Long non-coding RNAs and gastric cancer: An update of potential biomarkers and therapeutic applications

The emerging role of long non-coding RNA SOX2-OT in cancers and non-malignant diseases

SOX2 overlapping transcript (SOX2-OT) is a long non-coding RNA located at chromosome 3q26.33 in humans. Convincing data confirm that SOX2-OT is evolutionarily conserved and plays a significant role in various malignant and non-malignant diseases. In most cancers, the upregulation of SOX2-OT acts as an oncogenic factor, strongly correlating with tumor risk, adverse clinicopathological features, and poor prognosis. Mechanistically, SOX2-OT is regulated by seven transcription factors and influences cellular behavior by modulating SOX2 expression, competitively binding 20 types of miRNAs, stabilizing protein expression, or promoting protein ubiquitination. It also participates in epigenetic modifications and activates multiple signaling pathways to regulate cancer cell proliferation, apoptosis, migration, invasion, autophagy, immune evasion, and resistance to chemotherapy/targeted therapies. Additionally, SOX2-OT triggers apoptosis, oxidative stress, and inflammatory responses, contributing to neurodevelopmental disorders, cardiovascular diseases, and diabetes-related conditions. Genetic polymorphisms of SOX2-OT have also been linked to breast cancer, gastric cancer, recurrent miscarriage, sepsis, and eating disorders in patients with bipolar disorder. This review provides an overview of recent research progress on SOX2-OT in human diseases, highlights its substantial potential as a prognostic and diagnostic biomarker, and explores its future clinical applications.

LncRNAs orchestration of gastric cancer - particular emphasis on the etiology, diagnosis, and treatment resistance

Gastric cancer (GC) remains a major public health challenge worldwide. Long non-coding RNAs (lncRNAs) play important roles in the development, progression, and resistance to the treatment of GC, as shown by recent developments in molecular characterization. Still, an in-depth investigation of the lncRNA landscape in GC is absent. However, The objective of this systematic review is to evaluate our present understanding of the role that lncRNA dysregulation plays in the etiology of GC and treatment resistance, with a focus on the underlying mechanisms and clinical implications. Research that described the functions of lncRNA in angiogenesis, stemness, epigenetics, metastasis, apoptosis, development, and resistance to key treatments was given priority. In GC, it has been discovered that a large number of lncRNAs, including MALAT1, HOTAIR, H19, and ANRIL, are aberrantly expressed and are connected with disease-related outcomes. Through various methods such as chromatin remodeling, signal transduction pathways, and microRNA sponging, they modulate hallmark cancer capabilities. Through the activation of stemness programs, epithelial-mesenchymal transition (EMT), and survival signaling, LncRNAs also control resistance to immunotherapy, chemotherapy, and targeted therapies. By clarifying their molecular roles further, we may be able to identify new treatment targets and ways to overcome resistance. This article aims to explore the interplay between lncRNAs, and GC. Specifically, the focus is on understanding how lncRNAs contribute to the etiology of GC and influence treatment resistance in patients with this disease.

Activation of the G Protein-Coupled Bile Acid Receptor TGR5 Modulates the HCP5/miR-139-5p/DDIT4 Axis to Antagonize Cervical Cancer Progression

A growing body of evidence indicates that the G protein-coupled bile acid receptor, TGR5, plays a critical role in multiple physiological processes ranging from metabolic disorders to cancers. However, the biological functions of TGR5 in cervical cancer (CC) have not been elucidated. Here, using TGR5 knockout mice, we found that a deficiency of TGR5 leads to greater sensitivity to the progression of cervical inflammation. Activation of TGR5 by its specific ligands significantly attenuated the malignant behavior of CC cells. In addition, we found that TGR5 can negatively modulate the expression of lncRNA HCP5 by blocking its transcription activation when mediated by p65. HCP5 was highly expressed in CC tissues, which was positively correlated with the poor prognosis of CC patients. HCP5 knockdown notably restrained CC cell proliferation, colony formation, and migration in vitro, and inhibited tumor growth in vivo. Furthermore, HCP5 can function as the molecular sponge for miR-139-5p to upregulate DNA damage-induced transcript 4 (DDIT4) in CC cells. Murine xenograft studies demonstrated that TGR5 suppressed the tumor formation of CC cells and downregulated HCP5 and DDIT4 while increasing miR-139-5p in the xenografts. Taken together, these findings, for the first time, indicate that TGR5 inhibits CC progression by regulating the HCP5/miR-139-5p/DDIT4 axis, suggesting that it may represent a novel and potent target for CC treatment.

Unraveling the influence of LncRNA in gastric cancer pathogenesis: a comprehensive review focus on signaling pathways interplay

Gastric cancers (GCs) are among the most common and fatal malignancies in the world. Despite our increasing understanding of the molecular mechanisms underlying GC, further biomarkers are still needed for more in-depth examination, focused prognosis, and treatment. GC is one among the long non-coding RNAs, or lncRNAs, that have emerged as key regulators of the pathophysiology of cancer. This comprehensive review focuses on the diverse functions of long noncoding RNAs (lncRNAs) in the development of GC and their interactions with important intracellular signaling pathways. LncRNAs affect GC-related carcinogenic signaling cascades including pathways for EGFR, PI3K/AKT/mTOR, p53, Wnt/β-catenin, JAK/STAT, Hedgehog, NF-κB, and hypoxia-inducible factor. Dysregulated long non-coding RNA (lncRNA) expression has been associated with multiple characteristics of cancer, such as extended growth, apoptosis resistance, enhanced invasion and metastasis, angiogenesis, and therapy resistance. For instance, lncRNAs such as HOTAIR, MALAT1, and H19 promote the development of GC via altering these pathways. Beyond their main roles, GC lncRNAs exhibit potential as diagnostic and prognostic biomarkers. The overview discusses CRISPR/Cas9 genome-modifying methods, antisense oligonucleotides, small molecules, and RNA interference as potential therapeutic approaches to regulate the expression of long noncoding RNAs (lncRNAs). An in-depth discussion of the intricate functions that lncRNAs play in the development of the majority of stomach malignancies is provided in this review. It provides the groundwork for future translational research in lncRNA-based whole processes toward GC by highlighting their carcinogenic effects, regulatory roles in significant signaling cascades, and practical scientific uses as biomarkers and therapeutic targets.

Expression of Pivotal Long Non-coding RNAs Implicated in Gastric Cancer: A Bioinformatic and Clinical Study

Gastric cancer (GC) is a prominent public health issue and ranks as the third most prevalent cause of cancer-related mortality on a global scale. The role of long non-coding RNAs (lncRNAs) in cancer is not yet fully understood, particularly in relation to GC development. The objective of this study was to examine the expression levels of lncRNAs in GC tissues using a bioinformatics-based ranking approach. A bioinformatics methodology was employed to prioritize lncRNAs that are hypothesized to play a role in GC tumorigenesis. Moreover, a selection was made for experimental validation of the highest-ranked lncRNAs, which include HCG18, OIP5-AS1, FGD5-AS1, and NORAD. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) was employed to confirm the results obtained from bioinformatics analysis in a total of 35 GC samples and their corresponding adjacent non-tumoral samples. Receiver operating characteristic (ROC) curves and the corresponding area under the ROC curve (AUC) were utilized to evaluate the diagnostic efficacy of the lncRNAs. The bioinformatics analysis revealed that the lncRNA HCG18 is the highest-ranked lncRNA associated with GC. Furthermore, the expression levels of HCG18, OIP5-AS1, FGD5-AS1, and NORAD were found to be significantly elevated in GC samples when compared to adjacent non-tumoral samples. The calculated values for the AUC of HCG18, OIP5-AS1, FGD5-AS1, and NORAD were 0.80, 0.74, 0.73, and 0.71, respectively. The results of the study indicate that the lncRNAs HCG18, OIP5-AS1, FGD5-AS1, and NORAD may play a role in the development of GC. Additionally, the present study revealed that utilizing bioinformatic techniques can prove to be a highly effective strategy in identifying potential lncRNAs pertinent to the progression of GC.

Genome-wide investigation of lncRNAs revealed their tight association with gastric cancer

BACKGROUND

Gastric cancer (GC) is a significant health issue globally, ranking as the fifth most common cancer with over 10,000 new cases reported annually. Long non-coding RNA (lncRNA) has emerged as a critical player in cellular functions, influencing GC's development, growth, metastasis, and prognosis. However, our understanding of lncRNA's role in the pathogenesis of GC remains limited. Therefore, it is particularly important to explore the relationship between lncRNA and gastric cancer.

METHODS

we conducted a comprehensive analysis of RNA sequencing data from the GEO database and stomach adenocarcinoma (STAD) data from the TCGA database to identify lncRNAs that exhibit altered expression levels in GC and the mechanisms underlying lncRNA-mediated transcription and post-transcriptional regulation were explored.

RESULTS

This study uncovered 94 lncRNAs with differential expression and, through co-expression analysis, linked these to 1508 differentially expressed genes (DEGs). GO functional enrichment analysis highlighted that these DEGs are involved in critical pathways, such as cell adhesion and the positive regulation of cell migration. By establishing a lncRNA-miRNA-mRNA regulatory network, we found that the ceRNA mechanism, particularly involving RP11-357H14.17 and CTD-2377D24.4, could play a role in GC progression. Experimental validation of selected differentially expressed lncRNAs and mRNAs (including RP11-357H14.17-CLDN1, BBOX1, TRPM2-AS, CLDN1, PLAU, HOXB7) confirmed the RNA-seq results.

CONCLUSIONS

Overall, our findings highlight the critical role of the lncRNA-mRNA regulatory network in the development and progression of GC, offering potential biomarkers for diagnosis and targets for innovative treatment strategies.

Identification of Key lncRNAs Associated with Immune Infiltration and Prognosis in Gastric Cancer

Long non-coding RNAs (lncRNAs), as promising novel biomarkers for cancer treatment and prognosis, can function as tumor suppressors and oncogenes in the occurrence and development of many types of cancer, including gastric cancer (GC). However, little is known about the complex regulatory system of lncRNAs in GC. In this study, we systematically analyzed lncRNA and miRNA transcriptomic profiles of GC based on bioinformatics methods and experimental validation. An lncRNA-miRNA interaction network related to GC was constructed, and the nine crucial lncRNAs were identified. These 9 lncRNAs were found to be associated with the prognosis of GC patients by Cox proportional hazards regression analysis. Among them, the expression of lncRNA SNHG14 can affect the survival of GC patients as a potential prognostic marker. Moreover, it was shown that SNHG14 was involved in immune-related pathways and significantly correlated with immune cell infiltration in GC. Meanwhile, we found that SNHG14 affected immune function in many cancers, such as breast cancer and esophageal carcinoma. Such information revealed that SNHG14 may serve as a potential target for cancer immunotherapy. As well, our study could provide practical and theoretical guiding significance for clinical application of non-coding RNAs.

LINC00355 promotes gastric carcinogenesis by scaffolding p300 to activate CDC42 transcription and enhancing HNRNPA2B1 to stabilize CDC42 mRNA dependent on m6A

LINC00355 is involved in the tumorigenesis of several types of cancer. We verified that LINC00355 is upregulated in gastric cancer (GC) and contributes to GC cells' proliferation and metastasis. RNA sequencing (RNA-seq) and rescue assays suggested that LINC00355 controls gastric carcinogenesis by regulating the expression of cell division cycle 42 (CDC42) guanosine triphosphatase (GTPases), thereby activating their downstream pathways. Most previous studies have shown that LINC00355 acts as a ceRNA by sponging miRNAs to modulate downstream gene expression. Our group focus on epigenetic regulatory potential of LINC00355 in gene expression. Mechanistically, LINC00355 binds to p300 histone acetyltransferase, specifying the histone modification pattern on the CDC42 promoter to activate CDC42 transcription, thereby altering GC cell biology. In addition, HNRNPA2B1, which is upregulated by LINC00355, recognizes the N6-methyladenosine (m6A) sites of CDC42 and enhances the stability of CDC42 mRNA transcripts. Therefore, LINC00355 is mechanistically, functionally, and clinically oncogenic in GC cells.

Molecular subgroup establishment and signature creation of lncRNAs associated with acetylation in lung adenocarcinoma

BACKGROUND

The significance of long non-coding RNAs (lncRNAs) as pivotal mediators of histone acetylation and their influential role in predicting the prognosis of lung adenocarcinoma (LUAD) has been increasingly recognized. However, there remains uncertainty regarding the potential utility of acetylation-related lncRNAs (ARLs) in prognosticating the overall survival (OS) of LUAD specimens.

METHODS

The RNA-Seq and clinical information were downloaded from The Cancer Genome Atlas (TCGA). Through the differential analysis, weighted correlation network analysis (WGCNA), Pearson correlation test and univariate Cox regression, we found out the prognosis associated ARLs and divided LUAD specimens into two molecular subclasses. The ARLs were employed to construct a unique signature through the implementation of the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm. Subsequently, the predictive performance was evaluated using ROC analysis and Kaplan-Meier survival curve analysis. Finally, ARL expression in LUAD was confirmed by quantitative real-time PCR (qRT-PCR).

RESULTS

We triumphantly built a ARLs prognostic model with excellent predictive accuracy for LUAD. Univariate and multivariate Cox analysis illustrated that risk model served as an independent predictor for influencing the overall survival OS of LUAD. Furthermore, a nomogram exhibited strong prognostic validity. Additionally, variations were observed among subgroups in the field of immunity, biological functions, drug sensitivity and gene mutations within the field.

CONCLUSIONS

Nine ARLs were identified as promising indicators of personalized prognosis and drug selection for people suffering with LUAD.

The landscape of lncRNAs in gastric cancer: from molecular mechanisms to potential clinical applications

Gastric cancer (GC) is a highly prevalent and deadly malignant neoplasm worldwide. Currently, long non-coding RNAs (lncRNAs) have recently been identified as crucial regulators implicated in GC development and progression. Dysregulated expression of lncRNAs is commonly associated with enhanced tumor migration, invasiveness, and therapy resistance, highlighting their potential as promising targets for clinical applications. This review offers a comprehensive historical overview of lncRNAs in GC, describes the molecular mechanisms, and discusses the prospects and challenges of establishing lncRNAs as precision biomarkers.

A novel long non-coding RNA XLOC_004787, is associated with migration and promotes cancer cell proliferation by downregulating mir-203a-3p in gastric cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) have been identified as important regulatory factors implicated in a wide array of diseases, including various forms of cancer. However, the roles of most lncRNAs in the progression of gastric cancer (GC) remain largely unexplored. This study investigates the biological function and underlying mechanism of a novel lncRNA, XLOC_004787 in GC.

METHODS

The location of XLOC_004787 in GES-1 cells and HGC-27 cells were detected by fluorescence in situ hybridization (FISH) assay. The expression levels of XLOC_004787 were assessed using quantitative real-time fluorescence PCR (qRT-PCR) in various cell lines, including GES-1, MGC-803, MKN-45, BGC-823, SGC-7901, and HGC-27 cells. Functional assays such as Transwell migration, cell counting kit-8 (CCK-8), and colony formation experiments were employed to analyze the effects of XLOC_004787 and miR-203a-3p on cell migration and proliferation. Protein levels associated with GC in these cell lines were examined by Western blotting. The intracellular localization of β-catenin and P-Smad2/3 was assessed using immunofluorescence (IF) assay. Additionally, the interaction between XLOC_004787 and miR-203a-3p was investigated using a dual luciferase assay.

RESULTS

XLOC_004787 was localized at both the cytoplasm and nucleus of GES-1 cells and HGC-27 cells. Compared to normal tissues and GES-1 cells, XLOC_004787 expression was significantly upregulated in GC tissues and cells, with the highest and lowest expression observed in SGC-7901 and HGC-27 cells, respectively. Furthermore, a reduced expression of XLOC_004787 was seen to inhibit migration and proliferation in SGC-7901 cells. Western blotting analysis revealed that a decrease in XLOC_004787 expression correspondingly decreased the expression of N-cadherin, mmp2, mmp9, Snail, Vimentin, β-catenin, C-myc, Cyclin D1, and TGF-β, while concurrently increasing E-cadherin expression. This was also associated with diminished expression of P-Smad2/3 in relation to Smad2/3, and reduced P-Gsk3β expression in comparison to Gsk3β. Additionally, the nuclear entry of P-Smad2/3 and β-catenin was reduced by lower XLOC_004787 expression. Amplifying XLOC_004787 expression via pcDNA_XLOC_004787 suggested a potential for cancer promotion. Notably, XLOC_004787 was found to negatively regulate mir-203a-3p expression, with potential binding sites identified between the two. Higher mir-203a-3p expression was observed to decrease migration and proliferation, and enhance E-cadherin expression. Conversely, suppression of mir-203a-3p expression suggested a potential promotion of proliferation and migration in GC cells.

CONCLUSIONS

These results suggest that XLOC_004787, found to be upregulated in GC tissues, potentially promotes proliferation and migration in GC cells. This occurs through the activation of TGF-β and Wnt/β-catenin signaling pathways and the expression of EMT-related proteins. Additionally, XLOC_004787 may influence cell migration and proliferation by modulating the signaling pathway via the adsorption and inhibition of mir-203a-3p.