CXCL9:SPP1 macrophage polarity identifies a network of cellular programs that control human cancers

Tumor microenvironments (TMEs) influence cancer progression but are complex and often differ between patients. Considering that microenvironment variations may reveal rules governing intratumoral cellular programs and disease outcome, we focused on tumor-to-tumor variation to examine 52 head and neck squamous cell carcinomas. We found that macrophage polarity-defined by CXCL9 and SPP1 (CS) expression but not by conventional M1 and M2 markers-had a noticeably strong prognostic association. CS macrophage polarity also identified a highly coordinated network of either pro- or antitumor variables, which involved each tumor-associated cell type and was spatially organized. We extended these findings to other cancer indications. Overall, these results suggest that, despite their complexity, TMEs coordinate coherent responses that control human cancers and for which CS macrophage polarity is a relevant yet simple variable.

Hepatocellular carcinoma originates from hepatocytes and not from the progenitor/biliary compartment

In many organs, including the intestine and skin, cancers originate from cells of the stem or progenitor compartment. Despite its nomenclature, the cellular origin of hepatocellular carcinoma (HCC) remains elusive. In contrast to most organs, the liver lacks a defined stem cell population for organ maintenance. Previous studies suggest that both hepatocytes and facultative progenitor cells within the biliary compartment are capable of generating HCC. As HCCs with a progenitor signature carry a worse prognosis, understanding the origin of HCC is of clinical relevance. Here, we used complementary fate-tracing approaches to label the progenitor/biliary compartment and hepatocytes in murine hepatocarcinogenesis. In genotoxic and genetic models, HCCs arose exclusively from hepatocytes but never from the progenitor/biliary compartment. Cytokeratin 19-, A6- and α-fetoprotein-positive cells within tumors were hepatocyte derived. In summary, hepatocytes represent the cell of origin for HCC in mice, and a progenitor signature does not reflect progenitor origin, but dedifferentiation of hepatocyte-derived tumor cells.

Mesenchymal stem cells cultured on a collagen scaffold: In vitro osteogenic differentiation

OBJECTIVE

Management of periodontal defects has always been a challenge in clinical periodontics. Recently mesenchymal stem cells (MSC) have been proposed for tissue regeneration in periodontal disease and repair of large bone defects. Bone regeneration has to be supported by a scaffold which has to be biocompatible, biodegradable, and able to support cell growth and differentiation. The aim of this study was to evaluate osteogenic differentiation of MSC seeded on a collagen scaffold.

DESIGN

MSC were obtained from adult rat bone marrow, expanded and cultured in plastic dishes or seeded in a collagen scaffold (Gingistat). MSC were induced towards osteogenic differentiation using osteogenic supplements. Cell differentiation and calcium deposits were evaluated by immunoblotting, immunohistochemistry, histochemical techniques, enzymatic activity assay, and SEM-EDX analysis. Biomaterial in vitro degradation was evaluated by measuring mass reduction after incubation in culture medium.

RESULTS

Rat MSC osteogenic differentiation was demonstrated by osteopontin and osteocalcin expression and an increase in alkaline phosphatase activity. MSC were distributed homogeneously in the collagen scaffold. Nodular aggregates and alizarin red stained calcium deposits were observed in MSC induced towards osteogenic differentiation cultured in dishes or seeded in the collagen scaffold. SEM-EDX analysis demonstrated that calcium co-localized with phosphorous. The biomaterial in vitro degraded in 4-5 weeks.

CONCLUSIONS

MSC from bone marrow differentiate towards osteogenic lineage, representing a suitable cell source for bone formation in periodontal regeneration. Gingistat collagen scaffold supports MSC distribution and differentiation, but its short degradation time may be a limitation for a future application in bone tissue regeneration.

Mineralocorticoid receptor antagonist reduces renal injury in rodent models of types 1 and 2 diabetes mellitus

To determine whether mineralocorticoid receptor (MR) activation plays a role in diabetic renal injury and whether this role differs in types 1 and 2 diabetes mellitus, we examined the effect of a MR antagonist on renal injury in rodent models of type 1 (streptozotocin-treated rat) and type 2 (db/db mouse) diabetes. We studied three groups of 8-wk-old, uninephrectomized Wistar rats for 4 wk: diabetic streptozotocin- (55 mg/kg) treated rats (n = 11), diabetic streptozotocin-treated rats receiving the MR antagonist eplerenone (n = 15), and nondiabetic rats (n = 9). In addition, we studied three groups of 8-wk-old mice for 16 wk: diabetic db/db mice (n = 10), diabetic db/db mice treated with eplerenone (n = 8), and nondiabetic, db/+ littermates (n = 11). Diabetic rats and mice developed albuminuria and histopathological evidence of renal injury, including glomerular hypertrophy, mesangial expansion, and tubulointerstitial injury as well as increased renal cortical levels of MR protein, MR mRNA, TGFbeta mRNA, and osteopontin mRNA. All of these changes were significantly reduced by treatment with eplerenone except for the elevated MR levels. The beneficial effects of eplerenone were not attributable to changes in blood pressure or glycemia. In summary, MR expression was increased in kidneys of diabetic rodents, and MR antagonists effectively reduced diabetic renal injury irrespective of the species or specific cause of the diabetes. Thus, these data suggest that MR activation is a critical factor in the early pathogenesis of renal disease in both type 1 and type 2 diabetes mellitus.

Wnt/beta-catenin inhibits dental pulp stem cell differentiation

Dental pulp stem cells (DPSCs) are a unique precursor population isolated from postnatal human dental pulp and have the ability to regenerate a reparative dentin-like complex. Canonical Wnt signaling plays a critical role in tooth development and stem cell self-renewal through beta-catenin. In this study, the regulation of odontoblast-like differentiation of DPSCs by canonical Wnt signaling was examined. DPSCs were stably transduced with canonical Wnt-1 or the active form of beta-catenin, with retrovirus-mediated infection. Northern blot analysis found that Wnt-1 strongly induced the expression of matricellular protein osteopontin, and modestly enhanced the expression of type I collagen in DPSCs. Unexpectedly, Wnt-1 inhibited alkaline phosphatase (ALP) activity and the formation of mineralized nodules in DPSCs. Moreover, over-expression of beta-catenin was also sufficient to suppress the differentiation and mineralization of DPSCs. In conclusion, our results suggest that canonical Wnt signaling negatively regulates the odontoblast-like differentiation of DPSCs.

Altered mineralization of human osteoarthritic osteoblasts is attributable to abnormal type I collagen production

OBJECTIVE

Bone tissue in osteoarthritis (OA) is composed of abundant undermineralized osteoid matrix. The aim of this study was to investigate the mechanisms responsible for this abnormal matrix, using in vitro OA subchondral osteoblasts.

METHODS

Primary normal and OA osteoblasts were prepared from tibial plateaus. Phenotype was determined by alkaline phosphatase activity, and osteocalcin, osteopontin, prostaglandin E2 (PGE2), and transforming growth factor beta1 (TGFbeta1) were assessed by enzyme-linked immunosorbent assay. Expression of COL1A1 and COL1A2 was determined by real-time polymerase chain reaction. The production of type I collagen was determined by the release of its C-terminal propeptide and Western blot analysis. In vitro mineralization was evaluated by alizarin red staining. Inhibition of TGFbeta1 expression was performed using a small interfering RNA technique.

RESULTS

Mineralization of OA osteoblasts was reduced compared with mineralization of normal osteoblasts, even in the presence of bone morphogenetic protein 2 (BMP-2). Alkaline phosphatase and osteocalcin levels were elevated in OA osteoblasts compared with normal osteoblasts, whereas osteopontin levels were similar. The COL1A1-to-COL1A2 messenger RNA ratio was 3-fold higher in OA osteoblasts compared with normal osteoblasts, and the production of collagen by OA osteoblasts was increased. Because TGFbeta1 inhibits BMP-2-dependent mineralization, and because TGFbeta1 levels are approximately 4-fold higher in OA osteoblasts than in normal osteoblasts, inhibiting TGFbeta1 levels in OA osteoblasts corrected the abnormal COL1A1-to-COL1A2 ratio and increased alizarin red staining.

CONCLUSION

Elevated TGFbeta1 levels in OA osteoblasts are responsible, in part, for the abnormal ratio of COL1A1 to COL1A2 and for the abnormal production of mature type I collagen. This abnormal COL1A1-to-COL1A2 ratio generates a matrix that blunts mineralization in OA osteoblasts.

Reduced expression of biomarkers associated with the implantation window in women with endometriosis

OBJECTIVE

To evaluate the expression of biomarkers of implantation, glycodelin A (GdA), osteopontin (OPN), lysophosphatidic acid receptor 3 (LPA3), and HOXA10, in eutopic endometrium of women with and without endometriosis.

DESIGN

Prospective observational study.

SETTING

Clinical research center.

PATIENT(S)

Twenty-four women with endometriosis and 23 healthy volunteers of similar age.

INTERVENTION(S)

Secretory phase endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Expression of immunohistochemical staining intensity and localization of GdA, OPN, LPA3, and HOXA10 in eutopic endometrium.

RESULT(S)

Endometrial GdA expression was significantly reduced in patients after cycle day 22. The endometrium from women with endometriosis also showed decreased expression of OPN in the late secretory phase and LPA3 and HOXA10 expression in the midsecretory and late secretory phases.

CONCLUSION(S)

The decreased expression of these four biomarkers of implantation may indicate impaired endometrial receptivity in patients with endometriosis, providing one explanation for the subfertility observed even in women with few pelvic implants. Because many of these markers are P dependent, these findings suggest the possibility of reduced endometrial P action in this population.

Biomarker discovery for inflammatory bowel disease, using proteomic serum profiling

Crohn's disease and ulcerative colitis known as inflammatory bowel diseases (IBD) are chronic immuno-inflammatory pathologies of the gastrointestinal tract. These diseases are multifactorial, polygenic and of unknown etiology. Clinical presentation is non-specific and diagnosis is based on clinical, endoscopic, radiological and histological criteria. Novel markers are needed to improve early diagnosis and classification of these pathologies. We performed a study with 120 serum samples collected from patients classified in 4 groups (30 Crohn, 30 ulcerative colitis, 30 inflammatory controls and 30 healthy controls) according to accredited criteria. We compared protein sera profiles obtained with a Surface Enhanced Laser Desorption Ionization-Time of Flight-Mass Spectrometer (SELDI-TOF-MS). Data analysis with univariate process and a multivariate statistical method based on multiple decision trees algorithms allowed us to select some potential biomarkers. Four of them were identified by mass spectrometry and antibody based methods. Multivariate analysis generated models that could classify samples with good sensitivity and specificity (minimum 80%) discriminating groups of patients. This analysis was used as a tool to classify peaks according to differences in level on spectra through the four categories of patients. Four biomarkers showing important diagnostic value were purified, identified (PF4, MRP8, FIBA and Hpalpha2) and two of these: PF4 and Hpalpha2 were detected in sera by classical methods. SELDI-TOF-MS technology and use of the multiple decision trees method led to protein biomarker patterns analysis and allowed the selection of potential individual biomarkers. Their downstream identification may reveal to be helpful for IBD classification and etiology understanding.

Bone sialoprotein and osteopontin in bone metastasis of osteotropic cancers

The mechanisms underlying malignant cell metastasis to secondary sites such as bone are complex and no doubt multifactorial. Members of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs) family, particularly bone sialoprotein (BSP) and osteopontin (OPN), exhibit multiple activities known to promote malignant cell proliferation, detachment, invasion, and metastasis of several osteotropic cancers. The expression level of BSP and OPN is elevated in a variety of human cancers, particularly those that metastasize preferentially to the skeleton. Recent studies suggest that the "osteomimicry" of malignant cells is not only conferred by transmembrane receptors bound by BSP and OPN, but includes the "switch" in gene expression repertoire typically expressed in cells of skeletal lineage. Understanding the role of BSP and OPN in tumor progression, altered pathophysiology of bone microenvironment, and tumor metastasis to bone will likely result in development of better diagnostic approaches and therapeutic regimens for osteotropic malignant diseases.

Biochemical characterization of major bone-matrix proteins using nanoscale-size bone samples and proteomics methodology

There is growing evidence supporting the need for a broad scale investigation of the proteins and protein modifications in the organic matrix of bone and the use of these measures to predict fragility fractures. However, limitations in sample availability and high heterogeneity of bone tissue cause unique experimental and/or diagnostic problems. We addressed these by an innovative combination of laser capture microscopy with our newly developed liquid chromatography separation methods, followed by gel electrophoresis and mass spectrometry analysis. Our strategy allows in-depth analysis of very limited amounts of bone material, and thus, can be important to medical sciences, biology, forensic, anthropology, and archaeology. The developed strategy permitted unprecedented biochemical analyses of bone-matrix proteins, including collagen modifications, using nearly nanoscale amounts of exceptionally homogenous bone tissue. Dissection of fully mineralized bone-tissue at such degree of homogeneity has not been achieved before. Application of our strategy established that: (1) collagen in older interstitial bone contains higher levels of an advanced glycation end product pentosidine then younger osteonal tissue, an observation contrary to the published data; (2) the levels of two enzymatic crosslinks (pyridinoline and deoxypiridinoline) were higher in osteonal than interstitial tissue and agreed with data reported by others; (3) younger osteonal bone has higher amount of osteopontin and osteocalcin then older interstitial bone and this has not been shown before. Taken together, these data show that the level of fluorescent crosslinks in collagen and the amount of two major noncollagenous bone matrix proteins differ at the level of osteonal and interstitial tissue. We propose that this may have important implications for bone remodeling processes and bone microdamage formation.

Distribution of SIBLING proteins in the organic and inorganic phases of rat dentin and bone

The SIBLING protein family is a group of non-collagenous proteins (NCPs) that includes dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), and osteopontin (OPN). In the present study, we compared these four proteins in different phases of rat dentin and bone. First, we extracted NCPs in the unmineralized matrices and cellular compartments using guanidium-HCl (G1). Second, we extracted NCPs closely associated with hydroxyapatite using an EDTA solution (E). Last, we extracted the remaining NCPs again with guanidium-HCl (G2). Each fraction of Q-Sepharose ion-exchange chromatography was analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Stains-All stain, and with western immunoblotting. In dentin, the NH(2)-terminal fragment of DSPP and its proteoglycan form were primarily present in the G1 extract, whereas the COOH-terminal fragment of DSPP was present exclusively in the E extract. The processed NH(2)-terminal fragment of DMP1 was present in G1 and E extracts, whereas the COOH-terminal fragment of DMP1 existed mainly in the E extract. Bone sialoprotein was present in all three extracts of dentin and bone, whereas OPN was present only in the G1 and E extracts of bone. The difference in the distribution of the SIBLING proteins between organic and inorganic phases supports the belief that these molecular species play different roles in dentinogenesis and osteogenesis.

KDM6B epigenetically regulates odontogenic differentiation of dental mesenchymal stem cells

Mesenchymal stem cells (MSCs) have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The histone demethylase KDM6B (also known as JMJD3) was shown to play a key role in promoting osteogenic commitment by removing epigenetic marks H3K27me3 from the promoters of osteogenic genes. Whether KDM6B is involved in odontogenic differentiation of dental MSCs, however, is not known. Here, we explored the role of KDM6B in dental MSC fate determination into the odontogenic lineage. Using shRNA-expressing lentivirus, we performed KDM6B knockdown in dental MSCs and observed that KDM6B depletion leads to a significant reduction in alkaline phosphate (ALP) activity and in formation of mineralized nodules assessed by Alizarin Red staining. Additionally, mRNA expression of odontogenic marker gene SP7 (osterix, OSX), as well as extracellular matrix genes BGLAP (osteoclacin, OCN) and SPP1 (osteopontin, OPN), was suppressed by KDM6B depletion. When KDM6B was overexpressed in KDM6B-knockdown MSCs, odontogenic differentiation was restored, further confirming the facilitating role of KDM6B in odontogenic commitment. Mechanistically, KDM6B was recruited to bone morphogenic protein 2 (BMP2) promoters and the subsequent removal of silencing H3K27me3 marks led to the activation of this odontogenic master transcription gene. Taken together, our results demonstrated the critical role of a histone demethylase in the epigenetic regulation of odontogenic differentiation of dental MSCs. KDM6B may present as a potential therapeutic target in the regeneration of tooth structures and the repair of craniofacial defects.

Abnormal bone remodeling process is due to an imbalance in the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin (OPG) axis in patients with solid tumors metastatic to the skeleton

The role of receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin (OPG) system, and osteopontin (OPN) was studied in patients with solid tumors metastatic to the bone in relation to the type of malignancy and the neoplastic burden to the skeleton. Levels of soluble RANKL (sRANKL), OPG and OPN were assessed in 61 patients with breast, lung and prostate cancer with newly-diagnosed metastasis to the bone, in parallel with bone resorption [C-telopeptide of type-I collagen (CTX), tartrate-resistant acid phosphatase-5b (TRACP-5b)] and bone formation markers [bone-alkaline phosphatase (bALP), osteocalcin (OC), and C-terminal propeptide of collagen type-I (CICP)]. Patients had elevated serum levels of sRANKL, OPG, OPN, TRACP-5b, and bALP, and reduced OC levels compared to controls. OPG correlated with the extent of metastatic bone burden. Patients with breast and lung cancer shared increased levels of sRANKL, OPG, and OPN whereas prostate cancer patients had elevated values of OPG and bALP only. These results suggest that patients with solid tumors metastatic to the bone have severe disruption of the sRANKL/OPG axis. Breast and lung cancer seem to exert their osteolytic action through upregulation of the sRANKL/OPG system and OPN, whereas prostate cancer seems to provoke profound elevation of OPG levels only, thus leading to increased osteoblastic activity.

Human osteopontin: Potential clinical applications in cancer (Review)

Human osteopontin (OPN) is a glycosylated phosphoprotein which is expressed in a variety of tissues in the body. In recent years, accumulating evidence has indicated that the aberrant expression of OPN is closely associated with tumourigensis, progression and most prominently with metastasis in several tumour types. In this review, we present the current knowledge on the expression profiles of OPN and its main splice variants in human cancers, as well as the potential implications in patient outcome. We also discuss its putative clinical application as a cancer biomarker and as a therapeutic target.

The association of bovine PPARGC1A and OPN genes with milk composition in two independent Holstein cattle populations

Many studies have reported quantitative trait loci on chromosome 6 that affect milk production traits in dairy cattle. Osteopontin (OPN) and peroxisome proliferator activated receptor gamma coactivator 1 alpha (PPARGC1A) are located in the middle of chromosome 6 about 6 Mb apart, which is approximately 12 cM. The objective of this study was to investigate the association of OPN and PPARGC1A variants with milk production traits in 2 independent Holstein cattle populations: the University of Wisconsin (UW) daughter design and the Cooperative Dairy DNA Repository (CDDR) granddaughter design resource populations. For OPN, 891 cows from the UW resource population were genotyped for the C/T polymorphism reported previously in the CDDR population. Additive effects were significant for fat percentage, protein percentage, and fat yield in the UW resource population. These results are consistent with previous studies that have shown significant association of OPN variants with milk composition traits. The association between PPARC1A variants was investigated in UW and CDDR resource populations using 2 single nucleotide polymorphisms. For the UW resource population, additive effects were significantly increased for protein percentage and decreased for milk yield. Dominance effects were not significant for any of the examined traits. For the CDDR population, PPARGC1A was associated with a significant increase in milk protein percentage and in SCS. Thus, in UW and CDDR populations, PPARGC1A was associated with a significant increase in milk protein percentage in contrast to association results previously reported for the German Holstein population.

Reduction of renal fibrosis as a result of liposome encapsulated clodronate induced macrophage depletion after unilateral ureteral obstruction in rats

BACKGROUND/AIM

Macrophages have been thought to play a role in renal tubulointerstitial fibrosis; recent reports have demonstrated an antifibrotic effect of macrophages in late-stage renal fibrosis. Liposome-encapsulated clodronate (LC) produces a selective and systemic depletion of phagocytic macrophages in vivo. To study the role of initial infiltrating macrophages in renal fibrosis, we compared the effects of pretreatment with LC and a liposome vehicle for control of the severity of renal fibrosis in a unilateral ureteral obstruction (UUO) rat model.

METHODS

One day after a single intravenous injection of LC or liposome vehicle, the rats underwent UUO. Following 1, 5, and 14 days, the kidneys were examined to evaluate macrophage infiltration and renal fibrosis.

RESULTS

LC depleted macrophages systemically and reduced renal fibrosis associated with UUO; this beneficial effect was accompanied by a decrease of transforming growth factor beta mRNA expression. The osteopontin expression was also reduced by pretreatment with LC.

CONCLUSION

Initial interstitial infiltration of macrophages contributes to tubulointerstitial fibrosis in UUO.

Generating neuron-like cells from BM-derived mesenchymal stromal cells in vitro

BACKGROUND

The multipotency of stromal cells has been studied extensively. It has been reported that mesenchymal stromal cells (MSC) are capable of differentiating into cells of multilineage. Different methods and reagents have been used to induce the differentiation of MSC. We investigated the efficacy of different growth factors in inducing MSC differentiation into neurons.

METHODS

MSC from human BM were isolated and cultured in media supplemented with 10% FBS. These cells were identified and later induced to differentiate into neuron-like cells using different neurotrophic factors. Three different growth factors were used, either alone or in combination: brain-derived neurotrophic factor, epidermal growth factor and neural growth factor.

RESULTS

After 10 days of culture, MSC showed neuron-like morphologic changes. Immunostaining showed that these cells expressed markers for neurons (growth-associated protein-43, neuron-specific nuclear protein and neurofilament 200 kDa) and expression of these markers suggested the transition of immature stages to more mature stages of neuron-like cells.

DISCUSSION

Our results show that BM-derived MSC can differentiate not only into target cells of mesodermal origin but also neuron-like cells of ectodermal origin. The findings show that a combination of growth factors is more effective in inducing MSC into neuron-like cells.

Expression of osteopontin, a target gene of de-regulated Wnt signaling, predicts survival in colon cancer

Osteopontin (OPN) is a secreted phosphoprotein, which has been reported to be associated with tumor progression in numerous solid tumors. In a previous transcriptome study on colorectal cancer, we identified the gene OPN among the most strongly up-regulated transcripts. OPN has been suggested as a putative target of Wnt signaling, but the molecular mechanism responsible for its aberrant transcription is not fully understood. We analyzed 13 normal colon tissues, 9 adenomas, 120 primary colon tumors, and 10 liver metastases by quantitative reverse-transcription PCR. OPN expression was strongly elevated in primary colon cancer and liver metastasis, but not in pre-cancerous lesions and UICC stage I tumors. Multivariate analysis established OPN expression as an independent prognostic parameter for overall survival. Moreover, high OPN expression identified a subgroup of patients with bad prognosis. Next, we determined immunohistochemically a correlation of OPN expression with aberrant beta-catenin staining, which is indicative of Wnt activation. Elevated expression of OPN was significantly correlated with increased cytoplasmic and nuclear beta-catenin staining. The in vivo role of Wnt signaling for the expression of OPN was tested in genetically defined mouse models with (Apc(1638N)) or without (pvillin-KRAS(V12G)) Wnt activating mutations. Mutation of the tumor suppressor APC was necessary for upregulation of OPN expression in the murine tumors on transcript and on protein levels. Thus, OPN is a transcriptional target of aberrant Wnt signaling, and OPN expression alone predicts survival in human colon cancer.

Osteopontin combined with CD44, a novel prognostic biomarker for patients with hepatocellular carcinoma undergoing curative resection

BACKGROUND

Osteopontin (OPN) plays important roles in tumor progression and metastasis through binding to CD44 and integrin. The goal of this study was to elucidate the prognostic significance of OPN and CD44 in hepatocellular carcinoma patients.

METHODS

Tumor tissue microarray was used to detect the expression levels of OPN and CD44 in 302 hepatocellular carcinoma patients undergoing curative resection between 1997 and 2000 at our institute. Clinicopathologic data for these patients were investigated. The prognostic effects of OPN and CD44 were evaluated using the Kaplan-Meier method and compared using the log-rank test. The Spearman rank test and Fisher's exact test were applied to demonstrate correlations.

RESULTS

Both OPN and CD44 were independent predictors for overall survival and disease-free survival. When OPN and CD44 were taken into consideration together, the predictive range was extended and the sensitivity was improved, especially for those patients with normal serum alpha-fetoprotein levels. The 8-year overall survival and disease-free survival rates in OPN+ and/or CD44+ patients were 28.2% and 25.6%, respectively, which were significantly lower than those of OPN-CD44- patients (52.1% and 51.6%, respectively).

CONCLUSIONS

OPN combined with CD44 is a promising independent predictor of tumor recurrence and survival in hepatocellular carcinoma patients.

Secreted phosphoprotein 1 (osteopontin) is expressed by stromal macrophages in cyclic and pregnant endometrium of mice, but is induced by estrogen in luminal epithelium during conceptus attachment for implantation

Secreted phosphoprotein 1 (SPP1, osteopontin) is the most highly upregulated extracellular matrix/adhesion molecule/cytokine in the receptive phase human uterus, and Spp1 null mice manifest decreased pregnancy rates during mid-gestation as compared with wild-type counterparts. We hypothesize that Spp1 is required for proliferation, migration, survival, adhesion, and remodeling of cells at the conceptus-maternal interface. Our objective was to define the temporal/spatial distribution and steroid regulation of Spp1 in mouse uterus during estrous cycle and early gestation. In situ hybridization localized Spp1 to luminal epithelium (LE) and immune cells. LE expression was prominent at proestrus, decreased by estrus, and was nearly undetectable at diestrus. During pregnancy, Spp1 mRNA was not detected in LE until day 4.5 (day 1 = vaginal plug). Spp1-expressing immune cells were scattered within the endometrial stroma throughout the estrous cycle and early pregnancy. Immunoreactive Spp1 was prominent at the apical LE surface by day 4.5 of pregnancy and Spp1 protein was also co-localized with subsets of CD45-positive (leukocytes) and F4/80-positive (macrophages) cells. In ovariectomized mice, estrogen, but not progesterone, induced Spp1 mRNA, whereas estrogen plus progesterone did not induce Spp1 in LE. These results establish that estrogen regulates Spp1 in mouse LE and are the first to identify macrophages that produce Spp1 within the peri-implantation endometrium of any species. We suggest that Spp1 at the apical surface of LE provides a mechanism to bridge conceptus to LE during implantation, and that Spp1-positive macrophages within the stroma may be involved in uterine remodeling for conceptus invasion.

Increased osteopontin levels in the cerebrospinal fluid of patients with multiple sclerosis

OBJECTIVE

To determine cerebrospinal fluid levels of osteopontin (OPN), a proinflammatory cytokine that was found to be overexpressed in multiple sclerosis lesions and increased in plasma during relapses and in secondary progressive multiple sclerosis.

DESIGN

Case series. Osteopontin, interleukin 12p40 (IL-12p40), IL-10, and matrix metalloproteinase 9 were measured by enzyme-linked immunosorbent assay by an investigator unaware of the patients' diagnoses.

PATIENTS

Consecutive patients with multiple sclerosis (n = 27), or other inflammatory (n = 11) or non-inflammatory (n = 23) neurological diseases, undergoing lumbar puncture, were investigated.

RESULTS

Osteopontin was significantly elevated in the cerebrospinal fluid of patients with multiple sclerosis (mean [SD], 415 [186] ng/mL) and other inflammatory diseases (563 [411] ng/mL) compared with those with noninflammatory neurological diseases (286 [150] ng/mL). Cerebrospinal fluid OPN levels were slightly higher than plasma OPN levels. Cerebrospinal fluid OPN levels positively correlated with the ability to detect cerebrospinal fluid IL-12p40.

CONCLUSION

Osteopontin in the cerebrospinal fluid may be, in part, of central nervous system origin, and may play an important role in central nervous system inflammation.

Expression and prognostic significance of osteopontin and caspase-3 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) plays an important role in the development, invasion, and metastasis of malignancies. Recently, several studies have reported that OPN enhances chemoresistance in small-cell lung cancer and breast cancer by blocking caspase-9 and caspase-3-dependent cell apoptosis. The aim of this study was to assess the value of OPN and caspase-3 for predicting tumor recurrence after curative resection in hepatocellular carcinoma (HCC) patients. We found that OPN expression increased concordantly with increasing metastatic potential in human HCC cell lines, whereas caspase-3 expression declined. In a tumor tissue microarray immunohistochemical analysis, we found that patients with higher levels of OPN and lower levels of caspase-3 had a significantly poorer prognosis than patients with lower OPN and higher caspase-3 levels. The combination of OPN and caspase-3 expression thus served as an effective prognosticator. These findings suggest that OPN alone or in combination with caspase-3 may act as an independent indicator for HCC patients after curative resection.

Detection of osteopontin on Holstein bull spermatozoa, in cauda epididymal fluid and testis homogenates, and its potential role in bovine fertilization

Osteopontin (OPN) is a secreted extracellular matrix phosphoprotein identified in various tissues and fluids including those of the male and female reproductive tracts. OPN was previously identified as a 55 kDa high fertility marker in Holstein bull seminal plasma, produced by the ampulla and the vesicular gland. The objectives of this study were to characterize OPN on ejaculated and cauda epididymal sperm using immunofluorescence and western blot analysis, and to assess the role of sperm OPN in fertilization. Solubilized sperm membrane proteins from ejaculated and cauda epididymal sperm were separated by 1D SDS-PAGE, transferred to nitrocellulose, and probed with an antibody to bovine milk OPN. A 35 kDa protein was detected by this antibody in both ejaculated and cauda epididymal sperm membranes. Analyses also recognized OPN at 55 and 25 kDa in cauda epididymal fluid and testicular parenchyma homogenates respectively. Immunofluorescent analysis of ejaculated and cauda epididymal sperm showed OPN localization in a well-defined band in the postacrosomal region of the sperm head and also on the midpiece. Results ofin vitrofertilization experiments showed that sperm treated with an antibody to OPN fertilized fewer oocytes than sperm treated with control medium while increasing incidence of polyspermy, suggesting a role of sperm-associated OPN in fertilization and a block to polyspermy. These studies demonstrate that OPN exists at multiple molecular weight forms in the bull reproductive tract and its presence on ejaculated sperm may signal its importance in fertilization by interacting with integrins or other proteins on the oocyte plasma membrane.

Immunohistochemical detection of osteopontin in advanced head-and-neck cancer: Prognostic role and correlation with oxygen electrode measurements, hypoxia-inducible-factor-1α-related markers, and hemoglobin levels

PURPOSE

The tumor-associated glycoprotein osteopontin (OPN) is discussed as a plasma marker of tumor hypoxia. However, the association of immunohistochemical OPN expression in tumor sections with tumor oxygenation parameters (HF5, median pO(2)), the hypoxia-related markers hypoxia-inducible factor-1alpha (HIF-1alpha) and carbonic anhydrase IX (CAIX), or hemoglobin and systemic vascular endothelial growth factor (VEGF) levels has not been investigated.

METHODS AND MATERIALS

Tumor tissue sections of 34 patients with advanced head-and-neck cancer treated with radiotherapy were assessed by immunochemistry for the expression of OPN, HIF-1alpha, and CA IX. Relationship of OPN expression with tumor oxygenation parameters (HF5, median pO(2)), HIF-1alpha and CA IX expression, hemoglobin and serum VEGF level, and clinical parameters was studied.

RESULTS

Bivariate analysis showed a significant correlation of positive OPN staining with low hemoglobin level (p = 0.02), high HIF-1alpha expression (p = 0.02), and high serum vascular endothelial growth factor level (p = 0.02) for advanced head-and-neck cancer. Furthermore, considering the 31 Stage IV patients, the median pO(2) correlated significantly with the OPN expression (p = 0.02). OPN expression alone had only a small impact on prognosis. However, in a univariate Cox proportional hazard regression model, the expression of either OPN or HIF-1alpha or CA IX was associated with a 4.1-fold increased risk of death (p = 0.02) compared with negativity of all three markers.

CONCLUSION

Osteopontin expression detected immunohistochemically is associated with oxygenation parameters in advanced head-and-neck cancer. When the results of OPN, HIF-1alpha, and CA IX immunohistochemistry are combined into a hypoxic profile, a strong and statistically significant impact on overall survival is found.

Effect of combining ACE inhibition with aldosterone blockade on proteinuria and renal damage in experimental nephrosis

Aldosterone has pro-fibrotic properties and is a potential target for additional intervention in patients with chronic renal disease showing resistance to therapy during treatment with angiotensin-converting enzyme inhibitors (ACEi). Combining ACEi and aldosterone receptor blockade (aldoRB) in proteinuric renal disease reduces proteinuria, but effects on proteinuria-induced renal damage are unknown. We studied the effect of ACEi/aldoRB in adriamycin nephrosis (AN). Six weeks after injection of adriamycin in Wistar rats, randomized treatment with vehicle (VEH, n=8), aldoRB (n=12), ACEi (n=10), or a combination of ACEi/aldoRB (n=14) was given for 12 weeks. Healthy rats served as controls (n=6). Renal damage was quantified by markers of tubular injury (osteopontin (OPN) and kidney injury molecule-1 (Kim-1)), pre-fibrotic lesions (alpha-smooth muscle actin (SMA)), interstitial fibrosis (IF), and focal glomerulosclerosis (FGS). In AN animals, proteinuria was increased compared with controls. ACEi and ACEi/aldoRB significantly reduced proteinuria compared with VEH, whereas aldoRB monotherapy was without effect. Blood pressure was reduced in ACEi and ACEi/aldoRB compared with VEH and aldoRB. OPN and Kim-1 were increased in AN animals, but significantly reduced by ACEi/aldoRB. Treatment with ACEi and ACEi/aldoRB prevented an increase of SMA, IF, and FGS. In conclusion, ACEi/aldoRB effectively reduced proteinuria and markers of tubular injury and prevented renal damage in this rat model of chronic proteinuria-induced renal damage.