Advances in prognostic biomarkers for esophageal cancer

Preclinical tumor mouse models for studying esophageal cancer

Preclinical models are extensively employed in cancer research because they can be manipulated in terms of their environment, genome, molecular biology, organ systems, and physical activity to mimic human behavior and conditions. The progress made in in vivo cancer research has resulted in significant advancements, enabling the creation of spontaneous, metastatic, and humanized mouse models. Most recently, the remarkable and extensive developments in genetic engineering, particularly the utilization of CRISPR/Cas9, transposable elements, epigenome modifications, and liquid biopsies, have further facilitated the design and development of numerous mouse models for studying cancer. In this review, we have elucidated the production and usage of current mouse models, such as xenografts, chemical-induced models, and genetically engineered mouse models (GEMMs), for studying esophageal cancer. Additionally, we have briefly discussed various gene-editing tools that could potentially be employed in the future to create mouse models specifically for esophageal cancer research.

JUND facilitates proliferation and angiogenesis of esophageal squamous cell carcinoma cell via MAPRE2 up-regulation

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is a globally aggressive malignant tumor. This study aimed to investigate the mechanism of JUND in ESCC development via MAPRE2.

METHODS

ESCC cells (KYSE-450 and ECA109) were transfected with small interfering RNA (si)-JUND, si-MAPRE2, si-JUND, or pcDNA3.1-MAPRE2. JUND and MAPRE2 expression in ESCC cells was detected with quantitative real-time polymerase chain reaction and western blot. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were used to determine ESCC cell proliferation. Dual-luciferase reporter gene and chromatin immunoprecipitation assays were performed to assess binding between JUND and MAPRE2. Human umbilical vein endothelial cells (HUVECs) were co-cultured with ESCC cell supernatants. Angiogenesis was assessed with an in vitro angiogenesis assay. Western blot was conducted to evaluate the expression of angiogenic proteins [vascular endothelial growth factor A (VEGFA), matrix metallopeptidase 9 (MMP-9), and angiopoietin-2 (ang2)].

RESULTS

The levels of expression of JUND and MAPRE2 were high in ESCC cells. Mechanistically, JUND bound to MAPRE2 promoter and increased MAPRE2 transcription. Downregulation of JUND or MAPRE2 inhibited KYSE-450 and ECA109 cell proliferation and reduced the levels of expression of VEGFA, MMP-9, and ang2 and tube formation in HUVECs co-cultured with ESCC cell supernatants. MAPRE2 upregulation counteracted the inhibitory effects of JUND silencing on cell proliferative and angiogenic capabilities in ESCC.

CONCLUSIONS

JUND promoted MAPRE2 transcription, thereby facilitating cell proliferative and angiogenic abilities in ESCC.

Biomarkers for Early Detection, Prognosis, and Therapeutics of Esophageal Cancers

Esophageal cancer (EC) is the deadliest cancer worldwide, with a 92% annual mortality rate per incidence. Esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) are the two major types of ECs, with EAC having one of the worst prognoses in oncology. Limited screening techniques and a lack of molecular analysis of diseased tissues have led to late-stage presentation and very low survival durations. The five-year survival rate of EC is less than 20%. Thus, early diagnosis of EC may prolong survival and improve clinical outcomes. Cellular and molecular biomarkers are used for diagnosis. At present, esophageal biopsy during upper endoscopy and histopathological analysis is the standard screening modality for both ESCC and EAC. However, this is an invasive method that fails to yield a molecular profile of the diseased compartment. To decrease the invasiveness of the procedures for diagnosis, researchers are proposing non-invasive biomarkers for early diagnosis and point-of-care screening options. Liquid biopsy involves the collection of body fluids (blood, urine, and saliva) non-invasively or with minimal invasiveness. In this review, we have critically discussed various biomarkers and specimen retrieval techniques for ESCC and EAC.

Research Progress on the Predicting Factors and Coping Strategies for Postoperative Recurrence of Esophageal Cancer

Esophageal cancer is one of the malignant tumors with poor prognosis in China. Currently, the treatment of esophageal cancer is still based on surgery, especially in early and mid-stage patients, to achieve the goal of radical cure. However, esophageal cancer is a kind of tumor with a high risk of recurrence and metastasis, and locoregional recurrence and distant metastasis are the leading causes of death after surgery. Although multimodal comprehensive treatment has advanced in recent years, the prediction, prevention and treatment of postoperative recurrence and metastasis of esophageal cancer are still unsatisfactory. How to reduce recurrence and metastasis in patients after surgery remains an urgent problem to be solved. Given the clinical demand for early detection of postoperative recurrence of esophageal cancer, clinical and basic research aiming to meet this demand has been a hot topic, and progress has been observed in recent years. Therefore, this article reviews the research progress on the factors that influence and predict postoperative recurrence of esophageal cancer, hoping to provide new research directions and treatment strategies for clinical practice.

Ferroptosis-Related lncRNA Signature Correlates with the Prognosis, Tumor Microenvironment, and Therapeutic Sensitivity of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is the most prevalent form of esophageal cancer in China and is closely associated with malignant biological characteristics and poor survival. Ferroptosis is a newly discovered iron-dependent mode of cell death that plays an important role in the biological behavior of ESCC cells. The clinical significance of ferroptosis-related long noncoding RNAs (FRLs) in ESCC remains unknown and warrants further research. The current study obtained RNA sequencing profiles and corresponding clinical data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and FRLs were obtained through coexpression analysis. Consensus clustering was employed to divide the subjects into clusters, and immune-associated pathways were identified by functional analysis. The current study observed significant differences in the enrichment scores of immune cells among different clusters. Patients from TCGA-ESCC database were designated as the training cohort. A ten-FRL prediction signature was established using the least absolute shrinkage and selection operator Cox regression model and validated using the GEO cohort and our own independent validation database. Real-time quantitative polymerase chain reaction was used to verify the expression of the ten FRLs, and the ssGSEA analysis was employed to evaluate their function. In addition, the IMvigor database was used to assess the predictive value of the signature in terms of immunotherapeutic responses. Multivariate Cox and stratification analyses revealed that the ten-FRL signature was an independent predictor of the overall survival (OS). Patients with ESCC in the high-risk group displayed worse survival, a characteristic tumor immune microenvironment, and low immunotherapeutic benefits compared to those in the low-risk group. Collectively, the risk model established in this study could serve as a promising predictor of prognosis and immunotherapeutic response in patients with ESCC.

The Emerging Role of Long Non-Coding RNAs in Esophageal Cancer: Functions in Tumorigenesis and Clinical Implications

Esophageal cancer (EC) is one of the most common malignancies of digestive tracts with poor five-year survival rate. Hence, it is very significant to further investigate the occurrence and development mechanism of esophageal cancer, find more effective biomarkers and promote early diagnosis and effective treatment. Long non-coding RNAs (lncRNAs) are generally defined as non-protein-coding RNAs with more than 200 nucleotides in length. Existing researches have shown that lncRNAs could act as sponges, guides, scaffolds, and signal molecules to influence the oncogene or tumor suppressor expressions at transcriptional, post-transcriptional, and protein levels in crucial cellular processes. Currently, the dysregulated lncRNAs are reported to involve in the pathogenesis and progression of EC. Importantly, targeting EC-related lncRNAs through genome editing, RNA interference and molecule drugs may be one of the most potential therapeutic methods for the future EC treatment. In this review, we summarized the biological functions and molecular mechanisms of lncRNAs, including oncogenic lncRNAs and tumor suppressor lncRNAs in EC. In addition, we generalized the excellent potential lncRNA candidates for diagnosis, prognosis and therapy in EC. Finally, we discussed the current challenges and opportunities of lncRNAs for EC.

Development and validation of a survival model for esophageal adenocarcinoma based on autophagy-associated genes

Autophagy is a highly conserved catabolic process which has been implicated in esophageal adenocarcinoma (EAC). We sought to investigate the biological functions and prognostic value of autophagy-related genes (ARGs) in EAC. A total of 21 differentially expressed ARGs were identified between EAC and normal samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were then applied for the differentially expressed ARGs in EAC, and the protein-protein interaction (PPI) network was established. Cox survival analysis and Lasso regression analysis were performed to establish a prognostic prediction model based on nine overall survival (OS)-related ARGs (CAPN1, GOPC, TBK1, SIRT1, ARSA, BNIP1, ERBB2, NRG2, PINK1). The 9-gene prognostic signature significantly stratified patient outcomes in The Cancer Genome of Atlas (TCGA)-EAC cohort and was considered as an independently prognostic predictor for EAC patients. Moreover, Gene set enrichment analysis (GSEA) analyses revealed several important cellular processes and signaling pathways correlated with the high-risk group in EAC. This prognostic prediction model was confirmed in an independent validation cohort (GSE13898) from The Gene Expression Omnibus (GEO) database. We also developed a nomogram with a concordance index of 0.78 to predict the survival possibility of EAC patients by integrating the risk signature and clinicopathological features. The calibration curves substantiated favorable concordance between actual observation and nomogram prediction. Last but not least, Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2), a member of the prognostic gene signature, was identified as a potential therapeutic target for EAC patients. To sum up, we established and verified a novel prognostic prediction model based on ARGs which could optimize the individualized survival prediction in EAC.

PRDM5 suppresses oesophageal squamous carcinoma cells and modulates 14-3-3zeta/Akt signalling pathway

Dysregulation of PR (PRDI-BF1 and RIZ) domain protein 5 (PRDM5) expression has been shown to be associated with the progression of many malignancies. Nevertheless, the role and underlying mechanism of PRDM5 in oesophageal squamous cell carcinoma (ESCC) remain elusive. qRT-PCR was performed to analyze PRDM5 mRNA expression, and western blot was used to determine protein expression of PRDM5, MMP-2, MMP-9, 14-3-3zeta, pan-Akt and phosphorylated Akt expression. CCK-8 staining was employed to evaluate cell proliferation, while wound scratch assay and Transwell assay were carried out to detect cell migration. A tumour xenograft model of ESCC was also established to validate the effect of PRDM5. PRDM5 expression was downregulated in ESCC tissues and positively correlated with the overall survival of ESCC patients. Silencing PRDM5 expression promoted cell proliferation in ESCC cells, while overexpressing PRDM5 inhibited cell proliferation. Moreover, the migratory abilities of ESCC cells were promoted by PRDM5 knockdown but were attenuated by PRDM5 overexpression. Importantly, 14-3-3zeta expression, along with the phosphorylation of Akt, was suppressed by PRDM5 in ESCC cells. In the established tumour xenograft model, PRDM5 regulated ESCC tumour growth as well as the expression of 14-3-3zeta and phosphorylation of Akt protein. In conclusion, PRDM5 suppresses ESCC cell proliferation and migration and negatively regulates 14-3-3zeta/Akt signalling pathway in vitro and in vivo.

LncRNA TUSC8 suppresses the proliferation and migration of esophageal cancer cells by downregulation of VEGFA

Objective: This study aims to determine the expression pattern of long non-coding RNA (lncRNA) TUSC8 in esophageal cancer tissues and cell lines, to investigate its effects on esophageal cancer cell proliferation and migration, and to explore the mechanism of TUSC8-mediated esophageal cancer suppression via VEGFA downregulation.

Patients and Methods: TUSC8 levels in esophageal cancer tissues and cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The influence of TUSC8 on clinical features in esophageal cancer patients was analyzed. After intervening TUSC8 expression in esophageal cancer cells, the proliferative and migratory abilities were examined in OE19 and TE-1 cells through a series of function experiments. The interaction between TUSC8 and VEGFA was assessed by the bioinformatics prediction and dual-luciferase reporter assay. Finally, the co-regulation of TUSC8 and VEGFA on esophageal cancer cell functions was evaluated.

Results: TUSC8 was downregulated in esophageal cancer tissues compared with normal ones. Identically, decreased TUSC8 expression was detected in esophageal cancer cell lines compared with control cells. Low TUSC8 expression predicted poor prognosis in patients with esophageal cancer. Knockdown of TUSC8 promoted the proliferative and migratory abilities in OE19 cells, whereas overexpression of TUSC8 resulted in opposite results in TE-1 cells. VEGFA was confirmed to be a target gene of TUSC8. Overexpression of VEGFA could reverse the regulatory effects of TUSC8 on esophageal cancer cell proliferation and migration.

Conclusions: LncRNA TUSC8 is downregulated in esophageal cancer tissues and cell lines. TUSC8 inhibits the proliferative and migratory abilities in esophageal cancer cells in vitro by negatively regulating VEGFA.

Prognostic value of microvessel density in esophageal squamous cell carcinoma-a systematic review and meta-analysis

OBJECTIVE

Angiogenesis produced by tumor microenvironment is play an important role in development of esophageal squamous cell carcinoma (ESCC). As a quantitative index of angiogenesis, literature has emerged contradictory results about the prognostic role of microvessel density (MVD) in ESCC. The aim of the study was to explore the impact of the correlation between MVD and the prognosis of ESCC based the published evidence.

METHODS

Pubmed and Web of science database were screened for the relationship of MVD with prognostic feature in ESCC up to March, 2021. 11 relevant articles were used for meta-analysis. The following data were extracted from the literature: author, year, country, the patients number of high/low MVD, tumor-node-metastasis (TNM) classification, clinical stage, lymphoid infiltrates, vessel invasion, invasive depth, differential degree and survival rate. The hazard ratio (HR) and odds ratios (OR) with 95% CI were used to assess the associations between MVD and overall survival (OS). Chi-squared test and I² statistics were completed to evaluate the heterogeneity in our study. A random-effects model was used when significant heterogeneity existed (I²>50% and p < 0.05). Egger test was used to calculate the publication bias. Subgroup analysis was stratified by antibody, region, sample capacity to explore the source of heterogeneity.

RESULTS

11 studies with 1055 patients were analyzed. Our results suggested that high MVD is an important factor to advanced TNM classification and clinical stage, and the high MVD is positive correlation with the lymph node invasion and vascular invasion(p < 0.05) in ESCC, but irrelevant to poor differential and invasive depth(p > 0.05). The result also indicated that low MVD is a benefit factor to prolong the survival rate (p < 0.05). And the source of the heterogeneity maybe is that the antibody used to detect the MVD was not consistent, patient number was not large enough and the count method on MVD.

CONCLUSION

Across multiple studies, high MVD is correlated with clinicopathological criteria of poor prognosis and survival in ESCC. MVD could be the quantitative index to reactive angiogenesis and may play a pivotal role in ESCC development and progression. MVD may represent a valuable addition to current pathologic analysis and help to guide prognosis and treatment.

Mitochondrial calcium uniporter promotes cell proliferation and migration in esophageal cancer

Increasing evidence has suggested that mitochondrial calcium uniporter (MCU) is involved in various types of cancer. However, its functions remain unclear in esophageal cancer. The aim of the present study was to explore its abnormal expression and clinical implications in esophageal cancer. A total of 110 patients with esophageal cancer were enrolled in the study. Western blotting was performed to examine the protein expression levels of MCU in 8 pairs of esophageal cancer and adjacent normal tissues. Using immunochemistry, a total of 110 esophageal cancer specimens were analyzed to identify the association between MCU expression and clinicopathological features of patients with esophageal cancer. Furthermore, immunofluorescence of MCU was performed. Pearson's correlation analysis was performed between MCU and hypoxia inducible factor (HIF)-1α/VEGF/E-cadherin/Vimentin expression based on western blotting. After KYSE-150 and TE-1 cells were treated with the MCU agonist Spermine and a small interfering RNA against MCU (si-MCU), a series of functional assays were performed, including Cell Counting Kit-8, colony formation and Transwell assays. The results revealed that, compared with in adjacent normal tissues, MCU was highly expressed in esophageal cancer tissues. MCU expression was significantly associated with depth of invasion, lymph node metastasis, TNM stage and distant metastasis. Moreover, MCU was significantly correlated with HIF-1α/VEGF/E-cadherin/Vimentin in esophageal cancer tissues. MCU overexpression promoted VEGF, MMP2, Vimentin and N-cadherin expression, while it inhibited E-cadherin expression in KYSE-150 and TE-1 cells, and opposite results were observed after transfection with si-MCU. Furthermore, MCU overexpression accelerated the proliferation and migration of KYSE-150 and TE-1 cells. Thus, the current findings suggested that high MCU expression may participate in cell proliferation, migration and epithelial-mesenchymal transition in esophageal cancer.

Epidemiology of esophageal cancer: update in global trends, etiology and risk factors

Esophageal cancer is the eighth most common type of cancer worldwide and constitutes the sixth leading cause of cancer deaths. It is characterized by its high mortality rate, poor prognosis at time of diagnosis and variability based on geographic location. Present day, the prevalence of esophageal cancer is in transition. Although esophageal squamous cell carcinoma continues to be the most prevalent type worldwide, esophageal adenocarcinoma is quickly becoming the most prevalent type in developed countries. Risk factors for the development of esophageal squamous cell carcinoma include low socioeconomic status, consumption of tobacco, alcohol, hot beverages, and nitrosamines. Additionally, micronutrient deficiencies have also been linked to the development of esophageal squamous cell cancer. These include vitamin C, vitamin E, and folate. With respect to esophageal adenocarcinoma, risk factors include Barrett's esophagus, gastroesophageal reflux disease, obesity, and tobacco consumption. Screening for esophageal cancer will likely play an essential role in prevention, and consequently, mortality in the future. Present day, there are no established guidelines for esophageal squamous cell cancer screening. Guidelines for esophageal adenocarcinoma are more well established but lack concrete evidence in the form of randomized controlled trials. This review will discuss the epidemiology, risk factors, and current prevention strategies for esophageal cancer in depth. It is our aim to raise awareness on the aforementioned topics to increase public health efforts in eradicating this disease.

Non-coding RNAs in regulating gastric cancer metastasis

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, and mortality remains high, especially in East Asia. At present, the main method to diagnose gastric cancer is pathological biopsy. At the time of diagnosis, most patients have been diagnosed with advanced cancer and metastasis. The treatment of gastric cancer patients is mainly radical surgical resection and chemoradiotherapy, while patients with metastatic tumor have great challenges to radical surgery and are prone to drug resistance. Metastasis is an important factor affecting tumor development. In addition, evidence accumulated in the literature indicates that non-coding RNA plays a key role in tumor metastasis. This article reviews the role of ncRNAs in gastric cancer metastasis and discusses the regulatory mechanism in the development and treatment of gastric cancer.