Earlier Onset of Tumoral Angiogenesis in Matrix Metalloproteinase-19–Deficient Mice

Potential novel markers in IBD and CRC diagnostics. Are MMP-19 and RAGE promising candidates?

AIMS

Inflammatory bowel diseases and colorectal cancer are serious intestinal disorders with continuously increasing incidence. Many aspects of etiopathogenesis still remain unclear. There is an urgent need to improve early diagnostics and markers indicating the progression of the disease. The aim of our study was to analyze the expression of matrix metalloproteinase-19 (MMP-19), and the receptor for advanced glycation end-products (RAGE) in different cell subpopulations in inflammatory bowel diseases (IBD) and colorectal cancer (CRC) compared to the tissue in the vicinity of pathological processes.

METHODS

Expression of both markers in epithelium, macrophages and vessels were evaluated in IBD and CRC groups. They were detected using immunohistochemistry in paraffin sections.

RESULTS

There were significant differences between the expression of MMP-19 on macrophages and vessels among healthy and cancer tissues. In both, macrophages and vessels were significantly lower levels in cancer tissues. The expression of MMP-19 on vessels was also significantly different between peritumoral and cancer tissues (higher levels in peritumoral tissue). RAGE expression in macrophages was significantly different between healthy and cancer tissues and between peritumoral and cancer tissues. There was significantly lower expression in cancer tissues than in healthy and peritumoral tissues. Expression of RAGE in vessels was significantly different just in the comparison of healthy and peritumoral tissues (higher levels in healthy tissues).

CONCLUSION

Both markers seem to be promising potential auxiliary markers in IBD and CRC diagnostics. They can also improve evaluation of disease progression.

Identification of macrophage correlated biomarkers to predict the prognosis in patients with intrahepatic cholangiocarcinoma

Background

It has been shown that tumor-associated immune cells, particularly macrophages, play a fundamental role in the development and treatment response of intrahepatic cholangiocarcinoma (ICC). However, little is known about macrophages at the single cellular level of ICC patients.

Methods

ScRNA-seq from Zhang et al. was used in the present study to identify the genes differentially expressed in ICCs. Furthermore, transcriptomic data from TCGA datasets, IHC and flowcytometry from our cohort were used to confirm the findings. Kaplan-Meier and TIDE scores were also used for prognostic analysis and ICB responses.

Results

A significant number of macrophages were found in ICCs as compared to adjacent tissues. We then extracted, processed, and classified the macrophages from the ICCs and adjacent tissues into 12 clusters. Significantly, the macrophages from the ICC exhibited an immunosuppressed state in terms of both signature gene expression and functional enrichment. Furthermore, our results indicate that, of the 10 selective tumor-promoting genes of macrophages, only MMP19 and SIRPα can predict ICB responses in ICCs. Although a higher expression of MMP19 and SIRPα predict a poor prognosis for ICCs without immunotherapy after surgery, patients with high SIRPα expression were more sensitive to immunotherapy, whereas those with high MMP19 expression were not sensitive to immunotherapy. To define the mechanisms, we found that SIRPα^hi ICCs exhibited an increased enrichment KEGG pathway of leukocyte transendothelial migration and neutrophil extracellular trap formation. The increased immune cell infiltration will increase sensitivity to immunotherapy.

Conclusion

Collectively, macrophages are critical to the immune status of ICCs, and MMP19 and SIRPα can predict prognosis and ICB responses for ICCs.

miRNA-486-5p: signaling targets and role in non-malignant disease

MicroRNAs (miRNAs) are short non-coding RNAs, highly conserved between species, that are powerful regulators of gene expression. Aberrant expression of miRNAs alters biological processes and pathways linked to human disease. miR-486-5p is a muscle-enriched miRNA localized to the cytoplasm and nucleus, and is highly abundant in human plasma and enriched in small extracellular vesicles. Studies of malignant and non-malignant diseases, including kidney diseases, have found correlations with circulating miR-486-5p levels, supporting its role as a potential biomarker. Pre-clinical studies of non-malignant diseases have identified miR-486-5p targets that regulate major signaling pathways involved in cellular proliferation, migration, angiogenesis, and apoptosis. Validated miR-486-5p targets include phosphatase and tensin homolog (PTEN) and FoXO1, whose suppression activates phosphatidyl inositol-3-kinase (PI3K)/Akt signaling. Targeting of Smad1/2/4 and IGF-1 by miR-486-5p inhibits transforming growth factor (TGF)-β and insulin-like growth factor-1 (IGF-1) signaling, respectively. Other miR-486-5p targets include matrix metalloproteinase-19 (MMP-19), Sp5, histone acetyltransferase 1 (HAT1), and nuclear factor of activated T cells-5 (NFAT5). In this review, we examine the biogenesis, regulation, validated gene targets and biological effects of miR-486-5p in non-malignant diseases.

Gene Expression and Resistance to Glucocorticoid-Induced Apoptosis in Acute Lymphoblastic Leukemia: A Brief Review and Update

BACKGROUND

Resistance to glucocorticoid (GC)-induced apoptosis in Acute Lymphoblastic Leukemia (ALL), is considered one of the major prognostic factors for the disease. Prednisolone is a corticosteroid and one of the most important agents in the treatment of acute lymphoblastic leukemia. The mechanics of GC resistance are largely unknown and intense ongoing research focuses on this topic.

AIM

The aim of the present study is to review some aspects of GC resistance in ALL, and in particular of Prednisolone, with emphasis on previous and present knowledge on gene expression and signaling pathways playing a role in the phenomenon.

METHODS

An electronic literature search was conducted by the authors from 1994 to June 2019. Original articles and systematic reviews selected, and the titles and abstracts of papers screened to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

RESULTS

Identification of gene targets responsible for glucocorticoid resistance may allow discovery of drugs, which in combination with glucocorticoids may increase the effectiveness of anti-leukemia therapies. The inherent plasticity of clinically evolving cancer justifies approaches to characterize and prevent undesirable activation of early oncogenic pathways.

CONCLUSION

Study of the pattern of intracellular signal pathway activation by anticancer drugs can lead to development of efficient treatment strategies by reducing detrimental secondary effects.

ATP5A1 Participates in Transcriptional and Posttranscriptional Regulation of Cancer-Associated Genes by Modulating Their Expression and Alternative Splicing Profiles in HeLa Cells

Background: Aberrant expression and alternative splicing of oncogenes are the driving events in tumor initiation and development. But how these events are regulated in cancer cells is largely unknown. Functions of ATP5A1, an important mitochondrial ATP synthase gene, in transcriptional and posttranscriptional regulation were explored in this study. Methods: ATP5A1 was overexpressed using plasmid-transformed HeLa cells, and its influence on cell apoptosis and proliferation is evaluated. Transcriptome sequencing was then performed using RNA-seq to study the changes in gene expression and regulation of alternative splicing events. Validation of the implicated genes was achieved using RT-qPCR analysis. Results: It was found that ATP5A1 could significantly promote cellular apoptosis, but it had no influence on cell proliferation. ATP5A1 overexpression significantly increased the expression levels of genes associated with the innate immune response, angiogenesis, and collagen catabolic processes. This included enrichment of MMP2 and MMP19. It was also found that ATP5A1 could interfere with the alternative splicing of hundreds of genes associated with glucose homeostasis, HIF-1 signaling activation, and several pathways associated with cancers. Eight ATP5A1-regulated differentially expressed genes and 3 genes altered by splicing were selected and validated using RT-qPCR analysis. Conclusions: In summary, we illustrate the regulatory functions of ATP5A1 on the transcriptome of HeLa cells by exploring its influence on gene expression and alternative splicing. The results suggest that ATP5A1 may play an important regulatory role in cervical cancer cells by regulating expression and alternative splicing of cancer-associated genes. This study provides novel insights into the current understanding of the mechanisms of ATP5A1 on carcinogenesis and cancer progression.

Matrix metalloproteinases participation in the metastatic process and their diagnostic and therapeutic applications in cancer

Matrix metalloproteinases (MMPs) participate from the initial phases of cancer onset to the settlement of a metastatic niche in a second organ. Their role in cancer progression is related to their involvement in the extracellular matrix (ECM) degradation and in the regulation and processing of adhesion and cytoskeletal proteins, growth factors, chemokines and cytokines. MMPs participation in cancer progression makes them an attractive target for cancer therapy. MMPs have also been used for theranostic purposes in the detection of primary tumor and metastatic tissue in which a particular MMP is overexpressed, to follow up on therapy responses, and in the activation of cancer cytotoxic pro-drugs as part of nano-delivery-systems that increase drug concentration in a specific tumor target. Herein, we review MMPs molecular characteristics, their synthesis regulation and enzymatic activity, their participation in the metastatic process, and how their functions have been used to improve cancer treatment.

MMP-19 deficiency causes aggravation of colitis due to defects in innate immune cell function

Matrix metalloproteinases (MMPs) are potential biomarkers for disease activity in inflammatory bowel disease (IBD). However, clinical trials targeting MMPs have not succeeded, likely due to poor understanding of the biological functions of individual MMPs. Here, we explore the role of MMP-19 in IBD pathology. Using a DSS-induced model of colitis, we show evidence for increased susceptibility of Mmp-19-deficient (Mmp-19(-/-)) mice to colitis. Absence of MMP-19 leads to significant disease progression, with reduced survival rates, severe tissue destruction, and elevated levels of pro-inflammatory modulators in the colon and plasma, and failure to resolve inflammation. There was a striking delay in neutrophil infiltration into the colon of Mmp-19(-/-) mice during the acute colitis, leading to persistent inflammation and poor recovery; this was rescued by reconstitution of irradiated Mmp-19(-/-) mice with wild-type bone marrow. Additionally, Mmp-19-deficient macrophages exhibited decreased migration in vivo and in vitro and the mucosal barrier appeared compromised. Finally, chemokine fractalkine (CX3CL1) was identified as a novel substrate of MMP-19, suggesting a link between insufficient processing of CX3CL1 and cell recruitment in the Mmp-19(-/-) mice. MMP-19 proves to be a critical factor in balanced host response to colonic pathogens, and for orchestrating appropriate innate immune response in colitis.

The Long Noncoding RNA MALAT-1 Is Highly Expressed in Ovarian Cancer and Induces Cell Growth and Migration

BACKGROUND

Metastasis associated in lung adenocarcinoma transcript-1 (MALAT-1) is overexpressed during cancer progression and promotes cell migration and invasion in many solid tumors. However, its role in ovarian cancer remains poorly understood.

METHODS

Expressions of MALAT-1 were detected in 37 normal ovarian tissues and 45 ovarian cancer tissues by reverse transcription polymerase chain reaction (RT-PCR). Cell proliferation was observed by CCK-8 assay; Flow cytometry was used to measure cell cycle and apoptosis; Cell migration was detected by transwell migration and invasion assay. In order to evaluate the function of MALAT-1, shRNA combined with DNA microarray and Functional enrichment analysis were performed to determine the transcriptional effects of MALAT-1 silencing in OVCAR3 cells. RNA and protein expression were measured by qRT-PCR and Western blotting, respectively.

RESULTS

We found that upregulation of MALAT-1 mRNA in ovarian cancer tissues and enhanced MALAT-1 expression was associated with FIGO stage. Knockdown of MALAT-1 expression in OVCAR3 cells inhibited cell proliferation, migration, and invasion, leading to G0/G1 cell cycle arrest and apoptosis. Overexpressed MALAT-1 expression in SKOV3 cells promoted cell proliferation, migration and invasion. Downregulation of MALAT-1 resulted in significant change of gene expression (at least 2-fold) in 449 genes, which regulate proliferation, cell cycle, and adhesion. As a consequence of MALAT-1 knockdown, MMP13 protein expression decreased, while the expression of MMP19 and ADAMTS1 was increased.

CONCLUSIONS

The present study found that MALAT-1 is highly expressed in ovarian tumors. MALAT-1 promotes the growth and migration of ovarian cancer cells, suggesting that MALAT-1 may be an important contributor to ovarian cancer development.

The progress of angiogenic factors in the development of leukemias

Angiogenic factors have been demonstrated to play important roles in modulating angiogenesis of solid tumors. Recently, accumulating studies extensively indicated that some angiogenic factors widely exist in malignant cells of hematologic malignancy, which regulated the expression of a number of genes that were involved in abnormal proliferation, differentiation and apoptosis of these cells. With deep research of angiogenic factors, its expression, function and regulatory mechanism were gradually elucidated, and some of them were related to the development and prognosis of leukemia, or provide more possible strategies for treatment of patients with leukemia. Herein, we summarize the progress in study of some important angiogenic factors and hematological malignancies.

Matrix metalloproteinases and genetic mouse models in cancer research: a mini-review

Carcinogenesis is a multistep and also a multifactorial process that involves agents like genetic and environmental factors. Matrix metalloproteinases (MMPs) are major proteolytic enzymes which are involved in cancer cell migration, invasion, and metastasis. Genetic variations in genes encoding the MMPs were shown in human studies to influence cancer risk and phenotypic features of a tumor. The complex role of MMPs seems to be important in the mechanism of carcinogenesis, but it is not well recognized. Rodent studies concentrated particularly on the better understanding of the biological functions of the MMPs and their impact on the pathological process, also through the modification of Mmp genes. This review presents current knowledge and the existing evidence on the importance of selected MMPs in genetic mouse models of cancer and human genetic association studies. Further, this work can be useful for scientists studying the role of the genetic impact of MMPs in carcinogenesis.

Potent 19-norvitamin D analogs for prostate and liver cancer therapy

The active form of vitamin D(3), 1α,25(OH)(2)D(3) or calcitriol, is known to inhibit the proliferation and invasiveness of many types of cancer cells, including prostate and liver cancer cells. These findings support the use of 1α,25(OH)(2)D(3) for prostate and liver cancer therapy. However, 1α,25(OH)(2)D(3) can cause hypercalcemia, thus, analogs of 1α,25(OH)(2)D(3) that are less calcemic but exhibit potent antiproliferative activity would be attractive as therapeutic agents. We have developed 2α-functional group substituted 19-norvitamin D(3) analogs with and without 14-epimerization. Among them, 2α- and 2β-(3-hydroxypropyl)-1α,25-dihydroxy-19-norvitamin D(3) (MART-10 and -11, respectively) and 14-epi-2α- and 14-epi-2β-(3-hydroxypropyl)-1α,25-dihydroxy-19-norvitamin D(3) (14-epi-MART-10 and 14-epi-MART-11, respectively) were found to be the most promising. In this review, we discuss the synthesis of this unique class of vitamin D analogs, the molecular mechanism of anticancer actions of vitamin D, and the biological evaluation of these analogs for potential application to the prevention and treatment of prostate and liver cancer.

Matrix metalloproteinase Mmp-1a is dispensable for normal growth and fertility in mice and promotes lung cancer progression by modulating inflammatory responses

Human MMP-1 is a matrix metalloproteinase repeatedly associated with many pathological conditions, including cancer. Thus, MMP1 overexpression is a poor prognosis marker in a variety of advanced cancers, including colorectal, breast, and lung carcinomas. Moreover, MMP-1 plays a key role in the metastatic behavior of melanoma, breast, and prostate cancer cells. However, functional and mechanistic studies on the relevance of MMP-1 in cancer have been hampered by the absence of an in vivo model. In this work, we have generated mice deficient in Mmp1a, the murine ortholog of human MMP1. Mmp1a(-/-) mice are viable and fertile and do not exhibit obvious abnormalities, which has facilitated studies of cancer susceptibility. These studies have shown a decreased susceptibility to develop lung carcinomas induced by chemical carcinogens in Mmp1a(-/-) mice. Histopathological analysis indicated that tumors generated in Mmp1a(-/-) mice are smaller than those of wild-type mice, consistently with the idea that the absence of Mmp-1a hampers tumor progression. Proteomic analysis revealed decreased levels of chitinase-3-like 3 and accumulation of the receptor for advanced glycation end-products and its ligand S100A8 in lung samples from Mmp1a(-/-) mice compared with those from wild-type. These findings suggest that Mmp-1a could play a role in tumor progression by modulating the polarization of a Th1/Th2 inflammatory response to chemical carcinogens. On the basis of these results, we propose that Mmp1a knock-out mice provide an excellent in vivo model for the functional analysis of human MMP-1 in both physiological and pathological conditions.

Missing the target: matrix metalloproteinase antitargets in inflammation and cancer

Matrix metalloproteinases (MMPs) are reputed to cause the inflammatory tissue destruction characterizing chronic inflammatory diseases and to degrade basement membrane collagen, thereby facilitating cancer cell metastasis. However, following the disappointing MMP drug cancer trials, recent studies using mouse models of disease coupled with high-throughput methods for substrate discovery have revealed surprising and unexpected new biological roles of MMPs in inflammatory diseases and cancer in vivo. Thus, MMPs modify signaling pathways and regulate the activity of whole families of cytokines of the immune response by precise proteolytic processing. By cleaving and inactivating cytokine-binding proteins and protease inhibitors, cytokine activities are unmasked and activities of diverse proteases are increased in an interconnected protease web. With new substrates come new roles, and 10 of 24 murine MMPs have antitumorigenic and anti-inflammatory roles making them drug antitargets; that is, their beneficial actions should not be inhibited. Here, we examine whether the discovery that MMPs are drug antitargets for one disease might pave the way for their use for other indications or whether this is a serious threat to the development of MMP inhibitors.

Hepatoprotective effect of MMP-19 deficiency in a mouse model of chronic liver fibrosis

Liver fibrosis is characterized by the deposition and increased turnover of extracellular matrix. This process is controlled by matrix metalloproteinases (MMPs), whose expression and activity dynamically change during injury progression. MMP-19, one of the most widely expressed MMPs, is highly expressed in liver; however, its contribution to liver pathology is unknown. The aim of this study was to elucidate the role of MMP-19 during the development and resolution of fibrosis by comparing the response of MMP-19-deficient (MMP19KO) and wild-type mice upon chronic liver CCl(4)-intoxication. We show that loss of MMP-19 was beneficial during liver injury, as plasma ALT and AST levels, deposition of fibrillar collagen, and phosphorylation of SMAD3, a TGF-ß1 signaling molecule, were all significantly lower in MMP19KO mice. The ameliorated course of the disease in MMP19KO mice likely results from a slower rate of basement membrane destruction and ECM remodeling as the knockout mice maintained significantly higher levels of type IV collagen and lower expression and activation of MMP-2 after 4 weeks of CCl(4)-intoxication. Hastened liver regeneration in MMP19KO mice was associated with slightly higher IGF-1 mRNA expression, slightly increased phosphorylation of Akt kinase, decreased TGF-ß1 mRNA levels and significantly reduced SMAD3 phosphorylation. In addition, primary hepatocytes isolated from MMP19KO mice showed impaired responsiveness towards TGF-ß1 stimulation, resulting in lower expression of Snail1 and vimentin mRNA. Thus, MMP-19-deficiency improves the development of hepatic fibrosis through the diminished replacement of physiological extracellular matrix with fibrotic deposits in the beginning of the injury, leading to subsequent changes in TGF-ß and IGF-1 signaling pathways.

Co-expression of MMP-14 and MMP-19 predicts poor survival in human glioma

AIM

Matrix metalloproteinase (MMP)-14 and MMP-19 have been demonstrated to play an important role in the development of human gliomas. However, their prognostic values are not clear. The aim of this study was to investigate whether co-expression of MMP-14 and MMP-19 has prognostic relevance in human gliomas.

METHODS

Immunohistochemistry and western blot were used to investigate the expression of MMP-14 and MMP-19 proteins in 128 patients with gliomas.

RESULTS

The expression levels of MMP-14 and MMP-19 proteins in glioma tissues were both significantly higher (both P < 0.001) than those in non-neoplastic brain tissues according to the immunohistochemistry analysis, which was confirmed by the western blot analysis. Additionally, the overexpression of either MMP-14 or MMP-19 was significantly associated with the advanced WHO grade (both P = 0.02), the low Karnofsky performance score (KPS) (P = 0.008 and 0.01, respectively) and the poor overall survival (both P = 0.01). Moreover, the Multivariate Cox proportional-hazards regression analysis revealed that the increased expressions of MMP-14 and MMP-19 were both independent prognostic factors for poor overall survival (both P = 0.02). Furthermore, the co-expression of MMP-14 and MMP-19 was additively and more significantly (P = 0.006) associated with adverse prognosis in patients with gliomas than respective expression of MMP-14 and MMP-19.

CONCLUSIONS

These findings indicated for the first time that the co-expression of MMP-14 and MMP-19 is significantly correlated with prognosis in glioma patients, suggesting that the co-expression of these proteins may be used as both an early diagnostic and independent prognostic marker.

Human matrix metalloproteinases: an ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes.

Microarray and proteomic analysis of breast cancer cell and osteoblast co-cultures: role of osteoblast matrix metalloproteinase (MMP)-13 in bone metastasis

Dynamic reciprocal interactions between a tumor and its microenvironment impact both the establishment and progression of metastases. These interactions are mediated, in part, through proteolytic sculpting of the microenvironment, particularly by the matrix metalloproteinases, with both tumors and stroma contributing to the proteolytic milieu. Because bone is one of the predominant sites of breast cancer metastases, we used a co-culture system in which a subpopulation of the highly invasive human breast cancer cell line MDA-MB-231, with increased propensity to metastasize to bone, was overlaid onto a monolayer of differentiated osteoblast MC3T3-E1 cells in a mineralized osteoid matrix. CLIP-CHIP® microarrays identified changes in the complete protease and inhibitor expression profile of the breast cancer and osteoblast cells that were induced upon co-culture. A large increase in osteoblast-derived MMP-13 mRNA and protein was observed. Affymetrix analysis and validation showed induction of MMP-13 was initiated by soluble factors produced by the breast tumor cells, including oncostatin M and the acute response apolipoprotein SAA3. Significant changes in the osteoblast secretomes upon addition of MMP-13 were identified by degradomics from which six novel MMP-13 substrates with the potential to functionally impact breast cancer metastasis to bone were identified and validated. These included inactivation of the chemokines CCL2 and CCL7, activation of platelet-derived growth factor-C, and cleavage of SAA3, osteoprotegerin, CutA, and antithrombin III. Hence, the influence of breast cancer metastases on the bone microenvironment that is executed via the induction of osteoblast MMP-13 with the potential to enhance metastases growth by generating a microenvironmental amplifying feedback loop is revealed.

Matrix metalloproteinases: protective roles in cancer

The original notion that matrix metalloproteinases (MMPs) act as tumour and metastasis-promoting enzymes by clearing a path for tumour cells to invade and metastasize has been challenged in the last decade. It has become clear that MMPs are involved in numerous steps of tumour progression and metastasis, and hence are now considered to be multifaceted proteases. Moreover, more recent experimental evidence indicates that some members of the MMP family behave as tumour-suppressor enzymes and should therefore be regarded as anti-targets in cancer therapy. The complexity of the pro- and anti-tumorigenic and -metastatic functions might partly explain why broad-spectrum MMP inhibitors failed in phase III clinical trials. This review will provide a focussed overview of the published data on the tumour-suppressive behaviour of MMPs.

Hypercholesterolaemia, signs of islet microangiopathy and altered angiogenesis precede onset of type 2 diabetes in the Goto-Kakizaki (GK) rat

AIMS/HYPOTHESIS

The adult non-obese Goto-Kakizaki (GK) rat model of type 2 diabetes, particularly females, carries in addition to hyperglycaemia a genetic predisposition towards dyslipidaemia, including hypercholesterolaemia. As cholesterol-induced atherosclerosis may be programmed in utero, we looked for signs of perinatal lipid alterations and islet microangiopathy. We hypothesise that such alterations contribute towards defective pancreas/islet vascularisation that might, in turn, lead to decreased beta cell mass. Accordingly, we also evaluated islet inflammation and endothelial activation in both prediabetic and diabetic animals.

METHODS

Blood, liver and pancreas were collected from embryonic day (E)21 fetuses, 7-day-old prediabetic neonates and 2.5-month-old diabetic GK rats and Wistar controls for analysis/quantification of: (1) systemic variables, particularly lipids; (2) cholesterol-linked hepatic enzyme mRNA expression and/or activity; (3) pancreas (fetuses) or collagenase-isolated islet (neonates/adults) gene expression using Oligo GEArray microarrays targeted at rat endothelium, cardiovascular disease biomarkers and angiogenesis, and/or RT-PCR; and (4) pancreas endothelial immunochemistry: nestin (fetuses) or von Willebrand factor (neonates).

RESULTS

Systemic and hepatic cholesterol anomalies already exist in GK fetuses and neonates. Hyperglycaemic GK fetuses exhibit a similar percentage decrease in total pancreas and islet vascularisation and beta cell mass. Normoglycaemic GK neonates show systemic inflammation, signs of islet pre-microangiopathy, disturbed angiogenesis, collapsed vascularisation and altered pancreas development. Concomitantly, GK neonates exhibit elevated defence mechanisms.

CONCLUSIONS/INTERPRETATION

These data suggest an autoinflammatory disease, triggered by in utero programming of cholesterol-induced islet microangiopathy interacting with chronic hyperglycaemia in GK rats. During the perinatal period, GK rats show also a marked deficient islet vascularisation in conjunction with decreased beta cell mass.

Matrix metalloproteinase-19 inhibits growth of endothelial cells by generating angiostatin-like fragments from plasminogen

Background

Angiogenesis is the process of forming new blood vessels from existing ones and requires degradation of the vascular basement membrane and remodeling of extracellular matrix (ECM) in order to allow endothelial cells to migrate and invade into the surrounding tissue. Matrix metalloproteinases (MMPs) are considered to play a central role in the remodeling of basement membranes and ECM. However, MMPs contribute to vascular remodeling not only by degrading ECM components. Specific MMPs enhance angiogenesis via several ways; they help pericytes to detach from vessels undergoing angiogenesis, release ECM-bound angiogenic growth factors, expose cryptic pro-angiogenic integrin binding sites in the ECM, generate promigratory ECM component fragments, and cleave endothelial cell-cell adhesions. MMPs can also negatively influence the angiogenic process through generating endogenous angiogenesis inhibitors by proteolytic cleavage. Angiostatin, a proteolytic fragment of plasminogen, is one of the most potent antagonists of angiogenesis that inhibits migration and proliferation of endothelial cells. Reports have shown that metalloelastase, pancreas elastase, plasmin reductase, and plasmin convert plasminogen to angiostatin.

Results

We report here that MMP-19 processes human plasminogen in a characteristic cleavage pattern to generate three angiostatin-like fragments with a molecular weight of 35, 38, and 42 kDa. These fragments released by MMP-19 significantly inhibited the proliferation of HMEC cells by 27% (p = 0.01) and reduced formation of capillary-like structures by 45% (p = 0.05) compared with control cells. As it is known that angiostatin blocks hepatocyte growth factor (HGF)-induced pro-angiogenic signaling in endothelial cells due to structural similarities to HGF, we have analyzed if the plasminogen fragments generated by MMP-19 interfere with this pathway. As it involves the activation of c-met, the receptor of HGF, we could show that MMP-19-dependent processing of plasminogen decreases the phosphorylation of c-met.

Conclusion

Altogether, MMP-19 exhibits an anti-angiogenic effect on endothelial cells via generation of angiostatin-like fragments.

Gene profiling of the rat medial collateral ligament during early healing using microarray analysis

Ligament heals in a synchronized and complex series of events. The remodeling process may last months or years. Experimental evidence suggests the damaged ligament does not recover its normal functional properties. Specific mechanisms to prevent scar formation and to regenerate the original mechanical function remain elusive but likely involve regulation of creeping substitution. Creeping substitution creates a larger hypercellular, hypervascular, and disorganized granulation tissue mass that results in an inefficient and nonregenerative wound healing process for the ligament. Control of creeping substitution may limit the extent of this tissue compromise and reduce the time necessary for healing. The objective of this study is to better understand the mechanism behind scar formation by identifying the extracellular matrix factors and other unique genes of interest differentially expressed during rat ligament healing via microarray. For this study, rat medial collateral ligaments were either surgically transected or left intact. Ligaments were collected at day 3 or 7 postinjury and used for microarray, quantitative PCR, and/or immunohistochemistry. Results were compared with the normal intact ligament. We demonstrate that early ligament healing is characterized by the modulation of several inflammatory and extracellular matrix factors during the first week of injury. Specifically, a number of matrix metalloproteinases and collagens are differentially and significantly expressed during early ligament healing. Additionally, we demonstrate the modulation of three novel genes, periostin, collagen-triple helix repeat containing-1, and serine protease 35 in our ligament healing model. Together, control of granulation tissue creeping substitution and subsequent downstream scar formation is likely to involve these factors.

Catalytic activity of Matrix metalloproteinase-19 is essential for tumor suppressor and anti-angiogenic activities in nasopharyngeal carcinoma

The association of Matrix metalloproteinase-19 (MMP19) in the development of nasopharyngeal carcinoma (NPC) was identified from differential gene profiling, which showed MMP19 was one of the candidate genes down-regulated in the NPC cell lines. In this study, quantitative RT-PCR and Western blot analysis showed MMP19 was down-regulated in all seven NPC cell lines. By tissue microarray immunohistochemical staining, MMP19 appears down-regulated in 69.7% of primary NPC specimens. Allelic deletion and promoter hypermethylation contribute to MMP19 down-regulation. We also clearly demonstrate that the catalytic activity of MMP19 plays an important role in antitumor and antiangiogenesis activities in comparative studies of the wild-type and the catalytically inactive mutant MMP19. In the in vivo tumorigenicity assay, only the wild-type (WT), but not mutant, MMP19 transfectants suppress tumor formation in nude mice. In the in vitro colony formation assay, WT MMP19 dramatically reduces colony-forming ability of NPC cell lines, when compared to the inactive mutant. In the tube formation assay of human umbilical vein endothelial cells and human microvascular endothelial cells (HMEC-1), secreted WT MMP19, but not mutant MMP19, induces reduction of tube-forming ability in endothelial cells with decreased vascular endothelial growth factor (VEGF) in conditioned media detected by enzyme-linked immunosorbent assay (ELISA). The anti-angiogenic activity of WT MMP19 is correlated with suppression of tumor formation. These results now clearly show that catalytic activity of MMP19 is essential for its tumor suppressive and anti-angiogenic functions in NPC.

Matrix metalloproteinase-19 deficiency promotes tenascin-C accumulation and allergen-induced airway inflammation

Matrix metalloproteinases (MMPs) recently appeared as key regulators of inflammation, allowing the recruitment and clearance of inflammatory cells and modifying the biological activity of many peptide mediators by cleavage. MMP-19 is newly described, and it preferentially cleaves matrix proteins such as collagens and tenascin-C. The role of MMP-19 in asthma has not been described to date. The present study sought to assess the expression of MMP-19 in a murine asthma model, and to address the biological effects of MMP-19 deficiency in mice. Allergen-exposed, wild-type mice displayed increased expression of MMP-19 mRNA and an increased number of MMP-19-positive cells in the lungs, as detected by immunohistochemistry. After an allergen challenge of MMP-19 knockout (MMP-19(-/-)) mice, exacerbated eosinophilic inflammation was detected in bronchoalveolar lavage fluid and bronchial tissue, along with increased airway responsiveness to methacholine. A shift toward increased T helper-2 lymphocyte (Th2)-driven inflammation in MMP-19(-/-) mice was demonstrated by (1) increased numbers of cells expressing the IL-33 receptor T(1)/ST(2) in lung parenchyma, (2) increased IgG(1) levels in serum, and (3) higher levels of IL-13 and eotaxin-1 in lung extracts. Tenascin-C was found to accumulate in peribronchial areas of MMP-19(-/-) after allergen challenges, as assessed by Western blot and immunohistochemistry analyses. We conclude that MMP-19 is a new mediator in asthma, preventing tenascin-C accumulation and directly or indirectly controlling Th2-driven airway eosinophilia and airway hyperreactivity. Our data suggest that MMP-19 may act on Th2 inflammation homeostasis by preventing the accumulation of tenascin protein.

Pleiotropic roles of matrix metalloproteinases in tumor angiogenesis: contrasting, overlapping and compensatory functions

A number of extensive reviews are available discussing the roles of MMPs in various aspects of cancer progression from benign tumor formation to overt cancer present with deadly metastases. This review will focus specifically on the evidence functionally linking the MMPs and tumor-induced angiogenesis in various in vivo models. Emphasis has been placed on the cellular origin of the MMPs in tumor tissue, the requirement of proMMP activation and the resulting proteolytic activity for the induction and progression of tumor angiogenesis, and the pleiotropic roles for some of the MMPs. The functional mechanisms of the angiogenic MMPs are discussed as well as their catalytic detection in complex biological systems. In addition, the contribution of active MMPs to metastatic spread and establishment of secondary metastasis will be discussed in view of the findings indicating that MMPs are involved in the preparation of pre-metastatic niches. Finally, the most recent evidence, indicating the pro-metastatic consequences of anti-angiogenic therapies employing MMP inhibitors will be presented as examples highlighting possible outcomes of interfering with the pleiotropic nature of the MMP functionality.

Matrix metalloproteinase proteomics: substrates, targets, and therapy

Proteomics encompasses powerful techniques termed 'degradomics' for unbiased high-throughput protease substrate discovery screens that have been applied to an important family of extracellular proteases, the matrix metalloproteinases (MMPs). Together with the data generated from genetic deletion and transgenic mouse models and genomic profiling, these screens can uncover the diverse range of MMP functions, reveal which MMPs and MMP-mediated pathways exacerbate pathology, and which are involved in protection and the resolution of disease. This information can be used to identify and validate candidate drug targets and antitargets, and is critical for the development of new inhibitors of MMP function. Such inhibitors may target either the MMP directly in a specific manner or pathways upstream and downstream of MMP activity that are mediating deleterious effects in disease. Since MMPs do not operate alone but are part of the 'protease web', it is necessary to use system-wide approaches to understand MMP proteolysis in vivo, to discover new biological roles and their potential for therapeutic modification.

MMPs regulate both development and immunity in the tribolium model insect

BACKGROUND

Matrix metalloproteinases (MMPs) are evolutionarily conserved and multifunctional effector molecules in development and homeostasis. In spite of previous, intensive investigation in vitro and in cell culture, their pleiotrophic functions in vivo are still not well understood.

METHODOLOGY/PRINCIPAL FINDINGS

We show that the genetically amenable beetle Tribolium castaneum represents a feasible model organism to explore MMP functions in vivo. We silenced expression of three insect-type Tribolium MMP paralogs and their physiological inhibitors, TIMP and RECK, by dsRNA-mediated genetic interference (RNAi). Knock-down of MMP-1 arrested development during pupal morphogenesis giving phenotypes with altered antennae, compound eyes, wings, legs, and head. Parental RNAi-mediated knock-down of MMP-1 or MMP-2 resulted in larvae with non-lethal tracheal defects and with abnormal intestines, respectively, implicating additional roles of MMPs during beetle embryogenesis. This is different to findings from the fruit fly Drosophila melanogaster, in which MMPs have a negligible role in embryogenesis. Confirming pleiotrophic roles of MMPs our results also revealed that MMPs are required for proper insect innate immunity because systemic knock-down of Tribolium MMP-1 resulted in significantly higher susceptibility to the entomopathogenic fungus Beauveria bassiana. Moreover, mRNA levels of MMP-1, TIMP, and RECK, and also MMP enzymatic activity were significantly elevated in immune-competent hemocytes upon stimulation. To confirm collagenolytic activity of Tribolium MMP-1 we produced and purified recombinant enzyme and determined a similar collagen IV degrading activity as observed for the most related human MMP, MMP-19.

CONCLUSIONS/SIGNIFICANCE

This is the first study, to our knowledge, investigating the in vivo role of virtually all insect MMP paralogs along with their inhibitors TIMP and RECK in both insect development and immunity. Our results from the Tribolium model insect indicate that MMPs regulate tracheal and gut development during beetle embryogenesis, pupal morphogenesis, and innate immune defense reactions thereby revealing the evolutionarily conserved roles of MMPs.

Additional MDA-MB-231 breast cancer cell matrix metalloproteinases promote invasiveness

We are interested in two aspects of a given type of metastatic breast cancer: which potentially cancer-relevant genes are expressed and which factors determine invasiveness. Using reverse transcription real-time PCR, we detected gene expression of 26 matrix metalloproteinases (MMPs) in MDA-MB-231 breast cancer cells, including those of MMP-12, MMP-16 variant 2, MMP-19, MMP-20, MMP-21, MMP-23, MMP-24, MMP-25, MMP-25 variant 2, MMP-L1, MMP-26, MMP-27, and MMP-28, in contrast to the 13 MMPs detected until now in these cells. We found that MMP genes are expressed at widely different levels in these cells, over five orders of magnitude. After individual siRNA-induced depletions, we found that six additional species of cancer cell MMPs promote invasiveness in MDA-MB-231 cells: MMP-3, MMP-11, MMP-12, MMP-17, MMP-19, and MMP-23, thus raising the total to 12 endogenous MMPs which do so in these cells. The data support the conclusion that some cancer cell MMPs, although expressed at low levels, are needed for cancer trait in MDA-MB-231 cells, and that several endogenous MMPs play non-redundant roles in this process. The mRNA level of MMP-11, but not of other MMPs, rose substantially following individual siRNA-targeted depletion of cancer cell MMP-17 mRNA, while no MMP mRNA increased appreciably after degradation of other MMP mRNAs. This supports the conclusion that MMP-17 may be a member of an intracellular signaling pathway which downregulates MMP-11 mRNA.

Matrix metalloproteinase-8 functions as a metastasis suppressor through modulation of tumor cell adhesion and invasion

Collagenase-2 (matrix metalloproteinase-8, MMP-8) is an MMP mainly produced by neutrophils and associated with many inflammatory conditions. We have previously described that MMP-8 plays a protective role in cancer through its ability to regulate the inflammatory response induced by carcinogens. Moreover, it has been reported that experimental manipulation of the expression levels of this enzyme alters the metastatic behavior of human breast cancer cells. In this work, we have used mutant mice deficient in MMP-8 and syngenic melanoma and lung carcinoma tumor cells lines overexpressing this enzyme to further explore the putative antimetastatic potential of MMP-8. We report herein that MMP-8 prevents metastasis formation through the modulation of tumor cell adhesion and invasion. Thus, tumor cells overexpressing MMP-8 have an increased adhesion to extracellular matrix proteins, whereas their invasive ability through Matrigel is substantially reduced when compared with control cells. Analysis of MMP-8 in breast cancer patients revealed that the expression of this metalloproteinase by breast tumors correlates with a lower incidence of lymph node metastasis and confers good prognosis to these patients. On this basis, we propose that MMP-8 is a tumor protective factor, which also has the ability to reduce the metastatic potential of malignant cells in both mice and human.

MMP19 is essential for T cell development and T cell-mediated cutaneous immune responses

Matrix metalloproteinase-19 (MMP19) affects cell proliferation, adhesion, and migration in vitro but its physiological role in vivo is poorly understood. To determine the function of MMP19, we generated mice deficient for MMP19 by disrupting the catalytic domain of mmp19 gene. Although MMP19-deficient mice do not show overt developmental and morphological abnormalities they display a distinct physiological phenotype. In a model of contact hypersensitivity (CHS) MMP19-deficient mice showed impaired T cell-mediated immune reaction that was characterized by limited influx of inflammatory cells, low proliferation of keratinocytes, and reduced number of activated CD8(+) T cells in draining lymph nodes. In the inflamed tissue, the low number of CD8(+) T cells in MMP19-deficient mice correlated with low amounts of proinflammatory cytokines, especially lymphotactin and interferon-inducible T cell alpha chemoattractant (I-TAC). Further analyses showed that T cell populations in the blood of immature, unsensitized mice were diminished and that this alteration originated from an altered maturation of thymocytes. In the thymus, thymocytes exhibited low proliferation rates and the number of CD4(+)CD8(+) double-positive cells was remarkably augmented. Based on the phenotype of MMP19-deficient mice we propose that MMP19 is an important factor in cutaneous immune responses and influences the development of T cells.

Identification of a lepidopteran matrix metalloproteinase with dual roles in metamorphosis and innate immunity

Matrix metalloproteinases (MMPs) are key enzymes in mammalian tissue remodeling and inflammation. Recently, we postulated that an endogenous MMP expressed in the lepidopteran model Galleria mellonella during metamorphosis causes degradation of collagen-IV, which in turn results in activation of innate immunity. Here, we report that degradation of collagen-IV by hemocytes is enhanced upon injection of bacterial lipopolysaccharide (LPS), and that this activity is sensitive to the MMP-inhibitor GM6001. Therefore, we screened for enzymes behind this activity and identified the first MMP from Lepidoptera (Gm1-MMP), and the third from insects. Gm1-MMP shares homology with the first MMP from Drosophila (Dm1-MMP) known to be essential for tissue remodeling during metamorphosis. Using quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) analysis, we confirmed up-regulation of Gm1-MMP expression after pupation, when extracellular matrix breakdown of larval tissues occurs. In addition, we determined that LPS challenge induces Gm1-MMP expression in hemocytes, implicating its participation in collagen-IV degradation upon septic injury. These results suggest dual roles of Gm1-MMP in innate immunity and metamorphosis. Interestingly, our phylogenetic analysis elucidates that Gm1-MMP share highest similarity with human MMP-19 and MMP-28, whose functions in mammalian wounding and inflammatory response have recently been demonstrated; hence, the present findings may provide insights into the evolutionarily conserved features of MMPs.

Quantification of in vivo tumor invasion and vascularization by computerized image analysis

The matrix-inserted surface transplantation model is an in vivo assay used to analyse the kinetics of tumor-vessel interactions during different stages of skin carcinoma progression. This system allows the study of host-tumor interface, i.e. penetration of tumor cells into normal host tissue as well as infiltration of normal host cells into the tumor. In the present study, image analysis algorithms for processing and quantifying the extent of such migratory and tissue remodeling events are presented. The proposed method is non-parametric and its originality lies in its particularity to take into account the specific geometry of tumor-host interface. This methodology is validated by evaluating the contribution of matrix metalloproteases (MMPs) in skin carcinoma invasion and vascularization through pharmacological and genetic approaches.

Breast cancer progression: insights into multifaceted matrix metalloproteinases

The restricted view of matrix metalloproteinases (MMPs) as simple destroyers of extracellular matrix components has largely ignored their substantial contribution in many aspects of cancer development and metastatic dissemination. Over the last few years, the relevance of MMPs in the processing of a large array of extracellular and cell surface-associated proteins has grown considerably. Our knowledge about the complex functions of MMPs and how their contribution may differ throughout cancer progression is rapidly expanding. These new findings provide several explanations for the lack of success of MMP inhibition in clinical trials. A complete understanding of MMP biology is needed before considering them, their substrates or their products as therapeutic targets. In this review, we explore the different faces of MMP implication in breast cancer progression by considering both clinical and fundamental aspects.

Emerging roles of proteases in tumour suppression

Proteases have long been associated with cancer progression because of their ability to degrade extracellular matrices, which facilitates invasion and metastasis. However, recent studies have shown that these enzymes target a diversity of substrates and favour all steps of tumour evolution. Unexpectedly, the post-trial studies have also revealed proteases with tumour-suppressive effects. These effects are associated with more than 30 different enzymes that belong to three distinct protease classes. What are the clinical implications of these findings?

Emerging roles of ADAM and ADAMTS metalloproteinases in cancer

A disintegrin and metalloproteinases (ADAMs) are a recently discovered family of proteins that share the metalloproteinase domain with matrix metalloproteinases (MMPs). Among this family, structural features distinguish the membrane-anchored ADAMs and the secreted ADAMs with thrombospondin motifs referred to as ADAMTSs. By acting on a large panel of membrane-associated and extracellular substrates, they control several cell functions such as adhesion, fusion, migration and proliferation. The current review addresses the contribution of these proteinases in the positive and negative regulation of cancer progression as mainly mediated by the regulation of growth factor activities and integrin functions.

Matrix metalloproteinase inhibitors as therapy for inflammatory and vascular diseases

Matrix metalloproteinases (MMPs) have outgrown the field of extracellular-matrix biology and have progressed towards being important regulatory molecules in cancer and inflammation. This rise in status was accompanied by the development of various classes of inhibitors. Although clinical trials with synthetic inhibitors for the treatment of cancer were disappointing, recent data indicate that the use of selective inhibitors might lead to new therapies for acute and chronic inflammatory and vascular diseases. In this Review, we compare the major classes of MMP inhibitors and advocate that future drug discovery should be based on crucial insights into the differential roles of specific MMPs in pathophysiology obtained with animal models, including knockout studies.

Extracellular proteolysis in transgenic mouse models of breast cancer

Growth and invasion of breast cancer require extracellular proteolysis in order to physically restructure the tissue microenvironment of the mammary gland. This pathological tissue remodeling process depends on a collaboration of epithelial and stromal cells. In fact, the majority of extracellular proteases are provided by stromal cells rather than cancer cells. This distinct expression pattern is seen in human breast cancers and also in transgenic mouse models of breast cancer. The similar expression patterns suggest that transgenic mouse models are ideally suited to study the role of extracellular proteases in cancer progression. Here we give a status report on protease intervention studies in transgenic models. These studies demonstrate that proteases are involved in all stages of breast cancer progression from carcinogenesis to metastasis. Transgenic models are now beginning to provide vital mechanistic insight that will allow us to combat breast cancer invasion and metastasis with new protease-targeted drugs.