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1.
Nucleic Acids Res ; 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39315698

ABSTRACT

Epigenetic aberration is one of the major driving factors in human cancer, often leading to acquired resistance to chemotherapies. Various small molecule epigenetic modulators have been reported. Nonetheless, outcomes from animal models and clinical trials have underscored the substantial setbacks attributed to pronounced on- and off-target toxicities. To address these challenges, CRISPR/dCas9 technology is emerging as a potent tool for precise modulation of epigenetic mechanism. However, this technology involves co-expressing exogenous epigenetic modulator proteins, which presents technical challenges in preparation and delivery with potential undesirable side effects. Recently, our research demonstrated that Cas9 tagged with the Phe-Cys-Pro-Phe (FCPF)-peptide motif can be specifically targeted by perfluorobiphenyl (PFB) derivatives. Here, we integrated the FCPF-tag into dCas9 and established a chemically inducible platform for epigenome editing, called Chem-CRISPR/dCas9FCPF. We designed a series of chemical inhibitor-PFB conjugates targeting various epigenetic modulator proteins. Focusing on JQ1, a panBET inhibitor, we demonstrate that c-MYC-sgRNA-guided JQ1-PFB specifically inhibits BRD4 in close proximity to the c-MYC promoter/enhancer, thereby effectively repressing the intricate transcription networks orchestrated by c-MYC as compared with JQ1 alone. In conclusion, our Chem-CRISPR/dCas9FCPF platform significantly increased target specificity of chemical epigenetic inhibitors, offering a viable alternative to conventional fusion protein systems for epigenome editing.

2.
Eur J Med Chem ; 257: 115513, 2023 Sep 05.
Article in English | MEDLINE | ID: mdl-37253308

ABSTRACT

The identification of small molecules capable of replacing transcription factors has been a longstanding challenge in the generation of human chemically induced pluripotent stem cells (iPSCs). Recent studies have shown that ectopic expression of OCT4, one of the master pluripotency regulators, compromised the developmental potential of resulting iPSCs, This highlights the importance of finding endogenous OCT4 inducers for the generation of clinical-grade human iPSCs. Through a cell-based high throughput screen, we have discovered several new OCT4-inducing compounds (O4Is). In this work, we prepared metabolically stable analogues, including O4I4, which activate endogenous OCT4 and associated signaling pathways in various cell lines. By combining these with a transcription factor cocktail consisting of SOX2, KLF4, MYC, and LIN28 (referred to as "CSKML") we achieved to reprogram human fibroblasts into a stable and authentic pluripotent state without the need for exogenous OCT4. In Caenorhabditis elegans and Drosophila, O4I4 extends lifespan, suggesting the potential application of OCT4-inducing compounds in regenerative medicine and rejuvenation therapy.


Subject(s)
Cellular Reprogramming , Induced Pluripotent Stem Cells , Humans , Kruppel-Like Factor 4 , Induced Pluripotent Stem Cells/metabolism , Transcription Factors/metabolism , Aging , Cell Differentiation
3.
J Med Chem ; 66(6): 3995-4008, 2023 03 23.
Article in English | MEDLINE | ID: mdl-36898000

ABSTRACT

Treatment of triple-negative breast cancer (TNBC) has long been a medical challenge because of the lack of effective therapeutic targets. Targeting lipid, carbohydrate, and nucleotide metabolism pathways has recently been proven as a promising option in view of three heterogeneous metabolic-pathway-based TNBC subtypes. Here, we present a multimodal anticancer platinum(II) complex, named Pt(II)caffeine, with a novel mode of action involving simultaneous mitochondrial damage, inhibition of lipid, carbohydrate, and nucleotide metabolic pathways, and promotion of autophagy. All these biological processes eventually result in a strong suppression of TNBC MDA-MB-231 cell proliferation both in vitro and in vivo. The results indicate that Pt(II)caffeine, influencing cellular metabolism at multiple levels, is a metallodrug with increased potential to overcome the metabolic heterogeneity of TNBC.


Subject(s)
Platinum , Triple Negative Breast Neoplasms , Humans , Platinum/pharmacology , Triple Negative Breast Neoplasms/drug therapy , Triple Negative Breast Neoplasms/metabolism , Caffeine/therapeutic use , Cell Line, Tumor , Carbohydrates/pharmacology , Nucleotides/pharmacology , Lipids/pharmacology , Cell Proliferation , Apoptosis
4.
Cells ; 11(23)2022 Nov 23.
Article in English | MEDLINE | ID: mdl-36496994

ABSTRACT

Availability of oxygen plays an important role in tissue organization and cell-type specific metabolism. It is, however, difficult to analyze hypoxia-related adaptations in vitro because of inherent limitations of experimental model systems. In this study, we establish a microfluidic tissue culture protocol to generate hypoxic gradients in vitro, mimicking the conditions found in the liver acinus. To accomplish this, four microfluidic chips, each containing two chambers, were serially connected to obtain eight interconnected chambers. HepG2 hepatocytes were uniformly seeded in each chamber and cultivated under a constant media flow of 50 µL/h for 72 h. HepG2 oxygen consumption under flowing media conditions established a normoxia to hypoxia gradient within the chambers, which was confirmed by oxygen sensors located at the inlet and outlet of the connected microfluidic chips. Expression of Hif1α mRNA and protein was used to indicate hypoxic conditions in the cells and albumin mRNA and protein expression served as a marker for liver acinus-like zonation. Oxygen measurements performed over 72 h showed a change from 17.5% to 15.9% of atmospheric oxygen, which corresponded with a 9.2% oxygen reduction in the medium between chamber1 (inlet) and 8 (outlet) in the connected microfluidic chips after 72 h. Analysis of Hif1α expression and nuclear translocation in HepG2 cells additionally confirmed the hypoxic gradient from chamber1 to chamber8. Moreover, albumin mRNA and protein levels were significantly reduced from chamber1 to chamber8, indicating liver acinus zonation along the oxygen gradient. Taken together, microfluidic cultivation in interconnected chambers provides a new model for analyzing cells in a normoxic to hypoxic gradient in vitro. By using a well-characterized cancer cell line as a homogenous hepatocyte population, we also demonstrate that an approximate 10% reduction in oxygen triggers translocation of Hif1α to the nucleus and reduces albumin production.


Subject(s)
Liver , Oxygen , Humans , Oxygen/metabolism , Liver/metabolism , Hypoxia/metabolism , RNA, Messenger/metabolism , Albumins/metabolism
5.
Cells ; 11(23)2022 Nov 30.
Article in English | MEDLINE | ID: mdl-36497120

ABSTRACT

Targeting cancer metabolism has become one of the strategies for a rational anti-tumor therapy. However, cellular plasticity, driven by a major regulator of cellular growth and metabolism, mTORC1, often leads toward treatment resistance. Sestrin2, a stress-inducible protein, has been described as an mTORC1 inhibitor upon various types of stress signals. Immune assays and online measurements of cellular bioenergetics were employed to investigate the nature of Sestrin2 regulation, and finally, by silencing the SESN2 gene, to identify the role of induced Sestrin2 upon a single amino acid deprivation in cancer cells of various origins. Our data suggest that a complex interplay of either oxidative, energetic, nutritional stress, or in combination, play a role in Sestrin2 regulation upon single amino acid deprivation. Therefore, cellular metabolic background and sequential metabolic response dictate Sestrin2 expression in the absence of an amino acid. While deprivations of essential amino acids uniformly induce Sestrin2 levels, non-essential amino acids regulate Sestrin2 differently, drawing a characteristic Sestrin2 expression fingerprint, which could serve as a first indication of the underlying cellular vulnerability. Finally, we show that canonical GCN2-ATF4-mediated Sestrin2 induction leads to mTORC1 inhibition only in amino acid auxotroph cells, where the amino acid cannot be replenished by metabolic reprogramming.


Subject(s)
Amino Acids , Nuclear Proteins , Mechanistic Target of Rapamycin Complex 1/metabolism , Amino Acids/metabolism , Nuclear Proteins/metabolism , Cell Proliferation
6.
Nat Cancer ; 3(4): 471-485, 2022 04.
Article in English | MEDLINE | ID: mdl-35484422

ABSTRACT

Aberrant expression of MYC transcription factor family members predicts poor clinical outcome in many human cancers. Oncogenic MYC profoundly alters metabolism and mediates an antioxidant response to maintain redox balance. Here we show that MYCN induces massive lipid peroxidation on depletion of cysteine, the rate-limiting amino acid for glutathione (GSH) biosynthesis, and sensitizes cells to ferroptosis, an oxidative, non-apoptotic and iron-dependent type of cell death. The high cysteine demand of MYCN-amplified childhood neuroblastoma is met by uptake and transsulfuration. When uptake is limited, cysteine usage for protein synthesis is maintained at the expense of GSH triggering ferroptosis and potentially contributing to spontaneous tumor regression in low-risk neuroblastomas. Pharmacological inhibition of both cystine uptake and transsulfuration combined with GPX4 inactivation resulted in tumor remission in an orthotopic MYCN-amplified neuroblastoma model. These findings provide a proof of concept of combining multiple ferroptosis targets as a promising therapeutic strategy for aggressive MYCN-amplified tumors.


Subject(s)
Ferroptosis , Neuroblastoma , Cell Death , Child , Cysteine/therapeutic use , Ferroptosis/genetics , Glutathione/therapeutic use , Humans , N-Myc Proto-Oncogene Protein/genetics , Neuroblastoma/genetics
7.
Arch Toxicol ; 96(5): 1483-1487, 2022 05.
Article in English | MEDLINE | ID: mdl-35304627

ABSTRACT

Microfluidic tissue culture and organ-on-a-chip models provide efficient tools for drug testing in vivo and are considered to become the basis of in vitro test systems to analyze drug response, drug interactions and toxicity to complement and reduce animal testing. A major limitation is the efficient recording of drug action. Here we present an efficient experimental setup that allows long-term cultivation of cells in a microfluidic system in combination with continuous recording of luciferase reporter gene expression. The system combines a sensitive cooled luminescence camera system in combination with a custom build miniaturized incubation chamber. The setup allows to monitor time-dependent activation, but also the end of drug response. Repeated activation and recovery as well as varying durations of drug treatment periods can be monitored, and different modes of drug activity can be visualized.


Subject(s)
Microfluidic Analytical Techniques , Microfluidics , Animals , Lab-On-A-Chip Devices
8.
J Cell Biol ; 221(1)2022 01 03.
Article in English | MEDLINE | ID: mdl-34860252

ABSTRACT

Transforming growth factor ß (TGF-ß) signaling plays a fundamental role in metazoan development and tissue homeostasis. However, the molecular mechanisms concerning the ubiquitin-related dynamic regulation of TGF-ß signaling are not thoroughly understood. Using a combination of proteomics and an siRNA screen, we identify pVHL as an E3 ligase for SMAD3 ubiquitination. We show that pVHL directly interacts with conserved lysine and proline residues in the MH2 domain of SMAD3, triggering degradation. As a result, the level of pVHL expression negatively correlates with the expression and activity of SMAD3 in cells, Drosophila wing, and patient tissues. In Drosophila, loss of pVHL leads to the up-regulation of TGF-ß targets visible in a downward wing blade phenotype, which is rescued by inhibition of SMAD activity. Drosophila pVHL expression exhibited ectopic veinlets and reduced wing growth in a similar manner as upon loss of TGF-ß/SMAD signaling. Thus, our study demonstrates a conserved role of pVHL in the regulation of TGF-ß/SMAD3 signaling in human cells and Drosophila wing development.


Subject(s)
Proteolysis , Signal Transduction , Smad3 Protein/metabolism , Transforming Growth Factor beta/metabolism , Von Hippel-Lindau Tumor Suppressor Protein/metabolism , Animals , Drosophila melanogaster/metabolism , HCT116 Cells , HeLa Cells , Humans , Protein Binding , Protein Domains , Smad2 Protein/metabolism , Smad3 Protein/chemistry , Ubiquitin-Protein Ligases/metabolism
9.
Biotechnol J ; 16(8): e2100088, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34008350

ABSTRACT

Great efforts are directed towards improving productivity, consistency and quality of biopharmaceutical processes and products. One particular area is the development of new sensors for continuous monitoring of critical bioprocess parameters by using online or in-line monitoring systems. Recently, we developed a glucose biosensor applicable in single-use, in-line and long-term glucose monitoring in mammalian cell bioreactors. Now, we integrated this sensor in an automated glucose monitoring and feeding system capable of maintaining stable glucose levels, even at very low concentrations. We compared this fed-batch feedback system at both low (< 1 mM) and high (40 mM) glucose levels with traditional batch culture methods, focusing on glycosylation and glycation of the recombinant protein darbepoetin alfa (DPO) produced by a CHO cell line. We evaluated cell growth, metabolite and product concentration under different glucose feeding strategies and show that continuous feeding, even at low glucose levels, has no harmful effects on DPO quantity and quality. We conclude that our system is capable of tight glucose level control throughout extended bioprocesses and has the potential to improve performance where constant maintenance of glucose levels is critical.


Subject(s)
Blood Glucose Self-Monitoring , Blood Glucose , Animals , Batch Cell Culture Techniques , Bioreactors , CHO Cells , Cricetinae , Cricetulus , Darbepoetin alfa , Glucose
10.
Cancer Metab ; 9(1): 5, 2021 Jan 22.
Article in English | MEDLINE | ID: mdl-33482908

ABSTRACT

BACKGROUND: Aerobic glycolysis, discovered by Otto Warburg, is a hallmark of cancer metabolism even though not yet fully understood. The low activity of the cancerous pyruvate kinase isozyme (M2) is thought to play an important role by facilitating the conversion of glycolytic intermediates to other anabolic pathways to support tumors' high proliferation rate. METHODS: Five breast cancer cell lines representing different molecular subtypes were used in this study where real time measurements of cellular bioenergetics and immunoblotting analysis of energy- and nutrient-sensing pathways were employed to investigate the potential effects of PKM2 allosteric activator (DASA-58) in glucose rewiring. RESULTS: In this study, we show that DASA-58 can induce pyruvate kinase activity in breast cancer cells without affecting the overall cell survival. The drug is also able to reduce TXNIP levels (an intracellular glucose sensor) probably through depletion of upstream glycolytic metabolites and independent of AMPK and ER signaling. AMPK shows an induction in phosphorylation (T172) in response to treatment an effect that can be potentiated by combining DASA-58 with other metabolic inhibitors. CONCLUSIONS: Altogether, the multifaceted metabolic reprogramming induced by DASA-58 in breast cancer cells increases their susceptibility to other therapeutics suggesting the suitability of the intracellular glucose sensor TXNIP as a marker of PK activity.

11.
Free Radic Biol Med ; 163: 196-209, 2021 02 01.
Article in English | MEDLINE | ID: mdl-33359260

ABSTRACT

The idea to use megadoses of ascorbate (vitamin C) for cancer treatment has recently been revived. Despite clear efficacy in animal experimentation, our understanding of the cellular and molecular mechanisms of this treatment is still limited and suggests a combined oxidative and metabolic mechanism behind the selective cytotoxicity of ascorbate towards cancerous cells. To gain more insight into the cellular effects of high doses of ascorbate, we performed a detailed analysis of metabolic changes and cell survival of both luminal and basal-like breast cancer cells treated with ascorbate and revealed a distinctive metabolic shift virtually reversing the Warburg effect and triggering a severe disruption of redox homeostasis. High doses of ascorbate were cytotoxic against MCF7 and MDA-MB231 cells representing luminal and basal-like breast cancer phenotypes. Cell death was dependent on ascorbate-induced oxidative stress and accumulation of ROS, DNA damage, and depletion of essential intracellular co-factors including NAD+/NADH, associated with a multifaceted metabolic rewiring. This included a sharp disruption of glycolysis at the triose phosphate level, a rapid drop in ATP levels, and redirection of metabolites toward lipid droplet accumulation and increased metabolites and enzymatic activity in the pentose phosphate pathway (PPP). High doses of ascorbate also inhibited the TCA cycle and increased oxygen consumption. Together the severe disruptions of the intracellular metabolic homeostasis on multiple levels "redox crisis and energetic catastrophe" consequently trigger a rapid irreversible cell death.


Subject(s)
Breast Neoplasms , Animals , Ascorbic Acid/pharmacology , Breast Neoplasms/drug therapy , Cell Survival , Energy Metabolism , Female , Humans , Oxidation-Reduction , Oxidative Stress
12.
Angew Chem Int Ed Engl ; 59(38): 16795-16800, 2020 09 14.
Article in English | MEDLINE | ID: mdl-32529715

ABSTRACT

A novel alkynyl phosphane gold(I) complex (trimethylphosphane)(3-(1,3-dimethylxanthine-7-yl)prop-1-yn-1-yl)gold(I) 1 displayed mutiple biological activites including selective proliferation inhibitory, anti-metastatic, and anti-angiogenic effects. The complex also induced effects related to aneuploidy in HCT-116 colon carcinoma cells, which might be mainly ascribed to the dysfunction of mitochondrial bioenergetics and downregulation of glycolysis. Induction of aneuploidy beyond a critical level can provide an effective strategy to target cancer, in particular colorectal tumours with a low tolerance of aneuploidy, and could be of relevance for 1 and other metallodrugs.


Subject(s)
Aneuploidy , Antineoplastic Agents/pharmacology , Colonic Neoplasms/drug therapy , Organogold Compounds/pharmacology , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Chickens , Chorioallantoic Membrane/drug effects , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , HCT116 Cells , Humans , Molecular Structure , Organogold Compounds/chemical synthesis , Organogold Compounds/chemistry , Ovum/drug effects , Reactive Oxygen Species/metabolism , Structure-Activity Relationship
13.
EBioMedicine ; 54: 102699, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32330875

ABSTRACT

BACKGROUND: The extracellular signal-regulated kinase (ERK) pathway regulates cell growth, and is hyper-activated and associated with drug resistance in hepatocellular carcinoma (HCC). Metabolic pathways are profoundly dysregulated in HCC. Whether an altered metabolic state is linked to activated ERK pathway and drug response in HCC is unaddressed. METHODS: We deprived HCC cells of glutamine to induce metabolic alterations and performed various assays, including metabolomics (with 13C-glucose isotope tracing), microarray analysis, and cell proliferation assays. Glutamine-deprived cells were also treated with kinase inhibitors (e.g. Sorafenib, Erlotinib, U0126 amongst other MEK inhibitors). We performed bioinformatics analysis and stratification of HCC tumour microarrays to determine upregulated ERK gene signatures in patients. FINDINGS: In a subset of HCC cells, the withdrawal of glutamine triggers a severe metabolic alteration and ERK phosphorylation (pERK). This is accompanied by resistance to the anti-proliferative effect of kinase inhibitors, despite pERK inhibition. High intracellular serine is a consistent feature of an altered metabolic state and contributes to pERK induction and the kinase inhibitor resistance. Blocking the ERK pathway facilitates cell proliferation by reprogramming metabolism, notably enhancing aerobic glycolysis. We have identified 24 highly expressed ERK gene signatures that their combined expression strongly indicates a dysregulated metabolic gene network in human HCC tissues. INTERPRETATION: A severely compromised metabolism lead to ERK pathway induction, and primes some HCC cells to pro-survival phenotypes upon ERK pathway blockade. Our findings offer novel insights for understanding, predicting and overcoming drug resistance in liver cancer patients. FUND: DFG, BMBF and Sino-German Cooperation Project.


Subject(s)
Carcinoma, Hepatocellular/metabolism , Drug Resistance, Neoplasm , Liver Neoplasms/metabolism , MAP Kinase Signaling System , Antineoplastic Agents/toxicity , Carcinoma, Hepatocellular/genetics , Cell Proliferation , Hep G2 Cells , Humans , Liver Neoplasms/genetics , Metabolome , Protein Kinase Inhibitors/toxicity , Transcriptome
14.
Commun Biol ; 3: 10, 2020.
Article in English | MEDLINE | ID: mdl-31909202

ABSTRACT

Gold compounds have a long history of use as immunosuppressants, but their precise mechanism of action is not completely understood. Using our recently developed liver-on-a-chip platform we now show that gold compounds containing planar N-heterocyclic carbene (NHC) ligands are potent ligands for the aryl hydrocarbon receptor (AHR). Further studies showed that the lead compound (MC3) activates TGFß1 signaling and suppresses CD4+ T-cell activation in vitro, in human and mouse T cells. Conversely, genetic knockdown or chemical inhibition of AHR activity or of TGFß1-SMAD-mediated signaling offsets the MC3-mediated immunosuppression. In scurfy mice, a mouse model of human immunodysregulation polyendocrinopathy enteropathy X-linked syndrome, MC3 treatment reduced autoimmune phenotypes and extended lifespan from 24 to 58 days. Our findings suggest that the immunosuppressive activity of gold compounds can be improved by introducing planar NHC ligands to activate the AHR-associated immunosuppressive pathway, thus expanding their potential clinical application for autoimmune diseases.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/genetics , Immunosuppression Therapy/methods , Organogold Compounds/immunology , Receptors, Aryl Hydrocarbon/genetics , Signal Transduction/drug effects , Transforming Growth Factor beta1/genetics , Animals , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Survival/drug effects , Hep G2 Cells , Humans , Male , Mice , Receptors, Aryl Hydrocarbon/metabolism , Transforming Growth Factor beta1/metabolism
15.
Front Oncol ; 9: 438, 2019.
Article in English | MEDLINE | ID: mdl-31231607

ABSTRACT

The tumor suppressor p53 has a diverse mutational profile in human malignancies, which is known to influence the potency of various chemotherapeutics, such as platins and anti-metabolites. However, the impact of the mutations in the TP53 gene (coding for p53) on the anti-cancer efficacy of gold complexes remains incompletely understood. We therefore investigated the anti-tumor properties of a gold(I) N-heterocyclic carbene (NHC) complex-termed MC3-in human colorectal cancer (CRC) cell lines encompassing three different p53 variations: HCT116 wild-type (WT), HCT116 p53-/-, and HT-29 (mutant; R273H). MC3 treatment induced intracellular reactive oxygen species (ROS) levels, and p21 expression, leading to cell cycle arrest in all cell lines, regardless of their p53 status. The pro-apoptotic response, however, was found to occur in a p53-dependent manner, with WT p53 harboring cells showing the highest responsiveness. Additionally, p73, which was speculated to substitute p53 in p53-deficient cells, was found to be markedly reduced with MC3 treatment in all the cell lines and knocking down its levels did not impact MC3's anti-tumor effects in HCT116 p53-/- cells. Collectively, our results suggest that this small molecule has anti-cancer properties in the context of deficient or mutant p53 and may therefore have chemotherapeutic potential for clinical application.

16.
Sci Rep ; 9(1): 4616, 2019 03 15.
Article in English | MEDLINE | ID: mdl-30874583

ABSTRACT

Organ-on-chip platforms provide models that allow the representation of human physiological processes in cell-based miniaturized systems. Potential pre-clinical applications include drug testing and toxicity studies. Here we describe the use of a multi-compartment micro-fluidic chip to recapitulate hepatic vitamin D metabolism (vitamin D to 25-hydroxyvitamin D) and renal bio-activation (25-hydroxyvitamin D to 1,25-dihydroxyvitamin D) in humans. In contrast to cultivation in conventional tissue culture settings, on-chip cultivation of HepG2 and RPTEC cells in interconnected chambers, used to mimic the liver and kidneys, respectively, resulted in the enhanced expression of vitamin D metabolizing enzymes (CYP2R1, CYP27B1 and CYP24A1). Pump-driven flow of vitamin D3-containing medium through the microfluidic chip produced eluate containing vitamin D3 metabolites. LC-MSMS showed a strong accumulation of 25-hydroxyvitamin D. The chip eluate induced the expression of differentiation markers in HL-60 (acute myeloid leukemia) cells, assessed by qPCR and FACS analysis, in a manner similar to treatment with reference standards indicating the presence of fully activated 1,25 dihydroxyvitamin D, although the latter was not detected in the eluate by LC-MSMS. Interestingly, 25-hydroxyvitamin D by itself led to weak activation of HL-60 cells suggesting that 25-hydroxyvitamin D is also an active metabolite. Our experiments demonstrate that complex metabolic interactions can be reconstructed outside the human body using dedicated organ-on-chip platforms. We therefore propose that such systems may be used to mimic the in vivo metabolism of various micronutrients and xenobiotics.


Subject(s)
Cholecalciferol/metabolism , Kidney/metabolism , Liver/metabolism , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/metabolism , Activation, Metabolic/physiology , Animals , Cell Line , Cytochrome P-450 Enzyme System/metabolism , HL-60 Cells , Hep G2 Cells , Humans , Lab-On-A-Chip Devices , Microchip Analytical Procedures/methods , Microfluidic Analytical Techniques/methods , Microfluidics/methods , Vitamin D/analogs & derivatives , Vitamin D/metabolism , Vitamins/metabolism
17.
Commun Biol ; 1: 210, 2018.
Article in English | MEDLINE | ID: mdl-30511023

ABSTRACT

Cytotoxic activities of several Golgi-dispersing compounds including AMF-26/M-COPA, brefeldin A and golgicide A have previously been shown to induce autophagy or apoptosis. Here, we demonstrate that these Golgi disruptors also trigger ferroptosis, a non-apoptotic form of cell death characterized by iron-dependent oxidative degradation of lipids. Inhibitors of ferroptosis not only counteract cell death, but they also protect from Golgi dispersal and inhibition of protein secretion in response to several Golgi stress agents. Furthermore, the application of sublethal doses of ferroptosis-inducers such as erastin and sorafenib, low cystine growth conditions, or genetic knockdown of SLC7A11 and GPX4 all similarly protect cells from Golgi stress and lead to modulation of ACSL4, SLC7A5, SLC7A11 or GPX4 levels. Collectively, this study suggests a previously unrecognized function of the Golgi apparatus, which involves cellular redox control and prevents ferroptotic cell death.

18.
Int J Mol Sci ; 19(12)2018 Dec 09.
Article in English | MEDLINE | ID: mdl-30544880

ABSTRACT

The p38 MAPK pathway is known to influence the anti-tumor effects of several chemotherapeutics, including that of organometallic drugs. Previous studies have demonstrated the important role of p38 both as a regulator and a sensor of cellular reactive oxygen species (ROS) levels. Investigating the anti-cancer properties of novel 1,8-naphthalimide derivatives containing Rh(I) and Ru(II) N-heterocyclic carbene (NHC) ligands, we observed a profound induction of ROS by the complexes, which is most likely generated from mitochondria (mtROS). Further analyses revealed a rapid and consistent activation of p38 signaling by the naphthalimide-NHC conjugates, with the Ru(II) analogue-termed MC6-showing the strongest effect. In view of this, genetic as well as pharmacological inhibition of p38α, attenuated the anti-proliferative and pro-apoptotic effects of MC6 in HCT116 colon cancer cells, highlighting the involvement of this signaling molecule in the compound's toxicity. Furthermore, the influence of MC6 on p38 signaling appeared to be dependent on ROS levels as treatment with general- and mitochondria-targeted anti-oxidants abrogated p38 activation in response to MC6 as well as the molecule's cytotoxic- and apoptogenic response in HCT116 cells. Altogether, our results provide new insight into the molecular mechanisms of naphthalimide-metal NHC analogues via the ROS-induced activation of p38 MAPK, which may have therapeutic interest for the treatment of various cancer types.


Subject(s)
Apoptosis/drug effects , Colorectal Neoplasms/pathology , Heterocyclic Compounds/pharmacology , Methane/analogs & derivatives , Naphthalimides/pharmacology , Reactive Oxygen Species/metabolism , Ruthenium/pharmacology , p38 Mitogen-Activated Protein Kinases/metabolism , Cell Cycle/drug effects , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Colorectal Neoplasms/metabolism , Heterocyclic Compounds/chemistry , Humans , Ligands , Membrane Potential, Mitochondrial/drug effects , Methane/chemistry , Methane/pharmacology , Mitochondria/drug effects , Mitochondria/metabolism , Naphthalimides/chemistry , Ruthenium/chemistry , Signal Transduction/drug effects
19.
J Exp Clin Cancer Res ; 37(1): 267, 2018 11 02.
Article in English | MEDLINE | ID: mdl-30388963

ABSTRACT

In the publication of this article (1), there is an error in Fig. 5b. This has now been updated in the original article (1).

20.
J Exp Clin Cancer Res ; 37(1): 211, 2018 Sep 03.
Article in English | MEDLINE | ID: mdl-30176945

ABSTRACT

BACKGROUND: Although metabolism is profoundly altered in human liver cancer, the extent to which experimental models, e.g. cell lines, mimic those alterations is unresolved. Here, we aimed to determine the resemblance of hepatocellular carcinoma (HCC) cell lines to human liver tumours, specifically in the expression of deregulated metabolic targets in clinical tissue samples. METHODS: We compared the overall gene expression profile of poorly-differentiated (HLE, HLF, SNU-449) to well-differentiated (HUH7, HEPG2, HEP3B) HCC cell lines in three publicly available microarray datasets. Three thousand and eighty-five differentially expressed genes in ≥2 datasets (P < 0.05) were used for pathway enrichment and gene ontology (GO) analyses. Further, we compared the topmost gene expression, pathways, and GO from poorly differentiated cell lines to the pattern from four human HCC datasets (623 tumour tissues). In well- versus poorly differentiated cell lines, and in representative models HLE and HUH7 cells, we specifically assessed the expression pattern of 634 consistently deregulated metabolic genes in human HCC. These data were complemented by quantitative PCR, proteomics, metabolomics and assessment of response to thirteen metabolism-targeting compounds in HLE versus HUH7 cells. RESULTS: We found that poorly-differentiated HCC cells display upregulated MAPK/RAS/NFkB signaling, focal adhesion, and downregulated complement/coagulation cascade, PPAR-signaling, among pathway alterations seen in clinical tumour datasets. In HLE cells, 148 downregulated metabolic genes in liver tumours also showed low gene/protein expression - notably in fatty acid ß-oxidation (e.g. ACAA1/2, ACADSB, HADH), urea cycle (e.g. CPS1, ARG1, ASL), molecule transport (e.g. SLC2A2, SLC7A1, SLC25A15/20), and amino acid metabolism (e.g. PHGDH, PSAT1, GOT1, GLUD1). In contrast, HUH7 cells showed a higher expression of 98 metabolic targets upregulated in tumours (e.g. HK2, PKM, PSPH, GLUL, ASNS, and fatty acid synthesis enzymes ACLY, FASN). Metabolomics revealed that the genomic portrait of HLE cells co-exist with profound reliance on glutamine to fuel tricarboxylic acid cycle, whereas HUH7 cells use both glucose and glutamine. Targeting glutamine pathway selectively suppressed the proliferation of HLE cells. CONCLUSIONS: We report a yet unappreciated distinct expression pattern of clinically-relevant metabolic genes in HCC cell lines, which could enable the identification and therapeutic targeting of metabolic vulnerabilities at various liver cancer stages.


Subject(s)
Carcinoma, Hepatocellular/genetics , Gene Expression Regulation, Neoplastic/genetics , Liver Neoplasms/genetics , Neoplasm Proteins/genetics , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Hep G2 Cells , Humans , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Signal Transduction/genetics , Transcriptome/genetics
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