Inflammation and cancer

Harnessing host immune responses to preneoplasia: promise and challenges

Preneoplastic lesions are more common than clinical cancer and define a population at increased risk for the development of malignancy. Recent studies suggest that the immune system has the capacity to recognize these lesions, and enrichment of preneoplasia-specific immune effectors can be detected in the tumor bed of some preneoplastic lesions such as monoclonal gammopathies. Here, I discuss the promise and challenges of harnessing the immune response against preneoplasia. Approaches to boost the natural host response to these lesions may have a major impact on reducing net cancer burden.

Post-prenylation-processing enzymes as new targets in oncogenesis

RAS and many other oncogenic proteins undergo a complex series of post-translational modifications that are initiated by the addition of an isoprenoid lipid through a process known as prenylation. Following prenylation, these proteins usually undergo endoproteolytic processing by the RCE1 protease and then carboxyl methylation by a unique methyltransferase known as isoprenylcysteine carboxyl methyltransferase (ICMT). Although inhibitors that have been designed to target the prenylation step are now in advanced-stage clinical trials, their utility and efficacy seem to be limited. Recent findings, however, indicate that the inhibition of these post-prenylation-processing steps--particularly that of ICMT-catalysed methylation--might provide a better approach to the control of cancer-cell proliferation.

Role of inflammation in mouse lung tumorigenesis: a review

Peritumoral and intratumoral macrophages are associated with human and mouse lung cancer The mouse model allows manipulation of the macrophage population to experimentally evaluate its contribution to tumor growth. Genetic and pharmacologic strategies also permit testing the invol vement of specific inflammatory mediators in tumor progression. Among those endogenous mediators thus identified are interleukin (IL)-10, glucocorticoids, prostacyclin, nitric oxide, and surfactant apoprotein D (SP-D); serum SP-D levels are a useful biomarker to monitor tumor growth rate. The importance of understanding the mutually antagonistic roles of individual prostaglandins downstream from cycloxygenase (COX) and how this affects the efficacy of COX-inhibitory drugs is discussed. Promising drug candidates include synthetic glucocorticoids such as budesonide and the sulfone derivative of sulindac, apotosyn.

Age-promoted creation of a pro-cancer microenvironment by inflammation: pathogenesis of dyscoordinated feedback control

Aging and local chronic inflammation are established risk factors for epithelial tumorigenesis. These risk factors can act individually and/or synergistically to increase the incidence of age-related carcinomas. The basis for this co-stimulatory response has not yet been defined, nor have the feedback mechanisms that are responsible for this synergism. This review provides insight into the age-stimulated dysregulation of coordination of feedbacks in oxygen-, heme-, and proteolysis-dependent metabolic pathways caused by acute and chronic inflammation, and its role as a possible pathological basis for the creation of a pro-cancer microenvironment (PCM). The PCM facilitates the selective survival and growth of transformed cells (in a manner similar to a cancer-supportive microenvironment (CM)). The cancer-induced environment has certain features in common with chronic inflammatory-induced PCM. Namely, there are: enhanced oxidative cell resistance against apoptosis, increased production of matrix-degrading enzymes, switching to glycolytic metabolism, angiogenesis and vasorelaxation thus providing nutrient delivery, but restriction of the immune cell mobilization and/or its activation. The hypothetical model of PCM-genesis is presented as a result of enzymatic dysregulation of feedback control including oxygen-, heme-, prostaglandin E(2)-, metalloproteinase-9-, and NO/CO-dependent pathways. PCM-genesis takes place between the growth-inhibiting (cytotoxic) and growth promoting (regenerative) stages of inflammatory response. According to this model, age-related metabolic changes create opportunities for chronic (not acute) inflammatory response, which supports the PCM-condition with the non-healing wound state that often occurs around carcinomas.

High invasive melanoma cells induce matrix metalloproteinase-1 synthesis in fibroblasts by interleukin-1alpha and basic fibroblast growth factor-mediated mechanisms

Tumor invasion and metastasis of melanoma have been shown to require proteolytic degradation of the extracellular environment, achieved primarily by enzymes of the matrix metalloproteinases (MMP) family. Increased enzyme activity is localized at the border of tumor cells and the adjacent peritumoral connective tissue, emphasizing the crucial role of tumor-stroma interactions in the regulation of MMP activity. To analyze whether direct cell-cell contacts of melanoma cells and stromal fibroblasts or whether soluble factors, secreted by melanoma cells are involved in the regulation of MMP, we used different in vitro co-culture systems. Both direct and indirect co-cultures of high invasive BLM melanoma cells and human dermal fibroblasts resulted in an induction of pro-MMP-1 synthesis. Medium conditioned by BLM cells strongly induced pro-MMP-1 synthesis in fibroblasts, indicating the importance of diffusible factors for this induction. Competition by recombinant human interleukin (IL)-1 receptor antagonist, neutralizing IL-1alpha and basic fibroblast growth factor (bFGF) antibodies, resulted in a concentration-dependent reduction of pro-MMP-1 synthesis. Taken together, our results indicate an essential role for soluble factors, mainly IL-1alpha and bFGF, in the stimulation of dermal fibroblasts by human melanoma cells to secrete MMP-1.

ADVANCES IN CANCER EPIDEMIOLOGY: Understanding Causal Mechanisms and the Evidence for Implementing Interventions

In a worldwide population of 6 billion, in the year 2000, approximately 10 million cancers were diagnosed, and there were an estimated 6.2 million cancer deaths. Whereas the universality of cancer incidence and mortality is established, the burden of cancer by type or organ site is distributed unequally between developing and industrialized nations. Populations in developing countries are disproportionately affected by cancers in which infectious agents are causal. Our review of advances in cancer epidemiology underscores the complexity of pathogenic mechanisms mediated by chronic inflammation, obesity, and gene-environment interactions as in tobacco and alcohol carcinogenesis. Ultimately, the implementation of effective cancer control interventions that will serve to alleviate the cancer burden must integrate basic and applied research in the behavioral, social, biomedical, and population sciences.

Early neoplastic progression is complement independent

Infiltration of leukocytes into premalignant tissue is a common feature of many epithelial neoplasms and is thought to contribute to cancer development. However, the molecular and cellular regulatory mechanisms underlying activation of innate host responses to enhanced neoplastic cell proliferation are largely unknown. Considering the importance of the complement system in regulating inflammation during acute pathologic tissue remodeling, we examined the functional significance of complement component 3 (C3) as a regulator of inflammatory cell infiltration and activation during malignant progression by using a transgenic mouse model of multistage epithelial carcinogenesis, e.g., HPV16 mice. Whereas abundant deposition of C3 is a characteristic feature of premalignant hyperplasias and dysplasias coincident with leukocyte infiltration in neoplastic tissue, genetic elimination of C3 neither affects inflammatory cell recruitment toward neoplastic skin nor impacts responding pathways downstream of inflammatory cell activation, e.g., keratinocyte hyperproliferation or angiogenesis. Taken together, these data suggest that complement-independent pathways are critical for leukocyte recruitment into neoplastic tissue and leukocyte-mediated potentiation of tumorigenesis.

Cellular immunotherapy: antigen recognition is just the beginning

Advances in molecular and cellular biology have illustrated both the flexibility and complexity involved in host immune responses. Understanding this response is vital to the further development of therapeutic strategies that involve manipulation of the cellular immune response to target tumors. Mobilized, tumor antigen-specific T cells, the core for most immunotherapeutic strategies, are highly regulated, and capable of a wide spectrum of functional responses. Due to differences in murine and human immunity, broad-scale immune monitoring, particularly high-throughput ex vivo analysis of human immune responses, promises to determine what comprises an effective immunotherapy. Such understanding will lead to more sophisticated clinical trials, earlier determination of efficacy and individualized protocols.

Tumor necrosis factor alpha promotes invasiveness of cholangiocarcinoma cells via its receptor, TNFR2

We studied the effect of TNF-alpha stimulation on a cholangiocarcinoma cell line, CCKS1. CCKS1 expressed only one type TNF receptor, TNFR2. Treatment of CCKS1 with TNF-alpha substantially activated NFkappaB, MAPK and Akt signalings which in turn activated matrix metalloproteinase-9 (MMP-9) secretion and in vitro invasiveness of CCKS1. Pretreatment of cells with anti-TNFR2 neutralizing antibody inhibited the TNF-alpha-dependent signaling and MMP-9 secretion and subsequently blocked invasion in vitro. Moreover, an inhibitor for matrix metalloproteinase, Galardin, suppressed the invasion in a dose-dependent manner. Similarly, pharmacological inhibition of signaling clearly suppressed the TNF-alpha dependent MMP-9 secretion. These results strongly suggest that TNF-alpha-TNFR2 signaling plays an important role to convert the cholangiocarcinoma cells to be more aggressive one.

Mycobacterium tuberculosis infection and FHIT gene alterations in lung cancer

Although it is fairly well accepted that pulmonary tuberculosis is a major risk factor of lung cancer, the exact molecular mechanisms involved in its tumorigenesis are unclear. For this purpose, we have examined the relationship between Mycobacterium tuberculosis (M-TB) infection and FHIT gene alteration in lung cancer. Tumors with M-TB infection had a slightly higher abnormal FHIT protein expression compared with tumors without M-TB infection, although not statistically significant (Fisher's exact test, P=0.248). LOH affecting at least one locus of the FHIT gene was significantly more frequent in lung cancer patients with M-TB infection than in patients without M-TB infection whether assessment by univariate testing methods or logistic regression modeling analysis (Fisher's exact test P=0.025, logistic regression analysis P=0.012). These results indicate that M-TB infection is associated with FHIT gene LOH in lung cancer.

Sequence variants in Toll-like receptor gene cluster (TLR6-TLR1-TLR10) and prostate cancer risk

BACKGROUND

Chronic inflammation plays an important role in several human cancers and may be involved in the etiology of prostate cancer. Toll-like receptors (TLRs) are important in the innate immune response to pathogens and in cross-talk between innate immunity and adaptive immunity. Our previous finding of an association of TLR4 gene sequence variants and prostate cancer risk provides evidence for a role of TLRs in prostate cancer. In this study, we investigated whether sequence variants in the TLR6-TLR1-TLR10 gene cluster, residing within a 54-kb region on 4p14, were associated with prostate cancer risk.

METHODS

We selected 32 single-nucleotide polymorphisms (SNPs) covering these three genes and genotyped these SNPs in 96 control subjects from the Cancer Prostate in Sweden (CAPS) population-based prostate cancer case-control study. Five distinct haplotype blocks were inferred at this region, and we identified 17 haplotype-tagging SNPs (htSNPs) that could uniquely describe >95% of the haplotypes. These 17 htSNPs were then genotyped in the entire CAPS study population (1383 case subjects and 780 control subjects). Odds ratios of prostate cancer for the carriers of a variant allele versus those with the wild-type allele were estimated using unconditional logistic regression.

RESULTS

The allele frequencies of 11 of the 17 SNPs were statistically significantly different between case and control subjects (P = .04-.001), with odds ratios for variant allele carriers (homozygous or heterozygous) compared with wild-type allele carriers ranging from 1.20 (95% confidence interval [CI] = 1.00 to 1.43) to 1.38 (95% CI = 1.12 to 1.70). Phylogenetic tree analyses of common haplotypes identified a clade of two evolutionarily related haplotypes that are statistically significantly associated with prostate cancer risk. These two haplotypes contain all the risk alleles of these 11 associated SNPs.

CONCLUSION

The observed multiple associated SNPs at the TLR6-TLR1-TLR10 gene cluster were dependent and suggest the presence of a founder prostate cancer risk variant on this haplotype background. The TLR6-TLR1-TLR10 gene cluster may play a role in prostate cancer risk, although further functional studies are needed to pinpoint the disease-associated variants in this gene cluster.

Gelatinase-mediated migration and invasion of cancer cells

The matrix metalloproteinases(MMP)-2 and -9, also known as the gelatinases have been long recognized as major contributors to the proteolytic degradation of extracellular matrix during tumor invasion. In the recent years, a plethora of non-matrix proteins have also been identified as gelatinase substrates thus significantly broadening our understanding of these enzymes as proteolytic executors and regulators in various physiological and pathological states including embryonic growth and development, angiogenesis and tumor progression, inflammation, infective diseases, degenerative diseases of the brain and vascular diseases. Although the effect of broad-spectrum inhibitors of MMPs in the treatment of cancer has been disappointing in clinical trials, novel mechanisms of gelatinase inhibition have been now identified. Inhibition of the association of the gelatinases with cell-surface integrins appears to offer highly specific means to target these enzymes without inhibiting their catalytic activity in multiple cell types including endothelial cells, tumor cells and leukocytes. Here, we review the multiple functions of the gelatinases in cancer, and especially their role in the tumor cell migration and invasion.

Assessment of dendritic cell number and radiosensitivity in laryngeal tumours

OBJECTIVES

Radiotherapy is one of the principal treatment modalities for many types of head and neck tumour; what effects the dendritic cell (DC) population may have on treatment outcome have not been critically evaluated in laryngeal cancer.

DESIGN

Retrospective, case-controlled study using immunohistochemistry to investigate the presence of S-100 positive DC in pre-treatment, archival biopsy tissue of early stage laryngeal cancers.

SETTING

Patients with laryngeal cancer treated with radiotherapy in Head and Neck Departments in England.

PARTICIPANTS

Patients diagnosed with early stage laryngeal cancer, treated with single modality radiotherapy with curative intent. Radioresistant tumours (n = 22), defined as recurrent tumours within 12 months of therapy. Radiosensitive tumours (n = 22), defined as no recurrence with a minimum follow-up of 36 months.

MAIN OUTCOME MEASURES

Density of S-100 staining DC on three x200 magnified microscopic fields.

RESULTS

DC were present in approximately equal numbers in both radioresistant and radiosensitive laryngeal tumour pre-treatment biopsies and therefore density did not correlate with radiotherapy treatment outcome (P = 0.420).

CONCLUSION

There is no intrinsic deficiency in DC number in radioresistant laryngeal tumours meaning that such tumours could potentially benefit from vaccination strategies that enhance the specific anti-tumour immune response.

C-reactive protein in the prediction of cardiovascular and overall mortality in middle-aged men: a population-based cohort study

AIMS

Cut-offs for C-reactive protein concentrations have been recommended for risk stratification, but little is known about how these cut-offs predict cardiovascular risk in population-based cohorts. We therefore assessed the association of C-reactive protein levels with cardiovascular mortality in a population-based cohort of 2321 middle-aged men stratified by the presence of cardiovascular disease (CVD) at baseline.

METHODS AND RESULTS

C-reactive protein concentrations were categorized according to current recommendations (1 and 3 mg/L). During the 15 year follow-up, 77 men without CVD and 121 men with CVD at baseline died of CVD. In men without CVD at baseline (n=1476), age-adjusted cardiovascular mortality was 4.1-fold higher (95% CI 2.1-8.2) for C-reactive protein levels between 3.0 and 9.9 mg/L at baseline than for C-reactive protein levels <1.0 mg/L. In men with CVD at baseline (n=845), the corresponding age-adjusted cardiovascular mortality was 3.3-fold higher (95% CI 2.0-5.3). Adjustment for conventional CVD risk factors attenuated the risk somewhat. Further adjustment for dietary and lifestyle factors and factors related to insulin resistance did not affect the association. Classification of C-reactive protein by tertiles gave qualitatively similar results, but identified twice as many men at high risk. C-reactive protein levels also predicted overall mortality.

CONCLUSION

Currently, recommended cut-offs for C-reactive protein levels identify men at risk for cardiovascular and overall death independently of conventional and other risk factors in a population-based sample of middle-aged men with and without CVD at baseline. Lower cut-offs may better identify men at high risk for cardiovascular death, but improvement of current recommendations will require standardization of C-reactive protein assays.

Immunosuppressive networks in the tumour environment and their therapeutic relevance

It is well known that many tumours are potentially immunogenic, as corroborated by the presence of tumour-specific immune responses in vivo. Nonetheless, spontaneous clearance of established tumours by endogenous immune mechanisms is rare. Therefore, the focus of most cancer immunotherapies is to supplement essential immunogenic elements to boost tumour-specific immunity. Why then has tumour immunotherapy resulted in a generally poor clinical efficiency? The reason might lie in the increasingly documented fact that tumours develop diverse strategies that escape tumour-specific immunity.

Growth in epithelial cell proliferation and apoptosis correlates specifically to the inflammation activity of inflammatory bowel diseases: ulcerative colitis shows specific p53- and EGFR expression alterations

PURPOSE

Epithelial cell turnover related differences between ulcerative colitis, Crohn's colitis, and aspecific colitis are not known yet.

METHODS

Totally 345 formalin-fixed, paraffin-embedded biopsy specimens from 33 ulcerative colitis, 26 Crohn's colitis, 30 aspecific colitis, and 10 healthy patients were observed with the TdT-mediated dUTP nick end labeling method and proliferating cell nuclear antigen-, p53-, and epithelial growth factor receptor immunohistochemistry. Because of epithelial growth factor receptor positivity of subepithelial cells epithelial growth factor receptor and CD45, CD68, or CD83 double fluorescence immunohistochemistry were performed on 16 freshly frozen samples from 8 severely active ulcerative colitis and 8 severely active Crohn's colitis patients to describe lamina propria's mononuclear cells, respectively.

RESULTS

The epithelial growth factor receptor expression was significantly lower in each inflammatory group compared with normal (P < 0.005) and decreased significantly in mild ulcerative colitis compared with mild Crohn's colitis or aspecific colitis (P < 0.005). Numerous epithelial growth factor receptor and CD45 double-positive submucosal mononuclear cells were observed in moderate-severe inflammations. The p53-expression was significantly higher in each inflammatory group compared with normal (P < 0.05). Significant differences were found between mildly, moderately, and severely inflamed samples in ulcerative colitis (P < 0.05) compared with Crohn's colitis or aspecific colitis. Apoptotic/proliferative rates increased significantly in line with the inflammatory process (P < 0.0001/0.05), but the TdT-mediated dUTP nick end labeling and proliferating cell nuclear antigen-labeling characteristics did not show disease type specificity.

CONCLUSIONS

Based on our results, the alterations of epithelial growth factor receptor and p53 expression show ulcerative colitis specificity, whereas the rate of epithelial apoptosis and proliferation are determined by the histologic activity of the inflammation. The increased epithelial growth factor receptor expression by the lamina propria's mononuclear cells in inflammation may suggest its role as an autoantigen.

Anti-inflammatory Properties of the Novel Antitumor Agent Yondelis (Trabectedin): Inhibition of Macrophage Differentiation and Cytokine Production

Yondelis (Trabectedin) is a novel antitumor agent of marine origin extracted from the tunicate Ecteinascidia turbinata. This original compound is active against several human tumors including sarcoma and ovarian and breast adenocarcinoma, as evidenced in phase II clinical trials in advanced multitreated patients. Yondelis is a DNA minor groove binder that blocks cell cycle and interferes with inducible gene transcription in a selective manner. In this study, we investigated the immunomodulatory properties of Yondelis on leukocytes. Human blood monocytes were highly susceptible in vitro to its cytotoxic effect and underwent apoptosis at pharmacologically relevant concentrations (5 nmol/L), whereas lymphocytes were up to 5-fold less sensitive. Macrophages differentiated in vitro with macrophage colony-stimulating factor and tumor-associated macrophages (TAM), isolated from patients with ovarian cancer, were also susceptible. At subcytotoxic concentrations, Yondelis inhibited the in vitro differentiation of monocytes to macrophages. In tumor-treated patients, drug infusion caused a selective decrease of monocyte counts and of ex vivo macrophage differentiation. The in vitro production of two proinflammatory mediators, CCL2 and IL-6, was markedly reduced by Yondelis in monocytes, macrophages, TAM, and freshly isolated ovarian tumor cells. The chemokine CCL2 is the major determinant of monocyte recruitment at tumor sites, whereas IL-6 is a growth factor for ovarian tumors. In view of the protumor activity of TAM and of the strong association between chronic inflammation and cancer progression, the inhibitory effect of Yondelis on macrophage viability, differentiation, and cytokine production is likely to contribute to the antitumor activity of this agent in inflammation-associated human tumors.

Tumorigenesis: the adaptation of mammalian cells to sustained stress environment by epigenetic alterations and succeeding matched mutations

Recent studies indicate that during tumorigenic transformations, cells may generate mutations by themselves as a result of error-prone cell division with participation of error-prone polymerases and aberrant mitosis. These mechanisms may be activated in cells by continuing proliferative and survival signaling in a sustained stress environment (SSE). The paper hypothesizes that long-term exposure to this signaling epigenetically reprograms the genome of some cells and, in addition, leads to their senescence. The epigenetic reprogramming results in: (i) hypermethylation of tumor-suppressor genes involved in the onset of cell-cycle arrest, apoptosis and DNA repair; (ii) hypomethylation of proto-oncogenes associated with persistent proliferative activity; and (iii) the global demethylation of the genome and activation of DNA repeats. These epigenetic changes in the proliferating cells associate with their replicative senescence and allow the reprogrammed senescent cells to overcome the cell-cycle arrest and to activate error-prone replications. It is hypothesized that the generation of mutations in the error-prone replications of the epigenetically reprogrammed cells is not random. The mutations match epigenetic alterations in the cellular genome, namely gain of function mutations in the case of hypomethylation and loss of functions in the case of hypermethylation. In addition, continuing proliferation of the cells imposed by signaling in SSE speeds up the natural selection of the mutant cells favoring the survival of the cells with mutations that are beneficial in the environment. In this way, a stress-induced replication of the cells epigenetically reprograms their genome for quick adaptation to stressful environments providing an increased rate of mutations, epigenetic tags to beneficial mutations and quick selection process. In combination, these processes drive the origin of the transformed mammalian cells, cancer development and progression. Support from genomic, biochemical and medical studies for the proposed hypothesis, and its implementations are discussed.

A phase II study of etanercept (Enbrel), a tumor necrosis factor alpha inhibitor in patients with metastatic breast cancer

PURPOSE

Tumor necrosis factor (TNF) alpha is a key player in the tumor microenvironment and is involved in the pathogenesis of breast cancer. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-alpha and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biological activity, and therapeutic efficacy of Etanercept in metastatic breast cancer.

EXPERIMENTAL DESIGN

We initiated a Phase II, nonrandomized, open-labeled study in patients with progressive metastatic breast cancer refractory to conventional therapy (Phase I toxicity data were available in patients with rheumatoid arthritis). Etanercept was administered subcutaneously at a dose of 25 mg twice weekly until disease progression.

RESULTS

Sixteen patients were recruited [median age 53 years (range, 34 to 74)]. A total of 141.6 weeks of therapy was administered (median of 8.1 weeks). Seven patients received > or =12 weeks of therapy. The most common side effects were injection site reactions (6), fatigue (5), loss of appetite (2), nausea (1), headache (1), and dizziness (1). Brief period of disease stabilization was seen in 1 patient lasting for 16.4 weeks. Immunoreactive TNF-alpha was elevated within 24 hours of therapy and persisted until the end of treatment (days 7, 28, 56, and 84). Phytohemagglutinin stimulates the production of interleukin-6 and CCL2 in peripheral blood cells, and the ability of Etanercept to modulate this response was assessed in a cytokine release assay. A consistent decrease in interleukin-6 and CCL2 level was seen compared with pretreatment values in serial blood samples (days 1, 7, 28, 56, and 84).

CONCLUSIONS

Our study shows the safety and biological activity of Etanercept in breast cancer and provides data to assess pharmacodynamic endpoints of different schedules of Etanercept and combinations with chemotherapy or other biological therapies.

SHP-2 promoting migration and metastasis of MCF-7 with loss of E-cadherin, dephosphorylation of FAK and secretion of MMP-9 induced by IL-1beta in vivo and in vitro

Shp-2, an src homology (SH) two-containing phosphotyrosine phosphatase, appears to be involved in cytoplasmic signaling downstream of a variety of cell surface receptors. It also plays an important role in the control of cell spreading, migration, and cytoskeletal architecture. In our study, abrogation of SHP-2 catalytic activity with a'dominant-negative mutant (SHP-2C > S) displayed an increased number of focal adhesion, high expression of E-cadhenrin and phosphorylation of the focal adhesion kinase (FAK). Interestingly, the cells expressing SHP-2C > S showed reduced IL-1beta-stimulated chemotaxis compared with either mock- or SHP-2 wild type-transfected cells. We also found that SHP-2-GFP-transfected cell lines did not express E-cadherin nearly and produced high level of the matrix metalloproteinase MMP-9 in the supernatants. The loss of E-cadherin-mediated adhesion and the increase of MMP-9-induced migration had been shown to play an important role in the transition of epithelial tumors from a benign to an invasive state. These findings have raised the possibility that SHP-2 can promote the cancer cell to invasion the distant tissues. To determine whether SHP-2 promotes invasion and metastasis, we transfected MCF-7 breast cancer cell lines with SHP-2-GFP, SHP-2C > S-GFP and analyzed the effects of the SHP-2 on cell migration, invasion, and metastasis. In vitro, SHP-2-GFP-transfected cells migrated more efficiently, showed an increased invasion of Matrigel, and adhered less efficiently to monolayers of fibroblast cells. When injected into the abdominal cavity of nude mice, SHP-2-GFP-transfected cells metastasized widely to the lung, kidney, but MCF-7 with SHP-2C > S-GFP was not observed in the these organs. These results demonstrate that SHP-2 promotes invasion and metastasis of MCF-7 with the loss of E-cadherin, the dephosphorylation of FAK and the secretion of MMP-9 induced by IL-1beta.

The relationship between the systemic inflammatory response and survival in patients with transitional cell carcinoma of the urinary bladder

The relationship between tumour stage, grade, elevated C-reactive protein concentration (<10/>10 mg l⁻¹), adjuvant therapy and survival was examined in patients with biopsy proven bladder cancer (n=105). On multivariate analysis stage (HR 3.37, 95% CI 1.37–8.29, P=0.008), grade (HR 2.01, 95% CI 1.14–3.57, P=0.017) and preoperative C-reactive protein (HR 3.31, 95% CI 1.09–10.09, P=0.035) were independently associated with cancer-specific survival.

Transient inflammatory response induced by apoptotic cells is an important mediator of melanoma cell engraftment and growth

Two murine melanoma cell lines, Tm1 and Tm5, were derived from a nontumorigenic lineage of pigmented murine melanocytes, melan-a. Both Tm1 and Tm5 are invariably tumorigenic in syngeneic mice when inoculated s.c. in doses higher than 10(4) cells; 10(3) or fewer cells rarely give rise to tumors. We demonstrate that subtumorigenic inocula of Tm1 or Tm5 cells (10(3)) as well as of a known murine melanoma cell line (B16F10) develop as vigorously growing tumor grafts only when coinoculated with apoptotic, but not necrotic cells. The presence of apoptotic cells correlates with a transient inflammatory infiltrate, composed mainly of neutrophils and macrophages. Kinin B1 receptor-deficient mice, which have impaired transmigration of neutrophils to inflamed tissues, had significant growth inhibition of subtumorigenic doses of melanoma cells coinjected with apoptotic cells. Using the same model, tumor take in athymic mice was similar to that seen in wild-type mice, suggesting that a T cell-dependent inflammatory response is not necessary to promote the survival and growth of subtumorigenic doses of melanoma cells. Taken together, our results describe how tumor engraftment and growth can be profoundly affected by microenvironmental alterations in response to the presence of apoptotic cells. Disrupting the delicate balance between apoptotic cells and leukocyte infiltration may provide potentially important insights for understanding and interfering with tumor cell viability during treatment with either gamma-radiation or apoptosis-inducing drugs.

The emperor wears no clothes in the field of carcinogen risk assessment: ignored concepts in cancer risk assessment

The following is a position paper challenging the paradigm that 'carcinogen = mutagen', and that the current rodent bioassay to predict risks to human cancers is relevant and useful. Specifically, we review current observations concerning carcinogenesis that might lead to another approach for assessing the identification of human carcinogenic hazards and the risk assessment that chemicals might pose. We give a brief review of the multistage and multimechanism process of cancer in a tissue that involves not only genotoxic but also epigenetic events, and the importance of stem and progenitor cells in the development of cancer. We focus on the often ignored 'epigenetic' effects of carcinogens and the role of cell communication systems in epigenetically altering gene expression that leads to an imbalance of cell proliferation, differentiation and apoptosis in a tissue that can contribute to the cancer process. To draw attention to the fact that the current paradigm and policy to test toxic chemicals is often misleading and incorrect, we discuss how oxidative stress, in spite of the DNA damaging data, most probably contributes to cancer at the epigenetic level. Additionally, we briefly review how this mutagenic concept has greatly diverted attention away from doing research on the lower molecular weight, non-genotoxic, polycyclic aromatic hydrocarbons (PAHs), and how these low molecular weight PAHs are etiologically more relevant to the disease potential of environmental mixtures such as cigarette smoke.

Inflammation as a tumor promoter in cancer induction

Opposing effects of inflammation on cancer have been described. Acute inflammation usually counteracts cancer development, while chronic inflammation promotes cancer development. Just as inactivation of the p53 pathway may be universal in the neoplasia, the activation of the NFkappaB pathway may, conversely, be frequent in carcinogenesis, and a requirement for inflammation and promotion. TNF, a key pro-inflammatory cytokine when binding to TNF receptor 1 (TNFR1), may cause survival or apoptosis, dependent on biochemical modifications that determine the type of complex formed; one complex causes NFkappaB activation and gives a cell survival signal (pro-oncogenic), while the other (modified) complex recruits caspases and causes apoptosis (anti-oncogenic). Fas-ligand (FasL)-Fas interaction can also result in opposing effects on carcinogenesis due to similar mechanisms. While IL-6 counteracts apoptosis and can promote cancer development, interferons can increase DNA repair and stabilize p53, thereby be anti-oncogenic.

Decoy receptor 3 increases monocyte adhesion to endothelial cells via NF-kappa B-dependent up-regulation of intercellular adhesion molecule-1, VCAM-1, and IL-8 expression

Decoy receptor 3 (DcR3), a soluble receptor for FasL, LIGHT and TL1A, is highly expressed in cancer cells. We show that pretreatment of HUVECs with DcR3 enhances the adhesion of THP-1 and U937 cells and primary monocytes. A similar stimulatory effect of DcR3 on THP-1 adhesion was also observed in human microvascular endothelial cells (HMVECs). Flow cytometry and ELISA showed that DcR3-treated HUVECs exhibited significant increases in ICAM-1 and VCAM-1 expression. We also demonstrate the ability of DcR3 to stimulate the secretion of IL-8 by HUVECs. RT-PCR and reporter assays revealed that the expression of adhesion molecules and IL-8 are regulated at the level of gene transcription. Experiments with pyrrolidine dithiocarbamate indicated the involvement of an NF-kappaB signaling pathway. DcR3 was found to induce IkappaB kinase activation, IkappaB degradation, p65 nuclear translocation, and NF-kappaB DNA-binding activity. The enhancement by DcR3 of cell adhesion to HUVECs was not mimicked by the TL1A-Ab, which has been shown in our previous work to be a neutralizing Ab against TL1A, thereby inducing HUVECs angiogenesis. Moreover, DcR3-induced cell adhesion could be detected in human aortic endothelial cells (ECs) in which TL1A expression is lacking. Together, our data demonstrate that DcR3 increases monocyte adhesion to ECs via NF-kappaB activation, leading to the transcriptional up-regulation of adhesion molecules and IL-8 in ECs. This novel action appears not to be due to TL1A neutralization, but occurs through an as yet undefined target(s). This study implicates DcR3 in the relationship between inflammation and cancer development.

Role of anti-hepatitis C virus (HCV) treatment in HCV-related, low-grade, B-cell, non-Hodgkin's lymphoma: a multicenter Italian experience

PURPOSE

Hepatitis C virus (HCV) is endemic in some areas of Northwestern Europe and the United States. HCV has been shown to play a role in the development of both hepatocellular carcinoma and B-cell non-Hodgkin's lymphoma (B-NHL). The biologic mechanisms underlying the lymphomagenic activity of the virus so far are under investigation. In this study, the role of antiviral (anti-HCV) treatment in B-NHL associated with HCV infection is evaluated.

PATIENTS AND METHODS

Thirteen patients with histologically proven low-grade B-NHL characterized by an indolent course (ie, doubling time no less than 1 year, no bulky disease) and carrying HCV infection were enrolled on the study. All patients underwent antiviral treatment alone with pegilated interferon and ribavirin. Response assessment took place at 6 and 12 months.

RESULTS

Of the twelve assessable patients, seven (58%) achieved complete response and two (16%) partial hematologic response at 14.1 +/- 9.7 months (range, 2 to 24 months, median follow-up, 14 months), while two had stable disease with only one patient experiencing progression of disease. Hematologic responses (complete and partial, 75%) were highly significantly associated to clearance or decrease in serum HCV viral load following treatment (P = .005). Virologic response was more likely to be seen in HCV genotype 2 (P = .035), while hematologic response did not correlate with the viral genotype. Treatment-related toxicity did not cause discontinuation of therapy in all but two patients, one of whom, however, achieved complete response.

CONCLUSION

This experience strongly provides a role for antiviral treatment in patients affected by HCV-related, low-grade, B-cell NHL.

The RET/PTC-RAS-BRAF linear signaling cascade mediates the motile and mitogenic phenotype of thyroid cancer cells

In papillary thyroid carcinomas (PTCs), rearrangements of the RET receptor (RET/PTC) and activating mutations in the BRAF or RAS oncogenes are mutually exclusive. Here we show that the 3 proteins function along a linear oncogenic signaling cascade in which RET/PTC induces RAS-dependent BRAF activation and RAS- and BRAF-dependent ERK activation. Adoptive activation of the RET/PTC-RAS-BRAF axis induced cell proliferation and Matrigel invasion of thyroid follicular cells. Gene expression profiling revealed that the 3 oncogenes activate a common transcriptional program in thyroid cells that includes upregulation of the CXCL1 and CXCL10 chemokines, which in turn stimulate proliferation and invasion. Thus, motile and mitogenic properties are intrinsic to transformed thyroid cells and are governed by an epistatic oncogenic signaling cascade.

Nonsteroidal anti-inflammatory agents differ in their ability to suppress NF-kappaB activation, inhibition of expression of cyclooxygenase-2 and cyclin D1, and abrogation of tumor cell proliferation

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin have been shown to suppress transcription factor NF-kappaB, which controls the expression of genes such as cyclooxygenase (COX)-2 and cyclin D1, leading to inhibition of proliferation of tumor cells. There is no systematic study as to how these drugs differ in their ability to suppress NF-kappaB activation and NF-kappaB-regulated gene expression or cell proliferation. In the present study, we investigated the effect of almost a dozen different commonly used NSAIDs on tumor necrosis factor (TNF)-induced NF-kappaB activation and NF-kappaB-regulated gene products, and on cell proliferation. Dexamethasone, an anti-inflammatory steroid, was included for comparison with NSAIDs. As indicated by DNA binding, none of the drugs alone activated NF-kappaB. All compounds inhibited TNF-induced NF-kappaB activation, but with highly variable efficacy. The 50% inhibitory concentration required was 5.67, 3.49, 3.03, 1.25, 0.94, 0.60, 0.38, 0.084, 0.043, 0.027, 0.024, and 0.010 mM for aspirin, ibuprofen, sulindac, phenylbutazone, naproxen, indomethacin, diclofenac, resveratrol, curcumin, dexamethasone, celecoxib, and tamoxifen, respectively. All drugs inhibited IkappaBalpha kinase and suppressed IkappaBalpha degradation and NF-kappaB-regulated reporter gene expression. They also suppressed NF-kappaB-regulated COX-2 and cyclin D1 protein expression in a dose-dependent manner. All compounds inhibited the proliferation of tumor cells, with 50% inhibitory concentrations of 6.09, 1.12, 0.65, 0.49, 1.01, 0.19, 0.36, 0.012, 0.016, 0.047, 0.013, and 0.008 mM for aspirin, ibuprofen, sulindac, phenylbutazone, naproxen, indomethacin, diclofenac, resveratrol, curcumin, dexamethasone, celecoxib, and tamoxifen, respectively. Overall these results indicate that aspirin and ibuprofen are least potent, while resveratrol, curcumin, celecoxib, and tamoxifen are the most potent anti-inflammatory and antiproliferative agents of those we studied.

Systemic inflammatory response predicts outcome in patients undergoing resection for ductal adenocarcinoma head of pancreas

The aim of the present study was to examine the relationship between the clinicopathological status, the pre- and postoperative systemic inflammatory response and survival in patients undergoing potentially curative resection for ductal adenocarcinoma of the head of the pancreas. Patients (n=65) who underwent resection of ductal adenocarcinoma of the head of pancreas between 1993 and 2001, and had pre- and postoperative measurements of C-reactive protein, were included in the study. The majority of patients had stage III disease (International Union Against Cancer Criteria, IUCC), positive circumferential margin involvement (R₁), tumour size greater than 25 mm with perineural and lymph node invasion and died within the follow-up period. On multivariate analysis, tumour size (hazard ratio (HR) 2.10, 95% confidence interval (CI) 1.20–3.68, P=0.009), vascular invasion (HR 2.58, 95% CI 1.48–4.50, P<0.001) and postoperative C-reactive protein (HR 2.00, 95% CI 1.14–3.52, P=0.015) retained independent significance. Those patients with a postoperative C-reactive protein ⩽10 mg l⁻¹ had a median survival of 21.5 months compared with 8.4 months in those patients with a C-reactive protein >10 mg l⁻¹ (P<0.001). The results of the present study indicate that, in patients who have undergone potentially curative resection for ductal adenocarcinoma of the head of pancreas, the presence of a systemic inflammatory response predicts poor outcome.

Antitumor-active cobalt-alkyne complexes derived from acetylsalicylic acid: studies on the mode of drug action

Cobalt-alkyne complexes are drugs with remarkable cytotoxicity. From the complexes tested up to now we selected the aspirin derivative [2-acetoxy-(2-propynyl)benzoate]hexacarbonyldicobalt (Co-ASS) as the lead compound. To get more insight into the mode of action, we systematically modified the alkyne ligand and determined the cytotoxic properties of the resulting cobalt complexes. Further investigations were performed on the drug lipophilicity, the cellular uptake into MCF-7 and MDA-MB 231 breast cancer cells, the DNA-binding efficacy, and the nuclear drug content. The ability to inhibit glutathione reductase and cyclooxygenase (COX) enzymes, the binding to the estrogen receptor, and the induction of apoptotic processes were examined for selected compounds. Interestingly, the most antitumor active compounds were potent COX inhibitors (COX-1 and COX-2). The presented results indicate that cobalt-alkyne complexes of the Co-ASS type, represent a new class of organometallic cytostatics with a mode of drug action in which COX inhibition probably plays a major role.

Human CD4+ effector memory T cells persisting in the microenvironment of lung cancer xenografts are activated by local delivery of IL-12 to proliferate, produce IFN-gamma, and eradicate tumor cells

The implantation of small pieces of human primary lung tumor biopsy tissue into SCID mice results in a viable s.c. xenograft in which the tissue architecture, including tumor-associated leukocytes, tumor cells, and stromal cells, is preserved in a functional state. By monitoring changes in tumor volume, gene expression patterns, cell depletion analysis, and the use of function-blocking Abs, we previously established in this xenograft model that exogenous IL-12 mobilizes human tumor-associated leukocytes to kill tumor cells in situ by indirect mechanisms that are dependent upon IFN-gamma. In this study immunohistochemistry and FACS characterize the early cellular events in the tumor microenvironment induced by IL-12. By 5 days post-IL-12 treatment, the constitutively present human CD45(+) leukocytes have expanded and infiltrated into tumor-rich areas of the xenograft. Two weeks post-treatment, there is expansion of the human leukocytes and complete effacement of the tumor compared with tumor progression and gradual loss of most human leukocytes in control-treated xenografts. Immunohistochemical analyses reveal that the responding human leukocytes are primarily activated or memory T cells, with smaller populations of B cells, macrophages, plasma cells, and plasmacytoid dendritic cells capable of producing IFN-alpha. The predominant cell population was also characterized by FACS and was shown to have a phenotype consistent with a CD4(+) effector memory T cell. We conclude that quiescent CD4(+) effector memory T cells are present within the tumor microenvironment of human lung tumors and can be reactivated by the local and sustained release of IL-12 to proliferate and secrete IFN-gamma, leading to tumor cell eradication.

Phosphoinositide 3-kinase accelerates postoperative tumor growth by inhibiting apoptosis and enhancing resistance to chemotherapy-induced apoptosis. Novel role for an old enemy

Tumor removal remains the principal treatment modality in the management of solid tumors. The process of tumor removal may potentiate the resurgent growth of residual neoplastic tissue. Herein, we describe a novel murine model in which flank tumor cytoreduction is followed by accelerated local tumor recurrence. This model held for primary and recurrent tumors generated using a panel of human and murine (LS174T, DU145, SW480, SW640, and 3LL) cell lines and replicated accelerated tumor growth following excisional surgery. In investigating this further, epithelial cells were purified from LS174T primary and corresponding recurrent tumors for comparison. Baseline as well as tumor necrosis factor apoptosis-inducing ligand (TRAIL)-induced apoptosis were significantly reduced in recurrent tumor epithelia. Primary and recurrent tumor gene expression profiles were then compared. This identified an increase and reduction in the expression of p110gamma and p85alpha class Ia phosphoinositide 3-kinase (PI3K) subunits in recurrent tumor epithelia. These changes were further confirmed at the protein level. The targeting of PI3K ex vivo, using LY294002, restored sensitivity to TRAIL in recurrent tumor epithelia. In vivo, adjuvant LY294002 prolonged survival and significantly attenuated recurrent tumor growth by greatly enhancing apoptosis levels. Hence, PI3K plays a role in generating the antiapoptotic and chemoresistant phenotype associated with accelerated local tumor recurrence.

A Biological Network in Saccharomyces cerevisiae Prevents the Deleterious Effects of Endogenous Oxidative DNA Damage

In this study, we used Saccharomyces cerevisiae to identify a biological network that prevents the deleterious effects of endogenous reactive oxygen species. The absence of Tsa1, a key peroxiredoxin, caused increased rates of mutations, chromosomal rearrangements, and recombination. Defects in recombinational DNA double strand break repair, Rad6-mediated postreplicative repair, and DNA damage and replication checkpoints caused growth defects or lethality in the absence of Tsa1. In addition, the mutator phenotypes caused by a tsa1 mutation were significantly aggravated by defects in Ogg1, mismatch repair, or checkpoints. These results indicate that increased endogenous oxidative stress has broad effects on genome stability and is highly sensitive to the functional state of DNA repair and checkpoints. These findings may provide insight in understanding the consequences of various pathophysiological processes in regard to genomic instability.

Alterations of DNA damage-response genes ATM and ATR in pyothorax-associated lymphoma

Pyothorax-associated lymphoma (PAL) is non-Hodgkin's lymphoma that develops from chronic inflammation. Free radicals and oxidative stress generated in the inflammatory lesions could cause DNA damage and thus provide a basis for lymphomagenesis. Ataxia-telangiectasia mutated (ATM) and ATM and Rad3-related (ATR) genes are responsive genes for DNA damage, therefore potential involvement of these genes in PAL lymphomagenesis was examined in eight PAL cell lines and clinical samples from five cases. ATM mutations were detected in five of eight PAL lines. All but one of these mutations affected the phosphatidylinositol 3-kinase domain, indicating the loss-of-function mutation of ATM gene. Heterozygous mutations of ATR were found in two of eight lines; one a missense and the other a truncation mutation. ATR mutations were also detected in two of five cases in clinical samples from PAL. PAL cells with ATR mutation showed a delay or abrogation in repair for ionizing radiation (IR)-induced DNA double-strand breaks (DSBs) or ultraviolet (UV)-induced DNA single-strand breaks (SSBs), and exhibited a defect in p53 accumulation and failure in cell cycle checkpoint at G1-S phase. These findings showed that mutations of ATR gene result in failure for DNA DSB and SSB repair, suggesting the role of ATM and ATR gene mutations in PAL lymphomagenesis.

Inducible nitric oxide synthase-dependent DNA damage in mouse model of inflammatory bowel disease

Increased cancer risk occurs in inflammatory bowel disease (IBD) undergoing long-term chronic inflammation. To evaluate whether inducible nitric oxide synthase (iNOS)-dependent DNA damage plays a role in the carcinogenic process triggered by IBD, we prepared a mouse model of IBD induced by transfer of CD45RBhighCD4+ T cells lacking regulatory T cells to female severe combined immunodeficiency (SCID) mice. CD45RBhighCD4+ T cells were isolated from mouse spleen after staining with fluorescein isothiocyanate (FITC)-conjugated anti-CD45RB monoclonal antibody, followed by anti-FITC-conjugated microbeads. This IBD mouse model showed that the bodyweight increased with aging to a lesser extent than non-treated controls, and that the intestine was shortened. Pathological findings of this mouse model, which showed severe inflammation in colon tissues, were similar to IBD patients. Double immunofluorescence technique revealed that both 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) were formed mainly in epithelial cells of the IBD mouse model. 8-Nitroguanine was formed in most of 8-oxodG-immunoreactive nuclei of epithelial cells. iNOS, proliferating cell nuclear antigen and p53 protein were also expressed in the colon epithelium. These results indicate that nitrative DNA damage, as well as oxidative DNA damage, is induced in colon epithelial cells of the IBD mouse model followed by proliferation of these cells, which may contribute to colon carcinogenesis.

Liver-specific inactivation of the Nrf1 gene in adult mouse leads to nonalcoholic steatohepatitis and hepatic neoplasia

Knockout studies have shown that the transcription factor Nrf1 is essential for embryonic development. Nrf1 has been implicated to play a role in mediating activation of oxidative stress response genes through the antioxidant response element (ARE). Because of embryonic lethality in knockout mice, analysis of this function in the adult knockout mouse was not possible. We report here that mice with somatic inactivation of nrf1 in the liver developed hepatic cancer. Before cancer development, mutant livers exhibited steatosis, apoptosis, necrosis, inflammation, and fibrosis. In addition, hepatocytes lacking Nrf1 showed oxidative stress, and gene expression analysis showed decreased expression of various ARE-containing genes, and up-regulation of CYP4A genes. These results suggest that reactive oxygen species generated from CYP4A-mediated fatty acid oxidation work synergistically with diminished expression of ARE-responsive genes to cause oxidative stress in mutant hepatocytes. Thus, Nrf1 has a protective function against oxidative stress and, potentially, a function in lipid homeostasis in the liver. Because the phenotype is similar to nonalcoholic steatohepatitis, these animals may prove useful as a model for investigating molecular mechanisms of nonalcoholic steatohepatitis and liver cancer.

DNA damage and repair in Helicobacter pylori-infected gastric mucosa cells

Helicobacter pylori is a common human pathogen and its infection is believed to contribute to gastric cancer. Impaired DNA repair may fuel up cancer transformation by the accumulation of mutation and increased susceptibility to exogenous carcinogens. To evaluate the role of infection of H. pylori in DNA damage and repair we determined: (1) the level of endogenous basal, oxidative and alkylative DNA damage, and (2) the efficacy of removal of DNA damage induced by hydrogen peroxide and the antibiotic amoxicillin in the H. pylori-infected and non-infected GMCs. DNA damage and the efficacy of DNA repair were evaluated by the alkaline single cell gel electrophoresis (comet assay). Specific damage to the DNA bases were assayed with the DNA repair enzymes formamidopyrimidine-DNA glycosylase (Fpg) recognizing oxidized DNA bases and 3-methyladenine-DNA glycosylase II (AlkA) recognizing alkylated bases. The level of basal and oxidative DNA in the infected GMCs was higher than non-infected cells. H. pylori-infected GMCs displayed enhanced susceptibility to hydrogen peroxide than control cells. There was no difference between the efficacy of DNA repair in the infected and non-infected cells after treatment with hydrogen peroxide and amoxicillin. Our results indicate that H. pylori infection may be correlated with oxidative DNA damage in GMCs. Therefore, these features can be considered as a risk marker for gastric cancer associated with H. pylori infection and the comet assay may be applied to evaluate this marker.

Chemical biology of the sugar code

A high-density coding system is essential to allow cells to communicate efficiently and swiftly through complex surface interactions. All the structural requirements for forming a wide array of signals with a system of minimal size are met by oligomers of carbohydrates. These molecules surpass amino acids and nucleotides by far in information-storing capacity and serve as ligands in biorecognition processes for the transfer of information. The results of work aiming to reveal the intricate ways in which oligosaccharide determinants of cellular glycoconjugates interact with tissue lectins and thereby trigger multifarious cellular responses (e.g. in adhesion or growth regulation) are teaching amazing lessons about the range of finely tuned activities involved. The ability of enzymes to generate an enormous diversity of biochemical signals is matched by receptor proteins (lectins), which are equally elaborate. The multiformity of lectins ensures accurate signal decoding and transmission. The exquisite refinement of both sides of the protein-carbohydrate recognition system turns the structural complexity of glycans--a demanding but essentially mastered problem for analytical chemistry--into a biochemical virtue. The emerging medical importance of protein-carbohydrate recognition, for example in combating infection and the spread of tumors or in targeting drugs, also explains why this interaction system is no longer below industrial radarscopes. Our review sketches the concept of the sugar code, with a solid description of the historical background. We also place emphasis on a distinctive feature of the code, that is, the potential of a carbohydrate ligand to adopt various defined shapes, each with its own particular ligand properties (differential conformer selection). Proper consideration of the structure and shape of the ligand enables us to envision the chemical design of potent binding partners for a target (in lectin-mediated drug delivery) or ways to block lectins of medical importance (in infection, tumor spread, or inflammation).

Genetic polymorphism of the interferon-gamma gene in cervical carcinogenesis

Beyond human papillomavirus (HPV) infection, host genetic factors may contribute to cervical carcinogenesis. This study aims to test the hypothesis that CA-dinucleotide repeat polymorphism in the first intron of the interferon-gamma (IFN-gamma) gene is associated with HPV-initiated cervical carcinogenesis. A hospital-based case-control study including patients with low-grade squamous intraepithelial lesions (LSILs; n = 93), high-grade squamous intraepithelial lesions (HSILs; n = 123) and invasive carcinomas (n = 153) of the uterine cervix, as well as 1:1 age-matched controls, was conducted. The IFN-gamma genotype was determined by PCR and capillary electrophoresis with internal standards. HPV genotype was determined by consensus PCR and reverse line blot hybridization. Genotypes containing the 12 or 14 allele (12 or 14 CA repeats) were significantly more common in patients with HSILs than in controls (46% vs. 22%; OR = 3.0; 95% CI = 1.7-5.2; p < 0.0001). In contrast, genotypes containing 13 and 18 were significantly more common in controls than in patients with HSILs (76% vs. 53%; OR = 0.3; 95% CI = 0.2-0.6; p = 0.0001) or squamous cell carcinomas (74% vs. 63%; OR = 0.6; 95% CI = 0.4-1.0; p = 0.037). The frequency of the 12 and 14 genotypes increased significantly in accordance with the severity of cervical carcinogenesis (p(test for trend) = 0.0002), whereas the 13 and 18 genotypes showed the opposite trend (p(test for trend) = 0.007). Comparing IFN-gamma genotype and HPV status, 18-containing genotypes were more frequently found in HPV(+) LSILs, and 12-containing genotypes were less frequently found in HPV(+) HSILs. Compared with non-13 genotypes, 13 genotype HSILs were more frequently infected with HPV58 (70% vs. 45%) and less frequently infected with HPV18 (0% vs. 16%; p= 0.007). Genetic polymorphism of the IFN-gamma gene is associated with individual susceptibility to cervical carcinogenesis. This polymorphism correlates with HPV infection in a disease- and type-specific manner.

Up-regulation of the interferon gamma (IFN-gamma)-inducible chemokines IFN-inducible T-cell alpha chemoattractant and monokine induced by IFN-gamma and of their receptor CXC receptor 3 in human renal cell carcinoma

BACKGROUND

The antiangiogenic CXC chemokines interferon gamma (IFN-gamma)-inducible T-cell alpha chemoattractant (I-TAC) and monokine induced by IFN-gamma (Mig) are known as members of IFN-gamma-inducible antiangiogenic CXC chemokines. However, the expression of these chemokines in highly angiogenic tumors remains poorly understood. The authors examined expression of I-TAC, Mig, and their receptor, CXCR3, in tissue samples from patients with renal cell carcinoma (RCC).

METHODS

Twenty-one samples of untreated RCC and corresponding normal renal tissues were obtained from surgical specimens. The expression levels of I-TAC, Mig, and CXCR3 were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, real-time RT-PCR analysis, and Western blot analysis. Immunohistochemistry was carried out to clarify the localization of both chemokines and of CXCR3.

RESULTS

RT-PCR analysis showed strong expression levels of I-TAC, Mig, and CXCR3 in RCC tissues and very weak or undetectable expression in normal kidney tissues. Real-time RT-PCR analysis showed that expression levels of I-TAC, Mig, and CXCR3 in RCC tissues were 14.9 times greater, 30.3 times greater, and 9.9 times greater compared with the levels in the corresponding normal kidney tissues, respectively (P < 0.01). Western blot analysis showed up-regulation of I-TAC, Mig, and CXCR3 at the protein level. Immunofluorescence double stainings revealed that I-TAC coincided with pericytes and vascular smooth muscle cells (VSMCs) in tumor angiogenic vessels. Mig was detected in tumor endothelial cells (TECs) and in infiltrating leukocytes. In the corresponding normal kidney tissues, neither VSMCs nor endothelial cells showed positive stainings for these chemokines. CXCR3 was expressed in both tumor cells and infiltrating leukocytes.

CONCLUSIONS

The results revealed special feature of vascular mural cells and TECs in RCC. The up-regulated I-TAC and Mig, produced by tumor vessels, may interact with CXCR3 expressed in tumor cells, with possible pathophysiologic significance in RCC progression.

Functional integrity of nuclear factor kappaB, phosphatidylinositol 3'-kinase, and mitogen-activated protein kinase signaling allows tumor necrosis factor alpha-evoked Bcl-2 expression to provoke internal ribosome entry site-dependent translation of hypoxia-inducible factor 1alpha

Hypoxia-inducible factor (HIF)-1, a heterodimeric transcription factor composed of HIF-1alpha and HIF-1beta subunits coordinates pathophysiologic responses toward decreased oxygen availability. It is now appreciated that enhanced protein translation of HIF-1alpha under normoxia accounts for an alternative regulatory circuit to activate HIF-1 by hormones, growth factors, or cytokines such as tumor necrosis factor alpha (TNF-alpha). Here, we aimed at understanding molecular details of HIF-1alpha translation in response to TNF-alpha. In tubular LLC-PK(1) cells, activation of nuclear factor kappaB (NFkappaB) by TNF-alpha resulted in HIF-1alpha protein synthesis as determined by [(35)S]methionine pulse experiments. Protein synthesis was attenuated by blocking NFkappaB, phosphatidylinositol 3'-kinase (PI3k), and mitogen-activated protein kinase (MAPK). Use of a dicistronic reporter with the HIF-1alpha 5'-untranslated region (5'UTR) between two coding regions indicated that TNF-alpha promoted an internal ribosome entry site (IRES) rather than a cap-dependent translation. IRES-mediated translation required the functional integrity of the NFkappaB, PI3k, and MAPK signaling pathways. Although no signal cross-talk was noticed between NFkappaB, PI3k, and MAPK signaling, these pathways are needed to up-regulate the anti-apoptotic target protein Bcl-2 by TNF-alpha. Expression of Bcl-2 provoked not only IRES-dependent translation but also HIF-1alpha protein synthesis. We conclude that Bcl-2 functions as an important determinant in facilitating HIF-1alpha protein expression by TNF-alpha via an IRES-dependent translational mechanism. These observations suggest a link between Bcl-2 and HIF-1alpha expression, a situation with potential relevance to cancer biology.

Role of oxygen radicals in DNA damage and cancer incidence

The development of cancer in humans and animals is a multistep process. The complex series of cellular and molecular changes participating in cancer development are mediated by a diversity of endogenous and exogenous stimuli. One type of endogenous damage is that arising from intermediates of oxygen (dioxygen) reduction - oxygen-free radicals (OFR), which attacks not only the bases but also the deoxyribosyl backbone of DNA. Thanks to improvements in analytical techniques, a major achievement in the understanding of carcinogenesis in the past two decades has been the identification and quantification of various adducts of OFR with DNA. OFR are also known to attack other cellular components such as lipids, leaving behind reactive species that in turn can couple to DNA bases. Endogenous DNA lesions are genotoxic and induce mutations. The most extensively studied lesion is the formation of 8-OH-dG. This lesion is important because it is relatively easily formed and is mutagenic and therefore is a potential biomarker of carcinogenesis. Mutations that may arise from formation of 8-OH-dG involve GC --> TA transversions. In view of these findings, OFR are considered as an important class of carcinogens. The effect of OFR is balanced by the antioxidant action of non-enzymatic antioxidants as well as antioxidant enzymes. Non-enzymatic antioxidants involve vitamin C, vitamin E, carotenoids (CAR), selenium and others. However, under certain conditions, some antioxidants can also exhibit a pro-oxidant mechanism of action. For example, beta-carotene at high concentration and with increased partial pressure of dioxygen is known to behave as a pro-oxidant. Some concerns have also been raised over the potentially deleterious transition metal ion-mediated (iron, copper) pro-oxidant effect of vitamin C. Clinical studies mapping the effect of preventive antioxidants have shown surprisingly little or no effect on cancer incidence. The epidemiological trials together with in vitro experiments suggest that the optimal approach is to reduce endogenous and exogenous sources of oxidative stress, rather than increase intake of anti-oxidants. In this review, we highlight some major achievements in the study of DNA damage caused by OFR and the role in carcinogenesis played by oxidatively damaged DNA. The protective effect of antioxidants against free radicals is also discussed.

Synthesis and anti-inflammatory effects of novel pimarane diterpenoid analogs

Syntheses and excellent anti-inflammatory effects of a series of novel acanthoic acid analogs are reported. In particular, the mechanistic basis for their anti-inflammatory effects is also described.

Mechanisms of Disease: inflammation and the origins of cancer

Many common cancers develop as a consequence of years of chronic inflammation. Increasing evidence indicates that the inflammation may result from persistent mucosal or epithelial cell colonization by microorganisms; including hepatitis B virus and hepatitis C virus, which can cause hepatocellular cancer; human papilloma virus subtypes, which cause cervical cancer, and the bacterium Helicobacter pylori, which can cause gastric cancer. At present, the cause of other chronic inflammatory conditions associated with increased cancer risk, such as ulcerative colitis, is obscure. Particular microbial characteristics as well as the type of the inflammatory response contribute to clinical outcomes via influence on epithelial cell and immune responses. Persistent inflammation leads to increased cellular turnover, especially in the epithelium, and provides selection pressure that result in the emergence of cells that are at high risk for malignant transformation. Cytokines, chemokines, free radicals, and growth factors modulate microbial populations that colonize the host. Thus, therapeutic opportunities exist to target the causative microbe, the consequent inflammatory mediator, or epithelial cell responses. Such measures could be of value to reduce cancer risk in inflammation-associated malignancies.

SPARC and tumor growth: where the seed meets the soil?

Matricellular proteins mediate interactions between cells and their extracellular environment. This functional protein family includes several structurally unrelated members, such as SPARC, thrombospondin 1, tenascin C, and osteopontin, as well as some homologs of these proteins, such as thrombospondin 2 and tensascin X. SPARC, a prototypic matricellular protein, and its homolog hevin, have deadhesive effects on cultured cells and have been characterized as antiproliferative factors in some cellular contexts. Both proteins are produced at high levels in many types of cancers, especially by cells associated with tumor stroma and vasculature. In this Prospect article we summarize evidence for SPARC and hevin in the regulation of tumor cell growth, differentiation, and metastasis, and we propose that matricellular proteins such as these perform critical functions in desmoplastic responses of tumors that culminate in their dissemination and eventual colonization of other sites.