Polymorphisms of the promoter regions of matrix metalloproteinases genes MMP-1 and MMP-9 in breast cancer

Matrix metalloproteinase gene polymorphisms and oral cancer

Since oral squamous cell carcinoma (OSCC) is the most prevalent malignant cancer in the oral cavity, several researches have been performed to study the role of important enzymes in this disease. Among them, the matrix metalloproteinases (MMPs) are highlighted, due to the fact that they are proteinases responsible to degrade many extra-cellular matrix components, making possible the invasion of neoplasic cells. Important tools in cancer prognosis have been utilized aiming to correlate high levels of MMPs and OSCC, such as immunohistochemical, zymographic and mRNA detection methods. However, these techniques are usually applied after cancer detection, characterizing a curative but not a preventive medicine. Trying to make interventions before the development of the disease and making possible the identification of people at high risk and, analysis of modifications in MMP genes has been a chance for modern medicine. Recently, polymorphisms in MMP genes have been related to different neoplasias, including OSCC. Despite investigation is beginning, MMP gene polymorphisms seems to have a promising future in oral cancer research and some of the present results have shown that there are MMP polymorphisms related to an increased risk for developing oral cancer. Key words:Oral cancer, polymorphism, matrix metalloproteinase.

The association between individual SNPs or haplotypes of matrix metalloproteinase 1 and gastric cancer susceptibility, progression and prognosis

Background

The single nucleotide polymorphisms (SNPs) in matrix metalloproteinase 1(MMP-1)play important roles in some cancers. This study examined the associations between individual SNPs or haplotypes in MMP-1 and susceptibility, clinicopathological parameters and prognosis of gastric cancer in a large sample of the Han population in northern China.

Methods

In this case–controlled study, there were 404 patients with gastric cancer and 404 healthy controls. Seven SNPs were genotyped using the MALDI-TOF MS system. Then, SPSS software, Haploview 4.2 software, Haplo.states software and THEsias software were used to estimate the association between individual SNPs or haplotypes of MMP-1 and gastric cancer susceptibility, progression and prognosis.

Results

Among seven SNPs, there were no individual SNPs correlated to gastric cancer risk. Moreover, only the rs470206 genotype had a correlation with histologic grades, and the patients with GA/AA had well cell differentiation compared to the patients with genotype GG (OR=0.573; 95%CI: 0.353–0.929; P=0.023). Then, we constructed a four-marker haplotype block that contained 4 common haplotypes: TCCG, GCCG, TTCG and TTTA. However, all four common haplotypes had no correlation with gastric cancer risk and we did not find any relationship between these haplotypes and clinicopathological parameters in gastric cancer. Furthermore, neither individual SNPs nor haplotypes had an association with the survival of patients with gastric cancer.

Conclusions

This study evaluated polymorphisms of the MMP-1 gene in gastric cancer with a MALDI-TOF MS method in a large northern Chinese case-controlled cohort. Our results indicated that these seven SNPs of MMP-1 might not be useful as significant markers to predict gastric cancer susceptibility, progression or prognosis, at least in the Han population in northern China.

Association of MMP8 gene variation with an increased risk of malignant melanoma

Matrix metalloproteinases (MMPs) are implicated in the development of cancers including malignant melanoma (MM) and breast cancer. We tested the possible association of MMP1 and MMP8 gene variation with these two types of cancer. We genotyped 300 unselected patients with MM, 300 consecutive breast cancer cases, 300 controls for melanoma, and 300 controls for breast cancer (age-matched and sex-matched healthy adults with negative cancer family histories). Our study showed that the MMP8 gene rs11225395 polymorphism was associated with the risk of developing MM (odds ratio: 1.69; 95% confidence interval: 1.02-2.80; P=0.040) for the A/A genotype and 1.49 (95% confidence interval: 1.03-2.17; P=0.035) for the A/G genotype compared with the G/G genotype. The A allele was over-represented among MM cases compared with controls (odds ratio=1.54; P=0.017). In-vitro assays showed that the A allele had a higher promoter activity than the G allele in melanoma cells. No association was detected between this variant and breast cancer susceptibility. We found no strong association between MMP1 variation and the risk of MM or breast cancer. The finding of this study indicates an influence of MMP8 gene variation on melanoma susceptibility.

Association between polymorphisms in the promoter regions of matrix metalloproteinases (MMPs) and risk of cancer metastasis: a meta-analysis

BACKGROUND

A variety of studies have evaluated the associations between polymorphisms in the promoter regions of Matrix metalloproteinases (MMPs) and cancer metastasis. However, the results remain inconclusive. To better understand the roles of MMP polymorphisms in metastasis, we conducted a comprehensive meta-analysis.

METHODS

Electronic databases were searched (from January 2000 to June 2011) for any MMP genetic association studies in metastasis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between MMP polymorphisms and metastasis. Statistical analysis was performed with Review Manager 5.0 and STATA11.0.

RESULTS

Thirty-three studies addressing five MMP polymorphisms were analyzed among 10,516 cancer cases (4,059 metastasis-positive cases and 6,457 metastasis-negative cases). For MMP1 (-1607)1G/2G, genotype 2G/2G increased the overall risk of metastasis under the recessive model (OR = 1.44, 95% CI = 1.05-1.98). In subgroup analysis based on cancer type, associations were found in head/neck and breast cancer under the recessive model, and also in breast cancer under the dominant model. For MMP3 (-1171) 5A/6A, the polymorphism decreased the overall risk of metastasis under two genetic models (recessive: OR = 0.80, 95%CI = 0.64-0.99, dominant: OR = 0.72, 95%CI = 0.56-0.93). The polymorphisms of MMP7 (-181) A/G and MMP9 (-1562) C/T increased metastatic risk. However, no association was observed between MMP2 (-1306) C/T and metastasis.

CONCLUSIONS

Our investigations demonstrate that polymorphisms in the promoter regions of MMP1, 3, 7 and 9 might be associated with metastasis in some cancers. Further studies with large sample size for MMP2 should be conducted.

Analysis of matrix metalloproteinase-1 gene polymorphisms and expression in benign and malignant breast tumors

A guanine insertion polymorphism in matrix metalloproteinase-1 promoter (MMP-1 2G) is linked to early onset and aggressiveness in cancer. We determined the role of MMP-1 2G on MMP-1 expression and breast cancer severity in patients with breast diseases. We observed no significant difference in genotype distribution among different disease groups. However, MMP-1 expression was significantly higher in atypical ductal hyperplasia than in benign breast disease and in invasive breast cancer compared to in situ breast cancer. MMP-1 2G insertion polymorphism in the invasive group also correlated significantly with the expression of MMP-1 and breast cancer prognostic markers HER2 and P53.

Amentoflavone inhibits UVB-induced matrix metalloproteinase-1 expression through the modulation of AP-1 components in normal human fibroblasts

Amentoflavone is a well-known biflavonoid that has diverse biological effects. Previously, we reported that amentoflavone suppressed UVB-induced matrix metalloproteinase-1 (MMP-1) expression in normal human fibroblasts (NHF). We investigated the effects of amentoflavone on UVB-induced MMP-1 expression in order to elucidate its mode of action. NHF were treated with amentoflavone for indicated times and doses with UVB irradiation. The expressions of MMP-1 gene and protein were determined by RT-PCR and ELISA, respectively. MAP kinase phosphorylation and the expression of c-Fos protein were determined by Western blot. The treatment of amentoflavone completely blocked the upregulation of MMP-1 which is induced by UVB irradiation in HaCaT-NHF co-culture in a dose-dependent manner as well as in NHF monoculture. Also, amentoflavone inhibited UVB-induced activation of extracellular signal-regulated kinase (ERK) without changing total ERK protein level, and did not affect p38 or JNK activation. Finally, AP-1 transcription factor components, phospho-c-Jun and c-Fos protein expressions were decreased by amentoflavone treatment. The major finding of this study shows that amentoflavone inhibits intracellular cell signaling ERK pathway leading to the prevention of MMP-1 expression in human skin fibroblasts. Therefore, these results strongly suggest that amentoflavone should be investigated as a potential agent for the prevention and the treatment of skin photoaging.

MMP-1 expression has an independent prognostic value in breast cancer

Background

Breast cancer consists of a variety of tumours, which differ by their morphological features, molecular characteristics and outcome. Well-known prognostic factors, e.g. tumour grade and size, Ki-67, hormone receptor status, HER2 expression, lymph node status and patient age have been traditionally related to prognosis. Although the conventional prognostic markers are reliable in general, better markers to predict the outcome of an individual tumour are needed.

Matrix metalloproteinase-1 (MMP-1) expression has been reported to inversely correlate with survival in advanced cancers. In breast cancer MMP-1 is often upregulated, especially in basal-type breast tumours. The purpose of this retrospective study was to analyse MMP-1 expression in breast cancer cells and in cancer associated stromal cells and to correlate the results with traditional prognostic factors including p53 and bcl-2, as well as to patient survival in breast cancer subtypes.

Methods

Immunohistochemical analysis of MMP-1, ER, PR, Ki-67, HER2, bcl-2, p53 and CK5/6 expression was performed on 125 breast cancers. Statistical analyses were carried out using Kruskal-Wallis and Mann-Whitney -tests. In pairwise comparison Bonferroni-adjustment was applied. Correlations were calculated using Spearman rank-order correlation coefficients. Kaplan-Meier survival analyses were carried out to compare breast cancer-specific survival curves. Factors significantly associated with disease-specific survival in univariate models were included in multivariate stepwise.

Results

Positive correlations were found between tumour grade and MMP-1 expression in tumour cells and in stromal cells. P53 positivity significantly correlated with MMP-1 expression in tumour cells, whereas HER2 expression correlated with MMP-1 both in tumour cells and stromal cells. MMP-1 expression in stromal cells showed a significant association with luminal A and luminal B, HER2 overexpressing and triple-negative breast cancer subtypes.

Conclusions

The most important finding of this study was the independent prognostic value of MMP-1 as well as Ki-67 and bcl-2 expression in tumour cells. Our study showed also that both tumoural and stromal MMP-1 expression is associated with breast tumour progression and poor prognosis. A significant difference of MMP-1 expression by cancer associated stromal cells in luminal A, luminal B and triple-negative breast cancer classes was also demonstrated.

Please see related commentary article http://www.biomedcentral.com/1741-7015/9/95

What does matrix metalloproteinase-1 expression in patients with breast cancer really tell us?

Molecular and biochemical expressions of matrix metalloproteinases in breast cancer tissue and cells offers promise in helping us understand the breast cancer microenvironment, and also in the future it is hoped this will improve its detection, treatment and prognosis. In a retrospective study recently published in BMC Cancer, microenvironment predisposing to breast cancer progression, metastatic behavior and the expression of matrix metalloproteinase-1 (MMP-1) and its correlation with well-known biochemical, molecular and clinicopathologic factors in breast cancer cells and cancer-associated stromal cells was examined; this study also analyzed patient survival in different breast cancer subtypes. The positive correlation in breast tumor and stromal cells between MMP-1 expression and several markers of tumor grade and stage provide us with some useful new insights into important questions about the molecular profiling of the stromal microenvironment in metastatic breast cancer. The study showed that MMP-1 expression is strongly associated with poor clinical outcome, so now we look forward to future larger studies in breast cancer patients in which we can relate wider MMP molecular profiling to identify lethal tumor and stromal microenvironments predisposing to breast cancer progression, metastatic behavior and poor prognosis. Please see related article http://www.biomedcentral.com/1471-2407/11/348.

Current evidence on the relationship between four polymorphisms in the matrix metalloproteinases (MMP) gene and breast cancer risk: a meta-analysis

The matrix metalloproteinases (MMP) can degrade various components of the extracellular matrix and its functional genetic polymorphisms may be associated with breast cancer risk. However, this relationship remains controversial. A meta-analysis was conducted in order to investigate the potential association between four polymorphisms in the MMP gene and breast cancer risk. A database search yielded a total of 9 studies involving 2,597 cases and 2,618 controls. Four polymorphisms were included in the meta-analysis: MMP-1 -1607 2G/1G (rs1799750), MMP-2 -1306 C/T (rs243865), MMP-3 -1171 6A/5A (rs3025058) and MMP-9 -1562 C/T (rs3918242). Crude odds ratios (OR) with 95% confidence intervals (CI) were used to assess the strength of association. When all the studies were pooled into the meta-analysis, we found that breast cancer cases had a significantly higher frequency of CC genotype (OR = 1.27, 95% CI = 1.10, 1.47; P = 0.001) and lower frequency of CT genotype (OR = 0.78, 95% CI = 0.67, 0.91; P = 0.001) of MMP-2. No significant difference was found in any genotype of MMP-1, MMP-3 or MMP-9. In conclusion, this meta-analysis suggested that MMP-2 -1306 C/T polymorphism may contribute to breast cancer susceptibility. More studies were needed especially in Asians in the future.

Anesthetic technique and the cytokine and matrix metalloproteinase response to primary breast cancer surgery

BACKGROUND

Breast cancer is the most common malignancy in women. Surgery remains the most effective treatment. Several perioperative factors, including the surgical stress response, many anesthetics and opioids, adversely affect immune function. Regional anesthesia-analgesia attenuates perioperative immunosuppression. We tested the hypothesis that patients who receive combined propofol/paravertebral anesthesia-analgesia (propofol/paravertebral) exhibited reduced levels of protumorigenic cytokines and matrix metalloproteinases (MMPs) and elevated levels of antitumorigenic cytokines compared with patients receiving sevoflurane anesthesia with opioid analgesia (sevoflurane/opioid).

METHODS

Primary breast cancer surgery patients were randomized to propofol/paravertebral (n = 15) or sevoflurane/opioid (n = 17) and preoperative and postoperative serum concentrations of 11 cytokines (interleukin 1β [IL-1β], IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon γ, and tumor necrosis factor α) and 3 MMPs (MMP-1, MMP-3, and MMP-9) were measured.

RESULTS

Treatment groups were well balanced for age, weight, surgical procedure, and cancer pathologic diagnosis. Pain scores were lower at 1 and 2 hrs with paravertebral analgesia compared with morphine but similar at 24 hrs. Patients in the propofol/paravertebral group showed a greater percentage decrease in postoperative compared with preoperative IL-1β (median [quartiles], -26% [-15% to -52%] versus -4% [-14% to 2%], P = 0.003), a significant attenuation in elevated MMP-3 (2% [-39% to 12%] versus 29% [23%-59%], P = 0.011) and MMP-9 (26% [13%-54%] versus 74% [50%-108%], P = 0.02), and a significant increase in IL-10 (10% [5%-33%] versus -15% [20% to -2%], P = 0.001) compared with sevoflurane/opioid group. No significantly different changes in IL-2, IL-4, IL-5, IL-6, IL-8, IL-12p70, IL-13, interferon γ, tumor necrosis factor α, or MMP-1 were observed between the 2 groups.

CONCLUSIONS

Propofol/paravertebral anesthesia-analgesia for breast cancer surgery alters a minority of cytokines influential in regulating perioperative cancer immunity. Further evaluation is required to determine the significance of these observations.

Interleukin-6 and the IL-6 (-174) C/G polymorphism in breast pathologies and in HIV-infected patients

INTRODUCTION

Breast cancer and acquired immunodeficiency syndrome (AIDS) are key issues for modern medicine. The aim of the current study was to present how cytokines, in the example of IL-6 and its polymorphism, can affect these two conditions.

MATERIAL AND METHODS

Thirty-one women with benign breast tumours, 42 breast cancer patients and 40 HIV-infected females were enrolled in the study. Serum IL-6 levels were determined by ELISA. The IL-6 polymorphism was genotyped by PCR-RFLP.

RESULTS

Serum IL-6 in patients with benign breast tumours was significantly lower than in females with breast cancer (p = 0.017) and HIV-infected women (p = 0.032). We did not find statistically significant differences in serum IL-6 level between females with breast cancer and HIV-infected women (p = 0.749). Comparing the distribution of genotypes and frequency of the IL-6 (-174) C/G polymorphism between the three study groups - breast cancer patients, patients with benign breast tumours, and HIV-infected patients - we did not find any statistically significant differences.

CONCLUSIONS

IL-6 can play an important role in pathogenesis of breast cancer and HIV infection and its level is higher than in the control group irrespective of distribution of genotypes and frequency of the IL-6 (-174) C/G polymorphism.

Cholesterol, a Major Component of Caveolae, Down-regulates Matrix Metalloproteinase-1 Expression through ERK/JNK Pathway in Cultured Human Dermal Fibroblasts

BACKGROUND

Cholesterol is a major component of specialized membrane microdomains known as lipid rafts or caveolae, which modulate the fluidity of biological membranes. Membrane cholesterol therefore plays an important role in cell signaling and vesicular transport.

OBJECTIVE

In this study, we investigated the effects of cholesterol on matrix metalloproteinase-1 (MMP-1) expression in human dermal fibroblasts.

METHODS

MMP-1 mRNA and protein expression were determined by RT-PCR and Western blotting, respectively. AP-1 DNA binding activity was detected by electrophoretic mobility shift assays. The amount of cholesterol was analyzed by cholesterol assay kit.

RESULTS

We observed that MMP-1 mRNA and protein expression was dose-dependently decreased by cholesterol treatment. In contrast, cholesterol depletion by a cholesterol depletion agent, methyl-beta-cyclodextrin (MβCD) in human dermal fibroblasts, increased MMP-1 mRNA and protein expression in a dose-dependent manner. Also, we investigated the regulatory mechanism of MβCD-induced MMP-1 expression: cholesterol depletion by MβCD, activated ERK1/2 and JNK, but not p38 MAPK cascade, and it also significantly increased c-Jun phosphorylation, c-Fos expression and activator protein-1 binding activity. Furthermore, the inhibition of ERK or JNK with specific chemical inhibitors prevented MβCD-induced MMP-1 expression, which indicates that ERK and JNK play an important role in cholesterol depletion-mediated MMP-1 induction. In addition, MβCD-induced phosphorylation of ERK and JNK and MMP-1 expression were suppressed by cholesterol repletion.

CONCLUSION

Our results suggest that cholesterol regulates MMP-1 expression through the control of ERK and JNK activity in human dermal fibroblasts.

Functional polymorphism of the MMP-1 promoter (-1607 1G/2G) in potentially malignant and malignant head and neck lesions in an Indian population

Matrix metalloproteinases (MMP) are a family of zinc-dependent proteases that degrade the entire component of the extracellular matrix. Our study explores the association of the MMP1 gene promoter (-1607 1G/2G) polymorphisms in oral submucous fibrosis (OSMF) and head and neck squamous cell carcinoma (HNSCC) in an Indian population. The MMP1 single-nucleotide polymorphism (SNP) was genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in 412 patients with OSMF, 422 with HNSCC and 426 controls. Our results showed that the frequency of 1G/2G or 2G/2G promoter genotypes having the 2G allele is associated with higher enzymatic activity and significantly increases in OSMF (p<0.001) and HNSCC cases (p<0.00). In this study, results concluded that SNPs in the MMP1 promoter region may be associated with susceptibility to OSMF as well as HNSCC in an Indian population and addiction habits such as areca nut chewing and alcohol abuse may enhance the expression of the 2G allele of MMP1 genes in OSMF and HNSCC cases.

MMP9 polymorphisms and breast cancer risk: a report from the Shanghai Breast Cancer Genetics Study

In addition to tumor invasion and angiogenesis, matrix metalloproteinase (MMP)9 also contributes to carcinogenesis and tumor growth. Genetic variation that may influence MMP9 expression was evaluated among participants of the Shanghai Breast Cancer Genetics Study (SBCGS) for associations with breast cancer susceptibility. In stage 1, 11 MMP9 single nucleotide polymorphisms (SNPs) were genotyped by the Affymetrix Targeted Genotyping System and/or the Affymetrix Genome-Wide Human SNP Array 6.0 among 4,227 SBCGS participants. One SNP was further genotyped using the Sequenom iPLEX MassARRAY platform among an additional 6,270 SBCGS participants. Associations with breast cancer risk were evaluated by odds ratios (OR) and 95% confidence intervals (CI) from logistic regression models that included adjustment for age, education, and genotyping stage when appropriate. In Stage 1, rare allele homozygotes for a promoter SNP (rs3918241) or a non-synonymous SNP (rs2274756, R668Q) tended to occur more frequently among breast cancer cases (P value = 0.116 and 0.056, respectively). Given their high linkage disequilibrium (D' = 1.0, r (2) = 0.97), one (rs3918241) was selected for additional analysis. An association with breast cancer risk was not supported by additional Stage 2 genotyping. In combined analysis, no elevated risk of breast cancer among homozygotes was found (OR: 1.2, 95% CI: 0.8-1.8). Common genetic variation in MMP9 was not found to be significantly associated with breast cancer susceptibility among participants of the Shanghai Breast Cancer Genetics Study.

Promoter polymorphisms in matrix metallopeptidase 1 and risk of cutaneous melanoma

Matrix metallopeptidase 1 (MMP1) is one of the interstitial collagens in the extracellular matrix metalloproteinase family and involved in tumour behaviours. However, there is no report on the role of genetic variation in MMP1 in risk of cutaneous melanoma (CM). We investigated the association between genotypes and haplotypes of seven reported MMP1 promoter polymorphisms [-1607G ins/del (2G/1G), -839G>A, -755T>G, -519A>G, -422A>T, -340A>G and -320T>C, genotyped by the TaqMan assay] and CM risk in 872 patients and 873 cancer-free controls. These seven polymorphisms were not in linkage disequilibrium among each other (r(2)<0.63). Compared to their common homozygous genotypes, the variant -519GG was associated with significantly decreased CM risk [adjusted odds ratio (OR)=0.71, 95% confidence interval (CI)=0.52-0.99], whereas variants -422TT and -320CC were associated with significantly increased CM risk (OR=1.50, 95% CI=1.11-2.03 and OR=1.72, 95% CI=1.05-2.81, respectively) after adjustment for age, sex, family history and sun-exposure-related risk factors. The number of risk alleles of these three polymorphisms was associated with CM risk in a dose-response manner (P(trend)=0.0002). In the stratification analysis, we found that the associations of these polymorphisms with CM risk were modified by some of the risk factors. Furthermore, the haplotypes Gdel-A-G-A-T-G-T and G-G-G-A-T-A-T were associated with significantly increased CM risk (ORs=1.56 and 2.13, 95% CIs=1.02-2.38 and 1.22-3.70, respectively). These findings suggest that MMP1 promoter polymorphisms may individually or jointly play roles in the development of CM.

Matrix metalloproteinase-9 promoter gene polymorphism (-1562C>T) in nasal polyposis

BACKGROUND

Expression of matrix metalloproteinase (MMP)-9 increases in nasal polyp tissues. However, the impact of MMP-9 genotypes on the development of nasal polyposis (NP) is unknown. The aim of this study was to examine a potential association of MMP-9 promoter gene polymorphism with the development of NP.

METHODS

A prospective and case-control study was performed on 93 patients with NP and 115 controls without sinonasal disease. Genotypes of MMP-9 (-1562C>T) were identified by restriction fragment length polymorphism analyses after polymerase chain reaction.

RESULTS

The frequency of -1562CT genotype of MMP-9 was significantly high in NP patients with aspirin-induced asthma (p = 0.014). Distribution of T allele was significantly high in NP patients with aspirin-induced asthma (p = 0.013). MMP-9 genotypes were not associated with gender or the presence of atopy.

CONCLUSION

In this study, MMP-9 -1562CT genotype was associated with susceptibility to NP in aspirin-induced asthmatic patients. Because this report is a population-based study, further research should be performed on larger study subjects to reveal the precise role of MMP-9 promoter gene polymorphism in the development of NP.

Liver expression of matrix metalloproteases and their inhibitors in hepatocellular carcinoma

BACKGROUND

Several studies have suggested the significance of some metalloproteases in the malignant behaviour of hepatocellular carcinoma.

AIMS

To evaluate the liver expression of MMPs and their tissular inhibitors in patients with HCC.

METHODS

An immunohistochemical study using tissue microarrays on samples obtained from 30 HCC patients, with antibodies against MMPs (1, 2, 7, 9, 11, 13 and 14) and TIMPs (1, 2 and 3) was performed. Results were correlated with various clinico-pathological findings and with overall survival.

RESULTS

MMP-1 is mainly expressed by stromal cells, and MMP-13, TIMP-1 and TIMP-2 by inflammatory cells. A positive correlation between MMP-1 expression and larger size tumours (p<0.01) was found. Increased TIMP-2 expression was associated with higher preoperative serum levels of alpha-fetoprotein (p<0.01). Unsupervised hierarchical clustering for total score values designated two groups, one of them characterised by high MMPs and TIMPs expressions, including 21 cases (70%) for tumour cell clustering, 5 cases for fibroblasts (16.6%) and 6 cases for inflammatory cells (20%). All patients showing elevated MMPs and TIMPs expression in stromal cells presented a poor prognosis (p<0.05).

CONCLUSIONS

High liver MMPs and TIMPs expressions in peritumour stromal cells are related to a poorer prognosis in HCC.

Matrix Metalloproteinase-9 (MMP9)-A Mediating Enzyme in Cardiovascular Disease, Cancer, and Neuropsychiatric Disorders

Matrix metalloproteinase-9 (MMP9) has been implicated in numerous somatic illnesses, including cardiovascular disorders and cancer. Recently, MMP9 has been shown to be increasingly important in several aspects of central nervous system activity. Furthermore, a pathogenic role for this enzyme has been suggested in such neuropsychiatric disorders as schizophrenia, bipolar illness, and multiple sclerosis. In this paper, the results of biochemical and molecular-genetic studies on MMP9 that have been performed in these pathological conditions will be summarized. Furthermore, I hypothesize that the MMP9 gene, as shown by functional −1562 C/T polymorphism studies, may be mediating the relationship of neuropsychiatric illnesses (schizophrenia, bipolar mood disorder, multiple sclerosis) that are comorbid with cardiovascular disease and cancer.

Polymorphisms of matrix metalloproteinases 1, 2, 3 and 9 and susceptibility to lung, breast and colorectal cancer in over 30,000 subjects

A variety of susceptibility genes have been associated with cancer but definitive conclusions have been difficult to draw partly hampered by the small number of subjects in each study. We undertook a comprehensive genetic meta-analysis of all matrix metalloproteinase (MMP) genes investigated using an allelic-association case-control model in the 3 major cancers of lung, breast and colorectal cancer. Electronic databases were searched until and including July 2008 for any MMP genetic association study in lung, breast and colorectal cancer. Odds ratio (OR) and 95% confidence intervals (CI) were determined for each gene disease association using fixed and random effect models. Twenty-five studies addressing 5 polymorphisms in 4 genes were analyzed among 30,651 individuals (15,328 cases and 15,253 controls). The MMP-1 nt-1607 polymorphism was significantly associated with colorectal cancer in both the dominant (OR, 1.66; 95% CI, 1.14-2.42; p = 0.008) and recessive (OR, 1.59; 95% CI, 1.15-2.20; p = 0.005) models. MMP-2(1306C-->T) (OR, 0.53; 95% CI, 0.40-0.72; p < 0.0001) and 735(C-->T) (OR, 0.65; 95% CI, 0.53-0.79; p < 0.0001) were significantly associated with protection against lung cancer. No association was found with the MMP 1, 2, 3 or 9 polymorphisms with breast cancer, MMP-1, 3 or 9 with lung cancer or MMP-2, 3 or 9 with colorectal cancer. There may be a genetic influence in the development of colorectal and lung cancer. Subjects with the MMP-1 nt-1607 polymorphism have an increased association with colorectal cancer. Those homozygous for either the MMP-2/1306T or 735T allele may be at reduced risk of lung cancer, although the evidence base is small.

Expression of matrix metalloproteinases (MMPs) in primary human breast cancer and breast cancer cell lines: New findings and review of the literature

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of structural and functional related endopeptidases. They play a crucial role in tumor invasion and building of metastatic formations because of their ability to degrade extracellular matrix proteins. Under physiological conditions their activity is precisely regulated in order to prevent tissue disruption. This physiological balance seems to be disrupted in cancer making tumor cells capable of invading the tissue. In breast cancer different expression levels of several MMPs have been found.

METHODS

To fill the gap in our knowledge about MMP expression in breast cancer, we analyzed the expression of all known human MMPs in a panel of twenty-five tissue samples (five normal breast tissues, ten grade 2 (G2) and ten grade 3 (G3) breast cancer tissues). As we found different expression levels for several MMPs in normal breast and breast cancer tissue as well as depending on tumor grade, we additionally analyzed the expression of MMPs in four breast cancer cell lines (MCF-7, MDA-MB-468, BT 20, ZR 75/1) commonly used in research. The results could thus be used as model for further studies on human breast cancer. Expression analysis was performed on mRNA and protein level using semiquantitative RT-PCR, Western blot, immunohistochemistry and immunocytochemistry.

RESULTS

In summary, we identified several MMPs (MMP-1, -2, -8, -9, -10, -11, -12, -13, -15, -19, -23, -24, -27 and -28) with a stronger expression in breast cancer tissue compared to normal breast tissue. Of those, expression of MMP-8, -10, -12 and -27 is related to tumor grade since it is higher in analyzed G3 compared to G2 tissue samples. In contrast, MMP-7 and MMP-27 mRNA showed a weaker expression in tumor samples compared to healthy tissue. In addition, we demonstrated that the four breast cancer cell lines examined, are constitutively expressing a wide variety of MMPs. Of those, MDA-MB-468 showed the strongest mRNA and protein expression for most of the MMPs analyzed.

CONCLUSION

MMP-1, -2, -8, -9, -10, -11, -12, -13, -15, -19, -23, -24, -27 and -28 might thus be associated with breast cancer development and tumor progression. Therefore, these MMPs are proper candidates for further functional analysis of their role in breast cancer.

Putative functional polymorphisms of MMP9 predict survival of NSCLC in a Chinese population

Matrix metalloproteinases (MMPs) play a crucial role in cancer progression and their over-expression is often associated with unfavorable survival of non-small cell lung cancer (NSCLC). Because genetic variants can alter expression level or biological activity of MMPs, we hypothesized that potentially functional single nucleotide polymorphisms (SNPs) in key MMP genes may be associated with the survival of NSCLC patients. We selected and genotyped 14 putative functional SNPs in six MMP genes (MMP1, MMP2, MMP3, MMP7, MMP9 and MMP12) using PCR-RFLP methods in 561 NSCLC patients. Kaplan-Meier method with the log-rank test and Cox proportional hazard models were used for the survival analyses. The C-1562T, Arg279Gln and Arg668Gln polymorphisms in MMP9 were significantly associated with survival of patients with NSCLC (log-rank p values = 0.032, 0.038 and 0.036, respectively). The C-1562T and Arg668Gln loci were in complete linkage disequilibrium (r(2) = 1). Patients carrying the 668Gln allele had improved survival with a median survival time (MST) of 51.6 months, compared with 21.8 months for those with the 668Arg/Arg genotype (log-rank p = 0.010). In contrast, the 279Gln/Gln genotype was associated with a significantly shortened MST (17.3 months, log-rank p = 0.030) in the recessive model. In the final multivariate Cox regression model, 279Gln/Gln was identified as an independent prognostic factor with an adjusted hazard ratio of 1.60 (95% confidence interval 1.07-2.41). The MMP9 Arg279Gln and Arg668Gln SNPs are potential predictors of survival in NSCLC patients.

Associations of matrix metalloproteinase-9 protein polymorphisms with lymph node metastasis but not invasion of gastric cancer

PURPOSE

Like most cancers, gastric cancer has a complex multistep etiology that involves both environmental and genetic factors. Matrix metalloproteinase-9 (MMP-9) is frequently overexpressed in gastric cancer. We investigated the effect of the genetic differences in MMP-9 coding region on the occurrence and progression of gastric cancer.

EXPERIMENTAL DESIGN

A case-control study was conducted in a population of 74 patients and 100 healthy people in southeast China. Individuals were genotyped for two single nucleotide polymorphisms (SNP) in MMP-9: R279Q and P574R. Genotypic distributions between patient and control groups were compared for correlations with cancer occurrence. Associations between genotypic distributions and several clinicopathologic features were also analyzed using univariate tests, multivariate logistic regression modeling, and stratified analyses.

RESULTS

Significant associations were revealed between both SNPs and lymph node metastasis [P = 0.012 and 0.025; odds ratio (OR), 3.4 and 2.8, respectively]. After adjustment using logistic regression for the potential confounding effects of gender, age, and location of the tumors, homozygous MMP-9 279RR and 574PP are more evidently associated with lymph node metastasis with OR(adjusted) of 5.7 [95% confidence interval (95% CI), 1.80-18.34] and 4.2 (95% CI, 1.37-12.69). The homozygous 279R-574P haplotype showed a stronger association by an OR(adjusted) of 6.1 (95% CI, 1.92-12.29) and was also associated with the 1-year postoperative mortality (OR(adjusted), 6.5; 95% CI, 1.18-35.74). Interestingly, our data also suggested that the MMP-9 polymorphisms seem to result in higher risk of lymph node metastasis through a pathway independent of cancer invasion because no positive associations were found between these polymorphisms and cancer invasion (OR, 0.59 < 1). The stratified analyses indicated a synergistic interaction between the MMP-9 polymorphisms and the type of diffuse in affecting lymph node metastasis (OR, 13.4; P(between strata) = 0.04). Significant association between both SNPs and the overall occurrence of gastric cancer was not observed.

CONCLUSION

The present study has shown significant associations between the two nonsynonymous MMP-9 polymorphisms with lymph node metastasis in gastric cancer, especially with the diffuse type. The relatively large values of ORs and disassociation with cancer invasion suggest that the genetic differences of MMP-9 protein play an important and specific role in lymph node metastases, and therefore, further investigation of the underlying molecular mechanism is warranted.

Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion

BACKGROUND

Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion.

METHODS

Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided.

RESULTS

Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04).

CONCLUSION

This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.

Matrine inhibits PMA-induced MMP-1 expression in human dermal fibroblasts

Matrix metalloproteinase-1 (MMP-1) plays an important role in the maintenance and turnover of extracellular matrix (ECM) macromolecules. Remodelling of extracellular matrix by MMPs is a hallmark feature of physiological and pathological processes. In this study, in order to establish the therapeutic potential of matrine, we investigated its effect on MMP-1 expression in human dermal fibroblast cells. We found that matrine inhibited both MMP-1 mRNA and protein expression induced by PMA (phorbol myristate acetate). Therefore, we characterized the inhibitory mechanism of matrine on PMA-induced MMP-1 expression. Matrine inhibited PMA-induced activation of the AP-1 promoter, an important nuclear transcription factor in MMP-1 expression. Additionally, we detected that matrine suppressed the PMA-induced phosphorylation of two mitogen-activated protein kinases, extracellular signal-regulated protein kinase and c-Jun N-terminal kinase, but did not suppress the PMA-induced phosphorylation of p38 kinase. These results suggest that matrine suppresses PMA-induced MMP-1 expression through inhibition of the AP-1 signaling pathway and also may be beneficial for treatment of some inflammatory skin disorders.

Genetic polymorphisms of matrix metalloproteinases in lung, breast and colorectal cancer

The matrix metalloproteinases (MMPs) can degrade various components of the extracellular matrix and are implicated in the development and progression of cancer. There is evidence suggesting an association of MMP gene polymorphisms with cancer susceptibility and/or metastasis. This paper reviews the findings on several single nucleotide polymorphisms in the collagenase, stromelysin and gelatinase genes in lung cancer, breast cancer and colorectal cancer.

Haplotypes in matrix metalloproteinase gene cluster on chromosome 11q22 contribute to the risk of lung cancer development and progression

PURPOSE

Matrix metalloproteinases (MMP) play important roles in cancer development and single nucleotide polymorphisms (SNP) in some MMP genes were shown to confer susceptibility to certain cancers. This study examined the association between genotypes and haplotypes in the MMP1-MMP3-MMP12 gene cluster and risk of lung cancer development and metastasis.

EXPERIMENTAL DESIGN

A two-stage investigation was conducted. First, 35 SNPs covering these genes were selected and validated in 190 patients and 190 controls. Twenty-two validated SNPs were then analyzed in an entire case-control panel consisting of 711 patients and 716 controls. Associations with the risk of lung cancer were estimated by logistic regression.

RESULTS

The investigated MMP gene region could be partitioned into two major haplotype blocks. One common haplotype in the block composed of major part of MMP1 transcription region was significantly associated with increased risk for the development [odds ratio (OR), 1.35; 95% confidence interval (95% CI), 1.11-1.63; P = 0.01; permutated P = 0.134] and distant metastasis of lung cancer (ORs for stage IV versus stages I-III, 1.67; 95% CI, 1.12-2.50; P = 0.009; permutated P = 0.048) and the other showed a protective effect against metastasis (ORs for stage IV versus stages I-III, 0.22; 95% CI, 0.07-0.62; P = 0.001; permutated P = 0.011). Another common haplotype in the block across MMP3 was significantly associated with decreased risk for developing lung cancer (OR, 0.71; 95% CI, 0.59-0.86; P = 0.003; permutated P = 0.027).

CONCLUSIONS

The observed multiple cancer-associated genetic variants suggested that the MMP1-MMP3-MMP12 gene cluster plays important roles in lung cancer development and progression.

Study of matrix metalloproteinases and their inhibitors in breast cancer

An immunohistochemical study was performed using tissue microarrays and specific antibodies against matrix metalloproteinases (MMPs) 1, 2, 7, 9, 11, 13, 14, and their tisullar inhibitors (TIMPs) 1, 2, and 3. More than 2600 determinations on cancer specimens from 131 patients with primary ductal invasive tumours of the breast (65 with and 66 without distant metastasis) and controls were performed. Staining results were categorised using a score based on the intensity of the staining and a specific software program calculated the percentage of immunostained cells automatically. We observed a broad variation of the total immunostaining scores and the cell type expressing each protein. There were multiple and significant associations between the expression of the different MMPs and TIMPs evaluated and some parameters indicative of tumour aggressiveness, such as large tumour size, advanced tumour grade, high Nottinham prognostic index, negative oestrogen receptor status, peritumoural inflammation, desmoplastic reaction, and infiltrating tumoural edge. Likewise, the detection of elevated immunohistochemical scores for MMP-9, 11, TIMP-1, and TIMP-2, was significantly associated with a higher rate of distant metastases. The expression of MMP-9 or TIMP-2 by tumour cells, MMP-1, 7, 9, 11, 13, or TIMP-3 by fibroblastic cells, and MMP-7, 9, 11, 13, 14, TIMP-1, or TIMP-2 by mononuclear inflammatory cells, was also significantly associated with a higher rate of distant metastases.

From DNA to RNA to disease and back: the 'central dogma' of regulatory disease variation

Much of the focus of human disease genetics is directed towards identifying nucleotide variants that contribute to disease phenotypes. This is a complex problem, often involving contributions from multiple loci and their interactions, as well as effects due to environmental factors. Although some diseases with a genetic basis are caused by nucleotide changes that alter an amino acid sequence, in other cases, disease risk is associated with altered gene regulation. This paper focuses on how studies of gene expression variation might complement disease studies and provide crucial links between genotype and phenotype.

Therapeutic intervention of experimental breast cancer bone metastasis by indole-3-carbinol in SCID-human mouse model

Several lines of experimental evidence have suggested that chemokine receptor CXCR4, a metastasis-promoting molecule, may play important roles in breast cancer bone metastasis. There is emerging evidence linking CXCR4 to matrix metalloproteinases (MMP) as well as their regulator nuclear factor-kappaB (NF-kappaB), a key transcription factor, which is known to activate metastasis-promoting molecules for many types of malignancies, including breast cancer. A recent study also showed that promoter region of CXCR4 has several NF-kappaB-binding sites, suggesting that there may be a cross-talk between CXCR4 and NF-kappaB. We have shown previously that indole-3-carbinol (I3C), a natural compound present in vegetables of the genus Brassica, can inhibit NF-kappaB in breast cancer cells. However, there are no reports in the literature showing any effect of I3C on CXCR4 expression in vitro and in vivo. We therefore examined whether I3C could inhibit bone metastasis of breast cancer by inhibiting CXCR4 and MMP-9 expression mediated via the inhibition of the NF-kappaB signaling pathway. Here, we have modified the severe combined immunodeficient (SCID)-human mouse model of experimental bone metastasis for use with the MDA-MB-231 breast cancer cell line. In this animal model, we found that I3C significantly inhibited MDA-MB-231 bone tumor growth, and our results were correlated with the down-regulation of NF-kappaB. Moreover, we found that I3C significantly inhibited the expression of multiple genes involved in the control of metastasis and invasion in vitro and in vivo, especially the expression of CXCR4 and MMP-9 along with pro-MMP-9, with concomitant decrease in Bcl-2 and increase in the proapoptotic protein Bax. From these results, we conclude that the CXCR4/NF-kappaB pathway is critical during I3C-induced inhibition of experimental breast cancer bone metastasis. These results also suggest that I3C could be a promising agent for the prevention and/or treatment of breast cancer bone metastasis in the future.

A preliminary in silico lead series of 2-phthalimidinoglutaric acid analogues designed as MMP-3 inhibitors

Matrix metalloproteinases (MMPs) have been the subject of intense research because of their roles in tumor metastasis and in the rise and spread of degenerative diseases such as osteo- and rheumatoid arthritis. A preliminary class of 140 druglike, small-molecule matrix metalloproteinase-3 inhibitors, intended as starting scaffolds for optimization and synthesis, has been designed in silico using a series of highly predictive three-dimensional quantitative structure-activity relationship models, including comparative molecular field analysis and comparative molecular similarity indices analysis, with docking and scoring. Thalidomide was chosen as the skeleton on which to base the new lead series, as it moderately inhibits MMP-3, is antiangiogenic, and lends itself easily to structural modifications. Most of the new compounds demonstrate medium to high predicted biological activity and good bioavailability as estimated by the octanol-water partition coefficient ClogP. Compound 102 in particular exhibits extremely favorable predicted activity against MMP-3; is moderately bioavailable; satisfies Lipinski's Rule of Five; and shows promise for further optimization, synthesis, and experimental evaluation as a potential adjunct anticancer or antirheumatic therapeutic.

Promoter polymorphisms in matrix metalloproteinases and their inhibitors: few associations with breast cancer susceptibility and progression

The importance of matrix metalloproteinases and their inhibitors in tumor progression is well documented. We wanted to investigate if single nucleotide polymorphisms (SNPs) in the promoter regions of these genes are associated with susceptibility to or progression of breast cancer. In this, so far largest case-control study, we genotyped eight SNPs in the MMP1, MMP2, MMP3, MMP9, MMP13, RECK and TIMP3 genes in a well-characterized breast cancer series of 959 cases and 952 controls from Sweden. Even though we did not correct for multiple comparisons, only a few associations were noted. We observed a moderately increased risk for the TT homozygotes of the MMP9-1562 C/T SNP (OR 1.88, 95% CI 0.97-3.63) and for the C allele carriers of the TIMP3-1296 T/C SNP (OR 1.25, 95% CI 1.05-1.50). In the survival analysis, only the TC heterozygotes of the RECK-420 T/C SNP showed a better survival compared to the TT homozygotes (P = 0.02 in all cases and P = 0.03 in lymph node negative cases). None of the other SNPs conferred an increased breast cancer risk, nor did they correlate with survival. A combination of the -585 TT homozygosity in the RECK gene and the -1296 TT homozygosity in the TIMP3 gene correlated with estrogen and progesterone receptor status (OR 1.81, 95% CI 1.03-3.21 and OR 2.10, 95% CI 1.18-3.86, respectively), and a combination of the -1306 TT homozygosity in the MMP2 gene and the -1562 CC homozygosity in the MMP9 gene with progesterone receptor status (OR 2.34, 95% CI 1.08-5.08). Although our study suggests some correlations between the studied SNPs and the progression of breast cancer, the rarity of the risk genotypes limits their usefulness in the clinic.

Matrix Metalloproteinase Polymorphisms and Survival in Stage I Non–Small Cell Lung Cancer

PURPOSE

The matrix metalloproteinases (MMP) are a family of enzymes that can degrade extracellular matrix and facilitate invasion through the basement membrane. Several polymorphisms in MMP-1, MMP-2, MMP-3, and MMP-12 have been described, some of which lead to differential transcription. We hypothesized that polymorphisms in these MMP genes may be associated with survival outcomes in early-stage non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

We evaluated the relationship between MMP-1, MMP-2, MMP-3, and MMP-12 polymorphisms and both recurrence-free survival (RFS) and overall survival (OS) among 382 patients with stage I NSCLC. Analyses of genotype associations with survival outcomes were done using Cox proportional hazards models and Kaplan-Meier methods and the log-rank test.

RESULTS

Patients carrying the variant G allele of the MMP-12 1082A/G polymorphism had significantly worse outcomes [crude hazard ratio (HR) for OS 1.74; 95% confidence interval (95% CI), 1.18-2.58, P=0.006; crude HR for RFS, 1.53; 95% CI, 1.05-2.23, P=0.03]. After adjusting for age, sex, stage, pack-years of smoking, and histologic subtype, the MMP-12 1082A/G polymorphism remained significantly associated with survival outcomes [adjusted HR (AHR) for OS, 1.94; 95% CI, 1.28-2.97, P=0.002; AHR for RFS, 1.61; 95% CI, 1.07-2.41, P=0.02]. None of the other MMP polymorphisms was significantly associated with survival.

CONCLUSIONS

Our results show that patients with stage I NSCLC carrying the variant G allele of the MMP-12 1082A/G polymorphism have worse survival.

HRPAP20: a novel calmodulin-binding protein that increases breast cancer cell invasion

We previously reported the identification of HRPAP20 (hormone-regulated proliferation-associated protein 20), a novel hormone-regulated, proliferation-associated protein. In tumor cell lines, constitutive HRPAP20 expression enhanced proliferation and suppressed apoptosis, characteristics frequently associated with malignant progression. Here, we report that highly invasive breast cancer cell lines and human breast tumor specimens express elevated HRPAP20, which in transfection experiments in MCF-7 and MDA-MB-231 cells, increased invasion. Results from mechanistic studies revealed that HRPAP20 bound to calmodulin (CaM) via a conserved CaM-binding motif. Transfection of MCF-7 breast cancer cells with HRPAP20 harboring a mutated CaM-binding motif (HRPAP20K73A) inhibited its interaction with CaM and failed to increase invasion. Other experiments revealed that transfection with HRPAP20, but not HRPAP20K73A, increased secretion of matrix metalloproteinase-9 (MMP-9). Moreover, knockdown of HRPAP20 with small interfering RNA in MCF-7/HRPAP20 transfectants and wild-type MDA-MB-231 cells reduced invasion and inhibited secretion of MMP-9. Together these observations suggest that HRPAP20 may be an important regulator of breast tumor cell invasion by a CaM-mediated mechanism that leads to increased MMP-9 secretion. We conclude that dysregulation of HRPAP20 expression in tumor cells may contribute to the observed phenotypic changes associated with breast cancer progression.

Differential expression of matrix metalloproteinases in brain- and bone-seeking clones of metastatic MDA-MB-231 breast cancer cells

Matrix Metalloproteinases (MMPs) play a crucial role in breast cancer metastasis. We examined the mRNA and protein expression of several MMPs in brain- and bone-seeking clones of MDA-MB-231 breast cancer cells, their transcriptional regulation and their functional role in the metastatic process. MMP mRNA expression was examined using real-time reverse transcription polymerase chain reaction. Protein expression was examined using enzyme linked immunosorbent essay (ELISA). The inducibility of mRNA and protein expression was tested with TPA (phorbol 12-myristate 13-acetate; 50 microM); epidermal growth factor and transforming growth factor beta (20 ng/ml both). Migration and invasion assays were performed with the QCM 96-Well Migration/Invasion Assay (8 microm; Chemicon) over 24 h with or without specific MMPs inhibitors (MMP Inhibitor I Mix (5 microM); MMP-2/MMP-9 Inhibitor III (50 microM); EMD Biosciences). We found significantly higher mRNA expression of MMP-1 and -9 in brain-seeking 231-clones in comparison to -bone and -parental cells. In contrast, the mRNA expression of MMP-3 and -14 was comparable in all cells lines examined and MMP-13 expression was lower in both selective metastatic lines. MMP-2 and -8 were not expressed. ELISA revealed a higher amount of total as well as active MMP-1 and -9 in brain-seeking cells. TPA stimulation showed that MMP-1 and -9 transcription was inducible on the mRNA and protein level in 231-parental but not in 231-brain or -bone. 231-brain showed the highest migration and invasive capacity which could be decreased by the application of MMP-1 and/or MMP-9 inhibitor. Our results indicate functional importance of MMP-1 and -9 overexpression in brain metastasis in an in vitro model.