Long non-coding RNA DDX11-AS1 facilitates gastric cancer progression by regulating miR-873-5p/SPC18 axis

ATPR induces acute promyelocytic leukemia cells differentiation and cycle arrest via the lncRNA CONCR/DDX11/PML-RARα signaling axis

Acute promyelocytic leukemia (APL) is a type of acute myeloid leukemia (AML) with a high mortality rate, and the production of PML-RARα fusion protein is the cause of its pathogenesis. Our group has synthesized a novel compound, 4-amino-2-trifluoromethyl-phenyl retinate (ATPR), by structural modification of All-trans retinoic acid (ATRA), which has strong cell differentiation-inducing effects and inhibits the expression of PML-RARα. In this study, acute promyelocytic leukemia NB4 cells before and after ATPR induction were analyzed by whole transcriptome microarray, and the expression of lncRNA CONCR was found to be significantly downregulated. The role of CONCR in ATPR-induced cell differentiation and cycle arrest was explored through overexpression and silencing of CONCR. And then the database was used to predict that CONCR may bind to DEAD/H-Box Helicase 11 (DDX11) protein to further explore the role of CONCR binding to DDX11. The results showed that ATPR could reduce the expression of CONCR, and overexpression of CONCR could reverse the ATPR-induced cell differentiation and cycle blocking effect, and conversely silencing of CONCR could promote this effect. RNA immunoprecipitation (RIP) experiments showed that CONCR could bind to DDX11, the protein expression levels of DDX11 and PML-RARα were elevated after overexpression of CONCR. These results suggest that ATPR can regulate the expression of DDX11 through CONCR to affect the expression of PML-RARα fusion protein, which in turn induces the differentiation and maturation of APL cells.

Long Noncoding RNA ACTA2-AS1 Inhibits Cell Growth and Facilitates Apoptosis in Gastric Cancer by Binding with miR-6720-5p to Regulate ESRRB

Gastric cancer (GC) is a common malignant tumor, posing a great threat to human's health and life. Previous studies have suggested aberrant expression of long non-coding RNAs (lncRNAs) in GC. This study elucidated the effects of lncRNA ACTA2-AS1 on the biological characteristics of GC. Gene expression in stomach adenocarcinoma (STAD) samples compared with normal tissues and the correlation between gene expression and prognosis of STAD patients were analyzed using bioinformatic tools. Gene expression at protein and mRNA levels in GC and normal cells was tested by western blotting and RT-qPCR. The subcellular localization of ACTA2-AS1 in AGS and HGC27 cells was identified by nuclear-cytoplasmic fractionation and FISH assay. EdU, CCK-8, flow cytometry analysis, TUNEL staining assays were conducted to evaluate the role of ACTA2-AS1 and ESRRB on GC cellular behaviors. The binding relationship among ACTA2-AS1, miR-6720-5p and ESRRB was verified by RNA pulldown, luciferase reporter assay and RIP assay. LncRNA ACTA2-AS1 was underexpressed in GC tissues and cell lines. ACTA2-AS1 elevation suppressed GC cell proliferation and induced apoptosis. Mechanistically, ACTA2-AS1 directly bound to miR-6720-5p and subsequently promoted the expression of target gene ESRRB in GC cells. Furthermore, ESRRB knockdown reversed the influence of ACTA2-AS1 overexpression on GC proliferation and apoptosis. ACTA2-AS1 plays an antioncogenic role in GC via binding with miR-6720-5p to regulate ESRRB expression.

ERVK13-1/miR-873-5p/GNMT Axis Promotes Metastatic Potential in Human Bladder Cancer though Sarcosine Production

N-methyl-glycine (sarcosine) is known to promote metastatic potential in some cancers; however, its effects on bladder cancer are unclear. T24 cells derived from invasive cancer highly expressed GNMT, and S-adenosyl methionine (SAM) treatment increased sarcosine production, promoting proliferation, invasion, anti-apoptotic survival, sphere formation, and drug resistance. In contrast, RT4 cells derived from non-invasive cancers expressed low GNMT, and SAM treatment did not produce sarcosine and did not promote malignant phenotypes. In T24 cells, the expression of miR-873-5p, which suppresses GNMT expression, was suppressed, and the expression of ERVK13-1, which sponges miR-873-5p, was increased. The growth of subcutaneous tumors, lung metastasis, and intratumoral GNMT expression in SAM-treated nude mice was suppressed in T24 cells with ERVK13-1 knockdown but promoted in RT4 cells treated with miR-873-5p inhibitor. An increase in mouse urinary sarcosine levels was observed to correlate with tumor weight. Immunostaining of 86 human bladder cancer cases showed that GNMT expression was higher in cases with muscle invasion and metastasis. Additionally, urinary sarcosine concentrations increased in cases of muscle invasion. Notably, urinary sarcosine concentration may serve as a marker for muscle invasion in bladder cancer; however, further investigation is necessitated.

DDX11-AS1 modulates DNA damage repair to enhance paclitaxel resistance of lung adenocarcinoma cells

Aim: To investigate the influence of DDX11-AS1 on paclitaxel (PTX) resistance in lung adenocarcinoma (LUAD). Methods: LncRNA expression and functional enrichment analyses were processed via bioinformatics methods. DDX11-AS1 expression was detected via quantitative real-time PCR. Cell counting kit-8, colony formation, flow cytometry and comet assays were manipulated to measure cell proliferation, apoptosis, cell cycle and DNA damage repair, respectively. Western blot was used to assess DNA damage-related protein expression. Results: DDX11-AS1 was in a high expression status in LUAD, and could promote LUAD cell proliferation and PTX resistance, while suppressing cell apoptosis. DNA damage repairing ability was also modulated by the change of DDX11-AS1 expression. Conclusion: LncRNA DDX11-AS1 promotes DNA damage repair to enhance PTX resistance in LUAD.

Biomarkers of gastric cancer: current advancement

Gastric cancer (GC) is one of the most prevalent malignant types worldwide, especially in East Asia. Due to its frequently advanced stage at diagnosis, the mortality from GC is high and the prognosis is still unsatisfactory. Thus, early detection using effective screening approaches is vital to decrease the morbidity and mortality of GC. Interestingly, biomarkers can be used for diagnosis, prediction of sensitivity to treatment, and prognosis in GC. The potential biomarkers detectable in liquid biopsies such as circulating tumor cells (CTCs), long non-coding RNAs (lncRNAs), cell-free DNA (cfDNA), microRNAs, and exosomes reveal numerous information regarding the early prediction and the outcomes for GC patients. Additionally, using the novel serum biomarkers has opened up new opportunities for diagnosing and monitoring patients with GC. This review mainly summarizes the novel progress and approaches in GC biomarkers, which could be potentially used for early diagnosis and therapy monitoring. Meanwhile, we also discussed the advantages, disadvantages, and future perspectives of GC biomarkers.

The Clinical Value of Long Noncoding RNA DDX11-AS1 as a Biomarker for the Diagnosis and Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a high-mortality malignant tumor with genetic and phenotypic heterogeneity, making predicting clinical outcomes challenging. The purpose of this investigation was to examine the potential usefulness of lncRNA DDX11 antisense RNA 1 (DDX11-AS1) as a biomarker for diagnosis and prognosis in hepatocellular carcinoma (HCC). The TCGA-LIHC datasets were searched for patients’ clinical information and RNA-seq data, which were then collected. Relative expression levels of DDX11-AS1 in HCC tissues were determined by qRT-PCR. In order to test the sensitivity and specificity of the DDX11-AS1 receiver, receiver operating characteristic curves were utilized. The association of DDX11-AS1 expression with clinicopathological factors or prognosis was statistically analyzed. We found that the levels of DDX11-AS1 were higher in HCC specimens than in normal specimens. ROC analysis showed that DDX11-AS1 was a useful marker for discriminating HCC tissues from normal nontumor specimens. According to the results of clinical tests, a high level of DDX11-AS1 expressions was significantly related to the pathologic stage ( $p=0.015$ ) and the histologic grade ( $p<0.001$ ). Survival studies indicated that patients with higher DDX11-AS1 expression had a significantly poorer overall survival ( $p=0.005$ ) and progression-free interval ( $p=0.003$ ) than those with lower DDX11-AS1 expression. Multivariate survival analysis verified that DDX11-AS1 expression level was an independent predictor for HCC patients. Overall, DDX11-AS1 may serve as a tumor promotor during HCC progression, and its high level may be a potential marker for HCC patients.

Long noncoding RNAs (lncRNAs) in pancreatic cancer progression

Long noncoding RNAs (lncRNAs) are RNA molecules involved in gene regulation at transcriptional, post-transcriptional, and epigenetic levels. LncRNAs participate in regulating apoptosis and autophagy in pancreatic cancer (PCa) and can promote and/or decrease the proliferation rate of tumor cells. The metastasis of PCa cells is tightly regulated by lncRNAs and they can affect the mechanism of epithelial-mesenchymal transition (EMT) to modulate metastasis. The drug resistance of PCa cells, especially to gemcitabine, can be affected by lncRNAs. In addition, lncRNAs enriched in exosomes can be transferred among tumor cells to regulate their proliferation and metastasis. Antitumor compounds, such as curcumin and ginsenosides, can regulate lncRNA expression in PCa therapy. As we discuss here, the expression level of lncRNAs can be considered as both a diagnostic and prognostic tool in patients with PCa.

Long non-coding RNA DDX11-AS1 promotes the proliferation and migration of glioma cells by combining with HNRNPC

Glioma is a malignant tumor of the central nervous system with complex pathogenesis, difficult operation, and a high postoperative recurrence rate. At present, there is still a lack of effective treatment. Long non-coding RNA DDX11 antisense RNA 1 (DDX11-AS1) has been shown to promote tumor development, such as hepatocellular carcinoma, esophageal cancer, etc. However, its molecular mechanism in glioma is poorly understood. In this study, we found that the expression of DDX11-AS1 was elevated in glioma tissues, and patients with high expression of DDX11-AS1 had poor prognosis. DDX11-AS1 was a potential prognostic marker. Functionally, DDX11-AS1 promoted glioma cell proliferation and migration. Mechanistically, DDX11-AS1 interacted with RNA-binding protein heterogeneous nuclear ribonucleoprotein C (HNRNPC) to promote Wnt/β-catenin and AKT pathways and the epithelial-mesenchymal transition process. In summary, our study manifests that the DDX11-AS1/HNRNPC axis may play a vital part in the occurrence and development of glioma, which provides new ideas and therapeutic targets for the diagnosis, treatment, and prognosis of glioma.

Hsa_circ_0058129 regulates papillary thyroid cancer development via miR‐873‐5p/follistatin‐like 1 axis

Background

Papillary thyroid cancer (PTC) is an endocrine malignancy with a high incidence. Circular RNAs (circRNAs) participate in regulating PTC. Here, we analyzed the role of hsa_circ_0058129 (circ_0058129) in PTC.

Methods

The expression of circ_0058129, fibronectin 1 (FN1) mRNA, microRNA‐873‐5p (miR‐873‐5p), and follistatin‐like 1 (FSTL1) was detected by qRT‐PCR and western blot. Cell proliferation was analyzed by CCK‐8, EdU, and flow cytometry analysis assays. Cell migration and invasion were evaluated by Transwell assay. The targeting relationship of miR‐873‐5p and circ_0058129 or FSTL1 was identified through dual‐luciferase reporter assay, RIP assay, and RNA pull‐down assay. Xenograft mouse model assay was implemented to determine the effect of circ_0058129 on tumor formation in vivo.

Results

The circ_0058129 and FSTL1 abundances were increased, while the miR‐873‐5p content was decreased in PTC tissues and cells compared with control groups. Circ_0058129 shortage inhibited PTC cell proliferation, migration, and invasion. Moreover, miR‐873‐5p repressed PTC cell malignancy by binding to FSTL1. Circ_0058129 targeted miR‐873‐5p to regulate FSTL1.

Conclusion

Circ_0058129 expedited PTC progression through the miR‐873‐5p/FSTL1 pathway.

MetaLnc9-Antisense RNA Contributes to Lung Cancer Metastasis via Modulating RNA-RNA Duplex with MetaLnc9

Lung cancer is a common life-threatening tumor with high malignancy and high invasiveness. Long non-coding RNAs (lncRNAs) are involved in almost every stage of tumor initiation and progression. Here, we identified an antisense lncRNA, MetaLnc9 antisense (Metalnc9-AS), which arises from the antisense strand of Metalnc9, located on chr9q34.11, while its biological function and mechanism are not clear in lung cancer. In this study, we demonstrated that the expression of Metalnc9-AS was upregulated in non-small cell lung cancer (NSCLC) tissues compared with corresponding non-tumorous tissues. The gain of MetaLnc9-AS was highly associated with the malignant features of NSCLC. Overexpression of MetaLnc9-AS enhanced tumor metastasis in vitro and in vivo. Mechanically, MetaLnc9-AS could form an RNA-RNA hybrid with its cognate sense counterpart, MetaLnc9, to regulate its expression in NSCLC cells, and that such complexes were protected from ribonuclease degradation. Thus, Metalnc9-AS might be a potential and effective treatment for NSCLC.

Exosomal and intracellular miR-320b promotes lymphatic metastasis in esophageal squamous cell carcinoma

Cancer-cell-released exosomal microRNAs (miRNAs) are important mediators of cell-cell communication in the tumor microenvironment. In this study, we sequenced serum exosome miRNAs from esophageal squamous cell carcinoma (ESCC) patients and identified high expression of miR-320b to be closely associated with peritumoral lymphangiogenesis and lymph node (LN) metastasis. Functionally, miR-320b could be enriched and transferred by ESCC-released exosomes directly to human lymphatic endothelial cells (HLECs), promoting tube formation and migration in vitro and facilitating lymphangiogenesis and LN metastasis in vivo as assessed by gain- and loss-of-function experiments. Furthermore, we found programmed cell death 4 (PDCD4) as a direct target of miR-320b through bioinformatic prediction and luciferase reporter assay. Re-expression of PDCD4 could rescue the effects induced by exosomal miR-320b. Notably, the miR-320b-PDCD4 axis activates the AKT pathway in HLECs independent of vascular endothelial growth factor-C (VEGF-C). Moreover, overexpression of miR-320b promotes the proliferation, migration, invasion, and epithelial-mesenchymal transition progression of ESCC cells. Finally, we demonstrate that METTL3 could interact with DGCR8 protein and positively modulate pri-miR-320b maturation process in an N6-methyladenosine (m6A)-dependent manner. Therefore, our findings uncover a VEGF-C-independent mechanism of exosomal and intracellular miR-320b-mediated LN metastasis and identify miR-320b as a novel predictive marker and therapeutic target for LN metastasis in ESCC.

LncRNA DDX11 antisense RNA 1 promotes EMT process of esophageal squamous cell carcinoma by sponging miR-30d-5p to regulate SNAI1/ZEB2 expression and Wnt/β-catenin pathway

LncRNA DDX11 antisense RNA 1 (DDX11-AS1) is recognized as having an imperative oncogenic role in different types of human cancer. Nevertheless, the functions, as well as the basic mechanisms of DDX11-AS1 in the EMT process of esophageal squamous cell carcinoma (ESCC), are yet to be clarified. In this research, high DDX11-AS1 expression was detected in ESCC cells as well as tissues and was linked to the poor prognosis of patients with ESCC. DDX11-AS1 promoted cell proliferation, migration, invasion ability and epithelial mesenchymal transition (EMT) process in vitro. Mechanistic analysis depicted that DDX11-AS1 may function as a ceRNA through sponging miR-30d-5p to upregulate the expression of SNAI1 and ZEB2. Meanwhile, overexpression of DDX11-AS1 might cause the activation of the Wnt/β-catenin signaling pathway via targeting miR-30d-5p. On the whole, the findings of this research illustrate that DDX11-AS1 may act as an EMT-related lncRNA to advance ESCC progression through sponging miR-30d-5p to regulate SNAI1/ZEB2 expression and activate the Wnt/β-catenin pathway, which indicates that it might serve as a probable therapeutic target for ESCC.

Close interactions between lncRNAs, lipid metabolism and ferroptosis in cancer

Abnormal lipid metabolism including synthesis, uptake, modification, degradation and transport has been considered a hallmark of malignant tumors and contributes to the supply of substances and energy for rapid cell growth. Meanwhile, abnormal lipid metabolism is also associated with lipid peroxidation, which plays an important role in a newly discovered type of regulated cell death termed ferroptosis. Long noncoding RNAs (lncRNAs) have been proven to be associated with the occurrence and progression of cancer. Growing evidence indicates that lncRNAs are key regulators of abnormal lipid metabolism and ferroptosis in cancer. In this review, we mainly summarized the mechanism by which lncRNAs regulate aberrant lipid metabolism in cancer, illustrated that lipid metabolism can also influence the expression of lncRNAs, and discussed the mechanism by which lncRNAs affect ferroptosis. A comprehensive understanding of the interactions between lncRNAs, lipid metabolism and ferroptosis could help us to develop novel strategies for precise cancer treatment in the future.

MiR-873-5p: A Potential Molecular Marker for Cancer Diagnosis and Prognosis

miR-873 is a microRNA located on chromosome 9p21.1. miR-873-5p and miR-873-3p are the two main members of the miR-873 family. Most studies focus on miR-873-5p, and there are a few studies on miR-873-3p. The expression level of miR-873-5p was down-regulated in 14 cancers and up-regulated in 4 cancers. miR-873-5p has many targeted genes, which have unique molecular functions such as catalytic activity, transcription regulation, and binding. miR-873-5p affects cancer development through the PIK3/AKT/mTOR, Wnt/β-Catenin, NF-κβ, and MEK/ERK signaling pathways. In addition, the target genes of miR-873-5p are closely related to the proliferation, apoptosis, migration, invasion, cell cycle, cell stemness, and glycolysis of cancer cells. The target genes of miR-873-5p are also related to the efficacy of several anti-cancer drugs. Currently, in cancer, the expression of miR-873-5p is regulated by a variety of epigenetic factors. This review summarizes the role and mechanism of miR-873-5p in human tumors shows the potential value of miR-873-5p as a molecular marker for cancer diagnosis and prognosis.

CircC6orf132 Facilitates Proliferation, Migration, Invasion, and Glycolysis of Gastric Cancer Cells Under Hypoxia by Acting on the miR-873-5p/PRKAA1 Axis

Background: Hypoxia is a crucial factor in the progression of various tumors, including gastric cancer (GC). Circular RNAs (circRNAs) are important regulators in GC, and this study focused on researching circC6orf132 in GC progression under hypoxia.

Methods:In vitro experiments were performed in GC cells under hypoxia (1% O₂). CircC6orf132, microRNA-873-5p (miR-873-5p), and protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) levels were examined by real-time polymerase chain reaction (qRT-PCR). Colony formation assay and transwell assay were used for detecting cell proliferation and migration or invasion. Glycolytic metabolism was evaluated using lactate production, glucose uptake, and adenosine triphosphate (ATP) level and extracellular acidification rate (ECAR). Western blotting was performed for determining protein expression. The target interaction was analyzed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. In vivo assay was conducted via mouse xenograft model.

Results: The expression of circC6orf132 was significantly high in GC cells under hypoxia. Hypoxia-induced GC proliferation, migration, invasion, and glycolysis were reversed by silencing circC6orf132. CircC6orf132 targeted miR-873-5p; and the inhibition of circC6orf132 knockdown for the effects of hypoxia on GC cells was abrogated by miR-873-5p inhibitor. PRKAA1 was validated as a downstream gene of miR-873-5p, and miR-873-5p functioned as an anticancer molecule in GC cells under hypoxia by downregulating PRKAA1 level. CircC6orf132 could regulate PRKAA1 by sponging miR-873-5p. CircC6orf132/miR-873-5p/PRKAA1 axis could regulate GC progression under the hypoxic condition. CircC6orf132 downregulation reduced tumorigenesis in vivo through affecting the miR-873-5p/PRKAA1 axis.

Conclusion: CircC6orf132 has been affirmed to promote proliferation, migration, invasion, and glycolysis in GC under hypoxia, partly by depending on the regulation of miR-873-5p/PRKAA1 axis.

Landscape analysis of lncRNAs shows that DDX11-AS1 promotes cell-cycle progression in liver cancer through the PARP1/p53 axis

Although long non-coding RNAs (lncRNAs) play important roles in tumorigenesis, the underlying mechanisms are unclear. Transcriptomic analysis of 33 hepatocellular carcinoma (HCC) samples revealed that the most enriched pathway for differentially expressed genes was related to the cell cycle process, where DDX11-AS1 is the most significant lncRNA. Upregulation of DDX11-AS1 expression through demethylation was significantly associated with a poor prognosis. Further mechanistic studies revealed that DDX11-AS1 promoted the growth of HCC by interacting with PARP1 through attenuating its binding to p53, leading to downregulated expression of p53 for inhibiting the transcription of downstream genes such as p21. Knockdown of DDX11-AS1 expression in xenograft mice using anti-DDX11-AS1 oligonucleotide suppressed liver tumor proliferation. These findings indicate that DDX11-AS1 plays a role in the development of liver cancer by affecting the cell cycle.

Long non-coding RNA DDX11-AS1 promotes esophageal carcinoma cell proliferation and migration through regulating the miR-514b-3p/RBX1 axis

Esophageal carcinoma (ESCA) is one of the most aggressive malignancies with extremely high morbidity and mortality. At present, limited advancement in ESCA treatment has achieved. Therefore, it is urgent to explore the pathogenesis and progression mechanism of ESCA to provide the basis for the formulation of novel therapeutic strategies. Previous studies have found that long non-coding RNA (lncRNA) DDX11-AS1 expression enhances the paclitaxel resistance of ESCA cells. However, the mechanisms underlying the drug resistance conferred by lncRNA DDX11-AS1 in ESCA remains to be elucidated. Our research aims to clarify the role and mechanism of lncRNA DDX11-AS1 in regulating the progression of ESCA. We found that the expression of lncRNA DDX11-AS1 in ESCA tissues and cell lines was significantly upregulated. Subsequently, silencing lncRNA DDX11-AS1 significantly inhibited the proliferation, migration and invasion of ESCA cells, and induced the level of cell apoptosis. In terms of mechanism, our data showed that miR-514b-3p/RING box protein 1 (RBX1) axis played a crucial role in the oncogenic function of lncRNA DDX11-AS1. LncRNA DDX11-AS1 expression impaired the inhibitory function of miR-514b-3p on RBX1 through sponging effect. Taken together, our data support the notion that lncRNA DDX11-AS1 promotes the progression of ESCA through miR-514b-3p/RBX1 axis. Our research uncovers the novel regulatory role of lncRNA DDX11-AS1 in ESCA and lays a theoretical basis for developing novel treatment strategy of ESCA.

Long Non-coding RNA ASNR Targeting miR-519e-5p Promotes Gastric Cancer Development by Regulating FGFR2

Gastric cancer (GC), as a common gastrointestinal tumor, is an important cause of death from cancer all around the world. Long non-coding RNAs (lncRNAs), a novel class of transcripts, have attracted great attention of researchers. However, the mechanisms of the clinical significance of most lncRNAs in human cancer are mainly undocumented. This research desires to explore the clinical significance, biological function, and mechanism of Lnc_ASNR (apoptosis suppressing-non-coding RNA) in GC. Cell proliferation, cell cycle, cell migration, and invasion abilities were respectively determined by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT), flow cytometry, wound healing, and Transwell assay (Sigma-Aldrich, St. Louis, MO, United States). The association of Lnc_ASNR, miR-519e-5p, and fibroblast growth factor receptor 2 (FGFR2) was evaluated via luciferase reporter experiments. The tumor xenograft assay was conducted to confirm the results of cell experiments. High expressed Lnc_ASNR was detected in both GC cells and tissues using qRT-PCR. Downregulated Lnc_ASNR could reduce proliferation, migration, and invasion in GC cells, while upregulated Lnc_ASNR could promote the cell proliferation, migration, and invasion. Moreover, the effect of Lnc_ASNR on migration and invasion ability is closely related to epithelial-mesenchymal transition (EMT). The bioinformatics analysis, luciferase assay, and Western blot demonstrated that Lnc_ASNR inhibited miR-519e-5p expression but increased FGFR2 expression. Lnc_ASNR and FGFR2 were both targeted to miR-519e-5p, and they were negatively correlated with the expression of miR-519e-5p. All investigations indicated that Lnc_ASNR functioned as a ceRNA targeting miR-519e-5p and facilitated GC development by regulating the pathway of miR-519e-5p/FGFR2.

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.

Inhibition of circRNA circVPS33B Reduces Warburg Effect and Tumor Growth Through Regulating the miR-873-5p/HNRNPK Axis in Infiltrative Gastric Cancer

Background

Circular RNA VPS33B (circVPS33B) has been revealed to be upregulated in gastric cancer (GC) tissues. However, the role of circVPS33B in infiltrative GC is indistinct.

Methods

Expression of circVPS33B was detected using quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, migration, and invasion of infiltrative GC cells (XGC-1) were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT), plate clone, wound-healing, or transwell assays. Protein levels were detected by Western blotting. Measurements of extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were executed using an XF96 extracellular flux analyzer. Glucose uptake and lactate production were analyzed by glycolysis assay. The regulatory mechanism of circVPS33B had been explored by bioinformatics analysis, dual-luciferase reporter assay, and/or RNA pull-down assay. In vivo tumorigenesis assay was executed to verify the oncogenicity of circVPS33B.

Results

CircVPS33B was upregulated in infiltrative GC tissues and cells. CircVPS33B silencing decreased tumor growth in vivo and inhibited proliferation, migration, invasion, EMT, and Warburg effect of infiltrative GC cells in vitro. Mechanically, circVPS33B regulated heterogeneous nuclear ribonucleoprotein K (HNRNPK) expression via sponging miR-873-5p. Furthermore, miR-873-5p inhibitor offset circVPS33B knockdown-mediated effects on malignant behaviors and Warburg effect of infiltrative GC cells. HNRNPK overexpression reversed the inhibitory impact of miR-873-5p mimic on malignant behaviors and Warburg effect of infiltrative GC cells.

Conclusion

CircVPS33B accelerated Warburg effect and tumor growth through regulating the miR-873-5p/HNRNPK axis in infiltrative GC, manifesting that circVPS33B might be a potential target for infiltrative GC treatment.

Silenced lncRNA DDX11-AS1 or up-regulated microRNA-34a-3p inhibits malignant phenotypes of hepatocellular carcinoma cells via suppression of TRAF5

Background

Studies have discussed long noncoding RNA DDX11-AS1 (DDX11-AS1)-mediated downstream mechanism in hepatocellular carcinoma (HCC). The goal of this study was to investigate the regulatory mechanism of DDX11-AS1-mediated microRNA-34a-3p (miR-34a-3p)/tumor necrosis factor receptor-associated factor 5 (TRAF5) axis on HCC cells.

Methods

DDX11-AS1, miR-34a-3p and TRAF5 expression levels in HCC were detected. The correlation of DDX11-AS1, miR-34a-3p and TRAF5 in HCC patients was analyzed by Pearson test. HCC cells were transfected with corresponding plasmid/oligonucleotide, and cell proliferation, migration, invasion, apoptosis and tumor formation ability were detected. Bioinformatics software, dual luciferase report experiment and RNA-pull down experiment analysis were applied to verify the targeting relationship between DDX11-AS1, miR-34a-3p and TRAF5.

Results

Elevated DDX11-AS1 and TRAF5 and reduced miR-34a-3p exhibited in HCC. Silenced DDX11-AS1 or up-regulated miR-34a-3p inhibited the proliferation, migration, invasion, promoted apoptosis of HCC cells and repressed the tumor growth in nude mice. In addition, DDX11-AS1 bound to miR-34a-3p to target TRAF5. Silencing TRAF5 or elevating miR-34a-3p expression mitigated up-regulated DDX11-AS1-mediated promotion of tumor growth.

Conclusion

Silenced DDX11-AS1 or up-regulated miR-34a-3p inhibits HCC cell growth via elevation of TRAF5, which could be of great benefit to find early diagnostic markers for HCC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01847-6.

MiR-873-5p modulates progression of tongue squamous cell carcinoma via targeting SEC11A

OBJECTIVE

To explore the effect of miR-873-5p on proliferation, apoptosis, migration, and invasion of tongue squamous cell carcinoma (TSCC) by targeting SEC11A.

METHODS

Tongue squamous cell carcinoma tissues were collected and performed by qRT-PCR and Western blotting to determine the expression of miR-873-5p and SPC18. SCC9 and CAL-27 cells were transfected and divided into Mock, mimic NC, miR-873-5p mimic, SEC11A, and miR-873-5p mimic + SEC11A groups. Then, a series of experiments including cell count kit 8 (CCK-8), wound healing, Transwell, and flow cytometry were conducted. Besides, Western blotting was used to detect the expression of SPC18 and EGFR pathway-related proteins.

RESULTS

MiR-873-5p was downregulated while SPC18 was upregulated in TSCC, and miR-873-5p was negatively correlated with SPC18. Dual luciferase reporter gene assay confirmed SEC11A to be a target of miR-873-5p. Cell proliferation, migration, and invasion of SCC9 and CAL-27 cells in miR-873-5p mimic group were decreased with increased cell apoptosis, presenting with downregulations of SPC18 and EGFR pathway-related proteins, while cells in SEC11A group manifested totally different changes. Moreover, the inhibitory effect of miR-873-5p mimic on TSCC cell growth was abolished by SEC11A overexpression.

CONCLUSION

Overexpression of miR-873-5p may suppress cell proliferation, migration, and invasion, but facilitate apoptosis in TSCC via targeting SEC11A.

A novel three-long noncoding RNA risk score system for the prognostic prediction of triple-negative breast cancer

Background: Triple-negative breast cancer (TNBC) is characterized by fast tumor increase, rapid recurrence and natural metastasis. We aimed to identify a genetic signature for predicting the prognosis of TNBC. Materials & methods: We conducted a weighted correlation network analysis of datasets from the Gene Expression Omnibus. Multivariate Cox regression was used to construct a risk score model. Results: The multi-factor risk scoring model was meaningfully associated with the prognosis of patients with TBNC. The predictive power of the model was demonstrated by the time-dependent receiver operating characteristic curve and Kaplan-Meier curve, and verified using a validation set. Conclusion: We established a long noncoding RNA-based model for the prognostic prediction of TNBC.

LncRNA CTBP1-AS2 Facilitates Gastric Cancer Progression via Regulating the miR-139-3p/MMP11 Axis

Background

This study aimed at probing into the effect of long non-coding RNA (lncRNA) C-terminal binding protein 1 antisense RNA 2 (CTBP1-AS2) on gastric cancer (GC) cell proliferation and apoptosis, and its regulatory function on miR-139-3p and MMP11.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to examine the expressions of CTBP1-AS2, miR-139-3p and MMP11 mRNA in GC cell lines and clinical specimens. Cell counting kit-8 (CCK-8) assay, flow cytometry and EdU assay were conducted to examine the effects of CTBP1-AS2 and miR-139-3p on GC cell proliferation and apoptosis. Western blot was applied for detecting the expressions of Bax, Bcl-2 and MMP11. A lung metastasis mouse model was used to evaluate metastasis of GC cells in vivo. Bioinformatics, dual-luciferase report assay, RIP and RNA pull-down assays were utilized to validate the targeted relationship between CTBP1-AS2 and miR-139-3p as well as the targeting relationship between miR-139-3p and MMP11.

Results

CTBP1-AS2 was highly expressed in GC, and its high expression was strongly associated with increased TNM stage, increased tumor size and low degree of differentiation of the tumor tissues. Meanwhile, CTBP1-AS2 promoted GC cell proliferation, metastasis and suppressed apoptosis, while miR-139-3p could weaken these effects. In addition, CTBP1-AS2 was identified as a molecular sponge for miR-139-3p, and MMP11 was verified as a target gene of CTBP1-AS2. CTBP1-AS2 could increase the expression of MMP11 via repressing miR-139-3p.

Conclusion

CTBP1-AS2 promotes GC cells and inhibits apoptosis by regulating the miR-139-3p/MMP11 molecular axis.

Dyregulation of the lncRNA TPT1-AS1 positively regulates QKI expression and predicts a poor prognosis for patients with breast cancer

The long noncoding RNA (lncRNA) TPT1-AS1 has been reported to be involved in the development of multiple cancers. However, its clinical value, biological function, and underlying molecular mechanism in breast cancer (BC) remain unclear. In the present study, TPT1-AS1 expression was decreased in BC tissues, based on RNA-seq data download from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and the qRT-PCR results confirmed the above findings. Otherwise, low TPT1-AS1 expression was significantly associated with some clinical features of malignancy, such as high TNM stage, lymph node metastasis, a Her-2-negative status, and shorter overall survival. More importantly, univariate and multivariate Cox regression analyses indicated that TPT1-AS1 is an independent prognostic factor for patients with BC. Overexpression and knockdown of TPT1-AS1 in BC cell lines altered their proliferation, metastasis and invasion, as measured using the cell counting kit-8 (CCK-8) assay, wound-healing assay and transwell assay, respectively. In addition, a dual luciferase activity reporter assay validated that TPT1-AS1 and QKI shared a binding site in miR-330-3p. Based on these findings, TPT1-AS1 potentially represents a prognostic biomarker for patients with BC and participates in the development of BC through the TPT1-AS1/miR-330-3p/QKI axis.

LncRNA DDX11-AS1: a novel oncogene in human cancer

Long noncoding RNA (lncRNA) is a newly identified type of noncoding RNA with a length of more than 200 nucleotides. The latest research shows that lncRNAs play important roles in the occurrence and development of human tumours by acting both as carcinogenic genes and as tumour suppressor genes. LncRNAs plays a role in various biological processes, such as cell growth, apoptosis, migration and invasion. The newly discovered lncRNA DDX11-AS1 is abnormally highly expressed in various malignant tumours, such as hepatocellular carcinoma, colorectal cancer, osteosarcoma, bladder cancer, NSCLC and gastric cancer. DDX11-AS1 mainly regulates the expression of related genes through direct or indirect ways to perform its functions in carcinogenicity. These results indicate that DDX11-AS1 may be a marker or therapeutic target of tumours. This review summarizes the biological function and mechanism of DDX11-AS1 in the process of tumour development.

miR-635 targets KIFC1 to inhibit the progression of gastric cancer

Accumulating studies have shown that the dysregulation of microRNAs is related to the carcinogenesis and development of gastric cancer (GC), and the role of miR-635 in GC remains largely unknown. miR-635 and Kinesin Family Member C1 (KIFC1) mRNA expression in GC tissues and paracancerous tissues and cells were detected by quantitative real-time PCR. KIFC1 protein expression in GC tissues and paracancerous normal tissues and cells was detected by immunohistochemistry and western blot. Cell proliferation was monitored by Cell Counting Kit-8 assay and 5-bromo-2′-deoxyuridine assay. Transwell assay was employed to detect the migration and invasion of GC cells. The dual-luciferase reporter gene assay was adopted to detect the targeting relationship between miR-635 and KIFC1. Compared with paracancerous tissues, miR-635 expression was remarkably decreased in GC tissues; conversely, KIFC1 expression was significantly increased. Compared with human normal gastric epithelial cell GSE-1, miR-635 expression was markedly decreased in GC cell lines. Meanwhile, KIFC1 expression was significantly increased, and the Kaplan-Meier Plotter database showed that its high expression was remarkably associated with poor prognosis. Additionally, miR-635 can negatively regulate KIFC1. miR-635 can target KIFC1 to inhibit proliferation, migration and invasion of GC cells. Collectively, miR-635 is lowly expressed in GC, and it inhibits proliferation, migration and invasion of GC cells via regulating KIFC1.

lncRNA expression profiles related to apoptosis and autophagy in peripheral blood mononuclear cells of patients with rheumatoid arthritis

Long noncoding RNAs (lncRNAs) are >200-bp molecules that do not generally code for proteins. Human lncRNAs have well-characterized roles in gene expression regulation, particularly with regard to protein-coding genes, and their dysregulation has been linked to disease. Here, we set out to investigate changes in the expression of lncRNAs related to apoptosis and autophagy in the peripheral blood mononuclear cells (PBMCs) of rheumatoid arthritis (RA). In addition, we aimed to correlate lncRNA expression profiles with clinical indexes and self-perception of patients (SPP). To this end, we employed RNA sequencing of lncRNAs in PBMCs from three patients with RA and three healthy controls. We used bioinformatics to screen several dysregulated lncRNAs related to apoptosis and autophagy. To validate key lncRNA candidates, we performed quantitative reverse transcriptase-PCR on 20 patients with RA and 20 healthy controls. We found the expression of seven lncRNAs (MAPKAPK5-AS1, ENST00000619282, C5orf17, LINC01189, LINC01006, DSCR9 and MIR22HG) was significantly altered in PBMCs of patients with RA. Receiver operating characteristic curve analysis suggested that MIR22HG [area under the curve (AUC) = 0.846, P = 0.000], DSCR9 (AUC = 0.783, P = 0.005), LINC01189 (AUC = 0.677, P = 0.034), MAPKAPK5-AS1 (AUC = 0.644, P = 0.025) and ENST00000619282 (AUC = 0.636, P = 0.043) are potential biomarkers of RA. Spearman's correlation analysis revealed selected lncRNAs correlated with clinical indexes and SPP. Therefore, we highlight that some lncRNAs related to apoptosis and autophagy may serve as potential biomarkers for diagnosis and monitoring of RA progression, which also correlate with several clinical indexes and SPP.

Long Intergenic Non-Protein Coding RNA 1089 Suppresses Cell Proliferation and Metastasis in Gastric Cancer by Regulating miRNA-27a-3p/Epithelial-Mesenchymal Transition (EMT) Axis

Aim

To explore the expression and biological function of long intergenic non-protein coding RNA 1089 (LINC01089) in gastric cancer (GC) progression and its underlying mechanism.

Methods

LINC01089 and microRNA-27a-3p (miR-27a-3p) expressions were detected with the quantitative real-time polymerase chain reaction (RT-qPCR). Cell proliferation, migration and invasion were evaluated by Cell Counting Kit-8 (CCK-8) and Transwell assay. Epithelial-mesenchymal transition (EMT)-related proteins were also measured by Western blot. The relationship between LINC01089 and miR-27a-3p was revealed by a bioinformatics analysis and dual-luciferase reporter assay.

Results

LINC01089 was significantly down-regulated in GC tissues, as well as GC cell lines. GC patients with lower LINC01089 expression were more likely to have poor outcomes. Overexpression of LINC01089 significantly suppressed GC cells growth, migration and invasion and forbade the EMT process. LINC01089 was directly targeted at miR-27a-3p. The transfection of miR-27a-3p mimics reversed the inhibitory effects on proliferative and metastatic abilities of GC cells with LINC01089 overexpression.

Conclusion

LINC01089 inhibits cell proliferation and metastasis in GC by targeting miR-27a-3p/EMT axis, which should be considered as a promising therapeutic target.

Long non-coding RNA DDX11-AS1 promotes non-small cell lung cancer development via regulating PI3K/AKT signalling

Non-small cell lung cancer (NSCLC) has been considered to be the most common category of lung cancer, comprising approximately 80% of lung cancers. Long non-coding RNAs (lncRNAs) were diffusely documented to modulate carcinogenesis or progression of tumours. However, the role of DDX11-AS1 was still unclear in NSCLC. Bioinformatics analysis and experimental assays including hematoxylin and eosin (H&E) staining, RT-qPCR, colony formation, CCK-8, flow cytometry, western blot and xenograft assays were applied to investigate the biological role and molecular mechanism of DDX11-AS1 in NSCLC. The level of lncRNA DDX11-AS1 was up-regulated in NSCLC tumour tissues and cells. In function aspect, knockdown of DDX11-AS1 caused an apparent inhibitive effect on cell proliferation in vitro and in vivo. DDX11-AS1 inhibition promoted cell apoptosis in vitro. In mechanism, the protein level of phosphorylated AKT was reduced by DDX11-AS1 inhibition but increased by DDX11-AS1 overexpression. These results indicated that DDX11-AS1 exacerbated NSCLC progression via activating PI3K/AKT signalling pathway. All in all, DDX11-AS1 promotes NSCLC development via regulating PI3K/AKT signalling.