Tumor Biol. DOI 10.1007/s13277-015-3125-8
RESEARCH ARTICLE
Association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and gastric cancer and metastasis M. Motovali-Bashi & M. Hamidy
Received: 11 September 2014 / Accepted: 19 January 2015 # International Society of Oncology and BioMarkers (ISOBM) 2015
Abstract HO-1 gene encodes heme oxygenase-1 enzyme that catalyzes the oxidation of heme to carbon monoxide (CO). It has also been suggested that cells could be protected by the enzyme against stress. A (GT)n dinucleotide repeat at HO-1 promoter is a polymorphic region and modulates gene transcription and associated with some of diseases. In this study, length of polymorphism GT tandem repeat has been determined and classified into two alleles short (≤28) and long (≥29). In present study, association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and increased risk of gastric cancer and metastasis was investigated. Blood samples from 100 control individuals and 60 gastric cancer cases had taken. Genotypic frequencies of (GT)n repeat for samples were determined using PCR technique and polyacrylamide PAGE electrophoresis. At final, higher frequency alleles were sequenced. Our results show that S-allele is significantly higher in cases in comparison with control groups (p= 0/000, odds ratio (OR)=4/154). It has been shown that individuals with S/S and S/L genotypes are at high risk of having gastric cancer (p=0/000, OR=3/789). Statistic data show association between SS genotype and risk of gastric cancer metastasis (p=0.017, OR=3.889). But, there is no significant association between clinicopathological characteristics of the patients and risk of gastric cancer metastasis (p>0.05). Significant association was found between short allele (SS + SL genotypes) and risk of gastric cancer, and also strong association was found between SS genotype and risk of gastric cancer metastasis. M. Motovali-Bashi (*) : M. Hamidy Genetic Division, Biology Department, Faculty of Sciences, University of Isfahan, Isfahan, Islamic Republic of Iran e-mail: [email protected] M. Motovali-Bashi e-mail: [email protected]
Keywords GT-repeat polymorphism . Heme oxygenase-1 promoter . Gastric cancer . Metastasis . Polyacrylamide PAGE
Introduction Although the worldwide incidence of gastric cancer is decreased, gastric cancer is still one of lethal cancers, and therefore, cancer detection in early stage is useful for patients’ treatment [15, 24]. In Iran gastric cancer incidence, diversity has been seen in different geographical regions; the northern and northwestern regions are high-risk areas, but southern and southeastern regions are low-risk areas [22]. Heme oxygenase (HO) was identified in 1969 by Tenhunen and Cohorts [30]. Human HO-1 gene is located at chromosome 22q12 and encodes 32-kDa inducible isoform enzyme that catalyzes heme cycle to biliverdin, carbon monoxide (CO), and free Fe2+ ion [20]. This enzyme plays a key role in cellular homeostasis constancy (heme metabolism) and protects cells against oxidative stresses. HO-1 enzyme is antiapoptosis and responsible for cancer cell resistance to apoptosis [7]. Dulak and coworkers demonstrated that the antiapoptotic and angiogenic effects of HO-1 are mediated through the ability of HO-1 to generate the CO by which carbon monoxide increases VEGF expression [5] and by which CO signaling pathway plays a key role in angiogenesis and tumor metastasis [28]. Also, overexpression of the HO-1 induces expression of MMP9, EGF, thymosin-β4, hyaluronidase-1, and malignant T cell amplified sequence-1 (MCT-1) in which way that strongly promotes cancer cell invasion and metastasis [11, 29]. HO-1 was also identified as an anti-inflammatory enzyme ([8], reviewed in [32]), because it decreases production of inflammatory cytokines which include the following: interleukin-1 β (IL-1β), interferon-γ (IFN-γ), tumor necrosis factor alpha (TNF-α),
Tumor Biol.
and IL-6 [1]. A (GT)n dinucleotide length polymorphism has been described that it is located on 5′ flanking region of the HO-1 gene promoter [17]. This microsatellite (GT dinucleotide tandem repeats) is very polymorph and often has many alleles. It is highly variable in the numbers of GT dinucleotide repeats, and therefore, it is useful for characterization of genetic diversity in human populations and investigation of association with diseases. The length polymorphism at promoter region is a negative regulatory element for gene expression [23], and for facility of investigations, it is classified into two S (short length) and L (long length) alleles [34, 6, 3]. In fact, there is no any distinct scale for allelic classification of the length polymorphism; for example, Yamada and coworkers have classified
RESEARCH ARTICLE
Association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and gastric cancer and metastasis M. Motovali-Bashi & M. Hamidy
Received: 11 September 2014 / Accepted: 19 January 2015 # International Society of Oncology and BioMarkers (ISOBM) 2015
Abstract HO-1 gene encodes heme oxygenase-1 enzyme that catalyzes the oxidation of heme to carbon monoxide (CO). It has also been suggested that cells could be protected by the enzyme against stress. A (GT)n dinucleotide repeat at HO-1 promoter is a polymorphic region and modulates gene transcription and associated with some of diseases. In this study, length of polymorphism GT tandem repeat has been determined and classified into two alleles short (≤28) and long (≥29). In present study, association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and increased risk of gastric cancer and metastasis was investigated. Blood samples from 100 control individuals and 60 gastric cancer cases had taken. Genotypic frequencies of (GT)n repeat for samples were determined using PCR technique and polyacrylamide PAGE electrophoresis. At final, higher frequency alleles were sequenced. Our results show that S-allele is significantly higher in cases in comparison with control groups (p= 0/000, odds ratio (OR)=4/154). It has been shown that individuals with S/S and S/L genotypes are at high risk of having gastric cancer (p=0/000, OR=3/789). Statistic data show association between SS genotype and risk of gastric cancer metastasis (p=0.017, OR=3.889). But, there is no significant association between clinicopathological characteristics of the patients and risk of gastric cancer metastasis (p>0.05). Significant association was found between short allele (SS + SL genotypes) and risk of gastric cancer, and also strong association was found between SS genotype and risk of gastric cancer metastasis. M. Motovali-Bashi (*) : M. Hamidy Genetic Division, Biology Department, Faculty of Sciences, University of Isfahan, Isfahan, Islamic Republic of Iran e-mail: [email protected] M. Motovali-Bashi e-mail: [email protected]
Keywords GT-repeat polymorphism . Heme oxygenase-1 promoter . Gastric cancer . Metastasis . Polyacrylamide PAGE
Introduction Although the worldwide incidence of gastric cancer is decreased, gastric cancer is still one of lethal cancers, and therefore, cancer detection in early stage is useful for patients’ treatment [15, 24]. In Iran gastric cancer incidence, diversity has been seen in different geographical regions; the northern and northwestern regions are high-risk areas, but southern and southeastern regions are low-risk areas [22]. Heme oxygenase (HO) was identified in 1969 by Tenhunen and Cohorts [30]. Human HO-1 gene is located at chromosome 22q12 and encodes 32-kDa inducible isoform enzyme that catalyzes heme cycle to biliverdin, carbon monoxide (CO), and free Fe2+ ion [20]. This enzyme plays a key role in cellular homeostasis constancy (heme metabolism) and protects cells against oxidative stresses. HO-1 enzyme is antiapoptosis and responsible for cancer cell resistance to apoptosis [7]. Dulak and coworkers demonstrated that the antiapoptotic and angiogenic effects of HO-1 are mediated through the ability of HO-1 to generate the CO by which carbon monoxide increases VEGF expression [5] and by which CO signaling pathway plays a key role in angiogenesis and tumor metastasis [28]. Also, overexpression of the HO-1 induces expression of MMP9, EGF, thymosin-β4, hyaluronidase-1, and malignant T cell amplified sequence-1 (MCT-1) in which way that strongly promotes cancer cell invasion and metastasis [11, 29]. HO-1 was also identified as an anti-inflammatory enzyme ([8], reviewed in [32]), because it decreases production of inflammatory cytokines which include the following: interleukin-1 β (IL-1β), interferon-γ (IFN-γ), tumor necrosis factor alpha (TNF-α),
Tumor Biol.
and IL-6 [1]. A (GT)n dinucleotide length polymorphism has been described that it is located on 5′ flanking region of the HO-1 gene promoter [17]. This microsatellite (GT dinucleotide tandem repeats) is very polymorph and often has many alleles. It is highly variable in the numbers of GT dinucleotide repeats, and therefore, it is useful for characterization of genetic diversity in human populations and investigation of association with diseases. The length polymorphism at promoter region is a negative regulatory element for gene expression [23], and for facility of investigations, it is classified into two S (short length) and L (long length) alleles [34, 6, 3]. In fact, there is no any distinct scale for allelic classification of the length polymorphism; for example, Yamada and coworkers have classified
