Linoleic acid increases monocyte chemotaxis and adhesion to human aortic endothelial cells through protein kinase C- and cyclooxygenase-2-dependent mechanisms

The effects of polyunsaturated n-6 linoleic acid on monocyte-endothelial interactions were investigated with particular emphasis on the expression of platelet/endothelial cell adhesion molecule (PECAM)-1 and the role of protein kinase C (PKC) and cyclooxygenase-2 (COX-2). As a diet rich in polyunsaturated fatty acids may favour atherosclerosis in hyperglycaemia, this study was performed in both normal and high-glucose media using human aortic endothelial cells (HAEC). The HAEC were preincubated with normal (5 mM) or high (25 mM) d-glucose for 3 days before addition of fatty acids (0.2 mM) for 3 days. Linoleic acid enhanced PECAM-1 expression independently of tumor necrosis factor (TNF)-a and significantly increased TNF-a-induced monocyte adhesion to HAEC in comparison to the monounsaturated n-9 oleic acid. Chronic glucose treatment (25 mM, 6 days) did not modify the TNF-a-induced or fatty acid-induced changes in monocyte binding. The increase in monocyte binding was accompanied by a significant increase in E-selectin and vascular cell adhesion molecule (VCAM)-1 expression and could be abrogated by an interleukin (IL)-8 neutralising antibody and by the PKC and COX inhibitors. Inhibition of PKC-d reduced VCAM-1 expression regardless of experimental condition and was accompanied by a significant decrease in monocyte binding. Conditioned medium from linoleic acid-treated HAEC grown in normal glucose conditions significantly increased THP-1 chemotaxis. These results suggest that linoleic acid-induced changes in monocyte chemotaxis and subsequent binding are not solely mediated by changes in adhesion molecule expression but may be due to secreted factors such as IL-8, monocyte chemoattractant protein-1 or prostaglandins (PGs) such as PGE2, as IL-8 neutralisation and COX-2 inhibition reduced monocyte binding without changes in adhesion molecule expression.

Claudin-1 Has Tumor Suppressive Activity and Is a Direct Target of RUNX3 in Gastric Epithelial Cells

BACKGROUND & AIMS: The transcription Factor RUNX3 is a gastric tumor suppressor. Tumorigenic Runx3(-/-) gastric epithelial cells attach weakly to each other, compared with nontumorigenic Runx3(+/+) cells. We alined to identify RUNX3 target genes that promote cell-cell contact to Improve our understanding of RUNX3's role in Suppressing gastric carcinogenesis. METHODS: We compared gene expression profiles of Runx3(+/+) and Runx3(-/-) cells and observed down-regulation of genes associated with cell-cell adhesion in Runx3(-/-) cells. Reporter, mobility shift, and chromatin immunoprecipitation assays were used to examine the regulation of these genes by RUNX3. Tumorigenesis assays and immunohistologic, analyses of human gastric tumors were performed to confirm the role of the candidate genes ill gastric tumor development. RESULTS: Mobility shift and chromatin immunoprecipitation assays revealed that the promoter activity of the gene that encodes the tight Junction protein claudin-1 was up-regulated via the binding of RUNX3 to the RUNX consensus sites. The tumorigenicity of gastric epithelial cells From Runx3(-/-) mice was significantly reduced by restoration of claudin-1 expression, whereas knockdown of claudin-1. increased the tumorigenicity of human gastric cancer cells. Concomitant expression of RUNX3 and claudin-1 was observed in human normal gastric epithelium and cancers. CONCLUSIONS: The tight junction protein claudin-1 has gastric tumor suppressive activity and is a direct transcriptional target of RUNX3. Claudin-1 is down-regulated during the epithelial-mesenchymal transition; RUNX3 might therefore act as a tumor suppressor to antagonize the epithelial-mesenchymal transition.

Molecular pathology of RUNX3 in human carcinogenesis

A major goal of molecular biology is to elucidate the mechanisms underlying cancer development and progression in order to achieve early detection, better diagnosis and staging and novel preventive and therapeutic strategies. We feel that an understanding of Runt-related transcription factor 3 (RUNX3)-regulated biological pathways will directly impact our knowledge of these areas of human carcinogenesis. The RUNX3 transcription factor is a downstream effector of the transforming growth factor-beta (TGF-beta) signaling pathway, and has a critical role in the regulation of cell proliferation and cell death by apoptosis, and in angiogenesis, cell adhesion and invasion. We previously identified RUNX3 as a major gastric tumor suppressor by establishing a causal relationship between loss of function and gastric carcinogenesis. More recently, we showed that RUNX3 functions as a bona fide initiator of colonic carcinogenesis by linking the Wnt oncogenic and TGF-beta tumor suppressive pathways. Apart from gastric and colorectal cancers. a multitude of epithelial cancers exhibit inactivation of RUNX3, thereby making it a putative tumor suppressor in human neoplasia. This review highlights our current understanding of the molecular mechanisms of RUNX3 inactivation in the context of cancer development and progression. (C) 2009 Elsevier B.V. All rights reserved.

Derivation of clinically compliant MSCs from CD105+, CD24-differentiated human ESCs

Adult tissue-derived mesenchymal stem cells ( MSCs) have demonstrated therapeutic efficacy in treating diseases or repairing damaged tissues through mechanisms thought to be mediated by either cell replacement or secretion of paracrine factors. Characterized, self- renewing human ESCs could potentially be an invariable source of consistently uniform MSCs for therapeutic applications. Here we describe a clinically relevant and reproducible manner of generating identical batches of hESC- derived MSC ( hESC- MSC) cultures that circumvents exposure to virus, mouse cells, or serum. Trypsinization and propagation of HuES9 or H1 hESCs in feeder- and serum-free selection media generated three polyclonal, karyotypically stable, and phenotypically MSC-like cultures that do not express pluripotency- associated markers but displayed MSC- like surface antigens and gene expression profile. They differentiate into adipocytes, osteocytes, and chondrocytes in vitro. Gene expression and fluorescence- activated cell sorter analysis identified CD105 and CD24 as highly expressed antigens on hESC- MSCs and hESCs, respectively. CD105+, CD24- monoclonal isolates have a typical MSC gene expression profiles and were identical to each other with a highly correlated gene expression profile ( r(2) >.90). We have developed a protocol to reproducibly generate clinically compliant and identical hESC- MSC cultures.

Rational Design of Acridine-Based Ligands with Selectivity for Human Telomeric Quadruplexes

Structure-based modeling methods have been used to design a series of disubstituted triazole-linked acridine compounds with selectivity for human telomeric quadruplex DNAs. A focused library of these compounds was prepared using click chemistry and the selectivity concept was validated against two promoter quadruplexes from the c-kit gene with known molecular structures, as well as with duplex DNA using a FRET-based melting method. Lead compounds were found to have reduced effects on the thermal stability of the c-kit quadruplexes and duplex DNA structures. These effects were further explored with a series of competition experiments, which confirmed that binding to duplex DNA is very low even at high duplex:telomeric quadruplex ratios. Selectivity to the c-kit quadruplexes is more complex, with some evidence of their stabilization at increasing excess over human telomeric quadruplex DNA. Selectivity is a result of the dimensions of the triazole-acridine compounds; and in particular the separation of the two alkyl-amino terminal groups. Both lead compounds also have selective inhibitory effects on the proliferation of cancer cell lines compared to a normal cell line, and one has been shown to inhibit the activity of the telomerase enzyme, which is selectively expressed in tumor cells, where it plays a role in maintaining telomere integrity and cellular immortalization.

Estrogen Receptor-beta Affects the Prognosis of Human Malignant Mesothelioma

Malignant pleural mesothelioma is an asbestos-related neoplasm with poor prognosis, refractory to current therapies, the incidence of which is expected to increase in the next decades. Female gender was identified as a positive prognostic factor among other clinical and biological prognostic markers for malignant mesothelioma, yet a role of estrogen receptors (ERs) has not been studied. Our goal was to investigate ERs expression in malignant mesothelioma and to assess whether their expression correlates with prognosis. Immunohistochemical analysis revealed intense nuclear ER beta staining in normal pleura that was reduced in tumor tissues. Conversely, neither tumors nor normal pleura stained positive for ER alpha. Multivariate analysis of 78 malignant mesothelioma patients with pathologic stage, histologic type, therapy, sex, and age at diagnosis indicated that FRO expression is an independent prognostic factor of better survival. Moreover, studies in vitro confirmed that treatment with 17 beta-estradiol led to an ER beta-mediated inhibition of malignant mesothelioma cell proliferation as well as p21(CIP1) and p27(KIP1) up-regulation. Consistently cell growth was suppressed by ER beta overexpression, causing a G(2)-M-phase cell cycle arrest, paralleled by cyclin B1 and survivin down-regulation. Our data support the notion that ER beta acting as a tumor suppressor is of high potential relevance to prediction of disease progression and to therapeutic response of malignant mesothelioma patients. [Cancer Res 2009;69(11):4598-604]

Docosahexaenoic acid induces an anti-inflammatory profile in lipopolysaccharide-stimulated human THP-1 macrophages more effectively than eicosapentaenoic acid

A number of studies have investigated the effects of fish oil on the production of pro-inflammatory cytokines using peripheral blood mononuclear cell models. The majority of these studies have employed heterogeneous blends of long-chain n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which preclude examination of the individual effects of LC n-3 PUFA. This study investigated the differential effects of pure EPA and DHA on cytokine expression and nuclear factor kappaB (NF-kappaB) activation in human THP-1 monocyte-derived macrophages. Pretreatment with 100 microM EPA and DHA significantly decreased lipopolysaccharide (LPS)-stimulated THP-1 macrophage tumor necrosis factor (TNF) alpha, interleukin (IL) 1beta and IL-6 production (P

Wild-type Measles Virus Infection Upregulates Poliovirus Receptor-Related 4 and Causes Apoptosis in Brain Endothelial Cells by Induction of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand

Small numbers of brain endothelial cells (BECs) are infected in children with neurologic complications of measles virus (MV) infection. This may provide a mechanism for virus entry into the central nervous system, but the mechanisms are unclear. Both in vitro culture systems and animal models are required to elucidate events in the endothelium. We compared the ability of wild-type (WT), vaccine, and rodent-adapted MV strains to infect, replicate, and induce apoptosis in human and murine brain endothelial cells (HBECs and MBECs, respectively). Mice also were infected intracerebrally. All MV stains productively infected HBECs and induced the MV receptor PVRL4. Efficient WT MV production also occurred in MBECs. Extensive monolayer destruction associated with activated caspase 3 staining was observed in HBECs and MBECs, most markedly with WT MV. Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), but not Fas ligand, was induced by MV infection. Treatment of MBECs with supernatants from MV-infected MBEC cultures with an anti-TRAIL antibody blocked caspase 3 expression and monolayer destruction. TRAIL was also expressed in the endothelium and other cell types in infected murine brains. This is the first demonstration that infection of low numbers of BECs with WT MV allows efficient virus production, induction of TRAIL, and subsequent widespread apoptosis.

MicroRNA-34c inversely couples the biological functions of the runt-related transcription factor RUNX2 and the tumor suppressor p53 in osteosarcoma

Osteosarcoma (OS) is a primary bone tumor that is most prevalent during adolescence. RUNX2, which stimulates differentiation and suppresses proliferation of osteoblasts, is deregulated in OS. Here, we define pathological roles of RUNX2 in the etiology of OS and mechanisms by which RUNX2 expression is stimulated. RUNX2 is often highly expressed in human OS biopsies and cell lines. Small interference RNA (siRNA)-mediated depletion of RUNX2 inhibits growth of U2OS OS cells. RUNX2 levels are inversely linked to loss of p53 (which predisposes to OS) in distinct OS cell lines and osteoblasts. RUNX2 protein levels decrease upon stabilization of p53 with the MDM2 inhibitor Nutlin-3. Elevated RUNX2 protein expression is post-transcriptionally regulated and directly linked to diminished expression of several validated RUNX2 targeting microRNAs (miRNAs) in human OS cells compared to mesenchymal progenitor cells. The p53-dependent miR-34c is the most significantly down-regulated RUNX2 targeting miRNA in OS. Exogenous supplementation of miR-34c markedly decreases RUNX2 protein levels, while 3UTR reporter assays establish RUNX2 as a direct target of miR-34c in OS cells. Importantly, Nutlin-3 mediated stabilization of p53 increases expression of miR-34c and decreases RUNX2. Thus, a novel RUNX2-p53-miR34 network controls cell growth of osseous cells and is compromised in OS.

RUNX3 downregulation in human lung adenocarcinoma is independent of p53, EGFR or KRAS status

RUNX3 aberrations play a pivotal role in the oncogenesis of breast, gastric, colon, skin and lung tissues. The aim of this study was to characterize further the expression of RUNX3 in lung cancers. To achieve this, a lung cancer tissue microarray (TMA), frozen lung cancer tissues and lung cell lines were examined for RUNX3 expression by immunohistochemistry, while the TMA was also examined for EGFR and p53 expression. RUNX3 promoter methylation status, and EGFR and KRAS mutation status were also investigated. Inactivation of RUNX3 was observed in 70% of the adenocarcinoma samples, and this was associated with promoter hypermethylation but not biased to EGFR/KRAS mutations. Our results suggest a central role of RUNX3 downregulation in pulmonary adenocarcinoma, which may not be dependent of other established cancer-causing pathways and may have important diagnostic and screening implications.

Prolyl isomerase Pin1 downregulates tumor suppressor RUNX3 in breast cancer

Emerging evidence demonstrates that RUNX3 is a tumor suppressor in breast cancer. Inactivation of RUNX3 in mice results in spontaneous mammary gland tumors, and decreased or silenced expression of RUNX3 is frequently found in breast cancer cell lines and human breast cancer samples. However, the underlying mechanism for initiating RUNX3 inactivation in breast cancer remains elusive. Here, we identify prolyl isomerase Pin1, which is often overexpressed in breast cancer, as a key regulator of RUNX3 inactivation. In human breast cancer cell lines and breast cancer samples, expression of Pin1 inversely correlates with the expression of RUNX3. In addition, Pin1 recognizes four phosphorylated Ser/Thr-Pro motifs in RUNX3 via its WW domain. Binding of Pin1 to RUNX3 suppresses the transcriptional activity of RUNX3. Furthermore, Pin1 reduces the cellular levels of RUNX3 in an isomerase activity-dependent manner by inducing the ubiquitination and proteasomal degradation of RUNX3. Knocking down Pin1 enhances the cellular levels and transcriptional activity of RUNX3 by inhibiting the ubiquitination and degradation of RUNX3. Our results identify Pin1 as a new regulator of RUNX3 inactivation in breast cancer.

RUNX3 acts as a tumor suppressor in breast cancer by targeting estrogen receptor α

Transcription factor RUNX3 is inactivated in a number of malignancies, including breast cancer, and is suggested to function as a tumor suppressor. How RUNX3 functions as a tumor suppressor in breast cancer remains undefined. Here, we show that about 20% of female Runx3(+/-) mice spontaneously developed ductal carcinoma at an average age of 14.5 months. Additionally, RUNX3 inhibits the estrogen-dependent proliferation and transformation potential of ERa-positive MCF-7 breast cancer cells in liquid culture and in soft agar and suppresses the tumorigenicity of MCF-7 cells in severe combined immunodeficiency mice. Furthermore, RUNX3 inhibits ERa-dependent transactivation by reducing the stability of ERa. Consistent with its ability to regulate the levels of ERa, expression of RUNX3 inversely correlates with the expression of ERa in breast cancer cell lines, human breast cancer tissues and Runx3(+/-) mouse mammary tumors. By destabilizing ERa, RUNX3 acts as a novel tumor suppressor in breast cancer.

Retroviral-mediated gene transfer of the human erythropoietin gene into a factor-dependent cell line, TF-1

The factor-dependent cell line, TF-1, established from a patient with erythroleukaemia, shows characteristics of immature erythroblasts. Addition of granulocyte-macrophage colony stimulating factor (GM-CSF) to the culture medium is required for long-term growth of the cells. Erythropoietin (Epo) can also be used to sustain TF-1 cells but for only limited periods (approximately a week). Low levels of both growth factors can act synergistically to maintain proliferation for a longer period of time than Epo alone. To eliminate the requirement of exogenous Epo for growth, TF-1 cells were co-cultured with a retroviral secreting cell line containing the human erythropoietin (hEpo) gene and a neomycin (neo) selectable marker. TF-1 cells which exhibited neo resistance (indicating infection by the retrovirus) were then grown in low concentrations of GM-CSF without the addition of Epo. Under these conditions growth of normal TF-1 cells was not sustained. The neo-resistant cells survived for more than 14 days indicating synergy between GM-CSF and the Epo synthesised by the co-cultured TF-1 cells. Radioimmunoassays performed on growth media detected concentrations up to 1 mU/ml of Epo, implying that stable integration of the retroviral vector and expression of the hEpo gene have been achieved.

V3 versican isoform alters the behavior of human melanoma cells by interfering with CD44/ErbB-dependent signaling

Versican is a hyaluronan-binding, extracellular chondroitin sulfate proteoglycan produced by several tumor types, including malignant melanoma, which exists as four different splice variants. The short V3 isoform contains the G1 and G3 terminal domains of versican that may potentially interact directly or indirectly with the hyaluronan receptor CD44 and the EGFR, respectively. We have previously described that overexpression of V3 in MeWo human melanoma cells markedly reduces tumor cell growth in vitro and in vivo. In this study we have investigated the signaling mechanism of V3 by silencing the expression of CD44 in control and V3-expressing melanoma cells. Suppression of CD44 had the same effects on cell proliferation and cell migration than those provoked by V3 expression, suggesting that V3 acts through a CD44-mediated mechanism. Furthermore, CD44-dependent hyaluronan internalization was blocked by V3 expression and CD44 silencing, leading to an accumulation of this glycosaminoglycan in the pericellular matrix and to changes in cell migration on hyaluronan. Furthermore, ERK1/2 and p38 activation after EGF treatment were decreased in V3-expressing cells suggesting that V3 may also interact with the EGFR through its G3 domain. The existence of a EGFR/ErbB2 receptor complex able to interact with CD44 was identified in MeWo melanoma cells. V3 overexpression resulted in a reduced interaction between EGFR/ErbB2 and CD44 in response to EGF treatment. Our results indicate that the V3 isoform of versican interferes with CD44 and the CD44-EGFR/ErbB2 interaction, altering the signaling pathways, such as ERK1/2 and p38 MAPK, that regulate cell proliferation and migration.