proteasome inhibitors were employed to target these changes. Metformin or proteasome inhibitors alone increased misfolded protein accumulation, sensitized tumor cells to anoikis, and impaired pulmonary metastasis in the B16F10 melanoma model. Mechanistically, metformin reduced cellular ATP production, activated AMPK to foster pro-apoptotic unfolded protein response (UPR) through enhanced expression of CHOP in ECM detached cells. Furthermore, AMPK inhibition reduced misfolded protein accumulation, thus highlight relevance of AMPK activation in facilitating metformin-induced stress and UPR cell death. Our findings provide insights into the molecular biology of anoikis resistance and identified metformin and proteasome inhibitors as potential therapeutic options for tumor metastasis.

Antitumor Activity and Underlying Mechanism of Phomoxanthone B in MCF7 Cells

2020 ◽  
Vol 20 ◽  
Author(s):  
Chuan Chen ◽  
Ziyue Zhao ◽  
Qian Dong ◽  
XueHui Gao ◽  
Huibin Xu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Antitumor Activity ◽  
Oxidative Phosphorylation ◽  
Tumor Cells ◽  
Transcriptome Analysis ◽  
Mcf7 Cells ◽  
Er Positive ◽  
Induced Apoptosis ◽  
Positive Breast Cancer

Background:: Xanthones are a class of heterocyclic natural products, which are promising sources of anticancer leads. Phomoxanthone B（PXB）and Phomoxanthone A（PXA）are xanthone dimers. PXA is well studied as an anti-cancer agent, but PXB is not. In our study, PXB was isolated from the endophytic fungus Phomopsis sp. By254. Objective:: The purpose of this study was to identify the underlying anti-tumor mechanisms of PXB in breast cancer MCF7 cell line. Methods:: Apoptosis, cell cycle, proliferation, invasion and migration assays were used to assess the antitumor activity of PXB. RNA sequencing was used to analyze the effect of PXB treatment on gene expression in MCF7 cells. Results:: PXB showed cytotoxicity toward a variety of tumor cells, especially MCF7 cells. PXB inhibited the migration and invasion, arrested cell cycle at G2/M phase and induced apoptosis associated with caspase-3 activation in MCF7 cells. The detailed transcriptome analysis revealed that PXB affected several pathways related to tumorigenesis, metabolisms-, and oxidative phosphorylation in MCF7 cells. KEGG transcriptome analysis revealed that PXB upregulated pro-survival signal pathways such as MAPK, PI3K-AKT and STAT3 pathways. We found that PXB also significantly upregulated the expression of IL24, DDIT3 and XAF1, which may contribute to PXB-induced apoptosis. We further found that PXB may downregulate oxidative phosphorylation by decreasing the expression of electron transport chain genes, especially MT-ND1, which is a potential unfavorable prognostic marker for ER-positive breast cancer. Conclusion:: PXB exerts strong cytotoxicity against human tumor cells and has a potential for ER-positive breast cancer treatment.

scholarly journals Epilepsy in Mitochondrial Diseases—Current State of Knowledge on Aetiology and Treatment

Children ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 532
Author(s):  
Dorota Wesół-Kucharska ◽  
Dariusz Rokicki ◽  
Aleksandra Jezela-Stanek
Keyword(s):  
Oxidative Phosphorylation ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Disease ◽  
Clinical Picture ◽  
Poor Prognosis ◽  
Treatment Options ◽  
Mitochondrial Diseases ◽  
Energy Deficit ◽  
Atp Production ◽  
Current State

Mitochondrial diseases are a heterogeneous group of diseases resulting from energy deficit and reduced adenosine triphosphate (ATP) production due to impaired oxidative phosphorylation. The manifestation of mitochondrial disease is usually multi-organ. Epilepsy is one of the most common manifestations of diseases resulting from mitochondrial dysfunction, especially in children. The onset of epilepsy is associated with poor prognosis, while its treatment is very challenging, which further adversely affects the course of these disorders. Fortunately, our knowledge of mitochondrial diseases is still growing, which gives hope for patients to improve their condition in the future. The paper presents the pathophysiology, clinical picture and treatment options for epilepsy in patients with mitochondrial disease.

scholarly journals Role and Modulation of NK Cells in Multiple Myeloma

Hemato ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 167-181
Author(s):  
Marie Thérèse Rubio ◽  
Adèle Dhuyser ◽  
Stéphanie Nguyen
Keyword(s):  
Multiple Myeloma ◽  
Monoclonal Antibodies ◽  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Killer Cell ◽  
Proteasome Inhibitors ◽  
Disease Evolution ◽  
Cell Functions

Myeloma tumor cells are particularly dependent on their microenvironment and sensitive to cellular antitumor immune response, including natural killer (NK) cells. These later are essential innate lymphocytes implicated in the control of viral infections and cancers. Their cytotoxic activity is regulated by a balance between activating and inhibitory signals resulting from the complex interaction of surface receptors and their respective ligands. Myeloma disease evolution is associated with a progressive alteration of NK cell number, phenotype and cytotoxic functions. We review here the different therapeutic approaches that could restore or enhance NK cell functions in multiple myeloma. First, conventional treatments (immunomodulatory drugs-IMids and proteasome inhibitors) can enhance NK killing of tumor cells by modulating the expression of NK receptors and their corresponding ligands on NK and myeloma cells, respectively. Because of their ability to kill by antibody-dependent cell cytotoxicity, NK cells are important effectors involved in the efficacy of anti-myeloma monoclonal antibodies targeting the tumor antigens CD38, CS1 or BCMA. These complementary mechanisms support the more recent therapeutic combination of IMids or proteasome inhibitors to monoclonal antibodies. We finally discuss the ongoing development of new NK cell-based immunotherapies, such as ex vivo expanded killer cell immunoglobulin-like receptors (KIR)-mismatched NK cells, chimeric antigen receptors (CAR)-NK cells, check point and KIR inhibitors.

scholarly journals Inhibition of retrograde transport modulates misfolded protein accumulation and clearance in motoneuron diseases

Autophagy ◽  
2017 ◽  
Vol 13 (8) ◽  
pp. 1280-1303 ◽  
Author(s):  
Riccardo Cristofani ◽  
Valeria Crippa ◽  
Paola Rusmini ◽  
Maria Elena Cicardi ◽  
Marco Meroni ◽  
...  
Keyword(s):  
Retrograde Transport ◽  
Protein Accumulation ◽  
Misfolded Protein ◽  
Motoneuron Diseases

Carfilzomib can induce tumor cell death through selective inhibition of the chymotrypsin-like activity of the proteasome

Blood ◽  
2009 ◽  
Vol 114 (16) ◽  
pp. 3439-3447 ◽  
Author(s):  
Francesco Parlati ◽  
Susan J. Lee ◽  
Monette Aujay ◽  
Erika Suzuki ◽  
Konstantin Levitsky ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Mononuclear Cells ◽  
Proteasome Inhibitors ◽  
Selective Inhibition ◽  
Tumor Cell Death ◽  
Clinical Safety ◽  
Peripheral Blood Mononuclear ◽  
Non Hodgkin Lymphoma ◽  
Proteasome Subunits ◽  
The Impact

Abstract Carfilzomib is a proteasome inhibitor in clinical development that primarily targets the chymotrypsin-like (CT-L) subunits in both the constitutive proteasome (c20S) and the immunoproteasome (i20S). To investigate the impact of inhibiting the CT-L activity with carfilzomib, we set out to quantitate the levels of CT-L subunits β5 from the c20S and LMP7 from the i20S in normal and malignant hematopoietic cells. We found that the i20S is a major form of the proteasome expressed in cells of hematopoietic origin, including multiple myeloma (MM) CD138+ tumor cells. Although specific inhibition of either LMP7 or β5 alone was insufficient to produce an antitumor response, inhibition of all proteasome subunits was cytotoxic to both hematologic tumor cells and peripheral blood mononuclear cells. However, selective inhibition of both β5 and LMP7 was sufficient to induce an antitumor effect in MM, non-Hodgkin lymphoma, and leukemia cells while minimizing the toxicity toward nontransformed cells. In MM tumor cells, CT-L inhibition alone was sufficient to induce proapoptotic sequelae, including proteasome substrate accumulation, Noxa and caspase 3/7 induction, and phospho-eIF2α suppression. These data support a hypothesis that hematologic tumor cells are uniquely sensitive to CT-L inhibition and provide a mechanistic understanding of the clinical safety profile and antitumor activity of proteasome inhibitors.

Dual Mutations Reveal Interactions Between Components of Oxidative Phosphorylation in Kluyveromyces lactis

Genetics ◽  
2001 ◽  
Vol 159 (3) ◽  
pp. 929-938
Author(s):  
G D Clark-Walker ◽  
X J Chen
Keyword(s):  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Kluyveromyces Lactis ◽  
Mitochondrial Protein ◽  
Proton Pumping ◽  
Nuclear Genes ◽  
Suppressor Activity ◽  
Inner Membrane ◽  
Atp Production

Abstract Loss of mtDNA or mitochondrial protein synthesis cannot be tolerated by wild-type Kluyveromyces lactis. The mitochondrial function responsible for ρ0-lethality has been identified by disruption of nuclear genes encoding electron transport and F0-ATP synthase components of oxidative phosphorylation. Sporulation of diploid strains heterozygous for disruptions in genes for the two components of oxidative phosphorylation results in the formation of nonviable spores inferred to contain both disruptions. Lethality of spores is thought to result from absence of a transmembrane potential, ΔΨ, across the mitochondrial inner membrane due to lack of proton pumping by the electron transport chain or reversal of F1F0-ATP synthase. Synergistic lethality, caused by disruption of nuclear genes, or ρ0-lethality can be suppressed by the atp2.1 mutation in the β-subunit of F1-ATPase. Suppression is viewed as occurring by an increased hydrolysis of ATP by mutant F1, allowing sufficient electrogenic exchange by the translocase of ADP in the matrix for ATP in the cytosol to maintain ΔΨ. In addition, lethality of haploid strains with a disruption of AAC encoding the ADP/ATP translocase can be suppressed by atp2.1. In this case suppression is considered to occur by mutant F1 acting in the forward direction to partially uncouple ATP production, thereby stimulating respiration and relieving detrimental hyperpolarization of the inner membrane. Participation of the ADP/ATP translocase in suppression of ρ0-lethality is supported by the observation that disruption of AAC abolishes suppressor activity of atp2.1.

scholarly journals Gene by environmental interactions affecting oxidative phosphorylation and thermal sensitivity

2016 ◽  
Vol 311 (1) ◽  
pp. R157-R165 ◽  
Author(s):  
Tara Z. Baris ◽  
Pierre U. Blier ◽  
Nicolas Pichaud ◽  
Douglas L. Crawford ◽  
Marjorie F. Oleksiak
Keyword(s):  
Oxidative Phosphorylation ◽  
Complex I ◽  
Thermal Sensitivity ◽  
Single Species ◽  
Mitochondrial Haplotype ◽  
Acclimation Temperature ◽  
Atp Production ◽  
Acute Response ◽  
Relative Contribution ◽  
Mitochondrial Genotype

The oxidative phosphorylation (OxPhos) pathway is responsible for most aerobic ATP production and is the only metabolic pathway with proteins encoded by both nuclear and mitochondrial genomes. In studies examining mitonuclear interactions among distant populations within a species or across species, the interactions between these two genomes can affect metabolism, growth, and fitness, depending on the environment. However, there is little data on whether these interactions impact natural populations within a single species. In an admixed Fundulus heteroclitus population with northern and southern mitochondrial haplotypes, there are significant differences in allele frequencies associated with mitochondrial haplotype. In this study, we investigate how mitochondrial haplotype and any associated nuclear differences affect six OxPhos parameters within a population. The data demonstrate significant OxPhos functional differences between the two mitochondrial genotypes. These differences are most apparent when individuals are acclimated to high temperatures with the southern mitochondrial genotype having a large acute response and the northern mitochondrial genotype having little, if any acute response. Furthermore, acute temperature effects and the relative contribution of Complex I and II depend on acclimation temperature: when individuals are acclimated to 12°C, the relative contribution of Complex I increases with higher acute temperatures, whereas at 28°C acclimation, the relative contribution of Complex I is unaffected by acute temperature change. These data demonstrate a complex gene by environmental interaction affecting the OxPhos pathway.

scholarly journals Senescence-associated changes in respiration and oxidative phosphorylation in primary human fibroblasts

2004 ◽  
Vol 380 (3) ◽  
pp. 919-928 ◽  
Author(s):  
Eveline HUTTER ◽  
Kathrin RENNER ◽  
Gerald PFISTER ◽  
Petra STÖCKL ◽  
Pidder JANSEN-DÜRR ◽  
...  
Keyword(s):  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Replicative Senescence ◽  
Citrate Synthase ◽  
Human Fibroblasts ◽  
Respiratory Control ◽  
Compensatory Mechanisms ◽  
Intact Cells ◽  
Atp Production ◽  
Human Diploid Fibroblasts

Limitation of lifespan in replicative senescence is related to oxidative stress, which is probably both the cause and consequence of impaired mitochondrial respiratory function. The respiration of senescent human diploid fibroblasts was analysed by highresolution respirometry. To rule out cell-cycle effects, proliferating and growth-arrested young fibroblasts were used as controls. Uncoupled respiration, as normalized to citrate synthase activity, remained unchanged, reflecting a constant capacity of the respiratory chain. Oligomycin-inhibited respiration, however, was significantly increased in mitochondria of senescent cells, indicating a lower coupling of electron transport with phosphorylation. In contrast, growth-arrested young fibroblasts exhibited a higher coupling state compared with proliferating controls. In intact cells, partial uncoupling may lead to either decreased oxidative ATP production or a compensatory increase in routine respiration. To distinguish between these alternatives, we subtracted oligomycin-inhibited respiration from routine respiration, which allowed us to determine the part of respiratory activity coupled with ATP production. Despite substantial differences in the respiratory control ratio, ranging from 4 to 11 in the different experimental groups, a fixed proportion of respiratory capacity was maintained for coupled oxidative phosphorylation in all the experimental groups. This finding indicates that the senescent cells fully compensate for increased proton leakage by enhanced electron-transport activity in the routine state. These results provide a new insight into age-associated defects in mitochondrial function and compensatory mechanisms in intact cells.

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