Periostin promotes invasiveness and resistance of pancreatic cancer cells to hypoxia-induced cell death: role of the beta4 integrin and the PI3k pathway

Deletion of cysteine cathepsins B or L yields differential impacts on murine skin proteome and degradome

Numerous studies highlight the fact that concerted proteolysis is essential for skin morphology and function. The cysteine protease cathepsin L (Ctsl) has been implicated in epidermal proliferation and desquamation, as well as in hair cycle regulation. In stark contrast, mice deficient in cathepsin B (Ctsb) do not display an overt skin phenotype. To understand the systematic consequences of deleting Ctsb or Ctsl, we determined the protein abundances of >1300 proteins and proteolytic cleavage events in skin samples of wild-type, Ctsb(-/-), and Ctsl(-/-) mice via mass-spectrometry-based proteomics. Both protease deficiencies revealed distinct quantitative changes in proteome composition. Ctsl(-/-) skin revealed increased levels of the cysteine protease inhibitors cystatin B and cystatin M/E, increased cathepsin D, and an accumulation of the extracellular glycoprotein periostin. Immunohistochemistry located periostin predominantly in the hypodermal connective tissue of Ctsl(-/-) skin. The proteomic identification of proteolytic cleavage sites within skin proteins revealed numerous processing sites that are underrepresented in Ctsl(-/-) or Ctsb(-/-) samples. Notably, few of the affected cleavage sites shared the canonical Ctsl or Ctsb specificity, providing further evidence of a complex proteolytic network in the skin. Novel processing sites in proteins such as dermokine and Notch-1 were detected. Simultaneous analysis of acetylated protein N termini showed prototypical mammalian N-alpha acetylation. These results illustrate an influence of both Ctsb and Ctsl on the murine skin proteome and degradome, with the phenotypic consequences of the absence of either protease differing considerably.

Reversing effect of ring finger protein 43 inhibition on malignant phenotypes of human hepatocellular carcinoma

It has been shown that Ring finger protein 43 (RNF43) is overexpressed in colorectal cancer and mediates cancer cell proliferation; however, its role in hepatocellular carcinoma (HCC) remains unknown. In this study, we found that RNF43 was frequently overexpressed in HCCs, and this overexpression was correlated with positive vascular invasion, poor tumor differentiation, and advanced tumor stage. Functional studies showed that knockdown of RNF43 could induce apoptosis and inhibit proliferation, invasion, colony formation, and xenograft growth of HCCs. Microarray-based gene profiling showed a total of 229 genes differentially expressed after RNF43 knockdown, many of which are involved in oncogenic processes such as cell proliferation, cell adhesion, cell motility, cell death, DNA repair, and so on. These results suggest that RNF43 is involved in tumorigenesis and progression of HCCs and that antagonism of RNF43 may be beneficial for HCC treatment.

Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors

Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer.

Cancer stem cell-related gene periostin: a novel prognostic marker for breast cancer

We investigated the expression status of periostin in breast cancer stem cells and its clinical implications in order to lay a foundation for managing breast cancer. CD44+/CD24−/line- tumor cells (CSC) from clinical specimens were sorted using flow cytometry. Periostin expression status was detected in CSC cells and 1,086 breast cancer specimens by Western blot and immunohistochemistry staining, with the CSC ratio determined by immunofluorescence double staining. The relationship between the periostin protein and clinico-pathological parameters and prognosis was subsequently determined. As a result, CSC cells are more likely to generate new tumors in mice and cell microspheres that are deficient in NOD/SCID compared to the control group. Periostin protein was expressed higher in CSC cells compared to the control cells and was found to be related to CSC chemotherapy resistance. Moreover, periostin expression was found to be related to the CSC ratio in 1,086 breast cancer specimens (P = 0.001). In total, 334 (30.76%) of the 1,086 breast cases showed high periostin expression. After universal and Spearman regression correlation analysis, periostin was observed to be related to histological grade, CSC ratio, lymph node metastasis, tumor size, and triple-negative breast cancer (all P<0.05). Furthermore, periostin was shown to attain a significantly more distant bone metastasis and worse disease-specific survival than those with none or low-expressed periostin protein (P = 0.001). In the Cox regression test, periostin protein was detected as an independent prognostic factor (P = 0.001). In conclusion, periostin was found to be related to the CSC and an independent prognostic factor for breast cancer. It is also perhaps a potential target to breast cancer.

The multifaceted roles of neutrophil gelatinase associated lipocalin (NGAL) in inflammation and cancer

Neutrophil gelatinase associated lipocalin (NGAL), also known as oncogene 24p3, uterocalin, siderocalin or lipocalin 2, is a 24kDa secreted glycoprotein originally purified from a culture of mouse kidney cells infected with simian virus 40 (SV-40). Subsequent investigations have revealed that it is a member of the lipocalin family of proteins that transport small, hydrophobic ligands. Since then, NGAL expression has been reported in several normal tissues where it serves to provide protection against bacterial infection and modulate oxidative stress. Its expression is also dysregulated in several benign and malignant diseases. Its small size, secreted nature and relative stability have led to it being investigated as a diagnostic and prognostic biomarker in numerous diseases including inflammation and cancer. Functional studies, conducted primarily on lipocalin 2 (Lcn2), the mouse homologue of human NGAL have revealed that Lcn2 has a strong affinity for iron complexed to both bacterial siderophores (iron-binding proteins) and certain human proteins like norepinephrine. By sequestering iron-laden siderophores, Lcn2 deprives bacteria of a vital nutrient and thus inhibits their growth (bacteriostatic effect). In malignant cells, its proposed functions range from inhibiting apoptosis (in thyroid cancer cells), invasion and angiogenesis (in pancreatic cancer) to increasing proliferation and metastasis (in breast and colon cancer). Ectopic expression of Lcn2 also promotes BCR-ABL induced chronic myelogenous leukemia in murine models. By transporting iron into and out of the cell, NGAL also regulates iron responsive genes. Further, it stabilizes the proteolytic enzyme matrix metalloprotease-9 (MMP-9) by forming a complex with it, and thereby prevents its autodegradation. The factors regulating NGAL expression are numerous and range from pro-inflammatory cytokines like interleukins, tumor necrosis factor-α and interferons to vitamins like retinoic acid. The purpose of this review article is to examine the expression, structure, regulation and biological role of NGAL and critically assess its potential as a novel diagnostic and prognostic marker in both benign and malignant human diseases.

Periostin is a systemic biomarker of eosinophilic airway inflammation in asthmatic patients

BACKGROUND

Eosinophilic airway inflammation is heterogeneous in asthmatic patients. We recently described a distinct subtype of asthma defined by the expression of genes inducible by T(H)2 cytokines in bronchial epithelium. This gene signature, which includes periostin, is present in approximately half of asthmatic patients and correlates with eosinophilic airway inflammation. However, identification of this subtype depends on invasive airway sampling, and hence noninvasive biomarkers of this phenotype are desirable.

OBJECTIVE

We sought to identify systemic biomarkers of eosinophilic airway inflammation in asthmatic patients.

METHODS

We measured fraction of exhaled nitric oxide (Feno), peripheral blood eosinophil, periostin, YKL-40, and IgE levels and compared these biomarkers with airway eosinophilia in asthmatic patients.

RESULTS

We collected sputum, performed bronchoscopy, and matched peripheral blood samples from 67 asthmatic patients who remained symptomatic despite maximal inhaled corticosteroid treatment (mean FEV(1), 60% of predicted value; mean Asthma Control Questionnaire [ACQ] score, 2.7). Serum periostin levels are significantly increased in asthmatic patients with evidence of eosinophilic airway inflammation relative to those with minimal eosinophilic airway inflammation. A logistic regression model, including sex, age, body mass index, IgE levels, blood eosinophil numbers, Feno levels, and serum periostin levels, in 59 patients with severe asthma showed that, of these indices, the serum periostin level was the single best predictor of airway eosinophilia (P = .007).

CONCLUSION

Periostin is a systemic biomarker of airway eosinophilia in asthmatic patients and has potential utility in patient selection for emerging asthma therapeutics targeting T(H)2 inflammation.

Periostin facilitates skin sclerosis via PI3K/Akt dependent mechanism in a mouse model of scleroderma

Objective

Periostin, a novel matricellular protein, is recently reported to play a crucial role in tissue remodeling and is highly expressed under fibrotic conditions. This study was undertaken to assess the role of periostin in scleroderma.

Methods

Using skin from patients and healthy donors, the expression of periostin was assessed by immunohistochemistry and immunoblotting analyses. Furthermore, we investigated periostin^−/− (PN^−/−) and wild-type (WT) mice to elucidate the role of periostin in scleroderma. To induce murine cutaneous sclerosis, mice were subcutaneously injected with bleomycin, while untreated control groups were injected with phosphate-buffered saline. Bleomycin-induced fibrotic changes were compared in PN^−/− and WT mice by histological analysis as well as by measurements of profibrotic cytokine and extracellular matrix protein expression levels in vivo and in vitro. To determine the downstream pathway involved in periostin signaling, receptor neutralizing antibody and signal transduction inhibitors were used in vitro.

Results

Elevated expression of periostin was observed in the lesional skin of patients with scleroderma compared with healthy donors. Although WT mice showed marked cutaneous sclerosis with increased expression of periostin and increased numbers of myofibroblasts after bleomycin treatment, PN^−/− mice showed resistance to these changes. In vitro, dermal fibroblasts from PN^−/− mice showed reduced transcript expression of alpha smooth actin and procollagen type-I alpha 1 (Col1α1) induced by transforming growth factor beta 1 (TGFβ1). Furthermore, recombinant mouse periostin directly induced Col1α1 expression in vitro, and this effect was inhibited by blocking the αv integrin-mediated PI3K/Akt signaling either with anti-αv functional blocking antibody or with the PI3K/Akt kinase inhibitor LY294002.

Conclusion

Periostin plays an essential role in the pathogenesis of Bleomycin-induced scleroderma in mice. Periostin may represent a potential therapeutic target for human scleroderma.

Periostin as a biomarker of the amniotic membrane

Tracing the precise developmental origin of amnion and amnion-derived stem cells is still challenging and depends chiefly on analyzing powerful genetic model amniotes like mouse. Profound understanding of the fundamental differences in amnion development in both the disc-shaped primate and human embryo and the cup-shaped mouse embryo is pivotal in particular when sampling amniotic membrane from nonprimate species for isolating candidate amniotic stem cells. The availability of molecular marker genes that are specifically expressed in the amniotic membrane and not in other extraembryonic membranes would be instrumental to validate unequivocally the starting material under investigation. So far such amniotic markers have not been reported. We postulated that bone morphogenetic protein (BMP) target genes are putative amniotic membrane markers mainly because deficiency in one of several components of the BMP signaling cascade in mice has been documented to result in defective development of the early amnion. Comparative gene expression analysis of acknowledged target genes for BMP in different extraembryonic tissues, combined with in situ hybridization, identified Periostin (Postn) mRNA enrichment in amnion throughout gestation. In addition, we identify and propose a combination of markers as transcriptional signature for the different extraembryonic tissues in mouse.

Functional significance of periostin in excisional skin repair: is the devil in the detail?

In the past year, three papers have been published exploring the role of the matricellular protein periostin in excisional skin repair. These papers all show a delay in wound closure and the kinetics of this delay are strikingly similar across the three reports. The similarities between these papers end, however, when each investigates the mechanism through which periostin influences skin repair. Three proposed mechanisms have been identified: (1) myofibroblast differentiation, (2) keratinocyte proliferation and (3) fibroblast proliferation and migration. The aim of this commentary is to compare and contrast the three studies performed to date in an attempt to decipher the role of periostin in the repair of full-thickness skin wounds.

Periostin activates integrin α5β1 through a PI3K/AKT‑dependent pathway in invasion of cholangiocarcinoma

Periostin (PN) is mainly produced from stromal fibroblasts in cholangiocarcinoma (CCA) and shows strong impact in cancer promotion. This work aimed to investigate the mechanism that PN uses to drive CCA invasion. It was found that ITGα5β1 and α6β4 showed high expression in non-tumorigenic biliary epithelial cells and in almost all CCA cell lines. PN had preferential binding to CCA cells via ITGα5β1 and blocking this receptor by either neutralizing antibody or siITGα5 could attenuate PN-induced invasion. After PN-ITGα5β1 binding, intracellular pAKT was upregulated whereas there was no change in pERK. Moreover, PN could not activate AKT in condition of treatment with a PI3K inhibitor. These data provide evidence that PN-activated invasion of CCA cells is through the ITGα5β1/PI3K/AKT pathway. Strategies aimed to inhibit this pathway may, thus, provide therapeutic benefits.

Deletion of periostin reduces muscular dystrophy and fibrosis in mice by modulating the transforming growth factor-β pathway

The muscular dystrophies are broadly classified as muscle wasting diseases with myofiber dropout due to cellular necrosis, inflammation, alterations in extracellular matrix composition, and fatty cell replacement. These events transpire and progress despite ongoing myofiber regeneration from endogenous satellite cells. The degeneration/regeneration response to muscle injury/disease is modulated by the proinflammatory cytokine transforming growth factor-β (TGF-β), which can also profoundly influence extracellular matrix composition through increased secretion of profibrotic proteins, such as the matricellular protein periostin. Here we show that up-regulation and secretion of periostin is pathological and enhances disease in the δ-sarcoglycan null (Sgcd(-/-)) mouse model of muscular dystrophy (MD). Indeed, MD mice lacking the Postn gene showed dramatic improvement in skeletal muscle structure and function. Mechanistically, Postn gene deletion altered TGF-β signaling so that it now enhanced tissue regeneration with reduced levels of fibrosis. Systemic antagonism of TGF-β with a neutralizing monoclonal antibody mitigated the beneficial effects of Postn deletion in vivo. These data suggest that periostin functions as a disease determinant in MD by promoting/allowing the pathological effects of TGF-β, suggesting that inhibition of periostin could represent a unique treatment approach.

Periostin, a stroma-associated protein, correlates with tumor invasiveness and progression in nasopharyngeal carcinoma

Recently, the tumor microenvironment is increasingly recognized as playing an important role in cancer proliferation, invasion, and metastasis. To screen stroma-associated proteins involved in nasopharyngeal carcinoma (NPC) carcinogenesis, laser capture microdissection (LCM) and quantitative proteomic analysis were employed to assess different protein expression of the stroma between NPC and normal nasopharyngeal mucosa (NNM). In this study, periostin was identified to be significantly up-regulated in NPC stroma compared with NNM stroma and the result was further confirmed by Western blotting. Immunohistochemistry showed that over-expression of periostin was frequently observed in the stroma of NPC and matched lymph node metastases (LNM) compared with the stroma of NNM. Statistical analysis showed over-expression of periostin was significantly associated with advanced clinical stage (P < 0.001) and lymph node metastasis (P < 0.001) and decreased overall survival (P < 0.001) in NPC. Cox regression analysis indicated over-expression of periostin was an independent prognostic factor. Furthermore, ectopic expression of periostin was used to examine its effect on invasiveness of NPC cell in vitro and the result showed that periostin was able to promote invasiveness of NPC cell. In conclusion, periostin expression is correlated with tumor stage, lymph node metastasis, and patient survival. Periostin is a potential biomarker for the differentiation and prognosis of NPC, and it might play an important role in the progression of NPC.

ß3 integrin modulates transforming growth factor beta induced (TGFBI) function and paclitaxel response in ovarian cancer cells

Background

The extracellular matrix (ECM) has a key role in facilitating the progression of ovarian cancer and we have shown recently that the secreted ECM protein TGFBI modulates the response of ovarian cancer to paclitaxel-induced cell death.

Results

We have determined TGFBI signaling from the extracellular environment is preferential for the cell surface αvß3 integrin heterodimer, in contrast to periostin, a TGFBI paralogue, which signals primarily via a ß1 integrin-mediated pathway. We demonstrate that suppression of ß1 integrin expression, in ß3 integrin-expressing ovarian cancer cells, increases adhesion to rTGFBI. In addition, Syndecan-1 and −4 expression is dispensable for adhesion to rTGFBI and loss of Syndecan-1 cooperates with the loss of ß1 integrin to further enhance adhesion to rTGFBI. The RGD motif present in the carboxy-terminus of TGFBI is necessary, but not sufficient, for SKOV3 cell adhesion and is dispensable for adhesion of ovarian cancer cells lacking ß3 integrin expression. In contrast to TGFBI, the carboxy-terminus of periostin, lacking a RGD motif, is unable to support adhesion of ovarian cancer cells. Suppression of ß3 integrin in SKOV3 cells increases resistance to paclitaxel-induced cell death while suppression of ß1 integrin has no effect. Furthermore, suppression of TGFBI expression stimulates a paclitaxel resistant phenotype while suppression of fibronectin expression, which primarily signals through a ß1 integrin-mediated pathway, increases paclitaxel sensitivity.

Conclusions

Therefore, different ECM components use distinct signaling mechanisms in ovarian cancer cells and in particular, TGFBI preferentially interacts through a ß3 integrin receptor mediated mechanism to regulate the response of cells to paclitaxel-induced cell death.

Gene expression changes associated with the progression of intraductal papillary mucinous neoplasms

OBJECTIVES

The diagnosis of high-grade intraductal papillary mucinous neoplasm (IPMN) is difficult to distinguish from low-grade IPMN. The aim of this study was to identify potential markers for the discrimination of high-grade and invasive (HgInv) IPMN from low- and moderate-grade dysplasia IPMN.

METHODS

Laser capture microdissection was used to isolate distinct foci of low-grade, moderate-grade, high-grade, and invasive IPMN from paraffin-embedded archival tissue from 14 patients who underwent resection for IPMN. Most samples included multiple grades in the same specimen. Affymetrix Human Exon microarrays were used to compare low- and moderate-grade dysplasia IPMN with HgInv IPMN.

RESULTS

Sixty-two genes were identified as showing significant changes in expression (P ≤ 0.05 and a 2-fold cutoff), including up-regulation of 41 in HgInv IPMN. Changes in gene expression are associated with biological processes related to malignant behavior including cell motion, cell proliferation, response to hypoxia, and epithelial-to-mesenchymal transition. In addition, altered signaling in several transforming growth factor β-related pathways was exhibited in the progression of IPMN to malignancy.

CONCLUSIONS

This study identifies a set of genes associated with the progression of IPMN to malignancy. These genes are potential markers that could be used to identify IPMN requiring surgical resection.

The multiple facets of periostin in bone metabolism

Periostin is a matricellular glutamate-containing protein expressed during ontogenesis and in adult connective tissues submitted to mechanical strains including bone and, more specifically, the periosteum, periodontal ligaments, tendons, heart valves, or skin. It is also expressed in neoplastic tissues, cardiovascular and fibrotic diseases, and during wound repair. Its biological functions are extensively investigated in fields such as cardiovascular physiology or oncology. Despite its initial identification in bone, investigations of periostin functions in bone-related physiopathology are less abundant. Recently, several studies have analyzed the potential role of periostin in bone biology and suggest that periostin may be an important regulator of bone formation. The aim of this article is to provide an extensive review on the implications of periostin in bone biology and its potential use in benign and metabolic bone diseases.

Periostin: a putative mediator involved in tumour resistance to anti-angiogenic therapy?

Despite advances in the development of anti-angiogenic agents for cancer treatment, the increase in the survival duration of cancer patients is still rather modest. One major obstacle in anti-angiogenic therapy is the emergence of drug resistance. Understanding the molecular mechanisms that enable a tumour to evade anti-angiogenic treatment is valuable to improve therapeutic efficacy. Targeting blood supply usually causes hypoxic responses of tumours that trigger a series of adaptive changes leading to a resistant phenotype. Periostin, a secreted ECM (extracellular matrix) protein, is mainly produced by CAFs (cancer-associated fibroblasts) on hypoxic stress. As CAFs have been casually linked to tumour resistance to angiogenesis blockade and periostin can influence many aspects of tumour biology, we hypothesized that periostin might be a crucial mediator involved anti-angiogenic resistance in cancer treatment. This hypothesis is indirectly supported by the following facts: (a) high levels of periostin promote tumour angiogenesis; (b) periostin improves cancer cell survival under hypoxic conditions; and (c) genetic modulation of periostin induces EMT (epithelial-mesenchymal transition) and enhances cancer cell invasion and metastasis, which represents an escape mechanism from anticancer treatment. Testing and confirmation of this hypothesis will give more insight into the resistance mechanisms and provide the rationale for improvement of therapeutic outcome of anti-angiogenic therapy.

Periostin modulates myofibroblast differentiation during full-thickness cutaneous wound repair

The matricellular protein periostin is expressed in the skin. Although periostin has been hypothesized to contribute to dermal homeostasis and repair, this has not been directly tested. To assess the contribution of periostin to dermal healing, 6 mm full-thickness excisional wounds were created in the skin of periostin-knockout and wild-type, sex-matched control mice. In wild-type mice, periostin was potently induced 5-7 days after wounding. In the absence of periostin, day 7 wounds showed a significant reduction in myofibroblasts, as visualized by expression of α-smooth muscle actin (α-SMA) within the granulation tissue. Delivery of recombinant human periostin by electrospun collagen scaffolds restored α-SMA expression. Isolated wild-type and knockout dermal fibroblasts did not differ in in vitro assays of adhesion or migration; however, in 3D culture, periostin-knockout fibroblasts showed a significantly reduced ability to contract a collagen matrix, and adopted a dendritic phenotype. Recombinant periostin restored the defects in cell morphology and matrix contraction displayed by periostin-deficient fibroblasts in a manner that was sensitive to a neutralizing anti-β1-integrin and to the FAK and Src inhibitor PP2. We propose that periostin promotes wound contraction by facilitating myofibroblast differentiation and contraction.

The role of cancer-associated myofibroblasts in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma is typically characterized by a dense desmoplastic stroma, of which cancer-associated myofibroblasts (which express α-smooth muscle actin), are a major cellular component. These stromal myofibroblasts have a crucial role in accelerating the progression of intrahepatic cholangiocarcinoma and in promoting resistance to therapy through interactive autocrine and paracrine signaling pathways that promote malignant cell proliferation, migration, invasiveness, apoptosis resistance and/or epithelial-mesenchymal transition. These changes correlate with aggressive tumor behavior. Hypoxic desmoplasia and aberrant Hedgehog signaling between stromal myofibroblastic cells and cholangiocarcinoma cells are also critical modulators of intrahepatic cholangiocarcinoma progression and therapy resistance. A novel strategy has been developed to achieve improved therapeutic outcomes in patients with advanced intrahepatic cholangiocarcinoma, based on targeting of multiple interactive pathways between cancer-associated myofibroblasts and intrahepatic cholangiocarcinoma cells that are associated with disease progression and poor survival. Unique organotypic cell culture and orthotopic rat models of cholangiocarcinoma progression are well suited to the rapid preclinical testing of this potentially paradigm-shifting strategy.

The role of cancer-associated myofibroblasts in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma is typically characterized by a dense desmoplastic stroma, of which cancer-associated myofibroblasts (which express α-smooth muscle actin), are a major cellular component. These stromal myofibroblasts have a crucial role in accelerating the progression of intrahepatic cholangiocarcinoma and in promoting resistance to therapy through interactive autocrine and paracrine signaling pathways that promote malignant cell proliferation, migration, invasiveness, apoptosis resistance and/or epithelial-mesenchymal transition. These changes correlate with aggressive tumor behavior. Hypoxic desmoplasia and aberrant Hedgehog signaling between stromal myofibroblastic cells and cholangiocarcinoma cells are also critical modulators of intrahepatic cholangiocarcinoma progression and therapy resistance. A novel strategy has been developed to achieve improved therapeutic outcomes in patients with advanced intrahepatic cholangiocarcinoma, based on targeting of multiple interactive pathways between cancer-associated myofibroblasts and intrahepatic cholangiocarcinoma cells that are associated with disease progression and poor survival. Unique organotypic cell culture and orthotopic rat models of cholangiocarcinoma progression are well suited to the rapid preclinical testing of this potentially paradigm-shifting strategy.

Enhancement of MSC adhesion and therapeutic efficiency in ischemic heart using lentivirus delivery with periostin

Many approaches have shown beneficial effects of modified mesenchymal stem cells (MSCs) for treatment of infarcted myocardium, but have primarily focused on enhancing the survival of transplanted MSCs. Here, we show the dual benefits of periostin-overexpressing MSCs (p-MSCs) for infarcted myocardium. P-MSCs led to the marked histological and functional recovery of infarcted myocardium by enhancing survival of MSCs and directly preventing apoptosis of cardiomyocytes. Survival of p-MSCs themselves and cardiomyocytes co-cultured with p-MSCs or treated with the conditioned media from p-MSCs was significantly increased under hypoxic conditions. Decreases in adhesion-related integrins were reversed in cardiomyocytes co-cultured with p-MSCs, followed by increases in p-PI3K and Akt, indicating that periostin activates the PI3K pathway through adhesion-related integrins. When p-MSCs were injected into myocardial infarcted rats, histological pathology and cardiac function were significantly improved compared to MSC-injected controls. Thus, periostin might be a new target of therapeutic treatments using MSCs as carriers for infarcted myocardium.

Characterization of periostin isoform pattern in non-small cell lung cancer

INTRODUCTION

The extracellular matrix N-glycoprotein periostin (OSF-2, POSTN) is a major constituent of the desmoplastic stroma around solid tumors. It promotes tumor invasion and metastasis via epithelial-mesenchymal transition (EMT). In this study we investigated periostin expression at both RNA and protein level as well as the expression pattern of its splice isoforms in non-small cell lung cancer (NSCLC).

METHODS

Thirty fresh frozen and corresponding formalin-fixed NSCLC tissues (adeno- and squamous cell carcinoma subtype, each n=15) and their matched non-neoplastic tissues were investigated. Periostin mRNA levels were analyzed by quantitative RT-PCR. The EMT-markers periostin and vimentin were analyzed by immunohistochemistry. Laser capture microdissection allowed for analysis of periostin expression in tumor epithelia and stroma, separately. Isoform patterns were investigated by isoform-specific PCR following sequencing in NSCLC, fetal and adult normal lung tissue.

RESULTS

The qRT-PCR analysis showed periostin mRNA up-regulation in NSCLC tissue in relation to normal lung, with significantly higher levels in the adeno-compared to the squamous cell subtype (p<0.05). However, protein levels in both tumor epithelia and stroma correlated with squamous cell carcinoma (p<0.001) and larger tumor size (p<0.05). Further, periostin tumor epithelia expression, correlated with higher tumor grade (p<0.05). Sequence analysis detected eight periostin isoforms in fetal lung, but only five in both NSCLC and matched normal lung tissue. Among the eight isoforms, four are new and were labelled 5, 7, 8 and 9. The exclusive presence of isoforms 1 and 9 in fetal tissue suggests splice-specific regulation during lung embryogenesis. Finally, laser capture microdissection demonstrated that both tumor epithelia and stromal cells can be a source of periostin production in NSCLC.

CONCLUSIONS

This study represents the first analysis of periostin isoform expression patterns in NSCLC and a characterization of periostin expression in cancer versus stromal cells at both RNA and protein level.

Periostin expression and epithelial-mesenchymal transition in cancer: a review and an update

Periostin, also called osteoblast-specific factor 2, is a secreted cell adhesion protein, which shares a homology with the insect cell adhesion molecule fasciclin I. It has been shown to be an important regulator of bone and tooth formation and maintenance, and of cardiac development and healing. Recent studies revealed that periostin plays an important role in tumor development and is upregulated in a wide variety of cancers such as colon, pancreatic, ovarian, breast, head and neck, thyroid, and gastric cancer as well as in neuroblastoma. Periostin binding to the integrins activates the Akt/PKB- and FAK-mediated signaling pathways which lead to increased cell survival, angiogenesis, invasion, metastasis, and importantly, epithelial-mesenchymal transition of carcinoma cells. In this review we summarize recent clinicopathological studies that have investigated periostin expression in lung, kidney, prostate, liver cancer, and malignant pleural mesothelioma and discuss the role of periostin isoforms in tumorigenesis and their potential as targets for stroma-targeted anticancer therapy.

PERIOSTIN regulates MMP-2 expression via the αvβ3 integrin/ERK pathway in human periodontal ligament cells

OBJECTIVE

During orthodontic tooth movement, activation of the vascular system in the compressed periodontal ligament (PDL), which becomes hypoxic, is essential for periodontal tissue remodelling. PERIOSTIN, an extracellular matrix protein, is expressed in PDL and its concentration is increased on the compressive side during orthodontic tooth movement. PERIOSTIN promotes angiogenesis through upregulation of matrix metalloproteinase (MMP)-2, which has been shown to be expressed via αvβ3 integrin/extracellular signal-related kinase (ERK) signalling pathway and vascular endothelial growth factor (VEGF). Therefore, we hypothesized that hypoxia-induced PERIOSTIN promotes MMP-2 expression via αvβ3 integrin/ERK signalling and VEGF in PDL cells.

METHODS

Human PDL cells were cultured in condition medium containing desferrioxamine (DFO) to mimic hypoxia. The total RNA, cell lysates or supernatant were collected, and MMP2 and VEGF expression, PERIOSTIN expression and ERK phosphorylation, and MMP-2 activity were analysed by real-time RT-PCR, western blot analysis, and zymography, respectively. A recombinant human PERIOSTIN or PERIOSTIN siRNA was applied to the cells, then the total RNA was extracted to measure MMP-2 and VEGF expression. The cells were treated with αvβ3 integrin-blocking antibody or ERK inhibitor followed by PERIOSTIN stimulation. MMP-2 expression was measured by real-time RT-PCR.

RESULTS

PERIOSTIN was upregulated in a time-dependent manner in human PDL cells treated with DFO, a chemical hypoxia mimic. MMP-2 and VEGF expression, and MMP-2 activity were increased by DFO or PERIOSTIN treatment, and decreased by PERIOSTIN silencing. PERIOSTIN treatment also induced ERK phosphorylation, and PERIOSTIN-induced MMP-2 was reduced by αvβ3 integrin-blocking antibody or ERK inhibitor.

CONCLUSION

These data suggest that PERIOSTIN upregulates MMP-2 expression via the αvβ3 integrin/ERK signalling pathway and VEGF expression in human PDL cells.

Expression patterns and roles of periostin during kidney and ureter development

PURPOSE

Periostin is a secreted extracellular matrix protein that is differentially expressed in the developing kidney. We analyzed the temporal-spatial expression of periostin in the developing kidney and ureter as well as its roles in ureter branching morphogenesis, nephrogenesis and ureter development.

MATERIALS AND METHODS

RNA in situ hybridization and immunofluorescence histochemistry were used to investigate the expression of periostin, αv integrin and α-smooth muscle actin during mouse renal and ureteral development. Metanephric explants were cultured in the presence of recombinant periostin, and ureteral branch points/tips and the glomerular number were quantified. Explants were also cultured in the presence of exogenous bone morphogenetic protein 4 and the effect on periostin mRNA levels was determined by quantitative real-time polymerase chain reaction.

RESULTS

Periostin expression was observed in the mesenchyme surrounding the kidney and ureter, renal stroma, metanephric mesenchyme, ureter epithelium and developing nephrons. At embryonic day 15.5 periostin and αv integrin, a common subunit of periostin receptors, were co-expressed in smooth muscle cells of the ureter, renal artery and intrarenal arteries. Bone morphogenetic protein 4 up-regulated periostin mRNA expression and exogenous periostin inhibited branching morphogenesis and glomerular number.

CONCLUSIONS

Bone morphogenetic protein 4 which inhibits ureteral branching morphogenesis and promotes smooth muscle cell migration in the ureter up-regulated periostin mRNA expression in the developing kidney. Ureteral smooth muscle cells express periostin and αv integrin. Periostin inhibited ureteral branching morphogenesis and glomerular number. Together these results suggest that periostin and bone morphogenetic protein 4 may have a role in branching morphogenesis, nephrogenesis and possibly smooth muscle cell migration.

Relevance of periostin splice variants in renal cell carcinoma

The extracellular matrix N-glycoprotein periostin is thought to enhance tumor invasion. In this study, the expression patterns of periostin and its splice isoforms were investigated in renal cell carcinoma (RCC). Periostin mRNA expression patterns were characterized in 30 fresh-frozen RCCs in normal fetal and adult renal tissues by both isoform-specific and nonspecific RT-PCR and by gene expression array analysis. Its protein expression was analyzed by immunohistochemistry, using tissue microarrays with tissue from 1007 RCC patients. Periostin mRNA in RCC was increased, as observed in both RT-PCR and gene microarray analyses, with significantly higher expression in the clear cell than in the papillary subtype. Four of eight periostin isoforms, identified in fetal kidney by direct sequencing, have not been described to date. Three isoforms could be detected in both RCC and matched non-neoplastic tissue, and one of them was expressed more frequently in RCC. Periostin protein was detected in both mesenchymal cells of the tumor stroma and epithelial tumor cells. Greater amounts of periostin in tumor epithelia correlated with the presence of sarcomatoid differentiation, higher tumor stage, lymph node metastases, and poor overall survival in the clear cell subtype. In conclusion, periostin expression in tumor epithelia may contribute to sarcomatoid differentiation and more aggressive behavior of RCC. The presence of a tumor-associated periostin isoform suggests splice-specific regulation in RCC tissue.

Periostin as a heterofunctional regulator of cardiac development and disease

Periostin (Postn) is a heterofunctional secreted extracellular matrix (ECM) protein comprised of four fasciclin domains that promotes cellular adhesion and movement, as well as collagen fibrillogenesis. Postn is expressed in unique growth centers during embryonic development where it facilitates epithelial-mesenchymal transition (EMT) of select cell populations undergoing reorganization. In the heart, Postn is expressed in the developing valves, cardiac fibroblasts and in regions of the outflow track. In the adult, Postn expression is specifically induced in areas of tissue injury or areas with ongoing cellular re-organization. In the adult heart Postn is induced in the ventricles following myocardial infarction, pressure overload stimulation, or generalized cardiomyopathy. Here we will review the functional consequences associated with Postn induction in both the developing and adult heart. The majority of data collected to date suggest a common function for Postn in both development and disease as a potent inducible regulator of cellular reorganization and extracellular matrix homeostasis, although some alternate and controversial functions have also been ascribed to Postn, the validity of which will be discussed here.

Periostin: a promising target of therapeutical intervention for prostate cancer

Background

In our recent study, Periostin was up-regulated in prostate cancer(PCa) compared with benign prostate hyperplasia (BPH) by proteomics analysis of prostate biopsies. We investigated the effect of sliencing Periostin by RNA interference (RNAi) on the proliferation and migration of PCa LNCap cell line.

Methods

All the prostate biopsies from PCa, BPH and BPH with local prostatic intraepithelial neoplasm(PIN) were analyzed by iTRAQ(Isobaric tags for relative and absolute quantification) technology. Western blotting and immunohistochemical staining were used to verify Periostin expression in the tissues of PCa. Periostin expression in different PCa cell lines was determined by immunofluorescence staining, western blotting and reverse transcription PCR(RT-PCR). The LNCap cells with Periostin expression were used for transfecting shRNA-Periostin lentiviral particles. The efficancy of transfecting shRNA lentiviral particles was evaluated by immunofluorescence, western blotting and Real-time PCR. The effect of silencing Periostin expression by RNAi on proliferation of LNCap cells was determined by MTT assay and tumor xenografts. The tissue slices from theses xenografts were analyzed by hematoxylin and eosin(HE) staining. The expression of Periostin in the xenografts was deteminned by Immunohistochemical staining and western blotting. The migration of LNCap cells after silencing Periostin gene expression were analyzed in vitro.

Results

Periostin as the protein of interest was shown 9.12 fold up-regulation in PCa compared with BPH. The overexpression of Periostin in the stroma of PCa was confirmed by western blotting and immunohistochemical staining. Periostin was only expressed in PCa LNCap cell line. Our results indicated that the transfection ratio was more than 90%. As was expected, both the protein level and mRNA level of Periostin in the stably expressing shRNA-Periostin LNCap cells were significantly reduced. The stably expressing shRNA-Periostin LNCap cells growed slowly in vitro and in vivo. The tissues of xenografts as PCa were verificated by HE staining. Additionally, the weak positive Periostin expressed tumor cells could be seen in the tissues of 6 xenografts from the group of down-regulated Periostin LNCap cells which had a significant decrease of the amount of Periostin compared to the other two group. Furthermore, our results demonstrated that sliencing Periostin could inhibit migration of LNCap cells in vitro.

Conclusions

Our data indicates that Periostin as an up-regulated protein in PCa may be a promising target of therapeutical intervention for PCa in future.

Neutralizing monoclonal antibody to periostin inhibits ovarian tumor growth and metastasis

Periostin, an extracellular matrix protein, is reported to be overexpressed in a variety of human cancers and its functions seem to be linked to tumor metastasis. Our previous results show that engineered periostin overexpression promotes ovarian tumor growth and dissemination in vivo. In this study, we developed a neutralizing monoclonal antibody to periostin, named MZ-1, and investigated its effects on human ovarian tumor growth and metastasis. Our in vivo studies showed significant growth inhibition by MZ-1 on both subcutaneous and intraperitoneal (i.p.) tumors derived from the periostin-expressing ovarian cancer cell line A2780. In addition, MZ-1 treatment led to a reduction of the metastatic potential of these A2780 i.p. tumors. The in vivo antitumor effects of MZ-1 were linked to its specific inhibition of anchorage-independent growth and survival of periostin-expressing cells, as well as its neutralizing effects on periostin-induced cancer cell migration and invasion. The data suggest that blocking periostin expression may be a novel approach for treating the subset of invasive ovarian tumors that overexpress periostin protein.

Enhanced proliferation, invasion, and epithelial-mesenchymal transition of nicotine-promoted gastric cancer by periostin

AIM: To investigate the contribution of periostin in nicotine-promoted gastric cancer cell proliferation, survival, invasion, drug resistance, and epithelial-mesenchymal transition (EMT).

METHODS: Gastric cancer cells were treated with nicotine and periostin protein expression was determined by immunoblotting. Periostin mRNA in gastric cancer cells was silenced using small interfering RNA (siRNA) techniques and periostin gene expression was evaluated by quantitative reverse transcription-polymerase chain reaction. Gastric cancer cells transfected with control or periostin siRNA plasmid were compared in terms of cell proliferation using the methylthiazolyldiphenyl-tetrazolium bromide assay. Cell apoptosis was compared using annexin V-fluoresceine isothiocyanate and propidium iodine double staining. Tumor invasion was determined using the Boyden chamber invasion assay, and the EMT marker Snail expression was evaluated by immunoblotting.

RESULTS: Nicotine upregulated periostin in gastric cancer cells through a COX-2 dependent pathway, which was blocked by the COX-2-specific inhibitor NS398. Periostin mRNA expression was decreased by ~87.2% by siRNA in gastric cancer cells, and stable periostin-silenced cells were obtained by G418 screening. Periostin-silenced gastric cancer cells exhibited reduced cell proliferation, elevated sensitivity to chemotherapy with 5-fluorouracil, and decreased cell invasion and Snail expression (P < 0.05).

CONCLUSION: Periostin is a nicotine target gene in gastric cancer and plays a role in gastric cancer cell growth, invasion, drug resistance, and EMT facilitated by nicotine.

Identification of a novel cell binding site of periostin involved in tumour growth

INTRODUCTION

Periostin (PN), a member of the fasciclin family of proteins, is a TGF-β-induced extracellular matrix protein involved in cell survival, angiogenesis, invasion and metastasis. It is considered a potent angiogenic factor and a marker of tumour progression in many types of human cancer. Many different kinds of cells bind to PN by means of the integrins αvβ3 and αvβ5, but the periostin epitope recognised by these integrins is not formally demonstrated. The aim of our study was to identify which domain of PN could be involved in cell adhesion and its potential role in tumour growth.

METHODS

We generated the monoclonal antibody OC-20 (mAb OC-20) by hybridoma technology. Different PN recombinant fragments were used to characterise the periostin epitope recognised by the mAb OC-20 and to localise a new cell binding site of the protein. A murine model of human melanoma was used in the preclinical in vivo experiments.

RESULTS

We formally demonstrate that the periostin epitope recognised by OC-20 is a new binding site for the integrins αvβ3 and αvβ5, localised in the second FAS1 domain (FAS1-2) of the protein. Moreover the in vivo use of this antibody significantly inhibits tumour growth and angiogenesis.

CONCLUSION

Our results show that the FAS1-2 domain of PN plays a role in tumour progression. Moreover this novel antibody may likewise prove to be very useful in clarifying the role of PN in angiogenesis and may contribute to the design of novel anti-angiogenesis drugs.

Identification of prognostic molecular features in the reactive stroma of human breast and prostate cancer

Primary tumor growth induces host tissue responses that are believed to support and promote tumor progression. Identification of the molecular characteristics of the tumor microenvironment and elucidation of its crosstalk with tumor cells may therefore be crucial for improving our understanding of the processes implicated in cancer progression, identifying potential therapeutic targets, and uncovering stromal gene expression signatures that may predict clinical outcome. A key issue to resolve, therefore, is whether the stromal response to tumor growth is largely a generic phenomenon, irrespective of the tumor type or whether the response reflects tumor-specific properties. To address similarity or distinction of stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to compare the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Invasive breast and prostate cancer-associated stroma was observed to display distinct transcriptomes, with a limited number of shared genes. Interestingly, both breast and prostate tumor-specific dysregulated stromal genes were observed to cluster breast and prostate cancer patients, respectively, into two distinct groups with statistically different clinical outcomes. By contrast, a gene signature that was common to the reactive stroma of both tumor types did not have survival predictive value. Univariate Cox analysis identified genes whose expression level was most strongly associated with patient survival. Taken together, these observations suggest that the tumor microenvironment displays distinct features according to the tumor type that provides survival-predictive value.

Deconstructing fibrosis research: do pro-fibrotic signals point the way for chronic dermal wound regeneration?

Chronic wounds are characterized by inadequate matrix synthesis, no re-epithelialization, infection and ultimately no wound resolution. In contrast, fibrosis is characterized by overproduction of matrix and excess matrix contraction. As research in the fields of chronic wounds and fibrosis surges forward, important parallels can now be drawn between the dysfunctions in fibrotic diseases and the needs of chronic wounds. These parallels exist at both the macroscopic level and at the molecular level. Thus in finding the individual factors responsible for the progression of fibrotic diseases, we may identify new therapeutic targets for the resolution of chronic wounds. The aim of this review is to discuss how recent advances in fibrosis research have found a home in the treatment of chronic wounds and to highlight the benefits that can be obtained for chronic wound treatments by employing a translational approach to molecules identified in fibrosis research.

Epithelial-mesenchymal transition in pancreatic carcinoma

Pancreatic carcinoma is the fourth-leading cause of cancer death and is characterized by early invasion and metastasis. The developmental program of epithelial-mesenchymal transition (EMT) is of potential importance for this rapid tumor progression. During EMT, tumor cells lose their epithelial characteristics and gain properties of mesenchymal cells, such as enhanced motility and invasive features. This review will discuss recent findings pertinent to EMT in pancreatic carcinoma. Evidence for and molecular characteristics of EMT in pancreatic carcinoma will be outlined, as well as the connection of EMT to related topics, e.g., cancer stem cells and drug resistance.

Spatiotemporal localization of periostin and its potential role in epithelial-mesenchymal transition during palatal fusion

The medial epithelial seam (MES) between the palatal shelves degrades during palatal fusion to achieve the confluence of palatal mesenchyme. Cellular mechanisms underlying the degradation of MES have been proposed, such as apoptosis, epithelial-mesenchymal transition (EMT) and migration of medial edge epithelia (MEE). Extracellular matrix components have been shown to play an important role in EMT in many model systems. Periostin (also known as osteoblast-specific factor-2) is a secreted mesenchymal extracellular matrix component that affects the ability of cells to migrate and/or facilitates EMT during both embryonic development and pathologic conditions. In this study, we evaluated the spatiotemporal expression patterns of periostin during mouse palatal fusion by in situ hybridization and immunofluorescence. Periostin mRNA and protein were present in the palatal mesenchyme, the protein being distributed in a fine fibrillar network and in the basement membrane, but absent from the epithelium. During MES degradation, the protein was strongly expressed in the basement membrane underlying the MES and in some select MEE. Confocal microscopic analysis using an EMT marker, twist1, and an epithelial marker, cytokeratin 14, provided evidence that select MEE were undergoing EMT in association with periostin. Moreover, the major extracellular matrix molecules in basement membrane, laminin and collagen type IV were degraded earlier than periostin. The result is that select MEE establish interactions with periostin in the mesenchymal extracellular matrix, and these new cell-matrix interactions may regulate MEE transdifferentiation during palatal fusion.

Increased expression and serum levels of the stromal cell-secreted protein periostin in breast cancer bone metastases

Periostin, a matricellular protein, is overexpressed in the stroma of several cancers. The aim of our study was to investigate more specifically whether periostin expression is associated with bone metastases from breast cancer and to determine its source in the affected bone. Nude mice were inoculated with human MDA-B02 breast cancer cells. Bone metastases-bearing mice were treated with zoledronic acid-an antiresorptive drug-or vehicle. Bone metastases were examined for tumor- and stroma-derived periostin expression by quantitative polymerase chain reaction with human- and mouse-specific primers and immunohistochemistry. Serum periostin and conventional bone turnover markers were also measured. MDA-B02 cells did not express periostin both in vitro and in vivo. However, mouse-derived periostin was markedly overexpressed (eightfold) in metastatic legs compared to noninoculated mice. Serum periostin levels were also markedly increased in metastatic mice and correlated with in situ expression levels. Immunostaining showed that periostin derived from the environing stromal cells of bone metastasis. Bone turnover blockade by zoledronic acid markedly decreased osteolytic lesions but only slightly modulated serum periostin levels. Bone metastases from breast cancer induce overexpression of periostin by surrounding stromal cells. Periostin could be a biochemical marker of the early stromal response associated to breast cancer bone metastasis formation.

Development of a new ELISA for serum periostin: evaluation of growth-related changes and bisphosphonate treatment in mice

Periostin is a gamma-carboxyglutamic acid protein preferentially expressed in periosteum and bone mesenchymal stem cells. Lack of a precise assay for measuring circulating levels impairs the investigation of its biological significance. We developed a new ELISA and studied changes of periostin levels both locally at the bone site and systemically in circulating blood during growth and after bisphosphonate-induced inhibition of bone remodeling in the mouse. The ELISA we developed is based on an affinity-purified polyclonal antibody that was raised against the C-terminal sequence of mouse periostin. Reproducibility, repeatability, precision, and accuracy tests met standards of acceptance. Serum periostin and levels of the bone turnover markers osteocalcin, PINP, CTX-I, and TRAP5b were measured in (1) 4-, 6-, 8-, 10-, and 12-week-old wild-type female Balb/c mice and (2) adult ovariectomized female Balb/c mice treated with zoledronic acid or vehicle. Serum periostin decreased during growth and stabilized from 8 weeks and older, its levels correlating with bone turnover markers. Immunohistochemistry in bones from different growth stages showed that periostin localized specifically at the sites of endochondral and intramembranous ossification, especially at the periosteal envelopes. Zoledronic acid induced a marked decrease in bone remodeling markers but did not alter serum periostin levels or periostin immunostaining pattern. The novel ELISA is highly specific and allows accurate and precise measurements of serum periostin levels in mice.

Periostin promotes ovarian cancer angiogenesis and metastasis

OBJECTIVE

Perostin (PN) has been found to be overexpressed in a variety of human malignancies including ovarian cancer. In the present study, we investigated PN expression status in a large cohort of ovarian tumors with the focus on biological influence of PN related on ovarian tumor angiogenesis and metastasis.

METHODS

PN expression was determined by cDNA microarray, PN northern blot and PN IHC tissue array analyses. Exogenous PN expression in ovarian cancer cells OVCAR-3 and OV2008 were achieved through retroviral transfection and confirmed by PN western blot and ELISA. The effects of exogenous PN expression on tumor angiogenesis and metastatic growth were accessed in orthotopic mouse models. The in vitro cell adhesion, migration and invasion assays were performed to investigate the potential mechanisms involved in PN's in vivo effects.

RESULTS

PN was frequently overexpressed in ovarian tumors. Higher PN levels significantly correlated with clinical late stages (III/IV) and cancer recurrence. PN was produced by engineered PN-overexpressing cells at levels comparable to that of A2780 cells, an ovarian carcinoma cell line with endogenous PN expression. PN overexpression did not change cell growth rates in vitro; however it significantly promoted intraperitoneal tumor metastatic growth in immunodeficient mice, which was associated with increased tumor angiogenesis and decreased tumor cell apoptosis. In vitro purified PN promoted cell adhesion, migration, and invasion of both human umbilical endothelial cells (HUVECs) and/or ovarian cancer cells.

CONCLUSIONS

Our data indicate PN plays a critical role in both ovarian tumor angiogenesis and metastasis. Thus PN may represent a clinically effective new target for therapy of ovarian cancer.

Periostin is a collagen associated bone matrix protein regulated by parathyroid hormone

Periostin is a 90 kDa secreted protein, originally identified in murine osteoblast-like cells, with a distribution restricted to collagen-rich tissues and certain tumors. In this paper, we first analyzed the expression of periostin mRNA and protein in human fetal osteoblasts (hFOB) and human osteosarcoma (hOS) cell lines by RT real-time PCR and Western blot, respectively. The hFOB 1.19 and three hOS (MHM, KPDXM and Eggen) showed highly variable periostin mRNA levels and protein. Second, we showed that the expression of periostin mRNA was inversely related to the cells' abilities to differentiate and mineralize. Then, we investigated the regulation of periostin mRNA in hFOB after siRNA treatment and in mouse primary osteoblasts (mOB) treated with PTH. Knock-down of periostin mRNA, down-regulated PTHrP, but did not affect the expression of other important markers of differentiation such as RUNX2. In addition, periostin mRNA was transiently up-regulated in osteoblasts by PTH. Finally, the localization of periostin and its partially co-localization with collagen 1a1 mRNA and protein was studied in mouse embryos and postnatal pups using in situ hybridization and immunohistochemistry, respectively. In conclusion, the present study provides novel observations related to the expression, distribution and regulation of periostin in bone cells and extracellular matrix.

ARRDC3 suppresses breast cancer progression by negatively regulating integrin beta4

Large-scale genetic analyses of human tumor samples have been used to identify novel oncogenes, tumor suppressors and prognostic factors, but the functions and molecular interactions of many individual genes have not been determined. In this study we examined the cellular effects and molecular mechanism of the arrestin family member, ARRDC3, a gene preferentially lost in a subset of breast cancers. Oncomine data revealed that the expression of ARRDC3 decreases with tumor grade, metastases and recurrences. ARRDC3 overexpression represses cancer cell proliferation, migration, invasion, growth in soft agar and in vivo tumorigenicity, whereas downregulation of ARRCD3 has the opposite effects. Mechanistic studies showed that ARRDC3 functions in a novel regulatory pathway that controls the cell surface adhesion molecule, β-4 integrin (ITGβ4), a protein associated with aggressive tumor behavior. Our data indicates ARRDC3 directly binds to a phosphorylated form of ITGβ4 leading to its internalization, ubiquitination and ultimate degradation. The results identify the ARRCD3-ITGβ4 pathway as a new therapeutic target in breast cancer and show the importance of connecting genetic arrays with mechanistic studies in the search for new treatments.

Proteomic analysis of differentially expressed proteins in peripheral cholangiocarcinoma

Cholangiocarcinoma is an adenocarcinoma of the liver which has increased in incidence over the last thirty years to reach similar levels to other liver cancers. Diagnosis of this disease is usually late and prognosis is poor, therefore it is of great importance to identify novel candidate markers and potential early indicators of this disease as well as molecules that may be potential therapeutic targets. We have used a proteomic approach to identify differentially expressed proteins in peripheral cholangiocarcinoma cases and compared expression with paired non-tumoral liver tissue from the same patients. Two-dimensional fluorescence difference gel electrophoresis after labeling of the proteins with cyanines 3 and 5 was used to identify differentially expressed proteins. Overall, of the approximately 2,400 protein spots visualised in each gel, 172 protein spots showed significant differences in expression level between tumoral and non-tumoral tissue with p < 0.01. Of these, 100 spots corresponding to 138 different proteins were identified by mass spectrometry: 70 proteins were over-expressed whereas 68 proteins were under-expressed in tumoral samples compared to non-tumoral samples. Among the over-expressed proteins, immunohistochemistry studies confirmed an increased expression of 14-3-3 protein in tumoral cells while α-smooth muscle actin and periostin were shown to be overexpressed in the stromal myofibroblasts surrounding tumoral cells. α-Smooth muscle actin is a marker of myofibroblast differentiation and has been found to be a prognostic indicator in colon cancer while periostin may also have a role in cell adhesion, proliferation and migration and has been identified in other cancers. This underlines the role of stromal components in cancer progression and their interest for developing new diagnostic or therapeutic tools.

Periostin is up-regulated in high grade and high stage prostate cancer

BACKGROUND

Expression of periostin is an indicator of epithelial-mesenchymal transition in cancer but a detailed analysis of periostin expression in prostate cancer has not been conducted so far.

METHODS

Here, we evaluated periostin expression in prostate cancer cells and peritumoural stroma immunohistochemically in two independent prostate cancer cohorts, including a training cohort (n = 93) and a test cohort (n = 325). Metastatic prostate cancers (n = 20), hormone refractory prostate cancers (n = 19) and benign prostatic tissues (n = 38) were also analyzed.

RESULTS

In total, strong epithelial periostin expression was detectable in 142 of 418 (34.0%) of prostate carcinomas and in 11 of 38 benign prostate glands (28.9%). Increased periostin expression in carcinoma cells was significantly associated with high Gleason score (p < 0.01) and advanced tumour stage (p < 0.05) in the test cohort. Whereas periostin expression was weak or absent in the stroma around normal prostate glands, strong periostin expression in tumour stroma was found in most primary and metastatic prostate cancers. High stromal periostin expression was associated with higher Gleason scores (p < 0.001). There was a relationship between stromal periostin expression and shortened PSA relapse free survival times in the training cohort (p < 0.05).

CONCLUSIONS

Our data indicate that periostin up-regulation is related to increased tumour aggressiveness in prostate cancer and might be a promising target for therapeutical interventions in primary and metastatic prostate cancer.

Periostin, a cell adhesion molecule, facilitates invasion in the tumor microenvironment and annotates a novel tumor-invasive signature in esophageal cancer

Human squamous cell cancers are the most common epithelially derived malignancies. One example is esophageal squamous cell carcinoma (ESCC), which is associated with a high mortality rate that is related to a propensity for invasion and metastasis. Here, we report that periostin, a highly expressed cell adhesion molecule, is a key component of a novel tumor-invasive signature obtained from an organotypic culture model of engineered ESCC. This tumor-invasive signature classifies with human ESCC microarrays, underscoring its utility in human cancer. Genetic modulation of periostin promotes tumor cell migration and invasion as revealed in gain-of-loss and loss-of-function experiments. Inhibition of epidermal growth factor receptor signaling and restoration of wild-type p53 function were each found to attenuate periostin, suggesting the interdependence of two common genetic alterations with periostin function. Collectively, our studies reveal periostin as an important mediator of ESCC tumor invasion and they indicate that organotypic (three-dimensional) culture can offer an important tool to discover novel biological effectors in cancer.

Role of matricellular proteins in cardiac tissue remodeling after myocardial infarction

After onset of myocardial infarction (MI), the left ventricle (LV) undergoes a continuum of molecular, cellular, and extracellular responses that result in LV wall thinning, dilatation, and dysfunction. These dynamic changes in LV shape, size, and function are termed cardiac remodeling. If the cardiac healing after MI does not proceed properly, it could lead to cardiac rupture or maladaptive cardiac remodeling, such as further LV dilatation and dysfunction, and ultimately death. Although the precise molecular mechanisms in this cardiac healing process have not been fully elucidated, this process is strictly coordinated by the interaction of cells with their surrounding extracellular matrix (ECM) proteins. The components of ECM include basic structural proteins such as collagen, elastin and specialized proteins such as fibronectin, proteoglycans and matricellular proteins. Matricellular proteins are a class of non-structural and secreted proteins that probably exert regulatory functions through direct binding to cell surface receptors, other matrix proteins, and soluble extracellular factors such as growth factors and cytokines. This small group of proteins, which includes osteopontin, thrombospondin-1/2, tenascin, periostin, and secreted protein, acidic and rich in cysteine, shows a low level of expression in normal adult tissue, but is markedly upregulated during wound healing and tissue remodeling, including MI. In this review, we focus on the regulatory functions of matricellular proteins during cardiac tissue healing and remodeling after MI.

Molecular mechanism of pancreatic cancer--understanding proliferation, invasion, and metastasis

INTRODUCTION

The purpose of this review is to highlight the molecular mechanisms leading to the development and progression of pancreatic ductal adenocarcinoma (PDAC) with particular emphasis on tumor cell proliferation, local invasion, and metastasis. Recent advances in the field of PDAC biology have shed light on the molecular events that trigger PDAC initiation and maintenance.

RESULTS

It is now clear that apart from the genetic alterations within the tumor cells, interactions of the tumor with its environment are necessary for proliferation and invasion. Interestingly, a number of developmental signaling pathways are reactivated in PDAC. Progress has also been made in the understanding of the molecular events that govern the process of metastasis.

CONCLUSION

Although our understanding of the mechanisms underlying PDAC pathobiology are more advanced than ever, little progress has been made in the clinical treatment of PDAC, and successful bench-to-bedside transfer of knowledge to boost new treatment options is still unsatisfying.

Overexpression of periostin and lumican in esophageal squamous cell carcinoma

To identify biomarkers for early detection for esophageal squamous cell carcinoma (ESCC), we previously carried out a genome-wide gene expression profiling study using an oligonucleotide microarray platform. This analysis led to identification of several transcripts that were significantly upregulated in ESCC compared to the adjacent normal epithelium. In the current study, we performed immunohistochemical analyses of protein products for two candidates genes identified from the DNA microarray analysis, periostin (POSTN) and lumican (LUM), using tissue microarrays. Increased expression of both periostin and lumican was observed in 100% of 137 different ESCC samples arrayed on tissue microarrays. Increased expression of periostin and lumican was observed in carcinoma as well as in stromal cell in the large majority of cases. These findings suggest that these candidates can be investigated in the sera of ESCC patients using ELISA or multiple reaction monitoring (MRM) type assays to further explore their utility as biomarkers.