Macrophage migration inhibitory factor stimulated by Helicobacter pylori increases proliferation of gastric epithelial cells

Macrophage Migration Inhibitory Factor (MIF) and D-Dopachrome Tautomerase (DDT): Pathways to Tumorigenesis and Therapeutic Opportunities

Discovered as inflammatory cytokines, MIF and DDT exhibit widespread expression and have emerged as critical mediators in the response to infection, inflammation, and more recently, in cancer. In this comprehensive review, we provide details on their structures, binding partners, regulatory mechanisms, and roles in cancer. We also elaborate on their significant impact in driving tumorigenesis across various cancer types, supported by extensive in vitro, in vivo, bioinformatic, and clinical studies. To date, only a limited number of clinical trials have explored MIF as a therapeutic target in cancer patients, and DDT has not been evaluated. The ongoing pursuit of optimal strategies for targeting MIF and DDT highlights their potential as promising antitumor candidates. Dual inhibition of MIF and DDT may allow for the most effective suppression of canonical and non-canonical signaling pathways, warranting further investigations and clinical exploration.

Causal associations between Helicobacter pylori infection and pregnancy and neonatal outcomes: a two-sample Mendelian randomization study

Background

Observational studies have reported that Helicobacter pylori (H. pylori) infection is associated with a series of pregnancy and neonatal outcomes. However, the results have been inconsistent, and the causal effect is unknown.

Methods

A two-sample Mendelian randomization (MR) study was performed using summary-level statistics for anti-H. pylori IgG levels from the Avon Longitudinal Study of Parents and Children Cohort. Outcome data for pregnancy (miscarriage, preeclampsia-eclampsia, gestational diabetes mellitus, placental abruption, premature rupture of membranes, postpartum hemorrhage) and neonates (birthweight, gestational age, and preterm birth) were sourced from genome-wide association meta-analysis as well as the FinnGen and Early Growth Genetics Consortium. Causal estimates were calculated by five methods including inverse variance weighted (IVW). The heterogeneity of instrumental variables was quantified by Cochran's Q test, while sensitivity analyses were performed via MR-Egger, MR-PRESSO, and leave-one-out tests.

Results

IVW estimates suggested that genetically predicted anti-H. pylori IgG levels were significantly associated with increased risks of preeclampsia-eclampsia (odds ratio [OR] = 1.12, 95% confidence interval [CI] 1.01-1.24, P = 0.026) and premature rupture of membranes (OR = 1.17, 95% CI 1.05-1.30, P = 0.004). Similar results were obtained for preeclampsia-eclampsia from the MR-Egger method (OR = 1.32, 95% CI 1.06-1.64, P = 0.027) and for premature rupture of membranes from the weighted median method (OR = 1.22, 95% CI 1.06-1.41, P = 0.006). No significant causal effects were found for other outcomes. There was no obvious heterogeneity and horizontal pleiotropy across the MR analysis.

Conclusion

Our two-sample MR study demonstrated a causal relationship of H. pylori infection with preeclampsia-eclampsia and premature rupture of membranes. The findings confirm the epidemiological evidence on the adverse impact of H. pylori in pregnancy. Further studies are needed to elucidate the pathophysiological mechanisms and assess the effectiveness of pre-pregnancy screening and preventive eradication.

Correlation between macrophage migration inhibitory factor and autophagy in Helicobacter pylori-associated gastric carcinogenesis

The role of macrophage migration inhibitory factor (MIF) and autophagy in gastric cancer is not clear. We determined H. pylori infection status of the subjects and investigated the expression of MIF and autophagy markers (Atg5, LC3A and LC3B) in human gastric tissue at baseline. Then H. pylori eradication was done for H. pylori positive patients and MIF and Atg5 levels were investigated on each follow-up for both H. pylori-eradicated and H. pylori negative patients. Baseline tissue mRNA expression of MIF, Atg5, LC3A and LC3B was measured by real-time PCR in 453 patients (control 165, gastric dysplasia 82, and gastric cancer 206). Three hundred three patients (66.9%) had H. pylori infection at the time of enrollment. Only within H. pylori-positive group, MIF level was significantly elevated in patients with cancer than in control or dysplasia groups (P<0.05). LC3A and LC3B levels also showed significant differences within H. pylori-positive subgroups. H. pylori-positive dysplasia subgroup showed significantly lower (LC3A) (P<0.05) and higher (LC3B) mRNA levels (P<0.05) than in other subgroups. On follow-up, within H. pylori-eradicated group, Atg5 expression increased sequentially from control to dysplasia and cancer subgroups. Multiple linear regression showed autophagy markers (LC3A, LC3B, and Atg5) directly predicted MIF level (adjusted R² = 0.492, P<0.001). Serial follow-up showed longitudinal increase in Atg5 level in general, with constantly higher levels in H. pylori-eradicated group than in -negative group. Intestinal metaplasia (IM) group initially showed higher Atg5 expression than the IM-negative group. However, it was reversed between the groups eventually because of the lower rate of increase in IM group. These results suggest a role of MIF and autophagy markers and their interaction in H. pylori-associated gastric carcinogenesis.

Carcinogenic Helicobacter pylori Strains Selectively Dysregulate the In Vivo Gastric Proteome, Which May Be Associated with Stomach Cancer Progression

Helicobacter pylori is the strongest risk factor for gastric cancer. Initial interactions between H. pylori and its host originate at the microbial-gastric epithelial cell interface, and contact between H. pylori and gastric epithelium activates signaling pathways that drive oncogenesis. One microbial constituent that increases gastric cancer risk is the cag pathogenicity island, which encodes a type IV secretion system that translocates the effector protein, CagA, into host cells. We previously demonstrated that infection of Mongolian gerbils with a carcinogenic cag+H. pylori strain, 7.13, recapitulates many features of H. pylori-induced gastric cancer in humans. Therefore, we sought to define gastric proteomic changes induced by H. pylori that are critical for initiation of the gastric carcinogenic cascade. Gastric cell scrapings were harvested from H. pylori-infected and uninfected gerbils for quantitative proteomic analyses using isobaric tags for relative and absolute quantitation (iTRAQ). Quantitative proteomic analysis of samples from two biological replicate experiments quantified a total of 2764 proteins, 166 of which were significantly altered in abundance by H. pylori infection. Pathway mapping identified significantly altered inflammatory and cancer-signaling pathways that included Rab/Ras signaling proteins. Consistent with the iTRAQ results, RABEP2 and G3BP2 were significantly up-regulated in vitro, ex vivo in primary human gastric monolayers, and in vivo in gerbil gastric epithelium following infection with H. pylori strain 7.13 in a cag-dependent manner. Within human stomachs, RABEP2 and G3BP2 expression in gastric epithelium increased in parallel with the severity of premalignant and malignant lesions and was significantly elevated in intestinal metaplasia and dysplasia, as well as gastric adenocarcinoma, compared with gastritis alone. These results indicate that carcinogenic strains of H. pylori induce dramatic and specific changes within the gastric proteome in vivo and that a subset of altered proteins within pathways with oncogenic potential may facilitate the progression of gastric carcinogenesis in humans.

Macrophage migration inhibitory factor (MIF) in the development and progression of pulmonary arterial hypertension

Macrophage migration inhibitory factor (MIF) has been described as a pro-inflammatory cytokine and regulator of neuro-endocrine function. It plays an important upstream role in the inflammatory cascade by promoting the release of other inflammatory cytokines such as TNF-alpha and IL-6, ultimately triggering a chronic inflammatory immune response. As lungs can synthesize and release MIF, many studies have investigated the potential role of MIF as a biomarker in assessment of patients with pulmonary arterial hypertension (PAH) and using anti-MIFs as a new therapeutic modality for PAH.

Macrophage Migration Inhibitory Factor Induces Inflammation and Predicts Spinal Progression in Ankylosing Spondylitis

OBJECTIVE

To investigate the role of macrophage migration inhibitory factor (MIF) in the pathogenesis of ankylosing spondylitis (AS).

METHODS

Patients who met the modified New York criteria for AS were recruited for the study. Healthy volunteers, rheumatoid arthritis patients, and osteoarthritis patients were included as controls. Based on the annual rate of increase in modified Stoke AS Spine Score (mSASSS), AS patients were classified as progressors or nonprogressors. MIF levels in serum and synovial fluid were quantitated by enzyme-linked immunosorbent assay. Predictors of AS progression were evaluated using logistic regression analysis. Immunohistochemical analysis of ileal tissue was performed to identify MIF-producing cells. Flow cytometry was used to identify MIF-producing subsets, expression patterns of the MIF receptor (CD74), and MIF-induced tumor necrosis factor (TNF) production in the peripheral blood. MIF-induced mineralization of osteoblast cells (SaOS-2) was analyzed by alizarin red S staining, and Western blotting was used to quantify active β-catenin levels.

RESULTS

Baseline serum MIF levels were significantly elevated in AS patients compared to healthy controls and were found to independently predict AS progression. MIF levels were higher in the synovial fluid of AS patients, and MIF-producing macrophages and Paneth cells were enriched in their gut. MIF induced TNF production in monocytes, activated β-catenin in osteoblasts, and promoted the mineralization of osteoblasts.

CONCLUSION

Our findings indicate an unexplored pathogenic role of MIF in AS and a link between inflammation and new bone formation.

Osteopontin depletion decreases inflammation and gastric epithelial proliferation during Helicobacter pylori infection in mice

Osteopontin (OPN) is a multifunctional protein that plays a role in many physiological and pathological processes, including inflammation and tumorigenesis. Here, we investigated the involvement of OPN in Helicobacter pylori (HP)-induced gastritis using OPN knockout (KO) mice and OPN knockdown (KD) cell lines. HP-infected OPN KO mice showed significantly reduced gastritis compared with wild-type (WT) mice with decreased infiltration of macrophages and a reduction in HP-induced upregulation of IL-1β, TNF-α, and IFN-γ. HP-exposed OPN KD gastric cancer cells and macrophage-like cells showed an attenuated induction of these cytokines. We also demonstrated a reduction in the migration of monocytic and macrophage-like cells toward conditioned media harvested from HP-exposed OPN KD gastric cancer cells as well as reduced migration ability of OPN KD cells itself. In addition, HP-infected OPN KO mice showed decreased epithelial cell proliferation compared with HP-infected WT mice, in association with a reduction in MAPK pathway activation. OPN KD gastric cancer cell lines also showed lower proliferative activity and reduced MAPK activation than shRNA control cells after HP co-culture or after IL-1β and TNF-α treatment. Taken together, these results indicate that OPN exerts a considerable influence on HP-induced gastritis by modulating the production of cytokines and contributing to macrophage infiltration. Moreover, OPN-mediated activation of the MAPK pathway in gastric epithelial cells might contribute to epithelial changes following HP infection.

The role of polymorphisms of genes CXCL12/CXCR4 and MIF in the risk development IBD the Polish population

Inflammatory bowel disease (IBD) are characterized recurrent inflammation of gastrointestinal tract. The etiology and pathogenesis this disease is currently unclear, but it has become evident that immune and genetic factors are involved in this process. The aim of this study was to determine whether gene polymorphisms: MIF-173 G/C; CXCL12-801 G/A and CXCR4 C/T exon 2 position of rs2228014 is associated with susceptibility to IBD. A total of 286 patients were examined with IBD, including 152 patients with ulcerative colitis and 134 with Crohn's disease (CD) and 220 healthy subjects were recruited from the Polish population. Genotyping for polymorphisms in CXCL12/CXCR4 and MIF was performed by RFLP-PCR. Statistical significance was found for polymorphisms CXCR4, a receptor gene for CXCL12 genotypes and alleles in CD and for genotype C/T and T allele in ulcerative colitis with respect to control. This confirms the effect of CXCL12 gene. The interplay between CXCL12 and its receptor CXCR4 affects homeostasis and inflammation in the intestinal mucosa. Three-gene analysis in CD confirmed the association of genotype GGGGCT. Statistical analysis of clinical data of patients with ulcerative colitis showed significant differences in the distribution of genotype C/T and T allele for CXCR4 in the left-side colitis. Having CXCR4/CXCL12 chemokine axis polymorphisms may predispose to the development of IBD. Activation can also be their defensive reaction to the long-lasting inflammation.

Macrophage migration inhibitory factor and DJ-1 in gastric cancer: differences between high-incidence and low-incidence areas

BACKGROUND

There is a need for sensitive and specific blood-borne markers for the detection of gastric cancer. Raised serum macrophage inhibitory factor (MIF) levels have been proposed as a marker for gastric cancer diagnosis but, to date, studies have only encompassed patients from high-incidence areas.

METHODS

We have compared the serum concentration of MIF in a large cohort of UK and Japanese gastric cancer patients, together with appropriate control subjects (age and gender matched). Carcinoembryonic antigen and H. pylori IgG were also measured, as was DJ-1, a novel candidate protein biomarker identified by analysis of gastric cancer cell line secretomes.

RESULTS

Marked elevations of the serum concentration of MIF and DJ-1 were seen in Japanese patients with gastric cancer compared with Japanese controls, a trend not seen in the UK cohort. These results could not be accounted for by differences in age, disease stage or H. pylori status.

CONCLUSION

In regions of high, but not low incidence of gastric cancer, both MIF and DJ-1 have elevated serum concentrations in gastric cancer patients, compared with controls. This suggests that differing mechanisms of disease pathogenesis may be at play in high- and low-incidence regions.

Gastric cancer susceptibility in gastric cancer relatives: attributable risks of Macrophage migration inhibitory factor promoter polymorphism and Helicobacter pylori

The purpose of this study is to assess attributable effects of Macrophage migration inhibitory factor (MIF) promoter region polymorphisms and Helicobacter pylori infection to the susceptibility to gastric cancer. 296 individuals from non-cardia gastric cancer case families and 319 individuals from control families were obtained from Henan Province, China. The results showed the frequencies of MIF (-173 C/C and -794 non-CATT(5)carrier) genotypes were significantly higher in the family members of gastric cancer cases than that in the controls family (-173: OR=2.59; -794: OR=2.65), and the ORs reduced with decreasing relative degrees. Multivariate analysis showed that MIF-173 C and -794 non-CATT(5) alleles synergized with H. pylori for the risk of gastric cancer (OR=14.64). The attributable risk percent (ARP) and the population attributable risk percent (PARP) attributed to interaction of MIF-173 C/C and MIF-794 non-CATT(5)carrier were 72.3% and 4.7%, respectively. The MIF risk genotypes and H. pylori conferred a joint ARP of 93.2% to gastric cancer. In summary, Possession of -173 G→C substitution and -794 non-CATT(5)carrier in the MIF promoter region are associated with increased susceptibility to non-cardia gastric cancer. H. pylori infection increases the risks of MIF polymorphisms for susceptibility with gastric cancer.

Cell-cycle inhibition by Helicobacter pylori L-asparaginase

Helicobacter pylori (H. pylori) is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application.

The effect of Helicobacter pylori eradication on macrophage migration inhibitory factor, C-reactive protein and fetuin-a levels

OBJECTIVES

To determine the effect of Helicobacter pylori (H. pylori) eradication on blood levels of high-sensitivity C-reactive protein (hs-CRP), macrophage migration inhibitory factor and fetuin-A in patients with dyspepsia who are concurrently infected with H. pylori.

METHODS

H.pylori infection was diagnosed based on the 14C urea breath test (UBT) and histology. Lansoprazole 30 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily were given to all infected patients for 14 days; 14C UBT was then re-measured. In 30 subjects, migration inhibitory factor, fetuin-A and hs-CRP levels were examined before and after the eradication of H. pylori infection and compared to levels in 30 healthy subjects who tested negative for H. pylori infection.

RESULTS

Age and sex distribution were comparable between patients and controls. Migration inhibitory factor and hs-CRP levels were higher, and fetuin-A levels were lower, in H. pylori-infected patients (p<0.05). Following eradication of H. pylori, migration inhibitory factor and hs-CRP levels were significantly decreased, whereas fetuin-A levels were increased. However, eradication of the organism did not change lipid levels (p>0.05).

CONCLUSION

These findings suggest that H. pylori eradication reduces the levels of pro-inflammatory cytokines such as migration inhibitory factor and hs-CRP and also results in a significant increase in anti-inflammatory markers such as fetuin-A.

The effect of Helicobacter pylori eradication on macrophage migration inhibitory factor, C-reactive protein and fetuin-a levels

OBJECTIVES

To determine the effect of Helicobacter pylori (H. pylori) eradication on blood levels of high-sensitivity C-reactive protein (hs-CRP), macrophage migration inhibitory factor and fetuin-A in patients with dyspepsia who are concurrently infected with H. pylori.

METHODS

H.pylori infection was diagnosed based on the 14C urea breath test (UBT) and histology. Lansoprazole 30 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily were given to all infected patients for 14 days; 14C UBT was then re-measured. In 30 subjects, migration inhibitory factor, fetuin-A and hs-CRP levels were examined before and after the eradication of H. pylori infection and compared to levels in 30 healthy subjects who tested negative for H. pylori infection.

RESULTS

Age and sex distribution were comparable between patients and controls. Migration inhibitory factor and hs-CRP levels were higher, and fetuin-A levels were lower, in H. pylori-infected patients (p<0.05). Following eradication of H. pylori, migration inhibitory factor and hs-CRP levels were significantly decreased, whereas fetuin-A levels were increased. However, eradication of the organism did not change lipid levels (p>0.05).

CONCLUSION

These findings suggest that H. pylori eradication reduces the levels of pro-inflammatory cytokines such as migration inhibitory factor and hs-CRP and also results in a significant increase in anti-inflammatory markers such as fetuin-A.

Serum macrophage migration-inhibitory factor as a diagnostic and prognostic biomarker for gastric cancer

BACKGROUND

This study aimed to determine the potential diagnostic value of migration-inhibitory factor (MIF) for gastric cancer in patients presenting with dyspepsia and its prognostic value for gastric cancer.

METHODS

A cohort of 97 patients with histologically confirmed gastric adenocarcinoma and 222 patients with dyspepsia were recruited. Enzyme-linked immunosorbent assay was used to measure serum MIF and carcinoembryonic antigen (CEA).

RESULTS

The serum MIF concentrations were 6554.0 +/- 204.1 pg/mL and 1453.7 +/- 79.9 pg/mL, respectively, in gastric cancer patients and dyspeptic patients (P < .001). Serum MIF levels increased with the advancing gastric pathologies (P < .001). With the cutoff value of 3230 pg/mL, serum MIF had sensitivity, specificity, and accuracy of 83.5%, 92.3%, and 89.7%, respectively, in diagnosing gastric cancer, whereas the rates were 60.8%, 83.3%, and 76.5%, respectively, for serum CEA. Gastric cancer patients with serum MIF levels above 6600 pg/mL had a lower 5-year survival rate than those with serum MIF level below that level (P = .012). Higher serum CEA levels were also associated with poor survival. The prediction for 5-year survival was even better (P = .0001), using a combination of serum MIF and CEA.

CONCLUSIONS

Serum MIF level, which correlates with gastric MIF expression, is a better molecular marker than CEA in diagnosing gastric cancer in patients presenting with dyspepsia. A combination of serum MIF and CEA predicts 5-year survival better than the individual test.

CD74 in antigen presentation, inflammation, and cancers of the gastrointestinal tract

CD74 is a protein whose initial role in antigen presentation was recognized two decades ago. Recent studies have revealed that it has additional functions as a receptor for macrophage migration inhibitory factor and as a receptor for an important human pathogen, Helicobacter pylori (H pylori). The role of CD74 as a receptor is important because after binding of migration inhibitory factor or H pylori, NF-κB and Erk1/2 activation occurs, along with the induction of proinflammatory cytokine secretion. This review provides an up-to-date account of the functions of CD74 and how it might be involved in inflammation and cancer within the gastrointestinal tract.

Macrophage migration inhibitory factor (MIF), enzymatic activity and the inflammatory response

Macrophage migration inhibitory factor represents a key cytokine in human diseases. It plays an important role in both innate and acquired immunity and has been shown to be a key mediator of inflammatory diseases. More recently MIF has been implicated in cancer pathogenesis. Over the decades its structure and functions have been elucidated and this has led to it being further classified as a hormone and an enzyme. It has isomerase enzymatic activity and increasing evidence implicates this activity in inflammatory disease. Consequently, there is increasing interest in developing small molecular weight inhibitors which could target this novel enzymatic activity in disease. (c) 2009 International Union of Biochemistry and Molecular Biology, Inc.

Expression of inflammatory mediators in the otitis media induced by Helicobacter pylori antigen in mice

Helicobacter pylori is a Gram-negative bacterium that is recognized as one of the key factors in gastric diseases such as gastritis, peptic ulcer and gastric cancer. Recent studies have shown relationships between H. pylori and extra-digestive diseases, and the presence of H. pylori in the middle ear and upper respiratory tract has been reported. However, the role of H. pylori in middle ear disease remains unclear. The present study demonstrated that H. pylori whole-cell protein directly induces macrophage migration inhibitory factor, macrophage inflammatory protein 2, interleukin 1 beta and tumor necrosis factor alpha in middle ear epithelium in mice, and severe proliferation of inflammatory cells was observed in middle ear cavity inoculated with H. pylori whole-cell protein. In addition, trans-tympanic injection of macrophage migration inhibitory factor up-regulated expression of macrophage inflammatory protein 2 in the middle ear. These findings indicate that H. pylori infection causes immunological inflammation in middle ear epithelium, and H. pylori may play a significant role in otitis media.

Pre-eclampsia is associated with Helicobacter pylori seropositivity in Italy

OBJECTIVES

Pre-eclampsia (PE) is characterized by an excess of inflammation and endothelial dysfunction. Helicobacter pylori (H. pylori) causes chronic inflammatory changes and endothelial damage. We investigated the prevalence of seropositivity for IgG against H. pylori and cytotoxin-associated antigen A (CagA) in PE patients and the presence of H. pylori DNA in their placentas.

METHODS

We tested 47 pregnant women with PE and 47 with uneventful pregnancies for serum antibodies against H. pylori (enzyme immunoassays) and CagA protein (immunoblot assays). In 20 of them (10 normal and 10 PE) we assessed the presence, in the placenta, of H. pylori DNA by means of nested polymerase chain reaction (PCR). The odds ratios (OR) and 95% confidence intervals (CI), adjusted for parity, were calculated using logistic regression analysis to assess the risk of PE associated with H. pylori infection.

RESULTS

Helicobacter pylori seropositivity frequency was higher in mothers with PE (51.1%) compared to women with uneventful pregnancy (31.9%) (OR, 2.668; 95% CI, 1.084-6.566; P = 0.033). The difference was even greater for CagA seropositivity (80.9 and 14.9%, respectively) (OR, 26.035; 95% CI, 8.193-82.729; P < 0.001). All placentas were negative for H. pylori DNA.

CONCLUSIONS

Helicobacter pylori, and especially strains carrying the CagA gene, may contribute to the inflammatory mechanisms involved in the pathogenesis of PE.

Haemaphysalis longicornis: Molecular characterization of a homologue of the macrophage migration inhibitory factor from the partially fed ticks

The macrophage migration inhibitory factor (MIF) has been identified from some vertebrates and invertebrates. MIF is related to inflammation, tumor growth, and angiogenesis in vertebrates. Here, we report the molecular characterization of a homologue of MIF from partially fed Haemaphysalis longicornis. The sequence analysis of the H. longicornis MIF (HlMIF) indicated that its deduced amino acid sequence has an identity of 77% with the MIF of the tick Amblyomma americanum. Western blot analysis using the anti-His-HlMIF antibody showed that HlMIF was up-regulated during blood feeding. Immunohistochemistry showed that the endogenous HlMIF in partially fed ticks was localized to the midgut and epidermal cells. Moreover, the functional assay revealed that the GST-HlMIF inhibited the migration of human monocytes. In conclusion, we consider that HlMIF may facilitate blood feeding by inhibiting host macrophage migration to the feeding lesion or may participate in the proliferation and differentiation of cells in the tick body.

Helicobacter pylori CagA-dependent macrophage migration inhibitory factor produced by gastric epithelial cells binds to CD74 and stimulates procarcinogenic events

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that has recently been implicated in carcinogenesis. Helicobacter pylori, which is closely linked to gastric cancer, induces the gastric epithelium to produce proinflammatory cytokines, including MIF. MIF can bind to CD74, which we have previously shown to be highly expressed on the surface of gastric epithelial cells (GEC) during H. pylori infection. In this study, we sought to investigate the role of the H. pylori-induced MIF on epithelial proliferation and procarcinogenic events. Upon establishing a role for the H. pylori CagA virulence factor in MIF production, MIF binding to CD74 on GEC was confirmed. rMIF and H. pylori were shown to increase GEC proliferation, which was decreased when cagA- strains were used and when CD74 was blocked by mAbs. Apoptosis was also decreased by MIF, but increased by cagA- strains that induced much lower amounts of MIF than the wild-type bacteria. Furthermore, MIF binding to CD74 was also shown to decrease p53 phosphorylation and up-regulate Bcl-2 expression. This data describes a novel system in which an H. pylori virulence factor contributes to the production of a host factor that in turn up-regulates procarcinogenic events by the gastric epithelium.

Increased epithelial and serum expression of macrophage migration inhibitory factor (MIF) in gastric cancer: potential role of MIF in gastric carcinogenesis

AIMS

Macrophage migration inhibitory factor (MIF) is implicated in tumorigenesis. This study was conducted to determine whether MIF expression is associated with gastric pathology and whether MIF expression is increased in malignant gastric cells in vitro.

MATERIALS AND METHODS

Patients with a normal gastric mucosa, Helicobacter pylori infected gastritis, intestinal metaplasia, and gastric adenocarcinoma were included. Immunohistochemistry and enzyme linked immunosorbent assay (ELISA) were used to determine MIF expression in gastric epithelial cells and MIF levels in serum, respectively. Five gastric cancer cell lines (AGS, MKN-45, MKN-28, MGC-803, and SGC-7901) and one non-malignant gastric cell line (GES-1) were cultured for 24 hours. MIF protein in the supernatant and MIF mRNA in cultured cells were measured by ELISA and reverse transcription-polymerase chain reaction, respectively.

RESULTS

The percentage of MIF expressing epithelial cells was low in normal mucosa (12%) but substantially higher in gastritis (52%), intestinal metaplasia (66%), and gastric cancer (96%) (p<0.001, ANOVA). Serum MIF levels were low in patients with a normal mucosa (576 (82) pg/ml) but higher in patients with gastritis (2100 (349) pg/ml), intestinal metaplasia (4498 (253) pg/ml), and gastric cancer (9737 (1249) pg/ml) (p<0.001, ANOVA). There was a correlation between epithelial MIF expression and serum MIF levels (r = 0.776, p<0.001). In vitro, expression of MIF protein and mRNA was increased in malignant cells compared with non-malignant cells.

CONCLUSIONS

Epithelial and serum MIF expression was progressively increased in H pylori induced gastritis, intestinal metaplasia, and gastric cancer, suggesting that MIF is involved in gastric carcinogenesis and may be a valuable biomarker for the early detection of gastric cancer.