Emerging functions of matricellular proteins

Beyond the Norm: The emerging interplay of complement system and extracellular matrix in the tumor microenvironment

Ground-breaking awareness has been reached about the intricate and dynamic connection between developing tumors and the host immune system. Being a powerful arm of innate immunity and a functional bridge with adaptive immunity, the complement system (C) has also emerged as a pivotal player in the tumor microenvironment (TME). Its "double-edged sword" role in cancer can find an explanation in the controversial relationship between C capability to mediate tumor cell cytolysis or, conversely, to sustain chronic inflammation and tumor progression by enhancing cell invasion, angiogenesis, and metastasis to distant organs. However, comprehensive knowledge about the actual role of C in cancer progression is impaired by several limitations of the currently available studies. In the current review, we aim to bring a fresh eye to the controversial role of C in cancer by analyzing the interplay between C and extracellular matrix (ECM) components as potential orchestrators of the TME. The interaction of C components with specific ECM components can determine C activation or inhibition and promote specific non-canonical functions, which can, in the tumor context, favor or limit progression based on the cancer setting. An in-depth and tumor-specific characterization of TME composition in terms of C components and ECM proteins could be essential to determine their potential interactions and become a key element for improving drug development, prognosis, and therapy response prediction in solid tumors.

Intact Fish Skin Graft to Treat Deep Diabetic Foot Ulcers

BACKGROUND

Diabetic foot ulcers are chronic, difficult to heal, and potentially life-threatening. Few medical devices have been studied in diabetic ulcers penetrating to bone or tendon.

METHODS

We conducted an international, open-label randomized controlled trial, randomly assigning patients with diabetic ulcers penetrating to bone, joint, or tendon 1:1 to intact fish skin graft or standard wound care, with assigned treatment applied through 14 weeks. The primary end point was the proportion of ulcers healed at 16 weeks, defined as reepithelization as identified by the investigator, and confirmed 14 days later. A blinded adjudication committee confirmed healing at both time points. Healing was also assessed at 20 and 24 weeks.

RESULTS

Between July 2020 and November 2022, 255 patients were randomly assigned to intact fish skin graft (n=129) or standard of care (n=126). Healing was achieved in 44% of patients at 16 weeks with intact fish skin graft compared with 26% for standard of care (P<0.001, unadjusted), with additional healing at 20 weeks (46% vs. 32%) and 24 weeks (55% vs. 38%). Mean (SD) time to healing was 17.3 (0.69) weeks (95% confidence interval [CI], 15.5 to 18.7) for the intact fish skin graft group and 19.4 (0.66) weeks (95% CI, 18.1 to 20.7) for the standard of care group. In a Cox regression, intact fish skin graft was associated with faster time to healing (hazard ratio, 1.59; 95% CI, 1.07 to 2.36). Primary wound infections were the most common adverse event, occurring in 39 (30.2%) of patients in the intact fish skin graft group and 31 (24.6%) of patients in the standard of care group.

CONCLUSIONS

Among patients with deep diabetic foot ulcers, treatment with intact fish skin graft was superior to standard of care in proportion of wounds healed at 16 weeks and was associated with faster time to healing. (Funded by European Commission Fast Track to Innovation Horizon 2020, and Kerecis Ltd. ClinicalTrials.gov NCT04257370.).

SPOCK: Master regulator of malignant tumors (Review)

SPARC/osteonectin, CWCV and Kazal‑like domain proteoglycan (SPOCK) is a family of highly conserved multidomain proteins. In total, three such family members, SPOCK1, SPOCK2 and SPOCK3, constitute the majority of extracellular matrix glycoproteins. The SPOCK gene family has been demonstrated to serve key roles in tumor regulation by affecting MMPs, which accelerates the progression of cancer epithelial‑mesenchymal transition. In addition, they can regulate the cell cycle via overexpression, inhibit tumor cell proliferation by inactivating PI3K/AKT signaling and have been associated with numerous microRNAs that influence the expression of downstream genes. Therefore, the SPOCK gene family are potential cancer‑regulating genes. The present review summarizes the molecular structure, tissue distribution and biological function of the SPOCK family of proteins, in addition to its association with cancer. Furthermore, the present review documents the progress made in investigations into the role of SPOCK, whilst also discussing prospects for the future of SPOCK‑targeted therapy, to provide novel ideas for clinical application and treatment.

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.

CYR61 promotes colorectal carcinoma progression via activating epithelial-mesenchymal transition

Colorectal carcinoma is the third most common type of cancer. Although the role of matricellular proteins and their association with tumor progression is well documented, limited data are available concerning their involvement in colorectal cancer. The current study investigated the expression pattern of matricellular proteins SPARC and CYR61 with epithelial-mesenchymal transition proteins in human CRC tissues and unleashed their association with colorectal cancer progression. The expression of these proteins was associated with advancement in tumor staging, nodal metastasis, and vascular invasion. Elevated CYR61 protein levels were also consistent with higher mesenchymal markers ZEB1 and Vimentin in collected biopsies and CRC cells. Moreover, expression of CYR61 promoted CRC cell migration, invasion, proliferation, and apoptosis. Our findings conclusively revealed the significant involvement of CYR61 in CRC progression through activating epithelial-mesenchymal transition. This discovery holds great promise for advancing therapeutic approaches in the treatment of CRC.

Methadone alters transcriptional programs associated with synapse formation in human cortical organoids

Opioid use disorder (OUD) among pregnant women has become an epidemic in the United States. Pharmacological interventions for maternal OUD most commonly involve methadone, a synthetic opioid analgesic that attenuates withdrawal symptoms and behaviors linked with drug addiction. However, evidence of methadone's ability to readily accumulate in neural tissue, and cause long-term neurocognitive sequelae, has led to concerns regarding its effect on prenatal brain development. We utilized human cortical organoid (hCO) technology to probe how this drug impacts the earliest mechanisms of cortico-genesis. Bulk mRNA sequencing of 2-month-old hCOs chronically treated with a clinically relevant dose of 1 μM methadone for 50 days revealed a robust transcriptional response to methadone associated with functional components of the synapse, the underlying extracellular matrix (ECM), and cilia. Co-expression network and predictive protein-protein interaction analyses demonstrated that these changes occurred in concert, centered around a regulatory axis of growth factors, developmental signaling pathways, and matricellular proteins (MCPs). TGFβ1 was identified as an upstream regulator of this network and appeared as part of a highly interconnected cluster of MCPs, of which thrombospondin 1 (TSP1) was most prominently downregulated and exhibited dose-dependent reductions in protein levels. These results demonstrate that methadone exposure during early cortical development alters transcriptional programs associated with synaptogenesis, and that these changes arise by functionally modulating extra-synaptic molecular mechanisms in the ECM and cilia. Our findings provide novel insight into the molecular underpinnings of methadone's putative effect on cognitive and behavioral development and a basis for improving interventions for maternal opioid addiction.

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.

BMPER Improves Vascular Remodeling and the Contractile Vascular SMC Phenotype

Dedifferentiated vascular smooth muscle cells (vSMCs) play an essential role in neointima formation, and we now aim to investigate the role of the bone morphogenetic protein (BMP) modulator BMPER (BMP endothelial cell precursor-derived regulator) in neointima formation. To assess BMPER expression in arterial restenosis, we used a mouse carotid ligation model with perivascular cuff placement. Overall BMPER expression after vessel injury was increased; however, expression in the tunica media was decreased compared to untreated control. Consistently, BMPER expression was decreased in proliferative, dedifferentiated vSMC in vitro. C57BL/6_Bmper+/- mice displayed increased neointima formation 21 days after carotid ligation and enhanced expression of Col3A1, MMP2, and MMP9. Silencing of BMPER increased the proliferation and migration capacity of primary vSMCs, as well as reduced contractibility and expression of contractile markers, whereas stimulation with recombinant BMPER protein had the opposite effect. Mechanistically, we showed that BMPER binds insulin-like growth factor-binding protein 4 (IGFBP4), resulting in the modulation of IGF signaling. Furthermore, perivascular application of recombinant BMPER protein prevented neointima formation and ECM deposition in C57BL/6N mice after carotid ligation. Our data demonstrate that BMPER stimulation causes a contractile vSMC phenotype and suggest that BMPER has the potential for a future therapeutic agent in occlusive cardiovascular diseases.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

Matricellular protein tenascin C: Implications in glioma progression, gliomagenesis, and treatment

Matricellular proteins are nonstructural extracellular matrix components that are expressed at low levels in normal adult tissues and are upregulated during development or under pathological conditions. Tenascin C (TNC), a matricellular protein, is a hexameric and multimodular glycoprotein with different molecular forms that is produced by alternative splicing and post-translational modifications. Malignant gliomas are the most common and aggressive primary brain cancer of the central nervous system. Despite continued advances in multimodal therapy, the prognosis of gliomas remains poor. The main reasons for such poor outcomes are the heterogeneity and adaptability caused by the tumor microenvironment and glioma stem cells. It has been shown that TNC is present in the glioma microenvironment and glioma stem cell niches, and that it promotes malignant properties, such as neovascularization, proliferation, invasiveness, and immunomodulation. TNC is abundantly expressed in neural stem cell niches and plays a role in neurogenesis. Notably, there is increasing evidence showing that neural stem cells in the subventricular zone may be the cells of origin of gliomas. Here, we review the evidence regarding the role of TNC in glioma progression, propose a potential association between TNC and gliomagenesis, and summarize its clinical applications. Collectively, TNC is an appealing focus for advancing our understanding of gliomas.

Defining the versican interactome in lung health and disease

The extracellular matrix (ECM) imparts critical mechanical and biochemical information to cells in the lungs. Proteoglycans are essential constituents of the ECM and play a crucial role in controlling numerous biological processes, including regulating cellular phenotype and function. Versican, a chondroitin sulfate proteoglycan required for embryonic development, is almost absent from mature, healthy lungs and is reexpressed and accumulates in acute and chronic lung disease. Studies using genetically engineered mice show that the versican-enriched matrix can be pro- or anti-inflammatory depending on the cellular source or disease process studied. The mechanisms whereby versican develops a contextual ECM remain largely unknown. The primary goal of this review is to provide an overview of the interaction of versican with its many binding partners, the "versican interactome," and how through these interactions, versican is an integrator of complex extracellular information. Hopefully, the information provided in this review will be used to develop future studies to determine how versican and its binding partners can develop contextual ECMs that control select biological processes. Although this review focuses on versican and the lungs, what is described can be extended to other proteoglycans, tissues, and organs.

Transcription factor Runx2 changes the expression of some matricellular proteins in metastatic breast cancer cells

BACKGROUND

Runx2 is one of the runt-related genes that are overexpressed in human cancers and contribute to metastasis. The cancer cell metastasis requires modifications of the extracellular matrix (ECM) and reduction in ECM-cell interaction. This process is performed by various enzymes and proteins secreted by cancer and surrounding cells. This study aimed to investigate the effect of the Runx2 transcription factor on the expression of matricellular proteins such as HPA1, LOX, SPARC, and OPN, which have important roles in ECM modification and ECM-cell interaction in human breast cancer. Also, the changes in their associated oncogenic pathways including Akt, Erk, FAK activities, and c-jun protein expression were investigated.

METHODS AND RESULTS

Runx2 knockdown model was created using runx2 siRNA in MDA-MB-231 human metastatic breast cancer cells. The changes in the mRNA and protein expressions of ECM proteins were shown by the qPCR and Western blotting, respectively. The results showed that there was a decrease in both mRNA and protein expressions of HPA1, SPARC, and LOX, whereas there was no change in those of OPN. Phosphorylated Akt, Erk, FAK levels, and protein expression of c-jun, however, decreased in the cells.

CONCLUSION

Our results revealed that Runx2 affected matricellular protein expression, which is important for metastasis and invasion of breast cancer. Hence, we have concluded that runx2 appears to be efficient for regulating breast cancer metastasis through an expression of matricellular proteins.

Comprehensive Analysis of Cardiac Xeno-Graft Unveils Rejection Mechanisms

Porcine heart xenotransplantation is a potential treatment for patients with end-stage heart failure. To understand molecular mechanisms of graft rejection after heart transplantation, we transplanted a 31-day-old alpha-1,3-galactosyltransferase knockout (GTKO) porcine heart to a five-year-old cynomolgus monkey. Histological and transcriptome analyses were conducted on xenografted cardiac tissue at rejection (nine days after transplantation). The recipient monkey's blood parameters were analyzed on days -7, -3, 1, 4, and 7. Validation was conducted by quantitative real-time PCR (qPCR) with selected genes. A non-transplanted GTKO porcine heart from an age-matched litter was used as a control. The recipient monkey showed systemic inflammatory responses, and the rejected cardiac graft indicated myocardial infarction and cardiac fibrosis. The transplanted heart exhibited a total of 3748 differentially expressed genes compared to the non-transplanted heart transcriptome, with 2443 upregulated and 1305 downregulated genes. Key biological pathways involved at the terminal stage of graft rejection were cardiomyopathies, extracellular interactions, and ion channel activities. The results of qPCR evaluation were in agreement with the transcriptome data. Transcriptome analysis of porcine cardiac tissue at graft rejection reveals dysregulation of the key molecules and signaling pathways, which play relevant roles on structural and functional integrities of the heart.

Gene expression profile of adhesion and extracellular matrix molecules during early stages of skeletal muscle regeneration

Skeletal muscle regeneration implies the coordination of myogenesis with the recruitment of myeloid cells and extracellular matrix (ECM) remodelling. Currently, there are no specific biomarkers to diagnose the severity and prognosis of muscle lesions. In order to investigate the gene expression profile of extracellular matrix and adhesion molecules, as premises of homo‐ or heterocellular cooperation and milestones for skeletal muscle regeneration, we performed a gene expression analysis for genes involved in cellular cooperation, migration and ECM remodelling in a mouse model of acute crush injury. The results obtained at two early time‐points post‐injury were compared to a GSE5413 data set from two other trauma models. Third day post‐injury, when inflammatory cells invaded, genes associated with cell‐matrix interactions and migration were up‐regulated. After day 5, as myoblast migration and differentiation started, genes for basement membrane constituents were found down‐regulated, whereas genes for ECM molecules, macrophage, myoblast adhesion, and migration receptors were up‐regulated. However, the profile and the induction time varied according to the experimental model, with only few genes being constantly up‐regulated. Gene up‐regulation was higher, delayed and more diverse following more severe trauma. Moreover, one of the most up‐regulated genes was periostin, suggestive for severe muscle damage and unfavourable architecture restoration.

The Matrix Revolution: Matricellular Proteins and Restructuring of the Cancer Microenvironment

The extracellular matrix (ECM) surrounding cells is indispensable for regulating their behavior. The dynamics of ECM signaling are tightly controlled throughout growth and development. During tissue remodeling, matricellular proteins (MCP) are secreted into the ECM. These factors do not serve classical structural roles, but rather regulate matrix proteins and cell-matrix interactions to influence normal cellular functions. In the tumor microenvironment, it is becoming increasingly clear that aberrantly expressed MCPs can support multiple hallmarks of carcinogenesis by interacting with various cellular components that are coupled to an array of downstream signals. Moreover, MCPs also reorganize the biomechanical properties of the ECM to accommodate metastasis and tumor colonization. This realization is stimulating new research on MCPs as reliable and accessible biomarkers in cancer, as well as effective and selective therapeutic targets.

Periostin and Human Teeth

Periostin is a secreted matricellular protein that primarily interacts with type I collagen and fibronectin extracellular matrix proteins, and is widely distributed in tissues rich in collagen-rich connective tissues, including the periodontal ligament. Its expression in these tissues is especially regulated by mechanical load. While the expression and regulation of periostin in the teeth of murine models and cell lines is well known, its presence in human teeth is poorly documented. Here we update and summarize the available data on the distribution of periostin in the human periodontal ligament, gingiva and dental pulp.

Periostin induces kidney fibrosis after acute kidney injury via the p38 MAPK pathway

Periostin plays a crucial role in fibrosis, and acute kidney injury results in a high risk of progression to chronic kidney disease. Therefore, we hypothesized that periostin was involved in the progression of acute kidney injury to kidney fibrosis. Unilateral ischemia-reperfusion injury (UIRI) was induced in 7- to 8-wk-old male wild-type and periostin-null mice, and the animals were observed for 6 wk. In vitro, human kidney-2 cells and primary-cultured human tubular epithelial cells were incubated under hypoxic conditions (5% O₂, 5% CO₂, and 90% N₂) for 5 days. The cells were also cultured with recombinant periostin (rPeriostin) and a p38 mitogen-activated protein kinase (MAPK) inhibitor in a hypoxic incubator. At 6 wk after UIRI, interstitial fibrosis/tubular atrophy was significantly alleviated in periostin-null mice compared with wild-type controls. In addition, periostin-null mice had attenuated expression of fibrosis/apoptosis markers and phosphorylated-p38 MAPK compared with wild-type controls. In vitro, hypoxic injury increased the expression of fibrosis markers, periostin, and phosphorylated-p38 MAPK, which was comparable to or substantially greater than their expression levels following treatment with recombinant transforming growth factor-β1 under normoxic conditions. Furthermore, rPeriostin treatment under hypoxic conditions enhanced fibrosis/apoptosis markers and phosphorylated-p38 MAPK. In contrast, p38 MAPK inhibition ameliorated hypoxia-induced fibrosis, and the addition of the p38 MAPK inhibitor to rPeriostin significantly ameliorated the changes induced by rPeriostin. In conclusion, periostin promotes kidney fibrosis via the p38 MAPK pathway following acute kidney injury triggered by a hypoxic or ischemic insult. Periostin ablation may protect against chronic kidney disease progression.

Amelioration of collagen antibody induced arthritis in mice by an antibody directed against the fibronectin type III repeats of tenascin-C: Targeting fibronectin type III repeats of tenascin-C in rheumatoid arthritis

Tenascin-C (TN-C) levels are elevated in the synovial tissue and fluid, as well as cartilage of rheumatoid arthritis (RA) patients. In addition, the presence of TN-C fragments has also been documented in arthritic cartilage. We have previously shown that a single chain variable fragment antibody (TN64), directed against the fibronectin type III repeats 1-5 (TNfnIII 1-5) of TN-C, effectively inhibits fibrotic pathology. Given that fibrosis results from chronic inflammation, and the fact that increased levels of TN-C in the synovial fluid of patients with RA contributes to synovial inflammation and joint destruction, we aimed to investigate the role of TNfnIII 1-5 region of TN-C in RA pathogenesis. Using either the wild type or variants of the two integrin-binding motifs (RGD and AEIDGIEL) present within the TNfnIII 1-5 polypeptide, we demonstrate that the adhesion and migration of synovial fibroblasts is RGD-dependent. The antibody TN64 is effective in inhibiting migration of cells in response to TnfnIII 1-5, and prevents fibroblast-mediated destruction of cartilage. The TN64 antibody was further tested in collagen antibody induced arthritic (CAIA) mice. Our data shows the efficacy of TN64 in preventing induction of arthritis, with significant downregulation of RA-associated cytokines. This suggests that components of the extracellular matrix such as the TNfnIII 1-5 region of TN-C could be exploited to develop therapies to suppress inflammation seen in RA. The TN64 antibody is one such promising candidate in the development of novel treatments for RA.

Modulating secreted components of tumor microenvironment: A masterstroke in tumor therapeutics

The microenvironment in which cancer resides plays an important role in regulating cancer survival, progression, malignancy and drug resistance. Tumor microenvironment (TME) consists of heterogeneous number and types of cellular and non-cellular components that vary in relation to tumor phenotype and genotype. In recent, non-cellular secreted components of microenvironmental heterogeneity have been suggested to contain various growth factors, cytokines, RNA, DNA, metabolites, structural matrix and matricellular proteins. These non-cellular components have been indicated to orchestrate numerous ways to support cancer survival and progression by providing metabolites, energy, growth signals, evading immune surveillance, drug resistance environment, metastatic and angiogenesis cues. Thus, switching action from pro-cancer to anti-cancer activities of these secreted components of TME has been considered as a new avenue in cancer therapeutics and drug resistance. In this report, we summarize the recent pre-clinical and clinical evidences to emphasize the importance of non-cellular components of TME in achieving precision therapeutics and biomarker study.

Matricellular proteins and survival in patients with pancreatic cancer: A systematic review

Extracellular matrix (ECM) plays a fundamental role in tissue architecture and homeostasis and modulates cell functions through a complex interaction between cell surface receptors, hormones, several bioeffector molecules, and structural proteins like collagen. These components are secreted into ECM and all together contribute to regulate several cellular activities including differentiation, apoptosis, proliferation, and migration. The so-called "matricellular" proteins (MPs) have recently emerged as important regulators of ECM functions. The aim of our review is to consider all different types of MPs family assessing the potential relationship between MPs and survival in patients with pancreatic ductal adenocarcinoma (PDAC). A systematic computer-based search of published articles, according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) Statement issued in 2009 was conducted through Ovid interface, and literature review was performed in May 2017. The search text words were identified by means of controlled vocabulary, such as the National Library of Medicine's MESH (Medical Subject Headings) and Keywords. Collected data showed an important role of MPs in carcinogenesis and in PDAC prognosis even though the underlying mechanisms are still largely unknown and data are not univocal. Therefore, a better understanding of MPs role in regulation of ECM homeostasis and remodeling of specific organ niches may suggest potential novel extracellular targets for the development of efficacious therapeutic strategies.

Do the expressions of epithelial-mesenchymal transition proteins, periostin, integrin-α4 and fibronectin correlate with clinico-pathological features and prognosis of metastatic castration-resistant prostate cancer?

Development of metastatic castration-resistant prostate cancer is a result of the lack of an apoptotic response by the tumor cells and loss of the ability to stick to adjacent cells through epithelial-mesenchymal transition. Although there are several strongly recommended biomarkers for determining prognosis of metastatic castration-resistant prostate cancer, only few of them may help decide the selection of the optimal treatment option. The mode of treatment sequencing in metastatic castration-resistant prostate cancer will be based on the individual characteristics of the patient. In this study, we aimed to explain the correlation between the expression characteristics of periostin, integrin-α4, and fibronectin in metastatic castration-resistant prostate cancer patients and their clinico-pathological data comprising Gleason score, PSA levels, and metastatic sites in the process of epithelial-mesenchymal transition. We evaluated by using Western blotting, periostin, integrin-α4, and fibronectin expressions in peripheral blood samples of metastatic castration-resistant prostate cancer patients ( n = 40), benign prostatic hyperplasia patients ( n = 20), and the healthy control group ( n = 20). Associations between changes in the protein expressions and clinico-pathological parameters were also analyzed in the metastatic castration-resistant prostate cancer group. When comparing BPH and healthy groups with the metastatic castration-resistant prostate cancer group, a reduced expression of integrin-α4 was found in metastatic patients, albeit being statistically insignificant ( P > 0.05). Protein expressions of periostin and fibronectin in the metastatic castration-resistant prostate cancer group were higher than those in the BPH and heathy groups ( P < 0.001). Increased periostin expression in metastatic patients was significantly associated with bone metastasis ( P < 0.05). Elevated periostin and fibronectin levels in metastatic castration-resistant prostate cancer patients may be appropriate targets of therapeutic intervention in the future. Impact statement Prostate cancer is the third most common cancer in the world and the most common cancer among men. Development of metastatic castration-resistant prostate cancer (mCRPC) is a result of the lack of an apoptotic response by the tumor cells and loss of the ability to stick to adjacent cells through epithelial-mesenchymal transition (EMT). The present study analyzes for the first time the expressions of EMT marker proteins - periostin, integrin α4, fibronectin - in mCRPC and in benign prostatic hyperplasia (BPH) with the aim to determine the clinical relevance of changes in these three proteins vis-a-vis the PCa aggressive phenotype. In doing so, it sheds light on the molecular mechanism underlying the disease. We concluded that elevated periostin and fibronectin levels in mCRPC patients may be appropriate targets of therapeutic intervention in the future; hence, adopting methods that target these proteins may help treat prostate cancer effectively.

Extracellular matrix dynamics and functions in the social amoeba Dictyostelium: A critical review

BACKGROUND

The extracellular matrix (ECM) is a dynamic complex of glycoproteins, proteoglycans, carbohydrates, and collagen that serves as an interface between mammalian cells and their extracellular environment. Essential for normal cellular homeostasis, physiology, and events that occur during development, it is also a key functionary in a number of human diseases including cancer. The social amoeba Dictyostelium discoideum secretes an ECM during multicellular development that regulates multicellularity, cell motility, cell differentiation, and morphogenesis, and provides structural support and protective layers to the resulting differentiated cell types. Proteolytic processing within the Dictyostelium ECM leads to specific bioactive factors that regulate cell motility and differentiation.

SCOPE OF REVIEW

Here we review the structure and functions of the Dictyostelium ECM and its role in regulating multicellular development. The questions and challenges that remain and how they can be answered are also discussed.

MAJOR CONCLUSIONS

The Dictyostelium ECM shares many of the features of mammalian and plant ECM, and thus presents an excellent system for studying the structure and function of the ECM.

GENERAL SIGNIFICANCE

As a genetically tractable model organism, Dictyostelium offers the potential to further elucidate ECM functions, and to possibly reveal previously unknown roles for the ECM.

The Management of Diabetic Foot Ulcers with Porcine Small Intestine Submucosa Tri-Layer Matrix: A Randomized Controlled Trial

Objective: This study demonstrates that superior outcomes are possible when diabetic foot ulcers (DFU) are managed with tri-layer porcine small intestine submucosa (SIS).

Approach: Patients with DFU from 11 centers participated in this prospective randomized controlled trial. Qualified subjects were randomized (1:1) to either SIS or standard care (SC) selected at the discretion of the Investigator and followed for 12 weeks or complete ulcer closure.

Results: Eighty-two subjects (41 in each group) were evaluable in the intent-to-treat analysis. Ulcers managed with SIS had a significantly greater proportion closed by 12 weeks than for the Control group (54% vs. 32%, p=0.021) and this proportion was numerically higher at all visits. Time to closure for ulcers achieving closure was 2 weeks earlier for the SIS group than for SC. Median reduction in ulcer area was significantly greater for SIS at each weekly visit (all p values<0.05). Review of reported adverse events found no safety concerns.

Innovation: These data support the use of tri-layer SIS for the effective management of DFU.

Conclusion: In this randomized controlled trial, SIS was found to be associated with more rapid improvement, and a higher likelihood of achieving complete ulcer closure than those ulcers treated with SC.

Immunohistochemical localization of periostin in human gingiva

The periostin is a matricellular protein expressed in collagen-rich tissues including some dental and periodontal tissues where it is regulated by mechanical forces, growth factors and cytokines. Interestingly the expression of this protein has been found modified in different gingival pathologies although the expression of periostin in normal human gingiva was never investigated. Here we used Western blot and double immunofluorescence coupled to laser-confocal microscopy to investigated the occurrence and distribution of periostin in different segments of the human gingival in healthy subjects. By Western blot a protein band with an estimated molecular mass of 94 kDa was observed. Periostin was localized at the epithelial-connective tissue junction, or among the fibers of the periodontal ligament, and never co-localized with cytokeratin or vimentin thus suggesting it is an extracellular protein. These results demonstrate the occurrence of periostin in adult human gingiva; its localization suggests a role in the bidirectional interactions between the connective tissue and the epithelial cells, and therefore in the physiopathological conditions in which these interactions are altered.

The novel secreted factor MIG-18 acts with MIG-17/ADAMTS to control cell migration in Caenorhabditis elegans

The migration of Caenorhabditis elegans gonadal distal tip cells (DTCs) offers an excellent model to study the migration of epithelial tubes in organogenesis. mig-18 mutants cause meandering or wandering migration of DTCs during gonad formation, which is very similar to that observed in animals with mutations in mig-17, which encodes a secreted metalloprotease of the ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family. MIG-18 is a novel secreted protein that is conserved only among nematode species. The mig-17(null) and mig-18 double mutants exhibited phenotypes similar to those in mig-17(null) single mutants. In addition, the mutations in fbl-1/fibulin-1 and let-2/collagen IV that suppress mig-17 mutations also suppressed the mig-18 mutation, suggesting that mig-18 and mig-17 function in a common genetic pathway. The Venus-MIG-18 fusion protein was secreted from muscle cells and localized to the gonadal basement membrane, a tissue distribution reminiscent of that observed for MIG-17. Overexpression of MIG-18 in mig-17 mutants and vice versa partially rescued the relevant DTC migration defects, suggesting that MIG-18 and MIG-17 act cooperatively rather than sequentially. We propose that MIG-18 may be a cofactor of MIG-17/ADAMTS that functions in the regulation of the gonadal basement membrane to achieve proper direction of DTC migration during gonadogenesis.

Periostin cooperates with mutant p53 to mediate invasion through the induction of STAT1 signaling in the esophageal tumor microenvironment

Periostin (POSTN), a matricellular protein, has been reported to be important in supporting tumor cell dissemination. However, the molecular mechanisms underlying POSTN function within the tumor microenvironment are poorly understood. In this study, we observe that the inducible knockdown of POSTN decreases esophageal squamous cell carcinoma (ESCC) tumor growth in vivo and demonstrate that POSTN cooperates with a conformational missense p53 mutation to enhance invasion. Pathway analyses reveal that invasive esophageal cells expressing POSTN and p53(R175H) mutation display activation of signal transducer and activator of transcription 1 (STAT1) target genes, suggesting that the induction of STAT1 and STAT1-related genes could foster a permissive microenvironment that facilitates invasion of esophageal epithelial cells into the extracellular matrix. Genetic knockdown of STAT1 in transformed esophageal epithelial cells underscores the importance of STAT1 in promoting invasion. Furthermore, we find that STAT1 is activated in ESCC xenograft tumors, but this activation is attenuated with inducible knockdown of POSTN in ESCC tumors. Overall, these results highlight the novel molecular mechanisms supporting the capacity of POSTN in mediating tumor invasion during ESCC development and have implications of therapeutic strategies targeting the tumor microenvironment.

Matricellular signal transduction involving calmodulin in the social amoebozoan dictyostelium

The social amoebozoan Dictyostelium discoideum undergoes a developmental sequence wherein an extracellular matrix (ECM) sheath surrounds a group of differentiating cells. This sheath is comprised of proteins and carbohydrates, like the ECM of mammalian tissues. One of the characterized ECM proteins is the cysteine-rich, EGF-like (EGFL) repeat-containing, calmodulin (CaM)-binding protein (CaMBP) CyrA. The first EGFL repeat of CyrA increases the rate of random cell motility and cyclic AMP-mediated chemotaxis. Processing of full-length CyrA (~63 kDa) releases two major EGFL repeat-containing fragments (~45 kDa and ~40 kDa) in an event that is developmentally regulated. Evidence for an EGFL repeat receptor also exists and downstream intracellular signaling pathways involving CaM, Ras, protein kinase A and vinculin B phosphorylation have been characterized. In total, these results identify CyrA as a true matricellular protein comparable in function to tenascin C and other matricellular proteins from mammalian cells. Insight into the regulation and processing of CyrA has also been revealed. CyrA is the first identified extracellular CaMBP in this eukaryotic microbe. In keeping with this, extracellular CaM (extCaM) has been shown to be present in the ECM sheath where it binds to CyrA and inhibits its cleavage to release the 45 kDa and 40 kDa EGFL repeat-containing fragments. The presence of extCaM and its role in regulating a matricellular protein during morphogenesis extends our understanding of CaM-mediated signal transduction in eukaryotes.

Matricellular proteins: priming the tumour microenvironment for cancer development and metastasis

Matricellular proteins have been classified as a family of non-structural matrix proteins capable of modulating a variety of biological processes within the extracellular matrix (ECM). These proteins are expressed dynamically and their cellular functions are highly dependent upon cues from the local environment. Recent studies have shown an increasing appreciation of the key roles these ECM proteins play within the tumour microenvironment. Induced by either tumour cells or tumour stromal components, matricellular proteins initiate downstream signalling events that lead to proliferation, invasion, matrix remodelling and dissemination to pre-metastatic niches in other organs. In this review, we summarise and discuss the current knowledge of the diverse roles these proteins play within the microenvironment that influences tumour progression and potential for future therapies targeting the tumour microenvironment.

A matricellular protein and EGF-like repeat signalling in the social amoebozoan Dictyostelium discoideum

Matricellular proteins interact with the extracellular matrix (ECM) and modulate cellular processes by binding to cell surface receptors and initiating intracellular signal transduction. Their association with the ECM and the ability of some members of this protein family to regulate cell motility have opened up new avenues of research to investigate their functions in normal and diseased cells. In this review, we summarize the research on CyrA, an ECM calmodulin-binding protein in Dictyostelium. CyrA is proteolytically cleaved into smaller EGF-like (EGFL) repeat containing cleavage products during development. The first EGFL repeat of CyrA binds to the cell surface and activates a novel signalling pathway that modulates cell motility in this model organism. The similarity of CyrA to the most well-characterized matricellular proteins in mammals allows it to be designated as the first matricellular protein identified in Dictyostelium.

CyrA, a matricellular protein that modulates cell motility in Dictyostelium discoideum

CyrA, an extracellular matrix (slime sheath), calmodulin (CaM)-binding protein in Dictyostelium discoideum, possesses four tandem EGF-like repeats in its C-terminus and is proteolytically cleaved during asexual development. A previous study reported the expression and localization of CyrA cleavage products CyrA-C45 and CyrA-C40. In this study, an N-terminal antibody was produced that detected the full-length 63kDa protein (CyrA-C63). Western blot analyses showed that the intracellular expression of CyrA-C63 peaked between 12 and 16h of development, consistent with the time that cells are developing into a motile, multicellular slug. CyrA immunolocalization and CyrA-GFP showed that the protein localized to the endoplasmic reticulum, particularly its perinuclear component. CyrA-C63 secretion began shortly after the onset of starvation peaking between 8 and 16h of development. A pharmacological analysis showed that CyrA-C63 secretion was dependent on intracellular Ca(2+) release and active CaM, PI3K, and PLA2. CyrA-C63 bound to CaM both intra- and extracellularly and both proteins were detected in the slime sheath deposited by migrating slugs. In keeping with its purported function, CyrA-GFP over-expression enhanced cAMP-mediated chemotaxis and CyrA-C45 was detected in vinculin B (VinB)-GFP immunoprecipitates, thus providing a link between the increase in chemotaxis and a specific cytoskeletal component. Finally, DdEGFL1-FITC was detected on the membranes of cells capped with concanavalin A suggesting that a receptor exists for this peptide sequence. Together with previous studies, the data presented here suggests that CyrA is a bona fide matricellular protein in D. discoideum.