Potentially functional variants of PLCE1 identified by GWASs contribute to gastric adenocarcinoma susceptibility in an eastern Chinese population

Background

Recent genome-wide association studies (GWAS) have found a single nucleotide polymorphism (SNP, rs2274223 A>G) in PLCE1 to be associated with risk of gastric adenocarcinoma. In the present study, we validated this finding and also explored the risk associated with another unreported potentially functional SNP (rs11187870 G>C) of PLCE1 in a hospital-based case-control study of 1059 patients with pathologically confirmed gastric adenocarcinoma and 1240 frequency-matched healthy controls.

Methodology/Principal Findings

We determined genotypes of these two SNPs by the Taqman assay and used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CI). We found that a significant higher gastric adenocarcinoma risk was associated with rs2274223 variant G allele (adjusted OR = 1.35, 95% CI = 1.14–1.60 for AG+GG vs. AA) and rs11187870 variant C allele (adjusted OR = 1.26, 95% CI = 1.05–1.50 for CG+CC vs. GG). We also found that the number of combined risk alleles (i.e., rs2274223G and rs11187870C) was associated with risk of gastric adenocarcinoma in an allele-dose effect manner (P _trend = 0.0002). Stratification analysis indicated that the combined effect of rs2274223G and rs11187870C variant alleles was more evident in subgroups of males, non-smokers, non-drinkers and patients with gastric cardia adenocarcinoma. Further real-time PCR results showed that expression levels of PLCE1 mRNA were significantly lower in tumors than in adjacent noncancerous tissues (0.019±0.002 vs. 0.008±0.001, P<0.05).

Conclusions/Significances

Our results further confirmed that genetic variations in PLCE1 may contribute to gastric adenocarcinoma risk in an eastern Chinese population.     

食管鳞癌染色体及基因组DNA畸变研究进展

食管鳞癌是我国常见的消化道恶性肿瘤,进展快且预后差。由于早期一般无明显症状,临床确诊的食管鳞癌大多已发展到了中晚期,治愈难度较大。越来越多的证据表明,在食管鳞癌发生发展过程中,染色体及基因组DNA畸变均是最常见的遗传学改变。文章就食管鳞癌染色体及基因组水平异常的研究进展作一综述。     

食管鳞癌染色体及基因组DNA畸变研究进展

食管鳞癌是我国常见的消化道恶性肿瘤, 进展快且预后差。由于早期一般无明显症状, 临床确诊的食管鳞癌大多已发展到了中晚期, 治愈难度较大。越来越多的证据表明, 在食管鳞癌发生发展过程中, 染色体及基因组DNA畸变均是最常见的遗传学改变。文章就食管鳞癌染色体及基因组水平异常的研究进展作一综述。     

Tumor-suppressive microRNA-10a inhibits cell proliferation and metastasis by targeting Tiam1 in esophageal squamous cell carcinoma

Aberrant microRNAs (miRNAs) expressions could contribute to the progression of numerous cancers, including esophageal squamous cell carcinoma, while miR-10a participates in multiple biological processes on cancers. However, the molecular mechanism of miR-10a in esophageal squamous cell carcinoma (ESCC) has not been investigated. Herein, miR-10a was significantly reduced in ESCC clinical tissues and ESCC cell lines (EC109 and TE-3). In addition, immunohistochemistry indicated that the expressions of α-SMA, Ki-67, and PCNA in tumor tissues were higher than that of controls. In vitro, overexpression of miR-10a dramatically suppressed cell proliferation and enhanced cell apoptosis, while the decrease of miR-10a expressed the opposite outcome. Specially, overexpression of miR-10a caused a G0/G1 peak accumulation. Moreover, miR-10a also negatively regulated ESCC cell migration and invasion. Furthermore, targetscan bioinformatics predictions and the dual-luciferase assay confirmed that Tiam1 was a direct target gene of miR-10a. The statistical analysis showed Tiam1 was negatively in correlation with miR-10a in ESCC patient samples. And silencing Tiam1 could lead to a decline on cell growth, invasion, and migration in ESCC cell lines, while it could enhance cell apoptosis and cause a G0/G1 peak accumulation. In vivo, it revealed that miR-10a notably decreased the tumor growth and metastasis in xenograft model and pulmonary metastasis model. And it showed a lower expressions of Tiam1 in the miR-10a mimics group by immunohistochemistry. Taken together the results, they indicated that miR-10a might function as a novel tumor suppressor in vitro and in vivo via targeting Tiam1, suggesting miR-10a to be a candidate biomarker for the ESCC therapy.     

Inhibition of MUC1-C regulates metabolism by AKT pathway in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common digestive tumors worldwide. The Mucin 1 (MUC1) heterodimeric protein has been confirmed that is overexpressed in ESCC and induced adverse outcomes. However, the detailed mechanism(s) remained challenging. So, we investigated the relationship between MUC1-C and metabolism in ESCC cells. In the results, TP53-induced glycolysis and apoptosis regulator (TIGAR) was overexpressed and correlative with MUC1-C positively in ESCC tissue. Targeting MUC1-C inhibits AKT–mTORC–S6K1 signaling and blocks TIGAR translation. We found that the inhibitory effect of GO-203 on TIGAR was mediated by inhibition of AKT–mTOR–S6K1 pathway. The findings also demonstrated that the suppressive effect of GO-203 on TIGAR is related to the decrease of glutathione level, the increase of reactive oxygen species and the loss of mitochondrial transmembrane membrane potential. In xenograft tissues, GO-203 inhibited the growth of ESCC cells and lead to the low expression of transmembrane C-terminal subunit (MUC1-C) and TIGAR. This evidence supports the contention that MUC1-C is significant for metabolism in ESCC and indicated that MUC1-C is a potential target for the treatment of ESCC.     

食管鳞状细胞癌中DICKKOPF-3基因的甲基化状态及表达

目的检测食管鳞状细胞癌(esophageal squamous cell cancer,ESCC)中Wnt通路拮抗基因DICKKOPF-3(DKK3)的甲基化状态,探讨其与ESCC发生的关系。方法应用甲基化特异性PCR(methylation specificPCR,MSP)及RT-PCR的方法检测78例ESCC及相应癌旁非肿瘤组织中DKK3基因的甲基化状态及mRNA表达情况,应用免疫组化的方法检测通路中心因子-βcatenin蛋白及下游靶基因cyclinD1的表达,并分析其与食管癌发生的关系。结果在ESCC组织中,DKK3基因的甲基化频率为37.2%(29/78),明显高于癌旁非肿瘤组织(χ2=35.622,P=0.000);癌组织中该基因的甲基化率与肿瘤患者临床分期相关(χ2=4.705,P=0.030),而与组织学分级无关;食管癌中DKK3基因mRNA的阳性表达率为65.4%(51/78),明显低于癌旁非肿瘤组织(χ2=13.298,P=0.000)。在发生甲基化的食管癌组织中该基因的mRNA表达缺失及-βcatenin蛋白的异质表达率均明显高于未发生甲基化的癌组织,且差异有统计学意义(χ2mRNA=29.141,P=0.000;χ2-βcatenin=6.245,P=0.012)。食管癌中cyclinD1的表达明显高于癌旁组织,且癌组织中该蛋白的表达与DKK3基因的甲基化状态相关(χ2=4.921,P=0.027)。结论 ESCC组织中DKK3基因高甲基化导致的转录沉默可能与食管癌的发生有关,并可能通过活化Wnt/-βcatenin信号转导通路促进下游靶基因cyclinD1的过表达发挥作用。     

A functional variation in pre-microRNA-196a is associated with susceptibility of esophageal squamous cell carcinoma risk in Chinese Han

MicroRNAs (miRNAs) are small, non-protein-coding RNAs that function as tumour suppressors or oncogenes. A single nucleotide change in the sequence of pre-miRNA can affect miRNA expression, so single-nucleotide polymorphisms (SNPs) in pre-miRNA may be biomarkers for biomedical applications. In this study, we performed a genetic association study between the SNP (rs11614913) in pre-miRNA-196a and esophageal squamous cell carcinoma (ESCC) susceptibility in a case–control study. We found that the homozygote CC of this SNP increased the risk of ESCC compared with the homozygote TT and the risk was more evident among smokers than non-smokers. Therefore, this functional SNP may be a biomarker for ESCC outcome.     

Association of p53 and MDM2 polymorphisms with risk of human papillomavirus (HPV)-related esophageal squamous cell carcinoma (ESCC)

PurposeThough polymorphisms of the tumor suppressor gene p53 have been extensively investigated in numerous tumors, particularly tumors associated with human papillomavirus (HPV) infection. However, the results remain controversial. Our previous study showed that HPV serostatus is not an independent risk factor for esophageal squamous cell carcinoma (ESCC) in nonsmokers and nondrinkers. Given the roles of p53 and HPV E6 as well as MDM2 oncoproteins in p53 degradation, we validated the association of p53 and MDM2 polymorphisms with ESCC risk stratified by HPV16 sero-status.MethodsSingle nucleotide polymorphisms of p53 Arg72Pro (rs1042522) and MDM2 (rs937283) in 307 ESCC patients and 311 healthy controls were genotyped. The presence or absence of HPV16 in serum was measured by enzyme-linked immunosorbent assay. Multivariable logistic regression analysis was used to evaluate the possible associations of p53 and MDM2 polymorphisms with ESCC risk stratified by HPV16 sero-status.ResultsPatients carrying p53 Arg/Arg or Arg/Pro had a higher risk of esophageal SCC (P < 0.001, Odds ratio [OR] 4.98, 95% confidential interval [CI] 3.46–7.17), however, not found in MDM2 rs937283. The risk of esophageal SCC increased significantly among patients carrying p53 Arg/Arg, or Arg/Pro and HPV16-seropositivity (P < 0.001, OR 9.33, 95% CI 5.44–16.0), but not for MDM2 rs937283. The risk of esophageal SCC was further elevated among patients carrying Arg/Arg or Arg/Pro and HPV16-seropositivity who were smokers (P < 0.001, OR 27.05, 95% CI 11.06–66.16) or drinkers (P < 0.001, OR 13.20, 95% CI 5.74–30.38).ConclusionHPV16 seropositivity synergized with p53 Arg/Arg or Arg/Pro and increased ESCC risk, especially in smokers or drinkers.     

A functional germline variant in the P53 polyadenylation signal and risk of esophageal squamous cell carcinoma

Aim

P53 plays a critical role in the maintenance of genomic stability as well as the control of cell growth and apoptosis. Recently, an uncommon P53 genetic variant (rs78378222) was reported to be significantly associated with multiple cancers in Caucasians in a genome-wide association study. rs78378222 locates in the 3′-untranslated region of the P53 gene, and this A-to-C polymorphism results in changes of the AATAAA polyadenylation signal to AATACA, which leads to impaired 3′-end processing of P53 mRNA and decreased P53 expression.

Methods

We evaluated the association between this polymorphism and esophageal squamous cell carcinoma (ESCC) risk in a case–control cohort consisting of 405 ESCC patients and 810 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression.

Results

We did observe this polymorphism with low minor allele frequency in Chinese Han population. Additionally, significantly increased ESCC risk was associated with P53 rs78378222 A > C polymorphism. Compared with rs78378222AA carriers, the OR of developing ESCC for AC carriers was 3.22 (95% CI = 1.71 − 6.33, P = 1.34 × 10^− 4).

Conclusion

These results suggest that this functional uncommon P53 rs78378222 variant is associated with ESCC risk in the current Han Chinese population.     

The enhancement of radiosensitivity in human esophageal squamous cell carcinoma cells by zoledronic acid and its potential mechanism

Esophageal squamous cell carcinoma (ESCC) has a low 5-year patient survival rate. Radiotherapy, as a preoperative or postoperative treatment of surgery, has a crucial role in improving local control and survival of ESCC. Various chemotherapeutic and biologic agents have been used as radio-sensitizers in combination with radiotherapy. Here, we demonstrate that zoledronic acid (ZOL) has a radio-sensitizing effect on ESCC cells. Exposure of ESCC cancer cells to ZOL plus radiation resulted in increased cell death through arresting the cell cycle between S and G2/M phases. ZOL appeared to inhibit proliferation, tube formation and invasion of endothelial cells. These anti-angiogenetic effects were more marked concurrently with irradiation. In addition, synergistic suppressive effects on VEGF expression were observed after combined treatment. Our data suggest that the combination of ZOL and radiation is a promising therapeutic strategy to enhance radiation therapy for ESCC patients.     

A genetic variant in CDKN2A/2B locus was associated with poor prognosis in patients with esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is among the leading causes of cancer related death. Despite of extensive efforts in identifying valid cancer prognostic biomarkers, only a very small number of markers have been identified. Several genetic variants in the 9p21 region have been identified that are associated with the risk of multiple cancers. Here, we explored the association of two genetic variants in the 9p21 region, CDKN2A/B, rs10811661, and rs1333049 for the first time in 273 subjects with, or without ESCC. We observed that the patients with ESCC had a higher frequency of a TT genotype for rs10811661 than individuals in the control group, and this polymorphism was also associated with tumor size. Moreover, a CC genotype for the rs1333049 polymorphism was associated with a reduced overall survival (OS) of patients with ESCC. In particular, patients with a CC (rs1333049) genotype had a significantly shorter OS (CC genotype: 34.5 ± 8.9 months vs. CG+GG: 47.7 ± 5.9 months; p value = 0.03). We have also shown the association of a novel genetic variant in CDKN2B gene with clinical outcome of patients with ESCC. Further investigations are warranted in a larger population to explore the value of emerging markers as a risk stratification marker in ESCC.     

Overexpression of Aurora-A kinase promotes tumor cell proliferation and inhibits apoptosis in esophageal squamous cell carcinoma cell line

Attrora-A kinase, a serine/threonine protein kinase, is a potential oncogene. Amplification and overexpression of Aurora-A have been found in several types of human tumors, including esophageal squamous cell carcinoma （ESCC）. It has been demonstrated that cells overexpressing Attrora-A are more resistant to cisplatin-induced apoptosis. However, the molecular mechanisms mediating these effects remain largely unknown. In this report, we showed that overexpression of Attrora-A through stable transfection of pEGFP-Aurora-A in human ESCC KYSE150 cells significantly promoted cell proliferation and inhibited cisplatin- or UV irradiation-induced apoptosis. Cleavages of caspase-3 and poly （ADPribose） polymerase （PARP） in Attrora-A overexpressing cells were substantially reduced after cisplatin or UV treatment. Furthermore, we found that silencing of endogenous Aurora-A kinase with siRNA substantially enhanced sensitivity to cisplatin- or UV-induced apoptosis in human ESCC EC9706 cells. In parallel, overexpression of Aurora-A potently upregulated the expression of Bcl-2. Moreover, the knockdown of Bcl-2 by siRNA abrogated the Aurora-A＇s effect on inhibiting apoptosis. Taken together, these data provide evidence that Aurora-A overexpression promoting cell proliferation and inhibiting apoptosis, suggesting a novel mechanism that is closely related to malignant phenotype and anti-cancer drugs resistance of ESCC cells.     

MicroRNA-143 functions as a tumor suppressor in human esophageal squamous cell carcinoma

Esophageal cancer is one of the most common cancers worldwide with a poor prognosis. MicroRNAs(miRNAs) are a class of naturally occurring small noncoding RNAs and play an important role in cancer initiation and development. In this study, we demonstrate that the expression levels of miR-143 and miR-145 were significantly decreased in ESCC tissues in comparison with adjacent normal esophageal squamous tissues(NESTs). Furthermore, an inverse correlation between miR-143 and tumor invasion depth and lymph node metastasis was observed. The enforced expression of miR-143 induced growth suppression and apoptosis of ESCC cells. Rescue of miR-143 significantly suppressed the ESCC cells migration and invasion capabilities. Moreover, we show that functions of miR-143 in ESCC are mediated at least in part by the inhibition of extracellular signal regulated kinase-5(ERK-5) activity. These results prove that miR-143 may act as a tumor suppressor in ESCC.