| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Epidemiology and Prevention |
Department of Etiology and Carcinogenesis, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021
| ABSTRACT |
|---|
|
|
|---|
| INTRODUCTION |
|---|
|
|
|---|
In contrast to the majority of MMPs, MMP-2 is constitutively expressed by a large number of cell types and overexpressed in a wide variety of human cancer, including gastroesophageal cancer (5, 6, 7, 8)
. Although the activity of MMP-2 is known to be regulated by post-transcriptional mechanisms, including the activation of proenzyme and inhibition of enzyme activity (1
, 4)
, transcriptional regulation is also believed to be pivotally important because the human MMP2 promoter contains a number of cis-acting regulatory elements, and several transcription factors, including p53, Sp1, Sp3, and AP-2, participate in the control of its constitutive expression (9
, 10)
. Recently, Price et al. (11)
reported a single nucleotide polymorphism in the promoter of the MMP2 gene (-1306C/T). The -1306C
T transition is located in a core recognition sequence of Sp1 (CCACC box), which abolishes the Sp1-binding site and consequently diminishes promoter activity. Transient transfection experiments showed that reporter gene expression driven by the C allelic MMP2 promoter was significantly greater than reporter gene expression driven by the T allelic counterpart both in epithelial cells and macrophages, indicating the functional significance of this polymorphism (11)
.
The cancers in which an effect for MMP-2 has been established are characterized by varying individual susceptibility, implying the role of genetic factors. However, like many MMPs, MMP-2 is not up-regulated by gene amplification or activating mutations, and genetic alternations in the gene of the cancer cells are generally lacking. Therefore, germ-line polymorphisms that alter constitutive and/or induced expression and enzyme activity of MMP-2 may affect individual susceptibility to certain cancers. It has been hypothesized that the MMP2 -1306C alleles might render increased risk for carcinogenesis because of an elevated level of MMP-2 expression over a lifetime. We have recently shown in a molecular epidemiological study that the frequency of the MMP2 -1306CC genotype was significantly higher in patients with lung cancer than in the healthy population, and this genotype was associated with several folds of increased risk of lung cancer solely or in a manner of interaction with smoking exposure (12) . The present report described a case control study that aimed to test the hypothesis in GCA. In addition, we also assessed the contribution of the MMP2 polymorphism to risk of metastasis of the cancer.
| MATERIALS AND METHODS |
|---|
|
|
|---|
MMP-2 Genotyping.
Genomic DNA was isolated from peripheral blood of the controls and most of the cases. Approximately 30% of DNA samples from cases were isolated from surgically resected "normal" tissues adjacent to the tumor of GCA patients. MMP2 genotyping was accomplished by PCR-based DHPLC analysis and direct DNA sequencing as reported previously (12)
. The primers used to amplify a 295-bp fragment of MMP2 promoter containing 1306 C/T site were: MMP-2F, 5'-CTG ACC CCC AGT CCT ATC TGC C and MMP-2R, 5'-TGT TGG GAA CGC CTG ACT TCA G. PCR was accomplished with a 25-µl reaction mixture containing
100 ng of DNA, 1 µM each primer, 0.2 mM deoxynucleotide triphosphate, 2 mM MgCl2, 1 unit of Taq DNA polymerase with 1 x reaction buffer (Promega, Madison, WI), and 2% DMSO. The PCR profile consisted of an initial melting step of 2 min at 94°C, followed by 35 cycles of 30 s at 94°C, 30 s at 64°C, and 45 s at 72°C, and a final elongation of 7 min at 72°C. DHPLC analysis was performed on a Transgenomic WAVE System (Transgenomic, Inc., Omaha, NE). The detailed genotyping process was described in our recent publication (12)
. Briefly, each PCR product was denatured for 1 min at 94°C and then gradually reannealed by decreasing sample temperature from 94°C to 45°C over a period of 30 min to form homo- and/or hetero-duplexes. The PCR products were then applied to the DHPLC column and eluted with a linear acetonitrile gradient at a flow rate of 0.9 ml/min. The genotypes of MMP2 1306 C/T revealed by DHPLC analysis were further confirmed by DNA sequencing. To ensure quality control, genotyping was performed with blinding to case control status, and a 10% random sample of cases and controls was genotyped twice by different persons; the reproducibility was 100%.
Statistical Analysis.
Pearsons
2 test was used to examine differences in demographic variables, smoking, and distributions of genotypes between cases and controls and metastatic and nonmetastatic cases. The associations between the MMP2 polymorphism and risk of development and metastasis of GCA were estimated by ORs and their 95% CIs, which were calculated by unconditional logistic regression models. Smokers were considered current smokers if they smoked
1 year before the date of diagnosis for cases or up to the date of the interview for controls. Information was collected on the amount of cigarettes smoked per day, the age at which the subjects started smoking, and the age at which ex-smokers stopped smoking. Light or heavy smokers were categorized by the
50th percentile pack-year value among controls, i.e., <26 or
26 pack-years [(cigarettes per day ÷ 20) x (years smoked)]. Because only 15 cases and 27 controls were ex-smokers, they were combined with current smokers for analysis. The ORs were adjusted for age, sex, and pack-years smoked. All analysis was carried out with Statistical Analysis System software (Version 6.12; SAS Institute, Cary, NC).
| RESULTS |
|---|
|
|
|---|
26 pack-years) between cases and controls was not significantly different (P = 0.97).
|
2 = 37.5, P = 0). None of the case subjects carried the TT genotype, whereas 2.3% of control subjects carried this genotype. Because the TT homozygotes were rare in our study, this genotype was combined with the CT genotype as the reference group for subsequent estimation of risk by using logistic regression analysis. It was found that the adjusted OR of developing GCA for the CC genotype compared with the CT and TT genotypes was 3.36 (95% CI 2.344.97).
|
26 pack-years (OR 3.91, 95% CI 1.878.11).
|
| DISCUSSION |
|---|
|
|
|---|
Our molecular epidemiological results are parallel to the laboratory findings showing that the 1306C
T transition in the promoter region of MMP2, which disrupts an Sp1-binding site (CCACC box), leads to a strikingly lower promoter activity with the T allele (11)
. Deletion or site-directed mutagenesis analysis of MMP2 promoter has also shown that the Sp1 site, among other promoter elements such as AP-2, is critical for constitutive activity of this gene (10)
. On the other hand, recent study also demonstrated that reduction of Sp1 DNA-binding activity or phosphorylation by nonsteroidal anti-inflammatory drugs suppresses MMP2 expression (16)
. Taken together, these data clearly suggest that the presence of Sp1 consensus sequence in the MMP2 1306C allele may enhance transcription, which in turn would produce higher levels of MMP-2 protein in individuals carrying the CC genotype than those carrying the TT or CT genotype. Because MMP-2 plays an important role in multiple ways to all stages of cancer initiation and development (see above), one would expect that individuals who carry the CC genotype and therefore have increased expression of this enzyme over a lifetime may be more susceptible to cancer. The association between high levels of constitutive expression of MMP-2 and susceptibility to tumor formation has been tested in several studies with genetically modified animals. It was found that when induced by carcinogenic stimulus, mice that lack the Mmp2 or Mmp9 gene developed fewer tumors than wild-type mice (17)
. Cancer cells injected via vein were found to be less capable of colonizing the lungs of Mmp2-knockout mice than lungs of wild-type mice (18)
. Conversely, transgenic mice that overexpress membrane type-MMP-1, a known activator of pro-MMP-2, were at increased susceptibility to mammary tumor formation and metastasis (19)
. These data strongly support our epidemiological observation that the genetic polymorphism resulting in high expression of MMP-2 over a lifetime may increase cancer susceptibility. In addition, functional polymorphisms in some other MMP genes have also been reported to be associated with risk of certain cancers, e.g., a single guanine insertion polymorphism in the MMP1 promoter region, which creates an Ets-binding site and enhances transcriptional activity, has been associated with increased risk for lung (20)
, colorectal (21
, 22)
, endometrial (23)
, and ovarian cancer (24)
. A single adenosine insertion polymorphism in the MMP3 promoter (6A allele), which has half the transcriptional activity of the 5A allele, has been linked to reduced susceptibility to breast cancer (25)
.
In this study, we found that the association between the MMP2 1306CC genotype and GCA risk appeared to be more pronounced in younger subjects (<60 years old). This finding is in line with the conception that genetic susceptibility is often associated with an early age of disease onset. We also found a significantly higher risk for GCA related to the MMP2 1306CC genotype among smokers and smokers who smoked
26 pack-years. Because the expression of MMPs can be induced by smoking (26
, 27) , one suggestive explanation of these findings is that, in addition to higher constitutive expression attributable to gain of an Sp1 promoter site, the inducibility by smoking of the C allele of MMP2 may also be higher than that of the T allele, which loses an Sp1 site. Given these conditions, it would be expected that smokers, especially heavy smokers, who carried the CC genotype were at the highest risk. Numerous studies have consistently shown that tobacco smoke may play an important role as an environmental etiological factor in the development of GCA (28, 29, 30, 31)
. Therefore, another explanation for a higher risk of GCA among smokers and heavy smokers with the CC genotype could be that these subjects had larger numbers of transformed cells caused by tobacco carcinogens in the target tissue, which consequently increases the possibility that one of these cells will form malignancy under the condition of higher MMP2 expression.
Local overexpression of MMP-2 has been shown to be correlated to invasion and metastasis of certain cancers, including gastroesophageal cancers (15 , 32 , 33) . Several studies have suggested that genetic polymorphism in the promoter of MMP1 (1G/2G) or MMP3 (5A/6A), which alters the transcription activity of the genes, may influence invasiveness or metastasis of some types of cancer, such as melanoma (34) , colorectal cancer (21) , and breast cancer (25) . In the present study, we did not find any significant association between MMP2 genotype and status of lymph node metastasis of GCA, questioning the major role of the CC genotype as a relevant genetic factor inducing the local overexpression of MMP-2 and as a risk marker of metastatic disease. However, these data on metastasis should be considered as preliminary data because of limited sample size and metastatic parameter. Additional examinations of larger patient series with more detailed clinicopathological features and clinic outcome, especially the survival rate, may be required.
Our study may have certain limitations because of the study design. Because it was a hospital-based, case control study and the cases were from the hospital and the controls were from the community, selection bias and/or systematic error may occur. It would therefore be important to confirm these findings in a population-based prospective study. In addition, excepting for tobacco smoking, other factors, such as gastroesophageal reflux disease, obesity, and certain dietary components, are known to be associated with risk of GCA (35 , 36) . These factors might interact with MMP2 genotype or act as potential confounders in the analysis. Unfortunately, information on these factors in our case control study is not available. It would be interesting to investigate the interaction between MMP2 genotype and these risk factors, especially gastroesophageal reflux disease on risk of GCA in additional studies.
In conclusion, our study provides the first evidence that the MMP2 -1306C/T polymorphism is a genetic susceptibility factor for the development of GCA, with the CC genotype being associated with increased risk of the cancer in Chinese population. This association is especially noteworthy in younger individuals and smokers. These results are consistent with our previous findings in the lung cancer study, further supporting the hypothesis that MMP-2 may play an important role in carcinogenesis. The MMP2 genotype seems not associated with the risk for metastatic of GCA, although additional studies are needed to clarify this important issue.
| FOOTNOTES |
|---|
1 Supported in part by Grants 39825122 and 39990570 from National Natural Science Foundation and Grant G1998051204 from State Key Basic Research Program. ![]()
2 X. M. and C. Y. contributed equally to this work. ![]()
3 To whom requests for reprints should be addressed, at Department of Etiology and Carcinogenesis, Cancer Institute, Chinese Academy of Medical Sciences, Beijing 100021, China. Phone: 86-10-677-22460; Fax: 86-10-677-13359; E-mail: dlin{at}public.bta.net.cn ![]()
4 The abbreviations used are: MMP, matrix metalloproteinase; DHPLC, denaturing high-performance liquid chromatography; OR, odds ratio; CI, confidence interval; GCA, gastric cardia adenocarcinoma. ![]()
Received 3/ 6/03. Accepted 5/ 2/03.
| REFERENCES |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
J. V. Cockle, N. Gopichandran, J. J. Walker, M. I. Levene, and N. M. Orsi Matrix Metalloproteinases and Their Tissue Inhibitors in Preterm Perinatal Complications Reproductive Sciences, October 1, 2007; 14(7): 629 - 645. [Abstract] [PDF] |
||||
![]() |
M. Sugimoto, S. Yoshida, S. Kennedy, M. Deguchi, N. Ohara, and T. Maruo Matrix Metalloproteinase-1 and -9 Promoter Polymorphisms and Endometrial Carcinoma Risk in a Japanese Population Reproductive Sciences, October 1, 2006; 13(7): 523 - 529. [Abstract] [PDF] |
||||
![]() |
R. F. Souza and S. J. Spechler Concepts in the Prevention of Adenocarcinoma of the Distal Esophagus and Proximal Stomach CA Cancer J Clin, November 1, 2005; 55(6): 334 - 351. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhou, C. Yu, X. Miao, Y. Wang, W. Tan, T. Sun, X. Zhang, P. Xiong, and D. Lin Functional haplotypes in the promoter of matrix metalloproteinase-2 and lung cancer susceptibility Carcinogenesis, June 1, 2005; 26(6): 1117 - 1121. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. Spitz, X. Wu, and G. Mills Integrative Epidemiology: From Risk Assessment to Outcome Prediction J. Clin. Oncol., January 10, 2005; 23(2): 267 - 275. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Zhang, X. Jin, S. Fang, Y. Li, R. Wang, W. Guo, N. Wang, Y. Wang, D. Wen, L. Wei, et al. The functional SNP in the matrix metalloproteinase-3 promoter modifies susceptibility and lymphatic metastasis in esophageal squamous cell carcinoma but not in gastric cardiac adenocarcinoma Carcinogenesis, December 1, 2004; 25(12): 2519 - 2524. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Miao, T. Sun, Y. Wang, X. Zhang, W. Tan, and D. Lin Functional STK15 Phe31Ile Polymorphism Is Associated with the Occurrence and Advanced Disease Status of Esophageal Squamous Cell Carcinoma Cancer Res., April 15, 2004; 64(8): 2680 - 2683. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhou, C. Yu, X. Miao, W. Tan, G. Liang, P. Xiong, T. Sun, and D. Lin Substantial reduction in risk of breast cancer associated with genetic polymorphisms in the promoters of the matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 genes Carcinogenesis, March 1, 2004; 25(3): 399 - 404. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |