Co-stimulation of human breast cancer cells with transforming growth factor-beta and tenascin-C enhances matrix metalloproteinase-9 expression and cancer cell invasion

The Role of Extracellular Matrix Proteins in Breast Cancer

The extracellular matrix is a structure composed of many molecules, including fibrillar (types I, II, III, V, XI, XXIV, XXVII) and non-fibrillar collagens (mainly basement membrane collagens: types IV, VIII, X), non-collagenous glycoproteins (elastin, laminin, fibronectin, thrombospondin, tenascin, osteopontin, osteonectin, entactin, periostin) embedded in a gel of negatively charged water-retaining glycosaminoglycans (GAGs) such as non-sulfated hyaluronic acid (HA) and sulfated GAGs which are linked to a core protein to form proteoglycans (PGs). This highly dynamic molecular network provides critical biochemical and biomechanical cues that mediate the cell–cell and cell–matrix interactions, influence cell growth, migration and differentiation and serve as a reservoir of cytokines and growth factors’ action. The breakdown of normal ECM and its replacement with tumor ECM modulate the tumor microenvironment (TME) composition and is an essential part of tumorigenesis and metastasis, acting as key driver for malignant progression. Abnormal ECM also deregulate behavior of stromal cells as well as facilitating tumor-associated angiogenesis and inflammation. Thus, the tumor matrix modulates each of the classically defined hallmarks of cancer promoting the growth, survival and invasion of the cancer. Moreover, various ECM-derived components modulate the immune response affecting T cells, tumor-associated macrophages (TAM), dendritic cells and cancer-associated fibroblasts (CAF). This review article considers the role that extracellular matrix play in breast cancer. Determining the detailed connections between the ECM and cellular processes has helped to identify novel disease markers and therapeutic targets.

Tenascin-C Induces Phenotypic Changes in Fibroblasts to Myofibroblasts with High Contractility through the Integrin αvβ1/Transforming Growth Factor β/SMAD Signaling Axis in Human Breast Cancer

Tenascin-C (TNC) is strongly expressed by fibroblasts and cancer cells in breast cancer. To assess the effects of TNC on stromal formation, we examined phenotypic changes in human mammary fibroblasts treated with TNC. The addition of TNC significantly up-regulated α-smooth muscle actin (α-SMA) and calponin. TNC increased the number of α-SMA- and/or calponin-positive cells with well-developed stress fibers in immunofluorescence, which enhanced contractile ability in collagen gel contraction. The treatment with TNC also significantly up-regulated its own synthesis. Double immunofluorescence of human breast cancer tissues showed α-SMA- and/or calponin-positive myofibroblasts in the TNC-deposited stroma. Among several receptors for TNC, the protein levels of the αv and β1 integrin subunits were significantly increased after the treatment. Immunofluorescence showed the augmented colocalization of αv and β1 at focal adhesions. Immunoprecipitation using an anti-αv antibody revealed a significant increase in coprecipitated β1 with TNC in lysates. The knockdown of αv and β1 suppressed the up-regulation of α-SMA and calponin. The addition of TNC induced the phosphorylation of SMAD2/3, whereas SB-505124 and SIS3 blocked myofibroblast differentiation. Therefore, TNC enhances its own synthesis by forming a positive feedback loop and increases integrin αvβ1 heterodimer levels to activate transforming growth factor-β signaling, which is followed by a change to highly contractile myofibroblasts. TNC may essentially contribute to the stiffer stromal formation characteristic of breast cancer tissues.

Extracellular Matrix Derived from High Metastatic Human Breast Cancer Triggers Epithelial-Mesenchymal Transition in Epithelial Breast Cancer Cells through αvβ3 Integrin

Alterations in the composition and architecture of the extracellular matrix (ECM) can influence cancer growth and dissemination. During epithelial-mesenchymal transition (EMT), epithelial cells assume a mesenchymal cell phenotype, changing their adhesion profiles from cell-cell contacts to cell-matrix interactions, contributing to metastasis. Breast cancer cells present at different stages of differentiation, producing distinct ECMs in the same tumor mass. However, the contribution of ECM derived from metastatic tumor cells to EMT is unclear. Here, we showed the mechanisms involved in the interaction of MCF-7, a low-metastatic, epithelial breast cancer cell line, with the ECM produced by a high metastatic breast tumor cell, MDA-MB-231 (MDA-ECM). MDA-ECM induced morphological changes in MCF-7 cells, decreased the levels of E-cadherin, up-regulated mesenchymal markers, and augmented cell migration. These changes were accompanied by the activation of integrin-associated signaling, with increased phosphorylation of FAK, ERK, and AKT and activation canonical TGF-β receptor signaling, enhancing phosphorylation of SMAD2 and SMAD4 nuclear translocation in MCF-7 cells. Treatment with Kistrin (Kr), a specific ligand of integrin αvβ3 EMT induced by MDA-ECM, inhibited TGF-β receptor signaling in treated MCF-7 cells. Our results revealed that after interaction with the ECM produced by a high metastatic breast cancer cell, MCF-7 cells lost their characteristic epithelial phenotype undergoing EMT, an effect modulated by integrin signaling in crosstalk with TGF-β receptor signaling pathway. The data evidenced novel potential targets for antimetastatic breast cancer therapies.

Agonists and knockdown of estrogen receptor β differentially affect invasion of triple-negative breast cancer cells in vitro

Background

Estrogen receptor β (ERβ) is expressed in the majority of invasive breast cancer cases, irrespective of their subtype, including triple-negative breast cancer (TNBC). Thus, ERβ might be a potential target for therapy of this challenging cancer type. In this in vitro study, we examined the role of ERβ in invasion of two triple-negative breast cancer cell lines.

Methods

MDA-MB-231 and HS578T breast cancer cells were treated with the specific ERβ agonists ERB-041, WAY200070, Liquiritigenin and 3β-Adiol. Knockdown of ERβ expression was performed by means of siRNA transfection. Effects on cellular invasion were assessed in vitro by means of a modified Boyden chamber assay. Transcriptome analyses were performed using Affymetrix Human Gene 1.0 ST microarrays. Pathway and gene network analyses were performed by means of Genomatix and Ingenuity Pathway Analysis software.

Results

Invasiveness of MBA-MB-231 and HS578T breast cancer cells decreased after treatment with ERβ agonists ERB-041 and WAY200070. Agonists Liquiritigenin and 3β-Adiol only reduced invasion of MDA-MB-231 cells. Knockdown of ERβ expression increased invasiveness of MDA-MB-231 cells about 3-fold. Transcriptome and pathway analyses revealed that ERβ knockdown led to activation of TGFβ signalling and induced expression of a network of genes with functions in extracellular matrix, tumor cell invasion and vitamin D3 metabolism.

Conclusions

Our data suggest that ERβ suppresses invasiveness of triple-negative breast cancer cells in vitro. Whether ERβ agonists might be useful drugs in the treatment of triple-negative breast cancer, has to be evaluated in further animal and clinical studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2973-y) contains supplementary material, which is available to authorized users.

Deficiency of tenascin-C and attenuation of blood-brain barrier disruption following experimental subarachnoid hemorrhage in mice

OBJECT Tenascin-C (TNC), a matricellular protein, is induced in the brain following subarachnoid hemorrhage (SAH). The authors investigated if TNC causes brain edema and blood-brain barrier (BBB) disruption following experimental SAH. METHODS C57BL/6 wild-type (WT) or TNC knockout (TNKO) mice were subjected to SAH by endovascular puncture. Ninety-seven mice were randomly allocated to WT sham-operated (n = 16), TNKO sham-operated (n = 16), WT SAH (n = 34), and TNKO SAH (n = 31) groups. Mice were examined by means of neuroscore and brain water content 24-48 hours post-SAH; and Evans blue dye extravasation and Western blotting of TNC, matrix metalloproteinase (MMP)-9, and zona occludens (ZO)-1 at 24 hours post-SAH. As a separate study, 16 mice were randomized to WT sham-operated, TNKO sham-operated, WT SAH, and TNKO SAH groups (n = 4 in each group), and activation of mitogen-activated protein kinases (MAPKs) was immunohistochemically evaluated at 24 hours post-SAH. Moreover, 40 TNKO mice randomly received an intracerebroventricular injection of TNC or phosphate-buffered saline, and effects of exogenous TNC on brain edema and BBB disruption following SAH were studied. RESULTS Deficiency of endogenous TNC prevented neurological impairments, brain edema formation, and BBB disruption following SAH; it was also associated with the inhibition of both MMP-9 induction and ZO-1 degradation. Endogenous TNC deficiency also inhibited post-SAH MAPK activation in brain capillary endothelial cells. Exogenous TNC treatment abolished the neuroprotective effects shown in TNKO mice with SAH. CONCLUSIONS Tenascin-C may be an important mediator in the development of brain edema and BBB disruption following SAH, mechanisms for which may involve MAPK-mediated MMP-9 induction and ZO-1 degradation. TNC could be a molecular target against which to develop new therapies for SAH-induced brain injuries.

Extracellular matrix components in breast cancer progression and metastasis

The extracellular matrix (ECM) is composed of highly variable and dynamic components that regulate cell behavior. The protein composition and physical properties of the ECM govern cell fate through biochemical and biomechanical mechanisms. This requires a carefully orchestrated and thorough regulation considering that a disturbed ECM can have serious consequences and lead to pathological conditions like cancer. In breast cancer, many ECM proteins are significantly deregulated and specific matrix components promote tumor progression and metastatic spread. Intriguingly, several ECM proteins that are associated with breast cancer development, overlap substantially with a group of ECM proteins induced during the state of tissue remodeling such as mammary gland involution. Fibrillar collagens, fibronectin, hyaluronan and matricellular proteins are matrix components that are common to both involution and cancer. Moreover, some of these proteins have in recent years been identified as important constituents of metastatic niches in breast cancer. In addition, specific ECM molecules, their receptors or enzymatic modifiers are significantly involved in resistance to therapeutic intervention. Further analysis of these ECM proteins and the downstream ECM mediated signaling pathways may provide a range of possibilities to identify druggable targets against advanced breast cancer.

High serum transforming growth factor beta 1 (TGFB1) level predicts better survival in breast cancer

The transforming growth factor beta 1 (TGFB1) is a regulatory cytokine with both tumor suppressor and tumor-promoting effects in breast cancer (BC) cell lines and tissue. Data about level of circulating TGFB1 and its prognostic significance in BC patients is conflicting. The objective of this study is to determine the clinical significance of the serum TGFB1 levels in BC patients. We enrolled 96 female patients with histopathologically diagnosed BC who did not receive chemotherapy (CT) or radiotherapy. Serum TGFB1 levels were measured by ELISA method and compared with 30 healthy controls. The mean serum TGFB1 level of BC patients was significantly higher than controls (0.08 vs. 0.04 ng/ml, p < 0.001). There was no significant difference according to known disease-related clinicopathological or laboratory parameters. Serum TGFB1 level had a significant impact on overall survival in both univariate (p = 0.01) and multivariate analysis (p = 0.013). Serum TGFB1 level is elevated in BC patients and has a favorable prognostic value. However, it has no predictive role on CT response.

Curcumin inhibits TGF-β1-induced MMP-9 and invasion through ERK and Smad signaling in breast cancer MDA- MB-231 cells

OBJECTIVE

To evaluate the effects of curcumin on matrixmetalloproteinase-9 (MMP-9) and invasion ability induced by transforming growth factor-β1 (TGF-β1) in MDA-MB-231 cells and potential mechanisms.

METHODS

Human breast cancer MDA- MB-231 cells were used with the CCK-8 assay to measure the cytotoxicity of curcumin. After treatment with 10 ng/ml TGF-β1, with or without curcumin (≤10 μM), cell invasion was checked by transwell chamber. The effects of curcumin on TGF-β1-stimulated MMP-9 and phosphorylation of Smad2, extracellular-regulated kinase (ERK), and p38 mitogen activated protein kinases (p38MAPK) were examined by Western blotting. Supernatant liquid were collected to analyze the activity of MMP-9 via zymography. Following treatment with PD98059, a specific inhibitor of ERK, and SB203580, a specific inhibitor of p38MAPK, Western blotting and zymography were employed to examine MMP-9 expression and activity, respectively.

RESULTS

Low dose curcumin (≤10 μM) did not show any obvious toxicity to the cells, while 0~10 μmol/L caused a concentration-dependent reduction in cell invasion provoked by TGF-β1. Curcumin also markedly inhibited TGF-β1-regulated MMP-9 and activation of Smad2, ERK1/2 and p38 in a dose- and time-dependent manner. Additionally, PD98059, but not SB203580, showed a similar pattern of inhibition of MMP-9 expression.

CONCLUSION

Curcumin inhibited TGF-β1-stimulated MMP-9 and the invasive phenotype in MDA-MB-231 cells, possibly associated with TGF-β/Smad and TGF-β/ERK signaling.

Destructive impact of T-lymphocytes, NK and Mast cells on basal cell layers: implications for tumor invasion

BACKGROUND

Our previous studies have suggested that the primary impact of immune cell infiltration into the normal or pre-invasive tissue component is associated with the physical destruction of epithelial capsules, which may promote tumor progression and invasion. Our current study attempted to further verify our previous observations and determine the primary type(s) of infiltrating immune cells and the possible mechanism associated with physical destructions of the epithelial capsules.

METHODS

In total, the study was conducted with 250 primary breast and prostate tumors, the primary immune cell of cytotoxic T-lymphocytes (CTL), Natural killer cells (NK) and Mast cells were analyzed by immunohistochemistry, fluorescent labeling and apoptosis assay. qRT-PCR was used for gene expression analysis. Our current study assessed the physical disruption of these immune cells and potential impact on the epithelial capsule of human breast and prostate tumors.

RESULTS

Our study yield several clinically-relevant findings that have not been studied before. (1) A vast majority of these infiltrating immune cells are distributed in the normal-appearing or pre-invasive tissue components rather than in invasive cancer tissues. (2) These cells often form rings or semilunar structures that either surround focally-disrupted basal cell layers or physically attach to the basal cells. (3) Basal cells physically associated with these immune cells generally displayed distinct signs of degeneration, including substantially elevated apoptosis, necrosis, and reduced tumor suppressor p63 expression. In contrast, luminal cells overlying focally disrupted basal cell layers had a substantially increased proliferation rate and elevated expression of stem cell markers compared to their adjacent morphologically similar counterparts that overlie a non-disrupted capsule.

CONCLUSION

Our findings suggest that at the early stage of tumor invasion, CTL, NK and Mast cells are the main types of tumor infiltrating immune cells involved in focal degenerative products in the tumor capsules. The primary impact of these infiltrating immune cells is that they are associated with focal disruptions of the tumor capsule, which selectively favor tumor stem cells proliferation and invasion.

Regulation of ROCK1 via Notch1 during breast cancer cell migration into dense matrices

Background

The behaviour of tumour cells depends on factors such as genetics and the tumour microenvironment. The latter plays a crucial role in normal mammary gland development and also in breast cancer initiation and progression. Breast cancer tissues tend to be highly desmoplastic and dense matrix as a pre-existing condition poses one of the highest risk factors for cancer development. However, matrix influence on tumour cell gene expression and behaviour such as cell migration is not fully elucidated.

Results

We generated high-density (HD) matrices that mimicked tumour collagen content of 20 mg/cm³ that were ~14-fold stiffer than low-density (LD) matrix of 1 mg/cm³. Live-cell imaging showed breast cancer cells utilizing cytoplasmic streaming and cell body contractility for migration within HD matrix. Cell migration was blocked in the presence of both the ROCK inhibitor, Y-27632, and the MMP inhibitor, GM6001, but not by the drugs individually. This suggests roles for ROCK1 and MMP in cell migration are complicated by compensatory mechanisms. ROCK1 expression and protein activity, were significantly upregulated in HD matrix but these were blocked by treatment with a histone deacetylase (HDAC) inhibitor, MS-275. In HD matrix, the inhibition of ROCK1 by MS-275 was indirect and relied upon protein synthesis and Notch1. Inhibition of Notch1 using pooled siRNA or DAPT abrogated the inhibition of ROCK1 by MS-275.

Conclusion

Increased matrix density elevates ROCK1 activity, which aids in cell migration via cell contractility. The upregulation of ROCK1 is epigenetically regulated in an indirect manner involving the repression of Notch1. This is demonstrated from inhibition of HDACs by MS-275, which caused an upregulation of Notch1 levels leading to blockade of ROCK1 expression.

In situ malignant transformation and progenitor-mediated cell budding: two different pathways for breast ductal and lobular tumor invasion

The human breast lobular and ductal structures and the derived tumors from these structures differ substantial in their morphology, microenvironment, biological presentation, functions, and clinical prognosis. Based on these differences, we have proposed that pre-invasive lobular tumors may progress to invasive lesions through "in situ malignant transformation", in which the entire myoepithelial cell layer within a given lobule or lobular clusters undergoes extensive degeneration and disruptions, which allows the entire epithelial cell population associated with these myoepithelial cell layers directly invade the stroma or vascular structures. In contrast, pre-invasive ductal tumors may invade the stroma or vascular structures through "progenitor-mediated cell budding", in which focal myoepithelial cell degeneration-induced aberrant leukocyte infiltration causes focal disruptions in the tumor capsules, which selectively favor monoclonal proliferation of the overlying tumor stem cells or a biologically more aggressive cell clone. Our current study attempted to provide more direct morphological and immunohistochemical data that are consistent with our hypotheses.

The functional role of reactive stroma in benign prostatic hyperplasia

The human prostate gland is one of the only internal organs that continue to enlarge throughout adulthood. The specific mechanisms that regulate this growth, as well as the pathological changes leading to the phenotype observed in the disease benign prostatic hyperplasia (BPH), are essentially unknown. Recent studies and their associated findings have made clear that many complex alterations occur, involving persistent and chronic inflammation, circulating hormonal level deregulation, and aberrant wound repair processes. BPH has been etiologically characterized as a progressive, albeit discontinuous, hyperplasia of both the glandular epithelial and the stromal cell compartments coordinately yielding an expansion of the prostate gland and clinical symptoms. Interestingly, the inflammatory and repair responses observed in BPH are also key components of general wound repair in post-natal tissues. These responses include altered expression of chemokines, cytokines, matrix remodeling factors, chronic inflammatory processes, altered immune surveillance and recognition, as well as the formation of a prototypical 'reactive' stroma, which is similar to that observed across various fibroplasias and malignancies of a variety of tissue sites. Stromal tissue, both embryonic mesenchyme and adult reactive stroma myofibroblasts, has been shown to exert potent and functional regulatory control over epithelial proliferation and differentiation as well as immunoresponsive modulation. Thus, the functional biology of a reactive stroma, within the context of an adult disease typified by epithelial and stromal aberrant hyperplasia, is critical to understand within the context of prostate disease and beyond. The mechanisms that regulate reactive stroma biology in BPH represent targets of opportunity for new therapeutic approaches that may extend to other tissue contexts. Accordingly, this review seeks to address the dissection of important factors, signaling pathways, genes, and other regulatory components that mediate the interplay between epithelium and stromal responses in BPH.

The myoepithelial cell layer may serve as a potential trigger factor for different outcomes of stage-matched invasive lobular and ductal breast cancers

Invasive lobular cancer (ILC) tends to be significantly larger in size with significantly more positive lymph nodes, whereas ILC has a significantly more favorable outcome, compared to stage-matched invasive ductal carcinoma (IDC). The mechanism accounting for such differences remains elusive. Based on morphological, immunohistochemical, and molecular studies of over 1,000 cases of human breast cancers, we hypothesize that the differences may result from the structural and/or functional differences of their surrounding myoepithelial cell layers, which dictate lobular and ductal tumor cells to follow different pathways of invasion or metastasis. The background, rationale, supportive data, and implications of our hypothesis are presented and discussed.

Tenascin-C may aggravate left ventricular remodeling and function after myocardial infarction in mice

Tenascin-C (TN-C) is an extracellular matrix glycoprotein with high bioactivity. It is expressed at low levels in normal adult heart, but upregulated under pathological conditions, such as myocardial infarction (MI). Recently, we (Ref. 34) reported that MI patients with high serum levels of TN-C have a greater incidence of maladaptive cardiac remodeling and a worse prognosis. We hypothesized that TN-C may aggravate left ventricular remodeling. To examine the effects of TN-C, MI was induced by ligating coronary arteries of TN-C knockout (KO) mice under anesthesia and comparing them with sibling wild-type (WT) mice. In WT+MI mice, TN-C expression was upregulated at day 1, peaked at day 5, downregulated and disappeared by day 28, and the molecule was localized in the border zone between intact myocardium and infarct lesions. The morphometrically determined infarct size and survival rate on day 28 were comparable between the WT+MI and KO+MI groups. Echocardiography and hemodynamic analyses demonstrated left ventricular end-diastolic diameter, myocardial stiffness, and left ventricular end-diastolic pressure to be significantly increased in both WT+MI and KO+MI mice compared with sham-operated mice. However, end-diastolic pressure and dimension and myocardial stiffness of KO+MI were lower than those of the WT+MI mice. Histological examination revealed normal tissue healing, but interstitial fibrosis in the residual myocardium in peri-infarcted areas was significantly less pronounced in KO+MI mice than in WT+MI mice. TN-C may thus accelerate adverse ventricular remodeling, cardiac failure, and fibrosis in the residual myocardium after MI.

MicroRNA involvement in the pathogenesis and management of breast cancer

MicroRNAs (miRNAs) are a highly abundant class of endogenous small non-coding RNAs (18-25 nucleotides in length) that regulate gene expression by targeting protein-coding mRNAs post-transcriptionally. miRNAs have been implicated in cancer development and progression. As miRNAs and their regulatory functions are further revealed, the more the importance of miRNA-directed gene regulation is emphasised. In the human genome, 695 mature miRNAs have been identified, although computational calculation predicts that this may increase to >1000. Deregulation of miRNA expression profiles is thought to be implicated in the pathogenesis of many human cancers including breast tumours. Breast cancer subtypes are observed to have deranged miRNA expression signatures, which makes miRNAs important targets for developing a novel molecular classification of breast cancer and opening avenues for more individualised treatment strategies for patients with breast cancer.

Elevated level of tenascin and matrix metalloproteinase 9 correlates with the bone destruction capacity of cholesteatomas

OBJECTIVES

Bone destruction is a key step in the progression of cholesteatomas. Some of the lesions can grow without affecting the surrounding anatomic structures, whereas others can cause severe bone destruction despite their limited size. This study aims to identify factors that could play important role during the invasion of the disease.

METHODS

Cholesteatoma tissue samples were examined immunohistochemically. Tissue samples were arranged on the basis of bone destruction (destructive cholesteatomas [DC] and nondestructive cholesteatomas [NDC]). Double-immunofluorescent labeling was performed to detect simultaneously 1) tenascin (TN) and cytokeratin; 2) matrix metalloproteinase 9 (MMP-9) and TN; 3) TN and Ki-67. An in situ apoptosis detection kit was used to detect apoptotic cells. External auditory canal skin samples were used as control.

RESULTS

1) In DCs, more widespread stromal TN labeling was seen compared with NDCs or external auditory canal skin samples. 2) More enhanced MMP-9 staining was detected in DCs compared with NDCs. 3) The proportion of Ki-67-positive cells in DC samples was significantly higher than in NDCs. 4) The percentage of apoptotic cells was higher in NDC than in DC samples.

CONCLUSION

Our present study demonstrates that levels of TN, MMP-9, and proliferative activity are increased in cholesteatomas. It has also been shown that increased levels of TN, MMP-9-positive cells, and proliferative activity of the lesions, as well as decreased levels of apoptosis, can be linked to more aggressive clinical behavior of cholesteatomas. Our findings also indicate that TN and MMP-9 can be key molecules of bone destruction during cholesteatoma progression.

Stromal matrix protein expression following preoperative systemic therapy in breast cancer

PURPOSE

Stromal alterations are observed following preoperative systemic therapy in breast cancer. The aim of the present study was to analyze the qualitative and quantitative changes of representative tumor stroma proteins in the context of neoadjuvant therapy and the response of patients undergoing preoperative systemic therapy.

EXPERIMENTAL DESIGN

Fifty women receiving preoperative systemic therapy were evaluated for clinical and pathologic parameters. Clinical response was defined according to International Union against Cancer (UICC) criteria, whereas pathologic responses to preoperative systemic therapy were defined according to the Chevallier and Sataloff classifications. The expression of tenascin-C, syndecan-1, collagen IV, and smooth muscle actin proteins was investigated using morphometric analysis of immunohistochemical reactions. Quantitative reverse transcription-PCR was done to evaluate the mRNA expression level of syndecan-1 and tenascin-C. The data were compared with 20 breast cancer samples of patients not treated with preoperative systemic therapy.

RESULTS

According to UICC criteria, the expression levels of collagen IV were up-regulated in all preoperative systemic therapy-treated patients (P = 0.002). Collagen IV was up-regulated in the preoperative systemic therapy group in both Chevallier and Sataloff classifications compared with the control cases (P = 0.025 and P = 001, respectively). There were no significant differences in the expression of smooth muscle actin between the treated and nontreated groups. The syndecan-1 proteoglycan level was significantly down-regulated in the preoperative systemic therapy group (Chevallier classes P = 0.015, Sataloff classes P = 0.015). Tenascin-C was up-regulated in women with progressive disease (P = 0.005).

CONCLUSION

We have observed that the stromal component of breast carcinomas following preoperative systemic therapy differs from the nontreated tumors, which can be evaluated with the analysis of the above mentioned proteins.

Matricellular proteins produced by melanocytes and melanomas: in search for functions

Matricellular proteins are modulators of cell-matrix interactions and cellular functions. The group includes thrombospondin, osteopontin, osteonectin/SPARC, tenascin, disintegrins, galectins and CCN proteins. The production of matricellular proteins such as osteopontin, SPARC or tenascin is highly upregulated in melanoma and other tumors but little is known about their functions in tumor growth, survival, and metastasis. The distribution pattern of CCN3 differs from most other matricellular proteins, such that it is produced abundantly by normal melanocytes, but is not significantly expressed in melanoma cells. CCN3 is known to inhibit melanocyte proliferation and stimulate adhesion to collagen type IV, the main component of the basement membrane. CCN3 has a unique role in securing adhesion of melanocytes to the basement membrane distinct from other melanoma-produced matricellular proteins which act as de-adhesive molecules and antagonists of focal adhesion. Qualitative and quantitative changes in matricellular protein expression contribute to melanoma progression similar to the E-cadherin to N-cadherin class switch, allowing melanoma cells to escape from keratinocyte control.

Breast tumor microenvironment: proteomics highlights the treatments targeting secretome

Tumor secreted substances (secretome), including extracellular matrix (ECM) components, act as mediators of tumor-host communication in the breast tumor microenvironment. Proteomic analysis has emphasized the value of the secretome as a source of prospective markers and drug targets for the treatment of breast cancers. Utilizing bioinformatics, our recent studies revealed global changes in protein expression after the activation of ECM-mediated signaling in breast cancer cells. A newly designed technique integrating a capillary ultrafiltration (CUF) probe with mass spectrometry was demonstrated to dynamically sample and identify in vivo and pure secretome from the tumor microenvironment. Such in vivo profiling of breast cancer secretomes may facilitate the development of novel drugs specifically targeting secretome.

Endogenous human microRNAs that suppress breast cancer metastasis

A search for general regulators of cancer metastasis has yielded a set of microRNAs for which expression is specifically lost as human breast cancer cells develop metastatic potential. Here we show that restoring the expression of these microRNAs in malignant cells suppresses lung and bone metastasis by human cancer cells in vivo. Of these microRNAs, miR-126 restoration reduces overall tumour growth and proliferation, whereas miR-335 inhibits metastatic cell invasion. miR-335 regulates a set of genes whose collective expression in a large cohort of human tumours is associated with risk of distal metastasis. miR-335 suppresses metastasis and migration through targeting of the progenitor cell transcription factor SOX4 and extracellular matrix component tenascin C. Expression of miR-126 and miR-335 is lost in the majority of primary breast tumours from patients who relapse, and the loss of expression of either microRNA is associated with poor distal metastasis-free survival. miR-335 and miR-126 are thus identified as metastasis suppressor microRNAs in human breast cancer.

Mechanisms of metastasis: epithelial-to-mesenchymal transition and contribution of tumor microenvironment

Every year about 500,000 people in the United States die as a result of cancer. Among them, 90% exhibit systemic disease with metastasis. Considering this high rate of incidence and mortality, it is critical to understand the mechanisms behind metastasis and identify new targets for therapy. In recent years, two broad mechanisms for metastasis have received significant attention: epithelial-to-mesenchymal transition (EMT) and tumor microenvironment interactions. EMT is believed to be a major mechanism by which cancer cells become migratory and invasive. Various cancer cells--both in vivo and in vitro--demonstrate features of epithelial-to-mesenchymal-like transition. In addition, many steps of metastasis are influenced by host contributions from the tumor microenvironment, which help determine the course and severity of metastasis. Here we evaluate the diverse mechanisms of EMT and tumor microenvironment interactions in the progression of cancer, and construct a rational argument for targeting these pathways to control metastasis.

Focal degeneration of basal cells and the resultant auto-immunoreactions: a novel mechanism for prostate tumor progression and invasion

The development of human prostate cancer is believed to be a multistep process, progressing sequentially from normal, to hyperplasia, to prostatic intraepithelial neoplasia (PIN), and to invasive and metastatic lesions. High grade PIN has been generally considered as the direct precursor of invasive lesions, and the progression of PIN is believed to be triggered primarily, if not solely, by the overproduction of proteolytic enzymes predominately by cancer cells, which result in the degradation of the basement membrane. These theories, however, are hard to reconcile with two main facts: (1) only about 30% untreated PIN progress to invasive stage, while none of the current approaches could accurately identify the specific PIN or individuals at greater risk for progression, and (2) results from recent world-wide clinical trials with a wide variety of proteolytic enzyme inhibitors have been very disappointing, casting doubt on the validity of the proteolytic enzyme theory. Since over 90% of prostate cancer-related deaths result from invasion-related illness and the incidence of PIN could be up to 16.5-25% in routine or ultrasound guided prostate biopsy, there is an urgent need to uncover the intrinsic mechanism of prostate tumor invasion. Promoted by the facts that the basal cell population is the source of several tumor suppressors and the absence of the basal cell layer is the most distinct feature of invasive lesions, our recent studies have intended to identify the early alterations of basal cell layers and their impact on tumor invasion using multidisciplinary approaches. Our studies revealed that a subset of pre-invasive tumors contained focal disruptions (the absence of basal cells resulting in a gap greater than the combined size of at least three epithelial cells) in surrounding basal cell layers. Compared to their non-disrupted counterparts, focally disrupted basal cell layers had several unique features: (1) significantly lower proliferation; (2) significantly lower p63 expression; (3) significantly higher apoptosis; and (4) significantly higher leukocyte infiltration and stromal reactions. Compared to their counterparts distant from focal disruptions or overlying non-disrupted basal cell layers, epithelial cells overlying focal basal cell layer disruptions showed the following unique features: (1) significantly higher proliferation; (2) significantly higher expression of cell cycle control-, cell growth-, and stem cell-related genes; and (3) physical continuity with adjacent invasive lesions. Together, these findings suggest that focal basal cell layer disruptions could substantially impact the molecular profile and biological presentations of the overlying epithelial cells. Based on these and other findings, we have proposed that prostate tumor invasion is triggered by a localized degeneration of aged or injured basal cells and the resultant auto-immunoreactions. Our hypothesized steps for prostate tumor invasion include the following: (1) due to inherited or environmental factors, some patients contained cell cycle control- and renewal-related defects in the basal cell population that cause elevated basal cell degenerations; (2) the degradation products of degenerated basal cells or diffusible molecules of the overlying epithelial cells attract leukocyte infiltration; (3) leukocytes discharge their digestive enzymes upon the direct physical contact, resulting in a focal disruption in the basal cell layer, which leads to several focal alterations: (a) a focal loss of tumor suppressors and paracrine inhibitory function; (b) a focal increase of the permeability for growth-required nutrients and oxygen; (c) a focal increase of growth factors; (d) direct physical contact between epithelial and stromal cells; and (e) the exposure of the overlying epithelial cells directly to the stromal tissue fluid. These alterations individually or collectively stimulate or favor a clonal proliferation and stromal invasion of tumor progenitor or stem cells. Our hypothesis differs from the traditional theories in several aspects, including the triggering factor for the initiation of tumor invasion, the stage of tumor invasion, the cellular origin of invasive lesions, the significance of immunoreactive and stromal cells, and the potential approaches for early detection, treatment, and prevention of invasion. Our hypothesis represents a novel in vivo model as to the cellular mechanism leading to prostate tumor invasion. If confirmed, it could lead to a new direction to search for more effective approaches to combat prostate cancer. It could also have an immediate impact on patient care through improved pathologic evaluation of prostate tumor biopsies. More importantly, our hypothesis might be applicable, and significantly impact the detection, treatment, and prevention of other epithelium-derived tumors.

Tenascin cytotactin epidermal growth factor-like repeat binds epidermal growth factor receptor with low affinity

Select epidermal growth factor (EGF)-like (EGFL) repeats of human tenascin cytotactin (tenascin C) can stimulate EGF receptor (EGFR) signaling, but activation requires micromolar concentrations of soluble EGFL repeats in contrast to subnanomolar concentrations of classical growth factors such as EGF. Using in silico homology modeling techniques, we generated a structure for one such repeat, the 14th EGFL repeat (Ten14). Ten14 assumes a tight EGF-like fold with truncated loops, consistent with circular dichroism studies. We generated bound structures for Ten14 with EGFR using two different approaches, resulting in two distinctly different conformations. Normal mode analysis of both structures indicated that the binding pocket of EGFR exhibits a significantly higher mobility in Ten14-EGFR complex compared to that of the EGF-EGFR complex; we hypothesized this may be attributed to loss of key high-affinity interactions within the Ten14-EGFR complex. We proved the efficacy of our in silico models by in vitro experiments. Surface plasmon resonance measurements yielded equilibrium constant K(D) of 74 microM for Ten14, approximately three orders of magnitude weaker than that of EGF. In accordance with our predicted bound models, Ten14 in monomeric form does not bind EGFR with sufficient stability so as to induce degradation of receptor, or undergo EGFR-mediated internalization over either the short (20 min) or long (48 h) term. This transient interaction with the receptor on the cell surface is in marked contrast to other EGFR ligands which cause EGFR transit through, and signaling from intracellular locales in addition to cell surface signaling.

Antitenascin-C monoclonal antibody radioimmunotherapy for malignant glioma patients

Adults with primary malignant glioma have an unacceptably poor outcome. Most of these tumors recur at or adjacent to the site of origin, which indicates that failure to eradicate local tumor growth is a major factor contributing to poor outcome. Therefore, locoregional therapies may improve local control and overall outcome for malignant glioma patients. Malignant gliomas selectively express several factors that are not present on normal CNS tissue. Regional administration of radiolabeled monoclonal antibodies targeting tumor-specific antigens expressed by malignant gliomas offers an innovative therapeutic strategy that has recently demonstrated encouraging antitumor activity and acceptable toxicity in clinical trials at a number of centers. Most studies have utilized monoclonal antibodies against tenascin-C, an extracellular matrix glycoprotein ubiquitously expressed by malignant gliomas. This review summarizes clinical trials performed using radiolabeled antitenascin-C monoclonal antibodies for malignant glioma patients to date and highlights future plans to further develop this therapeutic strategy.

Focal degeneration of aged or injured myoepithelial cells and the resultant auto-immunoreactions are trigger factors for breast tumor invasion

The development of breast cancer is believed to be a multi-step process, sequentially progressing from normal to hyperplastic, to in situ, and to invasive stages. The progression from the in situ to invasive stage is believed to be triggered primarily, if not solely, by the overproduction of proteolytic enzymes by cancer cells, which cause degradation of the basement membrane. This theory is consistent with data derived from studies with cell cultures or animal models, while results from recent worldwide clinical trials with a variety of proteolytic enzyme inhibitors have been very disappointing, casting doubt on the validity of the enzyme theory. Based on our recent studies, we propose that breast tumor invasion is triggered by the following mechanisms and events: (1) the predisposition of genetic abnormalities in ME cell replenishment-related genes or other insults results in elevated focal degeneration of ME cells in some individuals; (2) the degradation products of ME cells or diffusible molecules of epithelial cells attract infiltration of immunoreactive cells (IRC) into the affected sites; (3) the direct physical contact between IRC and degenerated ME cells results in the discharge of digestive enzymes from IRC, causing focal disruptions in the ME cell layer; (4) focal disruptions in a given ME cell layer result in a localized loss of tumor suppressors and paracrine inhibitory function, a focal increase of permeability for oxygen, nutrients, and growth factors, and a localized increase of leukocyte infiltration, which facilitate the monoclonal proliferation of tumor progenitors, forming a biologically more aggressive cell cluster overlying the disrupted ME cell layer; (5) the direct physical contact between the newly formed cell cluster and stromal cells stimulates the production of tenascin and other invasion-associated molecules that facilitate tissue remodeling, angiogenesis, and epithelial-mesenchymal transition, providing a favorable micro-environment for proliferation and invasion. Our hypothesis differs from the enzyme theory in the stage of tumor invasion, the cellular origin of invasive lesions, the significance of IRC and stromal cells, and the potential approaches for treatment and prevention. If confirmed, our hypothesis could facilitate the early detection of specific individuals at increased risk to develop invasive breast cancer. More importantly, our hypothesis may facilitate development of novel approaches, including stimulating ME cell growth, neutralizing ME cell degradation products, manipulating the types and extent of IRC infiltration, and controlling the extent of stromal reactions, to combat tumor invasion.

Deficiency of tenascin-C attenuates liver fibrosis in immune-mediated chronic hepatitis in mice

Tenascin-C (TNC), an extracellular matrix glycoprotein, is upregulated in chronic liver disease. Here, we investigated the contribution of TNC to liver fibrogenesis by comparing immune-mediated hepatitis in wild-type (WT) and TNC-null (TNKO) mice. Eight-week-old BALB/c mice received weekly intravenous injections of concanavalin A to induce hepatitis, and were sacrificed one week after the 3rd, 6th, 9th, and 12th injections. In WT livers, immunohistochemical staining revealed a gradual increase in TNC deposition. TNC mRNA levels also increased sequentially and peaked after the 9th injection. Collagen deposition, stained with picrosirius red, was significantly less intense in TNKO mice than in WT mice, and procollagen I and III transcripts were significantly upregulated in WT mice compared with TNKO mice. Inflammatory infiltrates were most prominent after the 3rd-6th injections in both groups and were less intense in TNKO mice than in WT mice. Interferon-gamma, tumour necrosis factor-alpha, and interleukin-4 mRNA levels were significantly higher in WT mice than in TNKO mice, while activated hepatic stellate cells (HSCs) and myofibroblasts, a cellular source of TNC and procollagens, were more common in WT livers. Transforming growth factor (TGF)-beta1 mRNA expression was significantly upregulated in WT mice, but not in TNKO mice. In conclusion, TNC can promote liver fibrogenesis through enhancement of inflammatory response with cytokine upregulation, HSC recruitment, and TGF-beta expression during progression of hepatitis to fibrosis.

Serial transplantation of NMU-induced rat mammary tumors: A model of human breast cancer progression

Human breast cancer is a heterogeneous disease that appears to progress from an in situ tumor to invasive cancer. Little is known about the molecular events driving this progression. Although microarray technology has helped us understand the genetic heterogeneity of breast cancer, its application to studying the transition from in situ to invasive disease is limited by the inability to follow the progression of a single patient's tumor. We previously used rat specific microarrays to show that N-methyl-N-nitrosourea induced tumors are similar to low-grade estrogen-receptor positive human breast cancer. Here, we transplanted these tumors through 5 generations of syngeneic hosts, and studied 65 resulting tumors. Most transplanted tumors gradually progressed from a noninvasive, low-grade cancer to a higher-grade invasive disease, losing p63 localization and basement membrane integrity. Invasive cancers frequently demonstrated a more mesenchymal phenotype with increased vimentin expression. Additionally, a unique transplant series is described with a phenotype similar to human basal-like breast cancer. Rat-specific Affymetrix gene arrays containing 15,866 gene probes identified genes that differentiated highly invasive tumors from those of low invasive potential. A linear regression analysis was used to find genes whose change in expression paralleled increasing invasive features independent of the transplant lineage of origin. Genes identified were assigned membership in cell adhesion, signal transduction, cell cycle and extracellular matrix groups, among others. This animal model overcomes the difficulty in studying human breast cancer progression. Our data support a gradual and continuous alteration in programs of gene expression during breast cancer invasion.

Tenascin-C induced signaling in cancer

Tenascin-C is an adhesion modulatory extracellular matrix molecule that is highly expressed in the microenvironment of most solid tumors. High tenascin-C expression reduces the prognosis of disease-free survival in patients with some cancers. The possible role of tenascin-C in tumor initiation and progression is addressed with emphasis on underlying signaling mechanisms. How tenascin-C affects malignant transformation, uncontrolled proliferation, angiogenesis, metastasis and escape from tumor immunosurveillance is summarized. Finally, we discuss how the phenotypes of tenascin-C knock-out mice may help define the roles of tenascin-C in tumorigenesis and how this knowledge could be applied to cancer therapy.

Cited2 modulates TGF-beta-mediated upregulation of MMP9

Cited (CBP/p300-interacting transactivators with glutamic acid (E)/aspartic acid (D)-rich C-terminal domain) 2, which is a CBP/p300-binding transcription co-activator without typical DNA-binding domains, has been implicated in control of cell growth and malignant transformation in Rat1 cells. In this report, we provide evidence that Cited2 is an important regulator of transforming growth factor (TGF)-beta signaling. Overexpression of Cited2 enhanced TGF-beta-mediated transcription of a Smad-Binding Element-containing luciferase reporter construct, SBE4-Luc. This may occur through a direct physical association of Cited2 with Smads 2 and 3, as supported by co-immunoprecipitation, mammalian two-hybrid and glutathione S-transferase-pull down assays. The transcription factor p300, which binds to Smad3, was shown to further enhance the interaction between Cited2 and Smad3, and the transcriptional responses of Smad3 by Cited2 in reporter assays. Cited2 enhances TGF-beta-mediated upregulation of matrix metalloproteinase 9 (MMP9) in Cited2 inducible mouse embryo fibroblasts. Overexpression of Cited2 enhanced TGF-beta-mediated MMP9 promoter reporter activity. Moreover, knockdown of Cited2 in MDA-MB-231 cells attenuated TGF-beta-mediated upregulation of MMP9 and TGF-beta-mediated cell invasion. Chromatin immunoprecipitation showed that Cited2 and Smad3 were recruited to MMP9 promoter upon TGF-beta stimulation. This is the first demonstration that Cited2 functions as a Smad3/p300-interacting transcriptional co-activator in modulating the expression of MMP9, which could affect tumor cell invasion mediated by TGF-beta.