Short tandem repeat polymorphism in a novel esophageal cancer-related gene (ECRG2) implicates susceptibility to esophageal cancer in Chinese population

ECRG2/SPINK7 Tumor Suppressor as Modulator of DNA Damage Response

Esophageal Cancer-Related Gene 2 (ECRG2), also known as Serine Peptidase Inhibitor Kazal type 7 (SPINK7), is a novel tumor suppressor gene from the SPINK family of genes that exhibits anticancer potential. ECRG2 was originally identified during efforts to discover genes involved in esophageal tumorigenesis. ECRG2 was one of those genes whose expression was absent or reduced in primary human esophageal cancers. Additionally, absent or reduced ECRG2 expression was also noted in several other types of human malignancies. ECRG2 missense mutations were identified in various primary human cancers. It was reported that a cancer-derived ECRG2 mutant (valine to glutamic acid at position 30) failed to induce cell death and caspase activation triggered by DNA-damaging anticancer drugs. Furthermore, ECRG2 suppressed cancer cell proliferation in cultured cells and grafted tumors in animals and inhibited cancer cell migration/invasion and metastasis. ECRG2 also was identified as a negative regulator of Hu-antigen R (HuR), an oncogenic RNA-binding protein that is known to regulate mRNA stability and the expression of transcripts corresponding to many cancer-related genes. ECRG2 function is important also for the regulation of inflammatory responses and the maintenance of epithelial barrier integrity in the esophagus. More recently, ECRG2 was discovered as one of the newest members of the pro-apoptotic transcriptional targets of p53. Two p53-binding sites (BS-1 and BS-2) were found within the proximal region of the ECRG2 gene promoter; the treatment of DNA-damaging agents in cancer cells significantly increased p53 binding to the ECRG2 promoter and triggered a strong ECRG2 promoter induction following DNA damage. Further, the genetic depletion of ECRG2 expression significantly impeded apoptotic cell death induced by DNA damage and wild-type p53 in cancer cells. These findings suggest that the loss of ECRG2 expression, commonly observed in human cancers, could play important roles in conferring anticancer drug resistance in human cancers. Thus, ECRG2 is a novel regulator in DNA damage-induced cell death that may also be a potential target for anticancer therapeutics.

Overview of Risk Factors for Esophageal Squamous Cell Carcinoma in China

(1) Background: China has the highest esophageal squamous cell carcinoma (ESCC) incidence areas in the world, with some areas of incidence over 100 per 100,000. Despite extensive public health efforts, its etiology is still poorly understood. This study aims to review and summarize past research into potential etiologic factors for ESCC in China. (2) Methods: Relevant observational and intervention studies were systematically extracted from four databases using key terms, reviewed using Rayyan software, and summarized into Excel tables. (3) Results: Among the 207 studies included in this review, 129 studies were focused on genetic etiologic factors, followed by 22 studies focused on dietary-related factors, 19 studies focused on HPV-related factors, and 37 studies focused on other factors. (4) Conclusions: ESCC in China involves a variety of factors including genetic variations, gene-environment interactions, dietary factors like alcohol, tobacco use, pickled vegetables, and salted meat, dietary behavior such as hot food/drink consumption, infections like HPV, poor oral health, gastric atrophy, and socioeconomic factors. Public health measures should prioritize genetic screening for relevant polymorphisms, conduct comprehensive investigations into environmental, dietary, and HPV influences, enhance oral health education, and consider socioeconomic factors overall as integral strategies to reduce ESCC in high-risk areas of China.

SPINKs in Tumors: Potential Therapeutic Targets

The serine protease inhibitor Kazal type (SPINK) family includes SPINK1-14 and is the largest branch in the serine protease inhibitor family. SPINKs play an important role in pancreatic physiology and disease, sperm maturation and capacitation, Nager syndrome, inflammation and the skin barrier. Evidence shows that the unregulated expression of SPINK1, 2, 4, 5, 6, 7, and 13 is closely related to human tumors. Different SPINKs exhibit various regulatory modes in different tumors and can be used as tumor prognostic markers. This article reviews the role of SPINK1, 2, 4, 5, 6, 7, and 13 in different human cancer processes and helps to identify new cancer treatment targets.

Cyclin D1 is a strong prognostic factor for survival in pancreatic cancer: analysis of CD G870A polymorphism, FISH and immunohistochemistry

BACKGROUND AND OBJECTIVE

Cyclin D1 is an important regulator protein for the G1-S cell cycle phase transition. The aim of this trial was to evaluate the impact of the CCND1 polymorphism G870A and corresponding protein expression and CCND1 amplification on the survival of the patients.

METHODS

425 patients with ductal pancreatic adenocarcinoma who underwent resection were included after histopathological confirmation. DNA was analyzed for Cyclin D1 polymorphisms, immunhistochemical examination and fluorescence in situ hybridization analysis of the tumor were performed.

RESULTS

Overall, the mean survival was 22.9 months (20.5-25.3). The survival in patients with Cyclin D1 G870A polymorphism Adenine/Adenine was 15.1 months (95% CI 11.3-18.9), 21.5 months (17.4-25.6) for Adenine/Guanine, and 29.4 months (95% CI 23.8-35.0) for Guanine/Guanine (P = 0.003). A shorter survival was associated with strong/moderate protein expression in immunohistochemistry (IHC) compared to weak/no expression (P = 0.028). Additionally, a significant coherency between unfavourable polymorphism (AA/AG) and increased protein expression was detected (P = 0.005).

CONCLUSIONS

A strong impact on survival of Cyclin D1 G870A polymorphism and the detected corresponding protein expression was found. The biological mechanism of CCND1 in carcinogenesis has not been fully examined; but at present Cyclin D1 seems to be an interesting biomarker for the prognosis of ductal adenocarcinoma.

Expression of bcl-2 and p53 in induction of esophageal cancer cell apoptosis by ECRG2 in combination with cisplatin

AIM

To investigate the mechanisms of induction of apoptosis of esophageal cancer cells by esophageal cancer-related gene 2 (ECRG2) in combination with cisplatin (DDP).

METHODS

Hoechest staining was performed to analyze the effects of single ECRG2 and ECRG2 in combination with DDP on apoptosis of EC9706 cells. The expression levels of p53 and bcl-2 mRNA and protein were determined by RT-PCR and Western blotting, respectively.

RESULTS

The number of apoptotic cells after the treatment with ECRG2 in combination with DDP for 24 hours was more than that after the treatment with single ECRG2. RT-PCR and Western blotting showed that the expression levels of bcl-2 mRNA and protein were both down-regulated, while p53 mRNA and protein were both up-regulated in the cells treated with ECRG2 in combination with DDP compared with those given ECRG2 alone.

CONCLUSION

ECRG2 in combination with DDP can enhance the apoptosis of EC9706 cells, possibly by down-regulating bcl-2 expression and up-regulating p53.

Effect of ECRG2 in combination with cisplatin on the proliferation and apoptosis of EC9706 cells

The aim of the present study was to explore the effect of esophageal cancer-related gene 2 (ECRG2) protein in combination with cisplatin (DDP) on the proliferation and apoptosis of esophageal cancer cells. A 3-(4, 5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay was used to examine the effects of ECRG2 alone and ECRG2 in combination with DDP on the proliferation of EC9706 esophageal cancer cells. Hoechst 33258 staining was performed to analyze the effects of ECRG2 alone and ECRG2 in combination with DDP on apoptosis in the EC9706 cells. The expression levels of Bcl-2-associated X protein (Bax) mRNA and protein were determined by reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The results from the MTT assay revealed that ECRG2 inhibited the proliferation of EC9706 cells and that ECRG2 in combination with DDP had a greater inhibitory effect on cell proliferation. The antiproliferative effects were time- and concentration-dependent, within a certain range of concentrations. The Hoechst 33258 staining results demonstrated that the number of apoptotic cells following treatment with ECRG2 in combination with DDP for 24 h was higher than that following treatment with ECRG2 alone for the same duration. Western blot analysis and RT-PCR results revealed that the expression levels of Bax mRNA and protein were upregulated in cells treated with ECRG2 in combination with DDP compared with those in cells treated with ECRG2 alone. Thus, ECRG2 in combination with DDP had an enhanced inhibitory effect on EC9706 cell proliferation compared with that of ECRG2 alone, and an increased inductive effect on EC9706 cell apoptosis, possibly due to the upregulation of the expression of Bax.

Progress in research of polymorphisms of genes associated with susceptibility to esophageal cancer in Chinese Han population

Esophageal squamous cell carcinoma (ESCC) is one of most common malignant tumors in China, and the polymorphisms of genes associated with susceptibility to ESCC are important factors affecting individual tumor susceptibility. Genes associated with susceptibility to ESCC in Chinese Han population mainly contain metabolizing enzyme-associated genes, nucleotide excision repair genes, methylenetetrahydrofolate reductase gene, tumor suppressor genes, oncogenes, and cytokines. The genotypes of genes associated with susceptibility to ESCC have obvious regional distribution in Chinese Han population. This review aims to summarize and analyze the polymorphisms of genes associated with susceptibility to ESCC, including tumor suppressor genes and genes encoding oncogenes and cytokines, in Chinese Han population.

Suppression of hepatocarcinoma model in vitro and in vivo by ECRG2 delivery using adenoviral vector

Hepatocarcinoma represents one of the most malignant cancer types. Esophageal cancer-related gene 2 (ECRG2) is found to be critical in the process of carcinogenesis. It regulates urokinase-type plasmin activator receptor and extracellular matrix function and its polymorphism in exon 4 is associated with cancer relapse. To explore new strategies to fight against cancer, here we first systematically evaluated the therapeutic potential as a biological tool using adenoviral vector (Ad-ECRG2). Ad-ECRG2 is exogenously expressed in cytoplasm and is potent to suppress the growth of cancer cell by inducing apoptosis as effective as Ad-p53. Ad-ECRG2 is able to suppress the invasion and adhesion of cancer cells at low titers. It alters the expression of a panel of cancer-related molecules, including nuclear factor-kB, matrix metalloproteinase 2 and E-cadherin, contributing to reverse malignancy phenotype of cancer cells. In vivo experiments show a significant inhibition of cancer growth by intratumoral Ad-ECRG2 administration. No evident toxicity was observed in the model animal during the study. We concluded that ECRG2 is a potential molecular target in biological therapy strategies for cancer treatment.

MicroRNA-1322 regulates ECRG2 allele specifically and acts as a potential biomarker in patients with esophageal squamous cell carcinoma

A short tandem repeat (STR) polymorphism in the 3'UTR region of esophageal cancer-related gene 2 (ECRG2, also known as SPINK7) has been widely reported to be associated with the incidence and the prognosis of esophageal squamous cell carcinoma (ESCC). This study explores how the microRNA binding to the STR region affects ECRG2 expression in ESCC. Dual-luciferase reporter assays were used to verify the effects of the four microRNAs (miR-580, miR-1182, miR-1272, and miR-1322) predicted to bind the STR region of the ECRG2 3' untranslated region (UTR). The expression of identified effective microRNA was then analyzed in 44 paired ESCC and adjacent normal tissues and 402 case-controlled serum samples (divided into a discovery group and an independent validation group) by real-time RT-PCR assay. We found that only miR-1322 could significantly down-regulate the ECRG2 with TCA3 allele (P < 0.01), but it could not down-regulate the ECRG2 with TCA4 allele significantly (P > 0.05). MiR-1322 was also expressed significantly higher in ESCC tissue and serum samples than in controls (both P < 0.01). Additionally, serum levels of miR-1322 yielded an under receiver operating characteristic (ROC) curve area of 0.847 (95% CI, 0.795-0.890) for discriminating ESCCs from healthy controls in the discovery group and a similar result was obtained in the validation group (under ROC area is 0.845; 95%CI, 0.780-0.897). We conclude that miR-1322 can regulate ECRG2 in an allele-specific manner and that serum levels of miR-1322 can serve as a potential diagnostic biomarker for patients with ESCC.

Northwestern China: a place to learn more on oesophageal cancer. Part two: gene alterations and polymorphisms

In the first part of this review, some behavioural and environmental risk factors playing important roles in the development of Kazakh's oesophageal squamous cell carcinoma (OSCC) were presented. Although all individuals have been exposed to the same environment and share the same behaviour, some of them will not develop OSCC. Thus, gene susceptibility and/or gene polymorphism are unavoidably involved. The molecular events underlying the initiation and progression of OSCC remain, however, poorly understood. In the second part of our review of OSCC in northwestern China, especially in the high-risk Kazakh population, some recent progress in the study of the molecular biology underlying oesophageal carcinogenesis, including chromosome deletions and loss of heterozygocity, polymorphisms of genes involved in xenobiotic metabolizing and DNA repair, and genetic alterations of transcriptional factors and apoptosis genes are presented. Results obtained in this high-risk population are compared with those obtained in other areas that are also known to be at high risk for OSCC, and whenever possible, with those studies performed in European, American or Australian low-risk areas. Recent advances in the investigation of the proteomics and microRNA biomarkers potentially useful for an earlier diagnosis and/or prognosis of OSCC are also discussed.

Association of mitochondrial haplogroup D and risk of esophageal cancer in Taihang Mountain and Chaoshan areas in China

Both the Taihang Mountain area in north-central China and Chaoshan area in the southeastern littoral of China are areas with high risk of esophageal cancer (EC). Our previous study confirmed that populations from the two areas might share similar matrilineal backgrounds and found that mitochondrial DNA (mtDNA) haplogroup D, especially subhaplogroups D4a and D5a, might be genetic background markers of EC in Chaoshan area. Here, to further determine whether D4a, D5a, and D might be susceptibility markers for EC in the two high-risk areas, we performed a case-control study with larger samples and analyzed the distributions of these three haplogroups in subjects (controls [n = 898] and patients [n = 768]) from the two areas. D4a haplogroup was significantly associated with increased risk of EC in Taihang Mountain subjects, especially women. D5 haplogroup was associated with EC at the general population level in the Taihang Mountain area and in subjects ≤ 60 years, especially women ≤ 60 years, in the Chaoshan area. D haplogroup was associated with EC only in subjects ≤ 60 years, especially men ≤ 60 years, in the Chaoshan area. D4a and D5 showing positive association with EC in the Taihang Mountain area became the predominant subhaplogroups of D in Chaoshan controls. In conclusion, D, D4a, and D5 haplogroups might be susceptibility markers for EC in the two high-risk areas in China, particularly D4a and D5 for the Taihang Mountain area and D and D5 for the Chaoshan area.

Genetic variations in esophageal cancer risk and prognosis

Investigations into inherited genetic variations in the DNA code (known as polymorphisms) in the field of oncology have provided preliminary support for an association with cancer risks and outcomes. Early studies have highlighted several genes with this potential predictive and prognostic power. However, these studies have had methodological limitations and have produced inconsistent results, making impractical as yet the routine evaluation of such genetic polymorphisms in general clinical practice. Continued research in this area is essential if we are to be able to soon use genetic polymorphisms to better select patients for targeted anticancer interventions. This review discusses the role of genetic polymorphisms and their association with esophageal cancer risk and prognosis. The article also highlights future directions in this new, emerging field of molecular epidemiology.

Polymorphism Arg290Arg in esophageal-cancer-related gene 1 (ECRG1) is a prognostic factor for survival in esophageal cancer

BACKGROUND

Esophageal cancer is one of the most frequent cancers worldwide and is associated with poor outcome. Besides clinicopathological data, few prognostic molecular markers exist. Esophageal-cancer-related gene1 (ECRG1) short tandem repeats are associated with higher risk for developing esophageal squamous cell carcinoma. The aim of the present study was to evaluate the impact of DNA polymorphisms in the coding region of ECRG1 in esophageal carcinoma.

METHODS

Genomic DNA of 107 patients with esophageal cancer that underwent complete surgical resection between 1997 and 2005 was extracted. DNA was analyzed for ECRG1 polymorphisms Arg290Arg, Arg290Gln, and Gln290Gln by PCR and gel electrophoresis. Polymorphisms were correlated with survival data by the Kaplan-Meier method, multivariate Cox regression analysis, and odds ratio were determined. For all variables, cross tables were generated, followed by calculation of the p value by using the chi-square test/Fisher-exact test.

RESULTS

Follow-up data of 102 patients with esophageal cancer were available after complete surgical resection for a median follow-up time of 24.3 months. Polymorphism Arg290Arg was found in 47 patients (46.1%), Arg290Gln in 48 patients (47.0%), and Gln290Gln in seven cases (6.9%). Arg290Arg polymorphism was significantly associated with reduced overall survival (p = 0.01) and tumor-free survival (p = 0.01) by the log-rank test. Multivariate regression analysis by Cox revealed polymorphism Arg290Arg to be a significant prognostic factor for survival (p = 0.012).

CONCLUSIONS

Polymorphism Arg290Arg in ECRG1 is associated with poor clinical outcome after complete surgical resection in patients with esophageal cancer.

Genetic polymorphisms and esophageal cancer risk

The aim of this paper is to review and evaluate, in a comprehensive manner, the published data regarding the contribution of genetic polymorphisms to risk of esophageal cancer, including squamous cell carcinoma (SCC) and adenocarcinoma, in humans. All relevant studies available in MEDLINE and published before February 2007 were identified. Studies carried out in humans and that compared esophageal cancer patients with at least 1 standard control group were considered for analysis. One-hundred studies and 3 meta-analyses were identified. Eighty (80%) studies were conducted in Asian countries, particularly China including Taiwan (60 (60%) studies). The most intensively examined genes were those encoding carcinogen metabolic enzymes. The most widely studied gene was GSTM1 (15 studies), followed by ALDH2 (11 studies). ALDH2, MTHFR C677T, CYP1A1 Ile/Val, CYP1A1MspI, CYP2E1, GSTP1, GSTM1 and GSTT1 were examined by meta-analyses and significant relations were found between ALDH2*1*2 and the CYP1A1 Val allele and increased risk of esophageal cancer. In addition, increased risk of esophageal SCC was consistently associated with the ADH2*1*2 and the p53 codon 72 Pro/Pro genotypes. Cohort studies that simultaneously consider multiple genetic and environmental factors possibly involved in esophageal carcinogenesis are needed to ascertain not only the relative contribution of these factors to tumor development but also the contributions of their putative interactions.

Short tandem repeat polymorphism in exon 4 of esophageal cancer-related gene 2 detected in genomic DNA is a prognostic marker for esophageal cancer

BACKGROUND

Short tandem repeat (STR) polymorphisms in exon 4 of the esophageal cancer-related gene 2 (ECRG2) are a risk marker for esophageal carcinoma. The aim of the present study was to correlate these STRs with clinical outcome.

METHODS

Genomic DNA of 86 patients who underwent complete surgical resection was analyzed for STRs TCA3/TCA3, TCA3/TCA4, and TCA4/TCA4 in exon 4 of ECRG2 by polymerase chain reaction and DNA sequencing.

RESULTS

ECRG2 STR TCA3/TCA3 and TCA3/TCA4 were found in 40 (47%) patients, respectively, and TCA4/TCA4 in 6 (7%) cases. TCA3/TCA3 genotype was significantly associated with reduced survival (P < .05, log-rank test). TCA3/TCA3 STR was the strongest prognostic factor determined by multivariate Cox regression analysis.

CONCLUSIONS

Genetically fixed STR polymorphism TCA3/TCA3 in exon 4 of ECRG2 is associated with poor clinical outcome in surgically treated esophageal cancer patients and might be a potential prognostic marker. The usefulness of these genetic markers to predict responsiveness toward neoadjuvant treatment of esophageal cancer patients would be of high clinical interest and should be examined in future studies.

Analysis of phenotype-genotype connection: the story of dissecting disease pathogenesis in genomic era in China, and beyond

DNA is the ultimate depository of biological complexity. Thus, in order to understand life and gain insights into disease pathogenesis, genetic information embedded in the sequence of DNA base pairs comprising chromosomes should be deciphered. The stories of investigating the association between phenotype and genotype in China and other countries further demonstrate that genomics can serve as a probe for disease biology. We now know that in Mendelian disorders, one gene is not only a dictator of one phenotype but also a dictator of two or more distinct disorders. Dissecting genetic abnormalities of complex diseases, including diabetes, hypertension, mental diseases, coronary heart disease and cancer, may unravel the complicated networks and crosstalks, and help to simplify the complexity of the disease. The transcriptome and proteomic analysis for medicine not only deepen our understanding of disease pathogenesis, but also provide novel diagnostic and therapeutic strategies. Taken together, genomic research offers a new opportunity for determining how diseases occur, by taking advantage of experiments of nature and a growing array of sophisticated research tools to identify the molecular abnormalities underlying disease processes. We should be ready for the advent of genomic medicine, and put the genome into the doctors' bag, so that we can help patients to conquer diseases.

Short tandem repeat polymorphism in exon 4 of esophageal cancer related gene 2 predicts relapse of oral squamous cell carcinoma

Short tandem repeat (STR) polymorphisms in exon 4 of esophageal cancer related gene 2 (ECRG2) are a prognostic marker for squamous cell carcinoma (SCC) of the esophagus. The aim of the present study was to correlate these STRs with clinical outcome of the similar tumor type oral squamous cell carcinoma (OSCC). DNA of 81 patients that underwent complete surgical resection of OSCC was analyzed for STRs TCA3/TCA3, TCA3/TCA4 and TCA4/TCA4 in exon 4 of ECRG2 by PCR, capillary electrophoresis and DNA sequencing. ECRG2 STR TCA3/TCA3 were found in 45 (56%), TCA3/TCA4 in 33 (41%) and TCA4/TCA4 in 3 (3%) patients. TCA3/TCA3 was significantly associated with reduced relapse-free survival of OSCC, compared with TCA3/TCA4 and TCA4/TCA4 genotypes (P<0.05; log-rank test). TCA3/TCA3 STR was independent prognostic factor determined by multivariate Cox regression analysis (p<0.05). STR polymorphism TCA3/TCA3 in exon 4 of ECRG2 is associated with poor relapse-free survival in surgically completely resected OSCC patients and might be a potential prognostic marker.

Monoclonal Antibodies to Esophageal Cancer–Related Gene2 Protein

Esophageal cancer related gene2 (ECRG2) acts as a bi-functional gene associated with regulation of cell growth and death, and plays an important role in carcinogenesis of esophageal cancer. RT-PCR and Northern blot data showed that ECRG2 was expressed in normal esophagus, liver, colon, and lung tissues, but lost or greatly down-regulated in the adjacent and cancerous tissues, especially in esophageal cancer. However, studies of protein have been hampered by the lack of a sensitive and specific antibody. Here, we generated anti-ECRG2 monoclonal antibodies (MAbs) by using c-terminal of ECRG2 peptide as immunogen. Antibodies 8C9c53, 5E3c9, and 3C5c76, are suitable for detecting the ECRG2 on ELISA and Western blot assays, and 1E4c2 and 4B6c41 are suitable for immunofluorescence microscopy. The study also provides novel data about ECRG2 protein expression in the cytoplasm and the possibility of post-translation modification in mammalian cells. Based on these findings, it may be expected that anti-ECRG2 monoclonal antibodies will be valuable tools for research and diagnosis.