RelB silencing to reverse tamoxifen resistance by regulating GPx4 and ferroptosis in breast cancer.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e12513-e12513
Author(s):  
Zhi Xu ◽  
Jinhai Tang
Keyword(s):  
Breast Cancer ◽  
Lipid Peroxidation ◽  
Cell Death ◽  
Cell Lines ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Death Process ◽  
Enhancer Element ◽  
High Level

e12513 Background: Tamoxifen(Tam), as an essential therapeutic treatment of estrogen receptor(ER)-positive breast cancer(BCa), has been available for the past three decades. However, the induction of Tam resistance during therapy has indicated a significant challenge with regards to this agent. Tam could increase oxidative stress and induce cell death by regulating reactive oxygen species(ROS). Ferroptosis, a cell death process driven by the accumulation of iron-dependent lipid peroxides, has been induced by inactivation/depletion of glutathione peroxidases(GPxs). Our previous studies found that the expression level of RelB gene, a member of NF-κB family, is negatively correlated with ER targeted by Tam in BCa. Methods: The RelB level of BCa tumor tissues and the corresponding cell lines were examined by immunoblotting and western blot. The effects of Tam on cell viability were determined using colony survival and MTT assay. The ROS and oxygen consumption rates(OCR) were measured using specific ROS detection probes and a Seahorse XF96 Analyzer, respectively. The lipid peroxidation level of cells was analyzed by immunofluorescence assay. The morphological changes of mitochondria were observed by transmission electron microscope. RelB binding to the NF-κB intronic enhancer region of the human GPx4 gene was determined using a ChIP assay. Accordingly, the effect of RelB on BCa Tam resistance was further validated using BCa mice xenograft models. Results: RelB was uniquely expressed at the high level in Tam resistance BCa tissues and cell lines. Down-regulation of RelB based on a CRISPR/Cas9 system remarkably sensitized resistance BCa cells to Tam. Treatment with SN52, a RelB inhibitor, illuminated the role of RelB in Tam-treated BCa cells. The high level of ROS and declination of mitochondrial respiration which induced by Tam were inhibited in resistance cells. Tam enhanced lipid peroxidation with concomitant non-apoptotic cell death, which are negatively regulated by GPx4 activity. In addition to GPx4 knockdown, deferoxamine was able to rescue Tam-induced cell death in BCa cells, verifying that Tam induces cell death partially through ferroptosis. Importantly, RelB upregulates GPx4 expression through binding to an NF-κB enhancer element located at the 5’-flanking region. Consistently, in vivo functional validation confirmed that RelB inhibition not only impairs tumor growth, but also inhibits Tam resistance in nude mice. Conclusions: RelB could inhibit ferroptosis which induced by hydroxyl radicals accumulation through upregulating GPx4 in BCa.

scholarly journals APR-246 induces early cell death by ferroptosis in acute myeloid leukemia.

Haematologica ◽  
2021 ◽  
Author(s):  
Rudy Birsen ◽  
Clement Larrue ◽  
Justine Decroocq ◽  
Natacha Johnson ◽  
Nathan Guiraud ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Lipid Peroxides ◽  
Death Process ◽  
Glutathione Biosynthesis ◽  
Acute Myeloid

APR-246 is a promising new therapeutic agent that targets p53 mutated proteins in myelodysplastic syndromes and in acute myeloid leukemia. APR-246 reactivates the transcriptional activity of p53 mutants by facilitating their binding to DNA target sites. Recent studies in solid cancers have found that APR-246 can also induce p53-independent cell death. In this study, we demonstrate that AML cell death occurring early after APR-246 exposure is suppressed by iron chelators, lipophilic antioxidants and inhibitors of lipid peroxidation, and correlates with the accumulation of markers of lipid peroxidation, thus fulfilling the definition of ferroptosis, a recently described cell death process. The capacity of AML cells to detoxify lipid peroxides by increasing their cystine uptake to maintain major antioxidant molecule glutathione biosynthesis after exposure to APR-246 may be a key determinant of sensitivity to this compound. The association of APR-246 with induction of ferroptosis (either by pharmacological compounds, or genetic inactivation of SLC7A11 or GPX4) had a synergistic effect on the promotion of cell death, both in vivo and ex vivo.

scholarly journals Iron toxicity, lipid peroxidation and ferroptosis after intracerebral haemorrhage

2019 ◽  
Vol 4 (2) ◽  
pp. 93-95 ◽  
Author(s):  
Jieru Wan ◽  
Honglei Ren ◽  
Jian Wang
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Intracerebral Haemorrhage ◽  
Neuronal Death ◽  
Molecular Mechanisms ◽  
Apoptotic Cell ◽  
Iron Toxicity ◽  
Secondary Brain Injury

Intracerebral haemorrhage (ICH) is a devastating type of stroke with high mortality and morbidity. However, we have few options for ICH therapy and limited knowledge about post-ICH neuronal death and related mechanisms. In the aftermath of ICH, iron overload within the perihaematomal region can induce lethal reactive oxygen species (ROS) production and lipid peroxidation, which contribute to secondary brain injury. Indeed, iron chelation therapy has shown efficacy in preclinical ICH studies. Recently, an iron-dependent form of non-apoptotic cell death known as ferroptosis was identified. It is characterised by an accumulation of iron-induced lipid ROS, which leads to intracellular oxidative stress. The ROS cause damage to nucleic acids, proteins and lipid membranes, and eventually cell death. Recently, we and others discovered that ferroptosis does occur after haemorrhagic stroke in vitro and in vivo and contributes to neuronal death. Inhibition of ferroptosis is beneficial in several in vivo and in vitro ICH conditions. This minireview summarises current research on iron toxicity, lipid peroxidation and ferroptosis in the pathomechanisms of ICH, the underlying molecular mechanisms of ferroptosis and the potential for combined therapeutic strategies. Understanding the role of ferroptosis after ICH will provide a vital foundation for cell death-based ICH treatment and prevention.

Autoregulation of MEIS1 through a Distal Enhancer in Acute Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 745-745
Author(s):  
Qianfei Wang ◽  
Jingfang Dong ◽  
Ryan Mattison ◽  
Shyam Prabhakar ◽  
Fabio Eiji Arimura ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Cell Lines ◽  
Reporter Gene ◽  
Genomic Region ◽  
Regulatory Function ◽  
Distal Enhancer ◽  
Enhancer Element ◽  
Two Factors ◽  
High Level

Abstract Aberrant activation of the TALE (three-amino-acid loop extension) homeobox gene MEIS1 is frequently observed in acute leukemia. A high level of Meis1 expression shortens the latency, as well as accelerates the onset and progression of acute myeloid leukemia in mice. Although available data support the notion that MEIS1 is oncogenic by means of overexpression rather than mutation, the molecular mechanism underlying persistent activation of this gene in leukemia remains poorly understood. We have identified a distal enhancer (designated EX) at the MEIS1 locus and found that MEIS1 itself and HOXA9 synergistically activate the regulatory activity of EX through a conserved DNA motif. Using comparative genomics-based strategies, we computationally predicted 14 putative enhancer DNA elements in the 1300 Kb MEIS1 locus. We confirmed that the human sequences of 6 of these 14 elements showed enhancer function as they were able to direct GFP expression in a spatiotemporal manner during embryonic hematopoiesis in an in vivo transgenic zebrafish assay. To explore whether these 6 elements play a role in regulating MEIS1 expression in human leukemia, we examined the presence of histone modifications that are associated with gene activation in a panel of 8 leukemia cell lines. In MEIS1-expressing cells, but not MEIS1 transcript-negative cell lines, the genomic region corresponding to enhancer EX showed extensive H3K4 mono-methylation (me1H3K4), a hallmark of active distal enhancers. When endogenous MEIS1 expression decreases during cellular differentiation, the active histone mark me1H3K4 was replaced by repressive H3K27 methylation and the associated EZH2 polycomb protein at the EX region. In murine leukemia models, retroviral integration at the Meis1 locus has been shown to result in overexpression of Meis1 leading to development of AML. Strikingly, we found that viral integration frequently occurred within the genomic sequence corresponding to enhancer EX. Collectively, these data suggest that enhancer EX plays an important role in maintaining high level expression of endogenous MEIS1 in transformed leukemic cells. In an effort to identify the molecular basis underlying the observed regulatory function of EX, we found MEIS1 and HOXA9 synergistically stimulate the enhancer activity of EX in reporter gene assays, suggesting that production of MEIS1 protein can reinforce its own expression. Mutation of a conserved site within the enhancer abolished the ability of these two factors to activate reporter gene expression. Using ChIP (Chromatin Immunoprecipitation), we further demonstrated that MEIS1 and HOXA9 specifically bind to the genomic region containing the conserved site in vivo, and the presence of these two factors in the region is associated with active MEIS1 expression. These studies provide insight on the molecular mechanisms controlling transcription regulation of MEIS1, suggesting that overexpression of MEIS1 in acute leukemia is sustained by an autoregulatory loop mediated through a distal enhancer element.

Vitamin K2 induces non-apoptotic cell death along with autophagosome formation in breast cancer cell lines

Breast Cancer ◽  
2019 ◽  
Vol 27 (2) ◽  
pp. 225-235
Author(s):  
Shinsuke Miyazawa ◽  
Shota Moriya ◽  
Hiroko Kokuba ◽  
Hirotsugu Hino ◽  
Naoharu Takano ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Apoptotic Cell ◽  
Cancer Cell Lines ◽  
Vitamin K2 ◽  
Breast Cancer Cell Lines ◽  
Autophagosome Formation

CSIG-22. Cd95l/Cd95 GENE DELETION DECREASES MOUSE GLIOMA TUMORIGENESIS THROUGH THE INHIBITION OF NON-CANONICAL CD95L/CD95-MEDIATED CELL GROWTH AND IMMUNOSUPPRESSION

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi37-vi38
Author(s):  
Clara Quijano-Rubio ◽  
Michael Weller
Keyword(s):  
Cell Death ◽  
Cell Growth ◽  
Cell Lines ◽  
Cancer Cell ◽  
Apoptotic Cell ◽  
Immune Effector ◽  
Immunodeficient Mice ◽  
Murine Glioma

Abstract CD95 is a transmembrane receptor with potential to promote both cell death and growth. Initially described to trigger apoptosis upon ligand (CD95L) engagement, CD95 may also prompt cell proliferation, invasion and stemness. CD95 stimulation to induce cancer cell apoptosis has been proved clinically impracticable. However, in tumors expressing both CD95 and CD95L, strategically inhibiting CD95-CD95L interactions to simultaneously block cancer cell growth and apoptotic cell death in tumor microenvironment components, including CD95-expressing antitumor immune effector cells, may represent an alternative therapeutic strategy. Here we characterized the expression of CD95 and CD95L in murine glioma models in vitro and in vivo. To fully disrupt CD95-CD95L interactions, we deleted Cd95 or Cd95l by CRISPR-Cas9-mediated knockout (KO) and assessed the consequences on cell growth and tumorigenicity in immunocompetent and immunocompromised mice. CD95 expression was identified in selected murine glioma cell lines. In vitro, expression of the canonical, membrane-bound, form of CD95L was not detected but cell lines expressed a shorter non-canonical, soluble, Cd95l variant. Tumors generated upon implantation of the same cells in vivo expressed both Cd95l variants. Upon Cd95l KO, all investigated cell lines exhibited reduced growth in vitro. Cell growth reduction upon Cd95 KO in SMA-497 murine glioma cells was rescued upon Cd95 re-transfection, validating CD95 specificity of the phenotype. Cd95-overexpression in Cd95-expressing cells did not increase growth. In vivo, Cd95 or Cd95l KO cell implantation in syngeneic mice generated smaller tumors than wildtype cells, resulting in prolonged survival. While 40% Cd95l KO cell-implanted immunocompetent mice did not develop tumors, all immunodeficient mice did. Altogether, these data reveal a growth-promoting role of non-canonical CD95L-CD95 interactions in murine gliomas, which blockade through gene KO results in decreased tumorigenicity. Furthermore, our data suggest the contribution of CD95L-mediated immunosuppression to the reduction of Cd95l KO-associated tumorigenicity.

scholarly journals Reclassifying Hepatic Cell Death during Liver Damage: Ferroptosis—A Novel Form of Non-Apoptotic Cell Death?

2020 ◽  
Vol 21 (5) ◽  
pp. 1651 ◽  
Author(s):  
Ricardo U. Macías-Rodríguez ◽  
María Eugenia Inzaugarat ◽  
Astrid Ruiz-Margáin ◽  
Leonard J. Nelson ◽  
Christian Trautwein ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Liver Fibrosis ◽  
Liver Damage ◽  
Kidney Diseases ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Apoptotic Cell Death ◽  
Antioxidant Systems ◽  
Different Types

Ferroptosis has emerged as a new type of cell death in different pathological conditions, including neurological and kidney diseases and, especially, in different types of cancer. The hallmark of this regulated cell death is the presence of iron-driven lipid peroxidation; the activation of key genes related to this process such as glutathione peroxidase-4 (gpx4), acyl-CoA synthetase long-chain family member-4 (acsl4), carbonyl reductase [NADPH] 3 (cbr3), and prostaglandin peroxidase synthase-2 (ptgs2); and morphological changes including shrunken and electron-dense mitochondria. Iron overload in the liver has long been recognized as both a major trigger of liver damage in different diseases, and it is also associated with liver fibrosis. New evidence suggests that ferroptosis might be a novel type of non-apoptotic cell death in several liver diseases including non-alcoholic steatohepatitis (NASH), alcoholic liver disease (ALD), drug-induced liver injury (DILI), viral hepatitis, and hemochromatosis. The interaction between iron-related lipid peroxidation, cellular stress signals, and antioxidant systems plays a pivotal role in the development of this novel type of cell death. In addition, integrated responses from lipidic mediators together with free iron from iron-containing enzymes are essential to understanding this process. The presence of ferroptosis and the exact mechanisms leading to this non-apoptotic type of cell death in the liver remain scarcely elucidated. Recognizing ferroptosis as a novel type of cell death in the liver could lead to the understanding of the complex interaction between different types of cell death, their role in progression of liver fibrosis, the development of new biomarkers, as well as the use of modulators of ferroptosis, allowing improved theranostic approaches in the clinic.

scholarly journals The Dicyano Compound Induces Autophagic or Apoptotic Cell Death Via Twıst/C-Myc Axis Depending on Metastatic Characteristics of Breast Cancer Cells

2021 ◽  
Author(s):  
Ozge ALVUR ◽  
Hakan KUCUKSAYAN ◽  
Yasemin BAYGU ◽  
Nilgun KABAY ◽  
Yasar GOK ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Cell Lines ◽  
Epithelial To Mesenchymal Transition ◽  
Apoptotic Cell ◽  
Treatment Strategies ◽  
Breast Cancer Cell Lines ◽  
Mesenchymal Transition ◽  
Cancer Subtypes ◽  
Mcf 7

Abstract Breast cancer is a heterogeneous disease which has distinct subtypes and therefore development of novel targeting treatments to fight aganist breast cancer is needed. Although autophagy and apoptosis considered as the major programmed cell death mechanisms are among the current target mechanisms, there are some difficulties in clinical treatment such as the development of drug resistance and cancer recurrence. Therefore it is important that illumination of distinctive mechanisms between cancer types for development novel treatment strategies. In this study, we examined the anti-proliferative effects of the triazole linked galactose substituted dicyano compound (hereafter referred to as the dicyano compound (the DC)) on two different breast cancer cell lines, MDA-MB-231 and MCF-7. We determined that response of each cell lines to the DC was different, since autophagy was induced in MDA-MB-231 and apoptosis was induced in MCF-7. For this reason, we hypothesized that these different responses may be due to the different characteristics of the cells and evaluated effects of aggresiveness degrees of both cell lines on response to the DC. As a result of our analysis, we determined that c-Myc regulation in both cell lines was different upon the DC treatment depending on expression of Twist, an epithelial-to-mesenchymal transition (EMT) mediator. Therefore, we suggest that Twist/c-Myc axis may have a role in different response to the DC-induced cell death pathways in breast cancer subtypes.

scholarly journals Ginsenoside Rg1 Induces Apoptotic Cell Death in Triple-Negative Breast Cancer Cell Lines and Prevents Carcinogen-Induced Breast Tumorigenesis in Sprague Dawley Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yan Chu ◽  
Wentao Zhang ◽  
G. Kanimozhi ◽  
G. R. Brindha ◽  
Defu Tian
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Cell Lines ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Apoptotic Cell ◽  
Experimental Models ◽  
Apoptotic Cell Death ◽  
Breast Cancer Cell Lines ◽  
Ginsenoside Rg1

The objective of this study is to investigate the anticancer potential of ginsenoside Rg1 using in vitro and in vivo experimental models. In this study, we found that ginsenoside Rg1 induces cytotoxicity and apoptotic cell death through reactive oxygen species (ROS) generation and alterations in mitochondrial membrane potential (MMP) in the triple-negative breast cancer cells (MDA-MB-MD-231 cell lines). We found that ginsenoside Rg1 induces the formation of gamma H2AX foci, an indication of DNA damage, and subsequent TUNEL positive apoptotic nuclei in the MDA-MB-MD-231 cell lines. Further, we found that ginsenoside Rg1 prevents 7,12-dimethylbenz (a) anthracene (DMBA; 20 mg/rat) induced mammary gland carcinogenesis in experimental rats. We observed oral administration of ginsenoside Rg1 inhibited the DMBA-mediated tumor incidence, prevented the elevation of oxidative damage markers, and restored antioxidant enzymes near to normal. Furthermore, qRT-PCR gene expression studies revealed that ginsenoside Rg1 prevents the expression of markers associated with cell proliferation and survival, modulates apoptosis markers, downregulates invasion and angiogenesis markers, and regulates the EMT markers. Therefore, the present results suggest that ginsenoside Rg1 shows significant anticancer properties against breast cancer in experimental models.

scholarly journals BRD4 modulates vulnerability of triple-negative breast cancer to targeting of integrin-dependent signaling pathways

2020 ◽  
Vol 43 (6) ◽  
pp. 1049-1066
Author(s):  
Yang Zhang ◽  
Bingwei Xu ◽  
Junfeng Shi ◽  
Jieming Li ◽  
Xinlan Lu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Clinical Outcomes ◽  
Cell Lines ◽  
Cancer Cell ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Therapeutic Potential ◽  
Apoptotic Cell ◽  
Xenograft Model

Abstract Purpose Stemming from a myriad of genetic and epigenetic alterations, triple-negative breast cancer (TNBC) is tied to poor clinical outcomes and aspires for individualized therapies. Here we investigated the therapeutic potential of co-inhibiting integrin-dependent signaling pathway and BRD4, a transcriptional and epigenetic mediator, for TNBC. Methods Two independent patient cohorts were subjected to bioinformatic and IHC examination for clinical association of candidate cancer drivers. The efficacy and biological bases for co-targeting these drivers were interrogated using cancer cell lines, a protein kinase array, chemical inhibitors, RNAi/CRISPR/Cas9 approaches, and a 4 T1-Balb/c xenograft model. Results We found that amplification of the chromosome 8q24 region occurred in nearly 20% of TNBC tumors, and that it coincided with co-upregulation or amplification of c-Myc and FAK, a key effector of integrin-dependent signaling. This co-upregulation at the mRNA or protein level correlated with a poor patient survival (p < 0.0109 or p < 0.0402, respectively). Furthermore, we found that 14 TNBC cell lines exhibited high vulnerabilities to the combination of JQ1 and VS-6063, potent pharmacological antagonists of the BRD4/c-Myc and integrin/FAK-dependent pathways, respectively. We also observed a cooperative inhibitory effect of JQ1 and VS-6063 on tumor growth and infiltration of Ly6G+ myeloid-derived suppressor cells in vivo. Finally, we found that JQ1 and VS-6063 cooperatively induced apoptotic cell death by altering XIAP, Bcl2/Bcl-xl and Bim levels, impairing c-Src/p130Cas-, PI3K/Akt- and RelA-associated signaling, and were linked to EMT-inducing transcription factor Snail- and Slug-dependent regulation. Conclusion Based on our results, we conclude that the BRD4/c-Myc- and integrin/FAK-dependent pathways act in concert to promote breast cancer cell survival and poor clinical outcomes. As such, they represent promising targets for a synthetic lethal-type of therapy against TNBC.

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