Periostin induction in tumor cell line explants and inhibition of in vitro cell growth by anti-periostin antibodies

Periostin's role in uterine leiomyoma development: a mini-review on the potential periostin poses as a pharmacological intervention for uterine leiomyoma

Uterine leiomyomas, also known as fibroids or myomas, occur in an estimated 70-80% of reproductive aged women. Many experience debilitating symptoms including pelvic pain, abnormal uterine bleeding (AUB), dyspareunia, dysmenorrhea, and infertility. Current treatment options are limited in preserving fertility, with many opting for sterilizing hysterectomy as a form of treatment. Currently, surgical interventions include hysterectomy, myomectomy, and uterine artery embolization in addition to endometrial ablation to control AUB. Non-surgical hormonal interventions, including GnRH agonists, are connotated with negative side effects and are unacceptable for women desiring fertility. Periostin, a regulatory extra cellular matrix (ECM) protein, has been found to be expressed in various gynecological diseases including leiomyomas. We previously determined that periostin over-expression in immortalized myometrial cells led to the development of a leiomyoma-like cellular phenotype. Periostin is induced by TGF-β, signals through the PI3K/AKT pathway, induces collagen production, and mediates wound repair and fibrosis, all of which are implicated in leiomyoma pathology. Periostin has been linked to other gynecological diseases including ovarian cancer and endometriosis and is being investigated as pharmacological target for treating ovarian cancer, post-surgical scarring, and numerous other fibrotic conditions. In this review, we provide discussion linking pathological inflammation and wound repair, with a TGF-β-periostin-collagen signaling in the pathogenesis of leiomyomas, and ultimately the potential of periostin as a druggable target to treat leiomyomas.

Heart Failure Promotes Cancer Progression in an Integrin β1-Dependent Manner

Heart failure and cancer are currently the deadliest diseases in the Western world, posing the most pressing clinical challenges that remain unmet today. Both conditions share similar risk factors, including age, genetics, lifestyle, chronic inflammation, stress, and more. Furthermore, medications that are being used to counteract cancer frequently result in cardiotoxicity and the spontaneous emergence of heart failure. Thus, heart failure and cancer display an intimate connection and share similarities. Recent studies show that cardiac remodeling and heart failure promote cancer progression and metastasis. Using three different mouse models for heart failure revealed that the communication between the remodeled heart and the tumor is facilitated through multiple secreted factors. Among these factors, Periostin was consistently found to be elevated in all models and was shown to be required in vitro. Yet, whether Periostin is necessary for tumor promotion in vivo is unknown. Towards this end, we examined tumor promotion in mice lacking Periostin following transverse aortic constriction (TAC). Despite the loss of Periostin, tumor growth was promoted in the TAC-operated mice. This likely occurred due to increased levels of various cytokines and growth factors in Periostin KO mice. Many of these factors are potential ligands of Integrin receptors. Therefore, we next studied the role of Integrin receptors in the tumor-promotion phenotype following heart failure. We generated cancer cells with an Integrin β1 loss of function mutation and examined tumor growth in the presence and absence of heart failure. Integrin β1 KO cancer cells fail to display cardiac-remodeling-dependent tumor-promotion. Interestingly, a previous study showed that renal cell carcinoma cells (Renca) fail to be promoted following a myocardial infarction. Consistently, we show that Renca cells do not respond to secreted factors derived from the failing heart both in vitro and in vivo. Interestingly, Renca cells display low basal mRNA levels of Integrin β1 which may explain the inability of heart failure to promote their growth. The findings may have significant clinical relevance to cardio-oncology patients who suffer from cancers with high levels of Integrin β1. Chemotherapy leading to cardiotoxicity in these patients may generate a vicious cycle with poor prognosis.

Cleavage of periostin by MMP9 protects mice from kidney cystic disease

The matrix metalloproteinase MMP9 influences cellular morphology and function, and plays important roles in organogenesis and disease. It exerts both protective and deleterious effects in renal pathology, depending upon its specific substrates. To explore new functions for MMP9 in kidney cysts formation and disease progression, we generated a mouse model by breeding juvenile cystic kidney (jck) mice with MMP9 deficient mice. Specifically, we provide evidence that MMP9 is overexpressed in cystic tissue where its enzymatic activity is increased 7-fold. MMP9 deficiency in cystic kidney worsen cystic kidney diseases by decreasing renal function, favoring cyst expansion and fibrosis. In addition, we find that periostin is a new critical substrate for MMP9 and in its absence periostin accumulates in cystic lining cells. As periostin promotes renal cyst growth and interstitial fibrosis in polycystic kidney diseases, we propose that the control of periostin by MMP9 and its associated intracellular signaling pathways including integrins, integrin-linked kinase and focal adhesion kinase confers to MMP9 a protective effect on the severity of the disease.

The Effects of Periostin Expression on Fibroid-Like Transition of Myometrial Cells

Fibroids, benign tumors of the myometrium, are the most common tumors in women and are associated with spontaneous abortion, preterm birth, placenta abruption, and infertility, among others. The incidence of fibroids in reproductive aged women is 20-89%. Fibroids are characterized by high production of extracellular matrix (ECM), particularly collagens, which play a role in their growth. However, their pathogenesis is poorly understood. Recently, we and others have found periostin (POSTN), a regulatory ECM protein, to be overexpressed in the majority of fibroids analyzed. Periostin is an ECM protein that is a critical regulator and well-established biomarker for fibrosis in tissues such as the lung, skin, and kidney. Our hypothesis was that periostin plays a role in the fibrotic transition of myometrial cells to fibroid cells. To test this, we evaluated the effects of POSTN overexpression in myometrial cells. Telomerase-immortalized myometrial cells were transduced with control or POSTN-overexpression lentivirus particles, generating one control (dCas9-Mock) and two overexpression (dCas9-POSTN-01, dCas9-POSTN-02) cell lines. Overexpression of POSTN in immortalized myometrial cells resulted in a change in phenotype consistent with fibroid cells. They upregulated expression of key fibroid genes and had increased proliferation, adhesion, and migration in vitro. Here, we show a potential role for periostin in the transition of myometrial cells to fibroid cells, giving rationale for future investigation into the role of periostin in fibroid pathogenesis and its potential as a therapeutic target.

Periostin: biology and function in cancer

Periostin (POSTN), a member of the matricellular protein family, is a secreted adhesion-related protein produced in the periosteum and periodontal ligaments. Matricellular proteins are a nonstructural family of extracellular matrix (ECM) proteins that regulate a wide range of biological processes in both normal and pathological conditions. Recent studies have demonstrated the key roles of these ECM proteins in the tumor microenvironment. Furthermore, periostin is an essential regulator of bone and tooth formation and maintenance, as well as cardiac development. Also, periostin interacts with multiple cell-surface receptors, especially integrins, and triggers signals that promote tumor growth. According to recent studies, these signals are implicated in cancer cell survival, epithelial-mesenchymal transition (EMT), invasion, and metastasis. In this review, we will summarize the most current data regarding periostin, its structure and isoforms, expressions, functions, and regulation in normal and cancerous tissues. Emphasis is placed on its association with cancer progression, and also future potential for periostin-targeted therapeutic approaches will be explored.

The Role of Periostin in Angiogenesis and Lymphangiogenesis in Tumors

Simple Summary

Cancers are common diseases that affect people of all ages worldwide. For this reason, continuous attempts are being made to improve current therapeutic options. The formation of metastases significantly decreases patient survival. Therefore, understanding the mechanisms that are involved in this process seems to be crucial for effective cancer therapy. Cancer dissemination occurs mainly through blood and lymphatic vessels. As a result, many scientists have conducted a number of studies on the formation of new vessels. Many studies have shown that proangiogenic factors and the extracellular matrix protein, i.e., periostin, may be important in tumor angio- and lymphangiogenesis, thus contributing to metastasis formation and worsening of the prognosis.

Abstract

Periostin (POSTN) is a protein that is part of the extracellular matrix (ECM) and which significantly affects the control of intracellular signaling pathways (PI3K-AKT, FAK) through binding integrin receptors (αvβ3, αvβ5, α6β4). In addition, increased POSTN expression enhances the expression of VEGF family growth factors and promotes Erk phosphorylation. As a result, this glycoprotein controls the Erk/VEGF pathway. Therefore, it plays a crucial role in the formation of new blood and lymphatic vessels, which may be significant in the process of metastasis. Moreover, POSTN is involved in the proliferation, progression, migration and epithelial-mesenchymal transition (EMT) of tumor cells. Its increased expression has been detected in many cancers, including breast cancer, ovarian cancer, non-small cell lung carcinoma and glioblastoma. Many studies have shown that this protein may be an independent prognostic and predictive factor in many cancers, which may influence the choice of optimal therapy.

Impact of Secretion-Active Osteoblast-Specific Factor 2 in Promoting Progression and Metastasis of Head and Neck Cancer

Treatment success of head and neck cancer (HNC) is still hampered by tumor relapse due to metastases. Our study aimed to identify biomarkers by exploiting transcriptomics profiles of patient-matched metastases, primary tumors, and normal tissue mucosa as well as the TCGA HNC cohort data sets. Analyses identified osteoblast-specific factor 2 (OSF-2) as significantly overexpressed in lymph node metastases and primary tumors compared to normal tissue. High OSF-2 levels correlate with metastatic disease and reduced overall survival of predominantly HPV-negative HNC patients. No significant correlation was observed with tumor localization or therapy response. These findings were supported by the fact that OSF-2 expression was not elevated in cisplatin-resistant HNC cell lines. OSF-2 was strongly expressed in tumor-associated fibroblasts, suggesting a tumor microenvironment-promoting function. Molecular cloning and expression studies of OSF-2 variants from patients identified an evolutionary conserved bona fide protein secretion signal (1MIPFLPMFSLLLLLIVNPINA21). OSF-2 enhanced cell migration and cellular survival under stress conditions, which could be mimicked by the extracellular administration of recombinant protein. Here, OSF-2 executes its functions via ß1 integrin, resulting in the phosphorylation of PI3K and activation of the Akt/PKB signaling pathway. Collectively, we suggest OSF-2 as a potential prognostic biomarker and drug target, promoting metastases by supporting the tumor microenvironment and lymph node metastases survival rather than by enhancing primary tumor proliferation or therapy resistance.

Periostin as a key molecule defining desmoplastic environment in colorectal cancer

Categorizing desmoplastic reaction (DR) based on the histological findings of cancer-associated fibroblasts is shown to be a promising novel method to predict prognosis of patients with colorectal cancer (CRC). Periostin (POSTN) in cancer-associated stroma is reportedly associated with poor clinical outcomes. Immunohistochemical staining with an anti-POSTN antibody was performed in 73 patients with pStage III CRC (cohort 1). In addition, to evaluate mRNA and protein expression levels of POSTN, we analyzed paired normal and invasive cancer frozen specimens by quantitative real-time polymerase chain reaction and western blot analysis in 41 patients (cohort 2). In cohort 1, according to the DR categorization, 18, 22, and 33 patients were classified as immature, intermediate, and mature, respectively. High immunoreactivity of POSTN was observed 100%, 68.2%, and 27.3%, respectively (p < 0.0001). The 5-year relapse-free survival rates were 56.8% and 82.7% in high and low POSTN expression subgroups, respectively (p = 0.015). In cohort 2, the POSTN mRNA and protein levels were significantly higher in the immature stroma as compared to the stroma characterized as other DR patterns. POSTN expression was closely associated with DR categorization. POSTN may be a key molecule that contributes to the malignant potential of CRC.

Early Cardiac Remodeling Promotes Tumor Growth and Metastasis

BACKGROUND

Recent evidence suggests that cancer and cardiovascular diseases are associated. Chemotherapy drugs are known to result in cardiotoxicity, and studies have shown that heart failure and stress correlate with poor cancer prognosis. However, whether cardiac remodeling in the absence of heart failure is sufficient to promote cancer is unknown.

METHODS

To investigate the effect of early cardiac remodeling on tumor growth and metastasis colonization, we used transverse aortic constriction (TAC), a model for pressure overload-induced cardiac hypertrophy, and followed it by cancer cell implantation.

RESULTS

TAC-operated mice developed larger primary tumors with a higher proliferation rate and displayed more metastatic lesions compared with controls. Serum derived from TAC-operated mice potentiated cancer cell proliferation in vitro, suggesting the existence of secreted tumor-promoting factors. Using RNA-sequencing data, we identified elevated mRNA levels of periostin in the hearts of TAC-operated mice. Periostin levels were also found to be high in the serum after TAC. Depletion of periostin from the serum abrogated the proliferation of cancer cells; conversely, the addition of periostin enhanced cancer cell proliferation in vitro. This is the first study to show that early cardiac remodeling nurtures tumor growth and metastasis and therefore promotes cancer progression.

CONCLUSIONS

Our study highlights the importance of early diagnosis and treatment of cardiac remodeling because it may attenuate cancer progression and improve cancer outcome.

Periostin plays a critical role in the cell cycle in lung fibroblasts

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a devastating disease with a median survival of only three to 5 years. Fibroblast proliferation is a hallmark of IPF as is secretion of extracellular matrix proteins from fibroblasts. However, it is still uncertain how IPF fibroblasts acquire the ability to progressively proliferate. Periostin is a matricellular protein highly expressed in the lung tissues of IPF patients, playing a critical role in the pathogenesis of pulmonary fibrosis. However, it remains undetermined whether periostin affects lung fibroblast proliferation.

METHODS

In this study, we first aimed at identifying periostin-dependently expressed genes in lung fibroblasts using DNA microarrays. We then examined whether expression of cyclins and CDKs controlling cell cycle progression occur in a periostin-dependent manner. We next examined whether downregulation of cell proliferation-promoting genes by knockdown of periostin or integrin, a periostin receptor, using siRNA, is reflected in the cell proliferation of lung fibroblasts. We then looked at whether lung fibroblasts derived from IPF patients also require periostin for maximum proliferation. We finally investigated whether CP4715, a potent inhibitor against integrin α_Vβ₃ (a periostin receptor), which we have recently found blocks TGF-β signaling, followed by reduced BLM-induced pulmonary fibrosis in mice, can block proliferation of lung fibroblasts derived from IPF patients.

RESULTS

Many cell-cycle-related genes are involved in the upregulated or downregulated genes by periostin knockdown. We confirmed that in lung fibroblasts, periostin silencing downregulates expression of several cell-cycle-related molecules, including the cyclin, CDK, and, E2F families, as well as transcription factors such as B-MYB and FOXM1. Periostin or integrin silencing slowed proliferation of lung fibroblasts and periostin silencing increased the distribution of the G0/G1 phase, whereas the distribution of the G2/M phase was decreased. Lung fibroblasts derived from IPF patients also required periostin for maximum proliferation. Moreover, CP4715 downregulated proliferation along with expression of cell-cycle-related genes in IPF lung fibroblasts as well as in normal lung fibroblasts.

CONCLUSIONS

Periostin plays a critical role in the proliferation of lung fibroblasts and the present results provide us a solid basis for considering inhibitors of the periostin/integrin α_Vβ₃ interaction for the treatment of IPF patients.

Tumor Immune Microenvironment and Chemosensitivity Signature for Predicting Response to Chemotherapy in Gastric Cancer

Current gastric cancer staging alone cannot predict prognosis and adjuvant chemotherapy benefits in stage II and III gastric cancer. Tumor immune microenvironment biomarkers and tumor-cell chemosensitivity might add predictive value to staging. This study aimed to construct a predictive signature integrating tumor immune microenvironment and chemosensitivity-related features to improve the prediction of survival and adjuvant chemotherapy benefits in patients with stage II to III gastric cancer. We used IHC to assess 26 features related to tumor, stroma, and chemosensitivity in tumors from 223 patients and evaluated the association of the features with disease-free survival (DFS) and overall survival (OS). Support vector machine (SVM)-based methods were used to develop the predictive signature, which we call the SVM signature. Validation of the signature was performed in two independent cohorts of 445 patients. The diagnostic signature integrated seven features: CD3⁺ cells at the invasive margin (CD3 IM), CD8⁺ cells at the IM (CD8 IM), CD45RO⁺ cells in the center of tumors (CD45RO CT), CD66b⁺ cells at the IM (CD66b IM), CD34⁺ cells, periostin, and cyclooxygenase-2. Patients fell into low- and high-SVM groups with significant differences in 5-year DFS and OS in the training and validation cohorts (all P < 0.001). The signature was an independent prognosis indicator in multivariate analysis in each cohort. The signature had better prognostic value than various clinicopathologic risk factors and single features. High-SVM patients exhibited a favorable response to adjuvant chemotherapy. Thus, this SVM signature predicted survival and has the potential for identifying patients with stage II and III gastric cancer who could benefit from adjuvant chemotherapy.

Periostin Mediates Right Ventricular Failure through Induction of Inducible Nitric Oxide Synthase Expression in Right Ventricular Fibroblasts from Monocrotaline-Induced Pulmonary Arterial Hypertensive Rats

Pulmonary arterial hypertension (PAH) leads to lethal right ventricular failure (RVF). Periostin (POSTN) mRNA expression is increased in right ventricles (RVs) of monocrotaline (MCT)-induced PAH model rats. However, the pathophysiological role of POSTN in RVF has not been clarified. We investigated the effects of POSTN on inducible nitric oxide (NO) synthase (iNOS) expression and NO production, which causes cardiac dysfunction, in right ventricular fibroblasts (RVFbs). Male Wistar rats were intraperitoneally injected with MCT (60 mg/kg) or saline. Three weeks after injection, RVFbs were isolated from RVs of MCT- or saline-injected rats (MCT-RVFb or CONT-RVFb). In MCT-RVFb, iNOS expression and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and nuclear factor-kappa B (NF-κB) were higher than those in CONT-RVFb. Recombinant POSTN increased iNOS expression and NO production, which were prevented by a pharmacological inhibition of ERK1/2, JNK or NF-κB in RVFbs isolated from normal rats. Culture medium of POSTN-stimulated RVFbs suppressed Ca²⁺ inflow through l-type Ca²⁺ channel (LTCC) in H9c2 cardiomyoblasts. We demonstrated that POSTN enhances iNOS expression and subsequent NO production via ERK1/2, JNK, and NF-κB signaling pathways in RVFbs. POSTN might mediate RVF through the suppression of LTCC activity of cardiomyocytes by producing NO from RVFbs in PAH model rats.

Tumor suppression effect of targeting periostin with siRNA in a nude mouse model of human laryngeal squamous cell carcinoma

BACKGROUND

The incidence of laryngeal carcinoma is increasing, however, the mechanism is not fully understood. We aimed to investigate the efficacy of periostin gene silencing by siRNA on tumor inhibition, in a novel nude mouse model of human laryngeal squamous cell carcinoma, and to explore possible inhibitory mechanisms.

METHODS

Tumors were established in nude mice by transplantation of LSCC AMC-HN-8 cell line. Forty-eight nude mice were randomly divided into groups of eight each, and treated with high (1.0 OD) or low (0.5 OD) doses of periostin-siRNA or appropriate control solutions. Tumor growth was observed and used to calculate an inhibition rate (%). Routine pathological and electron microscopic examination were used to determine tumor apoptosis and proliferation. Changes in periostin mRNA and protein levels were analyzed.

RESULTS

Tumor growth was significantly inhibited in mice treated by high dose periostin-siRNA compared to untreated and those treated with low dose periostin-siRNA (P < 0.05). Pathological examination showed increased tumor necrosis and apoptotic changes in treated mice, which was confirmed by electron microscopy. Periostin mRNA and protein expression were significantly reduced in tumors from mice treated with high dose periostin-siRNA, compared to controls and low-dose periostin-siRNA treatment groups (P < 0.05).

CONCLUSION

Periostin silencing was associated with growth inhibition of tumor cells in a nude mouse model of LSCC. The underlying mechanism may be due to receptor-mediated induction of relevant signal transduction pathways that modulate the microenvironment needed for cancer cell survival. Periostin is expected to become a new target for cancer therapy.

The Role of Periostin in Capsule Formation on Silicone Implants

Although silicone implants are widely used in breast and other reconstructive surgeries, the limited biocompatibility of these materials leads to severe complications, including capsular contracture. Here, we aimed to clarify the relationship between periostin and the process of capsule formation after in vivo implantation. Seven-week-old wild-type (WT) C57BL/6 mice and periostin-deficient mice were used. Round silicone implants were inserted into a subcutaneous pocket on the dorsum of the mice. After 8 weeks, the fibrous capsule around the implant was harvested and histologically examined to estimate capsular thickness and the number of inflammatory cells. Additionally, immunohistochemical analysis (periostin, α-SMA, and collagen type I) and western blotting (CTGF, TGF-β, VEGF, and MPO) were performed for a more detailed analysis of capsule formation. The capsules in periostin-knockout mice (PN-KO) were significantly thinner than those in WT mice. PN-KO mice showed significantly lower numbers of inflammatory cells than WT mice. Fibrous tissue formation markers (α-SMA, periostin, collagen type I, and CTGF) were significantly reduced in PN-KO mice. We also confirmed that inflammatory reaction and angiogenesis indicators (TGF-β, MPO, and VEGF) had lower expression in PN-KO mice. Inhibition of periostin could be important for suppressing capsule formation on silicone implants after in vivo implantation.

1H, 13C, and 15N resonance assignments of FAS1-IV domain of human periostin, a component of extracellular matrix proteins

Periostin, an extracellular matrix protein, is secreted by fibroblasts and is overexpressed in various types of cancers. The four internal repeat fasciclin 1 (FAS1) domains of human periostin play crucial roles in promoting tumor metastasis and progression via interaction with cell surface integrins. Among four FAS1 domains of human periostin, the fourth FAS1 domain (FAS1-IV) was prepared for NMR study, since only FAS1-IV was highly soluble, and showed a well-dispersed 2D ¹H-¹⁵N HSQC spectrum. Here, we report nearly complete backbone and side chain resonance assignments and a secondary structural analysis of the FAS1-IV domain as first steps toward the structure determination of FAS1-IV of human periostin.

Heterogeneous Periostin Expression in Different Histological Variants of Papillary Thyroid Carcinoma

Background

Periostin (PN) epithelial and stromal overexpression in tumor pathology has been studied according to tumor growth, angiogenesis, invasiveness, and metastasis, but a limited number of studies address PN in thyroid tumors.

Aim

Our study aimed to analyze PN expression in different histological variants of PTC and to correlate its expression with the clinicopathological prognostic factors.

Material and Methods

PN expression has been immunohistochemically assessed in 50 cases of PTC (conventional, follicular, oncocytic, macrofollicular, and tall cell variants), in tumor epithelial cells and intratumoral stroma. The association between PN expression and clinicopathological characteristics has been evaluated.

Results

Our results show that PTC presented different patterns of PN immunoreaction, stromal PN being significantly associated with advanced tumor stage and extrathyroidal extension. No correlations were found between PN overexpression in tumor epithelial cells and clinicopathological features, except for specific histological variants, the highest risk of poor outcome being registered for the conventional subtype in comparison to the oncocytic type.

Conclusions

Our study demonstrates differences in PN expression in histological subtypes of PTC. Our results plead in favor of a dominant protumorigenic role of stromal PN, while the action of epithelial PN is less noticeable.

Periostin has a protective role in melatonin‑induced cell apoptosis by inhibiting the eIF2α‑ATF4 pathway in human osteoblasts

The present study aimed to investigate the role of periostin (POSTN) and high melatonin concentrations in the apoptosis of hFOB 1.19 human normal fetal osteoblastic cells. hFOB 1.19 human osteoblastic cells were stably cultured and treated in different concentrations of melatonin for different durations of action. Apoptosis was assessed quantitatively using flow cytometric analysis. The results of western blot analysis demonstrated that the treatment of cells with different concentrations of melatonin for different durations of action revealed a positive association between melatonin and the expression levels of glucose‑regulated protein (GRP)78, GRP94, phosphorylated (p‑) eukaryotic initiation factor 2α (eIF2α), activating transcription factor (ATF)4, CCAAT/enhanced binding protein homologous protein (CHOP), cleaved caspase‑3, p‑c‑Jun N‑terminal kinase (JNK) and POSTN. When POSTN was inhibited, the levels of p‑JNK, CHOP, p‑eIF2α, ATF4 and cleaved caspase‑3 were significantly increased, whereas other proteins associated with the endoplasmic reticulum stress (ERS) pathways, including ATF6 and X‑box binding protein 1 (XBP1), were not significantly altered. Reverse transcription‑quantitative polymerase chain reaction analysis was also performed to assess the relative mRNA levels of ATF4, ATF6 and XBP1. The results of the present study are the first, to the best of our knowledge, to demonstrate that melatonin induced apoptosis in hFOB 1.19 human osteoblastic cells by activating the ERS‑associated eIF2α‑ATF4 pathway and subsequently triggered the cascade effects of CHOP, caspase‑3 and JNK. POSTN may function as a protective factor for osteoblasts during this process by inhibiting the eIF2α‑ATF4 pathway.

Role and underlying mechanisms of the interstitial protein periostin in the diagnosis and treatment of malignant tumors

Invasion and metastasis are the major characteristics of malignant tumors and are complex processes involving multiple genes. Gene regulation is a precise, large and complex biological control system, and its underlying mechanisms remain to be elucidated. Mesenchymal-specific genes are expressed primarily by mesenchymal cells, and the expression products of these genes are molecules with various structures and functions, including secreted proteins and extracellular matrix proteins. The periostin gene has been newly identified as a mesenchymal-specific gene and an extracellular-matrix secreted protein. Periostin is able to bind to various subtypes of integrin receptors on the surface of the cell membrane. This triggers relevant signal transduction pathways to alter the microenvironment of cancer cells in order to facilitate their survival, invasion, metastasis and angiogenesis as well as enhance the tolerance to hypoxia and chemicals. Therefore, periostin is associated with the grade of malignancy, level of invasion and prognosis of malignant tumors. The in-depth study of periostin may provide an effective marker for tumor diagnosis and prognosis, as well as a novel treatment target.

Periostin promotes epithelial-mesenchymal transition via the MAPK/miR-381 axis in lung cancer

Periostin (POSTN, PN, or osteoblast-specific factor OSF-2) is a multifunctional cytokine that signals between the cell and the extracellular matrix. Periostin plays an important role in tumor development and is involved in carcinoma cell epithelial-mesenchymal transition (EMT), whereby mature epithelial cells undergo phenotypic morphological changes and become invasive, motile cells. Here, we discuss the molecular mechanisms involved in periostin-induced promotion of EMT in lung cancer cells. Online TCGA datasets demonstrate the prognostic relevance of periostin in lung cancer; a higher periostin level correlates with poor overall survival. Similarly, our IHC results show that high periostin expression is positively correlated with the EMT markers Snail and Twist, as well as stage of lung cancer. We found that recombinant periostin induces the EMT phenotype in lung cancer cells through the p38/ERK pathway, while pretreatment with chemical inhibitors prevented periostin-induced EMT induction. Moreover, we found that periostin regulates EMT by repressing microRNA-381 (miR-381) expression, which targets both Snail and Twist. Using the miR-381 mimic, we dramatically reversed periostin-induced Snail and Twist expression. Furthermore, periostin knockdown dramatically affected EMT markers and cell migration potential. The role of periostin in lung cancer progression is elucidated by the in vivo mouse model. Our findings indicate that changes in periostin expression in lung cancer may serve as a therapeutic target for the treatment of lung cancer metastasis.

Periostin expression in cancer-associated fibroblasts of invasive ductal breast carcinoma

Periostin (POSTN) is a secreted cell adhesion glycoprotein that plays an important role in proliferation, adhesion and migration processes, as well as in regulation of mechanisms related to epithelial-mesenchymal transition (EMT). It also plays a key role in angio- and lymphangiogenesis and in formation of distant metastases. The aim of this work was to determine expression of POSTN in invasive ductal breast carcinoma (IDC) and in non-invasive ductal carcinoma in situ (DCIS) and to correlate its expression with clinicopathological parameters. Material for immunohistochemical studies (IHC) comprise of 70 IDC cases, 44 DCIS cases and 21 cases of fibrocystic change (FC). Frozen (-80˚C) fragments of tumours taken from 41 patients with IDC were used for molecular studies (real-time PCR), including 11 cases of IDC subjected to laser capture microdissection (LCM). POSTN expression was shown mainly in tumour stromal cells, i.e. cancer-associated fibroblasts (CAFs). Statistically significant higher level of POSTN expression in CAFs in IDC as compared to FC (p<0.0001) was observed. Additionally, statistically elevated expression level of POSTN in CAFs in IDC relative to DCIS (p<0.0001) and significantly increased expression of POSTN in CAFs in DCIS in comparison to FC (p=0.0158) was also shown. High level of POSTN expression in CAFs in IDC (>8 IRS points) was significantly correlated with tumour malignancy grade (G) (p=0.0070). Moreover, higher POSTN expression by CAFs was associated with patient shorter overall survival. Significant increase of POSTN expression on mRNA and protein level in CAFs in IDC with the growing malignancy grade of the tumours (G) was shown. Furthermore, with the use of LCM method, statistically significant higher expression of mRNA POSTN in stromal cells relative to cancer cells (p<0.001) was noted. POSTN might be a factor playing an important role in the mechanism of IDC progression.

Role of periostin in esophageal, gastric and colon cancer

Periostin, also known as osteoblast-specific factor 2, is a cell-adhesion protein with pleiotropic properties. The protein serves a vital role in the maintenance and development of tooth and bone tissue, in addition to cardiac development and healing. Periostin levels are increased in several forms of cancer, including pancreatic, ovarian, colon, lung, breast, gastric, thyroid, and esophageal head and neck carcinomas. The present review highlights the key role of periostin in tumorigenesis, particularly in increasing cell survival, invasion, angiogenesis, epithelial-mesenchymal transition and metastasis of carcinoma cells by interacting with numerous cell-surface receptors, including integrins, in the phosphoinositide 3-kinase-Akt pathway. In addition, periostin actively affects the canonical Wnt signaling pathway of colorectal tumorigenesis. The current review focused on the involvement of periostin in the development of colorectal, esophageal and gastric cancer.

Translational aspects in targeting the stromal tumour microenvironment: from bench to bedside

Solid tumours comprise, not only malignant cells but also a variety of stromal cells and extracellular matrix proteins. These components interact via an array of signalling pathways to create an adaptable network that may act to promote or suppress cancer progression. To date, the majority of anti-tumour chemotherapeutic agents have principally sought to target the cancer cell. Consequently, resistance develops because of clonal evolution, as a result of selection pressure during tumour expansion. The concept of activating or inhibiting other cell types within the tumour microenvironment is relatively novel and has the advantage of targeting cells which are genetically stable and less likely to develop resistance. This review outlines key players in the stromal tumour microenvironment and discusses potential targeting strategies that may offer therapeutic benefit.

Novel highly specific anti-periostin antibodies uncover the functional importance of the fascilin 1-1 domain and highlight preferential expression of periostin in aggressive breast cancer

Periostin (POSTN), a secreted homodimeric protein that binds integrins αvβ3, αvβ5, and α6β4, was originally found to be expressed in fetal tissues and in the adult upon injury particularly bone fractures due to its role in remodelling and repair. Recently it was found to be over-expressed in human breast cancer and a variety of other tumour types including head and neck squamous cell carcinoma, where its overexpression correlates with increased tumour invasion. Progress in studying its functional role in tumour pathogenesis has been hampered by the paucity of antibodies for its specific and sensitive detection. It has proven very difficult to obtain monoclonal antibodies (mAbs) against this highly conserved protein but we report here that combining infection of mice with lactate dehydrogenase elevating virus (LDV), a B cell activating arterivirus, with conjugation of human POSTN to ovalbumin as an immunogenic carrier, enabled us to develop six mAbs recognizing both human and mouse POSTN and inhibiting its binding to αvβ3 integrin. Two of the mAbs, MPB4B1 and MPC5B4, were tested and found to inhibit POSTN-induced migration of human endothelial colony forming cells. All six mAbs recognized amino acids 136-51 (APSNEAWDNLDSDIRR) within the POSTN fascilin (FAS) 1-1 domain revealing the functional importance of this motif; this was further highlighted by the ability of aa 136-151 peptide to inhibit integrin-mediated cell migration. Immunohistochemistry using MPC5B4, indicated that breast tumour cell POSTN expression was a strong prognostic indicator, along with tumour size, lymph node, and human epidermal growth factor receptor 2 (HER2) status.

Periostin activates pathways involved in epithelial-mesenchymal transition in adamantinomatous craniopharyngioma

Periostin (POSTN) is an extracellular matrix protein (ECM) critical for epithelial-mesenchymal transitions (EMT) in several kinds of tumor cells. Previous studies have indicated that EMT exists in craniopharyngioma (CP), and expression of POSTN is a significant factor in the prognosis of CP. However, it has never been explored whether POSTN exists in CP, or how it activates CP's EMT. The expression of POSTN was examined in adamantinomatous craniopharyngioma (ACP) primary cells and tissues by immunohistochemistry, PCR and Western blot, respectively. The effects and mechanisms of POSTN on ACP cells' EMT were also analyzed. It was found that POSTN expression increased in ACP-associated fibroblasts. Overexpressed POSTN significantly elevated the EMT of ACP cells by regulating the expression of associated genes. More importantly, our further study revealed that the upregulated POSTN activated Akt signaling pathway to regulate the EMT. This study showed that POSTN is responsible for the EMT of ACP cells, and POSTN might be a potential molecular therapeutic target for ACP treatment in future.

Targeting ECM Disrupts Cancer Progression

Metastatic complications are responsible for more than 90% of cancer-related deaths. The progression from an isolated tumor to disseminated metastatic disease is a multistep process, with each step involving intricate cross talk between the cancer cells and their non-cellular surroundings, the extracellular matrix (ECM). Many ECM proteins are significantly deregulated during the progression of cancer, causing both biochemical and biomechanical changes that together promote the metastatic cascade. In this review, the influence of several ECM proteins on these multiple steps of cancer spread is summarized. In addition, we highlight the promising (pre-)clinical data showing benefits of targeting these ECM macromolecules to prevent cancer progression.

Promotion of periostin expression contributes to the migration of Schwann cells

Neuregulin ligands and their ErbB receptors are important for the development of Schwann cells, the glial cells of the peripheral nervous system (PNS). ErbB3 deficiency is characterized by a complete loss of Schwann cells along axons of the peripheral nerves, impaired fasciculation and neuronal cell death. We performed comparative gene expression analysis of dorsal root ganglia (DRG) explant cultures from ErbB3-deficient and wild-type mice in order to identify genes that are involved in Schwann cell development and migration. The extracellular matrix (ECM) gene periostin was found to exhibit the most prominent down regulation in ErbB3-deficient DRG. Expression analysis revealed that the periostin-expressing cell population in the PNS corresponds to Schwann cell precursors and Schwann cells, and is particularly high in migratory Schwann cells. Furthermore, stimulation of Schwann cells with neuregulin-1 (NRG1) or transforming growth factor β (TGFβ-1) resulted in an upregulation of periostin expression. Interestingly, DRG explant cultures of periostin-deficient mice revealed a significant reduction of the number of migrating Schwann cells. These data demonstrate that the expression of periostin is stimulated by ErbB ligand NRG1 and influences the migration of Schwann cell precursors.

Periostin accelerates bone healing mediated by human mesenchymal stem cell-embedded hydroxyapatite/tricalcium phosphate scaffold

BACKGROUND

Periostin, an extracellular matrix protein, is expressed in bone, more specifically, the periosteum and periodontal ligaments, and plays a key role in formation and metabolism of bone tissues. Human adipose tissue-derived mesenchymal stem cells (hASCs) have been reported to differentiate into osteoblasts and stimulate bone repair. However, the role of periostin in hASC-mediated bone healing has not been clarified. In the current study, we examined the effect of periostin on bone healing capacity of hASCs in a critical size calvarial defect model.

METHODS AND RESULTS

Recombinant periostin protein stimulated migration, adhesion, and proliferation of hASCs in vitro. Implantation of either hASCs or periostin resulted in slight, but not significant, stimulation of bone healing, whereas co-implantation of hASCs together with periostin further potentiated bone healing. In addition, the number of Ki67-positive proliferating cells was significantly increased in calvarial defects by co-implantation of both hASCs and periostin. Consistently, proliferation of administered hASCs was stimulated by co-implantation with periostin in vivo. In addition, co-delivery of hASCs with periostin resulted in markedly increased numbers of CD31-positive endothelial cells and α-SMA-positive arterioles in calvarial defects.

CONCLUSIONS

These results suggest that recombinant periostin potentiates hASC-mediated bone healing by stimulating proliferation of transplanted hASCs and angiogenesis in calvarial defects.

Role of periostin and its antagonist PNDA-3 in gastric cancer metastasis

The extracellular matrix component periostin is a secreted protein that functions as both a cell attachment protein and an autocrine or paracrine factor that signals through the cell adhesion molecule integrins α_vβ₃ and α_vβ₅. Periostin participates in normal physiological activities such as cardiac development, but is also involved in pathophysiological processes in vascular diseases, wound repair, bone formation, and tumor development. It is of increasing interest in tumor biology because it is frequently overexpressed in a variety of epithelial carcinomas and is functionally involved in multiple steps of metastasis progression. These include the maintenance of stemness, niche formation, EMT, the survival of tumor cells, and angiogenesis, all of which are indispensable for gastric cancer metastasis. Periostin has been reported to activate the PI-3K/AKT, Wnt, and FAK-mediated signaling pathways to promote metastasis. Therefore, periostin represents a potentially promising candidate for the inhibition of metastasis. In this review article, we summarize recent advances in knowledge concerning periostin, its antagonist PNDA-3, and their influence on such key processes in cancer metastasis as maintenance of stemness, niche formation, epithelial-to-mesenchymal transition, tumor cell survival, and angiogenesis. In particular, we focus our attention on the role of periostin in gastric cancer metastasis, speculate as to the usefulness of periostin as a therapeutic and diagnostic target for gastric cancer metastasis, and consider potential avenues for future research.

Gene expression profiling-derived immunohistochemistry signature with high prognostic value in colorectal carcinoma

OBJECTIVE

Gene expression profiling provides an opportunity to develop robust prognostic markers of colorectal carcinoma (CRC). However, the markers have not been applied for clinical decision making. We aimed to develop an immunohistochemistry signature using microarray data for predicting CRC prognosis.

DESIGN

We evaluated 25 CRC gene signatures in independent microarray datasets with prognosis information and constructed a subnetwork using signatures with high concordance and repeatable prognostic values. Tumours were examined immunohistochemically for the expression of network-centric and the top overlapping molecules. Prognostic values were assessed in 682 patients from Shanghai, China (training cohort) and validated in 343 patients from Guangzhou, China (validation cohort). Median follow-up duration was 58 months. All p values are two-sided.

RESULTS

Five signatures were selected to construct a subnetwork. The expression of GRB2, PTPN11, ITGB1 and POSTN in cancer cells, each significantly associated with disease-free survival, were selected to construct an immunohistochemistry signature. Patients were dichotomised into high-risk and low-risk subgroups with an optimal risk score (1.55). Compared with low-risk patients, high-risk patients had shorter disease-specific survival (DSS) in the training (HR=6.62; 95% CI 3.70 to 11.85) and validation cohorts (HR=3.53; 95% CI 2.13 to 5.84) in multivariate Cox analyses. The signature better predicted DSS than did tumour-node-metastasis staging in both cohorts. In those who received postoperative chemotherapy, high-risk score predicted shorter DSS in the training (HR=6.35; 95% CI 3.55 to 11.36) and validation cohorts (HR=5.56; 95% CI 2.25 to 13.71).

CONCLUSIONS

Our immunohistochemistry signature may be clinically practical for personalised prediction of CRC prognosis.

Periostin in skin tissue and skin-related diseases

Extracellular matrix (ECM) is not only involved in the maintenance of normal physiological tissue but also in interactions with other ECM components, tissue remodeling, and modulating immune responses. The skin provides a distinctive environment characterized by rich fibroblasts producing various ECM proteins, epithelial-mesenchymal interactions, and immune responses induced by external stimuli. Recently, periostin-a matricellular protein-has been highlighted for its pivotal functions in the skin. Analysis of periostin null mice has revealed that periostin contributes to collagen fibrillogenesis, collagen cross-linking, and the formation of ECM meshwork via interactions with other ECM components. Periostin expression is enhanced by mechanical stress or skin injury; this is indicative of the physiologically protective functions of periostin, which promotes wound repair by acting on keratinocytes and fibroblasts. Along with its physiological functions, periostin plays pathogenic roles in skin fibrosis and chronic allergic inflammation. In systemic sclerosis (SSc) patients, periostin levels reflect the severity of skin fibrosis. Periostin null mice have shown reduced skin fibrosis in a bleomycin-induced SSc mouse model, indicating a key role of periostin in fibrosis. Moreover, in atopic dermatitis (AD), attenuated AD phenotype has been observed in periostin null mice in a house dust mite extract-induced AD mouse model. Th2 cytokine-induced periostin acts on keratinocytes to produce inflammatory cytokines that further enhance the Th2 response, thereby sustaining and amplifying chronic allergic inflammation. Thus, periostin is deeply involved in the pathogenesis of AD and other inflammation-related disorders affecting the skin. Understanding the dynamic actions of periostin would be key to dissecting pathogenesis of skin-related diseases and to developing novel therapeutic strategies.

The expression and immunohistochemical localization of periostin in odontogenic tumors of mixed epithelial/mesenchymal origin

OBJECTIVE

The object of this study was to determine the expression and localization of periostin in the major mixed odontogenic tumors and to correlate any differential staining of the mesenchymal components to the interrelationship of these tumors.

STUDY DESIGN

Five ameloblastic fibromas, 8 ameloblastic fibro-odontomas and 10 odontomas were assessed immunohistochemically for periostin staining. Because mesenchymal tissues were consistently present in all studied cases, these tissues were selected for statistical analysis of differential periostin staining.

RESULTS

Periostin was variably localized to the mesenchymal component of the tumors as well as to preameloblasts and ameloblasts. Analysis of the mesenchymal staining intensity was statistically significantly different between ameloblastic fibro-odontomas and odontomas (P < .001; Dunn multiple comparisons test).

CONCLUSIONS

Our results document periostin staining in human mixed odontogenic tumors. Statistical analysis of differential stromal staining supports the concept that the ameloblastic fibroma is a histogenetically distinct neoplasm as compared to ameloblastic fibro-odontoma and odontoma.

Periostin: a novel prognostic and therapeutic target for genitourinary cancer?

Many of the cellular abnormalities present in solid tumors are structural in nature and involve the proteins of the extracellular matrix (ECM). Periostin is a protein produced and secreted by the fibroblasts as a component of the ECM where it is involved in regulating intercellular adhesion. The expression of periostin has an important physiological role during embryogenesis and growth, namely at the level of bone, dental, and cardiac tissues. Many studies indicate that periostin plays an important role for tumor progression in various types of cancer, such as colon, lung, head and neck, breast, ovarian, and prostate. To the best of our knowledge, a limited number of studies have investigated periostin expression in urogenital cancer, such as prostate, bladder, penile, and renal cancer, and no studies were performed in testis cancer. In this review article, we summarize the most recent knowledge of periostin, its genetic and protein structure, and the role of the different isoforms identified and sequenced so far. In particular, we focus our attention on the role of this protein in genitourinary tumors, trying to emphasize the role not only as a possible prognostic marker, but also as a possible target for the development of future anticancer therapies.

Periostin promotes renal cyst growth and interstitial fibrosis in polycystic kidney disease

In renal cystic diseases, sustained enlargement of fluid-filled cysts is associated with severe interstitial fibrosis and progressive loss of functioning nephrons. Periostin, a matricellular protein, is highly overexpressed in cyst-lining epithelial cells of autosomal-dominant polycystic disease kidneys (ADPKD) compared with normal tubule cells. Periostin accumulates in situ within the matrix subjacent to ADPKD cysts, binds to αVβ3 and αVβ5 integrins, and stimulates the integrin-linked kinase to promote cell proliferation. We knocked out periostin (Postn) in pcy/pcy mice, an orthologous model of nephronophthisis type 3, to determine whether periostin loss reduces PKD progression in a slowly progressive model of renal cystic disease. At 20 weeks of age, pcy/pcy:Postn(-/-) mice had a 34% reduction in kidney weight/body weight, a reduction in cyst number and total cystic area, a 69% reduction in phosphorylated S6, a downstream component of the mTOR pathway, and fewer proliferating cells in the kidneys compared with pcy/pcy:Postn(+/+) mice. The pcy/pcy Postin knockout mice also had less interstitial fibrosis with improved renal function at 20 weeks and significantly longer survival (51.4 compared with 38.0 weeks). Thus, periostin adversely modifies the progression of renal cystic disease by promoting cyst epithelial cell proliferation, cyst enlargement, and interstitial fibrosis, all contributing to the decline in renal function and premature death.

Overexpression of periostin predicts poor prognosis in non-small cell lung cancer

The periostin protein, encoded by the POSTN gene, is a component of the extracellular matrix, which is expressed by fibroblasts and has been observed in a variety of human malignancies. The present study aimed to detect the expression of periostin in the tissues of non-small cell lung cancer (NSCLC) patients and benign lung tumors, and to correlate the results with the clinicopathological data of the subjects, in order to evaluate periostin as a potential prognostic marker. In total, 49 NSCLC patients and 6 benign lung tumors were included in this study. The protein level of periostin was detected in paired normal/paratumor/cancer tissues by a western blot analysis and the mRNA level in paired normal/cancer tissues was detected by quantitative polymerase chain reaction (qPCR). The results were then correlated with established biological and prognostic factors. Immunohistochemistry was used to confirm the location of periostin in the NSCLC tissues. Uni- and multivariate analyses were performed using Cox's proportional hazards regression model. The protein level of periostin was elevated in the cancer tissue of the NSCLC patients compared with the normal (P=0.017) and paratumor (P=0.000) tissues. The expression level in the male patients was much higher than in the female patients at the protein (P=0.001) and mRNA (P=0.010) levels. The mRNA level in the non-adenocarcinoma (non-ADC) patients was much higher than in the adenocarcinoma (ADC) patients (P=0.029). Periostin was demonstrated higher expression at the protein level in the pseudotumors and tuberculosis patients than in the adjacent (P=0.016) and surrounding tissues (P=0.001). Immunostaining indicated that high levels of periostin were present in the mesenchymal areas, but not in the cancer cells themselves. The patients with tumors exhibiting high-level periostin expression showed a significantly shorter survival time (P=0.036, log-rank test). The 3-year survival rate was 81.5% for patients with low-level periostin expression (periostin-L; n=27) and 45.4% for patients with high-level periostin expression (periostin-H; n=22). Similarly, pathological node (pN) status was a significant prognostic marker in the univariate Cox survival analysis. Notably, periostin-H expression was also identified as an independent prognostic factor by the multivariate analysis (P=0.011). These results showed that the overexpression of periostin predicts a poor prognosis, therefore it may be regarded as a novel molecule in the progression and development of NSCLC. The results provide an additional target for the adjuvant treatment of NSCLC.

High-level expression of periostin is closely related to metastatic potential and poor prognosis of hepatocellular carcinoma

Periostin (PN) is a kind of secreted glycoprotein, which is closely related to the metastatic potential and prognosis of many kinds of tumors in recent studies. However, the expression level of PN in hepatocellular carcinoma (HCC) and its correlation with tumor angiogenesis and prognosis remain unclear. Here Immunohistochemistry assay was used to determine the expression of PN in HCC and corresponding adjacent tissues from 71 patients. VEGF and CD34 were only examined in HCC tissues of patients mentioned above. Immunohistochemically, the expression of PN in HCC was judged to be positive in 73.2 % (52/71) compared with 19.7 % (14/71) in corresponding adjacent tissues, and it was associated with tumor nodules (P = 0.070), microvascular invasion (P = 0.013), Edmondson grade (P = 0.003), tumor capsula (P = 0.038) and TNM stage (P = 0.000); besides, tumors with PN-positive group expressed higher VEGF (82.7 vs. 26.3 %, χ (2) = 20.195, P = 0.000) and had higher MVD (80.5 ± 36.5 vs. 24.0 ± 19.9, t = -6.395, P = 0.000) than those in PN-negative group. Kaplan-Meier method was used for survival analysis, and Cox regression model was performed for multivariate survival analysis. In particular, the expression of PN was found to be an independent factor for predicting overall and disease-free survival of HCC. It is possible that the expression level of PN in HCC is associated with tumor metastatic potential and angiogenesis. Its abnormal expression could be a predictive factor to anticipate HCC patient's prognosis after surgery.

Upregulation of periostin prevents P53-mediated apoptosis in SGC-7901 gastric cancer cells

Periostin is frequently upregulated in human cancers including gastric cancer and implicated in cancer cell proliferation, invasion, and epithelial-mesenchymal transition. This study was undertaken to investigate the effects of periostin overexpression on the chemosensitivity of gastric cancer cells. We constructed a stable cell line overexpressing periostin in SGC-7901 human gastric cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that periostin had no influence on the proliferation of SGC-7901 cells. Compared to empty vector-transfected cells, overexpression of periostin rendered SGC-7901 cells more resistant to cisplatin or 5-fluorouracil (5-FU)-induced apoptosis, accompanying with less release of cytochrome c from mitochondria and diminished cleavage of caspase-3 and poly (ADP-ribose) polymerase. Periostin-overexpressing cells treated with cisplatin or 5-FU showed significantly (p < 0.05) decreased expression of Bax and p53 proteins and increased expression of Bcl-2 protein, when compared to drug-treated mock counterparts. Restoration of p53 expression by delivering wild-type p53 gene resulted in a marked increase in drug-induced apoptosis in periostin-overexpressing SGC-7901 cells. Periostin overexpression elevated the phosphorylation of Akt. Pretreatment of periostin-overexpressing cells with an Akt inhibitor, MK-2206, partially rescued periostin-mediated inhibition of p53 expression and drug resistance. Taken together, our data indicate that periostin confers protection against cisplatin or 5-FU-induced apoptosis in SGC-7901 cells, likely through modulating the Akt/p53 pathway, and thus represents a potential therapeutic target in gastric cancer.

Periostin promotes fibrosis and predicts progression in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease without effective therapeutics. Periostin has been reported to be elevated in IPF patients relative to controls, but its sources and mechanisms of action remain unclear. We confirm excess periostin in lungs of IPF patients and show that IPF fibroblasts produce periostin. Blood was obtained from 54 IPF patients (all but 1 with 48 wk of follow-up). We show that periostin levels predict clinical progression at 48 wk (hazard ratio = 1.47, 95% confidence interval = 1.03-2.10, P < 0.05). Monocytes and fibrocytes are sources of periostin in circulation in IPF patients. Previous studies suggest that periostin may regulate the inflammatory phase of bleomycin-induced lung injury, but periostin effects during the fibroproliferative phase of the disease are unknown. Wild-type and periostin-deficient (periostin(-/-)) mice were anesthetized and challenged with bleomycin. Wild-type mice were injected with bleomycin and then treated with OC-20 Ab (which blocks periostin and integrin interactions) or control Ab during the fibroproliferative phase of disease, and fibrosis and survival were assessed. Periostin expression was upregulated quickly after treatment with bleomycin and remained elevated. Periostin(-/-) mice were protected from bleomycin-induced fibrosis. Instillation of OC-20 during the fibroproliferative phase improved survival and limited collagen deposition. Chimeric mouse studies suggest that hematopoietic and structural sources of periostin contribute to lung fibrogenesis. Periostin was upregulated by transforming growth factor-β in lung mesenchymal cells, and periostin promoted extracellular matrix deposition, mesenchymal cell proliferation, and wound closure. Thus periostin plays a vital role in late stages of pulmonary fibrosis and is a potential biomarker for disease progression and a target for therapeutic intervention.

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.

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.

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.

Negative transcriptional regulation of the human periostin gene by YingYang-1 transcription factor

Periostin (POSTN), an osteoblast-specific secreted protein known to be associated with cell adhesion activity for bone formation and development by the epithelial cell-derived tumors, leads to a significant enhancement in angiogenesis and tumorigenesis. At present, little is known about the mechanisms underlying its transcriptional control either in physiological or neoplastic conditions. In this study we demonstrate that the ability of the human POSTN promoter to drive transcription mostly depends on the activity of YingYang-1 (YY1) zinc finger transcription factor. YY1, whose regulatory role in biology includes, besides transcriptional control, also chromatin remodeling, DNA damage repair and tumorigenesis, acts as a strong negative modulator of the POSTN expression. We retain that the identification of the functional role of YY1 in the transcriptional control of the human POSTN gene adds new insights in the studies focused on gene expression in normal and transformed cells.

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.

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.

Cancer-associated fibroblasts in intrahepatic cholangiocarcinoma

PURPOSE OF REVIEW

The aim of this brief review is to provide an up-to-date view of the role played by α-smooth muscle actin-positive cancer-associated fibroblastic cells in promoting intrahepatic cholangiocarcinoma progression.

RECENT FINDINGS

An increase in α-smooth muscle actin-positive cancer-associated fibroblastic cells in the stroma of intrahepatic cholangiocarcinoma has recently been demonstrated to accelerate cholangiocarcinoma progression. However, our understanding of the evolving cellular and molecular interactions between these stromal cells and cholangiocarcinoma cells in relation to promoting intrahepatic cholangiocarcinoma progression is only just beginning to be elucidated. Imbalances in multifactorial growth factor/cytokine signaling, activation of Hedgehog-GLI signaling and of proteases involved in extracellular matrix remodeling, and matricellular protein-protein and protein-cholangiocarcinoma cell interactions, as well as hypoxia, all appear to factor into the complex and dynamic interactive mechanisms through which cancer-associated fibroblastic cells crosstalk with cholangiocarcinoma cells to promote intrahepatic cholangiocarcinoma progression. Novel three-dimensional organotypic co-culture models are being developed to facilitate relevant studies of cancer-associated fibroblastic cell/cholangiocarcinoma cell interactions that may more accurately mimic physiologically pertinent features of the tumor.

SUMMARY

Increasing our understanding of critical interactive pathways by which cancer-associated fibroblastic cells crosstalk with cholangiocarcinoma cells to promote tumor progression can lead to the development of novel multitargeting strategies for intrahepatic cholangiocarcinoma therapy.