KJJ Endocrinol. 2014 Feb 3. [Epub ahead of print]

Insulin regulates the novel adipokine adipolin/CTRP12: in vivo and ex vivo effects.Tan BK, Lewandowski KC, O'Hare JP, Randeva HS.

Author information

B Tan, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom.

Abstract

There has been intense interest in the adipokines of the C1q complement/TNF-related protein (CTRP) superfamily. Adipolin (CTRP12) has been described as a novel adipokine, abundantly expressed by adipose tissue with insulin sensitizing and anti-inflammatory effects. We wanted to investigate the effects of acute and chronic hyperinsulinaemia on circulating adipolin concentrations (ELISA) via a prolonged insulin-glucose infusion in humans. We also examined the effects of insulin and the insulin sensitizer, rosiglitazone, on adipolin concentrations (western blotting) in human adipose tissue explants. We found that hyperinsulinaemic induction in healthy lean human subjects significantly increased circulating adipolin (P < 0.05, P < 0.01). Furthermore, in subcutaneous adipose tissue explants, insulin significantly increased adipolin protein expression and secretion (P < 0.05, P < 0.01). This effect was attenuated by the phosphatidylinositol 3-kinase inhibitor (PI3K), LY294002 (P < 0.05). Moreover, the insulin sensitizing peroxisome proliferator-activated receptor (PPAR)-γ agonist, rosiglitazone, significantly increased adipolin protein expression and secretion in subcutaneous adipose tissue explants (P < 0.05, P < 0.01). This effect was inhibited by the PPAR-γ antagonist, GW9662 (P < 0.05). Our data provide novel insights into adipolin physiology in human subjects.

PLoS One. 2014 Jan 29;9(1):e86724. doi: 10.1371/journal.pone.0086724. eCollection 2014.

Therapeutic role of ursolic Acid on ameliorating hepatic steatosis and improving metabolic disorders in high-fat diet-induced non-alcoholic Fatty liver disease rats.Li S, Meng F, Liao X, Wang Y, Sun Z, Guo F, Li X, Meng M, Li Y, Sun C.

Author information

Department of Nutrition and Food Hygiene, Harbin Medical University, Harbin, Heilongjiang province, P. R. China.

Abstract

BACKGROUND:

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent liver diseases around the world, and is closely associated with obesity, diabetes, and insulin resistance. Ursolic acid (UA), an

ubiquitous triterpenoid with multifold biological roles, is distributed in various plants. This study was conducted to investigate the therapeutic effect and potential mechanisms of UA against hepatic steatosis in a high-fat diet (HFD)-induced obese non-alcoholic fatty liver disease (NAFLD) rat model.

METHODOLOGY/PRINCIPAL FINDINGS:

Obese NAFLD model was established in Sprague-Dawley rats by 8-week HFD feeding. Therapeutic role of UA was evaluated using 0.125%, 0.25%, 0.5% UA-supplemented diet for another 6 weeks. The results from both morphologic and histological detections indicated that UA significantly reversed HFD-induced hepatic steatosis and liver injury. Besides, hepatic peroxisome proliferator-activated receptor (PPAR)-α was markedly up-regulated at both mRNA and protein levels by UA. Knocking down PPAR-α significantly inhibited the anti-steatosis role of UA in vitro. HFD-induced adverse changes in the key genes, which participated in hepatic lipid metabolism, were also alleviated by UA treatment. Furthermore, UA significantly ameliorated HFD-induced metabolic disorders, including insulin resistance, inflammation and oxidative stress.

CONCLUSIONS/SIGNIFICANCE:

These results demonstrated that UA effectively ameliorated HFD-induced hepatic steatosis through a PPAR-α involved pathway, via improving key enzymes in the controlling of lipids metabolism. The metabolic disorders were accordingly improved with the decrease of hepatic steatosis. Thereby, UA could be a promising candidate for the treatment of NAFLD.

J Immunol. 2014 Jan 31. [Epub ahead of print]

PPAR-γ/IL-10 Axis Inhibits MyD88 Expression and Ameliorates Murine Polymicrobial Sepsis.Ferreira AE, Sisti F, Sônego F, Wang S, Filgueiras LR, Brandt S, Serezani AP, Du H, Cunha FQ, Alves-Filho JC, Serezani CH.

Author information

Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202;

Abstract

Polymicrobial sepsis induces organ failure and is accompanied by overwhelming inflammatory response and impairment of microbial killing. Peroxisome proliferator-activated receptor (PPAR)-γ is a nuclear receptor with pleiotropic effects on lipid metabolism, inflammation, and cell proliferation. The insulin-sensitizing drugs thiazolidinediones (TZDs) are specific PPAR-γ agonists. TZDs exert anti-inflammatory actions in different disease models, including polymicrobial sepsis. The TZD pioglitazone, which has been approved by the U.S. Food and Drug Administration, improves sepsis outcome; however, the molecular programs that mediate its effect have not been determined. In a murine model of sepsis, we now show that pioglitazone treatment improves microbial clearance and enhances neutrophil recruitment to the site of infection. We also observed reduced proinflammatory cytokine production and high IL-10 levels in pioglitazone-treated mice. These effects were associated with a decrease in STAT-1-dependent expression of MyD88 in vivo and in vitro. IL-10R blockage abolished PPAR-γ-mediated inhibition of MyD88 expression. These data demonstrate that the primary mechanism by which pioglitazone protects against polymicrobial sepsis is through the impairment of MyD88 responses. This appears to represent a novel regulatory program. In this regard, pioglitazone

provides advantages as a therapeutic tool, because it improves different aspects of host defense during sepsis, ultimately enhancing survival.

PLoS One. 2014 Jan 30;9(1):e87848.

KDT501, a Derivative from Hops, Normalizes Glucose Metabolism and Body Weight in Rodent Models of Diabetes.Konda VR, Desai A, Darland G, Grayson N, Bland JS.

Gerodontology. 2014 Feb 4.

PPAR γ gene polymorphism, C-reactive protein level, BMI and periodontitis in post- menopausal Japanese women.Wang Y, Sugita N, Yoshihara A, Iwasaki M, Miyazaki H, Nakamura K, Yoshie H.

J Endocrinol. 2014 Feb 3.

Insulin regulates the novel adipokine adipolin/CTRP12: in vivo and ex vivo effects.Tan BK, Lewandowski KC, O'Hare JP, Randeva HS.

J Immunol. 2014 Jan 31.

PPAR -γ/IL-10 Axis Inhibits MyD88 Expression and Ameliorates Murine Polymicrobial Sepsis.Ferreira AE, Sisti F, Sônego F, Wang S, Filgueiras LR, Brandt S, Serezani AP, Du H, Cunha FQ, Alves-Filho JC, Serezani CH.

PLoS One. 2014 Jan 29;9(1):e86724.

Therapeutic role of ursolic Acid on ameliorating hepatic steatosis and improving metabolic disorders in high-fat diet-induced non-alcoholic Fatty liver disease rats.Li S, Meng F, Liao X, Wang Y, Sun Z, Guo F, Li X, Meng M, Li Y, Sun C.

Eur J Pharmacol. 2014 Jan 30.

PPAR δ activation inhibits homocysteine-induced p22^phox expression in EA.hy926 cells through reactive oxygen species/p38MAPK pathway.Xiao GF, Xu SH, Chao Y, Xie LD, Xu CS, Wang HJ.

Eur J Pharmacol. 2014 Jan 29.

Silymarin ameliorates fructose induced insulin resistance syndrome by reducing de novo hepatic lipogenesis in the rat.Prakash P, Singh V, Jain M, Rana M, Khanna V, Barthwal MK, Dikshit M.

NATURE

Nature 506, 39–40 (06 February 2014)

Cancer: Interference identifies immune modulators

Lars Zender

A broad in vivo screen of the effects of specific gene inhibition on the antitumour activity of immune cells in mice bearing melanomas has revealed potential targets for cancer therapy. See Article p.52

Figure 1: Screening for T-cell modulators.

Zhou et al.1 compiled libraries of short hairpin RNA (shRNA) molecules designed to

specifically inhibit the expression of genes expressed by dysfunctional (anergic or

exhausted) CD8+ T cells or of genes encoding cell-signalling enzymes (phosphatases and

kinases). The authors then infected CD8+ T cells with these shRNAs and implanted the cells

into mice bearing melanomas. Seven days later, they isolated T cells from the spleens and

tumours of the mice and compared the relative representation of shRNA molecules in the

two tissues. Those shRNA molecules found to be enriched in the tumour were postulated to

be involved in facilitating T-cell survival or proliferation within the tumours and were selected

for further analysis.

ARTICLES In vivo discovery of immunotherapy targets in the tumour microenvironmento Penghui Zhou, Donald R. Shaffer, Diana A. Alvarez Arias, Yukoh Nakazaki, Wouter Pos+ et al.

A short hairpin RNA screen to identify genes that modify the action of tumour-infiltrating CD8 T cells in tumour-bearing mice pinpointed the phosphatase subunit Ppp2r2d as a new target for tumour therapy; knockdown of Ppp2r2d in T cells enabled their accumulation in tumours and significantly delayed tumour growth.See also News & Views by Zender

An environmental bacterial taxon with a large and distinct metabolic repertoire

o Micheal C. Wilson, Tetsushi Mori, Christian Rückert, Agustinus R. Uria, Maximilian J. Helf+ et al.

Single-cell- and metagenomics-based study reveals two members of the candidate genus ‘Entotheonella’, symbionts of the marine sponge Theonella swinhoei; distinct biosynthetic gene clusters that

account for most of the bioactive polyketides and peptides known from T. swinhoei are shown to be attributable to a single member of the T. swinhoei Y microbiome.See also News & Views by Jaspars & Challis

LETTERS Structure of the SecY channel during initiation of protein translocationo Eunyong Park, Jean-François Ménétret, James C. Gumbart, Steven J. Ludtke, Weikai Li+ et al.

Newly synthesized proteins are targeted to the SecY protein-conducting channel for translocation across the membrane; here, cryo-electron microscopy structures of inactive and active ribosome–channel complexes are presented, revealing that ribosome binding does not result in major structural changes to transmembrane regions of the channel, and that stable channel opening requires loop insertion of the translocating nascent chain.

Structures of the Sec61 complex engaged in nascent peptide translocation or membrane insertion

o Marko Gogala, Thomas Becker, Birgitta Beatrix, Jean-Paul Armache, Clara Barrio-Garcia + et al.

Nascent secretory and membrane proteins are targeted to the Sec61 protein-conducting channel for translocation across or insertion into the endoplasmic reticulum membrane; here cryo-electron microscopy structures of eukaryotic ribosome–channel complexes show how this channel opens vertically during translocation of a secretory protein into the lumen of the endoplasmic reticulum and how it opens laterally during insertion of a transmembrane domain into the lipid bilayer.

Aprataxin resolves adenylated RNA–DNA junctions to maintain genome integrity

o Percy Tumbale, Jessica S. Williams, Matthew J. Schellenberg, Thomas A. Kunkel & R. Scott Williams

This study shows that aprataxin, encoded by a gene mutated in the neurodegenerative disorder AOA1, can remove the 5′ AMP from RNA–DNA junctions; this RNA–DNA damage response promotes cell survival.

Crystal structures of the Lsm complex bound to the 3′ end sequence of U6 small nuclear RNA

o Lijun Zhou, Jing Hang, Yulin Zhou, Ruixue Wan, Guifeng Lu + et al.

The crystal structure of the Lsm protein ring of the U6 small nuclear ribonucleoprotein (snRNP), with and without an RNA comprising the 3′ end of the U6 small nuclear RNA, is solved here; this structure provides insight into the function of U6 snRNP in precursor messenger RNA splicing.

H²J

Original Paper

Cell Death and Differentiation advance online publication 24 January 2014; doi: 10.1038/cdd.2013.198

Fra-2/AP-1 controls adipocyte differentiation and survival by regulating PPARγ and hypoxia

J Luther1,3, K Ubieta1,3, N Hannemann1, M Jimenez2, M Garcia1, C Zech1, G Schett1, E F Wagner2 and A Bozec1

1. 1Department of Internal Medicine 3, University of Erlangen-Nuremberg, Erlangen, Germany2. 2Genes, Development and Disease Group, Cancer Cell Biology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain

Correspondence: A Bozec, Department of Internal Medicine 3 and Institute of Clinical Immunology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany. Tel: +49 9131 8529002; Fax: +49 9131 8529111; E-mail: aline.bozec@uk-erlangen.de

3These authors contributed equally to this work.

Received 11 June 2013; Revised 6 December 2013; Accepted 6 December 2013Advance online publication 24 January 2014

Edited by M Annicchiarico-Petruzzelli

Top of page

Abstract

Adipocyte cell number is a crucial factor for controlling of body weight and metabolic function. The regulation of adipocyte numbers in the adult organism is not fully understood but is considered to depend on the homeostasis of cell differentiation and apoptosis. Herein, we show that targeted deletion of the activator protein (AP-1)-related transcription factor Fra-2 in adipocytes in vivo (Fra-2Δadip mice) induces a high-turnover phenotype with increased differentiation and apoptosis of adipocytes, leading to a decrease in body weight and fat pad mass. Importantly, adipocyte cell numbers were significantly reduced in Fra-2Δadip mice. At the molecular level, Fra-2 directly binds to the PPARγ2 promoter and represses PPARγ2 expression. Deletion of Fra-2 leads to increased PPARγ2 expression and adipocyte differentiation as well as increased adipocyte apoptosis through upregulation of hypoxia-inducible factors (HIFs). These findings suggest that Fra-2 is an important checkpoint to control adipocyte turnover. Therefore, inhibition of Fra-2 may emerge as a useful strategy to increase adipocyte turnover and to reduce adipocyte numbers and fat mass in the body.

Keywords: AP-1/Fra-2; HIFs; adipocyte; apoptosis

Abbreviations: AP-1, activator protein-1; ATF, activating transcription factor; Bad, Bcl-2-associated death promoter; Bax, Bcl-2-associated X protein; Bcl2, B-cell lymphoma 2; Bcl-xl, B-cell lymphoma-extra large; BNIP3, BCL2/adenovirus E1B 19 kDa protein-interacting protein 3; BNIP3L, BCL2/adenovirus E1B 19 kDa protein-interacting protein 3-like; C/EBP, CCAAT/enhancer binding protein; Fabp4, fatty acid binding protein 4; Fra-1, Fos-related antigen 1; Fra-2, Fos-related antigen 2; Glut, glucose transporter; HIF, hypoxia-inducible factor; IBMX, 3-isobutyl-1-methylxanthine; Inos, nitric oxide synthase; MSC, mesenchymal stem cell; PPARγ, peroxisome proliferator-activated receptor-γ; Vegfα, vascular endothelial growth factor α

Original Paper

Cell Death and Differentiation advance online publication 31 January 2014; doi: 10.1038/cdd.2013.200

Smac mimetic promotes glioblastoma cancer stem-like cell differentiation by activating NF-κB

A Tchoghandjian1, C Jennewein1, I Eckhardt1, S Momma2, D Figarella-Branger3 and S Fulda1

1. 1Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Komturstrasse 3a, Frankfurt, Germany2. 2Institute of Neuropathology, Goethe-University, Frankfurt, Germany3. 3INSERM UMR911, Marseille, France

Correspondence: S Fulda, Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Komturstrasse 3a, 60528 Frankfurt, Germany. Tel: +49 69 67866557; Fax: +49 69 6786659157; Email: simone.fulda@kgu.de

Received 21 October 2013; Revised 5 December 2013; Accepted 16 December 2013Advance online publication 31 January 2014

Edited by J Silke

Top of page

Abstract

Recently, a broader role of inhibitor of apoptosis (IAP) proteins besides their antiapoptotic functions has been described. Therefore, we investigated the effect of non-toxic concentrations of the small-molecule Smac mimetic BV6, which antagonizes IAP proteins, on differentiation of cancer stem-like cells (CSLCs) derived from primary glioblastoma (GBM) specimens. Here, we identify a novel function of BV6 in regulating differentiation of GBM CSLCs by activating NF-κB. BV6 at non-lethal doses stimulates morphological changes associated with the differentiation of GBM CSLCs. BV6 increases transcriptional activity, mRNA and protein levels of the astrocytic marker GFAP without altering expression of the neuronal marker β-III-tubulin, indicating that BV6 induces astrocytic differentiation of GBM CSLCs. Molecular studies reveal that BV6 triggers processing of the NF-κB subunit p100 to p52, nuclear translocation of p52 and p50 and increased NF-κB DNA-binding. Intriguingly, inhibition of NF-κB by overexpression of dominant-negative IκBα super-repressor (IκBα-SR) blocks the BV6-stimulated increase in GFAP and differentiation. Interestingly, this BV6-stimulated differentiation is associated with reduced expression of stemness markers such as CD133, Nanog and Sox2 in GBM CSLCs. In contrast, BV6 does not alter cell morphology, differentiation and expression of stemness markers in non-malignant neural stem cells. Importantly, BV6 treatment reduces clonogenicity of GBM CSLCs in vitro and in vivo, suppresses their tumorigenicity in orthotopic and subcutaneous mouse models and significantly increases the survival of mice. By identifying a novel role of BV6 in promoting differentiation of GBM CSLCs, these findings provide new insights into Smac mimetic-regulated non-apoptotic functions with important implications for targeting GBM CSLCs.

Keywords: Smac mimetic; IAP proteins; glioblastoma; NF-κB; differentiation

Abbreviations: bFGF, basic fibroblast growth factor; cIAP, cellular Inhibitor of Apoptosis; CSLCs, cancer stem-like cells; EGF, epidermal growth factor; EMSA, electrophoresis mobility shift assay; GBM, glioblastoma; GFAP, glial fibrillary acidic protein; H&E, hematoxylin and eosin staining; IAP, Inhibitor of Apoptosis; IFN-β, interferon-β; IκBα-SR, IκBα superrepressor; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NF-κB, nuclear factor κB; NIK, NF-κB-inducing kinase; NSCs, neural stem cells; RIP1, receptor-interacting protein 1; TNFR1, tumor necrosis factor receptor 1; TNFα, tumor necrosis factor alpha; TWEAK, tumor necrosis factor-like weak inducer of apoptosis; XIAP, X-linked inhibitor of apoptosis protein

Original Paper

Cell Death and Differentiation advance online publication 31 January 2014; doi: 10.1038/cdd.2014.2

MDM2 restrains estrogen-mediated AKT activation by promoting TBK1-dependent HPIP degradation

K Shostak1,2,9, F Patrascu1,2,9, S I Göktuna1,2, P Close1,2, L Borgs1,3, L Nguyen1,3,4, F Olivier1,5, A Rammal1,2, H Brinkhaus6, M Bentires-Alj6, J-C Marine7,8 and A Chariot1,2,4

1. 1Interdisciplinary Cluster for Applied Genoproteomics, GIGA-Research, University of Liège, Liège, Belgium2. 2Unit of Medical Chemistry, GIGA-Signal Transduction, GIGA-R, University of Liège, Liège, Belgium3. 3Developmental Neurobiology Unit, GIGA-Neurosciences, GIGA-R, University of Liège, Liège, Belgium4. 4Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Wallonia, Belgium5. 5Animal Facility, University of Liege, CHU, Sart-Tilman, Liège 4000, Belgium6. 6Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland7. 7Center for Human Genetics, KU Leuven, Leuven, Belgium8. 8Center for the biology of disease, VIB, KU Leuven, Leuven, Belgium

Correspondence: A Chariot, Laboratory of Clinical Chemistry, GIGA-R, Tour GIGA, +2 B34, Sart-Tilman, University of Liège, CHU, Sart-Tilman, Liège 4000, Belgium. Tel: +32 4 366 2472; Fax: +32 4 366 4534; E-mail: Alain.chariot@ulg.ac.be

9These authors contributed equally to this work.

Received 14 June 2013; Revised 18 December 2013; Accepted 23 December 2013Advance online publication 31 January 2014

Edited by K Vousden

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Abstract

Restoration of p53 tumor suppressor function through inhibition of its interaction and/or enzymatic activity of its E3 ligase, MDM2, is a promising therapeutic approach to treat cancer. However, because the MDM2 targetome extends beyond p53, MDM2 inhibition may also cause unwanted activation of oncogenic pathways. Accordingly, we identified the microtubule-associated HPIP, a positive regulator of oncogenic AKT signaling, as a novel MDM2 substrate. MDM2-dependent HPIP degradation occurs in breast cancer cells on its phosphorylation by the estrogen-activated kinase TBK1. Importantly, decreasing Mdm2 gene dosage in mouse mammary epithelial cells potentiates estrogen-dependent AKT activation owing to HPIP stabilization. In addition, we identified HPIP as a novel p53 transcriptional target, and pharmacological inhibition of MDM2 causes p53-dependent increase in HPIP transcription and also prevents HPIP degradation by turning off TBK1 activity. Our data indicate that p53 reactivation through MDM2 inhibition may result in ectopic AKT oncogenic activity by maintaining HPIP protein levels.

Keywords: TBK1; AKT; HPIP; MDM2; estrogens

Abbreviations: CAS, Cellular apoptosis susceptibility; EGF, Epithelial growth factor; ERα, Estrogen receptor alpha; GREB1, Growth regulation by estrogen in breast cancer 1; FOXO3a, Forkhead box O3; HPIP, Microtubule-binding protein hematopoietic PBX-interaction protein; HUWE1, HECT, UBA and WWE domain-containing protein 1; IKK, I kappaB alpha kinase; MDM2, Mouse double minute 2; MEC, Mammary epithelial cell; NAP1, NAK (NF-kappaB-activating kinase)-associated protein 1; NEMO, NF-kappa B essential modulator; PBX1, Pre-B-cell leukemia homeobox protein 1; PCR, Polymerase chain reaction; PI3K, Phosphatidylinositide 3-kinase; TANK, TRAF family member associated NF-kappaB activator; TBK1, TANK-binding kinase 1; TNFα, Tumor necrosis factor alpha

Original Paper

Cell Death and Differentiation advance online publication 31 January 2014; doi: 10.1038/cdd.2014.6

Antitumor effect of miR-197 targeting in p53 wild-type lung cancer

M E Fiori1,2, C Barbini1, T L Haas1,2, N Marroncelli1, M Patrizii1, M Biffoni1 and R De Maria2

1. 1Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy2. 2Regina Elena National Cancer Institute, Rome, Italy

Correspondence: R De Maria, Regina Elena National Cancer Institute, 00144 Rome, Italy. Tel: +39 6 52662726; Fax: +39 6 52665523; E-mail: demaria@ifo.it

Received 31 October 2013; Accepted 18 December 2013Advance online publication 31 January 2014

Edited by M Oren

Top of page

Abstract

Lung cancer is the leading cause of tumor-related death. The lack of effective treatments urges the development of new therapeutic approaches able to selectively kill cancer cells. The connection between aberrant microRNA (miRNA – miR) expression and tumor progression suggests a new strategy to fight cancer by interfering with miRNA function. In this regard, LNAs (locked nucleic acids) have proven to be very promising candidates for miRNA neutralization. Here, we employed an LNA-based anti-miR library in a functional screening to identify putative oncogenic miRNAs in non-small-cell lung cancer (NSCLC). By screening NIH-H460 and A549 cells, miR-197 was identified as a new functional oncomiR, whose downregulation induces p53-dependent lung cancer cell apoptosis and impairs the capacity to establish tumor xenografts in immunodeficient mice. We further identified the two BH3-only proteins NOXA and BMF as new miR-197 targets responsible for induction of apoptosis in p53 wild-type cells, delineating miR-197 as a key survival factor in NSCLC. Thus, we propose the inhibition of miR-197 as a novel therapeutic approach against lung cancer.

Keywords: lung cancer; microRNAs; p53; apoptosis; LNA

Abbreviations: miRNA, miR-, microRNA; SCLC, small cell lung cancer; NSCLC, non small cell lung cancer; LNA, locked nucleic acids; BMF, Bcl-2 modifying factor; PLK, polo like kinase; siRNA, small interfering RNA; UTR, untranslated region; EGF-R, epidermal growth factor receptor; ALK, anaplastic lymphoma kinase; EMT, epithelial-mesenchymal transition

DH

J Invest Dermatol. 2014 Feb 6. doi: 10.1038/jid.2014.34. [Epub ahead of print]

Hippo: Hungry, Hungry for Melanoma Invasion.Sanchez IM, Aplin AE.

Epigenetics. 2014 Feb 5;9(4). [Epub ahead of print]

Overexpression of MYC and EZH2 cooperates to epigenetically silence MST1 expression.Kuser-Abali G1, Alptekin A1, Cinar B2.

Author information

1Department of Medicine-Hematology and Oncology and Biomedical Sciences Cancer Biology; Samuel Oschin Comprehensive Cancer Institute; Cedars-Sinai Medical Center; Los Angeles, CA USA.

2Department of Medicine-Hematology and Oncology and Biomedical Sciences Cancer Biology; Samuel Oschin Comprehensive Cancer Institute; Cedars-Sinai Medical Center; Los Angeles, CA USA; Department of Medicine; David Geffen School of Medicine; University of California Los Angeles; Los Angeles, CA USA.

Abstract

Hippo-like MST1 protein kinase regulates cell growth, organ size, and carcinogenesis. Reduction or loss of MST1 expression is implicated in poor cancer prognosis. However, the mechanism leading to MST1 silencing remains elusive. Here, we report that both MYC and EZH2 function as potent suppressors of MST1 expression in human prostate cancer cells. We demonstrated that concurrent overexpression of MYC and EZH2 was correlated with the reduction or loss of MST1 expression, as shown by RT-qPCR and immunoblotting. Methylation sensitive PCR and bisulfite genomic DNA sequencing showed that DNA methylation caused MST1 silencing. Pharmacologic and RNAi experiments revealed that MYC and EZH2 silenced MST1 expression by inhibiting its promoter activity, and that EZH2 was a mediator of the MYC-induced silencing of MST1 expression. In addition, MYC contributed to MST1 silencing by partly inhibiting the expression of miR-26a/b, a negative regulator of EZH2. As shown by ChIP assays, EZH2-induced DNA methylation and H3K27me3 modification, which was accompanied by a reduced H3K4me3 mark and RNA polymerase II occupancy on the MST1 promoter CpG region, were the underlying cause of MST1 silencing. Moreover, potent pharmacologic inhibitors of MYC or EZH2 suppressed PC cell growth in vitro, and the knockdown of MST1 caused cells' resistance to MYC and EZH2 inhibitor-induced growth retardation. These findings indicate that MYC, in concert with EZH2, epigenetically attenuates MST1 expression and suggest that the loss of MST1/Hippo functions is critical for the MYC or EZH2 mediation of cancer cell survival.

EMBO J. 2014 Feb 4. [Epub ahead of print]

Tumor-propagating cells and Yap/Taz activity contribute to lung tumor progression and metastasis.Lau AN, Curtis SJ, Fillmore CM, Rowbotham SP, Mohseni M, Wagner DE, Beede AM, Montoro DT, Sinkevicius KW, Walton ZE, Barrios J, Weiss DJ, Camargo FD, Wong KK, Kim CF.

Author information

Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.

Abstract

Metastasis is the leading cause of morbidity for lung cancer patients. Here we demonstrate that murine tumor propagating cells (TPCs) with the markers Sca1 and CD24 are enriched for metastatic potential in orthotopic transplantation assays. CD24 knockdown decreased the metastatic potential of lung cancer cell lines resembling TPCs. In lung cancer patient data sets, metastatic spread and patient survival could be stratified with a murine lung TPC gene signature. The TPC signature was enriched for genes in the Hippo signaling pathway. Knockdown of the Hippo mediators Yap1 or Taz decreased in vitro cellular migration and transplantation of metastatic disease. Furthermore, constitutively active Yap was sufficient to drive lung tumor progression in vivo. These results demonstrate functional roles for two different pathways, CD24-dependent and Yap/Taz-dependent pathways, in lung tumor propagation and metastasis. This study demonstrates the utility of TPCs for identifying molecules contributing to metastatic lung cancer, potentially enabling the therapeutic targeting of this devastating disease.

E W

Asian Pac J Cancer Prev. 2013;14(12):7069-74.

Connections Between Various Trigger Factors and the RIP1/ RIP3 Signaling Pathway Involved in Necroptosis.Zhang YY, Liu H.

Author information

Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui, China E-mail : liuhao6886@foxmail.com.

AbstractProgrammed cell death is a basic cellular process that is critical to maintaining tissue homeostasis. In contrast to apoptosis, necrosis was previously regarded as an unregulated and uncontrollable process. However, as research has progressed, necrosis, also known as necroptosis or programmed necrosis, is drawing increasing attention, not least becasu of its possible impications for cancer research. Necroptosis exhibits a unique signaling pathway that requires the involvement of receptor interaction protein kinases 1 and 3 (RIP1 and RIP3), mixed lineage kinase domain-like (MLKL), and phosphoglycerate mutase 5 (PGAM5) and can be specifically inhibited by necrostatins. Not only does necroptosis serve as a backup cell death program when apoptosis is inhibited, but it is now recognized to play a pivotal role in regulating

various physiological processes and the pathogenesis of a variety of human diseases such as ischemic brain injury, immune system disorders and cancer. The control of necroptosis by various defined trigger factors and signaling pathways now offers the opportunity to target this cellular process for therapeutic purposes. The purpose of this paper is to review current findings concerning the connections between various trigger factors and the RIP1/RIP3signaling pathway as it relates to necroptosis.

Blood. 2014 Feb 4. [Epub ahead of print]

cIAPs and XIAP regulate myelopoiesis through cytokine production in a RIPK1 and RIPK3 dependent manner.Wong WW, Vince JE, Lalaoui N, Lawlor KE, Chau D, Bankovacki A, Anderton H, Metcalf D, O'Reilly L, Jost PJ, Murphy JM, Alexander WS, Strasser A, Vaux DL, Silke J.

Author information

The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia;

AbstractLoss of Inhibitor of Apoptosis (IAP) proteins, particularly cIAP1, can promote production of tumor necrosis factor (TNF) and sensitize cancer cell lines to TNF induced necroptosis by promoting formation of a death inducing signaling complex containing receptor-interacting serine/threonine-protein kinase 1 and 3 (RIPK1, RIPK3). To define the role of IAPs in myelopoiesis, we generated a mouse with cIAP1, cIAP2 and XIAP deleted in the myeloid lineage. Loss of cIAPs and XIAP in the myeloid lineage caused over-production of many pro-inflammatory cytokines, resulting in granulocytosis and severe sterile inflammation. In vitro differentiation of macrophages from bone marrow in the absence of cIAPs and XIAP led to detectable levels of TNF and resulted in reduced numbers of mature macrophages. The cytokine production and consequent cell death caused by IAP depletion was attenuated by loss or inhibition of TNF or TNFR1. The loss of RIPK1 or RIPK3, but not the RIPK3 substrate MLKL, attenuated TNF secretion and thereby prevented apoptotic cell death and not necrosis. Our results demonstrate that cIAPs and XIAP together restrain RIPK1 and RIPK3 dependent cytokine production in myeloid cells to critically regulate myeloid homeostasis.

Curr Mol Med. 2014 Jan 27. [Epub ahead of print]

Caspase-8 as a Regulator of Tumor Cell Motility.Graf RP, Keller N, Barbero S, Stupack D.

Author information

University of California San Diego, Moores Cancer Center, Department of Reproductive Medicine, 0803, 3855 Health Sciences Dr., La Jolla, CA 92093, USA. dstupack@ucsd.edu.

AbstractThe caspases are a family of ubiquitously expressed cysteine proteases best known for their roles in programmed cell death. However, caspases play a number of other roles in vertebrates. In the case of caspase-8, loss of expression is an embryonic lethal phenotype, and caspase-8 plays roles in suppressing cellular necrosis, promoting differentiation and immune signaling, regulating autophagy, and promoting cellular migration. Apoptosis and migration require localization of caspase-8 in the periphery of the cells, where caspase-8 acts as part of distinct biosensory complexes that either promote migration in

appropriate cellular microenvironments, or cell death in inappropriate settings. In the cellular periphery,caspase-8 interacts with components of the focal adhesion complex in a tyrosine-kinase dependent manner, promoting both cell migration in vitro and metastasis in vivo. Mechanistically, caspase-8 interacts with components of both focal adhesions and early endosomes, enhancing focal adhesion turnover and promoting rapid integrin recycling to the cell surface. Clinically, this suggests that the expression of   caspase-8   may not always be a positive prognostic sign, and that the role of   caspase-8   in cancer progression is likely context-dependent.

Cell Death Dis. 2014 Jan 30;5:e1043. doi: 10.1038/cddis.2014.5.

Plasminogen activator urokinase expression reveals TRAIL responsiveness and supports fractional survival of cancer cells.Pavet V1, Shlyakhtina Y1, He T2, Ceschin DG1, Kohonen P2, Perälä M2, Kallioniemi O3, Gronemeyer H1.

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AbstractTumor necrosis factor-related apoptosis-inducing ligand (TRAIL/TNFSF10/Apo2L) holds promise for cancer therapy as it induces apoptosis in a large variety of cancer cells while exerting negligible toxicity in normal ones. However, TRAIL can also induce proliferative and migratory signaling in cancer cells resistant to apoptosis induced by this cytokine. In that regard, the molecular mechanisms underlying the tumor selectivity of TRAIL and those balancing apoptosis versus survival remain largely elusive. We show here that high mRNA levels of PLAU, which encodes urokinase plasminogen activator (uPA), are characteristic of cancer cells with functional TRAIL signaling. Notably, decreasing uPA levels sensitized cancer cells to TRAIL, leading to markedly increased apoptosis. Mechanistic analyses revealed three molecular events taking place in uPA-depleted cells: reduced basal ERK1/2 prosurvival signaling, decreased preligand decoy receptor 2 (DcR2)-death receptor 5 (DR5) interaction and attenuated recruitment of DcR2 to the death-inducing signaling complex upon TRAIL challenge. These phenomena were accompanied by increased FADD and procaspase-8 recruitment and processing, thus guiding cells toward a caspase-dependent cell death that is largely independent of the intrinsic apoptosis pathway. Collectively, our results unveil PLAU mRNA levels as marker for the identification of TRAIL-responsive tumor cells and highlight a key role of uPA signaling in 'apoptosis versus survival' decision-making processes upon TRAIL challenge.

Nat Immunol. 2014 Jan 26. doi: 10.1038/ni.2810. [Epub ahead of print]

K63-linked polyubiquitination of transcription factor IRF1 is essential for IL-1-induced production of chemokines CXCL10 and CCL5.Harikumar KB1, Yester JW1, Surace MJ1, Oyeniran C1, Price MM1, Huang WC1, Hait NC1, Allegood JC1, Yamada A2, Kong X3, Lazear HM4, Bhardwaj R1,Takabe K2, Diamond MS4, Luo C3, Milstien S1, Spiegel S1, Kordula T1.

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Abstract

Although interleukin 1 (IL-1) induces expression of the transcription factor IRF1 (interferon-regulatory factor 1), the roles of IRF1 in immune and inflammatory responses and mechanisms of its activation remain elusive. Here we found that IRF1 was essential for IL-1-induced expression of the chemokines CXCL10 and CCL5, which recruit mononuclear cells into sites of sterile inflammation. Newly synthesized IRF1 acquired Lys63 (K63)-linked polyubiquitination mediated by the apoptosis inhibitor   cIAP2  that was enhanced by the bioactive lipid S1P. In response to IL-1, cIAP2 and the sphingosine kinase SphK1 (the enzyme that generates S1P) formed a complex with IRF1, which led to its activation. Thus, IL-1 triggered a hitherto unknown signaling cascade that controlled the induction of IRF1-dependent genes that encode molecules important for sterile inflammation.

MHFEBS J. 2014 Jan 18. doi: 10.1111/febs.12720. [Epub ahead of print]

Involvement of caspase 8 and c-FLIPL in the proangiogenic effects of the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL).

Cantarella G, Di Benedetto G, Ribatti D, Saccani-Jotti G, Bernardini R.

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Department of Clinical and Molecular Biomedicine, University of Catania Medical School, Italy.

Abstract

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), a cytokine of the tumour necrosis factor superfamily, is a potent cell-apoptosis inducer, although its effects vary as a function of concentration. In fact, low concentrations of TRAIL are associated with non-apoptotic effects, such as cell proliferation. Here, the effects of TRAIL at different concentrations have been evaluated on mitogenesis and migration on human umbilical vein endothelial cells (HUVEC) in vitro, as well as in the chick embryo chorioallantoic membrane (CAM) angiogenesis model in vivo. At low concentrations, TRAIL promoted either mitogenesis or migration of HUVEC, evaluated using the wound healing method. Cleavage of caspase 8 was evaluated along with expression of the caspase 8-like molecule, cellular FLICE-inhibitory protein (long form) (c-FLIPL ). Low concentrations of TRAIL failed to induce caspase 8 processing, whereas high concentrations induced apoptosis of HUVEC and activation of caspase 8. Moreover, TRAIL induced a significant angiogenic response in the CAM assay in vivo, comparable with that of vascular endothelial growth factor. These data suggest that the non-apoptotic effects of TRAIL include mitogenesis and increased mobility of endothelial cells, and eventually angiogenesis. In addition, the results demonstrate that the c-FLIPL level is also modulated by differences in TRAIL concentration, suggesting its involvement in the divergent effects of TRAIL. In conclusion, this study envisions a proangiogenic role of TRAIL, suggesting that TRAIL may represent a target for pharmacological manipulation.

Oncogene. 2014 Feb 3. doi: 10.1038/onc.2013.601. [Epub ahead of print]

Delaying mitotic exit downregulates FLIP expression and strongly sensitizes tumor cells to TRAIL.

Sánchez-Pérez T1, Medema RH2, López-Rivas A3.

Author information

11] Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas, Sevilla, Spain [2] Division of cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.

2Division of cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. 3Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo

Superior de Investigaciones Científicas, Sevilla, Spain.

Abstract

Many of the current antitumor therapeutic strategies are based on the perturbation of the cell cycle, especially during mitosis. Antimitotic drugs trigger mitotic checkpoint activation, mitotic arrest and eventually cell death. However, mitotic slippage represents a major mechanism of resistance to these treatments. In an attempt to circumvent the process of slippage, targeting mitotic exit has been proposed as a better strategy to kill tumor cells. In this study, we show that treatments that induce mitotic checkpoint activation and mitotic arrest downregulate FLICE-like inhibitory protein (FLIP) levels and sensitize several tumor cell lines to TRAIL (tumor necrosis factor-related apoptosis-inducing ligand)-induced apoptosis. Interestingly, we also demonstrate that in absence of mitotic checkpoint activation, mitotic arrest induced either by Cdc20 knockdown or overexpression of nondegradable cyclin B is sufficient to induce both FLIP downregulation and sensitivity to TRAIL. In summary, our data suggest that a combination of antimitotic drugs targeting cyclin B degradation and TRAIL might prevent mitotic slippage and allow tumor cells to reach the threshold for apoptosis induction, thereby facilitating tumor suppression.Oncogene advance online publication, 3 February 2014; doi:10.1038/onc.2013.601.