LncRNA LOXL1-AS1 facilitates the tumorigenesis and stemness of gastric carcinoma via regulation of miR-708-5p/USF1 pathway

A comprehensive review on lncRNA LOXL1-AS1: molecular mechanistic pathways of lncRNA LOXL1-AS1 in tumorigenicity of cancer cells

Long non-coding RNAs (lncRNAs) are versatile RNAs that regulate various cellular processes, such as gene regulation, by acting as signals, decoys, guides, and scaffolds. A novel recognized lncRNA, LOXL1-antisense RNA 1 (LOXL1-AS1), is dysregulated in some diseases, including cancer, and acts as an oncogenic lncRNA in many types of cancer cells. Upregulation of LOXL1-AS1 has been involved in proliferation, migration, metastasis, and EMT, as well as inhibiting apoptosis in cancer cells. Most importantly, the malignant promoting activity of LOXL1-AS1 can be mostly mediated by sequestering specific miRNAs and inhibiting their binding to the 3´UTR of their target mRNAs, thereby indirectly regulating gene expression. Additionally, LOXL1-AS1 can decoy transcription factors and proteins and prevent their binding to their regulatory regions, inhibiting their mechanistic activity on the regulation of gene expression and signaling pathways. This review presents the mechanistic pathways of the oncogenic role of LOXL1-AS1 by modulating its target miRNAs and proteins in various cancer cells. Having information about the molecular mechanisms regulated by LOXL1-AS1 in cancer cells can open ways to find out particular prognostic biomarkers, as well as discover novel therapeutic approaches for different types of cancer.

Involvement of long non-coding RNA LOXL1-AS1 in the tumourigenesis and development of malignant tumours: a narrative review

Background and Objective

Long noncoding RNAs (lncRNAs) are involved in a wide variety of physiological and pathological processes in organisms. LncRNAs play a significant role as oncogenic or tumour-suppressing factors in various biological processes associated with malignant tumours and are closely linked to the occurrence and development of malignancies. Lysyl oxidase like 1 antisense RNA 1 (LOXL1-AS1) is a recently discovered lncRNA. It is upregulated in various malignant tumours and is associated with pathological characteristics such as tumour size, tumour node metastasis (TNM) staging, lymph node metastasis, and tumour prognosis. LOXL1-AS1 exerts its oncogenic role by competitively binding with multiple microRNAs (miRs), thereby regulating the expression of downstream target genes and controlling relevant signalling pathways. This article aims to explore the structure and the function of LOXL1-AS1, and the relationship between LOXL1-AS1 and the occurrence and development of human malignant tumours to provide a reference for further clinical research.

Methods

English literature on LOXL1-AS1 in the occurrence and development of various malignant tumours was searched in PubMed. The main search terms were "LOXL1-AS1", "tumour".

Key Content and Findings

This article mainly summarizes the biological processes in which LOXL1-AS1 is involved in various human malignant tumours and the ways in which this lncRNA affects malignant biological behaviours such as proliferation, metastasis, invasion, and apoptosis of tumour cells through different molecular regulatory mechanisms. This article also explores the potential clinical significance and application prospects of LOXL1-AS1, aiming to provide a theoretical basis and reference for the clinical diagnosis, treatment, and screening of prognostic markers for malignant tumours.

Conclusions

LOXL1-AS1 acts as a competing endogenous RNA (ceRNA), binding to miRs to regulate downstream target genes and exert its oncogenic effects. LOXL1-AS1 may become a novel molecular biomarker for cancer diagnosis and treatment in humans, and it may also serve as an independent prognostic indicator.

Circ-0075305 hinders gastric cancer stem cells by indirectly disrupting TCF4-β-catenin complex and downregulation of SOX9

CircRNAs are covalently closed, single-stranded RNA that form continuous loops and play a crucial role in the initiation and progression of tumors. Cancer stem cells (CSCs) are indispensable for cancer development; however, the regulation of cancer stem cell-like properties in gastric cancer (GC) and its specific mechanism remain poorly understood. We elucidate the specific role of Circ-0075305 in GC stem cell properties. Circ-0075305 associated with chemotherapy resistance was identified by sequencing GC cells. Subsequent confirmation in both GC tissues and cell lines revealed that patients with high expression of Circ-0075305 had significantly better overall survival (OS) rates than those with low expression, particularly when treated with postoperative adjuvant chemotherapy for GC. In vitro and in vivo experiments confirmed that overexpression of Circ-0075305 can effectively reduce stem cell-like properties and enhance the sensitivity of GC cells to Oxaliplatin compared with the control group. Circ-0075305 promotes RPRD1A expression by acting as a sponge for corresponding miRNAs. The addition of LF3 (a β-catenin/TCF4 interaction antagonist) confirmed that RPRD1A inhibited the formation of the TCF4-β-catenin transcription complex through competitive to β-catenin and suppressed the transcriptional activity of stem cell markers such as SOX9 via the Wnt/β-catenin signaling pathway. This leads to the downregulation of stem cell-like property-related markers in GC. This study revealed the underlying mechanisms that regulate Circ-0075305 in GCSCs and suggests that its role in reducing β-catenin signaling may serve as a potential therapeutic candidate.

Long non-coding RNA LOXL1-AS1: a potential biomarker and therapeutic target in human malignant tumors

Long non-coding RNAs (lncRNAs) are transcripts that contain more than 200 nucleotides. Despite their inability to code proteins, multiple studies have identified their important role in human cancer through different mechanisms. LncRNA lysyl oxidase like 1 antisense RNA 1 (LOXL1-AS1), a newly discovered lncRNA located on human chromosome 15q24.1, has recently been shown to be involved in the occurrence and progression of various malignancies, such as colorectal cancer, gastric cancer, hepatocellular carcinoma, prostate cancer, non-small cell lung cancer, ovarian cancer, cervical cancer, breast cancer, glioma, thymic carcinoma, pancreatic carcinoma. LOXL1-AS1 acts as competitive endogenous RNA (ceRNA) and via sponging various miRNAs, including miR-374b-5p, miR-21, miR-423-5p, miR-589-5p, miR-28-5p, miR-324-3p, miR-708-5p, miR-143-3p, miR-18b-5p, miR-761, miR-525-5p, miR-541-3p, miR-let-7a-5p, miR-3128, miR-3614-5p, miR-377-3p and miR-1224-5p to promote tumor cell proliferation, invasion, migration, apoptosis, cell cycle, and epithelial-mesenchymal transformation (EMT). In addition, LOXL1-AS1 is involved in the regulation of P13K/AKT and MAPK signaling pathways. This article reviews the current understanding of the biological function and clinical significance of LOXL1-AS1 in human cancers. These findings suggest that LOXL1-AS1 may be both a reliable biomarker and a potential therapeutic target for cancers.

Potential role of lncRNA LOXL1-AS1 in human cancer development: a narrative review

Background and Objective

Long non-coding RNAs (lncRNAs) are a group of non-coding RNAs consisting of more than 200 nucleotides that are widely involved in various physiological and pathobiological processes in the body. LncRNA plays a crucial role in tumorigenesis and development with its unique functions, such as playing a role in a variety of biological processes of malignant tumors as a cancer-promoting factor or a cancer-suppressor factor. Lysyl oxidase-like protein 1-antisense RNA1 (LOXL1-AS1) is a novel functional lncRNA recently reported. This article reviews the current findings on the role of LOXL1-AS1 in cancer, and discusses the potential clinical significance and application prospects, in order to provide a theoretical basis and reference for the clinical diagnosis, treatment and screening of prognostic markers for malignant tumors.

Methods

The PubMed and Embase databases were searched using the keywords "cancer" or "tumor" or "neoplasm" and "LOXL1-AS1" for publications from 2018 to the present. The English literature was searched, with a focus on relevant articles. These articles validated the role and mechanism of LOXL1-AS1 in different cancers.

Key Content and Findings

LOXL1-AS1 is a recently reported novel lncRNA, which is abnormally expressed and upregulated in more than ten cancers, and is positively correlated with adverse clinical features and poor prognosis in cancer patients. LOXL1-AS1 competently binds to a variety of microRNAs to regulate the expression of downstream target genes and regulate related signaling pathways, including proliferation, migration, invasion and inhibition of malignant biological behaviors such as apoptosis.

Conclusions

LOXL1-AS1 is expected to become a novel biomarker for cancer diagnosis and treatment, with great potential as an independent prognostic indicator.

TEAD4 Activates PCSK9 to Promote Stomach Adenocarcinoma Cell Stemness through Fatty Acid Metabolism

INTRODUCTION

This study attempted to investigate how proprotein convertase subtilisin/kexin type 9 (PCSK9) influences the stemness of stomach adenocarcinoma (STAD) cells.

METHODS

CCK-8 and sphere-formation assays were used to detect cell viability and stemness. qRT-PCR and Western blot were used to detect PCSK9 and TEAD4 expression. The binding relationship was verified by dual-luciferase and chromatin immunoprecipitation assays. The effect of TEAD4 activating PCSK9 on the stemness of STAD cells was detected by bioinformatics, BODIPY 493/503, Oil red O, Western blot, and kits. In vivo experiments verified the role of the TEAD4/PCSK9 axis in tumor formation in nude mice.

RESULTS

PCSK9 and TEAD4 were highly expressed in STAD. PCSK9 was enriched in the fatty acid metabolism (FAM) pathway. PCSK9 activated the fatty acid metabolism and promoted the proliferation and stemness of STAD cells. TEAD4 as a transcription factor upstream of PCSK9, cell experiments revealed that knockdown of PCSK9 inhibited STAD cell stemness, whereas further addition of fatty acid inhibitors could attenuate the promoting effect on STAD cell stemness brought by STAD overexpression. Rescue experiments showed overexpressed PCSK9 exerted an inhibitory effect on the stemness of STAD cells brought by TEAD4 knockdown. The hypothesis that TEAD4/PCSK9 axis can promote STAD cell growth was confirmed by in vivo experiments.

CONCLUSION

Transcription factor TEAD4 could activate PCSK9 to promote the stemness of STAD cells through FAM. These results added weight to the assumption that TEAD4/PCSK9 axis has the potential to be the therapeutic target that inhibits cancer stem cell in STAD.

Long non-coding RNA GATA6-AS1 is mediated by N6-methyladenosine methylation and inhibits the proliferation and metastasis of gastric cancer

BACKGROUND

Through experimental research on the biological function of GATA6-AS1, it was confirmed that GATA6-AS1 can inhibit the proliferation, invasion, and migration of gastric cancer cells, suggesting that GATA6-AS1 plays a role as an anti-oncogene in the occurrence and development of gastric cancer. Further experiments confirmed that the overexpression of fat mass and obesity-associated protein (FTO) inhibited the expression of GATA6-AS1, thereby promoting the occurrence and development of gastric cancer.

AIM

To investigate the effects of GATA6-AS1 on the proliferation, invasion and migration of gastric cancer cells and its mechanism of action.

METHODS

We used bioinformatics methods to analyze the Cancer Genome Atlas (https://portal.gdc.cancer.gov/. The Cancer Genome Atlas) and download expression data for GATA6-AS1 in gastric cancer tissue and normal tissue. We also constructed a GATA6-AS1 lentivirus overexpression vector which was transfected into gastric cancer cells to investigate its effects on proliferation, migration and invasion, and thereby clarify the expression of GATA6-AS1 in gastric cancer and its biological role in the genesis and development of gastric cancer. Next, we used a database (http://starbase.sysu.edu.cn/starbase2/) to analysis GATA6-AS1 whether by m6A methylation modify regulation and predict the methyltransferases that may methylate GATA6-AS1. Furthermore, RNA immunoprecipitation experiments confirmed that GATA6-AS1 was able to bind to the m6A methylation modification enzyme. These data allowed us to clarify the ability of m6A methylase to influence the action of GATA6-AS1 and its role in the occurrence and development of gastric cancer.

RESULTS

Low expression levels of GATA6-AS1 were detected in gastric cancer. We also determined the effects of GATA6-AS1 overexpression on the biological function of gastric cancer cells. GATA6-AS1 had strong binding ability with the m6A demethylase FTO, which was expressed at high levels in gastric cancer and negatively correlated with the expression of GATA6-AS1. Following transfection with siRNA to knock down the expression of FTO, the expression levels of GATA6-AS1 were up-regulated. Finally, the proliferation, migration and invasion of gastric cancer cells were all inhibited following the knockdown of FTO expression.

CONCLUSION

During the occurrence and development of gastric cancer, the overexpression of FTO may inhibit the expression of GATA6-AS1, thus promoting the proliferation and metastasis of gastric cancer.

USF1 regulated circPRDM4 modulates tumorigenesis and immune escape in chemoresistant cervical cancer

Cervical cancer (CC) represents a major global health concern, characterized by chemoresistance and immune evasion mechanisms. Circular RNAs (circRNAs), which play a crucial role in cancer pathogenesis, particularly in the case of CC, have gained significant attention. The primary objective of this study was to investigate the functional significance of circRNAs in chemoresistant CC. A significant upregulation of circPRDM4 expression in chemoresistant CC cells. To investigate the functional consequences, we conducted circPRDM4 knockdown experiments, which resulted in the effective blockade of immune escape mechanisms employed by chemoresistant CC cells. Furthermore, circPRDM4 knockdown demonstrated a significant suppression of tumorigenesis in CC cells, highlighting its contribution to the oncogenic potential of CC. Investigating the regulatory mechanisms involved, we found that the transcriptional factor upstream stimulatory factor 1 (USF1) acts as an inducer of circPRDM4 expression. Remarkably, USF1 was found to effectively modulate CC cell immune escape via its interaction with circPRDM4. Moreover, our results revealed that USF1 is intricately involved in CC cell tumorigenesis through the regulation of circPRDM4. Collectively, our study elucidates the significant roles of circPRDM4 and its upstream regulator USF1 in chemoresistant CC cells. These findings underscore the importance of circRNAs in CC pathogenesis and provide valuable insights into the mechanisms underlying immune escape and tumorigenesis.

USF1 transcriptionally activates USP14 to drive atherosclerosis by promoting EndMT through NLRC5/Smad2/3 axis

BACKGROUND

Endothelial-to-Mesenchymal Transformation (EndMT) plays key roles in endothelial dysfunction during the pathological progression of atherosclerosis; however, its detailed mechanism remains unclear. Herein, we explored the biological function and mechanisms of upstream stimulating factor 1 (USF1) in EndMT during atherosclerosis.

METHODS

The in vivo and in vitro atherosclerotic models were established in high fat diet-fed ApoE-/- mice and ox-LDL-exposed human umbilical vein endothelial cells (HUVECs). The plaque formation, collagen and lipid deposition, and morphological changes in the aortic tissues were evaluated by hematoxylin and eosin (HE), Masson, Oil red O and Verhoeff-Van Gieson (EVG) staining, respectively. EndMT was determined by expression levels of EndMT-related proteins. Target molecule expression was detected by RT-qPCR and Western blotting. The release of pro-inflammatory cytokines was measured by ELISA. Migration of HUVECs was detected by transwell and scratch assays. Molecular mechanism was investigated by dual-luciferase reporter assay, ChIP, and Co-IP assays.

RESULTS

USF1 was up-regulated in atherosclerosis patients. USF1 knockdown inhibited EndMT by up-regulating CD31 and VE-Cadherin, while down-regulating α-SMA and vimentin, thereby repressing inflammation, and migration in ox-LDL-exposed HUVECs. In addition, USF1 transcriptionally activated ubiquitin-specific protease 14 (USP14), which promoted de-ubiquitination and up-regulation of NLR Family CARD Domain Containing 5 (NLRC5) and subsequent Smad2/3 pathway activation. The inhibitory effect of sh-USF1 or sh-USP14 on EndMT was partly reversed by USP14 or NLRC5 overexpression. Finally, USF1 knockdown delayed atherosclerosis progression via inhibiting EndMT in mice.

CONCLUSION

Our findings indicate the contribution of the USF1/USP14/NLRC5 axis to atherosclerosis development via promoting EndMT, which provide effective therapeutic targets.

USF1 modulates transcription and cellular functions by regulating multiple transcription factors in Huh7 cells

Liver cancer, including hepatocellular carcinoma (HCC), is a malignant tumor that has high rates of metastasis and mortality worldwide. Upstream transcription factor 1 (USF1) is a canonical transcription factor (TF) and is associated with the pathogenesis of several cancers, but its biological functions and molecular targets in HCC remain unclear. Huh7 cells that overexpress USF1 were used with whole transcriptome profiling through RNA sequencing and chromatin immunoprecipitation (ChIP) sequencing methods to investigate the downstream targets of USF1. Reverse transcription-quantitative PCR was then used to validate the downstream targets. The results showed that USF1 significantly regulates 350 differentially expressed genes (DEGs). The upregulated DEGs were primarily protein-coding genes enriched in immune and inflammation response pathways, while the downregulated DEGs were mainly coding long non-coding (lnc)RNAs, indicating the regulatory function of USF1. It was also demonstrated that USF1 directly binds to the promoter region of 2,492 genes, which may be involved in the viral progression and cell proliferation pathways. By integrating these two datasets, 16 overlapped genes were detected, including downregulated lncRNA-NEAT1 and upregulated TF-ETV5. The downregulated lncRNA-NEAT1 showed reverse expression pattern and prognosis result compared with that of USF1 in patients with liver cancer, while upregulated TF-ETV5 showed consistent results with USF1. Promoter region motif analysis indicated that ETV5 has more binding motifs and genes than USF1 itself for USF1-regulated DEGs, indicating that USF1 may indirectly modulate gene expression by regulating ETV5 expression in Huh7 cells. The study also validated the direct interaction between USF1 and the promoter of ETV5 using ChIP-qPCR. In summary, the results demonstrated that USF1 binds to the promoter region of thousands of genes and affects a large part of DEGs indirectly. Downstream genes, including lncRNA-NEAT1 and TF-ETV5, may also have potential functions in the regulated network by USF1 and have potential functions in the progression of HCC. The present findings suggested that USF1 and its downstream targets could be potential targets for HCC therapy in the future.

miRNA/epithelial-mesenchymal axis (EMT) axis as a key player in cancer progression and metastasis: A focus on gastric and bladder cancers

The metastasis a major hallmark of tumors that its significant is not only related to the basic research, but clinical investigations have revealed that majority of cancer deaths are due to the metastasis. The metastasis of tumor cells is significantly increased due to EMT mechanism and therefore, inhibition of EMT can reduce biological behaviors of tumor cells and improve the survival rate of patients. One of the gaps related to cancer metastasis is lack of specific focus on the EMT regulation in certain types of tumor cells. The gastric and bladder cancers are considered as two main reasons of death among patients in clinical level. Herein, the role of EMT in regulation of their progression is evaluated with a focus on the function of miRNAs. The inhibition/induction of EMT in these cancers and their ability in modulation of EMT-related factors including ZEB1/2 proteins, TGF-β, Snail and cadherin proteins are discussed. Moreover, lncRNAs and circRNAs in crosstalk of miRNA/EMT regulation in these tumors are discussed and final impact on cancer metastasis and response of tumor cells to the chemotherapy is evaluated. Moreover, the impact of miRNAs transferred by exosomes in regulation of EMT in these cancers are discussed.

LncRNA WAC-AS1 promotes osteosarcoma Metastasis and stemness by sponging miR-5047 to upregulate SOX2

Cancer stemness and osteosarcoma (OS) malignant progression are closely associated. However, the molecular mechanisms underlying this association have not been fully demonstrated. Long noncoding RNAs (lncRNAs) are an intriguing class of widely prevalent endogenous RNAs involved in OS progression, the vast majority of which have not been characterized functionally. Here, we identified tumor promoter lncRNA WAC-AS1 to be highly expressed in OS tumors and associated with worse survival. Further analysis revealed that WAC-AS1 increased tumorsphere formation of OS cells and promoted metastasis, as confirmed by cell proliferation, transwell and wound healing assays. MiR-5047 was identified as a downstream target of WAC-AS1. Subsequently, based on bioinformatics analysis, RIP assay and luciferase reporter assay, SOX2 mRNA was verified as a target of miR-5047. WAC-AS1 enhanced OS cell proliferation and stemness via acting as a ceRNA by binding to miR-5047, thereby increasing SOX2 expression. In addition, SOX2 bound to the promoter region of WAC-AS1 and promoted its transcription, thereby forming a positive feedback loop to regulate OS malignancy. Taken together, our findings show WAC-AS1 is a tumor promoter and a key regulator of OS cell stemness and metastasis via a miR-5047/SOX2 axis.

[LncRNA LINC00342 regulates gastric cancer cell proliferation, migration and invasion by targeting miR-596]

OBJECTIVE

To investigate the expression levels of LINC00342 in gastric cancer (GC) tissues and cells and the pathways mediating its effects on biological behaviors of GC cells.

METHODS

Bioinformatic analysis was performed to identify the lncRNAs and their downstream miRNAs involved in regulation of biological behaviors of GC cells. qRT-PCR was used to analyze the differential expression of LINC00342 and miR-596 in GC cell lines, human gastric mucosal cells, and GC and adjacent tissues. In human GC MGC-803 and MGC-823 cells, the effects of LINC00342 overexpression, miR-596 overexpression, LINC00342 knockdown, or miR-596 knockdown on cell proliferation, migration, invasion and cell cycle changes were examined using Edu assay, CCK-8 assay, wound healing assay, Transwell assay, and flow cytometry. The regulatory interaction between LINC00342 and miR-596 was investigated using a dual-luciferase reporter assay.

RESULTS

Informatic analysis identified LINC00342 as the candidate lncRNA regulating biological behaviors of GC cells, with miR-596 as its downstream miRNA. LINC00342 expression levels were significantly higher while miR-596 expression levels were lower in GC tissues and cell lines than in the paired adjacent tissues and human gastric mucosal cell lines (all P<0.05). In MGC-803 and MGC-823 cells, overexpression of LINC00342 significantly enhanced cell proliferation (P<0.05), migration (P<0.01), and invasion (P<0.001) and reduced the percentage of G0/G1 phase cells (P<0.01), while knocking down LINC00342 significantly suppressed cell proliferation (P<0.05), migration (P<0.01), and invasion (P<0.001) and increased G0/G1 phase cell percentage (P<0.01). Modulation of miR-596 expression levels produced the opposite effects. Dual-luciferase reporter assay confirmed the specific binding between LINC00342 and miR-596 (P=0.0067).

CONCLUSION

In GC cells, LINC00342 regulates cell proliferation, migration, and invasion by targeting miR-596.

Lysyl oxidase-like 1-antisense 1 (LOXL1-AS1) lncRNA differentially regulates gene and protein expression, signaling and morphology of human ocular cells

Pseudoexfoliation glaucoma (PEXG) is characterized by dysregulated extracellular matrix (ECM) homeostasis that disrupts conventional outflow function and increases intraocular pressure (IOP). Prolonged IOP elevation results in optic nerve head damage and vision loss. Uniquely, PEXG is a form of open angle glaucoma that has variable penetrance, is difficult to treat and does not respond well to common IOP-lowering pharmaceuticals. Therefore, understanding modulators of disease severity will aid in targeted therapies for PEXG. Genome-wide association studies have identified polymorphisms in the long non-coding RNA lysyl oxidase-like 1-antisense 1 (LOXL1-AS1) as a risk factor for PEXG. Risk alleles, oxidative stress and mechanical stretch all alter LOXL1-AS1 expression. As a long non-coding RNA, LOXL1-AS1 binds hnRNPL and regulates global gene expression. In this study, we focus on the role of LOXL1-AS1 in the ocular cells (trabecular meshwork and Schlemm's canal) that regulate IOP. We show that selective knockdown of LOXL1-AS1 leads to cell-type-specific changes in gene expression, ECM homeostasis, signaling and morphology. These results implicate LOXL1-AS1 as a modulator of cellular homeostasis, altering cell contractility and ECM turnover, both of which are well-known contributors to PEXG. These findings support LOXL1-AS1 as a key target for modifying the disease.

CCND1-associated ceRNA network reveal the critical pathway of TPRG1-AS1-hsa-miR-363-3p-MYO1B as a prognostic marker for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSC) is one of the leading causes of cancer death globally, yet there are few useful biomarkers for early identification and prognostic prediction. Previous studies have confirmed that CCND1 amplification is closely associated with head and neck oncogenesis, and the present study explored the ceRNA network associated with CCND1. Gene expression profiling of the Head and Neck Squamous Cell Carcinoma (HNSC) project of The Cancer Genome Atlas (TCGA) program identified the TPRG1-AS1-hsa-miR-363-3P-MYO1B gene regulatory axis associated with CCND1. Further analysis of the database showed that MYOB was regulated by methylation in head and neck tumors, and functional enrichment analysis showed that MYO1B was involved in "actin filament organization" and "cadherin binding ". Immune infiltration analysis suggested that MYO1B may influence tumorigenesis and prognosis by regulating the immune microenvironment of HNSC. MYO1B enhanced tumor spread through the EMT approach, according to epithelial mesenchymal transition (EMT) characterisation. We analyzed both herbal and GSCALite databases and found that CCND1 and MYO1B have the potential as predictive biomarkers for the treatment of HNSC patients. RT-qPCR validated bioinformatic predictions of gene expression in vitro cell lines. In conclusion, we found a CCND1-related ceRNA network and identified the novel TPRG1-AS1-hsa-miR-363-3p-MYO1B pathway as a possible HNSC diagnostic biomarker and therapeutic target.

Differential Expression of LOXL1-AS1 in Coronary Heart Disease and its Regulatory Mechanism in ox-LDL-Induced Human Coronary Artery Endothelial Cell Pyroptosis

OBJECTIVE

Coronary heart disease (CHD) is a notable contributor to the burden of human health. Dysregulated long non-coding RNAs (lncRNAs) are implicated in the pathogenesis of CHD. This study investigated the expression pattern of lncRNA LOXL1-AS1 in CHD and its regulatory mechanism in oxidized low-density lipoprotein (ox-LDL)-induced human coronary artery endothelial cell (HCAEC) pyroptosis.

METHODS

Serum was collected from 62 CHD patients and 62 healthy volunteers for the detection of LOXL1-AS1 expression. The value of LOXL1-AS1 in CHD diagnosis and major cardiovascular adverse event (MACE) prediction was analyzed using the ROC curve. LOXL1-AS1, miR-16-5p, and SNX16 expressions in ox-LDL-treated HCAECs were determined using RT-qPCR. NLPR3, cleaved-caspase-1, and GSDMD-N protein levels were measured using Western blot. IL-1β and IL-18 concentrations were measured using ELISA. The binding relationships between LOXL1-AS1 and miR-16-5p and miR-16-5p and SNX16 were verified. Functional rescue experiment was performed to verify the role of miR-16-5p in HCAEC pyroptosis.

RESULTS

LOXL1-AS1 was highly expressed in CHD patients. LOXL1-AS1 had diagnostic value for CHD and predictive value for MACE occurrence. ox-LDL-treated HCAECs showed reduced viability, increased IL-1β and IL-18 concentrations, and elevated NLPR3, cleaved-caspase-1, and GSDMD-N levels. LOXL1-AS1 silencing promoted cell viability and reduced pyroptosis. LOXL1-AS1 bound to miR-16-5p and miR-16-5p targeted SNX16. Inhibition of miR-16-5p reversed the inhibitory effect of LOXL1-AS1 silencing on HCAEC pyroptosis.

CONCLUSION

LOXL1-AS1 was elevated in CHD patients with a good diagnostic value for CHD and predictive value for MACE. LOXL1-AS1 downregulated miR-16-5p expression by binding to miR-16-5p to enhance ox-LDL-induced HCAEC pyroptosis, which may be associated with upregulation of SNX16 transcription.

A comprehensive review of the role of lncRNAs in gastric cancer (GC) pathogenesis, immune regulation, and their clinical applications

Gastric cancer (GC) is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide. Although numerous studies have been conducted on advanced GC, the molecular mechanisms behind it remain obscure. Long non-coding RNAs (lncRNAs) are a family of RNA transcripts capable of regulating target genes at transcriptional, post-transcriptional, and translational stages. They do this by modifying mRNAs, miRNAs, and proteins. These RNAs are critical regulators of many biological processes, including gene epigenetics, transcription, and post-transcriptional levels. This article highlights recent results on lncRNAs involved in drug resistance, proliferation, migration, angiogenesis, apoptosis, autophagy, and immune response in GC. The potential clinical implications of lncRNAs as biomarkers and therapeutic targets in GC are also discussed.

Investigations into the impact of non-coding RNA on the sensitivity of gastric cancer to radiotherapy

Non-coding RNAs (ncRNAs) are a newly discovered functional RNA different from messenger RNA, which can participate in regulating the occurrence and development of tumors. More and more research results show that ncRNAs can participate in the regulation of gastric cancer (GC) radiotherapy response, and its mechanism may be related to its effect on DNA damage repair, gastric cancer cell stemness, cell apoptosis, activation of epidermal growth factor receptor signaling pathway, etc. This article summarizes the relevant mechanisms of ncRNAs regulating the response to radiotherapy in gastric cancer, which will be directly important for the introduction of ncRNAs particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) into clinical medicine as biomarkers and therapeutic targets.

LncRNA LOXL1-AS1 expression in cancer prognosis: A meta-analysis

BACKGROUND

Several studies showed that LncRNA LOXL1 antisense RNA 1 (LOXL1-AS1) is overexpressed in a variety of cancers and plays a role as an oncogene in cancer. The present meta-analysis aims to elucidate the relationship between LOXL1-AS1 expression and prognosis and clinicopathological features among cancer patients.

METHODS

PubMed, Web of Science, Cochrane Library, and EMBASE database were comprehensively and systematically searched. Pooled odds ratios (ORs) and hazard ratios with a 95% confidence interval (CI) were employed to assess the relationship between LOXL1-AS1 expression and clinical outcomes and clinicopathological features in cancer patients.

RESULTS

The present study finally enrolled 8 studies which included 657 cancer patients. The combined results indicated that the overexpression of LOXL1-AS1 was significantly associated with shorter overall survival (pooled hazard ratio = 1.99, 95% CI 1.49-2.65, P < .00001). Meanwhile, regarding clinicopathology of cancer patients, the upregulation of LOXL1-AS1 expression was closely related to lymph node metastasis (yes vs no OR = 4.01, 95% CI: 2.02-7.96, P < .0001) and distant metastasis (yes vs no OR = 3.04, 95% CI: 1.82-5.06, P < .0001), respectively.

CONCLUSION

High expression of LOXL1-AS1 in some cancers predicts shorter overall survival, distant metastasis, and lymph node metastasis. LOXL1-AS1 shows great promise as a prognostic biomarker in cancer patients.

LncRNA LINC02535 Induces Colorectal Adenocarcinoma Progression via Modulating miR-30d-5p/CHD1

Growing evidence has suggested that lncRNAs play a significant role in the development of colorectal adenocarcinoma. LncRNA LINC02535 was a potential novel lncRNA marker of neoplastic processes of the colon. Nevertheless, the function and mechanisms of LINC02535 in colorectal adenocarcinoma remain unclear. Proteins levels were measured by western blotting. EdU, CCK-8, Transwell, and wound healing assays were performed to investigate the function of LINC02535 in colorectal adenocarcinoma. The distribution of LINC02535 in cells was evaluated by subcellular fractionation assay. The interaction among RNAs was identified by luciferase reporter and RIP assays. In this study, our findings revealed that LINC02535 was highly expressed in colorectal adenocarcinoma cells. Knockdown of LINC02535 inhibited colorectal adenocarcinoma cell proliferation, migration, and invasion. Mechanistically, LINC02535 bound with miR-30d-5p and worked as a competing endogenous RNA to facilitate the expression of messenger RNA chromodomain helicase DNA-binding protein 1 (CHD1). miR-30d-5p directly targeted the sequence of CHD1 3'-untranslated region. Notably, CHD1 upregulation abolished the suppressive influence of LINC02535 inhibition on the malignant phenotypes of colorectal adenocarcinoma cells. Overall, it was disclosed that LINC02535 played an oncogenic role in colorectal adenocarcinoma progression by sponging miR-30d-5p to upregulate CHD1 expression.

The Double Face of miR-708: A Pan-Cancer Player with Dissociative Identity Disorder

Over the last decades, accumulating evidence has shown tumor-dependent profiles of miR-708, being either up- or downregulated, and thus, acting as a "Janus" regulator of oncogenic pathways. Herein, its functional duality was assessed through a thorough review of the literature and further validation in silico using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. In the literature, miR-708 was found with an oncogenic role in eight tumor types, while a suppressor tumor role was described in seven cancers. This double profile was also found in TCGA and GEO databases, with some tumor types having a high expression of miR-708 and others with low expression compared with non-tumor counterparts. The investigation of validated targets using miRBase, miRTarBase, and miRecords platforms, identified a total of 572 genes that appeared enriched for PI3K-Akt signaling, followed by cell cycle control, p53, Apellin and Hippo signaling, endocrine resistance, focal adhesion, and cell senescence regulations, which are all recognized contributors of tumoral phenotypes. Among these targets, a set of 15 genes shared by at least two platforms was identified, most of which have important roles in cancer cells that influence either tumor suppression or progression. In a clinical scenario, miR-708 has shown to be a good diagnostic and prognosis marker. However, its multitarget nature and opposing roles in diverse human tumors, aligned with insufficient experimental data and the lack of proper delivery strategies, hamper its potential as a sequence-directed therapeutic.

miRNA Expression May Have Implications for Immunotherapy in PDGFRA Mutant GISTs

Gastrointestinal stromal tumors (GISTs) harboring mutations in the PDGFRA gene occur in only about 5-7% of patients. The most common PDGFRA mutation is exon 18 D842V, which is correlated with specific clinico-pathological features compared to the other PDGFRA mutated GISTs. Herein, we present a miRNA expression profile comparison of PDGFRA D842V mutant GISTs and PDGFRA with mutations other than D842V (non-D842V). miRNA expression profiling was carried out on 10 patients using a TLDA miRNA array. Then, miRNA expression was followed by bioinformatic analysis aimed at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted 24 differentially expressed miRNAs between D842V and non-D842V GIST patients. Pathway enrichment analysis showed that deregulated miRNAs targeted genes that are mainly involved in the immune response pathways. The miRNA-mRNA networks highlighted a signature of miRNAs/mRNA that could explain the indolent behavior of the D842V mutated GIST. The results highlighted a different miRNA fingerprint in PDGFRA D842V GISTs compared to non-D842Vmutated patients, which could explain the different biological behavior of this GIST subset.

Epithelial-mesenchymal transition-related long noncoding RNAs in gastric carcinoma

As an evolutionarily phenotypic conversion program, the epithelial-mesenchymal transition (EMT) has been implicated in tumour deterioration and has facilitated the metastatic ability of cancer cells via enhancing migration and invasion. Gastric cancer (GC) remains a frequently diagnosed non-skin malignancy globally. Most GC-associated mortality can be attributed to metastasis. Recent studies have shown that EMT-related long non-coding RNAs (lncRNAs) play a critical role in GC progression and GC cell motility. In addition, lncRNAs are associated with EMT-related transcription factors and signalling pathways. In the present review, we comprehensively described the EMT-inducing lncRNA molecular mechanisms and functional perspectives of EMT-inducing lncRNAs in GC progression. Taken together, the statements of this review provided a clinical implementation in identifying lncRNAs as potential therapeutic targets for advanced GC.

The origin of gastric cancer stem cells and their effects on gastric cancer: Novel therapeutic targets for gastric cancer

Gastric cancer (GC) is one of the most prevalent malignancies and the most common causes of cancer-related mortality worldwide. Furthermore, the prognosis of advanced GC remains poor even after surgery combined with chemoradiotherapy. As a small group of cells with unlimited differentiation and self-renewal ability in GC, accumulating evidence shows that GC stem cells (GCSCs) are closely associated with the refractory characteristics of GC, such as drug resistance, recurrence, and metastasis. With the extensive development of research on GCSCs, GCSCs seem to be promising therapeutic targets for GC. However, the relationship between GCSCs and GC is profound and intricate, and its mechanism of action is still under exploration. In this review, we elaborate on the source and key concepts of GCSCs, systematically summarize the role of GCSCs in GC and their underlying mechanisms. Finally, we review the latest information available on the treatment of GC by targeting GCSCs. Thus, this article may provide a theoretical basis for the future development of the novel targets based on GCSCs for the treatment of GC.

SEZ6L2, regulated by USF1, accelerates the growth and metastasis of breast cancer

Breast cancer (BC) is the second cause of cancer-related mortality in women. Seizure related 6 homolog like 2 (SEZ6L2), a protein presented on cell surface, is involved in tumor development. It was found to be highly expressed in BC, however, its role in BC remains unclear. Herein, we aimed to explore the role of SEZ6L2 in BC. Firstly, the correlationship between SEZ6L2 expression and the clinic pathological characteristics of patients diagnosed with BC was analyzed. Subsequently, the role of SEZ6L2 was further explored using MTT, transwell invasion, flow cytometry, colony formation and wound healing assays. The result showed that the level of SEZ6L2 was remarkably correlated with the TNM stage, HER-2 status and lymph node metastasis of BC. Knockdown of SEZ6L2 significantly suppressed the proliferation of BC cells and induced cell cycle arrest at G1 phase. In addition, SEZ6L2 knockdown repressed their migration and invasion. On the contrary, SEZ6L2 overexpression performed the opposite effects. Furthermore, SEZ6L2 also accelerated the in vivo tumorigenesis of BC cells. Additionally, according to bioinformatics resources, we identified upstream transcription factor 1 (USF1) as a transcriptional factor which bound to the promoter of SEZ6L2 and positively regulated its transcription. In conclusion, this study demonstrated that SEZ6L2 was transcriptionally regulated by USF1 and was involved in the growth and metastasis of BC cells. Revealing the role of SEZ6L2 in BC provides additional knowledge for the pathogenesis of BC, which may benefit to BC therapy.

MiR-708-5p/Pit-1 axis mediates high phosphate-induced calcification in vascular smooth muscle cells via Wnt8b/β-catenin pathway

Recently, the underlying mechanism of vascular calcification (VC) has been partially elucidated. However, it is still high incidence, and no effective treatment has been found. This study aims at figuring out the underlying mechanisms of microRNA-708-5p (miR-708-5p)/sodium-phosphate transporter 1 (Pit-1) axis in high phosphate (HP)-induced VC of T/G HA-VSMCs. Alizarin Red S staining was used to evaluate calcium salt deposition, and the activity of alkaline phosphatase (ALP) was determined by measuring the absorbance at 405 nm. RT-qPCR and Western blot were performed to assess the levels of miR-708-5p and Pit-1, the levels of ALP, Pit-1, β-catenin, glycogen synthesis kinase 3 β (GSK3β), and p-GSK3β proteins, respectively. The interaction between miR-708-5p and Pit-1 was validated by luciferase reporter assay. Our findings illustrated that miR-708-5p was downregulated and Pit-1was upregulated in HP-induced VC. MiR-708-5p mimics inhibited HP-induced VC. Further experiments demonstrated that miR-708-5p targets Pit-1. In addition, miR-708-5p inactivates the Wnt8b/β-catenin pathway via targeting Pit-1 to reduce HP-induced VC. MiR-708-5p has a crucial effect on VC via targeting Pit-1 and inhibiting Wnt8b/β-catenin pathway, it may serve as a new target for VC treatment.

Development and Validation of a Novel Stemness-Index-Related Long Noncoding RNA Signature for Breast Cancer Based on Weighted Gene Co-Expression Network Analysis

Background: Breast cancer (BC) is a major leading cause of woman deaths worldwide. Increasing evidence has revealed that stemness features are related to the prognosis and progression of tumors. Nevertheless, the roles of stemness-index-related long noncoding RNAs (lncRNAs) in BC remain unclear.

Methods: Differentially expressed stemness-index-related lncRNAs between BC and normal samples in The Cancer Genome Atlas database were screened based on weighted gene co-expression network analysis and differential analysis. Univariate Cox and least absolute shrinkage and selection operator regression analyses were performed to identify prognostic lncRNAs and construct a stemness-index-related lncRNA signature. Time-dependent receiver operating characteristic curves were plotted to evaluate the predictive capability of the stemness-index-related lncRNA signature. Moreover, correlation analysis and functional enrichment analyses were conducted to investigate the stemness-index-related lncRNA signature-related biological function. Finally, a quantitative real-time polymerase chain reaction was used to detect the expression levels of lncRNAs.

Results: A total of 73 differentially expressed stemness-index-related lncRNAs were identified. Next, FAM83H-AS1, HID1-AS1, HOXB-AS1, RP11-1070N10.3, RP11-1100L3.8, and RP11-696F12.1 were used to construct a stemness-index-related lncRNA signature, and receiver operating characteristic curves indicated that stemness-index-related lncRNA signature could predict the prognosis of BC well. Moreover, functional enrichment analysis suggested that differentially expressed genes between the high-risk group and low-risk group were mainly involved in immune-related biological processes and pathways. Furthermore, functional enrichment analysis of lncRNA-related protein-coding genes revealed that FAM83H-AS1, HID1-AS1, HOXB-AS1, RP11-1070N10.3, RP11-1100L3.8, and RP11-696F12.1 were associated with neuroactive ligand–receptor interaction, AMPK signaling pathway, PPAR signaling pathway, and cGMP-PKG signaling pathway. Finally, quantitative real-time polymerase chain reaction revealed that FAM83H-AS1, HID1-AS1, RP11-1100L3.8, and RP11-696F12.1 might be used as the potential diagnostic biomarkers of BC.

Conclusion: The stemness-index-related lncRNA signature based on FAM83H-AS1, HID1-AS1, HOXB-AS1, RP11-1070N10.3, RP11-1100L3.8, and RP11-696F12.1 could be used as an independent predictor for the survival of BC, and FAM83H-AS1, HID1-AS1, RP11-1100L3.8, and RP11-696F12.1 might be used as the diagnostic markers of BC.

An updated review of the contribution of noncoding RNAs to the progression of gastric cancer stem cells: Molecular mechanisms of viability, invasion, and chemoresistance of gastric cancer stem cells

Gastric cancer (GC) is a leading cause of death and cancer mortality in the world, with poor survival for cases with higher stages of GC. During the past decade, GC stem cells (GCSCs) - a group of cancer cells- have been the focus of numerous cancer researches. GCSCs have the capability of self-renewal and are identified to be participated in GC development, invasion, chemoresistance, and tumor relapse. Research projects have indicated the main activities of noncoding RNAs in cellular pathways. Micro (mi)RNAs and lncRNAs play important functions in the modulation of different cellular pathways in the post-transcriptional form, through their dysregulated expression in several cancers, including GC. In this paper, we highlight the impact of dysregulated expression of micro-and lncRNAs and their downstream transcripts on GCSCs. Data collection about the progression of GCSCs may be beneficial for the introduction of new insights to the GC treatment.

OUP accepted manuscript

BACKGROUND

Glioblastoma stem cells (GSCs) and their interplay with tumor-associated macrophages (TAMs) are responsible for malignant growth and tumor recurrence of glioblastoma multiforme (GBM), but the underlying mechanisms are largely unknown.

METHODS

Cell viability, stemness, migration, and invasion were measured in GSCs after the knockdown of upstream stimulating factor 1 (USF1). Luciferase assay and chromatin immunoprecipitation qPCR were performed to determine the regulation of CD90 by USF1. Immunohistochemistry and immunofluorescent staining were used to examine the expression of USF1 and GSC markers, as well as the crosstalk between GSCs and TAMs. In addition, the interaction between GSCs and TAMs was confirmed using in vivo GBM models.

RESULTS

We show that USF1 promotes malignant glioblastoma phenotypes and GSCs-TAMs physical interaction by inducing CD90 expression. USF1 predicts a poor prognosis for glioma patients and is upregulated in patient-derived GSCs and glioblastoma cell lines. USF1 overexpression increases the proliferation, invasion, and neurosphere formation of GSCs and glioblastoma cell lines, while USF1 knockdown exerts an opposite effect. Further mechanistic studies reveal that USF1 promotes GSC stemness by directly regulating CD90 expression. Importantly, CD90 of GSCs functions as an anchor for physical interaction with macrophages. Additionally, the USF1/CD90 signaling axis supports the GSCs and TAMs adhesion and immunosuppressive feature of TAMs, which in turn enhance the stemness of GSCs. Moreover, the overexpression of CD90 restores the stemness property in USF1 knockdown GSCs and its immunosuppressive microenvironment.

CONCLUSIONS

Our findings indicate that the USF1/CD90 axis might be a potential therapeutic target for the treatment of glioblastoma.

Long non-coding RNAs: Biogenesis, functions, and clinical significance in gastric cancer

Gastric cancer (GC) is one of the most prevalent malignant tumor types and the third leading cause of cancer-related death worldwide. Its morbidity and mortality are very high due to a lack of understanding about its pathogenesis and the slow development of novel therapeutic strategies. Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs with a length of more than 200 nt. They play crucial roles in a wide spectrum of physiological and pathological processes by regulating the expression of genes involved in proliferation, differentiation, apoptosis, cell cycle, invasion, metastasis, DNA damage, and carcinogenesis. The aberrant expression of lncRNAs has been found in various cancer types. A growing amount of evidence demonstrates that lncRNAs are involved in many aspects of GC pathogenesis, including its occurrence, metastasis, and recurrence, indicating their potential role as novel biomarkers in the diagnosis, prognosis, and therapeutic targets of GC. This review systematically summarizes the biogenesis, biological properties, and functions of lncRNAs and highlights their critical role and clinical significance in GC. This information may contribute to the development of better diagnostics and treatments for GC.

High expression of eIF4E is associated with tumor macrophage infiltration and leads to poor prognosis in breast cancer

Background

The expression and activation of eukaryotic translation initiation factor 4E (eIF4E) is associated with cell transformation and tumor initiation, but the functional role and the mechanism whereby it drives immune cell infiltration in breast cancer (BRCA) remain uncertain.

Methods

Oncomine, Timer and UALCAN were used to analyze the expression of eIF4E in various cancers. PrognoScan, Kaplan–Meier plotter, and GEPIA were utilized to analyze the prognostic value of eIF4E in select cancers. In vitro cell experiments were used to verify the role of eIF4E in promoting the progression of BRCA. ImmuCellAI and TIMER database were used to explore the relationship between eIF4E and tumor infiltrating immune cells. The expression of a macrophage marker (CD68⁺) and an M2-type marker (CD163⁺) was evaluated using immunohistochemistry in 50 invasive BRCA samples on tissue microarrays. The Human Protein Atlas (HPA) database was used to show the expression of eIF4E and related immune markers. LinkedOmics and NetworkAnalyst were used to build the signaling network.

Results

Through multiple dataset mining, we found that the expression of eIF4E in BRCA was higher than that in normal tissues, and patients with increased eIF4E expression had poorer survival and a higher cumulative recurrence rate in BRCA. At the cellular level, BRCA cell migration and invasion were significantly inhibited after eIF4E expression was inhibited by siRNA. Immune infiltration analysis showed that the eIF4E expression level was significantly associated with the tumor purity and immune infiltration levels of different immune cells in BRCA. The results from immunohistochemical (IHC) staining further proved that the expression of CD68⁺ and CD163⁺ were significantly increased and correlated with poor prognosis in BRCA patients (P < 0.05). Finally, interaction network and functional enrichment analysis revealed that eIF4E was mainly involved in tumor-related pathways, including the cell adhesion molecule pathway and the JAK-STAT signaling pathway.

Conclusions

Our study has demonstrated that eIF4E expression has prognostic value for BRCA patients. eIF4E may act as an essential regulator of tumor macrophage infiltration and may participate in macrophage M2 polarization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09010-0.

Study on the mechanism of LOXL1-AS1/miR-3614-5p/YY1 signal axis in the malignant phenotype regulation of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high mortality worldwide. Accumulating researches have indicated that long non‑coding RNAs (lncRNAs) are involved in varies human cancers, including HCC. Nevertheless, the specific molecular mechanism of lncRNA lysyl oxidase like 1 antisense RNA 1 (LOXL1-AS1) in HCC is still unclear.

Methods

LOXL1-AS1 expression was tested via qRT-PCR in HCC cells. Functional and mechanism assays were respectively done to evaluate the biological functions of HCC cells and the potential interaction of LOXL1-AS1 and other factors.

Results

We discovered that LOXL1-AS1 was high expressed in HCC cells. Inhibition of LOXL1-AS1 repressed cell proliferation, migration and invasion, but enhanced cell apoptosis in HCC. Further, miR-3614-5p was proven to be sponged by LOXL1-AS1. Additionally, Yin Yang 1 (YY1) was proven as the target gene of miR-3614-5p, and YY1 depletion could repress HCC cell malignant behaviors. YY1 could also transcriptionally activate LOXL1-AS1 expression. In rescue assays, we confirmed that overexpression of YY1 or miR-3614-5p inhibition could reverse the suppressive effects of LOXL1-AS1 silence on the malignant behaviors of HCC cells.

Conclusion

In short, LOXL1-AS1/miR-3614-5p/YY1 forms a positive loop in modulating HCC cell malignant behaviors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13062-021-00312-8.

Autophagy and gastrointestinal cancers: the behind the scenes role of long non-coding RNAs in initiation, progression, and treatment resistance

Gastrointestinal (GI) cancers comprise a heterogeneous group of complex disorders that affect different organs, including esophagus, stomach, gallbladder, liver, biliary tract, pancreas, small intestine, colon, rectum, and anus. Recently, an explosion in nucleic acid-based technologies has led to the discovery of long non-coding RNAs (lncRNAs) that have been found to possess unique regulatory functions. This class of RNAs is >200 nucleotides in length, and is characterized by their lack of protein coding. LncRNAs exert regulatory effects in GI cancer development by affecting different functions such as the proliferation and metastasis of cancer cells, apoptosis, glycolysis and angiogenesis. Over the past few decades, considerable evidence has revealed the important role of autophagy in both GI cancer progression and suppression. In addition, recent studies have confirmed a significant correlation between lncRNAs and the regulation of autophagy. In this review, we summarize how lncRNAs play a behind the scenes role in the pathogenesis of GI cancers through regulation of autophagy.

Exosome-mediated transfer of lncRNA HCG18 promotes M2 macrophage polarization in gastric cancer

BACKGROUND

Gastric cancer (GC) derived exosomes (Exos) aggravate GC development by facilitating M2 macrophage polarization and long non-coding RNA (lncRNA) HCG18 was highly expressed in GC. This study aimed to investigate whether the exosomal lncRNA HCG18 regulated the M2 macrophage polarization in GC and the possible mechanism.

METHODS

The isolated GC cells (GCCs)-Exos were identified using transmission electron microscopy, Nanoparticle Tracking Analysis and Western blot. The GCCs-Exos function was verified by enzyme-linked immunosorbent assay and flow cytometry. Meanwhile, the exosomal lncRNA HCG18 function was determined using thein vitro assays. Furthermore, the underlying mechanism of the exosomal lncRNA HCG18 that regulated M2 macrophage polarization in GC was investigated using dual-luciferase reporter gene assay and RNA pull-down.

RESULTS

After the validation of GCCs-Exos, the GCCs-Exos facilitated the M2 macrophage polarization. The in vitro assays confirmed that the exosomal lncRNA HCG18 positively regulated the M2 macrophage polarization. Mechanistically, lncRNA HCG18 bound to miR-875-3p, miR-875-3p bound to KLF4. Furthermore, GCCs-exosomal lncRNA HCG18 elevated the KLF4 expression by decreasing miR-875-3p in macrophages to facilitate M2 macrophage polarization, thus alleviating GC. The in vivo assays clarified that the GCCs-exosomal lncRNA HCG18 restrained the tumor growth of GC induced by M2 macrophages.

CONCLUSION

GCCs-exosomal lncRNA HCG18 elevated KLF4 expression by decreasing miR-875-3p in macrophages to facilitate the M2 macrophage polarization.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

lncRNAs as Hallmarks for Individualized Treatment of Gastric Cancer

Gastric cancer is global cancer with a high mortality rate. A growing number of studies have found the abnormal expression of lncRNA (long noncoding RNA) in many tumors, which plays a role in promoting or inhibiting cancer. Similarly, lncRNA abnormal expression plays an essential biological function in gastric cancer. This article focuses on lncRNA involvement in the development of gastric cancer in terms of cell cycle disorder, apoptosis inhibition, metabolic remodeling, promotion of tumor inflammation, immune escape, induction of angiogenesis, and epithelial mesenchymal transition (EMT). The involvement of lncRNA in the development of gastric cancer is related to drug resistance, such as cisplatin and multi-drug resistance. It can also be used as a potential marker for the diagnosis and prognosis of gastric cancer and a target for the treatment. With an in-depth understanding of the mechanism of lncRNA in gastric cancer, new ideas for personalized treatment of gastric cancer are expected.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

LOXL1‑AS1 promotes thymoma and thymic carcinoma progression by regulating miR‑525‑5p‑HSPA9

Due to the lack of specific symptoms in early thymic epithelial tumours (TETs), patients are mostly in the advanced stage at the time of presentation. The aim of the present study was to explore the mechanism by which the long noncoding RNA (lncRNA) LOXL1‑AS1 affects thymoma and thymic carcinoma progression by targeting the miR‑525‑5p‑HSPA9 axis. Bioinformatics was used to analyse the process of LOXL1‑AS1 targeting miR‑525‑5p‑HSPA9 and its expression characteristics in TET. The relationships between LOXL1‑AS1, miR‑525‑5p, HSPA9 and prognosis were analysed. The dual luciferase reporter assay was applied to verify targeting. The gene was knocked down or overexpressed by plasmid transfection. Cell counting kit 8 (CCK‑8) assay, flow cytometry and Transwell assay were used to detect cell viability, apoptosis and invasion ability, respectively. Proteins and RNAs were examined by western blot analysis and qPCR, respectively. A tumour‑burdened assay was used to perform in vivo verification. LOXL1‑AS1 and HSPA9 were overexpressed in thymoma and thymic carcinoma; high levels of LOXL1‑AS1 and HSPA9 were associated with poor prognosis, and there was a significant positive correlation between their levels. Downregulation of miR‑525‑5p expression was also associated with poor prognosis of patients. Clinical trials also demonstrated the same trends. miR‑525‑5p inhibited the expression of HSPA9 protein by targeting the 3'‑untranslated region (UTR) of HSPA9 mRNA. LOXL1‑AS1 promoted the expression of HSPA9 as a sponge targeting miR‑525‑5p. Animal experiment results also showed that knockdown of miR‑525‑5p promoted cancer by promoting the expression of HSPA9. In conclusion, LOXL1‑AS1 and HSPA9 are highly expressed in thymoma and thymic carcinoma; miR‑525‑5p is expressed at low levels in thymoma and thymic carcinoma; and downregulation of miR‑525‑5p is associated with poor prognosis. In summary, this study demonstrates that LOXL1‑AS1 acts as a sponge that targets miR‑525‑5p to promote HSPA9 expression, thereby promoting the growth and invasion and inhibiting apoptosis of thymoma and thymic carcinoma cells.

LINC00514 promotes gastric cancer cell growth and EMT progression via miR-204-3p/KRAS

Long noncoding RNAs (LncRNAs) participate in tumor development and tumorigenesis. However, the mechanism, function and expression of LINC00514 in GC remain unknown. We showed that LINC00514 was upregulated in GC specimens compared with nontumor specimens. Overexpression of LINC00514 induced cell growth and EMT progression in GC cells. By using bioinformatics prediction, we found that miR-204-3p contained binding sequences for LINC00514. Luciferase reporter analysis noted that miR-204-3p overexpression decreased the luciferase expression under LINC00514-wild-type and KRAS-wild-type reporters but not that under mutant reporter. Ectopic LINC00514 expression decreased miR-204-3p expression. miR-204-3p expression was decreased in GC specimens compared with nontumor specimens and that LINC00514 was negatively correlated with miR-204-3p in GC specimens. Furthermore, KRAS was identified as a target gene for miR-204-3p according to TargetScan. Elevated miR-204-3p expression inhibited KRAS expression in HGC-27 cells, and ectopic expression of LINC00514 enhanced KRAS expression. Elevated LINC00514 expression enhanced cell growth and EMT progression by sponging KRAS. Our data indicated that LINC00514 may act as an oncogene and therapeutic target for GC.

LINC00665 activates Wnt/β-catenin signaling pathway to facilitate tumor progression of colorectal cancer via upregulating CTNNB1

Background LINC00665 is a newly identified oncogene, which has been reported to be oncogene in various cancers. Nevertheless, its role in the progression of colorectal cancer (CRC) remains obscure to the extent. This study aimed at exploring the role and mechanism of LINC00665 in CRC progression. Materials and methods RNA and protein expression were detected via qRT-PCR and western blot. Functional assays were conducted to investigate the role of LINC00665 in the CRC cellular processes. TOP/FOP assay was performed to detect the activity of Wnt/β-catenin signaling pathway. Mechanism investigations were carried out to explore the regulatory relationship among genes. Results LINC00665 was overtly expressed in CRC cell lines at high levels. Functionally, silencing of LINC00665 could curb in vitro CRC cell growth, migration and invasion, while stimulating cell apoptosis. Mechanically, LINC00665 sponged miR-214-3p to up-regulate CTNNB1 expression, consequently activating Wnt/β-catenin signaling pathway. Furthermore, LINC00665 could bind to U2AF2 and enhance the association between U2AF2 and CTNNB1, increasing the stability of CTNNB1. CTNNB1 overexpression could reverse the suppressive effects of LINC00665 downregulation. Conclusion LINC00665 stimulates CRC progression through the activation of Wnt/β-catenin signaling pathway, which hopefully might be a therapeutic target for CRC.

LncRNA lnc_13814 promotes the cells apoptosis in granulosa cells of duck by acting as apla-miR-145-4 sponge

Follicle development is a vital factor which determines the reproductive performance of poultry. Long noncoding RNAs (lncRNAs) have been reported to maintain animal reproductive function and play key roles in ovarian development and hormone secretion. But the regulatory mechanism of lncRNAs in duck follicle development has seldom been reported. In this study, to better explore the molecular mechanism of follicle development in ducks, the follicular lncRNA was sequenced and analyzed. A total of 9,551 lncRNAs were predicted in the duck follicles. Four hundred and forty-five lncRNAs were differentially expressed between the white follicles and yellow follicles. The results of our studies showed that lnc_13814 promoted cell apoptosis in duck GCs. Furthermore, the bioinformatics analysis results demonstrated that lnc_13814 was involved in a lncRNA-miRNA-mRNA coexpression network and it was observed to sponge two follicle-related miRNAs by a luciferase activity assay. Moreover, we found that overexpression of lnc_13814 significantly increased DNA damage inducible transcript 3 (DDIT3) expression and downregulated GCs apoptosis. Finally, we found that lnc_13814 directly binds to and inhibits apla-mir-145-4; then, lnc_13814 increases the expression of DDIT3 and up-regulates GCs apoptosis. Taken together, our findings demonstrate that lncRNAs have potential effects on duck ovarian follicles and lncRNAs may represent a new approach to understand follicular development.

LncRNA LOXL1-AS1 promotes esophageal squamous cell carcinoma progression by targeting DESC1

Recently, ample evidence indicated that numerous aberrantly expressed long non-coding RNAs (lncRNAs) participated in the development of multiple malignancies. However, the expression and function of lncRNA LOXL1-AS1 in mediating esophageal squamous cell carcinoma (ESCC) carcinogenesis remains largely elusive. Here we validated that LOXL1-AS1 was significantly upregulated in ESCC tissues compared with the corresponding adjacent non-neoplastic tissues, and LOXL1-AS1 expression was positively correlated with ESCC patients' lymph node metastasis. Besides, LOXL1-AS1 knockdown impaired ESCC cells proliferation, migration and invasion capabilities in vitro. Furthermore, inhibiting LOXL1-AS1 in ESCC cells increased the percentage of cells at the G1 phase, accompanied by reducing in S phase in contrast to scramble control, and silencing of LOXL1-AS1 evoked ESCC cell apoptosis. From high throughput RNA sequencing (RNA-seq) analysis, we identified that differentially expressed in squamous cell carcinoma 1 (DESC1) was a critical downstream target of LOXL1-AS1. Taken together, we demonstrated the function and mechanism of LOXL1-AS1 in contributing ESCC progression for the first time, and indicated LOXL1-AS1 may be a novel therapeutic biomarker of ESCC.

Targeted-regulating of miR-515-5p by LncRNA LOXL1-AS1 on the proliferation and migration of trophoblast cells

OBJECTIVE

This study aims to elucidate the molecular mechanism of LOXL1-AS1 in proliferation and migration of trophoblast cells.

METHODS

We have used specific small interfering RNAs (si-RNA) and microRNA (mi-RNA) to knock down the target gene or m-RNA. In this regard we used following siRNAs: si-NC, si-LOXL1-AS1, pcDNA-NC, pcDNA-LOXL1-AS1, miR-NC, miR-515-5p. These si-RNA and miRNA were transfected into JeG-3 cells. Real-time quantitative PCR (RT-qPCR) was used to detect the expressions of LOXL1-AS1 and miR-515-5p. Western blot was used to detect Cyclin D1, matrix metalloproteinase 2 (MMP2), matrix metalloproteinases 9 (MMP9), phosphorylated p65 (p-p65), profilin of phosphorylated nuclear transcription factor κB (p-IκBα). MTT assay was used to detect cell survival rate, and the luciferase assay was used to detected the targeting relationship of LOXL1-AS1 and miR-515-5p.

RESULTS

Our results showed that human placental trophoblast cells had higher level of LOXL1-AS1 in comparison to human choriocarcinoma cells, however, human placental trophoblast cells had lower level of miR-515-5p. In addition, the expression of CyclinD1, MMP2, MMP9 were significantly decreased in JeG-3 cell lines. We observed lower cell survival rate and lower cell migration number in JeG-3 cell lines. Our results demonstrated that LOXL1-AS1 could target miR-515-5p, and subsequently reverse the inhibitory effect of LOXL1-AS1 on proliferation and migration in JEG-3 cells. Also, lower expressions of p-p65 and p-IкBα in JeG-3 cells showed that miR-515-5p could reversed the inhibitory effect of LOXL1-AS1 on NF-κB signaling pathway.

CONCLUSIONS

The low expression of LOXL1-AS1 inhibits the proliferation and migration of human choriocarcinoma cells, which might be related to miR-515-5p and NF-κB signaling pathways.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

Long non-coding RNA LINC00665 promotes melanoma cell growth and migration via regulating the miR-224-5p/VMA21 axis

Melanoma is an aggressive malignant skin tumor endangering the health of patients. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been increasingly reported to be implicated in the carcinogenesis of melanoma. Long intergenic non-coding RNA 00665 (LINC00665) has been found to exert important regulatory roles in some cancers, yet its function in melanoma remains to be investigated. QRT-PCR analysis was conducted to evaluate the relative expression of RNAs. Functional experiments in vitro including colony formation, EdU, wound-healing and transwell assays, as well as in vivo xenograft assays, were utilized to study the role of LINC00665 in melanoma. Mechanical experiments were implemented to probe into the molecular linkage of LINC00665, miR-224-5p and VMA21. LINC00665 was abnormally highly expressed in melanoma cells. Silencing LINC00665 could inhibit the proliferation and migration of melanoma cells. LINC00665 sponged miR-224-5p to upregulate VMA21. VMA21 knockdown exerted similarly interfering effects on above biological processes in melanoma cells. However, VMA21 overexpression abolished the in vitro and in vivo outcomes of LINC00665 silencing. LINC00665 promotes proliferative and migrating abilities of melanoma cells via targeting miR-224-5p/VMA21 axis.

A novel ceRNA axis involves in regulating immune infiltrates and macrophage polarization in gastric cancer

BACKGROUND

Increasing evidence suggests that the lncRNA-miRNA-mRNA regulatory network is highly correlated with gastric cancer (GC) development. However, a prognosis-associated lncRNA-miRNA-mRNA network remains to be identified in GC.

METHODS

Differentially expressed genes (DEGs) were screened by integrating 6 microarray datasets using the RRA method. Hub genes were identified by analysing their degrees in a PPI (protein-protein interaction) network. Upstream miRNAs and lncRNAs of hub genes were predicted by miRTarBase and miRNet, respectively. Key genes, miRNAs and lncRNAs were identified by evaluating their expression and prognosis in GEPIA and Kaplan-Meier plotter, respectively. A key lncRNA-miRNA-mRNA network was constructed in Cytoscape, and the correlations were analysed in the ENCORI database. We also evaluated the mRNA expression of ceRNA axes in the TIMER and Oncomine databases and their correlation with prognosis in GC patients with different clinical features using Kaplan-Meier plotter. In addition, correlations between mRNA and immune infiltrating cells in GC were investigated by the TIMER database. Finally, several experiments were conducted to verify our analyses.

RESULTS

Forty-two upregulated and 86 downregulated DEGs were obtained from the "RRA" integrated analysis. Eight of the 20 hub genes were identified as key genes by analysing their expression and prognosis. Seventeen miRNAs were predicted to target key genes, and low expression of 4 miRNAs suggested poor outcome in GC. Furthermore, 155 lncRNAs were predicted to target 4 key miRNAs, and only 5 lncRNAs were highly expressed, suggesting poor outcomes in patients with GC. Then, the H19-miR-29a-3p-COL1A2 axis was constructed by correlation analysis. In addition, COL1A2 was positively correlated with lymphatic metastasis, immune infiltrating cell levels, markers of monocytes, tumour-associated macrophages (TAMs), and M2 macrophages but not M1 macrophages in GC. The experimental results revealed that the H19-miR-29a-3p-COL1A2 axis may promote macrophage polarization from M1 to M2 in GC.

CONCLUSIONS

A novel lncRNA-miRNA-mRNA axis was identified and may be involved in regulating immune cell infiltration and macrophage polarization, which may provide new treatment strategies for GC.

Long Non-Coding RNA LOXL1-AS1 Enhances Colorectal Cancer Proliferation, Migration and Invasion Through miR-708-5p/CD44-EGFR Axis

Introduction

Colorectal cancer (CRC), the third most common cancer worldwide, involves a physiological and pathological long non-coding RNA (lncRNA) paradigm shift. It has been reported that the lncRNA LOXL1-AS1 affects tumor development for many kinds of cancers, but its functions and mechanisms in CRC remain unknown.

Methods

Expression levels of LOXL1-AS1 and miR-708-5p within CRC tissues and cell lines were measured using qRT-PCR. The performance of gain-of-function and loss-of-function assays was aimed at examining the effects of LOXL1-AS1 and miR-708-5p; colony formation and cell viability assays were carried out to measure cell multiplication; and Transwell migration and wound-healing assays were carried out for the measurement of cell migration and invasion. Luciferase reporter assay was used to verify the interactions between LOXL1-AS1 and miR-708-5p and between miR-708-5p and the CD44-EGFR signaling pathway. Finally, expression of CD44 and EGFR proteins was measured by Western blot and immunofluorescence assays.

Results

In this study, we reveal that the regulation of lncRNA LOXL1-AS1 occurs within CRC based on the correlation with poor clinical outcomes. LOXL1-AS1 knockdown along with miR-708-5p overpresentation in CRC cell lines inhibited cell multiplication, migration, and invasion. The inhibiting effect of LOXL1-AS1 knockdown on CRC was reversed by upregulating the CD44-EGFR signal pathway. From the perspective of mechanism, LOXL1-AS1 imposes sponging upon miR-708-5p and thereby promotes the CD44-EGFR signal pathway in CRC cells.

Discussion

This study demonstrated that lncRNA LOXL1-AS1 enhances multiplication, migration, invasion, and progression of CRC by sponging miR-708-5p to regulate the CD44-EGFR signal pathway.

Long noncoding RNA LINC01559 promotes pancreatic cancer progression by acting as a competing endogenous RNA of miR-1343-3p to upregulate RAF1 expression

Background: An increasing number of studies have shown that lncRNAs are involved in the biological processes of pancreatic cancer (PC). Hence, we investigated the role of a novel noncoding RNA, LINC01559, involved in PC progression.

Results: LINC01559 and RAF1 were highly expressed in PC, while miR-1343-3p had low expression. High expression of LINC01559 was significantly associated with large tumors, lymph node metastasis, and poor prognosis. Functional experiment results revealed that silencing of LINC01559 significantly suppressed PC cell proliferation and metastasis. Meanwhile, LINC01559 could act as a ceRNA to competitively sponge miR-1343-3p to up-regulate RAF1 and activate its downstream ERK pathway

Conclusions: LINC01559 functions as an oncogene in PC progression through acting as a ceRNA of miR-1343-3p. Hence, LINC01559 is a potential diagnostic and therapeutic target.

Methods: RT-qPCR was performed to determine the expression of LINC01559 and miR-1343-3p in PC. Individual patient data were collected to investigate the correlation between clinicopathological features and LINC01559 expression. Subsequently, the expression of LINC01559, miR-1343-3p, and RAF1 was altered using transfection of vectors or inhibitors. Gain- and loss-of-function assays and mechanistic assays were applied to verify the effects of LINC01559, miR-1343-3p, and RAF1 on PC cell proliferation and metastasis in vivo and in vitro.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.