De novo decorin gene expression suppresses the malignant phenotype in human colon cancer cells

RBM15 Knockdown Impairs the Malignancy of Cervical Cancer by Mediating m6A Modification of Decorin

Cervical cancer (CC) is considered to be the most prevalent female malignancies across the globe and a prime cause of mortality among women. RNA-binding motif protein 15 (RBM15) has been elucidated to participate in tumorigenesis in various cancers by regulating RNA N6-methyladenosine (m6A) methylation. However, its significance and detailed molecular mechanisms remain uncertain in CC. Using CGA database and qRT-PCR, the RBM15 expression was found to be elevated in CC tissues. After performing EdU, wound healing, Transwell migration, and xenograft tumor assays, RBM15 knockdown inhibited the malignant properties of CC cells along with the tumor development of CC cells in vivo. Moreover, qRT-PCR, MeRIP, and western blotting experiments were also confirmed that decorin (DCN) downregulated in CC was a direct substrate of RBM15 m6A methylation, and RBM15 knockdown could enhance DCN expression in CC cells. The anti-tumor effects of RBM15 knockdown could be abolished by DCN silencing. Overall, RBM15 knockdown lowered the tumorigenesis of CC both in vitro and in vivo, and it does so via mediating m6A modification of DCN mRNA in CC cells.

Decorin evokes reversible mitochondrial depolarization in carcinoma and vascular endothelial cells

Decorin, a small leucine-rich proteoglycan with multiple biological functions, is known to evoke autophagy and mitophagy in both endothelial and cancer cells. Here, we investigated the effects of soluble decorin on mitochondrial homeostasis using live cell imaging and ex vivo angiogenic assays. We discovered that decorin triggers mitochondrial depolarization in triple-negative breast carcinoma, HeLa, and endothelial cells. This bioactivity was mediated by the protein core in a time- and dose-dependent manner and was specific for decorin insofar as biglycan, the closest homolog, failed to trigger depolarization. Mechanistically, we found that the bioactivity of decorin to promote depolarization required the MET receptor and its tyrosine kinase. Moreover, two mitochondrial interacting proteins, mitostatin and mitofusin 2, were essential for downstream decorin effects. Finally, we found that decorin relied on the canonical mitochondrial permeability transition pore to trigger tumor cell mitochondrial depolarization. Collectively, our study implicates decorin as a soluble outside-in regulator of mitochondrial dynamics.

Oncosuppressive roles of decorin through regulation of multiple receptors and diverse signaling pathways

Decorin is a stromal-derived prototype member of the small leucine-rich proteoglycan gene family. In addition to its functions as a regulator of collagen fibrillogenesis and TGF-β activity soluble decorin acts as a pan-receptor tyrosine kinase (RTK) inhibitor. Decorin binds to various RTKs including EGFR HER2 HGFR/Met VEGFR2 TLR and IGFR. Although the molecular mechanism for the action of decorin on these receptors is not entirely elucidated overall decorin evokes transient activation of these receptors with suppression of downstream signaling cascades culminating in growth inhibition followed by their physical downregulation via caveosomal internalization and degradation. In the case of Met decorin leads to decreased β-catenin signaling pathway and growth suppression. As most of these RTKs are responsible for providing a growth advantage to cancer cells the result of decorin treatment is oncosuppression. Another decorin-driven mechanism to restrict cancer growth and dissemination is by impeding angiogenesis via vascular endothelial growth factor receptor 2 (VEGFR2) and the concurrent activation of protracted endothelial cell autophagy. In this review we will dissect the multiple roles of decorin in cancer biology and its potential use as a next-generation protein-based adjuvant therapy to combat cancer.

Bone marrow plasma level of decorin may be associated with improved treatment outcomes in a subset of multiple myeloma patients

BACKGROUND/PURPOSE

Decorin is a small leucine-rich proteoglycan rich in extracellular matrix with potential antitumor activity. However, the role of decorin in hematological malignancies remains unclear, especially in the case of multiple myeloma (MM), a bone marrow (BM) stroma-dependent plasma cell neoplasm.

METHODS

We measured decorin levels in BM plasma samples from 270 patients with newly diagnosed MM (NDMM) using enzyme-linked immunosorbent assays.

RESULTS

Patients were divided into high decorin (H-DCN, > 18.99 ng/mL) and low decorin (L-DCN <9.76 ng/mL) groups. Patients in the H-DCN group had more advanced-stage disease, including more osteolysis terms of higher levels of C-terminal telopeptides of type I collagen (0.69 ± 0.55 vs. 0.49 ± 0.36 ng/mL; P = 0.028), than those in the L-DCN group. Decorin levels correlated positively with hepatocyte growth factor (HGF) levels in BM plasma samples from NDMM patients (Pearson correlation coefficient, 0.226; P < 0.001). Patients with low HGF (<0.79 ng/mL) but high decorin levels (≥12.95 ng/mL) had a higher treatment response rate (90.5% vs. 54.5%, respectively; P = 0.015) and improved overall survival (not reached vs. 53 months; P = 0.0148) than those with lower decorin levels (<12.95 ng/mL). Multivariate analysis confirmed that a high decorin level was an independent predictive factor for treatment response and survival in patients with low HGF levels.

CONCLUSION

Our findings suggest that decorin may exert protective effects in this subset of MM patients.

A functional outside-in signaling network of proteoglycans and matrix molecules regulating autophagy

Proteoglycans and selected extracellular matrix constituents are emerging as intrinsic and critical regulators of evolutionarily conversed, intracellular catabolic pathways. Often, these secreted molecules evoke sustained autophagy in a variety of cell types, tissues, and model systems. The unique properties of proteoglycans have ushered in a paradigmatic shift to broaden our understanding of matrix-mediated signaling cascades. The dynamic cellular pathway controlling autophagy is now linked to an equally dynamic and fluid signaling network embedded in a complex meshwork of matrix molecules. A rapidly emerging field of research encompasses multiple matrix-derived candidates, representing a menagerie of soluble matrix constituents including decorin, biglycan, endorepellin, endostatin, collagen VI and plasminogen kringle 5. These matrix constituents are pro-autophagic and simultaneously anti-angiogenic. In contrast, perlecan, laminin α2 chain, and lumican have anti-autophagic functions. Mechanistically, each matrix constituent linked to intracellular catabolic events engages a specific cell surface receptor that often converges on a common core of the autophagic machinery including AMPK, Peg3 and Beclin 1. We consider this matrix-evoked autophagy as non-canonical given that it occurs in an allosteric manner and is independent of nutrient availability or prevailing bioenergetics control. We propose that matrix-regulated autophagy is an important outside-in signaling mechanism for proper tissue homeostasis that could be therapeutically leveraged to combat a variety of diseases.

Decorin deficiency promotes epithelial-mesenchymal transition and colon cancer metastasis

The tumor microenvironment encompasses a complex cellular network that includes cancer-associated fibroblasts, inflammatory cells, neo-vessels, and an extracellular matrix enriched in angiogenic growth factors. Decorin is one of the main components of the tumor stroma, but it is not expressed by cancer cells. Lack of this proteoglycan correlates with down-regulation of E-cadherin and induction of β-catenin signaling. In this study, we investigated the role of a decorin-deficient tumor microenvironment in colon carcinoma progression and metastasis. We utilized an established model of colitis-associated cancer by administering Azoxymethane/Dextran sodium sulfate to adult wild-type and Dcn^-/- mice. We discovered that after 12 weeks, all the animals developed intestinal tumors independently of their genotype. However, the number of intestinal neoplasms was significantly higher in the Dcn^-/- microenvironment vis-à-vis wild-type mice. Mechanistically, we found that under unchallenged basal conditions, the intestinal epithelium of the Dcn^-/- mice showed a significant increase in the protein levels of epithelial-mesenchymal transition associated factors including Snail, Slug, Twist, and MMP2. In comparison, in the colitis-associated cancer evoked in the Dcn^-/- mice, we found that intercellular adhesion molecule 1 (ICAM-1) was also significantly increased, in parallel with epithelial-mesenchymal transition signaling pathway-related factors. Furthermore, a combined Celecoxib/decorin treatment revealed a promising therapeutic efficacy in treating human colorectal cancer cells, in decorin-deficient animals. Collectively, our results shed light on colorectal cancer progression and provide a protein-based therapy, i.e., treatment using recombinant decorin, to target the tumor microenvironment.

Decorin in the Tumor Microenvironment

The tumor microenvironment plays a determining role in cancer development through a plethora of interactions between the extracellular matrix and tumor cells. Decorin is a prototype member of the SLRP family found in a variety of tissues and is expressed in the stroma of various forms of cancer. Decorin has gained recognition for its essential roles in inflammation, fibrotic disorders, and cancer, and due to its antitumor properties, it has been proposed to act as a "guardian from the matrix." Initially identified as a natural inhibitor of transforming growth factor-β, soluble decorin is emerging as a pan-RTK inhibitor targeting a multitude of RTKs, including EGFR, Met, IGF-IR, VEGFR2, and PDGFR. Besides initiating signaling, decorin/RTK interaction can induce caveosomal internalization and receptor degradation. Decorin also triggers cell cycle arrest and apoptosis and evokes antimetastatic and antiangiogenic processes. In addition, as a novel regulatory mechanism, decorin was shown to induce conserved catabolic processes, such as endothelial cell autophagy and tumor cell mitophagy. Therefore, decorin is a promising candidate for combatting cancer, especially the cancer types heavily dependent on RTK signaling.

Decorin expression is associated with predictive diffusion MR phenotypes of anti-VEGF efficacy in glioblastoma

Previous data suggest that apparent diffusion coefficient (ADC) imaging phenotypes predict survival response to anti-VEGF monotherapy in glioblastoma. However, the mechanism by which imaging may predict clinical response is unknown. We hypothesize that decorin (DCN), a proteoglycan implicated in the modulation of the extracellular microenvironment and sequestration of pro-angiogenic signaling, may connect ADC phenotypes to survival benefit to anti-VEGF therapy. Patients undergoing resection for glioblastoma as well as patients included in The Cancer Genome Atlas (TCGA) and IVY Glioblastoma Atlas Project (IVY GAP) databases had pre-operative imaging analyzed to calculate pre-operative ADC_L values, the average ADC in the lower distribution using a double Gaussian mixed model. ADC_L values were correlated to available RNA expression from these databases as well as from RNA sequencing from patient derived mouse orthotopic xenograft samples. Targeted biopsies were selected based on ADC values and prospectively collected during resection. Surgical specimens were used to evaluate for DCN RNA and protein expression by ADC value. The IVY Glioblastoma Atlas Project Database was used to evaluate DCN localization and relationship with VEGF pathway via in situ hybridization maps and RNA sequencing data. In a cohort of 35 patients with pre-operative ADC imaging and surgical specimens, DCN RNA expression levels were significantly larger in high ADC_L tumors (41.6 vs. 1.5; P = 0.0081). In a cohort of 17 patients with prospectively targeted biopsies there was a positive linear correlation between ADC_L levels and DCN protein expression between tumors (Pearson R² = 0.3977; P = 0.0066) and when evaluating different targets within the same tumor (Pearson R² = 0.3068; P = 0.0139). In situ hybridization data localized DCN expression to areas of microvascular proliferation and immunohistochemical studies localized DCN protein expression to the tunica adventitia of blood vessels within the tumor. DCN expression positively correlated with VEGFR1 & 2 expression and localized to similar areas of tumor. Increased ADC_L on diffusion MR imaging is associated with high DCN expression as well as increased survival with anti-VEGF therapy in glioblastoma. DCN may play an important role linking the imaging features on diffusion MR and anti-VEGF treatment efficacy. DCN may serve as a target for further investigation and modulation of anti-angiogenic therapy in GBM.

Chrysophanol exhibits inhibitory activities against colorectal cancer by targeting decorin

Colorectal cancer (CRC) is a common human malignancy that accounts for 600,000 deaths annually worldwide. Chrysophanol, a naturally occurring anthraquinone compound, exhibits anti-neoplastic effects in various cancer cells. The aim of this study was to explore the biological effects of chrysophanol on CRC cells, and determine the underlying mechanism. Chrysophanol inhibited proliferation of and promoted apoptosis in CRC cells by activating the intrinsic mitochondrial apoptotic pathway. In addition, chrysophanol also suppressed tumor growth in vivo and increased the percentage of apoptotic cells in tumor xenografts, without general toxicity. Proteomic iTRAQ analysis revealed decorin (DCN) as the major target of chrysophanol. DCN was upregulated in the tumor tissues following chrysophanol treatment, and ectopic DCN expression markedly augmented the pro-apoptotic effects of chrysophanol in CRC cells. In contrast, DCN knockdown significantly abrogated chrysophanol-induced apoptosis in CRC cells. Taken together, chrysophanol exerts anti-neoplastic effects in vitro and in vivo in CRC cells by modulating DCN, there by highlighting its therapeutic potential in CRC.

The Role of Stroma in Ovarian Cancer

Background: Ovarian cancer is one of the gynecological malignancies responsible for thousands of deaths in women worldwide. Malignant solid tumors are formed by malignant cells and stroma that influence each other, where different types of cells in the stromal environment can be recruited by malignant cells to promote tumor growth and facilitate metastasis. The chronic inflammatory response is increasingly accepted in its relation to the pathophysiology of the onset and development of tumors, sustained cell proliferation in an environment rich in inflammatory cells, growth factors, activated stroma and DNA damage agents may increase the risk to develop a neoplasm.Methods: A search for the following keywords was performed in the PubMed database; "Ovarian cancer", "stroma", "tumor-associated macrophages", "cancer-associated fibroblasts", "cytokines", "angiogenesis", "epithelial-mesenchymal transition", and "extracellular matrix".Results: The articles identified were published in English between 1971 and 2018. A total of 154 articles were selected for further analysis. Conclusion: We consider ovarian cancer as a heterogeneous disease, not only in the sense that different histological or molecular subtypes may be behind the same clinical result, but also that multiple cell types besides cancer cells, like other non-cellular components, need to be mobilized and coordinated to support tumor survival, growth, invasion and progression.

Tumor-specific inhibitory action of decorin on different hepatoma cell lines

BACKGROUND

In spite of therapeutic approaches, liver cancer is still one of the deadliest type of tumor in which tumor microenvironment may play an active role in the outcome of the disease. Decorin, a small leucine-rich proteoglycan is not only responsible for assembly and maintenance of the integrity of the extracellular matrix, but a natural inhibitor of cell surface receptors, thus it exerts antitumorigenic effects. Here we addressed the question whether this effect of decorin is independent of the tumor phenotypes including differentiation, proliferation and invasion.

METHOD

Four hepatoma cell lines HepG2, Hep3B, HuH7 and HLE, possessing different molecular backgrounds, were selected to investigate. After proliferation tests, pRTK arrays, WB analyses, and immunofluorescent examinations were performed on decorin treated and control cells for comparison.

RESULTS

Significant growth inhibitory potential of decorin on three out of four hepatoma cell lines was proven, however the mode of its action was different. Induction of p21^WAF1/CIP1, increased inactivation of c-myc and β-catenin, and decrease of EGFR, GSK3β and ERK1/2 phosphorylation levels were observed in HepG2 cells, pathways already well-described in literature. However, in the p53 deficient Hep3B and HuH7, InsR and IGF-1R were the main receptors transmitting signals. In harmony with its receptor status, Hep3B cells displayed high level of activated AKT. As the cell line is retinoblastoma mutant, ATR/Chk1/Wee1 system might hinder the cell cycle in G2/M phase via phosphorylation of CDK1. In Huh7 cells, all RTKs were inhibited by decorin followed by downregulation of AKT. Furthermore, HuH7 cell line responded with concentration-dependent ERK activation and increased phospho-c-myc level. Decorin had only a non-significant effect on the proliferation rate of HLE cell line. However, it responded with a significant decrease of pAKT, c-myc and β-catenin activity. In this special cell line, the inhibition of TGFβ may be the first step of the protective effect of decorin.

CONCLUSIONS

Based on our results decorin may be a candidate therapeutic agent in the battle against liver cancer, but several questions need to be answered. It is certain that decorin is capable to exert its suppressor effect in hepatoma cells without respect to their phenotype and molecular background.

Association of matrix metalloproteinase-9 and decorin expression with the infiltration of cervical cancer

Matrix metalloproteinase-9 (MMP9) has been recognized to be an important factor in cancer invasion and metastasis. In contrast, decorin has been revealed to inhibit primary tumor development. The aim of the present study was to investigate the function of MMP9 and decorin in cervical cancer. Three experiments were performed to analyze the function of MMP9 and decorin in the invasion of cervical cancer by: i) Analyzing the expression of MMP9 and decorin by immunohistochemistry in 100 cervical specimens; ii) determining the concentration of decorin by an enzyme-linked immunosorbent assay (ELISA) using the human squamous cervical cancer cell line CaSki and human endometrial stromal cell line CRL4003 and iii) evaluating the invasion ability of CaSki cells in a cervical invasion model by an invasion assay. Immunohistochemistry revealed that MMP9 was overexpressed in microinvasive carcinoma (100.0%) but was less strongly expressed in normal or pre-malignant squamous epithelium (0-41.9%). In contrast, the activity of decorin in stroma adjacent to neoplastic cells was lower in microinvasive carcinoma (9.1%) compared with in normal or pre-malignant lesions (74.2-100.0%). An ELISA revealed that MMP9 released from CaSki cells resolved the decorin released from CRL4003 cells. An invasion assay demonstrated that the invasive ability of CaSki cells was suppressed by an MMP inhibitor, and decorin was released from CRL4003 cells. These data suggested that decorin prevented the invasion of malignant cells in uterine cervical cancer; however, MMP9 promotes cell invasion by destroying decorin.

The evolving relationship of wound healing and tumor stroma

The stroma in solid tumors contains a variety of cellular phenotypes and signaling pathways associated with wound healing, leading to the concept that a tumor behaves as a wound that does not heal. Similarities between tumors and healing wounds include fibroblast recruitment and activation, extracellular matrix (ECM) component deposition, infiltration of immune cells, neovascularization, and cellular lineage plasticity. However, unlike a wound that heals, the edges of a tumor are constantly expanding. Cell migration occurs both inward and outward as the tumor proliferates and invades adjacent tissues, often disregarding organ boundaries. The focus of our review is cancer associated fibroblast (CAF) cellular heterogeneity and plasticity and the acellular matrix components that accompany these cells. We explore how similarities and differences between healing wounds and tumor stroma continue to evolve as research progresses, shedding light on possible therapeutic targets that can result in innovative stromal-based treatments for cancer.

Endoplasmic reticulum (ER) stress triggers Hax1-dependent mitochondrial apoptotic events in cardiac cells

Cardiomyocyte apoptosis is a major process in pathogenesis of a number of heart diseases, including ischemic heart diseases and cardiac failure. Ensuring survival of cardiac cells by blocking apoptotic events is an important strategy to improve cardiac function. Although the role of ER disruption in inducing apoptosis has been demonstrated, we do not yet fully understand how it influences the mitochondrial apoptotic machinery in cardiac cell models. Recent investigations have provided evidences that the prosurvival protein HCLS1-associated protein X-1 (Hax1) protein is intimately associated with the pathogenesis of heart disease, mitochondrial biology, and protection from apoptotic cell death. To study the role of Hax1 upon ER stress induction, Hax1 was overexpressed in cardiac cells subjected to ER stress, and cell death parameters as well as mitochondrial alterations were examined. Our results demonstrated that the Hax1 is significantly downregulated in cardiac cells upon ER stress induction. Moreover, overexpression of Hax1 protected from apoptotic events triggered by Tunicamycin-induced ER stress. Upon treatment with Tunicamycin, Hax1 protected from mitochondrial fission, downregulation of mitofusins 1 and 2 (MFN1 and MFN2), loss of mitochondrial membrane potential (∆Ψm), production of reactive oxygen species (ROS) and apoptotic cell death. Taken together, our results suggest that Hax1 inhibits ER stress-induced apoptosis at both the pre- and post-mitochondrial levels. These findings may offer an opportunity to develop new agents that inhibit cell death in the diseased heart.

Biglycan-mediated upregulation of MHC class I expression in HER-2/neu-transformed cells

The extracellular matrix protein biglycan (BGN) has oncogenic or tumor suppressive potential depending on the cellular origin. HER-2/neu overexpression in murine fibroblasts and human model systems is inversely correlated with BGN expression. Upon its restoration BGN^high HER-2/neu⁺ fibroblasts were less tumorigenic in immune competent mice when compared to BGN^low/neg HER-2/neu⁺ cells, which was associated with enhanced immune cell responses and higher frequencies of immune effector cells in tumors and peripheral blood. The increased immunogenicity of BGN^high HER-2/neu⁺ fibroblasts appears to be due to upregulated MHC class I surface antigens and reduced expression levels of transforming growth factor (TGF)-β isoforms and the TGF-β receptor 1 suggesting a link between BGN, TGF-β pathway and HER-2/neu-mediated downregulation of MHC class I antigens. Treatment of BGN^low/neg HER-2/neu⁺ cells with recombinant BGN or an inhibitor of TGF-β enhanced MHC class I surface antigens in BGN^low/neg HER-2/neu-overexpressing murine fibroblasts, which was mediated by a transcriptional upregulation of major MHC class I antigen processing components. Furthermore, BGN expression in HER-2/neu⁺ cells was accompanied by an increased expression of the proteoglycan decorin (DCN). Since recombinant DCN also elevated MHC class I surface expression in BGN^low/neg HER-2/neu⁺ cells, both proteoglycans might act synergistically. This was in accordance with in silico analyses of mRNA data obtained from The Cancer Genome Atlas (TCGA) dataset available for breast cancer (BC) patients. Thus, our data provide for the first time evidence that proteoglycan signatures are modulated by HER-2/neu and linked to MHC class I-mediated immune escape associated with an altered TGF-β pathway.

Decorin is a devouring proteoglycan: Remodeling of intracellular catabolism via autophagy and mitophagy

Autophagy, a fundamental and evolutionarily-conserved eukaryotic pathway, coordinates a complex balancing act for achieving both nutrient and energetic requirements for proper cellular function and homeostasis. We have discovered that soluble proteoglycans evoke autophagy in endothelial cells and mitophagy in breast carcinoma cells by directly interacting with receptor tyrosine kinases, including VEGF receptor 2 and Met. Under these circumstances, autophagic regulation is considered "non-canonical" and is epitomized by the bioactivity of the small leucine-rich proteoglycan, decorin. Soluble matrix-derived cues being transduced downstream of receptor engagement converge upon a newly-discovered nexus of autophagic machinery consisting of Peg3 for endothelial cell autophagy and mitostatin for tumor cell mitophagy. In this thematic mini-review, we will provide an overview of decorin-mediated autophagy and mitophagy and propose that regulating intracellular catabolism is the underlying molecular basis for the versatility of decorin as a potent oncosuppressive agent.

EphA2 signaling is impacted by carcinoembryonic antigen cell adhesion molecule 1-L expression in colorectal cancer liver metastasis in a cell context-dependent manner

We have shown that carcinoembryonic antigen cell adhesion molecule 1 long isoform (CEACAM1-L) expression in MC38 metastatic colorectal cancer (CRC) cells results in liver metastasis inhibition via CCL2 and STAT3 signaling. But other molecular mechanisms orchestrating CEACAM1-L-mediated metastasis inhibition remain to be defined. We screened a panel of mouse and human CRC cells and evaluated their metastatic outcome after CEACAM1 overexpression or downregulation. An unbiased transcript profiling and a phospho-receptor tyrosine kinase screen comparing MC38 CEACAM1-L-expressing and non-expressing (CT) CRC cells revealed reduced ephrin type-A receptor 2 (EPHA2) expression and activity. An EPHA2-specific inhibitor reduced EPHA2 downstream signaling in CT cells similar to that in CEACAM1-L cells with decreased proliferation and migration. Human CRC patients exhibiting high CEACAM1 in combination with low EPHA2 expression benefited from longer time to first recurrence/metastasis compared to those with high EPHA2 expression. With the added interaction of CEACAM6, we denoted that CEACAM1 high- and EPHA2 low-expressing patient samples with lower CEACAM6 expression also exhibited a longer time to first recurrence/metastasis. In HT29 human CRC cells, down-regulation of CEACAM1 along with CEA and CEACAM6 up-regulation led to higher metastatic burden. Overall, CEACAM1-L expression in poorly differentiated CRC can inhibit liver metastasis through cell context-dependent EPHA2-mediated signaling. However, CEACAM1’s role should be considered in the presence of other CEACAM family members.

Altered expression of small leucine-rich proteoglycans (Decorin, Biglycan and Lumican): Plausible diagnostic marker in urothelial carcinoma of bladder

Small leucine-rich proteoglycans are components of extracellular matrix that regulates neoplastic transformation. Among small leucine rich proteoglycans, Decorin, Biglycan and Lumican are most commonly implicated markers, and their expression is well studied in various malignancies. In this novel study, we have collectively evaluated expression of these three molecules in urothelial carcinoma of bladder. Thirty patients of confirmed untreated bladder cancer, 30 healthy controls for blood and 30 controls for adjacent non-tumour tissue were enrolled. Blood was collected from all subjects and tumour/adjacent normal tissue was obtained from the patients. Circulatory levels were estimated by enzyme-linked immunosorbent assay, relative messenger RNA expression by quantitative polymerase chain reaction and protein expression by immunohistochemistry and western-blotting. Circulatory levels of Biglycan (p = 0.0038) and Lumican (p < 0.0001) were significantly elevated, and that of Decorin (p < 0.0001) was significantly reduced in patients as compared with controls. Protein expression by immunohistochemistry and western-blotting showed elevated expression of Lumican and Biglycan and lower expression of Decorin in urothelial carcinoma of bladder. Quantitative polymerase chain reaction for messenger RNA expression from tissue specimens revealed significantly higher expression of Biglycan (p = 0.0008) and Lumican (p = 0.01) and lower expression of Decorin (p < 0.0001) in urothelial carcinoma of bladder. Out of all molecules receiver operating characteristic curve showed that the 0.207 ng/ml cut-off of serum Lumican provided optimum sensitivity (90.0%) and specificity (90.0%). Significant alteration of matrix small leucine-rich proteoglycans in urothelial carcinoma of bladder was observed. Higher expression of Lumican in Bladder cancer patients with the cut-off value of highest optimum sensitivity and specificity shows its importance as a potential non-invasive marker for early detection of UBC following further validation in large patient cohort.

Negative Correlation between miR-200c and Decorin Plays an Important Role in the Pathogenesis of Colorectal Carcinoma

Aim. To demonstrate the regulatory role of miRNA in colorectal carcinoma (CRC) and reveal the transcript markers that may be associated with CRC clinical outcomes. Method. Herein, we analyzed both mRNA and miRNA gene expression profiles of 255 CRC tumor samples from The Cancer Genome Atlas project to reveal the regulatory association between miRNA and mRNA. Also, the potential role of gene coexpression network in CRC has been explored. Results. The negative correlation between miR-200c and DCN (Decorin) was calculated in CRC, indicating that DCN could be a potential target of miR-200c. Clinical features indicated that colon polyp history and overall survival were significantly related to the expression level of miR-200c. Three coexpression networks have been constructed, and genes involved in the networks are related to cell cycle, NOTCH, and mTOR signaling pathways. Conclusion. Our result provides a new insight into cancer related mRNA coexpression network in CRC research.

Highly heterogeneous genomic landscape of uterine leiomyomas by whole exome sequencing and genome-wide arrays

OBJECTIVE

To determine the genomic signatures of human uterine leiomyomas and prevalence of MED12 mutations in human uterine leiomyosarcomas.

DESIGN

Retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

This study included a set of 16 fresh frozen leiomyoma and corresponding unaffected myometrium specimens as well as 153 leiomyosarcomas collected from women diagnosed with uterine leiomyomas or leiomyosarcomas who underwent clinically indicated abdominal hysterectomy.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Whole exome sequencing and high-resolution X-chromosome and whole genome single nucleotide polymorphism microarray analyses were performed on leiomyoma samples negative for the known MED12 mutations and compared with their corresponding myometrium. Leiomyosarcoma specimens were examined for exon 2 MED12 mutations to evaluate the frequency of MED12 mutated leiomyosarcomas.

RESULT(S)

Our results indicate remarkable genomic heterogeneity of leiomyoma lesions. MED12-negative leiomyomas contain copy number alterations involving the Mediator complex subunits such as MED8, MED18, CDK8, and long intergenic nonprotein coding RNA340 (CASC15), which may affect the Mediator architecture and/or its transcriptional activity. We also identified mutations in a number of genes that were implicated in leiomyomagenesis such as COL4A6, DCN, and AHR, as well as novel genes: NRG1, ADAM18, HUWE1, FBXW4, FBXL13, and CAPRIN1.

CONCLUSION(S)

Mutations in genes implicated in cell-to-cell interactions and remodeling of the extracellular matrix and genomic aberrations involving genes coding for the Mediator complex subunits were identified in uterine leiomyomas. Additionally, we discovered that ∼4.6% of leiomyosarcomas harbored MED12 exon 2 mutations, but the relevance of this association with molecular pathogenesis of leiomyosarcoma remains unknown.

Molecular cloning, expression analysis, and function of decorin in goat ovarian granulosa cells

Decorin (DCN), a component of the extracellular matrix (ECM), participates in ECM assembly and influences cell proliferation and apoptosis in many mammalian tissues and cells. However, expression and function of DCN in the ovary remain unclear. This study cloned the full-length cDNA of goat DCN obtained from the ovary of an adult goat. Sequence analysis revealed that the putative DCN protein shared a highly conserved amino acid sequence with known mammalian homologs. The tissue distribution of DCN mRNA expression was evaluated by real-time PCR, and the results showed that DCN was widely expressed in the tissues of adult goat. Immunohistochemistry results suggested that DCN protein existed in the granulosa cells and oocytes from all types of follicles and theca cells of antral follicles. Moreover, hCG-induced DCN mRNA expression was significantly reduced by the inhibitors of protein kinase A, PI3K, or p38 kinase (P < 0.05), which are key mediators involved in hCG-induced DCN expression. Overexpression of DCN significantly increased apoptosis and blocked cell cycle progression in cultured granulosa cells (P < 0.05). Western blot analysis also showed that overexpression of DCN upregulated the expression levels of p21 protein (P < 0.05), whereas no effects were observed on the expression of Bax and Bcl-2 and on Bcl-2/Bax ratio (P > 0.05). These findings suggested that DCN regulates the apoptosis and cell cycle of granulosa cells.

Decorin as a multivalent therapeutic agent against cancer

Decorin is a prototypical small leucine-rich proteoglycan that epitomizes the multifunctional nature of this critical gene family. Soluble decorin engages multiple receptor tyrosine kinases within the target-rich environment of the tumor stroma and tumor parenchyma. Upon receptor binding, decorin initiates signaling pathways within endothelial cells downstream of VEGFR2 that ultimately culminate in a Peg3/Beclin 1/LC3-dependent autophagic program. Concomitant with autophagic induction, decorin blunts capillary morphogenesis and endothelial cell migration, thereby significantly compromising tumor angiogenesis. In parallel within the tumor proper, decorin binds multiple RTKs with high affinity, including Met, for a multitude of oncosuppressive functions including growth inhibition, tumor cell mitophagy, and angiostasis. Decorin is also pro-inflammatory by modulating macrophage function and cytokine secretion. Decorin suppresses tumorigenic growth, angiogenesis, and prevents metastatic lesions in a variety of in vitro and in vivo tumor models. Therefore, decorin would be an ideal therapeutic candidate for combating solid malignancies.

Matricellular proteins as regulators of cancer metastasis to bone

Metastasis is the major cause of death in cancer patients, and a frequent site of metastasis for many cancers is the bone marrow. Therefore, understanding the mechanisms underlying the metastatic process is necessary for future prevention and treatment. The tumor microenvironment is now known to play a role in the metastatic cascade, both at the primary tumor and in metastatic sites, and includes both cellular and non-cellular components. The extracellular matrix (ECM) provides structural support and signaling cues to cells. One particular group of molecules associated with the ECM, known as matricellular proteins, modulate multiple aspects of tumor biology, including growth, migration, invasion, angiogenesis and metastasis. These proteins are also important for normal function in the bone by regulating bone formation and bone resorption. Recent studies have described a link between some of these proteins and metastasis of various tumors to the bone. The aim of this review is to summarize what is currently known about matricellular protein influence on bone metastasis. Particular attention to the contribution of both tumor cells and non-malignant cells in the bone has been given.

Decorin-Mediated Inhibition of Human Trophoblast Cells Proliferation, Migration, and Invasion and Promotion of Apoptosis In Vitro

Preeclampsia (PE) is a unique complication of pregnancy, the pathogenesis of which has been generally accepted to be associated with the dysfunctions of extravillous trophoblast (EVT) including proliferation, apoptosis, and migration and invasion. Decorin (DCN) has been proved to be a decidua-derived TGF-binding proteoglycan, which negatively regulates proliferation, migration, and invasiveness of human extravillous trophoblast cells. In this study, we identified a higher expression level of decorin in severe PE placentas by both real-time reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). And an inhibitory effect of decorin on proliferation, migration, and invasion and an enhanced effect on apoptosis in trophoblast cells HTR-8/SVneo and JEG-3 were validated in vitro. Also the modulations of decorin on trophoblast cells' metastasis and invasion functions were detected through regulating the matrix metalloproteinases (MMP2 and MMP9). Thus, we suggested that the contribution of decorin to the modulation of trophoblast cells might have implications for the pathogenesis of preeclampsia.

Decorin in Human Colon Cancer: Localization In Vivo and Effect on Cancer Cell Behavior In Vitro

Decorin is generally recognized as a tumor suppressing molecule. Nevertheless, although decorin has been shown to be differentially expressed in malignant tissues, it has often remained unclear whether, in addition to non-malignant stromal cells, cancer cells also express it. Here, we first used two publicly available databases to analyze the current information about decorin expression and immunoreactivity in normal and malignant human colorectal tissue samples. The analyses demonstrated that decorin expression and immunoreactivity may vary in cancer cells of human colorectal tissues. Therefore, we next examined decorin expression in normal, premalignant and malignant human colorectal tissues in more detail using both in situ hybridization and immunohistochemistry for decorin. Our results invariably demonstrate that malignant cells within human colorectal cancer tissues are devoid of both decorin mRNA and immunoreactivity. Identical results were obtained for cells of neuroendocrine tumors of human colon. Using RT-qPCR, we showed that human colon cancer cell lines are also decorin negative, in accordance with the above in vivo results. Finally, we demonstrate that decorin transduction of human colon cancer cell lines causes a significant reduction in their colony forming capability. Thus, strategies to develop decorin-based adjuvant therapies for human colorectal malignancies are highly rational.

Proteoglycan form and function: A comprehensive nomenclature of proteoglycans

We provide a comprehensive classification of the proteoglycan gene families and respective protein cores. This updated nomenclature is based on three criteria: Cellular and subcellular location, overall gene/protein homology, and the utilization of specific protein modules within their respective protein cores. These three signatures were utilized to design four major classes of proteoglycans with distinct forms and functions: the intracellular, cell-surface, pericellular and extracellular proteoglycans. The proposed nomenclature encompasses forty-three distinct proteoglycan-encoding genes and many alternatively-spliced variants. The biological functions of these four proteoglycan families are critically assessed in development, cancer and angiogenesis, and in various acquired and genetic diseases where their expression is aberrant.

Decorin induced by progesterone plays a crucial role in suppressing endometriosis

Dienogest, a synthetic progestin, has been shown to be effective against endometriosis, although it is still unclear as to how it affects the ectopic endometrial cells. Decorin has been shown to be a powerful endogenous tumor repressor acting in a paracrine fashion to limit tumor growth. Our objectives were to examine the direct effects of progesterone and dienogest on the in vitro proliferation of the human ectopic endometrial epithelial and stromal cell lines, and evaluate as to how decorin contributes to this effect. We also examined DCN mRNA expression in 50 endometriosis patients. The growth of both cell lines was inhibited in a dose-dependent manner by both decorin and dienogest. Using a chromatin immunoprecipitation assay, it was noted that progesterone and dienogest directly induced the binding of the decorin promoter in the EMOsis cc/TERT cells (immortalized human ovarian epithelial cells) and CRL-4003 cells (immortalized human endometrial stromal cells). Progesterone and dienogest also led to significant induced cell cycle arrest via decorin by promoting production of p21 in both cell lines in a dose-dependent manner. Decorin also suppressed the expression of MET in both cell lines. We confirmed that DCN mRNA expression in patients treated with dienogest was higher than that in the control group. In conclusion, decorin induced by dienogest appears to play a crucial role in suppressing endometriosis by exerting anti-proliferative effects and inducing cell cycle arrest via the production of p21 human ectopic endometrial cells and eutopic endometrial stromal cells.

Stromal reengineering to treat pancreas cancer

Pancreatic ductal adenocarcinoma co-opts multiple cellular and extracellular mechanisms to create a complex cancer organ with an unusual proclivity for metastasis and resistance to therapy. Cell-autonomous events are essential for the initiation and maintenance of pancreatic ductal adenocarcinoma, but recent studies have implicated critical non-cell autonomous processes within the robust desmoplastic stroma that promote disease pathogenesis and resistance. Thus, non-malignant cells and associated factors are culprits in tumor growth, immunosuppression and invasion. However, even this increasing awareness of non-cell autonomous contributions to disease progression is tempered by the conflicting roles stromal elements can play. A greater understanding of stromal complexity and complicity has been aided in part by studies in highly faithful genetically engineered mouse models of pancreatic ductal adenocarcinoma. Insights gleaned from such studies are spurring the development of therapies designed to reengineer the pancreas cancer stroma and render it permissive to agents targeting cell-autonomous events or to reinstate immunosurveillance. Integrating conventional and immunological treatments in the context of stromal targeting may provide the key to a durable clinical impact on this formidable disease.

Decorin-mediated inhibition of cholangiocarcinoma cell growth and migration and promotion of apoptosis are associated with E-cadherin in vitro

Emerging evidences have shown that decorin expression is significantly reduced in many cancer tissues and cancer cells. However, its biological role and clinical significance in cholangiocarcinoma development and progression are unknown. In this study, immunohistochemistry was conducted to investigate the expression of decorin in cholangiocarcinomas. The results showed that decorin levels markedly decreased in 44 cholangiocarcinoma tissues compared to 40 adjacent normal tissues. The analysis between decorin expression and clinicopathological characteristics in cholangiocarcinoma patients showed that patients with low levels of decorin expression had a relatively poor prognosis. Moreover, recombinant human decorin treatment and overexpression of decorin in cholangiocarcinoma cells could inhibit cell proliferation, migration, and invasion and promote apoptosis. Furthermore, the E-cadherin expression significantly increased after decorin overexpression or use of recombinant human decorin in cholangiocarcinoma cells. Our findings indicated that downregulation of decorin may be identified as a poor prognostic biomarker in cholangiocarcinomas. Also, decorin-mediated inhibition of cholangiocarcinoma cell growth, migration, and invasion and promotion of cell apoptosis might be through regulation of the expression of E-cadherin in vitro.

Identification of stromal differentially expressed proteins in the colon carcinoma by quantitative proteomics

Tumor microenvironment plays very important roles in the carcinogenesis. A variety of stromal cells in the microenvironment have been modified to support the unique needs of the malignant state. This study was to discover stromal differentially expressed proteins (DEPs) that were involved in colon carcinoma carcinogenesis. Laser capture microdissection (LCM) was captured and isolated the stromal cells from colon adenocarcinoma (CAC) and non-neoplastic colon mucosa (NNCM) tissues, respectively. Seventy DEPs were identified between the pooled LCM-enriched CAC and NNCM stroma samples by iTRAQ-based quantitative proteomics. Gene Ontology (GO) relationship analysis revealed that DEPs were hierarchically grouped into 10 clusters, and were involved in multiple biological functions that were altered during carcinogenesis, including extracellular matrix organization, cytoskeleton, transport, metabolism, inflammatory response, protein polymerization, and cell motility. Pathway network analysis revealed 6 networks and 56 network eligible proteins with Ingenuity pathway analysis. Four significant networks functioned in digestive system development and its function, inflammatory disease, and developmental disorder. Eight DEPs (DCN, FN1, PKM2, HSP90B1, S100A9, MYH9, TUBB, and YWHAZ) were validated by Western blotting, and four DEPs (DCN, FN1, PKM2, and HSP90B1) were validated by immunohistochemical analysis. It is the first report of stromal DEPs between CAC and NNCM tissues. It will be helpful to recognize the roles of stromas in the colon carcinoma microenvironment, and improve the understanding of carcinogenesis in colon carcinoma. The present data suggest that DCN, FN1, PKM2, HSP90B1, S100A9, MYH9, TUBB, and YWHAZ might be the potential targets for colon cancer prevention and therapy.

Decorin interferes with platelet-derived growth factor receptor signaling in experimental hepatocarcinogenesis

Decorin, a secreted small leucine-rich proteoglycan, acts as a tumor repressor in a variety of cancers, mainly by blocking the action of several receptor tyrosine kinases such as the receptors for hepatocyte, epidermal and insulin-like growth factors. In the present study we investigated the effects of decorin in an experimental model of thioacetamide-induced hepatocarcinogenesis and its potential role in modulating the signaling of platelet-derived growth factor receptor-α (PDGFRα). Genetic ablation of decorin in mice led to enhanced tumor prevalence and a higher tumor count compared with wild-type mice. These findings correlated with decreased levels of the cyclin-dependent kinase inhibitor p21(Waf1/Cip1) and concurrent activation (phosphorylation) of PDGFRα in the hepatocellular carcinomas generated in the decorin-null vis-à-vis wild-type mice. Notably, in normal liver PDGFRα localized primarily to the membrane of nonparenchymal cells, whereas in the malignant counterpart PDGFRα was expressed by the malignant cells at their cell surfaces. This process was facilitated by a genetic background lacking endogenous decorin. Double immunostaining of the proteoglycan and the receptor revealed only minor colocalization, leading to the hypothesis that decorin would bind to the natural ligand PDGF rather than to the receptor itself. Indeed, we found, using purified proteins and immune-blot assays, that decorin binds to PDGF. Collectively, our findings support the idea that decorin acts as a secreted tumor repressor during hepatocarcinogenesis by hindering the action of another receptor tyrosine kinase, such as the PDGFRα, and could be a novel therapeutic agent in the battle against liver cancer.

Dichotomy of decorin activity on the insulin-like growth factor-I system

The stromal-specific proteoglycan decorin has emerged in recent years as a critical regulator of tumor initiation and progression. Decorin regulates the biology of various types of cancer by modulating the activity of several receptor tyrosine kinases coordinating growth, survival, migration, and angiogenesis. Decorin binds to surface receptors for epidermal growth factor and hepatocyte growth factor with high affinity, and negatively regulates their activity and signaling via robust internalization and eventual degradation. The insulin-like growth factor (IGF)-I system plays a critical role in the regulation of cell growth both in vivo and in vitro. The IGF-I receptor (IGF-IR) is also essential for cellular transformation, owing to its ability to enhance cell proliferation and protect cancer cells from apoptosis. Recent data have pointed to a role of decorin in regulating the IGF-I system in both nontransformed and transformed cells. Significantly, there is a surprising dichotomy in the mechanism of decorin action on IGF-IR signaling, which differs considerably between physiological and pathological cellular models. In this review, we summarize the current knowledge on decorin regulation of the IGF-I system in normal and transformed cells, and discuss possible decorin-based therapeutic approaches to target IGF-IR-driven tumors.

More than matrix: the multifaceted role of decorin in cancer

The small leucine-rich proteoglycan, decorin, has incrementally been shown to be a powerful inhibitor of growth in a wide variety of tumour cells, an effect specifically mediated by the interaction of decorin core protein with the epidermal growth factor receptor (EGFR) and other ErbB family proteins. Nowadays, this matrikine has become the main focus of various cancer studies. Decorin is an important component of the cellular microenvironment or extracellular matrix (ECM). Its interactions with matrix and cell membrane components have been implicated in many physiological and pathophysiological processes including matrix organisation, signal transduction, wound healing, cell migration, inhibition of metastasis, and angiogenesis. This review summarises recent findings on decorin's interactions and behaviour related to cancer. Highlighted are key functions of decorin such as interaction with cell surface receptors, as well as with ECM components, and the therapeutic potential of this multifunctional molecule.

Recombinant human decorin suppresses liver HepG2 carcinoma cells by p21 upregulation

Background

Decorin is a multifunctional molecule of the extracellular matrix and impedes different kinds of tumor cell growth, but the role and molecular mechanism by which decorin inhibits HepG2 cells is not fully understood. Our objective was to construct recombinant human decorin (pcDNA3.1-DCN) and to explore the mechanism by which it inhibits HepG2 cells.

Methods

This experiment was divided into three groups, ie, a control group, an empty vector group, and a pcDNA3.1-DCN group. pcDNA3.1-DCN was constructed using recombinant DNA technology, and the vector for pcDNA3.1-DCN and pcDNA3.1 was then transfected into HepG2 cells using Lipofectamine 2000.

Results

Compared with cells in the control group and in the empty vector group, growth of cells in the pcDNA3.1-DCN group was significantly suppressed, the ratios of cells in the G0/G1 phases and proportion of early apoptotic cells were significantly increased, and the level of p21^WAF1/CIP1 (p21) protein was markedly upregulated (P < 0.05). However, there was no significant difference among the three groups in p53 protein expression (P > 0.05).

Conclusion

The pcDNA3.1-DCN vector was successfully constructed and transfected into HepG2 cells, and decorin overexpression suppressed the growth of HepG2 cells by upregulation of p21 via a p53-independent pathway.

Proximal fluid proteome profiling of mouse colon tumors reveals biomarkers for early diagnosis of human colorectal cancer

PURPOSE

Early detection of colorectal cancer (CRC) and its precursor lesions is an effective approach to reduce CRC mortality rates. This study aimed to identify novel protein biomarkers for the early diagnosis of CRC.

EXPERIMENTAL DESIGN

Proximal fluids are a rich source of candidate biomarkers as they contain high concentrations of tissue-derived proteins. The FabplCre;Apc(15lox/+) mouse model represents early-stage development of human sporadic CRC. Proximal fluids were collected from normal colon and colon tumors and subjected to in-depth proteome profiling by tandem mass spectrometry. Carcinoembryonic antigen (CEA) and CHI3L1 human serum protein levels were determined by ELISA.

RESULTS

Of the 2,172 proteins identified, quantitative comparison revealed 192 proteins that were significantly (P < 0.05) and abundantly (>5-fold) more excreted by tumors than by controls. Further selection for biomarkers with highest specificity and sensitivity yielded 52 candidates, including S100A9, MCM4, and four other proteins that have been proposed as candidate biomarkers for human CRC screening or surveillance, supporting the validity of our approach. For CHI3L1, we verified that protein levels were significantly increased in sera from patients with adenomas and advanced adenomas compared with control individuals, in contrast to the CRC biomarker CEA.

CONCLUSION

These data show that proximal fluid proteome profiling with a mouse tumor model is a powerful approach to identify candidate biomarkers for early diagnosis of human cancer, exemplified by increased CHI3L1 protein levels in sera from patients with CRC precursor lesions.

Decorin antagonizes the angiogenic network: concurrent inhibition of Met, hypoxia inducible factor 1α, vascular endothelial growth factor A, and induction of thrombospondin-1 and TIMP3

Decorin, a small leucine-rich proteoglycan, inhibits tumor growth by antagonizing multiple receptor tyrosine kinases including EGFR and Met. Here, we investigated decorin during normoxic angiogenic signaling. An angiogenic PCR array revealed a profound decorin-evoked transcriptional inhibition of pro-angiogenic genes, such as HIF1A. Decorin evoked a reduction of hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor A (VEGFA) in MDA-231 breast carcinoma cells expressing constitutively-active HIF-1α. Suppression of Met with decorin or siRNA evoked a similar reduction of VEGFA by attenuating downstream β-catenin signaling. These data establish a noncanonical role for β-catenin in regulating VEGFA expression. We found that exogenous decorin induced expression of thrombospondin-1 and TIMP3, two powerful angiostatic agents. In contrast, decorin suppressed both the expression and enzymatic activity of matrix metalloprotease (MMP)-9 and MMP-2, two pro-angiogenic proteases. Our data establish a novel duality for decorin as a suppressor of tumor angiogenesis under normoxia by simultaneously down-regulating potent pro-angiogenic factors and inducing endogenous anti-angiogenic agents.

Decorin-mediated inhibition of colorectal cancer growth and migration is associated with E-cadherin in vitro and in mice

Previous studies have shown that decorin expression is significantly reduced in colorectal cancer tissues and cancer cells, and genetic deletion of the decorin gene is sufficient to cause intestinal tumor formation in mice, resulting from a downregulation of p21, p27(kip1) and E-cadherin and an upregulation of β-catenin signaling [Bi,X. et al. (2008) Genetic deficiency of decorin causes intestinal tumor formation through disruption of intestinal cell maturation. Carcinogenesis, 29, 1435-1440]. However, the regulation of E-cadherin by decorin and its implication in cancer formation and metastasis is largely unknown. Using a decorin knockout mouse model (Dcn(-/-) mice) and manipulated expression of decorin in human colorectal cancer cells, we found that E-cadherin, a protein that regulates cell-cell adhesion, epithelial-mesenchymal transition and metastasis, was almost completely lost in Dcn(-/-) mouse intestine, and loss of decorin and E-cadherin accelerated colon cancer cell growth and invasion in Dcn(-/-) mice. However, increasing decorin expression in colorectal cancer cells attenuated cancer cell malignancy, including inhibition of cancer cell proliferation, promotion of apoptosis and importantly, attenuation of cancer cell migration. All these changes were linked to the regulation of E-cadherin by decorin. Moreover, overexpression of decorin upregulated E-cadherin through increasing of E-cadherin protein stability as E-cadherin messenger RNA and promoter activity were not affected. Co-immunoprecipitation assay showed a physical binding between decorin and E-cadherin proteins. Taken together, our results provide direct evidence that decorin-mediated inhibition of colorectal cancer growth and migration are through the interaction with and stabilization of E-cadherin.

Decreased expression of decorin and p57(KIP2) correlates with poor survival and lymphatic metastasis in lung cancer patients

PURPOSE

Decorin, p57(KIP2), and TGF-beta 1 have been investigated as prognostic factors because they appear to be associated with tumorigenesis; however, the effect of decorin and p57(KIP2) in lung cancer remains poorly understood. The purpose of this study was to examine the expression of decorin, p57(KIP2), and TGF-beta 1 in 64 lung cancer specimens and 36 normal lung specimens, and to analyze the relationships with respect to clinicopathological features and patient survival in lung cancer.

METHODS

The expression levels of decorin, p57(KIP2), and TGF-beta 1 were examined by in situ hybridization and immunohistochemistry.

RESULTS

Normal tissues exhibited a higher expression level of decorin than tumor tissues (p<0.05) and tumor tissues exhibited a higher expression level of TGF-beta 1 than normal tissues (p<0.05). The expression levels of p57(KIP2) and TGF-beta 1 were significantly associated with histological types of lung cancer (p<0.05), and the expression levels of decorin and p57(KIP2) were significantly associated with lymphatic invasion (p<0.05). Moreover, increased expression of decorin and p57(KIP2) correlated with increased survival (decorin, p=0.018; p57(KIP2), p=0.012).

CONCLUSION

Decreased expression levels of decorin and p57(KIP2) were associated with poor postsurgical survival time and lymphatic metastasis in lung cancer patients; moreover, low expression was an adverse prognostic factor.

Effect of doublecortin on self-renewal and differentiation in brain tumor stem cells

Analysis of microarray probe data from glioma patient samples, in conjunction with patient Kaplan-Meier survival plots, indicates that expression of a glioma suppressor gene doublecortin (DCX) favors glioma patient survival. From neurosphere formation in culture, time-lapse microscopic video recording, and tumor xenograft, we show that DCX synthesis significantly reduces self-renewal of brain tumor stem cells (BTSC) in human primary glioma (YU-PG, HF66) cells from surgically removed human glioma specimens and U87 cells in vitro and in vivo. Time-lapse microscopic video recording revealed that double transfection of YU-PG, HF66, and U87 cells with DCX and neurabin II caused incomplete cell cycle with failure of cytokinesis, that is, endomitosis by dividing into three daughter cells from one mother BTSC. Activation of c-jun NH2-terminal kinase 1 (JNK1) after simvastatin (10 nM) treatment of DCX(+) neurabin II(+) BTSC from YU-PG, HF66, and U87 cells induced terminal differentiation into neuron-like cells. dUTP nick end labeling data indicated that JNK1 activation also induced apoptosis only in double transfected BTSC with DCX and neurabin II, but not in single transfected BTSC from YU-PG, HF66, and U87 cells. Western blot analysis showed that procaspase-3 was induced after DCX transfection and activated after simvastatin treatment in YU-PG, HF66, and U87 BTSC. Sequential immunoprecipitation and Western blot data revealed that DCX synthesis blocked protein phosphatase-1 (PP1)/caspase-3 protein-protein interaction and increased PP1-DCX interaction. These data show that DCX synthesis induces apoptosis in BTSC through a novel JNK1/neurabin II/DCX/PP1/caspase-3 pathway.

Decorin is a novel VEGFR-2-binding antagonist for the human extravillous trophoblast

Extravillous trophoblasts (EVT) of the human placenta invade the uterine decidua and its arteries to ensure successful placentation. We previously identified two decidua-derived molecules, TGF-β and a TGF-β-binding proteoglycan decorin (DCN), as negative regulators of EVT proliferation, migration, and invasiveness and reported that DCN acts via multiple tyrosine kinase receptors [epidermal growth factor-receptor (EGF-R), IGF receptor-1 (IGFR1), and vascular endothelial growth factor 2 receptor (VEGFR-2)]. Because binding of DCN to VEGFR-2 has never been reported earlier, present study explored this binding, the approximate location of VEGFR-2-binding site in DCN, and its functional role in our human first trimester EVT cell line HTR-8/SVneo. Based on far-Western blotting and coimmunoprecipitation studies, we report that DCN binds both native (EVT expressed) and recombinant VEGFR-2 and that this binding is abrogated with a VEGFR-2 blocking antibody, indicating an overlap between the ligand-binding and the DCN-binding domains of VEGFR-2. We determined that (125)I-labeled VEGF-E (a VEGFR-2 specific ligand) binds EVT with a dissociation constant (K(d)) of 566 pM, and DCN displaced this binding with an inhibition constant (K(i)) of 3.93-5.78 nM, indicating a 7- to 10-fold lower affinity of DCN for VEGFR-2. DCN peptide fragments derived from the leucine rich repeat 5 domain that blocked DCN-VEGFR-2 interactions or VEGF-E binding in EVT cells also blocked VEGF-A- and VEGF-E-induced EVT cell proliferation and migration, indicative of functional VEGFR-2-binding sites of DCN. Finally, DCN inhibited VEGF-E-induced EVT migration by interfering with ERK1/2 activation. Our findings reveal a novel role of DCN as an antagonistic ligand for VEGFR-2, having implications for pathophysiology of preeclampsia, a trophoblast hypoinvasive disorder in pregnancy, and explain its antiangiogenic function.

Mitostatin is down-regulated in human prostate cancer and suppresses the invasive phenotype of prostate cancer cells

MITOSTATIN, a novel putative tumor suppressor gene induced by decorin overexpression, is expressed in most normal human tissues but is markedly down-regulated in advanced stages of mammary and bladder carcinomas. Mitostatin negatively affects cell growth, induces cell death and regulates the expression and activation levels of Hsp27. In this study, we demonstrated that ectopic expression of Mitostatin in PC3, DU145, and LNCaP prostate cancer cells not only induced a significant reduction in cell growth, but also inhibited migration and invasion. Moreover, Mitostatin inhibited colony formation in soft-agar of PC3 and LNCaP cells as well as tumorigenicity of LNCaP cells in nude mice. Conversely, targeting endogenous Mitostatin by siRNA and anti-sense strategies in PC3 and DU145 prostate cancer cells enhanced the malignant phenotype in both cell lines. In agreement of these anti-oncogenic roles, we discovered that Mitostatin was absent in ∼35% (n = 124) of prostate tumor samples and its overall reduction was associated with advanced cancer stages. Collectively, our findings indicate that MITOSTATIN may acts as a tumor suppressor gene in prostate cancer and provide a novel cellular and molecular mechanism to be further exploited and deciphered in our understanding of prostate cancer progression.

Proteoglycans in cancer biology, tumour microenvironment and angiogenesis

Proteoglycans, key molecular effectors of cell surface and pericellular microenvironments, perform multiple functions in cancer and angiogenesis by virtue of their polyhedric nature and their ability to interact with both ligands and receptors that regulate neoplastic growth and neovascularization. Some proteoglycans such as perlecan, have pro- and anti-angiogenic activities, whereas other proteoglycans, such as syndecans and glypicans, can also directly affect cancer growth by modulating key signalling pathways. The bioactivity of these proteoglycans is further modulated by several classes of enzymes within the tumour microenvironment: (i) sheddases that cleave transmembrane or cell-associated syndecans and glypicans, (ii) various proteinases that cleave the protein core of pericellular proteoglycans and (iii) heparanases and endosulfatases which modify the structure and bioactivity of various heparan sulphate proteoglycans and their bound growth factors. In contrast, some of the small leucine-rich proteoglycans, such as decorin and lumican, act as tumour repressors by physically antagonizing receptor tyrosine kinases including the epidermal growth factor and the Met receptors or integrin receptors thereby evoking anti-survival and pro-apoptotic pathways. In this review we will critically assess the expanding repertoire of molecular interactions attributed to various proteoglycans and will discuss novel proteoglycan functions modulating cancer progression, invasion and metastasis and how these factors regulate the tumour microenvironment.

Differential epithelial and stromal protein profiles in keratoconus and normal human corneas

The purpose of the study was to identify epithelial and stromal proteins that exhibit up- or down-regulation in keratoconus (KC) vs. normal human corneas. Because previous proteomic studies utilized whole human corneas or epithelium alone, thereby diluted the specificity of the proteome of each tissue, we selectively analyzed the epithelium and stromal proteins. Individual preparations of epithelial and stromal proteins from KC and age-matched normal corneas were analyzed by two independent methods, i.e., a shotgun proteomic using a Nano-Electrospray Ionization Liquid Chromatography Tandem Mass Spectrometry [Nano-ESI-LC-MS (MS)(2)] and two-dimensional-difference gel electrophoresis (2D-DIGE) coupled with mass spectrometric methods. The label-free Nano-ESI-LC-MS (MS)(2) method identified 104 epithelial and 44 stromal proteins from both normal and KC corneas, and also quantified relative changes in levels of selected proteins, in both the tissues using spectral counts in a proteomic dataset. Relative to normal corneal epithelial proteins, six KC epithelial proteins (lamin-A/C, keratin type I cytoskeletal 14, tubulin beta chain, heat shock cognate 71 kDa protein, keratin type I cytoskeletal 16 and protein S100-A4) exhibited up-regulation and five proteins (transketolase, pyruvate kinase, 14-3-3 sigma isoform, phosphoglycerate kinase 1, and NADPH dehydrogenase (quinone) 1) showed down-regulation. A similar relative analysis showed that three KC stromal proteins (decorin, vimentin and keratocan) were up-regulated and five stromal proteins (TGF-betaig h3 (Bigh3), serotransferrin, MAM domain-containing protein 2 and isoforms 2C2A of collagen alpha-2[VI] chain) were down-regulated. The 2D-DIGE-mass spectrometry followed by Decyder software analysis showed that relative to normal corneas, the KC corneal epithelium exhibited up-regulation of four proteins (serum albumin, keratin 5, L-lactate dehydrogenase and annexin A8) and down-regulation of four proteins (FTH1 [Ferritin heavy chain protein 1], calpain small subunit 1, heat shock protein beta 1 and annexin A2). A similar relative analysis of stroma by this method also showed up-regulation of aldehyde dehydrogenase 3A1 (ALDH3A1), keratin 12, apolipoprotein A-IV precursor, haptoglobin precursor, prolipoprotein and lipoprotein Gln in KC corneas. Together, the results suggested that the Nano-ESI-LC-MS(MS)(2) method was superior than the 2D-DIGE method as it identified a greater number of proteins with altered levels in KC corneas. Further, the epithelial and stromal structural proteins of KC corneas exhibited altered levels compared to normal corneas, suggesting that they are affected due to structural remodeling during KC development and progression. Additionally, because several epithelial and stromal enzymes exhibited up- or down-regulation in the KC corneas relative to normal corneas, the two layers of KC corneas were under metabolic stress to adjust their remodeling.

Intratumoral drug delivery with nanoparticulate carriers

Stiff extracellular matrix, elevated interstitial fluid pressure, and the affinity for the tumor cells in the peripheral region of a solid tumor mass have long been recognized as significant barriers to diffusion of small-molecular-weight drugs and antibodies. However, their impacts on nanoparticle-based drug delivery have begun to receive due attention only recently. This article reviews biological features of many solid tumors that influence transport of drugs and nanoparticles and properties of nanoparticles relevant to their intratumoral transport, studied in various tumor models. We also discuss several experimental approaches employed to date for enhancement of intratumoral nanoparticle penetration. The impact of nanoparticle distribution on the effectiveness of chemotherapy remains to be investigated and should be considered in the design of new nanoparticulate drug carriers.

Decorin antagonizes Met receptor activity and down-regulates {beta}-catenin and Myc levels

A theme emerging during the past few years is that members of the small leucine-rich proteoglycan gene family affect cell growth by interacting with multiple receptor tyrosine kinases (RTKs), mostly by a physical down-regulation of the receptors, thereby depriving tumor cells of pro-survival signals. Decorin binds and down-regulates several RTKs, including Met, the receptor for hepatocyte growth factor. Here we demonstrate that decorin blocks several biological activities mediated by the Met signaling axis, including cell scatter, evasion, and migration. These effects were mediated by a profound down-regulation of noncanonical β-catenin levels. In addition, Myc, a downstream target of β-catenin, was markedly down-regulated by decorin, whereas phosphorylation of Myc at threonine 58 was markedly induced. The latter is known to destabilize Myc and target it for proteasomal degradation. We also discovered that systemic delivery of decorin using three distinct tumor xenograft models caused down-regulation of Met and a concurrent suppression of β-catenin and Myc levels. We found that decorin protein core labeled with the near infrared dye IR800 specifically targeted the tumor cells expressing Met. Even 68-h post-injection, decorin was found to reside within the tumor xenografts with little or no binding to other tissues. Collectively, our results indicate a role for a secreted proteoglycan in suppressing the expression of key oncogenic factors required for tumor progression.

Proteoglycans in health and disease: novel regulatory signaling mechanisms evoked by the small leucine-rich proteoglycans

The small leucine-rich proteoglycans (SLRPs) are involved in many aspects of mammalian biology, both in health and disease. They are now being recognized as key signaling molecules with an expanding repertoire of molecular interactions affecting not only growth factors, but also various receptors involved in controlling cell growth, morphogenesis and immunity. The complexity of SLRP signaling and the multitude of affected signaling pathways can be reconciled with a hierarchical affinity-based interaction of various SLRPs in a cell- and tissue-specific context. Here, we review this interacting network, describe new relationships of the SLRPs with tyrosine kinase and Toll-like receptors and critically assess their roles in cancer and innate immunity.

Fibroblast and prostate tumor cell cross-talk: fibroblast differentiation, TGF-β, and extracellular matrix down-regulation

Growth and survival of tumors at a site of metastasis involve interactions with stromal cells in the surrounding environment. Stromal cells aid tumor cell growth by producing cytokines as well as by modifying the environment surrounding the tumor through modulation of the extracellular matrix (ECM). Small leucine-rich proteoglycans (SLRPs) are biologically active components of the ECM which can be altered in the stroma surrounding tumors. The influence tumor cells have on stromal cells has been well elucidated. However, little is understood about the effect metastatic cancer cells have on the cell biology and behavior of the local stromal cells. Our data reveal a significant down-regulation in the expression of ECM components such as collagens I, II, III, and IV, and the SLRPs, decorin, biglycan, lumican, and fibromodulin in stromal cells when grown in the presence of two metastatic prostate cancer cell lines PC3 and DU145. Interestingly, TGF-β down-regulation was observed in stromal cells, as well as actin depolymerization and increased vimentin and α5β1 integrin expression. MT1-MMP expression was upregulated and localized in stromal cell protrusions which extended into the ECM. Moreover, enhanced stromal cell migration was observed after cross-talk with metastatic prostate tumor cells. Xenografting metastatic prostate cancer cells together with "activated" stromal cells led to increased tumorigenicity of the prostate cancer cells. Our findings suggest that metastatic prostate cancer cells create a metastatic niche by altering the phenotype of local stromal cells, leading to changes in the ECM.

Decorin suppresses prostate tumor growth through inhibition of epidermal growth factor and androgen receptor pathways

Epidermal growth factor receptor (EGFR) and androgen receptor (AR) pathways play pivotal roles in prostate cancer progression. Therefore, agents with dual-targeting ability may have important therapeutic potential. Decorin, a proteoglycan present in the tumor microenvironment, is known to regulate matrix assembly, growth factor binding, and receptor tyrosine kinase activity. Here, we show that in prostate-specific Pten(P-/-) mice, a genetically defined, immune-competent mouse model of prostate cancer, systemic delivery of decorin inhibits tumor progression by targeting cell proliferation and survival pathways. Moreover, in human prostate cancer cells, we show that decorin specifically inhibits EGFR and AR phosphorylation and cross talk between these pathways. This prevents AR nuclear translocation and inhibits the production of prostate specific antigen. Further, the phosphatidylinositol-3 kinase (PI3K)/Akt cell survival pathway is suppressed leading to tumor cell apoptosis. Those findings highlight the effectiveness of decorin in the presence of a powerful genetic cancer risk and implicate decorin as a potential new agent for prostate cancer therapy by targeting EGFR/AR-PI3K-Akt pathways.