Current status of esophageal cancer treatment

Severe postoperative complications after minimally invasive esophagectomy reduce the long-term prognosis of well-immunonutrition patients with locally advanced esophageal squamous cell carcinoma

BACKGROUND

While severe postoperative complications (SPCs) impact cancer prognosis, their effect on locally advanced esophageal squamous cell carcinoma (ESCC) patients with varying immunonutritional statuses after minimally invasive esophagectomy (MIE) is unclear.

METHODS

This retrospective study analyzed 442 patients with locally advanced ESCC who underwent MIE, investigating the relationship between SPCs and survival based on preoperative immunonutritional status, determined by the prognostic nutritional index (PNI). Nomograms were developed for patients with preserved immunonutritional status using Cox regression, and their performance was assessed.

RESULTS

Of the patients, 102 (23.1%) experienced SPCs after MIE. Five-year overall survival (OS) and disease-free survival (DFS) were significantly different between SPCs and non-SPCs groups (p < 0.001). In the preserved immunonutritional group, SPCs significantly reduced 5-year OS (p = 0.008) and DFS (p = 0.011), but not in the poor immunonutritional group (OS p = 0.152, DFS p = 0.098). Multivariate Cox regression identified SPCs as an independent risk factor for OS (HR = 1.653, p = 0.013) and DFS (HR = 1.476, p = 0.039). A nomogram for predicting OS and DFS in preserved immunonutritional patients demonstrated excellent performance.

CONCLUSIONS

SPCs significantly affect prognosis in ESCC patients with preserved immunonutritional status after MIE. Nomograms based on SPCs can predict OS and DFS in these patients.

Exosomes in esophageal cancer: a promising frontier for liquid biopsy in diagnosis and therapeutic monitoring

Esophageal cancer is a common and lethal digestive system malignancy, and both treatment efficacy and patient survival rates face significant challenges. In recent years, exosomes have emerged as crucial mediators of intercellular communication, demonstrating tremendous clinical potential, particularly in the diagnosis, treatment, and prognostic evaluation of esophageal cancer. These exosomes not only serve as biomarkers for early diagnosis and prognosis but also modulate tumor growth, metastasis, and drug resistance by delivering bioactive molecules. Importantly, exosomes can act as carriers for esophageal cancer-related therapeutic agents, optimizing gene therapy strategies to enhance efficacy while reducing toxicity and side effects. Despite facing challenges in clinical applications such as purification, enrichment, and standardization of analytical methods, exosomes maintain broad prospects for application in esophageal cancer treatment, with the potential to significantly improve patient outcomes and quality of life. This review focuses on the innovative role of exosomes in the early diagnosis of esophageal cancer, exploring their application value and safety in disease monitoring and assessment of treatment response. Furthermore, this study outlines the challenges and limitations of transitioning exosome research from basic studies to clinical applications, as well as potential solutions and future research directions to address these obstacles.

The Impact of Tumor Stage and Histopathology on Survival Outcomes in Esophageal Cancer Patients over the Past Decade

BACKGROUND

Esophageal cancer (EC) is the sixth leading cause of cancer-related mortality worldwide, continuing to be a significant public health concern. The purpose of this study is to assess the impact of staging and histopathology of EC on associated mortality. The study also aims to further investigate clinical characteristics, prognostic factors, and survival outcomes in patients diagnosed with EC between 2010 and 2017. Furthermore, we analyzed the interaction between tumor histology and staging and the risk of mortality.

METHODS

A total of 24,011 patients diagnosed with EC between 2010 and 2017 in the United States were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database. Demographic parameters, tumor stage, and histologic subtypes were analyzed and associated overall mortality (OM) and cancer-specific mortality (CSM) were measured across all subgroups. Covariates reaching the level of statistical significance, demonstrable by a p-value equal to or less than 0.01, were incorporated into a multivariate Cox proportional hazards model. A hazard ratio greater than 1 was indicative of an increased risk of mortality in the presence of the variable under discussion. Additionally, the study explores the interaction between histology and tumor stage on outcomes.

RESULTS

The majority of patients were male (80.13%) and non-Hispanic white (77.87%), with a predominant age at diagnosis of between 60 and 79 years (59.86%). Adenocarcinoma was the most common tumor subtype (68.17%), and most patients were diagnosed at a distant stage (41.29%). Multivariate analysis revealed higher mortality risks for males, older patients, unmarried individuals, and those with advanced-stage tumors. Higher income, receiving radiation or chemotherapy, and undergoing surgery were associated with lower mortality. Tumor subtype significantly influenced mortality, with squamous cell carcinoma and neuroendocrine tumors showing higher hazard ratios compared to adenocarcinoma. Adenocarcinoma is linked to a poorer prognosis at advanced stages, whereas the opposite trend is observed for SCC.

CONCLUSIONS

The study identifies significant demographic and clinicopathologic factors influencing mortality in esophageal cancer patients, highlighting the importance of early diagnosis and treatment intervention. Future research should focus on tailored treatment strategies to improve survival outcomes in high-risk groups and to understand the interaction between tumor histology and tumor stage.

Prognostic value of sarcopenia and inflammatory indices synergy in patients with esophageal squamous cell carcinoma undergoing chemoradiotherapy

BACKGROUND AND PURPOSE

Sarcopenia has been demonstrated to be adversely correlated with the prognosis of various cancers. Our study aimed to estimate the prognostic value of sarcopenia in conjunction with inflammatory indices [neutrophil-to-lymphocyte ratio (NLR)] for evaluating the prognosis of patients with esophageal squamous cell carcinoma (ESCC) undergoing chemoradiotherapy.

MATERIALS AND METHODS

This study retrospectively analyzed 255 patients with ESCC who received chemoradiotherapy from January 2012 to December 2018. Multivariate Cox regression analysis was employed to identify prognostic values of assessed factors following a novel prognostic scoring system (SMI-NLR), covering sarcopenia and NLR during different treatment courses.

RESULTS

Kaplan-Meier analysis revealed significantly greater overall survival (OS) rates in the nonsarcopenia group than in the sarcopenia group (P = 0.011). The low NLR group (< 4.84) demonstrated significantly higher OS rates than the high NLR group (≥ 4.84) (P < 0.001). The SMI-NLR prognostic model was established through multivariate analysis, revealing that Karnofsky performance status [hazard ratio (HR) = 0.285; 95% confidence interval (CI) = 0.117-0.699; P = 0.006], clinical staging (HR = 5.223; 95% CI = 1.879-14.514; P = 0.002), and preSMI-NLR (HR = 0.544; 95% CI = 0.330-0.898; P = 0.017) were independent factors affecting the prognosis of patients with ESCC. Nomograms were constructed based on these data providing more accurate 1-, 3-, and 5-year survival rates for patients with ESCC.

CONCLUSION

Our study indicates the effectiveness of the combined sarcopenia and NLR prognostic model for the prognostic evaluation of patients with ESCC having undergone chemoradiotherapy.

Construction and validation of classification models for predicting the response to concurrent chemo-radiotherapy of patients with esophageal squamous cell carcinoma based on multi-omics data

BACKGROUND

Concurrent chemo-radiotherapy (CCRT) is the preferred non-surgical treatment for patients with locally advanced esophageal squamous cell carcinoma (ESCC). Unfortunately, some patients respond poorly, which leads to inappropriate or excessive treatment and affects patient survival. To accurately predict the response of ESCC patients to CCRT, we developed classification models based on the clinical, serum proteomic and radiomic data.

METHODS

A total of 138 ESCC patients receiving CCRT were enrolled in this study and randomly split into a training cohort (n = 92) and a test cohort (n = 46). All patients were classified into either complete response (CR) or incomplete response (non-CR) groups according to RECIST1.1. Radiomic features were extracted by 3Dslicer. Serum proteomic data was obtained by Olink proximity extension assay. The logistic regression model with elastic-net penalty and the R-package "rms" v6.2-0 were applied to construct classification and nomogram models, respectively. The area under the receiver operating characteristic curves (AUC) was used to evaluate the predictive performance of the models.

RESULTS

Seven classification models based on multi-omics data were constructed, of which Model-COR, which integrates five clinical, five serum proteomic, and seven radiomic features, achieved the best predictive performance on the test cohort (AUC = 0.8357, 95 % CI: 0.7158-0.9556). Meanwhile, patients predicted to be CR by Model-COR showed significantly longer overall survival than those predicted to be non-CR in both cohorts (Log-rank P = 0.0014 and 0.027, respectively). Furthermore, two nomogram models based on multi-omics data also performed well in predicting response to CCRT (AUC = 0.8398 and 0.8483, respectively).

CONCLUSION

We developed and validated a multi-omics based classification model and two nomogram models for predicting the response of ESCC patients to CCRT, which achieved the best prediction performance by integrating clinical, serum Olink proteomic, and radiomic data. These models could be useful for personalized treatment decisions and more precise clinical radiotherapy and chemotherapy for ESCC patients.

Unveiling Therapeutic Targets for Esophageal Cancer: A Comprehensive Review

Esophageal cancer is a highly aggressive and deadly disease, ranking as the sixth leading cause of cancer-related deaths worldwide. Despite advances in treatment, the prognosis remains poor. A multidisciplinary approach is crucial for achieving complete remission, with treatment options varying based on disease stage. Surgical intervention and endoscopic treatment are used for localized cancer, while systemic treatments like chemoradiotherapy and targeted drug therapy play a crucial role. Molecular markers such as HER2 and EGFR can be targeted with drugs like trastuzumab and cetuximab, and immunotherapy drugs like pembrolizumab and nivolumab show promise by targeting immune checkpoint proteins. Epigenetic modifications offer new avenues for targeted therapy. Treatment selection depends on factors like stage, tumor location, and patient health, with post-operative and rehabilitation care being essential. Early diagnosis, appropriate treatment, and supportive care are key to improving outcomes. Continued research is needed to develop effective targeted drugs with minimal side effects. This review serves as a valuable resource for clinicians and researchers dedicated to enhancing esophageal cancer treatment outcomes.

Biological roles of RNA m7G modification and its implications in cancer

M7G modification, known as one of the common post-transcriptional modifications of RNA, is present in many different types of RNAs. With the accurate identification of m7G modifications within RNAs, their functional roles in the regulation of gene expression and different physiological functions have been revealed. In addition, there is growing evidence that m7G modifications are crucial in the emergence of cancer. Here, we review the most recent findings regarding the detection techniques, distribution, biological functions and Regulators of m7G. We also summarize the connections between m7G modifications and cancer development, drug resistance, and tumor microenvironment as well as we discuss the research's future directions and trends.

Thoracolaparoscopic esophagectomy for esophageal cancer with a cervical incision to extract specimen

BACKGROUND

Surgical treatment is the most important and effective therapy for resectable esophageal cancer. Minimally invasive esophagectomy (MIE) can reduce surgical trauma. A neck incision can be performed for extraction of surgical specimen. This study was performed to investigate the safety and feasibility of neck incision to extract surgical specimen in thoracolaparoscopic esophagectomy for esophageal cancer.

MATERIALS AND METHODS

Thirty-four patients who experienced thoracolaparoscopic esophagectomy for esophageal cancer and a neck incision for extraction of surgical specimen were enrolled. The clinical, surgical and follow-up data were analyzed.

RESULTS

The procedure was successful in all patients (100%), with a neck incision to extract the surgical specimen. The median surgical time was 309 min, and the median blood loss was 186 ml, with the mean length of hospital stay of 11.5 days. Pulmonary complications occurred in 8 patients (23.5%). Anastomotic leakage occurred in 5 patients (14.7%), with one patient being treated conservatively to recover and four (11.8%) who received interventional drainage. One patient with interventional drainage died of severe infection, resulting in a 30-day surgical mortality of 2.9% (n = 1). Gastrointestinal complications happened in 5 patients (14.7%), including ileus in three patients and anastomotic stenosis in two patients. Follow-up was performed at a median time of 20 months (interquartile range, 14-32 months), with no death during this period. No recurrence was found in the first 12 months after radical resection.

CONCLUSION

The cervical incision to extract surgical specimen is safe and feasible with improved cosmetic effect in thoracolaparoscopic esophagectomy for esophageal cancer.

Construction and validation of a novel and superior protein risk model for prognosis prediction in esophageal cancer

Esophageal cancer (EC) is recognized as one of the most common malignant tumors in the word. Based on the biological process of EC occurrence and development, exploring molecular biomarkers can provide a good guidance for predicting the risk, prognosis and treatment response of EC. Proteomics has been widely used as a technology that identifies, analyzes and quantitatively acquires the composition of all proteins in the target tissues. Proteomics characterization applied to construct a prognostic signature will help to explore effective biomarkers and discover new therapeutic targets for EC. This study showed that we established a 8 proteins risk model composed of ASNS, b-Catenin_pT41_S45, ARAF_pS299, SFRP1, Vinculin, MERIT40, BAK and Atg4B via multivariate Cox regression analysis of the proteome data in the Cancer Genome Atlas (TCGA) to predict the prognosis power of EC patients. The risk model had the best discrimination ability and could distinguish patients in the high- and low-risk groups by principal component analysis (PCA) analysis, and the high-risk patients had a poor survival status compared with the low-risk patients. It was confirmed as one independent and superior prognostic predictor by the receiver operating characteristic (ROC) curve and nomogram. K-M survival analysis was performed to investigate the relationship between the 8 proteins expressions and the overall survival. GSEA analysis showed KEGG and GO pathways enriched in the risk model, such as metabolic and cancer-related pathways. The high-risk group presented upregulation of dendritic cells resting, macrophages M2 and NK cells activated, downregulation of plasma cells, and multiple activated immune checkpoints. Most of the potential therapeutic drugs were more appropriate treatment for the low-risk patients. Through adequate analysis and verification, this 8 proteins risk model could act as a great prognostic evaluation for EC patients and provide new insight into the diagnosis and treatment of EC.

Prevalence, nature and trajectory of dysphagia postoesophageal cancer surgery: a prospective longitudinal study protocol

INTRODUCTION

Dysphagia is a common problem following oesophagectomy, and is associated with aspiration pneumonia, malnutrition, weight loss, prolonged enteral feeding tube dependence, in addition to an extended in-hospital stay and compromised quality of life (QOL). To date, the prevalence, nature and trajectory of post-oesophagectomy dysphagia has not been systematically studied in a prospective longitudinal design. The study aims (1) to evaluate the prevalence, nature and trajectory of dysphagia for participants undergoing an oesophagectomy as part of curative treatment, (2) to determine the risk factors for, and post-operative complications of dysphagia in this population and (3) to examine the impact of oropharyngeal dysphagia on health-related QOL across time points.

METHODS AND ANALYSIS

A videofluoroscopy will be completed and analysed on both post-operative day (POD) 4 or 5 and at 6-months post-surgery. Other swallow evaluations will be completed preoperatively, POD 4 or 5, 1-month and 6-month time points will include a swallowing screening test, tongue pressure measurement, cough reflex testing and an oral hygiene evaluation. Nutritional measurements will include the Functional Oral Intake Scale to measure feeding tube reliance, Malnutrition Screening Tool and the Strength, Assistance With Walking, Rise From a Chair, Climb Stairs and Falls questionnaire. The Reflux Symptom Index will be administered to investigate aerodigestive symptoms commonly experienced by adults post-oesophagectomy. Swallowing-related QOL outcome measures will be determined using the European Organisation for Research and Treatment of Cancer QLQ-18, MD Anderson Dysphagia Inventory and the Swallowing Quality of Life Questionnaire.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Tallaght University Hospital/St. James' Hospital Research Ethics Committee (JREC), Dublin, Ireland (Ref. No. 2021-Jul-310). The study results will be published in peer-reviewed journals and presented at national and international scientific conferences.

KIFC3 promotes proliferation, migration and invasion of esophageal squamous cell carcinoma cells by activating EMT and β-catenin signaling

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies. A total of 45 kinesin superfamily proteins (KIFs) have been identified in humans, among which several family members have demonstrated varied functions in tumor pathobiology via different mechanisms, including regulation of cell cycle progression and metastasis. KIFC3 has microtubule motor activity and is involved in cancer cell invasion and migration, as well as survival. However, the role of KIFC3 in ESCC is still unknown.

AIM

To evaluate the role of KIFC3 in ESCC and the underlying mechanisms.

METHODS

Expression of KIFC3 was evaluated in ESCC tissues and adjacent normal esophageal tissues. The prognostic value of KIFC3 was analyzed using Kaplan–Meier Plotter. Colony formation, EdU assays, cell cycle analysis, Transwell assay, immunofluorescence, and western blotting were performed in ESCC cell lines after transfection with pLVX-Puro-KIFC3-shRNA- and pLVX-Puro-KIFC3-expressing lentiviruses. A xenograft tumor model in nude mice was used to evaluate the role of KIFC3 in tumorigenesis. Inhibitor of β-catenin, XAV-939, was used to clarify the mechanism of KIFC3 in ESCC. To analyze the differences between groups, t test and nonparametric tests were used. P < 0.05 was considered statistically significant.

RESULTS

Immunohistochemical staining indicated that KIFC3 was upregulated in ESCC tissues compared with adjacent normal tissues. Kaplan–Meier Plotter revealed that overexpressed KIFC3 was associated with poor prognosis in ESCC patients. Colony formation and EdU assay showed that KIFC3 overexpression promoted cell proliferation, while KIFC3 knockdown inhibited cell proliferation in ESCC cell lines. In addition, cell cycle analysis showed that KIFC3 overexpression promoted cell cycle progression. KIFC3 knockdown suppressed ESCC tumorigenesis in vivo. Transwell assay and western blotting revealed that KIFC3 overexpression promoted cell migration and invasion, as well as epithelial–mesenchymal transition (EMT), while KIFC3 knockdown showed the opposite results. Mechanistically, KIFC3 overexpression promoted β-catenin signaling in KYSE450 cells; however, the role of KIFC3 was abolished by XAV-939, the inhibitor of β-catenin signaling.

CONCLUSION

KIFC3 was overexpressed in ESCC and was associated with poor prognosis. Furthermore, KIFC3 promoted proliferation, migration and invasion of ESCC via β-catenin signaling and EMT.

METTL3 Is Associated With the Malignancy of Esophageal Squamous Cell Carcinoma and Serves as a Potential Immunotherapy Biomarker

Methyltransferase-like 3 (METTL3) is an RNA methyltransferase mediating N6 methyladenosine (m6A) modification. Its role in cancer pathogenesis and progression has attracted increasing attention. However, the immunological role, possible immune mechanism, and clinical significance of METTL3 in esophageal squamous cell carcinoma (ESCC) remain to be confirmed. The Tumor Genome Atlas (TCGA) provided clinical and transcriptome sequencing data for this study (162 tumor tissue samples and 11 normal tissue samples), while the Immunology Database and Analysis Portal (immport, https://www.immport.org/home) provided 2483 immune-related genes. METTL3 was substantially expressed in ESCC and linked to poor prognosis in ESCC, according to the findings. Functional analysis revealed that METTL3 is mainly involved in chromosomal homologous recombination and DNA mismatch repair processes, which could be potential mechanisms for tumor disease development and progression. Analysis on the TISIDB website shows that effector memory CD8 T cells, NK cells, neutrophils and other cells are highly correlated with METTL3 expression. We screened immune genes associated with METTL3 by Spearman’s analysis and performed functional analysis. These immune genes were mostly linked with immune processes, such as cytokine receptors, the MAPK signaling pathway, and natural killer cell-mediated cytotoxicity, indicating that METTL3 is a key molecule in the immune regulation of esophageal cancer. In addition, based on METTL3-related immune genes, we separated the patients into several subgroups and constructed a prognostic prediction model consisting of six immune genes. As an independent prognostic indicator for ESCC, the risk score of this model can be employed. A nomogram was also developed to accurately evaluate individual prognoses based on clinical indicators and risk scores. In summary, this study suggests that METTL3 is not only a potential pathogenic molecule for esophageal carcinogenesis and progression but also a potential biological marker for forecasting ESCC patient prognosis and could serve as a basis for clinical decision making.

Cytokine Interaction With Cancer-Associated Fibroblasts in Esophageal Cancer

Esophageal cancer (EC) is a highly aggressive cancer with poor outcomes under current treatment regimens. More recent findings suggest stroma elements, specifically cancer-associated fibroblasts (CAFs), play a role in disease occurrence and progression. Cancer-associated fibroblasts are largely the product of converted fibroblasts, but a variety of other local cell types including epithelial cells, endothelial cells, and mesenchymal cells have also been shown to transform to CAFs under the correct conditions. Cancer-associated fibroblasts primarily function in the communication between the tumor microenvironment and cancer cells via cytokine and chemokine secretions that accentuate immunosuppression and cancer growth. Cancer-associated fibroblasts also pose issues for EC treatment by contributing to resistance of current chemotherapeutics like cisplatin. Targeting this cell type directly proves difficult given the heterogeneity between CAFs subpopulations, but emerging research provides hope that treatment is on the horizon. This review aims to unravel some of the complexities surrounding CAFs’ impact on EC growth and therapy.

Galangin Enhances Anticancer Efficacy of 5-Fluorouracil in Esophageal Cancer Cells and Xenografts Through NLR Family Pyrin Domain Containing 3 (NLRP3) Downregulation

BACKGROUND Galangin is believed to exert antioxidant effects by inhibition of the NLR family pyrin domain containing 3 (NLRP3) inflammasome, which has been linked to chemotherapy sensitivity in cancers. In this study, we explored the synergistic effect of galangin in combination with the chemotherapy agent 5-fluorouracil (5-FU) in esophageal cancer cells and xenografts. MATERIAL AND METHODS The esophageal squamous epithelium cell line Het-1A and 2 human esophageal cancer cell lines (Eca109, OE19) were used to investigate the effect of galangin with or without 5-FU in vitro through proliferation and invasion analyses, while apoptosis was analyzed in cancer cells. Furthermore, a subcutaneous xenograft tumor model in mice was used to study cancer development in vivo. RESULTS Compared with 5-FU monotherapy, combined galangin and 5-FU treatment reduced human esophageal cancer cell growth activities and invasion abilities. The results suggested that galangin had a chemotherapy-sensitized synergistic antitumor effect induced by 5-FU. The susceptibility of cancer cells to apoptosis, which is linked with chemotherapy sensitivity, was induced by 5-FU and further enhanced by galangin. NLRP3 was identified as being significantly activated by 5-FU, but galangin treatment reversed the effect and inhibited NLRP3 expression, which was accompanied by downregulated interleukin-1b levels. Further investigation showed that the induced apoptotic cascade can be mostly reversed by incubation with an NLRP3 activator, irrespective of AKT signaling. Using xenograft mouse models, we found that galangin exposure further restrained cancer development after 5-FU treatment and increased sensitivity to chemotherapy by suppressing the NLRP3 inflammasome pathway. CONCLUSIONS Our results indicated that galangin played a synergistic anticancer role through NLRP3 inflammasome inhibition when paired with FU-5.

Research on esophageal cancer: With personal perspectives from studies in China and Kenya

The most common form of esophageal cancer (EC), esophageal squamous cell carcinoma (ESCC), is prevalent in many unindustrialized societies, among people with lower socioeconomic status and those who frequently use tobacco and alcohol. In some areas, ESCC mortality ranked top among all cancer. In this review, we begin with discussions of the extensive research on EC in Linxian in northern China that started 60 years ago and the recent studies in Kenya from our personal perspectives. Based on the results obtained from these studies and information from the literature, we summarize our current understanding about the risk factors for ESCC including lifestyle factors (smoking, alcohol, consumption of food and beverages at high temperature and other unhealthy habits), poor diet and nutritional insufficiencies and genetic susceptibility. Elimination or minimization of these environmental risk factors, as well as early detection and treatment of precancerous lesions, would be effective means for the prevention of ESCC. Current knowledge of molecular alterations in ESCC (gene mutations, hypermethylation and amplification or overexpression), as well as treatment of ESCC and the potential of targeted therapy, are also discussed. Finally, we propose effective approaches for the prevention of ESCC by adapting a healthy lifestyle, including a healthy diet that would also prevent other diseases. Community outreach, public education and international collaboration are important for achieving this public health goal.

Cardamonin inhibits the progression of oesophageal cancer by inhibiting the PI3K/AKT signalling pathway

Background: Oesophageal cancer is the most common malignant tumour with a poor prognosis, and the current treatment methods are limited. Therefore, identifying effective treatment methods has become a research hotspot. Cardamonin (CAR) is a natural chalcone compound and has been reported to play an anticancer role in several cancers. However, its function in oesophageal cancer and the possible underlying mechanism are still unclear. The purpose of this study was to demonstrate the anticancer effect of CAR on oesophageal cancer in vivo and in vitro and to explore the underlying mechanism.

Materials and Methods: MTT, crystal violet, and colony formation assays were used to detect oesophageal cancer cell proliferation. The effects of CAR on oesophageal cancer cell migration and invasion were detected by wound healing assay and Transwell assay. Hoechst 33258 staining and flow cytometry were used to detect cell apoptosis. Protein expression levels were detected by Western blot. A tumour xenograft model was established to further test the effect of CAR on the growth of oesophageal cancer in vivo.

Results: The results showed that CAR inhibited the proliferation, migration, and invasion of oesophageal cancer cells in a concentration-dependent manner and induced apoptosis. Furthermore, the Western blot assay showed that CAR could suppress metastasis by inhibiting epithelial-mesenchymal transition (EMT) as indicated by downregulated expression of the mesenchymal markers N-cadherin and vimentin, the EMT transcription factor Snail, and matrix metalloproteinases (MMPs) and upregulated expression of the epithelial marker E-cadherin. CAR was associated with upregulation of the pro-apoptotic proteins Bax and Bad and downregulation of the anti-apoptotic protein Bcl-2 and triggered the mitochondrial apoptosis pathway, which in turn promoted caspase-3 activation and subsequent cleavage of PARP; however, the mitochondria-related apoptotic effects induced by CAR were blocked by caspase inhibitor Z-VAD-FMK pretreatment, which prevented programmed cell death triggered by CAR. In addition, CAR reduced the phosphorylation level of downstream effector molecules of phosphatidylinositol 3 kinase (PI3K) in a dose-dependent manner, and treatment with the PI3K agonist 740Y-P could partially reverse the anticancer effect of CAR, demonstrating that CAR played an antitumour role by inhibiting the PI3K/AKT signalling pathway in oesophageal cancer cells. Moreover, the EC9706 xenograft model further confirmed that CAR can significantly inhibit tumour growth in vivo.

Conclusion: In summary, CAR exhibited a strong anticancer effect on human oesophageal cancer cells and promoted apoptosis by inhibiting the PI3K/AKT signalling pathway, suggesting that CAR can be used as new strategy for oesophageal cancer treatment.