Decreased expression and aberrant methylation of Gadd45G is associated with tumor progression and poor prognosis in esophageal squamous cell carcinoma

The growth arrest DNA damage-inducible gene (Gadd45) family, which is composed of Gadd45A, Gadd45B, and Gadd45G, is involved in DNA damage response and cell growth arrest. The present study was to detect the role of Gadd45 gene family in esophageal cancer and the relationship of Gadd45G methylation to a series of pathological parameters in a large esophageal squamous cell carcinoma (ESCC) sample, in order to elucidate more information on the role of Gadd45 gene family with regard to the pathogenesis of ESCC. Frequent silencing of Gadd45G but not Gadd45A and Gadd45B were found in esophageal cancer cell lines and the silencing of Gadd45G may be reversed by 5-Aza-dC or TSA treatment in Eca109 cell line. The aberrant proximal promoter methylation of Gadd45G induces silencing of Gadd45G expression in Eca109 cell line. Gadd45A mRNA and protein expression in ESCC tumor tissues was significantly different compared to corresponding normal tissues. Decreased mRNA and protein expression of Gadd45G was observed in ESCC tumor tissues and was associated with Gadd45G proximal promoter methylation. Gadd45A or Gadd45B expression was not correlated with ESCC patients survival, while Gadd45G methylation status and protein expression were independently associated with ESCC patients’ survival. These data indicated that Gadd45G may be a functional tumor suppressor and its inactivation through proximal promoter methylation may play an important role in ESCC carcinogenesis and reactivation of Gadd45G gene may has therapeutic potential and may be used as a prognostic marker for ESCC patients.     

Expression of Akt and Mdm2 in human esophageal squamous cell carcinoma

The Akt-Mdm2 pathway plays an important role in carcinogenesis in a variety of malignant tumors. However, the Akt-Mdm2 pathway in esophageal squamous cell carcinoma (ESCC) has not been fully studied. We investigated the proteins and mRNA expression of Akt and Mdm2 to elucidate the roles of these proteins in ESCC. We also examined the effect of Akt knockdown on Mdm2 expression in ESCC cells. ESCC tissue samples were obtained from 23 individuals who underwent surgical resection with no preoperative treatment. Akt1-3 and Mdm2 gene and protein expression were analyzed. The effect of siRNA-mediated Akt knockdown on Mdm2 expression was also studied, using ESCC cell lines. Akt1 and Mdm2 immunoreactivity was detected in 77.8 and 66.7% of tumor specimen from ESCC patients, respectively. Akt1 and Mdm2 mRNA expressions were correlated and significantly elevated in tumor tissue (p < 0.0001 and p < 0.05, respectively). The siRNA-targeted reduction of each Akt isoform reduced Mdm2 protein expression. The overexpression of Akt1 and Mdm2 may be related to esophageal carcinogenesis. Furthermore, Akt expression regulates Mdm2 expression, which may in turn regulate the function of wild-type p53. These results may provide the basis for future preventative or clinical therapies for esophageal cancer.     

Expression and prognostic value of FOXP1 in esophageal squamous cell carcinoma

BackgroundForkhead box protein P1 (FOXP1) has been suggested as a prognostic marker in several malignant tumors. However, the significance of FOXP1 in esophageal squamous cell carcinoma (ESCC) is still unclear. The purpose of this study was to investigate the expression pattern of FOXP1 in normal esophageal tissue and ESCC and to analyze the clinicopathological significance and prognostic value of FOXP1 in ESCC.MethodsFOXP1 was detected by immunohistochemistry using tissue microarrays containing tumor tissues and adjacent normal tissues from 270 ESCC patients with oncological follow-up data.ResultsNormal esophageal tissues predominantly showed an exclusive nuclear FOXP1 (n-FOXP1) expression pattern, and no exclusive cytoplasmic FOXP1 (c-FOXP1) staining was found. In ESCC, the expression rates of exclusive n-FOXP1-positive, exclusive c-FOXP1-positive, both nuclear and cytoplasmic positive and complete negative were 14.4%, 28.9%, 10.4% and 46.3%, respectively. High n-FOXP1 expression was significantly correlated with decreased postoperative recurrence and distant metastasis (P < 0.05). Furthermore, elevated c-FOXP1 expression was significantly associated with regional lymph node metastasis and distant metastasis (P < 0.05). High c-FOXP1 expression had an effect on shorter overall survival (OS) time, but the difference was not statistically significant (P > 0.05). Kaplan–Meier analysis showed that ESCC patients with high n-FOXP1 expression survived significantly longer than patients with low n-FOXP1 expression. Multivariate analysis confirmed that patients with high n-FOXP1 staining exhibit good prognosis and n-FOXP1 was an independent factor for ESCC prognosis.ConclusionsOur results suggest that FOXP1 plays an essential role in ESCC progression and prognosis and may be a useful biomarker for predicting survival.     

食管鳞癌组织中TIG1基因甲基化及其mRNA表达的研究

 目的：探讨他扎罗汀诱导基因1（tazarotene-induced gene-1, TIG1）基因甲基化及表达与食管鳞癌发生、发展的关系。方法：采用甲基化特异性PCR检测43例食管鳞癌组织、20例癌旁组织和15例正常组织中TIG1基因甲基化状态;实时荧光定量PCR法法检测TIG1 mRNA的表达。结果：食管鳞癌组织TIG1基因启动子甲基化率为25.6%（11/43）,癌旁组织5.0%（1/20）,正常组织中未检测到其甲基化,差异有统计学意义（P<0.05）;其甲基化水平与患者性别、年龄、肿瘤生长部位和分化程度无关（P>0.05）,但与患者TNM分期（P<0.01）及淋巴结转移（P<0.05）有关。鳞癌组织TIG1 mRNA显著低于癌旁组织（P<0.05）及正常组织（P<0.01）,甲基化组织TIGI mRNA表达显著低于非甲基化组织（P<0.01）。结论：甲基化可能是食管鳞癌中TIG1基因失活的重要机制,与患者病理分期及淋巴结转移有关。     

Quantitative evaluation of SPRR3 expression in esophageal squamous cell carcinoma by qPCR and its potential use as a biomarker

Esophageal squamous cell carcinoma (ESCC) is highly fatal due to late diagnosis and inefficient treatment. Early disease detection could improve diagnosis and patient survival. Esophageal squamous epithelial cells express SPRR3, a member of the small proline-rich protein family, which is downregulated in ESCC. Therefore, SPRR3 expression may be used as a biomarker to follow the transition from healthy mucosa to ESCC. Both SPRR3 mRNA splice variants, v1 and v2, were evaluated by real time PCR in tumor and histologically normal adjacent tissue biopsies from 84 ESCC patients and 18 healthy controls. SPRR3-v1 was most highly expressed in the esophageal mucosa of healthy subjects, with an increasingly lower expression in the adjacent mucosa of ESCC patients and in tumors, respectively. SPRR3-v2 expression was low in normal mucosa and in tumors but it was higher in the adjacent mucosa of ESCC patients. In addition, we found a significant correlation between a lower SPRR3-v1 and SPRR3-v2 expression and age and alcohol consumption, respectively. SPRR3 protein expression presented a good correlation with SPRR3 mRNA expression. Cut-off points to discriminate between healthy mucosa, tumor and adjacent mucosa were determined with receiver operating characteristic (ROC) curves. This analysis showed that SPRR3-v1 expression discriminates the esophageal mucosa of healthy subjects from the adjacent mucosa and the tumor of ESCC patients with high sensitivity and specificity. Our data shows that the quantitative analysis of SPRR3 mRNA is a robust and reliable method to monitor the malignant transformation of the healthy esophageal mucosa into ESCC.     

Prognostic value of ISG15 mRNA level in drinkers with esophageal squamous cell cancers

ISG15, the protein encoded by interferon (IFN)-stimulated gene 15, was the first identified ubiquitin-like protein, which could be strongly upregulated by type I interferons as a primary response to diverse microbial and cellular stress stimuli. Although the biological activities of ISG15 have yet to be fully elucidated, it is frequently overexpressed in various cancers. As the role of ISG15 in esophageal squamous cell cancer (ESCC) has not been well reported, the current study aimed to elucidate the role of ISG15 in predicting outcomes of ESCC patients. Samples were collected from 153 ESCC patients, including 54 pairs of tumor tissues and non-tumor tissues. Compared with the paired non-tumor tissues, higher expression of ISG15 mRNA were detected in ESCC tissues. The cut-off value 1.28 determined by ROC curve analysis divided the ESCC patients into high and low ISG15 mRNA expression group. High-ISG15 mRNA expression appeared with more frequency in ever-drinkers (P = 0.018). Kaplan-Meier analysis indicated that Low-ISG15 mRNA expression group had a longer cancer-specific survival (CSS) compared with High-ISG15 mRNA expression group. Multivariate analysis revealed that ISG15 mRNA (P = 0.024; hazard ratio, 2.759, 95% CI, 1.841-4.134) as well as Pathological staging (P < 0.001; hazard ratio, 1.634, 95% CI, 1.065-2.505) were independent prognostic factors. Subgroup analysis revealed that the discernibility of ISG15 mRNA level on ESCC outcomes was only pronounced in ever-drinkers (P = 0.026) not in never-drinkers (P = 0.138). ISG15 might serve as a novel prognostic biomarker in drinkers with ESCC.     

Expression of Wnt11 and Rock2 protein with clinical characteristics of esophageal squamous cell carcinoma in Kazakh and Han patients

Background: Esophageal squamous cell carcinoma (ESCC) is one of the most malignancies with a very poor outcome in China. Wnt11 and Rock2, new identified proteins highly associated with metastasis of many cancers, which were never reported in esophageal squamous cell carcinoma (ESCC). Here we measured the expression levels of Wnt11 and Rock2 in tissues from 265 patients with ESCC. Immunohistochemical staining was employed to detect the correlation of Wnt11 and Rock2 expression with clinicopathological features. Methods: The expression of Wnt11 and Rock2 was detected by immunohistochemistry in esophageal squamous cell carcinomas and normal esophageal tissues. A chi-square test was used to assess the statistical significance of the correlations between Wnt11, Rock2 expression and different clinicopathological parameters, respectively. Results: The high-expression of Wnt11 and Rock2 was observed in ESCCs. Seventy-five cases of ESCC (51.7%) showed a positive expression of Wnt11, which indicated a significant association with the AJCC stage (P=0.007). Ninety-eight cases of ESCC (65.5%) showed a positive expression of Rock2, which indicated a significant association with ethnic background. There were no close correlations between Rock2 expression and gender, tumor location, AJCC stage, lymph node metastasis. Specifically, the expression of Rock2 was significantly different between Hans and Kazaks ethnicities (P=0.000). In Kaplan-Meier curve analysis, no significant correlation was observed between the expression of Wnt11, Rock-2 and the poor prognosis of ESCCs. Conclusion: Our finding suggests that the over-expression of Rock2 may play an important role in the carcinogenesis and progression, and may become a new underlying molecular marker in the diagnosis and treatment in ESCC.     

microRNA-155 acts as an oncogene by targeting the tumor protein 53-induced nuclear protein 1 in esophageal squamous cell carcinoma

MicroRNA-155 (miR-155) is overexpressed in many human cancers; however, the function of miR-155 is largely unknown in esophageal squamous cell carcinoma (ESCC). In the present study, we found that miR-155 is dramatically increased in ESCC tissues compared with the paired adjacent normal tissues, which suggested that miR-155 acts as an oncogene in ESCC. We predicted that tumor protein p53-induced nuclear protein 1 (TP53INP1) is a candidate target gene of miR-155 given that miR-155 expression decreased mRNA and protein levels of TP53INP1 as determined by RT-PCR and Western blot analysis. In addition, miR-155 and TP53INP1 showed a negative relation in ESCC tissues. Dual luciferase-based reporter assay indicated direct regulation of TP53INP1 by miR-155. Furthermore, we demonstrated that RNA interference of TP53INP1 increased the proliferation and colonies formation of EC-1 cells. Up-regulation of TP53INP1 abrogated miR-155 induced growth in EC-1 cells and mutation of TP53INP1 in 3’-UTR restored the effects when co-transfected with miR-155. We also indicated that overexpression of miR-155 significantly promoted the proliferation of EC-1 cells in vitro and the development of tumors in nude mice. Taken together, our study reveals that miR-155 acts as an oncogene by targeting TP53INP1 in ESCC.     

Expression of RKIP,E-cadherin and NF-kB p65 in esophageal squamous cell carcinoma and their correlations

To detect the expression of RKIP, E-cadherin and NF-kB p65 in esophageal squamous cell carcinoma (ESCC) and study their correlations. Steptavidin-peroxidase (S-P) method was employed to detect the expressions of RKIP, E-cadherin and NF-kB p65 in ESCC tissues from 77 cases and paracancerous tissues from 77 cases. The correlations between their expressions and clinicopathological indices and between the expressions of these proteins themselves were analyzed. The expressions of RKIP and E-cadherin in ESCC tissues were obviously lower than those in the paracancerous tissues (P<0.01); the expressions in ESCC tissues from cases with lymph node metastasis were lower than those from cases without lymph node metastasis (P<0.01); the expression of RKIP was positively correlated with the expression of E-cadherin in ESCC tissues (P<0.01). The expression of NF-kB p65 in ESCC tissues was correlated with clinical staging, lymph node metastasis and tumor differentiation (P<0.01); the expression of RKIP was negatively correlated with the expression of NF-kB p65 in ESCC tissues (P<0.05). Downregulation or depletion of RKIP was related to the onset and progression of ESCC, and facilitated the invasion and metastasis of ESCC by downregulating E-cadherin and upregulating NF-kB p65.     

Increased expression of HMGB3: a novel independent prognostic marker of worse outcome in patients with esophageal squamous cell carcinoma

HMGB3, an X-linked member of the high-mobility group (HMG) superfamily of HMG proteins, has been shown to affect numerous tumorigenic progression. However, the expression and the prognostic role of HMGB3 in esophageal squamous cell carcinoma (ESCC) remained unknown. In this study, we examined the HMGB3 expression in ESCC tissues and adjacent nontumorous tissues by qRT-PCR and immuohistochemistry. Statistical analyses were applied to test for prognostic and diagnostic associations. The mRNA levels of HMGB3 were found to be significantly higher in tumorous tissues than in the adjacent normal tissues. We found that the HMGB3 expression was higher in tumorous tissues than in the adjacent non-tumorous tissues by immunohistochemical analysis of paired tissue specimens (P < 0.001). Moreover, there was a significant correlation between HMGB3 expression and gender (P = 0.037), clinical stage (P = 0.038), T classification (P = 0.013) and N classification (P = 0.017). Patients with higher HMGB3 expression had shorter overall survival than those with lower HMGB3 expression. Multivariate Cox analysis indicated that HMGB3 expression is an independent prognostic factor for overall survival (HR = 0.591, 95% CI = 0.379-0.793, P = 0.039). In summary, these findings demonstrate that HMBG3 may be a potential molecular marker for predicting the prognosis of ESCC patients.     

Increased level of serum prostaglandin-2 in early stage of esophageal squamous cell carcinoma

Introduction

Prostaglandin-2 (PGE-2), one of the products of cyclooxygenase-2 (COX-2) induced catalysis, may play a critical role in the carcinogenesis of esophageal squamous cell carcinoma (ESCC). We investigated the efficacy of using serum PGE-2 concentration as a biomarker for this cancer type.

Material and methods

Prostaglandin-2 levels were analyzed in the serum of 65 ESCC patients and in 47 healthy individuals. The concentrations of cyclooxygenase-2 (COX-2) were measured in tumor tissues and normal tissues obtained from 31 surgically treated ESCC patients.

Results

Serum PGE-2 concentration was significantly higher in ESCC patients than in control patients (p = 0.004), especially in the early stages (I + II) of cancer (p < 0.0001). We observed significant inverse relationships between serum PGE-2 levels and: tumor stage, primary tumor progression, lymph and distant metastasis. The COX-2 concentration was significantly elevated in tumors as compared to normal tissues (p = 0.008). A significant correlation between serum PGE-2 and tumor COX-2 was observed (rho = 0.46, p = 0.009). However, ROC analysis showed that serum PGE-2 may be a weak prognostic factor for ESCC.

Conclusions

Our results suggest that an elevated concentration of serum PGE-2 in the early stages of cancer may possibly be associated with tumor initiation and cancer development in ESCC. The exact role of these findings in early detection of this highly lethal cancer requires further research.     

RANK overexpression as a novel esophageal cancer marker: validated immunohistochemical analysis of two different ethnicities

This study aimed to evaluate the receptor activator of nuclear factor-κB (RANK) expression statuses of esophageal squamous cell carcinoma (ESCC) patients, high-grade intraepithelial neoplasia (HGIN), low-grade intraepithelial neoplasia (LGIN), and normal esophageal tissues (NETs) in Chinese Han and Kazakh ethnic, as well as the correlation of RANK expression with clinicopathological characteristics. RANK immunohistochemical analysis was conducted to investigate the expression of RANK in 113 ESCC, 36 HGIN, 63 LGIN, and 98 NETs from Han ethnic patients and in 196 ESCC and 76 NETs from Kazakh ethnic patients. The associations of RANK expression with ethnic and clinicopathological characteristics were examined using χ²-test. Upregulated RANK expression was detected in both Han and Kazakh ethnic ESCC tissues, compared with NETs (P = 1.11×10^-5, 0.001, respectively). RANK expression was significantly increased during malignant transformation from normal epithelium into LGIN (P = 2.84×10^-7) and HGIN (P = 7.83×10^-6) tissues in Han ethnic patients. The increased expression of RANK also correlated with lymph node metastasis in Kazakh ethnic ESCC patients (P = 0.019). By contrast, no significant correlation existed between RANK expression and clinicopathological characteristics of Han ethnic ESCC patients. Furthermore, Kaplan-Meier survival analysis showed that ESCC patients with higher expression of RANK protein had significantly worse prognosis than ESCC patients with low or no expression (P = 0.001). In conclusion, this study is the first to identify RANK overexpression as a novel esophageal cancer marker in both Kazakh and Han ethnic ESCC patients. The results support the association of RANK with ESCC across ethnicities. In summary, RANK could be a therapeutic target in ESCC patients.     

Overexpression of PLCE1 in Kazakh esophageal squamous cell carcinoma: implications in cancer metastasis and aggressiveness

Three recent large‐scale genome‐wide association studies (GWAS) in Chinese Han populations have identified an esophageal squamous cell carcinoma (ESCC) susceptibility locus within phospholipase C epsilon 1 (PLCE1) gene, which encodes a phospholipase involved in intracellular signaling. The expressed PLCE1 in ESCC, however, are inconsistent. This study examined PLCE1 expression by immunohistochemistry (IHC) from 110 ethnic Kazakh ESCC patients and 50 from adjacent normal esophageal tissues (NETs). The expressed PLCE1 was localized in cytoplasm, especially in the peripheral layers of cancer cell nests, which was significantly higher in tumors than in NETs (p < 0.001). Increased expression of PLCE1 was correlated with advanced tumor‐node‐metastasis (TNM) stages (p = 0.015) and lymph node metastasis (p = 0.003) in patients with ESCC. Of the 110 patients, we examined 50 paired ESCC tissues and corresponding NETs by quantitative RT‐PCR (polymerase chain reaction) and the mean mRNA level of PLCE1 in ESCC was 1.85‐fold higher compared with those in corresponding NETs (p = 0.0012). Meanwhile, 4 of 5 ESCC cell lines also showed elevated expression of PLCE1 mRNA. Furthermore, elevated expression of PLCE1 mRNA in Kazakh ESCC was associated with its immunoreactivity (ρ = 0.297, p = 0.040), lymph node metastasis (p < 0.001), and advanced TNM stages of ESCC (p = 0.013). To our knowledge, this study demonstrates for the first time that PLCE1 overexpression correlates with lymph node metastasis and advanced TNM stages of Kazakh ESCC, implicating a role of PLCE1 in cancer metastasis and aggressiveness in ethnic Kazakh patients with ESCC. Furthermore, the current findings may warrant investigations into whether inhibiting PLCE1 could be a strategy for targeted anticancer therapy particularly for Kazakh ESCC.