A review of the current understanding and clinical utility of miRNAs in esophageal cancer

JunD-miR494-CUL3 axis promotes radioresistance and metastasis by facilitating EMT and restraining PD-L1 degradation in esophageal squamous cell carcinoma

Therapy resistance and metastatic progression jointly determine the fatal outcome of cancer, therefore, elucidating their crosstalk may provide new opportunities to improve therapeutic efficacy and prevent recurrence and metastasis in esophageal squamous cell carcinoma (ESCC). Here, we have established radioresistant ESCC cells with the remarkable metastatic capacity, and identified miR-494-3p (miR494) as a radioresistant activator. Mechanistically, we demonstrated that cullin 3 (CUL3) is a direct target of miR494, which is transcriptionally regulated by JunD, and highlighted that JunD-miR494-CUL3 axis promotes radioresistance and metastasis by facilitating epithelial-mesenchymal transition (EMT) and restraining programmed cell death 1 ligand 1 (PD-L1) degradation. In clinical specimens, miR494 is significantly up-regulated and positively associated with T stage and lymph node metastasis in ESCC tissues and serum. Notably, patients with higher serum miR494 expression have poor prognosis, and patients with higher CUL3 expression have more conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs), less cancer-associated fibroblasts (CAF2/4), and tumor endothelial cells (TEC2/3) infiltration than patients with lower CUL3 expression, suggesting that CUL3 may be involved in tumor microenvironment (TME). Overall, miR494 may serve as a potential prognostic predictor and therapeutic target, providing a promising strategy for ESCC treatment.

Next Generation Sequencing for Potential Regulated Genes and Micro-RNAs of Early Growth Response-1 in the Esophageal Squamous Cell Carcinoma

Esophageal cancer has a poor prognosis due to its aggressiveness and low survival rate. In Ease Asia, esophageal squamous cell carcinoma (ESCC) outnumbers esophageal adenocarcinoma (EAC). The ESCC patients still have high mortality despite modern surgical resection and neoadjuvant treatment. Determining patient and outcome prognostic factors is critical in ESCC treatment. In esophageal cancer, early growth response-1 (Egr-1) is a tumor suppressor gene, but the mechanism and associated genes are unknown. The study utilizes RNA interference method, the platform of Next Generation Sequencing (NGS) and bioinformatics analysis to investigate the influences after the Egr-1 gene slicing on the ESCC cells. The heat maps of differentially expressed mRNA and microRNAs were analyzed using the algorithm, Burrows-Wheller Aligner. The study showed that the expression of 51 mRNA and 26 microRNAs have significant changes in ESCC cells after Egr-1 knockdown. The KEGG enrichment analysis linked Egr-1-regulated genes and microRNAs. Egr-1 interactions with these genes and microRNAs may be important in tumor progression. In conclusions, this study provided the transcriptome patterns and relating pathway analysis for Egr-1 knockdown in ESCC cells. The mRNA and microRNAs altered by Egr-1 gene silencing might provide key information in the treatment of ESCC.

Exploiting the Molecular Basis of Oesophageal Cancer for Targeted Therapies and Biomarkers for Drug Response: Guiding Clinical Decision-Making

Worldwide, oesophageal cancer is the sixth leading cause of deaths related to cancer and represents a major health concern. Sub-Saharan Africa is one of the regions of the world with the highest incidence and mortality rates for oesophageal cancer and most of the cases of oesophageal cancer in this region are oesophageal squamous cell carcinoma (OSCC). The development and progression of OSCC is characterized by genomic changes which can be utilized as diagnostic or prognostic markers. These include changes in the expression of various genes involved in signaling pathways that regulate pathways that regulate processes that are related to the hallmarks of cancer, changes in the tumor mutational burden, changes in alternate splicing and changes in the expression of non-coding RNAs such as miRNA. These genomic changes give rise to characteristic profiles of altered proteins, transcriptomes, spliceosomes and genomes which can be used in clinical applications to monitor specific disease related parameters. Some of these profiles are characteristic of more aggressive forms of cancer or are indicative of treatment resistance or tumors that will be difficult to treat or require more specialized specific treatments. In Sub-Saharan region of Africa there is a high incidence of viral infections such as HPV and HIV, which are both risk factors for OSCC. The genomic changes that occur due to these infections can serve as diagnostic markers for OSCC related to viral infection. Clinically this is an important distinction as it influences treatment as well as disease progression and treatment monitoring practices. This underlines the importance of the characterization of the molecular landscape of OSCC in order to provide the best treatment, care, diagnosis and screening options for the management of OSCC.

Clinical significance of FBXW7 loss of function in human cancers

FBXW7 (F-Box and WD Repeat Domain Containing 7) (also referred to as FBW7 or hCDC4) is a component of the Skp1-Cdc53 / Cullin-F-box-protein complex (SCF/β-TrCP). As a member of the F-box protein family, FBXW7 serves a role in phosphorylation-dependent ubiquitination and proteasome degradation of oncoproteins that play critical role(s) in oncogenesis. FBXW7 affects many regulatory functions involved in cell survival, cell proliferation, tumor invasion, DNA damage repair, genomic instability and telomere biology. This thorough review of current literature details how FBXW7 expression and functions are regulated through multiple mechanisms and how that ultimately drives tumorigenesis in a wide array of cell types. The clinical significance of FBXW7 is highlighted by the fact that FBXW7 is frequently inactivated in human lung, colon, and hematopoietic cancers. The loss of FBXW7 can serve as an independent prognostic marker and is significantly correlated with the resistance of tumor cells to chemotherapeutic agents and poorer disease outcomes. Recent evidence shows that genetic mutation of FBXW7 differentially affects the degradation of specific cellular targets resulting in a distinct and specific pattern of activation/inactivation of cell signaling pathways. The clinical significance of FBXW7 mutations in the context of tumor development, progression, and resistance to therapies as well as opportunities for targeted therapies is discussed.

Prediction of potential miRNA-disease associations based on stacked autoencoder

In recent years, increasing biological experiments and scientific studies have demonstrated that microRNA (miRNA) plays an important role in the development of human complex diseases. Therefore, discovering miRNA-disease associations can contribute to accurate diagnosis and effective treatment of diseases. Identifying miRNA-disease associations through computational methods based on biological data has been proven to be low-cost and high-efficiency. In this study, we proposed a computational model named Stacked Autoencoder for potential MiRNA-Disease Association prediction (SAEMDA). In SAEMDA, all the miRNA-disease samples were used to pretrain a Stacked Autoencoder (SAE) in an unsupervised manner. Then, the positive samples and the same number of selected negative samples were utilized to fine-tune SAE in a supervised manner after adding an output layer with softmax classifier to the SAE. SAEMDA can make full use of the feature information of all unlabeled miRNA-disease pairs. Therefore, SAEMDA is suitable for our dataset containing small labeled samples and large unlabeled samples. As a result, SAEMDA achieved AUCs of 0.9210 and 0.8343 in global and local leave-one-out cross validation. Besides, SAEMDA obtained an average AUC and standard deviation of 0.9102 ± /-0.0029 in 100 times of 5-fold cross validation. These results were better than those of previous models. Moreover, we carried out three case studies to further demonstrate the predictive accuracy of SAEMDA. As a result, 82% (breast neoplasms), 100% (lung neoplasms) and 90% (esophageal neoplasms) of the top 50 predicted miRNAs were verified by databases. Thus, SAEMDA could be a useful and reliable model to predict potential miRNA-disease associations.

circFIG 4 drives the carcinogenesis and metastasis of esophagus cancer via the miR-493-5p/E2F3 axis

Background

Esophageal cancer (EC) is a highly malignant tumor of the digestive tract. Circular RNAs (circRNAs) have been verified to play a regulatory role in the occurrence and progression of different cancers, including EC. This research aimed to investigate the role and molecular mechanism of circFIG 4 in EC progression.

Methods

The analyses of circFIG 4, miR‐493‐5p, and neuro‐oncological ventral antigen 2 levels were administrated by quantitative real‐time polymerase chain reaction. The characteristics of circFIG 4 were determined by Ribonuclease R assay and Actinomycin D assay. Cell proliferation was assessed via colony formation assay and 5‐ethynyl‐2′‐deoxyuridine incorporation assay. Cell cycle distribution and apoptosis were evaluated by flow cytometry. Western blot was performed to assess protein expression. The targeted interaction among circFIG 4, miR‐493‐5p, and E2F transcription factor 3 (E2F3) were validated using dual‐luciferase reporter or RNA immunoprecipitation assays.

Results

circFIG 4 was overtly upregulated in EC and was relatively stable in EC cells. circFIG 4 knockdown impeded proliferation, migration, and invasion and expedited apoptosis in EC cells. circFIG 4 served as a miR‐493‐5p sponge to act in the development of EC. Furthermore, circFIG 4 modulated EC progression via targeting miR‐493‐5p and miR‐493‐5p suppressed EC progression via targeting E2F3. circFIG 4 modulated E2F3 expression through acting as a sponge of miR‐493‐5p. Moreover, circFIG 4 knockdown inhibited EC tumorigenesis by targeting miR‐493‐5p/E2F3 axis tumor growth in vivo.

Conclusion

circFIG 4 silence mitigated EC malignant progression at least partly by mediating the miR‐493‐5p/E2F3 pathway, highlighting new biomarkers and therapeutic targets for EC treatment.

Circulating MicroRNAs in Relation to Esophageal Adenocarcinoma Diagnosis and Survival

BACKGROUND AND AIMS

Tissue miRNA can discriminate between esophageal adenocarcinoma (EA) and normal epithelium. However, no studies have examined a comprehensive panel of circulating miRNAs in relation to EA diagnosis and survival.

METHODS

We used all 62 EA cases from the US Multi-Center case-control study with available serum matched 1:1 to controls. Cases were followed for vital status. MiRNAs (n = 2064) were assessed using the HTG EdgeSeq miRNA Whole Transcriptome Assay. Differential expression analysis of miRNAs in relation to case-control status was conducted. In cases, Cox regression models were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. P values were adjusted using the Benjamini-Hochberg (BH) procedure for false discovery rate control. Predictive performance was assessed using cross-validation.

RESULTS

Sixty-eight distinct miRNAs were significantly upregulated between cases and controls (e.g., miR-1255b-2-3p fold change = 1.74, BH-adjusted P = 0.01). Assessing the predictive performance of these significantly upregulated miRNAs yielded 60% sensitivity, 65% specificity, and 0.62 AUC. miR-4253 and miR-1238-5p were associated with risk of mortality after EA diagnosis (HR = 4.85, 95% CI: 2.30-10.23, BH-adjusted P = 0.04 and HR = 3.81, 95% CI: 2.02-7.19, BH-adjusted P = 0.04, respectively).

CONCLUSIONS

While they require replication, these findings suggest that circulating miRNAs may be associated with EA diagnosis and survival.

MicroRNA -196b is related to the overall survival of patients with esophageal squamous cell carcinoma and facilitates tumor progression by regulating SOCS2 (Suppressor Of Cytokine Signaling 2)

Esophageal squamous cell carcinoma (ESCC) is common cancer in China. At the same time, microRNA-196b (miR-196b) has different promotion/inhibition effects in different cancers. The study aims to reveal the role of miR-196b in ESCC and explore its prognostic value. The expression of miR-196b in ESCC samples and cell lines was detected to explore the expression pattern of miR-196b in ESCC. Kaplan-Meier method was conducted for survival rate and Multivariate Cox analysis was used to explore the clinical significance of miR-196b in ESCC. The Cell Counting Kit-8 (CCK-8) assay, transwell migration and invasion tests were used to determine the biological function of miR-196b in ESCC. The relationship of miR-196b and SOCS2 in ESCC was detected by luciferase activity assay and RIP assay. Both in ESCC tissues and cell lines, miR-196b expression was up-regulated. miR-196b expression is related to TNM stage and lymph node metastasis. Combining with the results of Multivariate Cox regression analysis, miR-196b may be a potential independent prognostic marker for ESCC patients. The results of the functional analysis showed that miR-196b inhibitor can reduce cell proliferation, migration and invasion in ESCC cells. Besides, the suppressor of cytokine signaling 2 (SOCS2) is the target of miR-196b in ESCC. miR-196b may exist as a tumor-promoting factor in ESCC and enhance the proliferation abilities, migration capacities, and invasion potential of ESCC cells by targeting SOCS2. miR-196b and SOCS2 have a close negative correlation in ESCC, which may be used as a clinically poor prognostic biomarker and therapeutic target for ESCC.

LncRNA RP11-465B22.8 triggers esophageal cancer progression by targeting miR-765/KLK4 axis

LncRNAs play an important role in tumorigenesis and progression; however, the function and mechanisms of lncRNAs in esophageal cancer (EC) remain largely unclear. In this study, we screened the differentially expressed lncRNAs in EC by using RNA-seq and one of the most upregulated lncRNAs, lncRNA RP11-465B22.8, was further characterized. LncRNA RP11-465B22.8 was upregulated in EC tissues and high lncRNA RP11-465B22.8 expression was associated with poor survival of EC patients. Ectopic expression of lncRNA RP11-465B22.8 enhanced the proliferation, migration, and invasion of EC cells, whereas knockdown of lncRNA RP11-465B22.8 led to the opposite effects. Mechanistically, lncRNA RP11-465B22.8 sponged miR-765 to increase the expression of KLK4. Moreover, LncRNA RP11-465B22.8 could be delivered from EC cells to macrophages via exosomes and subsequently induced M2 macrophage-induced cell migration and invasion. Our findings revealed a novel lncRNA RP11-465B22.8/miR-765/KLK4 pathway in EC and indicated that lncRNA RP11-465B22.8 might be a potential target for EC therapy.

Quercetin Antagonizes Esophagus Cancer by Modulating miR-1-3p/TAGLN2 Pathway-Dependent Growth and Metastasis

The progression of esophagus cancer (EC) is associated with the alterative expressions of multiple microRNAs (miRs). MiR-1-3p is reported to inhibit the development of EC by targeting TAGLN2. Quercetin (Que) is a natural compound capable of antagonizing esophagus carcinoma (EC). In the current study, the role of miR-1-3p/TAGLN2 axis in the anti-EC function of Que was explored. Human EC cell lines KYSE-510 and TE-7 were treated with Que. Then the effects of Que on the growth and metastasis of EC cells, and on the activity of miR-1-3p/TAGLN2 axis were detected. The interaction between Que and miR-1-3p axis was further assessed by inhibiting miR-1-3p level in EC cells. The results showed that the treatment of Que impaired the growth and induced cell apoptosis in EC cells. The invasive ability of EC cells was also suppressed by Que. At molecular level, the expression of miR-1-3p was induced, while the expression of TAGLN2 was suppressed by Que. Moreover, the anti-EC effects of Que were blocked by miR-1-3p inhibition, which was represented by the restored growth and invasion of EC cells. Collectively, the current study demonstrated that Que exerted inhibitory effects on EC cells by inducing miR-1-3p.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1972125.

Roles of microRNAs in tumorigenesis and metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the major subtype of esophageal cancer that is prevalent in Eastern Asia. Despite recent advances in therapy, the outcome of ESCC patients is still dismal. MicroRNAs (miRNAs) are non-coding RNAs which can negatively modulate gene expression at the post-transcriptional level. The involvement and roles of miRNAs have become one of the hot topics of cancer research in recent years. In ESCC, genetic variations within miRNA coding genes were found to have distinct epidemiological significance in different populations. Dysregulated expression of several miRNAs was reported to be associated with therapeutic response. Functionally, miRNAs can act either in an oncogenic or a tumor-suppressive manner during tumorigenesis of ESCC by interrupting signaling pathways associated with cell proliferation, metabolism, cancer stemness, and resistance to chemo- or radiotherapy. Moreover, miRNAs modulate metastasis of ESCC by targeting genes that regulate cytoskeleton dynamics, extracellular matrix remodeling, epithelial-mesenchymal transition, and tumor microenvironment. Most importantly, mounting evidence suggests that inhibiting oncogenic miRNAs or restoring the loss of tumor-suppressive miRNAs has therapeutic potential in the treatment of ESCC. Here, we review and discuss recent studies on the significance, biological functions, and therapeutic potential of miRNAs in tumorigenesis and metastasis of ESCC.

Dual inhibition of cMET and EGFR by microRNA-338-5p suppresses metastasis of esophageal squamous cell carcinoma

MicroRNAs, as a group of post-transcriptional regulators, regulate multiple pathological processes including metastasis during tumor development. Here, we demonstrated the metastasis-suppressive function of microRNA (miR)-338-5p in esophageal squamous cell carcinoma (ESCC). Overexpression of miR-338-5p had inhibitory effect on invasive ability of ESCC cells and extracellular matrix degradation, whereas silencing miR-338-5p had opposite effects. Mechanistically, miR-338-5p directly targeted the 3' untranslated regions of hepatocellular growth factor receptor cMet (cMET) and epidermal growth factor receptor (EGFR). As a result, miR-338-5p inhibited the downstream signaling cascades of cMET and EGFR and repressed cMET- and EGFR-mediated ESCC cell invasion. Re-expression of cMET or EGFR in miR-338-5p overexpressing ESCC cells was sufficient to derepress ESCC cell invasion both in vitro and in vivo. We further showed that such manipulation downregulated the expression and secretion of matrix metalloproteinases 2 and 9, which resulted in impaired extracellular matrix degradation and cell invasion. Most importantly, systemic delivery of miR-338-5p mimic significantly inhibited metastasis of ESCC cells in nude mice. Taken together, our results uncovered a previously unknown mechanism through which miR-338-5p suppresses ESCC invasion and metastasis by regulating cMET/EGFR-matrix metalloproteinase 2/9 axis and highlighted the potential significance of miR-338-5p-based therapy in treating patients with metastatic ESCC.

Screening of tumor grade-related mRNAs and lncRNAs for Esophagus Squamous Cell Carcinoma

Background

The goal of our study was to screen tumor grade‐related lncRNAs and mRNAs to reveal the underlying molecular mechanism of esophagus squamous cell carcinoma (ESCC).

Methods

The lncRNA and mRNA sequencing data were obtained from The Cancer Genome Atlas (TCGA). Tumor grade correlation analysis of lncRNAs and mRNAs was executed, followed by the functional enrichment analysis of all tumor grade‐related mRNAs. The differentially expression mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs) were obtained. PPI network and DEmRNA‐DElncRNA interaction analysis were constructed. The functional annotation of the DEmRNAs co‐expressed with DElncRNAs was performed. The expression levels of the candidate genes were validated using qRT‐PCR.

Results

A total of 1864 tumor grade‐related mRNAs (846 positively related and 1018 negatively related) and 552 tumor grade‐related lncRNAs (331 positively related and 221 negatively related) were obtained. The top 10 significantly grade‐related mRNAs and lncRNAs included CA12, FABP4, DECR1, BAIAP2, IL1RAPL2, PPARD, LAD1, TSPAN10, LDOC1, ZNF853, RP11‐25G10.2, RP11‐557H15.3, RP11‐521D12.5, CHKB‐AS1, RP11‐219B4.3, CH17‐335B8.4, RP11‐99 J16‐A.2, CTB‐111H14.1, ADNP‐AS1, and JHDM1D‐AS1. SFN, IL1RAPL2, and RP11‐25G10.2 were overlapped from grade 1, grade 2, and grade 3. PPI network showed that top 10 proteins with higher degrees, including GNAI1, RAP2B, GNAZ, SHH, ADCY1, PRKAR2B, SH3GL1, GNA15, and ARRB1. A DElncRNAs‐nearby DEmRNAs network was constructed to obtain hub lncRNAs including ADAMTS9‐AS2, RP11‐210 M15.2, RP11‐13 K12.1, ZBED3‐AS1, and RP11‐25G10.2. Except for RP11‐25G10.2, ADAMTS9‐AS1, ZBED3‐AS1, SFN, ATP1A2, and GNA15 were consistent with our TCGA analysis.

Conclusions

Alterations of DEmRNAs and DElncRNAs may provide key insights into the molecular mechanisms of ESCC.

High expression of spermatogenesis associated serine rich 2 promotes tumorigenicity in esophageal squamous cell carcinoma cells and is associated with poor patient prognosis

Spermatogenesis associated serine rich 2 (SPATS2), recognized as a cytoplasmic RNA-binding protein, is implicated in the tumorgenicity of several cancers. However, the potential role of SPATS2 in esophageal squamous cell carcinoma (ESCC) is yet to be elucidated. The present study aimed to explore the functional implication of SPATS2 in ESCC. The ESCC cell lines Eca109 and KYSE-150 were used to conduct loss-of-function experiments. The expression patterns of SPATS2 in patients with ESCC were obtained from Oncomine, The Cancer Genome Atlas and Genotype-Tissue Expression databases. Reverse transcription-quantitative PCR and western blot analysis were applied to determine the expression levels of SPATS2 in ESCC cells. The proliferation of ESCC cells was measured via cell proliferation and colony-formation assays. Subsequently, the migration and invasion capacities of ESCC cells were observed using Transwell assays. Finally, the expression levels of P53, cyclin E, matrix metalloproteinase (MMP)-9 and neuronal-cadherin were determined via western blot analysis. SPATS2 was expressed at higher levels in ESCC tissues compared with the controls, and high expression of SPATS2 was associated with poor prognosis. ESCC cell line proliferation, migration and invasion abilities were suppressed after silencing SPATS2. Moreover, following knockdown of SPATS2, the proteins cyclin E, MMP-9 and N-cadherin were expressed at markedly decreased levels, while P53 expression was increased. In summary, the results of the present study suggest that SPATS2 promotes ESCC development and progression, providing potential insights into future ESCC targeted treatment.

The predictive value of microRNAs for pathological response after neoadjuvant treatment in esophageal squamous cell carcinoma: a systematic review

Neoadjuvant treatment followed by esophagectomy has been the standard strategy for resectable locally advanced esophageal squamous cell carcinoma (ESCC). Pathological response after neoadjuvant treatment is of vital importance in the determination of long-term survival. Due to the involvement of microRNAs (miRNAs) in ESCC, some studies have proposed miRNA models to predict the pathological response. We aimed to summarize current studies on the predictive value of the miRNA models. We searched the relevant studies on PubMed, Web of Science and Cochrane Library up to February 14, 2020, using the following search term: (esophageal OR esophagus OR oesophageal OR oesophagus) AND (miR OR miRNA OR microRNA) AND (neoadjuvant OR preoperative OR induction). The initial search retrieved 206 studies. We briefly summarized the involvement of miRNAs in the origin, development and chemo- and radioresistance in ESCC. Then, 9 studies were enrolled in the systematic review. A great heterogeneity was observed across these studies. Of the 6 studies with diagnostic tests, the area under curve varied a lot. Although much evidence demonstrated the correlation between miRNAs and pathological response after in ESCC, the current studies has not established any promising models. A well-designed prospective study is essential to investigate the potential predictive models for pathological response after neoadjuvant treatment in ESCC.

Upregulation of PEDF Predicts a Poor Prognosis and Promotes Esophageal Squamous Cell Carcinoma Progression by Modulating the MAPK/ERK Signaling Pathway

Invasion and metastasis represent the primary causes of therapeutic failure in patients diagnosed with esophageal squamous cell carcinoma (ESCC). The lack of effective treatment strategies for metastatic ESCC is the major cause of the low survival rate. Therefore, it is crucial to understand the molecular mechanisms underlying ESCC metastasis and identify potential biomarkers for targeted therapy. Herein, we reported that PEDF is significantly correlated with tumor cell invasion and metastasis in ESCC. The high expression of PEDF is an independent unfavorable prognostic factor for ESCC patients’ overall survival (OS). We successfully developed and verified a nomogram to predict the preoperative OS of ESCC patients, and the actual and nomogram-predicted 1-, 3-, and 5-year survival rates had good consistency. The receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) values for 1-, 3- and 5- survival were 0.764, 0.871, and 0.91, respectively. Overexpression of PEDF significantly promoted the migration and invasion of ESCC cells in vitro, while silencing PEDF yielded the opposite effects. Elevated levels of PEDF altered the expression of proteins involved in epithelial–mesenchymal transition (EMT), as indicated by the upregulation of N-cadherin and the downregulation of α-catenin and E-cadherin in ESCC cells. Mechanistically, PEDF promoted tumor cell motility and EMT by activating the MAPK/ERK signaling pathway. In conclusion, our results reveal that PEDF is involved in ESCC metastasis and could act as a prognostic factor for ESCC. Our research provides a fresh perspective into the mechanism of ESCC metastasis.

Loss of FBP1 promotes proliferation, migration, and invasion by regulating fatty acid metabolism in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in China. Recent studies have shown fatty acid metabolism is involved in the progression of various cancers through regulating the function of various types of cells. However, the relationship between fatty acid metabolism and tumorigenesis of ESCC remains unclear. Here, in this study, the expression of FBP1 was dramatically decreased in ESCC tissues compared with the adjacent non-ESCC tissues. The cell proliferation, migration, invasion and fatty acid metabolism were evaluated in ESCC cells using transfection of shFBP1 vectors. We found loss of FBP1 promoted ESCC cell proliferation, migration and invasion, which correlated with the activated fatty acid metabolism in vitro. Moreover, the content of phospholipids, triglycerides, neutral lipids and the protein expression levels of fatty acid metabolism related FASN, ACC1 and SREBP1C proteins were significantly increased following down-regulation of FBP1. Furthermore, FBP1 was found to be directly targeted by miR-18b-5p in ESCC cells. In addition, miR-18b-5p inhibitor treatment obviously reversed the increased fatty acid metabolism induced by loss of FBP1 in ESCC cells. These findings explored a detailed molecular mechanism of tumorigenesis and progression of ESCC and might provide a potential novel method to treat ESCC in clinic.

SOX2-Upregulated microRNA-30e Promotes the Progression of Esophageal Cancer via Regulation of the USP4/SMAD4/CK2 Axis

Esophageal cancer (EC) is a highly aggressive disease, and its progression involves a complex gene regulation network. Transcription factor SOX2 is amplified in various cancers including EC. A pathway involving SOX2 regulation of microRNAs (miRNAs) and their target genes has been previously revealed. This study aims to delineate the ability of SOX2 to influence the EC progression, with the involvement of miR-30e/USP4/SMAD4/CK2 axis. SOX2 expression was first examined in the clinical tissue samples from 30 EC patients. Effects of SOX2 on proliferation, migration, and invasion alongside tumorigenicity of transfected cells were examined by means of gain- and loss-of-function experiments. EC tissues and cells exhibited high expression of SOX2, miR-30e, and CK2 and poor expression of USP4 and SMAD4. Mechanistically, SOX2 was positively correlated with miR-30e and upregulated the expression of miR-30e. miR-30e specifically targeted USP4, which induced deubiquitination of SMAD4 and promoted its expression. Meanwhile, SMAD4 was enriched in the CK2 promoter region and thus inhibited its expression. SOX2 stimulated EC cell proliferative, invasive, and migratory capacities in vitro and tumor growth in vivo by regulating the miR-30e/USP4/SMAD4/CK2 axis. Collectively, our work reveals a novel SOX2-mediated regulatory network in EC that may be a viable target for EC treatment.

MicroRNA expression profiles in the esophagus of children with caustic stenosis: A pathway towards esophageal cancer?

BACKGROUND

Eighty percent of caustic ingestions occur in children and esophageal neoplasms may develop as a late complication of such injury. The identification of biomarkers is a promising strategy to improve early diagnosis of esophageal cancer or caustic lesions that are at an increased risk of progression.

STUDY DESIGN/AIMS

This study aimed at identifying global microRNA (miRNA) expression changes in esophageal mucosa from children with caustic stenosis. The study included 27 biopsy samples from 15 patients. Samples were divided into two groups, according to the time elapsed after injury (N = 15 in Group A, with less than five years of follow-up and N = 12 in Group B, with more than five years of follow-up). miRNA expression profiles were determined in each lesion, compared with normal esophageal tissues from control group. We used the TaqMan Human MicroRNA Arrays (Thermo Fisher) platform. Furthermore, bioinformatic algorithms were used to identify miRNA target genes and biological pathways including miRNAs and their target genes potentially associated with esophageal disease.

RESULTS

Thirteen miRNAs were significantly deregulated (9 over- and 4 underexpressed) in patients from Group A. In patients from Group B, two miRNAs were over- and two were underexpressed. Of note, miR-374 and miR-574 were deregulated in Group B patients and have been linked to esophageal tumorigenesis. We identified signal transduction and transcription factor networks with genes strongly related to development and progression of esophageal cancer.

CONCLUSION

miRNAs identified here contribute to a better understanding of pathways associated with malignant transformation from caustic stenosis to neoplastic lesions. This study may serve as a basis for validation of miRNAs, including miR-374 and miR-574, as potential biomarkers of early cancer detection.

Expression of miRNA in 5-FU resistant esophageal cancer

Fluoropyrimidine plus platinum (FP) are chemotherapeutic drugs that are most frequently used to treat esophageal squamous cell carcinoma (ESCC). However, drug resistance often occurs, and the mechanisms of resistance to 5-FU is yet to be determined. The role of micro (mi)RNAs has been well established in a variety of human cancers. The aim of the present study was to investigate the expression profile of ESCC, revealing the differential expression between ESCC and 5-FU resistant ESCC. The establishment of a 5-FU resistant (5-FUR) cell lines model provides a way of analyzing the expression of miRNAs in drug resistance. The miRNA expression indicated 50 miRNAs that were upregulated in TE10-5-FUR compared with TE10, while 119 miRNAs were downregulated. The TE11-5-FUR demonstrated 140 miRNAs were upregulated compared with TE11, which exhibited 12 downregulated miRNAs. Both cell lines share the 2 candidate upregulated miRNAs (miR-146a and miR-483-5p) and 5 downregulated miRNAs (miR-34a, miR-141, miR-200b, miR-200c and miR-205). Further studies are required to analyze and evaluate the function of the miRNAs.

Suppression of long non-coding RNA MALAT1 inhibits survival and metastasis of esophagus cancer cells by sponging miR-1-3p/CORO1C/TPM3 axis

Esophageal cancer (EC) is a malignancy causing lots of mortality worldwide. Long non-coding RNAs (lncRNAs) are involved in the progression of multiple cancer types. The present study aimed to explore the function and associated mechanisms of lncRNA metastasis-associated lung adenocarcinoma transcript1 (MALAT1) in EC development by focusing on its interaction with miR-1-3p. The levels of MALAT1 and miR-1-3p were investigated in clinical EC specimens. Then, the expression of MALAT1 was knocked down in EC cell lines, and the effects of MALAT1 inhibition on the viability, migration, and invasion, and miR-1-3p/Coronin-1C (CORO1C)/Tropomyosin3 (TPM3) axis in EC cells were detected. The interaction between MALAT1 and miR-1-3p in the progression of EC was further determined by suppressing the expression of miR-1-3p in MALAT1 inhibition cells. The results were further verified with EC xenograft mice model. MALAT1 level was downregulated, while miR-1-3p level was upregulated in EC specimens. The inhibition of MALAT1 suppressed the viability, migration, and invasion in EC cell lines. The changes in phenotypes of EC cells were associated with the upregulation of miR-1-3p level and inhibition of CORO1C/TPM3 activity. Furthermore, the results of dual-luciferase assay showed the direct binding of MALAT1 to the seed sequence of miR-1-3p. The suppressed level of miR-1-3p not only induced the activity of CORO1C/TPM3 signaling, but also upregulated MALAT1 expression, indicating the reciprocal regulation between the two factors. The inhibition of MALAT1 also inhibited tumor growth and epithelial-mesenchymal transition (EMT) in mice model, which was reversed by miR-1-3p inhibition. Collectively, MALAT1 was important to the survival and metastasis of EC cells by sponging miR-1-3p.

Hsa_circ_0012563 promotes migration and invasion of esophageal squamous cell carcinoma by regulating XRCC1/EMT pathway

BACKGROUND

Recent reports have indicated that circular RNA (circRNA) may regulate tumorigenesis development. However, the function of circRNAs in esophageal squamous cell carcinoma (ESCC) is unclear.

MATERIAL AND METHOD

The RT-qPCR assay was performed to detect hsa_circ_0012563 expression in ESCC tissues and cell lines. Then, the MTT assay, colony formation assay, flow cytometric assay, and cell migration and invasion assay were performed to examine the function of hsa_circ_0012563. In addition, the RT-PCR and Western blot were used to detect XRCC1 and epithelial-to-mesenchymal transition (EMT) related gene expression.

RESULTS

The RT-qPCR revealed that the hsa_circ_0012563 expression was remarkably upregulated in ESCC tissue and ESCC cell lines. Functionally, downregulation of hsa_circ_0012563 suppressed cell proliferation, migration, and invasion and promoted cell apoptosis. Mechanically, the knockdown of hsa_circ_0012563 inhibited XRCC1-mediated EMT pathway to suppress cell migration and invasion.

CONCLUSIONS

Therefore, these results reveal hsa_circ_0012563 is a critical oncogene and may be a novel biomarker in ESCC.

Identification of BRMS1L as Metastasis Suppressing Gene in Esophageal Squamous Cell Carcinoma

Introduction

Breast cancer metastasis suppressor 1 like (BRMS1-like)was first reported to be a component of the Sin3-HDAC complex, but the role in the progression of cancers was largely unknown. Our previous study reported that BRMS1L promoted the metastasis of breast cancer through facilitating the recruitment of HDAC complex to the promoter FZD10, and hence suppressing the transcription of FZD10.

Methods

In this study, we detected the expression level of BRMS1L in esophageal squamous cell carcinoma (ESCC). The effect of BRMS1L in TE-1D (knockdown) and ECA-109 (overexpression) cell lines was explored by transwell assays, wound healing assays, and cell adhesion assays. Quantitative real‑time PCR, Western blot analysis, and luciferase assays were used to detect the interaction of the CBP/P300-BRMS1L-ITGA7 axis.

Results

In the present study, we found that knockdown of BRMS1L promoted the migration, invasion, and epithelial-mesenchymal transition (EMT). Conversely, overexpression of BRMS1L inhibited the migration and invasion of ESCC. Mechanistically, BRMS1L exerted their metastasis-suppressing role via transcriptionally repress ITGA7 expression. Moreover, we revealed that CBP/p 300 regulated the expression of BRMS1L and might be responsible for the down-regulation of BRMS1L in ESCC.

Conclusion

Collectively, we identified the role of CBP/p300-BRMS1L-ITGA7 axis in the metastasis of ESCC.

miR-92b-3p Functions As A Key Gene In Esophageal Squamous Cell Cancer As Determined By Co-Expression Analysis

Background

Esophageal squamous cell carcinoma (ESCC) is a highly aggressive malignancy. The aims of the present study were to screen the critical miRNA and corresponding target genes that related to development of ESCC by weighted gene correlation network analysis (WGCNA) and investigate the functions by experimental validation.

Methods

Datasets of mRNA and miRNA expression data were downloaded from GEO. The R software was used for data preprocessing and differential expression gene analysis. The differentially expressed protein-coding genes (DEGs) and miRNAs (DEMs) were selected (FDR <0.05 or |Fold Change (FC)| >1.5). Meanwhile, 81 expression data of ESCC patients in TCGA combined with clinic information were applied by WGCNA to create networks. The correlational analyses between each module and clinical parameters were conducted, and enrichment analyses of GO and KEGG were subsequently performed. Then, a series of experiments were conducted in ESCC cells by use of miRNA mimics.

Results

In total, 4,023 DEGs and 328 DEMs were screened. After checking good genes and samples, 3,841 genes (3,696 DEGs and 145 DEMs) were used for WGCNA. As a consequence, altogether 11 gene modules were found. Among them, the brown modules were found to be strongly inversely associated with pathological grade. Meanwhile, has-mir-92b, the only miRNA in brown module, had a positive correlation with grade and negatively correlated with potential target gene (KFL4 and DCS2) in the same module. Furthermore, an increased expression of miR-92b-3p and down-regulated KLF4 and DSC2 protein was detected in the ESCC clinical samples. Up-regulated miR-92b-3p shortened G0/G1 phase and promote ESCC cells invasion and migration. Furthermore, we verified that DSC2 and KFL4 was target genes of miR-92b-3p by luciferase report assay.

Conclusion

WGCNA is an efficient approach to system biology. By this procedure, miR-92b-3p was identified as an ESCC-promoting gene by target KLF4 and DCS2.

miR-145 sensitizes esophageal squamous cell carcinoma to cisplatin through directly inhibiting PI3K/AKT signaling pathway

Background

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer worldwide and is one of the most lethal malignancies. Cisplatin (DDP) is a key drug for ESCC treatment, but the presence of chemotherapy resistance limits the use of DDP. To enhance chemosensitivity to DDP is important for ESCC treatment.

Methods

qRT-PCR and Western blotting detected mRNA and protein expression in ESCC tissues and cells. Luciferase reporter assay assessed the interaction between miR-145 and AKT3. Cell cycle, apoptosis and proliferation were investigated with flow cytometry and MTT assay, respectively. Nude mice xenograft model was established, and immunohistochemistry (IHC) and TUNEL assay were conducted to detect Ki-67 level and apoptosis in xenograft tumor.

Results

Down-regulated miR-145 and up-regulated AKT3 were observed in ESCC tissues and cells. Luciferase reporter assay revealed that miR-145 negatively regulated AKT3 through binding to its 3′-UTR. Overexpression of miR-145 or knockdown of AKT3 promoted DDP-induced cell cycle arrest and apoptosis, as well as reduced IC50 of DDP treatment, which was reversed by AKT3 overexpression. The expression level of MRP1, P-gp, CyclinD1, c-Myc and anti-apoptotic protein Bcl-2 were down-regulated, while pro-apoptotic protein Bax was up-regulated by miR-145. Furthermore, overexpression of miR-145 enhanced the DDP-induced tumor growth suppression in vivo.

Conclusion

miR-145 increased the sensitivity of ESCC to DDP, and facilitated DDP-induced apoptosis, cycle arrest by directly inhibiting PI3K/AKT signaling pathway to decrease multidrug resistance-associated proteins MRP1 and P-gp expression. Improving the efficacy of DDP by boosting the miR-145 level provides a new strategy for treatment of ESCC.

miR-204-5p regulates cell proliferation, invasion, and apoptosis by targeting IL-11 in esophageal squamous cell carcinoma

Esophageal cancer (EC) is the world's eighth most common malignant neoplasm and is ranked as the sixth leading cause of death related to cancer. Aberrant microRNA (miRNA) expression has been reported to be associated with esophageal squamous cell carcinoma. However, the molecular mechanism of miR-204-5p in esophageal squamous cell carcinoma (ESCC) is not clear. Therefore, the aim of this study was to investigate the potential role of miR-204-5p in ESCC. In the present study, we found that miR-204-5p could affect ESCC proliferation, invasion, apoptosis, and cell cycle in cell and mouse models. A dual-luciferase reporter assay showed that miR-204-5p expression was negatively correlated with interleukin-11 (IL-11) expression. IL-11 overexpression reversed the suppressive effects of miR-204-5p in the cell lines. These results indicated that miR-204-5p functions as a tumor suppressor by directly targeting IL-11 in ESCC.

MicroRNA‑212 facilitates the motility and invasiveness of esophageal squamous carcinoma cells

As a tumor-associated microRNA (miR), miR-212 has dual functions; either as an oncogene or a tumor suppressor. A high expression level of miR-212 was reported to be associated with poor outcome in patients with esophageal squamous cell carcinoma (ESCC), however, its role in ESCC progression has not been explored. In the present study, an in vitro cell model of lentivirus-mediated gain-of-function demonstrated promotion of ESCC cell migration and invasion when miR-212 was overexpressed, and no effect on cell proliferation. miR-212 resulted in downregulation of the expression of E-cadherin, β-catenin, vimentin and Twist1. Moreover, it led to increased levels of extracellular matrix (ECM)-degrading enzymes, matrix metalloproteinase-9 and urokinase-type plasminogen activator. Furthermore, berberine inhibited miR-212-induced ESCC cell migration, unlike the PI3K inhibitor LY294002, rapamycin (mTOR inhibitor), 5-(Tetradecyloxy)-2-furoic acid (TOFA; an acetyl-CoA carboxylase 1 inhibitor), metformin and propranolol. These data suggest that miR-212 activates multiple signaling cascades and facilitates ESCC cell motility and invasion by promoting the epithelial-mesenchymal transition and degrading the ECM. Berberine may be a potential therapeutic agent against metastasis in patients with ESCC, who express high levels of miR-212.

RAC1 inhibition reverses cisplatin resistance in esophageal squamous cell carcinoma and induces downregulation of glycolytic enzymes

Development of chemoresistance remains a major challenge in treating esophageal squamous cell carcinoma (ESCC) patients despite treatment advances. However, the role of RAC1 in chemoresistance of ESCC and the underlying mechanisms remain largely unknown. In this study, we found that higher levels of RAC1 expression were associated with poorer prognosis in ESCC patients. Enhanced RAC1 expression increased cell proliferation, migration, and chemoresistance in vitro. Combination therapy using RAC1 inhibitor EHop-016 and cisplatin significantly promoted cell viability inhibition, G2/M phase cycle arrest, and apoptosis when compared to each monotherapy. Mechanistically, glycolysis was significantly downregulated in the RAC1 inhibitor monotherapy group and the combination group via inhibiting AKT/FOXO3a signaling when compared to the control group. Moreover, the silencing of RAC1 inhibited AKT/FOXO3a signaling and cell glycolysis while the upregulation of RAC1 produced an opposite effect. In murine xenograft models, the tumor volume and the expression of glycolytic enzymes were significantly reduced in combination therapy when compared to each monotherapy group. Overall, our study demonstrates that targeting RAC1 with an inhibitor overcomes cisplatin resistance in ESCC by suppressing glycolytic enzymes, which provides a promising strategy for treatment of ESCC in clinical practice.

S1PR1 promotes proliferation and inhibits apoptosis of esophageal squamous cell carcinoma through activating STAT3 pathway

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide, which lacks effective biomarkers for prognosis. Therefore, it is urgent to explore new potential molecular markers to discriminate patients with poorer survival in ESCC.

Methods

Bioinformatics analysis, qRT-PCR, and western blot were applied to investigate S1PR1 expression. CCK-8 assay, colony formation assay, flow cytometry dual staining assay, and immunofluorescence were performed to examine cell proliferation ability and apoptosis rate. Mouse xenograft model of TE-13 cells was established to confirm the roles of S1PR1 in vivo. Gene set enrichment analysis (GSEA) was used to investigate the downstream signaling pathways related to S1PR1 functions. Co-IP was performed to verify the direct binding of S1PR1 and STAT3. Western blot was applied to determine the phosphorylation level of STAT3. Immunohistochemistry was conducted to identify protein expression of S1PR1 and p- STAT3 in tumor tissues.

Results

In the present study, we found that S1PR1 expression was higher in ESCC patients and was a potential biomarker for poor prognosis. Silencing S1PR1 expression inhibited proliferation, and increased apoptosis of ESCC cells, while overexpression of S1PR1 had opposite effects. Mechanistically, S1PR1 played the roles of promoting proliferation and attenuating apoptosis through directly activating p-STAT3. Furthermore, in vivo experiments verified this mechanism.

Conclusion

Our findings indicated that S1PR1 enhanced proliferation and inhibited apoptosis of ESCC cells by activating STAT3 signaling pathway. S1PR1 may serve as a prognostic biomarker for clinical applications.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1369-7) contains supplementary material, which is available to authorized users.

miR-145 Regulates the sensitivity of esophageal squamous cell carcinoma cells to 5-FU via targeting REV3L

Aberrant expression of miR-145 was associated with chemotherapy in multitype cancers. However, the underlying role and molecular mechanism of miR-145 in the sensitivity of esophageal squamous cell carcinoma (ESCC) to 5-FU remained largely unknown. Cell viability was determined by Cell Counting Kit-8 (CCK-8) assay. Gene expression levels were detected by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). Protein expression levels were evaluated by Western blot. TargetScan was used for the prediction of binding sites for miRNA in mRNAs. The interaction between mRNA 3' UTR and miRNA was verified by dual luciferase reporter assay. The results showed that miR-145 was downregulated in ESCC tumor tissues and cells, while REV3L was upregulated in ESCC tumor tissues. Overexpression of miR-145 decreased REV3L mRNA and protein level in ESCC cell line KYSE150, while decreased miR-145 increased REV3L mRNA and protein level in esophageal epithelium cell line (HEEC). In addition, the luciferase activity of ESCC cells was decreased after the treatment of miR-145 mimic and mRNA 3'UTR-WT. Overexpressed miR-145 significantly inhibited cell viability and elevated cell apoptosis rate upon 5-FU treatment. Additionally, transfection of miR-145 mimic further altered expression of key genes involved in cell apoptosis (Bcl-2, Bax, Caspase3) in ESCC cells treated with 5-FU. miR-145 might be a therapeutic target for the treatment of ESCC.

Analysis of the Differentially Expressed Genes Induced by Cisplatin Resistance in Oral Squamous Cell Carcinomas and Their Interaction

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a solid tumor, which originates from squamous epithelium, with about 400,000 new-cases/year worldwidely. Presently, chemoradiotherapy is the most important adjuvant treatment for OSCC, mostly in advanced tumors. However, clinical resistance to chemotherapy still leads to poor prognosis of OSCC patients. Via high-throughput analysis of gene expression database of OSCC, we investigated the molecular mechanisms underlying cisplatin resistance in OSCC, analyzing the differentially expressed genes (DEGs) and their regulatory relationship, to clarify the molecular basis of OSCC chemotherapy resistance and provide a theoretical foundation for the treatment of patients with OSCC and individualized therapeutic targets accurately.

METHODS

Datasets related to "OSCC" and "cisplatin resistance" (GSE111585 and GSE115119) were downloaded from the GEO database and analyzed by GEO2R. Venn diagram was used to obtain drug-resistance-related DEGs. Functional enrichment analysis and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis were performed on DEGs using The Database for Annotation, Visualization and Integrated Discovery (DAVID) software. Protein-protein interaction (PPI) network was constructed by STRING (search tool for recurring instances of neighbouring genes) database. Potential target genes of miRNA were predicted via miRDB, and cBioportal was used to analyze the function and survival of the potential functional genes.

RESULTS

Forty-eight upregulated DEGs and 49 downregulated DEGs were obtained from the datasets, with cutoff as p < 0.01 and |log FC| > 1. The DEGs in OSCC mainly enriched in cell proliferation regulation, and chemokine activity. In PPI network with hub score > 300, the hub genes were identified as NOTCH1, JUN, CTNNB1, CEBPA, and ETS1. Among miRNA-mRNA targeting regulatory network, hsa-mir-200c-3p, hsa-mir-200b-3p, hsa-mir-429, and hsa-mir-139-5p were found to simultaneously regulate multiple hub genes. Survival analysis showed that patients with high CTNNB1 or low CEBPA expression had poor outcome.

CONCLUSIONS

In the OSCC cisplatin-resistant cell lines, NOTCH1, JUN, CTNNB1, CEBPA, and ETS1 were found as the hub genes involved in regulating the cisplatin resistance of OSCC. Members of the miR-200 family may reverse drug resistance of OSCC cells by regulating the hub genes, which can act as potential targets for the treatment of OSCC patients with cisplatin resistance.

MicroRNA-365 suppresses cell growth and invasion in esophageal squamous cell carcinoma by modulating phosphoserine aminotransferase 1

Background

A number of studies have indicated that expression of miRNA-365 (miR-365) is suppressed in various cancers, suggesting its cancer-suppressive role. In the present investigation, we evaluated the regulation and character of miR-365 in human esophageal squamous cell carcinoma (ESCC).

Patients and methods

The tumor tissues and adjacent nontumor tissue samples were collected from 30 patients having ESCC, and the expression levels of miR-365 were studied by quantitative real-time polymerase chain reaction (PCR). MTT and cell invasion by Matrigel assay were done to study the effect of miR-365 on proliferation and metastasis of ESCC cells. An in vivo tumor model was generated by inoculating ESCC cells subcutaneously into BALB nude mice. A study of various biomarkers such as quantitative polymerase chain reaction (qPCR), luciferase activity assay, and Western blot was done to confirm the targets of miR-365.

Results

In tumor tissues, a significant downregulation of miR-365 was observed versus the nontumor adjacent tissues and ESCC cells versus the selected esophageal endothelial cells. It was observed that higher expression levels of miR-365 inhibited the cell invasion, colony formation, growth in esophageal cancer cell lines in vitro, and tumor development in vivo. The study of biomarkers suggests involvement of phosphoserine aminotransferase 1 (PSAT1) as a favorable target for miR-365, and its abnormal expression inverted the miR-365-arbitrated suppression of invasion, viability, and epithelial-mesenchymal transition in esophageal cancer cells. A negative correlation existed with expression of miR-365 and PSAT1 in human esophageal cancer tissue samples.

Conclusion

The study established that miR-365 exhibits tumor-suppressive action via regulating the levels of PSAT1 and leads to invasion and progressiveness of esophageal cancer.

Identification of microRNA Biomarkers of Response to Neoadjuvant Chemoradiotherapy in Esophageal Adenocarcinoma Using Next Generation Sequencing

BACKGROUND

Clinical trials report improved overall survival following neoadjuvant chemoradiotherapy in patients undergoing surgery for esophageal adenocarcinoma, with a 10-15% survival improvement. MicroRNAs (miRNAs) are small noncoding RNAs that are known to direct the behavior of cancers, including response to treatment. We investigated the ability of miRNAs to predict outcomes after neoadjuvant chemoradiotherapy.

METHODS

Endoscopic biopsies from esophageal adenocarcinomas were obtained before neoadjuvant chemoradiotherapy and esophagectomy. miRNA levels were measured in the biopsies using next generation sequencing and compared with pathological response in the surgical resection, and subsequent survival. miRNA ratios that predicted pathological response were identified by Lasso regression and leave-one-out cross-validation. Association between miRNA ratio candidates and relapse-free survival was assessed using Kaplan-Meier analysis. Cox regression and Harrell's C analyses were performed to assess the predictive performance of the miRNAs.

RESULTS

Two miRNA ratios (miR-4521/miR-340-5p and miR-101-3p/miR-451a) that predicted the pathological response to neoadjuvant chemoradiotherapy were found to be associated with relapse-free survival. Pretreatment expression of these two miRNA ratios, pretreatment tumor differentiation, posttreatment AJCC histopathological tumor regression grading, and posttreatment tumor clearance/margins were significant factors associated with survival in Cox regression analysis. Multivariate analysis of the two ratios together with pretherapy factors resulted in a risk prediction accuracy of 85% (Harrell's C), which was comparable with the prediction accuracy of the AJCC treatment response grading (77%).

CONCLUSIONS

miRNA-ratio biomarkers identified using next generation sequencing can be used to predict disease free survival following neoadjuvant chemoradiotherapy and esophagectomy in patients with esophageal adenocarcinoma.

Clinical evaluation of 4 types of microRNA in serum as biomarkers of esophageal squamous cell carcinoma

To the best of our knowledge, there is currently no specific biomarker for esophageal cancer used in clinical practice. However, studies consider that microRNAs (miRNAs/miRs) could have useful implications in clinical practice. The present study aimed to investigate the feasibility of using serum microRNAs as biomarkers for esophageal squamous cell carcinoma (ESCC). Using reverse transcription-quantitative polymerase chain reaction, the expression levels of serum miR-21, miR-25, miR-145 and miR-203 were detected in 31 untreated patients with ESCC (EC-UT), 35 inactive period patients with ESCC following treatment (EC-T), 33 patients with esophageal benign disease (benign) and 32 healthy donors (healthy). Furthermore, the ability of these microRNAs to function as biomarkers of ESCC alone and in combination were investigated. The expression levels of serum miR-21, miR-25 and miR-145 in EC-UT were significantly higher than in the other groups (P<0.001). High sensitivity and specificity were shown when miRNAs were used as biomarkers for ESCC, particularly miR-21 and the combination of miR-21 with miR-145. Comparing EC-UT with healthy, benign and EC-T groups, and a combined group (3 groups set as 1 negative control), the sensitivity and specificity of miR-21 were 71.0 and 96.9, 74.2 and 87.9, 77.4 and 82.9, and 74.2 and 88.0%, respectively. The combined sensitivity and specificity of miR-21 and miR-145 were 71.0 and 96.9, 90.9 and 72.7, 97.1 and 82.9, and 80.6 and 80.0%, respectively. In conclusion, 3 types of miRNA (miR-21, miR-25 and miR-145) in serum could serve as potential biomarkers for ESCC. Furthermore, the expression level of miR-145 in serum was upregulated, compared with the downregulation reported in previous studies in ESCC tissues and cells.

MicroRNA-125b inhibits cell proliferation and induces cell apoptosis in esophageal squamous cell carcinoma by targeting BMF

MicroRNAs (miRNAs) have been reported to regulate the expression of genes by suppressing translation or facilitating mRNA decay. Their expression regulates a wide variety of cellular processes, including the development and progression of cancer. Esophageal squamous cell carcinoma (ESCC) is a malignant cancer with high morbidity and recurrence in Asia. In the present study, the biological function of miR-125b and its underlying mechanism in ESCC were explored. The results revealed that miR-125b expression was significantly decreased in ESCC tissues and cell lines. A decrease in miR-125b was markedly related to lymphatic metastasis in patients. Functional analysis revealed that the overexpression of miR-125b using miR-125b mimics significantly inhibited cell growth and induced cell apoptosis, and increased the G1 phase of the cell cycle in EC109 and EC9706 cells. Notably, the miR-125b inhibitors revealed the opposite effect. Additionally, overexpression of miR-125b significantly inhibited tumor growth in vivo. Furthermore, BCL-2-modifying factor (BMF) was considered to be a potential candidate target of miR-125b based on miRNA target databases. miR-125b negatively regulated BMF expression by directly binding to its 3′-untranslated region. BMF was a functional target of miR-125b in the regulation of cell proliferation, cell apoptosis and the cell cycle in EC109 and EC9706 cells. In clinical ESCC specimens, BMF expression was upregulated, and negatively correlated with that of miR-125b. In conclusion, miR-125b had an antitumor role in ESCC cells mediated by targeting BMF, which can be potentially useful for tumorigenesis in ESCC.

Exploration of gene functions for esophageal squamous cell carcinoma using network-based guilt by association principle

Gene networks have been broadly used to predict gene functions based on guilt by association (GBA) principle. Thus, in order to better understand the molecular mechanisms of esophageal squamous cell carcinoma (ESCC), our study was designed to use a network-based GBA method to identify the optimal gene functions for ESCC. To identify genomic bio-signatures for ESCC, microarray data of GSE20347 were first downloaded from a public functional genomics data repository of Gene Expression Omnibus database. Then, differentially expressed genes (DEGs) between ESCC patients and controls were identified using the LIMMA method. Afterwards, construction of differential co-expression network (DCN) was performed relying on DEGs, followed by gene ontology (GO) enrichment analysis based on a known confirmed database and DEGs. Eventually, the optimal gene functions were predicted using GBA algorithm based on the area under the curve (AUC) for each GO term. Overall, 43 DEGs and 67 GO terms were gained for subsequent analysis. GBA predictions demonstrated that 13 GO functions with AUC>0.7 had a good classification ability. Significantly, 6 out of 13 GO terms yielded AUC>0.8, which were determined as the optimal gene functions. Interestingly, there were two GO categories with AUC>0.9, which included cell cycle checkpoint (AUC=0.91648), and mitotic sister chromatid segregation (AUC=0.91597). Our findings highlight the clinical implications of cell cycle checkpoint and mitotic sister chromatid segregation in ESCC progression and provide the molecular foundation for developing therapeutic targets.

Identification of molecular targets for esophageal carcinoma diagnosis using miRNA-seq and RNA-seq data from The Cancer Genome Atlas: a study of 187 cases

Esophageal carcinoma (ESCA) is one of the most common malignancies worldwide, and its pathogenesis is complex. In this study, we identified differentially expressed miRNAs (DEMs) and genes (DEGs) of ESCA from The Cancer Genome Atlas (TCGA) database. The diagnostic values of DEMs were determined by receiver operating characteristic (ROC) analyses and validated based on data from Gene Expression Omnibus (GEO). The top five DEMs with the best diagnostic values were selected, and their potential targets were predicted by various in silico methods. These target genes were then identified among the DEGs from TCGA. Furthermore, the overlapping genes were subjected to protein-protein interaction (PPI) analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The miRNA-transcription factor (TF) regulatory relations were determined using CircuitsDB and TransmiR. Finally, the regulatory networks of miRNA-TF and miRNA-gene were constructed and analyzed. A total of 136 DEMs and 3541 DEGs were identified in ESCA. The top five DEMs with the highest area under the receiver operating characteristic curve (AUC) values were miRNA-93 (0.953), miRNA-21 (0.928), miRNA-4746 (0.915), miRNA-196a-1 (0.906) and miRNA-196a-2 (0.906). The combined AUC of these five DEMs was 0.985. The KEGG analysis with 349 overlapping genes showed that the calcium signaling pathway and the neuroactive ligand-receptor interaction were the most relevant pathways. The regulatory networks of miRNA-TF and miRNA-gene, including 38 miRNA-TF and 560 miRNA-gene pairs, were successfully established. Our findings may provide new insights into the molecular mechanisms of ESCA pathogenesis. Future research will aim to explore the role of novel miRNAs in the pathogenesis and improve the early diagnosis of ESCA.

ABC Transporters and Their Role in the Neoadjuvant Treatment of Esophageal Cancer

The prognosis of esophageal cancer (EC) is poor, despite considerable effort of both experimental scientists and clinicians. The tri-modality treatment consisting of neoadjuvant chemoradiation followed by surgery has remained the gold standard over decades, unfortunately, without significant progress in recent years. Suitable prognostic factors indicating which patients will benefit from this tri-modality treatment are missing. Some patients rapidly progress on the neoadjuvant chemoradiotherapy, which is thus useless and sometimes even harmful. At the same time, other patients achieve complete remission on neoadjuvant chemoradiotherapy and subsequent surgery may increase their risk of morbidity and mortality. The prognosis of patients ranges from excellent to extremely poor. Considering these differences, the role of drug metabolizing enzymes and transporters, among other factors, in the EC response to chemotherapy may be more important compared, for example, with pancreatic cancer where all patients progress on chemotherapy regardless of the treatment or disease stage. This review surveys published literature describing the potential role of ATP-binding cassette transporters, the genetic polymorphisms, epigenetic regulations, and phenotypic changes in the prognosis and therapy of EC. The review provides knowledge base for further research of potential predictive biomarkers that will allow the stratification of patients into defined groups for optimal therapeutic outcome.

LincRNA-ROR promotes metastasis and invasion of esophageal squamous cell carcinoma by regulating miR-145/FSCN1

Background and objective

In an attempt to discover a new biomarker for early diagnosis and prognosis of esophageal squamous cell carcinoma (ESCC), the regulation mechanism of large intergenic non-coding RNA–regulator of reprogramming (lincRNA-ROR) as a microRNA (miRNA) sponge was studied.

Patients and methods

ROR expression in 91 pairs of ESCC tissue samples and matched adjacent tissues was quantified with real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The ROR–miRNA–mRNA regulatory network was built with 161 esophageal cancer (EC) tissues and 11 adjacent tumor tissues from The Cancer Genome Atlas (TCGA) database. A total of 96 cases of ESCC from TCGA database were collected for analysis on survival rates. The regulatory relationship between ROR, miR-145 and FSCN1 was verified in ESCC cells via qRT-PCR, dual luciferase reporter (DLR) assay, RNA immunoprecipitation (RIP) and Western blotting. The transwell method was used to detect cell migration and invasion.

Results

ROR expression in ESCC tumor tissues was significantly higher than in the adjacent tissues, p<0.001. The survival rate of ESCC patients with high ROR expression levels was lower than that of patients with low ROR expression levels (p<0.001). ROR overexpression could downregulate miR-145 by up to 50% was proven by RIP, DLR assay, and qRT-PCR. Two effective binding sites of ROR to miR-145 were verified by DLR assay. One of the sites has never been cited in the literature. The Western blotting results showed that FSCN1 was a downstream target of ROR/miR-145 (p<0.05). Transwell assays were used to show that overexpression of ROR enhanced migration and invasion behavior of ESCC and miR-145 hindered these effects.

Conclusion

ROR acted as a competitive endogenous RNA (ceRNA) of miR-145 in ESCC. A novel, effective miR-145 binding site of ROR was discovered. The ROR/miR-145/FSCN1 pathway was shown to take part in the metastasis of ESCC. ROR is likely an oncogene biomarker for ESCC early diagnosis and prognosis.

miR-106b promotes cell invasion and metastasis via PTEN mediated EMT in ESCC

MicroRNA (miR)-106b serves an essential function in a variety of human cancer types, particularly in the process of invasion and metastasis. However, the function and mechanism of miR-106b in the invasion and metastasis of esophageal squamous cell carcinoma (ESCC) has remained elusive. In the present study, it was demonstrated that miR-106b was upregulated in ESCC tissues and cell lines. Furthermore, miR-106b expression in ESCC tissues was positively associated with lymphatic metastasis. Inhibition of miR-106b in EC-1 and EC9706 cells decreased not only the invasion and metastasis ability but also the proliferation ability of EC-1 and EC9706 cells. In addition, miR-106b had the ability to induce epithelial-to-mesenchymal transition (EMT) in EC-1 and EC9706 cells. In terms of the underlying mechanism, it was revealed that miR-106b promoted the invasion, metastasis and proliferation ability of EC-1 and EC9706 cells by directly targeting phosphatase and tension homolog (PTEN). Furthermore, miR-106b induced EMT in EC-1 and EC9706 cells by suppressing the expression of PTEN. In summary, the present study revealed that miR-106b contributed to invasion and metastasis in ESCC by regulating PTEN mediated EMT. Downregulation of miR-106b may be a novel strategy for preventing tumor invasion and metastasis.

Potential functions and implications of circular RNA in gastrointestinal cancer

Circular RNAs (circRNAs) are a novel type of endogenous non-coding RNA that have gained attention from researchers for their involvement in multiple biological processes. circRNAs are ubiquitously expressed in eukaryotic cells and regulate gene expression at the transcriptional or post-transcriptional level by interacting with microRNAs (miRNAs) or other molecules. The present review provides an overview of circRNAs, as well as insights into their roles in the development and progression of gastrointestinal cancer. Furthermore, combined with reported data, the present review investigates the potential of circRNAs to become diagnostic or predictive biomarkers of gastrointestinal cancer and may provide novel insights into the treatment of associated cancer types.

Comprehensive bioinformation analysis of the miRNA of PLCE1 knockdown in esophageal squamous cell carcinoma

Phospholipase C epsilon 1 (PLCE1) has been recognized as a novel susceptibility marker for esophageal squamous cell carcinoma (ESCC). The purpose of our study is to investigate its effect on the regulation of miRNA expression so as to translating the data into a novel strategy in control of ESCC. In this study, PLCE1 siRNA and vector-only plasmid were stably transfected into Eca109 and EC9706 cells and then subjected to miRNA array analysis, and quantitative real-time PCR was applied to validate miRNA array data. Then bioinformatic analyses, such as GO and pathway software, were conducted to obtain data on these differentially expressed miRNAs-targeted genes (DEGs) and clarify their function and pathway. The results showed that 36 miRNAs were found to be differentially expressed in PLCE1 siRNA-transfected cells compared with the control cells. In particular, 28 miRNAs were upregulated while 8 miRNAs were downregulated. Gene Ontology analysis showed that the function of the DEGs included cell cycle arrest, cell-matrix adhesion, apoptosis, etc. After this, the major pathways associated with the DEGs were regulation of actin cytoskeleton, TGF-beta signaling pathway, Notch signaling pathway and so on. Taken together, these results showed that the knockdown of PLCE1 may play a vital role in the control of ESCC. Further investigation will reveal and verify the function and pathway of the DEGs for the development of novel treatment strategy for the better control of ESCC.

Molecular mechanisms and clinical implications of miRNAs in drug resistance of esophageal cancer

With the increasing incidence of esophageal cancer, drug resistance is becoming a major obstacle to successful cancer therapy since chemotherapy is regarded as a curative approach to inhibit cancer cell proliferation. Despite the great progress in anticancer treatment achieved during the last decades, the mechanisms of multidrug resistance have not been completely elucidated. Recently, accumulating studies and pre-clinical reports highlighted the role of miRNAs in the drug resistance of esophageal cancer. Areas covered: In this review, we mainly summarized the current advances of miRNAs in esophageal cancer and the mechanisms underlying drug resistance. We also reviewed the potential role of miRNAs as biomarkers for predicting drug response and prognosis. Finally, we envisaged the future orientation and challenges in translating the existing knowledge of drug resistance related miRNAs into clinical applications. Expert commentary: Based on the current knowledge of certain miRNAs, we believe that miRNAs would be helpful to overcome the drug resistance and provide personalized treatment for patients with esophageal cancer. The aims of this study were to provide a comprehensive summary on the emerging role of miRNAs in the drug resistance of esophageal cancer and attract broad attention of more researchers on this field.

Molecular mechanisms and theranostic potential of miRNAs in drug resistance of gastric cancer

INTRODUCTION

Systemic chemotherapy is a curative approach to inhibit gastric cancer cells proliferation. Despite the great progress in anti-cancer treatment achieved during the last decades, drug resistance and treatment refractoriness still extensively persists. Recently, accumulating studies have highlighted the role of miRNAs in drug resistance of gastric cancers by modulating some drug resistance-related proteins and genes expression. Pre-clinical reports indicate that miRNAs might serve as ideal biomarkers and potential targets, thus holding great promise for developing targeted therapy and personalized treatment for the patients with gastric cancer. Areas covered: This review provide a comprehensive overview of the current advances of miRNAs and molecular mechanisms underlying miRNA-mediated drug resistance in gastric cancer. We particularly focus on the potential values of drug resistance-related miRNAs as biomarkers and novel targets in gastric cancer therapy and envisage the future research developments of these miRNAs and challenges in translating the new findings into clinical applications. Expert opinion: Although the concrete mechanisms of miRNAs in drug resistance of gastric cancer have not been fully clarified, miRNA may be a promising theranostic approach. Further studies are still needed to facilitate the clinical applications of miRNAs in drug resistant gastric cancer.

MicroRNA 141 Expression Is a Potential Prognostic Marker of Biliary Tract Cancers

Background/Aims

In recent years, a large number of micro-ribonucleic acids (miRNAs) have been identified as putative prognostic biomarkers for solid cancers because of their role in controlling the expression of oncogenes and tumor suppressor genes. The aim of this study was to verify the utility of miRNA 141 as a prognostic biomarker of biliary tract cancers.

Methods

From June 2010 to June 2012, common bile duct cancer tissue samples and matched noncancerous tissues from the ampulla of Vater were obtained from patients with biliary tract cancer undergoing endoscopic retrograde cholangiopancreatography. Using quantitative real-time polymerase chain reaction assays, we measured the mean relative expression levels of miRNA 141 in both groups of tissues. Overexpression of miRNA 141 was defined as a greater than 2-fold increase in expression levels as determined by the 2^−ΔΔCt method.

Results

In a cohort of 38 patients with biliary tract cancers (seven gallbladder, 13 hilar, and 18 distal bile duct cancers), 26 patients (68.4%) were male, and the median age was 69.5 (52 to 85) years. Nineteen patients (50%) had undergone R0 resection procedures, including three Whipple operations, seven pylorus-preserving pancreaticoduodenectomies, six bile duct resections, and three extended lobectomies. Among the patients who had undergone R0 resection, the overexpression of miRNA 141 was significantly associated with shorter disease-free survival and a greater risk of angiolymphatic invasion. Among the patients who did not undergo R0 resection, miRNA 141 overexpression was significantly associated with reduced overall survival.

Conclusions

Overexpression of miRNA 141 is an indicator of a poor prognosis in patients with biliary tract cancer, suggesting that miRNA 141 may be a valuable prognostic biomarker of this disease.

Biological implications and clinical value of mir-210 in gastrointestinal cancer

Hypoxia, a common feature of tumor microenvironment, is known to accelerate tumor development and growth by promoting the formation of a neoplastic environment. Recent studies have provided a wealth of evidence that miRNAs are significant members of the adaptive response to low oxygen in tumors. miR-210 is one of the hypoxia-induced miRNAs, which has been reported extensively in cancer researches. However, there is no systematic discussion about the role of miR-210 in gastrointestinal cancer. We conducted a literature research in database including PubMed, Elsevier Science Direct and Medline before 16 September 2016, in order to collect articles of miR-210 in gastrointestinal cancer. Areas covered: In the present review, we mainly discuss the following aspects: hypoxia-induced dysregulation of miR-210, the expression of miR-210 and tumorigenesis, the resultant changes of miR-210 targets and its roles in different types of gastrointestinal cancer progression, the diagnostic, therapeutic and prognostic value of miR-210 in gastrointestinal cancer. Expert commentary: Numerous researches have demonstrated the values of miR-210 in cancer diagnosis, prognosis and targeted therapies, especially in gastrointestinal cancers. However, there are also some existing problems and challenges in translating the new research findings into clinical utility. Further investigations and studies are still urgently required.