Macrophage migration inhibitory factor in the human prostate: identification and immunocytochemical localization

Translationally controlled tumour protein (TCTP) is present in human cornea and increases in herpetic keratitis

BACKGROUND

Translationally controlled tumour protein is a multifunctional calcium binding protein which has an important role in apoptosis, calcium levels balance and immunological response. The aim of this study was to evaluated the presence and distribution of TCTP in healthy human corneas and to identify and characterize the presence and distribution of this protein in human normal cornea. Since recent studies suggest that apoptosis, calcium levels and immunological mechanisms play a role in the pathogenesis of herpetic stromal keratitis, we studied TCTP expression in this disease.

METHODS

We evaluated the expression of TCTP at both RNA messanger and protein level by using reverse transcriptase analysis, immunoblotting and immunohistochemistry in 10 healthy samples cornea: four obtained after penetrating keratoplasty and six from eyes enucleated for other pathologies. Finally, we analysed by immunohistochemistry ten paraffin-embedded samples of Herpes simplex virus keratitis collected at Siena Department of Human Pathology and Oncology: 5 had clinically quiescent disease and 5 had active corneal inflammation.

RESULTS

Reverse transcriptase and immunoblotting demonstrated TCTP expression in cornea as a 22,000 Da molecular weight band corresponding to the molecular weight of this protein. Immunohistochemically, all the layers of normal corneal epithelium showed TCTP cytoplasmic expression. TCTP was, also, observed in keratocytes and in the endothelium. In Herpes simplex virus keratitis samples, strong expression of TCTP was evident in stromal cells, in the inflammatory infiltrate and in neo-vessels.

CONCLUSIONS

In this preliminary study we demonstrated, for the first time, the presence of TCTP in human cornea, suggesting a potential role in the pathogenesis of herpes virus keratitis.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3306813447428149.

Biological significance of perineural invasion (PNI) in prostate cancer

BACKGROUND

In order to better understand the biological significance of perineural invasion (PNI) in prostate cancer, we aimed to analyze in situ the expression of molecules involved in tumor growth or nerve trophicity.

METHODS

Tissues from 66 radical prostatectomies performed for prostate cancer (40 with PNI and 26 without PNI) were selected and included in a tissue microarray (TMA): PNI areas (when available), cancer far from nerves, and nerves far from cancer. The expression of the following molecules was analyzed using immunohistochemistry on TMA slides: macrophage migration inhibitory factor (MIF) and its receptor CD74, EGF receptor (EGFR), heregulin (HRG) and its receptor ErbB3, and the proliferation marker Ki67.

RESULTS

Cancer cells in the PNI areas showed increased proliferation, EGFR and CD74 expression, when compared to cells far from nerves (P = 0.009, 0.0005, and 0.02, respectively). Moreover, cell proliferation and CD74 staining were increased in cancers with PNI features compared to cancers without PNI (P = 0.001), even when adjusting for Gleason score, tumor size, and pathological stage.

CONCLUSIONS

These results suggest that cancer cells in the PNI areas could acquired a growth advantage that could be triggered by the growth factor receptors EGFR and CD74.

Further evidence for increased macrophage migration inhibitory factor expression in prostate cancer

Background

Macrophage migration inhibitory factor (MIF) is a cytokine associated with prostate cancer, based on histologic evidence and circulating (serum) levels.

Recent studies from another laboratory failed to document these results. This study's aims were to extend and confirm our previous data, as well as to define possible mechanisms for the discrepant results. Additional aims were to examine MIF expression, as well as the location of MIF's receptor, CD74, in human prostatic adenocarcinoma compared to matched benign prostate.

Methods

MIF amounts were determined in random serum samples remaining following routine PSA screening by ELISA. Native, denaturing and reducing polyacrylamide gels and Western blot analyses determined the MIF form in serum. Prostate tissue arrays were processed for MIF in situ hybridization and immunohistochemistry for MIF and CD74. MIF released into culture medium from normal epithelial, LNCaP and PC-3 cells was detected by Western blot analysis.

Results

Median serum MIF amounts were significantly elevated in prostate cancer patients (5.87 ± 3.91 ng/ml; ± interquartile range; n = 115) compared with patients with no documented diagnosis of prostate cancer (2.19 ± 2.65 ng/ml; n = 158). ELISA diluent reagents that included bovine serum albumin (BSA) significantly reduced MIF serum detection (p < 0.01). MIF mRNA was localized to prostatic epithelium in all samples, but cancer showed statistically greater MIF expression. MIF and its receptor (CD74) were localized to prostatic epithelium. Increased secreted MIF was detected in culture medium from prostate cancer cell lines (LNCaP and PC-3).

Conclusion

Increased serum MIF was associated with prostate cancer. Diluent reagents that included BSA resulted in MIF serum immunoassay interference. In addition, significant amounts of complexed MIF (180 kDa under denaturing conditions by Western blot) found in the serum do not bind to the MIF capture antibody. Increased MIF mRNA expression was observed in prostatic adenocarcinoma compared to benign tissue from matched samples, supporting our earlier finding of increased MIF gene expression in prostate cancer.

Translationally controlled tumor protein (TCTP) in the human prostate and prostate cancer cells: expression, distribution, and calcium binding activity

BACKGROUND

The translationally controlled tumor protein (TCTP) is an abundantly expressed protein found in a wide range of organisms from both the animal and plant kingdom. Initially described as a growth-related protein, knowledge of the biological actions of TCTP has been recently extended to include calcium binding, regulation of apoptosis, and microtubules stabilization. This report describes expression, distribution, and characterization of TCTP in human prostatic tissues and cell lines.

METHODS

Samples were analyzed by Western blot, RT-PCR, immunohistochemistry, and confocal microscopy. Calcium binding activity of the recombinant human prostatic protein was evaluated on a calcium overlay assay. A public SAGE database was analyzed to determine TCTP expression levels in normal and cancer tissues.

RESULTS

TCTP protein and mRNA were detected in all the specimens and cell lines analyzed. The protein was mainly expressed by the secretory luminal epithelial and basal layer cells. A significant amount of protein was present in the prostatic fluids. Subcellular distribution studies in prostate epithelial cells detected the protein in the cytoplasm in interphase and colocalized with tubulin during mitosis. The calcium binding capacity of prostatic TCTP was shown in vitro. Finally, SAGE data indicated TCTP as the calcium binding protein with the highest expression levels among those examined.

CONCLUSIONS

The results of the present study demonstrate, for the first time, the expression of TCTP in the human prostate and in prostate cancer cells, and suggest the involvement of the protein in key-processes such as apoptosis, cellular differentiation, and in the control of sperm functions.

Prostatic androgen repressed message-1 (PARM-1) may play a role in prostatic cell immortalisation

BACKGROUND

Prostatic androgen-repressed message-1 (PARM-1) has been cloned from the prostate. The transcript of the PARM-1 gene is overexpressed during regression of the prostate after androgen withdrawal. The regulation of PARM-1 by androgens is limited to this organ. We have studied the effects of PARM-1 overexpression in malignant prostate cells.

METHODS

The PARM-1 cDNA was introduced into the rat cancer cell line MAT LyLu along with a doxycycline-dependent regulator.

RESULTS

Maximal expression of PARM-1 (fivefold induction) was achieved by incubating the cells with 2 microM doxycycline for 48 hr. A study investigating the effect of PARM-1 overexpression on the transcription of 588 genes has shown that the TLP1 gene (encoding rat telomerase protein component 1) was the most up-regulated (fourfold). In addition, a dose-dependent increase in telomerase activity was observed in cells overexpressing PARM-1. In vivo, the androgen-deprived prostate showed an increased TLP1 level and increased telomerase activity.

CONCLUSIONS

Increased telomerase activity is often associated with the immortalisation of cancer cell lines, particularly prostatic ones. This could mean that PARM-1 is involved, via increased telomerase activity, in a survival program enabling certain prostatic cells to resist apoptosis, thus conferring a selective advantage to pre-cancerous or cancerous cells.

Recombinant adenovirus vector bearing antisense macrophage migration inhibitory factor cDNA prevents acute lipopolysaccharide-induced liver failure in mice

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine involved in delayed hypersensitivity and cellular immunity. MIF also acts as a proinflammatory cytokine and counterregulates the anti-inflammatory effects of glucocorticoids. Exogenous gene transfer mediated by adenovirus is useful to study a particular molecular function as well as to develop gene therapy strategies. A recombinant adenovirus containing sense and antisense murine MIF (mMIF) cDNA inserts was constructed using a cosmid-terminal protein complex method. The sense mMIF adenovirus (AxCA-mMIFS) efficiently induced mMIF in COS-7 cells that endogenously lack mMIF in a dose-dependent manner. In contrast, the antisense mMIF adenovirus (AxCA-mMIFAS) inhibited the expression of mMIF in NIH3T3 cells in a dose-dependent manner. To assess the pathophysiologic role of MIF in acute liver failure, we induced acute onset of liver damage in mice (male Jcl:ICR) by a combined treatment of Bacille Calmette-Guerin (BCG) and lipopolysaccharide (LPS). mMIF level in the liver of mice infected with AxCA-mMIFAS showed a significant reduction in MIF production in response to BCG-LPS compared with mice treated without viral infection and with AxCA-mMIFS. In addition, the immunohistochemical staining demonstrated that F4/80 antigen on macrophage was enhanced in liver infected with AxCA-mMIFS but reduced in liver infected with AxCA-mMIFAS. The staining intensity is correlated with the mMIF antigen level in liver tissue. The survival rate of mice infected with AxCA-mMIFAS was significantly higher than that of mice treated with PBS and infected with AxCA-LacZ in BCG-LPS. These results suggest that inhibition of MIF production, using recombinant adenovirus bearing the antisense MIF gene, reduced the mortality rate in BCG-LPS-induced liver failure in mice. This finding might aid in the further development of gene therapy targeting MIF.

Expression of urocortin mRNA and peptide in the human prostate and in prostatic adenocarcinoma

BACKGROUND

Urocortin (UCN) is a recently described neuropeptide member of the CRF family, responsible for the secretion of the proopiomelanocortin-derived peptides from the pituitary gland. Although previous results have demonstrated the synthesis of several neuroendocrine factors in the prostate, no studies have been carried out on the expression of UCN in the human gland.

METHODS

UCN expression was evaluated in benign prostatic hyperplasia and prostatic tumor tissues by RT-PCR and immunohistochemistry.

RESULTS

UCN mRNA and peptide were demonstrated in all specimens tested. In nonneoplastic tissues, UCN was localized in the secretory luminal epithelial and basal layer cells, in the smooth muscle component of the stroma, and in lymphoid infiltrates. An intense immunostaining was evident in prostate adenocarcinoma cells.

CONCLUSIONS

The results of the present study demonstrate for the first time UCN expression in the human prostate and in prostate cancer, and suggest a potential involvement of UCN in prostate physiopathology.

Expression profile of differentially-regulated genes during progression of androgen-independent growth in human prostate cancer cells

Because of the heterogeneous nature of prostate cancer, identifying the molecular mechanisms involved during the transition from an androgen-sensitive to an androgen-independent phenotype is very complex. An LNCaP cell model that recapitulates prostate cancer progression, comprising early passage androgen-sensitive (LNCaP-C33) and late passage androgen-independent (LNCaP-C81) phenotypes, would help to provide a better understanding of such molecular events. In this study, we examined the genes expressed by LNCaP-C33 and LNCaP-C81 cells using cDNA microarrays containing 1176 known genes. This analysis demonstrated that 34 genes are up-regulated and eight genes are down-regulated in androgen-independent cells. Northern blot analysis confirmed the differences identified by microarrays on several candidate genes, including c-MYC, c-MYC purine-binding transcription factor (PuF), macrophage migration inhibitory factor (MIF), macrophage inhibitory cytokine-1 (MIC-1), lactate dehydrogenase-A (LDH-A), guanine nucleotide-binding protein Gi, alpha-1 subunit (NBP), cyclin dependent kinase-2 (CDK-2), prostate-specific membrane antigen (PSM), cyclin H (CCNH), 60S ribosomal protein L10 (RPL10), 60S ribosomal protein L32 (RPL32), and 40S ribosomal protein S16 (RPS16). These differentially-regulated genes are correlated with progression of human prostate cancer and may be of therapeutic relevance as well as an aid in understanding the molecular genetic events involved in the development of this disease's hormone-refractory behavior.

Presence of macrophage migration inhibitory factor in human milk: evidence in the aqueous phase and milk fat globules

Human milk is a source of bioactive substances regulating the development and activity of the newborn immune system. Human milk has been found to contain a number of cytokines, including interleukins, growth factors, and colony stimulating factors. In the present study, we assessed 10 specimens of human milk for the presence of macrophage migration inhibitory factor (MIF), a cytokine recently described in several human reproductive organs and tissues. Using biochemical as well as immunologic techniques, we showed that MIF is abundantly present in human milk, mostly distributed in the lipid layer and in the aqueous phase. Fractionation of the lipid layer showed that MIF is highly concentrated inside milk fat globules. In view of its proinflammatory features, we speculate that milk MIF may protect the newborn against infection and play a role in preserving the functionality of the lactating mammary gland. Furthermore, the localization of MIF in lipid globules suggests a possible strategy for the protection of milk cytokines from the gastric barrier.

Macrophage migration inhibitory factor evaluation compared with prostate specific antigen as a biomarker in patients with prostate carcinoma

BACKGROUND

Cytokines are polypeptides that constitute a class of chemical mediator molecules that modulate cell growth by inducing specific target gene expression. The objective of this study was to evaluate the clinical usefulness of serum evaluation of the cytokine macrophage migration inhibitory factor (MIF) in patients undergoing routine prostate specific antigen (PSA) screening.

METHODS

In this preliminary, retrospective study, the authors report the development of an enzyme-linked immunosorbent assay (ELISA) for MIF determination in serum samples. A polymerase chain reaction (PCR)-based assay investigated associations between MIF expression and prostate carcinoma (CaP). The authors developed a relative quantitative reverse transcriptase-PCR assay to determine MIF mRNA amounts within laser-capture microscopy (LCM)-dissected prostate epithelial cells.

RESULTS

A comparison of serum MIF levels and total PSA levels identified a positive correlation (correlation coefficient [r2] = 0.61; P < 0.001; n = 509 patients), suggesting an association between elevated serum concentrations of these proteins and CaP. A correlation of serum MIF levels with a diagnosis of CaP demonstrated that patients with a previous CaP diagnosis had significantly elevated serum MIF concentrations (mean +/- standard deviation, 6.8 +/- 0.87 ng/mL; P < 0.001). To associate altered serum MIF levels with MIF mRNA expression within prostate epithelial cells, LCM-dissected prostate epithelial cells (formalin fixed biopsies from three different patients) were used to determine MIF mRNA amounts by PCR analysis. On average, MIF mRNA amounts were 6.5 times higher in CaP epithelial cells that were invasive to the margin compared with MIF mRNA amounts in normal prostate epithelial cells within the same biopsy specimen.

CONCLUSIONS

The ELISA data from the current study suggested an association between increased MIF expression and CaP and suggested that serum MIF concentration may serve as a prognostic marker for CaP.

Macrophage migration inhibitory factor in the human endometrium: expression and localization during the menstrual cycle and early pregnancy

Macrophage migration inhibitory factor (MIF) was discovered as an activated T-lymphocyte-derived protein that inhibits the random migration of macrophages in vitro. Subsequently, knowledge of the physiological actions of MIF was extended to include its role as a proinflammatory cytokine that affects several functions of macrophages and lymphocytes. Previous reports have suggested an involvement of MIF in reproduction. However, no data are currently available on the presence of this cytokine in the human endometrium. In this study, the expression and tissue localization of MIF was evaluated in specimens of cycling endometrium, first trimester placenta bed biopsy, and isolated endometrial glands by Western blot analysis, immunohistochemistry, ELISA, and reverse transcription-polymerase chain reaction. The results demonstrated that MIF is expressed in human endometrium across the menstrual cycle and in early pregnancy. Immunohistochemical localization identified the protein in glandular epithelium, in stromal and predecidualized stromal cells of cycling endometrium, as well as in the decidua of first-trimester placenta. The proinflammatory features and specific actions of MIF on lymphoid cells suggest its potential involvement in several aspects of endometrial physiology.

Macrophage migration inhibitory factor in prostatic adenocarcinoma: correlation with tumor grading and combination endocrine treatment-related changes

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a ubiquitary cytokine whose expression has been investigated in tumors, showing a correlation between tumor aggressiveness and production of this protein by neoplastic cells. The aim of our study was to correlate MIF expression with tumor grade (Gleason scoring system) and histopathological changes after combined endocrine treatment (CET) of prostate adenocarcinoma.

METHODS

We analyzed MIF immunoreactivity in 124 paired needle biopsies and radical prostatectomy specimens from 62 prostate cancer patients, of which 20 had been treated with CET.

RESULTS

In untreated prostates, MIF expression significantly correlated with tumor grading, being stronger in low-grade than in high-grade adenocarcinoma. In treated prostates, histopathological changes also correlated with MIF immunoreactivity, but not in a significant manner.

CONCLUSIONS

The results of the current study demonstrated that with histological dedifferentiation, prostate adenocarcinoma cells show a reduced MIF expression. This finding may be the consequence of a reduced MIF synthesis or the result of an enhanced and altered secretion by tumor cells into the surrounding stroma. The consequent abnormal interaction between MIF and environmental factors might influence tumor growth and diffusion. On the other hand, the minor but not significantly reduced MIF expression by tumor cells after CET seems to exclude a hormonal regulation of MIF secretion.

Increased stability of macrophage migration inhibitory factor (MIF) in DU-145 prostate cancer cells

Macrophage migration inhibitory factor (MIF) has been localized to the glandular epithelium of the prostate and stimulates the in vitro growth of prostate epithelial cells. [35S]Methionine labeling of MIF protein was used to determine if prostate cells synthesize and secrete this cytokine. The results demonstrated that the DU-145 prostate cancer cells secrete about twice the amount of a more stable protein compared with normal prostate epithelial cells. To investigate if differences in MIF mRNA levels account for the differences in MIF protein secreted by these cells, mRNA stability was analyzed by [3H]uridine incorporation. Following a 12-h pulse, DU-145 cells were found to contain four times the amount of [3H]uridine-labeled MIF mRNA, and this message exhibited a longer half-life than the message found in normal cells (33 h and 19 h, respectively). Nuclear run-on experiments confirmed that the MIF gene is transcribed at a greater rate (1.8-fold) in the DU-145 prostate cancer cells. This study documents, for the first time, that human prostate epithelial cells synthesize and secrete this cytokine. These results indicate that the increased levels of MIF found in prostate cancer cells is likely due to the increased protein and mRNA stability as exhibited by DU-145 cells.

Macrophage migration inhibitory factor increases MMP-2 activity in DU-145 prostate cells

Macrophage migration inhibitory factor (MIF) is a cytokine expressed by a number of different cell types and has been detected in prostatic glandular epithelial cells by immunohistochemistry. The goal of this study was to determine if in vitro cultured prostate cells produce this protein and some of the effects of MIF on these cells. Proliferation of normal prostate cells, the BPH-1 and DU-145 established cell lines in the presence of MIF were assessed. ELISA was used to screen conditioned medium for the production of MIF, matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2). Zymogram electrophoresis gels determined the activities of secreted MMP-2. The amount of MIF in the conditioned medium detected after 72 h of growth in normal, BPH-1 and DU-145 cells was 2.9, 5.2 and 10.2 ng/ml/10(6)cells respectively. Exogenous addition of MIF (25 ng/ml) to cells cultured in vitro stimulated proliferation of all the cell types tested. MIF addition to proliferating DU-145 cells resulted in a two-fold increase in the relative amount of active MMP-2 as determined by zymogram gel analysis of conditioned medium.