Abstracts
Michael J. Thun, S. Jane Henley and Ted Gansler
American Cancer Society, 1599 Clifton Road, Atlanta, GA, 30329-4251, USA
Many chronic inflammatory conditions increase the risk of cancer in affected tissues. Clinical conditions that
involve both inflammation and increased cancer risk include a broad range of immunological disorders, infections
(bacterial, helminthic, viral), and chronic chemical and mechanical irritation. For example, the inflammatory
bowel diseases, ulcerative colitis and Crohn’s disease, predispose to the development of cancers of the large
bowel and/or terminal ileum; chronic infection with the bacterium Helicobacter pylori
causes atrophic gastritis,
dysplasia, adenocarcinoma and an unusual form of gastric lymphoma; and parasitic infection with schistosomes and
other trematodes cause cancers of the urinary bladder and the intrahepatic and extrahepatic biliary tract.
Chronic reflux of gastric acid and bile into the distal oesophagus causes chemical injury, Barrett’s oesophagus
and oesophageal adenocarcinoma. Chronic cholescystitis and gallstones predispose to cancer of the gallbladder.
Besides these clinical syndromes, subclinical inflammation may promote the development of certain tumours. The
expression of COX-2 and lipid mediators of inflammation increases during the multistage progression of these
tumours. Non-steroidal anti-inflammatory drugs (NSAIDs), which inhibit COX-2 activity and tumour development in
many experimental and clinical settings, are inversely associated with certain cancers in epidemiological
studies. Despite their promise, however, anti-inflammatory drugs are not yet recommended for the prevention or
treatment of any cancers. Numerous questions must be resolved concerning their molecular and cellular targets of
action, efficacy, safety, treatment regimen, indications, and the balance of risks and benefits from treatment in
designated patient populations.
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Chemokine-based pathogenetic mechanisms in cancer
Ilaria Conti, Christine Dube and Barrett J. Rollins
Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02116 and Department
of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
The chemokine system has evolved primarily to control the trafficking of leukocytes during immune or inflammatory
responses. However, through their expression of chemokine ligands and receptors, cancers have commandeered
various aspects of this host defence system in order to enhance their growth. Although engineered
overexpression of some tumour-derived chemokines can stimulate host antitumour responses, this is unlikely to be
the reason that tumour cells express them. Rather, a growing body of clinical and laboratory evidence indicates
that cancer cells may secrete chemokines in order to attract host cells that supply the tumours with growth and
angiogenic factors. In addition, chemokine receptor expression by tumour cells may permit them to use the host’s
pre-existing leukocyte trafficking system to invade target tissues during metastatic spread. Together, these
observations suggest that therapies directed against chemokine ligands or receptors may be beneficial in cancer.
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Anti-TNFalpha therapy of rheumatoid arthritis: what can we learn about chronic disease?
Marc Feldmann, Fionula M. Brennan, Ewa Paleolog, Andrew Cope, Peter Taylor, Richard Williams, Jim Woody and
Ravinder N. Maini
Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology and
Medicine, 1 Aspenlea Road, London, W6 8LH, UK and Roche Bioscience, 3401 Hillview Avenue, Palo Alto, CA 94304,
USA
The importance of tumour necrosis factor (TNF)alpha in rheumatoid arthritis (RA) was initially proposed on the basis
of analysis of cytokine gene regulation at the local site of the disease, the synovium. This was then verified in
animal models and established in an extensive series of clinical trials, culminating in now
250 000 treated
patients with either of two approved TNF inhibitors, antibody or fusion protein. The degree and magnitude of
clinical benefit has enabled analyses of the mechanism by which anti-TNF benefits, and hence insights into
important steps in the disease process. It was found that essentially all aspects of RA were ameliorated, and
important mechanisms of benefit involved diminution of multiple pro-inflammatory cytokines, adhesion molecules
and chemokines, leading to reduced cell trafficking, reduced angiogenesis and most importantly halting of joint
destruction. What of the problems? Safety is better than prior drugs, but there is a small increase in severe
infections, smaller than might have been anticipated. Cost is the major drawback limiting greater use. In view of
the central pathological processes downregulated, and their role in many diseases, the early clinical success of
anti-TNF in RA led to subsequent successful trials and registration in Crohn’s disease and juvenile rheumatoid
arthritis, and successful trials in ankylosing spondylitis, psoriasis and psoriatic arthritis. The era of
anti-cytokine therapeutics is just dawning.
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How do chemokine/chemokine receptor activations affect tumorigenesis?
Ann Richmond, Guo Huang Fan, Punita Dhawan and Jinming Yang
Department of Veterans Affairs, Nashville, TN and Department of Cancer Biology, Vanderbilt University School of
Medicine, Nashville, TN 37232, USA
Cells that display chemokine receptors are capable of responding to a gradient of chemokine with a motility
response that can translate into a chemotactic response. This continuous response to the chemokine sometimes
requires that the chemokine receptor be internalized and recycled back to the membrane. We have shown that
ligand activation of the CXC chemokine receptor, CXCR2, results in movement of the receptor into clathrin coated
pits, followed by movement into the early endosome, the sorting endosome, then on to the recycling endosome prior
to trafficking back into the plasma membrane compartment. Prolonged exposure to saturating concentrations of the
ligand results in movement of a large percentage of the receptor into the late endosome and on to the lysosome
for degradation. Mutation of the receptor in a manner which impairs receptor internalization by altering the
binding of adaptor proteins AP-2 or β arrestin to CXCR2, results in a marked reduction in the chemotactic
response. Chemokine receptors also activate multiple intracellular signals that lead to the activation of the
transcription factor, nuclear factor κ beta (NF-κB). Transformation is often associated with a constitutive
activation of NF-κB, leading to endogenous expression of chemokines and their receptors. This creates an
autocrine loop which NF-κB in the activated state, and altered expression of factors that promote tumour
angiogenesis and escape from apoptosis. We have shown that the constitutive activation of NF-κB in human
melanoma tumours is accompanied by constitutive activation of the NF-κB inducing kinase (NIK) as well as the
constitutive activation of AKT. As these factors that modulate the expression of anti-apoptotic factors work
together, the tumour cells exhibit enhanced survival and growth. This never ending cycle of activation of NF-κB,
leading to enhanced production of chemokines, enhanced activation of AKT and NF-κB, and enhanced transcription of
inhibitors of apoptosis and chemokines, is one that has been used to foster the growth of the tumour to the
disadvantage of the host. Thus we propose that blocking CXCR2 and/or NF-κB offers potential therapeutic promise
for a number of chronic inflammatory conditions and cancers, including malignant melanoma.
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Proinflammatory cytokines, immune response and tumour progression
Michela Spadaro and Guido Forni
Department of Clinical and Biological Sciences, University of Torino, Ospedale San Luigi Gonzaga, 10043
Orbassano, Italy
Tumour cells naturally secrete proinflammatory cytokines and chemokines to interact with the microenvironment and
regulate neoangiogenesis. The repertoire of factors thus produced shapes tumour progression. However, experiments
in the mouse have shown that injection of a low pharmacological dose of a proinflammatory cytokine or chemokine
into the microenvironment increases the inflammatory reaction so enormously that locally activated leukocytes
inhibit or eradicate the tumour. Massive shrinkage of recurrent head and neck squamous cell carcinomas (SCC) and
prevention of recurrences after surgical removal of a primary SCC follow perilymphatic administration of low
doses of interleukin (IL)2, while low daily doses of IL12 markedly delay carcinogenesis in transgenic mice
predestined to die of mammary carcinomas and keep them tumour-free for long periods. The reaction elicited by
proinflammatory cytokines evidently has a great potential in tumour control.
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Lymphangiogenesis and tumour metastasis
Jean-Christophe Tille, Riccardo Nisato and Michael S. Pepper
Department of Cell Biology and Morphology, University Medical Center, 1 rue Michel Servet, 1211 Geneva 4,
Switzerland
The lymphatic system serves to collect and transport interstitial fluid (lymph) within tissues, and plays an
important role in the immune response. The lymphatic system also constitutes one of most important pathways of
tumour dissemination. In several human cancers, increased expression in primary tumours of a new member of the
vascular endothelial growth factor (VEGF) family, namely VEGF-C, is correlated with regional lymph node
metastasis. Experimental studies using transgenic mice overexpressing VEGF-C or xenotransplantation of
VEGF-C-expressing tumour cells into immunodeficient mice have demonstrated a role for VEGF-C in tumour
lymphangiogenesis and the subsequent formation of lymph node metastasis. However, there is at present very little
evidence for lymphangiogenesis in human tumours, which is at variance with the data obtained in animal models.
Nonetheless, the striking correlation between levels of VEGF-C in primary tumours and lymph node metastases
exists. This suggests that VEGF-C may activate pre-existing lymphatics which then become actively involved in
tumour cell chemotaxis, intralymphatic intravasation and distal dissemination. The role of VEGF-C in human tumour
metastasis is therefore likely to involve lymphangiogenesis as well as its capacity to induce activation of
pre-existing lymphatic endothelium.
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Infiltration of tumours by macrophages and dendritic cells: tumour-associated macrophages as a paradigm for
polarized M2 mononuclear phagocytes
Alberto Mantovani, Silvano Sozzani, Massimo Locati, Tiziana Schioppa, Alessandra Saccani, Paola Allavena and
Antonio Sica
Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157 Milan and Centro IDET, Institute of
General Pathology, University of Milan, Via Mangiagalli 31, 20133 Milan and Department of Biotechnology, Section
of General Pathology and Immunology, University of Brescia, 25123 Brescia, Italy
Macrophages and dendritic cells infiltrate tumours. In the tumour microenvironment, mononuclear phagocytes
acquire properties of polarized M2 (or alternatively activated) macrophages. These functionally polarized cells,
and similarly oriented or immature dendritic cells present in tumours, play a key role in subversion of adaptive
immunity and in inflammatory circuits which promote tumour growth and progression.
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The influence of CD25+ cells on the generation of immunity to tumour cell lines in mice
Emma Jones, Denise Golgher, Anna Katharina Simon, Michaela Dahm-Vicker, Gavin Screaton, Tim Elliott and Awen
Gallimore
Nuffield Department of Medicine, Oxford University and The Cancer Sciences Division, University of Southampton
and Medical Biochemistry and Immunology, University of Wales College of Medicine, UK
CD25+ regulatory T cells comprise 5–10% of CD4+ T cells in naïve mice and have been shown in several
in vivo
murine models to prevent the induction of autoimmune disease and inflammatory disease. Since T cells, which
mediate autoimmunity, can through recognition of self-antigens also target tumour cells, it was postulated that
CD25+ regulatory cells would also inhibit the generation of immune responses to tumours. Depletion of these cells
using CD25-specific monoclonal antibodies has indeed been shown to promote rejection of several transplantable
murine tumour cell lines including melanoma, leukaemia and colorectal carcinoma. Results obtained using these
models indicate that in the absence of regulatory cells, CD4+ T cells mediate tumour immunity, although the
precise mechanisms through which these cells result in tumour rejection have not yet been elucidated. The target
antigens recognized by these CD4+ T cells have also not yet been identified. Immunization of mice with tumour
cells in the absence of CD25+ regulatory cells does, however, induce immunity against a variety of different
tumour cell lines indicating that the target antigen(s) are shared amongst tumours of distinct histological
origins. Since CD25+ regulatory cells have been identified in humans, the possibility that the cells inhibit
immune responses to shared rejection antigens expressed by human tumours is worthy of investigation.
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Macrophages: modulators of breast cancer progression
Elaine Y. Lin and Jeffrey W. Pollard
Center for the Study of Reproductive Biology and Women's Health, Departments of Developmental and Molecular
Biology and Obstetrics, Gynecology and Women's Health, Albert Einstein College of Medicine, 1300 Morris Park, New
York, NY 10461, USA
In many solid tumour types the abundance of tumour associated macrophages (TAMs) is correlated with poor
prognosis. Macrophages are recruited through the local expression of chemoattractants such as colony stimulating
factor 1 (CSF-1) and macrophage chemoattractant protein 1. Over-expression of both of these factors is
correlated with poor prognosis in a variety of tumours. Macrophages also play an important physiological role in
the development and function of many tissues ranging from the brain to the mammary gland. Thus we hypothesized
that TAMs are recruited to tumours through the expression of potent chemoattractants and in this site their
normal trophic functions are subverted to promote tumour progression and metastasis. To test this hypothesis we
crossed mice deficient in macrophages owing to being homozygous for a null mutation in the CSF-1 gene with mice
pre-disposed to mammary cancer due to the epithelial restricted expression of the polyoma middle T oncoprotein.
The absence of macrophages did not change the incidence or growth of the primary tumour but decreased its rate of
progression and inhibited metastasis. These data are explicable through the known macrophage functions in matrix
re-modelling, angiogenesis as well as stimulation of tumour growth and motility through the synthesis of growth
and chemotactic factors. Interestingly, these functions are also normally found in wound healing or
pathologically during chronic inflammation. This supports the notion that tumours are ‘wounds that never heal’
and suggests that chronic inflammation though persistent infection or by other means might be an important
co-factor in the genesis and promotion of tumours. Macrophages might therefore be important targets for cancer
therapies.
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Chemokines: angiogenesis and metastases in lung cancer
Robert M. Strieter, John A. Belperio, Roderick J. Phillips, and Michael P. Keane
Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, Los Angeles,
David Geffen School of Medicine, UCLA, 900 Veteran Avenue, 14–154 Warren Hall, Box 711922, Los Angeles, CA 90024
Non-small cell lung cancer (NSCLC) growth, angiogenesis, invasion, and metastases to specific organs is dependent
on an orchestrated series of events that include: cellular transformation; establishment of a pro-angiogenic
environment; tumour cell proliferation, invasion and entry into the circulation; and tumour cell trafficking and
metastatic tumour growth in specific organs based on concept of Paget’s theory of ‘seed and soil’ related to
homing of tumour cells to a specific organ. The events that destine a tumour cell to invade and metastasize to
distant organs are analogous to leukocyte trafficking. Chemokines have had an increasingly important role in
mediating the homing of leukocytes under both conditions of homeostasis and inflammatory/immunological responses.
Recently, the biology of chemokines have extended beyond their role in mediating leukocyte trafficking.
Specifically, CXC chemokines have been found to be important in the regulation of angiogenesis, and in promoting
tumour cell migration and organ-specific metastases. Data will be presented to highlight the importance of CXC
chemokine ligands and receptors in mediating NSCLC tumour-associated angiogenesis, ‘immunoangiostasis’, and organ
specific metastases. These findings may ultimately lead to clinical strategies to attenuate the pathobiology of
CXC chemokines in promoting NSCLC tumour growth and metastases.
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Macrophage infiltration and angiogenesis in human malignancy
Helen Knowles, Russell Leek and Adrian L Harris
Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine and Nuffield
Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
It is well recognized that human tumours are hypoxic compared to normal adjacent tissues and the hypoxia is
related to a poor outcome regardless of modality of treatment, including surgery alone, radiotherapy or
chemotherapy. Hypoxia regulates the complex programme of gene transcription via hypoxia-inducible factors 1 and 2
(HIF-1, -2). We have shown that in breast cancer and many other tumour types, the macrophages have a high
expression of HIF-2α compared to normal tissue macrophages and compared to the tumour. This is an independent
prognostic factor for poor outcome having macrophages with high HIF-2α. The mechanisms
up regulating HIF-2α in
macrophages may be through inflammatory cytokines as well as hypoxia. Differentiation of monocytes into
macrophages increases the basal level of HIF-2α protein. In addition, there are many changes in the basal gene
programme regulated by hypoxia and the ability to induce them by hypoxia. Many of these genes are involved in
inflammation and angiogenesis. Thus, the conversion of a peripheral monocyte into a macrophage generates a
complex new programme of hypoxia-responsive genes that may contribute to the angiogenesis and complex
microenvironment within the tumour, and as such provides important targets for therapy.
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The role of inflammation for tumour growth and tumour suppression
Thomas Blankenstein
Max-Delbrück-Centrum for Molecular Medicine, Robert-Rössle Strasse 10, 13092 Berlin and Institute of Immunology,
Free University Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
The relationship between inflammation and tumour growth is poorly understood. The quality, quantity and time
point of the inflammatory response may decide whether inflammation supports or inhibits tumour growth. Three
examples are given that illustrate the different role of inflammation for tumour growth. It will be shown that
tumour infiltrating macrophages can contribute to tumour rejection, can be essential for tumour growth or can
occur as innocent bystander cells in tumours. Then it will be shown that the timely arrival of T cells at the
tumour site is critical for tumour rejection and that non-bone marrow-derived tumour stroma cells are important
targets during tumour rejection. Finally, a protective inflammatory response against the chemical carcinogen
methylcholanthrene (MCA) will be discussed. This response is related to a tissue repair response induced by the
tissue damaging effects of the carcinogen in the course of which MCA is encapsulated and no longer able to induce
tumours.
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Cyclooxygenase 2: from inflammation to carcinogenesis
Ari Ristimäki
Department of Pathology, Helsinki University Central Hospital and Molecular and Cancer Biology Research Program,
Biomedicum Helsinki, University of Helsinki, Finland
Cyclooxygenase (COX) is the rate-limiting enzyme in the conversion of arachidonic acid to prostanoids. Two COX
isoforms have been cloned, of which COX-1 is constitutively expressed, while the expression of COX-2 is low or
nondetectable in most tissues, but can be readily induced in response to cell activation by cytokines, growth
factors and tumour promoters. Thus, COX-1 is considered a housekeeping gene and thought to be responsible for the
synthesis of prostanoids involved in cytoprotection of the stomach and for the production of the proaggregatory
prostanoid thromboxane by the platelets. In contrast, COX-2 is an inducible, immediate-early gene, and its role
has been related to inflammation, reproduction and carcinogenesis. Expression of COX-2 is elevated in a variety
of human malignancies and in their precursor lesions. Furthermore, genetic deletion or pharmacological inhibition
of COX-2 suppresses tumour growth in several animal models of carcinogenesis. In humans, elevated COX-2
expression associated with poor prognosis in adenocarcinomas of the digestive tract and the breast, and a
selective inhibitor of COX-2 reduced polyp burden in patients who suffer from familial adenomatous polyposis.
Thus, COX-2 seems to be a relevant target in chemoprevention.
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The inflammatory cytokine network of epithelial cancer: therapeutic implications
Pieter Szlosarek and Fran Balkwill
Cancer Research UK, Translational Oncology Laboratory, Barts and The London, Queen Mary’s School of Medicine and
Dentistry, John Vane Science Centre, London EC1M 6BQ, UK
A network of inflammatory cytokines and chemokines is found in epithelial cancer. There is evidence that these
mediators contribute not only to tumour cell growth and survival, but also to communication between the cancer
cells and stromal elements. Tumour cell production of the inflammatory cytokine tumour necrosis factor alpha (TNFα)
is one critical factor in this autocrine and paracrine network. TNFalpha may also initiate and sustain production of
other cytokines and chemokines. Chemokines are key determinants of the leukocyte infiltrate in solid ovarian
tumours and influence the extent and phenotype of the infiltrate in ascitic disease. Chemokines may also be
involved in tumour cell spread. Thus some of the processes involved in chronic inflammation are also active in
human epithelial cancers. Agents that antagonise TNFalpha or chemokines are currently being assessed in preclinical
animal cancer models and in phase I clinical trials.
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In vivo manipulation of dendritic cell migration and activation to elicit antitumour immunity
Alain P. Vicari, Béatrice Vanbervliet, Catherine Massacrier, Claudia Chiodoni, Céline Vaure, Smina Aït-Yahia,
Christophe Dercamp, Fabien Matsos, Olivier Reynard, Catherine Taverne, Philippe Merle, Mario P. Colombo, Anne
O’Garra, Giorgio Trinchieri and Christophe Caux
Schering-Plough Laboratory for Immunological Research, 69571 Dardilly, France, Department of Experimental
Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori, 20133 Milano, Italy, INSERM U271, 69424 Lyon,
France, and DNAX Research Institute, Palo Alto, CA 94304, USA
Two approaches have been pursued to elicit antitumour immunity: (i) induce recruitment of immature dendritic
cells or their precursors at a site of antigen delivery, and (ii) induce activation of tumour-infiltrating
dendritic cells (DCs). The recruitment of selected DC subtype conditions the class of the immune response. Each
immature DC population displays a unique spectrum of chemokine responsiveness. For examples, Langerhans cells
(LCs) migrate selectively in response to CCL20/MIP-3alpha (through CCR6), blood CD11c+ DC to MCP chemokines (through
CCR2). All these chemokines are inducible upon inflammatory stimuli. CCL20/MIP-3alpha in particular is only detected
within inflamed epithelium, at site of antigen entry, which is infiltrated by immature DCs. Furthermore, to reach
the site of injury, sequential responsiveness might operate, blood DC precursors are recruited by a set of
chemokines (MIP, MCP) while within the tissue other chemokines will direct their navigation
(CCL20/MIP-3alpha). Of
interest, when injected in vivo together with antigen, MCP-4/CCL13, but not
CCL20/MIP-3alpha, recruits blood
monocytes or blood DC precursors that promptly differentiate into typical DCs and that improve antitumour immune
responses. After antigen uptake, DCs acquire, upon maturation, responsiveness to CCR7 ligands (CCL21/SLC/6Ckine,
CCL19/ELC/MIP-3beta) due to receptor up-regulation. In particular, in the periphery, CCL21/SLC/6Ckine expressed by
lymphatic vessels may direct into the lymph stream, antigen-loaded maturing DCs leaving the site of infection;
while within in lymph-node, CCL21/SLC/6Ckine plays a critical role in the entry of naïve T cells from the blood
through HEV. In regard to its central role, we decided to investigate whether the expression of CCL21/SLC/6Ckine
in tumour may lead to antitumour immune responses. C26 colon carcinoma tumour cell line transduced with
CCL21/SLC/6Ckine showed reduced tumorigenicity when injected in vivo into immunocompetent mice. The protection
was CD8 dependent and associated with an important intratumoral infiltration of DC. Most tumour infiltrating DCs
(TIDCs) had an immature phenotype, were able to present TAA in the context of MHC class I, but were refractory to
stimulation with the combination of LPS, IFNgamma and anti-CD40 antibody. TIDC paralysis could be reverted, however,
by in vitro or in vivo stimulation with the combination of a CpG immunostimulatory sequence and an
anti-interleukin 10 receptor (IL10R) antibody. CpG or anti-IL10R alone were inactive in TIDC, while CpG triggered
activation in normal DC. In particular, CpG plus anti-IL10R enhanced the TAA-specific immune response and
triggered de novo IL-12 production. Subsequently, CpG plus anti-IL10R treatment showed robust antitumour
therapeutic activity exceeding by far that of CpG alone, and elicited antitumour immune memory.
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