Targeted therapies in metastatic esophageal cancer: advances over the past decade

Exploring metabolic reprogramming in esophageal cancer: the role of key enzymes in glucose, amino acid, and nucleotide pathways and targeted therapies

Esophageal cancer (EC) is one of the most common malignancies worldwide with the character of poor prognosis and high mortality. Despite significant advancements have been achieved in elucidating the molecular mechanisms of EC, for example, in the discovery of new biomarkers and metabolic pathways, effective treatment options for patients with advanced EC are still limited. Metabolic heterogeneity in EC is a critical factor contributing to poor clinical outcomes. This heterogeneity arises from the complex interplay between the tumor microenvironment and genetic factors of tumor cells, which drives significant metabolic alterations in EC, a process known as metabolic reprogramming. Understanding the mechanisms of metabolic reprogramming is essential for developing new antitumor therapies and improving treatment outcomes. Targeting the distinct metabolic alterations in EC could enable more precise and effective therapies. In this review, we explore the complex metabolic changes in glucose, amino acid, and nucleotide metabolism during the progression of EC, and how these changes drive unique nutritional demands in cancer cells. We also evaluate potential therapies targeting key metabolic enzymes and their clinical applicability. Our work will contribute to enhancing knowledge of metabolic reprogramming in EC and provide new insights and approaches for the clinical treatment of EC.

Impact of aspirin use on rates of metastasis in patients with esophageal cancer: insights from the National Inpatient Sample

Despite advancing treatment methods, esophageal cancer (EC) maintains a high mortality rate and poor prognosis. Through various mechanisms, aspirin has been suggested to have a chemopreventive effect on EC. However, the long-term impact, particularly regarding the rate of metastasis, needs to be further elucidated. NIS 2016-2020 was used to identify adult patients (age > 18 years) with EC using ICD-10 codes. Patients with missing demographics and mortality were excluded. Patients were stratified into two groups based on aspirin use. Data were collected on patient demographics, Elixhauser Comorbidity Index (ECI), and comorbidities (hypertension, chronic pulmonary disease, coronary artery disease (CAD), chronic kidney disease (CKD), congestive heart failure (CHF), coagulopathy, alcohol use, smoking, and obesity). The outcomes studied were rates of total metastasis, gastrointestinal (GI) metastasis, non-GI metastasis, and lymphoid metastasis. Multivariate logistic regression analysis was performed to evaluate the impact of aspirin use on various metastases after adjusting for patient demographics, comorbidities, and ECI. Out of 190,655 patients, 20,650 (10.8%) patients were aspirin users. Majority of the patients in the aspirin group were aged > 65 years (74.7%), males (82.1%), White race (84%), and had medicare insurance (71%). There was a higher incidence of diabetes, hypertension, chronic pulmonary disease, CAD, CKD, CHF, and smoking in aspirin users than non-aspirin users. Patients with aspirin users had a lower incidence of metastasis (28.9% vs. 38.7%, P < 0.001), GI metastasis (14.2% vs. 20.6%, P < 0.001), non-GI metastasis (15.1% vs. 22%, P < 0.001), and lymphoid metastasis (8.9% vs. 11.3%, P < 0.001) than non-aspirin users. After adjusting for confounding factors, patients with aspirin use had lower odds of having metastasis (aOR-0.73, 95% CI-0.70-0.77, P < 0.001). Our study noted that aspirin use is associated with a reduction in the rate of metastasis in patients with EC. These studies support the use of aspirin in patients with EC and suggest the need for further studies to understand the mechanism by which aspirin use reduces metastasis in patients with EC.

Oesophageal cancer metastases: An observational study of a more aggressive approach

BACKGROUND

The prognosis for oesophageal carcinoma is poor, but once distant metastases emerge the prognosis is considered hopeless. There is no consistent protocol for the early identification and aggressive management of metastases.

AIM

To examine the outcome of a policy of active postoperative surveillance with aggressive treatment of confirmed metastases.

METHODS

A prospectively maintained database of 205 patients diagnosed with oesophageal carcinoma between 1998 and 2019 and treated with curative intent was interrogated for patients with metastases, either at diagnosis or on follow-up surveillance and treated for cure. This cohort was compared with incomplete clinical responders to neoadjuvant chemoradiotherapy (nCRT) who subsequently underwent surgery on their primary tumour. Overall survival was estimated using the Kaplan-Meier method, and the log-rank test was used to compare survival differences between groups.

RESULTS

Of 205 patients, 11 (5.4%) had metastases treated for cure (82% male; median age 60 years; 9 adenocarcinoma and 2 squamous cell carcinomas). All had undergone neoadjuvant chemotherapy or chemoradiotherapy, followed by surgery in all but 1 case. Of the 11 patients, 4 had metastatic disease at diagnosis, of whom 3 were successfully downstaged with nCRT before definitive surgery; 2 of these 4 also developed oligometastatic recurrence and were treated with curative intent. Following definitive treatment, 7 had treatment for metachronous oligometastatic disease; 5 of whom underwent metastasectomy (adrenal × 2; lung × 2; liver × 1). The median overall survival was 10.9 years [95% confidence interval (CI): 0.7-21.0 years], which was statistically significantly longer than incomplete clinical responders undergoing surgery on the primary tumour without metastatic intervention [n = 62; median overall survival = 1.9 (95%CI: 1.1-2.7; P = 0.012]. The cumulative proportion surviving 1, 3, and 5 years was 100%, 91%, and 61%, respectively compared to 71%, 36%, and 25% for incomplete clinical responders undergoing surgery on the primary tumour who did not undergo treatment for metastatic disease.

CONCLUSION

Metastatic oesophageal cancer represents a unique challenge, but aggressive treatment can be rewarded with impressive survival data. In view of recent advances in targeted therapies, intensive follow-up may yield a greater number of patients with curative potential and thus improved long-term survival.

Fluoroscopy-Guided Salvage Photodynamic Therapy Combined with Nanoparticle Albumin-Bound Paclitaxel for Locally Advanced Esophageal Cancer after Chemoradiotherapy: A Case Report and Literature Review

Background: Among the total cancer deaths, esophageal cancer ranks sixth in mortality. Radiotherapy and chemotherapy remain the main treatments for unresectable, locally advanced esophageal cancer, but a relapse and drug resistance are still common. The optimized choice for therapeutic schemes with low toxicity and a high quality of life is unclear when local progression occurs after radiotherapy and chemotherapy. Fluoroscopy-guided photodynamic therapy (PDT) on patients with recurrent esophageal cancer in whom the endoscope cannot pass may be used as a salvage treatment, and nanoparticle albumin-bound paclitaxel (Nab-P) has been shown to be effective for advanced esophageal cancer. The combination of PDT and Nab-P might be an effective and tolerable option for advanced esophageal cancer. Case summary: The authors present a 65-year-old male patient diagnosed with esophageal squamous cell carcinoma (ESCC) and confirmed to have developed local progression after receiving radiotherapy and chemotherapy. Severe esophageal stenosis, mild malnutrition and anemia, and radiation pneumonia were found when he was admitted to the authors' hospital. For rapid reduction of tumor burden and to restore normal diet, he received PDT by the X-ray fluoroscopy positioning method and Nab-P chemotherapy. The patient obtained clinical benefit from these treatments, and his quality of life improved. Conclusions: This case demonstrates the potential advantages of fluoroscopy-guided PDT combined with Nab-P in reducing the tumor load, preserving organ function, and improving the quality of life, as well as the beneficial effect on locally advanced esophageal cancer after radiotherapy and chemotherapy. This combination therapy provides an alternative for the clinical treatment of locally advanced esophageal cancer and it has broad prospects in treatment of the disease. Core tip: Herein, the authors report a case of a patient with ESCC who suffered locally progressive disease after chemotherapy and radiotherapy as well as malnutrition and mild anemia because of feeding difficulties. The patient was treated with PDT, which was assisted by a new positioning technique of X-ray fluoroscopy and Nab-P chemotherapy, and finally achieved clinical benefits. In addition, a modified transnasal feeding tube was also applied in the process of fluoroscopy-guided PDT in this article.

SHCBP1 Promotes the Progression of Esophageal Squamous Cell Carcinoma Via the TGFβ Pathway

Esophageal cancer (EC) is known as a type of common malignant tumor, with the incidence ranking eighth worldwide. Because of the high metastasis of advanced EC, the total survival rate has been quite low. Esophageal squamous cell carcinoma (ESCC) is a main type of EC. Targeted therapy for ESCC has become a new direction; however, newly therapeutic targets are also badly needed. Shc SH2 domain-binding protein (SHCBP1) is located on 16q11.2, which is a downstream protein of the Shc adaptor. SHCBP1 participates in the regulation of several physiological and pathologic processes, such as cytokinesis. Recent studies have found that SHCBP1 was abnormally upregulated in multiple types of tumors, such as breast cancer and liver cancer, and that it affects the proliferation and motility of cancer cells in vitro. However, it remains unclear whether SHCBP1 is related to the progression of EC. Herein, we found the upregulation of SHCBP1 in human EC tissues. Our findings further demonstrated that SHCBP1 expression was related to the clinical features of ESCC patients. We found that SHCBP1 depletion inhibited the proliferation and motility of ESCC cells via the transforming growth factor β pathway and that it suppressed the growth of tumors in mice. We, therefore, concluded that SHCBP1 could serve as a promising EC molecular target.

Omipalisib Inhibits Esophageal Squamous Cell Carcinoma Growth Through Inactivation of Phosphoinositide 3-Kinase (PI3K)/AKT/Mammalian Target of Rapamycin (mTOR) and ERK Signaling

Background

Esophageal squamous cell carcinoma (ESCC) is a life-threatening digestive tract malignancy with no known curative treatment. This study aimed to investigate the antineoplastic effects of omipalisib and its underlying molecular mechanisms in ESCC using a high throughput screen.

Material/Methods

MTT assay and clone formation were used to determine cell viability and proliferation. Flow cytometry was conducted to detect cell cycle distribution and apoptosis. Global gene expression and mRNA expression levels were determined by RNA sequencing and real-time PCR, respectively. Protein expression was evaluated in the 4 ESCC cell lines by Western blot analysis. Finally, a xenograft nude mouse model was used to evaluate the effect of omipalisib on tumor growth in vivo.

Results

In the pilot screening of a 1404-compound library, we demonstrated that omipalisib markedly inhibited cell proliferation in a panel of ESCC cell lines. Mechanistically, omipalisib induced G₀/G₁ cell cycle arrest and apoptosis. RNA-seq, KEGG, and GSEA analyses revealed that the PI3K/AKT/mTOR pathway is the prominent target of omipalisib in ESCC cells. Treatment with omipalisib decreased expression of p-AKT, p-4EBP1, p-p70S6K, p-S6, and p-ERK, therefore disrupting the activation of PI3K/AKT/mTOR and ERK signaling. In the nude mouse xenograft model, omipalisib significantly suppressed the tumor growth in ESCC tumor-bearing mice without obvious adverse effects.

Conclusions

Omipalisib inhibited the proliferation and growth of ESCC by disrupting PI3K/AKT/mTOR and ERK signaling. The present study supports the rationale for using omipalisib as a therapeutic approach in ESCC patients. Further clinical studies are needed.

Knockdown of FAM83D Enhances Radiosensitivity in Coordination with Irradiation by Inhibiting EMT via the Akt/GSK-3β/Snail Signaling Pathway in Human Esophageal Cancer Cells

Purpose

To explore the effects of FAM83D on the proliferation, invasion and radiosensitivity of human esophageal cancer cells and to elucidate the mechanism involved in the regulation of the growth and metastasis of esophageal cancer cells.

Methods and Materials

This study included sixty-nine patients with esophageal cancer. The expression levels of FAM83D in the esophageal cancer tissues and paracarcinoma tissues of the sixty-nine patients were measured. We also examined FAM83D expression in five cell lines. We analyzed the effects of FAM83D on the proliferation, invasion and radiosensitivity of human esophageal cancer cells via MTS, Transwell, and colony formation assays. The effect of FAM83D knockdown on cell apoptosis was assayed by flow cytometry. In addition, we also examined changes in the expression of metastasis-related molecules at the protein and mRNA levels by qRT-PCR and Western blotting after silencing FAM83D expression, and we detected the expression of PI3K/Akt signaling-related proteins by Western blotting.

Results

The results demonstrated that the expression of FAM83D was obviously higher in esophageal cancer tissues and cell lines than that in human adjacent normal tissues and normal esophageal epithelial cell lines. FAM83D overexpression was positively associated with tumor size, tumor-node-metastasis (TNM) stage, T classification, N classification, distant metastasis and relapse and was negatively associated with patient survival rates. FAM83D shRNA transfection suppressed its expression. Compared to that in the control group, the proliferation of tumor cells in the FAM83D shRNA group was hindered after exposure to radiation in vitro and in vivo; in addition, FAM83D knockdown inhibited cell invasion, induced apoptosis and regulated apoptosis-related protein expression. Moreover, the radiosensitivity of esophageal cancer cells was increased after depletion of FAM83D. In addition, FAM83D silencing was associated with the reversion of EMT, as reflected by an increase in the epithelial marker E-cadherin and a decrease in the mesenchymal markers N-cadherin and vimentin. Further study showed that FAM83D depletion suppressed the signaling pathway involving p-Akt, p-GSK-3β and Snail.

Conclusion

The results reveal that FAM83D may be a potential therapeutic target for esophageal squamous cell carcinoma (ESCC) and that lower expression of FAM83D in coordination with irradiation promotes the radiosensitization of ESCC by inducing EMT through the Akt/GSK-3β/Snail signaling pathway.

Cabozantinib (XL184) and R428 (BGB324) Inhibit the Growth of Esophageal Squamous Cell Carcinoma (ESCC)

Esophageal squamous cell carcinoma (ESCC) is a deadly disease for which no effective targeted therapeutic agent has been approved. Both AXL and c-MET have been reported to be independent prognostic factors for ESCC. Thus, inhibitors of AXL/c-MET might have great potential as targeted therapy for ESCC. In the current study, we evaluated the therapeutic potential of the AXL/c-MET selective inhibitors, R428 and cabozantinib, in cell and mouse xenograft models. We demonstrated that both R428 and cabozantinib significantly inhibited the growth of CE81T and KYSE-70 ESCC cells and showed by wound-healing assay that they both inhibited ESCC cell migration. In the animal model, ESCC xenograft models were established by injecting KYSE-70 cells with Matrigel into the upper back region of NOD-SCID male mice followed by treatment with vehicle control, R428 (50 mg/kg/day), cisplatin (1.0 mg/kg), or cabozantinib (30 mg/kg/day) for the indicated number of days. R428 alone significantly inhibited ESCC tumor growth compared to the vehicle; however, no synergistic effect with cisplatin was observed. Notably, the dramatic efficacy of cabozantinib alone was observed in the mouse xenograft model. Collectively, our study demonstrated that both cabozantinib and R428 inhibit ESCC growth in cell and xenograft models. The results reveal the great potential of using cabozantinib for targeted therapy of ESCC.

Impact of sequential lines of palliative chemotherapy in patients with recurrent/metastatic esophageal squamous cell carcinoma: A retrospective analysis of 107 patients at a single center

AIM

This study was conducted to evaluate the efficacy of palliative chemotherapy by the lines of chemotherapy in recurrent/metastatic esophageal squamous cell carcinoma (ESCC) and to compare the efficacy between the patients with initially metastatic ESCC and those with recurrent/progressed ESCC after curative treatment.

MATERIALS AND METHODS

All 107 patients who began palliative chemotherapy for recurrent/metastatic ESCC from March 2015 to October 2017 were included, and grouped according to previous treatment: Groups A (previous chemoradiation alone, n = 30), B (previous surgery alone, n = 11), C (previous chemoradiation and surgery, n = 30), and D (initially metastatic or de novo stage IV, n = 36). Groups A, B, and C (pretreated group) and Group D (treatment-naïve group) were reorganized according to treatment history. Overall response rate (ORR) and survival data were retrospectively evaluated for each group, lines of chemotherapy, and chemotherapeutic regimen.

RESULTS

ORR was 25.2%, 7.3%, and 3.4% in first-, second-, and third-line chemotherapy, respectively. The median progression-free survival (PFS) was 4.7, 2.0, and 2.2 months in first-, second-, third-line chemotherapy, respectively. The median overall survival (OS) after first-line palliative chemotherapy was 10.1 months, and it was not significantly different between pretreated and treatment-naive groups. Previous surgery, good performance, ≥3 lines of chemotherapy, and low C-reactive protein level were linked to a significantly longer OS in multivariate analysis.

CONCLUSION

Because PFS rapidly declines with advancement of line of chemotherapy, incorporation of effective treatment modalities in early line treatments is crucial in the management of recurrent/metastatic ESCC. If tolerable, continuing advanced lines of chemotherapy may prolong survival.

Tetrahydrocurcumin, Curcumin, and 5-Fluorouracil Effects on Human Esophageal Carcinoma Cells

Background:

Esophageal cancer responds poorly to traditional therapies, and novel treatments are needed. The phytochemical curcumin is a potential treatment for Esophageal Squamous Cell Carcinoma (ESCC). A curcumin metabolite, tetrahydrocurcumin (THCUR), has anti-cancer effects and greater bioavailability than curcumin.

Objective:

Evaluate THCUR as an anti-cancer agent relative to curcumin and a standard cancer drug, 5-fluorouracil (5-FU), along with treatment interactions.

Materials and Methods:

Assay cell proliferation and viability following individual and combined delivery of the compounds to three ESSC cell lines (TE-1, TE-8, and KY-5) that have different percentages of Cancer Stem Cells (CSCs).

Results:

Curcumin was significantly more effective than 5-FU in all three cell lines. It also had the greatest effect on KY-5 cells, which have the highest CSC properties, consistent with the ability of curcumin to target CSCs. Effects on ESCC cell proliferation were not detected from 40µM THCUR, a dosage above the IC50 of curcumin and 5-FU. However, THCUR at this dosage in combination with 5-FU significantly suppressed TE-1 cell proliferation, but 5-FU alone did not. As TE-1 has low CSC properties relative to the two other cell lines, it was expected to have the least resistance to chemotherapeutic treatments. Surprisingly, TE-1 was the most resistant to inhibition by 5-FU.

Conclusion:

These results and the greater stability and water solubility of THCUR than curcumin support further testing of THCUR in combination with standard treatments, particularly for chemoresistant ESCC. In contrast to concerns that curcuminoids taken by patients through diet or diet supplements might interfere with chemotherapy, suppression of 5-FU efficacy by curcumin was not observed.

Multiple modulatory activities of Andrographis paniculata on immune responses and xenograft growth in esophageal cancer preclinical models

BACKGROUND

Esophageal cancer (EC) is a malignant gastrointestinal cancer with high morbidity worldwide and is the fourth leading cause of cancer-related deaths in China. Even though surgery and/or chemotherapy/chemoradiation might achieve good therapeutic response, recurrence rate is high due to cancer metastasis. Hence, the use of alternative adjuvant treatments, such as herbal medicines, for metastatic EC remains a great desire of the patients. Our previous studies have demonstrated the anti-metastatic efficacy of hot water extract of Andrographis paniculata (APW) in human esophageal cancer cells and tumor-bearing nude mice.

PURPOSE

In the present study, the immunomodulatory activities of APW were further evaluated in human peripheral blood mononuclear cells (PBMCs) and in a carcinogen-induced esophageal tumorigenesis model using immune-competent C57BL/6 mice. Besides, the inhibitory effects of APW on esophageal cancer cell line-based xenografts and patient-derived xenografts (PDX) were examined so as to illustrate the potential multi-targeted efficacies of APW in esophageal cancer in pre-clinical models.

RESULTS

In vitro results showed that APW could stimulate proliferation of PBMCs, as well as TNF-α and IFN-γproductions. In mice with 4-nitroquinoline 1-oxide-induced tumorigenesis, 21-day oral treatment with APW (1600 mg/kg) decreased the level of dysplasia in esophagus and significantly modulated the population of regulatory T cells. The cytokines productions by spleen lymphocytes of APW-treated mice were shifted towards normal resting state (i.e. unchallenged with carcinogen). Furthermore, APW treatment suppressed the growth of cell line-based xenografts by significantly increasing apoptosis in tumors, without causing severe body weight loss as chemotherapeutics did. Most importantly, the inhibitory effects of APW treatment on esophageal patient-derived xenografts growth were demonstrated for the first time. Besides, several diterpenes were detected in the plasma after oral administration of APW in mice, suggesting that multi-components of APW were bioavailable and might have contributed towards the varied pharmacological activities demonstrated in our studies.

CONCLUSION

APW was shown to possess anti-tumor, anti-metastatic and immunomodulatory activities in esophageal cancer cell-based and animal models, including immunocompromised mice model and clinically relevant PDX model. Our findings illustrated the potential multi-targeted efficacies of APW in esophageal cancer management.

FAM3B promotes progression of oesophageal carcinoma via regulating the AKT-MDM2-p53 signalling axis and the epithelial-mesenchymal transition

FAM3B has been suggested to play important roles in the progression of many cancers, such as gastric, oral, colon and prostate cancer. However, little is known about the role of FAM3B in human esophageal squamous cell carcinoma (ESCC). In the present study, we found that FAM3B expression was higher in ESCC tissues than in adjacent normal tissues. Using quantitative real-time polymerase chain reaction, we found similar results in cell lines. FAM3B expression was significantly related to T/TNM stage. Importantly, Kaplan-Meier analysis revealed that a high expression level of FAM3B predicted a poor outcome for ESCC patients. Overexpression of FAM3B inhibits ESCC cell death, increases oesophageal tumour growth in xenografted nude mice, and promotes ESCC cell migration and invasion. Further studies confirmed that FAM3B regulates the AKT-MDM2-p53 pathway and two core epithelial-to-mesenchymal transition process markers, Snail and E-cadherin. Our results provide new insights into the role of FAM3B in the progression of ESCC and suggest that FAM3B may be a promising molecular target and diagnostic marker for ESCC.

miR-1 suppresses the proliferation and promotes the apoptosis of esophageal carcinoma cells by targeting Src

Nonreceptor tyrosine kinase c-Src, also known as Src, is a potent oncogene involved in a series of biological processes including cell growth, differentiation, and apoptosis; however, its expression pattern and function in esophageal cancer is poorly addressed. In this study, abnormal overexpression of Src protein was observed in esophageal cancer tissues, which fuelled the speculation that microRNA-mediated posttranscriptional regulatory mechanism might be involved. Bioinformatic analyses were applied to identify miRNAs that could potentially target Src. miR-1 was predicted and further validated as a direct repressor of Src. Moreover, we manipulated knockdown and overexpression experiment on TE-1 and TE-10 cells to demonstrate miR-1 suppressed proliferation and promoted apoptosis in esophageal cancer cells by inhibiting Src. Taken together, this study underlines a negative regulatory mechanism in which miR-1 serves as a suppressor of Src in esophageal cancer cells and may provide insights into novel therapeutic approaches for esophageal cancer.

GOLPH3 promotes cell proliferation and tumorigenicity in esophageal squamous cell carcinoma via mTOR and Wnt/β‑catenin signal activation

The authors' previous study demonstrated that Golgi phosphoprotein 3 (GOLPH3) was significantly overexpressed in esophageal squamous cell carcinoma (ESCC), correlating with poor patient survival. In the present study, GOLPH3 stable overexpression and knockdown KYSE‑140 cell lines were constructed. Cell proliferation, colony formation, cell cycle progression and tumorigenesis assays were performed. The results revealed that GOLPH3 promoted ESCC cell growth and proliferation. The effects of GOLPH3 on the mechanistic target of rapamycin (mTOR) and Wnt/β‑catenin signaling pathways were investigated using western blot analyis and dual‑luciferase reporter assays, and were observed to be activated in cells with GOLPH3 overexpression. Furthermore, overexpression of GOLPH3 resulted in the downregulation of p21 protein, upregulation of cyclin D1 and increased retinoblastoma‑associated protein phosphorylation, consequently leading to accelerated cell cycle progression. In addition, GOLPH3 knockdown resulted in reversed effects. The results of the current study suggest that GOLPH3 serves an important role in promoting tumorigenicity of ESCC via mTOR and Wnt/β‑catenin signaling pathway activation.

Delivery of a chemotherapeutic drug using novel hollow carbon spheres for esophageal cancer treatment

Low toxicity and high efficacy are the key factors influencing the real-world clinical applications of nanomaterial-assisted drug delivery. In this study, novel hollow carbon spheres (HCSs) with narrow size distribution were developed. In addition to demonstrating their ease of synthesis for large-scale production, we also demonstrated in vitro that the HCSs possessed high drug-loading capacity, lower cell toxicity, and optimal drug release profile at low pH, similar to the pH in the tumor microenvironment. The HCSs also displayed excellent immunocompatibility and could rapidly distribute themselves in the cytoplasm to escape lysosomal clearance. More importantly, the HCSs could efficiently deliver doxorubicin (a representative chemotherapeutic drug) to tumor sites, which resulted in significant inhibition of tumor growth in an esophageal xenograft cancer model. This also prolonged the circulation time and altered the biodistribution of the drug. In conclusion, this study revealed a novel drug delivery system for targeted tumor therapy.

Distinct effects of EGFR inhibitors on epithelial- and mesenchymal-like esophageal squamous cell carcinoma cells

Background

Epidermal growth factor receptor (EGFR) plays a pivotal role in the pathophysiology of esophageal squamous cell carcinoma (ESCC). However, the clinical effects of EGFR inhibitors on ESCC are controversial. This study sought to identify the factors determining the therapeutic efficacy of EGFR inhibitors in ESCC cells.

Methods

Immortalized-human esophageal epithelial cells (EPC2-hTERT), transformed-human esophageal epithelial cells (T-Epi and T-Mes), and ESCC cells (TE-1, TE-5, TE-8, TE-11, TE-11R, and HCE4) were treated with the EGFR inhibitors erlotinib or cetuximab. Inhibitory effects on cell growth were assessed by cell counting or cell-cycle analysis. The expression levels of genes and proteins such as involucrin and cytokeratin13 (a squamous differentiation marker), E-cadherin, and vimentin were evaluated by real-time polymerase chain reaction or western blotting. To examine whether mesenchymal phenotype influenced the effects of EGFR inhibitors, we treated T-Epi cells with TGF-β1 to establish a mesenchymal phenotype (mesenchymal T-Epi cells). We then compared the effects of EGFR inhibitors on parental T-Epi cells and mesenchymal T-Epi cells. TE-8 (mesenchymal-like ESCC cells)- or TE-11R (epithelial-like ESCC cells)-derived xenograft tumors in mice were treated with cetuximab, and the antitumor effects of EGFR inhibitors were evaluated.

Results

Cells were classified as epithelial-like or mesenchymal-like phenotypes, determined by the expression levels of E-cadherin and vimentin. Both erlotinib and cetuximab reduced cell growth and the ratio of cells in cell-cycle S phase in epithelial-like but not mesenchymal-like cells. Additionally, EGFR inhibitors induced squamous cell differentiation (defined as increased expression of involucrin and cytokeratin13) in epithelial-like but not mesenchymal-like cells. We found that EGFR inhibitors did not suppress the phosphorylation of EGFR in mesenchymal-like cells, while EGFR dephosphorylation was observed after treatment with EGFR inhibitors in epithelial-like cells. Furthermore, mesenchymal T-Epi cells showed resistance to EGFR inhibitors by circumventing the dephosphorylation of EGFR signaling. Cetuximab consistently showed antitumor effects, and increased involucrin expression in TE-11R (epithelial-like)-derived xenograft tumors but not TE-8 (mesenchymal-like)-derived xenograft tumors.

Conclusions

The factor determining the therapeutic effects of EGFR inhibitors in ESCC cells is the phenotype representing the epithelial-like or mesenchymal-like cells. Mesenchymal-like ESCC cells are resistant to EGFR inhibitors because EGFR signaling is not blocked. EGFR inhibitors show antitumor effects on epithelial-like ESCC cells accompanied by promotion of squamous cell differentiation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0572-7) contains supplementary material, which is available to authorized users.

Single molecule force spectroscopy for in-situ probing oridonin inhibited ROS-mediated EGF-EGFR interactions in living KYSE-150 cells

As the active anticancer component of Rabdosia Rubescens, oridonin has been proved to show strong anticancer activity in cancer cells, which is also found to be closely related to its specific inhibition effects on the EGFR tyrosine kinase activity. In this study, atomic force microscopy based single molecule force spectroscopy (AFM-SMFS) was used for real-time and in-situ detection of EGF-EGFR interactions in living esophageal cancer KYSE-150 cells to evaluate the anticancer activity of oridonin for the first time. Oridonin was found to induce apoptosis and also reduce EGFR expression in KYSE-150 cells. AFM-SMFS results demonstrated that oridonin could inhibit the binding between EGF and EGFR in KYSE-150 cells by decreasing the unbinding force and binding probability for EGF-EGFR complexes, which was further proved to be closely associated with the intracellular ROS level. More precise mechanism studies based on AFM-SMFS demonstrated that oridonin treatment could decrease the energy barrier width, increase the dissociation off rate constant and decrease the activation energy of EGF-EGFR complexes in ROS dependent way, suggesting oridonin as a strong anticancer agent targeting EGF-EGFR interactions in cancer cells through ROS dependent mechanism. Our results not only suggested oridonin as a strong anticancer agent targeting EGF-EGFR interactions in ROS dependent mechanism, but also highlighted AFM-SMFS as a powerful technique for pharmacodynamic studies by detecting ligand-receptor interactions, which was also expected to be developed into a promising tool for the screening and mechanism studies of drugs.

The mechanisms of radioresistance in esophageal squamous cell carcinoma and current strategies in radiosensitivity

Esophageal cancer is the eighth most common cancer and the sixth leading cause of cancer-related death worldwide. Surgery is the primary form of treatment, but the survival is poor, especially for patients with locally advanced esophageal cancer. Radiotherapy has been a critical treatment option that may be combined with chemotherapy in patients with unresectable esophageal cancer. However, resistance to chemoradiotherapy might result in treatment failures and cancer relapse. This review will mainly focus on the possible cellular mechanisms and tumor-associated microenvironmental (TAM) factors that result in radioresistance in patients with esophageal cancer. In addition, current strategies to increase radiosensitivity, including targeted therapy and the use of radiosensitive biomarkers in clinical treatment, are discussed in this review.

Vascular endothelial growth factor-targeted paclitaxel-loaded liposome microbubbles and inhibition of human epidermoid-2 cell proliferation

BACKGROUND

Vascular endothelial growth factor (VEGF) plays an important role in the formation of capillary blood vessels. The purpose of this study was to evaluate the inhibitory effect of VEGF-targeted paclitaxel (PTX)-loaded liposome microbubbles (VTPLLMs) on the proliferation of human epidermoid (Hep-2) laryngeal squamous cell carcinoma (SCC).

METHODS

Six groups were randomly divided. The inhibitory effects on Hep-2 proliferation were assessed by a methylthiazol tetrazolium (MTT) method. The cell cycle distributions were investigated by flow cytometry. The expression variations of VEGF and caspase-3 were compared by Western blotting.

RESULTS

Proliferation of Hep-2 in the VTPLLM+ultrasound group was significantly inhibited, and flow cytometry showed that the Hep-2 cells were significantly blocked at stage G2/M compared with other groups. Moreover, Western blotting showed VEGF expression was downregulated and caspase-3 expression was upregulated.

CONCLUSION

VTPLLMs can efficiently inhibit tumor cell proliferation and outperform nontargeted microbubbles or PTX. © 2017 Wiley Periodicals, Inc. Head Neck 39: 656-661, 2017.

Transcriptional regulation by normal epithelium of premalignant to malignant progression in Barrett's esophagus

In carcinogenesis, intercellular interactions within and between cell types are critical but remain poorly understood. We present a study on intercellular interactions between normal and premalignant epithelial cells and their functional relevance in the context of premalignant to malignant progression in Barrett's esophagus. Using whole transcriptome profiling we found that in the presence of normal epithelial cells, dysplastic cells but not normal cells, exhibit marked down-regulation of a number of key signaling pathways, including the transforming growth factor beta (TGFβ) and epithelial growth factor (EGF). Functional assays revealed both cell types showed repressed proliferation and significant changes in motility (speed, displacement and directionality) as a result of interactions between the two cell types. Cellular interactions appear to be mediated through both direct cell-cell contact and secreted ligands. The findings of this study are important in that they reveal, for the first time, the effects of cellular communication on gene expression and cellular function between premalignant (dysplastic) epithelial cells and their normal counterparts.

TIM-3 promotes the metastasis of esophageal squamous cell carcinoma by targeting epithelial-mesenchymal transition via the Akt/GSK-3β/Snail signaling pathway

T-cell immunoglobulin and mucin domain-con-taining protein-3 (TIM-3), a negative regulator of antitumor immune response, has been demonstrated to be involved in the onset and progression of several types of malignancies. The present study aimed to determine whether and how TIM‑3 plays such a role in esophageal squamous cell carcinoma (ESCC). TIM-3 expression was analyzed by immunohistochemistry and real‑time fluorescence quantitative PCR (qRT‑PCR) in ESCC and matched adjacent normal tissues. Functional experiments in vitro were performed to elucidate the effect of TIM‑3 knockdown on the proliferation, apoptosis, migration, invasion and epithelial-mesenchymal transition (EMT) in Eca109 and TE‑1 cell lines. Our data revealed that TIM‑3 expression was significantly elevated at both the mRNA and protein levels in ESCC tissues compared with the levels in the matched adjacent normal tissues (both P<0.001). TIM‑3 expression was significantly associated with lymph node metastasis (P=0.008), tumor‑node‑metastasis (TNM) stage (P=0.042) and depth of tumor invasion (P=0.042). In addition, we observed a strong correlation between high TIM‑3 expression and a worse overall survival of ESCC patients (P=0.001). Functional study demonstrated that TIM‑3 knockdown markedly inhibited proliferation, migration and invasion of ESCC cell lines without affecting apoptosis. In addition, TIM‑3 depletion was associated with downregulation of matrix metalloproteinase (MMP)-9 and upregulation of tissue inhibitor of metalloproteinase (TIMP)-1, and with reversion of EMT, as reflected by higher levels of the epithelial marker E‑cadherin and lower levels of the mesenchymal markers N‑cadherin and vimentin. Further study found that TIM‑3 depletion suppressed the signaling pathway involving p‑Akt, p‑GSK‑3β and Snail. Taken together, these results suggest that TIM‑3 is a novel therapeutic target and prognostic biomarker for ESCC and promotes metastasis of ESCC by inducing EMT via, at least partially, the Akt/GSK-3β/Snail signaling pathway.

The Prognostic Impact of Heat Shock Proteins Expression in Patients with Esophageal Cancer: A Meta-Analysis

PURPOSE

Heat shock proteins (HSPs) are highly conserved molecular chaperones. There are various studies that assess the prognostic value of HSPs in patients with esophageal cancer, but the conclusion remains controversial. This is the first meta-analysis study aiming to summarize the evidence on the suitability of HSPs to predict patients' survival.

MATERIALS AND METHODS

Searching PubMed, Web of science and Medline until May 31, 2014, data were compared for overall survival in patients with down-regulated HSPs level with those with up-regulated level. We conducted a meta-analysis of 9 studies (801 patients) that correlated HSPs levels with overall survival. Data were synthesized with hazard ratios (HRs).

RESULTS

The estimated risk of death was 2.93-fold greater in HSP27 negative patients than HSP27 positive patients [95% confidence interval (CI), 1.12-7.62]. When limited to esophageal squamous cell carcinoma (ESCC), the risk of death in HSP27 negative patients seemed more significant (HR, 3.90; 95% CI, 2.35-6.49). Decreased expression of HSP70 was also associated with worse survival in esophageal cancer (HR, 2.83; 95% CI, 1.90-4.23) and, when limited to ESCC, HR was 3.21 (95% CI, 1.94-5.30). Data collected, however, were not sufficient to determine the prognostic value of HSP90 in patients with ESCC nor esophageal adenocarcinomas (EADC).

CONCLUSION

In this meta-analysis, reduced HSP27 and HSP70 expressions were associated with poor survival in patients with esophageal cancer, especially esophageal squamous cell carcinoma.

Correlation between vascular endothelial growth factor expression and presence of lymph node metastasis in advanced squamous cell carcinoma of the larynx

INTRODUCTION

Squamous cell carcinoma is the most common neoplasm of the larynx, and its evolution depends on tumor staging. Vascular endothelial growth factor is a marker of angiogenesis, and its expression may be related to increased tumor aggressiveness, as evidenced by the presence of cervical lymphatic metastases.

OBJECTIVES

To evaluate the expression of the vascular endothelial growth factor marker in non-glottic advanced squamous cell carcinoma of the larynx (T3/T4) and correlate it with the presence of cervical lymph node metastases.

METHODS

Retrospective clinical study and immunohistochemical analysis of vascular endothelial growth factor through the German scale of immunoreactivity in products of non-glottic squamous cell carcinomas.

RESULTS

This study analyzed 15 cases of advanced non-glottic laryngeal tumors (T3/T4), four of which exhibited cervical lymphatic metastases. There was no correlation between vascular endothelial growth factor expression and the presence of cervical metastases.

CONCLUSION

Although vascular endothelial growth factor was expressed in a few cases, there was no correlation with the spread of cervical lymph metastases.

Molecular markers and imaging tools to identify malignant potential in Barrett's esophagus

Due to its rapidly rising incidence and high mortality, esophageal adenocarcinoma is a major public health concern, particularly in Western countries. The steps involved in the progression from its predisposing condition, gastroesophageal reflux disease, to its premalignant disorder, Barrett’s esophagus, and to cancer, are incompletely understood. Current screening and surveillance methods are limited by the lack of population-wide utility, incomplete sampling of standard biopsies, and subjectivity of evaluation. Advances in endoscopic ablation have raised the hope of effective therapy for eradication of high-risk Barrett’s lesions, but improvements are needed in determining when to apply this treatment and how to follow patients clinically. Researchers have evaluated numerous potential molecular biomarkers with the goal of detecting dysplasia, with varying degrees of success. The combination of biomarker panels with epidemiologic risk factors to yield clinical risk scoring systems is promising. New approaches to sample tissue may also be combined with these biomarkers for less invasive screening and surveillance. The development of novel endoscopic imaging tools in recent years has the potential to markedly improve detection of small foci of dysplasia in vivo. Current and future efforts will aim to determine the combination of markers and imaging modalities that will most effectively improve the rate of early detection of high-risk lesions in Barrett’s esophagus.

SMG1 acts as a novel potential tumor suppressor with epigenetic inactivation in acute myeloid leukemia

Suppressor with morphogenetic effect on genitalia family member (SMG1) belongs to a family of phosphoinositide 3-kinase-related kinases and is the main kinase involved in nonsense-mediated mRNA decay. Recently, SMG1 was suggested as a novel potential tumor suppressor gene, particularly in hypoxic tumors. To investigate the function of SMG1 in acute myeloid leukemia (AML), we performed methylation-specific polymerase chain reaction and found that SMG1 was hypermethylated in the promoter region. SMG1 hypermethylation was found in 66% (33/50) of AML samples compared with none (0/14) of the normal controls. SMG1 mRNA was down-regulated in AML patients with hypermethylation status whereas it was readily expressed in patients without methylation. Moreover, treatment of AML cells with demethylating agent 5-aza-2'-deoxycytidine (decitabine) inhibited AML cell growth and induced apoptosis by reversing SMG1 methylation status and restoring SMG1 expression. On the other hand, knockdown of SMG1 by RNA interference inhibited apoptosis. We also found that mTOR expression level was negatively correlated to SMG1 expression in AML patients which indicated that SMG1 and mTOR maybe act antagonistically to regulate AML cell growth. In conclusion, our results indicate that SMG1 acts as a potential tumor suppressor with epigenetic regulation in AML.

The 4E-BP1/eIF4E ratio is a determinant for rapamycin response in esophageal cancer cells

OBJECTIVES

Rapamycin inhibits products of molecular pathways in esophageal squamous cell carcinoma and limits tumor cell growth by targeting 4E-BP1- and eIF4E-dependent gene translation. In this study, we investigate the influence of 4E-BP1-to-eIF4E ratio on rapamycin response in esophageal squamous cell carcinoma cells, and the underlying mechanism is discussed.

METHODS

The response to rapamycin treatment was examined in 6 esophageal cancer cell lines. Adjustment of the 4E-BP1/eIF4E ratio was carried out by knockdown or overexpression of 4E-BP1 and eIF4E. The relationship between Egr-1 and 4E-BP1 expression in esophageal cancer cells was also studied.

RESULTS

The 4E-BP1/eIF4E ratio was adjusted to evaluate the response to rapamycin treatment in TE1 and TE2 esophageal cancer cells. TE2 cells are sensitized to rapamycin treatment after overexpression of 4E-BP1 or knockdown of eIF4E; TE1 cells become resistant to rapamycin after knockdown of 4E-BP1 or overexpression of eIF4E. These data suggest that the 4E-BP1/eIF4E ratio is a determinant for the response of TE1 and TE2 cells to rapamycin treatment. Egr-1 expression was higher in TE2 cells compared with other esophageal cancer cell lines, and its knockdown increased 4E-BP1 expression in TE2 cells, which became sensitive to rapamycin treatment.

CONCLUSIONS

The 4E-BP1/eIF4E ratio is a determinant of the response of rapamycin treatment in esophageal cancer cells. Egr-1 can reduce 4E-BP1 gene expression and render esophageal squamous cell carcinoma cells resistant to rapamycin with a relatively low 4E-BP1/eIF4E ratio. Thus, the 4E-BP1/eIF4E ratio may represent a therapeutic index for the prediction of clinical outcome of rapamycin treatment in patients with esophageal squamous cell carcinoma.