Osteopontin expression in a group of lymph node negative breast cancer patients

Osteopontin in cancer

Osteopontin (OPN) is a heavily post-translationally modified protein with a molecular weight of 44-70 kDa, depending on the degree of glycosylation. OPN is involved in various biological processes, including bone remodeling, immune response, cell adhesion, migration, and survival. It is essential for controlling osteoclast and osteoblast activity for maintaining bone mass and bone strength. Additionally, OPN has been linked to cardiovascular, inflammatory illnesses, as well as the onset and progression of cancer. OPN is a multifunctional protein that can interact with a variety of cell surface receptors, such as integrins, CD44, the urokinase-type plasminogen activator receptor (uPAR), as well as extracellular matrix (ECM) components (e.g. collagen and hydroxyapatite). These interactions contribute to its wide range of biological functions in general and has significant implications for bone biology, immunology and cancer, specifically. In this chapter, we summarize the structure of OPN with a focus on its molecular mechanisms of action in various cancers.

The Role of Extracellular Matrix Proteins in Breast Cancer

The extracellular matrix is a structure composed of many molecules, including fibrillar (types I, II, III, V, XI, XXIV, XXVII) and non-fibrillar collagens (mainly basement membrane collagens: types IV, VIII, X), non-collagenous glycoproteins (elastin, laminin, fibronectin, thrombospondin, tenascin, osteopontin, osteonectin, entactin, periostin) embedded in a gel of negatively charged water-retaining glycosaminoglycans (GAGs) such as non-sulfated hyaluronic acid (HA) and sulfated GAGs which are linked to a core protein to form proteoglycans (PGs). This highly dynamic molecular network provides critical biochemical and biomechanical cues that mediate the cell–cell and cell–matrix interactions, influence cell growth, migration and differentiation and serve as a reservoir of cytokines and growth factors’ action. The breakdown of normal ECM and its replacement with tumor ECM modulate the tumor microenvironment (TME) composition and is an essential part of tumorigenesis and metastasis, acting as key driver for malignant progression. Abnormal ECM also deregulate behavior of stromal cells as well as facilitating tumor-associated angiogenesis and inflammation. Thus, the tumor matrix modulates each of the classically defined hallmarks of cancer promoting the growth, survival and invasion of the cancer. Moreover, various ECM-derived components modulate the immune response affecting T cells, tumor-associated macrophages (TAM), dendritic cells and cancer-associated fibroblasts (CAF). This review article considers the role that extracellular matrix play in breast cancer. Determining the detailed connections between the ECM and cellular processes has helped to identify novel disease markers and therapeutic targets.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Osteopontin level and promoter polymorphism in patients with metastatic breast cancer

Background

Cancer initiation typically occurs when a proto-oncogene's coding region undergoes mutation, resulting in uncontrollable cell growth and division, or when a tumour suppressor gene's coding region is affected by a mutation that inhibits activity of the resulting gene product. The pathophysiologic result is, respectively, exaggerated cell-cycle growth or deficient programmed cell death. Osteopontin (opn) is an integrin-binding phosphoprotein that is expressed on the surface of normal cells. Osteopontin has a major role in diverse tumour components, especially those implicated in invasion and metastasis. In the present study, we aimed to illustrate the value of opn as a possible contributor in breast cancer (bca).

Methods

This prospective study included 115 patients newly diagnosed with bca and distant metastasis who were recruited from the Oncology Center, Mansoura University, and the Department of Clinical Oncology and Nuclear Medicine, Mansoura University Hospital, Egypt. The patients recruited had been diagnosed with disseminated visceral metastasis (visceral crisis), with or without bone metastasis; patients with cranial metastasis were excluded from the study. All patients received first-line chemotherapy with docetaxel 75 mg/m2 plus cisplatin 75 mg/m2 or carboplatin 6 auc (area under the curve) on day 1 every 21 days for a maximum of 6 cycles or till development of toxicity. Trastuzumab (in cases of her2-positive disease) was given whenever possible (if government assistance or personal finances permitted). Serum levels of opn were assessed by enzyme-linked immunosorbent assay (elisa) before treatment was started. A group of 30 matched healthy women whose median serum opn level was 15 ng/dL were included, and that level was therefore defined as the cut-off value. In addition, opn gene mutation was determined by polymerase chain reaction (pcr). Correlations of pretreatment serum opn and opn gene mutation with various patient clinicopathologic variables, response to the treatment, progression-free survival (pfs), and overall survival (os) were assessed.

Results

Mean serum opn was highest in her2-amplified bca (64.4 ± 42.3 ng/dL), and then in triple-negative bca (55.9 ± 34.7 ng/dL), followed by the luminal B and A subtypes (38.4 ± 33.1 ng/dL and 36.3 ± 32.2 ng/dL respectively, p = 0.017). Testing by pcr revealed that opn gene mutation was highest in triple-negative bca (85% opn mutant vs. 15% non-mutant), and then in her2-overexpressed bca (80% opn mutant vs. 20% non-mutant), followed by luminal B bca (61.9% opn mutant vs. 38.1% non-mutant); the least expression was detected in luminal A bca (57.9% opn mutant vs. 42.1% non-mutant). Interestingly, patients with high serum opn and opn gene mutation experienced both poor pfs (median: 12 months vs. 14 months; p = 0.001) and poor os (median: 14 months vs. 18 months; p = 0.001). Moreover, participants with opn gene mutation experienced a poor response: of those with progressive disease, 74% had opn mutation and 26% had unmutated opn (p = 0.04). Additionally, high pretreatment serum opn was correlated with poor treatment response: 49.1 ± 33.8 ng/dL in patients with progressive disease and 35.5 ± 34.3 ng/dL in those who achieved a complete response, a partial response, or stable disease (p = 0.05). Strong concordance was found between high serum opn and opn gene mutation in 69 tumours (79.3%), and strong concordance was detected between normal or low serum opn and non-mutant opn in 28 tumours (60.8%).

Conclusions

The current prospective work helps to highlight opn as a valid prognostic biomarker for patients with metastatic bca and reveals that high pretreatment serum opn and opn gene mutation are both strongly linked with poor response and survival. Concordance between elisa and pcr results indicates that either method can be used for the evaluation of opn. Increased opn gene mutation in triple-negative bca could assist in tailoring the treatment response in this very aggressive tumour subtype and could be considered a targetable molecule in future studies.

Isoform-specific promotion of breast cancer tumorigenicity by TBX3 involves induction of angiogenesis

TBX3 is a member of the highly conserved family of T-box transcription factors involved in embryogenesis, organogenesis and tumor progression. While the functional role of TBX3 in tumorigenesis has been widely studied, less is known about the specific functions of the different isoforms (TBX3iso1 and TBX3iso2) which differ in their DNA-binding domain. We therefore sought to investigate the functional consequence of this highly conserved splice event as it relates to TBX3-induced tumorigenesis. By utilizing a nude mouse xenograft model, we have identified differential tumorigenic potential between TBX3 isoforms, with TBX3iso1 overexpression more commonly associated with invasive carcinoma and high tumor vascularity. Transcriptional analysis of signaling pathways altered by TBX3iso1 and TBX3iso2 overexpression revealed significant differences in angiogenesis-related genes. Importantly, osteopontin (OPN), a cancer-associated secreted phosphoprotein, was significantly up-regulated with TBX3iso1 (but not TBX3iso2) overexpression. This pattern was observed across three non/weakly-tumorigenic breast cancer cell lines (21PT, 21NT, and MCF7). Up-regulation of OPN in TBX3iso1 overexpressing cells was associated with induction of hyaluronan synthase 2 (HAS2) expression and increased retention of hyaluronan in pericellular matrices. These transcriptional changes were accompanied by the ability to induce endothelial cell vascular channel formation by conditioned media in vitro, which could be inhibited through addition of an OPN neutralizing antibody. Within the TCGA breast cancer cohort, we identified an 8.1-fold higher TBX3iso1 to TBX3iso2 transcript ratio in tumors relative to control, and this ratio was positively associated with high-tumor grade and an aggressive molecular subtype. Collectively, the described changes involving TBX3iso1-dependent promotion of angiogenesis may thus serve as an adaptive mechanism within breast cancer cells, potentially explaining differences in tumor formation rates between TBX3 isoforms in vivo. This study is the first of its kind to report significant functional differences between the two TBX3 isoforms, both in vitro and in vivo.

The Tumor Microenvironment: Focus on Extracellular Matrix

The extracellular matrix (ECM) regulates the development and maintains tissue homeostasis. The ECM is composed of a complex network of molecules presenting distinct biochemical properties to regulate cell growth, survival, motility, and differentiation. Among their components, proteoglycans (PGs) are considered one of the main components of ECM. Its composition, biomechanics, and anisotropy are exquisitely tuned to reflect the physiological state of the tissue. The loss of ECM's homeostasis is seen as one of the hallmarks of cancer and, typically, defines transitional events in tumor progression and metastasis. In this chapter, we discuss the types of proteoglycans and their roles in cancer. It has been observed that the amount of some ECM components is increased, while others are decreased, depending on the type of tumor. However, both conditions corroborate with tumor progression and malignancy. Therefore, ECM components have an increasingly important role in carcinogenesis and this leads us to believe that their understanding may be a key in the discovery of new anti-tumor therapies. In this book, the main ECM components will be discussed in more detail in each chapter.

Inactivation of mTORC2 in macrophages is a signature of colorectal cancer that promotes tumorigenesis

The mechanistic target of rapamycin complex 2 (mTORC2) is a potentially novel and promising anticancer target due to its critical roles in proliferation, apoptosis, and metabolic reprogramming of cancer cells. However, the activity and function of mTORC2 in distinct cells within malignant tissue in vivo is insufficiently explored. Surprisingly, in primary human and mouse colorectal cancer (CRC) samples, mTORC2 signaling could not be detected in tumor cells. In contrast, only macrophages in tumor-adjacent areas showed mTORC2 activity, which was downregulated in stromal macrophages residing within human and mouse tumor tissues. Functionally, inhibition of mTORC2 by specific deletion of Rictor in macrophages stimulated tumorigenesis in a colitis-associated CRC mouse model. This phenotype was driven by a proinflammatory reprogramming of mTORC2-deficient macrophages that promoted colitis via the cytokine SPP1/osteopontin to stimulate tumor growth. In human CRC patients, high SPP1 levels and low mTORC2 activity in tumor-associated macrophages correlated with a worsened clinical prognosis. Treatment of mice with a second-generation mTOR inhibitor that inhibits mTORC2 and mTORC1 exacerbated experimental colorectal tumorigenesis in vivo. In conclusion, mTORC2 activity is confined to macrophages in CRC and limits tumorigenesis. These results suggest activation but not inhibition of mTORC2 as a therapeutic strategy for colitis-associated CRC.

A targeted mass spectrometry immunoassay to quantify osteopontin in fresh-frozen breast tumors and adjacent normal breast tissues

Osteopontin (OPN) is a multifunctional protein that can activate cell-signaling pathways and lead to cancer development and metastasis. Elevated OPN expression was reported in different cancer types, including breast tumors. Here, we present a new immuno-mass spectrometry method for OPN quantification in fresh-frozen malignant and adjacent normal human breast tissues. For quantification we used two proteotypic peptides: OPN-peptide-1 and OPN-peptide-2. Peptide concentrations were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring (MRM) mode with stable isotope standards (SIS) and immuno-affinity enrichment for isolation of OPN peptides. Based on the OPN-peptide-1, the average OPN concentration in normal breast tissue was 19.42 μg/g, while the corresponding level in breast tumors was 603.9 μg/g. Based on OPN-peptide-2, the average concentration in normal breast tissue was 19.30 μg/g and in breast tumors 535.0 μg/g. In ER/PR/HER2(-) patients the OPN levels in breast tumors were significantly higher than in corresponding normal breast tissue samples, whereas in the single ER/PR/HER2(+) patient the OPN concentration in tumor samples was lower than in normal breast tissue sample. In conclusion, the current method is considered promising for the quantification of OPN in research and in clinical settings and should be further studied in breast cancer patients. SIGNIFICANCE: A new immuno-mass spectrometry method was successfully developed and applied to determine OPN concentrations in malignant tumor and normal breast tissues from six patients, and the method is promising for OPN quantification in both research and clinical settings.

Prognostic value of osteopontin expression in esophageal squamous cell carcinoma: A meta-analysis

OBJECTIVE

To explore the prognostic role of osteopontin (OPN) overexpression in esophageal squamous cell carcinoma (ESCC).

METHODS

The PubMed, EMBASE, The Cochrane Library, China National Knowledge Infrastructure, Wanfang, Chinese Biomedical Data (CBM) and VIP databases were searched from the establishment dates of the databases to March 31, 2019, for potentially related studies. Stata 12.0 software was used for statistical analyses, and the hazard ratios (HRs) with 95% confidence intervals (CIs) were combined to assess the correlation of OPN overexpression with the overall survival (OS) and progression-free survival (PFS) of ESCC patients.

RESULTS

A total of 8 studies involving 811 patients from China or Japan were included. OPN overexpression was demonstrated to be significantly associated with poor OS (HR = 1.86, 95% CI: 1.22-2.83, P = 0.004), with high heterogeneity (I² = 61.2%, P = 0.012), and poor PFS (HR=1.63, 95% CI: 1.08-2.47, P = 0.020), without heterogeneity (I² = 0.0%, P = 0.839). Subgroup analysis results were similar to the pooled results.

CONCLUSION

OPN overexpression might serve as a promising independent prognostic risk factor in Chinese and Japanese ESCC patients. However, more well-designed studies enrolling more patients are still needed to verify our findings.

The role of osteopontin in the progression of solid organ tumour

Osteopontin (OPN) is a bone sialoprotein involved in osteoclast attachment to mineralised bone matrix, as well as being a bone matrix protein, OPN is also a versatile protein that acts on various receptors which are associated with different signalling pathways implicated in cancer. OPN mediates various biological events involving the immune system and the vascular system; the protein plays a role in processes such as immune response, cell adhesion and migration, and tumorigenesis. This review discusses the potential role of OPN in tumour cell proliferation, angiogenesis and metastasis, as well as the molecular mechanisms involved in these processes in different cancers, including brain, lung, kidney, liver, bladder, breast, oesophageal, gastric, colon, pancreatic, prostate and ovarian cancers. The understanding of OPN’s role in tumour development and progression could potentially influence cancer therapy and contribute to the development of novel anti-tumour treatments.

Integrin β3 and CD44 levels determine the effects of the OPN-a splicing variant on lung cancer cell growth

Osteopontin (OPN), a phosphorylated glycoprotein, is frequently overexpressed in cancer. Among the three OPN isoforms, OPN-a is the most highly expressed in lung cancer cell lines and lung tumors. Overexpression of OPN-a greatly reduced CL1-5 lung adenocarcinoma cell growth, but had no effect on growth in A549 lung adenocarcinoma cells. Examination of the expression of integrins and CD44, which are possible OPN-a receptors, revealed that differences in integrin β3 levels might explain this discrepancy between CL1-5 and A549 cells. When integrin β3 was ectopically expressed in A549 cells, OPN-a inhibited their growth, whereas OPN-a increased cell growth following integrin β3 knockdown in CL1-5 cells. This OPN-a-induced increase in growth appeared to result from activation of the CD44/NFκB pathway. Our results demonstrated that OPN-a inhibits growth of cells with high integrin β3 levels and increases growth via activation of the CD44/NFκB pathway in cells with low integrin β3 levels. Thus, OPN-a, integrin β3, and CD44 interact to affect lung cancer cell growth, and this study may aid in the development of cancer treatment strategies involving these molecules.

Human Kallikrein 3 (prostate-specific antigen) and Human Kallikrein 5 Expression in Salivary Gland Tumors

The human kallikrein 5 protein (hK5) is expressed in many normal tissues, most notably in skin, breast, salivary gland and esophagus. It has also been shown to be a potential biomarker for breast, ovarian and testicular cancer. Human kallikrein 3 (hK3; prostate-specific antigen) is the most useful marker for adenocarcinoma of the prostate gland. The aim of this study was to determine whether hK3 and hK5 are expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), in order to compare normal with tumor tissues. Pleomorphic adenomas, adenoid cystic carcinomas, polymorphous low-grade adenocarcinomas, acinic cell carcinomas, mucoepidermoid carcinomas and adenocarcinomas not otherwise specified of both minor and major salivary glands were examined. The results of this study indicate that most salivary gland tumors do not show high levels of expression of hK5. Staining was most prominent in keratinizing epithelia in pleomorphic adenomas. hK3 is not expressed in salivary gland tumors.

Human Kallikrein 13 Expression in Salivary Gland Tumors

The human kallikrein 13 protein (hK13) is expressed in many normal tissues. Petraki et al have previously described presence of hK13 in salivary gland tissue, localized to duct epithelia and some acinar cells. The aim of this study was to determine whether hK13 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), in order to compare normal with tumor tissues. Pleomorphic adenomas (PA), adenoid cystic carcinomas (ACC), polymorphous low grade adenocarcinomas (PLGA), acinic cell carcinomas (ACI), mucoepidermoid carcinomas (MEC) and adenocarcinomas not otherwise specified (ANOS) of both minor and major salivary glands were examined. The results of this study indicate that most salivary gland tumors show high levels of expression of hK13. Overall, staining in PA was significantly less than that seen in normal salivary gland tissue. PLGA, ACC and ANOS each stained significantly more than normal salivary gland tissue while MEC and ACI did not. Ductal cells and cells lining duct-like structures showed a higher intensity of staining than non-ductal cells in most tumors. Tumors which exhibited only non-ductal cells also exhibited cytoplasmic staining. In conclusion, we demonstrate the high expression of hK13 in several common salivary gland tumors.

Osteopontin Expression According to Molecular Profile of Invasive Breast Cancer: A Clinicopathological and Immunohistochemical Study

Osteopontin (OPN) is a secreted, calcium-binding phosphorylated glycoprotein involved in several physiological and pathological events such as angiogenesis, apoptosis, inflammation, wound healing, vascular remodeling, calcification of mineralized tissues, and induction of cell proteases. There is growing interest in the role of OPN in breast cancer. In an attempt to obtain new insight into the pathogenesis of OPN-associated breast carcinomas, an immunohistochemical panel with 17 primary antibodies including cytokeratins and key regulators of the cell cycle was performed in 100 formalin-fixed paraffin-embedded samples of invasive breast carcinomas. OPN was expressed in 65% of tumors and was negatively correlated with estrogen (p=0.0350) and progesterone (p=0.0069) receptors, but not with the other markers and clinicopathological features evaluated including age, menstrual status, pathological grading, tumor size, and metastasis. There was no correlation between OPN expression and carcinomas of the basal-like phenotype (p=0.1615); however, OPN correlated positively with c-erbB-2 status (p=0.0286) and negatively with carcinomas of the luminal subtype (p=0.0353). It is well known that carcinomas overexpressing c-erbB-2 protein have a worse prognosis than luminal tumors. Here, we hypothesize that the differential expression of OPN in the first subtype of carcinomas may contribute to their more aggressive behavior.

Osteopontin at the Crossroads of Inflammation and Tumor Progression

Complex interactions between tumor and host cells regulate systemic tumor dissemination, a process that begins early at the primary tumor site and goes on until tumor cells detach themselves from the tumor mass and start migrating into the blood or lymphatic vessels. Metastatic cells colonize the target organs and are capable of surviving and growing at distant sites. In this context, osteopontin (OPN) appears to be a key determinant of the crosstalk between cancer cells and the host microenvironment, which in turn modulates immune evasion. OPN is overexpressed in several human carcinomas and has been implicated in inflammation, tumor progression, and metastasis. Thus, it represents one of the most attracting targets for cancer therapy. Within the tumor mass, OPN is secreted in various forms either by the tumor itself or by stroma cells, and it can exert either pro- or antitumorigenic effects according to the cell type and tumor microenvironment. Thus, targeting OPN for therapeutic purposes needs to take into account the heterogeneous functions of the multiple OPN forms with regard to cancer formation and progression. In this review, we will describe the role of systemic, tumor-derived, and stroma-derived OPN, highlighting its pivotal role at the crossroads of inflammation and tumor progression.

Soluble bone-derived osteopontin promotes migration and stem-like behavior of breast cancer cells

Breast cancer is a leading cause of cancer death in women, with the majority of these deaths caused by metastasis to distant organs. The most common site of breast cancer metastasis is the bone, which has been shown to provide a rich microenvironment that supports the migration and growth of breast cancer cells. Additionally, growing evidence suggests that breast cancer cells that do successfully metastasize have a stem-like phenotype including high activity of aldehyde dehydrogenase (ALDH) and/or a CD44⁺CD24^- phenotype. In the current study, we tested the hypothesis that these ALDH^hiCD44⁺CD24^- breast cancer cells interact with factors in the bone secondary organ microenvironment to facilitate metastasis. Specifically, we focused on bone-derived osteopontin and its ability to promote the migration and stem-like phenotype of breast cancer cells. Our results indicate that bone-derived osteopontin promotes the migration, tumorsphere-forming ability and colony-forming ability of whole population and ALDH^hiCD44⁺CD24^- breast cancer cells in bone marrow-conditioned media (an ex vivo representation of the bone microenvironment) (p≤0.05). We also demonstrate that CD44 and RGD-dependent cell surface integrins facilitate this functional response to bone-derived osteopontin (p≤0.05), potentially through activation of WNK-1 and PRAS40-related pathways. Our findings suggest that soluble bone-derived osteopontin enhances the ability of breast cancer cells to migrate to the bone and maintain a stem-like phenotype within the bone microenvironment, and this may contribute to the establishment and growth of bone metastases.

Association of osteopontin with specific prognostic factors and survival in adjuvant breast cancer trials of the Hellenic Cooperative Oncology Group

BACKGROUND

The shift towards an earlier diagnosis of breast cancer (BC) highlights the need for biomarkers that would identify patients at risk for relapse and metastatic spread and indicate the potential value of additional treatment strategies. Osteopontin (OPN) is a matricellular protein that has been suggested to be a potential biomarker in BC. In the present study, we used archived BC patient samples to assess the clinical utility of OPN.

METHODS

Formalin-fixed paraffin-embedded tumor tissue samples from 975 patients were collected from two large phase III randomized adjuvant chemotherapy trials (HE10/97 and HE10/00) that included patients with high risk BC. All tissue samples were assessed for ER, PgR, Ki67 and HER2 protein expression. OPN protein and mRNA expression was evaluated using immunohistochemistry and quantitative reverse transcription-polymerase chain reaction, respectively.

RESULTS

OPN mRNA expression data were available for 814 patients, whereas OPN protein expression data were available for 546 patients. The majority of patients were ER/PgR-positive (78.3%), HER2-negative (76.5%) and Ki67-positive (55.2%) and had received adjuvant radiation therapy (76.8%) and hormonal therapy (81.1%). OPN mRNA expression was significantly associated with age (60.9% in high OPN tumors vs. 54.1% in low OPN tumors, p = 0.047), ER/PgR-negative status (25.7 vs. 17.2%, p = 0.004) and BC subtypes (p = 0.021). In addition, high OPN mRNA expression was significantly associated with reduced DFS (HR 1.26, 95% CI 1.00-1.59, Wald's p = 0.050) and OS (HR 1.37, 95% CI 1.05-1.78, p = 0.019), while it retained its prognostic significance for both DFS (HR 1.39, 95% CI 1.10-1.77, p = 0.007) and OS (HR 1.54, 95% CI 1.61-2.05, p = 0.003) in the multivariate analysis.

CONCLUSIONS

We showed that high OPN mRNA expression is associated with decreased DFS and OS in a large cohort of BC patients treated with adjuvant chemotherapy in a clinical trial setting. Our results suggest that OPN may serve as a prognostic factor and a potential target for therapy. Trial registration Australian New Zealand Clinical Trials Registry; HE10/97 ACTRN12611000506998; HE10/00 ACTRN12609001036202.

Osteopontin as a discriminating marker for pancreatic cancer and chronic pancreatitis

INTRODUCTION

We analyzed concentrations of osteopontin (OPN) in patients with pancreatic ductal adenocarcinoma (PDAC) in order to determine firstly whether it is useful to distinguish between PDAC patients and those with chronic non-hereditary pancreatitis (CP) and type 2 diabetes mellitus (T2DM), and secondly whether OPN concentrations depend on the PDAC stage.

METHODS

Groups consisting of 64 patients with PDAC, 71 with CP, 67 with T2DM and 48 healthy controls (CON) were enrolled in the study. Controls were compared with regard to levels of OPN, oxidative stress markers, conventional tumor markers and other biochemical parameters.

RESULTS

Levels of OPN were higher in patients with PDAC compared with CP patients (P< 0.001), T2DM (P< 0.001) and CON (P< 0.001). There were increased OPN levels in CP patients in comparison with T2DM (P< 0.001) and CON (P< 0.001). Patients with PDAC in stage IV had higher OPN levels than PDAC patients in stage III (P< 0.01). There was no difference in OPN levels of PDAC patients in stage III compared to patients in stage II.

CONCLUSION

Our pilot study demonstrates the usefulness of estimating OPN levels to differentiate between pancreatic cancer and chronic pancreatitis. Higher OPN levels over 102 ng/ml could be a potential diagnostic biomarker for pancreatic cancer.

Prognostic Value of Osteopontin Splice Variant-c Expression in Breast Cancers: A Meta-Analysis

Objectives. Osteopontin (OPN) is overexpressed in breast cancers, while its clinical and prognostic significance remained unclear. This study aimed to assess the prognostic value of OPN, especially its splice variants, in breast cancers. Methods. Data were extracted from eligible studies concerning the OPN and OPN-c expression in breast cancer patients and were used to calculate the association between OPN/OPN-c and survival. Two reviewer teams independently screened the literatures according to the inclusion and exclusion criteria based on quality evaluation. Following the processes of data extraction, assessment, and transformation, meta-analysis was carried out via RevMan 5.3 software. Results. A total of ten studies involving 1,567 patients were included. The results demonstrated that high level OPN indicated a poor outcome in the OS (HR = 2.22, 95% CI: 1.23–4.00, and P = 0.008; random-effects model) with heterogeneity (I² = 62%) of breast cancer patients. High level OPN-c appeared to be more significantly associated with poor survival (HR = 2.14, 95% CI: 1.51–3.04, and P < 0.0001; fixed-effects model) with undetected heterogeneity (I² = 0%). Conclusions. Our analyses indicated that both OPN and OPN-c could be considered as prognostic markers for breast cancers. The high level of OPN-c was suggested to be more reliably associated with poor survival in breast cancer patients.

Human Kallikrein 6 Expression in Salivary Gland Tumors

Human kallikrein 6 (hK6), also known as zyme/protease M/neurosin), is expressed in many normal glandular tissues. The aim of this study was to determine whether hK6 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), using an immunohistochemical method. Pleomorphic adenomas (PA), adenoid cystic carcinomas, polymorphous low-grade adenocarcinomas, acinic cell carcinomas, mucoepidermoid carcinomas, and adenocarcinomas not otherwise specified of both minor and major salivary glands were examined. Cells lining duct-like structures and non-duct-like cells were scored. Only in PA of minor salivary gland origin was overall staining higher in duct-like than in non-duct-like cells. In all other tumors exhibiting both types of cells, hK6 staining was similar in both duct-like and non-duct-like cells. Tumors that exhibited non-duct-like cells only also exhibited cytoplasmic staining. Results of this study show that salivary gland tumors express hK6, apparently downregulated in comparison with normal salivary gland tissue, and that this expression is not specific for any of the tumors studied.

Osteopontin regulates proliferation, apoptosis, and migration of murine claudin-low mammary tumor cells

Background

Osteopontin is a secreted phosphoglycoprotein that is expressed by a number of normal cells as well as a variety of tumor cells. With respect to breast cancer, osteopontin has been implicated in regulating tumor cell proliferation and migration/metastasis and may serve as a prognostic indicator. However it remains unclear whether osteopontin has the same impact in all breast cancer subtypes and in particular, osteopontin’s effects in claudin-low breast cancer are poorly understood.

Methods

cDNA microarrays and qRT-PCR were used to evaluate osteopontin expression in mammary tumors from MTB-IGFIR transgenic mice and cell lines derived from these tumors. siRNA was then used to determine the impact of osteopontin knockdown on proliferation, apoptosis and migration in vitro in two murine claudin-low cell lines as well as identify the receptor mediating osteopontin’s physiologic effects.

Results

Osteopontin was expressed at high levels in mammary tumors derived from MTB-IGFIR transgenic mice compared to normal mammary tissue. Evaluation of cell lines derived from different mammary tumors revealed that mammary tumor cells with claudin-low characteristic expressed high levels of osteopontin whereas mammary tumor cells with mixed luminal and basal-like features expressed lower levels of osteopontin. Reduction of osteopontin levels using siRNA significantly reduced proliferation and migration while increasing apoptosis in the claudin-low cell lines. Osteopontin’s effect appear to be mediated through a receptor containing ITGAV and not through CD44.

Conclusions

Our data suggests that mammary tumors with a mixed luminal/basal-like phenotype express high levels of osteopontin however this osteopontin appears to be largely produced by non-tumor cells in the tumor microenvironment. In contrast tumor cells with claudin-low characteristics express high levels of osteopontin and a reduction of osteopontin in these cells impaired proliferation, survival and migration.

The extracellular matrix in breast cancer

The extracellular matrix (ECM) is increasingly recognized as an important regulator in breast cancer. ECM in breast cancer development features numerous changes in composition and organization when compared to the mammary gland under homeostasis. Matrix proteins that are induced in breast cancer include fibrillar collagens, fibronectin, specific laminins and proteoglycans as well as matricellular proteins. Growing evidence suggests that many of these induced ECM proteins play a major functional role in breast cancer progression and metastasis. A number of the induced ECM proteins have moreover been shown to be essential components of metastatic niches, promoting stem/progenitor signaling pathways and metastatic growth. ECM remodeling enzymes are also markedly increased, leading to major changes in the matrix structure and biomechanical properties. Importantly, several ECM components and ECM remodeling enzymes are specifically induced in breast cancer or during tissue regeneration while healthy tissues under homeostasis express exceedingly low levels. This may indicate that ECM and ECM-associated functions may represent promising drug targets against breast cancer, providing important specificity that could be utilized when developing therapies.

Clinical and prognostic significance of OPN and VEGF expression in patients with non-small-cell lung cancer

BACKGROUND

Osteopontin (OPN) and vascular endothelial growth factor (VEGF) play important roles in cancer progression and angiogenesis. In the current study we aimed to investigate the clinical significance of OPN and VEGF expression in patients with non-small-cell lung cancer (NSCLC) and to investigate their prognostic value for NSCLC.

METHODS

Immunohistochemical staining was used to detect the expression of OPN and VEGF in 146 NSCLC patients undergoing surgical resection in our hospital between 2006 and 2008. The associations between OPN and VEGF expression and clinicopathological data were analyzed using chi-square test analysis. Survival analysis was performed using the Kaplan-Meier method. The prognostic values of OPN and VEGF were evaluated by univariate and multivariate Cox proportional hazard model analysis.

RESULTS

OPN and VEGF expression was positive in 94 and 86 out of 146 NSCLC specimens, respectively. OPN expression was significantly associated with gender (P=0.002), TNM stage (P<0.001) and tumor differentiation (P=0.008). VEGF expression was significantly associated with TNM stage (P=0.015), tumor differentiation (P=0.032) and lymph-node status (P<0.001). There was a significant correlation between OPN and VEGF expression (P=0.035). Survival analysis indicated that OPN(+)/VEGF(+) patients had the worst prognosis. Furthermore, univariate and multivariate analysis suggested that tumor stage, lymph-node metastases, OPN expression and VEGF expression were independent prognostic factors for NSCLC.

CONCLUSION

The data suggest that OPN and VEGF expressions could serve as prognostic factors for NSCLC.

Combined Proteomics and Transcriptomics Identifies Carboxypeptidase B1 and Nuclear Factor κB (NF-κB) Associated Proteins as Putative Biomarkers of Metastasis in Low Grade Breast Cancer

Current prognostic factors are insufficient for precise risk-discrimination in breast cancer patients with low grade breast tumors, which, in disagreement with theoretical prognosis, occasionally form early lymph node metastasis. To identify markers for this group of patients, we employed iTRAQ-2DLC-MS/MS proteomics to 24 lymph node positive and 24 lymph node negative grade 1 luminal A primary breast tumors. Another group of 48 high-grade tumors (luminal B, triple negative, Her-2 subtypes) was also analyzed to investigate marker specificity for grade 1 luminal A tumors. From the total of 4405 proteins identified (FDR < 5%), the top 65 differentially expressed together with 30 previously identified and control markers were analyzed also at transcript level. Increased levels of carboxypeptidase B1 (CPB1), PDZ and LIM domain protein 2 (PDLIM2), and ring finger protein 25 (RNF25) were associated specifically with lymph node positive grade 1 tumors, whereas stathmin 1 (STMN1) and thymosin beta 10 (TMSB10) associated with aggressive tumor phenotype also in high grade tumors at both protein and transcript level. For CPB1, these differences were also observed by immunohistochemical analysis on tissue microarrays. Up-regulation of putative biomarkers in lymph node positive (versus negative) luminal A tumors was validated by gene expression analysis of an independent published data set (n = 343) for CPB1 (p = 0.00155), PDLIM2 (p = 0.02027) and RELA (p = 0.00015). Moreover, statistically significant connections with patient survival were identified in another public data set (n = 1678). Our findings indicate unique pro-metastatic mechanisms in grade 1 tumors that can include up-regulation of CPB1, activation of NF-κB pathway and changes in cell survival and cytoskeleton. These putative biomarkers have potential to identify the specific minor subpopulation of breast cancer patients with low grade tumors who are at higher than expected risk of recurrence and who would benefit from more intensive follow-up and may require more personalized therapy.

MRTF-A and STAT3 promote MDA-MB-231 cell migration via hypermethylating BRSM1

Breast cancer is the leading cause of cancer death in women worldwide which is closely related to metastasis. But the exact molecular mechanism of metastasis is still not fully understood. We now report that both MRTF-A and STAT3 play important roles in migration of MDA-MB-231 breast cancer cells. Moreover, MRTF-A and STAT3 synergistically increased MDA-MB-231 cell migration by promoting the expression of migration markers urokinase-type plasminogen activator (uPA) and osteopontin (OPN) and inhibiting the expression of breast cancer metastasis suppressor 1 (BRMS1). Luciferase reporter assays demonstrated that MRTF-A and STAT3 do not affect transcription of the BRMS1 promoter. Instead, we identified a newly molecular mechanism by which MRTF-A and STAT3 synergistically controlled MDA-MB-231 cell migration by recruiting DNMT1 to hypermethylate the promoter of BRMS1 and thus affect the expression of BRMS1. Interestingly, physical interaction between MRTF-A and STAT3 synergistically promotes the transactivity of DNMT1 by binding to the GAS element within the DNMT1 promoter. Our data thus provide important and novel insights into the roles of MRTF-A and STAT3 in regulating MDA-MB-231 cell migration.

Nuclear osteopontin-c is a prognostic breast cancer marker

BACKGROUND

Although Osteopontin has been known as a marker for cancer progression, the elevated production of this cytokine is not specific for cancer. We have identified the splice variant Osteopontin-c as being absent from healthy tissue but associated with about 75% of breast cancer cases. However, in previous studies of Osteopontin-c, follow-up information was not available.

METHODS

Here we have analysed 671 patients, comprising a cohort of 291 paraffin blocks plus a population-based case-control study of 380 arrayed breast tumor tissues.

RESULTS

We find that high staining intensity of nuclear Osteopontin-c is strongly associated with mortality in patients with early breast cancer. Cytosolic staining for exon 4, reflective of Osteopontin-a and -b also predicts poor outcome. By contrast, total Osteopontin does not correlate with prognosis. These diverse assessments of Osteopontin also do not correlate with each other, suggesting distinct expression patterns for the variant forms. Consistent with its role in tumor progression, not tumor initiation, Osteopontin-c is not correlated with proliferation markers (Ki-67, cyclin A, cyclin B, cyclin E and cyclin D), neither is it correlated with ER, PR or HER2.

CONCLUSIONS

The addition of Osteopontin-c immunohistochemistry to standard pathology work-ups may have prognostic benefit in early breast cancer diagnosis.

Extracellular molecules involved in cancer cell invasion

Nowadays it is perfectly clear that understanding and eradicating cancer cell invasion and metastasis represent the crucial, definitive points in cancer therapeutics. During the last two decades there has been a great interest in the understanding of the extracellular molecular mechanisms involved in cancer cell invasion. In this review, we highlight the findings concerning these processes, focusing in particular on extracellular molecules, including extracellular matrix proteins and their receptors, growth factors and their receptors, matrix metalloproteinases and extracellular chaperones. We report the molecular mechanisms underlying the important contribution of this pool of molecules to the complex, multi-step phenomenon of cancer cell invasion.

Osteopontin mediates an MZF1-TGF-β1-dependent transformation of mesenchymal stem cells into cancer-associated fibroblasts in breast cancer

Interactions between tumor cells and cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TMEN) significantly influence cancer growth and metastasis. Transforming growth factor-β (TGF-β) is known to be a critical mediator of the CAF phenotype, and osteopontin (OPN) expression in tumors is associated with more aggressive phenotypes and poor patient outcomes. The potential link between these two pathways has not been previously addressed. Utilizing in vitro studies using human mesenchymal stem cells (MSCs) and MDA-MB231 (OPN+) and MCF7 (OPN−) human breast cancer cell lines, we demonstrate that OPN induces integrin-dependent MSC expression of TGF-β1 to mediate adoption of the CAF phenotype. This OPN-TGF-β1 pathway requires the transcription factor, myeloid zinc finger 1 (MZF1). In vivo studies with xenotransplant models in NOD-scid mice showed that OPN expression increases cancer growth and metastasis by mediating MSC-to-CAF transformation in a process that is MZF1- and TGF-β1-dependent. We conclude that tumor-derived OPN engenders MSC-to-CAF transformation in the microenvironment to promote tumor growth and metastasis via the OPN-MZF1-TGF-β1 pathway.

Prognostic value of osteopontin expression in breast cancer: A meta-analysis

Osteopontin (OPN) has been implicated in tumor development and progression over the last few years. However, the prognostic value of OPN overexpression in patients with breast cancer remains controversial. We performed a meta-analysis to investigate the association of OPN expression in the tumor with the clinicopathological characteristics and survival of breast cancer patients. A total of 8 studies met the inclusion criteria and were entered in the meta-analysis. The data analysis demonstrated that OPN expression was positively associated with lymph node metastasis [pooled odds ratio = 2.026, 95% confidence interval (CI): 1.199-3.425, P=0.008, random-effects model]. We also found that OPN expression was positively associated with overall survival [hazard ratio (HR) = 3. 69, 95% CI: 1. 45-9.42, P=0.000, random-effects model) and disease -free survival (pooled HR=2.40, 95% CI: 1.27-4.55, P=0.007, fix ed -effects model). Based on the results of this study, we concluded that OPN overexpression in the tumor is a candidate positive prognostic biomarker for breast cancer patients.

Expression and localization of osteopontin, homing cell adhesion molecule/CD44, and integrin αvβ3 in pleomorphic adenoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma

OBJECTIVES

Osteopontin (OPN) plays a role in tumor progression. This study aimed to determine the expression of OPN, CD44, and integrin αvβ3 in pleomorphic adenoma (PA), polymorphous low-grade adenocarcinoma (PLGA), and adenoid cystic carcinoma (ACC).

STUDY DESIGN

Immunohistochemistry was used to semiquantify the level of expression of OPN and its receptors in normal salivary glands (NSG; n = 20), PA (n = 20), PLGA (n = 16), and ACC (n = 22).

RESULTS

OPN expression was increased in PLGA and intermediate-/high-grade ACC compared with PA and NSG (median scores, 6, 5, 4, and 4, respectively). CD44 expression was reduced in PA, PLGA, and ACC. OPN expression levels were moderately correlated with CD44 in PLGA. Integrin αvβ3 was not expressed in PA and ACC and was seen in only 1 case of PLGA.

CONCLUSIONS

OPN is expressed in salivary gland tumors but does not correlate well with CD44 and αvβ3.

Role of osteopontin in the pathophysiology of cancer

Osteopontin (OPN) is a multifunctional cytokine that impacts cell proliferation, survival, drug resistance, invasion, and stem like behavior. Due to its critical involvement in regulating cellular functions, its aberrant expression and/or splicing is functionally responsible for undesirable alterations in disease pathologies, specifically cancer. It is implicated in promoting invasive and metastatic progression of many carcinomas. Due to its autocrine and paracrine activities OPN has been shown to be a crucial mediator of cellular cross talk and an influential factor in the tumor microenvironment. OPN has been implicated as a prognostic and diagnostic marker for several cancer types. It has also been explored as a possible target for treatment. In this article we hope to provide a broad perspective on the importance of OPN in the pathophysiology of cancer.

Extracellular matrix components in breast cancer progression and metastasis

The extracellular matrix (ECM) is composed of highly variable and dynamic components that regulate cell behavior. The protein composition and physical properties of the ECM govern cell fate through biochemical and biomechanical mechanisms. This requires a carefully orchestrated and thorough regulation considering that a disturbed ECM can have serious consequences and lead to pathological conditions like cancer. In breast cancer, many ECM proteins are significantly deregulated and specific matrix components promote tumor progression and metastatic spread. Intriguingly, several ECM proteins that are associated with breast cancer development, overlap substantially with a group of ECM proteins induced during the state of tissue remodeling such as mammary gland involution. Fibrillar collagens, fibronectin, hyaluronan and matricellular proteins are matrix components that are common to both involution and cancer. Moreover, some of these proteins have in recent years been identified as important constituents of metastatic niches in breast cancer. In addition, specific ECM molecules, their receptors or enzymatic modifiers are significantly involved in resistance to therapeutic intervention. Further analysis of these ECM proteins and the downstream ECM mediated signaling pathways may provide a range of possibilities to identify druggable targets against advanced breast cancer.

Expression and localization of osteopontin, homing cell adhesion molecule/CD44, and integrin αvβ3 in mucoepidermoid carcinoma and acinic cell adenocarcinoma of salivary gland origin

OBJECTIVE

Osteopontin (OPN) plays a role in tumor progression. This study aimed to determine the expression of OPN, CD44, and integrin αvβ3 in pleomorphic adenoma (PA), acinic cell adenocarcinoma (ACA), and mucoepidermoid carcinoma (MEC).

STUDY DESIGN

Immunohistochemistry was used to semiquantify the levels of expression of OPN and its receptors in normal salivary glands (NSG) (n = 20), PA (n = 20), ACA (n = 11), and MEC (n = 29).

RESULTS

OPN expression was increased in ACA and MEC compared with PA and NSG (median scores, 6, 6, 4, and 4, respectively). CD44 expression was increased in ACA and reduced in MEC and PA compared with NSG (median scores, 8, 4, 3, and 5, respectively). Integrin αvβ3 median scores were 5 in ACA, 1 in MEC, and 0 in PA and NSG.

CONCLUSIONS

OPN is expressed in salivary gland tumors and is at higher levels in ACA and MEC.

Gene expression profiling of colorectal tumors and normal mucosa by microarrays meta-analysis using prediction analysis of microarray, artificial neural network, classification, and regression trees

BACKGROUND

Microarray technology shows great potential but previous studies were limited by small number of samples in the colorectal cancer (CRC) research. The aims of this study are to investigate gene expression profile of CRCs by pooling cDNA microarrays using PAM, ANN, and decision trees (CART and C5.0).

METHODS

Pooled 16 datasets contained 88 normal mucosal tissues and 1186 CRCs. PAM was performed to identify significant expressed genes in CRCs and models of PAM, ANN, CART, and C5.0 were constructed for screening candidate genes via ranking gene order of significances.

RESULTS

The first screening identified 55 genes. The test accuracy of each model was over 0.97 averagely. Less than eight genes achieve excellent classification accuracy. Combining the results of four models, we found the top eight differential genes in CRCs; suppressor genes, CA7, SPIB, GUCA2B, AQP8, IL6R and CWH43; oncogenes, SPP1 and TCN1. Genes of higher significances showed lower variation in rank ordering by different methods.

CONCLUSION

We adopted a two-tier genetic screen, which not only reduced the number of candidate genes but also yielded good accuracy (nearly 100%). This method can be applied to future studies. Among the top eight genes, CA7, TCN1, and CWH43 have not been reported to be related to CRC.

Breast cancer stem cells: Multiple capacities in tumor metastasis

Breast cancer is the leading cause of cancer death among women worldwide. Accumulating evidence indicates that the local recurrent and/or distant metastatic tumors, the major causes of lethality in the clinic, are related to the aggressive phenotype of a small fraction of cancer cells loosely termed as cancer stem cells (CSCs), tumor initiating cells (TICs), or cancer metastasis-initiating cells (CMICs). Breast cancer stem cells (BCSCs) are shown to exhibit unique growth abilities including self-renewal, differentiation potential, and resistance to most anti-cancer agents including chemo- and/or radiotherapy, all of which are believed to contribute to the development and overall aggressiveness of the recurrent or metastatic lesions. It is in the urgent need not only to further define the nature of heterogeneity in each tumor but also to characterize the precise mechanisms governing tumor-host cross-talk which is assumed to be initiated by BCSCs. In this review, we will focus on recently identified key factors, including the BCSCs among circulating tumor cells, interaction of BCSCs with the host, epithelial mesenchymal transition (EMT), tumor microenvironment, the intrinsic resistance due to HER2 expression, potential biomarkers of BCSCs and cancer cell immune signaling. We believe that new evidence coming from both bench and clinical research will help to develop more effective approaches to control or significantly reduce the aggressiveness of metastatic tumors.

Assessment of osteopontin in early breast cancer: correlative study in a randomised clinical trial

INTRODUCTION

Osteopontin (OPN) is a malignancy-associated glycoprotein that contributes functionally to tumor aggressiveness. In metastatic breast cancer, we previously demonstrated that elevated OPN in primary tumor and blood was associated with poor prognosis.

METHODS

We measured OPN in plasma by ELISA, and in tumors by immunohistochemistry, in 624 (94%) and 462 (69%), respectively, of 667 postmenopausal women with hormone responsive early breast cancer treated by surgery followed by adjuvant treatment with tamoxifen +/- octreotide in a randomized trial (NCIC CTG MA.14; National Cancer Institute of Canada Clinical Trials Group Mammary.14).

RESULTS

Plasma OPN was measured in 2,540 samples; 688 at baseline and 1,852 collected during follow-up. Mean baseline plasma OPN was 46 ng/ml (range 22.6 to 290) which did not differ from normal levels. Mean percentage OPN tumor cell positivity was 33.9 (95% CI: 30.2 to 37.9). There was no correlation between plasma and tumor OPN values. In multivariate analysis, neither was associated with event-free survival (EFS), relapse-free survival (RFS), overall survival (OS), bone RFS or non-bone RFS. An exploratory analysis in patients with recurrence showed higher mean OPN plasma levels 60.7 ng/ml (23.9 to 543) in the recurrence period compared with baseline levels.

CONCLUSIONS

The hypothesis that OPN tumor expression would have independent prognostic value in early breast cancer was not supported by multivariate analysis of this study population. Plasma OPN levels in women with hormone responsive early breast cancer in the MA.14 trial were not elevated and there was no evidence for prognostic value of plasma OPN in this defined group of patients. However, our finding of elevated mean OPN plasma level around the time of recurrence warrants further study.

TRIAL REGISTRATION

NCT00002864, http://clinicaltrials.gov/show/NCT00002864.

Patterns of metastatic spread in early breast cancer

AIMS

The aim of this study was to prospectively investigate metastatic pathways of spread to lymph node versus bone marrow and identify biological characteristics that determine these patterns in early invasive breast cancer.

PATIENTS AND METHODS

In all, 177 patients with early invasive breast cancer underwent surgical extirpation of the primary tumour with sentinel lymph node biopsy (SLNB). Bone marrow (BM) aspiration was performed to screen for cytokeratin-positive cells by immunocytochemistry. Lymphatic spread was assessed by histopathological examination of lymph nodes (LN). A representative subset of 87 tumours was analysed by tissue microarray (TMA) to evaluate expression of markers that potentially influence haematogenous vs. lymphatic spread. Patients were followed up for a median of 54.7 months.

RESULTS

Of the 177 patients, 114 (64%) were BM-/LN-, 38 (22%) BM-/LN+, 19 (11%) BM+/LN- and 6 (3%) BM+/LN+. Multivariate analysis of histopathological characteristics revealed that increasing tumour size was significantly associated with both LN positivity (p = 0.003) and BM positivity (p = 0.01), the presence of lymphovascular invasion significantly correlated with LN+ (p = 0.01), whereas lower histological grade was significantly associated with BM+ (p = 0.03). LN+ and BM+ were non-significantly negatively related to each other. Univariate analysis of the TMA data showed differential expression patterns for several factors; significant differences between effects on the two metastatic pathways (lymphatic vs. haematogenous) were found for expression of CD54 (p = 0.03), osteopontin (p = 0.04), bone sialoprotein (p = 0.04) and CXCR4 (p = 0.009). High expression of CD54, osteopontin and bone sialoprotein (BSP) was positively associated with BM + but was either not associated, or negatively associated, with LN+. High CXCR4 expression was positively associated with LN+ and negatively with BM+. High VEGF-C expression was associated with both LN+ and BM+, although this did not attain statistical significance. Due to the small number of clinical events during clinical follow-up, no associations were identified between metastatic spread patterns, recurrence and/or death.

CONCLUSION

These findings suggest that distinct lymphatic and haematogenous metastatic pathways exist in early breast cancer and that these pathways are governed by specific biological markers.

Prognostic significance of BMP7 as an oncogene in hepatocellular carcinoma

This study aims to evaluate the association between BMP7 tissue expression and patient prognosis in hepatocellular carcinoma (HCC). The expression of BMP7 mRNA in HCC was characterized using real-time PCR and 30 pairs of fresh frozen HCC tissues and corresponding noncancerous tissues. BMP7 protein expression in HCC was confirmed using immunohistochemistry on a tissue microarray chip. Finally, BMP7 expression was correlated with conventional clinicopathological features of HCC and patient outcome. The expression of BMP7 mRNA and protein in HCC cells was much higher than in normal hepatic cells. Our results showed that the high expression of BMP7 in HCC was related to tumor size (p < 0.001), histological differentiation (p = 0.041), serum AFP (p = 0.007), and tumor stage (p < 0.001). Kaplan-Meier survival analysis showed that a high-expression level of BMP7 resulted in a significantly poor prognosis of HCC patients. Multivariate analysis revealed that BMP7 expression level was an independent prognostic parameter for the overall survival rate of HCC patients. These findings provide evidence that a high-expression level of BMP7 serves as a biomarker for poor prognosis for HCC. Thus, we speculate that BMP7 may be a potential target of antiangiogenic therapy for HCC.

A bead-based multiplexed immunoassay to evaluate breast cancer biomarkers for early detection in pre-diagnostic serum

This study investigates whether a set of ten potential breast cancer serum biomarkers and cancer antigens (osteopontin (OPN), haptoglobin, cancer antigen 15-3 (CA15-3), carcinoembryonic antigen (CEA), cancer antigen 125 (CA-125), prolactin, cancer antigen 19-9 (CA19-9), α-fetoprotein (AFP), leptin and migration inhibitory factor (MIF)) can predict early stage breast cancer in samples collected before clinical diagnosis (phase III samples). We performed a nested case-control study within the Prospect-EPIC (European Prospective Investigation into Cancer and nutrition) cohort. We examined to what extent the biomarker panel could discriminate between 68 women diagnosed with breast cancer up to three years after enrollment and 68 matched healthy controls (all 56-64 years at baseline). Using a quantitative bead-based multiplexed assay, we determined protein concentrations in serum samples collected at enrollment. Principal Component Analysis (PCA) and Random Forest (RF) analysis revealed that on the basis of all ten proteins, early cases could not be separated from controls. When we combined serum protein concentrations and subject characteristics related to breast cancer risk in the RF analysis, this did not result in classification accuracy scores that could correctly classify the samples (sensitivity: 50%, specificity: 50%). Our findings indicate that this panel of selected tumor markers cannot be used for diagnosis of early breast cancer.

High expression of AP-4 predicts poor prognosis for hepatocellular carcinoma after curative hepatectomy

The aim of this study was to evaluate the association between activating enhancer binding protein 4 (AP-4) tissue expression and patient prognosis in hepatocellular carcinoma (HCC). The levels of AP-4 mRNA and protein in tumor and para-tumor tissue were evaluated in 30 HCC cases by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Additionally, AP-4 protein expression in 112 HCC was analyzed by immunohistochemistry. The correlation of AP-4 expression and patients' clinicopathological parameters was evaluated. Survival analysis was performed using the Kaplan-Meier method and Cox's proportional hazards model. By RT-PCR and Western blot, the levels of AP-4 mRNA and protein were significantly higher in HCC, compared to that in para-tumor tissue (p < 0.001). Immunohistochemical staining revealed that AP-4 was highly expressed in 53.6 % of the HCC patients. The AP-4 expression level was closely associated with serum alpha fetoprotein elevation, tumor size, histological differentiation, tumor recurrence, tumor metastasis, and tumor stage. Kaplan-Meier survival analysis showed that a high expression level of AP-4 resulted in a significantly poor prognosis of HCC patients. Multivariate analysis revealed that AP-4 expression level was an independent prognostic parameter for the overall survival rate of HCC patients. These findings provide evidence that a high expression level of AP-4 serves as a biomarker for poor prognosis for HCC. Thus, we speculate that AP-4 may be a potential target of antiangiogenic therapy for HCC.

High ADAM8 expression is associated with poor prognosis in patients with hepatocellular carcinoma

In this study,we investigated the ADAM8 expression in hepatocellular carcinoma (HCC) and its correlation with clinicopathologic features,including the survival of patients with HCC. Furthermore,we examined the biological processes regulated by ADAM8 during the development of using HepG2 cell line as a model system. We used immunohistochemistry to compare ADAM8 protein expression in HCC and normal liver tissues and further analyze the ADAM8 protein expression in clinicopathologically characterized 105 HCC cases.We stably knocked down the endogenous expression level of ADAM8 in HepG2 cells with specific shRNA-expressing lentiviral vector. Following the successful establishment of stable cells,we examined in vitro cell growth by MTT assay,anchorage-independent growth by soft-agar colony formation assay and cell migration/invasion by transwell and boyden chamber assay. And in addition,we also investigated the in vivo tumor growth by xenograft transplantation of HepG2 cells into nude mice. Protein expression level of ADAM8 was markedly higher in HCC tissues than that in the normal liver tissues (P = 0.0058).In addition,high expression of ADAM8 protein was positively correlated with serum AFP elevation,tumor size,histological differentiation,tumor recurrence,tumor metastasis,and tumor stage. Patients with higher ADAM8 expression showed a significantly shorter overall survival time than patients with low ADAM8 expression. Multivariate analysis suggested that ADAM8 expression might be an independent prognostic indicator (p = 0.016) for the survival of patients with HCC. ADAM8-specific shRNA (shADAM8) successfully knocked down its endogenous expression in HepG2 cells. Compared to the parental and control shRNA-transfected (shCtrl) HepG2 cells,the shADAM8 cells exhibited significantly reduced in vitro cell growth,anchorage-independent growth,cell migration and invasion (p < 0.05).In vivo,the xenograft transplants from shADAM8 cells gave rise to much smaller tumors as compared to those from shCtrl cells. High ADAM8 expression is associated with poor overall survival in patients with HCC. Down-regulation of ADAM8 inhibits the growth,anchorage-independent growth,migration and invasion of HepG2 cells. ADAM8 may be a potential target of antiangiogenic therapy for HCC.

Expression of ADAM8 and its clinical values in diagnosis and prognosis of hepatocellular carcinoma

ADAM8 behaves as an active metalloprotease in vitro, hydrolyzing myelin basic protein and a variety of peptide substrates based on the cleavage sites of membrane-bound cytokines, growth factors, and receptors. Other studies have demonstrated overexpression of some ADAM family proteins in a variety of human tumors, but no report is available on the actual expression of ADAM8 and the correlation between clinicopathologic features and prognosis of hepatocellular carcinoma (HCC) patients. In this study, serum levels of ADAM8 were measured by ELISA in 126 patients with HCC, 50 patients with liver cirrhosis (LC), and 50 healthy individuals. The expression of ADAM8 in liver tissue was further studied using Western blotting in 126 patients with HCC and 50 with LC. The correlations between ADAM8 status and various clinicopathological parameters including survival were analyzed. Survival analysis was performed using the Kaplan-Meier method and Cox's proportional hazards model. The ELISA assay showed that the serum levels of ADAM8 in the HCC, LC, and healthy groups were 136.4 ± 34.5, 64.2 ± 20.1, and 63.2 ± 22.7 U/ml, respectively. Analysis of variance was used for inter-group comparison, and differences were found between the HCC group and the other two groups (both P < 0.001), while no difference was found between the LC group and the healthy group (P = 0.365). Western blotting assay showed that ADAM8 protein expression was detected in 62.7 % (79/126) HCC and in 32 % (16/50) LC tissues. Further, ADAM8 expression was associated closely with serum AFP elevation, tumor size, histological differentiation, tumor recurrence, tumor metastasis, and tumor stage. Kaplan-Meier survival analysis showed that patients with ADAM8-positive tumors had a shorter postoperative survival time than those with ADAM8-negative tumors (P < 0.001). Multivariate analysis revealed that ADAM8 expression was an independent prognostic parameter for the overall survival rate of HCC patients. These findings provide evidence that the expression of ADAM8 serves as a poor prognostic biomarker for HCC. ADAM8 may be a potential target of antiangiogenic therapy for HCC.

Increased microglia/macrophage gene expression in a subset of adult and pediatric astrocytomas

Glioblastoma (GBM) is a highly malignant brain tumor with a dismal prognosis. Gene expression profiling of GBM has revealed clinically relevant tumor subtypes, and this provides exciting opportunities to better understand disease pathogenesis. Results from an increasing number of studies demonstrate a role for the immune response in cancer progression, yet it is unclear how the immune response differs across tumor subtypes and how it affects outcome. Utilizing gene expression data from The Cancer Genome Atlas Project and the Gene Expression Omnibus database, we demonstrate an enrichment of immune response-related gene expression in the mesenchymal subtype of adult GBM (n = 173) and pediatric high-grade gliomas (n = 53). In an independent cohort of pediatric astrocytomas (n = 24) from UCSF, we stratified tumors into subtypes and confirmed these findings. Using novel immune cell-specific gene signatures we demonstrate selective enrichment of microglia/macrophage-related genes in adult and pediatric GBM tumors of the mesenchymal subtype. Furthermore, immunostaining of adult GBM tumors showed significantly higher cell numbers of microglia/macrophages in mesenchymal versus non-mesenchymal tumors (p = 0.04). Interestingly, adult GBM tumors with the shortest survival had significant enrichment of microglia/macrophage-related genes but this was not true for pediatric GBMs. Consistent with an association with poor outcome, immune response-related genes were highly represented in an adult poor prognosis gene signature, with the expression of genes related to macrophage recruitment and activation being most strongly associated with survival (p<0.05) using CoxBoost multivariate modeling. Using a microglia/macrophage high gene signature derived from quantification of tumor-infiltrating cells in adult GBM, we identified enrichment of genes characteristic of CD4 T cells, granulocytes, and microglia/macrophages (n = 573). These studies support a role for the immune response, particularly the microglia/macrophage response, in the biology of an important subset of GBM. Identification of this subset may be important for future therapeutic stratification.

High expression of ADAM8 correlates with poor prognosis in hepatocellular carcinoma

OBJECTIVES

To evaluate the association between ADAM8 tissue expression and patient prognosis in hepatocellular carcinoma (HCC).

METHODS

ADAM8 expression was analyzed using immunohistochemical staining methods on tissue samples from a consecutive series of 105 HCC patients who underwent resections between 2000 and 2006. The correlation of ADAM8 expression and patients' clinicopathological parameters was evaluated. Survival analysis was performed using the Kaplan-Meier method and Cox's proportional hazards model.

RESULTS

ADAM8 was highly expressed in 54.3% of the HCC patients. The ADAM8 expression level was closely associated with serum AFP elevation, tumor size, histological differentiation, tumor recurrence, tumor metastasis, and tumor stage. Kaplan-Meier survival analysis showed that a high expression level of ADAM8 resulted in a significantly poor prognosis of HCC patients. Multivariate analysis revealed that ADAM8 expression level was an independent prognostic parameter for the overall survival rate of HCC patients.

CONCLUSIONS

These findings provide evidence that a high expression level of ADAM8 serves as a biomarker for poor prognosis for HCC. Thus, we speculate that ADAM8 may be a potential target of antiangiogenic therapy for HCC.

Merlin: the wizard requires protein stability to function as a tumor suppressor

Neurofibromatosis type 2 (NF2), characterized by tumors of the nervous system, is a result of functional loss of the NF2 gene. The NF2 gene encodes Merlin (moesin-ezrin-radixin-like protein), an ERM (Ezrin, Radixin, Moesin) protein family member. Merlin functions as a tumor suppressor through impacting mechanisms related to proliferation, apoptosis, survival, motility, adhesion, and invasion. Several studies have summarized the tumor intrinsic mutations in Merlin. Given the fact that tumor cells are not in isolation, but rather in an intricate, mutually sustaining synergy with their surrounding stroma, the dialog between the tumor cells and the stroma can potentially impact the molecular homeostasis and promote evolution of the malignant phenotype. This review summarizes the epigenetic modifications, transcript stability, and post-translational modifications that impact Merlin. We have reviewed the role of extrinsic factors originating from the tumor milieu that influence the availability of Merlin inside the cell. Information regarding Merlin regulation could lead to novel therapeutics by stabilizing Merlin protein in tumors that have reduced Merlin protein expression without displaying any NF2 genetic alterations.