Publications by authors named "Gabriela Kalna"

45 Publications

Selection of established tumour cells through narrow diameter micropores enriches for elevated Ras/Raf/MEK/ERK MAPK signalling and enhanced tumour growth.

Small GTPases 2020 Jun 22:1-17. Epub 2020 Jun 22.

Cancer Research UK Beatson Institute , Glasgow, UK.

As normal cells become cancer cells, and progress towards malignancy, they become progressively softer. Advantages of this change are that tumour cells become more deformable, and better able to move through narrow constraints. We designed a positive selection strategy that enriched for cells which could move through narrow diameter micropores to identify cell phenotypes that enabled constrained migration. Using human MDA MB 231 breast cancer and MDA MB 435 melanoma cancer cells, we found that micropore selection favoured cells with relatively higher Ras/Raf/MEK/ERK mitogen-activated protein kinase (MAPK) signalling, which affected actin cytoskeleton organization, focal adhesion density and cell elasticity. In this follow-up study, we provide further evidence that selection through micropores enriched for cells with altered cell morphology and adhesion. Additional analysis of RNA sequencing data revealed a set of transcripts associated with small cell size that was independent of constrained migration. Gene set enrichment analysis identified the 'matrisome' as the most significantly altered gene set linked with small size. When grown as orthotopic xenograft tumours in immunocompromised mice, micropore selected cells grew significantly faster than Parent or Flow-Sorted cells. Using mathematical modelling, we determined that there is an interaction between 1) the cell to gap size ratio; 2) the bending rigidity of the cell, which enable movement through narrow gaps. These results extend our previous conclusion that Ras/Raf/MEK/ERK MAPK signalling has a significant role in regulating cell biomechanics by showing that the selective pressure of movement through narrow gaps also enriches for increased tumour growth .
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http://dx.doi.org/10.1080/21541248.2020.1780108DOI Listing
June 2020

MCL1 Is Required for Maintenance of Intestinal Homeostasis and Prevention of Carcinogenesis in Mice.

Gastroenterology 2020 07 14;159(1):183-199. Epub 2020 Mar 14.

Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland; Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland. Electronic address:

Background & Aims: Intestinal epithelial homeostasis depends on a tightly regulated balance between intestinal epithelial cell (IEC) death and proliferation. While the disruption of several IEC death regulating factors result in intestinal inflammation, the loss of the anti-apoptotic BCL2 family members BCL2 and BCL2L1 has no effect on intestinal homeostasis in mice. We investigated the functions of the antiapoptotic protein MCL1, another member of the BCL2 family, in intestinal homeostasis in mice.

Methods: We generated mice with IEC-specific disruption of Mcl1 (Mcl1 mice) or tamoxifen-inducible IEC-specific disruption of Mcl1 (i-Mcl1 mice); these mice and mice with full-length Mcl1 (controls) were raised under normal or germ-free conditions. Mice were analyzed by endoscopy and for intestinal epithelial barrier permeability. Intestinal tissues were analyzed by histology, in situ hybridization, proliferation assays, and immunoblots. Levels of calprotectin, a marker of intestinal inflammation, were measured in intestinal tissues and feces.

Results: Mcl1 mice spontaneously developed apoptotic enterocolopathy, characterized by increased IEC apoptosis, hyperproliferative crypts, epithelial barrier dysfunction, and chronic inflammation. Loss of MCL1 retained intestinal crypts in a hyperproliferated state and prevented the differentiation of intestinal stem cells. Proliferation of intestinal stem cells in MCL1-deficient mice required WNT signaling and was associated with DNA damage accumulation. By 1 year of age, Mcl1 mice developed intestinal tumors with morphologic and genetic features of human adenomas and carcinomas. Germ-free housing of Mcl1 mice reduced markers of microbiota-induced intestinal inflammation but not tumor development.

Conclusion: The antiapoptotic protein MCL1, a member of the BCL2 family, is required for maintenance of intestinal homeostasis and prevention of carcinogenesis in mice. Loss of MCL1 results in development of intestinal carcinomas, even under germ-free conditions, and therefore does not involve microbe-induced chronic inflammation. Mcl1 mice might be used to study apoptotic enterocolopathy and inflammatory bowel diseases.
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http://dx.doi.org/10.1053/j.gastro.2020.03.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7397524PMC
July 2020

N-WASP Control of LPAR1 Trafficking Establishes Response to Self-Generated LPA Gradients to Promote Pancreatic Cancer Cell Metastasis.

Dev Cell 2019 11 24;51(4):431-445.e7. Epub 2019 Oct 24.

CRUK Beatson Institute, Glasgow G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1BD, UK. Electronic address:

Pancreatic ductal adenocarcinoma is one of the most invasive and metastatic cancers and has a dismal 5-year survival rate. We show that N-WASP drives pancreatic cancer metastasis, with roles in both chemotaxis and matrix remodeling. lysophosphatidic acid, a signaling lipid abundant in blood and ascites fluid, is both a mitogen and chemoattractant for cancer cells. Pancreatic cancer cells break lysophosphatidic acid down as they respond to it, setting up a self-generated gradient driving tumor egress. N-WASP-depleted cells do not recognize lysophosphatidic acid gradients, leading to altered RhoA activation, decreased contractility and traction forces, and reduced metastasis. We describe a signaling loop whereby N-WASP and the endocytic adapter SNX18 promote lysophosphatidic acid-induced RhoA-mediated contractility and force generation by controlling lysophosphatidic acid receptor recycling and preventing degradation. This chemotactic loop drives collagen remodeling, tumor invasion, and metastasis and could be an important target against pancreatic cancer spread.
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http://dx.doi.org/10.1016/j.devcel.2019.09.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6863394PMC
November 2019

Migration through physical constraints is enabled by MAPK-induced cell softening via actin cytoskeleton re-organization.

J Cell Sci 2019 05 31;132(11). Epub 2019 May 31.

Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK

Cancer cells are softer than the normal cells, and metastatic cells are even softer. These changes in biomechanical properties contribute to cancer progression by facilitating cell movement through physically constraining environments. To identify properties that enabled passage through physical constraints, cells that were more efficient at moving through narrow membrane micropores were selected from established cell lines. By examining micropore-selected human MDA MB 231 breast cancer and MDA MB 435 melanoma cancer cells, membrane fluidity and nuclear elasticity were excluded as primary contributors. Instead, reduced actin cytoskeleton anisotropy, focal adhesion density and cell stiffness were characteristics associated with efficient passage through constraints. By comparing transcriptomic profiles between the parental and selected populations, increased Ras/MAPK signalling was linked with cytoskeleton rearrangements and cell softening. MEK inhibitor treatment reversed the transcriptional, cytoskeleton, focal adhesion and elasticity changes. Conversely, expression of oncogenic KRas in parental MDA MB 231 cells, or oncogenic BRaf in parental MDA MB 435 cells, significantly reduced cell stiffness. These results reveal that MAPK signalling, in addition to tumour cell proliferation, has a significant role in regulating cell biomechanics.This article has an associated First Person interview with the first author of the paper.
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http://dx.doi.org/10.1242/jcs.224071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6589089PMC
May 2019

Improving the metabolic fidelity of cancer models with a physiological cell culture medium.

Sci Adv 2019 01 2;5(1):eaau7314. Epub 2019 Jan 2.

Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G611BD, UK.

Currently available cell culture media may not reproduce the in vivo metabolic environment of tumors. To demonstrate this, we compared the effects of a new physiological medium, Plasmax, with commercial media. We prove that the disproportionate nutrient composition of commercial media imposes metabolic artifacts on cancer cells. Their supraphysiological concentrations of pyruvate stabilize hypoxia-inducible factor 1α in normoxia, thereby inducing a pseudohypoxic transcriptional program. In addition, their arginine concentrations reverse the urea cycle reaction catalyzed by argininosuccinate lyase, an effect not observed in vivo, and prevented by Plasmax in vitro. The capacity of cancer cells to form colonies in commercial media was impaired by lipid peroxidation and ferroptosis and was rescued by selenium present in Plasmax. Last, an untargeted metabolic comparison revealed that breast cancer spheroids grown in Plasmax approximate the metabolic profile of mammary tumors better. In conclusion, a physiological medium improves the metabolic fidelity and biological relevance of in vitro cancer models.
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http://dx.doi.org/10.1126/sciadv.aau7314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6314821PMC
January 2019

Replication Stress Drives Constitutive Activation of the DNA Damage Response and Radioresistance in Glioblastoma Stem-like Cells.

Cancer Res 2018 09 5;78(17):5060-5071. Epub 2018 Jul 5.

Institute of Cancer Sciences, Wolfson Wohl Cancer Research Centre, University of Glasgow, Glasgow, United Kingdom.

Glioblastoma (GBM) is a lethal primary brain tumor characterized by treatment resistance and inevitable tumor recurrence, both of which are driven by a subpopulation of GBM cancer stem-like cells (GSC) with tumorigenic and self-renewal properties. Despite having broad implications for understanding GSC phenotype, the determinants of upregulated DNA-damage response (DDR) and subsequent radiation resistance in GSC are unknown and represent a significant barrier to developing effective GBM treatments. In this study, we show that constitutive DDR activation and radiation resistance are driven by high levels of DNA replication stress (RS). CD133 GSC exhibited reduced DNA replication velocity and a higher frequency of stalled replication forks than CD133 non-GSC ; immunofluorescence studies confirmed these observations in a panel of orthotopic xenografts and human GBM specimens. Exposure of non-GSC to low-level exogenous RS generated radiation resistance , confirming RS as a novel determinant of radiation resistance in tumor cells. GSC exhibited DNA double-strand breaks, which colocalized with "replication factories" and RNA: DNA hybrids. GSC also demonstrated increased expression of long neural genes (>1 Mbp) containing common fragile sites, supporting the hypothesis that replication/transcription collisions are the likely cause of RS in GSC. Targeting RS by combined inhibition of ATR and PARP (CAiPi) provided GSC-specific cytotoxicity and complete abrogation of GSC radiation resistance These data identify RS as a cancer stem cell-specific target with significant clinical potential. These findings shed new light on cancer stem cell biology and reveal novel therapeutics with the potential to improve clinical outcomes by overcoming inherent radioresistance in GBM. .
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http://dx.doi.org/10.1158/0008-5472.CAN-18-0569DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6128404PMC
September 2018

Colorectal Tumors Require NUAK1 for Protection from Oxidative Stress.

Cancer Discov 2018 05 2;8(5):632-647. Epub 2018 Mar 2.

Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.

Exploiting oxidative stress has recently emerged as a plausible strategy for treatment of human cancer, and antioxidant defenses are implicated in resistance to chemotherapy and radiotherapy. Targeted suppression of antioxidant defenses could thus broadly improve therapeutic outcomes. Here, we identify the AMPK-related kinase NUAK1 as a key component of the antioxidant stress response pathway and reveal a specific requirement for this role of NUAK1 in colorectal cancer. We show that NUAK1 is activated by oxidative stress and that this activation is required to facilitate nuclear import of the antioxidant master regulator NRF2: Activation of NUAK1 coordinates PP1β inhibition with AKT activation in order to suppress GSK3β-dependent inhibition of NRF2 nuclear import. Deletion of NUAK1 suppresses formation of colorectal tumors, whereas acute depletion of NUAK1 induces regression of preexisting autochthonous tumors. Importantly, elevated expression of NUAK1 in human colorectal cancer is associated with more aggressive disease and reduced overall survival. This work identifies NUAK1 as a key facilitator of the adaptive antioxidant response that is associated with aggressive disease and worse outcome in human colorectal cancer. Our data suggest that transient NUAK1 inhibition may provide a safe and effective means for treatment of human colorectal cancer via disruption of intrinsic antioxidant defenses. .
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http://dx.doi.org/10.1158/2159-8290.CD-17-0533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935231PMC
May 2018

MCL-1 is a prognostic indicator and drug target in breast cancer.

Cell Death Dis 2018 01 16;9(2):19. Epub 2018 Jan 16.

CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK.

Analysis of publicly available genomic and gene expression data demonstrates that MCL1 expression is frequently elevated in breast cancer. Distinct from other pro-survival Bcl-2 family members, the short half-life of MCL-1 protein led us to investigate MCL-1 protein expression in a breast cancer tissue microarray and correlate this with clinical data. Here, we report associations between high MCL-1 and poor prognosis in specific subtypes of breast cancer including triple-negative breast cancer, an aggressive form that lacks targeted treatment options. Deletion of MCL-1 in the mammary epithelium of genetically engineered mice revealed an absolute requirement for MCL-1 in breast tumorigenesis. The clinical applicability of these findings was tested through a combination of approaches including knock-down or inhibition of MCL-1 to show triple-negative breast cancer cell line dependence on MCL-1 in vitro and in vivo. Our data demonstrate that high MCL-1 protein expression is associated with poor outcome in breast cancer and support the therapeutic targeting of MCL-1 in this disease.
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http://dx.doi.org/10.1038/s41419-017-0035-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833338PMC
January 2018

Transcriptomic profiling of human breast and melanoma cells selected by migration through narrow constraints.

Sci Data 2017 11 14;4:170172. Epub 2017 Nov 14.

Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK.

The metastatic spread of cancer cells is a step-wise process that starts with dissociation from primary tumours and local invasion of adjacent tissues. The ability to invade local tissues is the product of several processes, including degradation of extracellular matrices (ECM) and movement of tumour cells through physically-restricting gaps. To identify properties contributing to tumour cells squeezing through narrow gaps, invasive MDA-MB-231 human breast cancer and MDA-MB-435 human melanoma cells were subjected to three successive rounds of selection using cell culture inserts with highly constraining 3 μm pores. For comparison purposes, flow cytometry was also employed to enrich for small diameter MDA-MB-231 cells. RNA-Sequencing (RNA-seq) using the Illumina NextSeq 500 platform was undertaken to characterize how gene expression differed between parental, invasive pore selected or small diameter cells. Gene expression results obtained by RNA-seq were validated by comparing with RT-qPCR. Transcriptomic data generated could be used to determine how alterations that enable cell passage through narrow spaces contribute to local invasion and metastasis.
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http://dx.doi.org/10.1038/sdata.2017.172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5685158PMC
November 2017

Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.

PLoS Genet 2017 Jul 14;13(7):e1006870. Epub 2017 Jul 14.

Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH, United States of America.

Wnt/β-catenin signal transduction directs intestinal stem cell (ISC) proliferation during homeostasis. Hyperactivation of Wnt signaling initiates colorectal cancer, which most frequently results from truncation of the tumor suppressor Adenomatous polyposis coli (APC). The β-catenin-TCF transcription complex activates both the physiological expression of Wnt target genes in the normal intestinal epithelium and their aberrantly increased expression in colorectal tumors. Whether mechanistic differences in the Wnt transcription machinery drive these distinct levels of target gene activation in physiological versus pathological states remains uncertain, but is relevant for the design of new therapeutic strategies. Here, using a Drosophila model, we demonstrate that two evolutionarily conserved transcription cofactors, Earthbound (Ebd) and Erect wing (Ewg), are essential for all major consequences of Apc1 inactivation in the intestine: the hyperactivation of Wnt target gene expression, excess number of ISCs, and hyperplasia of the epithelium. In contrast, only Ebd, but not Ewg, mediates the Wnt-dependent regulation of ISC proliferation during homeostasis. Therefore, in the adult intestine, Ebd acts independently of Ewg in physiological Wnt signaling, but cooperates with Ewg to induce the hyperactivation of Wnt target gene expression following Apc1 loss. These findings have relevance for human tumorigenesis, as Jerky (JRK/JH8), the human Ebd homolog, promotes Wnt pathway hyperactivation and is overexpressed in colorectal, breast, and ovarian cancers. Together, our findings reveal distinct requirements for Ebd and Ewg in physiological Wnt pathway activation versus oncogenic Wnt pathway hyperactivation following Apc1 loss. Such differentially utilized transcription cofactors may offer new opportunities for the selective targeting of Wnt-driven cancers.
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http://dx.doi.org/10.1371/journal.pgen.1006870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5510812PMC
July 2017

ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth.

EMBO Mol Med 2017 02;9(2):198-218

Cancer Research UK Beatson Institute, Glasgow, UK

Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer death; identifying PDAC enablers may reveal potential therapeutic targets. Expression of the actomyosin regulatory ROCK1 and ROCK2 kinases increased with tumor progression in human and mouse pancreatic tumors, while elevated ROCK1/ROCK2 expression in human patients, or conditional ROCK2 activation in a Kras/p53 mouse PDAC model, was associated with reduced survival. Conditional ROCK1 or ROCK2 activation promoted invasive growth of mouse PDAC cells into three-dimensional collagen matrices by increasing matrix remodeling activities. RNA sequencing revealed a coordinated program of ROCK-induced genes that facilitate extracellular matrix remodeling, with greatest fold-changes for matrix metalloproteinases (MMPs) Mmp10 and Mmp13 MMP inhibition not only decreased collagen degradation and invasion, but also reduced proliferation in three-dimensional contexts. Treatment of Kras/p53 PDAC mice with a ROCK inhibitor prolonged survival, which was associated with increased tumor-associated collagen. These findings reveal an ancillary role for increased ROCK signaling in pancreatic cancer progression to promote extracellular matrix remodeling that facilitates proliferation and invasive tumor growth.
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http://dx.doi.org/10.15252/emmm.201606743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5286371PMC
February 2017

ROCK signalling induced gene expression changes in mouse pancreatic ductal adenocarcinoma cells.

Sci Data 2016 11 8;3:160101. Epub 2016 Nov 8.

Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK.

The RhoA and RhoC GTPases act via the ROCK1 and ROCK2 kinases to promote actomyosin contraction, resulting in directly induced changes in cytoskeleton structures and altered gene transcription via several possible indirect routes. Elevated activation of the Rho/ROCK pathway has been reported in several diseases and pathological conditions, including disorders of the central nervous system, cardiovascular dysfunctions and cancer. To determine how increased ROCK signalling affected gene expression in pancreatic ductal adenocarcinoma (PDAC) cells, we transduced mouse PDAC cell lines with retroviral constructs encoding fusion proteins that enable conditional activation of ROCK1 or ROCK2, and subsequently performed RNA sequencing (RNA-Seq) using the Illumina NextSeq 500 platform. We describe how gene expression datasets were generated and validated by comparing data obtained by RNA-Seq with RT-qPCR results. Activation of ROCK1 or ROCK2 signalling induced significant changes in gene expression that could be used to determine how actomyosin contractility influences gene transcription in pancreatic cancer.
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http://dx.doi.org/10.1038/sdata.2016.101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5100681PMC
November 2016

Microarray screening of Guillain-Barré syndrome sera for antibodies to glycolipid complexes.

Neurol Neuroimmunol Neuroinflamm 2016 Dec 28;3(6):e284. Epub 2016 Sep 28.

Institute of Infection, Immunity and Inflammation (S.K.H., H.J.W.), College of Medical, Veterinary and Life Sciences, University of Glasgow; The Beatson Institute for Cancer Research (G.K.), Glasgow, UK; Laboratory Sciences and Services Division (M.B.I., I.J., Q.D.M., Z.I.), International Centre for Diarrheal Disease Research; Shaheed Tajuddin Ahmed Sarani (M.B.I., I.J., Q.D.M., Z.I.), Mohakhali, Dhaka, Bangladesh; Departments of Immunology and Neurology (B.C.J.) and Medical Microbiology and Infectious Diseases (H.P.E.), Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and Fondation Mérieux (H.P.E.), Lyon, France.

Objective: To characterize the patterns of autoantibodies to glycolipid complexes in a large cohort of Guillain-Barré syndrome (GBS) and control samples collected in Bangladesh using a newly developed microarray technique.

Methods: Twelve commonly studied glycolipids and lipids, plus their 66 possible heteromeric complexes, totaling 78 antigens, were applied to polyvinylidene fluoride-coated slides using a microarray printer. Arrays were probed with 266 GBS and 579 control sera (2 μL per serum, diluted 1/50) and bound immunoglobulin G detected with secondary antibody. Scanned arrays were subjected to statistical analyses.

Results: Measuring antibodies to single targets was 9% less sensitive than to heteromeric complex targets (49.2% vs 58.3%) without significantly affecting specificity (83.9%-85.0%). The optimal screening protocol for GBS sera comprised a panel of 10 glycolipids (4 single glycolipids GM1, GA1, GD1a, GQ1b, and their 6 heteromeric complexes), resulting in an overall assay sensitivity of 64.3% and specificity of 77.1%. Notable heteromeric targets were GM1:GD1a, GM1:GQ1b, and GA1:GD1a, in which exclusive binding to the complex was observed.

Conclusions: Rationalizing the screening protocol to capture the enormous diversity of glycolipid complexes can be achieved by miniaturizing the screening platform to a microarray platform, and applying simple bioinformatics to determine optimal sensitivity and specificity of the targets. Glycolipid complexes are an important category of glycolipid antigens in autoimmune neuropathy cases that require specific analytical and bioinformatics methods for optimal detection.
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http://dx.doi.org/10.1212/NXI.0000000000000284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5055300PMC
December 2016

The initiator methionine tRNA drives cell migration and invasion leading to increased metastatic potential in melanoma.

Biol Open 2016 Oct 15;5(10):1371-1379. Epub 2016 Oct 15.

Beatson Institute for Cancer Research, Garscube Estate, Glasgow G61 1BD, Scotland

The cell's repertoire of transfer RNAs (tRNAs) has been linked to cancer. Recently, the level of the initiator methionine tRNA (tRNA) in stromal fibroblasts has been shown to influence extracellular matrix (ECM) secretion to drive tumour growth and angiogenesis. Here we show that increased tRNA within cancer cells does not influence tumour growth, but drives cell migration and invasion via a mechanism that is independent from ECM synthesis and dependent on α5β1 integrin and levels of the translation initiation ternary complex. In vivo and ex vivo migration (but not proliferation) of melanoblasts is significantly enhanced in transgenic mice which express additional copies of the tRNA gene. We show that increased tRNA in melanoma drives migratory, invasive behaviour and metastatic potential without affecting cell proliferation and primary tumour growth, and that expression of RNA polymerase III-associated genes (which drive tRNA expression) are elevated in metastases by comparison with primary tumours. Thus, specific alterations to the cancer cell tRNA repertoire drive a migration/invasion programme that may lead to metastasis.
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http://dx.doi.org/10.1242/bio.019075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5087684PMC
October 2016

The PI3K regulatory subunit gene PIK3R1 is under direct control of androgens and repressed in prostate cancer cells.

Oncoscience 2015 14;2(9):755-64. Epub 2015 Sep 14.

Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.

Androgen receptor (AR) signalling and the PI3K pathway mediate survival signals in prostate cancer, and have been shown to regulate each other by reciprocal negative feedback, such that inhibition of one activates the other. Understanding the reciprocal regulation of these pathways is important for disease management as tumour cells can adapt and survive when either single pathway is inhibited pharmacologically. We recently carried out genome-wide exon-specific profiling of prostate cancer cells to identify novel androgen-regulated transcriptional events. Here we interrogated this dataset for novel androgen-regulated genes associated with the PI3K pathway. We find that the PI3K regulatory subunits PIK3R1 (p85α) and PIK3R3 (p55γ) are direct targets of the AR which are rapidly repressed by androgens in LNCaP cells. Further characterisation revealed that the PIK3CA p110α catalytic subunit is also indirectly regulated by androgens at the protein level. We show that PIK3R1 mRNA is significantly under-expressed in prostate cancer (PCa) tissue, and provide data to suggest a context-dependent regulatory mechanism whereby repression of the p85α protein by the AR results in destabilisation of the PI3K p110α catalytic subunit and downstream PI3K pathway inhibition that functionally affects the properties of prostate cancer cells.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4606009PMC
http://dx.doi.org/10.18632/oncoscience.243DOI Listing
October 2015

Pyruvate carboxylation enables growth of SDH-deficient cells by supporting aspartate biosynthesis.

Nat Cell Biol 2015 Oct 24;17(10):1317-26. Epub 2015 Aug 24.

Cancer Research UK, Beatson Institute, Switchback Rd, Glasgow G61 1BD, UK.

Succinate dehydrogenase (SDH) is a heterotetrameric nuclear-encoded complex responsible for the oxidation of succinate to fumarate in the tricarboxylic acid cycle. Loss-of-function mutations in any of the SDH genes are associated with cancer formation. However, the impact of SDH loss on cell metabolism and the mechanisms enabling growth of SDH-defective cells are largely unknown. Here, we generated Sdhb-ablated kidney mouse cells and used comparative metabolomics and stable-isotope-labelling approaches to identify nutritional requirements and metabolic adaptations to SDH loss. We found that lack of SDH activity commits cells to consume extracellular pyruvate, which sustains Warburg-like bioenergetic features. We further demonstrated that pyruvate carboxylation diverts glucose-derived carbons into aspartate biosynthesis, thus sustaining cell growth. By identifying pyruvate carboxylase as essential for the proliferation and tumorigenic capacity of SDH-deficient cells, this study revealed a metabolic vulnerability for potential future treatment of SDH-associated malignancies.
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http://dx.doi.org/10.1038/ncb3233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591470PMC
October 2015

E-cadherin can limit the transforming properties of activating β-catenin mutations.

EMBO J 2015 Sep 3;34(18):2321-33. Epub 2015 Aug 3.

Cancer Research UK Beatson Institute, Glasgow, UK

Wnt pathway deregulation is a common characteristic of many cancers. Only colorectal cancer predominantly harbours mutations in APC, whereas other cancer types (hepatocellular carcinoma, solid pseudopapillary tumours of the pancreas) have activating mutations in β-catenin (CTNNB1). We have compared the dynamics and the potency of β-catenin mutations in vivo. Within the murine small intestine (SI), an activating mutation of β-catenin took much longer to achieve Wnt deregulation and acquire a crypt-progenitor cell (CPC) phenotype than Apc or Gsk3 loss. Within the colon, a single activating mutation of β-catenin was unable to drive Wnt deregulation or induce the CPC phenotype. This ability of β-catenin mutation to differentially transform the SI versus the colon correlated with higher expression of E-cadherin and a higher number of E-cadherin:β-catenin complexes at the membrane. Reduction in E-cadherin synergised with an activating mutation of β-catenin resulting in a rapid CPC phenotype within the SI and colon. Thus, there is a threshold of β-catenin that is required to drive transformation, and E-cadherin can act as a buffer to sequester mutated β-catenin.
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http://dx.doi.org/10.15252/embj.201591739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4570519PMC
September 2015

A study of the effects of exercise on the urinary metabolome using normalisation to individual metabolic output.

Metabolites 2015 Feb 27;5(1):119-39. Epub 2015 Feb 27.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK.

Aerobic exercise, in spite of its multi-organ benefit and potent effect on the metabolome, has yet to be investigated comprehensively via an untargeted metabolomics technology. We conducted an exploratory untargeted liquid chromatography mass spectrometry study to investigate the effects of a one-h aerobic exercise session in the urine of three physically active males. Individual urine samples were collected over a 37-h protocol (two pre-exercise and eight post-exercise). Raw data were subjected to a variety of normalization techniques, with the most effective measure dividing each metabolite by the sum response of that metabolite for each individual across the 37-h protocol expressed as a percentage. This allowed the metabolite responses to be plotted on a normalised scale. Our results highlight significant metabolites located in the following systems: purine pathway, tryptophan metabolism, carnitine metabolism, cortisol metabolism, androgen metabolism, amino acid oxidation, as well as metabolites from the gastrointestinal microbiome. Many of the significant changes observed in our pilot investigation mirror previous research studies, of various methodological designs, published within the last 15 years, although they have never been reported at the same time in a single study.
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http://dx.doi.org/10.3390/metabo5010119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4381293PMC
February 2015

Fumarate induces redox-dependent senescence by modifying glutathione metabolism.

Nat Commun 2015 Jan 23;6:6001. Epub 2015 Jan 23.

Cancer Research UK, Beatson Institute, Switchback Road, Glasgow G61 1BD, UK.

Mutations in the tricarboxylic acid (TCA) cycle enzyme fumarate hydratase (FH) are associated with a highly malignant form of renal cancer. We combined analytical chemistry and metabolic computational modelling to investigate the metabolic implications of FH loss in immortalized and primary mouse kidney cells. Here, we show that the accumulation of fumarate caused by the inactivation of FH leads to oxidative stress that is mediated by the formation of succinicGSH, a covalent adduct between fumarate and glutathione. Chronic succination of GSH, caused by the loss of FH, or by exogenous fumarate, leads to persistent oxidative stress and cellular senescence in vitro and in vivo. Importantly, the ablation of p21, a key mediator of senescence, in Fh1-deficient mice resulted in the transformation of benign renal cysts into a hyperplastic lesion, suggesting that fumarate-induced senescence needs to be bypassed for the initiation of renal cancers.
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http://dx.doi.org/10.1038/ncomms7001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4340546PMC
January 2015

Androgen-regulation of the protein tyrosine phosphatase PTPRR activates ERK1/2 signalling in prostate cancer cells.

BMC Cancer 2015 Jan 16;15. Epub 2015 Jan 16.

Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK.

Background: Androgens drive the onset and progression of prostate cancer (PCa) via androgen receptor (AR) signalling. The principal treatment for PCa is androgen deprivation therapy, although the majority of patients eventually develop a lethal castrate-resistant form of the disease, where despite low serum testosterone levels AR signalling persists. Advanced PCa often has hyper-activated RAS/ERK1/2 signalling thought to be due to loss of function of key negative regulators of the pathway, the details of which are not fully understood.

Methods: We recently carried out a genome-wide study and identified a subset of 226 novel androgen-regulated genes (PLOS ONE 6:e29088, 2011). In this study we have meta-analysed this dataset with genes and pathways frequently mutated in PCa to identify androgen-responsive regulators of the RAS/ERK1/2 pathway.

Results: We find the PTGER4 and TSPYL2 genes are up-regulated by androgen stimulation and the ADCY1, OPKR1, TRIB1, SPRY1 and PTPRR are down-regulated by androgens. Further characterisation of PTPRR protein in LNCaP cells revealed it is an early and direct target of the androgen receptor which negatively regulates the RAS/ERK1/2 pathway and reduces cell proliferation in response to androgens.

Conclusion: Our data suggest that loss of PTPRR in clinical PCa is one factor that might contribute to activation of the RAS/ERK1/2 pathway.
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http://dx.doi.org/10.1186/s12885-015-1012-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4302442PMC
January 2015

Acetyl-CoA synthetase 2 promotes acetate utilization and maintains cancer cell growth under metabolic stress.

Cancer Cell 2015 Jan;27(1):57-71

Cancer Research UK, Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK. Electronic address:

A functional genomics study revealed that the activity of acetyl-CoA synthetase 2 (ACSS2) contributes to cancer cell growth under low-oxygen and lipid-depleted conditions. Comparative metabolomics and lipidomics demonstrated that acetate is used as a nutritional source by cancer cells in an ACSS2-dependent manner, and supplied a significant fraction of the carbon within the fatty acid and phospholipid pools. ACSS2 expression is upregulated under metabolically stressed conditions and ACSS2 silencing reduced the growth of tumor xenografts. ACSS2 exhibits copy-number gain in human breast tumors, and ACSS2 expression correlates with disease progression. These results signify a critical role for acetate consumption in the production of lipid biomass within the harsh tumor microenvironment.
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http://dx.doi.org/10.1016/j.ccell.2014.12.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4297291PMC
January 2015

Identification of a candidate prognostic gene signature by transcriptome analysis of matched pre- and post-treatment prostatic biopsies from patients with advanced prostate cancer.

BMC Cancer 2014 Dec 18;14:977. Epub 2014 Dec 18.

Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.

Background: Although chemotherapy for prostate cancer (PCa) can improve patient survival, some tumours are chemo-resistant. Tumour molecular profiles may help identify the mechanisms of drug action and identify potential prognostic biomarkers. We performed in vivo transcriptome profiling of pre- and post-treatment prostatic biopsies from patients with advanced hormone-naive prostate cancer treated with docetaxel chemotherapy and androgen deprivation therapy (ADT) with an aim to identify the mechanisms of drug action and identify prognostic biomarkers.

Methods: RNA sequencing (RNA-Seq) was performed on biopsies from four patients before and ~22 weeks after docetaxel and ADT initiation. Gene fusion products and differentially-regulated genes between treatment pairs were identified using TopHat and pathway enrichment analyses undertaken. Publically available datasets were interrogated to perform survival analyses on the gene signatures identified using cBioportal.

Results: A number of genomic rearrangements were identified including the TMPRSS2/ERG fusion and 3 novel gene fusions involving the ETS family of transcription factors in patients, both pre and post chemotherapy. In total, gene expression analyses showed differential expression of at least 2 fold in 575 genes in post-chemotherapy biopsies. Of these, pathway analyses identified a panel of 7 genes (ADAM7, FAM72B, BUB1B, CCNB1, CCNB2, TTK, CDK1), including a cell cycle-related geneset, that were differentially-regulated following treatment with docetaxel and ADT. Using cBioportal to interrogate the MSKCC-Prostate Oncogenome Project dataset we observed a statistically-significant reduction in disease-free survival of patients with tumours exhibiting alterations in gene expression of the above panel of 7 genes (p = 0.015).

Conclusions: Here we report on the first "real-time" in vivo RNA-Seq-based transcriptome analysis of clinical PCa from pre- and post-treatment TRUSS-guided biopsies of patients treated with docetaxel chemotherapy plus ADT. We identify a chemotherapy-driven PCa transcriptome profile which includes the down-regulation of important positive regulators of cell cycle progression. A 7 gene signature biomarker panel has also been identified in high-risk prostate cancer patients to be of prognostic value. Future prospective study is warranted to evaluate the clinical value of this panel.
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http://dx.doi.org/10.1186/1471-2407-14-977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301544PMC
December 2014

Impaired neutrophil directional chemotactic accuracy in chronic periodontitis patients.

J Clin Periodontol 2015 Jan 8;42(1):1-11. Epub 2015 Jan 8.

Periodontal Research Group and MRC Centre for Immune Regulation, University of Birmingham, Birmingham, UK.

Aim: To investigate the chemotactic accuracy of peripheral blood neutrophils from patients with chronic periodontitis compared with matched healthy controls, before and after non-surgical periodontal therapy.

Material & Methods: Neutrophils were isolated from patients and controls (n = 18) by density centrifugation. Using the Insall chamber and video microscopy, neutrophils were analysed for directional chemotaxis towards N-formyl-methionyl-leucyl-phenylalanine [fMLP (10 nM), or CXCL8 (200 ng/ml)]. Circular statistics were utilized for the analysis of cell movement.

Results: Prior to treatment, neutrophils from patients with chronic periodontitis had significantly reduced speed, velocity and chemotactic accuracy compared to healthy controls for both chemoattractants. Following periodontal treatment, patient neutrophils continued to display reduced speed in response to both chemoattractants. However, velocity and accuracy were normalized for the weak chemoattractant CXCL8 while they remained significantly reduced for fMLP.

Conclusions: Chronic periodontitis is associated with reduced neutrophil chemotaxis, and this is only partially restored by successful treatment. Dysfunctional neutrophil chemotaxis may predispose patients with periodontitis to their disease by increasing tissue transit times, thus exacerbating neutrophil-mediated collateral host tissue damage.
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http://dx.doi.org/10.1111/jcpe.12326DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4340045PMC
January 2015

Melanoma cells break down LPA to establish local gradients that drive chemotactic dispersal.

PLoS Biol 2014 Oct 14;12(10):e1001966. Epub 2014 Oct 14.

CRUK Beatson Institute, Glasgow, United Kingdom.

The high mortality of melanoma is caused by rapid spread of cancer cells, which occurs unusually early in tumour evolution. Unlike most solid tumours, thickness rather than cytological markers or differentiation is the best guide to metastatic potential. Multiple stimuli that drive melanoma cell migration have been described, but it is not clear which are responsible for invasion, nor if chemotactic gradients exist in real tumours. In a chamber-based assay for melanoma dispersal, we find that cells migrate efficiently away from one another, even in initially homogeneous medium. This dispersal is driven by positive chemotaxis rather than chemorepulsion or contact inhibition. The principal chemoattractant, unexpectedly active across all tumour stages, is the lipid agonist lysophosphatidic acid (LPA) acting through the LPA receptor LPAR1. LPA induces chemotaxis of remarkable accuracy, and is both necessary and sufficient for chemotaxis and invasion in 2-D and 3-D assays. Growth factors, often described as tumour attractants, cause negligible chemotaxis themselves, but potentiate chemotaxis to LPA. Cells rapidly break down LPA present at substantial levels in culture medium and normal skin to generate outward-facing gradients. We measure LPA gradients across the margins of melanomas in vivo, confirming the physiological importance of our results. We conclude that LPA chemotaxis provides a strong drive for melanoma cells to invade outwards. Cells create their own gradients by acting as a sink, breaking down locally present LPA, and thus forming a gradient that is low in the tumour and high in the surrounding areas. The key step is not acquisition of sensitivity to the chemoattractant, but rather the tumour growing to break down enough LPA to form a gradient. Thus the stimulus that drives cell dispersal is not the presence of LPA itself, but the self-generated, outward-directed gradient.
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http://dx.doi.org/10.1371/journal.pbio.1001966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4196730PMC
October 2014

CLIC3 controls recycling of late endosomal MT1-MMP and dictates invasion and metastasis in breast cancer.

J Cell Sci 2014 Sep 11;127(Pt 18):3893-901. Epub 2014 Jul 11.

Beatson Institute for Cancer Research: Garscube Estate, Glasgow G61 1BD, UK

Chloride intracellular channel 3 (CLIC3) drives invasiveness of pancreatic and ovarian cancer by acting in concert with Rab25 to regulate the recycling of α5β1 integrin from late endosomes to the plasma membrane. Here, we show that in two estrogen receptor (ER)-negative breast cancer cell lines, CLIC3 has little influence on integrin recycling, but controls trafficking of the pro-invasive matrix metalloproteinase MT1-MMP (also known as MMP14). In MDA-MB-231 cells, MT1-MMP and CLIC3 are localized primarily to late endosomal/lysosomal compartments located above the plane of adhesion and near the nucleus. MT1-MMP is transferred from these late endosomes to sites of cell-matrix adhesion in a CLIC3-dependent fashion. Correspondingly, CLIC3-knockdown opposes MT1-MMP-dependent invasive processes. These include the disruption of the basement membrane as acini formed from MCF10DCIS.com cells acquire invasive characteristics in 3D culture, and the invasion of MDA-MB-231 cells into Matrigel or organotypic plugs of type I collagen. Consistent with this, expression of CLIC3 predicts poor prognosis in ER-negative breast cancer. The identification of MT1-MMP as a cargo of a CLIC3-regulated pathway that drives invasion highlights the importance of late endosomal sorting and trafficking in breast cancer.
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http://dx.doi.org/10.1242/jcs.135947DOI Listing
September 2014

Targeting mTOR dependency in pancreatic cancer.

Gut 2014 Sep 9;63(9):1481-9. Epub 2014 Apr 9.

CRUK Beatson Institute, Glasgow, UK.

Objective: Pancreatic cancer is a leading cause of cancer-related death in the Western world. Current chemotherapy regimens have modest survival benefit. Thus, novel, effective therapies are required for treatment of this disease.

Design: Activating KRAS mutation almost always drives pancreatic tumour initiation, however, deregulation of other potentially druggable pathways promotes tumour progression. PTEN loss leads to acceleration of Kras(G12D)-driven pancreatic ductal adenocarcinoma (PDAC) in mice and these tumours have high levels of mammalian target of rapamycin (mTOR) signalling. To test whether these KRAS PTEN pancreatic tumours show mTOR dependence, we compared response to mTOR inhibition in this model, to the response in another established model of pancreatic cancer, KRAS P53. We also assessed whether there was a subset of pancreatic cancer patients who may respond to mTOR inhibition.

Results: We found that tumours in KRAS PTEN mice exhibit a remarkable dependence on mTOR signalling. In these tumours, mTOR inhibition leads to proliferative arrest and even tumour regression. Further, we could measure response using clinically applicable positron emission tomography imaging. Importantly, pancreatic tumours driven by activated KRAS and mutant p53 did not respond to treatment. In human tumours, approximately 20% of cases demonstrated low PTEN expression and a gene expression signature that overlaps with murine KRAS PTEN tumours.

Conclusions: KRAS PTEN tumours are uniquely responsive to mTOR inhibition. Targeted anti-mTOR therapies may offer clinical benefit in subsets of human PDAC selected based on genotype, that are dependent on mTOR signalling. Thus, the genetic signatures of human tumours could be used to direct pancreatic cancer treatment in the future.
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http://dx.doi.org/10.1136/gutjnl-2013-306202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145424PMC
September 2014

Antibodies to heteromeric glycolipid complexes in Guillain-Barré syndrome.

PLoS One 2013 16;8(12):e82337. Epub 2013 Dec 16.

Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.

Autoantibodies are infrequently detected in the sera of patients with the demyelinating form of Guillain-Barré syndrome most commonly encountered in the Western world, despite abundant circumstantial evidence suggesting their existence. We hypothesised that antibody specificities reliant on the cis interactions of neighbouring membrane glycolipids could explain this discrepancy, and would not have been detected by traditional serological assays using highly purified preparations of single gangliosides. To assess the frequency of glycolipid complex antibodies in a Western European cohort of patients GBS we used a newly developed combinatorial glycoarray methodology to screen against large range of antigens (11 gangliosides, 8 other single glycolipids and 162 heterodimeric glycolipid complexes). Serum samples of 181 patients from a geographically defined, Western European cohort of GBS cases were analysed, along with 161 control sera. Serum IgG binding to single gangliosides was observed in 80.0% of axonal GBS cases, but in only 11.8% of cases with demyelinating electrophysiology. The inclusion of glycolipid complexes increased the positivity rate in demyelinating disease to 62.4%. There were 40 antigens with statistically significantly increased binding intensities in GBS as compared to healthy control sera. Of these, 7 complex antigens and 1 single ganglioside also produced statistically significantly increased binding intensities in GBS versus neurological disease controls. The detection of antibodies against specific complexes was associated with particular clinical features including disease severity, requirement for mechanical ventilation, and axonal electrophysiology. This study demonstrates that while antibodies against single gangliosides are often found in cases with axonal-type electrophysiology, antibodies against glycolipid complexes predominate in cases with demyelinating electrophysiology, providing a more robust serum biomarker than has ever been previously available for such cases. This work confirms the activation of the humoral immune system in the dysimmune disease process in GBS, and correlates patterns of antigen recognition with different clinical features.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0082337PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864991PMC
September 2014

Reversed argininosuccinate lyase activity in fumarate hydratase-deficient cancer cells.

Cancer Metab 2013 Mar 21;1(1):12. Epub 2013 Mar 21.

Cancer Research UK, Beatson Institute for Cancer Research, Switchback Road, Glasgow, G61 1BD, UK.

Background: Loss of function of fumarate hydratase (FH), the mitochondrial tumor suppressor and tricarboxylic acid (TCA) cycle enzyme, is associated with a highly malignant form of papillary and collecting duct renal cell cancer. The accumulation of fumarate in these cells has been linked to the tumorigenic process. However, little is known about the overall effects of the loss of FH on cellular metabolism.

Methods: We performed comprehensive metabolomic analyses of urine from Fh1-deficient mice and stable isotopologue tracing from human and mouse FH-deficient cell lines to investigate the biochemical signature of the loss of FH.

Results: The metabolomics analysis revealed that the urea cycle metabolite argininosuccinate is a common metabolic biomarker of FH deficiency. Argininosuccinate was found to be produced from arginine and fumarate by the reverse activity of the urea cycle enzyme argininosuccinate lyase (ASL), making these cells auxotrophic for arginine. Depleting arginine from the growth media by the addition of pegylated arginine deiminase (ADI-PEG 20) decreased the production of argininosuccinate in FH-deficient cells and reduced cell survival and proliferation.

Conclusions: These results unravel a previously unidentified correlation between fumarate accumulation and the urea cycle enzyme ASL in FH-deficient cells. The finding that FH-deficient cells become auxotrophic for arginine opens a new therapeutic perspective for the cure of hereditary leiomyomatosis and renal cell cancer (HLRCC).
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http://dx.doi.org/10.1186/2049-3002-1-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108060PMC
March 2013

Abi is required for modulation and stability but not localization or activation of the SCAR/WAVE complex.

Eukaryot Cell 2013 Nov 13;12(11):1509-16. Epub 2013 Sep 13.

Beatson Institute for Cancer Research, Bearsden, Glasgow, United Kingdom.

The SCAR/WAVE complex drives actin-based protrusion, cell migration, and cell separation during cytokinesis. However, the contribution of the individual complex members to the activity of the whole remains a mystery. This is primarily because complex members depend on one another for stability, which limits the scope for experimental manipulation. Several studies suggest that Abi, a relatively small complex member, connects signaling to SCAR/WAVE complex localization and activation through its polyproline C-terminal tail. We generated a deletion series of the Dictyostelium discoideum Abi to investigate its exact role in regulation of the SCAR complex and identified a minimal fragment that would stabilize the complex. Surprisingly, loss of either the N terminus of Abi or the C-terminal polyproline tail conferred no detectable defect in complex recruitment to the leading edge or the formation of pseudopods. A fragment containing approximately 20% Abi--and none of the sites that couple to known signaling pathways--allowed the SCAR complex to function with normal localization and kinetics. However, expression of N-terminal Abi deletions exacerbated the cytokinesis defect of the Dictyostelium abi mutant, which was earlier shown to be caused by the inappropriate activation of SCAR. This demonstrates, unexpectedly, that Abi does not mediate the SCAR complex's ability to make pseudopods, beyond its role in complex stability. Instead, we propose that Abi has a modulatory role when the SCAR complex is activated through other mechanisms.
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http://dx.doi.org/10.1128/EC.00116-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3837927PMC
November 2013

Prostate gland lengths and iceball dimensions predict micturition functional outcome following salvage prostate cryotherapy in men with radiation recurrent prostate cancer.

PLoS One 2013 9;8(8):e69243. Epub 2013 Aug 9.

Urology Group, Beatson Institute for Cancer Research, Bearsden, Glasgow, United Kingdom.

Introduction: Tissue cryoablation is a potential curative option for solid malignancies, including radiation recurrent prostate cancer (RRPC). Case series of salvage cryotherapy (SCT) in RRPC have reported promising disease free survival (DFS) outcomes and acceptable toxicity profile. While many men receive SCT, no predictive factors for treatment induced side effects are known. The aim of this study is to validate the oncologic outcome of SCT in a large multi-centre patient cohort and to identify potential parameters associated with an increased risk of micturition symptoms.

Patients And Methods: In this retrospective analysis, we studied 283 consecutive patients with RRPC treated by SCT in three independent U.K. centres (between 2001 and 2011). Two freeze-thaw cycles of transperineal cryotherapy were performed under transrectal ultrasound guidance by a single surgeon in each of the 3 sites. We analysed clinico-pathological factors against tumour response. Functional outcomes were assessed by continence status and IPSS questionnaire. Predictive factors for SCT-induced micturition symptoms were analysed in a sub-group (n=42) of consecutive cases.

Results: We found that nadir post-SCT PSA levels strongly associated with DFS. The DFS rates at 12- and 36-month were 84% and 67% for the ≤ 1 ng/ml group and 56% and 14% for the >1 ng/ml group, respectively (p<0.001). Correlative analysis revealed highly significant association between patients' post-SCT micturition status with prostate gland and iceball lengths following SCT. Finally, in a reduction model, both gland length and maximal length of iceball were highly associated with patients' IPSS outcome (p<0.001).

Conclusion: We report the largest European patient cohort treated with SCT for RRPC. Oncologic outcome guided by nadir PSA of <1 ng/ml is consistent with earlier single-centre series. For the first time, we identified physical parameters to predict micturition symptoms following SCT. Our data will directly assist on-going and future trial design in cryotherapy in prostate cancer.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0069243PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3739755PMC
March 2014