Prostaglandin D2 synthase/prostaglandin D2/TWIST2 signaling inhibits breast cancer proliferation.

Though the past few years have witnessed exciting achievements in targeted and immunotherapeutic treatments of all breast cancer subtypes, yet the decline in breast cancer mortality has been slowed, urging the need for further expanding options of high-quality treatments. Prostaglandin D2 synthase (PTGDS)/prostaglandin D2 (PGD2) play important roles in a variety of cancer types and show tissue-specificity, however, there are limited relevant reports in breast cancer. Therefore, the aims of the present study were to investigate the effects of PTGDS/PGD2 in breast cancer by large-scale bioinformatic analysis and in vitro experiments conducted on human breast cancer cell lines. Results of our study indicated that patients with high levels of PTGDS expression showed a reduced potential of tumor proliferation. PGD2 treatment significantly inhibited the proliferation and migration of breast cancer cells, which was mediated by the reduced expression of TWIST2. Overexpression of TWIST2 reversed the inhibitory effects of PGD2 on breast cancer cell proliferation. These results provided the novel evidence that PTGDS may play a significant role in modulating breast cancer growth, with implications for its potential use in treating breast cancer.

Macrophage migration inhibitory factor regulates joint capsule fibrosis by promoting TGF-ß1 production in fibroblasts.

Joint capsule fibrosis caused by excessive inflammation results in post-traumatic joint contracture (PTJC). Transforming growth factor (TGF)-ß1 plays a key role in PTJC by regulating fibroblast functions, however, cytokine-induced TGF-ß1 expression in specific cell types remains poorly characterized. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in inflammation- and fibrosis-associated pathophysiology. In this study, we investigated whether MIF can facilitate TGF-ß1 production from fibroblasts and regulate joint capsule fibrosis following PTJC. Our data demonstrated that MIF and TGF-ß1 significantly increased in fibroblasts of injured rat posterior joint capsules. Treatment the lesion sites with MIF inhibitor 4-Iodo-6-phenylpyrimidine (4-IPP) reduced TGF-ß1 production and relieved joint capsule inflammation and fibrosis. In vitro, MIF facilitated TGF-ß1 expression in primary joint capsule fibroblasts by activating mitogen-activated protein kinase (MAPK) (P38, ERK) signaling through coupling with membrane surface receptor CD74, which in turn affected fibroblast functions and promoted MIF production. Our results reveal a novel function of trauma-induced MIF in the occurrence and development of joint capsule fibrosis. Further investigation of the underlying mechanism may provide potential therapeutic targets for PTJC.

Inhibition of microRNA-451 is associated with increased expression of Macrophage Migration Inhibitory Factor and mitgation of the cardio-pulmonary phenotype in a murine model of Bronchopulmonary Dysplasia.

BACKGROUND: Macrophage migration inhibitory factor (MIF) has been implicated as a protective factor in the development of bronchopulmonary dysplasia (BPD) and is known to be regulated by MicroRNA-451 (miR-451). The aim of this study was to evaluate the role of miR-451 and the MIF signaling pathway in in vitro and in vivo models of BPD. METHODS: Studies were conducted in mouse lung endothelial cells (MLECs) exposed to hyperoxia and in a newborn mouse model of hyperoxia-induced BPD. Lung and cardiac morphometry as well as vascular markers were evaluated. RESULTS: Increased expression of miR-451 was noted in MLECs exposed to hyperoxia and in lungs of BPD mice. Administration of a miR-451 inhibitor to MLECs exposed to hyperoxia was associated with increased expression of MIF and decreased expression of angiopoietin (Ang) 2. Treatment with the miR-451 inhibitor was associated with improved lung morphometry indices, significant reduction in right ventricular hypertrophy, decreased mean arterial wall thickness and improvement in vascular density in BPD mice. Western blot analysis demonstrated preservation of MIF expression in BPD animals treated with a miR-451 inhibitor and increased expression of vascular endothelial growth factor-A (VEGF-A), Ang1, Ang2 and the Ang receptor, Tie2. CONCLUSION: We demonstrated that inhibition of miR-451 is associated with mitigation of the cardio-pulmonary phenotype, preservation of MIF expression and increased expression of several vascular growth factors.

Differentially Expressed Genes in Matched Normal, Cancer, and Lymph Node Metastases Predict Clinical Outcomes in Patients With Breast Cancer.

Genome-wide screening of transcriptional changes among normal, cancer, and nodal metastases provides insights into the molecular basis of breast cancer (BC) progression and metastasis. To identify transcriptional changes and differentially expressed genes (DEGs) in the metastatic progression of BC and to determine the prognostic role of these DEGs in clinical outcome, we compared transcriptome profiling in matched normal, cancer, and lymph node metastatic tissues of 7 patients with estrogen receptor-positive, HER2-negative BC by using massive parallel RNA sequencing. The global profiles of gene expression in cancer and nodal metastases were highly correlated (r=0.962, P<0.001). In 6 (85.8%) patients, cancer and corresponding nodal metastases from the same patient clustered together. We identified 1522 and 664 DEGs between normal and cancer and between cancer and nodal metastases, respectively. The DEGs in normal versus cancer and cancer versus nodal metastases were significantly clustered in 1 and 8 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. The chemokine signaling pathway was the most significant pathway in the cancer-to-nodal metastasis transition (false discovery rate=2.15E-13). The expression of 2 dysregulated RAC2 and PTGDS genes was confirmed by quantitative real-time polymerase chain reaction and immunohistochemistry. Interestingly, the lower RAC2 and PTGDS expression were associated with significantly worse disease-free survival in patients with BC. Our results show a high concordance of gene expression in BC and their nodal metastases, and identify DEGs associated with the metastatic progression of BC. The DEGs identified in this study represent novel biomarkers for predicting the prognosis of patients with BC.

Effect of NF-kB signaling pathway on the expression of MIF, TNF-α, IL-6 in the regulation of intervertebral disc degeneration.

OBJECTIVE: Τo investigate the effect of NF-kB signaling pathway on the expression of MIF, TNF-α, and IL-6 in the regulation of disc degeneration. METHODS: The disc tissue was taken from 56 patients with cervical spondylosis. According to the preoperative MRI and intraoperative disc herniation, the patients were divided into two groups: degeneration group and herniation group. The control group was 34 patients with cervical trauma with no history of cervical spondylosis. According to the preoperative JOA scores of cervical spondylosis, patients were divided into three groups: mild, moderate and severe. ELISA was used to detect the expression of MIF, IL-6, and TNF-α in the cervical intervertebral disc. NF-kB mRNA expression in the intervertebral disc was detected by qRT-PCR. RESULTS: The expression levels of NF-kB mRNA, MIF, IL-6 and TNF-α in the control group were significantly higher than those in the degeneration group and the herniation group (p⟨0.05). There was a positive correlation between the expression of NF-kB mRNA, MIF, IL-6, TNF- and cervical intervertebral disc degeneration. The expression of MIF, IL-6, and TNF-α in the mild, moderate, and severe group was negatively correlated with the JOA score. CONCLUSIONS: The expressions of NF-kB, MIF, IL-6, and TNF-α in intervertebral disc tissue in patients with disc herniation were increased and related to the degree of disc herniation. It may play an important role in the pathophysiological process of disc herniation.

MiR-608 exerts tumor suppressive function in lung adenocarcinoma by directly targeting MIF.

OBJECTIVE: Lung adenocarcinoma (LA) is considered as a highly aggressive disease with heterogeneous prognosis. The molecular mechanisms of LA progression remain elusive. Recent studies have shown that dysregulation of microRNAs (miRNAs) is prevalent in LA, playing a significant role in tumor progression. The present work aims to analyze the expression and function of miR-608 in LA. PATIENTS AND METHODS: Quantitative Real-time polymerase chain reaction (qRT­PCR) assay and Western blot were performed to detect expressions of miR-608 and migration inhibitory factor (MIF). Luciferase reporter assays were carried out to investigate the regulatory effect of miR-608 on MIF. The cell invasion and the migration capabilities were detected by transwell assay. RESULTS: QRT-PCR indicated that miR-608 expressions in LA tissues were markedly reduced than that of the normal tissues. Moreover, the expression of MIF, a potential target gene of miR-608, was inversely associated with miR-608 expression in LA. Furthermore, miR-608 overexpression could inhibit LA invasion and migration, which was reversed by MIF knockdown. CONCLUSIONS: Our study revealed the mechanisms that miR-608 suppressed LA invasion and migration by targeting MIF, suggesting that miR-608/MIF axis could be used as a potential prognostic biomarker and therapeutic target for LA.

Macrophage migration inhibitory factor is a novel prognostic marker for human oral squamous cell carcinoma.

Macrophage migration inhibitory factor (MIF) is considered a pro-tumour factor. However, its clinical relevance in oral squamous cell carcinoma (OSCC) remains unclear. The objective of this study was to investigate the expression of MIF and its receptor CD74 in OSCC tissues, and to study the function of MIF in OSCC cells. Tissues of 90 patients with OSCC from the School of Stomatology, China Medical University were collected, and immunohistochemical staining and quantitative reverse transcription polymerase chain reaction were performed for MIF and CD74. The possible correlations between MIF and CD74 and clinical characteristics were analysed. The Kaplan-Meier analysis was used to determine the survival rates of patients. In addition, the proliferation and invasion of OSCC cells were evaluated after transfection with siRNA against MIF. MIF and CD74 levels were significantly higher in tissues of patients with OSCC than in control tissues. Moreover, MIF levels in patients with OSCC were significantly associated with cell differentiation and TNM classification. MIF expression was closely related to CD74 expression. Kaplan-Meier analysis indicated that OSCC patients with high MIF levels showed reduced overall survival and recurrenc-free survival. Furthermore, MIF expression promoted proliferation and invasion of OSCC cells. Collectively, our results reveal that MIF expression is a significant independent prognostic factor for patients with OSCC and may be a novel prognostic marker for OSCC.

Soyasaponin Ag inhibits α­MSH­induced melanogenesis in B16F10 melanoma cells via the downregulation of TRP­2.

Saponins, which are glycosylated, represent a diverse group of biologically functional products in plants. In the present study, we investigated the effects of soyasaponin Ag, a secondary metabolite extracted from soybean, on α­melanocyte-stimulating hormone (α­MSH)­induced melanin synthesis in B16F10 mouse melanoma cells and the underlying molecular mechanisms. To elucidate the mechanisms through which soyasaponin Ag inhibits melanin synthesis, we performed cellular tyrosinase activity assays and analyzed the expression of the melanogenesis­related genes, tyrosinase, tyrosinase­related protein (TRP)­1 and TRP­2. We demonstrated that soyasaponin Ag inhibited α­MSH­induced melanin synthesis in melanoma cells. Of note, soyasaponin Ag had no inhibitory effect on intracellular tyrosinase activity. However, soyasaponin Ag inhibited TRP­2 expression in a dose­dependent manner. Therefore, the depigmenting effect of soyasaponin Ag may be due to the inhibition of tyrosinase expression or the enhancement of tyrosinase degradation. Moreover, soyasaponin Ag did not exert any toxic on B16F10 mouse melanoma cells, suggesting that soyasaponin is a safe component for use in skin care cosmetic formulations that are used for skin whitening.

Altered expression of eNOS, prostacyclin synthase, prostaglandin G/H synthase, and thromboxane synthase in porcine aortic endothelial cells after exposure to human serum-relevance to xenotransplantation.

Under normal conditions, the activity of platelets is stringently and precisely balanced between activation and quiescent state. This guarantees rapid hemostasis and avoids uncontrolled thrombosis. However, excessive platelet activation and resulting thrombotic microangiopathy are frequently observed in pig-to-primate xenotransplantation models. Endothelium-derived inhibitory mechanisms play an important role in regulation of platelet activation. These mainly include nitric oxide (NO), prostacyclin PGI2 , and adenosine, which are synthesized by endothelial NO synthases (eNOS), prostacyclin synthase, and CD39/CD73, respectively. We investigated whether endothelium-derived regulatory mechanisms are affected in porcine aortic endothelial cells (PAECs) after exposure to human serum. In the present study, exposure of PAECs or porcine iliac arteries to human serum suppressed gene expression of eNOS and prostacyclin synthase, while induced gene expression of prostaglandin G/H synthase and thromboxane synthase. Simultaneously, exposure to human serum reduced NO and PGI2 production in PAEC culture supernatants. Thus, human serum altered the balance of endothelium-derived inhibitory mechanisms in PAECs, which may indicate a regulatory mechanism of excessive platelet activation in pig-to-primate xenotransplantation.

Combined Knockdown of D-dopachrome Tautomerase and Migration Inhibitory Factor Inhibits the Proliferation, Migration, and Invasion in Human Cervical Cancer.

OBJECTIVE: D-dopachrome tautomerase (D-DT) is a homologue of macrophage migration inhibitory factor (MIF) with similar functions. However, the possible biological roles of D-DT in cervical cancer remain unknown so far. METHODS: D-dopachrome tautomerase was assessed by immunohistochemistry in 83 cervical cancer and 31 normal cervix tissues. The stable knockdown of D-DT and MIF by lentivirus-delivered short hairpin RNA was established, and tumor growth was examined in vitro and in vivo. The effects of D-DT and MIF on the migration and invasion were further detected by wound healing assay and transwell assay. Western blot was used to explore the mechanism of D-DT and MIF in cervical cancer pathogenesis. RESULTS: We found that D-DT was significantly high in cervical cancer, which correlated with lymph node metastasis. The knockdown of D-DT and MIF, individually and additively, inhibited the proliferation, migration, and invasion in HeLa and SiHa cells and restrained the growth of xenograft tumor. The ablation of D-DT and MIF rescued the expression of E-cadherin and inhibited the expression of PCNA, cyclin D1, gankyrin, Sam68, and vimentin, as well as phospho-Akt and phospho-glycogen synthase kinase 3-ß. CONCLUSIONS: The inhibition of D-DT and MIF in combination may represent a potential therapeutic strategy for cervical cancer.

Expression pattern of miR-451 and its target MIF (macrophage migration inhibitory factor) in colorectal cancer.

AIMS: To investigate the expression pattern of microRNA-451 (miR-451) in patients with colorectal carcinoma and correlate with the expression of its target gene MIF (macrophage migration inhibitory factor). METHODS: Matched cancer and non-cancer fresh frozen tissues were prospectively collected from 70 patients (35 men and 35 women) who underwent resection of colorectal adenocarcinoma. These tissues collected were extracted for miR and complementary DNA conversion. Then, miR-451 expressions in these tissues were measured by quantitative real-time PCR. The expression was correlated with clinical and pathological parameters of these patients. In addition, paraffin blocks of 10 colorectal carcinomas with lowest expression of miR-451 were used for the study of MIF protein expression by immunohistochemistry. RESULTS: miR-451 was downregulated in majority of the colorectal cancer tissues when compared with their matched normal tissues (84.3%, n=59/70). Downregulation of miR-451 correlates significantly with presence of coexisting adenoma (91.4%, p=0.025). In addition, persistence of cancer or cancer recurrence after surgery showed significant correlation with downregulation of miR-451 (80% vs 0%; p=0.028). There is no significant correlation between miR-451 expression and age, gender of the patients as well as size, grades, pathological stages, presence of lymphovascular permeation, perineural invasion and microsatellite instability status of the colorectal carcinoma (p>0.05). Majority of the cases (80%) with low expression of miR-451 showed high levels of MIF protein expression confirming the inverse relationship between miR-451 and MIF expressions. CONCLUSIONS: The results showed that miR-451 could play a role in development and progression of colorectal cancer and likely by targeting MIF.

Expression of MIF and c-erbB-2 in endometrial cancer.

The aim of the present study was to investigate the expression of c-erbB-2 and macrophage migration inhibitory factor (MIF) in endometrial cancer and to elucidate the significance of the early diagnosis and prognosis of endometrial cancer. The gene copy number of c­erbB­2 and MIF was characterized by reverse transcription quantitative polymerase chain reaction and the reactivity was assessed by immunohistochemistry in 70 patients using a polyclonal antibody, and evaluated semiquantitatively according to the percentage of cells demonstrating membranous or diffuse cytoplasmic staining. A correlation between age, tumor stage, grade, myometrial invasion and lymph node metastasis was observed. The mRNA expression of c­erbB­2 and MIF was high in endometrial carcinoma. The positive expression rate of MIF protein in normal endometrium, atypical hyperplasia and endometrial carcinoma significantly increased along with the degree of aggravation of the disease by 20 (3/15), 45 (9/20) and 70% (35/50), respectively. The positive expression of MIF and c­erbB­2 was highest in endometrial cancer and a significantly higher level of protein was observed in tumors at stage I, stage G1, with a depth of myometrial invasion <0.4 cm and no lymph node metastasis. The protein expression of c­erbB­2 in endometrial cancer was higher in tumors at the G2­3 phase, clinical stage III­IV, lymph node metastasis, and had no association with the depth of myometrial invasion and age. MIF and c­erbB­2 were correlated with the occurrence and the development of endometrial cancer, and thus can be used for the early diagnosis and prognosis of endometrial cancer. The present study laid the foundation for identifying new treatments for endometrial cancer.

Macrophage migration inhibitory factor promotes breast cancer metastasis via activation of HMGB1/TLR4/NF kappa B axis.

Macrophage migration inhibitory factor (MIF) is up-regulated in diverse solid tumors and acts as the critical link between immune response and tumorigenesis. In this study, we demonstrated that MIF overexpression promoted migration of breast cancer cells by elevating TLR4 expression. Further investigation evidenced that MIF induced ROS generation. MIF-induced ROS led to ERK phosphorylation, which facilitated HMGB1 release from the nucleus to the cytoplasm. MIF overexpression also induced caveolin-1 phosphorylation. Caveolin-1 phosphorylation contributed to HMGB1 secretion from the cytoplasm to the extracellular matrix. The extracellular HMGB1 activated TLR4 signaling including NF-κB phosphorylation, which was responsible for the transcription of Snail and Twist as well as MMP2 activation. Furthermore, MIF-induced caveolin-1-dependent HMGB1 secretion might control the recruitment of CD11b+ immune cells. Our data suggested that MIF affected the intrinsic properties of tumors and the host immune response in tumor microenvironment by regulating the TLR4/HMGB1 axis, leading to metastasis of breast cancer.

Biological characteristics of mouse skin melanocytes.

The objective of this research was to evaluate the optimal passage number according to the biological characteristics of mouse skin melanocytes from different passages. Skin punch biopsies harvested from the dorsal region of 2-day old mice were used to establish melanocyte cultures. The cells from passage 4, 7, 10 and 13 were collected and evaluated for their melanogenic activity. Histochemical staining for tyrosinase (TYR) activity and immunostaining for the melanocyte specific markers including S-100 antigen, TYR, tyrosinase related protein 1 (TYRP1), tyrosinase related protein 2 (TYRP2) and micropthalmia associated transcription factor (MITF) confirmed purity and melanogenic capacity of melanocytes from different passages, with better melanogenic activity of passage 10 and 13 cells being observed. Treatment of passage 13 melanocytes with α-melanocyte stimulating hormone (α-MSH) showed increased expression of MITF, TYR and TYRP2 mRNA. However, considering the TYR mRNA dramatically high expression which is the characteristics of melanoma cells, melanocytes from passage 10 was the optimal passage number for the further research. Our results demonstrate culture of pure populations of mouse melanocytes to at least 10 passages and illustrate the potential utility of passage 10 cells for studies of intrinsic and extrinsic regulation of genes controlling pigmentation and coat color in mouse.

Protein Expression Analysis of Melanocyte Differentiation Antigen TRP-2.

Melanocyte differentiation antigens, such as gp100, tyrosinase, and Melan-A and their corresponding antibodies HMB45, T311, and A103, are major diagnostic tools in surgical pathology. Little is known about tyrosinase-related protein 2 (TRP-2, or dopachrome tautomerase/DCT) another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis. We identified a commercial reagent to TRP-2, monoclonal antibody (mAb) C-9 and undertook a comprehensive analysis to assess its specificity and usefulness for surgical pathology. Subsequently, we analyzed panels of normal tissues and tumors. We show that TRP-2 is regularly expressed in melanocytes of the normal skin. In cutaneous nevi, TRP-2 is present in junctional as well as in dermal nevocytes. In malignant tumors, C-9 reactivity is restricted to melanocytic and related lesions and present in 84% and 58% of primary and metastatic melanomas, respectively. Ten primary melanomas of the anorectal mucosa were all positive. Like the other melanocyte differentiation antigens, TRP-2 was absent in 6 desmoplastic melanomas. Also, only 2 of 9 angiomyolipomas were TRP-2 positive. We conclude that mAb C-9 is a valuable reagent for the analysis of TRP-2 expression in archival surgical pathology material. The expression pattern of TRP-2 in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens, although the overall incidence is lower than other antigens, such as Melan-A or gp100.

Macrophage migration inhibitory factor - a therapeutic target in gallbladder cancer.

BACKGROUND: Poor prognosis in gallbladder cancer is due to late presentation of the disease, lack of reliable biomarkers for early diagnosis and limited targeted therapies. Early diagnostic markers and novel therapeutic targets can significantly improve clinical management of gallbladder cancer. METHODS: Proteomic analysis of four gallbladder cancer cell lines based on the invasive property (non-invasive to highly invasive) was carried out using the isobaric tags for relative and absolute quantitation labeling-based quantitative proteomic approach. The expression of macrophage migration inhibitory factor was analysed in gallbladder adenocarcinoma tissues using immunohistochemistry. In vitro cellular assays were carried out in a panel of gallbladder cancer cell lines using MIF inhibitors, ISO-1 and 4-IPP or its specific siRNA. RESULTS: The quantitative proteomic experiment led to the identification of 3,653 proteins, among which 654 were found to be overexpressed and 387 were downregulated in the invasive cell lines (OCUG-1, NOZ and GB-d1) compared to the non-invasive cell line, TGBC24TKB. Among these, macrophage migration inhibitory factor (MIF) was observed to be highly overexpressed in two of the invasive cell lines. MIF is a pleiotropic proinflammatory cytokine that plays a causative role in multiple diseases, including cancer. MIF has been reported to play a central role in tumor cell proliferation and invasion in several cancers. Immunohistochemical labeling of tumor tissue microarrays for MIF expression revealed that it was overexpressed in 21 of 29 gallbladder adenocarcinoma cases. Silencing/inhibition of MIF using siRNA and/or MIF antagonists resulted in a significant decrease in cell viability, colony forming ability and invasive property of the gallbladder cancer cells. CONCLUSIONS: Our findings support the role of MIF in tumor aggressiveness and suggest its potential application as a therapeutic target for gallbladder cancer.

Macrophage Migration Inhibitory Factor in Acute Adipose Tissue Inflammation.

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and has been implicated in inflammatory diseases. However, little is known about the regulation of MIF in adipose tissue and its impact on wound healing. The aim of this study was to investigate MIF expression in inflamed adipose and determine its role in inflammatory cell recruitment and wound healing. Adipose tissue was harvested from subcutaneous adipose tissue layers of 24 healthy subjects and from adipose tissue adjacent to acutely inflamed wounds of 21 patients undergoing wound debridement. MIF protein and mRNA expression were measured by ELISA and RT-PCR. Cell-specific MIF expression was visualized by immunohistochemistry. The functional role of MIF in cell recruitment was investigated by a chemotaxis assay and by flow cytometry of labeled macrophages that were injected into Mif-/-and wildtype mice. Wound healing was evaluated by an in vitro scratch assay on human fibroblast monolayers. MIF protein levels of native adipose tissue and supernatants from acutely inflamed wounds were significantly elevated when compared to healthy controls. MIF mRNA expression was increased in acutely inflamed adipose tissue indicating the activation of MIF gene transcription in response to adipose tissue inflammation. MIF is expressed in mature adipocytes and in infiltrated macrophages. Peripheral blood mononuclear cell migration was significantly increased towards supernatants derived from inflamed adipose tissue. This effect was partially abrogated by MIF-neutralizing antibodies. Moreover, when compared to wildtype mice, Mif-/-mice showed reduced infiltration of labeled macrophages into LPS-stimulated epididymal fat pads in vivo. Finally, MIF antibodies partially neutralized the detrimental effect of MIF on fibroblast wound healing. Our results indicate that increased MIF expression and rapid activation of the MIF gene in fat tissue adjacent to acute wound healing disorders may play a role in cell recruitment to the site of inflammation and wound healing.

Macrophage migration inhibitory factor involvement in breast cancer (Review).

Macrophage migration inhibitory factor (MIF) is a pleiotropic inflammatory cytokine involved in many cellular processes and in particular carcinogenesis. Here, we review the experimental and clinical published data on MIF and its pathways in breast cancer. Experimental data show that MIF is overexpressed in breast cancer cells (BCC) due, at least partly, to its stabilization by HSP90 and upregulation by HIF-1α. MIF interacts with its main receptor CD74 and its co-receptor CXCR-4, both overexpressed, promoting cell survival by PI3K/Akt activation, a possible link with EGFR and HER2 pathways and inhibition of autophagy. Besides these auto- and paracrine effects on BCC, MIF interacts with BCC microenvironment by several mechanisms: immunomodulation by increasing the prevalence of immune suppressive cells, neo-angiogenesis by its link to HIF-1, and finally BCC transendothelial migration. Clinical studies show higher levels of MIF in breast cancer patients serum compared to healthy volunteers but without obvious clinical significance. In breast cancer tissue, MIF and CD74 are overexpressed in the cancer cells and in the stroma but correlations with classical prognostic factors or survival are elusive. However, an inverse correlation with the tumor size for stromal MIF and a positive correlation with the triple receptor negative tumor status for stromal CD74 seem to be showed. This set of experimental and clinical data shows the involvement of MIF pathways in breast carcinogenesis. Several anti-MIF targeted strategies are being explored in therapeutic goals and should merit further investigations.

Paracrine in vivo inhibitory effects of adipose tissue-derived mesenchymal stromal cells in the early stages of the acute inflammatory response.

BACKGROUND AIMS: Excessive or unresolved inflammation leads to tissue lesions. Adipose tissue-derived mesenchymal stromal cells (AMSCs) have shown protective effects that may be dependent on the modulation of inflammation by secreted factors. METHODS: We used the zymosan-induced mouse air pouch model at two time points (4 h and 18 h) to evaluate the in vivo effects of AMSCs and their conditioned medium (CM) on key steps of the early inflammatory response. We assessed the effects of AMSCs and CM on leukocyte migration and myeloperoxidase activity. The levels of chemokines, cytokines and eicosanoids in exudates were measured by use of enzyme-linked immunoassay or radio-immunoassay. In addition, the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1) was studied by use of Western blotting and the phosphorylation of p65 nuclear factor-κB (NF-κB) by immunofluorescence. RESULTS: All inflammatory parameters were significantly reduced by CM and AMSCs to a similar extent at 4 h after zymosan injection with lower effects at 18 h. The observed inhibition of leukocyte migration was associated with reduced levels of chemokines and leukotriene B4. Interleukin-1ß, interleukin-6, tumor necrosis factor-α and tumor necrosis factor-stimulated gene 6 levels were significantly decreased. The downregulation of mPGES-1 was associated with inhibition of prostaglandin E2 production. Our results suggest that these anti-inflammatory effects are related, in part, to the inhibition of NF-κB activation. CONCLUSIONS: AMSCs dampen the early process of inflammation in the zymosan-induced mouse air pouch model through paracrine mechanisms. These results support the potential utility of these cells as a source of novel treatment approaches for inflammatory pathologies.

Adipocyte Mineralocorticoid Receptor Activation Leads to Metabolic Syndrome and Induction of Prostaglandin D2 Synthase.

Metabolic syndrome is a major risk factor for the development of diabetes mellitus and cardiovascular diseases. Pharmacological antagonism of the mineralocorticoid receptor (MR), a ligand-activated transcription factor, limits metabolic syndrome in preclinical models, but mechanistic studies are lacking to delineate the role of MR activation in adipose tissue. In this study, we report that MR expression is increased in visceral adipose tissue in a preclinical mouse model of metabolic syndrome and in obese patients. In vivo conditional upregulation of MR in mouse adipocytes led to increased weight and fat mass, insulin resistance, and metabolic syndrome features without affecting blood pressure. We identified prostaglandin D2 synthase as a novel MR target gene in adipocytes and AT56, a specific inhibitor of prostaglandin D2 synthase enzymatic activity, blunted adipogenic aldosterone effects. Moreover, translational studies showed that expression of MR and prostaglandin D2 synthase is strongly correlated in adipose tissues from obese patients.