Degradation of basement membranes and stromal extracellular matrix (ECM) is crucial for invasion and metastasis of malignant cells. Degradation of ECM is initiated by proteinases secreted by different cell types participating in tumor cell invasion, and increased expression or activity of every known class of proteinases (metallo-, serine-, aspartic-, and cysteine) has been linked to malignancy and invasion of tumor cells. Studies performed over the last decade have revealed that matrix metalloproteinases (MMPs) play a crucial role in tumor invasion. Expression of MMP genes is transcriptionally regulated by a variety of extracellular factors including cytokines, growth factors, and cell contact to ECM. This review will summarize the current view on the role of MMPs in tumor growth, invasion, and survival, and focus on the role of mitogen-activated protein kinases and AP-1 and ETS transcription factors in the regulation of MMP gene expression during invasion process.

https://faseb.onlinelibrary.wiley.com/doi/pdf/10.1096/fasebj.13.8.781

Regulation of matrix metalloproteinase expression in tumor invasion

Matrix metalloproteinases (MMPs) are a major group of enzymes that regulate cell-matrix composition. MMP genes show a highly conserved modular structure. Ample evidence exists on the role of MMPs in normal and pathological processes, including embryogenesis, wound healing, inflammation, arthritis, cardiovascular diseases, pulmonary diseases and cancer. The expression patterns of MMPs have interesting implications for the use of MMP inhibitors as therapeutic agents. Insights might be gained as to the preference for a general MMP inhibitor as opposed to an inhibitor designed to be specific for certain MMP family members as it relates to a defined disease state, and may give clues to potential side effects. The signalling pathways that lead to induction of expression of MMPs are still incompletely understood, but certain patterns are beginning to emerge. Regarding inhibition of MMP expression at the level of kinase pathways, it is possible that selective chemical inhibitors for distinct signalling pathways (e.g. MAPK, PKC) will hopefully, soon be available for initial clinical trials. Overexpression of selective dual specificity MAPK phosphatases have been shown to prevent MMP promoter activation which could also be used as a novel strategy to prevent activation of AP-1 and ETS transcription factors and MMP promoters in vivo. Interactions between members of different transcription factors provide fine-tuning of the transcriptional regulation of MMP promoter activity. MMPs play a crucial role in tumor invasion. Although the expression of MMPs in malignancies has been studied widely, the specific role of distinct MMPs in the progression of cancer may be more complex than has been assumed. For example, it has recently been shown that MMP-3, MMP-7, MMP-9 and MMP-12 can generate angiostatin from plasminogen, indicating that their expression in peritumoral area may in fact serve to limit angiogenesis and thereby inhibit tumor growth and invasion. The recent view about the role of stromal cells in the progression of cancer cell growth and metastasis is particularly interesting, and additional studies about the regulation of MMP gene expression and activity in malignancies are needed to understand the role and regulation of MMPs in tumor cell invasion.

Regulation of matrix metalloproteinases: an overview.

Matrix metalloproteinases (MMPs) are a family of enzymes that proteolytically degrade various components of the extracellular matrix (ECM). Angiogenesis is the process of forming new blood vessels from existing ones and requires degradation of the vascular basement membrane and remodeling of the ECM in order to allow endothelial cells to migrate and invade into the surrounding tissue. MMPs participate in this remodeling of basement membranes and ECM. However, it has become clear that MMPs contribute more to angiogenesis than just degrading ECM components. Specific MMPs have been shown to enhance angiogenesis by helping to detach pericytes from vessels undergoing angiogenesis, by releasing ECM-bound angiogenic growth factors, by exposing cryptic proangiogenic integrin binding sites in the ECM, by generating promigratory ECM component fragments, and by cleaving endothelial cell-cell adhesions. MMPs can also contribute negatively to angiogenesis through the generation of endogenous angiogenesis inhibitors by proteolytic cleavage of certain collagen chains and plasminogen and by modulating cell receptor signaling by cleaving off their ligand-binding domains. A number of inhibitors of MMPs that show antiangiogenic activity are already in early stages of clinical trials, primarily to treat cancer and cancer-associated angiogenesis. However, because of the multiple effects of MMPs on angiogenesis, careful testing of these MMP inhibitors is necessary to show that these compounds do not actually enhance angiogenesis.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1582-4934.2005.tb00355.x

Matrix metalloproteinases and angiogenesis

Mitogen-activated protein kinase (MAPK) cascades are involved in inflammation and tissue destruction in rheumatoid arthritis (RA). In particular, c-Jun N-terminal kinase (JNK) is highly activated in RA fibroblast-like synoviocytes and synovium. However, defining the precise function of this kinase has been difficult because a selective JNK inhibitor has not been available. We now report the use of a novel selective JNK inhibitor and JNK knockout mice to determine the function of JNK in synoviocyte biology and inflammatory arthritis. The novel JNK inhibitor SP600125 (anthra[1,9-cd]pyrazol-6(2H)-one) completely blocked IL-1--induced accumulation of phospho-Jun and induction of c-Jun transcription in synoviocytes. Furthermore, AP-1 binding and collagenase mRNA accumulation were completely suppressed by SP600125. In contrast, complete inhibition of p38 had no effect, and ERK inhibition had only a modest effect. The essential role of JNK was confirmed in cultured synoviocytes from JNK1 knockout mice and JNK2 knockout mice, each of which had a partial defect in IL-1--induced AP-1 activation and collagenase-3 expression. Administration of SP600125 modestly decreased the rat paw swelling in rat adjuvant-induced arthritis. More striking was the near-complete inhibition of radiographic damage that was associated with decreased AP-1 activity and collagenase-3 gene expression. Therefore, JNK is a critical MAPK pathway for IL-1--induced collagenase gene expression in synoviocytes and in joint arthritis, indicating that JNK is an important therapeutic target for RA.

/pdf/c-jun-n-terminal-kinase-is-required-for-metalloproteinase-5giilsgu8a.pdf

c-Jun N-terminal kinase is required for metalloproteinase expression and joint destruction in inflammatory arthritis

Part of the cellular response to toxins, physical stresses and inflammatory cytokines occurs by signalling via the stress-activated protein kinase (SAPK) and p38 reactivating kinase pathways. This results in modification of cellular gene expression. These stress-responsive kinase pathways are structurally similar, but functionally distinct, from the archetypal mitogen-activated protein kinases (MAPKs or ERKs). The ERK pathway is a hierarchical cascade originating at the cell membrane with receptors for mitogens or growth factors, which recruit, via adapter proteins and exchange factors, the small guanosine triphosphatase (GTPase) Ras (see fig. 1). Ras activates raf, a serine threonine kinase, which activates MEK (MAPK/ERK kinase). MEK, in turn, phosphorylates and activates ERK1 and ERK2, which translocate to the nucleus and transactivate transcription factors, changing gene expression to promote growth, differentiation or mitosis. By transducing signals through a cascade of kinases, several options for control are introduced for amplifying and/or modifying the output signal. The SAPK and p38 pathways are also hierarchically arranged, but less is known about the upstream components and the downstream effects of stimulation of these pathways. Among the processes modulated by stress-responsive pathways are apoptosis, transformation, development, immune activation, inflammation and adaptation to environmental changes. This review outlines the upstream componentry of these pathways that interact with a variety of agonists to modify the activity of SAPK and p38, and explores the downstream functions of this activation.

The stress-activated protein kinase pathways

Activation of p38α MAPK Enhances Collagenase-1 (Matrix Metalloproteinase (MMP)-1) and Stromelysin-1 (MMP-3) Expression by mRNA Stabilization

Enhancement of Fibroblast Collagenase (Matrix Metalloproteinase-1)Gene Expression by Ceramide Is Mediated by Extracellular Signal-regulated and Stress-activated Protein Kinase Pathways

Expression of collagenase-3 [matrix metalloproteinase-13 (MMP-13)] has been previously demonstrated in squamous-cell carcinomas of both the head and neck and the vulva, cutaneous basal-cell carcinomas, chondrosarcomas and melanomas. Using in situ hybridization, MMP-13 mRNA expression was detected in 13 of 23 (52%) urinary bladder transitional-cell carcinomas (TCCs). Expression was restricted to cells in the invading edges of tumors. No expression of MMP-13 mRNA could be detected in normal urothelium. As detected by immunohistochemistry, MMP-13 protein showed an expression pattern similar to that of MMP-13 mRNA. Expression of MMP-13 mRNA and protein was also detected in 2 bladder carcinoma cell lines (RT4 and T24). In these cell lines, TNF-alpha potently induced MMP-13 mRNA expression. Retinoids and a selective p38 inhibitor, SB203580, potently inhibited MMP-13 mRNA expression. Our results demonstrate MMP-13 expression in human urinary bladder carcinoma cells in vivo and in vitro and suggest that MMP-13 may serve as a marker for transformation and invasion in urinary bladder TCCs.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1097-0215%2820001101%2988%3A3%3C417%3A%3AAID-IJC14%3E3.0.CO%3B2-G

Niina Reunanen

Papers

Activation of p38α MAPK Enhances Collagenase-1 (Matrix Metalloproteinase (MMP)-1) and Stromelysin-1 (MMP-3) Expression by mRNA Stabilization

Enhancement of Fibroblast Collagenase (Matrix Metalloproteinase-1)Gene Expression by Ceramide Is Mediated by Extracellular Signal-regulated and Stress-activated Protein Kinase Pathways

Expression of collagenase-3 (matrix metalloproteinase-13) in transitional-cell carcinoma of the urinary bladder

Activation of extracellular signal-regulated kinase 1/2 inhibits type I collagen expression by human skin fibroblasts.

Matrix Metalloproteinases in Cancer Cell Invasion