Reduced expression of the long non-coding RNA AI364715 in gastric cancer and its clinical significance

The prognostic, diagnostic, and therapeutic impact of Long noncoding RNAs in gastric cancer

Gastric cancer (GC), ranking as the third deadliest cancer globally, faces challenges of late diagnosis and limited treatment efficacy. Long non-coding RNAs (lncRNAs) emerge as valuable treasured targets for cancer prognosis, diagnosis, and therapy, given their high specificity, convenient non-invasive detection in body fluids, and crucial roles in diverse physiological and pathological processes. Research indicates the significant involvement of lncRNAs in various aspects of GC pathogenesis, including initiation, metastasis, and recurrence, underscoring their potential as novel diagnostic and prognostic biomarkers, as well as therapeutic targets for GC. Despite existing challenges in the clinical application of lncRNAs in GC, the evolving landscape of lncRNA molecular biology holds promise for advancing the survival and treatment outcomes of gastric cancer patients. This review provides insights into recent studies on lncRNAs in gastric cancer, elucidating their molecular mechanisms and exploring the potential clinical applications in GC.

Long non-coding RNA signature in gastric cancer

Gastric cancer as a common human malignancy has been associated with aberrant expressions of several coding and non-coding genes. Long non-coding RNAs (lncRNAs) as regulators of gene expressions at different genomic, transcriptomic and post-transcriptomic levels are among putative biomarkers and therapeutic targets in gastric cancer. In the present study, we have searched available literature and listed lncRNAs that are involved in the pathogenesis of gastric cancer. In addition, we discuss associations between expressions of these lncRNAs and tumoral features or risk factors for gastric cancer. Based on the established role of lncRNAs in regulation of genomic stability, cell cycle, apoptosis, angiogenesis and other aspects of cell physiology, the potential of these transcripts as therapeutic targets in gastric cancer should be evaluated in future studies.

Upregulation of MANCR predicts poor survival in patients with gastric cancer

A previous study revealed that MANCR (mitotically associated long non-coding RNA) is implicated in breast cancer. The present study investigated the potential role of MANCR in gastric cancer (GC) and revealed that MANCR was upregulated in GC tissues compared with non-cancerous tissues. MANCR expression was not affected by clinical stages and a high MANCR expression level was associated with poor survival time. MicroRNA (miR)-101 was downregulated in cancer tissues compared with non-cancerous tissues and was inversely associated with MANCR expression. MANCR overexpression in GC cell lines in vitro resulted in miR-101 downregulation; however, miR-101 overexpression did not alter MANCR expression. Furthermore, MANCR overexpression promoted, while miR-101 overexpression inhibited GC cell proliferation. In addition, miR-101 overexpression decreased the effect of MANCR overexpression. The results obtained in the present study revealed that MANCR expression was associated with the survival of patients with GC, and MANCR overexpression in vitro may promote GC by downregulating miR-101 and increasing the proliferation of GC cells.

lncRNA RMRP knockdown suppress hepatocellular carcinoma biological activities via regulation miRNA-206/TACR1

Long noncoding RNA, RNA component of mitochondrial RNA processing endoribonuclease (RMRP) plays an important role in cancer development and is closely correlated with prognosis in cancer patients. However, whether RMRP affects prognosis in patients with hepatocellular carcinoma (HCC) remains unclear. The aim of the present study was to investigate the expression level of RMRP in HCC and its correlation with prognosis in patients with HCC and explain the effects and associated mechanisms by conducting an in vitro study. The high expression level of RMRP was correlated with poor prognosis in patients with HCC. Using in vitro analysis, RMRP knockdown suppressed HCC cell proliferation, invasion, and migration (P < .05). miRNA-206 overexpression had similar effects in HCC cell lines (Bel-7402 and Huh-7). Using Western blot analysis and cellular immunofluorescence detection, RMRP downregulation significantly suppressed TACR1/Erk1/2 pathway, while miRNA-206 was significantly upregulated (P < .05). RMRP downregulation inhibits HCC-related biological activities by the regulation of miRNA-206/TACR1.

Long Non-coding RNA Zinc Finger Antisense 1 (ZFAS1) Regulates Proliferation, Migration, Invasion, and Apoptosis by Targeting MiR-7-5p in Colorectal Cancer

Background

Colorectal cancer (CRC) is one of the most common tumors, the causes of which remain unclear. Recently, many kinds of long non-coding RNAs (lncRNAs) have been identified to have an important role in the biological function of CRC. However, the effect of lncRNA zinc finger antisense 1 (ZFAS1) on development of CRC is still incompletely clear.

Material/Methods

Firstly, the expression of ZFAS1 and microRNA (miR)-7-5p in 40 CRC tissues and adjacent tissues was measured by real-time polymerase chain reaction. Then, we detected the cell proliferation, migration, invasion, and apoptosis in CRC cell lines by using Cell Counting Kit-8 assay, colony formation assay, flow analysis, and Transwell assay, respectively. Then, the relationship between ZFAS1 and miR-7-5p was verified by luciferase reporter assay. Finally, rescue experiments were conducted to confirmed that interaction of ZFAS1 and miR-7-5p in vitro.

Results

Our results showed that ZFAS1 was upregulated in CRC tissues, correlated with overall survival rates, and negatively related to the expression of miR-7-5p. It was verified that miR-7-5p was a direct target of ZFAS1 by bioinformatics analysis and luciferase reporter assay. In addition, knockdown of miR-7-5p inhibited proliferation, migration, and invasion, and promoted apoptosis in CRC cell lines, which could be rescue by miR-7-5p inhibitor.

Conclusions

Our study indicated that ZFAS1 directly targeted miR-7-5p, and knockdown of it could inhibit tumor growth, migration, invasion, and induce apoptosis in CRC. These data might provide a potent treatment mechanism or promising biomarker for CRC.

LncRNAs with miRNAs in regulation of gastric, liver, and colorectal cancers: updates in recent years

Long noncoding RNA (lncRNA) is a kind of RNAi molecule composed of hundreds to thousands of nucleotides. There are several major types of functional lncRNAs which participate in some important cellular pathways. LncRNA-RNA interaction controls mRNA translation and degradation or serves as a microRNA (miRNA) sponge for silencing. LncRNA-protein interaction regulates protein activity in transcriptional activation and silencing. LncRNA guide, decoy, and scaffold regulate transcription regulators of enhancer or repressor region of the coding genes for alteration of expression. LncRNA plays a role in cellular responses including the following activities: regulation of chromatin structural modification and gene expression for epigenetic and cell function control, promotion of hematopoiesis and maturation of immunity, cell programming in stem cell and somatic cell development, modulation of pathogen infection, switching glycolysis and lipid metabolism, and initiation of autoimmune diseases. LncRNA, together with miRNA, are considered the critical elements in cancer development. It has been demonstrated that tumorigenesis could be driven by homeostatic imbalance of lncRNA/miRNA/cancer regulatory factors resulting in biochemical and physiological alterations inside the cells. Cancer-driven lncRNAs with other cellular RNAs, epigenetic modulators, or protein effectors may change gene expression level and affect the viability, immortality, and motility of the cells that facilitate cancer cell cycle rearrangement, angiogenesis, proliferation, and metastasis. Molecular medicine will be the future trend for development. LncRNA/miRNA could be one of the potential candidates in this category. Continuous studies in lncRNA functional discrepancy between cancer cells and normal cells and regional and rational genetic differences of lncRNA profiles are critical for clinical research which is beneficial for clinical practice.

LncRNA ZEB2-AS1 contributes to the tumorigenesis of gastric cancer via activating the Wnt/β-catenin pathway

Studies have shown that long noncoding RNA Zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) is involved in the progression of lung cancer, bladder cancer, and hepatocellular carcinoma. However, its role in the pathogenesis of gastric cancer remains unknown. The Wnt/β-catenin pathway contributes to the development of gastric cancer. ZEB2-AS1 expression was firstly detected in the gastric carcinoma tissue samples as well as in gastric cancer cells. Knockdown of ZEB2-AS1 was performed by ZEB2-AS1-shRNA, and the viability, migration, invasion, and apoptosis of gastric cancer cells were determined by CCK-8, scratch assay, transwell, and flow cytometry, respectively. Furthermore, levels of Ki-67, PCNA, VEGF, MMP9, epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and ZEB2), cleaved caspase 3/8/9 and PARP, active β-catenin, c-Myc, cyclinD1, and AXIN2 were assayed by Western blot or real-time PCR. Additionally, the role and mechanism of ZEB2-AS1 were confirmed in a xenograft nude mouse model. We found ZEB2-AS1 expression was increased in gastric carcinoma samples, and it was correlated with tumor progression. Also, its expression was elevated in gastric cancer cells. Knockdown of ZEB2-AS1 reduced the proliferation, migration, invasion, and EMT, but increased the apoptosis of gastric carcinoma cells. Furthermore, ZEB2-AS1 downregulation remarkably suppressed the expression of Ki-67, PCNA, VEGF and MMP9, and the activation of Wnt/β-catenin signaling, whereas elevated the levels of cleaved caspase 3/8/9 and PARP in gastric cancer cells. And ZEB2 overexpression reversed the effects of ZEB2-AS1 downregulation on the proliferation, EMT and inactivation of Wnt/β-catenin signaling. Additionally, ZEB2-AS1 knockdown inhibited tumor growth, Ki-67 staining, and the expression of VEGF, MMP9, active β-catenin, c-Myc, cyclinD1, and AXIN2 in mice. In conclusion, ZEB2-AS1 promotes the tumorigenesis of gastric carcinoma that is related to the upregulation of ZEB2 and the activation of the Wnt/β-catenin pathway.

Long noncoding RNAs in gastric cancer carcinogenesis and metastasis

Recent studies of the human transcriptome, most prominently by the ENCyclopedia Of DNA Elements project, have revealed an unexpected number of noncoding RNAs (ncRNAs). Long noncoding RNAs (lncRNAs) are typically referred to a heterogeneous group of polyadenylated long ncRNAs, with a length of > 200 nt. LncRNAs constitute an integral part of tumor biology, with many lncRNAs discovered to be aberrantly expressed in various cancer types. They are involved in many aspects of cancer pathogenesis from its initiation to progression, metastasis and treatment response. Gastric cancer (GC) is the third leading cause of cancer death worldwide. Despite the current improvements of life expectancy and survival rate, most of the patients are diagnosed when their cancer has been progressed to advanced stages. Therefore, unraveling the molecular mechanisms of GC to find early-stage biomarkers is urgent. As the list of lncRNAs with deregulated expression in GC is steadily expanding, these molecules offer a source for developing GC-specific biomarkers. In this review, we will present and discuss those lncRNAs whose expression has been shown to be deregulated in GC.

Decreased long non-coding RNA MTM contributes to gastric cancer cell migration and invasion via modulating MT1F

The role of long non-coding RNAs (lncRNA) on gastric cancer (GC) are an emerging field. Here, we focused on a cancer-related lncRNA MTM and tried to explore its correlation with the development of GC. The expression of MTM was detected by qRT-PCR in GC cell lines and tissues. The relationship between MTM level and clinicopathological factors was then analyzed. Cell biological assays with overexpression or co-transfection approaches were examined to probe the functional relevance of this lncRNA and its potential targets. The results showed that MTM expression was significantly lower in GC cell lines and tissues, and closely correlated with lymphatic metastasis, invasive depth, tumor staging and overall survival. Overexpression of MTM significantly inhibited GC cell migration and invasion, suppressed cell proliferation and induced cell apoptosis. In addition, we found a positive correlation between the expression level of MTM and MT1F both in cell and tissue samples. MT1F overexpression decreased GC cell migration and invasion, while knockdown of MT1F restored cell migration and invasion in MTM-overexpressing GC cells, suggesting MT1F as a key target of MTM. Conclusively, abnormal decreased expression of MTM was observed in human GC, which might contribute to gastric carcinogenesis by modulating MT1F expression.

Downregulated long non-coding RNA TCONS_00068220 upregulates apoptosis in gastric cancer cells

Long non-coding RNAs (lncRNAs) are emerging as a fundamental class of biological effect or molecules that perform pivotal functions in the regulation of the genome. With advances in bioinformatics and genomics, extensive identification and characterization of lncRNAs is now possible. They regulate cellular growth, differentiation and apoptosis. Dysregulation of lncRNAs has been associated with numerous types of human cancer. In the present study, the expression profile of differentially expressed genes (DEGs) and lncRNAs in gastric cancer (GC) samples and normal tissue samples was evaluated with bioinformatics. The biological functions of the predicted lncRNA TCONS_00068220 were focused on; the DEGs co-expressed with TCONS_00068220 were enriched in cancer-associated pathways. TCONS_00068220 was demonstrated to be upregulated in GC tissues and cell lines compared with normal controls. In addition, an increased rate of apoptosis was observed in NCI-N87 cells following transfection with small interfering RNA against TCONS_00068220. These data suggest that TCONS_00068220 may be associated with the pathogenesis of GC, and it may serve as a potential therapeutic target.

Exosomes-mediated transfer of long noncoding RNA ZFAS1 promotes gastric cancer progression

BACKGROUND

ZFAS1 is a newly identified long noncoding RNA (lncRNA) that promotes tumor growth and metastasis. Exosomes mediate cellular communications in cancer by transmitting active molecules. The presence of ZFAS1 in the circulating exosomes and the roles of exosomal ZFAS1 in gastric cancer (GC) remains unknown. The aim of this study was to investigate the potential roles of exosomal ZFAS1 in GC.

METHODS

The expression of ZFAS1 was examined in the tumor tissues, serum samples, serum exosomes of GC patients and cell lines using qRT-PCR. The correlation between ZFAS1 expression and the clinicopathological characteristics was analyzed. The characteristics of exosomes were identified using transmission electron microscope (TEM), Nanoparticle Tracking Analysis (NTA), and western blot. The biological roles of ZFAS1 in GC cell growth and mobility were investigated using cell counting, cell colony formation, and transwell migration assay. The potential mechanism of ZFAS1 was demonstrated using flow cytometry, western blot, and qRT-PCR.

RESULTS

ZFAS1 expression was elevated in GC cells, tumor tissues, serum and serum exosomes of GC patients. The increased ZFAS1 expression was significantly correlated with lymphatic metastasis and TNM stage. ZFAS1 knockdown inhibited the proliferation and migration of GC cells by suppressing cell cycle progression, inducing apoptosis, and inhibiting epithelial-mesenchymal transition (EMT). On the contrary, ZFAS1 overexpression promoted the proliferation and migration of GC cells. Moreover, ZFAS1 was present in exosomes and could be transmitted by exosomes to enhance GC cell proliferation and migration.

CONCLUSION

ZFAS1 could be delivered by exosomes to promote GC progression, which suggests that ZFAS1 may serve as a potential diagnostic and prognostic biomarker for GC.

Molecular mechanisms of long noncoding RNAs on gastric cancer

Long noncoding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides. Aberrant expression of lncRNAs has been found associated with gastric cancer, one of the most malignant tumors. By complementary base pairing with mRNAs or forming complexes with RNA binding proteins (RBPs), some lncRNAs including GHET1, MALAT1, and TINCR may mediate mRNA stability and splicing. Other lncRNAs, such as BC032469, GAPLINC, and HOTAIR, participate in the competing endogenous RNA (ceRNA) network. Under certain circumstances, ANRIL, GACAT3, H19, MEG3, and TUSC7 exhibit their biological roles by associating with microRNAs (miRNAs). By recruiting histone-modifying complexes, ANRIL, FENDRR, H19, HOTAIR, MALAT1, and PVT1 may inhibit the transcription of target genes in cis or trans. Through these mechanisms, lncRNAs form RNA-dsDNA triplex. CCAT1, GAPLINC, GAS5, H19, MEG3, and TUSC7 play oncogenic or tumor suppressor roles by correlated with tumor suppressor P53 or onco-protein c-Myc, respectively. In conclusion, interaction with DNA, RNA and proteins is involved in lncRNAs' participation in gastric tumorigenesis and development.

Roles of long noncoding RNAs in gastric cancer and their clinical applications

PURPOSE

Gastric cancer ranks as the most common cancer in the world. However, the progresses of its diagnosis and treatment are still not satisfactory. The purpose of this study is to summarize the roles of lncRNAs associated with gastric cancer.

METHODS

We searched lncRNAs associated with gastric cancer in PubMed.

RESULTS

Long noncoding RNAs (lncRNAs), transcripts larger than 200 nucleotides, regulate gene expression at various levels. They are playing important roles in the occurrence and development of gastric cancer. They are involved in signaling pathways, crosstalk with microRNAs, and affecting metastasis by regulating epithelial-to-mesenchymal transition. By acting as oncogenes or tumor suppressors, lncRNAs contribute to gastric cancer occurrence and development. Several lncRNAs including HOTAIR, HULC, LINC00152, MALAT2, H19, GHET1, and GACAT3 have been demonstrated having oncogene activities, while other lncRNAs including LEIGC, GAS5, and FER1L4 have been thought as tumor suppressors.

CONCLUSIONS

Several lncRNAs from tissue, blood, and gastric juice have shown potential values in gastric cancer diagnosis or prognosis evaluation.

Up-Regulation of Long Non-Coding RNA AB073614 Predicts a Poor Prognosis in Patients with Glioma

Dysregulated long noncoding RNAs (lncRNAs) have been found in human diseases, especially in cancer. Emerging evidence indicates that dysregulated lncRNAs are implicated in tumorigenesis and cancer progression. LncRNA AB073614 characterized as a new candidate lncRNA promotes the development of ovarian cancer. However, the role of lncRNA AB073614 in human gliomas remains unknown. The expression of AB073614 was detected in 65 glioma tissues and 13 normal brain tissues by qRT-PCR, showing that lncRNA AB073614 expression was significantly up-regulated in cancerous tissues compared with normal brain tissues (p < 0.001), and it was positively correlated with tumor grade (I-II grades vs. III-IV grades, p = 0.013) in glioma patients. Kaplan-Meier analysis demonstrated that increased AB073614 expression contributed to poor overall survival (HR (hazard ratio) = 1.952, 95%CI: 1.202-3.940, p = 0.0129). Further, univariate Cox regression analysis indicated that lncRNA AB073614 overexpression was an unfavorable prognostic factor in gliomas (HR = 1.997, 95%CI: 1.135-3.514, p = 0.016), regardless of the tumor grade (I-II grades vs. III-IV grades, HR = 1.902, 95%CI: 1.066-3.391, p = 0.029). Finally, after adjustment with age, sex, tumor grade and tumor location, multivariate Cox regression analysis suggested that both highly expressed lncRNA AB073614 (HR = 2.606, 95%CI: 1.408-4.824, p = 0.002) and high tumor grade (III-IV grades, HR = 2.720, 95%CI: 1.401-5.282, p = 0.003) could be considered independent poor prognostic indicators for glioma patients. In conclusion, our study suggested that increased lncRNA AB073614 expression may be identified as a poor prognostic biomarker in gliomas.

Long noncoding RNAs in gastric cancer: functions and clinical applications

Over the last two decades, genome-wide studies have revealed that only a small fraction of the human genome encodes proteins; long noncoding RNAs (lncRNAs) account for 98% of the total genome. These RNA molecules, which are >200 nt in length, play important roles in diverse biological processes, including the immune response, stem cell pluripotency, cell proliferation, apoptosis, differentiation, invasion, and metastasis by regulating gene expression at the epigenetic, transcriptional, and posttranscriptional levels. However, the detailed molecular mechanisms underlying lncRNA function are only partially understood. Recent studies showed that many lncRNAs are aberrantly expressed in gastric cancer (GC) tissues, gastric juice, plasma, and cells, and these alterations are linked to the occurrence, progression, and outcome of GC. Here, we review the current knowledge of the biological functions and clinical aspects of lncRNAs in GC.

Long noncoding RNAs as potential biomarkers in gastric cancer: Opportunities and challenges

Gastric cancer (GC) is a major threat to human health, and its prognosis is poor due to the lack of appropriate biomarkers. LncRNAs are a group of non-protein-coding RNAs that regulate gene expression at the transcriptional or posttranscriptional level. LncRNAs play essential roles in GC initiation and development in the same way as oncogenes or tumour suppressor genes. Recent investigations have revealed that lncRNAs are often aberrantly expressed in GC; are involved in cell proliferation, apoptosis, migration and invasion; and correlate with the malignant phenotype of GC. LncRNAs, especially the lncRNAs present in the blood and gastric juice, show potential value as biomarkers for the diagnosis of GC or for determining disease prognosis. However, there are still many challenges to be faced before lncRNAs can be used in clinical applications. In this review, we summarise lncRNAs as the potential biomarkers for GC and the current challenges associated with the clinical application.