bluuebunny/crossref_metadata_2025_split huggingface dataset:
ACTL6A to drive gastric cancer progression through induction of glutathione synthesis.
Authors: Fang Lekun , Yang Ziqing , Zou Shaomin , Xie Yunling 
Published: May 2020

e16521 Background: Actin-like 6A (ACTL6A), an actin-like protein, is a member of ATP-dependent SWI/SNF like BAF chromatin remodeling complexes. Previous reports revealed that ACTL6A was involved in varying cellular processes including chromatin remodeling, transcriptional regulation, vesicular transport, and nuclear migration. Nevertheless, its role and mechanism in Gastric Cancer (GC), the second leading causes of cancer-related death worldwide, has not been reported. To explore it, we found that ACTL6A inhibits ferroptosis of GC cells via regulating glutathione (GSH) metabolism. Ferroptosis is a regulated form of cell death driven by accumulation of lipid-based reactive oxygen species (ROS). Methods: GC cell line snu638 was used for studies. Firstly, silencing ACTL6A in snu638 with shRNA, cell proliferation was measured by counting cell confluence in incucyte. Overlapping the Gene Set Enrichment Analysis (GSEA) results of RNA-sequencing and two databases, we found that ACTL6A is positively correlated with GSH metabolism, which can be validated by real time-PCR. Next, cells were treated with ferrostatin-1 (fer-1), a ferroptosis inhibitor, to check if ACTL6A can inhibit ferroptosis. Finally, 13C-glucose and 13C-glutamine were used for tracing the metabolites in snu638, which were measured by LC-MS system. Results: Suppression of ACTL6A significantly inhibits GC cell growth. In our RNA-sequence results, ACTL6A is positively correlated with GSH metabolism, which is also enrich in two GC databases. ROS level was increased after ACTL6A knockdown. Since ROS plays an important role in ferroptosis, we found that fer-1 can rescue cell death caused by suppression of ACTL6A. When tracing with 13C-glucose, total GSH and 13C incorporation from 13C-glucose in the m+2 and m+4 isotopomer of GSH is reduced when ACTL6A is depleted, while total contribution of U-13C glucose to serine, glycine and glutamate have no significant changes. When tracing with 13C-glutamine, m+5 fractional contributions of 13C-glutamine to γ-glutamyl-cysteine and GSH are decreased when silencing ACTL6A. These results reveal that ACTL6A promotes de novo GSH synthesis. Conclusions: ACTL6A acts as an oncogene in GC via regulating GSH metabolism, and ferroptosis is inhibited for increasing GSH by ACTL6A, which highlights the importance of ACTL6A in GC metabolism and tumorigenesis. Therefore, ACTL6A could be a potential diagnosis marker or target gene of chemotherapy for GC.
High intra-tumor heterogeneity observed in esophageal squamous cell carcinoma.
Authors: Xue Jun , Li Yingqiang , Mu Tianhao , Chen Shifu 
Published: May 2020

e16522 Background: Intra-tumor heterogeneity (ITH) is a critical factor in the metastasis of esophageal squamous cell carcinoma (ESCC). Analysis of ITH facilitates better diagnosis and medication. Cosine distance similarity reflects the directional relationship of each vector to analyze ITH better. Methods: Whole Exome Sequencing (WES) data of 185 tumor regions and 39 normal esophageal tissues from 39 patients were collected from NCBI database. We found highly variable SNPs in the East Asian populations from ExAC, GenomAD and other databases, and calculated the cosine distance of the SNPs between each tumor sample with the corresponding paracancerous sample. Sliding windows were incrementally advanced along the genome. Results: All 39 samples exhibited spatial ITH. Significant long distances were observed in patients with metastatic lymph nodes, and the homologous samples of the patients were roughly identical. In contrast, the sliding windows of different samples presented a distinctly heterogeneous scene. Conclusions: The cosine distance is suitable for the similarity calculation of high-dimensional vectors. The similarity of different samples can be calculated by using mutation sites as vectors. The cosine distance can be used to present further information and graph composition, compared with digital information. In the future, different samples can be clustered based on cosine distance by recruiting more samples and machine learning.
Resting memory CD4+ T cells and plasma cells in gastric cancer may be potential immune biomarkers.
Authors: Chen Jingde , Zhang Bei , Zhou Yifan , Zhao Xiaochen , Bai Yuezong 
Published: May 2020

e16523 Background: Previous studies revealed the CD8+T cells deeply involved in tumor progress and reaction to immunotherapy. Now we used expression data and in silicon algorithm to analyze immune cell composition in gastric cancer and explored other subsets of immune cells that may be the potential immune biomarkers. Methods: CIBERSORT quantified 22 immune cell subtypes using four GEO gastric cancer cohorts (GSE15459, GSE26253, GSE29272, GSE57303) and TCGA-STAD, TCGA-PAAD gene expression data, and only CIBERSORT P- value of < 0.05 were included in the survival analysis. Immune cell high was defined as ≥median cells proportion individually and were computed for survival analysis and hazard ratios. Wilcox test was applied to analyze the differences between normal and tumor tissues. Log-rank Mantel-Cox test was applied to compare the survival curves between the patient groups. Statistical analyses were conducted using R v3.3.2. Results: Unsupervised hierarchical analysis of four GEO gastric tumor cohort using 22 immune cells proportions identifies three subclasses. In the subclass with the best overall survival performance, we found enriched resting CD4 T memory cells. Then in TCGA-STAD (P = 0.03) and TCGA-PAAD (P = 0.03) cohort, we observed that normal tissue obtained higher fraction of resting CD4 T memory cells than tumor. On the other hand, in patients who administrated chemotherapy in TCGA-STAD, by comparing immune cell high and low subgroup, we found that plasma cells (P = 0.02), T cells CD8(P = 0.03) were associated with improved overall survival. while, neutrophils(P = 0.05), NK cells resting(P = 0.04), were correlated with decreased overall survival. Also we proved one similar result in GEO cohort, that plasma cells-high (above median) subgroup provided increased overall survival (P = 0.04, HR = 0.76). In contrast, other three immune cells were not significantly associated with survival benefits. Conclusions: Together, these results indicated that memory CD4 T cells and plasma cells infiltration in gastric cancer have important clinical meanings and may be potential immune biomarkers. The continued integration of observations from a variety of experimental models will be required to further understand and utilize the full potential of immune cells.
The IL-6/STAT3 signaling pathway mediated by radiotherapy regulates the expression of PD-L1 and affects the biological functions of esophageal cancer cells.
Authors: Zhou Yichen , Zhu Honglei , Pang Xuezhou , Shen Yang , He Yu , Ma Daiyuan ,   ASCO Authors' Group
Published: May 2020

e16531 Background: The mechanism by which radiotherapy regulates PD-L1 expression and affects the biological behavior of esophageal cancer cells is not clear.The IL-6 /STAT3 signaling pathway may be involved. Methods: After irradiation of different doses to the esophageal cancer cell lines (Eca109, KYSE150, and TE1), RT-PCR and Western blotting were used to detect PD-L1, STAT3 and P-STAT3, ELISA was performed to examine the effects on IL-6, CCK-8 assays were used to test the effects on the proliferation. After the optimal dose radiation, Transwell assays were used to detect the invasion and proliferation of cell clones, and cell cycle changes were detected by flow cytometry. Results: The mRNA and the protein expression of PD-L1 in the cancer cell lines was significantly higher than in the normal esophageal cell line HET-1A(P < 0.01). The PD-L1 mRNA levels first increased and then decreased, which peaked 12 hours after 3,6,9,12Gy irradiation and was significantly higher than in nonirradiated cells (P < 0.05). PD-L1 protein expression first increased and then decreased, which peaked 48 hours after 6 Gy irradiation (P < 0.05). P-STAT3 protein expression first increased and then decreased after 6Gy irradiation (P < 0.05), that the expression in Eca109 peaked 48 hours but in KYSE150 and TE1 peaked 24 hours (P < 0.05). IL-6 protein expression peaked 12 hours and decreased gradually after irradiation (P < 0.05). The proliferation levels of the the cancer cell lines decreased after irradiation, and the inhibitory force increased with the increase in dose and time after radiotherapy (P < 0.05). The clone formation ability of the cancer cell lines was inhibited to varying degrees 14 days after irradiation with 6 Gy(P < 0.05). After 48 hours irradiation with 6 Gy, and the invasion ability of the cancer cell lines was lower than that of the nonirradiated cell lines (P < 0.05), and the proportion of cells in G2/M phase was higher in exposed cells than in nonexposed cells (P < 0.05), while the proportion of cells in S phase did not change significantly. Conclusions: PD-L1, IL-6 and STAT3 protein expression in the esophageal cancer cell lines first increased and then decreased consistency after irradiation, radiotherapy could regulate PD-L1 expression through the IL-6/STAT3 signaling pathway and affect the biological functions of esophageal cancer.
Glutathione system in the blood of gastric cancer patients with various tumor histotypes and prevalence of the disease.
Authors: Goroshinskaya Irina A. , Surikova Ekaterina I. , Frantsiyants Elena M. , Nemashkalova Ludmila A. , Kachesova Polina S. , Chudilova Anastasiya V. , Medvedeva Dar'ja E. , Maslov Andrey A. , Malinin Sergey A. , Kit Oleg I. , Fomenko Yuriy A. , Petrov Dmitry S. 
Published: May 2020

e16534 Background: The role of oxidative stress in tumor growth and the multifaceted functional significance of glutathione have led to an interest in studying the components of the glutathione-dependent system in gastric cancer (GC), which occupies a leading position in cancer incidence and mortality. The aim of this work was to study the functioning of the glutathione system in the red blood cells of patients with gastric cancer in a comparative aspect depending on the histotype of the tumor and the prevalence of the disease. Methods: The study included 89 patients with GC divided into 6 groups depending on the histotype of the tumor. Separately, the results of the study were analyzed in patients with T4 status according to TNM and in patients with stage IV cancer. The content of reduced glutathione and the activity of glutathione-dependent enzymes were studied by conventional spectrophotometric methods in the red blood cells of patients. Statistical processing of the results was performed using the Statistika 6.0 program with Student’s t-test for two independent groups. Results: An increase in the content of glutathione in patients with GC compared with the group without oncopathology was revealed. The maximum increase was observed in patients with low-grade adenocarcinoma - by 42.5%, while in signet ring cell cancer (SRCC) there was only a tendency to increase by 17.8%. Glutathione reductase activity was reduced in adenocarcinoma by 23.4-26.2% and did not change in SRCC. The activity of the antioxidant enzymes glutathione peroxidase and glutathione transferase was increased in all groups and especially in SRCC - by 76% and 23-29%, respectively. In patients with T4 status and at stage 4 of the process, lower activity of the studied glutathione-dependent enzymes was revealed compared with all other groups of patients. Conclusions: The data indicate a greater functional potential of the glutathione system in SRCC. A significant increase in the activity of glutathione transferase with a sufficiently high level of reduced glutathione contributes to the development of treatment resistance in patients with SRCC.
Irinotecan with or without capecitabine as a beyond 2nd line regime for esophago-gastric adenocarcinomas.
Authors: Hapuarachi Sonal Brindley , Dawod Mohammed , Weaver Jamie , Shaheen Fadhel , Khan Adeel , Hubner Richard , Waddell Tom , Mansoor Wasat 
Published: May 2020

e16545 Background: Purpose: The aim of this retrospective study was to assess the efficacy and toxicity of irinotecan +/- capecitabine for patients with metastatic esophago-gastric (EG) adenocarcinomas previously treated with at least two chemotherapy regimens including platinum-based, fluoropyramidines and taxanes. Introduction: Treatment for metastatic EG cancer beyond 2nd line remains controversial. Recently, the TAGS phase III trial (Shitara et al., 2018) showed overall survival benefit with Trifluridine/tipiracil of 2.1 months compared to placebo as a third line. Apatinib is also approved for use as third line in China (Li et al., 2013). Based on minimal evidence (Kang et al., 2013), irinotecan in combination with capecitabine is used in the UK. We performed a retrospective study to assess the efficacy and toxicity of irinotecan as a beyond 2nd line regime in metastatic EG adenocarcinomas in one of Europe’s largest cancer centres, The Christie. Methods: Data was collected retrospectively from all metastatic EG adenocarcinoma patients who were treated with irinotecan +/- capecitabine as a beyond 2nd line palliative treatment at the Christie Hospital from January 2014 to December 2019. Irinotecan was either given 2 or 3 weekly at dose of 180 mg/m² with or without capecitabine 800 mg/m². Response rate (RR) was calculated according to RECIST version 1.1, overall survival measured and toxicity data collected. Results: Fifty-six patients received irinotecan as beyond 2nd line palliative chemotherapy. Out of the thirty-seven patients with measurable disease on their scans, the overall response rate was 8.1% and the disease control rate was 51.4% as per RECIST 1.1. Median overall survival was 5 months (95% CI 4.2-5.8). The presence of grade 3-4 toxicities was 16% (9 patients) and included neutropenia, fatigue, nausea and diarrhea. On average, 3.7 cycles were administered, 32% (18 patients) required dose reductions, mainly secondary to grade 2 diarrhea and fatigue. Conclusions: Irinotecan in combination with capecitabine is efficacious as a beyond 2nd line regime in metastatic EG with an acceptable toxicity profile with a limited role in patients with resistant disease to first line platinum-based chemotherapies with fluoropyramidines.
Tepotinib inhibits the epithelial-mesenchymal transition and tumor growth of gastric cancers via increasing GSK3β, ECAD, MUC5AC, and MUC6.
Authors: Zang Dae Young , Sohn Sung-Hwa , Kim Bohyun , Sul Hee Jung , Jeong Jinhui , Kim Bum Jun , Kim Hyeong Su 
Published: May 2020

e16562 Background: Aberrant expression of mucins can promote the epithelial-mesenchymal transition (EMT), which leads to enhanced tumorigenesis. Carcinogenesis-related pathways involving c-MET and beta-catenin involve mucins. This study characterized expressions of MET, MUC5AC, MUC5B, and MUC6 EMT signaling in human gastric cancer (GC) cell lines, and further characterized the differential susceptibility of these cell lines to tepotinib. Methods: We assessed the antitumor activity of tepotinib in GC cell lines. The effect of tepotinib on cell viability (IC50), apoptotic cell death, the EMT, and c-MET and beta-catenin signaling were evaluated by MTS assay, flow cytometry, western blotting, and qRT-PCR. Antitumor efficacy was assessed in MKN45 xenograft mice. Results: Tepotinib treatment showed dose-dependent growth inhibition of c-MET-amplified SNU620, MKN45, and KATO III cells with concomitant induction of apoptosis, but tepotinib treatment did not have an effect on c-MET-reduced MKN28 and AGS cells. Tepotinib treatment also significantly reduced expressions of phospho-c-MET, total c-MET, phospho-ERK, total ERK, beta-catenin, and c-Myc protein in SNU620 and MKN45 cells. In contrast, this drug was only slightly active against KATO III cells. Notably, tepotinib significantly reduced the expressions of EMT promotion genes such as MMP7, COX-2, WNT1, MUC5B, and c-Myc in c-MET-expressed GC cells, and increased expressions of EMT suppression genes such as MUC5AC, MUC6, GSK3beta, and ECAD. In a murine xenograft model, tumor volumes were significantly reduced in the tepotinib-treated group, when administered by daily oral gavage at a dose of 10mg/kg/day. Histologically, tepotinib induced more necrosis than in the control group. Conclusions: These data show the possibility that tepotinib may have therapeutic effects in c-MET-amplified GC, suggesting that clinical studies need to confirm the therapeutic effect.
The impact of neoadjuvant and/or adjuvant treatment modalities in resectable gastric cancer (rGC).
Authors: Ng Camille , Kim Sungjin , Guan Michelle , Hendifar Andrew Eugene , Kim Haesoo , Liu Jar-Yee , Mehta Sejal , Placencio-Hickok Veronica , Gangi Alexandra , Klempner Samuel J , Burch Miguel , Chao Joseph , Cho May Thet , Kamrava Mitchell , Atkins Katelyn Mae , Gong Jun 
Published: May 2020

e16564 Background: In rGC ( > cT2), we investigated the impact of various neoadjuvant and/or adjuvant treatment modalities on pathologic complete response (pCR), surgical margins, and overall survival (OS). Methods: The National Cancer Database (NCDB) was interrogated to identify rGC patients (pts) between 2004-2015. Gastric adenocarcinoma cases that were cT2-T4b, any N, M0 and underwent definitive surgery were included. We analyzed the association of 9 treatment groups: neoadjuvant chemoradiation only (nCRT), neoadjuvant chemo only (nCT), adjuvant chemo only (aCT), adjuvant chemoradiation only (aCRT), neoadjuvant chemo and adjuvant radiation (nCTaRT), received any chemo at all (any CT), received any chemoradiation at all (any CRT), received any radiation at all (any RT), and no perioperative therapy (NT) across 3 endpoints: pCR, margin status, and OS using logistic regression and Cox proportional hazards models with adjustment for baseline characteristics. Results: From 183,204 GC cases screened, a total 3061 pts were available with a median follow-up of 41.6 mos and median OS of 29.0 mos. On multivariable analyses, nCRT was associated with the greatest odds of having a pCR (odds ratio or OR 59.6, 95% confidence interval (CI) 10.6-334.1, p < 0.001) with NT as the reference. Having received any RT (OR 0.42, 0.10-1.86), nCRT (OR 0.68, 0.33-1.37), or nCT (OR 0.83, 0.60-1.15) was associated with the lowest odds for having positive surgical margins although none reached p < 0.05. For OS, having received any CT (hazard ratio or HR 0.41, 0.35-0.48) was associated with the lowest risk of death followed by nCRT (HR 0.48, 0.35-0.66), aCT (HR 0.52, 0.43-0.62), aCRT (HR 0.55, 0.48-0.63), any CRT (HR 0.61, 0.41-0.91), nCT (HR 0.62, 0.54-0.71), and nCTaRT (HR 0.67, 0.52-0.87, all p < 0.05). Median OS was greatest in pts treated with any CT (53.9 mos) followed by nCRT (39.1 mos) and aCT (36.1 mos) with 2-year OS rates being 65.6% (95% CI 61.3-69.5%), 63.6% (52.3-73.0%), and 59.7% (54.2-64.7%), respectively. Conclusions: Although nCRT had a high pCR rate, receipt of any CT (neoadjuvant and/or adjuvant) afforded the greatest OS in this modality-by-modality comparison in a large cohort of rGC pts.
Tumor response score with neoadjuvant FLOT versus FOLFOX in gastric cancer patients: Results from a United States-based cohort.
Authors: De Andrade James Pereira , Ahn Hye Seong , Chao Joseph , Melstrom Laleh Golkar , Paz Isaac Benjamin , Fong Yuman , Lee Byrne , Woo Yanghee 
Published: May 2020

e16573 Background: A recent RCT comparing FLOT and ECF regimens for locally advanced gastric cancer found FLOT to be superior in pathologic complete response (PCR) rates: 16% versus 6%. We evaluated patients who underwent resection after FLOT and FOLFOX in a diverse US population. Methods: Patients diagnosed with gastric adenocarcinoma at a single institution who underwent preoperative chemotherapy either with FLOT or FOLFOX between 2017 and 2019 were evaluated for pathologic response. Results: Fifty-nine patients underwent gastrectomy for adenocarcinoma. Of these, 59% underwent neoadjuvant chemotherapy: FLOT 20 patients, FOLFOX 12 patients, ECF 1 patient, other regimen 2 patients. Racial/ethnic background of patients were 20% non-Hispanic white, 23% Hispanic/Latino, 40% Asian, 6% black, and 6% other. Three patients (8.6%) had PCR, two received FLOT and one FOLFOX. Four patients had a near complete response (tumor regression score 1), all of whom received FLOT. In total, 16 of 20 patients who received FLOT had at least a partial response whereas only 5 of 12 patients who received FOLFOX had any tumor response (p = 0.027). Among all patients receiving neoadjuvant chemotherapy, 66% had poorly differentiated tumors. Only 1 of these patients experiencing a complete or near complete response compared to 50% of patients with non-poorly differentiated tumors (p = 0.001). Conclusions: In an ethnically diverse US population, tumor regression rates were improved with FLOT when compared to FOLFOX. For medically appropriate patients, strong consideration should be given for FLOT in the neoadjuvant setting.
Immunogenomic classification of gastric cancer based on the tumor microenvironments expression of PD-L1 and CD8+ T-cell infiltration.
Authors: Chen Yu , Chen Gang , Xiong Jia-ni , Lan Bin , Gao Xuan , Jun Liu , Lin Jin , Xu Yaping , Guan Yan-Fang , Chen Ling , Chen Li-zhu , Xia Xuefeng , Guo Zengqing 
Published: May 2020

e16578 Background: Previous data has shown that a positive response to immunotherapy usually relies on active interactions between tumor cells and immunomodulators inside the tumor microenvironment (TME). The aim of this study was to classify gastric cancer (GC) subsets based on the TME immune status according to the expression of PD-L1 and infiltration of CD8+ T cells. Methods: One hundred and eighty-six tumor tissue from gastric cancer patients with a curative D2 gastrectomy were examined for evaluating PD-L1 and CD8+ T cells status using histopathologic analysis. The molecular characteristics of 289 GC samples in TCGA network were further analyzed to distinguish the genetic features of four immune subtypes depending on the presence of PD-L1/CD8+T cell. Results: GC samples were categorized into four types, type I (CD8+/PD-L1+, 60.3%), II (CD8-/PD-L1-, 11.8%), III (CD8-/PD-L1+, 0%), and IV (CD8+/PD-L1-, 27.9%), basing on PD-L1/CD8 expression. The PD-L1 expressing level was geographically associated with the intensity of CD8+ T cell infiltration which was significantly associated with disease-free survival (DFS) and overall survival (OS) (p = 0.003 and p = 0.006). Distinct patterns of genetic profile were described in four types of GC from TCGA database. Type I and III which PD-L1 were overly expressed had comparatively higher MSI and TMB, with EBV mainly enriched in Type I, whereas CIN was more likely to occur in PD-L1 aberrant types II and IV. SNV analysis illustrated higher gene mutations in oncogenes (PIK3CA and ERBB2), and in DNA damage repair related pathway, such as PRKDC, ATM, and SWI/SNF complexes (e.g. ARID1A) in Type I. However, TP53 mutations tend to enrich in Type II and IV. Similar results were obtained by transcriptome analysis. Conclusions: The genetic features of four immune subtypes proof that PD-L1 and CD8+ T cells status are reasonable immunogenomic classification of gastric cancer. SNV analysis prompts a potential mechanism for effectiveness of immunotherapy in Type I patients. Overall, the results may be useful for the development of clinical treatments for the blockade of immune checkpoints.