Lumican and decorin are differentially expressed in human breast carcinoma

Proteomic profiling of formalin-fixed paraffine-embedded tissue reveals key proteins related to lung dysfunction in idiopathic pulmonary fibrosis

Introduction

Idiopathic pulmonary fibrosis (IPF) severely affects the lung leading to aberrant deposition of extracellular matrix and parenchymal stiffness with progressive functional derangement. The limited availability of fresh tissues represents one of the major limitations to study the molecular profiling of IPF lung tissue. The primary aim of this study was to explore the proteomic profiling yield of archived formalin-fixed paraffin-embedded (FFPE) specimens of IPF lung tissues.

Methods

We further determined the protein expression according to respiratory functional decline at the time of biopsy. The total proteins isolated from 11 FFPE samples of IPF patients compared to 3 FFPE samples from a non-fibrotic lung defined as controls, were subjected to label-free quantitative proteomic analysis by liquid chromatography-mass spectrometry (LC-MS/MS) and resulted in the detection of about 400 proteins.

Results

After the pairwise comparison between controls and IPF, functional enrichment analysis identified differentially expressed proteins that were involved in extracellular matrix signaling pathways, focal adhesion and transforming growth factor β (TGF-β) signaling pathways strongly associated with IPF onset and progression. Five proteins were significantly over- expressed in the lung of IPF patients with either advanced disease stage (Stage II) or impaired pulmonary function (FVC<75, DLCO<55) compared to controls; these were lymphocyte cytosolic protein 1 (LCP1), peroxiredoxin-2 (PRDX2), transgelin 2 (TAGLN2), lumican (LUM) and mimecan (OGN) that might play a key role in the fibrogenic processes.

Discussion

Our work showed that the analysis of FFPE samples was able to identify key proteins that might be crucial for the IPF pathogenesis. These proteins are correlated with lung carcinogenesis or involved in the immune landscape of lung cancer, thus making possible common mechanisms between lung carcinogenesis and fibrosis progression, two pathological conditions at risk for each other in the real life.

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.

Assessment of Ovarian Tumor Growth in Wild-Type and Lumican-Deficient Mice: Insights Using Infrared Spectral Imaging, Histopathology, and Immunohistochemistry

Simple Summary

Lumican, a small leucine-rich proteoglycan (SLRP), maintains extracellular matrix (ECM) integrity while inhibiting melanoma primary tumor development, as well as metastatic spread. The aim of this study was to analyze the effect of lumican on tumor growth of murine ovarian carcinoma. C57BL/6 wild type mice (n = 12) and lumican-deficient mice (n = 10) were subcutaneously injected with murine ovarian epithelial carcinoma ID8 cells, and sacrificed after 18 days. Label-free infrared spectral imaging (IRSI) generated high contrast IR images allowing identification of different ECM regions of the skin and the ovarian tumor. IRSI showed a good correlation with collagen distribution as well as organization, as analyzed using second harmonic generation imaging within the tumor area. The results demonstrated that lumican inhibited the growth of ovarian cancer mainly by altering collagen fibrilogenesis.

Abstract

Ovarian cancer remains one of the most fatal cancers due to a lack of robust screening methods of detection at early stages. Extracellular matrix (ECM) mediates interactions between cancer cells and their microenvironment via specific molecules. Lumican, a small leucine-rich proteoglycan (SLRP), maintains ECM integrity and inhibits both melanoma primary tumor development, as well as metastatic spread. The aim of this study was to analyze the effect of lumican on tumor growth of murine ovarian epithelial cancer. C57BL/6 wild type mice (n = 12) and lumican-deficient mice (n = 10) were subcutaneously injected with murine ovarian epithelial carcinoma ID8 cells, and then sacrificed after 18 days. Analysis of tumor volumes demonstrated an inhibitory effect of endogenous lumican on ovarian tumor growth. The ovarian primary tumors were subjected to histological and immunohistochemical staining using anti-lumican, anti-αv integrin, anti-CD31 and anti-cyclin D1 antibodies, and then further examined by label-free infrared spectral imaging (IRSI), second harmonic generation (SHG) and Picrosirius red staining. The IR tissue images allowed for the identification of different ECM tissue regions of the skin and the ovarian tumor. Moreover, IRSI showed a good correlation with αv integrin immunostaining and collagen organization within the tumor. Our results demonstrate that lumican inhibits ovarian cancer growth mainly by altering collagen fibrilogenesis.

Differential MMP-14 Targeting by Lumican-Derived Peptides Unraveled by In Silico Approach

Lumican, a small leucine-rich proteoglycan (SLRP) of the extracellular matrix (ECM), displays anti-tumor properties through its direct interaction with MMP-14. Lumican-derived peptides, such as lumcorin (17 amino acids) or L9M (10 amino acids), are able to inhibit the proteolytic activity of MMP-14 and melanoma progression. This work aimed to visualize the interactions of lumican-derived peptides and MMP-14. Molecular modeling was used to characterize the interactions between lumican-derived peptides, such as lumcorin, L9M, and cyclic L9M (L9Mc, 12 amino acids), and MMP-14. The interaction of L9Mc with MMP-14 was preferential with the MT-Loop domain while lumcorin interacted more with the catalytic site. Key residues in the MMP-14 amino acid sequence were highlighted for the interaction between the inhibitory SLRP-derived peptides and MMP-14. In order to validate the in silico data, MMP-14 activity and migration assays were performed using murine B16F1 and human HT-144 melanoma cells. In contrast to the HT-144 melanoma cell line, L9Mc significantly inhibited the migration of B16F1 cells and the activity of MMP-14 but with less efficacy than lumican and lumcorin. L9Mc significantly inhibited the proliferation of B16F1 but not of HT-144 cells in vitro and primary melanoma tumor growth in vivo. Thus, the site of interaction between the domains of MMP-14 and lumcorin or L9Mc were different, which might explain the differences in the inhibitory effect of MMP-14 activity. Altogether, the biological assays validated the prediction of the in silico study. Possible and feasible improvements include molecular dynamics results.

Comprehensive Proteomic Analysis of Colon Cancer Tissue Revealed the Reason for the Worse Prognosis of Right-Sided Colon Cancer and Mucinous Colon Cancer at the Protein Level

To clarify the molecular mechanisms underlying the poor prognosis of right-sided and mucinous colon cancer at the proteomic level. A tandem mass tag-proteomics approach was used to identify differentially expressed proteins (DEPs) in colon carcinoma tissues from different locations and with different histological types to reveal the underlying mechanisms of these differences at the protein level. In additional, the DEPs were analyzed using bioinformatics methods. The proteomics profiles among colon cancers with different tumor locations and histological types were dramatically distinguished. In terms of tumor locations, the right-sided carcinoma specific DEPs may promote the tumor progression via activating inflammation, metastasis associated pathways. When referring to histological types, the mucinous colon cancers perhaps increased the invasion and metastasis through distinct mechanisms in different tumor locations. For mucinous cancer located in right-sided colon, the mucinous specific DEPs were mainly associated with ECM-related remodeling and the IL-17 signal pathway. For mucinous cancer located in left-sided colon, the mucinous specific DEPs showed a strong relationship with ACE2/Ang-(1–7)/MasR axis. The proteomics profiles of colon cancers showed distinct differences related to locations and histological types. These results suggested a distinct mechanism underlying the diverse subtypes of colon cancers.

Mechanical Pressure Driving Proteoglycan Expression in Mammographic Density: a Self-perpetuating Cycle?

Regions of high mammographic density (MD) in the breast are characterised by a proteoglycan (PG)-rich fibrous stroma, where PGs mediate aligned collagen fibrils to control tissue stiffness and hence the response to mechanical forces. Literature is accumulating to support the notion that mechanical stiffness may drive PG synthesis in the breast contributing to MD. We review emerging patterns in MD and other biological settings, of a positive feedback cycle of force promoting PG synthesis, such as in articular cartilage, due to increased pressure on weight bearing joints. Furthermore, we present evidence to suggest a pro-tumorigenic effect of increased mechanical force on epithelial cells in contexts where PG-mediated, aligned collagen fibrous tissue abounds, with implications for breast cancer development attributable to high MD. Finally, we summarise means through which this positive feedback mechanism of PG synthesis may be intercepted to reduce mechanical force within tissues and thus reduce disease burden.

Down-Regulation of the Proteoglycan Decorin Fills in the Tumor-Promoting Phenotype of Ionizing Radiation-Induced Senescent Human Breast Stromal Fibroblasts

Simple Summary

Ionizing radiation (a typical remedy for breast cancer) results in the premature senescence of the adjacent to the neoplastic cells stromal fibroblasts. Here, we showed that these senescent fibroblasts are characterized by the down-regulation of the small leucine-rich proteoglycan decorin, a poor prognostic factor for the progression of the disease. Decorin down-regulation is mediated by secreted growth factors in an autocrine and paracrine (due to the interaction with breast cancer cells) manner, with bFGF and VEGF being the key players of this regulation in young and senescent breast stromal fibroblasts. Autophagy activation increases decorin mRNA levels, indicating that impaired autophagy is implicated in the reduction in decorin in this cell model. Decorin down-regulation acts additively to the already tumor-promoting phenotype of ionizing radiation-induced prematurely senescent human stromal fibroblasts, confirming that stromal senescence is a side-effect of radiotherapy that should be taken into account in the design of anticancer treatments.

Abstract

Down-regulation of the small leucine-rich proteoglycan decorin in the stroma is considered a poor prognostic factor for breast cancer progression. Ionizing radiation, an established treatment for breast cancer, provokes the premature senescence of the adjacent to the tumor stromal fibroblasts. Here, we showed that senescent human breast stromal fibroblasts are characterized by the down-regulation of decorin at the mRNA and protein level, as well as by its decreased deposition in the pericellular extracellular matrix in vitro. Senescence-associated decorin down-regulation is a long-lasting process rather than an immediate response to γ-irradiation. Growth factors were demonstrated to participate in an autocrine manner in decorin down-regulation, with bFGF and VEGF being the critical mediators of the phenomenon. Autophagy inhibition by chloroquine reduced decorin mRNA levels, while autophagy activation using the mTOR inhibitor rapamycin enhanced decorin transcription. Interestingly, the secretome from a series of both untreated and irradiated human breast cancer cell lines with different molecular profiles inhibited decorin expression in young and senescent stromal fibroblasts, which was annulled by SU5402, a bFGF and VEGF inhibitor. The novel phenotypic trait of senescent human breast stromal fibroblasts revealed here is added to their already described cancer-promoting role via the formation of a tumor-permissive environment.

99mTc-Radiolabeled Silica Nanocarriers for Targeted Detection and Treatment of HER2-Positive Breast Cancer

INTRODUCTION

The overexpression of Human Epidermal Growth Factor Receptor 2 (HER2) is usually associated with aggressive and infiltrating breast cancer (BC) phenotype, and metastases. Functionalized silica-based nanocarriers (SiNPs) can be labeled for in vivo imaging applications and loaded with chemotherapy drugs, making possible the simultaneous noninvasive diagnosis and treatment (theranostic) for HER2-positive BC.

METHODS

Firstly, FITC-filled SiNPs, were engineered with two different amounts of Hc-TZ (trastuzumab half-chain) per single nanoparticle (1:2 and 1:8, SiNPs to Hc-TZ ratio), which was 99mTc-radiolabeled at histidine residues for ex vivo and in vivo biodistribution evaluations. Secondly, nanoparticles were loaded with DOX and their in vitro and ex vivo/in vivo delivery was assessed, in comparison with liposomal Doxorubicin (Caelyx). Finally, the treatment efficacy of DOX-SiNPs-TZ (1:8 Hc-TZ) was evaluated in vivo by PET and supported by MS-based proteomics profiling of tumors.

RESULTS

SiNPs-TZ (1:8 Hc-TZ) tumor uptake was significantly greater than that of SiNPs-TZ (1:2 Hc-TZ) at 6 hours post-injection (p.i.) in ex vivo biodistribution experiment. At 24 h p.i., radioactivity values remained steady. Fluorescence microscopy, confirmed the presence of radiolabeled SiNPs-TZ (1:8 Hc-TZ) within tumor even at later times. SiNPs-TZ (1:8 Hc-TZ) nanoparticles loaded with Doxorubicin (DOX-SiNPs-TZ) showed a similar DOX delivery capability than Caelyx (at 6 h p.i.), in in vitro and ex vivo assays. Nevertheless, at the end of treatment, tumor volume was significantly reduced by DOX-SiNPs-TZ (1:8 Hc-TZ), compared to Caelyx and DOX-SiNPs treatment. Proteomics study identified 88 high stringent differentially expressed proteins comparing the three treatment groups with controls.

CONCLUSION

These findings demonstrated a promising detection specificity and treatment efficacy for our system (SiNPs-TZ, 1:8 Hc-TZ), encouraging its potential use as a new theranostic agent for HER2-positive BC lesions. In addition, proteomic profile confirmed that a set of proteins, related to tumor aggressiveness, were positively affected by targeted nanoparticles.

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.

Proteoglycans in the Pathogenesis of Hormone-Dependent Cancers: Mediators and Effectors

Hormone-dependent cancers exhibit high morbidity and mortality. In spite of advances in therapy, the treatment of hormone-dependent cancers remains an unmet health need. The tumor microenvironment (TME) exhibits unique characteristics that differ among various tumor types. It is composed of cancerous, non-cancerous, stromal, and immune cells that are surrounded and supported by components of the extracellular matrix (ECM). Therefore, the interactions among cancer cells, stromal cells, and components of the ECM determine cancer progression and response to therapy. Proteoglycans (PGs), hybrid molecules consisting of a protein core to which sulfated glycosaminoglycan chains are bound, are significant components of the ECM that are implicated in all phases of tumorigenesis. These molecules, secreted by both the stroma and cancer cells, are crucial signaling mediators that modulate the vital cellular pathways implicated in gene expression, phenotypic versatility, and response to therapy in specific tumor types. A plethora of deregulated signaling pathways contributes to the growth, dissemination, and angiogenesis of hormone-dependent cancers. Specific inputs from the endocrine and immune systems are some of the characteristics of hormone-dependent cancer pathogenesis. Importantly, the mechanisms involved in various aspects of cancer progression are executed in the ECM niche of the TME, and the PG components crucially mediate these processes. Here, we comprehensively discuss the mechanisms through which PGs affect the multifaceted aspects of hormone-dependent cancer development and progression, including cancer metastasis, angiogenesis, immunobiology, autophagy, and response to therapy.

Systematic prediction of key genes for ovarian cancer by co-expression network analysis

Ovarian cancer (OC) is the most lethal gynaecological malignancy, characterized by high recurrence and mortality. However, the mechanisms of its pathogenesis remain largely unknown, hindering the investigation of the functional roles. This study sought to identify key hub genes that may serve as biomarkers correlated with prognosis. Here, we conduct an integrated analysis using the weighted gene co‐expression network analysis (WGCNA) to explore the clinically significant gene sets and identify candidate hub genes associated with OC clinical phenotypes. The gene expression profiles were obtained from the MERAV database. Validations of candidate hub genes were performed with RNASeqV2 data and the corresponding clinical information available from The Cancer Genome Atlas (TCGA) database. In addition, we examined the candidate genes in ovarian cancer cells. Totally, 19 modules were identified and 26 hub genes were extracted from the most significant module (R² = .53) in clinical stages. Through the validation of TCGA data, we found that five hub genes (COL1A1, DCN, LUM, POSTN and THBS2) predicted poor prognosis. Receiver operating characteristic (ROC) curves demonstrated that these five genes exhibited diagnostic efficiency for early‐stage and advanced‐stage cancer. The protein expression of these five genes in tumour tissues was significantly higher than that in normal tissues. Besides, the expression of COL1A1 was associated with the TAX resistance of tumours and could be affected by the autophagy level in OC cell line. In conclusion, our findings identified five genes could serve as biomarkers related to the prognosis of OC and may be helpful for revealing pathogenic mechanism and developing further research.

While Urine and Plasma Decorin Remain Unchanged in Prostate Cancer, Prostatic Tissue Decorin Has a Prognostic Value

Background

Numerous studies confirmed that significant decrease in tissue decorin (DCN) expression is associated to tumor progression and metastasis in certain types of cancer including prostate cancer (PC). However, the potential prognostic value of tissue DCN in PC has not yet been investigated.

Methods

A total number of 40 PC and 42 patients with benign prostatic hyperplasia (BPH) were investigated for the expression levels of DCN in their prostatic tissues using real-time quantitative polymerase chain reaction and immunohistochemical analyses. Urinary and plasma DCN levels were also measured by ELISA.

Results

Despite no significant changes in the mean of urine and plasma DCN concentrations between the two study groups, tissue DCN mRNA was found to be 5.5fold lower in cancer than BPH (p = 0.0001). Similarly, the stained DCN levels appeared significantly lower in cancer patients with higher Gleason Scores (8 and 9, n = 6) than those with lower Gleason Scores (6 and 7, n = 26), with a p value of 0.049.

Conclusion

Here, we report, for the first time, that urine and plasma DCN does not seem to have a diagnostic value in PC, while tissue DCN could potentially be used as a prognostic marker in PC.

Framing cancer progression: influence of the organ- and tumour-specific matrisome

The extracellular matrix (ECM) plays a crucial role in regulating organ homeostasis. It provides mechanical and biochemical cues directing cellular behaviour and, therefore, has control over the progression of diseases such as cancer. Recent efforts have greatly enhanced our knowledge of the protein composition of the ECM and its regulators, the so-called matrisome, in healthy and cancerous tissues; yet, an overview of the common signatures and organ-specific ECM in cancer is missing. Here, we address this by taking a detailed approach to review why cancer grows in certain organs, and focus on the influence of the matrisome at primary and metastatic tumour sites. Our in-depth and comprehensive review of the current literature and general understanding identifies important commonalities and distinctions, providing insight into the biology of metastasis, which could pave the way to improve future diagnostics and therapies.

Elevated Expression of Lumican in Lung Cancer Cells Promotes Bone Metastasis through an Autocrine Regulatory Mechanism

Background: The microarray analysis of whole-genome expression indicated that the gene encoding the protein lumican, which is associated with extracellular matrix (ECM) interaction, was highly expressed in osteotropic lung cancer cell lines with an enhanced capacity of bone metastasis. Methods: The expression of lumican in the osteotropic lung cancer cells was downregulated, and the in vitro migration, invasion, and adhesion of cancer cells to ECM components, and the in vivo bone metastasis capacity of these cells were examined. Exogenous lumican was provided to study the autocrine regulation mechanism of lumican in the bone metastasis of lung cancer cells. Results: Transfection with lumican-specific short hairpin RNA (shRNA) in the osteotropic lung cancer cells reduced the establishment of in vivo bone metastasis, but not lung metastasis. Reduction in the expression of lumican also decreased the attachment of lung osteotropic cancer cells to several components of the ECM and suppressed cell migration and invasion in vitro. Exogenous lumican restored these reduced capacities of lumican knockdown cells and promoted the seeding of lung cancer cells in the bone microenvironment. Conclusions: These results suggested that lumican promotes the metastasis of lung cancer cells to the bones via an autocrine regulatory mechanism, and blocking this interaction may provide a new therapeutic approach to reduce bone metastasis in cases of lung cancer.

The Tumor Microenvironment: Focus on Extracellular Matrix

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

Epithelial-to-mesenchymal transition and invadopodia markers in breast cancer: Lumican a key regulator

A great hallmark of breast cancer is the absence or presence of estrogen receptors ERα and ERβ, with a dominant role in cell proliferation, differentiation and cancer progression. Both receptors are related with Epithelial-to-Mesenchymal Transition (EMT) since there is a relation between ERs and extracellular matrix (ECM) macromolecules expression, and therefore, cell-cell and cell-ECM interactions. The endocrine resistance of ERα endows epithelial cells with increased aggressiveness and induces cell proliferation, resulting into a mesenchymal phenotype and an EMT status. ERα signaling may affect the transcriptional factors which govern EMT. Knockdown or silencing of ERα and ERβ in MCF-7 and MDA-MB-231 breast cancer cells respectively, provoked pivotal changes in phenotype, cellular functions, mRNA and protein levels of EMT markers, and consequently the EMT status. Mesenchymal cells owe their migratory and invasive properties to invadopodia, while in epithelial cells, lamellipodia and filopodia are mostly observed. Invadopodia, are actin-rich protrusions of plasma membrane, promoting proteolytic degradation of ECM and tumor invasion. Cortactin and MMP-14 govern the formation and principal functions of invadopodia. In vitro experiments proved that lumican inhibits cortactin and MMP-14 expression, alters the formation of lamellipodia and transforms mesenchymal cells into epithelial-like. Conclusively, lumican may inhibit or even reverse the several metastatic features that EMT endows in breast cancer cells. Therefore, a lumican-based anti-cancer therapy which will pharmacologically target and inhibit EMT might be interesting to be developed.

Knockdown of Lumican Inhibits Proliferation and Migration of Bladder Cancer

Lumican (LUM) is differentially expressed between normal and cancer tissues. The purpose of this study was to investigate the role of LUM in the proliferation and migration of bladder cancer (BCa) cells. Our study included 97 cases of BCa diagnosis from our hospital between June 2013 and June 2016. The expression of LUM was analyzed by immunohistochemistry and Western blot. To characterize the function of LUM, BCa cells were stably infected with a lentivirus against LUM, and cell proliferation, migration and cell cycle were investigated. In addition, xenograft experiments were performed in nude mice to evaluate the role of LUM in BCa. Our results showed that LUM was overexpressed in BCa tissues and cell lines in comparison to normal tissues. LUM expression was related to pathological type, T stage and N stage (P < .05). In addition, depletion of LUM inhibited the proliferation and migration of BCa cells by inactivating MAPK signaling. In conclusion, LUM promotes the proliferation and migration of BCa cells and may serve as a potential therapeutic target for BCa.

An overview of mammographic density and its association with breast cancer

In 2017, breast cancer became the most commonly diagnosed cancer among women in the US. After lung cancer, breast cancer is the leading cause of cancer-related mortality in women. The breast consists of several components, including milk storage glands, milk ducts made of epithelial cells, adipose tissue, and stromal tissue. Mammographic density (MD) is based on the proportion of stromal, epithelial, and adipose tissue. Women with high MD have more stromal and epithelial cells and less fatty adipose tissue, and are more likely to develop breast cancer in their lifetime compared to women with low MD. Because of this correlation, high MD is an independent risk factor for breast cancer. Further, mammographic screening is less effective in detecting suspicious lesions in dense breast tissue, which can lead to late-stage diagnosis. Molecular differences between dense and non-dense breast tissues explain the underlying biological reasons for why women with dense breasts are at a higher risk for developing breast cancer. The goal of this review is to highlight the current molecular understanding of MD, its association with breast cancer risk, the demographics pertaining to MD, and the environmental factors that modulate MD. Finally, we will review the current legislation regarding the disclosure of MD on a traditional screening mammogram and the supplemental screening options available to women with dense breast tissue.

Lumican as a multivalent effector in wound healing

Wound healing, a complex physiological process, is responsible for tissue repair after exposure to destructive stimuli, without resulting in complete functional regeneration. Injuries can be stromal or epithelial, and most cases of wound repair have been studied in the skin and cornea. Lumican, a small leucine-rich proteoglycan, is expressed in the extracellular matrices of several tissues, such as the cornea, cartilage, and skin. This molecule has been shown to regulate collagen fibrillogenesis, keratinocyte phenotypes, and corneal transparency modulation. Lumican is also involved in the extravasation of inflammatory cells and angiogenesis, which are both critical in stromal wound healing. Lumican is the only member of the small leucine-rich proteoglycan family expressed by the epithelia during wound healing. This review summarizes the importance of lumican in wound healing and potential methods of lumican drug delivery to target wound repair are discussed. The involvement of lumican in corneal wound healing is described based on in vitro and in vivo models, with critical emphasis on its underlying mechanisms of action. Similarly, the expression and role of lumican in the healing of other tissues are presented, with emphasis on skin wound healing. Overall, lumican promotes normal wound repair and broadens new therapeutic perspectives for impaired wound healing.

Proteoglycans remodeling in cancer: Underlying molecular mechanisms

Extracellular matrix is a highly dynamic macromolecular network. Proteoglycans are major components of extracellular matrix playing key roles in its structural organization and cell signaling contributing to the control of numerous normal and pathological processes. As multifunctional molecules, proteoglycans participate in various cell functions during morphogenesis, wound healing, inflammation and tumorigenesis. Their interactions with matrix effectors, cell surface receptors and enzymes enable them with unique properties. In malignancy, extensive remodeling of tumor stroma is associated with marked alterations in proteoglycans' expression and structural variability. Proteoglycans exert diverse functions in tumor stroma in a cell-specific and context-specific manner and they mainly contribute to the formation of a permissive provisional matrix for tumor growth affecting tissue organization, cell-cell and cell-matrix interactions and tumor cell signaling. Proteoglycans also modulate cancer cell phenotype and properties, the development of drug resistance and tumor stroma angiogenesis. This review summarizes the proteoglycans remodeling and their novel biological roles in malignancies with particular emphasis to the underlying molecular mechanisms.

The significance of lumican expression in ovarian cancer drug-resistant cell lines

PURPOSE

The aim of the present study is to determine the expression of LUM in drug-resistant ovarian cancer cell lines.

METHODS

Doxorubicin- (DOX), topotecan- (TOP) and vincristine- (VIN) resistant variants of the W1 ovarian cancer cell line were used in this study. We used quantitative real-time polymerase chain reactions to determine LUM mRNA levels. Protein expression was detected using Western blot and immunocytochemistry assays. Protein glycosylation was investigated using PGNase F digestion. Immunohistochemistry assays were used to determine protein expression in ovarian cancer patients.

RESULTS

We observed increased expression of LUM in drug-resistant cell lines at both the mRNA and the protein level. The most abundant LUM expression was observed in TOP-resistant cell line. We observed LUM bands that corresponded to different molecular masses, and the most abundant LUM form was the secreted form, which had a mass of 50 kDa. Double immunofluorescence analysis showed co-expression of LUM and COL3A1 as well as the presence of extracellular COL3A1 in the TOP-resistant cell line. Finally, we detected the LUM protein in ovarian cancer tissue.

CONCLUSION

The expression of LUM in cytostatic-resistant cell lines suggests its role in drug resistance. The co-expression of LUM and COL3A1 indicates the significance of LUM in collagen fibre assembly. Expression in ovarian cancer tissue suggests that LUM can play a role in ovarian cancer pathogenesis in ways similar to other cancers.

Human Metaplastic Breast Carcinoma and Decorin

Metaplastic breast carcinoma (MBC) is a rare subtype of invasive breast cancer and has poor prognosis. In general, cancers are heterogeneous cellular masses comprised of different cell types and their extracellular matrix (ECM). However, little is known about the composition of the ECM and its constituents in MBC. Decorin is a ubiquitous ECM macromolecule known of its oncosuppressive activity. As such, it provides an intriguing molecule in the development of novel therapeutics for different malignancies such as MBC. In this study, decorin immunoreactivity and the effect of adenoviral decorin cDNA (Ad-DCN) transduction were examined in MBC. Multiple immunohistochemical stainings were used to characterize a massive breast tumour derived from an old woman. Furthermore, three-dimensional (3D) explant cultures derived from the tumour were transduced with Ad-DCN to study the effect of the transduction on the explants. The MBC tumour was shown to be completely negative for decorin immunoreactivity demonstrating that the malignant cells were not able to synthesize decorin. Ad-DCN transduction resulted in a markedly altered cytological phenotype of MBC explants by decreasing the amount of atypical cells and by inhibiting cell proliferation. The results of this study support approaches to develop new, decorin-based adjuvant therapies for MBC.

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.

Lumican effectively regulates the estrogen receptors-associated functional properties of breast cancer cells, expression of matrix effectors and epithelial-to-mesenchymal transition

Lumican is a small leucine-rich proteoglycan that has been shown to contribute in several physiological processes, but also to exert anticancer activity. On the other hand, it has been recently shown that knockdown of the estrogen receptor α (ERα) in low invasive MCF-7 (ERα+) breast cancer cells and the suppression of ERβ in highly aggressive MDA-MB-231 (ERβ+) cells significantly alter the functional properties of breast cancer cells and the gene expression profile of matrix macromolecules related to cancer progression and cell morphology. In this report, we evaluated the effects of lumican in respect to the ERs-associated breast cancer cell behaviour, before and after suppression of ERs, using scanning electron and confocal microscopies, qPCR and functional assays. Our data pinpointed that lumican significantly attenuated cell functional properties, including proliferation, migration and invasion. Furthermore, it modified cell morphology, inducing cell-cell junctions, evoked EMT/MET reprogramming and suppressed the expression of major matrix effectors (matrix metalloproteinases and EGFR) implicated in breast cancer progression. The effects of lumican were found to be related to the type of breast cancer cells and the ERα/β type. These data support the anticancer activity of lumican and open a new area for the pharmacological targeting of the invasive breast cancer.

The method for breast cancer grade prediction and pathway analysis based on improved multiple kernel learning

Breast cancer histologic grade represents the morphological assessment of the tumor’s malignancy and aggressiveness, which is vital in clinically planning treatment and estimating prognosis for patients. Therefore, the prediction of breast cancer grade can markedly elevate the detection of early breast cancer and efficiently guide its treatment. With the advent of high-throughput profiling technology, a large number of data of different types are rapidly generated, and each data provides its unique biological insight. Although many researches focused on cancer grade prediction, hardly most of them attempted to integrate multiple data types, by which we cannot only improve and boost results obtained from learning method, but also have a good understanding or explanation of biological issues. In this paper, we take advantage of a sophisticated supervised learning method called multiple kernel learning (MKL) to design a breast cancer grading predictor fusing heterogeneous data for classification of breast cancer histopathology. Furthermore, we modify our model by involving biological pathway information. The new model can evaluate the significance of various pathways in which differential expression genes fall between different breast cancer grades. The merits of the novel model are lucubration in bridging between omics data and various phenotypes of breast cancer grades, and providing an auxiliary method integrating omics data of cancer mechanism research. In experiments, the proposed method outperforms other state-of-the-art methods and has abundant biological interpretation in explaining differences between breast cancer grades.

Tumor angiogenesis of SCLC inhibited by decreased expression of FMOD via downregulating angiogenic factors of endothelial cells

Fibromodulin (FMOD), an ECM small leucine-rich proteoglycan (SLRP), was reported to promote angiogenesis not only during wound healing, but also in optical and cutaneous angiogenesis-dependent diseases. However, whether it plays important roles in tumor angiogenesis remains unclear. To explore the role of FMOD in tumor angiogenesis of human small cell lung cancer (SCLC), initially the study analyzed the relationship of FMOD expression in cancer tissues of SCLC with clinical characteristics. The analysis revealed that the positive FMOD expression was significantly associated with extensive stage of SCLC and higher vascular density. In mouse models, xenograft tumors developed with FMOD-silenced H446 cells (H446-shFMOD) exhibited slowed growth rate, decreased microvessel density, and reduced blood perfusion related to that of controls (H446-shCON). Additionally, compared with that of controls, the decreased secretion of FMOD in conditioned medium (CM) from H446-shFMOD inhibited proliferation, migration, and invasion of human umbilical vessel endothelial cells (HUVECs). Moreover, the decreased secretion of FMOD downregulated the expression of VEGF, TGF-β1, FGF-2, and PDGF-B in HUVECs. The findings strongly suggested that the autocrine FMOD of cancer cells may promote tumor angiogenesis of SCLC by upregulating the expression of angiogenic factors that act in concert to facilitate the angiogenic phenotype of endothelial cells as a proangiogenic factor. Therefore, silencing FMOD may be a potentially clinical therapy for repressing tumor angiogenesis.

Epithelial cells captured from ductal carcinoma in situ reveal a gene expression signature associated with progression to invasive breast cancer

Breast cancer biomarkers that can precisely predict the risk of progression of non-invasive ductal carcinoma in situ (DCIS) lesions to invasive disease are lacking. The identification of molecular alterations that occur during the invasion process is crucial for the discovery of drivers of transition to invasive disease and, consequently, biomarkers with clinical utility. In this study, we explored differences in gene expression in mammary epithelial cells before and after the morphological manifestation of invasion, i.e., early and late stages, respectively. In the early stage, epithelial cells were captured from both pre-invasive lesions with distinct malignant potential [pure DCIS as well as the in situ component that co-exists with invasive breast carcinoma lesions (DCIS-IBC)]; in the late stage, epithelial cells were captured from the two distinct morphological components of the same sample (in situ and invasive components). Candidate genes were identified using cDNA microarray and rapid subtractive hybridization (RaSH) cDNA libraries and validated by RT-qPCR assay using new samples from each group. These analyses revealed 26 genes, including 20 from the early and 6 from the late stage. The expression profile based on the 20 genes, marked by a preferential decrease in expression level towards invasive phenotype, discriminated the majority of DCIS samples. Thus, this study revealed a gene expression signature with the potential to predict DCIS progression and, consequently, provides opportunities to tailor treatments for DCIS patients.

Extracellular matrix structure

Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented.

The extracellular matrix in breast cancer

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

Prognostic value of stromal decorin expression in patients with breast cancer: a meta-analysis

BACKGROUND

Numbers of studies have investigated the biological functions of decorin (DCN) in oncogenesis, tumor progression, angiogenesis and metastasis. Although many of them aim to highlight the prognostic value of stromal DCN expression in breast cancer, some controversial results still exist and a consensus has not been reached until now. Therefore, our meta-analysis aims to determine the prognostic significance of stromal DCN expression in breast cancer patients.

METHODS

PubMed, EMBASE, the Web of Science and China National Knowledge Infrastructure (CNKI) databases were searched for full-text literatures met out inclusion criteria. We applied the hazard ratio (HR) with 95% confidence interval (CI) as the appropriate summarized statistics. Q-test and I(2) statistic were employed to estimate the level of heterogeneity across the included studies. Sensitivity analysis was conducted to further identify the possible origins of heterogeneity. The publication bias was detected by Begg's test and Egger's test.

RESULTS

There were three English literatures (involving 6 studies) included into our meta-analysis. On the one hand, both the summarized outcomes based on univariate analysis (HR: 0.513; 95% CI: 0.406-0.648; P<0.001) and multivariate analysis (HR: 0.544; 95% CI: 0.388-0.763; P<0.001) indicated that stromal DCN expression could promise the high cancer-specific survival (CSS) of breast cancer patients. On the other hand, both the summarized outcomes based on univariate analysis (HR: 0.504; 95% CI: 0.389-0.651; P<0.001) and multivariate analysis (HR: 0.568; 95% CI: 0.400-0.806; P=0.002) also indicated that stromal DCN expression was positively associated with high disease-free survival (DFS) of breast cancer patients. No significant heterogeneity or publication bias was observed within this meta-analysis.

CONCLUSIONS

The present evidences indicate that high stromal DCN expression can significantly predict the good prognosis in patients with breast cancer. The discoveries from our meta-analysis have better be confirmed in the updated review pooling more relevant investigations in the future.

Proteoglycans: Potential Agents in Mammographic Density and the Associated Breast Cancer Risk

Although increased mammographic density (MD) has been well established as a marker for increased breast cancer (BC) risk, its pathobiology is far from understood. Altered proteoglycan (PG) composition may underpin the physical properties of MD, and may contribute to the associated increase in BC risk. Numerous studies have investigated PGs, which are a major stromal matrix component, in relation to MD and BC and reported results that are sometimes discordant. Our review summarises these results and highlights discrepancies between PG associations with BC and MD, thus serving as a guide for identifying PGs that warrant further research towards developing chemo-preventive or therapeutic agents targeting preinvasive or invasive breast lesions, respectively.

The extracellular matrix in breast cancer predicts prognosis through composition, splicing, and crosslinking

The extracellular matrix in the healthy breast has an important tumor suppressive role, whereas the abnormal ECM in tumors can promote aggressiveness, and has been linked to breast cancer relapse, survival and resistance to chemotherapy. This review article gives an overview of the elements of the ECM which have been linked to prognosis of breast cancers, including changes in ECM protein composition, splicing, and microstructure.

The Extracellular Matrix in Epithelial Ovarian Cancer - A Piece of a Puzzle

Epithelial ovarian cancer is the fifth leading cause of cancer-related deaths in women and the most lethal gynecological malignancy. Extracellular matrix (ECM) is an integral component of both the normal and tumor microenvironment. ECM composition varies between tissues and is crucial for maintaining normal function and homeostasis. Dysregulation and aberrant deposition or loss of ECM components is implicated in ovarian cancer progression. The mechanisms by which tumor cells induce ECM remodeling to promote a malignant phenotype are yet to be elucidated. A thorough understanding of the role of the ECM in ovarian cancer is needed for the development of effective biomarkers and new therapies.

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.

Oncosuppressive functions of decorin

The extracellular matrix is rapidly emerging as a prominent contributor to various fundamental processes of tumorigenesis. In particular, decorin, a member of the small leucine-rich proteoglycan gene family, is assuming a central role as a potent soluble tumor repressor. Decorin binds and antagonizes various receptor tyrosine kinases and inhibits downstream oncogenic signaling in several solid tumors. Among other functions, decorin evokes cell cycle arrest, apoptosis, and antimetastatic, and antiangiogenic programs. Recent work has revealed a paradigmatic shift in our understanding of the molecular mechanisms underlying its tumoricidal properties. Decorin adversely compromises the genetic signature of the tumor microenvironment and induces endothelial cell autophagy downstream of VEGFR2. Moreover, decorin selectively evokes destruction of tumor cell mitochondria downstream of Met through mitophagy. Acting as a partial agonist, decorin signals via proautophagic receptors and triggers procatabolic processes that parallel the classical tumoricidal properties of this multifaceted proteoglycan.

Decorin is responsible for progression of non-small-cell lung cancer by promoting cell proliferation and metastasis

Decorin, a member of the small leucine-rich proteoglycans family, exists and plays multifunctional roles in stromal and epithelial cells. Emerging evidences showed that decorin is dysregulated expression in a wide variety of human tumors and affects a broad biology process of cancer cells, including growth, metastasis, and angiogenesis. Recent studies demonstrated that decorin could affect A549 proliferation though decreasing TGF-β1, cycling D1 expression and increasing P53 and P21 expression. However, limited data are available on the effect of decorin on metastasis of non-small-cell lung cancer (NSCLC) cell lines and how decorin impacts metastasis is still unknown. In this study, we identified decorin mRNA expression through Oncomine database and verified the expression of decorin mRNA and protein in 50 patients who underwent primary surgical resection of a NSCLC in the Department of Thoracic Surgery, Jinling Hospital, Nanjing University School of Medicine, China, between September 2013 and March 2014 by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot. Also, the correlationship between decorin and the NSCLC patients' clinical characteristics or survival ( www.kmplot.com ) was analyzed. Via ectopic expression analyses and Western blot, the roles of decorin in proliferation, metastasis, and the underline mechanism for decorin expression were further explored. We found that decorin was downregulated in NSCLC tissues compared with the adjacent normal lung tissues or normal tissues. Additionally, the expression of decorin was correlated with tumor size, lymph node metastasis, tumor stage, and prognosis. We also showed that overexpression of decorin could inhibit NSCLC cell lines proliferation and metastasis. Through Western blot analysis, we identified that E-cadherin and vascular endothelial growth factor (VEGF) are two key factors responsible for the growth arrest and metastasis inhibition induced by decorin in NSCLC. Our results indicated that decorin plays crucial roles in NSCLC against carcinogenesis and progression. Decorin might be a predictive factor and an attractive therapeutic target for NSCLC patients.

Extracellular lumican inhibits pancreatic cancer cell growth and is associated with prolonged survival after surgery

PURPOSE

To evaluate the relevance between lumican expression patterns and the clinical course of patients with pancreatic ductal adenocarcinoma (PDAC), and to investigate the role of lumican in PDAC progression.

EXPERIMENTAL DESIGN

One hundred thirty-one patient tumors were chosen for tissue microarray staining, and Cox regression analysis was used to test the associations between lumican expression and clinical, pathologic, and oncologic outcomes in all patients. Primary PDAC cells and recombinant human lumican protein were used to establish a working model to mimic the in vivo interactions between stromal lumican and PDAC cells. Using this model, we tested the effects of lumican on EGFR signaling via Akt and hypoxia-inducible factor-1α (HIF1α) and its subsequent influence on glucose consumption, lactate production, intracellular ATP, and apoptotic cell death.

RESULTS

Lumican was present in the stroma surrounding PDAC cells in roughly one-half of primary tumors and the direct xenografts. Patients with stromal lumican were associated with a profound reduction in metastatic recurrence after surgery and 3-fold longer survival than patients without stromal lumican. In PDAC cells, extracellular lumican reduced EGFR expression and phosphorylation through enhanced dimerization and internalization of EGFR and the resultant inhibition of Akt kinase activity. Lumican also reduced HIF1α expression and activity via Akt. PDAC cells with enhanced HIF1α activity were resistant to lumican-induced inhibition of glucose consumption, lactate production, intracellular ATP, and apoptosis.

CONCLUSIONS

There is a positive association between stromal lumican in primary PDAC tumors and prolonged survival after tumor resection. Lumican plays a restrictive role in EGFR-expressing pancreatic cancer progression.

Periostin suppression induces decorin secretion leading to reduced breast cancer cell motility and invasion

The ability of cancer cells to metastasize is dependent on the interactions between their cell-surface molecules and the microenvironment. However, the tumor microenvironment, especially the cancer-associated stroma, is poorly understood. To identify proteins present in the stroma, we focused on phyllodes tumors, rare breast tumors that contain breast stromal cells. We compared the expression of proteins between phyllodes tumor and normal tissues using an iTRAQ-based quantitative proteomic approach. Decorin was expressed at reduced levels in phyllodes tumor tissues, whereas periostin was upregulated; this result was validated by immunohistochemical analysis of phyllodes tumors from 35 patients. Additionally, by immunoprecipitation and mass spectrometry, we confirmed that decorin forms a complex with periostin in both phyllodes tumors and BT-20 breast cancer cells. Following siRNA-mediated knockdown of periostin in T-47D cells, secreted decorin in the culture medium could be detected by multiple reaction monitoring (MRM). Furthermore, periostin knockdown in BT-20 cells and overexpression of decorin in MDA-MB-231 cells inhibited cell motility and invasion. Our results reveal the molecular details of the periostin–decorin complex in both phyllodes tumor tissues and breast cancer cells; this interaction may represent a novel target for anti-cancer therapy.

The motile breast cancer phenotype roles of proteoglycans/glycosaminoglycans

The consecutive stages of cancer growth and dissemination are obligatorily perpetrated through specific interactions of the tumor cells with their microenvironment. Importantly, cell-associated and tumor microenvironment glycosaminoglycans (GAGs)/proteoglycan (PG) content and distribution are markedly altered during tumor pathogenesis and progression. GAGs and PGs perform multiple functions in specific stages of the metastatic cascade due to their defined structure and ability to interact with both ligands and receptors regulating cancer pathogenesis. Thus, GAGs/PGs may modulate downstream signaling of key cellular mediators including insulin growth factor receptor (IGFR), epidermal growth factor receptor (EGFR), estrogen receptors (ERs), or Wnt members. In the present review we will focus on breast cancer motility in correlation with their GAG/PG content and critically discuss mechanisms involved. Furthermore, new approaches involving GAGs/PGs as potential prognostic/diagnostic markers or as therapeutic agents for cancer-related pathologies are being proposed.

Proteomic analysis of equine amniotic membrane: characterization of proteins

INTRODUCTION

Human amniotic membrane (AM) has been used as a biomaterial for surgical wound skin and ocular surface reconstruction for several years. Currently, equine AM has been used for corneal reconstruction in several animal species, and appears to have the same properties as human AM. Despite the observed positive healing abilities of this tissue in horses with ulcerative keratitis the proteins of equine AM have not been described.

OBJECTIVE

To identify proteins known to be associated with corneal healing from frozen equine AM.

PROCEDURES

Placentas were acquired from healthy live foal births from a local Thoroughbred breeding farm. The amnion was removed from the chorion by blunt dissection, washed with phosphate-buffered saline (PBS), and treated with 0.05% trypsin and 0.02% ethylene diaminetetraacetic acid in PBS. Amnion was attached to nitrocellulose paper (epithelial side up), and cut into 4 × 4 cm pieces. The sheets were frozen at -80 °C. The protein samples were solubilized, and analyzed by 2D gel electrophoresis and shotgun proteomics.

RESULTS

A reference identification map of the equine AM proteins was produced and 149 different proteins were identified. From gel-based proteomics, 49 spots were excised and 43 proteins identified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Shotgun proteomics identified 116 proteins with an overlap of 10 proteins in both analyses.

CONCLUSIONS

We have described a reference map for equine AM proteins that may provide a background to explain the positive results found in horses with ulcerative keratopathies using this biomaterial.

Complex influence of dermatan sulphate on breast cancer cells

Tumor transformation and progression both lead to extracellular matrix remodeling, which is also reflected in an alteration in the proportion of dermatan sulphate (DS) and chondroitin sulphate (CS) and an accumulation of the latter. In addition, a significant increase in the 6-O-sulphated disaccharide contribution to the structure of both glycosaminoglycans has been observed. It is commonly accepted that CS is more permissive for tumor growth than DS. However, the detailed role of DS in tumor progression is poorly known. We tested the effects of structurally different DSs on the behavior of cultured breast cancer cells. At a high dose (10 µg/mL), all of the DSs significantly reduced cancer cell growth, although some differences in the efficiency of action were apparent. In contrast, when used at a concentration of 1 µg/mL, the examined DSs evoked different responses ranging from the stimulation to the inhibition of cancer cell proliferation. The highest stimulatory activity was associated with fibrosis-affected fascia decorin DS, which is characterized by a particularly high content of 6-O-sulphated disaccharides. Further reduction in DS concentration to 0.5 µg/mL preserved majority of biological effects which were apparent at a dose of 1 µg/mL. The enzymatic fragmentation of the DSs, particularly by chondroitinase AC I, abolished the impact exerted by 1 µg/mL of the intact DS chains and sometimes resulted in the opposite effect. In contrast to DSs, highly sulphated C-6-S exhibited no effect on the cancer cells. Our data revealed the complexity of the effects of DSs on breast cancer cells, which include both co-receptor activity and the prevention of vascular endothelial growth factor action. In addition, the biological effect of DSs is strongly dependent not only on the glycosaminoglycan structure but also on its content in the cancer environment.

Ductal carcinoma in situ of the breast: morphological and molecular features implicated in progression

The spread of mammographic screening programmes around the world, including in developing countries, has substantially contributed to the diagnosis of small non-palpable lesions, which has increased the detection rate of DCIS (ductal carcinoma in situ). DCIS is heterogeneous in several ways, such as its clinical presentation, morphology and genomic profile. Excellent outcomes have been reported; however, many questions remain unanswered. For example, which patients groups are overtreated and could instead benefit from minimal intervention and which patient groups require a more traditional multidisciplinary approach. The development of a comprehensive integrated analysis that includes the radiological, morphological and genetic aspects of DCIS is necessary to answer these questions. This review focuses on discussing the significant findings about the morphological and molecular features of DCIS and its progression that have helped to uncover the biological and genetic heterogeneity of this disease. The knowledge gained in recent years might allow the development of tailored clinical management for women with DCIS in the future.

Cross-talk between estradiol receptor and EGFR/IGF-IR signaling pathways in estrogen-responsive breast cancers: focus on the role and impact of proteoglycans

In hormone-dependent breast cancer, estrogen receptors are the principal signaling molecules that regulate several cell functions either by the genomic pathway acting directly as transcription factors in the nucleus or by the non-genomic pathway interacting with other receptors and their adjacent pathways like EGFR/IGFR. It is well established in literature that EGFR and IGFR signaling pathways promote cell proliferation and differentiation. Moreover, recent data indicate the cross-talk between ERs and EGFR/IGFR signaling pathways causing a transformation of cell functions as well as deregulation on normal expression pattern of matrix molecules. Specifically, proteoglycans, a major category of extracellular matrix (ECM) and cell surface macromolecules, are modified during malignancy and cause alterations in cancer cell signaling, affecting eventually functional cell properties such as proliferation, adhesion and migration. The on-going strategies to block only one of the above signaling effectors result cancer cells to overcome such inactivation using alternative signaling pathways. In this article, we therefore review the underlying mechanisms in respect to the role of ERs and the involvement of cross-talk between ERs, IGFR and EGFR in breast cancer cell properties and expression of extracellular secreted and cell bound proteoglycans involved in cancer progression. Understanding such signaling pathways may help to establish new potential pharmacological targets in terms of using ECM molecules to design novel anticancer therapies.

Stromal architecture and periductal decorin are potential prognostic markers for ipsilateral locoregional recurrence in ductal carcinoma in situ of the breast

AIMS

The incidence of ductal carcinoma in situ (DCIS) has increased since the introduction of screening mammography. Recurrence prediction is still not accurate, and could be improved by identifying additional prognostic markers. Periductal stroma actively participates in early breast cancer progression. Therefore, the aim of this study was to explore the prognostic potential of stromal characteristics in DCIS.

METHODS AND RESULTS

Histopathological features and hormone receptor/HER2 status were analysed in a first cohort of 65 cases of DCIS with a median follow-up of 112 months. Cox regression analysis revealed that myxoid stromal architecture was significantly associated with increased ipsilateral locoregional recurrence (P = 0.015). Next, we performed immunohistochemical screening of nine stromal proteins in a second cohort of 82 DCIS cases, and correlated their expression with stromal architecture. Because reduced stromal decorin expression correlated most strongly with myxoid stroma (P < 0.001), it was selected for further analysis in the first cohort. Patients with reduced periductal decorin expression had a higher risk of recurrence (P = 0.008). Furthermore, HER2 overexpression was significantly associated with invasive but not with in situ recurrence (P = 0.007).

CONCLUSIONS

Periductal myxoid stroma and reduced periductal decorin expression seem to be prognostic for overall ipsilateral locoregional recurrence in DCIS, whereas HER2 expression might be a more specific biomarker for invasive recurrence.

Ovarian cancer molecular pathology

Ovarian cancer (OVC) is the fourth leading cause of cancer mortality among women in Europe and the United States. Its early detection is difficult due to the lack of specificity of clinical symptoms. Unfortunately, late diagnosis is a major contributor to the poor survival rates for OVC, which can be attributed to the lack of specific sets of markers. Aside from patients sharing a strong family history of ovarian and breast cancer, including the BRCA1 and BRCA2 tumor suppressor genes mutations, the most used biomarker is the Cancer-antigen 125 (CA-125). CA-125 has a sensitivity of 80 % and a specificity of 97 % in epithelial cancer (stage III or IV). However, its sensitivity is 30 % in stage I cancer, as its increase is linked to several physiological phenomena and benign situations. CA-125 is particularly useful for at-risk population diagnosis and to assess response to treatment. It is clear that alone, CA-125 is inadequate as a biomarker for OVC diagnosis. There is an unmet need to identify additional biomarkers. Novel and more sensitive proteomic strategies such as MALDI mass spectrometry imaging studies are well suited to identify better markers for both diagnosis and prognosis. In the present review, we will focus on such proteomic strategies in regards to OVC signaling pathways, OVC development and escape from the immune response.

Lumican effects in the control of tumour progression and their links with metalloproteinases and integrins

Lumican is a member of the small leucine-rich proteoglycan family. It is present in numerous extracellular matrices of different tissues, such as muscle, cartilage, and cornea. In skin, lumican is present as a glycoprotein. It plays a critical role in collagen fibrillogenesis, as shown by knocking out of its gene in mice. A direct link between lumican expression and melanoma progression and metastasis has been demonstrated. Lumican was shown to impede tumour cell migration and invasion by directly interacting with the α2β1 integrin. In addition, an active sequence of the lumican core protein, called lumcorin, was identified as being responsible for inhibition of melanoma cell migration. Lumican was also shown to exert angiostatic properties by downregulating the proteolytic activity associated with endothelial cell membranes, particularly matrix metalloproteinase (MMP)-14 and MMP-9. Globally, lumican appears to be a potent agent for inhibiting tumour progression rather than tumorigenesis. However, progressive changes in proteoglycans occur in the tumour environment. The complexity and diversity of proteoglycan structure might be responsible for a variety of functions that regulate cell behaviour. Through their core protein and their glycosaminoglycan chains, proteoglycans can interact with growth factors and chemokines. These interactions affect cell signalling, motility, adhesion, growth, and apoptosis. This review summarizes recent data concerning lumican control of tumour progression in different cancers, with a particular focus on its interactions with MMPs and integrins. Its potential therapeutic implications are discussed.

Proteoglycans and their roles in brain cancer

Glioblastoma, a malignant brain cancer, is characterized by abnormal activation of receptor tyrosine kinase signalling pathways and a poor prognosis. Extracellular proteoglycans, including heparan sulfate and chondroitin sulfate, play critical roles in the regulation of cell signalling and migration via interactions with extracellular ligands, growth factor receptors and extracellular matrix components, as well as intracellular enzymes and structural proteins. In cancer, proteoglycans help drive multiple oncogenic pathways in tumour cells and promote critical tumour-microenvironment interactions. In the present review, we summarize the evidence for proteoglycan function in gliomagenesis and examine the expression of proteoglycans and their modifying enzymes in human glioblastoma using data obtained from The Cancer Genome Atlas (http://cancergenome.nih.gov/). Furthermore, we demonstrate an association between specific proteoglycan alterations and changes in receptor tyrosine kinases. Based on these data, we propose a model in which proteoglycans and their modifying enzymes promote receptor tyrosine kinase signalling and progression in glioblastoma, and we suggest that cancer-associated proteoglycans are promising biomarkers for disease and therapeutic targets.