Prognostic significance of osteopontin expression in human gastric carcinoma

Long noncoding RNA (lncRNA) HOTAIR: Pathogenic roles and therapeutic opportunities in gastric cancer

Gastric cancer is one of the first malignant cancers in the world and a large number of people die every year due to this disease. Many genetic and epigenetic risk factors have been identified that play a major role in gastric cancer. HOTAIR is an effective epigenetic agent known as long noncoding RNA (lncRNA). HOTAIR has been described to have biological functions in biochemical and cellular processes through interactions with many factors, leading to genomic stability, proliferation, survival, invasion, migration, metastasis, and drug resistance. In the present article, we reviewed the prognostic value of the molecular mechanisms underlying the HOTAIR regulation and its function in the development of Gastric Cancer, whereas elucidation of HOTAIR–protein and HOTAIR–DNA interactions can be helpful in the identification of cancer processes, leading to the development of potential therapeutic strategies.

CDKN2A Deletion Leading to Hematogenous Metastasis of Human Gastric Carcinoma

Introduction

Somatic copy number deletion (SCND) of CDKN2A gene is the most frequent event in cancer genomes. Whether CDKN2A SCND drives human cancer metastasis is far from clear. Hematogenous metastasis is the main reason of human gastric carcinoma (GC) death. Thus, prediction GC metastasis is eagerly awaited.

Method

GC patients (n=408) enrolled in both a cross-sectional and a prospective cohorts were analysed. CDKN2A SCND was detected with a quantitative PCR assay (P16-Light). Association of CDKN2A SCND and GC metastasis was evaluated. Effect of CDKN2A SCND by CRISPR/Cas9 on biological behaviors of cancer cells was also studied.

Results

CDKN2A SCND was detected in 38.9% of GCs from patients (n=234) enrolled in the cross-sectional cohort. Association analysis showed that more CDKN2A SCND was recognized in GCs with hematogenous metastasis than those without (66.7% vs. 35.7%, p=0.014). CDKN2A SCND was detected in 36.8% of baseline pN₀M₀ GCs from patients (n=174) enrolled in the prospective study, the relationship between CDKN2A SCND and hematogenous metastasis throughout the follow-up period (62.7 months in median) was also significant (66.7% vs. 34.6%, p=0.016). Using CDKN2A SCND as a biomarker for predicting hematogenous metastasis of GCs, the prediction sensitivity and specificity were 66.7% and 65.4%. The results of functional experiments indicated that CDKN2A SCND could obviously downregulate P53 expression that consequently inhibited the apoptosis of MGC803 GC and HEK293T cells. This may account for hematogenous metastasis of GCs by CDKN2A SCND.

Conclusion

CDKN2A SCND may drive GC metastasis and could be used as a predictor for hematogenous metastasis of GCs.

EMT-related genes are unlikely to be involved in extracapsular growth of lymph node metastases in gastric cancer

BACKGROUND

In gastric cancer (GC), extracapsular growth (ECG) pattern of lymph node metastases is associated with decreased overall survival rates compared to intracapsular lymph node metastases (ICG). Epithelial-to-mesenchymal transition (EMT) plays a pivotal role in hematogenous metastatic spread. Aim of the present study was to analyze if EMT related genes are involved in the growth pattern of lymph node metastases in GC.

METHODS

Out of our prospective database with 529 patients who underwent surgical resection for GC between 2002 and 2014 forty lymph node positive patients were identified (20 ECG, 20 ICG). The expression of 84 EMT-associated genes were analyzed by RT2 Profiler PCR Array (n = 20). Results were validated by Real-Time PCR (n = 20).

RESULTS

GC with ECG showed differently expressed EMT related genes. GC leading to ECG showed an upregulation of three and downregulation of eleven genes. Those differences, however, could not be confirmed in PCR analysis.

CONCLUSIONS

This study demonstrates that EMT related genes are not responsible for the different growth patterns of lymph node metastases in GC. Further studies are required to evaluate the underlying mechanisms of ECG in GC as it might provide a potential therapeutic target for this subgroup of more aggressive tumors in the future.

HER2 promotes epithelial-mesenchymal transition through regulating osteopontin in gastric cancer

AIMS

HER2 and osteopontin (OPN) are both important biomarkers in gastric cancer (GC). The relationships between them remain to be revealed. The purpose of this study is to explore the role of OPN in epithelial-mesenchymal transition (EMT) in HER2 positive GCs.

METHODS

Nanostring analysis was used to compare the mRNA levels of 730 cancer related genes between paired HER2 3+ and non-3+ areas in GC patients. Immunohistochemistry (IHC) staining was performed to analyze the expression levels of OPN, as well as EMT markers including E-cad, N-cad, twist and vimentin in both areas. To further verify the role of OPN in EMT, the expression levels of OPN and EMT markers, tumor invasion/migration were analyzed after down-regulating HER2 and OPN in GC cell lines MKN-45 and N-87.

RESULTS

Nanostring analysis identified 8 differential expression genes between HER2 3+ and non-3+ areas. Among them, the expression level of OPN was positively correlated with that of HER2. In GC specimens, OPN showed higher expression level in HER2 3+ areas where higher E-cad expression levels and lower N-cad and twist levels were also found. After knocking down OPN and HER2 by siRNA, both cell lines show decreased invasion/migration abilities, along with the down-regulation of the EMT phenotype, supporting by the decrease of E-cad, and the increase of N-cad and twist at both mRNA and protein levels. In addition, HER2 knock-down lead to a dramatic decrease of OPN expression.

CONCLUSIONS

These findings indicate that HER2 may promote EMT via the regulation of OPN in GCs.

Identification of novel hub genes associated with gastric cancer using integrated bioinformatics analysis

Background

Gastric cancer (GC) is one of the most common solid malignant tumors worldwide with a high-recurrence-rate. Identifying the molecular signatures and specific biomarkers of GC might provide novel clues for GC prognosis and targeted therapy.

Methods

Gene expression profiles were obtained from the ArrayExpress and Gene Expression Omnibus database. Differentially expressed genes (DEGs) were picked out by R software. The hub genes were screened by cytohubba plugin. Their prognostic values were assessed by Kaplan–Meier survival analyses and the gene expression profiling interactive analysis (GEPIA). Finally, qRT-PCR in GC tissue samples was established to validate these DEGs.

Results

Total of 295 DEGs were identified between GC and their corresponding normal adjacent tissue samples in E-MTAB-1440, GSE79973, GSE19826, GSE13911, GSE27342, GSE33335 and GSE56807 datasets, including 117 up-regulated and 178 down-regulated genes. Among them, 7 vital upregulated genes (HMMR, SPP1, FN1, CCNB1, CXCL8, MAD2L1 and CCNA2) were selected. Most of them had a significantly worse prognosis except SPP1. Using qRT-PCR, we validated that their transcriptions in our GC tumor tissue were upregulated except SPP1 and FN1, which correlated with tumor relapse and predicts poorer prognosis in GC patients.

Conclusions

We have identified 5 upregulated DEGs (HMMR, CCNB1, CXCL8, MAD2L1, and CCNA2) in GC patients with poor prognosis using integrated bioinformatical methods, which could be potential biomarkers and therapeutic targets for GC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08358-7.

Bioinformatics Analysis of Key Genes and circRNA-miRNA-mRNA Regulatory Network in Gastric Cancer

Gastric cancer (GC) is one of the most common malignancies in the world, with morbidity and mortality ranking second among all cancers. Accumulating evidences indicate that circular RNAs (circRNAs) are closely correlated with tumorigenesis. However, the mechanisms of circRNAs still remain unclear. This study is aimed at determining hub genes and circRNAs and analyzing their potential biological functions in GC. Expression profiles of mRNAs and circRNAs were downloaded from the Gene Expression Omnibus (GEO) data sets of GC and paracancer tissues. Differentially expressed genes (DEGs) and differentially expressed circRNAs (DE-circRNAs) were identified. The target miRNAs of DE-circRNAs and the bidirectional interaction between target miRNAs and DEGs were predicted. Functional analysis was performed, and the protein-protein interaction (PPI) network and the circRNA-miRNA-mRNA network were established. A total of 456 DEGs and 2 DE-circRNAs were identified with 3 mRNA expression profiles and 2 circRNA expression profiles. GO analysis indicated that DEGs were mainly enriched in extracellular matrix and cell adhesion, and KEGG confirmed that DEGs were mainly associated with focal adhesion, the PI3K-Akt signaling pathway, extracellular matrix- (ECM)- receptor interaction, and gastric acid secretion. 15 hub DEGs (BGN, COL1A1, COL1A2, FBN1, FN1, SPARC, SPP1, TIMP1, UBE2C, CCNB1, CD44, CXCL8, COL3A1, COL5A2, and THBS1) were identified from the PPI network. Furthermore, the survival analysis indicate that GC patients with a high expression of the following 9 hub DEGs, namely, BGN, COL1A1, COL1A2, FBN1, FN1, SPARC, SPP1, TIMP1, and UBE2C, had significantly worse overall survival. The circRNA-miRNA-mRNA network was constructed based on 1 circRNA, 15 miRNAs, and 45 DEGs. In addition, the 45 DEGs included 5 hub DEGs. These results suggested that hub DEGs and circRNAs could be implicated in the pathogenesis and development of GC. Our findings provide novel evidence on the circRNA-miRNA-mRNA network and lay the foundation for future research of circRNAs in GC.

Osteopontin accelerates the development and metastasis of bladder cancer via activating JAK1/STAT1 pathway

BACKGROUND

Bladder cancer is the 10th common cancer worldwide. Osteopontin has been found to enhance cell proliferation, metastasis and invasion in various human tumors.

OBJECTIVE

To investigate the roles of osteopontin in bladder cancer.

METHODS

The RNA interference and overexpression of osteopontin were performed in bladder cancer cell lines (T24 and SCaBER). Cell proliferation and apoptosis were measured using CCK-8 assay and flow cytometry, respectively. Cell invasion was determined using transwell assay.

RESULTS

Osteopontin was highly expressed in bladder cancer tissues in comparison with the adjacent normal tissues. Its high expression significantly correlated with high histologic grade, high TNM stage (III and IV) and poor prognosis. For T24 cells with osteopontin interference and SCaBER cells with osteopontin overexpression, cell proliferation was significantly inhibited (3.58-fold vs. 5.62-fold) and enhanced (7.81-fold vs. 5.29-fold), respectively. The apoptosis portion of T24 cells significantly increased from 4.48 to 10.75%, and that of SCaBER cells significantly declined from 7.33 to 4.01%. The invaded T24 and SCaBER cells significantly decreased to 52.0% and increased to 2.0-fold, respectively. Osteopontin overexpression enhanced the expression (1.54-fold and 2.39-fold; 2.33-fold and 2.05-fold) and activation (1.80-fold and 1.96-fold; 2.00-fold and 2.59-fold) of JAK1 and STAT1 in two cell lines of bladder cancer.

CONCLUSION

Osteopontin might enhance proliferation, inhibit apoptosis and accelerate invasion and thus promote the development and metastasis of bladder cancer, and osteopontin's functions might be mediated by activating JAK1/STAT1 signaling pathway.

Prognostic significance of osteopontin expression in gastric cancer: a meta-analysis

BACKGROUND

Accumulated studies have exploited the association between osteopontin (OPN) expression and survival of patients with gastric cancer (GC), however, the results were controversial. Thus, we performed a meta-analysis, aiming to investigate the prognostic role of OPN for GC patients and to explore the association between OPN and clinicalpathological features of GC.

RESULTS

A total of ten studies involving 1775 patients were included in final meta-analysis. Of the included studies, nine were conducted on Asian patients and one was performed on Caucasian patients. Regarding OPN detection, immunohistochemistry (IHC) was used on tissue specimens in eight studies and enzyme linked immunosorbent assay (ELISA) was used on plasma specimens in two studies. The pooled data showed that high OPN expression was correlated with poor OS (HR = 1.59, 95% CI: 1.15-2.22, p = 0.006). Subgroup analyses demonstrated that OPN had enhanced prognostic value for Asian patients (HR = 1.64, 95% CI = 1.11-2.41, p = 0.012) and for patients receiving surgical resection (HR = 1.6, 95% CI = 1.04-2.48, p = 0.034). In addition, the results also showed that elevated OPN expression was associated with lymph node metastasis, TNM stage, depth of invasion, tumor size and distant metastasis in GC.

METHODS

Relevant studies were retrieved through PubMed, Embase and Web of Science. Combined hazard ratio (HR) and 95% confidence interval (CI) were calculated to assess the association between OPN and overall survival (OS). Subgroup analyses and publication bias were also conducted.

CONCLUSIONS

OPN overexpression was correlated with poor OS and clinical features reflecting high aggressiveness in patients with GC. OPN was a promising prognostic biomarker for GC.

Non-invasive detection of bladder cancer via expression-targeted gene delivery

BACKGROUND

Because of the time and expense associated with the procedures and possible distress to the patient, cystoscopy or other imaging techniques are typically not used for bladder cancer detection before symptoms become present. Alternatively, commercial assays for urinary tumor markers exist but are marred by low sensitivity and high cost. There is a need for a simple and sensitive means of tumor detection, such as via the analysis of urine.

METHODS

Plasmids encoding the secretable reporter Gaussia Luciferase (G.LUC), under the control of cmv, cox2 or opn promoters, were delivered via polyethylenimine into bladder tumor cells in culture and into the bladders of mice. Expression profiles of the reporter were recorded, the optimal times for reporter detection were determined and the relationship of reporter expression with tumor size was calculated.

RESULTS

In vitro results showed that both the cox2 and opn promoters can drive significant expression of G.LUC in bladder carcinoma cells in a targeted fashion. In vivo results demonstrated that the cox2 promoter caused expression of G.LUC at detectable levels in the urine, with local signal maxima occurring at 48 and 72 h post-transfection. G.LUC levels in the urine had a 24-h periodicity, with the periodicity partly being the result of an agent secreted by tumor cells that served to mask the luciferase signal.

CONCLUSIONS

Having shown tumor specificity and having been calibrated with respect to circadian expression patterns, the detection system shows great promise for future investigation of tumor presence both in the urinary bladder and other models of cancer.

Three-dimensional combined biomarkers assay could improve diagnostic accuracy for gastric cancer

So far, stomach-specific biomarkers, gastric cancer(GC)-related environmental factors, and cancer-associated biomarkers are three major classes of serological biomarkers with GC warning potential, joint detection of which is expected to increase the diagnosis efficiency. We investigated whether the combination of serum pepsinogens(PGs), IgG anti-Helicobacter pylori (HpAb), and osteopontin (OPN) can be used as a panel for GC diagnose. Serum was collected from 365 GC patients and 729 healthy individuals,furtherly 332 cases and 332 age- and sex-matched controls were selected for the matched analysis. Serum levels were measured by ELISA. Logistic regression and receiver operator characteristic curve (ROC) were used to assess the associations of biomarkers with GC and the discriminative performance of biomarkers for GC. The area under ROC from three-dimensional combination of PGI/II-HpAb-OPN (0.826) was significantly higher than two-dimensional combination of PGI/II-HpAb (0.786, P < 0.001), PGI/II-OPN (0.787, P < 0.001), and OPN-HpAb (0.801, P = 0.006), as well as one-biomarker of PGI/II (0.735, P < 0.001), HpAb (0.737, P < 0.001) and OPN(0.713, P < 0.001), respectively. The combination of PGI/II-HpAb-OPN, yielded a sensitivity of 70.2% and specificity of 78.3% at the predicted probability of 0.493 as the optimal cutoff point. Three-dimensional combined biomarkers assay could improve diagnostic accuracy for gastric cancer.

The prognostic value of osteopontin in limited-stage small cell lung cancer patients and its mechanism

Osteopontin (OPN) is known to be overexpressed in numerous carcinomas. Although abundant OPN has been reported to be correlated with poor survival in non-small cell lung cancer (NSCLC) but their clinical and prognostic significance in SCLC remains unknown. In this study, RNA-sequencing was used to obtain gene expression data in SCLC tissue samples and OPN expression levels were then investigated using qPCR, immunohistochemical and Western blot. We found OPN was one of the most upregulated genes. Besides, the correlation of OPN with tumor clinicopathological characteristics was evaluated and we found OPN was associated with advanced tumor stages. In addition, Kaplan-Meier survival analysis and Cox analyses revealed OPN expression was an independent predictor for overall survival (OS) (P= 0.013) and progression-free survival (PFS) (P=0.008). A high level of OPN was correlated with pT classification and pN classification (P<0.05). Moreover, In vitro experiments, by test the biological function of OPN via colony formation, wound healing, Transwell assays, and western blotting, we found that overexpression of OPN induced cell proliferation, migration, and invasion; down-regulation of OPN inhibited these. Overexpression of OPN stimulates epithelial-mesenchymal transition (EMT) whereas OPN silencing prevents the EMT.

IN CONCLUSION

OPN appears to contribute to the malignant mechanism of SCLC and is a promising and significant prognostic predictor in patients with SCLC. Specific silence of OPN could be a future direction to develop a novel therapeutic strategy for SCLC patients.

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.

Runx3 and Cell Fate Decisions in Pancreas Cancer

The RUNX family transcription factors are critical regulators of development and frequently dysregulated in cancer. RUNX3, the least well characterized of the three family members, has been variously described as a tumor promoter or suppressor, sometimes with conflicting results and opinions in the same cancer and likely reflecting a complex role in oncogenesis. We recently identified RUNX3 expression as a crucial determinant of the predilection for pancreatic ductal adenocarcinoma (PDA) cells to proliferate locally or promulgate throughout the body. High RUNX3 expression induces the production and secretion of soluble factors that support metastatic niche construction and stimulates PDA cells to migrate and invade, while simultaneously suppressing proliferation through increased expression of cell cycle regulators such as CDKN1A/p21 ^WAF1/CIP1 . RUNX3 expression and function are coordinated by numerous transcriptional and post-translational inputs, and interactions with diverse cofactors influence whether the resulting RUNX3 complexes enact tumor suppressive or tumor promoting programs. Understanding these exquisitely context-dependent tumor cell behaviors has the potential to inform clinical decision-making including the most appropriate timing and sequencing of local vs. systemic therapies.

Signature of cytokines and angiogenic factors (CAFs) defines a clinically distinct subgroup of gastric cancer

BACKGROUND

Little is known about cytokine and angiogenic factors (CAFs) in gastric cancer (GC) in terms of tumor classification and prognostic value. Here, we aimed to correlate CAF signature with overall survival (OS) in GC.

METHODS

We measured pretreatment serum levels of 52 kinds of CAFs in 68 GC patients who were treated with fluoropyrimidine and platinum combination chemotherapy using multiplex bead immunoassays and enzyme-linked immunosorbent assay. We evaluated correlations between CAF levels and pathological features and OS.

RESULTS

Three distinct patient groups were identified: one with high levels of proangiogenic factors, another with high levels of proinflammatory factors, and the other with high levels of both factors. Eleven CAFs [interleukin (IL)-2 receptor-alpha, growth-regulated alpha protein, hepatocyte growth factor, macrophage colony-stimulating factor, stromal cell-derived factor, IL-6, IL-8, IL-10, interferon-gamma, vascular endothelial growth factor, and osteopontin] were independently correlated with poor OS. Clustering analysis of these 11 CAFs revealed distinct high and low 11-CAF signature groups. High 11-CAF signature was associated with shorter OS (10.1 vs. 17.9 months, p = 0.026) along with poor performance status, and the presence of signet ring cell components in multivariate analysis of OS (HR 1.76, p = 0.029). The patients' traditional clinicopathological characteristics were not significantly different between the high and low 11-CAF signature groups.

CONCLUSION

Serum CAF profiling differentiated GC patient groups. A high 11-CAF signature could identify GC patients with a poor prognosis when treated with standard chemotherapy who need urgent new treatment strategies.

Osteopontin, E-cadherin, and β-catenin expression as prognostic biomarkers in patients with radically resected gastric cancer

A correlation between osteopontin, E-cadherin, β-catenin, and cyclooxygenase 2 overexpression and poor clinicopathological features and prognosis has been previously suggested in gastric cancer. This translational study was aimed at assessing the correlation of these immunohistochemical biomarkers with outcome in patients with radically resected gastric cancer. We analyzed osteopontin, E-cadherin, β-catenin, and cyclooxygenase 2 expression by immunohistochemistry in 346 primary gastric tumor tissue samples from patients enrolled in the ITACA-S trial. This phase III study randomized patients with radically resected gastric cancer to receive adjuvant chemotherapy with either 5-fluorouracil and leucovorin or a sequential regimen of infusional 5-fluorouracil and leucovorin plus irinotecan followed by cisplatin and docetaxel. High expression of osteopontin was correlated with high histological grade, diffuse histotype, and peritoneal relapse, but not with TNM stage. Moreover, osteopontin overexpression was associated with higher risk of tumor recurrence and metastases, and was an independent prognostic factor for both relapse-free and overall survival of gastric cancer patients following adjuvant chemotherapy. Abnormal E-cadherin expression and abnormal β-catenin expression were correlated with more advanced disease stage, and as a consequence, with poor outcome. Our results suggest that osteopontin overexpression is a valuable independent predictor of tumor recurrence and survival in patients with radically resected gastric cancer.

Down-regulation of osteopontin mediates a novel mechanism underlying the cytostatic activity of TGF-β

PURPOSE

Loss of a cytostatic response to TGF-β has been implicated in multiple hyper-proliferative disorders, including cancer. Although several key genes involved in the cytostatic activity of TGF-β have in the past been identified, its exact mode of action is yet to be elucidated. A comprehensive understanding of the mechanisms underlying the cytostatic activity of TGF-β may open up new avenues for the development of therapeutic strategies.

METHODS

Quantitative real-time RT-PCR was used to assess osteopontin (OPN) gene expression in human hepatoma-derived Huh-7 and lung adenocarcinoma-derived A549 cells. Reporter assays using an OPN promoter-luciferase construct and its mutated counterparts were performed to assess its transcriptional activity. Binding of Smad4 to the OPN gene promoter was investigated using chromatin immunoprecipitation (CHIP). The putative role of Smad4 in OPN gene expression down-regulation was also assessed using a shRNA-mediated knockdown strategy. The anti-proliferative effect of TGF-β on different cancer-derived cell lines was determined using the cell proliferation reagent WST-1.

RESULTS

We found that the OPN expression levels dose-dependently decreased in TGF-β-treated Huh-7 and A549 cells. Our reporter assays indicated that this TGF-β-induced repression occurred at the transcriptional level, and could largely be abrogated by disruption of an element (TIE2) similar to the TGF-β inhibitory element found in other TGF-β-repressed genes. Our CHIP assay revealed that the Smad protein complex specifically binds to the OPN gene promoter, and that the TGF-β-mediated inhibition of OPN was lost upon shRNA-mediated knockdown of Smad4. Moreover, we found that the deregulation of OPN gene expression by TGF-β occurred concomitantly with loss of the TGF-β anti-proliferative response, whereas a neutralizing anti-OPN antibody partially restored this response.

CONCLUSIONS

Our results indicate that the OPN gene is a direct target of Smad-mediated TGF-β signaling, implying that OPN expression inhibition serves as a novel mechanism underlying the cytostatic activity of TGF-β.

Ablation of osteopontin suppresses N-methyl-N-nitrosourea and Helicobacter pylori-induced gastric cancer development in mice

Several clinical studies have reported increased expression of osteopontin (OPN) in various types of human cancer, including gastric cancer. However, the precise mechanisms underlying tumor development remain unclear. In the present study, we investigated the pathogenic roles of OPN in Helicobacter pylori-induced gastric cancer development. Wild-type (WT) and OPN knockout (KO) mice were treated with N-methyl-N-nitrosourea (MNU) and infected with H.pylori. Mice were killed 50 weeks after treatment, and stomach tissues were assessed by histopathological examination, immunohistochemistry, quantitative real-time RT-PCR and western blotting. To clarify the carcinogenic effects of OPN, we also conducted an in vitro study using AGS human gastric cancer cell line and THP-1 human monocytic cell line. The overall incidence of gastric tumors was significantly decreased in OPN KO mice compared with WT mice. Apoptotic cell death was significantly enhanced in OPN KO mice and was accompanied by upregulation of signal transducer and activator of transcription 1 (STAT1) and inducible nitric oxide synthase (iNOS). In vitro study, OPN suppression also caused STAT1 upregulation and iNOS overexpression in AGS and THP-1 cells, which resulted in apoptosis of AGS cells. In addition, a negative correlation was clearly identified between expression of OPN and iNOS in human gastric cancer tissues. Our data demonstrate that loss of OPN decreases H.pylori-induced gastric carcinogenesis by suppressing proinflammatory immune response and augmenting STAT1 and iNOS-mediated apoptosis of gastric epithelial cells. An important implication of these findings is that OPN actually contributes to the development of gastric cancer.

High specific detection of osteopontin using a three-dimensional copolymer layer support based on electrochemical impedance spectroscopy

Tumor marker detection is essential for the therapy efficiency of early stage tumors and the evaluation of disease progression. Osteopontin (OPN) is supposed to be closely related to several kinds of tumors. In the present study, we describe a label-free electrochemical detection of OPN based on a specific reaction between OPN and its relevant antibody. An artificial three-dimensional (3D) scaffold structure consisting of 11-mercaptoundecanoic acid/6-mercapto-1-hexanol, dextran amino and synthetic peptides was designed as a substrate for the immobilization of the antibody. This substrate was characterized using cyclic voltammetry, atomic force microscopy and Fourier transform infrared reflection spectroscopy. Antibody immobilization and OPN detection were conducted using electrochemical impedance spectroscopy (EIS). The low limit of detection was 0.17 nM. The concentration of cancer risk (5.77 nM) can be selectively detected with a high EIS signal. The fabricated 3D OPN sensor is proposed for application in clinical analysis.

Serum OPN expression for identification of gastric cancer and atrophic gastritis and its influencing factors

Background

Most studies have found that osteopontin (OPN) expression level is related to the poor prognosis of gastric cancer. However, few studies have examined the relationship between OPN expression and gastric precancerous diseases, and the potential role of OPN in the formation and development of GC. We investigated the relationships between serum OPN levels and the risks of gastric cancer (GC) and its precancerous disease, to explore the diagnostic efficacy of serum OPN level for GC and atrophic gastritis and its influencing factors.

Methods

A total of 1,452 patients were enrolled, including 609 with mild superficial gastritis (SG), 594 with atrophic gastritis (AG) and 249 with GC. The levels of serum OPN and serum Helicobacter pylori IgG antibody were detected by enzyme-linked immunosorbent assay.

Results

Serum OPN levels increased from mild SG (1.99±1.91 ng/ml) to AG (2.37±2.27 ng/ml) to GC (5.94±4.52 ng/ml) (P≤0.002), along with increasing severity of gastric disease. OPN levels were significantly higher in patients with GC compared with the non-cancer population (2.17±2.10, P<0.0001). Serum OPN level was positively correlated with age and was higher in men than women, but was not correlated with H. pylori infection status. The area under the receiver operating characteristic curve was 0.805, the optimal cutoff was 2.56 ng/ml and the sensitivity and specificity were 74.3% and 71.8%, respectively, for the ability of serum OPN to discriminate GC.

Conclusions

Serum OPN expression was closely related to the risks of GC and AG, and it might be a useful marker for the discrimination of GC. OPN level was positively correlated with age and male sex, but was not affected by H. pylori infection, and it was promoted by smoking and drinking, in patients with mild SG.

Genetic association of osteopontin (OPN) and its receptor CD44 genes with susceptibility to Chinese gastric cancer patients

PURPOSE

(1) To investigate associations between single nucleotide polymorphisms (SNPs) in osteopontin (OPN) and its receptor-cluster of differentiation 44 (CD44) genes and gastric cancer susceptibility. (2) To explore the correlation of OPN and CD44 expression of gastric cancer.

METHODS

We detected 26 SNPs of the genes in gastric cancer patients from the Chinese Han population by Sequenom technique and performed expression of OPN in combination with CD44 in 243 tissues samples of the cases by tissue microarray and immunohistochemistry (IHC).

RESULTS

We found that the minor alleles of OPN rs4754C>T and OPN rs9138C>A remained strongly associated with decreased gastric cancer risk (P = 1.53 × 10(-4), odds ratio (OR) 0.642, 95 % confidence interval (CI) 0.511-0.808 and P = 1.59 × 10(-4), OR 0.642, 95 %CI 0.510-0.809). OPN variant rs1126772A>G and CD44 variant rs353639A>C significantly contributed to elevated risk of gastric cancer (P = 0.042, OR 1.279, 95 % CI 1.008-1.622 and P = 0.047, OR 1.334, 95 % CI 1.003-1.772). Haplotypes of OPN and CD44 variants significantly influenced risk of gastric cancer. Clinical data indicated that rs4754 and rs9138 of OPN were significantly associated with smoking (P = 0.029, OR 0.343, 95 % CI 0.127-0.926 and P = 0.029, OR 0.343, 95 %CI 0.127-0.926) and OPN rs1126772 revealed associations with tumor-node-metastasis (TNM) stage (P = 0.025, OR 1.765, 95 % CI 1.073-2.905) and tumor differentiation (P = 0.031, OR 1.722, 95 % CI 1.049-2.825). OPN expression was observed in 133 of the 243 cases (54.7 %) by IHC and was correlated with serosa invasion (P = 0.013), TNM stage (P = 0.003) and lymph node metastasis (P = 0.002). CD44 expression was found in 92 of the 243 cases (37.9 %) and was associated with tumor size (P = 0.005) and lymph node metastasis (P = 0.023), respectively. The OPN expression displayed a positive association with CD44 (P = 0.01, r s = 0.164).

CONCLUSIONS

We found that the polymorphisms rs4754, rs9138 and rs1126772 of OPN gene and rs353639 of CD44 gene were significantly associated with gastric cancer. Our IHC data indicated that interaction of OPN and CD44 protein would promote progression and metastasis of gastric cancer.

Osteopontin promotes the progression of gastric cancer through the NF-κB pathway regulated by the MAPK and PI3K

To elucidate the biological functions of osteopontin (OPN) in gastric tumors and to better understand the molecular events of OPN responsible for the malignancy, the present studies were performed. Growth curve, apoptosis assay, invasion assay and migration assay revealed that OPN status significantly affected proliferation, apoptosis, invasion and migration in gastric cancer cell lines. In mouse xenograft models of human gastric cancer, OPN silencing significantly inhibited tumor growth and the incidence of metastasis compared with non-silenced control. Mechanistic investigations revealed that OPN silencing inhibited the mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K) and phosphoinositide 3-kinase (NF-κB) pathways, and OPN-mediated NF-κB activity was reduced in the presence of MAPK or PI3K inhibitor. Our findings also indicated that OPN through the NF-κB pathway promotes the expression of matrix metalloproteinase 2 (MMP-2), MMP-9 and urokinase-type plasminogen activator (uPA), the activation of MMP-2 and MMP-9, and the inhibition of caspase-3. Taken together, our results reveal that OPN promotes the progression of gastric cancer through the NF-κB pathway, which is regulated by the MAPK and PI3K pathways and leads to MMP-2, MMP-9 and uPA activation and caspase-3 inhibition. These findings identify OPN as a novel oncogene in gastric cancer and suggest that OPN is an attractive therapeutic target for this aggressive malignancy.

Anti-inflammatory properties of kaempferol via its inhibition of aldosterone signaling and aldosterone-induced gene expression

Osteopontin (OPN), also called cytokine Eta-1, is a pro-inflammatory cytokine. Recent studies have shown that aldosterone increases OPN gene expression in endothelial cells. As a flavonoid compound, kaempferol has potent anti-inflammatory properties, but whether kaempferol regulates aldosterone signaling and aldosterone-induced gene expression is still unknown. Human umbilical vein endothelial cells (HUVECs) were pretreated with kaempferol (0, 1, 3, or 10 μmol/L) for 1 h prior to exposure to aldosterone (10−6 mol/L) for 24 h. Aldosterone induced generation of reactive oxygen species; OPN and cluster of differentiation 44 gene expression; phospho-p38 MAPK and NF-κB binding activity. The effect of aldosterone was abrogated by kaempferol and spironolactone (10−6 mol/L). The present results suggest that kaempferol exerts its anti-inflammatory properties via its inhibition of aldosterone signaling and aldosterone-induced gene expression in HUVECs.

Biomarkers for predicting future metastasis of human gastrointestinal tumors

The recent advances in surgery and radiation therapy have significantly improved the prognosis of patients with primary cancer, and the major challenge of cancer treatment now is metastatic disease development. The 5-year survival rate of cancer patients who have distant metastasis at diagnosis is extremely low, suggesting that prediction and early detection of metastasis would definitely improve their prognosis because suitable patient therapeutic management and treatment strategy can be provided. Cancer cells from a primary site give rise to a metastatic tumor via a number of steps which require the involvement and altered expression of many regulators. These regulators may serve as biomarkers for predicting metastasis. Over the past few years, numerous regulators have been found correlating with metastasis. In this review, we summarize the findings of a number of potential biomarkers that are involved in cadherin-catenin interaction, integrin signaling, PI3K/Akt/mTOR signaling and cancer stem cell identification in gastrointestinal cancers. We will also discuss how certain biomarkers are associated with the tumor microenvironment that favors cancer metastasis.

Expression of orphan nuclear receptor NR4A2 in gastric cancer cells confers chemoresistance and predicts an unfavorable postoperative survival of gastric cancer patients with chemotherapy

BACKGROUND

NR4A2, an orphan nuclear receptor essential in the generation of dopaminergic neurons, has been recently linked to inflammation and cancer. This study sought to identify the role of NR4A2 on chemoresistance and postoperative prognosis of gastric cancer (GC).

METHODS

NR4A2 was transfected into GC cells to investigate its effects on chemoresistance to 5-fluorouracil and the tumorigenicity in nude mice. This study also investigated prostaglandin E2 (PGE2 )-induced NR4A2 expression and its effect on chemoresistance. Surgical specimens from patients with stage I through III GC were examined immunohistochemically for NR4A2 expression. Median follow-up time was 76 months for 245 patients.

RESULTS

Ectopic expression of NR4A2 significantly increased the chemoresistance and attenuated 5-fluorouracil-induced apoptosis. Transient treatment of GC cells with PGE2 significantly upregulated NR4A2 expression via the protein kinase A pathway and increased the chemoresistance. Ectopic expression of NR4A2 significantly increased the tumorigenicity. In clinical samples, NR4A2 was preferentially expressed in lymphocytes and epithelial cytoplasm in adjacent mucosa. High expression of NR4A2 (immunoreactive score ≥ 3) in cancer cells significantly predicted an unfavorable postoperative disease-specific survival of patients with stage I to III GC (P = .011), especially for those who received 5-fluorouracil-based chemotherapy (P = .016). This effect was not found in those without the chemotherapy. In multivariate Cox analyses, age, TNM (tumor/node/metastasis) stage, and high NR4A2 expression significantly predicted an unfavorable postoperative survival.

CONCLUSIONS

High NR4A2 expression in GC cells confers chemoresistance, attenuates 5-fluorouracil-induced apoptosis, and predicts an unfavorable survival, especially for those who received chemotherapy. NR4A2 might serve as a prognostic and predictive factor and therapeutic target for patients with GC. Cancer 2013;119:3436-3445.. © 2013 American Cancer Society.

Osteopontin as potential biomarker and therapeutic target in gastric and liver cancers

Gastric cancer and liver cancer are among the most common malignancies and the leading causes of death worldwide, due to late detection and high recurrence rates. Today, these cancers have a heavy socioeconomic burden, for which a full understanding of their pathophysiological features is warranted to search for promising biomarkers and therapeutic targets. Osteopontin (OPN) is overexpressed in most patients with gastric and liver cancers. Over the past decade, emerging evidence has revealed a correlation of OPN level and clinicopathological features and prognosis in gastric and liver cancers, indicating its potential as an independent prognostic indicator in such patients. Functional studies have verified the potential of OPN knockdown as a therapeutic approach in vitro and in vivo. Furthermore, OPN mediates multifaceted roles in the interaction between cancer cells and the tumor microenvironment, in which many details need further exploration. OPN signaling results in various functions, including prevention of apoptosis, modulation of angiogenesis, malfunction of tumor-associated macrophages, degradation of extracellular matrix, activation of phosphoinositide 3-kinase-Akt and nuclear factor-κB pathways, which lead to tumor formation and progression, particularly in gastric and liver cancers. This editorial aims to review recent findings on alteration in OPN expression and its clinicopathological associations with tumor progression, its potential as a therapeutic target, and putative mechanisms in gastric and liver cancers. Better understanding of the implications of OPN in tumorigenesis might facilitate development of therapeutic regimens to benefit patients with these deadly malignancies.

The association of osteopontin and LMX1A expression with World Health Organization grade in meningiomas and gliomas

AIMS

Osteopontin (OPN) and LIM homeobox transcription factor 1, alpha (LMX1A) are important factors related to tumour progression, invasion and metastasis in human cancers. The aim of this study was to test the hypothesis that expression of OPN and of LMX1A correlate with the World Health Organization (WHO) grading system of primary brain tumours.

METHODS AND RESULTS

Immunohistochemical analyses of OPN and LMX1A expression were performed in 139 cases of brain tumour, including 65 meningiomas, 71 gliomas, and three central neurocytomas. More than 90% of WHO grade I meningiomas showed negative or weak staining for OPN and LMX1A. However, among all WHO grade II and III meningiomas, 100% and 66.7% showed moderate or strong staining for OPN and LMX1A, respectively. Similarly, higher percentages of WHO grade I and II gliomas than of WHO grade III and IV gliomas showed negative or weak staining for OPN. A higher intensity of immunoreactivity for LMX1A correlated with more advanced grade in WHO grade I-III gliomas, but not in WHO grade IV tumours.

CONCLUSIONS

Higher immunostaining intensity for OPN and LMX1A correlated with WHO grades for meningiomas and some gliomas. Contrary to our expectations, LMX1A staining in WHO grade IV gliomas was shown to be weaker than in WHO grade III tumours.

Osteopontin is overexpressed in colorectal carcinoma and is correlated with P53 by immunohistochemistry

Osteopontin (OPN), a secreted phosphorylated glycoprotein, has been found to be involved in carcinogenesis, progression and metastasis of several types of cancers. The aim of the present study was to investigate the immunohistochemical expression of OPN in colorectal carcinoma (CRC) and its relationship with clinicopathological parameters and P53. Expression of OPN, Ki-67 and TP53 was detected in 77 cases of CRC by immunohistochemistry and the correlation of the expression of OPN with clinicopathological features, Ki-67 and P53 staining was investigated. Thirty-eight cases (49.4%) of CRC demonstrated OPN overexpression. Overexpression of OPN was associated with lymph node metastasis (P=0.025) and Dukes' stages (P=0.031), but not with gender, histological differentiation, depth of tumor invasion, TNM stages or Ki-67 index. The correlation between expression of OPN and TP53 was statistically significant (P=0.030). In conclusion, OPN is overexpressed in CRC, and plays a role in tumor progression and metastasis, which is possibly regulated by P53.

Increased gastric osteopontin expression by Helicobacter pylori Infection can correlate with more severe gastric inflammation and intestinal metaplasia

BACKGROUND

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).

METHODS

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.

RESULTS

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).

CONCLUSIONS

Increased gastric OPN expression by H. pylori infection can correlate with a more severe gastric inflammation and the presence of IM.

The potential of osteopontin as a therapeutic target for human colorectal cancer

OBJECTIVE

Osteopontin (OPN), a phosphorylated glycoprotein, is involved in tumor progression and metastasis. Previously, we have reported that high OPN mRNA expression level possessed clinicopathological or prognostic significance in human colorectal cancer (CRC). The aim of this study is to investigate whether OPN can serve as a novel molecular target for CRC therapy.

MATERIAL AND METHODS

Western Blot assay was performed to detect the expression of OPN protein in 18 CRC and corresponding nontumor colon tissue samples. RNA interference (RNAi) was employed to knockdown endogenous OPN expression in CRC cell line (LoVo). MTT, colony formation, and tumorigenicity assays were performed to analyze the effect of OPN downregulation on the in vitro and in vivo proliferation of CRC cells. Wound healing and Matrigel invasion assays were performed to analyze the effect of OPN downregulation on migration and invasion of CRC cells. A clonogenic cell survival assay after radiation was performed to analyze the effect of OPN downregulation on the radiosensitivity of CRC cells.

RESULTS

The relative level of OPN protein expression in CRC tissues was significantly higher than that in corresponding nontumor colon tissues (P < 0.05). We found that RNAi-mediated OPN downregulation could inhibit not only in vitro proliferation but also in vivo tumorigenicity of CRC cells. In addition, OPN downregulation could suppress in vitro invasion capacity and enhance in vitro radiosensitivity of CRC cells, which might be associated with decreased levels of MMP-2 and -9 expression.

CONCLUSION

RNAi-targeting OPN could inhibit proliferation, invasion and enhance radiosensitivity of human CRC cells. Therefore, OPN could serve as a novel molecular target for gene therapy of CRC.

Pulmonary tumor thrombotic microangiopathy induced by gastric carcinoma: morphometric and immunohistochemical analysis of six autopsy cases

Background

Pulmonary tumor thrombotic microangiopathy (PTTM) has been known as a rare and serious cancer-related pulmonary complication. However, the pathogenesis and pathophysiology of this debilitating condition still remains obscure and no effective management was recommended. The present study aims to elucidate the pathophysiology of PTTM.

Methods

Autopsy records were searched to extract cases of pulmonary tumor embolism induced by metastasis of gastric carcinoma in the Toho University Omori Medical Center from 2000 to 2006. And then, tissue sections of extracted cases were prepared for not only light microscopic observation but morphometric analysis with the use of selected PTTM cases.

Results

Six autopsies involved PTTM and clinicopathological data of them were summarized. There was a significant negative association between pulmonary arterial diameter and stenosis rate in four cases. Although all cases showed an increase of stenosis rate to some degree, the degree of stenosis rate varied from case to case. Significant differences were found for average stenosis rate between the under 100 micrometer group or the 100 to 300 micrometer group and the 300 micrometer group in four cases. However, no significant differences were found for average stenosis rate between the under 100 micrometer group and the 100 to 300 micrometer group in all cases. Meanwhile, all cases showed positive reactivity for tissue factor (TF), five showed positive reactivity for vascular endothelial growth factor (VEGF), and three showed positive reactivity for osteopontin (OPN).

Conclusions

In the present study, we revealed that the degree of luminal narrowing of the pulmonary arteries varied from case to case, and our results suggested that pulmonary hypertension in PTTM occurs in selected cases which have a widespread pulmonary lesion with severe luminal narrowing in the smaller arteries. Furthermore, our immunohistochemical examination indicated that gastric carcinoma indicating PTTM shows a higher TF-positive rate than typical gastric carcinoma. However, it remains still obscuring whether gastric carcinoma indicating PTTM shows a higher VEGF or OPN-positive rate as determined by immunohistochemistry.

Osteopontin is a new target molecule for ovarian clear cell carcinoma therapy

Recent studies have demonstrated overexpression of osteopontin (OPN) in ovarian clear cell carcinoma. Here, we revealed the role of OPN in invasiveness in ovarian clear cell carcinoma. We used immunofluorescence analysis to detect OPN in a total of 160 patient-derived specimens. Ovarian clear cell carcinoma cell lines, RMG-1 and TOV-21G, were used to monitor changes in OPN and integrin levels, and cell invasiveness following treatment with OPN, simvastatin, and transfection with siRNA. Immunofluorescence analysis revealed statistically significant differences among the histological groups, and ovarian clear cell carcinoma expressed a strong OPN signal. The OPN receptors, alpha v and 5, and beta 1 and 3 integrins, were increased after treatment with OPN. Invasion assays indicated that OPN enhanced in vitro extracellular matrix invasion dose-dependently in ovarian clear cell carcinoma. Simvastatin significantly reduced expression of OPN and the integrins, and decreased ECM invasion. RNA interference also suppressed ECM invasion. These results suggest that down- or up-regulation of OPN is involved in carcinoma cell invasion. We thus conclude that OPN regulation could have a crucial role in ovarian clear cell carcinoma therapy.

Osteopontin promotes gastric cancer metastasis by augmenting cell survival and invasion through Akt-mediated HIF-1alpha up-regulation and MMP9 activation

Osteopontin (OPN) is a secreted, integrin-binding matrix phosphorylated glycoprotein. OPN has been shown to facilitate the progression and metastasis of malignancies and has prognostic value in several types of cancer, including gastric cancer. However, the functional mechanism of OPN mediated metastatic growth in gastric cancer remains unclear. Here, using multiple in vitro and in vivo models, we report that OPN strongly promoted the progression and metastasis of gastric cancer. Immunohistochemical staining revealed that OPN, matrix metalloproteinase (MMP)9 and hypoxia-inducible factor (HIF)-1alpha have statistically significant different expression patterns between well- and poorly differentiated tissue samples (P < 0.05). Correlations existed between OPN and MMP9, and between OPN and HIF-1 (r(1) = 0.872, p(1) < 0.01 and r(2) = 0.878, p(2) < 0.01). Furthermore, OPN dramatically increased colony formation and invasion of gastric cancer cells in vitro and promoted tumour growth and metastasis in vivo. In addition, OPN potently protected gastric cancer cells from serum depletion-induced apoptosis. Further study shows that OPN activated phosphoinositide 3-kinase/Akt survival pathway and up-regulated HIF-1alpha via binding to v3 integrins in gastric cancer cells. Moreover, we found that OPN could activate MMP9 and upregulate MMP2. Taken together, our results suggest that the survival-promoting function is crucial for OPN to promote the development of gastric cancer, and HIF-1 and MMP9 may play key roles during this process. Thus, targeting OPN and its related signalling network may develop an effective therapeutic approach for the management of gastric cancer.

The differences between the localizations of MUC1, MUC5AC, MUC6 and osteopontin in quail proventriculus and gizzard may be a reflection of functional differences of stomach parts

Mucins are high molecular weight glycoproteins which constitute the major component of the mucus layer and are produce by many epithelial tissues in vertebrates. Osteopontin (OPN) is an adhesive phosphorylated glycoprotein that is expressed by a broad range of tissues and cells. Although gastric mucins MUC1, MUC5AC, MUC6 and OPN have been widely used in histological studies and in diagnostic pathology in order to diagnose gastric carcinomas, their localizations in the stomach of quail have not yet been studied. In this study, the localizations of MUC1, MUC5AC, MUC6 and OPN in the proventriculus and gizzard of Japanese quail during the post-hatching period were compared at light microscope levels by applying immunohistochemical methods. In all ages studied, the immunoreactivity of MUC5AC was present in the lining epithelium of both folds and superficial proventricular glands in the proventriculus, whereas MUC1, MUC6 and OPN reactivity was found in the oxynticopeptic cells of profound proventricular glands. In addition, some cells in the fold epithelium of the proventriculus showed a positive reaction to OPN. The immunoreactivity of MUC1 in gizzard was different from that of MUC5AC. Although MUC5AC was expressed in the cells of both the surface epithelium and profound glands of the gizzard, MUC1 was only localized in the profound glands of the gizzard. However, MUC6 and OPN immunoreactivity was absent in the gizzard. The results indicated that the differences between the localizations of MUC1, MUC5AC, MUC6 and OPN in quail proventriculus and gizzard may be a reflection of functional differences of stomach parts. Although the biological significances of the expressions of MUC1, MUC5AC, MUC6 and OPN in the quail stomach remains unknown, these notable glycoproteins may be associated with barrier function, host defence, and/or secretion.

Osteopontin expression is an independent adverse prognostic factor in resectable gastrointestinal stromal tumor and its interaction with CD44 promotes tumor proliferation

BACKGROUND

Osteopontin (OPN) is a multifunctional secreted glycophosphoprotein involved in miscellaneous physiologic and pathologic processes and is functionally related to the transmembrane receptor CD44. Although OPN expression has been identified to be associated with poor prognosis in several gastrointestinal malignancies, its expression in gastrointestinal stromal tumor (GIST) has not been thoroughly investigated. This study was designed to evaluate the clinicopathologic significance of OPN expression in patients with resectable GIST.

METHODS

OPN expression was analyzed for its clinicopathologic significance in surgical specimens from 99 patients with resectable GIST by immunohistochemistry. In situ Proximity Ligation Assay was used for examining OPN and CD44 interaction in tumor tissues and GIST cell lines. The in vitro effects of OPN and its interaction with CD44 also were assessed.

RESULTS

Increased OPN expression was a significant poor prognostic factor that independently predicted recurrence and poor disease-free survival in patients with resectable GIST. The interaction of OPN and CD44 was confirmed by their significant correlation in both GIST tumor tissues and cell lines by in situ Proximity Ligation Assay analysis. OPN and its interaction with CD44 were related to increased mitosis and significantly enhanced GIST tumor cell proliferation in vitro.

CONCLUSIONS

Our study identified the clinicopathologic significance and biologic effects of OPN expression in resectable GIST. Increased OPN expression was an independent poor prognostic factor and its interaction with CD44 significantly correlated with increased mitosis as well as in vitro proliferation-promoting effects.

Osteopontin: an effector and an effect of tumor metastasis

Osteopontin (OPN) is a matricellular protein that is produced by multiple tissues in our body and is most abundant in bone. It is also produced by cancer cells and plays a determinative role in the growth, progression and metastasis of cancer. Clinically, OPN has been reported to be upregulated in tumor cells per se; this is also reflected by increased levels of OPN in the circulation. Thus, increased OPN levels the plasma are an effect of tumor growth and progression. Functionally, high OPN levels are determinative of higher incidence of bone metastases in mouse models and are clinically correlated with metastatic bone disease and bone resorption in advanced breast cancer patients. Several research efforts have been made to therapeutically target and inhibit the activities of OPN. In this article we have reviewed OPN in its role as an effector of critical steps in tumor progression and metastasis, with a particular emphasis on its role in facilitating bone metastasis of breast cancer. We have also addressed the role of the host-derived OPN in influencing the malignant behavior of the tumor cells.

Elevated tumor and serum levels of the hypoxia-associated protein osteopontin are associated with prognosis for soft tissue sarcoma patients

BACKGROUND

Osteopontin (OPN) overexpression is correlated with a poor prognosis for tumor patients. However, only a few studies investigated the prognostic impact of expression of OPN in soft tissue sarcomas (STS) yet.

METHODS

This study is based on tumor and serum samples from 93 adult STS patients. We investigated OPN protein levels in serum (n = 86) and tumor tissue (n = 80) by ELISA and OPN mRNA levels in tumor tissue (n = 68) by quantitative real-time PCR.

RESULTS

No correlation was found between OPN levels in serum and tumor tissue. Moreover, an elevated OPN protein level in the serum was significantly associated with clinical parameters such as higher stage (p = 0.004), higher grade (p = 0.003), subtype (p = 0.002) and larger tumor size (p = 0.03). OPN protein levels in the tumor tissue were associated with higher stage (p = 0.06), higher grade (p = 0.003), subtype (p = 0.07) and an increased rate of relapse (p = 0.02). In addition, using a Cox's proportional hazards regression model, we found that an elevated OPN protein level in the serum and tumor tissue extracts is a significant negative prognostic factor for patients with STS. The relative risks of tumor-related death were 2.2 (p < 0.05) and 3.7 (p = 0.01), respectively.

CONCLUSION

Our data suggest OPN protein in serum as well as in tumor tissue extracts is an important prognostic factor for soft tissue sarcoma patients.

Clinical implication and mitotic effect of CD44 cleavage in relation to osteopontin/CD44 interaction and dysregulated cell cycle protein in gastrointestinal stromal tumor

BACKGROUND

CD44 and osteopontin (OPN) are functionally related molecules that, alone or in combination, play miscellaneous biological and pathophysiologic roles. CD44 cleavage, one unique feature of CD44, occurs in human cancers, but its function remains unclear. This study aimed to assess the clinicopathologic significance and mechanism of CD44 cleavage in gastrointestinal stromal tumor (GIST) with respect to OPN and OPN/CD44 interaction.

MATERIALS AND METHODS

CD44 cleavage was evaluated by immunoblotting in 31 primary GIST tumor specimens with paired normal tissues. OPN/CD44 interaction was examined by in situ proximity ligation assay. The associations of CD44 cleavage activity with clinicopathologic parameters, cyclin D1 expression, beta-catenin expression, OPN expression, and OPN/CD44 interaction were analyzed.

RESULTS

CD44 cleavage activity was demonstrated in 87.1% of GIST, in contrast to its absence in normal tissues. Increased CD44 cleavage activity was significantly associated with enhanced mitosis by multivariate analysis, in addition to being related to tumor size, recurrence, high-risk status, and poor survival by univariate analysis. Mitosis was significantly higher in GIST with increased CD44 cleavage activity, which also positively correlated with tumor-specific beta-catenin and cyclin D1 overexpression, indicating a mitotic effect through aberrant cell cycle. Both OPN and OPN/CD44 interactions were significantly associated with CD44 cleavage.

CONCLUSION

Our study demonstrates the clinicopathological significance of CD44 cleavage in GIST. There is a significantly increased mitosis associated with CD44 cleavage in relation to OPN/CD44 interaction and dysregulated cell cycle in GIST.

Gene expression analysis identifies over-expression of CXCL1, SPARC, SPP1, and SULF1 in gastric cancer

To elucidate gene expression signatures associated with gastric carcinogenesis, we performed a genome-wide expression analysis of 46 Finnish and 20 Japanese gastric tissues. Comparative analysis between Finnish and Japanese datasets identified 58 common genes that were differentially expressed between cancerous and non-neoplastic gastric tissues. Twenty-six of these genes were up-regulated in cancer and 32 down-regulated. Of these genes, 64% were also differentially expressed in another unrelated publicly available dataset. The expression levels of four of the up-regulated genes, CXCL1, SPARC, SPP1 and SULF, were further analyzed in 82 gastric tissues using quantitative real-time RT-PCR. This analysis validated the results from the microarray analysis as the expression of these four genes was significantly higher in the cancerous tissue compared with the normal tissue (fold change 3.4-8.9). Over-expression of CXCL1 also positively correlated with improved survival. To conclude, irrespective of the microarray platform or patient population, a common gastric cancer gene expression signature of 58 genes, including CXCL1, SPARC, SPP1, and SULF, was identified. These genes represent potential biomarkers for gastric cancer.

Clinical significance of the upregulated osteopontin mRNA expression in human colorectal cancer

OBJECTIVE

Osteopontin (OPN) is a phosphorylated glycoprotein which is associated with tumor progression, development, and metastasis. Recently, it has been reported that OPN is highly upregulated in a variety of human malignancies. The aim of this study is to investigate the clinical significance of OPN mRNA expression in colorectal cancer (CRC).

MATERIAL AND METHODS

Conventional reverse transcription polymerase chain reaction (RT-PCR) and Western blot assays were performed to detect the expression of OPN mRNA and protein in human CRC cell lines and normal cell line. Real-time quantitative RT-PCR assay was performed to analyze the expression of OPN mRNA in 82 CRC tissue samples and corresponding non-tumor tissues. Immunohistochemistry was also performed to detect the expression of OPN protein in above tissues. Finally, the correlation between the status of OPN mRNA expression and clinicopathological factors and clinical outcome was evaluated.

RESULTS

Compared with normal human intestinal epithelial cell line, human CRC cell lines showed high level of OPN gene expression at both transcriptional and translational levels. Moreover, the results of real-time quantitative RT-PCR and immunohistochemistry showed that the expression levels of OPN mRNA and protein in tumor tissues were significantly higher than those in the corresponding non-tumor tissues (P < 0.001). The expression level of OPN mRNA was significantly correlated with lymph node metastasis, lymphatic or venous invasion, and TNM stage (P = 0.0033, 0.0061, 0.0008, and 0.0012, respectively). Moreover, we also observed that the disease-free and overall survival rates in patients with high OPN mRNA expression were significantly shorter than those in patients with low OPN mRNA expression (P = 0.0047 and 0.0125). Additionally, the status of OPN mRNA expression was an independent prognostic factor for the prognosis of CRC patients (P = 0.008; RR, 2.775; 95% confidence interval, 2.334-3.811).

CONCLUSION

OPN might play an important role in CRC progression and the status of OPN mRNA expression could be a novel prognostic molecular marker for CRC patients.

Osteopontin expression correlates with invasiveness in cervical cancer

AIM

Osteopontin is a secreted, integrin-binding glycophosphoprotein that is overexpressed in many types of cancers and appears to be involved in carcinogenesis and cancer progression. To understand the role of osteopontin in carcinogenesis of cervical cancer, this study was designed to determine whether osteopontin is expressed in cervical cancer and carcinoma in situ (CIS) tissue as well as in normal cervical tissue.

METHODS

The expression of osteopontin was immunohistochemically analysed from 68 normal cervix, 55 CIS and 52 invasive cervical cancer tissues using a paraffin-embedded tissue array. Immunostaining was evaluated by intensity and the percentage of stained cells.

RESULTS

Osteopontin expression in normal, CIS and cervical cancer tissues was two of 68 (2.9%), 43 of 55 (78.2%) and 46 of 52 (88.4%), respectively (P < 0.01). High intensity (strong positive)/high proportion (more than 50%) staining seen in CIS and cervical cancer tissue samples was 45 of 55 (81.8%)/22 of 55 (40.0%) and 50 of 52 (96.2%)/31 of 52 (59.7%), respectively (P = 0.029 and P = 0.054). There was no significant correlation between the immunostaining score and stage and the immunostaining score and survival.

CONCLUSION

Osteopontin may have a potential use as a diagnostic factor for cervical cancer and osteopontin expression is closely correlated with carcinogenesis and invasion of cervical cancer.

Immunohistochemical expression of osteopontin in gastric cancer

BACKGROUND/AIMS

Osteopontin (OPN) is significantly overexpressed in a variety of malignancies. However, little is known concerning the significance of OPN expression in human cancers. Thus, the aim of this study was to determine the relationship between the degree of OPN expression, the proliferative activity of cancer cells, and the clinicopathological findings for surgically resected gastric cancer.

METHODOLOGY

We evaluated the immunohistochemical expression of OPN in 85 specimens of cancer. Additionally, we investigated a cancer cell proliferative index using an anti-MIB-1 antibody and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling staining. Levels of OPN expression in gastric cancers were classified into three groups. To compare the relationship between OPN expression and clinicopathological findings, the features of cancer lesions were classified using the TNM Classification of Malignant Tumors, 6th Edition.

RESULTS

Immunohistochemical examination of OPN expression in gastric cancer revealed diffuse granular staining in the cytoplasm. High OPN expression was observed in 37 of 85 carcinomas. Strong OPN expression was significantly associated with a low apoptotic index, a high proliferative index, depth of invasion, lymphatic invasion, and venous invasion. Pathologically, intestinal type carcinoma showed strong expression of OPN.

CONCLUSIONS

These data suggested that OPN may play an important role in the invasiveness and the progressive nature of gastric cancer.