Different expression patterns of MMP-2 and MMP-9 in breast cancer

Comparative iTRAQ proteomics revealed proteins associated with lobed fin regeneration in Bichirs

Background

Polypterus senegalus can fully regenerate its pectoral lobed fins, including a complex endoskeleton, with remarkable precision. However, despite the enormous potential of this species for use in medical research, its regeneration mechanisms remain largely unknown.

Methods

To identify the differentially expressed proteins (DEPs) during the early stages of lobed fin regeneration in P. senegalus, we performed a differential proteomic analysis using isobaric tag for relative and absolute quantitation (iTRAQ) approach based quantitative proteome from the pectoral lobed fins at 3 time points. Furthermore, we validated the changes in protein expression with multiple-reaction monitoring (MRM) analysis.

Results

The experiment yielded a total of 3177 proteins and 15,091 unique peptides including 1006 non-redundant (nr) DEPs. Of these, 592 were upregulated while 349 were downregulated after lobed fin amputation when compared to the original tissue. Bioinformatics analyses showed that the DEPs were mainly associated with Ribosome and RNA transport, metabolic, ECM-receptor interaction, Golgi and endoplasmic reticulum, DNA replication, and Regulation of actin cytoskeleton.

Conclusions

To our knowledge, this is the first proteomic research to investigate alterations in protein levels and affected pathways in bichirs’ lobe-fin/limb regeneration. In addition, our study demonstrated a highly dynamic regulation during lobed fin regeneration in P. senegalus. These results not only provide a comprehensive dataset on differentially expressed proteins during the early stages of lobe-fin/limb regeneration but also advance our understanding of the molecular mechanisms underlying lobe-fin/limb regeneration.

Serum TIMP-1 and response to the aromatase inhibitor letrozole versus tamoxifen in metastatic breast cancer

PURPOSE

To determine the effect of elevated serum TIMP-1 on the response of patients with metastatic breast cancer to an aromatase inhibitor versus tamoxifen.

PATIENTS AND METHODS

Five hundred twenty-two patients estrogen receptor-positive metastatic breast cancer were randomly assigned to receive first-line hormone therapy with letrozole or tamoxifen. Serum tissue inhibitor of metalloproteinases-1 (TIMP-1) levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Pretreatment serum TIMP-1 was elevated in 120 (23%) of 522 patients. Patients with elevated serum TIMP-1 had a significantly reduced objective response rate (19.2% v 30.6%; odds ratio, 0.54; P = .01), duration of response (median, 15.5 v 26.2 months; P = .001), time to treatment progression (TTP; median, 4.5 v 9.2 months; HR, 1.78; P = .0001), time to treatment failure (median, 3.5 v 9.0 months; HR, 1.77; P = .0001), and overall survival (median, 20.3 v 35.8 months; HR, 1.77; P = .0001) compared with patients with normal pretreatment TIMP-1 levels. Letrozole was superior to tamoxifen in both the normal serum TIMP-1 group (median TTP, 11.8 v 8.6 months; P = .003) and in the elevated serum TIMP-1 group (median, 6.1 v 3.2 months; P = .03) In multivariate analysis, elevated serum TIMP-1 remained an independent predictor of both shorter TTP (HR, 1.46; P = .002) and survival (HR, 1.44; P = .002), as did serum HER-2. Combined analysis of both serum TIMP-1 and HER-2/neu conferred additional ability to predict significantly different clinical outcomes compared to using either biomarker alone.

CONCLUSION

Patients with elevated pretreatment serum TIMP-1 had a significantly reduced response and survival. Serum TIMP-1 was an independent predictive and prognostic factor. Blockade of TIMP-1 and HER-2/neu activity may be beneficial in a subset of patients with breast cancer.

A human breast cell model of preinvasive to invasive transition

A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from preinvasive to invasive phenotype as it may occur "spontaneously" in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted basement membrane cultures. These cells remained noninvasive; however, unlike their nonmalignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher-grade tumors. To find functionally significant changes in transition from preinvasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between preinvasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP9, MMP13, MMP15, and MMP17 was up-regulated in the invasive cells. Using small interfering RNA-based approaches, we found these MMPs to be required for the invasive phenotype. This model provides a new tool for dissection of mechanisms by which preinvasive breast cells could acquire invasiveness in a metaplastic context.

Expression of MT-1 MMP, MMP2, MMP9 and TIMP2 mRNAs in ductal carcinoma in situ and invasive ductal carcinoma of the breast

We investigated the expression of membrane type-1 (MT1)-MMP, MMP2, MMP9 and TIMP2 mRNAs and their roles in ductal carcinoma in situ (DCIS) and T1 and T2 invasive ductal carcinoma of the breast. We further compared these two types of carcinomas for differences in microvessel density, and expression of angiogenic factors and CD44std. MT1-MMP, MMP2, MMP9 and TIMP2 mRNA were expressed in both DCIS and invasive ductal carcinomas. Expression rates of MT1-MMP, MMP2, MMP9 and TIMP2 mRNAs were not statistically different between DCIS and invasive ductal carcinomas, nor did they differ statistically when grouped by tumor size, histologic grade or nuclear grade of invasive ductal carcinoma. Microvessel density and expression of VEGF and TGF-beta1 were not statistically different between DCIS and invasive ductal carcinoma. CD44std expression was significantly increased in DCIS compared to invasive ductal carcinoma (p < 0.05) and it was also significantly increased in lower clinical stage, histologic grade and nuclear grade of invasive ductal carcinoma (p < 0.05). Axillary node metastasis was significantly correlated with MT1-MMP mRNA, VEGF and TGF-beta1 expression (p < 0.05) and MT1-MMP mRNA was positively correlated with VEGF expression and TIMP2 mRNA (p < 0.05). In summary, patterns of MMP mRNA expression in DCIS and invasive ductal carcinoma suggest that the invasive potential of breast carcinoma is already achieved before morphologically overt invasive growth is observed. As MT1-MMP mRNA expression is significantly correlated with axillary nodal metastasis, it may be useful as a prognostic indicator of invasive ductal carcinoma. Considering the positive correlation of MT1-MMP mRNA and TIMP2mRNA expression, our finding supports a role for TIMP2 in tumor growth, as well as the utility of CD44std as a prognostic indicator of breast cancer.

The activity of matrix metalloproteinases (MMPS) and tissue inhibitors of metalloproteinases (TIMPs) in mammary tumors of dogs and rats

We conducted zymography for detecting the activity of matrix metalloproteinases (MMPs) and reverse zymography for the activity of tissue inhibitors of metalloproteinases (TIMPs) in canine spontaneous and rat 7, 12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumor tissues. The activities of MMPs of canine mammary tumors were quite higher than those of the rat chemically induced tumors. The activities of MMPs were significantly higher in malignant tissues than in benign ones of canine tumors, whereas the activity of only MMP-2 was higher in both benign and malignant rat tumors compared to normal tissues. There were no differences of MMPs activities between benign and malignant rat tumors. The results of reverse zymography indicated that the activities of TIMP-1, -2 and -3 were strikingly higher in rat tumors than in canine tumors. The activities were higher in malignant tissues than in benign ones of dogs, and higher in tumor tissues than in normal mammary tissues of rats. The results of film in situ zymography for tissue localization of gelatinolytic activity showed that the digested area was more extended in malignant tumors than in benign ones of dogs. However, the area was similarly extended in both benign and malignant rat tumors. These results may indicate that the canine spontaneous malignant mammary tumors possess more aggressive nature than the rat chemically induced counterpart, resulting from the high level of MMPs and low level of TIMPs activities of the tumor tissues.

MMP-9 and MMP-2 gelatinases and TIMP-1 and TIMP-2 inhibitors in breast cancer: correlations with prognostic factors

The goal of our study was to analyse the prognostic values for some matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in breast cancer. We evaluated the activity and the expression levels of MMP-9, MMP-2, TIMP-1 and TIMP-2 in malignant versus benign fresh breast tumor extracts. For this purpose, gelatinzymography, immunoblotting and ELISA were used to analyse the activity and expression of MMPs and TIMPs. We found that MMP-9 expression level and activity are increased in malignant tumors. In addition, MMP-9/TIMP-1 and MMP-2/TIMP-2 ratio values obtained by us were significantly different in malignant tumors compared to benign tumors. We suggest that the abnormal MMP-9/TIMP-1 balance plays a role in the configuration of breast invasive carcinoma of no special type and also in tumor growth, while altered MMP-2/TIMP-2 ratio value could be associated with lymph node invasion and used as a prognostic marker in correlation with Nottingham Prognostic Index. Finally, we showed that in malignant tumors high expression of estrogen receptors is associated with enhanced activity of MMP-2 and increased bcl- 2 levels, while high expression of progesterone receptors is correlated with low TIMP-1 protein levels.

Overexpression of matrix-metalloproteinase-9 in human breast cancer: a potential favourable indicator in node-negative patients

Matrix metalloprotease-9 (MMP-9; 92 kDa type IV collaganase, gelatinase B) is regarded as, important for degradation of the basement membrane and extracellular matrix during cancer invasion and other tissue-remodelling events. In this study we evaluate the prognostic value of MMP-9, by immunoperoxidase staining in a series of 210 breast cancer tissues. The results were quantitated using the HSCORE system, which consider both staining intensity and the percentage of cells stained at given intensities. MMP-9 status was compared with the concentration of cytosolic Cathepsin-D and with other established prognostic factors, in terms of disease free survival and overall survival. The median follow-up period was 62 months. MMP-9 staining was observed primarily in cancer cells, and to a lesser degree in surrounding stromal cells. MMP-9 expression was not detected in normal breast tissue. Levels of MMP-9 expression below the cut-off point were more frequently observed in larger (P = 0.014), invasive ductal histologic (P = 0.037), progesterone receptor (PR)-negative and PR-strong positive tumours (P< 0.001), as well as samples belonging to patients with stage III-IV disease (P = 0.009) and age 45-55 years (P = 0.011). In univariate analysis, node-negative breast cancer patients with tumors positive for MMP-9 had a considerable reduction in risk for relapse (RR = 0.45;P = 0.039) or death (RR = 0.32;P = 0.009). Multivariate analysis indicated that MMP-9 status was an independent favourable predictor of OS (RR = 0.47;P = 0.034) in node-negative but not in node-positive patients. Our results suggest that MMP-9 may be an independent favourable prognostic factor in node-negative breast cancer patients. The overexpression of MMP-9 in breast cancer may be also used as a marker to subdivide node negative breast cancer patients in order to determine the optimal treatment modality.

Matrix metalloproteinase 9 promoter activity is induced coincident with invasion during tumor progression

Matrix metalloproteinase 9 (MMP-9, also known as gelatinase B or 92-kd Type IV collagenase) is overexpressed in many human and murine cancers. We induced carcinomas in mice carrying a transgene that links the MMP-9 promoter to the reporter ss-galactosidase so that activation of the MMP-9 promoter would be indicated by ss-galactosidase. Mammary carcinomas were induced by mating the MMP-9 promoter reporter transgenic mice with mice carrying a transgene for murine mammary tumor virus promoter linked to polyoma middle T antigen, a transgene that leads to rapid development of mammary tumors in female mice. None of the hyperplastic mammary glands and none of the carcinomas in situ expressed ss-galactosidase. However, all invasive tumors had evidence of ss-galactosidase expression. In addition to the breast carcinomas, a malignant teratoma in a female and a papillary adenocarcinoma in the pelvic region of a male arose and were also ss-galactosidase positive. We also induced skin tumors in the mice with the MMP-9 reporter transgene with 7, 12-dimethylbenz[a]anthracene (DMBA) treatment followed by phorbol 12 myristate 13-acetate (TPA). None of the papillomas or in situ carcinomas showed any ss-galactosidase expression, but expression was seen in invasive carcinoma. Although normal skin epithelial cells did not express ss-galactosidase, we did find staining in a few cells at the duct of the sebaceous gland at the base of the hair follicles. The MMP-9 reporter transgene did not lead to expression in the alveolar macrophages, confirming that additional upstream sequences are required for expression in macrophages. These experiments have revealed that MMP-9 promoter activity is induced coincident with invasion during tumor progression. Furthermore, this indicates that the more proximal upstream elements of the promoter are sufficient for MMP-9 transcription during tumor progression.

Matrix metalloproteinases: biologic activity and clinical implications

Tumor progression is a complex, multistage process by which a normal cell undergoes genetic changes that result in phenotypic alterations and the acquisition of the ability to spread and colonize distant sites in the body. Although many factors regulate malignant tumor growth and spread, interactions between a tumor and its surrounding microenvironment result in the production of important protein products that are crucial to each step of tumor progression. The matrix metalloproteinases (MMPs) are a family of degradative enzymes with clear links to malignancy. These enzymes are associated with tumor cell invasion of the basement membrane and stroma, blood vessel penetration, and metastasis. They have more recently been implicated in primary and metastatic tumor growth and angiogenesis, and they may even have a role in tumor promotion. This review outlines our current understanding of the MMP family, including the association of particular MMPs with malignant phenotypes and the role of MMPs in specific steps of the metastatic cascade. As scientific understanding of the MMPs has advanced, therapeutic strategies that capitalize on blocking the enzymes have rapidly developed. The preclinical and clinical evolution of the synthetic MMP inhibitors (MMPIs) is also examined, with the discussion encompassing important methodologic issues associated with determining clinical efficacy of MMPIs and other novel therapeutic agents.