Increased Expression Of Osteopontin Research Articles

Hydrogen Peroxide Regulates Osteopontin Expression through Activation of Transcriptional and Translational Pathways

Recent in vivo studies establish that osteopontin (OPN) expression is hydrogen peroxide (H2O2)-dependent. However, the mechanisms by which H2O2 increases OPN expression remain poorly defined. OPN protein expression increased in an unusual biphasic pattern in response to H2O2. To investigate whether these increases were mediated through transcriptional and/or translational regulation of OPN, smooth muscle cells stimulated with 50 μM H2O2 were used as an in vitro cell system. Early protein increases at 6 h were not preceded by increased mRNA, whereas later increases (18 h) were, suggesting multiple mechanisms of regulation by H2O2. Polyribosomal fractionation assays established that early increases (6 h) in OPN expression were due to increased translation. This increase in translation occurred through phosphorylation of 4E-BP1 at the reactive oxygen species-sensitive Ser-65, which allowed for release and activation of eukaryotic initiation factor eIF4E and subsequent OPN translation. This early increase (6 h) in OPN was blunted in cells expressing a phospho-deficient 4E-BP1 mutant. H2O2 stimulation increased rat OPN promoter activity at 8 and 18 h, and promoter truncation studies established that promoter region -2284 to -795 is crucial for H2O2-dependent OPN transcription. ChIP studies determined that H2O2-dependent transcription is mediated by the reactive oxygen species-sensitive transcription factors NF-κB and AP-1. In conclusion, H2O2 stimulates OPN expression in a unique biphasic pattern, where early increases are translational and late increases are transcriptional.

Evaluation of circulating osteopontin levels in an unselected cohort of patients with multiple sclerosis: relevance for biomarker development

Background: Osteopontin (OPN) is a pleiotropic protein with important roles in inflammation and immunity that has been suggested as a candidate biomarker for disease activity in multiple sclerosis (MS). Objective: We evaluated plasma levels of OPN in an unselected cohort of MS patients, to determine its potential as a biomarker for disease subtype and/or disease activity in a regular clinical setting. Methods: We analyzed OPN plasma levels in 492 consecutive MS patients, using a commercial enzyme-linked immunosorbent assay (ELISA). Results: OPN levels were higher in relapsing–remitting and secondary progressive MS, compared to healthy controls. Treatment with natalizumab or glatiramer acetate was associated with lower OPN levels. There was no significant association between the OPN levels and disease activity, as measured by clinical or radiological criteria. One-third of patients with high OPN levels had concurrent disorders that may also be associated with increased OPN expression, and which may mask a modest effect of MS disease activity on OPN levels. Conclusion: Our data do not support a role for circulating OPN levels as a biomarker for disease activity in a heterogeneous clinical setting, but does not rule out a potential role in the cerebrospinal fluid, in a controlled setting such as a clinical trial, or in concert with other biomarkers.

Increased osteopontin expression is associated with progression from vulvar precancerous lesions to vulvar squamous cell carcinoma

Vulvar squamous cell carcinoma (VSCC) contributes to about 3-5% of all gynecological cancers. Vulvar intraepithelial neoplasia (VIN) and vulvar lichen sclerosus (VLS) are regarded as precancerous lesions. Early detection and treatment of precancerous lesions may prevent development of VSCC. Osteopontin (OPN) has been shown to be involved in many physiological and pathological processes, such as tumor progression, by promoting cancer cell invasion and metastasis. As a result of these findings, OPN has been described as a potential marker for tumor progression in some malignancies. In this study, we investigated the expression of OPN in vulvar tissue specimens and compared its expression between different histopathological grades. In the present study, the expression patterns of OPN in 80 paraffin-embedded tissue specimens, including 25 VSCC samples, 21 VIN lesions and 21 VLS, in addition to 13 normal vulvar samples, were examined by the immunohistochemical method and chromogenic in situ hybridization. The intensity of OPN expression steadily increased according to the pathological grades. In addition, OPN staining was found in the extracellular matrix in VSCC. Expression levels of OPN increased from VLS and VIN to VSCC, and steadily increased with the pathological stage of VSCC. Our results suggest that OPN may be associated with the progression of VSCC.

Loss of RUNX3 increases osteopontin expression and promotes cell migration in gastric cancer

Loss of RUNX3 expression is frequently observed in gastric cancer and is highly associated with lymph node metastasis and poor prognosis. However, the underlying molecular mechanisms of gastric cancer remain unknown. In this study, we found that the protein levels of RUNX3 and osteopontin (OPN) are inversely correlated in gastric cancer clinical specimens and cell lines. Furthermore, similar inverse trends between RUNX3 and OPN messenger RNA (mRNA) expression were demonstrated in six out of seven normal-tumor-paired gastric cancer clinical specimens. In addition, low RUNX3 and high OPN expression were associated with poor prognosis in gastric cancer patients. Ectopic expression of green fluorescent protein-RUNX3 reduced OPN protein and mRNA expression in the AGS and SCM-1 gastric cancer cell lines. In contrast, knockdown of RUNX3 in GES-1, a normal gastric epithelial cell line, increased OPN expression. Although three RUNX3-binding sequences have been identified in the OPN promoter region, direct binding of RUNX3 to the specific binding site, -142 to -137bp, was demonstrated by chromatin immunoprecipitation assay. The binding of RUNX3 to the OPN promoter significantly decreased OPN promoter activity. The knockdown of OPN or overexpression of RUNX3 inhibited cell migration in AGS and SCM-1 cells; however, the coexpression of RUNX3 and OPN reversed the RUNX3-reduced migration ability in AGS and SCM-1 cells. In contrast, the knockdown of both RUNX3 and OPN inhibited RUNX3-knockdown-induced migration of GES-1 cells. Together, our data demonstrated that RUNX3 is a transcriptional repressor of OPN and that loss of RUNX3 upregulates OPN, which promotes migration in gastric cancer cells.

Increased osteopontin expression in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patient cells is associated with IL-17 expression

BackgroundHTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurological inflammatory disease associated with a predominant infiltration of CD4+ T lymphocytes, which are the main subset of HTLV-1-infected cells. It has been demonstrated that in cell line the viral Tax protein transcriptionnally regulate expression of osteopontin, an inflammatory cytokine associated with Th17-related pathologies. ObjectivesThe aim of the study was to explore osteopontin expression in HTLV-1 asymptomatic carriers and in HAM/TSP patients and consequences on IL17 expression. Study designWe quantified Tax, osteopontin, RORγ, IL17 and IL22 mRNA expressions in cells from 10 HAM/TSP patients, 6 asymptomatic HTLV-1 carriers (ASY) and 4 HTLV-1-negative healthy donors during ex vivo culture. ResultsWe observed that the expression of osteopontin was higher in HAM/TSP patients and correlated with Tax expression levels. Positive regulation of RORγ, IL17 and IL22 were also observed during cell culture. ConclusionsOur results propose a new mechanism which could contribute to HAM/TSP pathogenesis.

Hydrogen peroxide-induced poly(ADP-ribosyl)ation regulates osteogenic differentiation-associated cell death

We set out to investigate the role of poly(ADP-ribosylation), the attachment of NAD+-derived (ADP-ribose)n polymers to proteins, in the regulation of osteogenic differentiation of SAOS-2 cells and mesenchymal stem cells. In osteogenic differentiation medium, SAOS-2 cells showed mineralization and expressed alkaline phosphatase and osteoblastic marker genes such as Runx2, osterix, BMP2, and osteopontin. The cells also released hydrogen peroxide, displayed poly(ADP-ribose) polymerase (PARP) activation, and showed commitment to cell death (apoptosis and necrosis). Scavenging reactive oxygen species by glutathione or decomposing hydrogen peroxide by the addition of catalase reduced differentiation, PARP activation, and cell death. We silenced the expression of the main PAR-synthesizing enzyme PARP-1 and the PAR-degrading enzyme poly(ADP-ribose) glycohydrolase (PARG) in SAOS-2 osteosarcoma cells (shPARP-1 and shPARG, respectively). Both shPARP-1- and shPARG-silenced cells exhibited altered differentiation, with the most notable change being increased osteopontin expression but decreased alkaline phosphatase activity. PARP-1 silencing suppressed both apoptotic and necrotic cell death, but the PARP inhibitor PJ34 sensitized cells to cell death, indicating that the effects of PARP-1 silencing are not related to the activity of the enzyme. PARG silencing resulted in more apoptosis and, in the last days of differentiation, a shift from apoptosis toward necrosis. In conclusion our data prove that hydrogen peroxide-induced poly(ADP-ribose) signaling regulates cell death and osteodifferentiation.

Regulation of the pro-inflammatory cytokine osteopontin by GIP in adipocytes – A role for the transcription factor NFAT and phosphodiesterase 3B

The incretin – glucose-dependent insulinotropic polypeptide (GIP) – and the pro-inflammatory cytokine osteopontin are known to have important roles in the regulation of adipose tissue functions. In this work we show that GIP stimulates lipogenesis and osteopontin expression in primary adipocytes. The GIP-induced increase in osteopontin expression was inhibited by the NFAT (the transcription factor nuclear factor of activated T-cells) inhibitor A-285222. Also, the NFAT kinase glycogen synthase kinase (GSK) 3 was upregulated by GIP. To test whether cAMP might be involved in GIP-mediated effects on osteopontin a number of strategies were used. Thus, the β3-adrenergic receptor agonist CL316,243 stimulated osteopontin expression, an effects which was mimicked by OPC3911, a specific inhibitor of phosphodiesterase 3. Furthermore, treatment of phosphodiesterase 3B knock-out mice with CL316,243 resulted in a dramatic upregulation of osteopontin in adipose tissue which was not the case in wild-type mice. In summary, we delineate mechanisms by which GIP stimulates osteopontin in adipocytes. Given the established link between osteopontin and insulin resistance, our data suggest that GIP by stimulating osteopontin expression, also could promote insulin resistance in adipocytes.

Hepatocyte Growth Factor Increases Osteopontin Expression in Human Osteoblasts through PI3K, Akt, c-Src, and AP-1 Signaling Pathway

BackgroundHepatocyte growth factor (HGF) has been demonstrated to stimulate osteoblast proliferation and participated bone remodeling. Osteopontin (OPN) is a secreted phosphoglycoprotein that belongs to the SIBLING family and is present during bone mineralization. However, the effects of HGF on OPN expression in human osteoblasts are large unknown.Methodology/Principal FindingsHere we found that HGF induced OPN expression in human osteoblasts dose-dependently. HGF-mediated OPN production was attenuated by c-Met inhibitor and siRNA. Pretreatment of osteoblasts with PI3K inhibitor (Ly294002), Akt inhibitor, c-Src inhibitor (PP2), or AP-1 inhibitor (curcumin) blocked the potentiating action of HGF. Stimulation of osteoblasts with HGF enhanced PI3K, Akt, and c-Src activation. In addition, incubation of cells with HGF also increased c-Jun phosphorylation, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the OPN promoter. HGF-mediated AP-1-luciferase activity and c-Jun binding to the AP-1 element was reduced by c-Met inhibitor, Ly294002, Akt inhibitor, and PP2.Conclusions/SignificanceOur results suggest that the interaction between HGF and c-Met increases OPN expression in human osteoblasts via the PI3K, Akt, c-Src, c-Jun, and AP-1 signaling pathway.

Aldosterone-induced osteopontin expression in vascular smooth muscle cells involves MR, ERK, and p38 MAPK

Osteopontin (OPN) is known to be one of the cytokines that is involved in the vascular inflammation caused by aldosterone (Ald). Previous reports have shown that Ald increases OPN expression, and the mechanisms for this remain to be clarified. In this study, we investigated how Ald increases OPN expression in the vascular smooth muscle cells (VSMCs) of rats. Ald increased OPN expression time dependently as well as dose dependently. This increase was diminished by spironolactone, a mineralocorticoid receptor (MR) antagonist. PD98059, an inhibitor of p42/44 MAPK pathway, and SB203580, an inhibitor of p38 MAPK pathway, suppressed Ald-induced OPN expression and secretion in VSMCs. VSMCs migration stimulated by aldosterone required OPN expression. In conclusion, these data suggest that Ald-induced OPN expression in VSMC is mediated by MR and signaling cascades involving ERK and p38 MAPK. These molecules may represent therapeutic targets for the prevention of pathological vascular remodeling.

Abstract 202: Hydrogen Peroxide Increases Osteopontin Expression Through Activation of Transcriptional and Translational Pathways

The occlusion of blood vessels in the setting of cardiovascular disease leads to ischemia, initiating processes that promote neovascularization to restore blood flow and preserve tissue function. Our in vivo studies show that Osteopontin (OPN) is a critical mediator of post-ischemic neovascularization and that ischemia-induced increases in OPN expression are H 2 O 2 -dependent. However, the mechanisms by which H 2 O 2 increases OPN expression are poorly defined. To determine if H 2 O 2 mediates transcriptional, post-transcriptional, and/or translational regulation of OPN expression in vitro, we used rat aortic smooth muscle cells as an in vitro system and stimulated with H 2 O 2 . Dose response studies showed OPN expression increased with 50 μM H 2 O 2 (51.9%±2.2, p<0.05). Using 50 μM H 2 O 2 , we performed time courses and measured OPN mRNA by qRT-PCR and protein by Western blot. OPN mRNA levels significantly increased in response to H 2 O 2 at 8 (70.4%±5.7, p<0.05) and 18 hours (120.2%±5.2, p<0.005). Interestingly, the increases in OPN protein expression in response to H 2 O 2 occurred in an unusual bi-phasic pattern, with significant increases at 6 (96.9%±1.5, p<0.001) and 18 hours (234.0%±3.6, p<0.001), with a return to baseline in between. An increase in OPN mRNA preceded the increase in OPN protein at 18 hours, suggesting transcriptional regulation; however, the acute increase in OPN at 6 hours was not preceded by increased mRNA, suggesting multiple mechanisms of OPN regulation by H 2 O 2 . To determine if the increase in OPN at 6 hours is due to increased mRNA stability or translation, we performed an RNA stability assay. H 2 O 2 stimulation did not alter OPN stability or the rate of OPN RNA degradation, leading us to conclude the increase in OPN expression at 6 hours is due to increased translation. Further studies reveal H 2 O 2 -mediated increases in phosphorylation of 4E-BP1 at the redox-sensitive Ser65 site (89.4%±6.1, p<0.05), allowing for the subsequent release of eukaryotic initiation factor eIF4E and increased phosphorylation at Ser209 (139.2%±3.9, p<0.05), resulting in increased OPN translation. In conclusion, H 2 O 2 enhances OPN expression through acute increases in translation, while long-term increases in OPN occur through increased transcriptional regulation.

Abstract 452: Cyclic Strain Induces Osteopontin Expression in Vascular Smooth Muscle via a Hydrogen Peroxide--Dependent Mechanism

Introduction: Vascular inflammation, a hallmark of hypertension, is associated with increased cyclic strain on the vessel wall. Reactive oxygen species (ROS), such as superoxide and hydrogen peroxide, are known to play an important role in the progression of cardiovascular inflammation. However, the underlying molecular mechanisms of ROS modulation of vascular inflammation through increased cyclic strain remain largely unknown. Objective: In this study, we sought to determine whether cyclical strain induces an increase in osteopontin (OPN), a pro-inflammatory protein, in a hydrogen peroxide dependent manner using an in vitro cell system. Methods: Rat aortic smooth muscle cells were seeded on collagen-I coated, flexible bottomed six-well plates and cyclically stretched at 10% elongation in a biaxial stretch bioreactor. Following stretch, cells were harvested and protein, mRNA, and hydrogen peroxide levels were measured via Western Blotting, quantitative real-time PCR, and Amplex Red assay, respectively. Results: Preliminary results indicate that cyclic strain promotes a 16% ± 6 increase in hydrogen peroxide levels compared to non-stretched cells at 8 hours. In addition, elevated expression of OPN protein was observed with 24 hours of stretch (195% ± 16). Increased OPN mRNA was also observed with 12 hours of stretch (39% ± 15). Finally, OPN expression was blunted when cells were simultaneously stretched for 24 hours with 200U/mL PEG-Catalase (a H2O2 scavenger) suggesting that the stretch induced increase in OPN expression is mediated by hydrogen peroxide (49%±14 decrease in cells stretched with PEG-Catalase versus non- PEG-Catalase treated but stretched cells) Conclusion: These data support that increased cyclical mechanical stretch, as experienced by the vascular wall under hypertensive conditions, increases osteopontin expression, via a hydrogen peroxide-mediated pathway.

Chromatin Remodeling Underlies the Senescence-Associated Secretory Phenotype of Tumor Stromal Fibroblasts That Supports Cancer Progression

Age is a major risk factor for the development of cancer. Senescent fibroblasts, which accumulate with age, secrete protumorigenic factors collectively referred to as the senescence-associated secretory phenotype (SASP). Here, we examined the molecular mechanisms that control SASP activation, focusing on the known SASP factor osteopontin (OPN). We found that expression of the canonical SASP members interleukin (IL)-6 and IL-8, but not OPN, were dependent upon a persistent DNA damage response (DDR) as evidenced by ATM and NF-κB activation. Treatment with several histone deacetylase (HDAC) inhibitors robustly activated SASP in the absence of DNA breaks, suggesting that DDR-dependent SASP activation occurs in response to chromatin remodeling rather than physical breaks in DNA. In the setting of HDAC inhibition, IL-6 and IL-8 expression remained dependent upon ATM and NF-κB, while OPN expression remained independent of these factors. Further analysis revealed that HDAC1 inhibition was sufficient to induce OPN expression, which is interesting given that loss of HDAC1 expression correlates with increased OPN expression within the stromal compartment of invasive breast cancers. Importantly, fibroblasts treated with HDAC inhibitors promoted tumor growth in vivo. Our findings therefore indicate that HDAC modulation plays an important role in stromal cell activation, with important implications for the use of HDAC inhibitors in the treatment of cancer.

Reactive Oxygen Species Regulate Osteopontin Expression in a Murine Model of Postischemic Neovascularization

Previous findings from our laboratory demonstrated that neovascularization was impaired in osteopontin (OPN) knockout animals. However, the mechanisms responsible for the regulation of OPN expression in the setting of ischemia remain undefined. Therefore, we sought to determine whether OPN is upregulated in response to ischemia and hypothesized that hydrogen peroxide (H(2)O(2)) is a critical component of the signaling mechanism by which OPN expression is upregulated in response to ischemia in vivo. To determine whether ischemic injury upregulates OPN, we used a murine model of hindlimb ischemia. Femoral artery ligation in C57BL/6 mice significantly increased OPN expression and H(2)O(2) production. Infusion of C57BL/6 mice with polyethylene glycol-catalase (10 000 U/kg per day) or the use of transgenic mice with smooth muscle cell-specific catalase overexpression blunted ischemia-induced OPN, suggesting ischemia-induced OPN expression is H(2)O(2)-dependent. Decreased H(2)O(2)-mediated OPN blunted reperfusion and collateral formation in vivo. In contrast, the overexpression of OPN using lentivirus restored neovascularization. Scavenging H(2)O(2) blocks ischemia-induced OPN expression, providing evidence that ischemia-induced OPN expression is H(2)O(2) dependent. Decreased OPN expression impaired neovascularization, whereas overexpression of OPN increased angiogenesis, supporting our hypothesis that OPN is a critical mediator of postischemic neovascularization and a potential novel therapeutic target for inducing new vessel growth.

Expression and function of osteopontin in vascular adventitial fibroblasts and pathological vascular remodeling

Objectives: Osteopontin (OPN) is known to play important role in various diseases including vascular disorders. However, little is known about its expression and function in vascular adventitial fibroblasts. Adventitial fibroblasts have been shown to play a key role in pathological vascular remodeling associating with various vascular disorders. In this study, activation of OPN and its biological functions was investigated. Methods and results: Angiotensin II and aldosterone increased OPN expression in adventitial fibroblasts in a time- and concentration-dependent manner.

Expression and Function of Osteopontin in Vascular Adventitial Fibroblasts and Pathological Vascular Remodeling

Osteopontin is known to play important roles in various diseases including vascular disorders. However, little is known about its expression and function in vascular adventitial fibroblasts. Adventitial fibroblasts have been shown to play a key role in pathological vascular remodeling associating with various vascular disorders. In this study, we measured activation of Osteopontin and its biological functions in cultured adventitial fibroblasts and injured rat carotid injury arteries induced by balloon angioplasty. Our results showed that angiotensin II and aldosterone increased Osteopontin expression in adventitial fibroblasts in a time- and concentration-dependent manner. MAPKs and AP-1 pathways were involved in Osteopontin upregulation. In addition, Adventitial fibroblast migration stimulated by Angiotensin II and aldosterone required OPN expression. Perivascular delivery of antisense oligonucleotide for Osteopontin suppressed neointimal formation post-injury. We concluded that upregulation of Osteopontin expression in adventitial fibroblasts might be important in the pathogenesis of vascular remodeling after arterial injury.

Molecular characterization and expression analysis of osteopontin cDNA from lactating mammary gland in yak (Bos grunniens)

Osteopontin (OPN) is a secreted phosphorylated glycoprotein. It has an important role in mammary gland development and lactation, as well as, is thought to be a potential candidate gene for lactation traits. In the present work, we isolated and characterized a full-length open reading frame (ORF) of yak OPN cDNA from lactating mammary tissue, and examined its expression pattern in mammary gland during different stages of lactation, as well as, the recombinant OPN protein of yak was expressed successfully in E. coli. The sequencing results indicated that the isolated cDNA was 1132-bp in length containing a complete ORF of 837-bp. It encoded a precursor protein of yak OPN consisting of 278 amino acid with a signal peptide of 16 amino acids. Yak OPN has a predicted molecular mass of 29285.975Da and an isoelectric point of 4.245. It had an identity of 65.50-99.16% in cDNA, identity of 52.06-98.56% and similarity of 65.40-98.56% in deduced amino acids with the corresponding sequences of cattle, buffalo, sheep, goat, pig, human, and rabbit. The phylogenetic analysis indicated that yak OPN had the closest evolutionary relationship with that of cattle, and next buffalo. In mammary gland, yak OPN was generally transcribed in a declining pattern from colostrum period to dry period with an apparent increase of OPN expression being present in the late period of lactation compared with peak period of lactation. Western blot analysis indicated that His-tagged yak OPN protein expressed in E. coli could be recognized not only by an anti-His-tag antibody but also by an anti-human OPN antibody. These results from the present work provided a foundation for further insight into the role of OPN gene in yak lactation.

Ghrelin reduces rat myocardial calcification induced by nicotine and vitamin D3 in vivo

Ghrelin, a newly discovered bioactive peptide, initially was identified as a strong stimulant for the release of growth hormone (GH) and that has improved cardiac function in patients suffering from end-stage chronic heart failure. Increasing evidence has demonstrated that ghrelin may have myocardial protective effects. However, the role of ghrelin in the pathogenesis of cardiovascular diseases remains unclear. In this study, an in vivo model of rat myocardial calcification induced by vitamin D3 and nicotine was used to study the possible mechanism in the regulatory action of ghrelin on the calcified myocardium. Calcification increased total Ca2+ content and 45Ca2+ deposition in the myocardium and alkaline phosphatase (ALP) activation in the plasma. Compared with the control group, ghrelin mRNA expression was up-regulated and the myocardium calcium content was significantly increased in vitamin D3 and nicotine-treated rats. Rats were subcutaneously injected with 1 or 10 nmol/kg ghrelin. Rats treated with both low- and high-dose ghrelin decreased total Ca2+ content and 45Ca2+ deposition in cardiac muscle and inhibited ALP activation in the myocardium and plasma, in a concentration-dependent manner. In addition, osteopontin (OPN) mRNA expression significantly decreased and that of endothelin (ET-1) significantly increased with myocardial calcification. Ghrelin treatment increased OPN expression at the mRNA level and reduced ET-1 mRNA expression in a dose-dependent manner. These results indicate that exogenous administration with ghrelin attenuates myocardial calcification induced by nicotine and vitamin D3, and that the possible mechanism is via the ghrelin-induced increase in the OPN mRNA levels and decrease in the ET-1 mRNA expression in the myocardium.

Increased Gastric Osteopontin Expression by Helicobacter pylori Infection can Correlate with More Severe Gastric Inflammation and Intestinal Metaplasia

Osteopontin (OPN) is involved in the gastric cancer progression. The study validated whether OPN expressions correlate with Helicobacter pylori-related chronic gastric inflammation and the precancerous change as intestinal metaplasia (IM). This study included 105 H. pylori-infected patients (63 without and 42 with IM) and 29 H. pylori-negative controls. In each subject, the gastric OPN expression intensity was evaluated by immunohistochemistry, and graded from 0 to 4 for the epithelium, lamina propria, and areas with IM, respectively. For the H. pylori-infected subjects, the gastric inflammation was assessed by the Updated Sydney System. Forty-nine patients received follow-up endoscopy to assess OPN change on gastric mucosa after H. pylori eradication. The in vitro cell-H. pylori coculture were performed to test the cell origin of OPN. The H. pylori-infected patients had higher gastric OPN expression than the noninfected controls (p < .001). For the H. pylori-infected patients, an increased OPN expression correlated with more severe chronic gastric inflammation (p < .001) and the presence of IM (OR: 2.6, 95% CI: 1.15-5.94, p = .02). Within the same gastric bits, lamina propria expressed OPN stronger than epithelium (p < .001), suggesting OPN predominantly originates from inflammatory cells. The in vitro assay confirmed H. pylori stimulate OPN expression in the monocytes, but not in the gastric epithelial cells. After H. pylori eradication, the gastric OPN expression could be decreased only in areas without IM (p < .05). Increased gastric OPN expression by H. pylori infection can correlate with a more severe gastric inflammation and the presence of IM.

Abstract 4188: Association of HOX gene expression with osteopontin in ovarian cancer: Implications for biomarker development

Abstract Ovarian cancer is characterized by poor early detection and serves as an excellent model system to develop potential markers for early diagnosis. Osteopontin is a glycophosphoprotein known to demonstrate multiple functions including mediation of cellular adhesion, suppression of macrophage interleukin production, prevention of angiogenesis, apoptosis, and inhibition of anchorage-dependent growth. Studies of Osteopontin in ovarian cancer have described increased expression and a role as a candidate biomarker. Secretion of Osteopontin into the extra cellular matrix is reported to facilitate metastasis and has been reported to be inhibited by the presence of cytoplasmic Homeobox proteins (HOX). The HOX family of genes encodes transcription factors involved in basic developmental processes and has been linked to oncogenesis. Dysregulation of HOX genes may be an early event in malignant transformation making the HOX gene family appealing for biomarker investigation. In this study we characterize HOX gene expression in malignant tumors of the ovary compared to Osteopontin, a known biomarker for ovarian cancer. Methods: Microarray analysis of mRNA from human ovarian tissues was performed on samples of normal, benign, and malignant ovarian tissues. These samples were analyzed using the Affymetrix Human Genome Focus GeneChip (HG-Focus) microarray to distinguish the differential pattern of mRNA expression between the three types of samples. Immunohistochemistry staining of ovarian tissue samples was utilized to analyze confirmatory protein expression of the microarray findings. Results: Microarray analysis demonstrated up-regulation of HOXB2, HOXB7, and Osteopontin genes in malignant ovarian tumor samples compared to normal ovarian tissue controls. Conversely, HOXC6 was down-regulated in malignant tissue samples. Immunohistochemistry was performed for HOXB2, HOXC6 and Osteopontin on OCT embedded tissues samples. Similarly, increased protein expression was shown for HOXB2 and Osteopontin in malignant samples and increased HOXC6 in non-cancerous samples. Conclusion: Our results demonstrate multiple HOX genes to be up-regulated in ovarian cancer. Increased expression of HOXB2 and HOXB7, correlated with increased Osteopontin expression found in malignant ovarian tissue samples. HOXC6 demonstrated an inverse relationship with Osteopontin in non-cancerous ovarian tissue samples. The association of these HOX genes with Osteopontin expression warrants further investigation into the role of HOX genes as candidate biomarkers for ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4188. doi:10.1158/1538-7445.AM2011-4188

Osteopontin Expression during Early Cerebral Ischemia-Reperfusion in Rats: Enhanced Expression in the Right Cortex Is Suppressed by Acetaminophen

Osteopontin (OPN) is a pleiotropic protein implicated in various inflammatory responses including ischemia-reperfusion (I-R) injury. Two distinct forms of the protein have been identified: an extensively studied secreted form (sOPN) and a less-well-known intracellular form (iOPN). Studies have shown that increased OPN expression parallels the time course of macrophage infiltration into injured tissue, a late event in the development of cerebral infarcts. sOPN has been suggested to promote remodeling of the extracellular matrix in the brain; the function of iOPN may be to facilitate certain signal transduction processes. Here, we studied OPN expression in adult male Sprague-Dawley rats subjected to global forebrain I-R injury. We found iOPN in the cytoplasm of both cortices and the hippocampus, but unexpectedly only the right cortex exhibited a marked increase in the iOPN level after 45 min of reperfusion. Acetaminophen, a drug recently shown to decrease apoptotic incidence, caspase-9 activation, and mitochondrial dysfunction during global I-R, significantly inhibited the increase in iOPN protein in the right cortex, suggesting a role for iOPN in the response to I-R injury in the right cortex.