Matrix metalloproteinase-14
(MMP14, MMP-14)

Membrane-type matrix metalloproteinase-1 (MT-MMP-1, MT-MMP1, MT1-MMP)

Gene: MMP14 maps to 14q11-q12.
mRNA: size: ? kb.
Protein: a 582-amino acid polypeptide with conserved sequence and a similar domain structure to other MMPs. However, like other membrane-type MMPs, MMP14 exhibits a unique transmembrane domain at the C terminus and is therefore a spanning protein rather than a secretory protein. MMP14 is the most potent activator of MMP2.
See also: structural and functional characteristics of MMPs

Cell lines:
- In MDA-MB-231 breast cancer cells (BCCC), it was demonstrated that MMP14 is secreted from cells in a complex with TIMP2, which can form a ternary complex of MMP14/TIMP2/proMMP2 (Imai K. et al., 1996).

. - The ability of two different BCC liness, one non-invasive (MCF7) and one invasive (MDA-MB-231) to stimulate MMP14 production in human fibroblasts with consequent proMMP2-activation. The MDA-MB-231 conditioned medium induced MMP14 mRNAs in human fibroblasts and a parallel activation of proMMP2 whereas MCF7 conditioned medium did not have any effect (Polette M. et al., 1997).

- Northern analysis revealed baseline exxpression of MMP14 in 5/6 vimentin-positive (VIM+) BCC lines studied (MDA-MB-231, MDA-MB-435, BT-549, Hs578T, MCF-7(ADR)), each of which showed variable activation of exogenous MMP2 after treatment with concanavalin A (Con A). In contrast, the 4 vimentin-negative (VIM-), poorly invasive BCC lines studied (MCF-7, T47D, MDA-MB 468, ZR-75-1) lacked baseline MMP14 mRNA expression, and showed no induction of either MMP14 expression or MMP2-activation with Con A. Such differential MMP14 expression was confirmed in vivo using in situ hybridization analysis of nude mouse tumor xenografts of representative BCC lines. Western analysis of the MDA-MB-231 cells revealed baseline membrane expression of a 60 kDa species, which was strongly induced by Con A treatment along with a weaker band co-migrating with that from MMP14-transfected COS-1 cells (63 kDa), presumably representing latent MMP14. MMP14 immunofluorescence strongly decorated Con A-stimulated MDA-MB-231 cells in a manner consistent with membranous staining, but did not decorate the unstimulated MDA-MB-231 cells or MCF-7 cells under either condition (Pulyaeva H. et al., 1997).

- Treatment with collagen type I increassed the steady-state MMP14 mRNA levels in invasive BCC but did not induce either MMP14 expression or MMP2 activation in noninvasive BCC lines, which retain epithelial features. Basal MT3-MMP (MMP16) mRNA expression had a pattern similar to that of MMP14 but was not up-regulated by collagen. MT4-MMP (MMP17) mRNA was seen in both invasive and noninvasive BCC lines and was also not collagen-regulated, and MT2-MMP (MMP15) mRNA was not detected in any of the BCC lines tested. In situ hybridization analysis of archival breast cancer specimens revealed a close parallel in expression of both collagen type I and MMP14 mRNA in peritumoral fibroblasts, which was correlated with aggressiveness of the lesion. Relatively high levels of expression of both mRNA species were seen in fibroblasts close to invasive tumor nests and, although only focally, in certain areas close to preinvasive tumors (Gilles C. et al., 1997).

- MMP14 expression and pro-MMP2 activatiion were stimulated by concanavalin A in two BCC lines (BT549 and MDA-MB-231) and were slightly upregulated by breast cancer cell-fibroblast interactions. Both pro-MMP14 in plasma membrane (63.4 kDa) and the soluble forms of the enzyme in culture medium (57.6 and 25-30 kDa) were detected by immunoblot analysis, suggesting that cell-surface MMP14 exhibits an active conformation without the removal of its propeptide domain and that the mature enzyme is shed into the medium. In breast cancer cells, MMP14 and a recombinant catalytic domain of MMP14 were unable to activate pro-matrilysin (pro-MMP7), indicating that MMP14 is not a universal activator of all MMPs. MMP14 could play an important role in the invasive growth and spread of breast cancer cells by specifically activating pro-MMP2 to cleave the connective-tissue barrier (Li H. et al., 1998).

- It was found that three different cAMPP-inducing agents, cholera toxin (CT), forskolin (FSK), and 3-isobutyl-1-methylxanthine (IBMX) partially inhibited Concanavalin A (ConA)-induced MMP14 expression and MMP2 activation in MDA-MB-231 cells. Combinations of CT or FSK with IBMX exhibited additive effects on reduction of MMP14 mRNA expression and MMP2 activation. Agents which increase cAMP levels appeared to target transcriptional aspects of ConA induction, reducing MMP14 mRNA and protein in parallel with the reduced MMP2 activation. In the absence of ConA, down-regulation of constitutive production of MMP14 mRNA and protein was observed, indicating that cAMP acts independently of ConA (Yu M. et al., 1998).

- Osteonectin (OSN) was able to induce MMMP2 activation in two invasive BCC lines (MDA-MB-231 and BT549) but not in a noninvasive counterpart (MCF-7), which lacks MMP14. Using a set of peptides from different regions of OSN, it was found that peptide 1.1 (corresponding to the NH2-terminal region of the protein) contained the activity that induced MMP2 activation. Despite the requirement for MMP14, seen in MCF-7 BCC transfected with MMP14, the activation of MMP2 by OSN peptide 1.1 was not associated with increased steady-state levels of MMP14 mRNA or protein in either MMP14-transfected MCF-7 cells or constitutively expressing MDA-MB-231 and BT549 cells (Gilles C. et al., 1998).

- MMP14 cleaves the N-terminal prodomainn of pro-MMP2 thus generating the activation intermediate that then matures into the fully active enzyme of MMP2. It was found that coexpression of MMP14 and integrin alpha_Vbeta₃ in MCF-7 BCC specifically enhance in trans autocatalytic maturation of MMP2. The association of MMP2's C-terminal hemopexin-like domain with those molecules of integrin alpha_Vbeta₃ which are proximal to MMP14 facilitates MMP2 maturation. Vitronectin, a specific ligand of integrin alpha_Vbeta₃, competitively blocked the integrin-dependent maturation of MMP2. Immunofluorescence and immunoprecipitation studies supported clustering of MMP14 and integrin alpha_Vbeta₃ at discrete regions of the cell surface (Deryugina E.I. et al., 2001).

Tumors:
- In situ hybridisation revealed MMP14 transcripts distributed principally in stromal cells in close contact to tumour clusters in breast carcinomas (16 cases studied). Northern blot analysis showed a parallel expression of MMP14 and MMP2 transcripts in breast cancers. Immunohistochemistry displayed a more extensive distribution of MMP14 in mammary carcinomas with numerous labelled preinvasive and infiltrating cancer cells and stromal cells near the tumour cells (Polette M. et al., 1996).

- In breast carcinomas, MMP2 and MMP14 eexhibit quite similar patterns of expression. At the cellular level, MMP14 mRNA is predominantly detected in fibroblastic cells of carcinomas (Okada A. et al., 1995, Heppner K.J. et al., 1996).

- Northern blot analysis demonstrated thhe predominant expression of MMP14 mRNA in carcinoma tissues (20 of 20 cases), whereas MMP15 (MT2-MMP) was detected in only 25% of the cases (5 of 20 cases), and no detectable expression of MMP16 (MT3-MMP) was observed. The expression levels of MMP14 but not MMP15 correlated well with the presence of lymph node and distant metastases, clinical stages, and size of tumors. Immunohistochemically, MMP14 was localized predominantly in the carcinoma cells in all of the samples (32 of 32 cases). Immunostaining of MMP15 in the carcinoma cells was observed in only 38% of the cases (12 of 32 cases). Immunoblot analysis of tumor homogenates confirmed the presence of these MMPs (Ueno H. et al., 1997).

- The expression and cellular localizatiion of MMP14 was investigated in breast carcinomas using monoclonal antibodies directed against 3 different epitopes of MMP14. MMP14 was present in 25/25 breast carcinomas tested, as well as in 19 adenocarcinomas of various organs (colon, duodenum, stomach, pancreas, ovary, lung). At the cellular level, with the exception of 1 breast carcinoma showing weak staining in cancer cells associated with strong staining of stromal cells, MMP14 immunostaining was always restricted to stromal fibroblastic cells, throughout the tumor (Chenard M.-P. et al., 1999).

- MMP14 expression in human breast tumorrs was investigated by immunocytochemical assay, and its correlation with clinicobiological features was analyzed. MMP14 expression was detected in tumor cells and/or stromal cells, and there was a strong correlation between the expressions of MMP14 in the two cell types. Out of 183 primary tumors, 103 (56.2%) showed positive staining of MMP14 in tumor cells. MMP14 expression showed no significant correlation with any of the clinicobiological parameters examined, including hormone receptor status and angiogenesis. In postoperative survival analysis, MMP14 expression was not a significant prognostic factor (Ishigaki S. et al., 1999).

- MMP2, MMP14, and MMP9 expression was sstudied by immunohistochemistry in a series of 79 infiltrating ductal carcinomas (IDCs), 8 tubular carcinomas, and 27 infiltrating lobular carcinomas (ILCs). MMP2 and MMP14 were expressed in more than 90 per cent of all carcinomas, with predominantly stromal and tumour cell cytoplasmic staining. However, reactivity localized on tumour cell membranes was recorded for MMP2 in 34 per cent of cases with a monoclonal antibody and 55 per cent of cases with a polyclonal antibody, and for MMP14 in 68 per cent of tumours. MMP-9 was expressed by 68 per cent of carcinomas, either in the stromal compartment or by tumour cells. There was a highly significant correlation between the expression pattern of MMP9 and tumour type, with ILCs displaying greater frequency and more homogeneous cytoplasmic staining than IDCs (p=0.0004) (Jones J.L. 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).

- EMMPRIN (CD147, basigin) is thought too stimulate fibroblasts to produce the zymogen pro-MMP2. MMP14 is thought to assist in tumor invasion and metastasis by activating pro-MMP2. The mRNA expression pattern of MMP14, MMP2, and EMMPRIN was studied in 18 breast tumor samples by in situ hybridization. MMP2, MMP14, and EMMPRIN mRNA expression were detected in all of the carcinomas. The MMP2 mRNA expression was mainly localized to stromal cells at moderate to high levels surrounding the invading carcinoma cells but was also seen in single cells at low levels in in situ lesions and in some normal glandular cells. MMP14 and EMMPRIN were expressed in all of the carcinomas and were mainly localized to tumor cells; but they were also seen to some extent in single cells at low levels in in situ lesions and in normal glandular cells. No differences in levels of expression for MMP2, MMP14, or EMMPRIN were seen in patients who survived compared to patients who died from metastatic disease (Dalberg K. et al., 2000).

- The clinicopathologic significance of the expression of MMP14 mRNA was examined in 53 breast cancer specimens by the semiquantitative RT-PCR assay. The highest expression of MMP14 was found in those specimens showing lymph node metastasis and/or lymph vessel invasion (Mimori K. et al., 2001).

Chenard M.-P. et al. (1999) Presence of high levels of MT1-MMP protein in fibroblastic cells of human invasive carcinomas. Int. J. Cancer 82, 208-212. (PubMed)
Dalberg K. et al. (2000) Gelatinase A, membrane type 1 matrix metalloproteinase, and extracellular matrix metalloproteinase inducer mRNA expression: correlation with invasive growth of breast cancer. World J. Surg. 24, 334-340. (PubMed)
Deryugina E.I. et al. (2001) MT1-MMP initiates activation of pro-MMP-2 and integrin alphavbeta3 promotes maturation of MMP-2 in breast carcinoma cells. Exp. Cell. Res. 263, 209-223. (PubMed)
Gilles C. et al. (1997) Implication of collagen type I-induced membrane-type 1-matrix metalloproteinase expression and matrix metalloproteinase-2 activation in the metastatic progression of breast carcinoma. Lab. Invest. 76, 651-660. (PubMed)
Gilles C. et al. (1998) SPARC/osteonectin induces matrix metalloproteinase 2 activation in human breast cancer cell lines. Cancer Res. 58, 5529-5536. (PubMed)
Heppner K.J. et al. (1996) Expression of most matrix metalloproteinase family members in breast cancer represents a tumor-induced host response. Am. J. Pathol. 149, 273-282. (PubMed)
Imai K. et al. (1996) Membrane-type matrix metalloproteinase 1 is a gelatinolytic enzyme and is secreted in a complex with tissue inhibitor of metalloproteinases 2. Cancer Res. 56, 2707-2710. (PubMed)
Ishigaki S. et al. (1999) Significance of membrane type 1 matrix metalloproteinase expression in breast cancer. Jpn. J. Cancer Res. 90, 516-522. (PubMed)
Jones J.L. et al. (1999) Expression of MMP-2 and MMP-9, their inhibitors, and the activator MT1-MMP in primary breast carcinomas. J. Pathol. 189, 161-168. (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)
Li H. et al. (1998) Immunological characterization of cell-surface and soluble forms of membrane type 1 matrix metalloproteinase in human breast cancer cells and in fibroblasts. Mol. Carcinog. 22, 84-94. (PubMed)
Mignon C. et al. (1995) Assignment of the human membrane-type matrix metalloproteinase (MMP14) gene to 14q11-q12 by in situ hybridization. Genomics 28, 360-361. (PubMed)
Mimori K. et al. (2001) Clinical significance of MT1-MMP mRNA expression in breast cancer. Oncol. Rep. 8, 401-403. (PubMed)
Okada A. et al. (1995) Membrane-type matrix metalloproteinase (MT1-MMP) gene is expressed in stromal cells of human colon, breast, and head and neck carcinomas. Proc. Natl. Acad. Sci. USA 92, 2730-2734. (PubMed)
Polette M. et al. (1996) MT-MMP expression and localisation in human lung and breast cancers. Virchows Arch. 428, 29-35. (PubMed)
Polette M. et al. (1997) Induction of membrane-type matrix metalloproteinase 1 (MT1-MMP) expression in human fibroblasts by breast adenocarcinoma cells. Clin. Exp. Metastasis 15, 157-163. (PubMed)
Pulyaeva H. et al. (1997) MT1-MMP correlates with MMP-2 activation potential seen after epithelial to mesenchymal transition in human breast carcinoma cells. Clin. Exp. Metastasis 15, 111-120. (PubMed)
Sato H. et al. (1994) A matrix metalloproteinase expressed on the surface of invasive tumor cells. Nature 370, 61-65. (PubMed)
Takino T. et al. (1995) Cloning of a human gene potentially encoding a novel matrix metalloproteinase having a C-terminal transmembrane domain. Gene 155, 293-298. (PubMed)
Ueno H. et al. (1997) Expression and tissue localization of membrane-type 1, 2, and 3 matrix metalloproteinases in human invasive breast carcinomas. Cancer Res. 57, 2055-2060. (PubMed)
Yu M. et al. (1998) Elevated cyclic AMP suppresses ConA-induced MT1-MMP expression in MDA-MB-231 human breast cancer cells. Clin. Exp. Metastasis 16, 185-191. (PubMed)

Genome Database data (GDB Access Number: 375731)
GeneCard data (MMP14)
UniGene data (Hs.2399)
OMIM data (ID = 600754)
LocusLink data (LocusID = 4323)
Swiss-Prot (ID = P50281)


MMP1, MMP2, MMP3, MMP7, MMP9, MMP11, MMP13, MMP15, MMP16, MMP17, TIMP1, TIMP2, TIMP3, TIMP4