Long noncoding RNA BC032469, a novel competing endogenous RNA, upregulates hTERT expression by sponging miR-1207-5p and promotes proliferation in gastric cancer

Long Noncoding RNA Lnc-TLN2-4:1 Suppresses Gastric Cancer Metastasis and Is Associated with Patient Survival

Gastric cancer (GC) is one of the most common malignancies worldwide, and the tumor metastasis leads to poor outcomes of GC patients. Long noncoding RNAs (lncRNAs) have emerged as new regulatory molecules that play a crucial role in tumor metastasis. However, the biological function and underlying mechanism of numerous lncRNAs in GC metastasis remain largely unclear. Here, we report a novel lncRNA, lnc-TLN2-4:1, whose expression is decreased in GC tissue versus matched normal tissue, and its low expression is involved in the lymph node and distant metastases of GC, as well as poor overall survival rates of GC patients. We further found that lnc-TLN2-4:1 inhibits the ability of GC cells to migrate and invade but does not influence GC cell proliferation and confirmed that lnc-TLN2-4:1 is mainly located in the cytoplasm of GC cells. We then found that lnc-TLN2-4:1 increases the mRNA and protein expression of TLN2 in GC cells and there is a positive correlation between the expression of lnc-TLN2-4:1 and TLN2 mRNA in GC tissue. Collectively, we identified a novel lncRNA, lnc-TLN2-4:1, in GC, where lnc-TLN2-4:1 represses cell migration and invasion. The low expression of lnc-TLN2-4:1 is associated with poor overall survival rates of GC patients. These suggest that lnc-TLN2-4:1 may be a tumor suppressor during GC metastasis.

Long noncoding RNA TRPM2-AS acts as a microRNA sponge of miR-612 to promote gastric cancer progression and radioresistance

Long noncoding RNAs (lncRNAs) are emerging as important regulators of tumorigenesis and are frequently dysregulated in cancers. Here, we identify a critical lncRNA TRPM2-AS which is aberrantly expressed in gastric cancer (GC) tissues by screening The Cancer Genome Atlas Program(TCGA) database of GC cohort, and its upregulation is clinically associated with advanced pathologic stages and poor prognosis in GC patients. Silencing TRPM2-AS inhibits the proliferation, metastasis and radioresistance of GC cell whereas ectopic expression of TRPM2-AS significantly improves the progression of GC cell in multiple experiments. Mechanistically, TRPM2-AS serves as a microRNA sponge or a competitive endogenous RNA (ceRNA) for tumor suppressive microRNA miR-612 and consequently modulates the derepression of IGF2BP1 and FOXM1. Moreover, induced upregulation of IGF2BP1 subsequently increases the expression of c-Myc and promotes GC cell progression. Meanwhile, TRPM2-AS promotes the radioreistance of GC cell through enhancing the expression of FOXM1 as well. Thus, our findings support a new regulatory axis between TRPM2-AS, miR-612, IGF2BP1, or FOXM1 which serve as crucial effectors in GC tumorigenesis and malignant development, suggesting a promising therapeutic and diagnostic direction for GC.

LncRNA COL1A1-014 is involved in the progression of gastric cancer via regulating CXCL12-CXCR4 axis

BACKGROUND

The aberrant expression of long noncoding RNAs (lncRNAs) is found in various types of cancers and also showed its association with the occurrence and development of gastric cancer (GC). We found lncRNA COL1A1-014 was frequently upregulated in GC.

METHODS

This study investigated COL1A1-014 for its biological function at both cellular and animal levels, using MTT, flow cytometry, colony formation and transwell assays. The expression levels of COL1A1-014 and other genes were detected by RT-PCR and western blot. Luciferase reporter assay was used to detect the potential binding of miR-1273h-5p to COL1A1-014 and CXCL12.

RESULTS

We found that COL1A1-014 was frequently upregulated in GC tissues as well as cells. COL1A1-014 increased cell proliferation, colony forming efficiency, migration ability, invasion ability, and weight and volume of grafted tumors, while reduced cell apoptosis. Overexpression of COL1A1-014 increased the mRNA expression of chemokine (CXCmotif) ligand (CXCL12) and high levels of CXCL12 and CXCR4 proteins in GC cells. The levels of miR-1273h-5p showed an inverse correlation with COL1A1-014 and CXCL12 in GC cells transfected with miR-1273h-5p. The mRNAs of wild-type COL1A1-014 and CXCL12 showed reduction in HEK293 cells transfected with miR-1273h-5p. This suggested that COL1A1-014 functions as an efficient miR-1273h-5p sponge and as a competing endogenous RNA (ceRNA) to regulate CXCL12. The proliferative activity of COL1A1-014 on GC cells was blocked by CXCL12-CXCR4 axis inhibitor AMD-3100.

CONCLUSIONS

These findings demonstrated that COL1A1-014 play an important regulatory role in GC development by functioning as a ceRNA in regulating the CXCL12/CXCR4 axis via sponging miR-1273h-5p.

Discovery of inflammatory bowel disease-associated miRNAs using a novel bipartite clustering approach

BACKGROUND

Multidimensional data mining from an integrated environment of different data sources is frequently performed in computational system biology. The molecular mechanism from the analysis of a complex network of gene-miRNA can aid to diagnosis and treatment of associated diseases.

METHODS

In this work, we mainly focus on finding inflammatory bowel disease (IBD) associated microRNAs (miRNAs) by biclustering the miRNA-target interactions aided by known IBD risk genes and their associated miRNAs collected from several sources. We rank different miRNAs by attributing to the dataset size and connectivity of IBD associated genes in the miRNA regulatory modules from biclusters. We search the association of some top-ranking miRNAs to IBD related diseases. We also search the network of discovered miRNAs to different diseases and evaluate the similarity of those diseases to IBD.

RESULTS

According to different literature, our results show the significance of top-ranking miRNA to IBD or related diseases. The ratio analysis supports our ranking method where the top 20 miRNA has approximately tenfold attachment to IBD genes. From disease-associated miRNA network analysis we found that 71% of different diseases attached to those miRNAs show more than 0.75 similarity scores to IBD.

CONCLUSION

We successfully identify some miRNAs related to IBD where the scoring formula and disease-associated network analysis show the significance of our method. This method can be a promising approach for isolating miRNAs for similar types of diseases.

CFIm25-regulated lncRNA acv3UTR promotes gastric tumorigenesis via miR-590-5p/YAP1 axis

Accumulating evidences indicate that 3ʹUTR of the coding gene can act as crucial regulators in gastric cancer (GC). However, the detailed mechanisms and responsive targets are not well established. Here, we found that acvr1b gene 3ʹUTR (acv3UTR) was elevated in GC tissue, the expression of which was significantly correlated with advanced pTNM-stage and poor outcome in clinical patients. Forced expression of acv3UTR promoted GC cells growth in vitro and in vivo. Mechanistically, our results suggested that acv3UTR functioned as an oncogenic competing endogenous RNA via sponging miR-590-5p and enhancing YAP1 level. Tumor suppressor miR-590-5p was a molecular module in acv3UTR regulatory axis, the forced expression of which led to impairing of oncogenic potential of acv3UTR. The positive correlation of acv3UTR and YAP1 expression, and the negative correlation of acv3UTR and miR-590-5p expression, were verified in GC patients. Moreover, CFIm25 was identified as a key regulator contributing to acv3UTR aberrant expression in GC binding to UGUA-264 motif. Overall, our finding defines a mechanism for understanding the potential role of acv3UTR transcription in GC tumorigenesis, and indicates a correlation between 3ʹUTR trans-regulatory effect and GC development.

Long Non-Coding RNA HULC Promotes Cervical Cancer Cell Proliferation, Migration and Invasion via miR-218/TPD52 Axis

Objective

Long non-coding RNAs (lncRNAs) have been identified as important players in tumorigenesis. LncRNA highly upregulated in liver cancer (HULC) has been identified as a key regulator in the progression of various cancers. However, the functional role and the mechanisms of HULC in regulating cervical cancer cell behavior remain unclear.

Methods

HULC expression, miR-218 expression and TPD52 mRNA level in cervical cancer cells were examined by qRT-PCR. Cell proliferation was evaluated by MTT assay. Cell migration and invasion were examined by Transwell assay. TPD52 protein level was measured by Western blot. Dual-luciferase reporter assay was measured to verify the combination of HULC and miR-218 as well as miR-218 and TPD52.

Results

HULC expression was upregulated in cervical cancer cell lines, and HULC promoted cervical cancer cell proliferation, migration and invasion. Mechanistically, HULC acted as a sponge of miR-218 to elevate expression of TPD52, a target of miR-218, and thereby promoted cervical cancer cell proliferation, migration, and invasion.

Conclusion

HULC promotes cervical cancer cell proliferation, migration and invasion via miR-218/TPD52 axis.

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.

LncRNA CR749391 acts as a tumor suppressor to upregulate KLF6 expression via interacting with miR-181a in gastric cancer

Long non-coding RNAs (lncRNAs) are novel regulators for post-transcriptional gene expression, and altered lncRNAs function and expression are associated with tumorigenesis and cancer progression, although the biological functions of most lncRNAs in various cancer types and their underlying regulatory interactions have remained largely elusive. Our previous study identified microRNA (miR)-181a as a regulator of Kruppel-like factor 6 (KLF6). In the present study, a bioinformatical analysis was performed to identify the novel lncRNA CR749391 as a potential regulator of miR-181a that contains four putative binding sites. Subsequent in vitro experiments in gastric cancer (GC) cells demonstrated that CR749391 interacted with miR-181a to regulate KLF6 expression. First, a direct binding interaction was confirmed using luciferase reporter and RNA immunoprecipitation and pull-down assays. In addition, CR749391 was observed to be downregulated in GC compared with that of normal gastric cell lines. A functional study also revealed that CR749391 depletion in normal gastric epithelial cells promoted cell viability, migration and invasion, and conferred resistance to apoptosis, whereas ectopic CR749391 overexpression had the opposite effect in GC cells and inhibited in vivo tumor growth. In addition, CR749391 was observed to be downregulated in GC compared with that of normal gastric tissues, which was associated with KLF6 but inversely associated with miR-181a levels. Overall, the CR749391/miR-181a regulatory interaction and association between CR749391 and KLF6 may enhance the current understanding of GC pathogenesis, although CR749391 association with GC prognosis needs further study. The current study could provide a novel approach for lncRNA-mediated targeted GC therapy.

Research progress on the interactions between long non-coding RNAs and microRNAs in human cancer

Numerous types of molecular mechanisms mediate the development of cancer. Non-coding RNAs (ncRNAs) are being increasingly recognized to play important role in mediating the development of diseases, including cancer. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are the two most widely studied ncRNAs. Thus far, lncRNAs are known to have biological roles through a variety of mechanisms, including genetic imprinting, chromatin remodeling, cell cycle control, splicing regulation, mRNA decay and translational regulation, and miRNAs regulate gene expression through the degradation of mRNAs and lncRNAs. Although ncRNAs account for a major proportion of the total RNA, the mechanisms underlying the physiological or pathological processes mediated by various types of ncRNAs, and the specific interaction mechanisms between miRNAs and lncRNAs in various physiological and pathological processes, remain largely unknown. Thus, further research in this field is required. In general, the interaction mechanisms between miRNAs and lncRNAs in human cancer have become important research topics, and the study thereof has led to the recent development of related technologies. By providing examples and descriptions, and performing chart analysis, the present study aimed to review the interaction mechanisms and research approaches for these two types of ncRNAs, as well as their roles in the occurrence and development of cancer. These details have far-reaching significance for the utilization of these molecules in the diagnosis and treatment of cancer.

LncRNA-HGBC stabilized by HuR promotes gallbladder cancer progression by regulating miR-502-3p/SET/AKT axis

BACKGROUNDS

Long non-coding RNAs (lncRNAs) are essential factors that regulate tumor development and metastasis via diverse molecular mechanisms in a broad type of cancers. However, the pathological roles of lncRNAs in gallbladder carcinoma (GBC) remain largely unknown. Here we discovered a novel lncRNA termed lncRNA Highly expressed in GBC (lncRNA-HGBC) which was upregulated in GBC tissue and aimed to investigate its role and regulatory mechanism in the development and progression of GBC.

METHODS

The expression level of lncRNA-HGBC in GBC tissue and different cell lines was determined by quantitative real-time PCR. The full length of lncRNA-HGBC was obtained by 5' and 3' rapid amplification of the cDNA ends (RACE). Cellular localization of lncRNA-HGBC was detected by fluorescence in situ hybridization (FISH) assays and subcellular fractionation assay. In vitro and in vivo assays were preformed to explore the biological effects of lncRNA-HGBC in GBC cells. RNA pull-down assay, mass spectrometry, and RNA immunoprecipitation (RIP) assay were used to identify lncRNA-HGBC-interacting proteins. Dual luciferase reporter assays, AGO2-RIP, and MS2-RIP assays were performed to verify the interaction between lncRNA-HGBC and miR-502-3p.

RESULTS

We found that lncRNA-HGBC was upregulated in GBC and its upregulation could predict poor survival. Overexpression or knockdown of lncRNA-HGBC in GBC cell lines resulted in increased or decreased, respectively, cell proliferation and invasion in vitro and in xenografted tumors. LncRNA-HGBC specifically bound to RNA binding protein Hu Antigen R (HuR) that in turn stabilized lncRNA-HGBC. LncRNA-HGBC functioned as a competitive endogenous RNA to bind to miR-502-3p that inhibits target gene SET. Overexpression, knockdown or mutation of lncRNA-HGBC altered the inhibitory effects of miR-502-3p on SET expression and downstream activation of AKT. Clinically, lncRNA-HGBC expression was negatively correlated with miR-502-3p, but positively correlated with SET and HuR in GBC tissue.

CONCLUSIONS

Our study demonstrates that lncRNA-HGBC promotes GBC metastasis via activation of the miR-502-3p-SET-AKT cascade, pointing to lncRNA-HGBC as a new prognostic predictor and a therapeutic target.

Calcium-sensing receptor bridges calcium and telomerase reverse transcriptase in gastric cancers via Akt

PURPOSE

Human telomerase reverse transcriptase (hTERT) and calcium-sensing receptor (CaSR) act as an oncogene in gastric cancers, however, their relationship in the progression of gastric cancers is yet to be elucidated. Herein, we aimed to access the potential interaction between hTERT and CaSR in the development of gastric cancers.

METHODS

The clinical data of 41 patients with gastric cancers were analyzed regarding the expressions of hTERT and CaSR by immunohistochemistry. Among them, five patients' specimens were also analyzed by Western blotting. The regulation of calcium on the expression level of hTERT and the possible underlying mechanism via CaSR were explored in gastric cancer cell lines MKN45 and SGC-7901.

RESULTS

Both hTERT and CaSR were increased and positively correlated in human gastric cancers, which also occurs in gastric cancer cells MKN45 and SGC-7901. Calcium induced hTERT expression at the transcriptional level in a CaSR-dependent manner followed by an increase in telomerase activity, as either a CaSR shRNA or the CaSR antagonist NPS2143 abolished the calcium-mediated regulation of hTERT and telomerase activity. Further studies showed that CaSR-mediated cytosolic calcium rise followed by Akt activation was involved in the regulation of hTERT by extracellular calcium. Finally, neither CaSR overexpression nor shRNA-mediated CaSR downregulation had an effect on the expression level of hTERT.

CONCLUSIONS

Our findings established a functional linkage between CaSR and hTERT in the development of gastric cancers and CaSR-hTERT coupling might serve as a novel target for therapeutic strategy against human gastric cancers.

Differentially expressed long noncoding RNAs and regulatory mechanism of LINC02407 in human gastric adenocarcinoma

BACKGROUND

Long noncoding RNAs (lncRNAs) have been identified to play important roles in the development and progression of various tumors, including gastric cancer (GC). However, the molecular role of lncRNAs in GC progression remains unclear.

AIM

To investigate the differential expression of lncRNAs in human GC and elucidate the function and regulatory mechanism of LINC02407.

METHODS

The Cancer Genome Atlas database was used to investigate the involvement of lncRNAs in GC. Quantitative real-time polymerase chain reaction was used to estimate the relative expression level of LINC02407 in GC tissues and cells. Functional experiments including CCK8 assay, apoptosis assay, wound healing assay, and transwell assay were used to investigate the effect of LINC02407 on GC cells. Some microRNAs were predicted and verified via bioinformatics analysis and the luciferase reporter system. Predictive analysis and Western blot assay were used to analyze the expression of related proteins.

RESULTS

Many differentially expressed lncRNAs were identified in GC, and some of them including LINC02407 can affect the survival. LINC02407 was upregulated in tumor tissues compared with adjacent tissues. HGC-27 cells showed the highest LINC02407 expression and HaCaT cells exhibited the lowest expression. Different experiment groups were constructed using LINC02407 overexpressing plasmids and related siRNAs. The results of functional experiments showed that LINC02407 can promote the proliferation, migration, and invasion of GC cells but inhibit apoptosis. Luciferase reporter assay showed that hsa-miR-6845-5p and hsa-miR-4455 was downstream regulated by LINC02407. Western blot analysis showed that adhesion G protein-coupled receptor D1 (ADGRD1) was regulated by the LINC02407-miR-6845-5p/miR-4455-ADGRD1 pathways.

CONCLUSION

LINC02407 plays a role in GC through the LINC02407-miR-6845-5p/miR-4455-ADGRD1 pathways, and thus, it may be an important oncogene and has potential value in GC diagnosis and treatment.

Comprehensive Analysis of the mRNA-lncRNA Co-expression Profile and ceRNA Networks Patterns in Chronic Hepatitis B

Background:

Long non-coding RNAs (lncRNAs) are emerging as important regulators in the modulation of virus infection by targeting mRNA transcription. However, their roles in chronic hepatitis B (CHB) remain to be elucidated.

Objective:

The study aimed to explore the lncRNAs and mRNA expression profiles in CHB and asymp-tomatic HBsAg carriers (ASC) and construct mRNA-lncRNA co-expression profile and ceRNA net-works to identify the potential targets of diagnosis and treatment in CHB.

Methods:

We determined the expression profiles of lncRNAs and mRNAs in CHB and ASC using mi-croarray analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) path-way enrichment analyses were performed to explore their function. We also constructed co-expression, cis-regulatory, and competing endogenous RNA (ceRNA) networks with bioinformatics methods.

Results:

We identified 1634 mRNAs and 5550 lncRNAs that were differentially expressed between CHB and ASC. Significantly enriched GO terms and pathways were identified, many of which were linked to immune processes and inflammatory responses. Co-expression analysis showed 1196 relation-ships between the top 20 up/downregulated lncRNAs and mRNA, especially 213 lncRNAs interacted with ZFP57. The ZFP57-specific ceRNA network covered 3 lncRNAs, 5 miRNAs, and 17 edges. Cis-correlation analysis showed that lncRNA T039096 was paired with the most differentially expressed gene, ZFP57. Moreover, by expending the clinical samples size, the qRT-PCR results showed that the expression of ZFP57 and T039096 increased in CHB compared to ASC.

Conclusion:

Our study provides insights into the roles of mRNA and lncRNA networks in CHB, high-lighting potential applications of lncRNA-T039096 and mRNA-ZFP57 for diagnosis and treatment.

Long non‑coding RNA MEG3 suppresses the growth of glioma cells by regulating the miR‑96‑5p/MTSS1 signaling pathway

Glioma is one of the most common types of tumor of the central nervous system with high mobility and mortality. The prognosis of patients with high-grade glioma is poor. Therefore, it is urgent to develop the therapeutic strategies for the treatment of glioma. Long non-coding RNAs (lncRNAs) have been reported as potential inducers or suppressors of numerous types of tumors including glioma. Previous studies have revealed that lncRNA maternally expressed gene 3 (MEG3) is involved in the initiation and progression of cancer; however, the underlying mechanisms remain unclear. In the present study, MEG3 was downregulated in glioma tissue. In addition, downregulation of MEG3 was observed in human glioma cell lines compared with normal astrocyte cells. Furthermore, overexpressed MEG3 inhibited the proliferation, migration and invasion of glioma cells. Additionally, microRNA-96-5p (miR-96-5p) was a promising target of MEG3, and the promoting effects of miR-96-5p on cell growth and metastasis could be reversed by upregulated MEG3. Metastasis suppressor 1 (MTSS1) was predicted as the putative target of miR-96-5p, and its expression was restored by MEG3. In summary, the present data provided novel insight into the roles of MEG3 in glioma, and MEG3/miR-96-5p/MTSS1 signaling could be a promising therapeutic target for the treatment of patients with glioma.

lncRNA ROR promotes the progression of renal cell carcinoma through the miR‑206/VEGF axis

Renal cell carcinoma (RCC) is the most common kidney malignancy, responsible for ~80% of all cases in adults. The pathogenesis of RCC is complex, involving alterations at both the genetic and epigenetic levels. Numerous signaling pathways, such as PI3K/Akt/mTOR and Wnt‑β‑catenin have been demonstrated to be associated with the tumorigenesis and development of RCC. Long non‑coding RNAs (lncRNAs) are functional RNA molecules involved in the initiation and progression of cancer, and investigating the effects of lncRNA could facilitate the development of novel treatments. The lncRNA regulator of reprogramming (ROR) is aberrantly expressed in a variety of tumors. However, its underlying mechanisms remain largely unknown. In the present study, ROR was found to be upregulated and microRNA (miR)‑206 was found to be downregulated in RCC tissues and cells. Furthermore, the knockdown of ROR inhibited the proliferation, migration and invasion of RCC cells. It was found that ROR binds to miR‑206, and that ROR‑induced cell proliferation and metastasis were reversed by the overexpression of miR‑206. In addition, the levels of miR‑206 and ROR were negatively correlated in RCC tissues. Furthermore, the overexpression of miR‑206 notably suppressed the proliferation, migration and invasion of RCC cells, and these effects were enhanced by the knockdown of vascular endothelial growth factor (VEGF); cell growth and metastasis induced by miR‑206 inhibitors could be reversed by the knockdown of VEGF. In addition, the expression levels of miR‑206 and VEGF were inversely correlated in RCC samples. In summary, the results of the present study revealed that ROR was upregulated in RCC tissues, which promoted tumor progression by regulating the miR‑206/VEGF axis. The present findings provided a novel insight into the potential functions of ROR in RCC, and the ROR/miR‑206/VEGF pathway may be a promising therapeutic target for the treatment of patients with RCC.

A SOX9-AS1/miR-5590-3p/SOX9 positive feedback loop drives tumor growth and metastasis in hepatocellular carcinoma through the Wnt/β-catenin pathway

Hepatocellular carcinoma (HCC) is a prevalent solid tumor with a high global death rate. SRY box 9 (SOX9) has been reported as an oncogene in HCC by several studies, but the underlying mechanism remains largely unexplored. Here, we confirmed upregulation of SOX9 in HCC tissues and cell lines and validated that SOX9 facilitates proliferation, migration and invasion in HCC. We subsequently identified that the long non‐coding RNA (lncRNA) SOX9 antisense RNA 1 (SOX9‐AS1) is a neighbor gene to SOX9; SOX9‐AS1 is also upregulated in HCC, and its expression is positively correlated with that of SOX9. In addition, SOX9‐AS1 appears to have prognostic significance in HCC patients. We showed that SOX9‐AS1 aggravates HCC progression and metastasis in vitro and in vivo. We demonstrated that SOX9‐AS1 sponges miR‐5590‐3p to elevate SOX9 expression, and that SOX9 in turn transcriptionally activates SOX9‐AS1. Moreover, we verified that SOX9‐AS1 regulates SOX9 and its known downstream Wnt/β‐catenin pathway so as to facilitate epithelial‐to‐mesenchymal transition. The results of our rescue assays suggest that SOX9‐AS1 regulates HCC progression through SOX9 and the Wnt/β‐catenin pathway. In conclusion, our study demonstrates that a SOX9‐AS1/miR‐5590‐3p/SOX9 positive feedback loop drives tumor growth and metastasis in HCC through the Wnt/β‐catenin pathway, suggesting SOX9‐AS1 as a novel potential prognostic and treatment target for HCC.

Long non-coding RNA KRT19P3 suppresses proliferation and metastasis through COPS7A-mediated NF-κB pathway in gastric cancer

Long non-coding RNAs (lncRNAs) have emerged as critical regulators in gastric cancer (GC). LncRNA expression microarray data indicate that KRT19P3 (Keratin 19 Pseudogene 3) is downregulated in GC samples. However, the expression pattern and molecular mechanism of KRT19P3 in GC have not been characterized. The present study confirmed the downregulation of KRT19P3 in GC tissues and cells. Decreased expression of KRT19P3 was correlated with larger tumor size, advanced TNM stage, Lauren's classification, positive lymph node metastasis, and poor prognosis. Enforced expression of KRT19P3 significantly inhibited cell proliferation, migration, and invasion in vitro, as well as tumorigenesis and metastasis in vivo. Conversely, KRT19P3 knockdown had opposite effects. Mechanistically, RNA pull-down and RNA immunoprecipitation assay revealed that KRT19P3 could directly bind COPS7A. KRT19P3 enhanced COPS7A protein stability in GC cells, and KRT19P3 suppressed GC cell proliferation and metastasis partly through regulation of COPS7A expression. COPS7A could promote deubiquitinylation of IκBα, which was executed by CSN-associated deubiquitinylase USP15, and then KRT19P3 inactivated nuclear factor kappa-B (NF-κB) signaling pathway in a COPS7A-dependent manner. For the first time, we revealed that KRT19P3 could suppress tumor growth and metastasis through COPS7A-mediated NF-κB pathway, which may serve as potential targets for treatment of GC in the future.

FOXP1-induced lncRNA CLRN1-AS1 acts as a tumor suppressor in pituitary prolactinoma by repressing the autophagy via inactivating Wnt/β-catenin signaling pathway

As the commonest type of functional pituitary tumor, prolactinoma takes up around 40-60% of functional pituitary tumors. Despite dedications attributed to the treatment of prolactinoma, complete cure remains difficult. Hence, it is of significance to bring to light the underlying mechanism of prolactinoma. Long noncoding RNAs (lncRNAs) are a group of transcripts which can regulate various biological processes. In the present study, we explored an lncRNA that was differentially downregulated in prolactinoma samples. LncRNA clarin 1 antisense RNA 1 (CLRN1-AS1) was downregulated in 42 patient samples and inactivated the Wnt/β-catenin signaling pathway. Functionally, CLRN1-AS1 suppressed cell proliferation, promoted apoptosis, and inhibited autophagy. Subcellular fractionation assay revealed that CLRN1-AS1 was located in the cytoplasm of prolactinoma cells. Based on bioinformatics analysis and mechanism experiments, we determined that CLRN1-AS1 acted as a competing endogenous RNA (ceRNA) by sponging miR-217 to upregulate the dickkopf WNT signaling pathway inhibitor 1 (DKK1). Furthermore, Forkhead box P1 (FOXP1) was verified to be a transcription suppressor of CLRN1-AS1. In summary, this study revealed that FOXP1-induced CLRN1-AS1 regulated cellular functions in pituitary prolactinoma by sponging miR-217 to release the DKK1/Wnt/β-catenin signaling pathway.

Diverse regulatory manners of human telomerase reverse transcriptase

Human telomerase reverse transcriptase (hTERT) is the core subunit of human telomerase and plays important roles in human cancers. Aberrant expression of hTERT is closely associated with tumorigenesis, cancer cell stemness maintaining, cell proliferation, apoptosis inhibition, senescence evasion and metastasis. The molecular basis of hTERT regulation is highly complicated and consists of various layers. A deep and full-scale comprehension of the regulatory mechanisms of hTERT is pivotal in understanding the pathogenesis and searching for therapeutic approaches. In this review, we summarize the recent advances regarding the diverse regulatory mechanisms of hTERT, including the transcriptional (promoter mutation, promoter region methylation and histone acetylation), post-transcriptional (mRNA alternative splicing and non-coding RNAs) and post-translational levels (phosphorylation and ubiquitination), which may provide novel perspectives for further translational diagnosis or therapeutic strategies targeting hTERT.

Long non-coding RNA-HAGLR suppressed tumor growth of lung adenocarcinoma through epigenetically silencing E2F1

Emerging evidence indicates that long noncoding RNAs (LncRNAs) are new players in gene regulation but their mechanisms of action are mainly undocumented. In this study, we investigated LncRNA alterations that contribute to lung cancer by analyzing published microarray data in Gene Expression Obminus (GEO) and The Cancer Genome Atlas RNA (TCGA) sequencing data. Here, we reported that HAGLR (also called HOXD-AS1) was frequently down-regulated in lung adenocarcinoma (LUAD) tissues, and decreased HAGLR expression was clinically associated with shorter survival of LUAD patients. Preclinical studies using multiple LUAD cells and in vivo mouse model indicated that HAGLR could attenuate LUAD cell growth in vitro and in vivo. Mechanistically, HAGLR could physically interact with DNMT1, and recruit DNMT1 on E2F1 promoter to increase local DNA methylation. Overall, our study demonstrated that HAGLR promoted LUAD progression by recruiting DNMT1 to modulate the promoter methylation and expression of E2F1, which expanded potential therapeutic strategies for LUAD treatment.

Transcript-level regulation of MALAT1-mediated cell cycle and apoptosis genes using dual MEK/Aurora kinase inhibitor "BI-847325" on anaplastic thyroid carcinoma

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is the most lethal malignancy in thyroid carcinomas. Long non-coding RNAs (lncRNAs) are a member of non-coding RNAs, regulating the expression of gene. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is an onco-lncRNA that is overexpressed in several carcinomas including ATC. Evidence showed that MALAT1 has a crucial function in apoptosis, and cell cycle progression.

OBJECTIVES

In order to take advantage of 3D cell culture system in cancer investigation, we have used a 3D in vitro ATC model to determine the effect of dual MEK/Aurora kinase inhibitor BI-847325 anticancer drug on the fundamental molecular mechanisms of MALAT1-mediated gene regulation in ATC.

METHODS

In this study, ATC cell lines (C643 and SW1736) were grown in alginate scaffold. Encapsulated cells were treated by BI-847325. Changes in expression of MALAT1, Mcl1, miR-363-3p, and cyclinD1 were measured by qRT-PCR.

RESULTS AND CONCLUSION

MALAT1 gene expression following BI-847325 treatment was significantly downregulated in C643 and SW1736 cell lines. Reversely, miR-363-3p expression was significantly upregulated by BI-847325 in both ATC cell lines. Mcl1 expression was significantly downregulated after treatment in C643 cell lines. Moreover, the expression of this gene was not significantly reduced following BI-847325 treatment in SW1736 cell line. Additionally, cyclin D1 expression was significantly downregulated after treatment in both ATC cell lines. Altogether, the result of this study was the first report of MALAT1's molecular function in ATC and suggested that BI-847325 which inhibits both MEK and Aurora kinase family could be effective against ATC by regulating the genes involved in cell cycle and apoptosis including MALAT1and its downstream genes. Graphical abstract Schematic representation of the biological role of MALAT1 in cyclin D1, miR-363-3p and Mcl1 gene regulations. Stimulation of receptor tyrosine kinase (RTK) by growth factors (GFs) phosphorylates RAS that subsequently activates RAF. Then, RAF phosphorylates MEK. Consequently, activated MEK phosphorylates ERK downstream effector, leading to the MALAT1 gene expression. MALAT1 is a negative regulator of Mcl1 mRNA by sponging of miR-363-3p. In addition, MALAT1 leads to Axin1 and APC downregulation and Wnt/β-catenin signaling pathway activation. Stable β-catenin translocates from the cytoplasm to the nucleus and promotes cyclin D1 gene expression.

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.

Long noncoding RNA MIR31HG is activated by SP1 and promotes cell migration and invasion by sponging miR-214 in NSCLC

Long non-coding RNAs(lncRNAs) have been reported to play pivotal roles in various cancers. Recently, MIR31HG was proposed to be involved in tumor progression. However, its role in non small cell lung cancer(NSCLC) remains elusive. In this work, we found that SP1-induced MIR31HG was significantly upregulated in NSCLC tissues and cell lines. Moreover, Cox multivariate survival analysis revealed that high MIR31HG was an independent predictor of poor overall survival(OS). Functionally, knockdown of TINCR obviously suppressed NSCLC cells migration and invasion in vitro and inhibited NSCLC cells metastasis in vivo. Mechanistically, we identified MIR31HG could act as a miR-214 sponge using RNA pull down, luciferase reporter and RIP assays. Lastly, we verified that overexpression of MIR31HG effectively reverses miR-214-induced inhibition of NSCLC cells progression. Therefore, MIR31HG might serve as a promising prognostic marker and potential therapeutic target for NSCLC patients.

Long non‑coding RNA H19 regulates cell growth and metastasis via the miR‑22‑3p/Snail1 axis in gastric cancer

Gastric cancer (GC) is the fifth most prevalent type of malignancy and the third leading cause of cancer‑related mortality worldwide, with the prognosis of patients with late‑stage GC remaining at poor levels. Long non‑coding RNA (lncRNA) H19 (H19) is involved in the growth and metastasis of tumors, and it is upregulated under hypoxic conditions and in certain types of cancer; however, the underlying mechanisms of action of this lncRNA as regards the initiation and development of GC remain unknown. Thus, in the present study, we aimed to determine the role of lncRNA H19 in GC and to elucidate the underlying mechanisms. H19 was found to be upregulated in GC tissues and cells compared with the para‑cancerous tissues, and an elevated expression of H19 was associated with lymph node metastasis and TNM stage. Furthermore, the downregulation of H19 suppressed the proliferation, invasion, migration and epithelial‑mesenchymal transition of GC cells in vitro and suppressed tumor growth in vivo. H19 was also found to be able to bind with miR‑22‑3p, and H19‑induced cell growth and metastasis were shown to be reversed by the upregulation of miR‑22‑3p; the miR‑22‑3p level was found to inversely correlate with H19 expression in GC tissues. Furthermore, the overexpression of miR‑22‑3p notably suppressed the proliferation, migration and invasion of GC cells, and these effects were enhanced by the downregulation of Snail1. In addition, cell growth and metastasis induced by miR‑22‑3p downregulation were partially reversed by the knockdown of Snail1. Furthermore, a negative correlation was observed between the mRNA expression levels of miR‑22‑3p and Snail1 in GC tissues. On the whole, the findings of the present study revealed that H19 was upregulated in GC tissues, which promoted tumor growth and metastasis via the miR‑22‑3p/Snail1 signaling pathway. In summary, these findings provide novel insight into the potential regulatory roles of H19 in GC, and suggest that the H19/miR‑22‑3p/Snail1 axis may prove to be a promising therapeutic target for the treatment of patients with GC.

LINC01433/miR-2116-3p/MYC Feedback Loop Promotes Cell Proliferation, Migration, and the Epithelial-Mesenchymal Transition in Breast Cancer

Background: It is reported that long noncoding RNAs play an important role in human cancers, including breast cancer (BC). However, the effect of long intergenic non-protein coding RNA 1433 (LINC01433) on BC development remains elusive. Materials and Methods: The expression level of LINC01433 in BC cells and a normal breast epithelial cell (MCF-10A) was determined by quantitative real-time polymerase chain reaction (qRT-PCR). A series of functional assays was applied to measure the bio-function of LINC01433 in BC. Bioinformatics analysis and mechanistic assays were utilized to disclose the underlying mechanism involved in the LINC01433-mediated BC cellular process. Results: qRT-PCR revealed that LINC01433 was highly expressed in BC cells. In function, LINC01433 depletion suppressed BC cell proliferation, migration, and epithelial-mesenchymal transition, but induced cell apoptosis. Mechanically, chromatin immunoprecipitation and luciferase reporter assays suggested that LINC01433 was activated by its upstream transcription factor MYC proto-oncogene (MYC). The interaction between LINC01433 and miR-2116-3p was verified in BC. Additionally, MYC was validated as a target gene of miR-2116-3p. Rescue assays demonstrated that LINC01433 promoted BC cellular process via regulating miR-2116-3p/MYC axis. Conclusion: Our findings revealed a novel positive feedback loop (LINC01433/miR-2116-3p/MYC) in BC progression and discovered the novel functional genes in this BC cellular process.

Upregulation of the long noncoding RNA ADPGK-AS1 promotes carcinogenesis and predicts poor prognosis in gastric cancer

BACKGROUND

Numerous previous studies have revealed that many long non-coding RNAs (lncRNAs) are upregulated in gastric cancer (GC) and are associated with tumor onset and progression in GC. ADPGK-AS1, a novel lncRNA, has been discovered as an oncogenic lncRNA in pancreatic cancer while its function in GC remains unclear.

MATERIALS AND METHODS

The expression of ADPGK-AS1 and miR-3196 was determined by RT-qPCR. The expression of KDM1B was assessed by RT-qPCR and WB. The association between ADPGK-AS1 and overall survival of GC patients was explored using Kaplan-Meier curves. The function of ADPGK-AS1 in GC was examined through CCK-8, EdU, transwell as well as flow cytometry analysis. The interaction of miR-3196 and ADPGK-AS1 or KDM1B was confirmed by RIP, RNA pull down and luciferase reporter assay.Materials and Methods RESULTS: ADPGK-AS1 was increased in GC tissues and cell lines. GC patients with an increased expression of ADPGK-AS1 had a poor prognosis compared to those with a reduced expression. ADPGK-AS1 knockdown led to inhibition of GC cell proliferation and migration. The suppressive effect of ADPGK-AS1 silence on GC progression was abolished by KDM1B upregulation.Results CONCLUSIONS: We unveiled that ADPGK-AS1 could promote GC progression via sponging miR-3196 and therefore upregulating KDM1B, providing a novel prognostic biomarker and therapeutic target for GC patients.

CONCLUSIONS

SP1-induced lncRNA TINCR overexpression contributes to colorectal cancer progression by sponging miR-7-5p

Mounting evidences have indicated that long noncoding RNAs (lncRNAs) play pivotal roles in human diseases, especially in cancers. Recently, TINCR was proposed to be involved in tumor progression. However, its role in colorectal cancer (CRC) remains elusive. In our study, we found that SP1-induced TINCR was significantly upregulated in CRC tissues and cell lines. Moreover, cox multivariate survival analysis revealed that high TINCR was an independent predictor of poor overall survival (OS). Functionally, knockdown of TINCR obviously suppressed CRC cells proliferation, migration and invasion in vitro, and inhibited CRC cells growth and metastasis in vivo. Mechanistically, we identified TINCR could act as a miR-7-5p sponge using RNA pull down, luciferase reporter and RIP assays. Furthermore, we showed that TINCR might promote CRC progression via miR-7-5p-mediated PI3K/Akt/mTOR signaling pathway. Lastly, we revealed that plasma TINCR expression was upregulated in CRC when compared to healthy controls and could be a promising diagnostic biomarker for CRC. Based on above results, our data indicated that TINCR might serve as a potential diagnostic and prognostic biomarker for CRC.

Construction of lncRNA-mediated ceRNA network to reveal clinically relevant lncRNA biomarkers in glioblastomas

Cross-talk between competing endogenous RNAs (ceRNAs) play key roles in tumor development. In this study, we performed exon-level expression profiling on 26 glioblastomas (GBMs) and 6 controls to identify long non-coding RNAs (lncRNAs) of GBM initiation and progression using lncRNA-mediated ceRNA network (LMCN). The mRNA and lncRNA expression data, as well as miRNA-target interactions were firstly collected. Then, we used hypergeometric test to detect the lncRNA-mRNA interactions, followed by the construction of LMCN based on Pearson correlation coefficient. With the goal of investigation of the network organization, degree distribution of LMCN was performed. Next, the synergistic, competing lncRNA modules were identified using jActiveModule plug-in of Cytoscape. Moreover, we implemented the pathway analysis for its mRNAs in the module to explore the functions of significant lncRNAs. Using the criteria of degrees >50, 8 hub genes were identified, including EPB41L4A-AS1, ZRANB2-AS2, XIST, HOTAIR, TRAF3IP2-AS1, TPT1-AS1, PVT1 and DLG1-AS1. Furthermore, 1 synergistic, competitive module was identified. In this module, lncRNAs XIST and PVT1 were also the hubs in the synergistic, competing lncRNA module. Functional annotation demonstrated that 5 pathways were identified, including cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and mTOR signaling pathway. We have successfully identified several hubs (such as XIST and PVT1) and significant pathways (for instance, cytokine-cytokine receptor interaction, and neuroactive ligand-receptor interactions) for GBM via establishing the LMCN. These findings might offer potential biomarkers to early diagnose, and predict GBM prognosis in the future.

Novel long non-coding RNA LINC02532 promotes gastric cancer cell proliferation, migration, and invasion in vitro

BACKGROUND

Long non-coding RNAs (lncRNAs) are a kind of single-stranded RNA of more than 200 nucleotides in length and have no protein-coding function. Amounting studies have indicated that lncRNAs could play a vital role in the initiation and development of cancers, including gastric cancer (GC). Considering the crucial functions of lncRNAs, the identification and exploration of novel lncRNAs in GC is necessary.

AIM

To explore the role of novel lncRNA LINC02532 in GC.

METHODS

The upregulated LINC02532 was identified by processing the GC RNA-Seq data from The Cancer Genome Atlas. The qRT-PCR assay was performed to confirm the expression levels in GC cell lines and tissues. Cell proliferation, migration, and invasion were evaluated by the cell counting kit-8, colony formation, wound healing, and Transwell assays. The miRNAs downregulated in GC and sponged by LINC02532 were identified from and predicted by the data from the Firehose and RNA22 software programs, respectively. The miRNA downstream target genes were obtained from the TargetScan, miRDB, and DIANA online tools. Gene functional enrichment analysis was carried out using the Database for Annotation, Visualization, and Integrated Discovery software in the categories of cellular components, biological processes, molecular functions, and KEGG pathways.

RESULTS

The qRT-PCR assay demonstrated that the LINC02532 expression level was significantly upregulated in the GC cell lines and 52 paired tissues. Kaplan-Meier survival analysis based on The Cancer Genome Atlas data showed that patients with higher LINC02532 expression had poorer prognosis than those with lower LINC02532 expression. The correlation analysis between expression and clinicopathological features revealed that high expression of LINC02532 was associated with a high TNM stage (P = 0.008) and poor differentiation grade (P = 0.023). Functional experiments showed that LINC02532 promoted GC cell proliferation, migration, and invasion. According to the bioinformatics analysis, LINC02532 may act as a ceRNA by sponging downregulated miR-129-5p and miR-490-5p. Target genes of the two miRNAs were selected for further functional enrichment analysis. Importantly, KEGG pathway analysis showed that the genes were mainly involved in transcriptional misregulation in cancer, cell cycle, and TGF-beta, mTOR, and p53 signaling pathways.

CONCLUSION

The present study suggested that LINC02532 acted as an oncogene in GC and may be a promising target for therapy and prognosis management of GC.

Long noncoding RNA LINC01234 promotes serine hydroxymethyltransferase 2 expression and proliferation by competitively binding miR-642a-5p in colon cancer

Long noncoding RNAs (lncRNAs) have been indicated as important regulators in various human cancers. However, the overall biological roles and clinical significance of most lncRNAs in colon carcinogenesis are not fully understood. Hence, we investigated the clinical significance, biological function and mechanism of LINC01234 in colon cancer. First, we analyzed LINC01234 alterations in colon cancer tissues and corresponding paracancerous tissues through the analysis of sequencing data obtained from The Cancer Genome Atlas and colon cancer patients. Next, we evaluated the effect of LINC01234 on colon cancer cell proliferation and its regulatory mechanism of serine hydroxymethyltransferase 2 (SHMT2) by acting as a competing endogenous RNA (ceRNA). We found that LINC01234 expression was significantly upregulated in colon cancer tissues and was associated with a shorter survival time. Furthermore, the knockdown of LINC01234 induced proliferation arrest via suppressing serine/glycine metabolism. Mechanistic investigations have indicated that LINC01234 functions as a ceRNA for miR-642a-5p, thereby leading to the derepression of its endogenous target serine hydroxymethyltransferase 2 (SHMT2). LINC01234 is significantly overexpressed in colon cancer, and the LINC01234–miR642a-5p–SHMT2 axis plays a critical role in colon cancer proliferation. Our findings may provide a potential new target for colon cancer diagnosis and therapy.

Long noncoding RNA NEAT1-modulated miR-506 regulates gastric cancer development through targeting STAT3

Accumulating evidence has indicated that long noncoding RNA NEAT1 exerts critical roles in cancers. So far, the detailed biological role and mechanisms of NEAT1, which are responsible for human gastric cancer (GC), are still largely unknown. Here, we observed that NEAT1 and STAT3 expressions were significantly upregulated in human GC cells including BGC823, SGC-7901, AGS, MGC803, and MKN28 cells compared with normal gastric epithelial cells GES-1, while miR-506 was downregulated. We inhibited NEAT1 and observed that NEAT1 inhibition was able to repress the growth, migration, and invasion of GC cells. Conversely, overexpression of NEAT1 exhibited an increased ability of GC progression in BGC823 and SGC-7901 cells. Bioinformatics analysis, dual luciferase reporter assays, RIP assays, and RNA pull-down tests validated the negative binding correlation between NEAT1 and miR-506. In addition, it was found that miR-506 can modulate the expression of NEAT1 in vitro. STAT3 was predicted as a messenger RNA (mRNA) target of miR-506, and miR-506 mimics can suppress STAT3 mRNA expression. Subsequently, it was observed that downregulation of NEAT1 can restrain GC development by decreasing STAT3, which can be reversed by miR-506 inhibitors. Therefore, it was hypothesized in our study that NEAT1 can be recognized as a competing endogenous RNA to modulate STAT3 by sponging miR-506 in GC. In conclusion, we implied that NEAT1 can serve as an important biomarker in GC diagnosis and treatment.

DDN-AS1-miR-15a/16-TCF3 feedback loop regulates tumor progression in cervical cancer

Cervical cancer (CC) is known as one of the most common gynecological tumors. Long noncoding RNAs (lncRNAs) are a group of regulators that have been widely reported in human malignant tumors including CC. On the basis of the data of The Cancer Genome Atlas, lncRNA DDN and PRKAG1 antisense RNA 1 ( DDN-AS1) that is overexpressed in CC tissues predicted poor prognosis for patients with CC. Moreover, quantitative reverse transcription PCR analysis further identified the upregulation of DDN-AS1 in CC tissues and cell lines. Loss-of-function assays revealed that knockdown of DDN-AS1 suppressed CC progression by efficiently inhibiting cell proliferation, migration, and invasion. Mechanism investigations revealed that DDN-AS1 was upregulated by its upstream transcription activator transcription factor 3 ( TCF3). Moreover, DDN-AS1 increased the expression of  TCF3 by competitively binding miR-15a and miR-16. In conclusion, DDN-AS1-miR-15a/16-TCF3 feedback loop contributes to cell proliferation, migration, and invasion in CC.

Long noncoding RNA OIP5-AS1 causes cisplatin resistance in osteosarcoma through inducing the LPAATβ/PI3K/AKT/mTOR signaling pathway by sponging the miR-340-5p

The abnormal expression of long noncoding RNAs (lncRNAs) plays an important role in the regulation of human cancer progression and drug resistance. The lncRNA OPI5-AS1 is a crucial regulator in some cancers; however, its role in cisplatin resistance of osteosarcoma remains unclear. We found that OIP5-AS1 was significantly upregulated in cisplatin-resistant (CR) osteosarcoma cells MG63-CR and SaOS2-CR compared with the corresponding parental cells. OIP5-AS1 silencing suppressed cell growth in vitro and in vivo, and promoted apoptosis of MG63-CR and SaOS2-CR cells, indicating that knockdown of OIP5-AS1 significantly decreased cisplatin resistance in MG63-CR and SaOS2-CR cells. This conclusion was supported by the decreased expression of the drug resistance-related factors multidrug resistance-associated protein 1 (MRP1) and P-glycoprotein (P-gp) upon OIP5-AS1 silencing. In addition, OIP5-AS1 downregulation suppressed the PI3K/AKT/mTOR signaling pathway. Importantly, we demonstrated that OIP5-AS1 functions as a competing endogenous RNA of miR-340-5p and regulates the expression of lysophosphatidic acid acyltransferase (LPAATβ), which is a target of miR-340-5p. Moreover, downregulation of miR-340-5p partly reversed the inhibitory effect of OIP5-AS1 knockdown on the PI3K/AKT/mTOR pathway and therefore counteracted cisplatin resistance in MG63-CR and SaOS2-CR cells. In conclusion, OIP5-AS1 causes cisplatin resistance in osteosarcoma through inducing the LPAATβ/PI3K/AKT/mTOR signaling pathway by sponging the miR-340-5p. Our results contribute to a better understanding of the function and mechanism of OIP5-AS1 in osteosarcoma cisplatin resistance.

Long non-coding RNA 1308 promotes cell invasion by regulating the miR-124/ADAM 15 axis in non-small-cell lung cancer cells

Purpose

Emerging evidence suggests that many differentially expressed long non-coding RNAs (lncRNAs) are involved in tumorigenesis. However, the functional roles of these transcripts and the mechanisms responsible for their deregulation in non-small-cell lung cancer (NSCLC) remain elusive. Here, we identified a novel lncRNA (lncRNA 1308), which was significantly upregulated in NSCLC tissues and investigated its biological function and potential molecular mechanism.

Methods

Differences in the lncRNA expression profiles between NSCLC and tumor-adjacent normal tissues were assessed by lncRNA expression microarray analysis. The microRNA in vivo precipitation (miRIP) method was used to identify the targeting microRNAs (miRNAs) on lncRNA 1308, and luciferase reporter assays were performed. Loss-of-function studies were used to explore the effect of lncRNA 1308 on lung carcinogenesis in NSCLC cells.

Results

The novel lncRNA 1308 was upregulated in NSCLC tissues and cell lines. By using biotin-labeled lncRNA 1308 for miRIP in NSCLC cells and dual-luciferase reporter assays, the results suggested that miRNA-124 was associated with lncRNA 1308. Furthermore, the expression of a disintegrin and a metalloproteinase 15 (ADAM 15) was downregulated in NSCLC cells when silencing of lncRNA 1308, the target of oncogenic miR-124, inhibits NSCLC cell proliferation and invasion. Conversely, the expression of ADAM 15 was significantly increased, when inhibiting the expression of miR-124, and alleviated cell invasion inhibition.

Conclusion

The results suggested that lncRNA 1308 may function as a competing endogenous RNA (ceRNA) for miR-124 to regulate cell invasion through the miR-124/ADAM 15 signaling pathway, indicating that lncRNA 1308 plays an important role in the disease progression of NSCLC.

Prognostic Value of Long Noncoding RNAs in Patients with Gastrointestinal Cancer: A Systematic Review and Meta-Analysis

Gastrointestinal cancers (GICs) are a huge threat to human health, which mainly include esophageal, gastric, and colorectal cancers. The purpose of this study was to clarify the prognostic value of long noncoding RNAs (lncRNAs) in GICs. A total of 111 articles were included, and 13103 patients (3123 with esophageal cancer, 4972 with gastric cancer, and 5008 with colorectal cancer) were enrolled in this study. The pooled hazard ratio (HR) values and corresponding 95% confidence interval (95% CI) of overall survival (OS) related to different lncRNA expressions in esophageal, gastric, colorectal, and gastrointestinal cancer patients were 1.92 (1.70–2.16), 1.96 (1.77–2.16), 2.10 (1.87–2.36), and 2.00 (1.87–2.13), respectively. We have identified 74 lncRNAs which were associated closely with poor prognosis of GIC patients, including 58 significantly upregulated lncRNA expression and 16 significantly downregulated lncRNA expression. In addition, 47 of the included studies revealed relative mechanisms and 12 of them investigated the correlation between lncRNAs and microRNAs. Taken together, this meta-analysis supports that specific lncRNAs are significantly related to the prognosis of GIC patients and may serve as novel markers for predicting the prognosis of GIC patients. Furthermore, lncRNAs may have a promising contribution to lncRNA-based targeted therapy and clinical decision-making in the future.

Long noncoding RNA AC003092.1 promotes temozolomide chemosensitivity through miR-195/TFPI-2 signaling modulation in glioblastoma

Temozolomide (TMZ) and radiation therapy combination for glioblastoma (GB) patients has been considered as the most effective therapy after surgical procedure. However, the overall clinical prognosis remains unsatisfactory due to intrinsic or developing resistance to TMZ. Recently, increasing evidence suggested that long noncoding RNAs (lncRNAs) play a critical role in various biological processes of tumors, and have been implicated in resistance to various drugs. However, the role of lncRNAs in TMZ resistance is poorly understood. Here, we found that the expression of lncRNA AC003092.1 was markedly decreased in TMZ resistance (TR) of GB cells (U87TR and U251TR) compared with their parental cells (U87 and U251). In patients with glioma, low levels of lncRNA AC003092.1 were correlated with increased TMZ resistance, higher risk of relapse, and poor prognosis. Overexpression of lncRNA AC003092.1 enhances TMZ sensitivity, facilitates cell apoptosis, and inhibits cell proliferation in TMZ-resistant GB cells. In addition, we identified that lncRNA AC003092.1 regulates TMZ chemosensitivity through TFPI-2-mediated cell apoptosis in vitro and in vivo. Mechanistically, further investigation revealed that lncRNA AC003092.1 regulates TFPI-2 expression through miR-195 in GB. Taken together, these data suggest that lncRNA AC003092.1 could inhibit the function of miR-195 by acting as an endogenous CeRNA, leading to increased expression of TFPI-2; this promotes TMZ-induced apoptosis, thereby making GB cells more sensitive to TMZ. Our findings indicate that overexpression of lncRNA AC003092.1 may be a potential therapy to overcome TMZ resistance in GB patients.

Long non-coding RNA ARAP1-AS1 promotes the progression of bladder cancer by regulating miR-4735-3p/NOTCH2 axis

Accumulative reports have documented the critical functions of long non-coding RNAs (lncRNAs) in the progression of malignant tumors, including bladder cancer (BCa). LncRNA ARAP1-AS1 was chosen to be the object of this study due to it was significantly upregulated in the BCa samples of TCGA database. qRT-PCR further validated the dysregulation of ARAP1-AS1 in 88 pairs of BCa tissues and six BCa cells. Kaplan Meier analysis was utilized to analyze the prognostic value of ARAP1-AS1 for patients with BCa. To evaluate the oncogenic property of ARAP1-AS1 in bladder cancer, loss-of-function assays were conducted in two BCa cells in which ARAP1-AS1 was expressed highest. Mechanically, ARAP1-AS1 was enriched in the cytoplasm of BCa cells, suggesting that ARAP1-AS1 might act as a ceRNA to regulate gene expression and biological processes in bladder cancer. It was certified that ARAP1-AS1 can bind with miR-4735-3p in BCa cells. Moreover, functional assays supported the hypothesis that miR-4735-3p is a tumor suppressor in BCa. Additionally, NOTCH2 mRNA could be targeted by miR-4735-3p in BCa cells. The results of all mechanism experiments indicated that ARAP1-AS1 regulated miR-4735-3p/NOTCH2 axis in BCa by acting as a ceRNA. All our research findings may bring novel insights into the treatment of bladder cancer.

lncRNA MEG3 promotes hepatic insulin resistance by serving as a competing endogenous RNA of miR-214 to regulate ATF4 expression

MicroRNA (miR)-214 has been demonstrated to suppress gluconeogenesis by targeting activating transcription factor 4 (ATF4), which regulates gluconeogenesis by affecting the transcriptional activity of forkhead box protein O1 (FoxO1). Our previous study revealed that the upregulation of maternally expressed gene 3 (MEG3), a long noncoding RNA, enhanced hepatic insulin resistance via increased FoxO1 expression. The present study aimed to explore whether miR-214 and ATF4 were involved in the MEG3-mediated increase of FoxO1 expression. MEG3, miR-214 and ATF4 expression were examined by reverse transcription quantitative polymerase chain reaction and western blot analysis. The interaction among MEG3, miR-214 and ATF4 was analysed using the luciferase reporter assay. MEG3-targeting small interference RNAs were injected into high-fat diet (HFD)-fed mice to verify the role of MEG3 in hepatic insulin resistance in vivo. MEG-3 and ATF4 were demonstrated to be upregulated and miR-214 was indicated to be downregulated in the livers of HFD-fed and ob/ob mice. In mouse primary hepatocytes, palmitate time-dependently increased MEG3 and ATF4 but decreased miR-214 expression levels. Furthermore, MEG3 served as a competing endogenous RNA (ceRNA) for miR-214 to facilitate ATF4 expression, while miR-214 inhibition and ATF4 overexpression reversed the MEG3 knockdown-mediated decrease in the expression of FoxO1 and FoxO1-downstream targets phosphoenolpyruvate carboxykinase and glucose-6-phosphatase catalytic subunit. In HFD-fed mice, MEG3 knockdown substantially improved impaired glucose and insulin tolerance, while down-regulating HFD-induced ATF4 expression and upregulating HFD-suppressed miR-214 expression. In conclusion, MEG3 promoted hepatic insulin resistance by serving as a ceRNA of miR-214 to facilitate ATF4 expression. These data provide insight into the molecular mechanism of MEG3 involvement in the development of type 2 diabetes mellitus.

Increased expression of LINC01510 predicts poor prognosis and promotes malignant progression in human non-small cell lung cancer

Non-small cell lung cancer (NSCLC), the most prevalent type of lung cancer, is one of the most leading causes of cancer-related morbidity and mortality worldwide. Evidence is accumulating that long non-coding RNAs (lncRNAs) play vital regulatory roles in tumor development and progression. LINC01510, a novel tumor-related lncRNA, has been identified as an oncogene in colorectal cancer; however, its role in NSCLC remains poorly understood. This study aimed to characterize the biological role of LINC01510 in NSCLC and illuminate the molecular mechanisms. Here we found that LINC01510 was highly expressed in NSCLC tissues. Besides, Fisher's exact test showed that high expression of LINC01510 was associated with larger tumor size, advanced TNM stage and lymph node metastasis. Kaplan-Meier survival analysis showed that patients with high LINC01510 expression had a much lower overall survival rate. Gain- and loss-of-function approaches were employed to investigate the effects of LINC01510 on NSCLC cell phenotypes. Functional studies demonstrated that LINC01510 over-expression promoted NSCLC cell proliferation, cell cycle progression, migration and invasion, but shRNA-mediated LINC01510 depletion inhibited NSCLC cell proliferation, cell cycle progression, migration and invasion. Notably, LINC01510 ablation suppressed tumorigenicity of NSCLC cells in a murine xenograft model. Furthermore, mechanistic studies revealed that LINC01510 exerted its oncogenic functions in NSCLC through miR-339-5p-mediated regulation of CDK14. To sum up, our data indicate that increased expression of LINC01510 predicts poor prognosis and promotes tumorigenesis in NSCLC. Collectively, this study may provide a basis for LINC01510 as a candidate therapeutic target in NSCLC.

Microarray expression profile of long non-coding RNAs in human lung adenocarcinoma

BACKGROUND

Long non-coding RNAs (lncRNAs) participate in many biological dynamics and play significant roles in gene regulation. LncRNA expression is altered in many cancers; however, the expressions and functions of lncRNA genes in lung adenocarcinoma (LAD) remain unknown.

METHODS

LncRNA and messenger RNA (mRNA) expression in LAD without lymphatic metastasis versus paired adjacent non-tumor (ANT) lung tissues and LAD with versus without lymphatic metastasis were analyzed using Human LncRNA Arraystar V3.0. The expression levels of four downregulated and four upregulated lncRNAs were verified using quantitative real-time PCR in cells and tissue specimens.

RESULTS

In this study, 949 lncRNAs and 681 mRNAs had differential expression in LAD without lymphatic metastasis compared to ANT lung tissues, while 2740 lncRNAs and 1714 mRNAs were differentially expressed in LAD with lymphatic metastasis compared to LAD without lymphatic metastasis. The expression patterns of selected lncRNAs (LINC00113, AC005009.1, ARHGAP22-IT1, AC009411.1, SRGAP3-AS2, EGFEM1P, FAM66E, and HLA-F-AS1) were consistent with microarray data. Differentially expressed mRNA genes were enriched in crucial Gene Ontology terms and pathways.

CONCLUSION

Our results revealed differentially expressed lncRNAs in LAD, suggesting lncRNAs may be potential indicators for LAD diagnosis and therapy.

Integrated analysis of long noncoding RNA associated-competing endogenous RNA as prognostic biomarkers in clear cell renal carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant carcinomas and its molecular mechanisms remain unclear. Long noncoding RNA (lncRNA) could bind sites of miRNA which affect the expression of mRNA according to the competing endogenous (ceRNA) theory. The aim of the present study was to construct a ceRNA network and to identify key lncRNA to predict survival prognosis. We identified differentially expressed mRNA, lncRNA and miRNA between tumor tissues and normal tissues from The Cancer Genome Atlas database. Then, using bioinformatics tools, we explored the connection of 89 lncRNA, 10 miRNA and 22 mRNA, and we constructed the ceRNA network. Furthermore, we analyzed the functions and pathways of 22 differentially expressed mRNA. Then, univariate and multivariate Cox regression analyses of these 89 lncRNA and overall survival were explored. Nine lncRNA were finally screened out in the training group. The patients were divided into high‐risk and low‐risk groups according to the 9 lncRNA and low‐risk scores having better clinical overall survival (P < .01). Furthermore, the receiver operating characteristic curve demonstrates the predicted role of the 9 lncRNA. The 9‐lncRNA signature was successfully proved in the testing group and the entire group. Finally, multivariate Cox regression analysis and stratification analysis further proved that the 9‐lncRNA signature was an independent factor to predict survival. In summary, the present study provides a deeper understanding of the lncRNA‐related ceRNA network in ccRCC and suggests that the 9‐lncRNA signature could serve as an independent biomarker to predict survival in ccRCC patients.

Long non-coding RNA CCAL/miR-149/FOXM1 axis promotes metastasis in gastric cancer

Early evidence indicates that the long non-coding RNA CCAL plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of CCAL in gastric tumourigenesis and progression remain largely unknown. We observed that CCAL was upregulated in gastric cancer tissues and was associated with the tumour-node-metastasis stage. Functional experiments showed that CCAL promoted gastric cancer cell proliferation and metastasis in vitro and in vivo. Luciferase reporter assay indicated that CCAL directly bind to miR-149. Moreover, knockdown of CCAL significantly reduced the expression of FOXM1, a direct target of miR-149. We also showed that FOXM1 suppression by miR-149 could be partially rescued by CCAL overexpression. In addition, we identified a negative correlation between the mRNA expression of CCAL and miR-149 in gastric cancer tissues. Furthermore, we observed a negative correlation between the expression of miR-149 and FOXM1 and a positive correlation between CCAL and FOXM1 levels. These results demonstrated that the CCAL/miR-149/FOXM1 axis functions as a key regulator in gastric cancer metastasis and CCAL potentially represents a biomarker for diagnosis and potential target for therapy in the future.

SP1-induced lncRNA-ZFAS1 contributes to colorectal cancer progression via the miR-150-5p/VEGFA axis

Increasing long non-coding RNAs (lncRNAs) have been reported to play key roles in the development and progression of various malignancies. ZNFX1 antisense RNA1 (ZFAS1) has been reported to be aberrant expression and suggested as a tumor suppressor or oncogene in many cancers. However, the biological role and underlying molecular mechanism of ZFAS1, especially the miRNA sponge role of which in CRC remain largely unknown. We found that ZFAS1 expression was higher in CRC tissues, where it was associated with poor overall survival (OS), we also showed that ZFAS1 upregulation was induced by nuclear transcription factor SP1. Moreover, ZFAS1 and VEGFA are both targets of miR-150-5p, while ZFAS1 binds to miR-150-5p in an AGO2-dependent manner. Additionally, ZFAS1 upregulation markedly promoted as well as ZFAS1 knockdown significantly suppressed CRC cell proliferation, migration, invasion and angiogenesis, and the inhibitory effect caused by ZFAS1 knockdown could be reversed by antagomiR-150-5p. Lastly, we demonstrated that ZFAS1 knockdown inhibited EMT process and inactivated VEGFA/VEGFR2 and downstream Akt/mTOR signaling pathway in CRC. Our data demonstrated that SP1-induced ZFAS1 contributed to CRC progression by upregulating VEGFA via competitively binding to miR-150-5p, which acts as a tumor suppressor by targeting VEGFA in CRC.

EGR1-Mediated Transcription of lncRNA-HNF1A-AS1 Promotes Cell-Cycle Progression in Gastric Cancer

Long noncoding RNAs (lncRNA) are dysregulated in various human cancers and control tumor development and progression. However, the upstream mechanisms underlying their dysregulation remain unclear. Here, we demonstrate that the expression of hepatocyte nuclear factor 1 homeobox A antisense RNA 1 (HNF1A-AS1) is significantly upregulated in gastric cancer tissues. Overexpression of HNF1A-AS1 enhanced cell proliferation and promoted cell-cycle progression, whereas knockdown of HNF1A-AS1 elicited the opposite effects. Early growth response protein 1 (EGR1) directly bound the HNF1A-AS1 promoter region and activated its transcription. Overexpression of EGR1 enhanced cell proliferation and promoted cell-cycle promotion, similar to the function of HNF1A-AS1. HNF1A-AS1 functioned as competing endogenous RNA (ceRNA) by binding to miR-661, upregulating the expression of cell division cycle 34 (CDC34), which is a direct target of miR-661. EGR1 and HNF1A-AS1 enhanced the expression of cyclin-dependent kinase 2 (CDK2), CDK4, and cyclin E1 but inhibited the expression of p21 by promoting CDC34-mediated ubiquitination and degradation of p21. Taken together, these findings suggest that EGR1-activated HNF1A-AS1 regulates various pro- and antigrowth factors to promote the development of gastric cancer, implicating it as a possible target for therapeutic intervention in this disease.Significance: This study provides novel insights into mechanisms by which the noncoding RNA HNF1A-AS1 contributes to gastric cancer progression through modulation of the cell cycle. Cancer Res; 78(20); 5877-90. ©2018 AACR.

Prognostic value of long noncoding RNAs in gastric cancer: a meta-analysis

Background

In the last few years, accumulating evidence has indicated that numerous long noncoding RNAs (lncRNAs) are abnormally expressed in gastric cancer (GC) and are associated with the survival of GC patients. This study aimed to conduct a meta-analysis on 19 lncRNAs (AFAP1 antisense RNA 1 [AFAP1-AS1], CDKN2B antisense RNA 1 [ANRIL], cancer susceptibility 15 [CASC15], colon cancer associated transcript 2 [CCAT2], gastric adenocarcinoma associated, positive CD44 regulator, long intergenic noncoding RNA [GAPLINC], H19, imprinted maternally expressed transcript [H19], HOX transcript antisense RNA [HOTAIR], HOXA distal transcript antisense RNA [HOTTIP], long intergenic non-protein coding RNA 673 [LINC00673], metastasis-associated lung adenocarcinoma transcript 1 [MALAT1], maternally expressed 3 [MEG3], promoter of CDKN1A antisense DNA damage activated RNA [PANDAR], Pvt1 oncogene [PVT1], SOX2 overlapping transcript [Sox2ot], SPRY4 intronic transcript 1 [SPRY4-IT1], urothelial cancer associated 1 [UCA1], X inactive specific transcript [XIST], ZEB1 antisense RNA 1 [ZEB1-AS1] and ZNFX1 antisense RNA 1 [ZFAS1]) to systematically estimate their prognostic value in GC.

Methods

The qualified literature was systematically searched in PubMed, Web of Science, Embase and Cochrane Database of Systematic Reviews (up to March 16, 2018), and one meta-analysis relating to the relationship between lncRNA expression and overall survival (OS) of GC patients was performed. The only evaluation criterion of survival results was OS.

Results

A total of 6,095 GC patients and 19 lncRNAs from 51 articles were included in the present study. Among the listed 19 lncRNAs, 18 lncRNAs (other than SPRY4-IT1) showed a significantly prognostic value (P<0.05).

Conclusion

This meta-analysis suggested that the abnormally expressed lncRNAs (AFAP1-AS1, ANRIL, CASC15, CCAT2, GAPLINC, H19, HOTAIR, HOTTIP, LINC00673, MALAT1, MEG3, PANDAR, PVT1, Sox2ot, UCA1, XIST, ZEB1-AS1 and ZFAS1) were significantly associated with the survival of GC patients, among which AFAP1-AS1, CCAT2, LINC00673, PANDAR, PVT1, Sox2ot, ZEB1-AS1 and ZFAS1 were strong candidates in predicting the prognosis of GC patients.

NRAL mediates cisplatin resistance in hepatocellular carcinoma via miR-340-5p/Nrf2 axis

Recent studies have shown that long non-coding RNAs (lncRNAs) play a pivotal role in the pathogenesis and progression of hepatocellular carcinoma (HCC). However, the biological action and potential mechanism of liver cancer cell drug resistance have not been clearly clarified. In this study, lncRNAs were screened and differentially expressed in parental and cisplatin-resistant cell lines (HepG2 and HepG2/CDDP). A novel lncRNA, termed NRAL (Nrf2 regulation-associated lncRNA), was identified, and the initial results indicated that it was highly expressed in HepG2 cisplatin resistant cell lines compared to their parental counterparts. Functionally, NRAL depletion significantly enhanced CDDP-mediated cytotoxicity and apoptosis in two cisplatin-resistant HCC cell lines. Mechanistically, the results indicated that NRAL regulates Nrf2 expression through miR-340-5p serving as a competing endogenous RNA (ceRNA), thus influencing the CDDP-induced phenotype in HCC. Collectively, the present investigation suggest that the NRAL/miR-340-5p/Nrf2 axis mediates cisplatin resistance in HCC, which may provide novel targets for overcoming cisplatin resistance in hepatocellular carcinoma cells.

Long non-coding RNA UFC1 promotes gastric cancer progression by regulating miR-498/Lin28b

BACKGROUND

Long non-coding RNAs (lncRNAs) have emerged as important regulators of human cancers. However, the functional roles of lncRNAs and the mechanisms responsible for their aberrant expression in gastric cancer (GC) have not been well characterized.

METHODS

In this study, we examined the expression of lncRNA UFC1 in GC by qRT-PCR and explored its correlation with clinicopathological parameters. In vitro cell functional assays and in vivo animal studies were performed to determine the roles of UFC1 in GC progression.

RESULTS

UFC1 was elevated and predicted poorer prognosis in GC. UFC1 knockdown inhibited while UFC1 overexpression promoted GC cell proliferation, migration, and invasion. UFC1 bound to miR-498 to antagonize its tumor suppressive effect on Lin28b. Suppression of Lin28b by miR-498 could be rescued by UFC1 overexpression, whereas Lin28b overexpression partially rescued UFC1 knockdown-mediated inhibition of GC cell function. Lin28b expression was increased in GC and suggested a co-expression pattern with UFC1.

CONCLUSIONS

UFC1 has a promoting role in GC progression, at least in part, by acting as a miR-498 sponge and derepressing Lin28b expression, which would provide a novel biomarker for GC diagnosis and prognosis and offer a potential target for GC therapy.