Showing papers in "Nature Reviews Cancer in 2004"
TL;DR: In this article, the authors propose that persistent metabolism of glucose to lactate even in aerobic conditions is an adaptation to intermittent hypoxia in pre-malignant lesions, which leads to microenvironmental acidosis requiring evolution to phenotypes resistant to acid-induced cell toxicity.
Abstract: If carcinogenesis occurs by somatic evolution, then common components of the cancer phenotype result from active selection and must, therefore, confer a significant growth advantage. A near-universal property of primary and metastatic cancers is upregulation of glycolysis, resulting in increased glucose consumption, which can be observed with clinical tumour imaging. We propose that persistent metabolism of glucose to lactate even in aerobic conditions is an adaptation to intermittent hypoxia in pre-malignant lesions. However, upregulation of glycolysis leads to microenvironmental acidosis requiring evolution to phenotypes resistant to acid-induced cell toxicity. Subsequent cell populations with upregulated glycolysis and acid resistance have a powerful growth advantage, which promotes unconstrained proliferation and invasion.
4,361 citations
TL;DR: Highly dynamic mitotic-spindle microtubules are among the most successful targets for anticancer therapy, and it is now known that at lower concentrations, microtubule-targeted drugs can suppress micro Tubule dynamics without changingmicrotubule mass; this action leads to mitotic block and apoptosis.
Abstract: Highly dynamic mitotic-spindle microtubules are among the most successful targets for anticancer therapy. Microtubule-targeted drugs, including paclitaxel and Vinca alkaloids, were previously considered to work primarily by increasing or decreasing the cellular microtubule mass. Although these effects might have a role in their chemotherapeutic actions, we now know that at lower concentrations, microtubule-targeted drugs can suppress microtubule dynamics without changing microtubule mass; this action leads to mitotic block and apoptosis. In addition to the expanding array of chemically diverse antimitotic agents, some microtubule-targeted drugs can act as vascular-targeting agents, rapidly depolymerizing microtubules of newly formed vasculature to shut down the blood supply to tumours.
4,007 citations
TL;DR: Gaining a better understanding of the relationship between obesity and cancer can provide new insight into mechanisms of cancer pathogenesis.
Abstract: The prevalence of obesity is rapidly increasing globally. Epidemiological studies have associated obesity with a range of cancer types, although the mechanisms by which obesity induces or promotes tumorigenesis vary by cancer site. These include insulin resistance and resultant chronic hyperinsulinaemia, increased bioavailability of steroid hormones and localized inflammation. Gaining a better understanding of the relationship between obesity and cancer can provide new insight into mechanisms of cancer pathogenesis.
3,281 citations
TL;DR: A 'census' of cancer genes is conducted that indicates that mutations in more than 1% of genes contribute to human cancer.
Abstract: A central aim of cancer research has been to identify the mutated genes that are causally implicated in oncogenesis ('cancer genes'). After two decades of searching, how many have been identified and how do they compare to the complete gene set that has been revealed by the human genome sequence? We have conducted a 'census' of cancer genes that indicates that mutations in more than 1% of genes contribute to human cancer. The census illustrates striking features in the types of sequence alteration, cancer classes in which oncogenic mutations have been identified and protein domains that are encoded by cancer genes.
3,136 citations
TL;DR: Macrophages are educated by the tumour microenvironment, so that they adopt a trophic role that facilitates angiogenesis, matrix breakdown and tumour-cell motility — all of which are elements of the metastatic process.
Abstract: Evidence from clinical and experimental studies indicates that macrophages promote solid-tumour progression and metastasis. Macrophages are educated by the tumour microenvironment, so that they adopt a trophic role that facilitates angiogenesis, matrix breakdown and tumour-cell motility — all of which are elements of the metastatic process. During an inflammatory response, macrophages also produce many compounds — ranging from mutagenic oxygen and nitrogen radicals to angiogenic factors — that can contribute to cancer initiation and promotion. Macrophages therefore represent an important drug target for cancer prevention and cure.
3,130 citations
TL;DR: Solid tumours contain regions at very low oxygen concentrations (hypoxia), often surrounding areas of necrosis, which provides an opportunity for tumour-selective therapy, including prodrugs activated by Hypoxia, hypoxia-specific gene therapy, targeting the hypoxIA-inducible factor 1 transcription factor, and recombinant anaerobic bacteria.
Abstract: Solid tumours contain regions at very low oxygen concentrations (hypoxia), often surrounding areas of necrosis. The cells in these hypoxic regions are resistant to both radiotherapy and chemotherapy. However, the existence of hypoxia and necrosis also provides an opportunity for tumour-selective therapy, including prodrugs activated by hypoxia, hypoxia-specific gene therapy, targeting the hypoxia-inducible factor 1 transcription factor, and recombinant anaerobic bacteria. These strategies could turn what is now an impediment into a significant advantage for cancer therapy.
2,428 citations
TL;DR: This timeline traces the field from its conception to the present day and addresses the genetic basis of epigenetic changes — an emerging area that promises to unite cancer genetics and epigenetics, and might serve as a model for understanding the epigenetic basis of human disease more generally.
Abstract: Since its discovery in 1983, the epigenetics of human cancer has been in the shadows of human cancer genetics. But this area has become increasingly visible with a growing understanding of specific epigenetic mechanisms and their role in cancer, including hypomethylation, hypermethylation, loss of imprinting and chromatin modification. This timeline traces the field from its conception to the present day. It also addresses the genetic basis of epigenetic changes — an emerging area that promises to unite cancer genetics and epigenetics, and might serve as a model for understanding the epigenetic basis of human disease more generally.
2,240 citations
TL;DR: Insight is provided into host–tumour interactions, such as the role of the leukocyte infiltrate, and into the mechanisms that determine the metastatic potential and site-specific spread of cancer cells.
Abstract: A complex network of chemokines and their receptors influences the development of primary tumours and metastases. New information about the biological role of chemokines in these processes is providing insights into host–tumour interactions, such as the role of the leukocyte infiltrate, and into the mechanisms that determine the metastatic potential and site-specific spread of cancer cells. Chemokine-receptor antagonists are showing promise in animal models of inflammation and autoimmune disease. Could manipulating the local chemokine network have therapeutic benefits in malignant disease?
2,214 citations
TL;DR: Tumour cells acquire the ability to proliferate uncontrollably, resist apoptosis, sustain angiogenesis and evade immune surveillance, and STAT proteins — especially STAT3 and STAT5 — regulate all of these processes and are persistence activated in a surprisingly large number of human cancers.
Abstract: Tumour cells acquire the ability to proliferate uncontrollably, resist apoptosis, sustain angiogenesis and evade immune surveillance. STAT proteins — especially STAT3 and STAT5 — regulate all of these processes and are persistently activated in a surprisingly large number of human cancers. Consequently, STAT proteins are emerging — unexpectedly — as ideal targets for cancer therapy.
2,203 citations
TL;DR: The link between EBV and 'endemic' Burkitt's lymphoma proved consistent and became the first of an unexpectedly wide range of associations discovered between this virus and tumours.
Abstract: Epstein–Barr virus (EBV) was discovered 40 years ago from examining electron micrographs of cells cultured from Burkitt's lymphoma, a childhood tumour that is common in sub-Saharan Africa, where its unusual geographical distribution — which matches that of holoendemic malaria —indicated a viral aetiology. However, far from showing a restricted distribution, EBV — a γ-herpesvirus — was found to be widespread in all human populations and to persist in the vast majority of individuals as a lifelong, asymptomatic infection of the B-lymphocyte pool. Despite such ubiquity, the link between EBV and 'endemic' Burkitt's lymphoma proved consistent and became the first of an unexpectedly wide range of associations discovered between this virus and tumours.
2,032 citations
TL;DR: This work highlights a key role for interactions between hyaluronan and tumour cells in several aspects of malignancy and indicates the possibility of new therapeutic strategies.
Abstract: Hyaluronan is an extracellular and cell-surface-associated polysaccharide that is traditionally regarded as a biological 'goo' that participates in lubricating joints or holding together gel-like connective tissues. Although these are common physiological roles of hyaluronan in adult organisms, hyaluronan also functions as a microenvironmental cue that co-regulates cell behaviour during embryonic development, healing processes, inflammation and tumour development. Recent work highlights a key role for interactions between hyaluronan and tumour cells in several aspects of malignancy and indicates the possibility of new therapeutic strategies.
TL;DR: Lowering the tumour IFP with specific signal-transduction antagonists might be a useful approach to improving anticancer drug efficacy.
Abstract: Many solid tumours show an increased interstitial fluid pressure (IFP), which forms a barrier to transcapillary transport. This barrier is an obstacle in tumour treatment, as it results in inefficient uptake of therapeutic agents. There are a number of factors that contribute to increased IFP in the tumour, such as vessel abnormalities, fibrosis and contraction of the interstitial matrix. Lowering the tumour IFP with specific signal-transduction antagonists might be a useful approach to improving anticancer drug efficacy.
TL;DR: The restricted view of tumour progression as a multistep process defined by the accumulation of mutations in cancer cells has largely ignored the substantial contribution of the tumour microenvironment to malignancy.
Abstract: The restricted view of tumour progression as a multistep process defined by the accumulation of mutations in cancer cells has largely ignored the substantial contribution of the tumour microenvironment to malignancy. Even though the seed and soil hypothesis of Paget dates to 1889, it has been less than two decades since researchers have included the tumour microenvironment in their analyses of tumour progression. What have we recently learned from studying tumour-stroma interactions, and will this help to define new targets for therapy?
TL;DR: Mucins — large extracellular proteins that are heavily glycosylated with complex oligosaccharides — establish a selective molecular barrier at the epithelial surface and engage in morphogenetic signal transduction.
Abstract: Mucins — large extracellular proteins that are heavily glycosylated with complex oligosaccharides — establish a selective molecular barrier at the epithelial surface and engage in morphogenetic signal transduction. Alterations in mucin expression or glycosylation accompany the development of cancer and influence cellular growth, differentiation, transformation, adhesion, invasion and immune surveillance. Mucins are used as diagnostic markers in cancer, and are under investigation as therapeutic targets for cancer.
TL;DR: There are properties that define 'BRCAness' — that is, traits that some sporadic cancers share with those occurring in either BRCA1- or BRCa2-mutation carriers, which might have important implications for the clinical management of these cancers.
Abstract: Germline mutations in the BRCA1, BRCA2 and Fanconi anaemia genes confer cancer susceptibility, and the proteins encoded by these genes have distinct functions in related DNA-repair processes. Emerging evidence indicates that these processes are disrupted by numerous mechanisms in sporadic cancers. Collectively, there are properties that define 'BRCAness' — that is, traits that some sporadic cancers share with those occurring in either BRCA1- or BRCA2-mutation carriers. These common properties might have important implications for the clinical management of these cancers.
TL;DR: Converging results from epidemiological research and in vivo carcinogenesis models indicate that high levels of circulating IGF1 are associated with increased risk of several common cancers, and ongoing research seeks to clarify the mechanisms underlying these observations.
Abstract: The insulin-like growth factor 1 (IGF1) signalling pathway has important roles in regulating cellular proliferation and apoptosis. Converging results from epidemiological research and in vivo carcinogenesis models indicate that high levels of circulating IGF1 are associated with increased risk of several common cancers. Ongoing research seeks to clarify the mechanisms underlying these observations and to determine the extent to which IGF physiology influences patterns of cancer incidence. Various therapeutic strategies that target the IGF1 receptor have demonstrated impressive antineoplastic activity in laboratory models, and clinical trials of several novel drug candidates are planned.
TL;DR: The mixture of cytokines that is produced in the tumour microenvironment has an important role in cancer pathogenesis and provides new opportunities for improving cancer immunotherapy.
Abstract: The mixture of cytokines that is produced in the tumour microenvironment has an important role in cancer pathogenesis. Cytokines that are released in response to infection, inflammation and immunity can function to inhibit tumour development and progression. Alternatively, cancer cells can respond to host-derived cytokines that promote growth, attenuate apoptosis and facilitate invasion and metastasis. A more detailed understanding of cytokine–tumour-cell interactions provides new opportunities for improving cancer immunotherapy.
TL;DR: Gaining better insight into the mechanisms of these effects could lessen or even eliminate the empiricism used to determine the optimal dose and schedule for metronomic chemotherapy regimens.
Abstract: In addition to proliferating cancer cells and various types of normal cells, such as those of the bone marrow, conventional cytotoxic chemotherapeutics affect the endothelium of the growing tumour vasculature. The anti-angiogenic efficacy of chemotherapy seems to be optimized by administering comparatively low doses of drug on a frequent or continuous schedule, with no extended interruptions — sometimes referred to as 'metronomic' chemotherapy. In addition to reduced acute toxicity, the efficacy of metronomic chemotherapy seems to increase when administered in combination with specific anti-angiogenic drugs. Gaining better insight into the mechanisms of these effects could lessen or even eliminate the empiricism used to determine the optimal dose and schedule for metronomic chemotherapy regimens.
TL;DR: In addition to the role of rapamycin as an immune suppressant, emerging data indicate that genetic and metabolic changes accompanying malignant transformation might cause hypersensitivity to TOR inhibition.
Abstract: Rapamycin, a macrocyclic lactone, is a highly specific inhibitor of the serine/threonine protein kinase target of rapamycin (TOR). Although it is clear that TOR controls initiation of protein translation, recent results indicate that TOR is a central controller, integrating a plethora of signalling pathways that respond to growth factors and nutritional status. In addition to the role of rapamycin as an immune suppressant, emerging data indicate that genetic and metabolic changes accompanying malignant transformation might cause hypersensitivity to TOR inhibition.
TL;DR: In addition to their adhesive functions, cell-adhesion molecules modulate signal-transduction pathways by interacting with molecules such as receptor tyrosine kinases, components of the WNT signalling pathway and RHO-family GTPases, which have a crucial role in tumour progression.
Abstract: In addition to their adhesive functions, cell-adhesion molecules modulate signal-transduction pathways by interacting with molecules such as receptor tyrosine kinases, components of the WNT signalling pathway and RHO-family GTPases. So, changes in the expression of cell-adhesion molecules affect not only the adhesive repertoire of a cell, but also its signal-transduction status. Conversely, signalling pathways can modulate the function of cell-adhesion molecules, altering the interactions between cells and their environment. Recent experimental evidence indicates that such processes have a crucial role in tumour progression, in particular during invasion and metastasis.
TL;DR: The detection and characterization of disseminated tumour cells in patients with cancer has provided important new information about the cascade of metastatic events and has important implications for cancer prognosis and for therapy.
Abstract: Despite recent progress in gene-expression profiling studies, the biology underlying the various patterns of metastasis that are observed in different tumour types remains unclear. The detection and characterization of disseminated tumour cells in patients with cancer has provided important new information about the cascade of metastatic events. This information has important implications for cancer prognosis and for therapy.
TL;DR: A thorough understanding of p53 will be extremely useful in the development of new strategies for treating and preventing cancer, including restoration of p 53 function and selective killing of tumours with mutant TP53.
Abstract: Interest in the tumour suppressor p53 has generated much information regarding the complexity of its function and regulation in carcinogenesis. However, gaps still exist in our knowledge regarding the role of p53 post-translational modifications in carcinogenesis and cancer prevention. A thorough understanding of p53 will be extremely useful in the development of new strategies for treating and preventing cancer, including restoration of p53 function and selective killing of tumours with mutant TP53.
TL;DR: The characterization of both the molecular architecture of receptor tyrosine kinases and the main functions of these proteins and their ligands in tumorigenesis opened the door to a new era in molecular oncology and paved the way to the development of the first target-specific cancer therapeutics.
Abstract: Receptor tyrosine kinases are a subclass of cell-surface growth-factor receptors with an intrinsic, ligand-controlled tyrosine-kinase activity. They regulate diverse functions in normal cells and have a crucial role in oncogenesis. Twenty years ago, the first primary structure of a receptor tyrosine kinase, the epidermal growth factor receptor, was elucidated. The characterization of both the molecular architecture of receptor tyrosine kinases and the main functions of these proteins and their ligands in tumorigenesis opened the door to a new era in molecular oncology and paved the way to the development of the first target-specific cancer therapeutics.
TL;DR: This work has shown that ceramide — a central molecule in sphingolipid metabolism — in effect functions as a tumour-suppressor lipid, inducing antiproliferative and apoptotic responses in various cancer cells, and that S1P induces responses that, on aggregate, render S 1P a tumours-promoting lipid.
Abstract: Biologically active sphingolipids have key roles in the regulation of several fundamental biological processes that are integral to cancer pathogenesis. Recent significant progress in understanding biologically active sphingolipid synthesis, specifically within ceramide and sphingosine-1-phosphate (S1P)-mediated pathways, has identified crucial roles for these molecules both in cancer development and progression. Ceramide — a central molecule in sphingolipid metabolism — in effect functions as a tumour-suppressor lipid, inducing antiproliferative and apoptotic responses in various cancer cells. Conversely, S1P induces responses that, on aggregate, render S1P a tumour-promoting lipid. These discoveries are paving the way for the advancement of anticancer therapies.
TL;DR: A proteasome inhibitor — bortezomib — has been developed that has shown efficacy as an anticancer agent in the clinic and how can targeting such a universal, broadly active cellular component provide the selectivity and specificity that are required for cancer therapeutics?
Abstract: The proteasome is an abundant multi-enzyme complex that provides the main pathway for degradation of intracellular proteins in eukaryotic cells. As such, it controls the levels of proteins that are important for cell-cycle progression and apoptosis in normal and malignant cells; for example, cyclins, caspases, BCL2 and nuclear factor of κB. A proteasome inhibitor — bortezomib — has been developed that has shown efficacy as an anticancer agent in the clinic. How can targeting such a universal, broadly active cellular component provide the selectivity and specificity that are required for cancer therapeutics?
TL;DR: A key role of c-SRC in cancer seems to be to promote invasion and motility, functions that might contribute to tumour progression.
Abstract: The c-SRC non-receptor tyrosine kinase is overexpressed and activated in a large number of human malignancies and has been linked to the development of cancer and progression to distant metastases. These observations have led to the recent targeting of c-SRC for the development of anticancer therapeutics, which show promise as a new avenue for cancer treatment. Despite this, however, the precise functions of c-SRC in cancer remain unclear. In addition to increasing cell proliferation, a key role of c-SRC in cancer seems to be to promote invasion and motility, functions that might contribute to tumour progression.
TL;DR: The RAS–mitogen activated protein kinase (MAPK) signalling pathway has long been viewed as an attractive pathway for anticancer therapies, based on its central role in regulating the growth and survival of cells from a broad spectrum of human tumours.
Abstract: The RAS-mitogen activated protein kinase (MAPK) signalling pathway has long been viewed as an attractive pathway for anticancer therapies, based on its central role in regulating the growth and survival of cells from a broad spectrum of human tumours. Small-molecule inhibitors designed to target various steps of this pathway have entered clinical trials. What have we recently learned about their safety and effectiveness? Will the MAPK pathway prove amenable to therapeutic intervention?
TL;DR: The mitotic-checkpoint molecule survivin — the inactivation of which induces the death of p53-deficient cells by mitotic catastrophe — is of particular interest.
Abstract: Defects in cell-death pathways are hallmarks of cancer. Although resistance to apoptosis is closely linked to tumorigenesis, tumour cells can still be induced to die by non-apoptotic mechanisms, such as necrosis, senescence, autophagy and mitotic catastrophe. The molecular pathways that underlie these non-apoptotic responses remain unclear. Several apoptotic and non-apoptotic pathways of cell death have been defined in normal physiology and during tumorigenesis, and these could potentially be manipulated to develop new cancer therapies. The mitotic-checkpoint molecule survivin — the inactivation of which induces the death of p53-deficient cells by mitotic catastrophe — is of particular interest.
TL;DR: DNA hypermethylation in CpG-rich promoters is now recognized as a common feature of human neoplasia, and CIMP-associated cancers seem to have a distinct epidemiology, a distinct histology, distinct precursor lesions and distinct molecular features.
Abstract: DNA hypermethylation in CpG-rich promoters is now recognized as a common feature of human neoplasia. However, the pathophysiology of hyper-methylation (why, when, where) remains obscure. Cancers can be classified according to their degree of methylation, and those cancers with high degrees of methylation (the CpG island methylator phenotype, or CIMP) represent a clinically and aetiologically distinct group that is characterized by 'epigenetic instability'. Furthermore, CIMP-associated cancers seem to have a distinct epidemiology, a distinct histology, distinct precursor lesions and distinct molecular features.
TL;DR: The identification of the molecular events that lead to treatment-induced mucosal injury has provided targets for mechanistically based interventions to prevent and treat mucositis.
Abstract: Oral and gastrointestinal mucositis is a toxicity of many forms of radiotherapy and chemotherapy. It has a significant impact on health, quality of life and economic outcomes that are associated with treatment. It also indirectly affects the success of antineoplastic therapy by limiting the ability of patients to tolerate optimal tumoricidal treatment. The complex pathogenesis of mucositis has only recently been appreciated and reflects the dynamic interactions of all of the cell and tissue types that comprise the epithelium and submucosa. The identification of the molecular events that lead to treatment-induced mucosal injury has provided targets for mechanistically based interventions to prevent and treat mucositis.