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Background: Docetaxel improves symptoms and survival in metastatic castration-resistant prostate cancer (CRPC). However, ∼50% of patients are chemoresistant. This study examined whether changes in cytokine levels predict for docetaxel resistance in vitro and in a clinical cohort., Methods: PC3 cells or their docetaxel-resistant subline (PC3Rx) were co-cultured with U937 monocytes, with and without docetaxel treatment, and cytokine levels were measured. The circulating levels of 28 cytokines were measured pre-/post cycle 1 of docetaxel from 55 men with CRPC, and compared with prostate-specific antigen (PSA) response., Results: PC3Rx-U937 co-culture expressed more cytokines, chiefly markers of alternative macrophage differentiation, compared with PC3-U937 co-culture. Docetaxel treatment enhanced cytokine production by PC3Rx-U937 co-culture, while reducing cytokine levels in PC3-U937. In patients, changes in the levels of seven circulating cytokines (macrophage inhibitory cytokine 1 (MIC1), interleukin (IL)-1ra, IL-1β, IL-4, IL-6, IL-12 and IFNγ) after cycle 1 of docetaxel were associated with progressive disease (all P<0.05). The combination of changes in MIC1, IL-4 and IL-6 most strongly predicted PSA response (P=0.002)., Conclusions: In vitro studies suggest docetaxel resistance is mediated, at least in part, by cytokines induced by the interaction between the docetaxel-resistant tumour cells and macrophages. Early changes in circulating cytokine levels were associated with docetaxel resistance in CRPC patients. When considered together, these data suggest a significant role for the inflammatory response and macrophages in the development of docetaxel resistance in CRPC.

Objectives: To measure maternal serum and amniotic fluid levels of macrophage inhibitory cytokine-1 (MIC-1) in Down syndrome and normal pregnancies, assessing the utility of MIC-1 as a prenatal marker of Down syndrome., Methods: Stored serum from 64 Down syndrome and 399 control pregnancies, collected at 8 to 17 weeks of pregnancy, and stored amniotic fluid from 17 Down syndrome and 53 controls, collected at 15 to 19 weeks of pregnancy, were retrieved for analysis. MIC-1 was measured using an established in-house ELISA, blinded to sample type., Results: In maternal serum, MIC-1 levels are not altered in Down syndrome in either the first or second trimester. Levels, expressed as median (95% CI) multiples of the median (MoM), in the Down syndrome cases and controls were 1.07 (0.9-1.1) MoM and 1.0 (0.95-1.03) MoM respectively. In amniotic fluid, MIC-1 levels were significantly decreased compared to controls, 0.52 (0.44-0.64) MoM versus 1.0 (0.85-1.08) MoM (p < 0.0001)., Conclusion: MIC-1 is decreased in amniotic fluid but not in maternal serum in Down syndrome pregnancies. MIC-1 will not be useful as a prenatal marker of Down syndrome., (Copyright 2004 John Wiley & Sons, Ltd.)

Macrophage inhibitory cytokine-1 (MIC-1), a divergent member of transforming growth factor-beta superfamily, has been recently shown to be produced by the human placenta with detectable levels in maternal serum. In this study, using immunohistochemistry, we have localized MIC-1 in placenta, decidua and foetal membranes across pregnancy and, using an enzyme-linked immunoassay, measured MIC-1 in maternal serum in normal pregnancy, in association with labour and pre-eclampsia. In the placenta MIC-1 was principally localized to the syncytiotrophoblast while in the foetal membranes MIC-1 was present in the amniotic epithelium, chorionic trophoblasts and adherent decidual cells. There were no differences in MIC-1 staining distribution or intensity in the placentae between women in labour and not in labour, or between healthy and pre-eclamptic pregnancies. MIC-1 staining in the foetal membranes was slightly stronger after a labour and delivery compared to those delivered by elective Caesarean section. MIC-1 levels in the maternal serum increased with advancing gestation but there were no significant differences in maternal serum levels associated with either labour or pre-eclampsia.These observations would be consistent with MIC-1 having roles at the maternal-foetal interface, perhaps in the establishment and/or maintenance of pregnancy. Our data argue against MIC-1 having a significant role in the regulation of labour or in the pathophysiology of pre-eclampsia.

Macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the TGF-beta superfamily. There are at least two known alleles of MIC-1 that are due to a G-->C point substitution at position 6 of the mature protein, which alters a histidine to an aspartic acid (MIC-1 H and MIC-1 D). We have determined the phenotype of MIC-1 circulating in serum by exploiting the differences in the affinity of the two monoclonal antibodies to the H and D alleles of MIC-1. A PCR-RFLP-based method for genotyping MIC-1 is also described. We validate these two assays using DNA sequencing of 19 subjects as the standard. We then used the validated assay to determine the frequency of the two MIC-1 alleles in a population of 261 adult blood donors. Inter-assay and sequencing concordance was 100%. The frequency of the three common MIC-1 genotypes was homozygous (HH), 54%; heterozygous (HD), 39%; and homozygous (DD), 7%. This novel antibody-based assay confidently determines the genotype of MIC-1. It offers the advantages of an ELISA-ease of automation, high-volume throughput of samples, and ease of use in a routine, clinical laboratory.

We and others have recently cloned a new member of the transforming growth factor-beta superfamily, growth differentiation factor-15/ macrophage inhibitory cytokine-1 (GDF-15/MIC-1). Using in situ hybridization and immunohistochemistry, we determined the distribution of GDF-15/MIC-1 mRNA and protein in the perinatal and cryolesioned adult rat brain. The choroid plexus epithelium of all ventricles represents the site of strongest and almost exclusive mRNA expression in the normal perinatal and adult brain. The newborn rat brain reveals GDF-15/MIC-1 immunoreactivity (ir) in ependymal cells lining the ventricles, in the striatal subventricular zone, and in populations of nonneural cells of the thalamic/hippocampal lamina affixa, in addition to that in the choroid plexus. Unilateral cryogenic cortical lesioning induced a significant increase of GDF-15/MIC-1 mRNA expression and ir at the lesion site and expression in presumed neurons within the dorsal thalamic area. At the lesion site, GDF-15/MIC-1-producing cells showed immuncytochemical features of neurons, macrophages, and activated microglial cells. Fluorescent microscopy revealed both intra- and extracellular GDF-15/MIC-1 ir. Up-regulation of GDF-15/MIC-1 in activated macrophages (Mstraight phi) is also supported by RT-PCR, ICC, and Western blot experiments showing pronounced induction of GDF-15/MIC-1 expression (mRNA and protein) in retinoic acid/phorbol ester-stimulated human M phi. Our data suggest that 1) GDF-15/MIC-1 is secreted into the cerebrospinal fluid and 2) in the newborn brain may penetrate through the ependymal lining and act on developing neurons and/or glial cells. As a constituent of cells in the lamina affixa, the protein might be involved in the regulation of mesenchyme-epithelial interactions. Finally, GDF-15/MIC-1 may also act within the antiinflammatory cytokine network activated in CNS lesions., (Copyright 2001 Wiley-Liss, Inc.)

Macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the transforming growth factor-beta (TGF-beta) superfamily. While it is synthesized in a pre-pro form, it is unique among superfamily members because it does not require its propeptide for correct folding or secretion of the mature peptide. To investigate factors that enable these propeptide independent events to occur, we constructed MIC-1/TGF-beta1 chimeras, both with and without a propeptide. All chimeras without a propeptide secreted less efficiently compared with the corresponding constructs with propeptide. Folding and secretion were most affected after replacement of the predicted major alpha-helix in the mature protein, residues 56-68. Exchanging the human propeptide in this chimera with either the murine MIC-1 or TGF-beta1 propeptide resulted in secretion of the unprocessed, monomeric chimera, suggesting a specific interaction between the human MIC-1 propeptide and mature peptide. Propeptide deletion mutants enabled identification of a region between residues 56 and 78, which is important for the interaction between the propeptide and the mature peptide. Cotransfection experiments demonstrated that the propeptide must be in cis with the mature peptide for this phenomenon to occur. These results suggest a model for TGF-beta superfamily protein folding.

Macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the transforming growth factor-beta (TGF-beta) superfamily whose increased expression is associated with macrophage activation and which is expressed highly in placenta as compared to other tissues. There are two known allelic forms of human MIC-1 due an amino acid substitution at position 6 of the mature protein. We have raised four monoclonal antibodies (MAbs) and one polyclonal antiserum to the mature protein region of human MIC-1 and have used an extensive panel of MIC-1 relatives, mutants, and chimeras to map their epitopes. None of the MAbs were able to cross-react with either the murine homologue of MIC-1 or with hTGF-beta1, and all of the MAb epitopes were conformation-dependent. A distinct cross-reactivity pattern with the various antigens was observed for each of the monoclonal and polyclonal antibodies suggesting the presence of at least five immunogenic regions on the MIC-1 surface. One of the MAbs is directed against the amino terminus of the protein and can distinguish between the two allelic forms of MIC-1. The epitopes for the other three MAbs were located near the tips of the so-called "fingers" of the protein and appeared to be partially overlapping as each involved amino acids in the region 24-37. In one case, it was possible to mutate murine MIC-1 so that it could be recognized by one of the MAbs. Finally, the use of another mutant in which Cys 77 was replaced by serine enabled confirmation of the location of the MIC-1 interchain disulfide bond.

Macrophage inhibitory cytokine-1 (MIC-1) is a recently described divergent member of the transforming growth factor-ss superfamily. MIC-1 transcription up-regulation is associated with macrophage activation, and this observation led to its cloning. Northern blots indicate that MIC-1 is also present in human placenta. A sensitive sandwich enzyme-linked immunosorbent assay for the quantification of MIC-1 was developed and used to examine the role of this cytokine in pregnancy. High levels of MIC-1 are present in the sera of pregnant women. The level rises substantially with progress of gestation. MIC-1 can also be detected, in large amounts, in amniotic fluid and placental extracts. In addition, the BeWo placental trophoblastic cell line was found to constitutively express the MIC-1 transcript and secrete large amounts of MIC-1. These findings suggest that the placental trophoblast is a major source of the MIC-1 present in maternal serum and amniotic fluid. We suggest that MIC-1 may promote fetal survival by suppressing the production of maternally derived proinflammatory cytokines within the uterus.

The methylotrophic yeast, Pichia pastoris, has been used to express both human and murine macrophage inhibitory cytokine-1 (MIC-1), a transforming growth factor beta (TGF-beta) superfamily cytokine. This is the first report of the expression of a correctly folded TGF-beta superfamily protein in a microbial organism. The protein is secreted in its correctly folded dimeric form at milligram per litre quantities, which are significantly higher than we have been able to achieve using mammalian expression systems. Purification schemes are described, and the purified protein is immunologically identical to protein produced in a mammalian expression system. Protein expression was influenced by a number of factors, most significantly by the concentration of methanol used during the induction phase. However, with very high levels of MIC-1 induction, substantial amounts of MIC-1 monomer were also secreted.

Macrophage inhibitory cytokine (MIC-1), a divergent member of the transforming growth factor-beta (TGF-beta) superfamily and activation associated cytokine, is secreted as a 28 kDa dimer. To understand its secretion, we examined its processing in MIC-1-transfected Chinese hamster ovary cells. Mature MIC-1 dimer arises post-endoplasmic reticulum (ER) by proteolytic cleavage of dimeric pro-MIC-1 precursor at a furin-like site. Unlike previously characterized TGF-beta superfamily members, MIC-1 dimers are also secreted in constructs lacking the propeptide. A clue to the function of the propeptide came from the observation that a range of proteasome inhibitors, including lactacystin and MG132, cause major increases in levels of undimerized pro-MIC-1 precursor. There was no effect of proteasome inhibitors on cells expressing mature MIC-1 without the propeptide, suggesting that the propeptide can signal misfolding of MIC-1, leading to proteasomal degradation. Deletion mutagenesis showed the N-terminal 28 amino acids of the propeptide are necessary for proteasomal degradation. This is the first demonstration, to our knowledge, of a quality control function in a propeptide domain of a secretory protein and represents an additional mechanism to ensure correct folding of proteins leaving the ER.

As part of a study to identify novel genes associated with macrophage activation, we have cloned a new member of the transforming growth factor beta (TGF-beta) superfamily designated macrophage inhibitory cytokine 1 (MIC-1). MIC-1 is synthesized as a 62-kDa intracellular protein, which, after cleavage by a furin like protease, is secreted as a 25-kDa disulfide-linked dimeric protein. Sequence analysis indicates that it does not cluster within any existing TGF-beta families, suggesting it may be the first member of a new grouping within the TGF-beta superfamily. Tissue Northern blots show that MIC-1 transcripts are only found abundantly in placenta, although smaller amounts are seen in a limited number of other adult and fetal tissues. MIC-1 is not expressed in resting macrophages but is induced by a number of different activation agents, including phorbol myristate acetate, interleukin 1, tumor necrosis factor alpha, and macrophage colony-stimulating factor but not by lipopolysaccharide or interferon-gamma. We have hypothesized that it may be an autocrine inhibitor of macrophage activation but its major biological role is still uncertain.

Macrophages play a key role in both normal and pathological processes involving immune and inflammatory responses, to a large extent through their capacity to secrete a wide range of biologically active molecules. To identify some of these as yet not characterized molecules, we have used a subtraction cloning approach designed to identify genes expressed in association with macrophage activation. One of these genes, designated macrophage inhibitory cytokine 1 (MIC-1), encodes a protein that bears the structural characteristics of a transforming growth factor beta (TGF-beta) superfamily cytokine. Although it belongs to this superfamily, it has no strong homology to existing families, indicating that it is a divergent member that may represent the first of a new family within this grouping. Expression of MIC-1 mRNA in monocytoid cells is up-regulated by a variety of stimuli associated with activation, including interleukin 1beta, tumor necrosis factor alpha (TNF-alpha), interleukin 2, and macrophage colony-stimulating factor but not interferon gamma, or lipopolysaccharide (LPS). Its expression is also increased by TGF-beta. Expression of MIC-1 in CHO cells results in the proteolytic cleavage of the propeptide and secretion of a cysteine-rich dimeric protein of Mr 25 kDa. Purified recombinant MIC-1 is able to inhibit lipopolysaccharide -induced macrophage TNF-alpha production, suggesting that MIC-1 acts in macrophages as an autocrine regulatory molecule. Its production in response to secreted proinflammatory cytokines and TGF-beta may serve to limit the later phases of macrophage activation.

Background Serum macrophage inhibitory cytokine-1 ( MIC-1/ GDF15) concentration has been associated with colonic adenomas and carcinoma. Aims To determine whether circulating MIC-1/ GDF15 serum concentrations are higher in the presence of adenomas and whether the level decreases after excision. Methods Patients were recruited prospectively from a single centre and stratified into five groups: no polyps ( NP); hyperplastic polyps ( HP); sessile serrated ademona ( SSA); adenomas ( AP); and colorectal carcinoma ( CRC). Blood samples were collected immediately before and 4 weeks after colonoscopy. MIC-1/ GDF15 serum levels were quantified using ELISA. Results Participants (n=301) were stratified as: NP; n=116 (52%), HP; n=37 (12%), SSA; n=19 (7%), AP; n=68 (23%); and CRC; n=3 (1%). Patients were excluded from the study due to nondiagnostic pathology (n=9, 3%) and exclusion criteria (n=20, 6%). In the 272 remaining subjects (M=149; F=123), age ( P=.005), history of colonic polyps ( P=.003) and family history of colonic polyps ( P=.002) were associated with presence of adenomas. Baseline median MIC-1/ GDF15 serum levels increased significantly from NP 609 (460-797) pg/ mL, HP 582 (466-852) pg/ mL, SSA 561 (446-837) pg/ mL to AP 723 (602-1122) pg/ mL and CRC 1107 (897-1107) pg/ mL; ( P<.001). In the pre- and postpolypectomy paired adenoma samples median MIC-1/ GDF15 reduced significantly from 722 (603-1164) pg/ mL to 685 (561-944) pg/ mL ( P=.002). A ROC analysis for serum MIC-1/ GDF15 to identify adenomatous polyps indicated an area under the curve of 0.71. Conclusions Our data suggest that serum MIC-1/ GDF15 has the diagnostic characteristics to increase the detection of colonic neoplasia and improve screening. [ABSTRACT FROM AUTHOR]

Background:Macrophage inhibitory cytokine-1(MIC-1) is a potential modulator of systemic inflammation and nutritional depletion, both of which are adverse prognostic factors in oesophago-gastric cancer (OGC).Methods:Plasma MIC-1, systemic inflammation (defined as plasma C-reactive protein (CRP) of 10 mg l–1 or modified Glasgow prognostic score (mGPS) of 1), and nutritional status were assessed in newly diagnosed OGC patients (n=293). Healthy volunteers (n=35) served as controls.Results:MIC-1 was elevated in patients (median=1371 pg ml–1; range 141–39 053) when compared with controls (median=377 pg ml–1; range 141–3786; P<0.001). Patients with gastric tumours (median=1592 pg ml–1; range 141–12 643) showed higher MIC-1 concentrations than patients with junctional (median=1337 pg ml–1; range 383–39 053) and oesophageal tumours (median=1180 pg ml–1; range 258–31 184; P=0.015). Patients showed a median weight loss of 6.4% (range 0.0–33.4%), and 42% of patients had an mGPS of 1 or plasma CRP of 10 mg l–1 (median=9 mg l–1; range 1–200). MIC-1 correlated positively with disease stage (r2=0.217; P<0.001), age (r2=0.332; P<0.001), CRP (r2=0.314; P<0.001), and mGPS (r2=0.336; P<0.001), and negatively with Karnofsky Performance Score (r2=−0.269; P<0.001). However, although MIC-1 correlated weakly with dietary intake (r2=0.157; P=0.031), it did not correlate with weight loss, BMI, or anthropometry. Patients with MIC-1 levels in the upper quartile showed reduced survival (median=204 days; 95% CI 157–251) when compared with patients with MIC-1 levels in the lower three quartiles (median=316 days; 95% CI 259–373; P=0.036), but MIC-1 was not an independent prognostic indicator.Conclusions:There is no independent link between plasma MIC-1 levels and depleted nutritional status or survival in OGC. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis is characterized by chronic inflammation and proliferation of a number of important elements within the joint including the synovial fibroblasts. Elevated levels of a number of cytokines such as IL-1, IL-2, IL-6, interferon-gamma (IFN-γ), transforming growth factor-β and tumour necrosis factor-alpha (TNF-α) have been detected in the synovial fluid of patients with rheumatoid arthritis and other inflammatory arthritides. It seems likely that local release of such mediators may be responsible for the proliferation and overgrowth of connective tissue elements in these disorders. In order to ascertain whether there was evidence to suggest local production or release of fibroblast growth factors in the joint in inflammatory arthritis, and to determine their identity, cells were obtained from the synovial fluid of 15 patients with chronic inflammatory arthritides. All subjects' synovial fluid cells spontaneously released growth factor activity for fibroblasts. This was present in large amounts, being detectable in culture supernatants diluted to a titre of at least 1/625. By a series of depletion experiments using solid-phase bound antibodies to cytokines, it was possible to demonstrate that this activity was due to TNF-α and platelet-derived growth factor (PDGF). Thus, this study showed for the first time that functionally active PDGF was released front synovial fluid cells. Both PDGF and TNF-α appeared to contribute in approximately equal amounts to this fibroblast growth factor activity, and were synergistic in effect. Thus this study provides evidence for the local production and release of these two cytokines and suggests that together they arc the dominant factors in fibroblast proliferation within the synovial cavity. [ABSTRACT FROM AUTHOR]

Fibrosis in the lung directly underlying the field of irradiation is an almost universal long term sequelae of thoracic irradiation. It is assumed to represent the consequence of direct damage to local tissues and/or vascular endothelium by ionizing radiation. This view, however, is not in keeping with our current understanding of fibrotic processes, which suggest that growth factors for fibroblasts (including platelet-derived growth factor (PDGF), insulin-like growth factor I (IGF-I)) and cytokines stimulating collagen synthesis (notably transforming growth factor-beta) are largely responsible for this process. Since a major source of these factors is the macrophage, present in large numbers within the lung, it appeared possible that radiation-induced fibrosis might be mediated by similar mechanisms. Therefore, a study was designed to determine, first, whether in vitro irradiation of mononuclear phagocytes could induce the release of growth factors for fibroblasts. Second, we wished to ascertain whether these same growth factors might also be secreted by bronchoalveolar cells from humans who had undergone in vivo thoracic irradiation. The results of this study indicate that irradiation of a number of different types of mononuclear phagocytes resulted in the dine-dependent synthesis and release of several growth factors for fibroblasts, including PDGF, tumour necrosis factor-alpha (TNF-α) and IGF-I. Further, cells obtained by bronchoalveolar lavage from patients undergoing thoracic radiation spontaneously released PDGF following irradiation. These findings strongly support the contention that synthesis and release of macrophage-derived growth factors for fibroblasts (particularly PDGF and IGF-I) occur after thoracic irradiation and play a significant role in the pathogenesis of irradiation-induced pulmonary fibrosis in humans. [ABSTRACT FROM AUTHOR]

Fibrosis is a major cause of morbidity and mortality in chronic inflammatory diseases, especially interstitial pulmonary disorders. Fibroproliferation is an important part of this fibrotic response, and is mediated largely through growth factors such as platelet derived growth factor (PDG F). insulin- like growth factor (IGFJ I and tumour necrosis factor-alpha (TNF-α). Although there is some evidence implicating these cytokines in fibrotic disorders, strong evidence in vivo is almost non-existent, in order to ascertain the role that these factors play in inflammatory lung disorders associated with connective tissue discusses, alveolar mononuclear cells have been obtained From subjects by bronchoalveolar lavage and assessed (or the spontaneous release of fibroblast growth factors. The study population consisted of subjects with a variety of different connective tissue disorders, both with and without inflammatory pulmonary complications. it was found that lavage cells spontaneously secreted fibroblast growth factor activits over 24 h with maximum activity detected at 6 to 12 h. Growth factor activity could be detected in most subjects with connective tissue disease-associated inflammatory lung disease and sonic normal subjects, but the amount of growth factor activity was much higher in the former than in the latter. By means of antibody depletion experiments all growth factor activity from lavage cells of normal patients was attributable to TNF-α while patients with interstitial lung disease secreted large amounts of PDGF- and fibronectin in addition to TNF-α, Approximately 40-50%, of the total released growth factor activity could be accounted for by PDGF, and 100% by the combination of PDGF. TNF-α and fibronectin, While TNF-α is released from the bronchoalveolar lavage cells of many subjects. in addition, many patients with interstitial lung disease also release spontaneously, large amounts of fibroblast growth Factor activity attributable to PDG F and fibronectin. [ABSTRACT FROM AUTHOR]

Summary Macrophages play an important role in immune and inflammatory responses, largely through secretion of bioactive molecule such as cytokines. While calcium is known to be an important regulator of this process, less is known about the role of other ions and the ion channels that regulate them. We have previously implicated an outwardly rectifying potassium channel (Kor) in this process and for this reason we have investigated the role of potassium (K+ ) and K+ channels in the regulation of tumour necrosis factor-α (TNF-α )and interleukin (IL)-8 production by activated human culture-derived macrophages. The effect of blockade of Kor is to inhibit phorbol myristate acetate (PMA)-induced cytokine production by translational or post-translational mechanisms, an effect that is duplicated by increasing extracellular K+ . By contrast, the effects of K+ on LPS-stimulated cells are far more complex and are probably mediated through the change of osmolality and occur largely at the mRNA level. This data directly implicates K+ , and its regulation through Kor, in early events following PMA stimulation of these cells. [ABSTRACT FROM AUTHOR]