Dawn of precision medicine on gastric cancer

Clinical application of targeted tumour sequencing tests for detecting ERBB2 amplification and optimizing anti-HER2 therapy in gastric cancer

BACKGROUND

Evaluation of human epidermal growth factor receptor 2 (HER2) overexpression caused by erb-b2 receptor tyrosine kinase 2 (ERBB2) amplification (AMP) by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) is essential for treating unresectable metastatic gastric cancer (GC). A targeted tumour sequencing test enables comprehensive assessment of alterations in cancer-related genes, including ERBB2. This study aimed to evaluate the concordance between the targeted tumour sequencing test and IHC/FISH for detecting HER2-positive GC and to clarify the significance of ERBB2 AMP and concomitant genetic alterations in HER2 downstream pathways (DPs) in anti-HER2 therapy for unresectable metastatic GC patients.

METHODS

ERBB2 copy number alteration (CNA) was examined via a targeted tumour sequencing test in 152 formalin-fixed paraffin-embedded (FFPE) GC tissues. ERBB2 CNA was compared to HER2 status evaluated by IHC/FISH in FFPE block sections, which were identical to those subjected to the targeted tumour sequencing test. Treatment outcomes of anti-HER2 therapy in 11 patients with unresectable metastatic GC was evaluated.

RESULTS

ERBB2 AMP (≥ 2.5-fold change) was detected by the targeted tumour sequencing test in 15 patients (9.9%), and HER2 positivity (IHC 3 + or IHC 2+/FISH positive) was detected in 21 patients (13.8%). The overall percent agreement, positive percent agreement, negative percent agreement and Cohen's kappa between ERBB2 CNA and HER2 status were 94.7%, 66.7%, 99.2% and 0.75, respectively. Progression-free survival for trastuzumab therapy in patients with ERBB2 AMP was significantly longer than that in patients with no ERBB2 AMP detected by the targeted tumour sequencing test (median 14 months vs. 4 months, P = 0.007). Treatment response to trastuzumab therapy was reduced in patients with ERBB2 AMP and concomitant CNAs of genes in HER2 DPs. One patient with ERBB2 AMP and concomitant CNAs of genes in HER2 DPs achieved a durable response to trastuzumab deruxtecan as fourth-line therapy.

CONCLUSIONS

A targeted tumour sequencing test is a reliable modality for identifying HER2-positive GC. ERBB2 AMP and concomitant genetic alterations detected through the targeted tumour sequencing test are potential indicators of treatment response to trastuzumab therapy. The targeted tumour sequencing test has emerged as a plausible candidate for companion diagnostics to determine indications for anti-HER2 therapy in the era of precision medicine for GC.

Effects of NM23 transfection of human gastric carcinoma cells in mice

Gastric carcinoma is a frequent malignant tumor worldwide. NM23 plays an important role in pathological processes, including in the occurrence and development of tumors. The purpose of this study is to examine the effect of NM23 transfection of human gastric carcinoma cells (BGC-823) on growth and metastases of BGC-823 abdominal cancer xenografts in nude mice. BGC-823 cells were transfected with an adenovirus vector for NM23 (NM23-OE), transfected with an empty vector (NC), or were not transfected (Ctrl). Eighteen female BALB/c-nu mice were randomly divided into three groups (six per group) according to the type of BGC-823 cells administered by intraperitoneal injection. After 2 weeks, necropsies of mice were performed, abdominal circumferences were measured, and abdominal cavities were searched by ultrasound. In order to observe the xenografts in nude mice, there were gross macroscopic observations and microscopic observations. In addition, immunohistochemical analysis and western blot of NM23 were also performed. Green fluorescence in the NM23-OE and NC cells indicated successful transfection. The multiplicity of infection is 80%. A comparison of the three groups of mice indicated the NM23-OE group had positive conditions (abdominal circumferences: 81.83 ± 2.40 mm), but the other groups had negative conditions and enlarged abdomens (NC: 90.83 ± 2.32 mm; Ctrl: 92.67 ± 2.07 mm). Ultrasound observations confirmed large tumors in the NC and Ctrl groups, but did not find in the NM23-OE group. There were no obvious ascites in the NM23-OE group, but the cytological examination of ascites exfoliation in NC and Ctrl groups indicated that there were large and deep-stained gastric carcinoma cells. Tumor expression of NM23 was greater in the NM23-OE group than in the NC and Ctrl groups (both p < 0.05). In conclusion, transfection of BCG-823 cells with NM23 rather than an empty vector (NC) or no vector (Ctrl) led to reduced growth and metastases of abdominal cancer xenografts in nude mice.

Elevation of microRNA-365 impedes malignant behaviors of gastric cancer cells by inhibiting PAX6

MicroRNA-365 (miR-365) has been revealed to be a vital regulator in tumorigenesis of multiple cancers, while there is a large gap in the knowledge about miR-365 expression and gastric cancer (GC). This research focused on the effects of miR-365 and paired box 6 (PAX6) on GC development. Levels of miR-365 and PAX6 in GC tissues and cell lines were determined, followed by the screening of the AGS and NCI-N87 cells. Gain- or loss-of-function assays were used to analyze the effect of miR-365, PAX6 on AGS and NCI-N87 cell behaviors. The effects of altered miR-365 and PAX6 on animal models were observed. Moreover, to assess the interaction between miR-365 and PAX6, we implemented the bioinformatic method and dual luciferase reporter gene assay. MiR-365 was decreased while PAX6 was increased in GC tissues and cell lines. There existed a negative association between miR-365 and PAX6. The promoted miR-365 could repress oncogenicity in vivo and malignant transformation in vitro of GC. PAX6 was the target gene of miR-365. Overexpression of PAX6 reversed the inhibitory effect of up-regulated miR-365 on malignant behavior of gastric cancer cells. Our research displays that the amplification of miR-365 could suppress the malignant behaviors of GC cells via inhibiting PAX6, which may be helpful for GC treatment.

Synthesis of 8-Fluoroneocryptolepine and Evaluation for Cytotoxic Activity against AGS Cancer Cells

Neocryptolepine derivatives have attracted great interest because of their unique cytotoxic activity. 8-Fluoroneocryptolepine (8FNC) was synthesized, and its cytotoxicity was evaluated by MTT assay in AGS gastric cancer cells and gastric mucosa GES-1 cells. 8-Fluoroneocryptolepine showed greater selectivity and cytotoxicity to AGS cells than the cisplatin (CIS) and fluorouracil (5-Fu) commonly used in clinical treatment of gastric cancer. Most importantly, we significantly improved the cytotoxic effect of 8FNC against AGS cells by structural modification and reduced the cytotoxicity against GES-1 cells compared with neocryptolepine. We further evaluated the activity of 8FNC against AGS cells in vitro. Our results indicate that 8FNC arrests the AGS cell cycle in the G2/M phase, reduces the mitochondrial membrane potential of AGS cells, and drives the initiation of apoptotic body formation in 8FNC-induced apoptosis. Moreover, 8FNC exhibits strong inhibitory effects on AGS cell migration. Studies on the molecular mechanisms of the cytotoxic activities of 8FNC revealed that it may play a significant role in the inhibitory effect on AGS human gastric cancer cells through the PI3K/AKT signaling pathway. In conclusion, 8FNC may become a promising lead compound in the development of potential clinical drug candidates for the treatment of gastric cancer.

Long intergenic non-protein coding RNA 467 inhibition elevates microRNA-27b-3p to repress malignant behaviors of gastric cancer cells via reducing STAT3

Emerging evidence indicated that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) exert critical effects on tumorigenesis of multiple malignancies, including gastric cancer (GC). We aim to explore the effects of long intergenic non-protein coding RNA 467 (LINC00467) and miR-27b-3p on GC. GC cells were initially cultured. LINC00467, miR-27b-3p, and signal transducer and activator of transcription 3 (STAT3) expression in GC were detected. The altered LINC00467 and/or miR-27b-3p were transfected into screened cells. Then, the biological activities of GC cells and the tumor growth in vivo were examined. The binding relationships among LINC00467, miR-27b-3p, and STAT3 were confirmed. It was indicated that LINC00467 was increased while miR-27b-3p was decreased in GC tissues and cells. Inhibition of LINC00467 hindered GC cell malignancy and blocked tumor development by upregulating miR-27b-3p. LINC00467 sponged miR-27b-3p and STAT3 was targeted by miR-27b-3p. It was discovered that LINC00467 reduction upregulates miR-27b-3p to repress malignant GC cell growth via inhibiting STAT3. This research may deepen the insight of molecular mechanisms on GC.

Characterization of Total RNA, CD44, FASN, and PTEN mRNAs from Extracellular Vesicles as Biomarkers in Gastric Cancer Patients

Simple Summary

Liquid biopsy is an easily accessible and non-invasive method to gain information about tumor diseases. The purpose of our study was to determine the value of extracellular vesicle-derived mRNAs as biomarkers for the diagnosis of gastric cancer and the response to its treatment. In a cohort of 87 gastric cancer patients and a control group of 14 individuals, we analyzed the absolute RNA concentration from extracellular vesicles (EV) and the relative levels of FASN, PTEN, and CD44 mRNA, and their correlation with clinico-pathological features. These correlated with treatment, tumor grading, and the pathological subtype according to Laurén’s classification. This might reflect their potential as both diagnostic and therapeutic predictors.

Abstract

In-depth characterization has introduced new molecular subtypes of gastric cancer (GC). To identify these, new approaches and techniques are required. Liquid biopsies are trendsetting and provide an easy and feasible method to identify and to monitor GC patients. In a prospective cohort of 87 GC patients, extracellular vesicles (EVs) were isolated from 250 µL of plasma. The total RNA was isolated with TRIZOL. The total RNA amount and the relative mRNA levels of CD44, PTEN, and FASN were measured by qRT-PCR. The isolation of EVs and their contained mRNA was possible in all 87 samples investigated. The relative mRNA levels of PTEN were higher in patients already treated by chemotherapy than in chemo-naïve patients. In patients who had undergone neoadjuvant chemotherapy followed by gastrectomy, a decrease in the total RNA amount was observed after neoadjuvant chemotherapy and gastrectomy, while FASN and CD44 mRNA levels decreased only after gastrectomy. The amount of RNA and the relative mRNA levels of FASN and CD44 in EVs were affected more significantly by chemotherapy and gastrectomy than by chemotherapy alone. Therefore, they are a potential biomarker for monitoring treatment response. Future analyses are needed to identify GC-specific key RNAs in EVs, which could be used for the diagnosis of gastric cancer patients in order to determine their molecular subtype and to accompany the therapeutic response.

Association of CLDN18 Protein Expression with Clinicopathological Features and Prognosis in Advanced Gastric and Gastroesophageal Junction Adenocarcinomas

The tight junction protein claudin-18 (CLDN18), is often expressed in various cancer types including gastric (GC) and gastroesophageal adenocarcinomas (GECs). In the last years, the isoform CLDN18.2 emerged as a potential drug target in metastatic GCs, leading to the development of monoclonal antibodies against this protein. CLDN18.2 is the dominant isoform of CLDN18 in normal gastric and gastric cancer tissues. In this work, we evaluated the immunohistochemical (IHC) profile of CLDN18 and its correlation with clinical and histopathological features including p53, E-cadherin, MSH2, MSH6, MLH1, PMS2, HER2, EBER and PD-L1 combined positive score, in a large real-world and mono-institutional series of advanced GCs (n = 280) and GECs (n = 70). The association of IHC results with survival outcomes was also investigated. High membranous CLDN18 expression (2+ and 3+ intensity ≥75%) was found in 117/350 (33.4%) samples analyzed. CLDN18 expression correlated with age <70 (p = 0.0035), positive EBV status (p = 0.002), high stage (III, IV) at diagnosis (p = 0.003), peritoneal involvement (p < 0.001) and lower incidence of liver metastases (p = 0.013). CLDN18 did not correlate with overall survival. The predictive value of response of CLDN18 to targeted agents is under investigation in several clinical trials and further studies will be needed to select patients who could benefit from these therapies.

Anti-Gastric Cancer Effect of Purified Omphalia lapidescens Protein via Regulating the JAK/STAT3 Signaling Pathway

Gastric cancer is the leading cause of cancer-related death worldwide. The aim of present study was to investigate the anti-tumor effect of purified Omphalia lapidescens protein (pPeOp) in gastric cancer. Microarray analysis was performed to find out differentially expressed genes in pPeOp-treated MC-4 gastric cancer cells. The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) three signaling pathway was most likely to be altered based on bioinformatics analysis. Interleukin-6 (IL-6) and NSC74859 were used as the agonist and inhibitor of the JAK/STAT3 signaling pathway, respectively. Flow cytometry and MTS assay were used for cell proliferation and viability analysis in pPeOp-treated gastric cancer cell lines with IL-6 or NSC74859. The anti-tumor effect was increased when pPeOp were co-treated with IL-6, while decreased in inhibitor treatment. The expression of the crucial members in the pathway of MC-4 cells, including glycoprotein 130 (GP130), JAK1, JAK2, STAT3, p-STAT3, suppressor of cytokine signaling SOCS1 and SOCS3, was detected by western blotting. pPeOp exhibited promising anticancer effect in the xenograft nude mice model, established by STAT3 knock down gastric cancer cells.Thus, JAK/STAT3 inhibition partially contributed to the anticancer effect of pPeOp, which may serve as a novel strategy for gastric cancer.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1960385.

Immune Cell Landscape in Gastric Cancer

Background

The tumor-infiltrating immune cells are closely associated with the prognosis of gastric cancer (GC). This article is aimed at determining the composition change of immune cells and immune regulatory factors in GC and normal tissues, depicting their prognosis value in GC, and revealing the relationship between them and GC clinical parameters.

Methods

We used CIBERSORT to calculate the proportion of 22 immune cells in the GC or normal tissues; a t-test was applied to assess the expression difference of immune cells and immune regulatory factors in normal and GC tissues. The relationship of the immune cells, immune regulatory factors, and GC patients' clinical characteristics was assessed by univariate analysis.

Results

In this study, we found that the proportion of macrophages increased, while plasma cells and monocytes decreased in GC tissues. In these immune fractions, Tregs and naïve B cells were found to be correlated with GC patients' prognosis. Interestingly, the expression of immune regulatory factors was ambiguous with their classical function in GC tissues. For example, TIM-3, FOXP3, and CMTM6 were overexpressed, while CD27 and PD-1 were underexpressed in GC tissues. We also found that IDO1, PD-1, TIGIT, and TIM-3 were highly expressed in high-grade GC tissues, the HERC2 expression level was related to patients' gender, and the TIGIT expression level was sensitive to targeted therapy. Furthermore, our results suggested that the infiltration of Tregs and naive B cells was strongly correlated with the T stage, radiation therapy, targeted molecular therapy, and the expression levels of TIM-3 and FOXP3 in GC.

Conclusion

The expression pattern of tumor-infiltrating immune cells and immune regulatory factors was systematically depicted in the GC tumor microenvironment, indicating that individualized treatment based on the tumor-infiltrating immune cells and immune regulatory factors may be beneficial to GC patients.

Risk factors for Epstein Barr virus-associated cancers: a systematic review, critical appraisal, and mapping of the epidemiological evidence

BACKGROUND

Epstein Barr Virus (EBV) infects 90%-95% of all adults globally and causes ~ 1% of all cancers. Differing proportions of Burkitt's lymphoma (BL), gastric carcinoma (GC), Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC) are associated with EBV. We sought to systematically review the global epidemiological evidence for risk factors that (in addition to EBV) contribute to the development of the EBV-associated forms of these cancers, assess the quality of the evidence, and compare and contrast the cancers.

METHODS

MEDLINE, Embase and Web of Science were searched for studies of risk factors for EBV-associated BL, GC, HL and NPC without language or temporal restrictions. Studies were excluded if there was no cancer-free comparator group or where analyses of risk factors were inadequately documented. After screening and reference list searching, data were extracted into standardised spreadsheets and quality assessed. Due to heterogeneity, a narrative synthesis was undertaken.

RESULTS

9916 hits were retrieved. 271 papers were retained: two BL, 24 HL, one GC and 244 NPC. The majority of studies were from China, North America and Western Europe. Risk factors were categorised as dietary, environmental/non-dietary, human genetic, and infection and clinical. Anti-EBV antibody load was associated with EBV-associated GC and BL. Although the evidence could be inconsistent, HLA-A alleles, smoking, infectious mononucleosis and potentially other infections were risk factors for EBV-associated HL. Rancid dairy products; anti-EBV antibody and EBV DNA load; history of chronic ear, nose and/or throat conditions; herbal medicine use; family history; and human genetics were risk factors for NPC. Fresh fruit and vegetable and tea consumption may be protective against NPC.

CONCLUSIONS

Many epidemiological studies of risk factors in addition to EBV for the EBV-associated forms of BL, GC, HL and NPC have been undertaken, but there is a dearth of evidence for GC and BL. Available evidence is of variable quality. The aetiology of EBV-associated cancers likely results from a complex intersection of genetic, clinical, environmental and dietary factors, which is difficult to assess with observational studies. Large, carefully designed, studies need to be strategically undertaken to harmonise and clarify the evidence.

REGISTRATION

PROSPERO CRD42017059806.

Positive Status of Epstein-Barr Virus as a Biomarker for Gastric Cancer Immunotherapy: A Prospective Observational Study

Immunotherapy has exhibited promising but controversial results in gastric cancer; determining criteria for choosing the appropriate target population is still problematic. Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) exhibits distinctive genomic aberrations and clinicopathologic features, the positive status of EBV is a potential biomarker. We prospectively recruited 9 patients who were diagnosed with stage-IV EBVaGC, and all of the patients were treated by immune-checkpoint inhibitors. The median age of the patients was 62 years old. The clinicopathologic characteristics demonstrated a male predominance and poor differentiation status of EBVaGC. Lymph nodes were demonstrated to represent the most common metastatic site. Immunochemistry and polymerase chain reaction analysis revealed that all of the patients were proficient mismatch repair, and microsatellite instability-stable and programmed cell death-ligand 1 were detected in 7 patients. Three patients with positive programmed cell death-ligand 1 showed partial response, 5 patients showed stable disease, 1 patient without measurable lesion showed decreasing ascites and tumor marker level after immunotherapy. The longest duration of response was 18 months by the time of the last follow-up. EBVaGC exhibits distinctive clinicopathologic characteristics, and EBV-positive status may be a potential biomarker for gastric cancer immunotherapy.

Nucleolin-Sle A Glycoforms as E-Selectin Ligands and Potentially Targetable Biomarkers at the Cell Surface of Gastric Cancer Cells

BACKGROUND

Gastric cancer (GC) is a major health burden worldwide, with half of patients developing metastases within 5 years after treatment, urging novel biomarkers for diagnosis and efficient therapeutic targeting. Sialyl-Lewis A (SLeA), a terminal glycoepitope of glycoproteins and glycolipids, offers tremendous potential towards this objective. It is rarely expressed in healthy tissues and blood cells, while it is present in highly metastatic cell lines and metastases. SLeA is also involved in E-selectin mediated metastasis, making it an ideal target to control disease dissemination.

METHODS AND RESULTS

To improve cancer specificity, we have explored the SLeA-glycoproteome of six GC cell models, with emphasis on glycoproteins showing affinity for E-selectin. A novel bioinformatics-assisted algorithm identified nucleolin (NCL), a nuclear protein, as a potential targetable biomarker potentially involved in metastasis. Several immunoassays, including Western blot and in situ proximity ligation reinforced the existence of cell surface NCL-SLeA glycoforms in GC. The NCL-SLeA glycophenotype was associated with decreased survival and was not reflected in relevant healthy tissues.

CONCLUSIONS

NCL-SLeA is a biomarker of poor prognosis in GC holding potential for precise cancer targeting. This is the first report describing SLeA in preferentially nuclear protein, setting a new paradigm for cancer biomarkers discovery and targeted therapies.

Early intravenous administration of nutritional support (IVANS) in metastatic gastric cancer patients at nutritional risk, undergoing first-line chemotherapy: study protocol of a pragmatic, randomized, multicenter, clinical trial

Background

Malnutrition is common in cancer patients, particularly in those affected by gastrointestinal malignancies, and negatively affects treatment tolerance, survival, functional status, and quality of life (QoL). Nutritional support, including supplemental parenteral nutrition (SPN), has been recommended at the earliest opportunity in malnourished cancer patients. The limited available evidence on the efficacy of SPN in gastrointestinal cancer patients is positive, particularly with regards to QoL, body composition, and energy intake, but the evidence on survival is still scanty. Furthermore, studies regarding the early administration of SPN in combination with nutritional counseling from the beginning of first-line chemotherapy (CT) are lacking. We hypothesize that early systematic SPN in combination with nutritional counseling (NC), compared with NC alone, can benefit patients with previously untreated metastatic gastric cancer at nutritional risk undergoing first-line CT.

Methods

The aim of this pragmatic, multicenter, randomized (1:1), parallel-group, open-label, controlled clinical trial is to evaluate the efficacy in terms of survival, weight maintenance, body composition, QoL and feasibility of cancer therapy of early systematic SNP. This is in combination with NC, compared with NC alone, in treatment-naïve metastatic gastric cancer patients at nutritional risk undergoing first-line CT.

Discussion

Malnutrition in oncology remains an overlooked problem. Although the importance of SPN in gastrointestinal cancer patients has been acknowledged, no studies have yet evaluated the efficacy of early SPN in metastatic gastric patients undergoing CT. The present study, which guarantees the early provision of nutritional assessment and support to all the enrolled patients in accordance with the recent guidelines and recommendations, could represent one of the first proofs of the clinical effectiveness of early intensive nutritional support in cancer patients undergoing CT. This study could stimulate further large randomized trials in different cancer types, potentially resulting in the improvement of supportive care quality.

Trial registration

This study is registered on ClinicalTrials.gov: NCT03949907.

Prognostic value of non-invasive serum Cytokeratin 18 detection in gastrointestinal cancer: a meta-analysis

Background: Gastrointestinal cancer is one of the most common neoplasms. Cytokeratin 18(CK18) is widely expressed in many different organs and cancers. Emerging data suggested conflicting results about the role of CK18 during carcinogenesis. The aim of this study is to systematically review the prognostic value of circulating CK18 (M65) and caspase-Cleaved CK18 (M30) in digestive cancers.

Materials and Methods: We searched major database for manuscripts reporting the effect of pretreatment CK18 on survival of digestive cancer patients. Revman5.3 and R were the software used for analysis. Pooled multivariable-adjusted hazard ratios (HR) for overall survival (OS) were calculated in all patients and many different subgroup analyses by stratifying on tumor type, metastasis stage, and ethnicity.

Results: 11 original studies were included for analysis. A low level of M30 and M65 were shown to be a protective factor for all cancer patients (HR 0.49, 95%CI 0.33-0.73, P=0.0003; HR 0.48, 95% CI 0.32-0.70, P =0.0001, respectively). The low M30 remained to be a protective factor for metastasized cancer patients while M65 had no statistically significant correlation with prognosis.

Conclusions: Non-invasive total and cleaved CK18 level detection by ELISA could be potentially a useful predictor of prognosis of digestive cancer patients. Further studies are warranted to investigate the molecular mechanisms of CK18.