Overexpression of Collagenase 1 (MMP-1) Is Mediated by the ERK Pathway in Invasive Melanoma Cells

Abstract

Melanoma progresses as a multistep process where the thickness of the lesion and depth of tumor invasion are the best prognostic indicators of clinical outcome. Degradation of the interstitial collagens in the extracellular matrix is an integral component of tumor invasion and metastasis, and much of this degradation is mediated by collagenase-1 (MMP-1), a member of the matrix metalloproteinase (MMP) family. MMP-1 levels increase during melanoma progression where they are associated with shorter disease-free survival. The Ras/Raf/ MEK/ERK mitogen-activated protein kinase (MAPK) pathway is a major regulator of melanoma cell proliferation. Recently, BRAF has been identified as a common site of activating mutations, and, although many reports focus on its growth-promoting effects, this pathway has also been implicated in progression toward metastatic disease. In this study, we describe four melanoma cell lines that produce high levels of MMP-1 constitutively. In each cell line the Ras/Raf/MEK/ERK pathway is constitutively active and is the dominant pathway driving the production of MMP-1. Activation of this pathway arises due to either an activating mutation in BRAF (three cell lines) or autocrine fibroblast growth factor signaling (one cell line). Furthermore, blocking MEK/ ERK activity inhibits melanoma cell proliferation and abrogates collagen degradation, thus decreasing their metastatic potential. Importantly, this inhibition of invasive behavior can occur in the absence of any detectable changes in cell proliferation and survival. Thus, constitutive activation of this MAPK pathway not only promotes the increased proliferation of melanoma cells but is also important for the acquisition of an invasive phenotype.

Helicobacter pylori Stimulates Gastric Epithelial Cell MMP-1 Secretion via CagA-dependent and -independent ERK Activation

“…That MEK inhibition also regulates ERK activity and MMP-1 expression in rheumatoid synovial fibroblasts (36) and osteoarthritis chondrocytes (81) indicates that ERK pathway regulation of MMP-1 secretion is a conserved signaling pathway in cells involved with inflammation and erosion. MEK inhibition also reduces ERK activation, MMP-1 secretion, and collagenolysis, in invasive melanoma cells embedded in Type I collagen matrices (53). The mechanisms by which ERK regulates gastric cell MMP-1 secretion have not been determined, but ERK signaling in other cells reg-ulates MMP-1 secretion via AP-1 and ETS transcriptional activation (82).…”

Regulation of matrix metalloproteinase gene expression by a retinoid X receptor–specific ligand

“…The collagen degradation assay was performed as previously described (24,25). Briefly, fibrillar collagen preparations were made from Vitrogen 100 bovine type I collagen (Cohesion Technologies, Palo Alto, CA) according to the manufacturer's instructions.…”

“…We then quantified the collagen breakdown by recovering the medium from each well and weighing it (24,25). Recovered media volumes greater than the 1 ml (i.e., 1 gm) that was originally added demonstrated collagen breakdown, with liberation of media previously embedded in the matrix.…”

“…In humans, the MMP family currently encompasses 23 unique members, which degrade all constituents of the extracellular matrix (ECM) (5). The MMPs can be subdivided into 6 main classes (1,4,5), consisting of the collagenases (MMPs 1, 8, and 13), the gelatinases (MMPs 2 and 9), the stromelysins (MMPs 3, 10, and 11), the matrilysins (MMPs 7 and 26), the membrane-type MMPs (MMPs 14,15,16,17,24,and 25), and a diverse subgroup.The collagenase subgroup is unique in its ability to cleave fibrillar collagens, and their enzymatic activity represents a rate-limiting step in the degradation of collagen-containing tissues. MMP-1 is expressed by a range of cell types, including chondrocytes and fibroblasts, and is most effective against type III collagen.…”

“…In humans, the MMP family currently encompasses 23 unique members, which degrade all constituents of the extracellular matrix (ECM) (5). The MMPs can be subdivided into 6 main classes (1,4,5), consisting of the collagenases (MMPs 1, 8, and 13), the gelatinases (MMPs 2 and 9), the stromelysins (MMPs 3, 10, and 11), the matrilysins (MMPs 7 and 26), the membrane-type MMPs (MMPs 14,15,16,17,24,and 25), and a diverse subgroup.…”