Integrated DNA and RNA sequencing reveals early drivers involved in metastasis of gastric cancer

Landscape of four different stages of human gastric cancer revealed by single-cell sequencing

BACKGROUND

Gastric cancer (GC) poses a substantial risk to human health due to its high prevalence and mortality rates. Nevertheless, current therapeutic strategies remain insufficient. Single-cell RNA sequencing (scRNA-seq) offers the potential to provide comprehensive insights into GC pathogenesis.

AIM

To explore the distribution and dynamic changes of cell populations in the GC tumor microenvironment using scRNA-seq techniques.

METHODS

Cancerous tissues and paracancerous tissues were obtained from patients diagnosed with GC at various stages (I, II, III, and IV). Single-cell suspensions were prepared and analyzed using scRNA-seq to examine transcriptome profiles and cell-cell interactions. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry were applied for measuring the expression of cluster of differentiation (CD) 2, CD3D, CD3E, cytokeratin 19, cytokeratin 8, and epithelial cell adhesion molecules.

RESULTS

Transcriptome data from 73645 single cells across eight tissues of four patients were categorized into 25 distinct cell clusters, representing 10 different cell types. Variations were observed in these cell type distribution. The adjacent epithelial cells in stages II and III exhibited a degenerative trend. Additionally, the quantity of CD4 T cells and CD8 T cells were evidently elevated in cancerous tissues. Interaction analysis displayed a remarkable increase in interaction between B cells and other mast cells in stages II, III, and IV of GC. These findings were further validated through qRT-PCR and flow cytometry, demonstrating elevated T cells and declined epithelial cells within the cancerous tissues.

CONCLUSION

This study provides a comprehensive analysis of cell dynamics across GC stages, highlighting key interactions within the tumor microenvironment. These findings offer valuable insights for developing novel therapeutic strategies.

Preoperative liquid biopsy transcriptomic panel for risk assessment of lymph node metastasis in T1 gastric cancer

BACKGROUND

The increasing incidence of early-stage T1 gastric cancer (GC) underscores the need for accurate preoperative risk stratification of lymph node metastasis (LNM). Current pathological assessments often misclassify patients, leading to unnecessary radical surgeries.

METHODS

Through analysis of transcriptomic data from public databases and T1 GC tissues, we identified a 4-mRNA panel (SDS, TESMIN, NEB, and GRB14). We developed and validated a Risk Stratification Assessment (RSA) model combining this panel with clinical features using surgical specimens (training cohort: n = 218; validation cohort: n = 186), gastroscopic biopsies (n = 122), and liquid biopsies (training cohort: n = 147; validation cohort: n = 168).

RESULTS

The RSA model demonstrated excellent predictive accuracy for LNM in surgical specimens (training AUC = 0.890, validation AUC = 0.878), gastroscopic biopsies (AUC = 0.928), and liquid biopsies (training AUC = 0.873, validation AUC = 0.852). This model significantly reduced overtreatment rates from 83.9 to 44.1% in tissue specimens and from 84.4 to 56.0% in liquid biopsies. The 4-mRNA panel showed specificity for T1 GC compared to other gastrointestinal cancers (P < 0.001).

CONCLUSIONS

We developed and validated a novel liquid biopsy-based RSA model that accurately predicts LNM in T1 GC patients. This non-invasive approach could significantly reduce unnecessary surgical interventions and optimize treatment strategies for high-risk T1 GC patients.

LncRNA FIRRE drives gastric cancer progression via ZFP64-mediated TUBB3 promoter activation

Gastric cancer is a common global malignancy that requires detailed study of its development mechanisms. Although LncRNA FIRRE is known to play a crucial role in the progression and treatment resistance of several cancers, its effect on gastric cancer is not well understood. This study confirms the impact of FIRRE on the malignant behavior of gastric cancer. Using RNA-sequencing, dual luciferase reporter assay, RIP and CHIP, we identified transcription factors and target genes linked to FIRRE. Elevated FIRRE expression in gastric cancer correlates with worse patient prognosis and promotes gastric cancer proliferation, migration, and invasion both in vitro and in vivo. FIRRE regulates the TUBB3 gene, facilitating gastric cancer progression by activating the TUBB3 promoter in vitro. ZFP64 is the transcription factor for TUBB3, activating its promoter and binding specifically with FIRRE. Reducing ZFP64 disrupts FIRRE's positive regulation of TUBB3 in vitro and in vivo. This study shows FIRRE promotes gastric cancer progression by binding to ZFP64 and activating the TUBB3 promoter.

Epstein-Barr Virus and gastric carcinoma pathogenesis with emphasis on underlying epigenetic mechanisms

Gastric cancer (GC) remains one of the top causes of cancer-related mortality around the world. The pathogenesis of GC is attributed to lifestyle, family history, genetic mutations, epigenetic alterations, as well as infectious agents such as Epstein-Barr Virus (EBV). EBV, a ubiquitous human gamma herpes virus, with latent asymptomatic infection in more than 95% of the world's population, is able to infect through the oral epithelium. EBV is described as the first virus found in human neoplastic, when it was detected in Burkitt lymphoma tumor biopsy. Nowadays this virus is considered to be involved in various human malignancies such as GC. Despite comprehensive efforts and immense studies, the main underlying mechanism is not well described as there are crucial contradictions regarding the presence of this virus and the prognosis of the disease. Immunological alterations, genetic mutations, and epigenetic modifications are among the most important criteria presented in EBV- associated gastric cancer (EBVaGC), leading to its consideration as a separate subtype with unique clinical, histological, biochemical, and genetic characteristics. The current study aimed to review the association between EBV and GC with an emphasis on the role of epigenetic modifications in the suppression or progression of carcinogenesis. To put all findings in a nutshell, several genes and chromatin mutations, promoter hypermethylation and subsequent silencing of related genes, and histone modifications and aberrant micro RNAs (miRNAs) expression were considered as the major altered mechanisms in the pathogenesis of EBVaGC, most of which able to be suggested as therapeutic targets. However, the current knowledge appeared to be imperfect, hence further studies are encouraged.

Molecular evolution of intestinal-type early gastric cancer according to Correa cascade

Early screening is crucial for the prevention of intestinal-type gastric cancer. The objective of the current study was to ascertain molecular evolution of intestinal-type gastric cancer according to the Correa cascade for the precise gastric cancer screening. We collected sequential lesions of the Correa cascade in the formalin-fixed and paraffin-embedded endoscopic submucosal dissection-resected specimens from 14 Chinese patients by microdissection, and subsequently determined the profiles of somatic aberrations during gastric carcinogenesis using the whole exome sequencing, identifying multiple variants at different Correa stages. The results showed that TP53, PCLO, and PRKDC were the most frequently mutated genes in the early gastric cancer (EGC). A high frequency of TP53 alterations was found in low-grade intraepithelial neoplasia (LGIN), which further increased in high-grade intraepithelial neoplasia (HGIN) and EGC. Intestinal metaplasia (IM) had no significant correlation with EGC in terms of mutational spectra, whereas both LGIN and HGIN showed higher genomic similarities to EGC, compared with IM. Based on Jaccard similarity coefficients, three evolutionary models were further constructed, and most patients showed linear progression from LGIN to HGIN, ultimately resulting in EGC. The ECM-receptor interaction pathway was revealed to be involved in the linear evolution. Additionally, the retrospective validation study of 39 patients diagnosed with LGIN indicated that PRKDC mutations, in addition to TP53 mutations, may drive LGIN progression to HGIN or EGC. In conclusion, the current study unveils the genomic evolution across the Correa cascade of intestinal-type gastric cancer, elucidates the underlying molecular mechanisms of gastric carcinogenesis, and provides some evidence for potential personalized gastric cancer surveillance.

A prospective phase II single-arm study and predictive factor analysis of irinotecan as third-line treatment in patients with metastatic gastric cancer

Background

Currently, there is no recommended standard third-line chemotherapy for metastatic gastric cancer.

Objectives

In this study, we aimed to evaluate irinotecan's efficacy and safety in treating metastatic gastric cancer after the failure of first- and second-line chemotherapy.

Design

Prospective single-arm, two-center, phase II trial.

Methods

Patients were aged 18-70 years, with histologically confirmed gastric adenocarcinoma and an Eastern Cooperative Oncology Group performance status of 0-1, progressed during or within 3 months following the last administration of second-line chemotherapy and had no other severe hematologic, cardiac, pulmonary, hepatic, or renal functional abnormalities or immunodeficiency diseases. Eligible patients received 28-day cycles of irinotecan (180 mg/m2 intravenously, days 1 and 15) and were assessed according to the RECIST 1.1 criteria every two cycles. Patients who discontinued treatment for any reason were followed up every 2 months until death. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and toxicity.

Results

A total of 98 eligible patients were enrolled in this study. In the intention-to-treat population, the median OS was 7.17 months, the median PFS was 3.47 months, and the ORR and DCR were 4.08% and 47.96%, respectively. In the per-protocol population, the median OS was 7.77 months, the median PFS was 3.47 months, and the ORR and DCR were 4.82% and 50.60%, respectively. The incidence of grade 3 or 4 hematological and non-hematological toxicities was 19.4%, and none of the patients died owing to adverse events. Cox regression analysis revealed neutropenia and baseline thrombocyte levels were independently correlated with PFS and OS.

Conclusion

Irinotecan monotherapy is an efficient, well-tolerated, and economical third-line treatment for patients with metastatic gastric cancer as a third-line treatment.

Trial registration

ClinicalTrials.gov identifier: NCT02662959.

Multi-omics Combined with Machine Learning Facilitating the Diagnosis of Gastric Cancer

Gastric cancer (GC) is a highly intricate gastrointestinal malignancy. Early detection of gastric cancer forms the cornerstone of precision medicine. Several studies have been conducted to investigate early biomarkers of gastric cancer using genomics, transcriptomics, proteomics, and metabolomics, respectively. However, endogenous substances associated with various omics are concurrently altered during gastric cancer development. Furthermore, environmental exposures and family history can also induce modifications in endogenous substances. Therefore, in this study, we primarily investigated alterations in DNA mutation, DNA methylation, mRNA, lncRNA, miRNA, circRNA, and protein, as well as glucose, amino acid, nucleotide, and lipid metabolism levels in the context of GC development, employing genomics, transcriptomics, proteomics, and metabolomics. Additionally, we elucidate the impact of exposure factors, including HP, EBV, nitrosamines, smoking, alcohol consumption, and family history, on diagnostic biomarkers of gastric cancer. Lastly, we provide a summary of the application of machine learning in integrating multi-omics data. Thus, this review aims to elucidate: i) the biomarkers of gastric cancer related to genomics, transcriptomics, proteomics, and metabolomics; ii) the influence of environmental exposure and family history on multiomics data; iii) the integrated analysis of multi-omics data using machine learning techniques.

Genomic and evolutionary characteristics of metastatic gastric cancer by routes

BACKGROUND

In gastric cancer (GC) patients, metastatic progression through the lymphatic, hematogenous, peritoneal, and ovarian routes, is the ultimate cause of death. However, the genomic and evolutionary characteristics of metastatic GC have not been widely evaluated.

METHODS

Whole-exome sequencing data were analyzed for 99 primary and paired metastatic gastric cancers from 15 patients who underwent gastrectomy and metastasectomy.

RESULTS

Hematogenous metastatic tumors were associated with increased chromosomal instability and de novo gain/amplification in cancer driver genes, whereas peritoneal/ovarian metastasis was linked to sustained chromosomal stability and de novo somatic mutations in driver genes. The genomic distance of the hematogenous and peritoneal metastatic tumors was found to be closer to the primary tumors than lymph node (LN) metastasis, while ovarian metastasis was closer to LN and peritoneal metastasis than the primary tumor. Two migration patterns for metastatic GCs were identified; branched and diaspora. Both molecular subtypes of the metastatic tumors, rather than the primary tumor, and their migration patterns were related to patient survival.

CONCLUSIONS

Genomic characteristics of metastatic gastric cancer is distinctive by routes and associated with patients' prognosis along with genomic evolution pattenrs, indicating that both primary and metastatic gastric cancers require genomic evaluation.

Comprehensive bioinformatics and experimental analysis of SH3PXD2B reveals its carcinogenic effect in gastric carcinoma

AIMS

We aim to explore the possibility and mechanism of SH3PXD2B as a reliable biomarker for gastric cancer (GC).

MAIN METHODS

We used public databases to analyze the molecular characteristics and disease associations of SH3PXD2B, and KM database for prognostic analysis. The TCGA gastric cancer dataset was used for single gene correlation, differential expression, functional enrichment and immunoinfiltration analysis. SH3PXD2B protein interaction network was constructed by the STRING database. And the GSCALite database was used to explore sensitive drugs and perform SH3PXD2B molecular docking. The impact of SH3PXD2B silencing and over-expression by lentivirus transduction on the proliferation and invasion of human GC HGC-27 and NUGC-3 cells was determined.

KEY FINDINGS

The high expression of SH3PXD2B in gastric cancer was related to the poor prognosis of patients. It may affect the progression of gastric cancer by forming a regulatory network with FBN1, ADAM15 and other molecules, and the mechanism may involve regulating the infiltration of Treg, TAM and other immunosuppressive cells. The cytofunctional experiments verified that it significantly promoted the proliferation and migration of gastric cancer cells. In addition, we found that some drugs were sensitive to the expression of SH3PXD2B such as sotrastaurin, BHG712 and sirolimus, and they had strong molecular combination of SH3PXD2B, which may provide guidance for the treatment of gastric cancer.

SIGNIFICANCE

Our study strongly suggests that SH3PXD2B is a carcinogenic molecule that can be used as a biomarker for GC detection, prognosis, treatment design, and follow-up.

LncRNA LINC01094 Promotes Cells Proliferation and Metastasis through the PTEN/AKT Pathway by Targeting AZGP1 in Gastric Cancer

Long noncoding RNAs (lncRNAs) were recently reported to play an essential role in multiple cancer types. Herein, through next-generation sequencing, we screened metastasis-driving molecules by using tissues from early-stage gastric cancer (GC) patients with lymph node metastasis, and we identified a lncRNA LINC01094, which was associated with the metastasis of GC. According to the clinical data from the TCGA, GSE15459, and GSE62254 cohorts, the high expression of LINC01094 was associated with an unfavorable prognosis. Moreover, 106 clinical GC and paired normal samples were collected, and the qRT-PCR results showed that the high expression of LINC01094 was associated with high T and N stages and a poor prognosis. We found that LINC01094 promotes the proliferation and metastasis of GC in vitro and in vivo. AZGP1 was found as the protein-binding partner of LINC01094 by using RNA pulldown and RNA-binding protein immunoprecipitation (RIP) assays. LINC01094 antagonizes the function of AZGP1, downregulates the expression of PTEN, and further upregulates the AKT pathway. Collectively, our results suggested that LINC01094 might predict the prognosis of GC patients and become the therapy target for GC.

Integrating multi-type aberrations from DNA and RNA through dynamic mapping gene space for subtype-specific breast cancer driver discovery

Driver event discovery is a crucial demand for breast cancer diagnosis and therapy. In particular, discovering subtype-specificity of drivers can prompt the personalized biomarker discovery and precision treatment of cancer patients. Still, most of the existing computational driver discovery studies mainly exploit the information from DNA aberrations and gene interactions. Notably, cancer driver events would occur due to not only DNA aberrations but also RNA alternations, but integrating multi-type aberrations from both DNA and RNA is still a challenging task for breast cancer drivers. On the one hand, the data formats of different aberration types also differ from each other, known as data format incompatibility. On the other hand, different types of aberrations demonstrate distinct patterns across samples, known as aberration type heterogeneity. To promote the integrated analysis of subtype-specific breast cancer drivers, we design a "splicing-and-fusing" framework to address the issues of data format incompatibility and aberration type heterogeneity simultaneously. To overcome the data format incompatibility, the "splicing-step" employs a knowledge graph structure to connect multi-type aberrations from the DNA and RNA data into a unified formation. To tackle the aberration type heterogeneity, the "fusing-step" adopts a dynamic mapping gene space integration approach to represent the multi-type information by vectorized profiles. The experiments also demonstrate the advantages of our approach in both the integration of multi-type aberrations from DNA and RNA and the discovery of subtype-specific breast cancer drivers. In summary, our "splicing-and-fusing" framework with knowledge graph connection and dynamic mapping gene space fusion of multi-type aberrations data from DNA and RNA can successfully discover potential breast cancer drivers with subtype-specificity indication.

Molecular mechanism and potential therapeutic targets of liver metastasis from gastric cancer

Gastric cancer (GC) is characterized by high invasion and poor prognosis. The occurrence of liver metastasis seriously affects advanced GC prognosis. In recent years, great progress has been made in the field of GC liver metastasis. The abnormal expression of related genes leads to the occurrence of GC liver metastasis through metastasis cascades. The changes in the liver microenvironment provide a pre-metastasis condition for GC cells to colonize and grow. The development of several potential therapeutic targets might provide new therapeutic strategies for its treatment. Therefore, we reviewed the regulatory mechanism of abnormal genes mediating liver metastasis, the effect of liver resident cells on liver metastasis, and potential therapeutic targets, hoping to provide a novel therapeutic option to improve the quality of life and prognosis of GC patients with liver metastasis.

Transcriptomic and Proteomic Profiles for Elucidating Cisplatin Resistance in Head-and-Neck Squamous Cell Carcinoma

To identify the novel genes involved in chemoresistance in head and neck squamous cell carcinoma (HNSCC), we explored the expression profiles of the following cisplatin (CDDP) resistant (R) versus parental (sensitive) cell lines by RNA-sequencing (RNA-seq): JHU029, HTB-43 and CCL-138. Using the parental condition as a control, 30 upregulated and 85 downregulated genes were identified for JHU029-R cells; 263 upregulated and 392 downregulated genes for HTB-43-R cells, and 154 upregulated and 68 downregulated genes for CCL-138-R cells. Moreover, we crossed-checked the RNA-seq results with the proteomic profiles of HTB-43-R (versus HTB-43) and CCL-138-R (versus CCL-138) cell lines. For the HTB-43-R cells, 21 upregulated and 72 downregulated targets overlapped between the proteomic and transcriptomic data; whereas in CCL-138-R cells, four upregulated and three downregulated targets matched. Following an extensive literature search, six genes from the RNA-seq (CLDN1, MAGEB2, CD24, CEACAM6, IL1B and ISG15) and six genes from the RNA-seq and proteomics crossover (AKR1C3, TNFAIP2, RAB7A, LGALS3BP, PSCA and SSRP1) were selected to be studied by qRT-PCR in 11 HNSCC patients: six resistant and five sensitive to conventional therapy. Interestingly, the high MAGEB2 expression was associated with resistant tumours and is revealed as a novel target to sensitise resistant cells to therapy in HNSCC patients.