Matrix metalloproteinase-1 promotes breast cancer angiogenesis and osteolysis in a novel in vivo model

MMP1-induced NF-κB activation promotes epithelial-mesenchymal transition and sacituzumab govitecan resistance in hormone receptor-positive breast cancer

Sacituzumab govitecan (SG), a novel antibody-drug conjugate (ADC), shows promise in the treatment of breast cancer (BC); however, drug resistance limits its clinical application. Matrix metalloproteinase 1 (MMP1), which is overexpressed in many tumor types, plays a key role in tumor metastasis and drug resistance. The involvement of MMP1 in SG resistance in metastatic hormone receptor-positive (HR + ) BC has not been previously reported. In this study, we employed various in vitro and in vivo approaches to investigate the role of MMP1 in SG resistance in BC. MMP1 expression was manipulated in different BC cell lines through lentiviral transfection and small interfering RNA techniques. Key methodologies included Western blot, quantitative reverse transcription PCR, and RNA sequencing to assess marker expression and identify differentially expressed genes. Functional assays were conducted to evaluate cell viability, proliferation, invasion, and migration. In vivo, a cell-derived xenograft model in nude mice was utilized to assess tumor growth and drug response. Bioinformatics analyses further explored MMP1 expression and its clinical relevance across different cancer types. Our findings indicate that MMP1 is overexpressed by approximately 30-fold in HR + BC tissues and is associated with poorer prognosis among HR + BC patients. Furthermore, our analysis reveals that HR + BC with high MMP1 expression displays resistance to SG, supporting the hypothesis that MMP1 plays a key role in regulating ADC resistance. Mechanistic studies demonstrate that MMP1 can activate the NF-κB pathway, which subsequently influences the epithelial-mesenchymal transition, thereby contributing to SG resistance. Ultimately, our research underscores the potential of MMP1 as a therapeutic target and biomarker, facilitating personalized treatment strategies that could enhance patient outcomes in BC therapy.

In-silico study of rosmarinic acid roles in inhibiting breast cancer progression

Background

Breast cancer is the highest cancer incidence in the world. Chemotherapy is currently one of the main breast cancer treatments besides surgery. It is capable of evolving to become resistant to chemotherapy agents. Chemotherapy also has significant side effects. Rosmarinic acid could become an anti-cancer agent candidate for the treatment of breast cancer, but its molecular mechanism is still unclear.

Aim

This study aimed to clarify the molecular mechanism of rosmarinic acid anti-breast cancer properties via an in-silico study.

Methods

Web-based screening tools such as SwissTargetPrediction, Similarity Ensemble Approach (SEA), and TargetNet were used as initial screening. From web-based screening, potential proteins that interact with rosmarinic acid could be determined. Intersected proteins from 3 web-based screenings were assessed via literature review. We found 11 intersected proteins, and 6 of 11 proteins are involved in breast cancer development and progression. Those 6 proteins are MMP-1, MMP-2, MMP-9, MMP-12, aldose reductase, and M-phase Inducer Phosphatase 2 (CDC25B). Then molecular docking using Autodock 4.6.2 was used in ligand and protein interaction simulation. Those 6 proteins were selected as macromolecules in the docking study.

Results

Based on the docking result, we found that rosmarinic acid can bind MMP-1, MMP2, MMP-9, and MMP-12 active sites. The binding profile of rosmarinic acid with aldose reductase has similarities with other confirmed inhibitors. Docking with CDC25B showed that rosmarinic acid also binds in the same place as cyclin-dependent kinases (CDKs).

Conclusion

The ability of rosmarinic acid to inhibit MMP-1, MMP-2, MMP-9, aldose reductase, and CDC25B activity may underlie how rosmarinic acid is able to inhibit the development of breast cancer.

In-situ collagen mineralization modulates metastatic properties of breast cancer cells

Bone metastasis is the leading cause of morbidity and mortality in advanced-stage breast cancer patients. While most studies focus on the cellular and genetic factors associated with breast cancer metastasis, the role of the extracellular matrix (ECM) of bone in breast cancer metastasis remains elusive. In this study, we recapitulated the bone microenvironment using in-situ mineralized collagen type-I hydrogels and utilized them to understand breast cancer metastasis. Our results indicated successful mineralization of collagen type-I based hydrogels in the presence of serum proteins, which increased as a function of time. There was no difference in the adhesion of breast cancer cells seeded on collagen and mineralized collagen surfaces. However, there was a marked reduction in cell proliferation, down-regulation of various metastatic markers, and decreased migratory phenotype with a concomitant increase in cleaved caspase-3 on mineralized collagen compared to collagen hydrogels. In conclusion, our results suggest an inverse relationship between bone mineralization and the metastatic propensity of breast cancer cells. We further speculate the role of other factors in the skeletal ecosystem for mediating preferential homing of breast cancer cells to the bone microenvironment.

Targeting Matrix Metalloproteinases and Their Inhibitors in Melanoma

Malignant melanoma is one of the most important dermatological neoplasms. The high mortality rate associated with this skin disease is primarily due to the occurrence of metastases, while the diagnosis and treatment of melanoma in its early stages has a favorable prognosis. Early detection is crucial because the success of treatment is directly related to the depth of cancerous growth. The family of matrix metalloproteinases (MMPs) plays a critical role in the initiation and progression of melanoma. Prominent MMPs, including MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and MMP-14, have been shown to significantly contribute to the development of melanoma. The tumor microenvironment, particularly the extracellular matrix (ECM), has emerged as a critical factor in modulating cancer progression. This review focuses on the role of matrix metalloproteinases and their inhibitors in ECM degradation and the subsequent progression of melanoma, as well as their potential as therapeutic targets.

Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

Ossification of the Posterior Longitudinal Ligament (OPLL) is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone, resulting in limited spinal mobility and nerve compression. Employing both bulk and single-cell RNA sequencing, we elucidate the molecular characteristics, cellular components, and their evolution during the OPLL process at a single-cell resolution, and validate these findings in clinical samples. This study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in vivo. Notably, our study identifies LOXL2 as a key regulator in this process. Through gain-and loss-of-function studies, we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament cells. It acts via the HIF1A pathway, promoting the secretion of downstream VEGFA and PDGF-BB. This function is not related to the enzymatic activity of LOXL2. Furthermore, we identify sorafenib, a broad-spectrum tyrosine kinase inhibitor, as an effective suppressor of LOXL2-mediated vascular morphogenesis. By disrupting the coupling between vascularization and osteogenesis, sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone mass. These findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

Comparison between a novel salivary marker and several clinical prognosticators in oral cavity cancer

Objectives

This study aimed to investigate the association between salivary matrix metalloproteinase-1 (MMP-1) and clinicopathological parameters of oral cavity squamous cell carcinoma (OSCC) and compare the prognostic efficacy of salivary MMP-1 and other established circulating markers for OSCC.

Methods

Saliva specimens from 479 OSCC subjects were examined using an enzyme-linked immunosorbent assay. The area under the curve (AUC) values of salivary MMP-1 and other markers were calculated, and survival analyses were conducted using Kaplan-Meier and multivariate regression methods.

Results

Salivary MMP-1 showed good discrimination in predicting overall survival, with an AUC of 0.638, which was significantly higher than that of albumin (0.530, p = .021) and Charlson comorbidity index (0.568, p = .048) and comparable with neutrophil-to-lymphocyte ratio (0.620, p = .987), platelet-to-lymphocyte ratio (0.575, p = .125), and squamous cell carcinoma antigen (0.609, p = .605). Elevated levels of salivary MMP-1 were significantly associated with higher pT classification, pN classification, overall pathological stage, positive extranodal extension, tumor differentiation, positive lymphovascular invasion, positive perineural invasion, and tumor depth (p all <.05). Multivariate analyses indicated that a higher level of salivary MMP-1 (≥2060.0 pg/mL) was an independent predictive factor of poorer overall survival (adjusted hazard ratio: 1.421 [95% confidential interval: 1.014-1.989], p = .041).

Conclusion

The study found that the salivary MMP-1 level was significantly associated with many adverse clinicopathological parameters of OSCC. In OSCC, it was found to have superior efficacy in predicting prognosis and was an independent prognostic factor of post-treatment outcome.

Level of evidence

3.

Weaving the nest: extracellular matrix roles in pre-metastatic niche formation

The discovery that primary tumors condition distant organ sites of future metastasis for seeding by disseminating tumor cells through a process described as the pre-metastatic niche (PMN) formation revolutionized our understanding of cancer progression and opened new avenues for therapeutic interventions. Given the inherent inefficiency of metastasis, PMN generation is crucial to ensure the survival of rare tumor cells in the otherwise hostile environments of metastatic organs. Early on, it was recognized that preparing the "soil" of the distal organ to support the outgrowth of metastatic cells is the initiating event in PMN development, achieved through the remodeling of the organ's extracellular matrix (ECM). Remote restructuring of ECM at future sites of metastasis under the influence of primary tumor-secreted factors is an iterative process orchestrated through the crosstalk between resident stromal cells, such as fibroblasts, epithelial and endothelial cells, and recruited innate immune cells. In this review, we will explore the ECM changes, cellular effectors, and the mechanisms of ECM remodeling throughout PMN progression, as well as its impact on shaping the PMN and ultimately promoting metastasis. Moreover, we highlight the clinical and translational implications of PMN ECM changes and opportunities for therapeutically targeting the ECM to hinder PMN formation.

miRNA-130 Promotes Migration and Angiogenesis of Endothelial Progenitor Cells Through PI3K/AKT/mTOR Pathways

<sec> <title>Aim:</title> In this study, we aimed to investigate the effects and mechanisms of miRNA-130a in human endothelial progenitor cells (EPCs) involved in Deep vein thrombosis (DVT). </sec> <sec> <title>Methods:</title> EPCs were isolated and identified by cell morphology and surface marker detection. The effect of miR-130a on the migration, invasion and angiogenesis of EPCs in vitro were also detected. In addition, whether miR-130a is involved in the MMP-1 expression and Akt/PI3K/mTOR signaling pathway was also demonstrated. </sec> <sec> <title>Results:</title> Results suggested that miRNA-130a promotes migration, invasion, and tube formation of EPCs by positively regulating the expression of MMP-1 through Akt/PI3K/mTOR signaling pathway. </sec> <sec> <title>Conclusion:</title> Thus, as a potential therapeutic target, miRNA-130a may play an important role in the treatment of DVT. </sec>

Breast Cancer Cells Metastasize to the Tissue-Engineered Premetastatic Niche by Using an Osteoid-Formed Polycaprolactone/Nanohydroxyapatite Scaffold

It has been deemed that the premetastatic niche (PMN) plays a critical role in facilitating bone metastasis of breast cancer cells. Tissue engineering scaffolds provide an advantageous environment to promote osteogenesis that may mimic the bony premetastatic niches (BPMNs). In this study, human mesenchymal stem cells (hMSCs) were seeded onto designed polycaprolactone/nanohydroxyapatite (PCL-nHA) scaffolds for osteogenic differentiation. Subsequently, a coculture system was used to establish the tissue-engineered BPMNs by culturing breast cancer cells, hMSCs, and osteoid-formed PCL-nHA scaffolds. Afterwards, a migration assay was used to investigate the recruitment of MDA-MB-231, MCF-7, and MDA-MB-453 cells to the BPMNs' supernatants. The cancer stem cell (CSC) properties of these migrated cells were investigated by flow cytometry. Our results showed that the mRNA expression levels of alkaline phosphatase (ALP), Osterix, runt-related transcription factor 2 (Runx2), and collagen type I alpha 1 (COL1A1) on the PCL-nHA scaffolds were dramatically increased compared to the PCL scaffolds on days 11, 18, and 32. The expression of CXCL12 in these BPMNs was increased gradually over coculturing time, and it may be a feasible marker for BPMNs. Furthermore, migration analysis results showed that the higher maturation of BPMNs collectively contributed to the creation of a more favorable niched site for the cancerous invasion. The subpopulation of breast cancer stem cells (BCSCs) was more likely to migrate to fertile BPMNs. The proportion of BCSCs in metastatic MDA-MB-231, MCF-7, and MDA-MB-453 cells were increased by approximately 63.47%, 149.48%, and 127.60%. The current study demonstrated that a designed tissue engineering scaffold can provide a novel method to create a bone-mimicking environment that serves as a useable platform to recapitulate the BPMNs and help interrogate the scheme of bone metastasis by breast cancer.

The In Vivo Selection Method in Breast Cancer Metastasis

Metastasis is a complex event in cancer progression and causes most deaths from cancer. Repeated transplantation of metastatic cancer cells derived from transplanted murine organs can be used to select the population of highly metastatic cancer cells; this method is called as in vivo selection. The in vivo selection method and highly metastatic cancer cell lines have contributed to reveal the molecular mechanisms of cancer metastasis. Here, we present an overview of the methodology for the in vivo selection method. Recent comparative analysis of the transplantation methods for metastasis have revealed the divergence of metastasis gene signatures. Even cancer cells that metastasize to the same organ show various metastatic cascades and gene expression patterns by changing the transplantation method for the in vivo selection. These findings suggest that the selection of metastasis models for the study of metastasis gene signatures has the potential to influence research results. The study of novel gene signatures that are identified from novel highly metastatic cell lines and patient-derived xenografts (PDXs) will be helpful for understanding the novel mechanisms of metastasis.

Artemin promotes oncogenicity, metastasis and drug resistance in cancer cells

Artemin (ARTN) is a member of glial cell line-derived neurotrophic factor (GDNF) family of ligands, and its signaling is mediated via a multi-component receptor complex including the glycosylphosphatidylinositol-anchored GDNF family receptors a (GFRa1, GFRa3) and RET receptor tyrosine kinase. The major mechanism of ARTN action is via binding to a non-signaling co-receptor. The major function of ARTN is to drive the molecule to induce migration and axonal projection from sympathetic neurons. It also promotes the survival, proliferation and neurite outgrowth of sympathetic neurons in vitro. ARTN triggers oncogenicity and metastasis by the activation of the AKT signaling pathway. Recent studies have reported that the expression of ARTN in hepatocellular carcinoma is associated with increased tumor size, quick relapse and shorter survival. Furthermore, ARTN promotes drug resistance such as antiestrogens, doxorubicin, fulvestrant, paclitaxel, tamoxifen and trastuzumab. Moreover, ARTN also stimulates the radio-therapeutic resistance. This review highlights the proposed roles of ARTN in cancer cells and discusses recent results supporting its emerging role as an oncogenic, metastatic and drug-resisting agent with a special focus on how these new insights may facilitate rational development of ARTN for targeted therapies in the future.

MiR-361-5p inhibits glycolytic metabolism, proliferation and invasion of breast cancer by targeting FGFR1 and MMP-1

Background

MicroRNAs function as key regulators in various human cancers, including breast cancer (BC). MiR-361-5p has been proved to be a tumor suppressor in colorectal cancer and gastric cancer in our previous study. In this study, we aim to find out the function of miR-361-5p in breast cancer progression and elaborate the mechanism that miR-361-5p acts its function in breast cancer.

Methods and results

Here we reported that miR-361-5p was down-regulated in breast cancer tissue compared with normal breast tissue and the expression of miR-361-5p was positively associated with prognosis in BC patients. Functional studies showed that overexpression of miR-361-5p suppressed the proliferation, invasion and metastasis of breast cancer cells both in vivo and in vitro. Mechanistically, we found that miR-361-5p inhibited the proliferation of BC cells by suppressing glycolysis. FGFR1, a promoter of glycolysis-related enzyme, was identified as the target of miR-361-5p that promoted glycolysis and repressed oxidative phosphorylation. Furthermore, we demonstrated that miR-361-5p inhibited breast cancer cells invasion and metastasis by targeting MMP-1. An inverse expression pattern was also found between miR-361-5p and FGFR1 or MMP-1 in a cohort of 60 BC tissues.

Conclusion

Our results indicate that miR-361-5p inhibits breast cancer cells glycolysis and invasion by respectively repressing FGFR1 and MMP-1, suggesting that miR-361-5p and its targets may serve as therapeutic targets in breast cancer treatment.

MMP-1 and MMP-8 expression in giant-cell fibroma and inflammatory fibrous hyperplasia

The aim of this study is to compare the immunoexpression of metalloproteinases 1 and 8 in giant-cell fibroma, inflammatory fibrous hyperplasia and normal mucosa. Twenty-two cases of giant-cell fibroma, inflammatory fibrous hyperplasia and oral mucosa (control) each were subjected to immunohistochemistry using anti-metalloproteinase-1 and anti-metalloproteinase-8 antibodies. Eight images of each case were captured and analysed through the a) application of a count grid to count the number of positive neutrophils, macrophages, lymphocytes, plasma cells, fibroblasts and blood vessels to obtain the percentage of staining and b) semi-automated segmentation quantifying the stained area in square micrometres. Statistical tests included ANOVA Two-way, Kruskal Wallis and Games-Howell, with a significance level of 5%. An increased percentage of metalloproteinase-1-immunopositive blood vessels were observed in giant-cell fibroma (26.6±22.4; p=0.02) and inflammatory fibrous hyperplasia (34.3±31.5; p=0.01) compared with the control group (19.6±9.2). No significant differences in inflammatory cells, fibroblasts and total area of metalloproteinase-1 and -8 were noted among the three groups. Metalloproteinase-1 apparently acts within the pathogenesis of giant-cell fibroma and inflammatory fibrous hyperplasia.

What Is Breast in the Bone?

The normal developmental program that prolactin generates in the mammary gland is usurped in the cancerous process and can be used out of its normal cellular context at a site of secondary metastasis. Prolactin is a pleiotropic peptide hormone and cytokine that is secreted from the pituitary gland, as well as from normal and cancerous breast cells. Experimental and epidemiologic data suggest that prolactin is associated with mammary gland development, and also the increased risk of breast tumors and metastatic disease in postmenopausal women. Breast cancer spreads to the bone in approximately 70% of cases with advanced breast cancer. Despite treatment, new bone metastases will still occur in 30%–50% of patients. Only 20% of patients with bone metastases survive five years after the diagnosis of bone metastasis. The breast cancer cells in the bone microenvironment release soluble factors that engage osteoclasts and/or osteoblasts and result in bone breakdown. The breakdown of the bone matrix, in turn, enhances the proliferation of the cancer cells, creating a vicious cycle. Recently, it was shown that prolactin accelerated the breast cancer cell-mediated osteoclast differentiation and bone breakdown by the regulation of breast cancer-secreted proteins. Interestingly, prolactin has the potential to affect multiple proteins that are involved in both breast development and likely bone metastasis, as well. Prolactin has normal bone homeostatic roles and, combined with the natural “recycling” of proteins in different tissues that can be used for breast development and function, or in bone function, increases the impact of prolactin signaling in breast cancer bone metastases. Thus, this review will focus on the role of prolactin in breast development, bone homeostasis and in breast cancer to bone metastases, covering the molecular aspects of the vicious cycle.

Upregulation of Thrombin/Matrix Metalloproteinase-1/Protease-Activated Receptor-1 Chain in Proliferative Diabetic Retinopathy

PURPOSE

Selective proteolytic activation of protease-activated receptor-1 (PAR1) by thrombin and matrix metalloproteinase-1 (MMP-1) plays a central role in enhancing angiogenesis. We investigated the expression levels of thrombin, MMP-1, and PAR1 and correlated these levels with vascular endothelial growth factor (VEGF) in proliferative diabetic retinopathy (PDR). In addition, we examined the expression of PAR1 and thrombin in the retinas of diabetic rats and PAR1 in human retinal microvascular endothelial cells (HRMEC) following exposure to high-glucose, the proinflammatory cytokines interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and the hypoxia mimetic agent cobalt chloride (CoCl₂).

METHODS

Vitreous samples from 32 PDR and 23 nondiabetic patients, epiretinal membranes from 10 patients with PDR, retinas of rats, and HRMEC were studied by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and Western blot analysis. An assay for in vitro cell migration angiogenesis was performed in HRMEC.

RESULTS

In epiretinal membranes, PAR1 was expressed in vascular endothelial cells, CD45-expressing leukocytes, and myofibroblasts. ELISA and Western blot assays revealed significant increases in the expression levels of thrombin, MMP-1, and VEGF in vitreous samples from PDR patients compared to nondiabetic controls. Significant positive correlations were found between the levels of VEGF and the levels of thrombin (r = 0.41; p = 0.006) and MMP-1 (r = 0.66; p < 0.0001). Significant increases of cleaved PAR1 (approximately 50 kDa) and the proteolytically active thrombin (approximately 50 kDa) were detected in rat retinas after induction of diabetes. The proinflammatory cytokines IL-1β and TNF-α, but not high-glucose and CoCl₂, induced upregulation of cleaved PAR1 (approximately 30 kDa) in HRMEC. In addition, thrombin and MMP-1 induced VEGF in HRMEC and vorapaxar, a PAR1 inhibitor, inhibited thrombin-induced migration in HRMEC.

CONCLUSIONS

Interactions among thrombin, MMP-1, PAR1, and VEGF might facilitate angiogenesis in PDR.

Imaging Matrix Metalloproteinase Activity Implicated in Breast Cancer Progression

Proteolysis has been cited as an important contributor to cancer initiation and progression. One can take advantage of tumor-associated proteases to selectively deliver imaging agents. Protease-activated imaging systems have been developed using substrates designed for hydrolysis by members of the matrix metalloproteinase (MMP) family. We presently describe approaches by which one can optically image matrix metalloproteinase activity implicated in breast cancer progression, with consideration of selective versus broad protease probes.

Different Preference of Degradome in Invasion versus Angiogenesis

Proteases are required for a multitude of cellular processes including homeostatic tissue remodelling, invasion and angiogenesis. The physiological function of a cell or tissue is reflected by the set of proteases expressed, also termed degradome. The role of proteases in invasion and angiogenesis has been studied intensively, mostly in cancer. We aimed to compare the set of proteases required for physiological invasion versus physiological angiogenesis from cells deriving from the same organ, and to identify the proteases specific for each process. The human placenta comprises trophoblasts that invade the maternal uterus in a regulated, physiological manner, and it is the source of primary endothelial cells. We isolated the trophoblasts and endothelial cells and verified their invasive phenotype and angiogenic properties, respectively. We then performed gene expression analysis of the degradome, e.g. cysteine, metallo, serine, threonine and aspartic proteases, identified the differentially expressed proteases among the trophoblasts and endothelial cells, and clustered them hierarchically. The results revealed that the set of proteases in trophoblasts versus in endothelial cells overlaps, with a total of 69% in common. Nevertheless, 42% of the studied degradomes differed, with a fold change ≥2. For instance, metalloproteinases were predominantly expressed in trophoblasts, and 31% of the proteases were exclusively expressed in either trophoblasts or endothelial cells; this suggests particular roles for these proteases in either invasion or angiogenesis. Our data identify common and distinct proteases in cells capable of performing invasion and angiogenesis, and may provide basic information for the design of techniques to specifically investigate invasion or angiogenesis.

A new prodrug form of Affibody molecules (pro-Affibody) is selectively activated by cancer-associated proteases

Affinity proteins have advanced the field of targeted therapeutics due to their generally higher specificity compared to small molecular compounds. However, side effects caused by on-target binding in healthy tissues are still an issue. Here, we design and investigate a prodrug strategy for improving tissue specificity of Affibody molecules in future in vivo studies. The prodrug Affibody (pro-Affibody) against the HER2 receptor was constructed by fusing a HER2-specific Affibody (ZHER2) to an anti-idiotypic Affibody (anti-ZHER2). The linker was engineered to comprise a substrate peptide for the cancer-associated matrix metalloprotease 1 (MMP-1). The hypothesis was that the binding surface of ZHER2 would thereby be blocked from interacting with HER2 until the substrate peptide was specifically hydrolyzed by MMP-1. Binding should thereby only occur where MMP-1 is overexpressed, potentially decreasing on-target toxicities in normal tissues. The pro-Affibody was engineered to find a suitable linker and substrate peptide, and the different constructs were evaluated with a new bacterial display assay. HER2-binding of the pro-Affibody was efficiently masked and proteolytic activation of the best variant yielded over 1,000-fold increase in apparent binding affinity. Biosensor analysis revealed that blocking of the pro-Affibody primarily affected the association phase. In a cell-binding assay, the activated pro-Affibody targeted native HER2 on cancer cells as opposed to the non-activated pro-Affibody. We believe this prodrug approach with proteolytic activation is promising for improving tissue specificity in future in vivo targeting applications and can hopefully be extended to other Affibody molecules and similar affinity proteins as well.

Cancer progression by breast tumors with Pit-1-overexpression is blocked by inhibition of metalloproteinase (MMP)-13

Introduction

The POU class 1 homeobox 1 transcription factor (POU1F1, also known as Pit-1) is expressed in the mammary gland and its overexpression induces profound phenotypic changes in proteins involved in cell proliferation, apoptosis, and invasion. Patients with breast cancer and elevated expression of Pit-1 show a positive correlation with the occurrence of distant metastasis. In this study we evaluate the relationship between Pit-1 and two collagenases: matrix metalloproteinase-1 (MMP-1) and matrix metalloproteinase-13 (MMP-13), which have been related to metastasis in breast cancer.

Methods

We began by transfecting the MCF-7 and MDA-MB-231 human breast adenocarcinoma cell lines with the Pit-1 overexpression vector (pRSV-hPit-1). Afterward, the mRNA, protein, and transcriptional regulation of both MMP-1 and MMP-13 were evaluated by real-time PCR, Western blot, chromatin immunoprecipitation (ChIP), and luciferase reporter assays. We also evaluated Pit-1 overexpression with MMP-1 and MMP-13 knockdown in a severe combined immunodeficiency (SCID) mouse tumor xenograft model. Finally, by immunohistochemistry we correlated Pit-1 with MMP-1 and MMP-13 protein expression in 110 human breast tumors samples.

Results

Our data show that Pit-1 increases mRNA and protein of both MMP-1 and MMP-13 through direct transcriptional regulation. In SCID mice, knockdown of MMP-13 completely blocked lung metastasis in Pit-1-overexpressing MCF-7 cells injected into the mammary fat pad. In breast cancer patients, expression of Pit-1 was found to be positively correlated with the presence of both MMP-1 and MMP-13.

Conclusions

Our data indicates that Pit-1 regulates MMP-1 and MMP-13, and that inhibition of MMP-13 blocked invasiveness to lung in Pit-1-overexpressed breast cancer cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0505-8) contains supplementary material, which is available to authorized users.

Plasma matrix metalloproteinase 1, 3, and 7 levels and breast cancer risk in the Nurses' Health study

PURPOSE

Matrix metalloproteinases (MMPs), in particular MMP1, 3, and 7, are believed to be critical to breast cancer invasion and metastasis and also may have important functions earlier in breast carcinogenesis. However, the relationship between circulating levels of MMP1, 3, and 7 and breast cancer risk is uncertain.

METHODS

We examined associations between plasma MMP1, 3, and 7 and breast cancer risk in a prospective case-control study nested within the Nurses' Health Study. Blood samples were collected from 801 cases who developed breast cancer between 1992 and 2000 and 801 matched controls, and MMP levels were measured via immunofluorescence assay.

RESULTS

No overall association was observed between any of these MMPs and breast cancer risk [top vs. bottom quintile; MMP1: odds ratio (OR) 0.9; 95 % confidence interval (CI) 0.7, 1.3; p-trend = 0.51; MMP3: OR 1.1; 95 % CI 0.8, 1.5; p-trend = 0.88; MMP7: OR = 1.2; 95 % CI 0.8, 1.7; p-trend = 0.18]. Further, findings did not significantly vary by time since blood draw, body mass index, or postmenopausal hormone use, or by breast cancer subtypes.

CONCLUSIONS

Circulating MMP1, 3, and 7 levels do not appear to be predictive of overall breast cancer risk.

RANKL/RANK/MMP-1 molecular triad contributes to the metastatic phenotype of breast and prostate cancer cells in vitro

The osteolytic nature of bone metastasis results from a tumor-driven increased bone resorption. Bone remodeling is orchestrated by the molecular triad RANK-RANKL-OPG. This process is dysregulated in bone metastases, mostly via induction of RANKL by tumor-derived factors. These factors increase expression of RANKL, which induce osteoclast formation, function, and survival, thereby increasing bone resorption. RANK is unexpectedly expressed by cancer cells, and the activation of RANKL-RANK pathway correlates with an increased invasive phenotype. To investigate the interaction between RANK expression in human breast and prostate cancer cells and their pro-metastatic phenotype we analyzed the activation of RANKL-RANK pathway and its effects on cell migration, invasion, gene expression in vitro, and osteolysis-inducing ability in vivo. RANKL activates kinase signaling pathways, stimulates cell migration, increases cell invasion, and up-regulates MMP-1 expression. In vivo, MMP-1 knockdown resulted in smaller x-ray osteolytic lesions and osteoclastogenesis, and decreased tumor burden. Therefore, RANKL inhibition in bone metastatic disease may decrease the levels of the osteoclastogenesis inducer MMP-1, contributing to a better clinical outcome.

The role of MMP-1 in breast cancer growth and metastasis to the brain in a xenograft model

Background

Brain metastasis is an increasingly common complication for breast cancer patients; approximately 15– 30% of breast cancer patients develop brain metastasis. However, relatively little is known about how these metastases form, and what phenotypes are characteristic of cells with brain metastasizing potential. In this study, we show that the targeted knockdown of MMP-1 in breast cancer cells with enhanced brain metastatic ability not only reduced primary tumor growth, but also significantly inhibited brain metastasis.

Methods

Two variants of the MDA-MB-231 human breast cancer cell line selected for enhanced ability to form brain metastases in nude mice (231-BR and 231-BR3 cells) were found to express high levels of matrix metalloproteinase-1 (MMP-1). Short hairpin RNA-mediated stable knockdown of MMP-1 in 231-BR and 231-BR3 cells were established to analyze tumorigenic ability and metastatic ability.

Results

Short hairpin RNA-mediated stable knockdown of MMP-1 inhibited the invasive ability of MDA-MB 231 variant cells in vitro, and inhibited breast cancer growth when the cells were injected into the mammary fat pad of nude mice. Reduction of MMP-1 expression significantly attenuated brain metastasis and lung metastasis formation following injection of cells into the left ventricle of the heart and tail vein, respectively. There were significantly fewer proliferating cells in brain metastases of cells with reduced MMP-1 expression. Furthermore, reduced MMP-1 expression was associated with decreased TGFα release and phospho-EGFR expression in 231-BR and BR3 cells.

Conclusions

Our results show that elevated expression of MMP-1 can promote the local growth and the formation of brain metastases by breast cancer cells.

Skeletal-related events and clinical outcomes in patients with bone metastases and normal levels of osteolysis: exploratory analyses

AIMS

High levels of bone resorption markers (e.g. N-telopeptide of type I collagen; NTX) have been correlated with increased risks of skeletal-related events and death in patients with bone metastases from solid tumours. However, the disease course has not been well characterised in patients with bone metastases but normal NTX levels. Therefore, the aim of this study was to evaluate the patterns of skeletal morbidity in patients with normal NTX levels.

MATERIALS AND METHODS

Exploratory analyses were carried out on patients with bone metastases from breast cancer, castration-resistant prostate cancer, non-small cell lung cancer or other solid tumours treated with zoledronic acid (ZOL) in phase III trials. The effects of covariates on the relative risk of death were estimated using the Cox proportional hazard model. The prognostic values of covariates were compared between patients with normal (<64 nmol/mmol creatinine) versus elevated (≥64 nmol/mmol creatinine) NTX levels.

RESULTS

Among patients with normal baseline NTX (n = 501), less than 10% developed elevated NTX levels before a skeletal-related event or death during ZOL treatment over 12 months. The prognostic factors identified in these analyses were mostly similar across NTX groups. However, some indicators of aggressive disease (e.g. visceral/cerebral metastases from breast cancer) were associated with poor clinical outcomes only in the normal NTX group.

CONCLUSIONS

Skeletal-related events were generally not preceded or followed by transition to elevated NTX in patients treated with ZOL. Elevated baseline NTX and aggressive extraskeletal disease were independently associated with reduced survival.

Matrix Metalloproteinase 1 promotes tumor formation and lung metastasis in an intratibial injection osteosarcoma mouse model

Proteolytic degradation of the extracellular matrix (ECM) is an important process during tumor invasion. Matrix Metalloproteinase 1 (MMP-1) is one of the proteases that degrade collagen type I, a major component of bone ECM. In the present study, the biological relevance of MMP-1 in osteosarcoma (OS) tumor growth and metastasis was investigated in vitro and in vivo. Human OS cells in primary culture expressed MMP-1 encoding mRNA at considerably higher levels than normal human bone cells. In addition, MMP-1 mRNA and protein expression in the highly metastatic human osteosarcoma 143-B cell line was remarkably higher than in the non-metastatic parental HOS cell line. Stable shRNA-mediated downregulation of MMP-1 in 143-B cells impaired adhesion to collagen I and anchorage-independent growth, reflected by a reduced ability to grow in soft agar. Upon intratibial injection into SCID mice, 143-B cells with shRNA-downregulated MMP-1 expression formed smaller primary tumors and significantly lower numbers of lung micro- and macrometastases than control cells. Conversely, HOS cells stably overexpressing MMP-1 showed an enhanced adhesion capability to collagen I and accelerated anchorage-independent growth compared to empty vector-transduced control cells. Furthermore, and most importantly, individual MMP-1 overexpression in HOS cells enabled the formation of osteolytic primary tumors and lung metastasis while the HOS control cells did not develop any tumors or metastases after intratibial injection. The findings of the present study reveal an important role of MMP-1 in OS primary tumor and metastasis formation to the lung, the major organ of OS metastasis.

ARTEMIN promotes de novo angiogenesis in ER negative mammary carcinoma through activation of TWIST1-VEGF-A signalling

The neurotrophic factor ARTEMIN (ARTN) has been reported to possess a role in mammary carcinoma progression and metastasis. Herein, we report that ARTN modulates endothelial cell behaviour and promotes angiogenesis in ER-mammary carcinoma (ER-MC). Human microvascular endothelial cells (HMEC-1) do not express ARTN but respond to exogenously added, and paracrine ARTN secreted by ER-MC cells. ARTN promoted endothelial cell proliferation, migration, invasion and 3D matrigel tube formation. Angiogenic behaviour promoted by ARTN secreted by ER-MC cells was mediated by AKT with resultant increased TWIST1 and subsequently VEGF-A expression. In a patient cohort of ER-MC, ARTN positively correlated with VEGF-A expression as measured by Spearman’s rank correlation analysis. In xenograft experiments, ER-MC cells with forced expression of ARTN produced tumors with increased VEGF-A expression and increased microvessel density (CD31 and CD34) compared to tumors formed by control cells. Functional inhibition of ARTN by siRNA decreased the angiogenic effects of ER-MC cells. Bevacizumab (a humanized monoclonal anti-VEGF-A antibody) partially inhibited the ARTN mediated angiogenic effects of ER-MC cells and combined inhibition of ARTN and VEGF-A by the same resulted in further significant decrease in the angiogenic effects of ER-MC cells. Thus, ARTN stimulates de novo tumor angiogenesis mediated in part by VEGF-A. ARTN therefore co-ordinately regulates multiple aspects of tumor growth and metastasis.

FH535 inhibited migration and growth of breast cancer cells

There is substantial evidence indicating that the WNT signaling pathway is activated in various cancer cell types including breast cancer. Previous studies reported that FH535, a small molecule inhibitor of the WNT signaling pathway, decreased growth of cancer cells but not normal fibroblasts, suggesting this pathway plays a role in tumor progression and metastasis. In this study, we tested FH535 as a potential inhibitor for malignant phenotypes of breast cancer cells including migration, invasion, and growth. FH535 significantly inhibited growth, migration, and invasion of triple negative (TN) breast cancer cell lines (MDA-MB231 and HCC38) in vitro. We demonstrate that FH535 was a potent growth inhibitor for TN breast cancer cell lines (HCC38 and MDA-MB-231) but not for other, non-TN breast cancer cell lines (MCF-7, T47D or SK-Br3) when cultured in three dimensional (3D) type I collagen gels. Western blotting analyses suggest that treatment of MDA-MB-231 cells with FH535 markedly inhibited the expression of NEDD9 but not activations of FAK, Src, or downstream targets such as p38 and Erk1/2. We demonstrated that NEDD9 was specifically associated with CSPG4 but not with β1 integrin or CD44 in MDA-MB-231 cells. Analyses of gene expression profiles in breast cancer tissues suggest that CSPG4 expression is higher in Basal-type breast cancers, many of which are TN, than any other subtypes. These results suggest not only a mechanism for migration and invasion involving the canonical WNT-signaling pathways but also novel strategies for treating patients who develop TN breast cancer.

Increased osteocyte death in multiple myeloma patients: role in myeloma-induced osteoclast formation

The involvement of osteocytes in multiple myeloma (MM)-induced osteoclast (OCL) formation and bone lesions is still unknown. Osteocytes regulate bone remodelling at least partially, as a result of their cell death triggering OCL recruitment. In this study, we found that the number of viable osteocytes was significantly smaller in MM patients than in healthy controls, and negatively correlated with the number of OCLs. Moreover, the MM patients with bone lesions had a significantly smaller number of viable osteocytes than those without, partly because of increased apoptosis. These findings were further confirmed by ultrastructural in vitro analyses of human preosteocyte cells cocultured with MM cells, which showed that MM cells increased preosteocyte death and apoptosis. A micro-array analysis showed that MM cells affect the transcriptional profiles of preosteocytes by upregulating the production of osteoclastogenic cytokines such as interleukin (IL)-11, and increasing their pro-osteoclastogenic properties. Finally, the osteocyte expression of IL-11 was higher in the MM patients with than in those without bone lesions. Our data suggest that MM patients are characterized by a reduced number of viable osteocytes related to the presence of bone lesions, and that this is involved in MM-induced OCL formation.

A functional polymorphism (-1607 1G→2G) in the matrix metalloproteinase-1 promoter is associated with development and progression of lung cancer

BACKGROUND

Matrix metalloproteinase-1 (MMP-1), an interstitial collagenase, plays an important role in the breakdown of extracellular matrix and mediates pathways of apoptosis, angiogenesis, and immunity. It has been demonstrated that the overexpression of this enzyme is associated with tumor initiation, invasion, and metastasis. The -1607 single guanine (1G)-to-2G polymorphism (reference single nucleotide polymorphism 1799750) in the MMP-1 promoter region creates an E26 (Ets) binding site and results in transcriptional up-regulation. The authors hypothesized that this MMP-1 polymorphism may affect susceptibility to the development and progression of cancer.

METHODS

The authors investigated their hypothesis in a lung cancer case-control study. Genotypes were analyzed in 825 patients with lung cancer and in 825 controls. Odds ratios were estimated by multivariate logistic regression, and a meta-analysis also was conducted to verify the findings.

RESULTS

Patients who had the MMP-1 2G/2G genotype had a 1.71-fold increased risk of lung cancer (95% confidence interval, 1.22-fold to 2.41-fold increased risk) compared with patients who had the 1G/1G genotype. Moreover, when patients with stage I disease were considered as a reference group, patients who carried the 2G/2G genotype had a significantly increased risk of invasive disease (stage III-IV: odds ratio, 2.02; 95% confidence interval, 1.09-3.74) compared with patients who had the 1G/1G genotype. Pooled results from the meta-analysis confirmed that those who had the 2G/2G genotype had a significantly increased risk of lung cancer compared with those who had the 1G/1G genotype, consistent with the case-control findings.

CONCLUSIONS

The current study demonstrated that the MMP-1 -1607 1G-to-2G polymorphism is associated with susceptibility to both development and progression of lung cancer.

MMP-1 expression has an independent prognostic value in breast cancer

Background

Breast cancer consists of a variety of tumours, which differ by their morphological features, molecular characteristics and outcome. Well-known prognostic factors, e.g. tumour grade and size, Ki-67, hormone receptor status, HER2 expression, lymph node status and patient age have been traditionally related to prognosis. Although the conventional prognostic markers are reliable in general, better markers to predict the outcome of an individual tumour are needed.

Matrix metalloproteinase-1 (MMP-1) expression has been reported to inversely correlate with survival in advanced cancers. In breast cancer MMP-1 is often upregulated, especially in basal-type breast tumours. The purpose of this retrospective study was to analyse MMP-1 expression in breast cancer cells and in cancer associated stromal cells and to correlate the results with traditional prognostic factors including p53 and bcl-2, as well as to patient survival in breast cancer subtypes.

Methods

Immunohistochemical analysis of MMP-1, ER, PR, Ki-67, HER2, bcl-2, p53 and CK5/6 expression was performed on 125 breast cancers. Statistical analyses were carried out using Kruskal-Wallis and Mann-Whitney -tests. In pairwise comparison Bonferroni-adjustment was applied. Correlations were calculated using Spearman rank-order correlation coefficients. Kaplan-Meier survival analyses were carried out to compare breast cancer-specific survival curves. Factors significantly associated with disease-specific survival in univariate models were included in multivariate stepwise.

Results

Positive correlations were found between tumour grade and MMP-1 expression in tumour cells and in stromal cells. P53 positivity significantly correlated with MMP-1 expression in tumour cells, whereas HER2 expression correlated with MMP-1 both in tumour cells and stromal cells. MMP-1 expression in stromal cells showed a significant association with luminal A and luminal B, HER2 overexpressing and triple-negative breast cancer subtypes.

Conclusions

The most important finding of this study was the independent prognostic value of MMP-1 as well as Ki-67 and bcl-2 expression in tumour cells. Our study showed also that both tumoural and stromal MMP-1 expression is associated with breast tumour progression and poor prognosis. A significant difference of MMP-1 expression by cancer associated stromal cells in luminal A, luminal B and triple-negative breast cancer classes was also demonstrated.

Please see related commentary article http://www.biomedcentral.com/1741-7015/9/95

What does matrix metalloproteinase-1 expression in patients with breast cancer really tell us?

Molecular and biochemical expressions of matrix metalloproteinases in breast cancer tissue and cells offers promise in helping us understand the breast cancer microenvironment, and also in the future it is hoped this will improve its detection, treatment and prognosis. In a retrospective study recently published in BMC Cancer, microenvironment predisposing to breast cancer progression, metastatic behavior and the expression of matrix metalloproteinase-1 (MMP-1) and its correlation with well-known biochemical, molecular and clinicopathologic factors in breast cancer cells and cancer-associated stromal cells was examined; this study also analyzed patient survival in different breast cancer subtypes. The positive correlation in breast tumor and stromal cells between MMP-1 expression and several markers of tumor grade and stage provide us with some useful new insights into important questions about the molecular profiling of the stromal microenvironment in metastatic breast cancer. The study showed that MMP-1 expression is strongly associated with poor clinical outcome, so now we look forward to future larger studies in breast cancer patients in which we can relate wider MMP molecular profiling to identify lethal tumor and stromal microenvironments predisposing to breast cancer progression, metastatic behavior and poor prognosis. Please see related article http://www.biomedcentral.com/1471-2407/11/348.

Homing of cancer cells to the bone

A variety of tumor cells preferentially home to the bone. The homing of cancer cells to the bone represents a multi-step process that involves malignant progression of the tumor, invasion of the tumor through the extracellular matrix and the blood vessels and settling of the tumor cells in the bone. Gaining a greater understanding as to the mechanisms used by cancer cells in these processes will facilitate the design of drugs which could specifically target the homing process. In this review we will discuss the properties of tumor cells and the bone microenvironment which promote homing of a cancer cell to the bone. We will highlight the different steps and the molecular pathways involved when a cancer cell metastasize to the bone. Since bone is the major home for hematopoietic stem cells (HSCs), we will also highlight the similarities between the homing of cancer and HSC to the bone. Finally we will conclude with therapeutic and early detection strategies which can prevent homing of a cancer cell to the bone.

Matrix metalloproteinase 1: role in sarcoma biology

In carcinomas stromal cells participate in cancer progression by producing proteases such as MMPs. The expression MMP1 is a prognostic factor in human chondrosarcoma, however the role in tumor progression is unknown. Laser capture microdissection and In Situ hybridization were used to determine cellular origin of MMP1 in human sarcomas. A xenogenic model of tumor progression was then used and mice were divided in two groups: each harboring either the control or a stably MMP1 silenced cell line. Animals were sacrificed; the neovascularization, primary tumor volumes, and metastatic burden were assessed. LCM and RNA-ISH analysis revealed MMP1 expression was predominantly localized to the tumor cells in all samples of sarcoma (p = 0.05). The percentage lung metastatic volume at 5 weeks (p = 0.08) and number of spontaneous deaths secondary to systemic tumor burden were lower in MMP1 silenced cell bearing mice. Interestingly, this group also demonstrated a larger primary tumor size (p<0.04) and increased angiogenesis (p<0.01). These findings were found to be consistent when experiment was repeated using a second independent MMP1 silencing sequence. Prior clinical trials employing MMP1 inhibitors failed because of a poor understanding of the role of MMPs in tumor progression. The current findings indicating tumor cell production of MMP1 by sarcoma cells is novel and highlights the fundamental differences in MMP biology between carcinomas and sarcomas. The results also emphasize the complex roles of MMP in tumor progression of sarcomas. Not only does metastasis seem to be affected by MMP1 silencing, but also local tumor growth and angiogenesis are affected inversely.

Thioredoxin-like 2 regulates human cancer cell growth and metastasis via redox homeostasis and NF-κB signaling

Cancer cells have an efficient antioxidant system to counteract their increased generation of ROS. However, whether this ability to survive high levels of ROS has an important role in the growth and metastasis of tumors is not well understood. Here, we demonstrate that the redox protein thioredoxin-like 2 (TXNL2) regulates the growth and metastasis of human breast cancer cells through a redox signaling mechanism. TXNL2 was found to be overexpressed in human cancers, including breast cancers. Knockdown of TXNL2 in human breast cancer cell lines increased ROS levels and reduced NF-κB activity, resulting in inhibition of in vitro proliferation, survival, and invasion. In addition, TXNL2 knockdown inhibited tumorigenesis and metastasis of these cells upon transplantation into immunodeficient mice. Furthermore, analysis of primary breast cancer samples demonstrated that enhanced TXNL2 expression correlated with metastasis to the lung and brain and with decreased overall patient survival. Our studies provided insight into redox-based mechanisms underlying tumor growth and metastasis and suggest that TXNL2 could be a target for treatment of breast cancer.

Overexpression of matrix metalloproteinase (MMP)-1 and -9 in central giant cell lesions of the jaws: implications for clinical behavior

OBJECTIVE

The aim of this study was to investigate the relationship between the immunohistochemical expression of MMP-1 and MMP-9 with the clinical behavior of central giant cell lesions (CGCLs) of the jaws.

STUDY DESIGN

Paraffin-embedded tissue from 30 aggressive and 12 nonaggressive CGCLs was assessed for the expression of MMP-1 and MMP-9 using immunohistochemistry.

RESULTS

Although cellular immunolocalization patterns of MMP-1 and MMP-9 were similar, mean values of expression estimation/SID scores of each protease were significantly higher in aggressive CGCLs in comparison with nonaggressive lesions. Moreover, linear regression analysis showed that there was a reasonably good correlation not only between the expression estimation but also among SID scores of the 2 proteolytic enzymes.

CONCLUSION

The findings of this study suggest a role for MMP-1 and MMP-9 in the resorptive activity of different cellular groups in CGCLs and indicate that differences in immunoreactivity of these 2 proteolytic enzymes may underlie the distinct clinical behavior.

Identification of a metalloprotease-chemokine signaling system in the ovarian cancer microenvironment: implications for antiangiogenic therapy

Ovarian cancer is a lethal gynecologic malignancy that may benefit from new therapies that block key paracrine pathways involved in tumor-stromal interactions and tumor vascularity. It was recently shown that matrix metalloprotease-1 (MMP1) activation of the G protein-coupled receptor protease-activated receptor-1 (PAR1) is an important stimulator of angiogenesis and metastasis in peritoneal mouse models of ovarian cancer. In the present study, we tested the hypothesis that MMP1-PAR1 promotes angiogenesis through its paracrine control of angiogenic chemokine receptors. We found that MMP1-PAR1 activation induces the secretion of several angiogenic factors from ovarian carcinoma cells, most prominently interleukin (IL)-8, growth-regulated oncogene-alpha (GRO-alpha), and monocyte chemoattractant protein-1. The secreted IL-8 and GRO-alpha acts on endothelial CXCR1/2 receptors in a paracrine manner to cause robust endothelial cell proliferation, tube formation, and migration. A cell-penetrating pepducin, X1/2pal-i3, which targets the conserved third intracellular loop of both CXCR1 and CXCR2 receptors, significantly inhibited endothelial cell proliferation, tube formation, angiogenesis, and ovarian tumor growth in mice. Matrigel plugs mixed with MMP1-stimulated, OVCAR-4-conditioned media showed a dramatic 33-fold increase in blood vessel formation in mice. The X1/2pal-i3 pepducin completely inhibited MMP1-dependent angiogenesis compared with a negative control pepducin or vehicle. Conversely, a vascular endothelial growth factor-directed antibody, Avastin, suppressed angiogenesis in mice but, as expected, was unable to inhibit IL-8 and GRO-alpha-dependent endothelial tube formation in vitro. These studies identify a critical MMP1-PAR1-CXCR1/2 paracrine pathway that might be therapeutically targeted for ovarian cancer treatment.

Matrix metalloproteinase-1 expression can be upregulated through mitogen-activated protein kinase pathway under the influence of human epidermal growth factor receptor 2 synergized with estrogen receptor

In our previous work, Ets-1 upregulates human epidermal growth factor receptor 2 (HER2) induced matrix metalloproteinase 1 (MMP-1) expression. Based on the above knowledge and result, we hypothesized that estrogen receptor (ER) and its signaling pathway may affect MMP-1 expression under the influence of HER2. In addition, we investigated how the HER2 pathway cross-talk with the ER signaling pathway in genomic and nongenomic action of ER using reverse transcription-PCR, Western blot analysis, and ELISA assay. The results showed that ER-alpha expression increased MMP-1 expression under the presence of HER2. These upregulatory effects were mediated mainly by mitogen-activated protein kinase pathway and were reversed by downregulation of HER2 and/or ER. Activator protein DNA binding activity was involved in the MMP-1 expression. In summary, our results showed that ER can upregulate MMP-1 expression under the influence of HER2 in MCF-7 cells. In addition, this upregulatory effect was found to be mediated by mitogen-activated protein kinase pathway. MMP-1 might be an assigned target in interaction between ER and HER2.

Matrix metalloproteinase and G protein coupled receptors: co-conspirators in the pathogenesis of autoimmune disease and cancer

Similarities in the pathologies of autoimmune diseases and cancer have been noted for at least 30 years. Inflammatory cytokines and growth factors mediate cell proliferation, and proteinases, especially the collagenase, Matrix Metalloproteinase-1 (MMP-1), contribute to disease progression by remodeling the extracellular matrix and modulating the microenvironment. This review focuses on two cancers (melanoma and breast) and on the autoimmune disorder, rheumatoid arthritis (RA), and discusses the activated stromal cells found in these diseases. MMP-1 was originally thought to function only to degrade interstitial collagens, but recent studies have revealed novel roles for MMP-1 involving the G protein-coupled receptors: the chemokine receptor, CXCR-4, and Protease Activated Receptor-1 (PAR-1). Cooperativity between MMP-1 and CXCR4/SDF-1 signaling influences the behavior of activated fibroblasts in both RA and cancer. Further, MMP-1 is a vital part of an autocrine/paracrine MMP-1/PAR-1 signal transduction axis, a function that amplifies its potential to remodel the matrix and to modify cell behavior. Finally, new therapeutic agents directed at MMP-1 and G protein-coupled receptors are emerging. Even though these agents are more specific in their targets than past therapies, these targets are often shared between RA and cancer, underscoring fundamental similarities between autoimmune disorders and some cancers.

CXCR4 and matrix metalloproteinase-1 are elevated in breast carcinoma-associated fibroblasts and in normal mammary fibroblasts exposed to factors secreted by breast cancer cells

The complex molecular communications that occur between neoplastic and stromal cells within the tumor microenvironment play an integral role in breast cancer pathogenesis. Carcinoma-associated fibroblasts (CAF) produce tumor-enhancing factors and have been strongly implicated in breast cancer development. Similar to the way in which tumors have been compared with "wounds that never heal," CAFs have been equated to activated fibroblasts, which are present in inflammatory environments, in which they aid in wound healing through tissue remodeling and repair. Matrix metalloproteinase-1 (MMP-1) and G protein-coupled receptor, CXCR4, are elevated in these activated fibroblasts, in which they facilitate angiogenesis and matrix degradation, processes that are also vital to breast cancer metastasis. In this study, we investigated MMP-1 and CXCR4 expression in normal human mammary fibroblasts (HMF) exposed to soluble breast cancer factors. Historically, elevated CXCR4 expression is associated with breast cancer cells. However, we show that soluble factors secreted by SUM102 breast cancer cells stimulated the expression of MMP-1 and CXCR4 in HMFs. As a result, these stromal cells acquired an invasive and migratory phenotype. To confirm the clinical relevancy of our findings, we analyzed CAFs obtained from primary breast cancers. These cells also displayed elevated MMP-1 and CXCR4 levels compared with counterpart fibroblasts, and were more invasive and migratory. Together, our data suggest that soluble breast cancer factors initiate the transdifferentiation of normal HMFs to tumor-promoting CAFs, and that through the induction of MMP-1 and CXCR4 levels, these cells exhibit an invasive and migratory phenotype.

Matrix metalloproteinase-1 and thrombin differentially activate gene expression in endothelial cells via PAR-1 and promote angiogenesis

Many tumor types express matrix metalloproteinase-1 (MMP-1); its collagenase activity facilitates both tumor cell invasion and metastasis. MMP-1 expression is also associated with increased angiogenesis; however, the exact mechanism by which this occurs is not clear. MMP-1 proteolytically activates protease activated receptor-1 (PAR-1), a thrombin receptor that is highly expressed in endothelial cells. Thrombin is also present in the tumor microenvironment, and its activation of PAR-1 is pro-angiogenic. It is currently unknown whether MMP-1 activation of PAR-1 induces angiogenesis in a similar or different manner compared with thrombin. We sought to determine the mechanism by which MMP-1 promotes angiogenesis and to compare the effects of MMP-1 with those of thrombin. Our results demonstrate that via PAR-1, MMP-1 activates mitogen-activated protein kinase signaling cascades in microvessel endothelial cells. Although thrombin activation of PAR-1 also induces signaling through these pathways, the time-course of activation appears to vary. Gene expression analysis revealed a possible consequence of these signaling differences as MMP-1 and thrombin induce expression of different subsets of pro-angiogenic genes. Furthermore, the combination of thrombin and MMP-1 is more angiogenic than either protease alone. These data demonstrate that MMP-1 acts directly on endothelial cells as a pro-angiogenic signaling molecule and also suggest that the effects of MMP-1 may complement the activity of thrombin to better facilitate angiogenesis and promote tumor progression.