Chemoradiation in oesophageal cancer

Predicting the HER2 status in oesophageal cancer from tissue microarrays using convolutional neural networks

BACKGROUND

Fast and accurate diagnostics are key for personalised medicine. Particularly in cancer, precise diagnosis is a prerequisite for targeted therapies, which can prolong lives. In this work, we focus on the automatic identification of gastroesophageal adenocarcinoma (GEA) patients that qualify for a personalised therapy targeting epidermal growth factor receptor 2 (HER2). We present a deep-learning method for scoring microscopy images of GEA for the presence of HER2 overexpression.

METHODS

Our method is based on convolutional neural networks (CNNs) trained on a rich dataset of 1602 patient samples and tested on an independent set of 307 patient samples. We additionally verified the CNN's generalisation capabilities with an independent dataset with 653 samples from a separate clinical centre. We incorporated an attention mechanism in the network architecture to identify the tissue regions, which are important for the prediction outcome. Our solution allows for direct automated detection of HER2 in immunohistochemistry-stained tissue slides without the need for manual assessment and additional costly in situ hybridisation (ISH) tests.

RESULTS

We show accuracy of 0.94, precision of 0.97, and recall of 0.95. Importantly, our approach offers accurate predictions in cases that pathologists cannot resolve and that require additional ISH testing. We confirmed our findings in an independent dataset collected in a different clinical centre. The attention-based CNN exploits morphological information in microscopy images and is superior to a predictive model based on the staining intensity only.

CONCLUSIONS

We demonstrate that our approach not only automates an important diagnostic process for GEA patients but also paves the way for the discovery of new morphological features that were previously unknown for GEA pathology.

SOX17-mediated MALAT1-miR-199a-HIF1α axis confers sensitivity in esophageal squamous cell carcinoma cells to radiotherapy

Radiotherapy is a main modality of esophageal squamous cell carcinoma (ESCC) treatment, while radioresistance largely limits the effect of this therapy. Evidence exists reporting that SOX17 may sensitize ESCC cells to irradiation, but the downstream mechanism remains poorly understood. Therefore, we attempt to explore the molecular basis of SOX17 effect on radioresistance in ESCC. The SOX17 expression was measured in ESCC tissues and cells, followed by evaluation of its relationship with patient survival. The fractionated irradiation-induced irradiation-resistant cell line KYSE150R was subjected to gain- and loss-of function studies to explore the effect of SOX17 and downstream effectors MALAT1, miR-199a, and HIF1α on the malignant phenotypes of ESCC. The interaction among these factors was explained using ChIP, dual luciferase reporter, RNA pull-down and RIP assays. Further, the in vivo effect of SOX17 on ESCC irradiation tolerance was assessed in nude mice. SOX17 was underexpressed in ESCC tissues and cells, which was negatively correlated with the prognosis of patients with ESCC. Besides, SOX17 inhibited irradiation tolerance of ESCC cells by suppressing MALAT1 transcription. Notably, MALAT1 acted as miR-199a sponge and thereby enhanced HIF1α expression. Moreover, SOX17 reduced the irradiation tolerance of ESCC cells by reducing HIF1α expression via the MALAT1-miR-199a axis, and attenuated tumor formation in nude mice. Our results indicate that SOX17 can impede the radioresistance of ESCC cells through the MALAT1-miR-199a-HIF1α axis, in support of further research for ESCC radiotherapy.

CDCA2 promotes tumorigenesis and induces radioresistance in oesophageal squamous cell carcinoma cells

Cell division cycle‑associated 2 (CDCA2) overexpression has been demonstrated to serve a significant role in tumorigenesis in certain types of cancer. Nevertheless, its role in tumour proliferation and radioresistance in oesophageal squamous cell carcinoma (ESCC) remains to be elucidated. Thus, the present study aimed to elucidate these roles. Data were downloaded from The Cancer Genome Atlas (TCGA) to compare the gene expression profiles. The expression of CDCA2 was higher in ESCC tissues compared with normal tissues. Gene set enrichment analysis was performed based on the ESCC cohorts in TCGA database. This demonstrated that higher expression of CDCA2 was significantly associated with the expression of related components of the cell cycle phase transition and G2/M phase transition pathways. Collectively, the results revealed that CDCA2 could serve as an underlying target to regulate tumour growth and radioresistance among patients with ESCC.

A novel tumor spheroid model identifies selective enhancement of radiation by an inhibitor of oxidative phosphorylation

There is a need for preclinical models that can enable identification of novel radiosensitizing drugs in clinically relevant high-throughput experiments. We used a new high-throughput compatible total cell kill spheroid assay to study the interaction between drugs and radiation in order to identify compounds with radiosensitizing activity. Experimental drugs were compared to known radiosensitizers and cytotoxic drugs clinically used in combination with radiotherapy. VLX600, a novel iron-chelating inhibitor of oxidative phosphorylation, potentiated the effect of radiation in tumor spheroids in a synergistic manner. This effect was specific to spheroids and not observed in monolayer cell cultures. In conclusion, the total cell kill spheroid assay is a feasible high-throughput method in the search for novel radiosensitizers. VLX600 shows encouraging characteristics for development as a novel radiosensitizer.

HER2/neu (ERBB2) expression and gene amplification correlates with better survival in esophageal adenocarcinoma

BACKGROUND

HER2 (ERBB2 or HER2/neu) is a tyrosine-kinase increasing cell proliferation. Overexpression/amplification of HER2 is correlated with worse prognosis in solid malignancies. Consequently, HER2 targeting is established in breast and upper gastrointestinal tract cancer. There are conflicting data concerning the impact of HER2 overexpression on esophageal adenocarcinoma (EAC), as most studies do not differ between cancers of the esophagus/gastroesophageal junction and the stomach. The aim of this study was to analyze the expression/amplification of HER2 in EAC in correlation to clinicopathological data to verify its prognostic impact.

METHODS

We analyzed 428 EAC patients that underwent transthoracic thoraco-abdominal esophagectomy between 1997 and 2014. We performed HER2 immunohistochemistry (IHC) according to the guidelines and fluorescence-in-situ-hybridization (FISH) for IHC score2+, using tissue micro arrays (TMA) with up to eight biopsies from the surface and infiltration area of a single tumor for evaluating HER2-heterogeneity and single-spot TMA. The HER2-status was correlated with clinicopathological data.

RESULTS

HER2-positivity was found in up to 14.9% in our cohort (IHC score 3+ or IHC score 2+ with gene amplification) and demonstrated a significantly better overall survival (OS) in correlation to HER2-negative tumors (median OS 70.1 vs. 24.6 months, p = 0.006). HER2-overexpression was more frequently seen in lower tumor stages (pT1/pT2, p = 0.038), in the absence of lymphatic metastases (pN0/pN+, p = 0.020), and was significantly associated with better histological grading (G1/G2) (p = 0.041).

CONCLUSION

We demonstrated a positive prognostic impact of HER2 overexpression in a large cohort of EAC, contrary to other solid malignancies including gastric cancer and breast cancer, but consistent to the results of a large study on EAC from 2012.

IL-4, a direct target of miR-340/429, is involved in radiation-induced aggressive tumor behavior in human carcinoma cells

Radiotherapy induces the production of cytokines, thereby increasing aggressive tumor behavior. This radiation effect results in the failure of radiotherapy and increases the mortality rate in patients. We found that interleukin-4 (IL-4) and IL-4Rα (IL-4 receptor) are highly expressed in various human cancer cells subsequent to radiation treatment. In addition, IL-4 is highly overexpressed in metastatic carcinoma tissues compared with infiltrating carcinoma tissues. High expression of IL-4 in patients with cancer is strongly correlated with poor survival. The results of this study suggest that radiation-induced IL-4 contributes to tumor progression and metastasis. Radiation-induced IL-4 was associated with tumorigenicity and metastasis. IL-4 expression was downregulated by miR-340 and miR-429, which were decreased by ionizing radiation (IR). Radiation-regulated miR-340/429-IL4 signaling increased tumorigenesis and metastasis by inducing the production of Sox2, Vimentin, VEGF, Ang2, and MMP-2/9 via activating JAK, JNK, β-catenin, and Stat6 in vitro and in vivo. Our study presents a conceptual advance in our understanding of the modification of tumor microenvironment by radiation and suggests that combining radiotherapy with genetic therapy to inhibit IL-4 may be a promising strategy for preventing post-radiation recurrence and metastasis in patients.

Phloretin induces apoptosis of human esophageal cancer via a mitochondria-dependent pathway

2,4,6-trihydroxy-3-(4-hydroxyphenyl)-propiophenone (phloretin) is found in apple tree leaves and the Manchurian apricot, and is a potent compound that exhibits anti-inflammatory, antioxidant and antitumor activities. However, the effect of phloretin on esophageal cancer cells is not well-defined. The present study aimed to examine whether and how phloretin induced apoptosis in human esophageal cancer cells. EC-109 cells were cultured in Dulbecco's modified Eagle's medium and incubated with 60, 70, 80, 90 and 100 µg/ml phloretin for 6, 12, 24 and 48 h. Cell proliferation was measured by an MTT assay. Cell apoptosis rate was measured using flow cytometric analysis subsequent to propidium iodide (PI) staining. The protein expression levels were determined by western blot analysis. It was found that phloretin significantly decreased viable cell numbers in a dose- and time-dependent manner and induced apoptosis in EC-109 cells. Additionally, phloretin exhibited potent anticancer activity in vitro, as evidenced by the downregulation of the anti-apoptosis-associated molecule B-cell lymphoma 2 (bcl-2) and an increase in the levels of the apoptosis-associated molecules bcl-2-like protein 4 and tumor protein p53. Phloretin treatment also affected the expression of apoptotic protease activating factor-1, the protein product of the direct binding of the inhibitor of apoptosis protein with low PI to the X-linked inhibitor of apoptosis protein. The present results indicated that phloretin may inhibit EC-109 cell growth by inducing apoptosis, which may be mediated through a mitochondria-dependent pathway.

Long noncoding RNA MALAT1 affects the efficacy of radiotherapy for esophageal squamous cell carcinoma by regulating Cks1 expression

OBJECTIVE

Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been well studied in the progression of many malignancies. However, its association with the radioresistance of tumors has not been well understood yet. This study tried to explore the role of MALAT1 in regulating the radiosensitivity of esophageal cancer (EC), especially esophageal squamous cell carcinoma (ESCC), involving its regulation on Cks1 expression.

METHODS

KYSE150 cells were subcutaneously inoculated into nude mice to establish ESCC xenografts. Real-time PCR and Western blot analysis were performed to detect the expression of MALAT1 and Cks1 in irradiated xenografts and cells. Functional analysis was performed in both EC9706 and KYSE150 cells via the transfection of corresponding plasmids or small interfering RNAs (siRNAs). Irradiation-induced damage was examined by the detection of cell viability and apoptosis using MTT and TUNEL assays, respectively.

RESULTS

Both MALAT1 and Cks1 were downregulated in irradiated xenografts and cells. Cks1FER1L4 showed significant downregulation. Overexpression of MALAT1 inhibited irradiation-induced decrease in cell viability, increase in apoptosis, and downregulation of Cks1. Cks1 expression was also downregulated by MALAT1 siRNA, while Cks1 siRNA strongly recovered MALAT1-induced radioresistance in vitro. Moreover, better tumor growth, accompanied by Cks1 upregulation, was observed in KYSE150 xenografts with MALAT1 overexpression, especially under radiation treatment.

CONCLUSION

MALAT1 acted as one positive regulator of the radioresistance of ESCC, at least partly due to its promotion on Cks1 expression. Furthermore, MALAT1-targeted therapies showed great potential in enhancing the radiotherapeutic effect on ESCC.

eEF2K promotes progression and radioresistance of esophageal squamous cell carcinoma

OBJECTIVES

To investigate the biological function of eEF2K in esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

Tissue microarrays containing 100 pairs of ESCC tumor and adjacent normal tissues were completed. Overexpression and knockdown of eEF2K were constructed in ECA-109 and TE-13 ESCC cells. DNA damage, cell viability, migration and invasion, radioresistance, apoptosis and autophagy were determined by immunofluorescence, CCK-8, transwell assay, colony formation assay, flow cytometry and western blot, respectively. Tumor growth and radioresistance were also evaluated using xenograft models created in nude mice.

RESULTS

eEF2K expression was higher in ESCC tissues compared with matched non-tumor tissues (P<0.05). Proliferation was increased in eEF2K overexpressing cells compared with controls (P<0.05), while silencing eEF2K reduced cell proliferation (P<0.05). Furthermore, lower levels of eEF2K expression correlated with slower migration and invasion rates (P<0.05), while higher levels of eEF2K expression with faster migration and invasion rates (P<0.05). eEF2K overexpression resulted in radioresistance and radiation-induced autophagy, and reduced radiation-induced apoptosis compared with controls, but silencing eEF2K promoted radiosensitivity and apoptosis, and reduced autophagy. In addition, eEF2K overexpression promoted the tumor growth in vivo (P<0.01). Combined treatment of NH125 (a pharmacological inhibitor of eEF2K) and radiation was more effective at delaying xenograft tumor growth than NH125 and radiation alone (P<0.05).

CONCLUSION

eEF2K induced progression and radioresistance in ESCC, which may be a novel therapeutic target for ESCC to increase radiosensitivity.

Can involved-field irradiation replace elective nodal irradiation in chemoradiotherapy for esophageal cancer? A systematic review and meta-analysis

Chemoradiotherapy is the most common treatment for inoperable esophageal cancer. However, there is no consensus on the delineation of the clinical target volume. Elective nodal irradiation (ENI) is recommended for inoperable esophageal cancer. A few studies have reported a decrease in the incidence of radiation-related toxicity of involved-field irradiation (IFI) for esophageal cancer. A systematic review and pooled analysis were performed to determine whether IFI in definitive chemoradiotherapy was more beneficial than ENI for esophageal cancer. The results showed no significant differences in the overall survival and local control rates between the IFI and ENI arms. Meanwhile, the incidences of esophageal and lung toxicities were significantly decreased in the IFI arm. These results suggest that IFI is a feasible treatment option for locally advanced esophageal cancer, especially to minimize irradiation-related toxicity.

Barriers to Accessing Optimal Esophageal Cancer Care for Socioeconomically Disadvantaged Patients

BACKGROUND

The 5-year survival of patients with low socioeconomic status (SES) and esophageal cancer is significantly lower than that in patients with high SES. It is poorly understood what causes these worse outcomes. We hypothesized that a qualitative approach could elucidate the underlying causes of these differences.

METHODS

Patients with a diagnosis of esophageal cancer were recruited through flyers in regional cancer centers as well as through Facebook advertisements in cancer support groups and newspapers; they participated in a 1-hour semistructured interview or completed an online survey. Patients were stratified into low- and high-SES groups and were surveyed about their health history and access to cancer care. Data were coded into common themes based on participant responses.

RESULTS

Eighty patients completed the interviews or surveys, with 38 in the high-SES group and 42 in the low-SES group. There were no clinically significant differences between the groups in comorbidities and cancer staging. Patients with low SES were offered operative treatment at significantly lower rates (19 of 42 [44.7%] versus 29 of 38 [76.3%]; p = 0.0048), had a decreased rate of second opinions (10 of 42 [23.8%] versus 25 of 38 [65.8%]; p = 0.00016), and were more likely to lose their jobs (14 of 42 [33.3%] versus 1 of 38 [2.6%]; p = 0.00044) than their high-SES counterparts. Thematic analysis found that communication difficulties, lack of understanding of treatment, and financial troubles were consistently reported more prominently in the lower-SES groups. Having a facilitator (eg, social worker) improved care by helping patients navigate complex treatments and financial concerns.

CONCLUSIONS

Financial and communication barriers exist, which may lead to disparities in cancer outcomes for patients with low SES. There is a critical need for medical advocates to assist patients with limited resources.

Factors Influencing Compliance to Radical Treatment of Middle Thoracic Esophageal Cancer: An Audit from a Regional Cancer Centre

BACKGROUND

The aim of this study is to identify the factors responsible for interruption of planned treatment in patients of carcinoma mid-thoracic esophagus and also discuss the strategies for improving treatment completion rates.

MATERIALS AND METHODS

Patients with nonmetastatic mid-thoracic esophageal cancer who received treatment by multimodality approach using chemotherapy, radiation, and/or surgery were retrospectively analyzed. Factors influencing compliance with planned treatment completion were evaluated, and their significance was determined using multivariate Cox regression analysis.

RESULTS

Ninety-one patients were reviewed. Median follow-up period was 11 months. Of 15 patients planned with neoadjuvant chemoradiation followed by surgery (Group 1), only 6 (40%) could complete the treatment. Similarly, only 19 out of 36 patients (52.8%) completed the planned definitive chemoradiation (Group 2). Furthermore, of forty patients planned with definitive radiotherapy (Group 3), 29 patients only (72.5%) completed this schedule. The rate of completion of therapy was worst in Group 1. The most common reason for noncompletion of planned treatment was nutritional inadequacy and excessive weight loss in all groups. In addition, chemotherapy-induced myelosuppression (P = 0.05) was the factor leading to treatment interruption in Group 2 and radiation-induced acute mucositis (P = 0.02) and lost to follow-up (P = 0.02) were the factors in Group 3.

CONCLUSIONS

Rate of treatment completion significantly impacts survival rates. Nutritional inadequacy was the most common factor for noncompletion of planned treatment. A well-trained management team consisting of oncologist, dietitian, and psychotherapist can help overcome these factors and thereby improve the treatment completion rates.

miR-29b attenuates tumorigenicity and stemness maintenance in human glioblastoma multiforme by directly targeting BCL2L2

Glioblastoma multiforme (GBM) is the most common malignant brain tumor and exhibits aggressive and invasive behavior. We previously identified four miRNAs—miR-29b, 494, 193a-3p, and 30e—with enhanced expression in GBM following treatment of ionizing radiation by miRNA microarray analysis. In this study, we found that only miR-29b inhibited tumor cell migration and invasion by reducing MMP-2 activity via phospho-AKT/β-catenin signaling, and stimulated a more epithelial-like morphology. Moreover, miR-29b inhibits angiogenesis by attenuating tube formation and the expression of VEGF and Ang-2, and stemness maintenance in GBM cells, as demonstrated by decreasing neurosphere formation and cancer stem cell marker protein expression. These findings support the anti-tumor properties of miR-29b in human GBM cells. Furthermore, miR-29b expression was inversely proportional to that of BCL2L2 mRNA or protein in various cancer cell types. Interestingly, BCL2L2 mRNA is highly expressed in the mesenchymal type of GBM. To further elucidate the relationship between miR-29b and BCL2L2 in GBM, we performed co-transfection reporter assays and determined that miR-29b downregulates BCL2L2 expression by directly binding its 3′UTR. Finally, we confirmed that BCL2L2 repression is of central importance to miR-29b anti-tumor activity using functional assays to examine cell migration, invasion, angiogenesis, and stemness. From these data, we propose that miR-29b may be a useful therapeutic agent in GBM.