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Polymeric IgA increases the synthesis of macrophage migration inhibitory factor by human mesangial cells in IgA nephropathy.

BACKGROUND: It has been suggested that polymeric IgA (pIgA) or IgA immune complexes play a significant pathogenic role in IgA nephropathy (IgAN). Macrophage migration inhibitory factor (MIF) shares many activities with other pro-inflammatory cytokines. In human glomerulonephritis, including IgAN, glomerular expression of MIF is found to correlate with progressive renal injury. We hypothesized that deposition of pIgA within the kidney may lead to enhanced synthesis of MIF by mesangial cells. METHODS: In this study we examined the effect of pIgA and monomeric IgA (mIgA) from randomly selected patients with IgAN in clinical quiescence on the gene expression and protein synthesis of MIF in cultured human mesangial cells (HMC). RESULTS: Both pIgA and mIgA from IgAN patients or matched healthy controls increased MIF gene expression and protein synthesis in a dose-dependent fashion. The magnitude of MIF protein induction by pIgA (100 microg/ml) was similar to that of tumour necrosis factor-alpha (TNF-alpha) at 10 pg/ml. In all subjects, the induction of MIF was higher for pIgA when compared with mIgA (P < 0.01). Furthermore, the up-regulation of MIF synthesis by either pIgA or mIgA was significantly higher in IgAN patients than in healthy controls (P < 0.05). Similarly, pIgA and mIgA were able to induce TNF-alpha gene expression and protein synthesis in mesangial cells. Incubation of mesangial cells with neutralizing antibody to TNF-alpha reduced the MIF synthesis induced by pIgA. CONCLUSION: We demonstrate that pIgA is capable of inducing MIF and TNF-alpha production in HMC, which may play a major pathogenic role in IgAN. Induction of MIF can be partially blocked by neutralizing antibody to TNF-alpha, suggesting the possibility that up-regulation of MIF synthesis in HMC is mediated via an amplifying proinflammatory loop involving TNF-alpha.

Adult↗

Expression of macrophage migration inhibitory factor in human breast cancer: association with nodal spread.

Macrophage migration inhibitory factor (MIF) is known to exert pleiotropic functions including inhibition of macrophage migration, anchoring, and counteraction of the anti-inflammatory and immunosuppressive activity of glucocorticoids. Ninety-three primary breast cancer tissues and 64 sera of primary breast cancer patients were analyzed for the expression of MIF. The clinico-pathological significance of MIF expression was evaluated. It was found that MIF was frequently over-expressed in primary breast cancer tissues. RT-PCR and western blotting analysis confirmed that wild-type MIF is expressed, and immunohistochemical analysis showed that MIF expression was localized at tumor cells as well as stromal cells, including tumor-associated macrophages. Intratumoral MIF protein concentrations detected by enzyme-linked immunosorbent assay (ELISA) varied with a median value of 1821 ng/mg protein (range: 8 - 8126 ng/mg protein), and correlated inversely with nodal involvement (P = 0.039). No significant correlation was observed with other clinico-pathological factors including tumor size, menopausal status and hormone receptors. The circulating level of MIF protein ranged up to 105.7 ng/ml (median: 17.3 ng/ml), and it was also found to correlate inversely with the number of involved nodes (P = 0.02). A comparative study with other soluble inflammatory mediators showed that intratumoral levels of MIF were significantly associated with those of interleukin-1 beta, suggesting that interactions between tumor cells and tumor-associated macrophages play an important role in the up-regulation of MIF. The multifunctional inflammatory/immune mediator MIF was frequently expressed in primary breast cancer, and its expression level was inversely associated with nodal spread. Thus, MIF seems to play a role in tumor-stroma interactions of primary breast cancers, particularly those with a phenotype of node-negative or minimal nodal spread.

Adult↗

Role of monocyte-acquired hemozoin in suppression of macrophage migration inhibitory factor in children with severe malarial anemia.

Severe malarial anemia (SMA), caused by Plasmodium falciparum infections, is one of the leading causes of childhood mortality in sub-Saharan Africa. Although the molecular determinants of SMA are largely undefined, dysregulation in host-derived inflammatory mediators influences disease severity. Macrophage migration inhibitory factor (MIF) is an important regulator of innate inflammatory responses that has recently been shown to suppress erythropoiesis and promote pathogenesis of SMA in murine models. To examine the role of MIF in the development of childhood SMA, peripheral blood MIF production was examined in Kenyan children (aged <3 years, n = 357) with P. falciparum malarial anemia. All children in the study were free from bacteremia and human immunodeficiency virus type 1. Since deposition of malarial pigment (hemozoin [Hz]) contributes to suppression of erythropoiesis, the relationship between MIF concentrations and monocytic acquisition of Hz was also examined in vivo and in vitro. Circulating MIF concentrations declined with increasing severity of anemia and significantly correlated with peripheral blood leukocyte MIF transcripts. However, MIF concentrations in peripheral blood were not significantly associated with reticulocyte production. Multivariate regression analyses, controlling for age, gender, and parasitemia, further revealed that elevated levels of pigment-containing monocytes (PCM) was associated with SMA and decreased MIF production. In addition, PCM levels were a better predictor of hemoglobin and MIF concentrations than parasite density. Additional experiments in malaria-naive individuals demonstrated that hemozoin caused both increased and decreased MIF production in cultured peripheral blood mononuclear cells (PBMC) in a donor-specific manner, independent of apoptosis. However, PBMC MIF production in children with acute malaria progressively declined with increasing anemia severity. Results presented here demonstrate that acquisition of hemozoin by monocytes is associated with suppression of peripheral blood MIF production and enhanced severity of anemia in childhood malaria.

Anemia↗

Macrophage migration inhibitory factor contributes to host defense against acute Trypanosoma cruzi infection.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is involved in the host defense against several pathogens. Here we used MIF-/- mice to determine the role of endogenous MIF in the regulation of the host immune response against Trypanosoma cruzi infection. MIF-/- mice displayed high levels of blood and tissue parasitemia, developed severe heart and skeletal muscle immunopathology, and succumbed to T. cruzi infection faster than MIF+/+ mice. The enhanced susceptibility of MIF-/- mice to T. cruzi was associated with reduced levels of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-12 (IL-12), IL-18, gamma interferon (IFN-gamma), and IL-1beta, in their sera and reduced production of IL-12, IFN-gamma, and IL-4 by spleen cells during the early phase of infection. At all time points, antigen-stimulated splenocytes from MIF+/+ and MIF-/- mice produced comparable levels of IL-10. MIF-/- mice also produced significantly less Th1-associated antigen-specific immunoglobulin G2a (IgG2a) throughout the infection, but both groups produced comparable levels of Th2-associated IgG1. Lastly, inflamed hearts from T. cruzi-infected MIF-/- mice expressed increased transcripts for IFN-gamma, but fewer for IL-12 p35, IL-12 p40, IL-23, and inducible nitric oxide synthase, compared to MIF+/+ mice. Taken together, our findings show that MIF plays a role in controlling acute T. cruzi infection.

Acute Disease↗

Filarial nematode parasites secrete a homologue of the human cytokine macrophage migration inhibitory factor.

Filarial nematode parasites establish long-term chronic infections in the context of an antiparasite immunity that is strongly biased toward a Th2 response. The mechanisms that lead to this Th2 bias toward filarial antigens are not clear, but one possibility is that the parasites produce molecules that have the capacity to proactively modify their immunological environment. Here we report that filarial parasites of humans secrete a homologue of the human proinflammatory cytokine macrophage migration inhibitory factor (MIF) that has the capability of modifying the activity of human monocytes/macrophages. A cDNA clone isolated from a Brugia malayi infective-stage larva expression library encoded a 12.5-kDa protein product (Bm-MIF) with 42% identity to human and murine MIF. MIF homologues were also found to be expressed in the related filarial species Wuchereria bancrofti and Onchocerca volvulus. Bm-mif was transcribed by adult and larval parasites, and the protein product was found in somatic extracts and in the parasite's excretory-secretory products. Immunohistocytochemistry revealed that Bm-MIF was localized to cells of the hypodermis/lateral chord, the uterine wall, and larvae developing in utero. Unexpectedly, the activities of recombinant Bm-MIF and human MIF on human monocytes/macrophages were found to be similar. When placed with monocytes/macrophages in a cell migration assay, Bm-MIF inhibited random migration. When placed away from cells, Bm-MIF induced an increase in monocyte/macrophage migration that was specifically inhibited by neutralizing anti-Bm-MIF antibodies. Bm-MIF is the first demonstration that helminth parasites produce cytokine homologues that have the potential to modify host immune responses to promote parasite survival.

Amino Acid Sequence↗

Migration-inhibitory factor gene-deficient mice are susceptible to cutaneous Leishmania major infection.

To determine the role of endogenous migration-inhibitory factor (MIF) in the development of protective immunity against cutaneous leishmaniasis, we analyzed the course of cutaneous Leishmania major infection in MIF gene-deficient mice (MIF(-/-)) and wild-type (MIF(+/+)) mice. Following cutaneous L. major infection, MIF(-/-) mice were susceptible to disease and developed significantly larger lesions and greater parasite burdens than MIF(+/+) mice. Interestingly, antigen-stimulated lymph node cells from MIF(-/-) mice produced more interleukin-4 (IL-4) and gamma interferon (IFN-gamma) than those from MIF(+/+) mice, although the differences were statistically not significant. IFN-gamma-activated resting peritoneal macrophages from MIF(-/-) mice showed impaired macrophage leishmanicidal activity and produced significantly lower levels of nitric oxide and superoxide in vitro. The macrophages from MIF(-/-) mice, however, produced much more IL-6 than macrophages from wild-type mice. These findings demonstrate that endogenous MIF plays an important role in the development of protective immunity against L. major in vivo. Furthermore, they indicate that the susceptibility of MIF(-/-) mice to L. major infection is due to impaired macrophage leishmanicidal activity rather than dysregulation of Th1 and Th2 responses.

Animals↗

Intracellular growth of Legionella pneumophila gives rise to a differentiated form dissimilar to stationary-phase forms.

When Legionella pneumophila grows in HeLa cells, it alternates between a replicative form and a morphologically distinct "cyst-like" form termed MIF (mature intracellular form). MIFs are also formed in natural amoebic hosts and to a lesser extent in macrophages, but they do not develop in vitro. Since MIFs accumulate at the end of each growth cycle, we investigated the possibility that they are in vivo equivalents of stationary-phase (SP) bacteria, which are enriched for virulence traits. By electron microscopy, MIFs appeared as short, stubby rods with an electron-dense, laminar outer membrane layer and a cytoplasm largely occupied by inclusions of poly-beta-hydroxybutyrate and laminations of internal membranes originating from the cytoplasmic membrane. These features may be responsible for the bright red appearance of MIFs by light microscopy following staining with the phenolic Giménez stain. In contrast, SP bacteria appeared as dull red rods after Giménez staining and displayed a typical gram-negative cell wall ultrastructure. Outer membranes from MIFs and SP bacteria were equivalent in terms of the content of the peptidoglycan-bound and disulfide bond cross-linked OmpS porin, although additional proteins, including Hsp60 (which acts as an invasin for HeLa cells), were detected only in preparations from MIFs. Proteomic analysis revealed differences between MIFs and SP forms; in particular, MIFs were enriched for an approximately 20-kDa protein, a potential marker of development. Compared with SP bacteria, MIFs were 10-fold more infectious by plaque assay, displayed increased resistance to rifampin (3- to 5-fold) and gentamicin (10- to 1,000-fold), resisted detergent-mediated lysis, and tolerated high pH. Finally, MIFs had a very low respiration rate, consistent with a decreased metabolic activity. Collectively, these results suggest that intracellular L. pneumophila differentiates into a cyst-like, environmentally resilient, highly infectious, post-SP form that is distinct from in vitro SP bacteria. Therefore, MIFs may represent the transmissible environmental forms associated with Legionnaires' disease.

Bacterial Proteins↗

Macrophage migration inhibitory factor plays a critical role in mediating protection against the helminth parasite Taenia crassiceps.

To determine the role of endogenous migration inhibitory factor (MIF) in regulation of immune response during murine cysticercosis caused by the helminth parasite Taenia crassiceps, we analyzed the course of T. crassiceps infection in MIF(-/-) BALB/c mice. MIF(-/-) mice were highly susceptible to T. crassiceps and developed significantly higher parasite loads compared to similarly infected MIF(+/+) mice. Throughout the course of infection, Taenia crassiceps soluble antigen-stimulated spleen cells from both MIF(+/+) and MIF(-/-) mice produced significant and comparable levels of interleukin-4 (IL-4), but those from MIF(-/-) mice produced significantly more IL-13, as well as gamma interferon (IFN-gamma), suggesting that the susceptibility of MIF(-/-) mice to T. crassiceps was not due to the lack of IFN-gamma production. Interestingly, low levels of both total and specific immunoglobulin G2a were observed in MIF(-/-) cysticercotic mice despite the high IFN-gamma levels; in addition, peritoneal macrophages obtained from T. crassiceps-infected MIF(-/-) mice at different time points failed to respond efficiently to stimulation in vitro with lipopolysaccharide plus IFN-gamma and produced significantly lower levels of IL-12, tumor necrosis factor alpha, and NO compared to those from MIF(+/+) mice. These findings demonstrate that MIF plays a critical role in mediating protection against T. crassiceps in vivo. Moreover, these findings also suggest that impaired macrophage function rather than the lack of Th1 development may be responsible for mediating susceptibility to T. crassiceps.

Animals↗

Oxygen regulation of macrophage migration inhibitory factor in human placenta.

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7-10 wk and lower levels at 11-12 wk until term. Exposure of villous explants to 3% O(2) resulted in increased MIF expression and secretion relative to standard conditions (20% O(2)). DMOG treatment under 20% O(2) increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.

Adult↗

Macrophage migration inhibitory factor is a determinant of hypoxia-induced apoptosis in colon cancer cell lines.

Hypoxia contributes to cytotoxic chemotherapy and radiation resistance and may play a role in the efficacy of antiangiogenesis cancer therapy. We have generated a series of cell lines derived from the colon adenocarcinoma models HT29 and HCT116 by exposing cells in vitro to repeated sublethal periods of profound hypoxia. These cell lines have altered sensitivity to hypoxia-induced apoptosis: those derived from HT29 are resistant, whereas those from HCT116 are more susceptible. We used cDNA selected subtractive hybridization to identify novel genes mediating sensitivity to hypoxia-induced apoptosis and isolated macrophage migration inhibitory factor (MIF) from the hypoxia-conditioned cell lines. MIF expression correlates with susceptibility of the cell lines to apoptosis. In hypoxia-resistant cells, the induction of apoptosis by hypoxia can be restored by the addition of exogenous recombinant MIF protein, suggesting that resistance may result in part from down-regulation of MIF production possibly through an autocrine loop. Inhibition of MIF using small interfering RNA in the susceptible lines conferred resistance to hypoxia-induced cell death. The relative expression of MIF in the hypoxia-conditioned cells implanted s.c. in severe combined immunodeficient mice in vivo was similar to that observed in vitro. In an analysis of 12 unrelated colon tumor cell lines, MIF expression and response to hypoxia varied widely. Cell lines in which MIF was inducible by hypoxia were more sensitive to oxaliplatin. In human colon tumor specimens analyzed by immunohistochemistry, MIF expression was similarly variable. There was no detectable expression of MIF in normal colon mucosa or adenoma but positive staining in all carcinomas tested. Taken together, these data indicate that MIF may be a determinant of hypoxia-induced apoptosis in vitro and that its variable expression in human colon cancers may indicate a functional role in vivo. We suggest that MIF expression in colorectal cancer may be a marker of susceptibility to therapies that may depend on induction of hypoxia, possibly including antiangiogenic therapy.

Apoptosis↗

De novo expression of macrophage migration inhibitory factor in atherogenesis in rabbits.

Macrophage migration inhibitory factor (MIF) has been shown to play an important role in macrophage-mediated diseases. We investigate the potential role of MIF in atherogenesis using a hypercholesterolemic rabbit model. New Zealand White rabbits fed with a 2% cholesterol diet developed hypercholesterolemia and early fatty streaks at 1 month. The lesions became advanced at 3 months and were associated with de novo MIF expression by vascular endothelial cells (VECs) and smooth muscle cells (SMCs), as demonstrated by immunohistochemistry, reverse transcriptase-polymerase chain reaction, and in situ hybridization. By contrast, there was no increase in MIF levels in rabbits fed a normal diet. In early atherogenesis, marked upregulation of MIF mRNA and protein by VECs and some intimal cells were closely associated with CD68(+) monocyte adhesion onto and subsequent migration into subendothelial space. Of significance, the accumulation of macrophages was exclusively localized to areas of strong MIF expression, which may be associated with the macrophage-rich fatty streak lesion formation. Upregulation of MIF by SMCs is transient during atherogenesis. Importantly, strong MIF expression by activated macrophages may be responsible for the development of foam cell-rich lesions. Finally, the ability of MIF to induce intercellular adhesion molecule-1 expression by VECs implicates its pathogenic role in atherogenesis. In conclusion, the present study provides the first demonstration that MIF is markedly upregulated during atherogenesis. Upregulation of MIF by VECs and SMCs may play a role in macrophage adhesion, transendothelial migration, accumulation, and, importantly, transformation into foam cells. Furthermore, strong MIF expression by macrophages may both initiate and amplify the atherogenesis process.

Animals↗

Production and release of macrophage migration inhibitory factor from human adipocytes.

BACKGROUND AND AIM OF THE STUDY: Macrophage migration inhibitory factor (MIF) has been identified as a critical mediator of inflammatory responses. Because of its potent migration inhibition activity, it regulates macrophage accumulation in tissues. We therefore analyzed whether human adipocytes produce MIF, in the search of candidate mediators of macrophage infiltration of obese adipose tissue. METHODS: Human adipose tissue samples were obtained from various depots. The precursor cells were allowed to differentiate under defined adipogenic culture conditions. MIF expression was analyzed by RT-PCR, ELISA, and immunocytochemistry. RESULTS: Human preadipocytes secreted MIF in a differentiation-dependent fashion with maximum concentrations at d 12, whereas MIF mRNA was detected in both undifferentiated and differentiated cells at relatively constant levels. Immunocytochemical analysis showed that MIF protein was present in preadipocytes and more pronounced in differentiated adipocytes. Freshly isolated mature adipocytes from sc, omental, and mammary depots released MIF at rates of up to 10,000 pg/ml.24 h. Most importantly, MIF production was positively correlated with donor body mass index. Secretion of MIF was not influenced by lipopolysaccharide, interferon-gamma, or IL-4. The rates of MIF release from sc and omental adipocytes were similar but approximately 10 times higher compared with mammary adipocytes. CONCLUSIONS: Human preadipocytes and mature adipocytes from different depots spontaneously release substantial amounts of MIF. Expression levels were positively associated with donor body mass index. Hence, MIF may be an obesity-dependent mediator of macrophage infiltration of adipose tissue.

Adipocytes↗

A switch in the cellular localization of macrophage migration inhibitory factor in the rat testis after ethane dimethane sulfonate treatment.

Macrophage migration inhibitory factor (MIF), one of the first cytokines to be discovered, has recently been localized to the Leydig cells in adult rat testes. In the following study, the response of MIF to Leydig cell ablation by the Leydig cell-specific toxin ethane dimethane sulfonate (EDS) was examined in adult male rats. Testicular MIF mRNA and protein in testicular interstitial fluid measured by ELISA and western blot were only marginally reduced by EDS treatment, in spite of the fact that the Leydig cells were completely destroyed within 7 days. Immunohistochemistry using an affinity-purified anti-mouse MIF antibody localized MIF exclusively to the Leydig cells in control testes. At 7 days post-EDS treatment, there were no MIF immunopositive Leydig cells in the interstitium, although distinct MIF immunostaining was observed in the seminiferous tubules, principally in Sertoli cells and residual cytoplasm, and some spermatogonia. A few peritubular and perivascular cells were also labelled at this time, which possibly represented mesenchymal Leydig cell precursors. At 14 and 21 days, Sertoli cell MIF immunoreactivity was observed in only a few tubule cross-sections, while some peritubular and perivascular mesenchymal cells and the re-populating immature Leydig cells were intensely labeled. At 28 days after EDS-treatment, the MIF immunostaining pattern was identical to that of untreated and control testes. The switch in the compartmentalization of MIF protein at 7 days after EDS-treatment was confirmed by western blot analysis of interstitial tissue and seminiferous tubules separated by mechanical dissection. These data establish that Leydig cell-depleted testes continue to produce MIF, and suggest the existence of a mechanism of compensatory cytokine production involving the Sertoli cells. This represents the first demonstration of a hitherto unsuspected pattern of cellular interaction between the Leydig cells and the seminiferous tubules which is consistent with an essential role for MIF in male testicular function.

Animals↗

Macrophage migration inhibitory factor induces macrophage recruitment via CC chemokine ligand 2.

Macrophage migration inhibitory factor (MIF) was originally identified for its ability to inhibit the random migration of macrophages in vitro. MIF is now recognized as an important mediator in a range of inflammatory disorders. We recently observed that the absence of MIF is associated with a reduction in leukocyte-endothelial cell interactions induced by a range of inflammatory mediators, suggesting that one mechanism whereby MIF acts during inflammatory responses is by promoting leukocyte recruitment. However, it is unknown whether MIF is capable of inducing leukocyte recruitment independently of additional inflammatory stimuli. In this study, we report that MIF is capable of inducing leukocyte adhesion and transmigration in postcapillary venules in vivo. Moreover, leukocytes recruited in response to MIF were predominantly CD68(+) cells of the monocyte/macrophage lineage. Abs against the monocyte-selective chemokine CCL2 (JE/MCP-1) and its receptor CCR2, but not CCL3 and CXCL2, significantly inhibited MIF-induced monocyte adhesion and transmigration. CCL2(-/-) mice displayed a similar reduction in MIF-induced recruitment indicating a critical role of CCL2 in the MIF-induced response. This hypothesis was supported by findings that MIF induced CCL2 release from primary microvascular endothelial cells. These data demonstrate a previously unrecognized function of this pleiotropic cytokine: induction of monocyte migration into tissues. This function may be critical to the ability of MIF to promote diseases such as atherosclerosis and rheumatoid arthritis, in which macrophages are key participants.

Animals↗

Macrophage migration inhibitory factor deficiency attenuates macrophage recruitment, glomerulonephritis, and lethality in MRL/lpr mice.

Systemic lupus erythematosus (SLE) is a serious systemic autoimmune disease of unknown etiology. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is operative in innate and adaptive immunity and important in immune-mediated diseases such as rheumatoid arthritis and atherosclerosis. The functional relevance of MIF in systemic autoimmune diseases such as SLE is unknown. Using the lupus-prone MRL/lpr mice, we aim to examine the expression and function of MIF in this murine model of systemic autoimmune disease. These experiments revealed that renal MIF expression was significantly higher in MRL/lpr mice compared with nondiseased control mice (MRL/MpJ), and MIF was also markedly up-regulated in skin lesions of MRL/lpr mice. To examine the effect of MIF on development of systemic autoimmune disease, we generated MRL/lpr mice with a targeted disruption of the MIF gene (MIF(-/-)MRL/lpr), and compared their disease manifestations to MIF(+/+)MRL/lpr littermates. MIF(-/-)MRL/lpr mice exhibited significantly prolonged survival, and reduced renal and skin manifestations of SLE. These effects occurred in the absence of major changes in T and B cell markers or alterations in autoantibody production. In contrast, renal macrophage recruitment and glomerular injury were significantly reduced in MIF(-/-)MRL/lpr mice, and this was associated with reduction in the monocyte chemokine MCP-1. Taken together, these data suggest MIF as a critical effector of organ injury in SLE.

Animals↗

Quantification of macrophage migration inhibitory factor mRNA expression in non-small cell lung cancer tissues and its clinical significance.

PURPOSE: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine derived from T cells and the pituitary gland. However, several types of solid cancers also secrete MIF, and this factor has been suggested to play an important role in carcinogenesis and the progression of malignancy. In this study, we quantified MIF mRNA expression of non-small cell lung cancer tissues and examined its relationship with clinicopathological factors. EXPERIMENTAL DESIGN: MIF mRNAs of both tumor and normal tissues were quantified by a real-time monitoring reverse-transcription PCR in 59 patients with non-small cell lung cancer. The relationship between the grade of MIF expression and clinicopathological factors such as smoking history, cell type, stage, and prognosis was examined to investigate the clinical significance of intratumoral expression of MIF. RESULTS: The mean copy number of MIF mRNA per 0.08 micro g of total mRNA in tumor tissues was 144,078.00, whereas that of normal lung tissue was 25,438.46 (P < 0.0001). The amounts of MIF proteins revealed by a Western blot analysis correlated well with those of the corresponding mRNAs. Male patients and heavy smokers showed significantly higher expression of MIF. Patients with squamous cell carcinomas showed a higher expression of MIF mRNA than other subjects. In squamous cell carcinoma patients, higher expression of MIF mRNA was significantly associated with unfavorable prognosis (P = 0.0142). CONCLUSIONS: The general intratumoral expression and close relation with smoking suggested that MIF might contribute to tumorigenesis in the lung.

Biomarkers, Tumor↗

Induction of antiproliferation and apoptosis in estrogen receptor negative MDA-231 human breast cancer cells by mifepristone and 4-hydroxytamoxifen combination therapy: a role for TGFbeta1.

Mifepristone (MIF) is an antiprogestin with potent anti-glucocorticoid and anti-androgen activity. MIF also appears to have anti-tumor activity independent of its ability to bind to nuclear receptors. In this study, we tested the ability of MIF to inhibit the growth of ER and PR negative breast cancer cells. In addition, because high-dose anti-estrogen treatment has been shown to inhibit ER and PR negative breast cancer cells, we compared the anti-proliferative activity of MIF to that of the anti-estrogen 4-hydroxytamoxifen (TAM) or combination hormonal therapy (MIF + TAM). MIF and TAM therapy induced a significant time- and dose-dependent growth inhibition and, ultimately, induced cell death in MDA-231 cells as evidenced by increased DNA fragmentation, cytochrome c release from the mitochondria, and the activation of caspase-3. The anti-proliferative activity of TAM plus MIF combination treatment was at least additive as compared to either monotherapy. The earliest indicator of TAM and MIF cytostatic and cytotoxic action on MDA-231 cells was a significant (p<0.05) induction of TGFbeta1 secretion into the growth medium within 4 h of treatment. Secreted TGFbeta1 levels at 24 and 48 h were significantly higher in the TAM plus MIF treatment group as compared to cells treated with TAM or MIF alone. TGFbeta1 neutralizing antibody or addition of mannose-6-phosphate (M6P), a reagent also used to inhibit TGFbeta1, significantly attenuated the TAM and/or MIF-induced cell growth inhibition and cell death. In summary, our results indicate that MIF used in combination with TAM can effectively kill estrogen-insensitive human breast cancer cells. Our study further implies that agents that effectively increase TGFbeta1 levels in ER negative breast cancer cells may be one treatment approach for hormone-independent breast cancers.

Apoptosis↗

[Study on the treatment of high dose mifepristone and progesterone in endometrial carcinoma].

OBJECTIVE: To investigate the effect of high dose mifepristone and high dose progesterone in the treatment of patients with endometrial carcinoma and to explore the possible mechanisms associating with them. METHODS: Thirty untreated patients diagnosed as endometrial carcinoma through dilation and curettage of the uteri were divided into 3 groups at random. Each group was given medroxyprogesterone acetate (MPA), (500 mg/day) or mifepristone (MIF), (100 mg/day) or MIF (100 mg/day) + MPA (500 mg/day) for 5 days respectively. On the sixth day, hysterectomy was performed on these patients. The endometrial cancer specimen of post-hysterectomy was compared with the one of pre-administrating. The morphologic changes of the endometrial cancer cells were observed through light microscope. Immunohistochemistry assay (SP method) was applied to determine the localization and immunoreactive intensity of proliferating cell nuclear antigen (PCNA), estrogen receptor (ER), progesterone receptor (PR), B-cell leukemia lymphoma-2 (bcl-2), bcl-2 associated X protein (bax) and CD(44v6). RESULTS: Better differentiation degree and active excretion were observed in all of the post-hysterectomy endometrial specimen. In the same time, apoptosis of carcinoma cells was observed. The most significant changes were seen in the MIF + MPA group. In the MPA group, the pre-treatment and post-treatment expression of PR (2.9 +/- 1.1, 1.6 +/- 0.8), ER (2.8 +/- 0.9, 1.4 +/- 0.9), PCNA (0.84 +/- 0.10, 0.60 +/- 0.12), bcl-2 (0.236 +/- 0.089, 0.157 +/- 0.981) and CD(44v6) (4.6 +/- 1.8, 2.5 +/- 1.9) were all decreased (all P < 0.01); the expression of bax (0.20 +/- 0.10, 0.42 +/- 0.07) was increased (P < 0.01). In the MIF group, the expression of PR (3.4 +/- 1.0, 1.9 +/- 0.8), ER (2.7 +/- 0.9, 1.2 +/- 0.7), PCNA (0.80 +/- 0.15, 0.65 +/- 0.10), bcl-2 (0.214 +/- 0.097, 0.121 +/- 0.073) were all decreased (all P < 0.01); the expression of bax (0.21 +/- 0.05, 0.44 +/- 0.09) was increased (P < 0.01); no significant change in the expression of CD(44v6) (4.2 +/- 2.0, 4.3 +/- 1.7) was seen (P > 0.05). In the MIF + MPA group, the expression of PR (3.2 +/- 1.0, 0.8 +/- 0.8), ER (2.7 +/- 0.9, 0.7 +/- 0.9), PCNA (0.81 +/- 0.09, 0.25 +/- 0.09), bcl-2 (0.225 +/- 0.091, 0.066 +/- 0.009) and CD(44v6) (4.5 +/- 1.9, 2.7 +/- 1.6) were all decreased (all P < 0.01); the expression of bax (0.22 +/- 0.06, 0.59 +/- 0.09) was increased (P < 0.01); there were significant different expression of PCNA, ER, PR, bax and bcl-2 as compared with the MIF group and the MPA group, respectively (all P < 0.01). The expression of CD(44v6) was significantly different (P < 0.01) between the MIF + MPA group, and the MIF group, but not significantly different between the MIF + MPA group and the MPA group. CONCLUSIONS: The study indicates that high dose progesterone could inhibit the growth, promote apoptosis and inhibit metastasis of endometrial carcinoma, MIF could inhibit the growth and promote apoptosis, MIF + MPA could more strongly inhibit the growth, promote apoptosis and inhibit metastasis of endometrial carcinoma than MIF or MPA, and synergistic effect was observed on the expression of PCNA, ER, PR, bax and bcl-2.

Adult↗