Selective abrogation of S6K2 maps lipid homeostasis as a survival vulnerability in MAPKi-resistant NRASmut melanoma

Although oncogenic NRAS activates MAPK signaling, inhibition of the MAPK pathway is not therapeutically efficacious in NRAS-mutant tumors. Here we report that silencing the ribosomal protein S6 kinase 2 (S6K2), while preserving the activity of S6K1, perturbs lipid metabolism, enhances fatty acid unsaturation, triggers lipid peroxidation and induces cell death selectively in NRAS-mutant melanoma cells that are resistant to MAPK inhibition. S6K2 depletion stimulates SREBP1 activity in an S6K1-dependent manner and relieves suppression of PPARα, triggering apoptosis and ferroptosis. Combining PPARα agonists and polyunsaturated fatty acids phenocopies the effects of S6K2 abrogation, blocking tumor growth. Collectively, our study establishes S6K2 and its effector subnetwork as promising targets for NRAS-mutant melanoma that are resistant to global MAPK pathway inhibitors.

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Mannose Metabolism Is a Metabolic Vulnerability Unveiled By Standard and Novel Therapies in Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2021-148489 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 508-508

Author(s):

Keith Woodley ◽

Laura S Dillingh ◽

George Giotopoulos ◽

Pedro Madrigal ◽

Konstantinos Tzelepis ◽

...

Keyword(s):

Lipid Peroxidation ◽

Fatty Acids ◽

Cell Death ◽

Acute Myeloid Leukemia ◽

Fatty Acid ◽

Myeloid Leukemia ◽

Novel Therapies ◽

Mannose Metabolism ◽

Acute Myeloid

Abstract Introduction The development of resistance to standard and novel therapies remains the main obstacle to cure in acute myeloid leukemia (AML). Metabolic rewiring has emerged as a therapeutically actionable vulnerability in AML, where specific metabolic adaptations arising as a result of driver mutations or in response to therapy have been reported. Mannose phosphoisomerase (MPI) is the first enzyme in the mannose metabolism (MM) pathway, that leads to the production of GDP-Mannose, a key sugar donor for N-glycosylation reactions. MPI was amongst the top drop-out genes in our published CRISPR-Cas9 screen aiming to identify sensitizers to FLT3 tyrosine kinase inhibitors (TKI) in AML carrying activating FLT3 internal tandem duplication (ITD) mutations (Gallipoli et al., Blood 2018). Moreover, analysis of published genomic datasets indicates that MPI expression levels are higher in AML compared to normal samples, correlate with patient outcome (A) and further increase in paired relapsed to diagnosis samples. We therefore hypothesized that MM and MPI inhibition sensitize AML cells to both FLT3-TKI and standard chemotherapy and tested this in preclinical models. Methods Experiments were performed in human AML cell lines, primary AML mononuclear cells and normal CD34 + stem/progenitor cells. Liquid chromatography coupled to mass spectrometry and oxygen consumption/extracellular acidification rate as measured by a Seahorse analyser were employed to assess metabolic changes. Gene-expression was measured by RNA-sequencing and confirmed by RT-qPCR. Viability, surface protein expression and lipid peroxidation were assessed by flow-cytometry. Protein expression and localisation was measured by western blot and immunofluorescence. Gene silencing was performed using CRISPR-Cas9 gene editing and inducible short hairpin RNA interference. Results We show that genetic and chemical MPI inhibition sensitizes FLT3 WT and FLT3 ITD AML cell lines in vitro to standard cytarabine chemotherapy and FLT3-TKI respectively and these effects are rescued by the addition of MPI downstream product mannose. We validate these findings in vivo using MPI knock-out (KO) cell line xenografts and in vitro using primary AML samples following MPI knock-down (B). We also demonstrate a lack of toxicity to normal CD34 + cells. Surprisingly, global metabolomic analysis show that MPI KO cells accumulate fatty acids and particularly polyunsaturated fatty acids (PUFA) (C), due to both increased uptake and reduced fatty acid oxidation (FAO). MPI KO cells downregulate several FAO metabolism genes and this is corroborated by the strong positive correlation of MPI expression levels with multiple genes involved in FAO across multiple primary AML datasets. Metabolic profiling demonstrates that MPI KO cells have reduced oxidative phosphorylation metabolism and in particular are unable to oxidise palmitate, an effect rescued by mannose or the FAO activator fenofibrate (D). We link this metabolic defect to the specific activation of the ATF6 arm of the unfolded protein response (UPR) due to a reduction in protein glycosylation in MPI KO cells. We validate this by demonstrating that activating or inhibiting ATF6 respectively phenocopies or rescues the effects of MPI KO (E) and show this to be secondary to ATF6 driving FAO inhibition, via transcriptional downregulation of PPARα, a master regulator of lipid catabolism. Finally, we show that accumulation of PUFA in MPI KO cells is accompanied by reduced cysteine levels and increased markers of oxidative stress and lipid peroxidation, such as 4-hydroxynonenal (4-HNE), all features associated with ferroptosis (F). We validate this by showing that combining FLT3-TKI with MPI KO leads to ferroptotic cell death in AML cells, which can be rescued by the radical-trapping antioxidant ferrostatin. Conclusions We provide further evidence to support the role of metabolic rewiring in driving therapy resistance in AML and show for the first time that targeting MPI and MM sensitizes AML cells to cytarabine and FLT3-TKI. Mechanistically we unveil a novel connection between MM and fatty acid metabolism, via activation of the ATF6 arm of the UPR, leading to cellular PUFA accumulation, lipid peroxidation and ferroptotic cell death. Finally, our findings also suggest that triggering ferroptosis can be leveraged as a therapeutically actionable mechanism driving cell death in therapy-resistant AML cells. Figure 1 Figure 1. Disclosures Vassiliou: Kymab Ltd: Divested equity in a private or publicly-traded company in the past 24 months; STRM.BIO: Consultancy; Astrazeneca: Consultancy.

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Association Between S6K1 Phosphorylation and Cytotoxic Efficacy Of S6K1 Inhibitors

Blood ◽

10.1182/blood.v122.21.5576.5576 ◽

2013 ◽

Vol 122 (21) ◽

pp. 5576-5576

Author(s):

Hongqi Liu ◽

Catherine A. Gallo ◽

David R. Plas

Keyword(s):

Cell Death ◽

Fatty Acid ◽

Programmed Cell Death ◽

Kinase Activity ◽

Conflicts Of Interest ◽

Previous Analysis ◽

Acid Oxidation ◽

S6 Kinase ◽

Ribosomal Protein S6 ◽

Chemotherapeutic Approach

Abstract S6K1 (ribosomal protein S6 Kinase 1) is emerging as a potential target for counteracting the glucose-dependent survival programs induced by oncogenes. In PTEN-deficient cells, previous analysis revealed that inactivating S6K1 was sufficient to reduce glycolysis and induce programmed cell death. In BCR-ABL+ cells, we found that S6K1 inactivation was cytotoxic when combined with a fatty acid oxidation inhibitor. To begin to translate these findings, we have investigated the cytotoxic efficacy of a panel of S6K1 inhibitors. Although all compounds were efficient inhibitors of S6K1 phosphorylation of downstream substrates, there was one class of inhibitors that strongly induced the phosphorylation of S6K1 itself. These inhibitors were not cytotoxic for PTEN-deficient cells. In contrast, inhibitors that avoided strong phosphorylation of S6K1 overcame the pro-survival program in PTEN-deficient cells. These results suggest that S6K1 inhibition may be beneficial as a chemotherapeutic approach, but that inhibitors should be selected to avoid the phosphorylation of S6K1 itself while also inhibiting kinase activity. Disclosures: No relevant conflicts of interest to declare.

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Antimetastatic Effects of Sesamin on Human Head and Neck Squamous Cell Carcinoma through Regulation of Matrix Metalloproteinase-2

Molecules ◽

10.3390/molecules25092248 ◽

2020 ◽

Vol 25 (9) ◽

pp. 2248 ◽

Cited By ~ 1

Author(s):

Jian-Ming Chen ◽

Pei-Yin Chen ◽

Chia-Chieh Lin ◽

Ming-Chang Hsieh ◽

Jen-Tsun Lin

Keyword(s):

Oral Cancer ◽

Matrix Metalloproteinase ◽

Head And Neck ◽

Mapk Pathway ◽

Human Head ◽

Mapk Signaling ◽

Matrix Metalloproteinase 2 ◽

Migration And Invasion ◽

Dependent Manner

Background: Sesamin is a lignin present in sesame oil from the bark of Zanthoxylum spp. Sesamin reportedly has anticarcinogenic potential and exerts anti-inflammatory effects on several tumors. Hypothesis/Purpose: However, the effect of sesamin on metastatic progression in human head and neck squamous carcinoma (HNSCC) remains unknown in vitro and in vivo; hence, we investigated the effect of sesamin on HNSCC cells in vitro. Methods and Results: Sesamin-treated human oral cancer cell lines FaDu, HSC-3, and Ca9-22 were subjected to a wound-healing assay. Furthermore, Western blotting was performed to assess the effect of sesamin on the expression levels of matrix metalloproteinase (MMP)-2 and proteins of the MAPK signaling pathway, including p-ERK1/2, P-p38, and p-JNK1/2. In addition, we investigated the association between MMP-2 expression and the MAPK pathway in sesamin-treated oral cancer cells. Sesamin inhibited cell migration and invasion in FaDu, Ca9-22, and HSC-3 cells and suppressed MMP-2 at noncytotoxic concentrations (0 to 40 μM). Furthermore, sesamin significantly reduced p38 MAPK and JNK phosphorylation in a dose-dependent manner in FaDu and HSC-3 cells. Conclusions: These results indicate that sesamin suppresses the migration and invasion of HNSCC cells by regulating MMP-2 and is thus a potential antimetastatic agent for treating HNSCC.

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The adipose tissue triglyceride lipase ATGL/PNPLA2 is downregulated by insulin and TNF-α in 3T3-L1 adipocytes and is a target for transactivation by PPARγ

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00317.2005 ◽

2006 ◽

Vol 291 (1) ◽

pp. E115-E127 ◽

Cited By ~ 125

Author(s):

Ji Young Kim ◽

Kristin Tillison ◽

Jun-Ho Lee ◽

David A. Rearick ◽

Cynthia M. Smas

Keyword(s):

Adipose Tissue ◽

Ribosomal Protein ◽

Luciferase Reporter ◽

Dependent Manner ◽

S6 Kinase ◽

Triglyceride Lipase ◽

Ribosomal Protein S6 ◽

Tnf Α ◽

Adipose Tissue Triglyceride ◽

Ribosomal Protein S6 Kinase

The minimal adipose phenotype of hormone-sensitive lipase (HSL)-null mice suggested that other hormonally responsive lipase(s) were present in adipocytes. Recent studies have characterized a new adipose tissue triglyceride lipase, ATGL/PNPLA2/destnutrin/iPLA2ζ/TTS2.2 (ATGL). We had previously cloned a novel adipose-enriched transcript by differential screening and recently determined its identity with murine ATGL. We report here on the regulation of ATGL by TNF-α and insulin in 3T3-L1 adipocytes and identify ATGL as a target for transcriptional activation by the key adipogenic transcription factor PPARγ. Insulin at 100 nM resulted in a marked decrease in ATGL transcript that was effectively blocked by inhibitors for PI 3-kinase and p70 ribosomal protein S6 kinase. TNF-α treatment decreased ATGL transcript in a time-dependent manner that paralleled TNF-α downregulation of PPARγ with a maximal decrease noted by 6 h. TNF-α effects on ATGL were attenuated by pretreatment with PD-98059, LY-294002, or rapamycin, suggesting involvement of the p44/42 MAP kinase, PI 3-kinase, and p70 ribosomal protein S6 kinase signals. To study transcriptional regulation of ATGL, we cloned 2,979 bp of the murine ATGL 5′-flanking region. Compared with promoterless pGL2-Basic, the −2979/+21 ATGL luciferase construct demonstrated 120- and 40-fold increases in activity in white and brown adipocytes, respectively. Luciferase reporter activities for a series of eight ATGL promoter deletions revealed that the −928/+21, −1738/+21, −1979/+21, and −2979/+21 constructs were transactivated by PPARγ. Our findings identify the novel lipase ATGL to be a target gene for TNF-α and insulin action in adipocytes and reveal that it is subject to transcriptional control by PPARγ-mediated signals.

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The defense response of Caenorhabditis elegans to Cutibacterium acnes SK137 via the TIR-1-p38 MAPK signaling pathway

Bioscience Biotechnology and Biochemistry ◽

10.1093/bbb/zbab218 ◽

2021 ◽

Author(s):

Ayano Tsuru ◽

Yumi Hamazaki ◽

Shuta Tomida ◽

Mohammad Shaokat Ali ◽

Eriko Kage-Nakadai

Keyword(s):

Caenorhabditis Elegans ◽

Signaling Pathway ◽

P38 Mapk ◽

Defense Response ◽

Mapk Pathway ◽

Defense Responses ◽

Mapk Signaling ◽

Dependent Manner ◽

Healthy Skin ◽

Cutibacterium Acnes

Abstract Cutibacterium acnes plays roles in both acne disease and healthy skin ecosystem. We observed that mutations in the tir-1/SARM1 and p38 MAPK cascade genes significantly shortened Caenorhabditis elegans lifespan upon Cutibacterium acnes SK137 infection. Antimicrobial molecules were induced by SK137 in a TIR-1-dependent manner. These results suggest that defense responses against SK137 involve the TIR-1-p38 MAPK pathway in Caenorhabditis elegans.

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Intracerebral Injection of Heme Induces Lipid Peroxidation, Neuroinflammation, and Sensorimotor Deficits

Stroke ◽

10.1161/strokeaha.120.031911 ◽

2021 ◽

Author(s):

Luiz Ricardo C. Vasconcellos ◽

Letícia Martimiano ◽

Danillo Pereira Dantas ◽

Filipe Mota Fonseca ◽

Hilton Mata-Santos ◽

...

Keyword(s):

Lipid Peroxidation ◽

Signaling Pathway ◽

Brain Damage ◽

Autologous Blood ◽

Mapk Signaling ◽

Heme Oxygenase 1 ◽

Dependent Manner ◽

In Vivo Models ◽

Sensorimotor Deficits ◽

The Brain

Background and Purpose: Heme is a red blood cell component released in the brain parenchyma following intracerebral hemorrhage. However, the study of the pathophysiological mechanisms triggered by heme in the brain is hampered by the lack of well-established in vivo models of intracerebral heme injection. This study aims to optimize and characterize a protocol of intrastriatal heme injection in mice, with a focus on the induction of lipid peroxidation, neuroinflammation and, ultimately, sensorimotor deficits. We also evaluated the involvement of NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), an inflammasome sensor, in the behavior deficits induced by heme in this model. Methods: Mice were injected with heme in the striatum for the evaluation of neuroinflammation and brain damage through histological and biochemical techniques. Immunoblot was used to evaluate the expression of proteins involved in heme/iron metabolism and antioxidant responses and the activation of the MAPK (mitogen-activated protein kinase) signaling pathway. For the assessment of neurological function, we followed-up heme-injected mice for 2 weeks using the rotarod, elevated body swing, and cylinder tests. Mice injected with the vehicle (sham), or autologous blood were used as controls. Results: Heme induced lipid peroxidation and inflammation in the brain. Moreover, heme increased the expression of HO-1 (heme oxygenase-1), ferritin, p62, and superoxide dismutase 2, and activated the MAPK signaling pathway promoting pro-IL (interleukin)-1β production and its cleavage to the active form. Heme-injected mice exhibited signs of brain damage and reactive astrogliosis around the injection site. Behavior deficits were observed after heme or autologous blood injection in comparison to sham-operated controls. In addition, behavior deficits and IL-1β production were reduced in Nlrp3 knockout mice in comparison to wild-type mice. Conclusions: Our results show that intracerebral heme injection induces neuroinflammation, and neurological deficits, in an NLRP3-dependent manner, suggesting that this is a feasible model to evaluate the role of heme in neurological disorders.

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EXTH-27. MOLECULAR CHARACTERIZATION AND PRECLINICAL DEVELOPMENT OF NOVEL SMALL MOLECULE INHIBITOR SPECIFIC FOR WILD-TYPE IDH1 FOR FERROPTOSIS INDUCTION IN GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noab196.666 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi169-vi169

Author(s):

Kevin Murnan ◽

Serena Tommasini-Ghelfi ◽

Lisa Hurley ◽

Corey Dussold ◽

Daniel Wahl ◽

...

Keyword(s):

Fatty Acids ◽

Cell Death ◽

Plasma Membrane ◽

Fatty Acid ◽

Unsaturated Fatty Acids ◽

De Novo ◽

De Novo Lipogenesis ◽

Therapeutic Modality ◽

Wild Type ◽

Genetic Ablation

Abstract Increased de novo synthesis, mobilization and uptake of fatty acids are required to provide sufficient lipids for membrane biogenesis in support of rapid tumor cell division and growth. In addition to their structural roles as components of the plasma membrane, fatty acid-derived lipids regulate ferroptotic cell death, a type of programmed cell death, when oxidized by iron-dependent lipoxygenase enzymes. De novo lipogenesis and the defense against oxidative lipid damage require large amounts of cytosolic NADPH. Our group has recently found that HGG up-regulate wild-type Isocitrate dehydrogenase 1 (referred to hereafter as ‘wt-IDH1high HGG’) to generate large quantities of cytosolic NADPH. RNAi-mediated knockdown of wt-IDH1, alone and in combination with radiation therapy (RT), slows the growth of patient-derived HGG xenografts, while overexpression of wt-IDH1 promotes intracranial HGG growth. Isotope tracer and liquid chromatography-based lipidomic studies indicated that wt-IDH1 supports the de novo biosynthesis of mono-unsaturated fatty acids (MUFAs) and promotes the incorporation of monounsaturated phospholipids into the plasma membrane, while displacing polyunsaturated fatty acid (PUFA) phospholipids. In addition, enhanced NADPH production in wt-IDH1high HGG increases glutathione (GSH) level, reduces reactive oxygen species (ROS), activates the phospholipid peroxidase glutathione peroxidase 4 (GPX4)-driven lipid repair pathway, and dampens the accumulation of PUFA-containing lipid peroxides, known executioners of ferroptosis. To pharmacologically target wt-IDH1,we have used and characterized wt-IDH1i-13, a first-in-class competitive α,β-unsaturated enone (AbbVie). wt-IDH1i-13 potently inhibits wt-IDH1 enzymatic activity, by covalently binding to the NADP+ binding pocket. Our data indicate that wt-IDH1i-13 promotes ferroptosis, which can be rescued by pre-treatment of cells with the peroxyl scavenger and ferroptosis inhibitor ferrostatin. wt-IDH1i-13 is brain-penetrant, and similar to genetic ablation, reduces progression and extends the survival of wt-IDH1high HGG bearing mice, alone and in combination with RT. These studies credential to wt-IDH1i-13 as a novel therapeutic modality for the treatment of wt-IDH1 gliomas.

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Abstract 653: Muscle Ring Finger-1 (MuRF1) Expression Shifts Cardiomyocyte Substrate Utilization from Fatty Acids to Glucose

Circulation ◽

10.1161/circ.116.suppl_16.ii_120-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Monte S Willis ◽

Jon Schisler ◽

Holly McDonough ◽

Cam Patterson

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Relative Proportion ◽

Substrate Utilization ◽

Acid Oxidation ◽

Protective Mechanism ◽

Dependent Manner ◽

Dose Dependent

Previous work has suggested that MuRF1, a cardiac-specific protein, regulates metabolism by its interactions with proteins that regulate ATP transport, glycolysis, and the electron transport chain. We recently identified that MuRF1 is cardioprotective in ischemia reperfusion injury. In the current study, we investigated the effects of MuRF1 expression on metabolic substrate utilization and found that MuRF1 shifts substrate utilization from fatty acids to glucose in a dose-dependent manner. Isolated neonatal ventricular cardiomyocytes were treated with an adenovirus expressing MuRF1 (Ad.MuRF1) or GFP (Ad.GFP) at a range of 0–25 MOI (Multiplicity Of Infection). 14C-Oleate or 14C-glucose were added to cells for 1 hour and 14C-CO2 release was determined using the CO2-trapping method. Trapped 14CO2 and acid soluble metabolites were used to calculate total fatty acid oxidation. Cardiomyocytes treated with 5–25 MOI Ad.MuRF1 demonstrated a dose dependent decrease in fatty acid oxidation of 10.5 +/− 2.3(5 MOI), 8.5 +/− 1.9 (10 MOI), 6.6 +/− 1.6 (15 MOI), and 5.1 +/− 1.3 (25 MOI) nmol oleate/mg protein/h. Compared with control cardiomyocytes treated with 5–25 MOI Ad.GFP (average of 5–25 MOI=13.5 +/− 0.7 nmol oleate/mg protein/h), this represents a 22.2%– 62.2% decrease in fatty acid oxidation. Inversely, glucose oxidation increased with increasing MuRF1 expression. Cardiomyocytes infected with 25 MOI Ad.MuRF1 oxidized 184% more glucose (28.9 +/− 4.6 nmol glucose/mg protein/h) compared to control cells treated with 25 MOI Ad.GFP (15.7 +/− 1.3 nmol glucose/mg protein/h). Increasing MuRF1 expression resulted in no net gain or loss of calculated ATP production (1699 +/− 157 vs. 1480 +/− 188 nmol ATP/mg protein/h). The co-utilization of glucose and fatty acids as substrates for the production of ATP allows the heart to adapt to both environmental stress and disease. Increasing the relative proportion of glucose oxidation in relationship to fatty acids is a known protective mechanism during cardiac stress, and may represent one mechanism by which MuRF1 is cardioprotective.

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Intake of ω-6 Polyunsaturated Fatty Acid-Rich Vegetable Oils and Risk of Lifestyle Diseases

Advances in Nutrition ◽

10.1093/advances/nmaa072 ◽

2020 ◽

Vol 11 (6) ◽

pp. 1489-1509

Author(s):

Tetsumori Yamashima ◽

Tsuguhito Ota ◽

Eishiro Mizukoshi ◽

Hiroyuki Nakamura ◽

Yasuhiko Yamamoto ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Fatty Acids ◽

Cell Death ◽

Fatty Acid ◽

Vegetable Oils ◽

Neuronal Death ◽

Cell Degeneration ◽

Fried Foods ◽

Lifestyle Diseases

Abstract Although excessive consumption of deep-fried foods is regarded as 1 of the most important epidemiological factors of lifestyle diseases such as Alzheimer's disease, type 2 diabetes, and obesity, the exact mechanism remains unknown. This review aims to discuss whether heated cooking oil-derived peroxidation products cause cell degeneration/death for the occurrence of lifestyle diseases. Deep-fried foods cooked in ω-6 PUFA-rich vegetable oils such as rapeseed (canola), soybean, sunflower, and corn oils, already contain or intrinsically generate “hydroxynonenal” by peroxidation. As demonstrated previously, hydroxynonenal promotes carbonylation of heat-shock protein 70.1 (Hsp70.1), with the resultant impaired ability of cells to recycle damaged proteins and stabilize the lysosomal membrane. Until now, the implication of lysosomal/autophagy failure due to the daily consumption of ω-6 PUFA-rich vegetable oils in the progression of cell degeneration/death has not been reported. Since the “calpain-cathepsin hypothesis” was formulated as a cause of ischemic neuronal death in 1998, its relevance to Alzheimer's neuronal death has been suggested with particular attention to hydroxynonenal. However, its relevance to cell death of the hypothalamus, liver, and pancreas, especially related to appetite/energy control, is unknown. The hypothalamus senses information from both adipocyte-derived leptin and circulating free fatty acids. Concentrations of circulating fatty acid and its oxidized form, especially hydroxynonenal, are increased in obese and/or aged subjects. As overactivation of the fatty acid receptor G-protein coupled receptor 40 (GPR40) in response to excessive or oxidized fatty acids in these subjects may lead to the disruption of Ca2+ homeostasis, it should be evaluated whether GPR40 overactivation contributes to diverse cell death. Here, we describe the molecular implication of ω-6 PUFA-rich vegetable oil-derived hydroxynonenal in lysosomal destabilization leading to cell death. By oxidizing Hsp70.1, both the dietary PUFA- (exogenous) and the membrane phospholipid- (intrinsic) peroxidation product “hydroxynonenal,” when combined, may play crucial roles in the occurrence of diverse lifestyle diseases including Alzheimer's disease.

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Dihydrochalcone Derivative Induces Breast Cancer Cell Apoptosis via Intrinsic, Extrinsic, and ER Stress Pathways but Abolishes EGFR/MAPK Pathway

BioMed Research International ◽

10.1155/2019/7298539 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18 ◽

Cited By ~ 3

Author(s):

Wasitta Rachakhom ◽

Patompong Khaw-on ◽

Wilart Pompimon ◽

Ratana Banjerdpongchai

Keyword(s):

Breast Cancer ◽

Er Stress ◽

Cell Lines ◽

Cell Apoptosis ◽

Mapk Pathway ◽

Annexin V ◽

Mapk Signaling ◽

Dependent Manner ◽

Induced Apoptosis ◽

Mcf 7

Dihydrochalcone derivatives are active compounds that have been purified from the Thai medicinal plant Cyathostemma argenteum. The objectives of this study were to investigate the effects of two dihydrochalcone derivatives on human breast cancer MDA-MB-231 and MCF-7 cell proliferation and to study the relevant mechanisms involved. The two dihydrochalcone derivatives are 4′,6′-dihydroxy-2′,4-dimethoxy-5′-(2″-hydroxybenzyl)dihydrochalcone (compound 1) and calomelanone (2′,6′-dihydroxy-4,4′-dimethoxydihydrochalcone, compound 2), both of which induced cytotoxicity toward both cell lines in a dose-dependent manner by using MTT assay. Treatment with both derivatives induced apoptosis as determined by annexin V-FITC/propidium iodide employing flow cytometry. The reduction of mitochondrial transmembrane potential (staining with 3,3′-dihexyloxacarbocyanine iodide, DiOC6, employing a flow cytometer) was established in the compound 1-treated cells. Compound 1 induced caspase-3, caspase-8, and caspase-9 activities in both cell lines, as has been determined by specific colorimetric substrates and a spectrophotometric microplate reader which indicated the involvement of both the extrinsic and intrinsic pathways. Calcium ion levels in mitochondrial and cytosolic compartments increased in compound 1-treated cells as detected by Rhod-2AM and Fluo-3AM intensity, respectively, indicating the involvement of the endoplasmic reticulum (ER) stress pathway. Compound 1 induced cell cycle arrest via enhanced atm and atr expressions and by upregulating proapoptotic proteins, namely, Bim, Bad, and tBid. Moreover, compound 1 significantly inhibited the EGFR/MAPK signaling pathway. In conclusion, compound 1 induced MDA-MB-231 and MCF-7 cell apoptosis via intrinsic, extrinsic, and ER stress pathways, whereas it ameliorated the EGFR/MAPK pathway in the MCF-7 cell line. Consequently, it is believed that compound 1 could be effectively developed for cancer treatments.

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