Matrix metalloproteinase-1
(MMP1, MMP-1)

Collagenase (CLG, CLGN)
Fibroblast collagenase
Interstitial collagenase
EC Number: EC3.4.24.7

Gene: maps to 11q22-q23 (Pendas A.M. et al., 1996). It covers approximately 17 kb (Brinckerhoff C.E. et al., 1987).
mRNA: size: 2.1 kb.
Protein: like MMP8 (neutrophil collagenase) and MMP13 (collagenase 3), MMP1 may cleave the major components of the interstitial stroma, collagens type I and III.

MMPs have at least three domains: a prodomain, lost on enzyme activation, which contains a conserved cysteine residue; a catalytic domain of 106 to 119 residues which contains conserved structural metal-binding sites; and a highly conserved zinc-binding active site domain of 52 to 58 residues. Among the human MMPs, all but MMP17 have a signal peptide sequence and all but MMP7 have a C-terminal domain with homology to the protein hemopexin. Two subclasses of MMPs have additional domains that set them apart from the rest of the family. The two gelatinases, MMP2 and MMP9, each have a gelatin-binding domain inserted between the catalytic domain and the active site domain, and there are four membrane-associated MMPs, MMP14, 15, 16, and 17, which have transmembrane domains added on to the C-terminal domain. The membrane-associated enzymes, along with MMP11 are further distinguished by a short sequence inserted between the prodomain and the catalytic domain that has been postulated to be a furin-sensitive cleavage site important in the activation of these enzymes.

Two key structural motifs are conserved among all the MMPs. The first is the zinc-binding active site domain, a highly conserved stretch of 50 to 55 amino acids which contains three histidines occupying three of the coordination sites of the active site zinc ion. The second motif is the conserved sequence in the prodomain of the protein that contains a cysteine residue which is responsible for maintaining latency in proMMPs by occupying the fourth zinc coordination site with its sulphydryl group. Activation of proMMPs must, at some point in the mechanism, destabilize and break the zinc-sulfur bond.

Most MMPs appear to be secreted from cells in their inactive proforms, making of activation a key step in regulating the amount of degradative activity outside the cell. For most MMPs, including MMP1, 3, 7, and 9, serine proteases such as plasmin and urokinase-type plasminogen activator have been shown to initiate activation. Some MMPs may activate other members of the family. Thus, while MMP14, 15, and 16 can activate MMP2, MMP2 and 3 have been shown to be able to activate MMP9. The five MMPs with furin cleavage sites are postulated to be activated by furin.

The tissue inhibitors of metalloproteinases, or TIMPs are major inhibitors of MMPs.

Numerous studies have shown an association between the expression of MMPs and the invasive behavior and metastatic potential of tumors. Therefore, MMPs are important pharmacological targets, and a number of synthetic inhibitors have been developed.

Cell lines:
- Observations suggest that MCF-7 breastt cancer cells (BCC) in culture produce both soluble and membrane-bound factor(s) which stimulate the production of pro-MMPs (including MMP1) and TIMP-1 in neighbouring stromal cells, but the factor(s) released into the medium and that associated with cell membranes are probably different. Such communication between the normal and malignant cell types may, in part, assist the cancer cells to invade and metastasise (Ito A. et al., 1995).

- Activation of protein kinase C (PKC) bbut not of protein kinase A (PKA) was found to induce transcription of MMP1 and TIMP-1, possibly by the synthesis of transcription factor(s), in MCF-7 BCC (Ree A.H. et al., 1996).

- A higher level of MMP1 mRNA has been ffound in MDA-MB-231 BCC compared with the MCF-7 and T-47D BCC lines. In MDA-MB-231, MMP1 mRNA was inducible by EGF and TGF-alpha (Nutt J.E. and Lunec J., 1996).

- The expression of c-ets-1 was comparedd with invasiveness in vitro and expression of vimentin, E-cadherin, uPA, MMP-1 and MMP-3 in a panel of human breast cancer cell lines. An association was found between c-ets-1 expression and the invasive, epithelial to mesenchymal transition (EMT)-derived phenotype, which is typified by the expression of vimentin and the lack of E-cadherin. However, no clear quantitative or qualitative relationship between the expression of c-ets-1 and the three proteinases known to be regulated by c-ets-1, except that when they were expressed, it was only in the invasive c-ets-1-positive lines. uPA mRNAs were found in three of the four vimentin-positive lines, MMP-1 in two of the four, and MMP-3 could not be detected in any of the cell lines. Intriguingly, MDA-MB-435 cells, which exhibit the highest metastatic potential of these cell lines in nude mice, expressed vimentin and c-ets-1, but lacked expression of these three proteinases, at least under the culture conditions employed (Gilles C. et al., 1997).

- EGF was found to stimulate the motile and invasive activities specifically in the ErbB-2-overexpressing SK-BR-3 cells. Expression of extracellular matrix-degrading proteases including type I collagenase/MMP-1, 92 kDa type IV collagenase/MMP-9, uPA and uPA receptor were induced. EGF also transiently stimulated expression of the transcription factors Ets-1 and Ets-2. Reporter transfection assays revealed the activation of uPA and MMP-9 collagenase promoters by EGF and the requirement of each of the composite Ets and AP-1 transcription factor binding sites for an EGF response (Watabe T. et al., 1998).

- MMP1 produced by the MDA-MB-231 BCC waas found to enhance stromal matrix degradation by enabling the tumor cells to modulate their own invasive behavior (Benbow U. et al., 1999a).

- MMP1 repression by all-trans-retinoic acid (RA) in MDA-MB-231 BCC does not depend on the proximal AP-1 site at -73 bp, but, rather, requires sequences located in distal regions of the promoter. Transcriptional analyses and electrophoretic mobility shift assays suggest that a PEA3 site located at -3108 bp facilitates, at least in part, the effect of RA on MMP1 (Benbow U. et al., 1999b).

- Two invasive breast cancer cell lines (MDA-MB-231 and BT-549) were found to be more adherent and have greater migratory capacity on bone marrow fibroblasts than three non-invasive cell lines (MCF-7, T47D and BT-483). Inhibitors of matrix metalloproteases were able to attenuate the migration of MDA-MB-231 cells through bone marrow fibroblast monolayers, suggesting a role for these enzymes in the migration of breast cancer cells through bone marrow adherent layers. Co-culture of MDA-MB-231 cells and bone marrow fibroblasts resulted in augmentation of the levels of the matrix metalloproteases MMP-1 and MMP-2 in culture supernatants. Soluble factors produced by bone marrow fibroblasts were responsible for the increase in MMP-1 levels. However, maximal MMP-2 production was dependent on direct contract between the breast cancer cells and the bone marrow fibroblasts (Saad S. et al., 2000).

- Analysis of MMP expression by RT-PCR sshowed expression of MMP-1, MMP-3, and MMP-13 in highly invasive MDA-MB-231 BCC, but not in slightly invasive MCF-7, T-47D, and BT-20 cell lines. The extracellular secretion of MMP-1 and MMP-3 by MDA-MB 231 cells could be also shown by ELISA. TIMP-1 and TIMP-2 mRNAs were found in all cell lines, however, the extracellular secretion of both TIMPs was much higher in MDA-MB-231 cells than in the other cell lines. When the cells were cultured on Matrigel matrix, MMP-9 expression was induced in MDA-MB-231 cells only, as assessed by RT-PCR and zymography experiments. The invasive potential of MDA-MB-231 cells evaluated in vitro through Matrigel was significantly inhibited by the MMP inhibitor BB-2516 (Balduyck M et al., 2000).

- The expressions of 4224 genes were anaalysed for association with intrinsic or acquired doxorubicin (DOX) resistance. A cluster of overexpressed genes related to DOX resistance was observed. Included in this cluster was ABCB1 and MMP1, indicative of the invasive nature of resistant cells, and the oxytocin receptor (OXTR), a potential new therapeutic target. Overexpression of genes associated with xenobiotic transformation, cell transformation, cell signalling and lymphocyte activation was also associated with DOX resistance as was estrogen receptor negativity. In all carcinoma cells, compared with HBL100 a putatively normal breast epithelial cell line, a cluster of overexpressed genes was identified which included several keratins, in particular keratins 8 (KRT8) and 18 (KRT18) which are regulated through the ras signalling pathway. Analysis of genomic amplifications and deletions revealed specific genetic alterations common to both intrinsic and acquired DOX resistance including ABCB1, PGY3 (ABCB4) and BAK (Turton N.J. et al., 2001).

- CD147 (Basigin, EMMPRIN) is enriched oon the surface of tumor cells and is known to stimulate the production of MMPs by adjacent stromal cells. It has been found that CD147 engages in a homophilic interaction, predominantly through the first immunoglobulin domain. Anti-CD147 antibody 8G6 and recombinant CD147-Fc fusion protein markedly inhibited not only homophilic interaction, but also the production of secreted MMP-2 by MDA-MB-435 BCC and the MMP-2-dependent invasion of MDA-MB-435 cells through reconstituted basement-membrane Matrigel. Purified native CD147 induced the production of secreted MMP not only by dermal fibroblasts (MMP-1) but also by MDA-MB-435 cells themselves (MMP-2), suggesting homophilic CD147-binding may occur in the context of both heterotypic and homotypic cell-cell interactions. Purified deglycosylated CD147 failed to induce MMP-1 or MMP-2, but instead antagonized the MMP-1-inducing activity of purified native CD147 (Sun J. and Hemler M.E., 2001).

Tumors:
- Expression of mRNAs encoding MMP1, MMPP2 and MMP3, and of TIMP1 were studied in human mammary pathology by in situ hybridization and Northern blot analysis. Out of 6 benign lesions, 2 expressed MMP2 mRNAs. mRNAs encoding MMP1 and MMP3 were detectable in occasional stromal and tumor cells in 2 out of 17 carcinomas. Thirteen out of 17 cancers expressed MMP2 mRNA throughout the tumor in stromal cells close to noninvasive tumor clusters and well-differentiated invasive cancer cells. TIMP1 mRNA expression was detected in noninvasive and well-differentiated invasive tumor cells (Polette M. et al., 1993).

- A single nucleotide polymorphism has bbeen found at -1607 bp in the MMP1 promoter, where an insertion of a guanine (G) base creates the sequence 5'-GGAT-3', the core binding site for members of the Ets family of transcription factors. Genotyping of 100 normal individuals indicated that the distribution of this SNP in the normal population is appproximately : 30% = 1G homozygous; 30% = 2G homozygous; and 40% = 1G/2G heterozygous. However, in tumour cells cultured in vitro, the incidence of 2G allele rises to 62% (P<=0.001), supporting the hypothesis that it correlates with aggressive tumours (Rutter J.L. et al., 1998; see also Gilles C. et al., 1997).

- Immunoreactivity for MMP1 was detectedd in 59/77 (77%) breast carcinomas. MMP1 immunoreactivity in stromal fibroblasts but not in cancer cells showed a statistically significant correlation with tumor stage (P=0.04). MMP1 reactivity either in stromal or in cancer cells showed a statistically significant inverse correlation with PgR expression (P=0.04 and P=0.04, respectively) (Nakopoulou L. et al., 1999).

- By substrate zymography, MMP1 was meassured in paired tumour and normal tissue samples from 43 breast cancer patients. Compared to MMP2, MMP3, and MMP9, MMP1 was the least expressed MMP. MMP1 was only expressed in 22% breast tumours, mainly in latent form, and was not found in normal breast tissue samples (Garbett E.A. et al., 1999).

- The expression patterns of MMP-1, -2, and -3 were determined by in situ hybridization in normal breast tissue (n=6), fibrocystic disease (n=20), five cases of which contained radial scars, lobular carcinoma in situ (CLIS; n=5), ductal carcinoma in situ (DCIS; n=9) and invasive carcinomas (n=24). Only a few cells displayed MMP-1- and MMP-2-specific labeling in normal breast tissue and fibrocystic disease. Noninvasive ductal carcinomas showed elevated MMP-2 transcript levels in peritumor stromal cells in the absence of significant MMP-1 specific signals. In general, compared with adjacent normal breast tissue, a gradual increase of MMP-2 was found in noninvasive to invasive cancers. Invasive ductal and lobular carcinomas displayed co-expression of MMP-1 and MMP-2 by stromal cells, mainly of the invasion front, with high signal intensity particularly in high-grade invasive carcinomas. Tumor cells and peritumor stroma showed low MMP-3 transcript levels, especially in medullary carcinomas (Brummer O. et al., 1999).

- In primary breast cancers, TIMP-1 leveels were found to be weakly but significantly correlated with those for MMP1, proMMP2, active MMP2, MMP3 and proMMP9 (McCarthy K. et al., 1999).

- Thirty one specimens of bone metastasiis from breast carcinoma were stained for MMP1, 2, 9, 14 (MT1-MMP) and TIMP1, and 2 and compared with staining in normal breast tissue, primary breast carcinoma and normal bone. No major differences in the MMP/TIMP staining of tumor cells and fibroblasts were observed between bone metastasis and primary tumor. The number and activity of osteoclasts and osteoblasts was increased dramatically in bone metastases, their MMP/TIMP profiles, however, were not different from normal bone, suggesting that the mechanism of bone degradation by osteoclasts is not different from normal bone remodelling (Lhotak S. et al., 2000).

- The Ets-1 transcription factor transacctivates several genes encoding matrix-degrading proteases and is thought to be involved in both tumour vascularization and invasion. During breast cancer formation, as shown by in situ hybridization and immunohistochemistry, the Ets-1, MMP1, and MMP9 genes were first expressed within both endothelial cells and stromal fibroblasts during the onset of stroma generation around intraductal and intralobular in situ carcinomas and they were significantly up-regulated in the stroma of invasive ductal and lobular cancers (Behrens P. et al., 2001).

Balduyck M. et al. (2000) Specific expression of matrix metalloproteinases 1, 3, 9 and 13 associated with invasiveness of breast cancer cells in vitro. Clin. Exp. Metastasis 18, 171-178. (PubMed)
Behrens P. et al. (2001) The Ets-1 transcription factor is up-regulated together with MMP 1 and MMP 9 in the stroma of pre-invasive breast cancer. J. Pathol. 194, 43-50. (PubMed)
Benbow U. et al. (1999a) Human breast cancer cells activate procollagenase-1 and invade type I collagen: invasion is inhibited by all-trans retinoic acid. Clin. Exp. Metastasis 17, 231-238. (PubMed)
Benbow U. et al. (1999b) Transcriptional repression of the human collagenase-1 (MMP-1) gene in MDA231 breast cancer cells by all-trans-retinoic acid requires distal regions of the promoter. Br. J. Cancer 79, 221-228. (PubMed)
Borden P. and Heller R.A. (1997) Transcriptional control of matrix metalloproteinases and the tissue inhibitors of matrix metalloproteinases. Crit. Rev. Eukaryotic Gene Expression 7, 159-178 (Review). (PubMed)
Brinckerhoff C.E. et al. (1987) Molecular cloning of human synovial cell collagenase and selection of a single gene from genomic DNA. J. Clin. Invest. 79, 542-546. (PubMed)
Brinckerhoff C.E. et al. (2000) Interstitial collagenases as markers of tumor progression. Clin. Cancer Res. 6, 4823-4830 (Review). (PubMed)
Brummer O. et al. (1999) Matrix-metalloproteinases 1, 2, and 3 and their tissue inhibitors 1 and 2 in benign and malignant breast lesions: an in situ hybridization study. Virchows Arch. 435, 566-573. (PubMed)
Chambers A.F. and Matrisian L.A. Changing views on the role of matrix metalloproteinases in metastasis. J. Natl. Cancer Inst. 89, 1260-1270. (PubMed)
Garbett E.A. et al. (1999) Proteolysis in human breast and colorectal cancer. Br. J. Cancer 81, 287-293. (PubMed)
Gilles C. et al. (1997) Expression of c-ets-1 mRNA is associated with an invasive, EMT-derived phenotype in breast carcinoma cell lines. Clin. Exp. Metastasis 15, 519-526. (PubMed)
Goldberg G.I. et al. (1986) Human fibroblast collagenase: complete primary structure and homology to an oncogene transformation-induced rat protein. J. Biol. Chem. 261, 6600-6605. (PubMed)
Kleiner D.E. and Stetler-Stevenson W.G. (1999) Matrix metalloproteinases and metastasis. Cancer Chemother. Pharmacol. 43, S42-S51 (Review). (PubMed)
Ito A. et al. (1995) Co-culture of human breast adenocarcinoma MCF-7 cells and human dermal fibroblasts enhances the production of matrix metalloproteinases 1, 2 and 3 in fibroblasts. Br. J. Cancer 71, 1039-1045.(PubMed)
Lhotak S. et al. (2000) Immunolocalization of matrix metalloproteinases and their inhibitors in clinical specimens of bone metastasis from breast carcinoma. Clin. Exp. Metastasis 18, 463-470. (PubMed)
McCarthy K. et al. (1999) High levels of tissue inhibitor of metalloproteinase-1 predict poor outcome in patients with breast cancer. Int. J. Cancer 84, 44-48. (PubMed)
Nakopoulou L. et al. (1999) Matrix metalloproteinase-1 and -3 in breast cancer: correlation with progesterone receptors and other clinicopathologic features. Hum. Pathol. 30, 436-442. (PubMed)
Nutt J.E. and Lunec J. (1996) Induction of metalloproteinase (MMP1) expression by epidermal growth factor (EGF) receptor stimulation and serum deprivation in human breast tumour cells. Eur. J. Cancer 32A, 2127-2135. (PubMed)
Pendas A.M. et al. (1996) Fine physical mapping of the human matrix metalloproteinase genes clustered on chromosome 11q22.3. Genomics 37, 266-269. (PubMed)
Polette M. et al. (1993) Detection and localization of mRNAs encoding matrix metalloproteinases and their tissue inhibitor in human breast pathology. Invasion Metastasis 13, 31-37. (PubMed)
Ree A.H. et al. (1996) Regulation of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in MCF-7 cells: comparison with regulatory mechanisms of pS2 expression. Clin. Exp. Metastasis 14, 381-388. (PubMed)
Rutter J. et al. (1998) A single nucleotide polymorphism in the matrix metalloproteinase-1 promoter creates an Ets binding site and augments transcription. Cancer Res. 58, 5321-5325. (PubMed)
Saad S. et al. (2000) Induction of matrix metalloproteinases MMP-1 and MMP-2 by co-culture of breast cancer cells and bone marrow fibroblasts. Breast Cancer Res. Treat. 63, 105-115. (PubMed)
Sun J. and Hemler M.E. (2001) Regulation of MMP-1 and MMP-2 production through CD147/extracellular matrix metalloproteinase inducer interactions. Cancer Res. 61, 2276-2281. (PubMed)
Templeton N.S. et al. (1990) Cloning and characterization of human tumor cell interstitial collagenase. Cancer Res. 50, 5431-5437. (PubMed)
Turton N.J. et al. (2001) Gene expression and amplification in breast carcinoma cells with intrinsic and acquired doxorubicin resistance. Oncogene 20, 1300-1306. (PubMed)
Watabe T. et al. (1998) The Ets-1 and Ets-2 transcription factors activate the promoters for invasion-associated urokinase and collagenase genes in response to epidermal growth factor. Int. J. Cancer 77, 128-137. (PubMed)

Genome Database data (GDB Access Number: 119783)
GeneCard data (MMP1)
UniGene data (Hs.83169)
OMIM data (ID = 120353)
LocusLink data (LocusID = 4312)
Swiss-Prot (ID = P03956)


MMP2, MMP3, MMP7, MMP9, MMP11, MMP13, MMP14, MMP15, MMP16, MMP17, TIMP1, TIMP2, TIMP3, TIMP4