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

Exploring the hub genes and mechanisms of Daphne altaica treating esophageal squamous cell carcinoma based on network pharmacology and bioinformatics analysis

PURPOSE

Esophageal squamous cell carcinoma (ESCC), is a frequent digestive tract malignant carcinoma with a high fatality rate. Daphne altaica (D. altaica), a medicinal plant that is frequently employed in Kazakh traditional medicine, and which has traditionally been used to cure cancer and respiratory conditions, but research on the mechanism is lacking. Therefore, we examined and verified the hub genes and mechanism of D. altaica treating ESCC.

METHODS

Active compounds and targets of D. altaica were screened by databases such as TCMSP, and ESCC targets were screened by databases such as GeneCards and constructed the compound-target network and PPI network. Meantime, data sets between tissues and adjacent non-cancerous tissues from GEO database (GSE100942, GPL570) were analyzed to obtain DEGs using the limma package in R. Hub genes were validated using data from the Kaplan-Meier plotter database, TIMER2.0 and GEPIA2 databases. Finally, AutoDock software was used to predict the binding sites through molecular docking.

RESULTS

In total, 830 compound targets were obtained from TCMSP and other databases. In addition, 17,710 disease targets were acquired based on GeneCards and other databases. In addition, we constructed the compound-target network and PPI network. Then, 127 DEGs were observed (82 up-regulated and 45 down-regulated genes). Hub genes were screened including TOP2A, NUF2, CDKN2A, BCHE, and NEK2, and had been validated with the help of several publicly available databases. Finally, molecular docking results showed more stable binding between five hub genes and active compounds.

CONCLUSIONS

In the present study, five hub genes were screened and validated, and potential mechanisms of action were predicted, which could provide a theoretical understanding of the treatment of ESCC with D. altaica.

Tumor-infiltrating lymphocyte signature in epithelial and stromal compartments of an esophageal squamous cell carcinoma acidic microenvironment mediated by MCT4

Tumor-infiltrating lymphocytes (TILs), including but not limited to neutrophils, M2 macrophages, cytotoxic CD8 T cells and dendritic cells, will play a role in the acidic tumor microenvironment mediated by monocarboxylate transporter 4 (MCT4) in esophageal squamous cell carcinoma (ESCC). However, the roles they play and their significance in ESCC remain less clear. To understand the clinicopathological and prognostic significance of neutrophils, M2 macrophages, CD8 T cells and dendritic cells in the tumor acidic microenvironment mediated by MCT4, we investigated the distribution of these TILs in the epithelial and stromal compartments of ESCC by means of multiplexed immunohistochemistry on a tissue microarray containing 87 paired dots of ESCC and its adjacent normal tissue (ANT) and an additional 6 cases of unpaired ESCC dots. The density of cells stained with MCT4 in the epithelium was significantly associated with overall survival. Dendritic cells stained with S100 in epithelial compartmentalization were found to markedly correlate with clinical stage and tumor invasion depth. No other significant association could be identified in terms of prognostic and clinicopathological significance. The potential correlation between the number of cells stained with MCT4 versus the number of TILs was also explored, showing that only in epithelial cells were there significant and positive correlations identified between the number of cells stained with MCT4 versus the number of neutrophils stained with CD15, M2 macrophages stained with CD163 and CD8 T cells stained by CD8a. However, no significant correlation was found along the stromal line. Together, the data we described here, although somewhat discouraging, showed that in epithelial cells from which ESCC originated, acidicity mediated by MCT4 may be responsible for lactate release and may have an effect on the infiltration of TILs we assessed.

Risk factors for esophageal cancer in a high-incidence area of Malawi

PURPOSE

To explore associations of nutritional, infectious, and lifestyle factors with esophageal cancer (EC) occurrence in a high-risk area of Malawi.

METHODS

This case-control study was performed with 227 patients undergoing endoscopy for dysphagia or other upper gastrointestinal complaints. Data on clinicopathological characteristics and risk factors were collected using a questionnaire developed for this study specifically. Ninety-eight blood samples were collected and the prevalence of antibodies against human immunodeficiency virus, herpes simplex virus, cytomegalovirus, Epstein-Barr virus, varicella-zoster virus, and Helicobacter pylori were determined serologically.

RESULTS

The tumor and control groups comprised 157 (69.2%) and 70 (31.8%) patients, respectively. Patients with tumors were significantly older than controls (55.5 vs. 43.5 years, p < 0.001). The male/female ratio did not differ between groups (59% and 54% male, respectively; p = 0.469). EC was associated with smoking (p < 0.001), and alcohol consumption (p = 0.020), but 43% of patients with tumors did not smoke or drink. EC was associated with the consumption of hot food and tea (p = 0.003) and smoked fish (p = 0.011). EC was not associated with any serologically investigated infectious agents. In an age adjusted binary logistic regression analysis of all nutritive factors, only locally made alcohol was significant [odds ratio (OR), 9.252; 95% confidence interval (CI), 1.455-58.822; p = 0.018].

CONCLUSIONS

Apart from alcohol consumption and smoking, the consumption of hot food or tea and smoked fish are associated with EC. Locally distilled alcohol consumption increases the EC risk in Malawi.

Expression of Twist, Slug and Snail in esophageal squamous cell carcinoma and their prognostic significance

Esophageal cancer is one of the most common types of malignancy worldwide. At present, surgical resection is the main treatment for esophageal cancer, but recurrence and distant metastasis are the main causes of mortality. The transcription factors Twist, Slug and Snail regulate epithelial-mesenchymal transition and thereby participate in tumor invasion and metastasis. The aim of the present study was to investigate the expression of Twist, Slug and Snail in esophageal squamous cell carcinoma (ESCC) and their prognostic significance. The expression of Twist, Slug and Snail in 229 paraffin-embedded ESCC and matched normal mucosal tissues was detected by immunohistochemistry. The expression differences of Twist, Slug and Snail in the ESCC and normal tissues were compared by χ² test, and the associations between the three proteins and the clinicopathological parameters of ESCC were analyzed. The expression levels of Twist, Slug and Snail in 29 fresh frozen ESCC and matched normal mucosal tissues were detected by reverse transcription-quantitative PCR. The correlations among Twist, Slug and Snail in ESCC were examined by Pearson's correlation analyses. In addition, single factor and multivariate Cox regression analyses were used to analyze the influence of Twist, Slug and Snail on the prognosis of ESCC. Twist was found to be highly expressed in ESCC. The difference of Slug expression in ESCC was associated with differentiation degree, TNM stage and vascular invasion, but no significant association was observed between Snail expression and any clinicopathological parameters. In ESCC, there were significant differences in protein expression between Twist and Snail, and Slug and Snail. The mRNA expression level of Twist in ESCC was significantly higher than that in normal esophageal mucosa. However, the mRNA expression of Slug in normal esophageal mucosa was higher than that in ESCC, and the mRNA expression levels of Twist and Snail were positively correlated in ESCC. Kaplan-Meier analysis of 229 patients with ESCC revealed that Snail influenced the overall survival, as did the co-expression of Twist and Snail. Nerve invasion was also identified as an independent factor affecting the progression-free survival of ESCC. The results indicate that Twist is highly expressed, Slug may be a tumor suppressor, and Snail is an independent prognostic factor in ESCC. Twist and Snail are positively correlated, and the simultaneous inhibition of Twist and Snail protein expression may be beneficial for prolonging the overall survival of patients with ESCC.

MicroRNA and target mRNA selection through invasion and cytotoxicity cell modeling and bioinformatics approaches in esophageal squamous cell carcinoma

This study analyzed microRNA (miRNA) and mRNA expression profiles and investigated the biological characteristics of ESCC by using invasion and cytotoxicity cell models. miRNA profiles were evaluated through miRNA microarray. Transwell chamber and nedaplatin (NDP) were used to construct invasion and cytotoxicity cell models. Invasion Transwell and cytotoxicity assays were performed to examine the invasiveness and proliferation in the cell models. Functional miRNAs were selected from dysregulated miRNAs through qRT-PCR. Biometric Research Program (BRB)-array tools, Cytoscape plugins, and DAVID were utilized to find potential mRNAs targeted by these two miRNAs between ESCC and paired normal adjacent tissues. Our microarray obtained 11 dysregulated miRNAs expressed in three paired ESCC samples from Kazakhs (ethnicity in Northwestern China). qRT-PCR demonstrated the miRNA expression in the invasion and cytotoxicity cell models. miR‑652-5p and miR‑21‑5p exhibited a consistent expression level in the microarray and cell models. Bioinformatics revealed that the potential targets of PLD1, MSH2, STC1, and DSG1 might be involved in ESCC invasion and proliferation. Cell models with bioinformatics approaches may help distinguish functional genes. miR‑652-5p, miR‑21‑5p, and their potential target genes may participate in ESCC development and metastasis.

PIK3CA promotes proliferation and motility but is unassociated with lymph node metastasis or prognosis in esophageal squamous cell carcinoma

The PIK3CA mutation has been extensively reported in the setting of cancers; however, the clinicopathological significance of PIK3CA expression has rarely been discussed in esophageal squamous cell carcinoma. In the present study, to confirm the significance of PIK3CA expression in association with metastasis and prognosis, which has been somewhat controversial in esophageal squamous cell carcinoma (ESCC), the relationship between clinicopathological features of ESCC and PIK3CA expression was analyzed using immunohistochemistry with a tissue microarray. Meanwhile, as additional verification and an ethnic control, another independent small cohort of Kazakh ESCC were analyzed by immunohistochemistry. To investigate the pilot role of PIK3CA in ESCC cells, ESCC cell lines ECa109 and EC9706 were transiently transfected with specific siRNA against PIK3CA. The silencing effect was detected by Western blot. Cell proliferation was examined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay; apoptosis and the cell cycles were analyzed by flow cytometry. Furthermore, the migratory and invasive ability were evaluated by wound healing and transwell invasion assay, respectively. Expression of PIK3CA was significantly higher in ESCC than in paired normal controls and was ethnicity independent; no statistically significant difference was observed between PIK3CA expression and sex, age, depth of invasion, tumor differentiation, lymph node metastasis, or prognosis. Proliferation, migration, and invasion were all markedly reduced after knockout of PIK3CA. Moreover, the cell cycle was arrested at the S phase, and the apoptosis rate was significantly increased, suggesting that PIK3CA plays a key role in promoting the proliferation and motility of ESCC cells.

Glutathione S-transferase M1 polymorphism and esophageal cancer risk: An updated meta-analysis based on 37 studies

AIM: To evaluate the relationship between glutathione S-transferase M1 (GSTM1) polymorphism and susceptibility to esophageal cancer (EC).

METHODS: A comprehensive search of the United States National Library of Medicine PubMed database and the Elsevier, Springer, and China National Knowledge Infrastructure databases for all relevant studies was conducted using combinations of the following terms: “glutathione S-transferase M1”, “GSTM1”, “polymorphism”, and “EC” (until November 1, 2014). The statistical analysis was performed using the SAS software (v.9.1.3; SAS Institute, Cary, NC, United States) and the Review Manager software (v.5.0; Oxford, England); crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between the GSTM1 null genotype and the risk of EC.

RESULTS: A total of 37 studies involving 2236 EC cases and 3243 controls were included in this meta-analysis. We observed that the GSTM1 null genotype was a significant risk factor for EC in most populations (OR = 1.33, 95%CI: 1.12-1.57, P_{heterogeneity} < 0.000001, and I² = 77.0%), particularly in the Asian population (OR = 1.53, 95%CI: 1.26-1.86, P_{heterogeneity} < 0.000001, and I² = 77.0%), but not in the Caucasian population (OR = 1.02, 95%CI: 0.87-1.19, P_{heterogeneity} = 0.97, and I² = 0%).

CONCLUSION: The GSTM1 null polymorphism may be associated with an increased risk for EC in Asian but not Caucasian populations.

Association between microRNA-196a2 rs11614913, microRNA-146a rs2910164, and microRNA-423 rs6505162 polymorphisms and esophageal cancer risk: A meta-analysis

Many observational studies have found that microRNA-196a2 rs11614913, microRNA-146a rs2910164, and microRNA-423 rs6505162 are associated with esophageal cancer risk. However, the results were mixed and inconsistent among these studies. We conducted a meta-analysis to assess the relationship between the polymorphisms of three microRNAs and esophageal cancer susceptibility. We systematically searched the PubMed and EMBASE databases to screen relevant studies. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to compute the risk of esophageal cancer. Because of the differences in ethnicities, sources of controls, and genotyping methods, the meta-analysis was conducted using a random-effect model regardless of heterogeneity. To further explore potential heterogeneity, we performed subgroup and sensitivity analyses, and publication bias was also evaluated. A total of 6 case-control studies on microRNA-196a2 rs11614913, 4 studies on microRNA-146a rs2910164, and 4 studies on microRNA-423 rs6505162 were considered eligible in the meta-analysis. No statistical association was found between microRNA-196a2 rs11614913, microRNA-146a rs2910164, and microRNA-423 rs6505162 polymorphisms and esophageal cancer susceptibility in any genetic model. Subgroup and sensitivity analyses showed similar results. In summary, based on the currently limited proof, no association exists between microRNA-196a2 rs11614913, microRNA-146a rs2910164, and microRNA-423 rs6505162 polymorphism and esophageal cancer risk. However, the result should be cautiously interpreted because of the heterogeneity among studies. Large, high quality clinical trials are required to verify our findings.

MicroRNA-21 promotes cell growth and migration by targeting programmed cell death 4 gene in Kazakh's esophageal squamous cell carcinoma

Esophageal cancer (EC) is the eighth most common cancer worldwide and the sixth most common cause of cancer death. There are two main types of EC--squamous cell carcinoma (ESCC) and adenocarcinoma (EAC). Although some advances in the exploration of its possible etiological mechanism were made recently including behaviors and environmental risk factors as well as gene alterations, the molecular mechanism underlying ESCC carcinogenesis and progression remains poorly understood. It has been reported that miR-21 was upregulated in most malignant cancers, the proposed mechanism of which was through suppressing expression of programmed cell death 4 (PDCD4). In present study, it is firstly reported that miR-21 was upregulated in Kazakh's ESCC and that miR-21 played a negative role in regulating PDCD4 using in situ hybridization (ISH) and luciferase reporter approach. Morever, in model of ESCC xenografted nude mice, miR-21 maybe used as an effective target in the treatment. The present results demonstrated that miR-21 may be a potential therapeutic target in management of ESCC.

Prognosis-related microRNAs in esophageal cancer

INTRODUCTION

Despite improvements in detection, surgical resection and adjuvant therapy, the prognosis of esophageal cancer (EC) patients is dismal. A number of microRNAs (miRNAs) are related with the prognosis of EC.

AREAS COVERED

This review summarises the recent advances in prognosis-related miRNAs in EC and also analyses the molecular functions that they provide. This study further envisages future developments in the potential clinical applications of these miRNAs.

EXPERT OPINION

Altered miRNA expression of cancer tissues is useful for predicting the prognosis of EC patients. Individual circulating miRNAs have the potential to be used as novel biomarkers. Continued basic studies are warranted to gain more mechanistic insights into the functional effect of prognosis-related miRNAs on EC. More clinical trials should be performed to promote the clinical use of prognosis-related miRNAs.

Chemotherapeutic and targeted strategies for locally advanced and metastatic esophageal cancer

INTRODUCTION

: Esophageal cancer represents a major health care problem worldwide and its prevalence is rapidly increasing. A key challenge in the treatment of both locally advanced and metastatic disease is to improve our understanding of the underlying molecular biology. Herein we discuss the most active chemotherapies and targeted agents for esophageal cancer, and explore potential differences in the disease between Eastern and Western countries.

METHODS

: We reviewed the literature for trials involving chemotherapy and targeted agents in locally advanced and metastatic disease in the last 20 years. The search was supplemented by a review of the abstracts presented at the annual American Society of Clinical Oncology meetings from 1992 to 2012.

RESULTS

: Neoadjuvant chemo-radiation followed by surgery remains standard of care for operable disease. Definitive chemo-radiation can be considered for locally advanced squamous cell tumors. Platinum-based combination chemotherapy is preferable in the first-line metastatic setting. Recently, HER2, EGFR, and VEGF-targeted agents have been extensively investigated as single agents or in combination with chemotherapy. Several new targets are being explored.

CONCLUSIONS

: There have been incremental improvements in our understanding of the molecular biology of esophageal cancer, and ethnic differences between Asian and Western populations are becoming apparent. Next-generation sequencing has failed to demonstrate significant oncogenic drivers; however, the addition of trastuzumab to chemotherapy for HER2-amplified tumors has been validated in the metastatic setting and is undergoing investigation in operable disease. Epigenetic therapeutics may provide additional benefit in future years for this difficult-to-treat disease.

The NQO1 polymorphism C609T (Pro187Ser) and cancer susceptibility: a comprehensive meta-analysis

Background:

Evidence is increasingly emerging about multiple roles for the NAD(P)H quinone oxidoreductase 1 enzyme in cancer. The C609T (rs1800566, Pro187Ser) null polymorphism of the NQO1 gene contributes significantly to the variation in enzymatic activity across different populations. NQO1 C609T polymorphism was thoroughly investigated with respect to cancer susceptibility. The results were inconsistent partly due to low sample sizes. The aim of the present work was to perform a meta-analysis to assess association for all common cancer sites separately and in combination.

Methods:

Our meta-analysis involved 92 studies including 21 178 cases and 25 157 controls. Statistical analysis involved individual cancer sites and the combined cancer risk. Association was tested under different genetic models.

Results:

We found a statistically significant association between the variant T allele and overall cancer risk in the worldwide population (for the TT vs CC model, OR=1.18 (1.07–1.31), P=0.002, I²=36%). Stratified analysis revealed that this association was largely attributed to the Caucasian ethnicity (for the TT vs CC model, OR=1.28 (1.12–1.46), P=0.0002, I²=1%). Stratification by tumour site showed significant association for bladder cancer in the worldwide population (for the TT vs CC model, OR=1.70 (1.17–2.46), P=0.005, I²=0%), and in the Asian population (for the TT vs CC model, 1.48 (1.14–1.93), P=0.003, I²=16%). Positive association was also found for gastric cancer in the worldwide population under the dominant model (OR=1.34 (1.09–1.65), P=0.006, I²=15%).

Conclusion:

Our results indicate that the C609T polymorphism of the NQO1 gene is an important genetic risk factor in cancer.

Glutathione S-transferase M1 null genotype contributes to increased risk of esophageal carcinoma in Chinese population

Glutathione S-transferases (GSTs) play important roles in the detoxification of electrophilic carcinogens, and GSTM1 null genotype is associated with the dysfunction of GSTs. Previous studies investigating the association between GSTM1 null genotype and risk of esophageal carcinoma in Chinese provided inconsistent findings. To provide a more precise estimation on the association between GSTM1 null genotype and risk of esophageal carcinoma in Chinese population, a meta-analysis was performed. Eligible studies were searched in PubMed, Embase, and China National Knowledge Infrastructure databases. Odds ratio (OR) with the corresponding 95 % confidence interval (95 %CI) was used to assess the association. A total of 18 case-control studies involving 1,947 cases and 3,506 controls were finally included in the meta-analysis. Meta-analysis of those 18 studies showed that GSTM1 null genotype was associated with an increased risk of esophageal carcinoma in Chinese (random effect model OR = 1.49, 95 %CI = 1.11-2.00, P = 0.008). The findings from cumulative meta-analysis showed that the association was more obvious as the data increased by publication year. There was no risk of publication bias in the meta-analysis. Therefore, the findings from our meta-analysis provide a strong evidence for the association between GSTM1 null genotype and risk of esophageal carcinoma in Chinese population, and GSTM1 null genotype contributes to increased risk of esophageal carcinoma in Chinese.

Roles of phosphorylated JNK in esophageal squamous cell carcinomas of Kazakh ethnic

The c-Jun NH2 -terminal kinase (JNK) signal pathway has been implicated in the growth, cellular proliferation, and apoptosis in many kinds of carcinomas. However, the role of JNK in the development of esophageal squamous cell carcinomas (ESCCs) is unknown. To investigate the role of JNK in ESCC, in vitro, esophageal cancer cell line Eca109 was pretreated using SP600125, JNK specific inhibitor, then was subjected to MTT assay to examine cellular proliferation, flow cytometric analysis to detect apoptosis and cell cycle, and wound healing assay to evaluate cell migration. Meanwhile, the mRNA and protein expression of JNK in Eca109 cells pretreated with SP600125 were examined by real-time quantitative reverse transcription PCR (qRT-PCR) and Western blotting, respectively. In vivo, 12 paired of fresh ESCC and normal adjacent tissues (NAT) from Kazakh patients were used to validate the expression of JNK by qRT-PCR and Western blotting. Furthermore, to reconfirm the expression trend of activation JNK (p-JNK), enlarged 72 paired of Kazakh's ESCC and NAT were subjected to immunohistochemistry. Our results showed that the suppression of p-JNK could lead to apoptosis and reduce proliferation in Eca109 cells. However, there was an elevated expression of p-JNK protein in NAT compared with ESCC tissues, and there was significant difference between p-JNK expression and pathological differentiation (P < 0.05) in Kazakh populations. Together, all the data we obtained in the present study indicated that the p-JNK MAPK pathway was involved in pathogenesis of Kazakh's ESCC, and played a different roles in carcinogenesis and development of Kazakh's ESCC.

Interaction between alcohol consumption and CYP 2C19 gene polymorphism in relation to oesophageal squamous cell carcinoma

OBJECTIVES

The purpose of this study is to explore the relationship between the interactions of CYP2C19 gene polymorphisms and several environmental factors and oesophageal squamous cell carcinoma (OSCC).

METHODS

In a case-control study of OSCC patients (n = 350) and healthy controls (n = 350), we investigated the roles of polymorphism in the CYP2C19 gene by the use of polymerase chain reaction--restriction fragment length polymorphism (PCR - RFLP) analysis.

RESULTS

The CYP2C19(*)3 AG+AA genotype was significantly more prevalent in OSCC patients (10.0% versus 3.43%; P<0.01). Multiple logistic regression analysis showed drinking (OR: 5.603, 95% CI: 3.431-11.112; P = 0.005) and smoking (OR: 4.341, 95% CI: 3.425-10.241; P = 0.001) was the independent risk factor of OSCC respectively, and there were significant interaction between CYP2C19(*)3 and drinking (OR: 8.747, 95% CI: 6.321-18.122; P = 0.009).

CONCLUSIONS

The CYP2C19(*)3 polymorphism and OSCC were synergistically and significantly associated in Chinese Han patients.