scholarly journals iPLA2β-mediated lipid detoxification controls p53-driven ferroptosis independent of GPX4

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Delin Chen ◽  
Bo Chu ◽  
Xin Yang ◽  
Zhaoqi Liu ◽  
Ying Jin ◽  
...  
Keyword(s):  
Tumor Suppression ◽  
Normal Development ◽  
Oxygen Species ◽  
Glycerol Backbone ◽  
Independent Manner ◽  
Obvious Effect ◽  
Normal Tissues ◽  
Induced Stress ◽  
Promising Therapeutic Target ◽  
Oxidized Fatty Acids

AbstractHere, we identify iPLA2β as a critical regulator for p53-driven ferroptosis upon reactive oxygen species (ROS)-induced stress. The calcium-independent phospholipase iPLA2β is known to cleave acyl tails from the glycerol backbone of lipids and release oxidized fatty acids from phospholipids. We found that iPLA2β-mediated detoxification of peroxidized lipids is sufficient to suppress p53-driven ferroptosis upon ROS-induced stress, even in GPX4-null cells. Moreover, iPLA2β is overexpressed in human cancers; inhibition of endogenous iPLA2β sensitizes tumor cells to p53-driven ferroptosis and promotes p53-dependent tumor suppression in xenograft mouse models. These results demonstrate that iPLA2β acts as a major ferroptosis repressor in a GPX4-independent manner. Notably, unlike GPX4, loss of iPLA2β has no obvious effect on normal development or cell viability in normal tissues but iPLA2β plays an essential role in regulating ferroptosis upon ROS-induced stress. Thus, our study suggests that iPLA2β is a promising therapeutic target for activating ferroptosis-mediated tumor suppression without serious toxicity concerns.

Targeting Nodal and Cripto-1: Perspectives Inside Dual Potential Theranostic Cancer Biomarkers

2019 ◽  
Vol 26 (11) ◽  
pp. 1994-2050 ◽  
Author(s):  
Annamaria Sandomenico ◽  
Menotti Ruvo
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Normal Development ◽  
Cancer Biomarkers ◽  
Normal Tissues ◽  
Tumor Relapse ◽  
Developmental Factors ◽  
Theranostic Agents ◽  
Tumor Types ◽  
Embryonic Signaling

Background:Elucidating the mechanisms of recurrence of embryonic signaling pathways in tumorigenesis has led to the discovery of onco-fetal players which have physiological roles during normal development but result aberrantly re-activated in tumors. In this context, Nodal and Cripto-1 are recognized as onco-developmental factors, which are absent in normal tissues but are overexpressed in several solid tumors where they can serve as theranostic agents.Objective:To collect, review and discuss the most relevant papers related to the involvement of Nodal and Cripto-1 in the development, progression, recurrence and metastasis of several tumors where they are over-expressed, with a particular attention to their occurrence on the surface of the corresponding sub-populations of cancer stem cells (CSC).Results:We have gathered, rationalized and discussed the most interesting findings extracted from some 370 papers related to the involvement of Cripto-1 and Nodal in all tumor types where they have been detected. Data demonstrate the clear connection between Nodal and Cripto-1 presence and their multiple oncogenic activities across different tumors. We have also reviewed and highlighted the potential of targeting Nodal, Cripto-1 and the complexes that they form on the surface of tumor cells, especially of CSC, as an innovative approach to detect and suppress tumors with molecules that block one or more mechanisms that they regulate.Conclusion:Overall, Nodal and Cripto-1 represent two innovative and effective biomarkers for developing potential theranostic anti-tumor agents that target normal as well as CSC subpopulations and overcome both pharmacological resistance and tumor relapse.

scholarly journals MACC1 Contributes to the Development of Osteosarcoma Through Regulation of the HGF/c-Met Pathway and Microtubule Stability

2020 ◽  
Vol 8 ◽  
Author(s):  
Jia Wen ◽  
Yi Xie ◽  
Yingqiang Zhang ◽  
Jiazhen Li ◽  
Jiaping Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tumor Growth ◽  
Signaling Pathway ◽  
Normal Tissues ◽  
Microtubule Stability ◽  
Promising Therapeutic Target ◽  
Tumor Growth And Metastasis ◽  
Hepatocyte Growth ◽  
Proliferative Ability

Osteosarcoma (OS) is the most prevalent human bone malignancy, and presents a global annual morbidity of approximately five cases per million. Notably, precise and efficient targeted therapy has become the most promising strategy for the treatment of OS; however, there is still an urgent need for the identification of suitable therapeutic targets. Metastasis-associated in colon cancer 1 (MACC1) was first identified in colon tumors by differential display RT-PCR, and was shown to be involved in the regulation of colon tumor growth and metastasis through the hepatocyte growth factor (HGF)/c-Met signaling pathway. Additionally, MACC1 overexpression has been reported to induce the growth of several types of cancers, including glioblastoma multiforme and gastric cancer. However, whether MACC1 also plays a role in the progression of OS remains unclear. In this study, we found that MACC1 was highly expressed in human OS tissues, as well as in U-2OS and MG-63 cells, when compared with normal tissues and osteoblasts, respectively. Our data further indicated that MACC1 expression was correlated with several clinicopathological features of OS. Through in vitro assays, we found that MACC1 depletion markedly suppressed the proliferative ability of both OS cells and endothelial cells, and inhibited the angiogenic capacity of endothelial cells. Similarly, MACC1 depletion inhibited tumor growth, metastasis, and angiogenesis in mice. Mechanistically, we found that MACC1 could bind to the MET promoter, and enhanced the proliferation of both OS cells and endothelial cells through the HGF/c-Met signaling pathway. Furthermore, we show that MACC1 also promoted angiogenesis by regulating microtubule dynamics, thereby promoting the progression of OS. Our results indicate that MACC1 may be a new and promising therapeutic target for the treatment of OS.

scholarly journals CCT3 acts upstream of YAP and TFCP2 as a potential target and tumour biomarker in liver cancer

2019 ◽  
Vol 10 (9) ◽  
Author(s):  
Ya Liu ◽  
Xiao Zhang ◽  
Jiafei Lin ◽  
Yuxin Chen ◽  
Yongxia Qiao ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Therapeutic Target ◽  
Potential Therapeutic Target ◽  
Liver Malignancy ◽  
Independent Manner ◽  
Diagnostic Biomarkers ◽  
Ubiquitin Protein Ligase ◽  
Promising Therapeutic Target ◽  
Potential Biomarker ◽  
Diagnostic Capacity

Abstract Although Yes-associated protein (YAP) is very important to liver cancer, its nuclear localisation prevents consideration as a promising therapeutic target and a diagnostic biomarker. Recently, we reported that the protumourigenic roles of YAP in liver cancer are indispensable for transcription factor CP2 (TFCP2) in a Hippo-independent manner; however, proteins that act upstream to simultaneously control YAP and TFCP2 remain unclear. The aim of this study was to uncover such proteins and evaluate whether they are potential YAP-associated therapeutic targets and diagnostic biomarkers. Mass spectrometry revealed that chaperonin containing TCP1 subunit 3 (CCT3) co-interact with YAP and TFCP2, and notably, CCT3 is a non-nuclear protein. CCT3 was elevated in liver cancer, and its higher expression was associated with poorer overall survival. Inhibiting CCT3 resulted in a suppressed transformative phenotype in liver cancer cells, suggesting that CCT3 might be a potential therapeutic target. CCT3 prolonged half-life of YAP and TFCP2 by blocking their ubiquitination caused by poly(rC) binding protein 2 (PCBP2) in a beta-transducin repeat containing E3 ubiquitin protein ligase (βTrCP)-independent manner. Interestingly, PCBP2 directly interacted with YAP via a WB motif-WW domain interaction, whereas indirectly interacted with TFCP2 via the aid of YAP. Furthermore, CCT3 was capable of separating PCBP2-YAP interactions, thereby preventing YAP and TFCP2 from PCBP2-induced ubiquitination. Moreover, YAP and TFCP2 were downstream of CCT3 to positively control tumourigenesis, yet such effects were inhibited by PCBP2. Clinically, CCT3 was positively correlated with YAP and TFCP2, and elevated levels of the CCT3-YAP-TFCP2 axis might be critical for liver malignancy. In addition, seral-CCT3 was proven to be a potential biomarker, and its diagnostic capacity was better than that of alpha fetoprotein (AFP) to a certain extent. Together, CCT3 acts as a trigger of YAP and TFCP2 to affect tumourigenesis and serves as a potential therapeutic target and biomarker in liver cancer.

scholarly journals Mitochondrial Roles and Cytoprotection in Chronic Liver Injury

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Davide Degli Esposti ◽  
Jocelyne Hamelin ◽  
Nelly Bosselut ◽  
Raphaël Saffroy ◽  
Mylène Sebagh ◽  
...  
Keyword(s):  
Liver Diseases ◽  
Hepatic Metabolism ◽  
Chronic Liver ◽  
Oxygen Species ◽  
Organelle Biogenesis ◽  
Chronic Liver Diseases ◽  
Chronic Liver Injury ◽  
Promising Therapeutic Target ◽  
Apoptosis And Necrosis

The liver is one of the richest organs in terms of number and density of mitochondria. Most chronic liver diseases are associated with the accumulation of damaged mitochondria. Hepatic mitochondria have unique features compared to other organs' mitochondria, since they are the hub that integrates hepatic metabolism of carbohydrates, lipids and proteins. Mitochondria are also essential in hepatocyte survival as mediator of apoptosis and necrosis. Hepatocytes have developed different mechanisms to keep mitochondrial integrity or to prevent the effects of mitochondrial lesions, in particular regulating organelle biogenesis and degradation. In this paper, we will focus on the role of mitochondria in liver physiology, such as hepatic metabolism, reactive oxygen species homeostasis and cell survival. We will also focus on chronic liver pathologies, especially those linked to alcohol, virus, drugs or metabolic syndrome and we will discuss how mitochondria could provide a promising therapeutic target in these contexts.

scholarly journals BRG1 Is Required for Formation of Senescence-Associated Heterochromatin Foci Induced by Oncogenic RAS or BRCA1 Loss

2013 ◽  
Vol 33 (9) ◽  
pp. 1819-1829 ◽  
Author(s):  
Zhigang Tu ◽  
Xinying Zhuang ◽  
Yong-Gang Yao ◽  
Rugang Zhang
Keyword(s):  
Dna Damage ◽  
Molecular Mechanism ◽  
Chromatin Remodeling ◽  
Cellular Senescence ◽  
Chromatin Immunoprecipitation ◽  
Tumor Suppression ◽  
Gene Promoters ◽  
Independent Manner ◽  
Oncogenic Ras ◽  
Suppression Mechanism

Cellular senescence is an important tumor suppression mechanism. We have previously reported that both oncogene-induced dissociation of BRCA1 from chromatin and BRCA1 knockdown itself drive senescence by promoting formation of s enescence- a ssociated h eterochromatin f oci (SAHF). However, the molecular mechanism by which BRCA1 regulates SAHF formation and senescence is unclear. BRG1 is a chromatin-remodeling factor that interacts with BRCA1 and pRB. Here we show that BRG1 is required for SAHF formation and senescence induced by oncogenic RAS or BRCA1 loss. The interaction between BRG1 and BRCA1 is disrupted during senescence. This correlates with an increased level of chromatin-associated BRG1 in senescent cells. BRG1 knockdown suppresses the formation of SAHF and senescence, while it has no effect on BRCA1 chromatin dissociation induced by oncogenic RAS, indicating that BRG1 functions downstream of BRCA1 chromatin dissociation. Furthermore, BRG1 knockdown inhibits SAHF formation and senescence induced by BRCA1 knockdown. Conversely, BRG1 overexpression drives SAHF formation and senescence in a DNA damage-independent manner. This effect depends upon BRG1's chromatin-remodeling activity as well as the interaction between BRG1 and pRB. Indeed, the interaction between BRG1 and pRB is enhanced during senescence. Chromatin immunoprecipitation analysis revealed that BRG1's association with the human CDKN2A and CDKN1A gene promoters was enhanced during senescence induced by oncogenic RAS or BRCA1 knockdown. Consistently, knockdown of pRB, p21 CIP1 , and p16 INK4a , but not p53, suppressed SAHF formation induced by BRG1. Together, these studies reveal the molecular underpinning by which BRG1 acts downstream of BRCA1 to promote SAHF formation and senescence.

Induction of Noxa Via Generation of Reactive Oxygen Species Plays a Key Role in Induction of CLL Cell Apoptosis by Two Novel p53-Independent Cytotoxic Agents.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2752-2752
Author(s):  
Andrew Steele ◽  
Archibald G Prentice ◽  
Anastasios Chanalaris ◽  
A. Victor Hoffbrand ◽  
Kate Cwynarski ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Apoptosis ◽  
Conflicts Of Interest ◽  
Reactive Oxygen ◽  
Cytotoxic Agents ◽  
Ros Generation ◽  
Radical Scavenger ◽  
Oxygen Species ◽  
Independent Manner ◽  
Factor C

Abstract Abstract 2752 Poster Board II-728 Approximately 15% of CLL patients present with a deletion of chromosome 17p, resulting in the loss of the p53 gene. The percentage of 17p-deleted patients can increase to between 30–50% following treatment with cytotoxic agents which induce CLL apoptosis via upregulation of p53. Therefore, identification of novel agents which kill CLL cells independently of p53 is of crucial importance. We have recently shown that two chemically unrelated agents, 2-phenylacetylenesulfonamide (PAS) and the sesquiterpene lactone LC1 kill CLL cells regardless of the functional status of p53. Furthermore, in contrast to the conventional drugs chlorambucil and fludarabine, PAS and LC1 induce apoptosis in the absence of p53 elevation. However, the mechanisms of action by which these agents induce p53-independent apoptosis are unclear. We have previously shown that both PAS and LC1 initiated CLL cell apoptosis within 6-10h with, maximal killing by 48h. Here we show that treatment of CLL cells with either agent results in the generation of reactive oxygen species (ROS), the activating phosphorylation of the pro-apoptotic MAP kinase family member JNK (Fig 1), resulting in turn in upregulation of its downstream target, the transcription factor c-JUN (Fig 2). The BH3-only pro-apoptotic protein Noxa was originally described as a pro-apoptotic target for upregulation by p53. However, both PAS (Figs1 and 2) and LC1 upregulated Noxa in a p53-independent manner. Addition of N-acetylcysteine (NAC), a free radical scavenger, decreased ROS generation by PAS or LC1 and also prevented phosphorylation of JNK and Noxa upregulation (Fig 1) and also the upregulation of c-JUN. NAC also strikingly abrogated apoptosis induction by either agent, as shown by quantitation of cleavage of the caspase 3 substrate poly (ADP ribose) polymerase (PARP; Fig 1). Taken together, the data suggest both PAS and LC1 induce p53-independent apoptosis via upregulation of ROS and the subsequent induction of Noxa. The data are also compatible with a role for JNK and c-JUN in the events leading to Noxa upregulation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals CatB is Critical for Total Catalase Activity and Reduces Bactericidal Effects of Phenazine-1-Carboxylic Acid on Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola

2017 ◽  
Vol 107 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Xiayan Pan ◽  
Jian Wu ◽  
Shu Xu ◽  
Yabing Duan ◽  
Mingguo Zhou
Keyword(s):  
Carboxylic Acid ◽  
Catalase Activity ◽  
Redox Balance ◽  
Xanthomonas Oryzae ◽  
Deletion Mutants ◽  
Oxygen Species ◽  
Bacterial Leaf Streak ◽  
Induced Stress ◽  
Bactericidal Effects ◽  
Increased Sensitivity

Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, and rice bacterial leaf streak, caused by X. oryzae pv. oryzicola, are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species in X. oryzae pv. oryzae. In this study, we found that PCA significantly upregulated the transcript levels of catB and katE, which encode catalases, and that PCA sensitivity was reduced when X. oryzae pvs. oryzae and oryzicola were cultured with exogenous catalase. Furthermore, catB deletion mutants of X. oryzae pvs. oryzae and oryzicola showed dramatically decreased total catalase activity, increased sensitivity to PCA, and reduced virulence in rice. In contrast, deletion mutants of srpA and katG, which also encode catalases, exhibited little change in PCA sensitivity. The results indicate that catB in both X. oryzae pvs. oryzae and oryzicola encodes a catalase that helps protect the bacteria against PCA-induced stress.

scholarly journals Reactive Oxygen Species Are Involved in Brassinosteroid-Induced Stress Tolerance in Cucumber

2009 ◽  
Vol 150 (2) ◽  
pp. 801-814 ◽  
Author(s):  
Xiao-Jian Xia ◽  
Yan-Jie Wang ◽  
Yan-Hong Zhou ◽  
Yuan Tao ◽  
Wei-Hua Mao ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Stress Tolerance ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Induced Stress

scholarly journals Evolutionary GEM: Evolution of Cytochrome c Oxidase IV Regulation in Mammals

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Joseph Brockman ◽  
Patricia M. Gray
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Hypoxia Inducible Factor ◽  
Aerobic Bacteria ◽  
Oxygen Species ◽  
Independent Manner ◽  
Hypoxia Inducible Factor 1 ◽  
Early Atmosphere ◽  
Responsive Element ◽  
Multicellular Organisms

Aerobic respiration, although metabolically advantageous in O2-rich environments, can be detrimental to the cell when O2 is not fully reduced resulting in cytotoxic reactive oxygen species (ROS) production. Cytochrome c oxidase subunit 4 (COX-4) is primarily responsible for fully reducing O2 during metabolism and exists as COX4-1 and COX4-2 isoforms. The former exists in normoxia, but is replaced by the latter in hypoxia. This change is brought about by two mechanisms, the first involving regulation by hypoxia inducible factor 1 (HIF-1), which directly upregulates COX4-2 and indirectly degrades COX4-1. The second mechanism involves an oxygen responsive element (ORE), which upregulates COX4-2 in a HIF-1 independent manner. The convergence of two unrelated pathways to regulate COX4-1 and COX4-2 would allow cells to optimize their metabolic profile within an environment experiencing varying O2, such as Earth’s early atmosphere in the case of primitive aerobic bacteria or in multicellular organisms where O2 levels vary between tissues such as lung tissue.

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