Publications by authors named "Chiara Bardella"

22 Publications

  • Page 1 of 1

Advances in Research of Adult Gliomas.

Int J Mol Sci 2021 Jan 18;22(2). Epub 2021 Jan 18.

Institute of Cancer Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.

Diffuse gliomas are the most frequent brain tumours, representing 75% of all primary malignant brain tumours in adults. Because of their locally aggressive behaviour and the fact that they cannot be cured by current therapies, they represent one of the most devastating cancers. The present review summarises recent advances in our understanding of glioma development and progression by use of various in vitro and in vivo models, as well as more complex techniques including cultures of 3D organoids and organotypic slices. We discuss the progress that has been made in understanding glioma heterogeneity, alteration in gene expression and DNA methylation, as well as advances in various in silico models. Lastly current treatment options and future clinical trials, which aim to improve early diagnosis and disease monitoring, are also discussed.
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http://dx.doi.org/10.3390/ijms22020924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7831916PMC
January 2021

Anion-exchange chromatography mass spectrometry provides extensive coverage of primary metabolic pathways revealing altered metabolism in IDH1 mutant cells.

Commun Biol 2020 05 20;3(1):247. Epub 2020 May 20.

Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.

Altered central carbon metabolism is a hallmark of many diseases including diabetes, obesity, heart disease and cancer. Identifying metabolic changes will open opportunities for better understanding aetiological processes and identifying new diagnostic, prognostic, and therapeutic targets. Comprehensive and robust analysis of primary metabolic pathways in cells, tissues and bio-fluids, remains technically challenging. We report on the development and validation of a highly reproducible and robust untargeted method using anion-exchange tandem mass spectrometry (IC-MS) that enables analysis of 431 metabolites, providing detailed coverage of central carbon metabolism. We apply the method in an untargeted, discovery-driven workflow to investigate the metabolic effects of isocitrate dehydrogenase 1 (IDH1) mutations in glioblastoma cells. IC-MS provides comprehensive coverage of central metabolic pathways revealing significant elevation of 2-hydroxyglutarate and depletion of 2-oxoglutarate. Further analysis of the data reveals depletion in additional metabolites including previously unrecognised changes in lysine and tryptophan metabolism.
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http://dx.doi.org/10.1038/s42003-020-0957-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7239943PMC
May 2020

Serum- and Glucocorticoid-induced Kinase Sgk1 Directly Promotes the Differentiation of Colorectal Cancer Cells and Restrains Metastasis.

Clin Cancer Res 2019 01 15;25(2):629-640. Epub 2018 Oct 15.

Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom.

Purpose: The molecular events that determine intestinal cell differentiation are poorly understood and it is unclear whether it is primarily a passive event or an active process. It is clinically important to gain a greater understanding of the process, because in colorectal cancer, the degree of differentiation of a tumor is associated with patient survival. has previously been identified as a gene that is principally expressed in differentiated intestinal cells. In colorectal cancer, there is marked downregulation of compared with normal tissue. An inducible viral overexpression system was utilized to induce reexpression of in colorectal cancer cell lines. Transcriptomic and phenotypic analyses of these colorectal cancer lines was performed and validation in mouse and human cohorts was performed.

Results: We demonstrate that is upregulated in response to, and an important controller of, intestinal cell differentiation. Reexpression of in colorectal cancer cell lines results in features of differentiation, decreased migration rates, and inhibition of metastasis in an orthotopic xenograft model. These effects may be mediated, in part, by SGK1-induced PKP3 expression and increased degradation of MYC.

Conclusions: Our results suggest that is an important mediator of differentiation of colorectal cells and may inhibit colorectal cancer metastasis.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-1033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6339518PMC
January 2019

The role of inflammation in subventricular zone cancer.

Prog Neurobiol 2018 11 11;170:37-52. Epub 2018 Apr 11.

Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK. Electronic address:

The adult subventricular zone (SVZ) stem cell niche has proven vital for discovering neurodevelopmental mechanisms and holds great potential in medicine for neurodegenerative diseases. Yet the SVZ holds a dark side - it can become tumorigenic. Glioblastomas can arise from the SVZ via cancer stem cells (CSCs). Glioblastoma and other brain cancers often have dismal prognoses since they are resistant to treatment. In this review we argue that the SVZ is susceptible to cancer because it contains stem cells, migratory progenitors and unusual inflammation. Theoretically, SVZ stem cells can convert to CSCs more readily than can postmitotic neural cells. Additionally, the robust long-distance migration of SVZ progenitors can be subverted upon tumorigenesis to an infiltrative phenotype. There is evidence that the SVZ, even in health, exhibits chronic low-grade cellular and molecular inflammation. Its inflammatory response to brain injuries and disease differs from that of other brain regions. We hypothesize that the SVZ inflammatory environment can predispose cells to novel mutations and exacerbate cancer phenotypes. This can be studied in animal models in which human mutations related to cancer are knocked into the SVZ to induce tumorigenesis and the CSC immune interactions that precede full-blown cancer. Importantly inflammation can be pharmacologically modulated providing an avenue to brain cancer management and treatment. The SVZ is accessible by virtue of its location surrounding the lateral ventricles and CSCs in the SVZ can be targeted with a variety of pharmacotherapies. Thus, the SVZ can yield aggressive tumors but can be targeted via several strategies.
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http://dx.doi.org/10.1016/j.pneurobio.2018.04.007DOI Listing
November 2018

Oncogenic IDH1 Mutations Promote Enhanced Proline Synthesis through PYCR1 to Support the Maintenance of Mitochondrial Redox Homeostasis.

Cell Rep 2018 03;22(12):3107-3114

Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. Electronic address:

Since the discovery of mutations in isocitrate dehydrogenase 1 (IDH1) in gliomas and other tumors, significant efforts have been made to gain a deeper understanding of the consequences of this oncogenic mutation. One aspect of the neomorphic function of the IDH1 R132H enzyme that has received less attention is the perturbation of cellular redox homeostasis. Here, we describe a biosynthetic pathway exhibited by cells expressing mutant IDH1. By virtue of a change in cellular redox homeostasis, IDH1-mutated cells synthesize excess glutamine-derived proline through enhanced activity of pyrroline 5-carboxylate reductase 1 (PYCR1), coupled to NADH oxidation. Enhanced proline biosynthesis partially uncouples the electron transport chain from tricarboxylic acid (TCA) cycle activity through the maintenance of a lower NADH/NAD ratio and subsequent reduction in oxygen consumption. Thus, we have uncovered a mechanism by which tumor cell survival may be promoted in conditions associated with perturbed redox homeostasis, as occurs in IDH1-mutated glioma.
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http://dx.doi.org/10.1016/j.celrep.2018.02.084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5883319PMC
March 2018

Bone morphogenetic protein and Notch signalling crosstalk in poor-prognosis, mesenchymal-subtype colorectal cancer.

J Pathol 2017 06 3;242(2):178-192. Epub 2017 May 3.

Gastrointestinal Stem-cell Biology Laboratory, Oxford Centre for Cancer Gene Research, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.

The functional role of bone morphogenetic protein (BMP) signalling in colorectal cancer (CRC) is poorly defined, with contradictory results in cancer cell line models reflecting the inherent difficulties of assessing a signalling pathway that is context-dependent and subject to genetic constraints. By assessing the transcriptional response of a diploid human colonic epithelial cell line to BMP ligand stimulation, we generated a prognostic BMP signalling signature, which was applied to multiple CRC datasets to investigate BMP heterogeneity across CRC molecular subtypes. We linked BMP and Notch signalling pathway activity and function in human colonic epithelial cells, and normal and neoplastic tissue. BMP induced Notch through a γ-secretase-independent interaction, regulated by the SMAD proteins. In homeostasis, BMP/Notch co-localization was restricted to cells at the top of the intestinal crypt, with more widespread interaction in some human CRC samples. BMP signalling was downregulated in the majority of CRCs, but was conserved specifically in mesenchymal-subtype tumours, where it interacts with Notch to induce an epithelial-mesenchymal transition (EMT) phenotype. In intestinal homeostasis, BMP-Notch pathway crosstalk is restricted to differentiating cells through stringent pathway segregation. Conserved BMP activity and loss of signalling stringency in mesenchymal-subtype tumours promotes a synergistic BMP-Notch interaction, and this correlates with poor patient prognosis. BMP signalling heterogeneity across CRC subtypes and cell lines can account for previous experimental contradictions. Crosstalk between the BMP and Notch pathways will render mesenchymal-subtype CRC insensitive to γ-secretase inhibition unless BMP activation is concomitantly addressed. © 2017 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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http://dx.doi.org/10.1002/path.4891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5488238PMC
June 2017

Expression of Idh1 in the Murine Subventricular Zone Stem Cell Niche Recapitulates Features of Early Gliomagenesis.

Cancer Cell 2016 10 29;30(4):578-594. Epub 2016 Sep 29.

Molecular & Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK. Electronic address:

Isocitrate dehydrogenase 1 mutations drive human gliomagenesis, probably through neomorphic enzyme activity that produces D-2-hydroxyglutarate. To model this disease, we conditionally expressed Idh1 in the subventricular zone (SVZ) of the adult mouse brain. The mice developed hydrocephalus and grossly dilated lateral ventricles, with accumulation of 2-hydroxyglutarate and reduced α-ketoglutarate. Stem and transit amplifying/progenitor cell populations were expanded, and proliferation increased. Cells expressing SVZ markers infiltrated surrounding brain regions. SVZ cells also gave rise to proliferative subventricular nodules. DNA methylation was globally increased, while hydroxymethylation was decreased. Mutant SVZ cells overexpressed Wnt, cell-cycle and stem cell genes, and shared an expression signature with human gliomas. Idh1 mutation in the major adult neurogenic stem cell niche causes a phenotype resembling gliomagenesis.
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http://dx.doi.org/10.1016/j.ccell.2016.08.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064912PMC
October 2016

Recurrent chromosomal gains and heterogeneous driver mutations characterise papillary renal cancer evolution.

Nat Commun 2015 Mar 19;6:6336. Epub 2015 Mar 19.

Genomic analysis of tumour development, Instituto de Biomedicina y Biotecnología de Cantabria (CSIC-UC-Sodercan), Departamento de Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.

Papillary renal cell carcinoma (pRCC) is an important subtype of kidney cancer with a problematic pathological classification and highly variable clinical behaviour. Here we sequence the genomes or exomes of 31 pRCCs, and in four tumours, multi-region sequencing is undertaken. We identify BAP1, SETD2, ARID2 and Nrf2 pathway genes (KEAP1, NHE2L2 and CUL3) as probable drivers, together with at least eight other possible drivers. However, only ~10% of tumours harbour detectable pathogenic changes in any one driver gene, and where present, the mutations are often predicted to be present within cancer sub-clones. We specifically detect parallel evolution of multiple SETD2 mutations within different sub-regions of the same tumour. By contrast, large copy number gains of chromosomes 7, 12, 16 and 17 are usually early, monoclonal changes in pRCC evolution. The predominance of large copy number variants as the major drivers for pRCC highlights an unusual mode of tumorigenesis that may challenge precision medicine approaches.
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http://dx.doi.org/10.1038/ncomms7336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4383019PMC
March 2015

mutation screening in human glioblastomas.

Future Sci OA 2015;1(3)

Molecular & Population Genetics Laboratory, Wellcome Trust Center for Human Genetics, University of Oxford, Oxford, UK.

Aims: Somatic mutations in and are described in glioblastomas (GBMs). Mutant IDH1 and IDH2 reduce α-KG to D-2HG which accumulates, and is proposed to promote tumorigenesis. HOT catalyzes the conversion of γ-hydroxybutyrate to succinic semialdehyde in a reaction that produces D-2HG. Since increased HOT enzyme activity could lead to an accumulation of D-2HG, coupled with the fact that only a minority of GBMs carry mutations and 2HG accumulation has recently been described in wild-type tumors, we analyzed a set of GBM samples for mutations in the gene.

Materials & Methods: We screened 42 human GBM samples for mutations in .

Results: No mutations in were identified in the 42 GBM samples screened.

Conclusion: Mutations in the coding regions of do not occur at an appreciable frequency in GBM.
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http://dx.doi.org/10.4155/fso.15.20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776344PMC
January 2015

Aberrant epithelial GREM1 expression initiates colonic tumorigenesis from cells outside the stem cell niche.

Nat Med 2015 Jan 1;21(1):62-70. Epub 2014 Dec 1.

Gastrointestinal Stem cell Biology Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.

Hereditary mixed polyposis syndrome (HMPS) is characterized by the development of mixed-morphology colorectal tumors and is caused by a 40-kb genetic duplication that results in aberrant epithelial expression of the gene encoding mesenchymal bone morphogenetic protein antagonist, GREM1. Here we use HMPS tissue and a mouse model of the disease to show that epithelial GREM1 disrupts homeostatic intestinal morphogen gradients, altering cell fate that is normally determined by position along the vertical epithelial axis. This promotes the persistence and/or reacquisition of stem cell properties in Lgr5-negative progenitor cells that have exited the stem cell niche. These cells form ectopic crypts, proliferate, accumulate somatic mutations and can initiate intestinal neoplasia, indicating that the crypt base stem cell is not the sole cell of origin of colorectal cancer. Furthermore, we show that epithelial expression of GREM1 also occurs in traditional serrated adenomas, sporadic premalignant lesions with a hitherto unknown pathogenesis, and these lesions can be considered the sporadic equivalents of HMPS polyps.
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http://dx.doi.org/10.1038/nm.3750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594755PMC
January 2015

IDH mutations in tumorigenesis and their potential role as novel therapeutic targets.

Future Oncol 2013 Dec;9(12):1923-35

Molecular & Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.

Isocitrate dehydrogenases (IDHs) catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG). Somatic mutations in genes encoding IDH1 and IDH2 were first identified in glioma and subsequently in acute myeloid leukemia and other solid tumors. These heterozygous point mutations occur at the arginine residue of the enzyme's active site and cause both loss of normal enzyme function and gain of function, causing reduction of α-KG to D-2-hydroxyglutarate, which accumulates. D-2-hydroxyglutarate may act as an oncometabolite through the inhibition of various α-KG-dependent enzymes, stimulating angiogenesis, histone modifications and aberrant DNA methylation. Possibly, IDH mutations may also cause oncogenic effects through dysregulation of the tricarboxylic acid cycle, or by increasing susceptibility to oxidative stress. Clinically, IDH mutations may be useful diagnostic, prognostic and predictive biomarkers, and it is anticipated that a better understanding of the pathogenesis of IDH mutations will enable IDH-directed therapies to be developed in the future.
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http://dx.doi.org/10.2217/fon.13.143DOI Listing
December 2013

Cells lacking the fumarase tumor suppressor are protected from apoptosis through a hypoxia-inducible factor-independent, AMPK-dependent mechanism.

Mol Cell Biol 2012 Aug 29;32(15):3081-94. Epub 2012 May 29.

Department of Oncological Sciences, University of Torino, School of Medicine, Turin, Italy.

Loss-of-function mutations of the tumor suppressor gene encoding fumarase (FH) occur in individuals with hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC). We found that loss of FH activity conferred protection from apoptosis in normal human renal cells and fibroblasts. In FH-defective cells, both hypoxia-inducible factor 1α (HIF-1α) and HIF-2α accumulated, but they were not required for apoptosis protection. Conversely, AMP-activated protein kinase (AMPK) was activated and required, as evidenced by the finding that FH inactivation failed to protect AMPK-null mouse embryo fibroblasts (MEFs) and AMPK-depleted human renal cells. Activated AMPK was detected in renal cysts, which occur in mice with kidney-targeted deletion of Fh1 and in kidney cancers of HLRCC patients. In Fh1-null MEFs, AMPK activation was sustained by fumarate accumulation and not by defective energy metabolism. Addition of fumarate and succinate to kidney cells led to extracellular signal-regulated kinase 1/2 (ERK1/2) and AMPK activation, probably through a receptor-mediated mechanism. These findings reveal a new mechanism of tumorigenesis due to FH loss and an unexpected pro-oncogenic role for AMPK that is important in considering AMPK reactivation as a therapeutic strategy against cancer.
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http://dx.doi.org/10.1128/MCB.06160-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3434507PMC
August 2012

Common genetic variants at the 11q13.3 renal cancer susceptibility locus influence binding of HIF to an enhancer of cyclin D1 expression.

Nat Genet 2012 Mar 11;44(4):420-5, S1-2. Epub 2012 Mar 11.

Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, UK.

Although genome-wide association studies (GWAS) have identified the existence of numerous population-based cancer susceptibility loci, mechanistic insights remain limited, particularly for intergenic polymorphisms. Here, we show that polymorphism at a remote intergenic region on chromosome 11q13.3, recently identified as a susceptibility locus for renal cell carcinoma, modulates the binding and function of hypoxia-inducible factor (HIF) at a previously unrecognized transcriptional enhancer of CCND1 (encoding cyclin D1) that is specific for renal cancers characterized by inactivation of the von Hippel-Lindau tumor suppressor (pVHL). The protective haplotype impairs binding of HIF-2, resulting in an allelic imbalance in cyclin D1 expression, thus affecting a link between hypoxia pathways and cell cycle control.
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http://dx.doi.org/10.1038/ng.2204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3378637PMC
March 2012

SDH mutations in cancer.

Biochim Biophys Acta 2011 Nov 13;1807(11):1432-43. Epub 2011 Jul 13.

Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.

The SDHA, SDHB, SDHC, SDHD genes encode the four subunits of succinate dehydrogenase (SDH; mitochondrial complex II), a mitochondrial enzyme involved in two essential energy-producing metabolic processes of the cell, the Krebs cycle and the electron transport chain. Germline loss-of-function mutations in any of the SDH genes or assembly factor (SDHAF2) cause hereditary paraganglioma/phaeochromocytoma syndrome (HPGL/PCC) through a mechanism which is largely unknown. Owing to the central function of SDH in cellular energy metabolism it is important to understand its role in tumor suppression. Here is reported an overview of genetics, clinical and molecular progress recently performed in understanding the basis of HPGL/PCC tumorigenesis.
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http://dx.doi.org/10.1016/j.bbabio.2011.07.003DOI Listing
November 2011

Aberrant succination of proteins in fumarate hydratase-deficient mice and HLRCC patients is a robust biomarker of mutation status.

J Pathol 2011 Sep 1;225(1):4-11. Epub 2011 Jun 1.

Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, Oxford, UK.

Germline mutations in the FH gene encoding the Krebs cycle enzyme fumarate hydratase predispose to hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. FH-deficient cells and tissues accumulate high levels of fumarate, which may act as an oncometabolite and contribute to tumourigenesis. A recently proposed role for fumarate in the covalent modification of cysteine residues to S-(2-succinyl) cysteine (2SC) (termed protein succination) prompted us to assess 2SC levels in our existing models of HLRCC. Herein, using a previously characterized antibody against 2SC, we show that genetic ablation of FH causes high levels of protein succination. We next hypothesized that immunohistochemistry for 2SC would serve as a metabolic biomarker for the in situ detection of FH-deficient tissues. Robust detection of 2SC was observed in Fh1 (murine FH)-deficient renal cysts and in a retrospective series of HLRCC tumours (n = 16) with established FH mutations. Importantly, 2SC was undetectable in normal tissues (n = 200) and tumour types not associated with HLRCC (n = 1342). In a prospective evaluation of cases referred for genetic testing for HLRCC, the presence of 2SC-modified proteins (2SCP) correctly predicted genetic alterations in FH in every case. In two series of unselected type II papillary renal cancer (PRCC), prospectively analysed by 2SCP staining followed by genetic analysis, the biomarker accurately identified previously unsuspected FH mutations (2/33 and 1/36). The investigation of whether metabolites in other tumour types produce protein modification signature(s) that can be assayed using similar strategies will be of interest in future studies of cancer.
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http://dx.doi.org/10.1002/path.2932DOI Listing
September 2011

Screen for IDH1, IDH2, IDH3, D2HGDH and L2HGDH mutations in glioblastoma.

PLoS One 2011 23;6(5):e19868. Epub 2011 May 23.

Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.

Isocitrate dehydrogenases (IDHs) catalyse oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG). IDH1 functions in the cytosol and peroxisomes, whereas IDH2 and IDH3 are both localized in the mitochondria. Heterozygous somatic mutations in IDH1 occur at codon 132 in 70% of grade II-III gliomas and secondary glioblastomas (GBMs), and in 5% of primary GBMs. Mutations in IDH2 at codon 172 are present in grade II-III gliomas at a low frequency. IDH1 and IDH2 mutations cause both loss of normal enzyme function and gain-of-function, causing reduction of α-KG to D-2-hydroxyglutarate (D-2HG) which accumulates. Excess hydroxyglutarate (2HG) can also be caused by germline mutations in D- and L-2-hydroxyglutarate dehydrogenases (D2HGDH and L2HGDH). If loss of IDH function is critical for tumourigenesis, we might expect some tumours to acquire somatic IDH3 mutations. Alternatively, if 2HG accumulation is critical, some tumours might acquire somatic D2HGDH or L2HGDH mutations. We therefore screened 47 glioblastoma samples looking for changes in these genes. Although IDH1 R132H was identified in 12% of samples, no mutations were identified in any of the other genes. This suggests that mutations in IDH3, D2HGDH and L2HGDH do not occur at an appreciable frequency in GBM. One explanation is simply that mono-allelic IDH1 and IDH2 mutations occur more frequently by chance than the bi-allelic mutations expected at IDH3, D2HGDH and L2HGDH. Alternatively, both loss of IDH function and 2HG accumulation might be required for tumourigenesis, and only IDH1 and IDH2 mutations have these dual effects.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019868PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100313PMC
November 2011

Expression profiling in progressive stages of fumarate-hydratase deficiency: the contribution of metabolic changes to tumorigenesis.

Cancer Res 2010 Nov 26;70(22):9153-65. Epub 2010 Oct 26.

Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Headington, United Kingdom.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is caused by mutations in the Krebs cycle enzyme fumarate hydratase (FH). It has been proposed that "pseudohypoxic" stabilization of hypoxia-inducible factor-α (HIF-α) by fumarate accumulation contributes to tumorigenesis in HLRCC. We hypothesized that an additional direct consequence of FH deficiency is the establishment of a biosynthetic milieu. To investigate this hypothesis, we isolated primary mouse embryonic fibroblast (MEF) lines from Fh1-deficient mice. As predicted, these MEFs upregulated Hif-1α and HIF target genes directly as a result of FH deficiency. In addition, detailed metabolic assessment of these MEFs confirmed their dependence on glycolysis, and an elevated rate of lactate efflux, associated with the upregulation of glycolytic enzymes known to be associated with tumorigenesis. Correspondingly, Fh1-deficient benign murine renal cysts and an advanced human HLRCC-related renal cell carcinoma manifested a prominent and progressive increase in the expression of HIF-α target genes and in genes known to be relevant to tumorigenesis and metastasis. In accord with our hypothesis, in a variety of different FH-deficient tissues, including a novel murine model of Fh1-deficient smooth muscle, we show a striking and progressive upregulation of a tumorigenic metabolic profile, as manifested by increased PKM2 and LDHA protein. Based on the models assessed herein, we infer that that FH deficiency compels cells to adopt an early, reversible, and progressive protumorigenic metabolic milieu that is reminiscent of that driving the Warburg effect. Targets identified in these novel and diverse FH-deficient models represent excellent potential candidates for further mechanistic investigation and therapeutic metabolic manipulation in tumors.
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http://dx.doi.org/10.1158/0008-5472.CAN-10-1949DOI Listing
November 2010

Fumarase tumor suppressor gene and MET oncogene cooperate in upholding transformation and tumorigenesis.

FASEB J 2010 Aug 30;24(8):2680-8. Epub 2010 Mar 30.

Department of Oncological Sciences, University of Torino School of Medicine, Turin, Italy.

Loss of the fumarate hydratase (FH) tumor suppressor gene results in the development of benign tumors that rarely, but regrettably, progress to very aggressive cancers. Using mouse embryo fibroblasts (MEFs) to model transformation, we found that fh knockdown results in increased expression of the met oncogene-encoded tyrosine kinase receptor through hypoxia-inducible factor (hif) stabilization. MET-increased expression was alone able to stabilize hif, thus establishing a feed forward loop that might enforce tumor progression. The fh-defective MEFs showed increased motility and protection from apoptosis. Motility, but not survival, relied on hif-1alpha and was greatly enhanced by MET ligand hepatocyte growth factor. Met cooperated with a weakly oncogenic ras in making MEFs transformed and tumorigenic, as shown by in vitro and in vivo assays. Loss of fh was not equally effective by itself but enhanced the transformed and tumorigenic phenotype induced by ras and MET. Consistently, the rescue of fumarase expression abrogated the motogenic and transformed phenotype of fh-defective MEFs. In conclusion, the data suggest that the progression of tumors where FH is lost might be boosted by activation of the MET oncogene, which is able to drive cell-autonomous tumor progression and is a strong candidate for targeted therapy.
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http://dx.doi.org/10.1096/fj.09-146928DOI Listing
August 2010

ERalpha as ligand-independent activator of CDH-1 regulates determination and maintenance of epithelial morphology in breast cancer cells.

Proc Natl Acad Sci U S A 2009 May 21;106(18):7420-5. Epub 2009 Apr 21.

Department of Medicine, Howard Hughes Medical Institute, University of California at San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0651, USA.

Estrogen receptor alpha (ERalpha) and E-cadherin are primary markers of luminal epithelial breast cancer cells with E-cadherin being a main caretaker of the epithelial phenotype. E-cadherin repression is needed for cancer cells to acquire motile and invasive properties, and it is known that in ER-positive breast cancer cells, estrogen down-regulate E-cadherin gene transcription. We report here that ERalpha is bound to the E-cadherin promoter in both the presence and the complete absence of estrogen, suggesting an unexpected role for unliganded ERalpha in E-cadherin transcription. Indeed, our data reveal that activation by unliganded ERalpha and repression by estrogen-activated ERalpha require direct binding to a half-estrogen response element within the E-cadherin promoter and exchange from associated coactivators to corepressors. Therefore, these results suggest a pivotal role for unliganded ERalpha in controlling a fundamental caretaker of the epithelial phenotype in breast cancer cells. Here, we show that ERalpha-positive breast cancer T47D cells transduced with the sfRON kinase undergo a full epithelial-mesenchymal conversion and lose E-cadherin and ERalpha expression. Our data show that, although the E-cadherin gene becomes hypermethylated and heterochromatic, kinase inhibitors can restore E-cadherin expression, together with an epithelial morphology in an ERalpha-dependent fashion. Similarly, transfection of ERalpha, in the absence of ligands, was sufficient to restore E-cadherin transcription in both sfRON-T47D and other ERalpha-, E-cadherin-negative cells. Therefore, our results suggest a novel role for the ERalpha that plays the dual role of ligand-independent activator and ligand-dependent repressor of E-cadherin in breast cancer cells.
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http://dx.doi.org/10.1073/pnas.0903033106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671327PMC
May 2009

The therapeutic potential of hepatocyte growth factor to sensitize ovarian cancer cells to cisplatin and paclitaxel in vivo.

Clin Cancer Res 2007 Apr;13(7):2191-8

Laboratory of Cancer Genetics and Division of Molecular Oncology of the Institute for Cancer Research and Treatment, University of Torino School of Medicine, Candiolo, Turin, Italy.

Purpose: Advanced ovarian cancers are initially responsive to combinatorial chemotherapy with platinum drugs and taxanes but, in most cases, develop drug resistance. We recently showed that, in vitro, hepatocyte growth factor (HGF) enhances death of human ovarian cancer cell lines treated with cisplatin (CDDP) and paclitaxel. The present study addresses whether in vivo HGF makes ovarian carcinoma cells more responsive to these chemotherapeutics.

Experimental Design: Using Lentiviral vectors carrying the HGF transgene, we transduced SK-OV-3 and NIH:OVCAR-3 ovarian carcinoma cell lines to obtain stable autocrine and paracrine HGF receptor activation. In vitro, we assayed growth, motility, invasiveness, and the response to CDDP and paclitaxel of the HGF-secreting bulk unselected cell populations. In vivo, we tested the cytotoxic effects of the drugs versus s.c. tumors formed by the wild-type and HGF-secreting cells in immunocompromised mice. Tumor-bearing mice were treated with CDDP (i.p.) and paclitaxel (i.v.), combined in different schedules and doses.

Results: In vitro, HGF-secreting cells did not show altered proliferation rates and survival but were strongly sensitized to the death triggered by CDDP and paclitaxel, alone or in combination. In vivo, we found a therapeutic window in which autocrine/paracrine HGF made tumors sensitive to low doses of the drugs, which were ineffective on their own.

Conclusions: These data provide the proof-of-concept that in vivo gene therapy with HGF might be competent in sensitizing ovarian cancer cells to conventional chemotherapy.
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http://dx.doi.org/10.1158/1078-0432.CCR-06-1915DOI Listing
April 2007

p38 MAPK turns hepatocyte growth factor to a death signal that commits ovarian cancer cells to chemotherapy-induced apoptosis.

Int J Cancer 2006 Jun;118(12):2981-90

Laboratory of Cancer Genetics, Institute for Cancer Research and Treatment, University of Turin Medical School, Candiolo, Italy.

We recently showed that Hepatocyte Growth Factor (HGF), known as a survival factor, unexpectedly enhances apoptosis in human ovarian cancer cells treated with the front-line chemotherapeutics cisplatin (CDDP) and paclitaxel (PTX). Here we demonstrate that this effect depends on the p38 mitogen-activated kinase (MAPK). In fact, p38 MAPK activity is stimulated by HGF and further increased by the combined treatment with HGF and either CDDP or PTX. The expression of a dominant negative form of p38 MAPK abrogates apoptosis elicited by drugs, alone or in combination with HGF. HGF and drugs also activate the ERK1/2 MAPKs, the PI3K/AKT and the AKT substrate mTOR. However, activation of these survival pathways does not hinder the ability of HGF to enhance drug-dependent apoptosis. Altogether data show that p38 MAPK is necessary for HGF sensitization of ovarian cancer cells to low-doses of CDDP and PTX and might be sufficient to overcome activation of survival pathways. Therefore, the p38 MAPK pathway might be a suitable target to improve response to conventional chemotherapy in human ovarian cancer.
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http://dx.doi.org/10.1002/ijc.21766DOI Listing
June 2006

Truncated RON tyrosine kinase drives tumor cell progression and abrogates cell-cell adhesion through E-cadherin transcriptional repression.

Cancer Res 2004 Aug;64(15):5154-61

Laboratory of Cancer Genetics, Institute for Cancer Research and Treatment, University of Torino Medical School, 10060 Candiolo, Turin, Italy.

RON is a tyrosine kinase receptor that triggers scattering of normal cells and invasive growth of cancer cells on ligand binding. We identified a short RON mRNA, which is expressed in human lung, ovary, tissues of the gastrointestinal tract, and also in several human cancers, including ovarian carcinomas and cell lines from pancreatic carcinomas and leukemias. This transcript encodes a truncated protein (short-form RON; sf-RON), lacking most of the RON receptor extracellular domain but retaining the whole transmembrane and intracellular domains. Sf-RON shows strong intrinsic tyrosine kinase activity and is constitutively phosphorylated. Epithelial cells transduced with sf-RON display an aggressive phenotype; they shift to a nonepithelial morphology, are unable to form aggregates, grow faster in monolayer cultures, show anchorage-independent growth, and become motile. We show that in these cells, E-cadherin expression is lost through a dominant transcriptional repression pathway likely mediated by the transcriptional factor SLUG. Altogether, these data show that expression of a naturally occurring, constitutively active truncated RON kinase results in loss of epithelial phenotype and aggressive behavior and, thus, it might contribute to tumor progression.
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http://dx.doi.org/10.1158/0008-5472.CAN-04-0600DOI Listing
August 2004
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