The 2G Single Nucleotide Polymorphism (SNP) in the MMP-1 Promoter Contributes to High Levels of MMP-1 Transcription in MCF-7/ADR Breast Cancer Cells

Abstract

Degradation of stromal collagens in the extracellular matrix is mediated largely by matrix metalloproteinase-1 (MMP-1; collagenase-1), and high constitutive levels of MMP-1 in breast cancer correlate with a poor prognosis and invasive disease. MMP-1 expression is, in part, controlled by the mitogen-activated protein kinase (MAPK) pathway(s), which may target several activator protein-1 (AP-1) and polyoma enhancing activity-3/E26 virus (PEA3/ETS) sites within the promoter. An additional ETS site in the MMP-1 promoter is conferred by a single nucleotide polymorphism (SNP) at -1607 bp, when two guanines (5'-GGAT-3'; '2G allele/SNP') are present instead of one guanine (5'-GAT-3'; '1G allele/SNP'). This SNP is adjacent to an AP-1 site at -1602 bp, and in the presence of the 2G allele (ETS site), these sites cooperate to induce higher levels of transcription. ERK 1/2 is one component of the MAPK pathway and is constitutively active in MCF-7/ADR breast cancer cells, which are 1G/2G heterozygotes. This study demonstrates that when these cells are treated with PD098059, an ERK-specific inhibitor, MMP-1 mRNA levels are significantly decreased, suggesting that high constitutive expression of MMP-1 in these cells results from continuous ERK 1/2 activation. Using transient transfection, we determined that this signaling pathway targets different AP-1/ETS sites, depending upon which allele is present. Furthermore, in these cells, the AP-1 site at -1602 bp enhances transcription in the presence of the 2G SNP, but represses transcription from the 1G SNP. Finally, inhibiting ERK signaling and MMP-1 expression blocks type I collagen degradation and reduces the invasive ability of the MCF-7/ADR cells. We conclude that ERK 1/2 signaling and the 2G SNP mediate high levels of MMP-1 expression, which may contribute to the invasive potential of these breast cancer cells.

The collagenase-1 (MMP-1) gene promoter polymorphism - 1607/2G is associated with favourable prognosis in patients with colorectal cancer

“…A limitation of our study was that we did not confirm whether this polymorphism was indeed functional. There is, however, ample supportive evidence establishing the functionality of this polymorphism in both normal stromal cells (Wyatt et al, 2002) and tumour cells, including melanoma (Tower et al, 2003a) and breast cancer cells (Tower et al, 2003b). These studies confirmed that cells containing a 2G allele displayed enhanced transcriptional activity compared to cells harbouring the 1G allele.…”

Matrix Metalloproteinase-1 Promoter Polymorphism and Lung Cancer Risk

“…The mechanism for this histologic difference is still under investigation, but there are two distinct theories. The MMP-1 À1607 1G/2G polymorphism is adjacent to an activating protein-1 site at À1,602 bp, which may cooperate with the 2G allele (Ets site) to induce higher levels of transcription (5), and the activator protein-1 site is inhibitory in the context of the 1G allele, but activating the 2G allele (6). If this activator protein-1 site is mutated, it could lead to a substantial increase in expression of the 1G allele where the difference in transcription between 1G and 2G alleles is abolished and the MMP-1 expression is similar between the two alleles (6).…”

“…MMP-1 (collagenase) may degrade the interstitial types I, II, and III collagens (1) and contribute to tumor initiation and development by altering the cellular microenvironment that facilitates tumor formation (2)(3)(4). There is a single nucleotide polymorphism at À1,607 bp in the MMP-1 promoter, with the 2G allele associated with higher expression levels (5,6). Cells expressing the 2G allele may provide a mechanism for more aggressive matrix degradation, thereby facilitating cancer progression.…”

Lessons in Signaling and Tumorigenesis from Polyomavirus Middle T Antigen

“…A single nucleotide polymorphism in tumor tissue results in the creation of an additional bipartite site, which leads to increased stromelysin expression and is associated with a more invasive tumor phenotype (295). How would synergy between Ap-1 and Ets work?…”