Long intergenic non-protein coding RNA 00858 functions as a competing endogenous RNA for miR-422a to facilitate the cell growth in non-small cell lung cancer

Long noncoding RNA LINC00858 aggravates the progression of esophageal squamous cell carcinoma via regulating the miR-425-5p/ABL2 axis

Esophageal squamous cell carcinoma (ESCC) is one of the most fatal cancers with high morbidity and mortality, which severely affects people's lives. Long intergenic non-protein coding RNA 858 (LINC00858) was confirmed to promote the progression of colorectal cancer and lung cancer. However, the role of lncRNA LINC00858 is still unknown in ESCC. Herein, the main purpose of research was to explore LINC00858 function and its impact on ESCC cell biological behaviors. RT-qPCR was used to test the expression of LINC00858, miR-425-5p and ABL proto-oncogene 2 (ABL2) in ESCC cells. Functional experiments such as EdU assay, CCK-8 assay, transwell assay and Western blot assay were conducted to investigate the biological behaviors of ESCC cells. Luciferase reporter assay and RIP assay were implemented to determine the binding situation among RNAs. LINC00858 expression was abnormally high in ESCC cells and down-regulation of LINC00858 could restrain the proliferation, invasion, migration and EMT process of ESCC cells. Furthermore, miR-425-5p was proved to be sponged by LINC00858 and was down-regulated in ESCC cells. Besides, we discovered that miR-425-5p could target ABL2. Moreover, knockdown of ABL2 reversed the promoting function of miR-425-5p inhibitor on ESCC progression. LINC00858 aggravated ESCC progression via regulating the miR-425-5p/ABL2 axis.

Comprehensive Analysis to Identify LINC00511-hsa-miR-625-5p-SEMA6A Pathway Fuels Progression of Skin Cutaneous Melanoma

Objective

Skin cutaneous melanoma (SKCM) is a highly lethal malignancy that poses a significant threat to human health. Recent research has shown that competing endogenous RNA (ceRNA) regulatory networks play a critical role in the development and progression of various types of cancer, including SKCM. The objective of this study is to investigate the ceRNA regulatory network associated with the transmembrane protein semaphorin 6A (SEMA6A) and identify the underlying molecular mechanisms involved in SKCM.

Methods

Expression profiles of four RNAs, including pseudogenes, long non-coding RNAs, microRNAs, and mRNAs were obtained from The Cancer Genome Atlas database. The analysis was completed by bioinformatics methods, and the expression levels of the selected genes were verified by cell experiments.

Results

Bioinformatics analysis revealed that the LINC00511-hsa-miR-625-5p-SEMA6A ceRNA network was associated with SKCM prognosis. Furthermore, immune infiltration analysis indicated that the LINC00511-hsa-miR-625-5p-SEMA6A axis may have an impact on changes in the tumor immune microenvironment of SKCM.

Conclusion

The LINC00511-hsa-miR-625-5p-SEMA6A axis could be a promising therapeutic target and a prognostic biomarker for SKCM.

Decoding ceRNA regulatory network and autophagy-related genes in benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common disease among aging males. We obtained BPH transcriptional signatures by high-throughput RNA sequencing analysis. Accordingly, we determined the differentially expressed RNAs (DERNAs) between BPH tissues and normal prostate tissues. WebGestalt and R package (clusterprofiler) was used to enrichment analysis. Clinical correlations were analyzed using Spearman's coefficient. TargetScan, ENCORI, miRNet, and miRDB databases were used to predict targets' relationships in ceRNA networks. Immunofluorescence staining and qRT-PCR analyses were performed to validate the findings. Microarray analysis of the datasets showed 369 DElncRNAs, 122 DEpseudogenes, 6 DEmiRNAs and 1358 DEmRNAs. DEmRNAs were particularly enriched in the autophagy-related pathways. Following the screening of DEmRNAs and autophagy-related genes (ARGs), 50 DEARGs were selected. MCODE analysis on Cytoscape was performed for the 50 DEARGs, and 3 hub genes (ATF4, XBP1, and PPP1R15A) were obtained. Spearman's correlation analysis showed that the mRNA expression of XBP1 correlated positively with age, total score, and storage score, but negatively with the maximum flow rate. Subsequently, the pseudogene/lncRNA- hsa-miR-222-3p-XBP1 pathway was identified. Our findings elucidate that the pseudogene/lncRNA-hsa-miR-222-3p-XBP1 pathway may play a regulatory role in the occurrence of BPH through autophagy.

LINC00858 stabilizes RAN expression and promotes metastasis of gastric cancer

Metastasis constitutes one of the major causes of tumor-related death in gastric cancer (GC), and understanding key events in the initiation of this phenotypic switch may provide therapeutic opportunities. Long noncoding RNAs (lncRNAs) are emerging as molecules that play vital roles in tumorigenesis and metastasis. In this study, we aimed to identify metastasis-related lncRNAs in the context of GC. The lncRNAs overexpressed in tumor tissues and positively associated with overall survival were screened out using the TCGA database. qPCR assays in clinical samples showed that LINC00858 was significantly upregulated in GC tissues compared with normal counterparts. Functional analysis suggested that LINC00858 depletion attenuated the migration, and invasion of cancer cells in vitro and suppressed the metastasis of xenografted tumors in vivo. Mechanistically, LINC00858 could interact with the metastasis-associated RAN and stabilize its protein expression by decreasing posttranslational ubiquitination. The transcription factor YY1 could bind to the promoter of LINC00858 to upregulate its expression in GC cells. Moreover, overexpression of YY1 and RAN was positively associated with upregulation of LINC00858 in GC tissues. Our results suggest that LINC00858 might play a role in GC metastasis, and be a diagnostic biomarker and potential therapeutic target.

Remodelling of the tumour microenvironment by the kallikrein-related peptidases

Kallikrein-related peptidases (KLKs) are critical regulators of the tumour microenvironment. KLKs are proteolytic enzymes regulating multiple functions of bioactive molecules including hormones and growth factors, membrane receptors and the extracellular matrix architecture involved in cancer progression and metastasis. Perturbations of the proteolytic cascade generated by these peptidases, and their downstream signalling actions, underlie tumour emergence or blockade of tumour growth. Recent studies have also revealed their role in tumour immune suppression and resistance to cancer therapy. Here, we present an overview of the complex biology of the KLK family and its context-dependent nature in cancer, and discuss the different therapeutic strategies available to potentially target these proteases.

Long Non-Coding RNA THOR Depletion Inhibits Human Non-Small Cell Lung Cancer Cell Growth

Long non-coding RNA (LncRNA) THOR (Lnc-THOR) is expressed in testis and multiple human malignancies. Lnc-THOR association with IGF2BP1 (IGF2 mRNA-binding protein 1) is essential for stabilization and transcription of IGF2BP1 targeted mRNAs. We tested its expression and potential functions in non-small cell lung cancer (NSCLC). In primary NSCLC cells and established cell lines, Lnc-THOR shRNA or CRISPR/Cas9-mediated knockout (KO) downregulated IGF2BP1 target mRNAs (IGF2, Gli1, Myc and SOX9), inhibiting cell viability, growth, proliferation, migration and invasion. Significant apoptosis activation was detected in Lnc-THOR-silenced/-KO NSCLC cells. Conversely, ectopic overexpression of Lnc-THOR upregulated IGF2BP1 mRNA targets and enhanced NSCLC cell proliferation, migration and invasion. RNA-immunoprecipitation and RNA pull-down assay results confirmed the direct binding between Lnc-THOR and IGF2BP1 protein in NSCLC cells. Lnc-THOR silencing and overexpression were ineffective in IGF2BP1-KO NSCLC cells. Forced IGF2BP1 overexpression failed to rescue Lnc-THOR-KO NSCLC cells. In vivo, intratumoral injection of Lnc-THOR shRNA adeno-associated virus potently inhibited A549 xenograft tumor growth in nude mice. At last we show that Lnc-THOR is overexpressed in multiple NSCLC tissues and established/primary NSCLC cells. Collectively, these results highlighted the ability of Lnc-THOR in promoting NSCLC cell growth by associating with IGF2BP1, suggesting that Lnc-THOR represents a promising therapeutic target of NSCLC.

Risk Scores Based on Six Survival-Related RNAs in a Competing Endogenous Network Composed of Differentially Expressed RNAs Between Clear Cell Renal Cell Carcinoma Patients Carrying Wild-Type or Mutant Von Hippel-Lindau Serve Well to Predict Malignancy and Prognosis

Clear cell renal cell carcinoma (ccRCC) carrying wild-type Von Hippel–Lindau (VHL) tumor suppressor are more invasive and of high morbidity. Concurrently, competing endogenous RNA (ceRNA) network has been suggested to play an important role in ccRCC malignancy. In order to understand why the patients carrying wild-type VHL gene have high degrees of invasion and morbidity, we applied bioinformatics approaches to identify 861 differentially expressed RNAs (DE-RNAs) between patients carrying wild-type and patients carrying mutant VHL from The Cancer Genome Atlas (TCGA) database, established a ceRNA network including 122 RNAs, and elected six survival-related DE-RNAs including Linc00942, Linc00858, RP13_392I16.1, hsa-miR-182-5p, hsa-miR-183-5p, and PAX3. Examining clinical samples from our hospital revealed that patients carrying wild-type VHL had significantly higher levels of all six RNAs than those carrying mutant VHL. Patients carrying wild-type VHL had significantly higher risk scores, which were calculated based on expression levels of all six RNAs, than those carrying mutant VHL. Patients with higher risk scores had significantly shorter survival times than those with lower risk scores. Therefore, the risk scores serve well to predict malignancy and prognosis.

The tumorigenic function of LINC00858 in cancer

Long non-coding RNA (lncRNA) plays an important regulatory role in the occurrence and development of human cancer. LINC00858 is a newly discovered lncRNA with a length of 2685 nucleotides. Existing studies have shown that LINC00858 has abnormally high expression levels in malignant tumors such as colorectal cancer, gastric cancer, hepatocellular carcinoma, lung cancer, non-small cell lung cancer, ovarian cancer, osteosarcoma, retinoblastoma, Wilms tumor, bladder cancer, and cervical cancer. By regulating a variety of microRNAs, LINC00858 can affect tumor cell proliferation, invasion, metastasis, and apoptosis. Related research also found that LINC00858 is related to nuclear transcription factor/protein kinase and gene methylation. The aberrant expression of LINC00858 is related to the prognosis and clinicopathological characteristics of a variety of tumors. Overexpressed LINC00858 is closely related to the clinical stage, lymph node metastasis, and distant metastasis of cancer, including colorectal cancer, gastric cancer, non-small cell lung cancer, ovarian cancer, and Wilms tumor. Also, it is summarized that LINC00858 can regulate MAPK and TGF-β signaling pathways. This review shows that LINC00858 as an important oncogene can promote tumorigenesis and cancer development.

LncRNA RP11-465B22.8 triggers esophageal cancer progression by targeting miR-765/KLK4 axis

LncRNAs play an important role in tumorigenesis and progression; however, the function and mechanisms of lncRNAs in esophageal cancer (EC) remain largely unclear. In this study, we screened the differentially expressed lncRNAs in EC by using RNA-seq and one of the most upregulated lncRNAs, lncRNA RP11-465B22.8, was further characterized. LncRNA RP11-465B22.8 was upregulated in EC tissues and high lncRNA RP11-465B22.8 expression was associated with poor survival of EC patients. Ectopic expression of lncRNA RP11-465B22.8 enhanced the proliferation, migration, and invasion of EC cells, whereas knockdown of lncRNA RP11-465B22.8 led to the opposite effects. Mechanistically, lncRNA RP11-465B22.8 sponged miR-765 to increase the expression of KLK4. Moreover, LncRNA RP11-465B22.8 could be delivered from EC cells to macrophages via exosomes and subsequently induced M2 macrophage-induced cell migration and invasion. Our findings revealed a novel lncRNA RP11-465B22.8/miR-765/KLK4 pathway in EC and indicated that lncRNA RP11-465B22.8 might be a potential target for EC therapy.

LncRNA LINC00858 enhances cervical cancer cell growth through miR-3064-5p/ VMA21 axis

BACKGROUND

Cervical cancer (CC) is the most common form of gynecological malignancy. Long intergenic non-protein coding RNA 858 (LINC00858) has been identified to participate in multiple cancers. However, the role and mechanism of LINC00858 in CC cells are still elusive.

AIM

The aim of this study is to explore the biological functions and mechanisms of LINC00858 in CC cells.

METHODS

RT-qPCR analysis was used to examine the expression of LINC00858 in CC cells. EdU and colony formation assay were utilized to assess cell proliferation. TUNEL assay and flow cytometry assay were conducted to assess cell apoptosis. The mechanism regarding LINC00858 was certified through RNA pull down, RIP and luciferase reporter assays.

RESULTS

The up-regulated LINC00858 was detected in CC cells. Reduction of LINC00858 effectively subdued CC cells proliferation and stimulated cell apoptosis. LINC00858 was determined to bind with miR-3064-5p and up-regulate VMA21 in CC cells. In rescue assays, miR-3064-5p down-regulation and VMA21 up-regulation were able to counteract the effect caused by LINC00858 decrease on CC cell proliferation and apoptosis.

CONCLUSION

LINC00858 enhances cell proliferation, while restraining cell apoptosis in CC through targeting miR-3064-5p/VMA21 axis, implying that LINC00858 may serve as a promising therapeutic target for CC.

Long non-coding RNA CRNDE regulates the growth and migration of prostate cancer cells by targeting microRNA-146a-5p

The function of lncRNA CRNDE and its role in prostate cancer (PC) remains unclear. The aim of this study was to determine the expression level of lncRNA CRNDE in PC tissues and to elucidate its role in PC. The expression levels of lncRNA CRNDE were measured by quantitative reverse transcription polymerase chain reaction. The role of lncRNA CRNDE in PC cells was studied using loss-of-function assays in vitro. Cell proliferation, migration, invasion, and apoptosis were assessed via Cell Counting Kit-8, colony formation, flow cytometry, wound healing, and transwell chamber assays. A luciferase reporter assay was used to characterize the interaction between lncRNA CRNDE and miR-146a-5p. In PC tissues, the expression level of lncRNA CRNDE was upregulated. Moreover, knockdown of lncRNA CRNDE suppressed PC cell proliferation and migration and induced apoptosis in vitro. miR-146a-5p was verified as a direct target of lncRNA CRNDE. Moreover, the inhibition of miR-146a-5p partially counteracted the effects of lncRNA CRNDE on PC cell proliferation, migration, and invasion. In conclusion, lncRNA CRNDE may serve as a cancer promoter in PC by targeting miR-146a-5p. Therefore, lncRNA CRNDE could be a promising target for the clinical treatment of PC.

Competing endogenous RNAs in lung cancer

Competing endogenous RNAs (ceRNAs) containing microRNA response elements can competitively interact with microRNA via miRNA response elements, which can combine non-coding RNAs with protein-coding RNAs through complex ceRNA networks. CeRNAs include non-coding RNAs (long non-coding RNAs, circular RNAs, and transcribed pseudogenes) and protein-coding RNAs (mRNAs). Molecular interactions in ceRNA networks can coordinate many biological processes; however, they may also lead to ceRNA network imbalance and thus contribute to cancer occurrence when disturbed. Recent studies indicate that many dysregulated RNAs derived from lung cancer may function as ceRNAs to regulate multitudinous biological functions for lung cancer, including tumor cell proliferation, apoptosis, growth, invasion, migration, and metastasis. This study therefore reviewed the research progress in the field of non-coding and protein-coding RNAs as ceRNAs in lung cancer, and highlighted validated ceRNAs involved in biological lung cancer functions. Furthermore, the roles of ceRNAs as novel prognostic and diagnostic biomarkers were also discussed. Interpreting the involvement of ceRNAs networks in lung cancer will provide new insight into cancer pathogenesis and treatment strategies.

NORAD regulates epithelial‑mesenchymal transition of non‑small cell lung cancer cells via miR‑422a

The poor prognosis of non‑small cell lung cancer (NSCLC) is related to epithelial‑mesenchymal transition (EMT). Recent studies demonstrated that non‑coding RNA activated by DNA damage (NORAD) displays a carcinogenic effect and targets microRNA (miR)‑422a, which may be involved in tumor cell migration and invasion. The aim of the present study was to investigate the effect of NORAD on NSCLC cell EMT and the underlying mechanism. Reverse transcription‑quantitative PCR and western blotting were performed to detect the expression levels of long non‑coding RNAs, miRNAs and mRNAs. Cell viability, migration and invasion were detected by conducting Cell Counting Kit‑8, wound healing and Transwell assays, respectively. The target of NORAD was predicted using starBase and further confirmed by conducting a dual‑luciferase reporter assay. The results indicated that NORAD expression was significantly increased in lung cancer tissues and cells compared with adjacent healthy tissues and cells. Compared with the control groups, NORAD overexpression promoted SK‑MES‑1 cell viability, migration and invasion, whereas NORAD knockdown resulted in the opposite effects in A549 cells. Moreover, miR‑422a, which was predicted to be a target of NORAD, displayed lower expression levels in lung cancer tissues compared with adjacent healthy tissues. In addition, miR‑422a overexpression partially reversed NORAD overexpression‑induced increases in SK‑MES‑1 cell viability, migration, invasion and EMT. In addition, miR‑422a knockdown partially reversed the effects of NORAD knockdown. The present study suggested that NORAD regulated lung cancer cell EMT by regulating the expression of miR‑422a, providing a potential therapeutic target for the intervention of the development of NSCLC.

Targeting LncRNA EPIC1 to inhibit human colon cancer cell progression

Long non-coding RNA EPIC1 (Lnc-EPIC1) binds MYC protein, which is essential for MYC function and expression of MYC target genes. The current study tested its expression and potential functions in human colon cancer cells. We show that Lnc-EPIC1 expression is elevated in human colon cancer tissues and primary human colon cancer cells. Whereas its expression is relatively low in normal colon tissues and colon epithelial cells. In the primary human colon cancer cells, Lnc-EPIC1 siRNA largely inhibited cancer cell growth, proliferation, migration and invasion. Further, Lnc-EPIC1 silencing induced significant apoptosis activation in colon cancer cells. Conversely, ectopic overexpression of Lnc-EPIC1 augmented colon cancer cell growth, proliferation, migration and invasion. RNA-immunoprecipitation and RNA pull-down results confirmed that Lnc-EPIC1 directly binds MYC protein in colon cancer cells. MYC target proteins, including cyclin A, cyclin D and CDK9, were downregulated with Lnc-EPIC1 silencing, but upregulated after Lnc-EPIC1 overexpression in colon cancer cells. Further Lnc-EPIC1 silencing or overexpression failed to alter functions of MYC-knockout colon cancer cells. Collectively, overexpressed Lnc-EPIC1 is important for the progression of human colon cancer cells.

A Systematic Analysis of Dysregulated Long Non-Coding RNAs/microRNAs/mRNAs in Lung Squamous Cell Carcinoma

BACKGROUND

Lung squamous cell carcinoma (LUSC) accounts up for approximately 30% of all lung cancers with a high mortality. The study was aimed at finding genes critical in the diagnosis and prognosis of LUSC.

MATERIALS AND METHODS

The differentially expressed (DE) genes (DEGs) and DE lncRNAs (DELs) from 501 LUSC and 49 normal lung tissues, and DE miRNAs (DEMs) from 478 LUSC and 45 normal lung tissues were respectively obtained via the TCGA database. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and co-expression network analyses were performed. Survival analysis and receiver operating characteristic curve of hub mRNAs were also analyzed. Competitive endogenous RNA networks of lncRNAs, miRNAs and mRNAs were constructed.

RESULTS

A total of 5747 DEGs, 378 DEMs and 3141 DELs in LUSC were identified in LUSC. The DEGs including AUARK, CDK1, KIF11 and EXO1 were proven to be significant metastatic indicators in LUSC, and 2 DEGs were significantly associated with the survival in LUSC patients. Some genes might have connections with many other gene nodes through a co-expression network. Four lncRNAs, 2 mRNAs and 2 miRNAs were identified as the candidates for the competitive miRNA-mRNA-lncRNA network and might serve as prognostic markers in LUSC.

CONCLUSIONS

We identified the differentially expressed lncRNAs, miRNAs and mRNAs in LUSC, providing further insights into the molecular mechanism of LUSC tumorigenesis and the potential prognostic biomarkers or therapeutic targets for LUSC.

Upregulation of TRIAP1 by the lncRNA MFI2-AS1/miR-125a-5p Axis Promotes Thyroid Cancer Tumorigenesis

Background

Thyroid cancer is a very common endocrine cancer worldwide. How long noncoding RNA (lncRNA) regulates thyroid cancer is elusive. LncRNA MFI2-AS1 has been demonstrated to initiate colorectal cancer. Nevertheless, the role of MFI2-AS1 in thyroid cancer remains unknown. This study aims to determine the roles of MFI2-AS1 in thyroid cancer.

Methods

qRT-PCR was used to determine the expression of MFI2-AS1 in thyroid cancer tissues and cells. Proliferation was determined by using CCK8 and colony formation assays. Transwell assay was utilized to analyze migration and invasion. Luciferase reporter assay was performed to confirm the interaction between MFI2-AS1 and miR-125a-5p.

Results

MFI2-AS1 was shown to be highly expressed in thyroid cancer tissues and predicted poor prognosis. Knockdown of MFI2-AS1 inhibited proliferation, colony formation, migration and invasion of thyroid cancer cells in vitro. Bioinformatics screening identified MFI2-AS1 as the sponge for miR-125a-5p. And miR-125a-5p was further confirmed to target TRIAP1 directly. Our data further demonstrated that MFI2-AS1 promoted TRIAP1 expression via repressing miR-125a-5p. Finally, TRIAP1 was found to be upregulated in thyroid cancer tissues and its restoration reversed the effects of MFI2-AS1 depletion.

Conclusion

Our results elucidated a novel mechanism that MFI2-AS1 promotes thyroid cancer progression via the miR-125a-5p/TRIAP1 pathway.

LINC00858 knockdown inhibits gastric cancer cell growth and induces apoptosis through reducing WNK2 promoter methylation

BACKGROUND

Emerging evidence indicates a regulatory role of long non-coding RNAs (lncRNAs) in the development of gastric cancer (GC), but the mechanisms underlying their function have remained largely unknown. Recent microarray-based expression profiling has led to the identification of a novel differentially expressed lncRNA, LINC00858, in GC. Subsequently, LINC00858 was found to be highly expressed in GC tissues and cells. This study was designed to clarify the functional role of LINC00858 in GC, including its effect on methylation of the WNK2 gene promoter and its downstream MAPK signaling pathway.

METHODS

After exogenous over-expression and knockdown of LINC00858 and the addition of a MAPK pathway inhibitor in GC cells, we explored the effects of LINC00858 and the MAPK signaling pathway on GC cell behavior using various in vitro and in vivo assays.

RESULTS

LINC00858 was found to negatively regulate WNK2 expression by enhancing its promoter methylation and to activate the MAPK signaling pathway. Moreover, we found that knockdown of LINC00858 or inhibition of the MAPK signaling pathway resulted in decreased GC cell growth, migration and invasion, as well as decreased cell cycle progression, along with increased apoptosis and decreased tumorigenicity.

CONCLUSIONS

Together, these findings indicate that silencing of LINC00858 increases WNK2 expression and inhibits the MAPK signaling pathway, thereby inhibiting GC growth and development. Our data highlight LINC00858 as a potential target in GC therapy.

LINC00958 Accelerates Cell Proliferation and Migration in Non-Small Cell Lung Cancer Through JNK/c-JUN Signaling

Non-small cell lung cancer (NSCLC) denotes the most common type of lung cancers with high mortality globally. Long non-coding RNAs (lncRNAs) with differential expression have been indicated to be participants in the pathogenesis and development of cancer. However, the precise role of lncRNAs in NSCLC is still largely obscure. In this study, we explored a newly discovered intergenic lncRNA LINC00958 in NSCLC. First of all, the online databases suggested that LINC00958 was slightly expressed in human normal lung tissues but upregulated in LUSC tissues. Besides, the upregulation of LINC00958 in both lung adenocarcinoma (LUAD) and LUSC cell lines was easily found when compared with the normal BEAS-2B cells. In addition, we elucidated that knockdown of LINC00958 led to impaired proliferation, induced apoptosis, and hampered migration in LUAD cells. Moreover, a typical oncogenic pathway, JNK signaling, was verified to be involved in LINC00958-contributed LUAD development. Of note, we explained that LINC00958 exerted the tumor-promoting function in LUAD by enhancing the transactivation of p-c-JUN through activating JNK signaling. Meanwhile, we also revealed that LINC00958 was transcriptionally regulated by c-JUN. In addition, earlier findings were also suitable for LUSC cells. By and large, our work illustrated that LINC00958 facilitates tumorigenesis in NSCLC by activating the JNK/c-JUN signaling pathway, indicating a new road for diagnosis and treatment of both LUAD and LUSC.

Integrated analysis of lymphocyte infiltration-associated lncRNA for ovarian cancer via TCGA, GTEx and GEO datasets

Background

Abnormal expression of long non-coding RNAs (lncRNA) play a significant role in the incidence and progression of high-grade serous ovarian cancer (HGSOC), which is a leading cause of mortality among gynecologic malignant tumor patients. In this study, our aim is to identify lncRNA-associated competing endogenous RNA (ceRNA ) axes that could define more reliable prognostic parameters of HGSOC, and to investigate the lncRNAs’ potential mechanism of in lymphocyte infiltration.

Methods

The RNA-seq and miRNA expression profiles were downloaded from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database; while for obtaining the differentially expressed lncRNAs (DELs), miRNAs (DEMs), and genes (DEGs), we used edgeR, limma and DESeq2. After validating the RNA, miRNA and gene expressions, using integrated three RNA expression profiles (GSE18520, GSE27651, GSE54388) and miRNA profile (GSE47841) from the Gene Expression Omnibus (GEO) database, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analyses through ClusterProfiler. The prognostic value of these genes was determined with Kaplan–Meier survival analysis and Cox regression analysis. The ceRNA network was constructed using Cytoscape. The correlation between lncRNAs in ceRNA network and immune infiltrating cells was analyzed by using Tumor IMmune Estimation Resource (TIMER), and gene markers of tumor-infiltrating immune cells were identified using Spearman’s correlation after removing the influence of tumor purity.

Results

A total of 33 DELs (25 upregulated and eight downregulated), 134 DEMs (76 upregulated and 58 downregulated), and 1,612 DEGs (949 upregulated and 663 downregulated) were detected that could be positively correlated with overall survival (OS) of HGSOC. With the 1,612 analyzed genes, we constructed a ceRNA network, which indicated a pre-dominant involvement of the immune-related pathways. Furthermore, our data revealed that LINC00665 influenced the infiltration level of macrophages and dendritic cells (DCs). On the other hand, FTX and LINC00665, which may play their possible roles through the ceRNA axis, demonstrated a potential to inhibit Tregs and prevent T-cell exhaustion.

Conclusion

We defined several prognostic biomarkers for the incidence and progression of HGSOC and constructed a network for ceRNA axes; among which three were indicated to have a positive correlation with lymphocyte infiltration, namely: FTX-hsa-miR-150-5p-STK11, LINC00665-hsa-miR449b-5p-VAV3 and LINC00665-hsa-miR449b-5p-RRAGD.

Up-regulation of long noncoding RNA LINC00858 is associated with poor prognosis in gastric cancer

BACKGROUND

The present study aimed to investigated the expression pattern of long noncoding RNA LINC00858 (LINC00858) in gastric cancer (GC) patients and its feasibility as a new prognostic biomarker.

METHODS

We examined LINC00858 expression in GC tissues and matched normal tissues from 189 patients using a quantitative reverse transcription-polymerase chain reaction. The correlations of LINC00858 levels in GC patients with clinicopathologic features were analyzed using a chi-squared test. The influence of LINC00858 on the overall survival rate of GC patients was precisely calculated using Kaplan-Meier methods (log rank tests). Multivariate Cox regression assays were carried out for the identification of the independent risk factors for GC.

RESULTS

We observed that LINC00858 was distinctly up-regulated in GC tissues compared to adjacent non-tumor specimens (p < 0.01). Higher expression of LINC00858 in GC was found to be associated with TNM stage (p = 0.003) and lymphatic metastasis (p = 0.007). Using Kaplan-Meier assays, we found that patients with high expression levels of LINC00858 had a distinctly poor overall survival and disease-free survival compared to those with low expression levels of LINC00858 (p = 0.0102). Multivariate analyses confirmed that LINC00858 (p < 0.05) was an independent prognosis factor for GC patients.

CONCLUSIONS

The data obtained in our study indicate that LINC00858 may be used as a novel prognostic indicator in GC patients.

The circular RNA NT5E promotes non-small cell lung cancer cell growth via sponging microRNA-134

The current study tested expression and potential function of circular RNA ecto-5’-nucleotidase (circNT5E) in human non-small cell lung cancer (NSCLC). We show that circNT5E levels are significantly elevated in human NSCLC tissues and cells, correlating with downregulation of its potential targets, miR-134, miR-422a and miR-338. In A549 and primary NSCLC cells, circNT5E shRNA inhibited cancer cell growth, proliferation and migration, whiling inducing apoptosis activation. Conversely, ectopic circNT5E overexpression promoted A549 cell progression in vitro. miR-134 is the primary target of circNT5E in lung cancer cells. RNA-Pull down assay in A549 cells confirmed the direct association between biotinylated-miR-134 and circNT6E. miR-134 levels were significantly increased in circNT5E-silenced A549 cells, but reduced with circNT5E overexpression. Forced overexpression of miR-134 mimicked circNT5E shRNA-induced actions, inhibiting NSCLC cell growth and proliferation. In contrast, miR-134 inhibition largely attenuated circNT5E shRNA-induced anti-NSCLC cell activity. Importantly, circNT5E shRNA was ineffective in miR-134-overexpressed A549 cells. Collectively, circNT5E promotes human NSCLC cell progression possibly by sponging miR-134.

Long non‑coding RNA LINC00858 promotes TP53‑wild‑type colorectal cancer progression by regulating the microRNA‑25‑3p/SMAD7 axis

Long non-coding RNAs (lncRNAs) are involved in colorectal cancer (CRC) progression, however the mechanisms remain largely unknown. The present study aimed to reveal the role and possible molecular mechanisms of a new LNCRNA, LINC00858, in CRC. LINC00858 was increased in CRC tumor tissues, and patients with high LINC00858 expression had a shorter survival time. Knockdown of LINC00858 expression suppressed cell proliferation and induced G₀/G₁ cell cycle arrest and apoptosis in TP53-wild-type CRC cells. Subsequently, using Starbase v2.0 database, miR-25-3p was confirmed to interact with LINC00858 and was downregulated by LINC00858. Reduction of miR-25-3p expression with an inhibitor significantly attenuated the biological effects of LINC00858 knockdown in CRC cells. Furthermore, using TargetScan, SMAD7 was validated to interact with miR-25-3p and was downregulated by miR-25-3p. Lastly, the ectopic overexpression of SMAD7 rescued the suppressive effects of LINC00858 knockdown in CRC cells. Collectively, the results from the present study, to the best of our knowledge, firstly demonstrated a novel LINC00858/miR-25-3p/SMAD7 regulatory axis that promoted CRC progression, indicating LINC00858 as a promising therapeutic target for CRC.

LINC00858 promotes colorectal cancer by sponging miR-4766-5p to regulate PAK2

OBJECTIVES

LncRNAs (long noncoding RNAs) have been reported to critically regulate colorectal cancer (CRC). We prospectively investigated effects and mechanisms of lncRNA LINC00858 on regulation of CRC progression.

METHODS

Expression of LINC00858 and its target were analyzed by quantitative real-time polymerase chain reaction and in situ hybridization. MTT and bromodeoxyuridine/5-bromo-2'-deoxyuridine (BrdU) staining to assess cell proliferation ability. Flow cytometry, wound healing, and transwell assays were conducted to evaluate cell apoptosis, migration, and invasion, respectively. Interaction between LINC00858 and its target was confirmed by luciferase activity assay and RNA immunoprecipitation. Subcutaneous xenotransplanted tumor model was established and employed to detect tumorigenic functions of LINC00858, and further evaluated by qRT-PCR, western blot, immunohistochemistry, and hematoxylin and eosin staining.

RESULTS

With a predicted poor prognosis, LINC00858 was upregulated in CRC patients. LINC00858 knockdown suppressed cell proliferation, invasion, and migration abilities, meanwhile induced cell apoptosis. Moreover, LINC00858 could target and inhibit the miR-4766-5p expression, thus promoting CRC progression. miR-4766-5p further suppressed serine/threonine kinase PAK2. Interestingly, interference of LINC00858 suppressed tumorigenic ability of CRC in vivo by downregulating PAK2.

CONCLUSIONS

LINC00858 promoted CRC progression by sponging miR-4766 to upregulate PAK2, shedding lights on LINC00858 as a potential therapeutic target candidate in CRC treatment from bench to clinic.

Identification of lncRNA biomarkers in lung squamous cell carcinoma using comprehensive analysis of lncRNA mediated ceRNA network

Long non-coding RNAs (lncRNAs) act as a member of competing endogenous RNAs (ceRNAs) and plays a significant role in tumorigenesis. The aim of this study was to identify potential lncRNA biomarkers for predicting the prognosis of lung squamous cell carcinoma (LUSC) using a comprehensive analysis of lncRNA mediated ceRNA network. Differentially expressed RNAs datasets were obtained using edge R package in 502 LUSC tissues and 49 adjacent non-LUSC tissues from the Cancer Genome Atlas (TCGA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to identify functional enrichment implication of lncRNA related differentially expressed mRNAs. Survival analysis was used Kaplan-Meier curve method. Univariate and multivariate Cox regression analysis were performed to construct a predictive model with lncRNA biomarkers. A total of 2185 lncRNAs, 170 miRNAs and 2053 mRNAs were differentially expressed between LUSC tissues and adjacent non-LUSC tissues. The novel constructed ceRNA network incorporated 184 LUSC-specific lncRNAs, 18 miRNAs, and 49 mRNAs. About 11 of 184 differentially expressed lncRNAs and 1 of 18 differentially expressed miRNAs and 5 of 49 differentially expressed mRNAs were conspicuously related to overall survival (p < .05). Univariate and multivariate cox regression analysis showed that 6 lncRNAs were retrieved to construct a predictive model to predict the overall survival in LUSC patients. In conclusion, CeRNAs contributed to the progression of LUSC and a model with 6 lncRNAs might be potential biomarker for predicting the prognosis of LUSC.

Long non-coding RNA LINC00858 exerts a tumor-promoting role in colon cancer via HNF4α and WNK2 regulation

BACKGROUND

Long non-coding RNAs (lncRNAs) are known to be frequently dysregulated in many types of human cancer. As yet, however, their roles in colon carcinogenesis have not been fully elucidated. In the current study, we assessed whether lncRNA LINC00858 may be involved in the progression of colon cancer and, in addition, investigated its downstream targets.

METHODS

LINC00858 expression in patient-derived colon cancer tissues and in colon cancer cell lines was determined using RT-qPCR. Also, relationships between LINC00858 expression and various clinicopathological characteristics were analyzed. The subcellular localization of LINC00858 was determined using fluorescence in situ hybridization. Interactions between LINC00858 and its downstream targets were first predicted by bioinformatic analysis and, subsequently, confirmed by RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation and dual luciferase reporter assays. After in vitro upregulation of LINC00858 and/or silencing of WNK2 and hepatocyte nuclear factor 4α (HNF4α), the biological behavior of colon cancer cells was assessed using 5-ethynyl-2'-deoxyuridine (EdU) incorporation, Transwell invasion and tube formation assays. In vivo cancer growth was evaluated in nude mice.

RESULTS

We found that LINC00858 was highly expressed in primary colon cancer tissues and colon cancer cell lines, and was mainly located in the nucleus. High LINC00858 expression was found to correlate with a poor differentiation, advanced TNM stages and lymph node metastasis. Exogenous overexpression of LINC00858 promoted cell proliferation, invasion and migration of colon cancer cells, and facilitated angiogenesis and tumor growth. In addition, we found that LINC00858 can bind to and upregulate the nuclear transcription factor HNF4α, leading to WNK2 expression downregulation. This, in turn, resulted in the promotion of colon cancer cell growth.

CONCLUSIONS

From our data we conclude that LINC00858 acts as a tumor-promoting lncRNA in colon cancer by upregulating HNF4α and downregulating WNK2. Our results may provide novel targets for the treatment for colon cancer.

LINC00858 promotes retinoblastoma cell proliferation, migration and invasion by inhibiting miR-3182

The aim of the present study was to determine the role of long intergenic non-protein coding RNA 858 (LINC00858) in retinoblastoma (RB) and investigate the underlying molecular mechanisms. RB tissues and paracancerous tissues of 27 RB cases were obtained. RB cell lines (SO-RB50, Y79, HXO-RB44 and WERI-Rb1) and a normal retinal epithelial cell line (ARPE-19) were cultured for in vitro experiments. Batches of SO-RB50 and Y79 cells were assigned to groups transfected with small interfering RNA targeting LINC00858 (si-LINC00858 group), microRNA (miR)-3182 mimics or inhibitor, or the respective controls. A Cell Counting Kit-8 and Transwell assays were performed to assess the effect of the transfections on the proliferation, migration and invasion of SO-RB50 and Y79 cells. A luciferase reporter assay was performed using SO-RB50 cells to demonstrate the direct binding of LINC00858 and miR-3182. Reverse transcription-quantitative PCR was employed to detect LINC00858 and miR-3182 expression. Pearson correlation analysis was used to assess the correlation between the expression of LINC00858 and miR-3182. The results indicated that RB tissues and cells exhibited aberrantly elevated LINC00858 expression (P<0.05). Compared with those in the control-transfected group, SO-RB50 and Y79 cells of the si-LINC00858 group had a lower cell proliferation, as well as a lower number of migrated and invaded cells (all P<0.05). miR-3182 was proven to be a target gene of LINC00858, to be abnormally downregulated in RB tissues and cells (P<0.05) and to be negatively correlated with LINC00858 expression. Compared with those in the si-LINC00858 + inhibitor-negative control group, SO-RB50 and Y79 cells of the si-LINC00858 + miR-3182 inhibitor group exhibited a significantly higher relative proliferation, migration and invasion (all P<0.05). In conclusion, LINC00858 promoted RB cell proliferation, migration and invasion, at least partially by inhibiting miR-3182.

Competitive Endogenous RNA Network Construction and Comparison of Lung Squamous Cell Carcinoma in Smokers and Nonsmokers

Background

Lung squamous cell carcinoma (LUSC) is a subtype of highly malignant lung cancer with poor prognosis, for which smoking is the main risk factor. However, the underlying genetic and molecular mechanisms of smoking-related LUSC remain largely unknown.

Methods

We mined existing LUSC-related mRNA, miRNA, and lncRNA transcriptome data and corresponding clinical data from The Cancer Genome Atlas (TCGA) database and divided them into smoking and nonsmoking groups, followed by differential expression analysis. Functional enrichment analysis of the unique differentially expressed mRNAs of the two groups was performed using the DAVID database. Subsequently, the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network of LUSC in smoking and nonsmoking groups was constructed. Finally, survival analyses were performed to determine the effects of differentially expressed lncRNAs/mRNAs/miRNAs that were involved in the ceRNA network on overall survival and to discover the hub genes.

Results

A total of 1696 lncRNAs, 125 miRNAs, and 3246 mRNAs and 1784 lncRNAs, 96 miRNAs, and 3229 mRNAs with differentially expressed profiles were identified in the smoking and nonsmoking groups, respectively. The ceRNA network and survival analysis revealed four lncRNAs (LINC00466, DLX6-AS1, LINC00261, and AGBL1), one miRNA (hsa-mir-210), and two mRNAs (CITED2 and ENPP4), with the potential as biomarkers for smoking-related LUSC diagnosis and prognosis.

Conclusion

Taken together, our research has identified the differences in the ceRNA regulatory networks between smoking and nonsmoking LUSC, which could lay the foundation for future clinical research.

Dysregulation of pseudogene/lncRNA-hsa-miR-363-3p-SPOCK2 pathway fuels stage progression of ovarian cancer

Objective: Ovarian cancer is one of the most common and lethal cancer types in women. The molecular mechanism of ovarian cancer progression is still unclear.

Results: Here, we first reported that expression levels of three genes, GJB2, S100A2 and SPOCK2, were significantly higher in advanced stage than that in early stage of ovarian cancer, and upregulation of them indicated poor prognosis of patients with ovarian cancer. Subsequently, 8, 6 and 20 miRNAs were predicted to target GJB2, S100A2 and SPOCK2, respectively. Among these miRNA-mRNA pairs, hsa-miR-363-3p-SPOCK2 axis was the most potential in suppressing progression of ovarian cancer. Mechanistically, we found that hsa-miR-363-3p-SPOCK2 axis was involved in regulation of actin cytoskeleton. Moreover, 6 pseudogenes and 8 lncRNAs were identified to potentially inhibit hsa-miR-363-3p-SPOCK2 axis in ovarian cancer.

Conclusions: Collectively, we elucidate a regulatory role of pseudogene/lncRNA-hsa-miR-363-3p-SPOCK2 pathway in progression of ovarian cancer, which may provide effective therapeutic approaches and promising prognostic biomarkers for ovarian cancer.

Materials and methods: Differentially expressed genes (DEGs) in ovarian cancer were first screened using GSE12470, after which DEGs expression were validated using GEPIA. Kaplan-Meier analysis was employed to assess the prognostic values. Potential miRNAs were predicted by seven target prediction databases, and upstream lncRNAs and pseudogenes of hsa-miR-363-3p were forecasted through miRNet or starBase. UALCAN and starBase were used to obtain the co-expressed genes of SPOCK. Enrichment analysis for these co-expressed genes was performed by Enrichr.

LncRNA DLX6-AS1 increases the expression of HIF-1α and promotes the malignant phenotypes of nasopharyngeal carcinoma cells via targeting MiR-199a-5p

OBJECTIVE

To investigate the expression of long-chain noncoding growth stasis specific protein 6 antisense RNA1 (lncRNA DLX6-AS1) in nasopharyngeal carcinoma (NPC) tissues and cells, and its regulatory effect on malignant phenotypes of NPC cells.

METHODS

The expressions of DLX6-AS1, miR-199a-5p, and HIF-1α mRNA in NPC issues and cells were detected by qRT-PCR. The proliferation, metastasis, and invasion of cells were monitored via MTT and transwell assay. The interactions between DLX6-AS1 and miR-199a-5p, miR-199a-5p and HIF-1α were verified by luciferase activity assay. Western blot was performed to determine the regulatory effect of DLX6-AS1 and miR-199a-5p on HIF-1α protein.

RESULTS

The expression of lncRNA DLX6-AS1 was up-regulated in NPC tissues and cells. The proliferation, migration, and invasion of NPC were enhanced by overexpressed DLX6-AS1 but inhibited by DLX6-AS1 knockdown. In addition, DLX6-AS1 can be used as a kind of ceRNA to regulate miR-199a-5p and, thereby modulating the expression of HIF-1α.

CONCLUSION

We found that DLX6-AS1 was a cancer-promoting lncRNA to facilitate the progression of NPC, and its underlying mechanism was suppressing miR-199a-5p expression. This study can provide novel clues for the treatment of NPC.

Competing endogenous network analysis identifies lncRNA Meg3 activates inflammatory damage in UVB induced murine skin lesion by sponging miR-93-5p/epiregulin axis

In this study, we obtained the RNA expression data of murine skin tissues of control, and UVB irradiated groups. After the re-annotation of lncRNAs, a gene expression similarity analysis was done by WGCNA. The target mRNA prediction of lncRNAs, miRNAs, and ceRNA regulatory networks were constructed by five lncRNAs, 14 miRNAs and 54 mRNAs, respectively. Based on the ceRNA network of UVB-induced skin lesions, it was evident that the dysregulation of Meg3 has critical effects on the UVB-induced inflammatory lesion of murine skin tissues. The overexpression of Meg3 after UVB irradiation was observed in primary murine skin fibroblasts, and the up-regulated Meg3 expression was related to the activation of the inflammatory cytokines. These functional experiments demonstrated that the RNA silencing of Meg3 in murine skin fibroblasts could suppress the expression of the cytokines (in vitro) and UVB-induced skin lesions (in vivo). Moreover, the Meg3 functioned as a competing endogenous RNA (ceRNA) that acted as a sponge for miR-93-5p and thereby modulated the expression of Epiregulin (Ereg). Our results proved that Meg3 was involved in UVB-induced skin inflammation and that the ceRNA networks, which includes miR-93-5p and Ereg, could prove to be a potential therapeutic target for UVB-induced skin damage.

Downregulated long noncoding RNA LINC00313 inhibits the epithelial-mesenchymal transition, invasion, and migration of thyroid cancer cells through inhibiting the methylation of ALX4

Thyroid cancer represents one of the prevalent endocrine cancer with relatively high incidence rate around the world, accompanied by unchanged fatality rate. We probe into the specific role of LINC00313 in mediation of cellular processes of thyroid cancer including proliferation, migration, and invasion through the methylation of aristaless-like homeobox 4 (ALX4). Thyroid cancer-related long noncoding RNAs (lncRNAs) and genes were analyzed by microarray-based analysis. The antitumor effect of LINC00313 was examined with the gain- and loss-of-function experiments. In addition, the binding of LINC00313 and the promoter region of ALX4, and the interaction of LINC00313 with methylation-related proteins were detected. Later, xenograft tumors in nude mice were induced expecting to dig out the modulatory function of LINC00313 in tumor growth of thyroid carcinoma. The microarray-based analysis manifested that LINC00313 was overexpressed, whereas ALX4 was downregulated in thyroid cancer, the results of which were also verified in thyroid cancer tissues. Besides, our results demonstrated that LINC00313 bound to the ALX4 promoter region, and LINC00313 recruited DNMT1 and DNMT3B proteins to promote the methylation of ALX4 promoter region, thus suppressing the ALX4 expression. Finally, the downregulation of LINC00313 and upregulation of ALX4 repressed the AKT/mTOR signaling axis, thus inhibiting proliferative, migratory, invasive abilities as well as epithelial-to-mesenchymal transition (EMT) of thyroid cancer cells. Collectively, downregulated LINC00313 suppresses cell proliferation, migration, as well as invasion of thyroid cancer by inhibiting the methylation of ALX4 and increasing its expression by inactivation of the AKT/mTOR signaling pathway.

Construction of a competing endogenous RNA network using differentially expressed lncRNAs, miRNAs and mRNAs in non‑small cell lung cancer

The competing endogenous RNA (ceRNA) network is crucial for the development and progression of tumors, including non-small cell lung cancer (NSCLC). However, what type of ceRNA network regulates NSCLC has not been clarified. The present study aimed to elucidate the long non-coding RNA (lncRNA)/microRNA (miRNA)/mRNA ceRNA network in NSCLC, particularly for the significance of lncRNAs in NSCLC. NSCLC-specific differentially expressed lncRNAs, miRNAs and mRNAs in the Cancer Genome Atlas (TCGA) were analyzed and their relationship was analyzed by a ceRNA network. Their potential functions of differentially expressed mRNAs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Furthermore, the expression levels of four selected lncRNAs in TCGA were determined and their associated survival of patients was examined. In addition, the expression profiles of these four lncRNAs in 48 NSCLC specimens and cell lines, their cellular distribution and associated clinical parameters were examined. We successfully constructed a ceRNA network, including 113 lncRNAs, 12 miRNAs and 36 mRNAs differentially expressed between NSCLC and non-tumor tissues. LINC00525, MED4-AS1, STEAP2-AS1 and SYNPR-AS1 lncRNAs were selected and validated for their association with the survival of NSCLC patients. The expression of these lncRNAs was upregulated in 48 NSCLC tissues and was varying in NSCLC cells. While LINC00525 was mainly expressed in the cytoplasm, MED4-AS1 was in both the nucleus and cytoplasm of A549 cells. In addition, the expression of LINC00525 was significantly associated with smoking history (P<0.05); MED4-AS1 was significantly associated with women, poor differentiation and lymph node metastasis (P<0.05); STEAP2-AS1 was significantly associated with women (P<0.01); and SYNPR-AS1 was significantly associated with women and adenocarcinoma (P<0.05). These lncRNAs may be valuable biomarkers for prognosis of NSCLC and the ceRNA network may provide new insights in the pathogenesis of NSCLC.

lncRNA DLEU2 modulates cell proliferation and invasion of non-small cell lung cancer by regulating miR-30c-5p/SOX9 axis

Increasing evidence indicated that long noncoding RNAs (lncRNA) play critical roles in the progression of multiple cancers and that dysregulation of lncRNA promotes tumor progression. However, the function and underlying mechanism of lncRNA DLEU2 in biological behaviors of NSCLC cells are still largely unknown. Our studies confirmed that lncRNA DLEU2 was highly expressed in NSCLC tissues and cell lines, which was correlated with shorter overall survival in NSCLC patients. In vitro, knockdown of lncRNA DLEU2 inhibited proliferation, invasion, migration and induced apoptosis of both A549 and LLC cells; In vivo, it suppressed tumor growth and metastasis. lncRNA DLEU2 directly interacted with miR-30c-5p, which further targeted SOX9 and exerted oncogenic functions in NSCLC. Mechanistically, overexpression of lncRNA DLEU2 exhibits tumorigenic effects through downregulating the inhibitory effect of miR-30c-5p on SOX9 expression. In conclusion, Our finding confirmed that lncRNA DLEU2 as a novel oncogenic in NSCLC, which provide a potential novel diagnostic and therapeutic target for NSCLC.

MicroRNA-422a functions as a tumor suppressor in non-small cell lung cancer through SULF2-mediated TGF-β/SMAD signaling pathway

MicroRNAs (miRNAs) have been demonstrated to participate in a variety of human cancers by functioning as post-transcriptional regulators of oncogenes or antioncogenes including non-small cell lung cancer (NSCLC). The aim of the current study was to identify the role of miR-422a in NSCLC via sulfatase 2 (SULF2) to further elucidate the mechanism of NSCLC. Initially, the expression of miR-422a and SULF2 was determined in NSCLC tissues and cells. The role of miR-422a in NSCLC was identified in relation with a miR-422a mimic or inhibitor, siRNA against SULF2 and TGF-β1. The regulatory effects of miR-422a were examined following detection of the related epithelial mesenchymal transition (EMT)-related genes, and the apoptosis-related genes and evaluation of their cellular biological functions. The expression pattern of miR-422a, SULF2, and the TGF-β/SMAD pathway-related genes was detected to elucidate the mechanism by which miR-422a influences the progression of NSCLC. Finally, xenograft tumors in nude mice were observed for tumorigenicity evaluation purposes. Our results showed that miR-422a was poorly expressed while SULF2 was highly expressed in NSCLC. Dual luciferase reporter gene assay further verified that miR-422a targeted SULF2. Altogether, this study demonstrated that miR-422a downregulated SULF2 to inhibit the TGF-β/SMAD pathway. NSCLC cell proliferation, migration, invasion, colony formation, EMT and tumorigenesis were all inhibited while apoptosis was promoted upon restoration of miR-422a or silencing of SULF2. However, the activation of the TGF-β/SMAD pathway was determined to reverse the tumor-suppressive effects of si-SULF2. miR-422a restoration, which ultimately inhibited the progression of NSCLC by suppressing the TGF-β/SMAD pathway via SULF2.

Long non-coding RNA LINC00858 promotes cells proliferation, migration and invasion by acting as a ceRNA of miR-22-3p in colorectal cancer

Though long non-coding RNA LINC00858 (LINC00858) has been shown to be involved in tumours of other tissues, its involvement in colorectal cancer (CRC) is still unknown. We aimed to investigated expression and mechanism LINC00858 in human CRC. In this study, we firstly found that LINC00858 expression was significantly up-regulated in both CRC tissues and cell lines by both online data and RT-PCR assay. Then, clinical assay revealed that high LINC00858 expression was significantly associated with advanced clinical progression and poor prognosis. Multivariate analysis demonstrated that high LINC00858 expression was an independent poor prognostic factor for CRC patients. Moreover, lost-of-function assay indicated that knockdown of LINC00858 suppressed CRC cells proliferation, migration and invasion, and promoted apoptosis. Mechanistically, bioinformatics analysis, dual-luciferase reporter assays, and western blot assays showed that LINC00858 functioned as competing endogenous RNA to repress miR-22-3p, which controlled its down-stream target YWHAZ. Then, we suggested that LINC00858 exerted its function through the miR-22-3p/YWHAZ axis. To our knowledge, this is the first report which showed the role of LINC00858 in the progression of CRC. Our findings indicated that LINC00858 played an important role in CRC, and may serve as a novel prognostic factor and therapeutic target.

Kallikrein-related peptidases in lung diseases

Human tissue kallikreins (KLKs) are 15 members of the serine protease family and are present in various healthy human tissues including airway tissues. Multiple studies have revealed their crucial role in the pathophysiology of a number of chronic, infectious and tumour lung diseases. KLK1, 3 and 14 are involved in asthma pathogenesis, and KLK1 could be also associated with the exacerbation of this inflammatory disease caused by rhinovirus. KLK5 was demonstrated as an influenza virus activating protease in humans, and KLK1 and 12 could also be involved in the activation and spread of these viruses. KLKs are associated with lung cancer, with up- or downregulation of expression depending on the KLK, cancer subtype, stage of tumour and also the microenvironment. Functional studies showed that KLK12 is a potent pro-angiogenic factor. Moreover, KLK6 promotes malignant-cell proliferation and KLK13 invasiveness. In contrast, KLK8 and KLK10 reduce proliferation and invasion of malignant cells. Considering the involvement of KLKs in various physiological and pathological processes, KLKs appear to be potential biomarkers and therapeutic targets for lung diseases.

Long noncoding RNA LINC00858 promotes osteosarcoma through regulating miR-139-CDK14 axis

Long noncoding RNAs (lncRNAs) have been identified to modulate the tumorigenesis of human cancers. The in-depth of lncRNAs on human osteosarcoma oncogenesis is still ambiguous. In present study, functional and mechanism experiments were conducted to investigate the role of long intergenic non-protein coding RNA 00858 (LINC00858) on human osteosarcoma tumorigenesis. Results demonstrated that LINC00858 expression was significantly upregulated in both osteosarcoma tissues and cell lines. Mechanism assays presented that LINC00858 silencing significantly repressed osteosarcoma cells' proliferation and invasion in vitro, and inhibited the tumor growth in vivo. In further experiments, LINC00858 was identified to sponge miR-139 to form RNA-induced silencing complex (RISC) using luciferase reporter assay and RNA immunoprecipitation (RIP). Besides, CDK14 was validated to be the target protein the miR-139. Rescue experiments confirmed the role of LINC00858/miR-139/CDK14 pathway on osteosarcoma cells' phenotype. In summary, these data prove that LINC00858/miR-139/CDK14 axis promotes the tumorigenesis of osteosarcoma, providing a new mechanism or target for osteosarcoma.

MicroRNA in lung cancer: role, mechanisms, pathways and therapeutic relevance

Lung cancer is the cardinal cause of cancer-related deaths with restricted recourse of therapy throughout the world. Clinical success of therapies is not very promising due to - late diagnosis, limited therapeutic tools, relapse and the development of drug resistance. Recently, small ∼20-24 nucleotides molecules called microRNAs (miRNAs) have come into the limelight as they play outstanding role in the process of tumorigenesis by regulating cell cycle, metastasis, angiogenesis, metabolism and apoptosis. miRNAs essentially regulate gene expression via post-transcriptional regulation of mRNA. Nevertheless, few studies have conceded the role of miRNAs in activation of gene expression. A large body of data generated by numerous studies is suggestive of their tumor-suppressing, oncogenic, diagnostic and prognostic biomarker roles in lung cancer. They have also been implicated in regulating cancer cell metabolism and resistance or sensitivity towards chemotherapy and radiotherapy. Further, miRNAs have also been convoluted in regulation of immune checkpoints - Programmed death 1 (PD-1) and its ligand (PD-L1). These molecules play a significant role in tumor immune escape leading to the generation of a microenvironment favouring tumor growth and progression. Therefore, it is imperative to explore the expression of miRNA and understand its relevance in lung cancer and development of anti-cancer strategies (anti - miRs, miR mimics and micro RNA sponges). In view of the above, the role of miRNA in lung cancer has been dissected and the associated mechanisms and pathways are discussed in this review.

The Long Noncoding RNA D63785 Regulates Chemotherapy Sensitivity in Human Gastric Cancer by Targeting miR-422a

Gastric cancer is one of the most prevalent tumor types in the world. Chemotherapy is the most common choice for cancer treatment. However, chemotherapy resistance and adverse side effects limit its clinical applications. Aberrant expression of long noncoding RNAs (lncRNAs) has been found in various stages of gastric cancer development and progression. In this study, we identified that an oncogenic lncRNA, long intergenic non-protein-coding RNA D63785 (lncR-D63785), is highly expressed in gastric cancer tissues and cells. Silencing of lncR-D63785 inhibited cell proliferation, cell migration and invasion in gastric cancer cell lines and reduced tumor volume and size in mice. We found that the expression of lncR-D63785 was inversely correlated with microRNA 422a (miR-422a) expression, which was involved in the downregulation of expression of myocyte enhancer factor-2D (MEF2D) and drug sensitivity. Knockdown of lncR-D63785 increased the expression of miR-422a and the sensitivity of gastric cancer cells to apoptosis induced by the anticancer drug doxorubicin (DOX). This indicates that lncR-D63785 acts as a competitive endogenous RNA (ceRNA) of miR-422a and promotes chemoresistance by blocking miR-422-dependent suppression of MEF2D. Together, our results suggest that the therapeutic suppression of lncR-D63785 alone or in combination with chemotherapeutic agents may be a promising strategy for treating gastric cancer.

Long noncoding RNA NEAT1 regulate papillary thyroid cancer progression by modulating miR-129-5p/KLK7 expression

Considering the dilemma in papillary thyroid cancer treatment, this study intended to find solution in molecular respect. By probing into lncRNA-NEAT1/miR-129-5p/KLK7 interaction, this study would provide new targets for future treatment. Microarray analysis and R language package were applied to select possible lncRNA and miRNA. Luciferase reporter assay and RNA pull-down test were employed in the detection of target relationship between lncRNA and miRNA. Clone formation assay, flow cytometry analysis, wound healing assay, and transwell assay were, respectively, used to observe effects of lncRNA NEAT1/miR-129-5p/KLK7 to papillary thyroid cancer cells. Western blot and qRT-PCR were used to validate protein expressions and mRNA expressions in PTC tissues and cells. LncRNA NEAT1 was highly expressed in PTC tissues and cell lines and could deteriorate PTC by promoting proliferation, invasion, and migration accompanied by less apoptosis. Besides, miR-129-5p/lncRNA NEAT1 were found to negatively correlate with each other by direct target relationship and their combination suppressed the progression of PTC. KLK7, a highly expressed downstream protein in PTC tissues, could be directly regulated by miR-129-5p in a negative way. KLK7 accelerated the deterioration of PTC in vitro experiments which could be reversed by sh-lnc RNA NEAT1 and miR-129-5p mimics. In vivo experiments, silence of lncRNA NEAT1 restrain tumor growth in weight and volume. In conclusion, lncRNA NEAT1 suppression could inhibit PTC progression by upregulating miR-129-5p, which suppressed KLK7 expression either in vitro or vivo experiments.

Upregulated lncRNA ADAMTS9-AS2 suppresses progression of lung cancer through inhibition of miR-223-3p and promotion of TGFBR3

In this study, we aimed at investigating effects of lncRNA ADAMTS9-AS2 on lung cancer progression through regulating miR-223-3p and TGFBR3 expressions. Expressions of ADAMTS9-AS2 in lung cancer tissues and cell lines were determined by reverse transcriptase polymerase chain reaction (qRT-PCR). TargetScan and miRcode were used to predict the targeting relationships, respectively. The luciferase reporter system was used to verify that the relationship among ADAMTS9-AS2, TGFBR3 and miR-223-3p. Western blot assay tested the protein level changes in TGFBR3. Cell proliferation was determined by CCK-8 assay. Cell cycle and cell apoptosis were detected by flow cytometry assay, and migration and invasion were determined by transwell assay. Tumor xenograft model was developed to study the influence of ADAMTS9-AS2 on tumor growth in vivo. qRT-PCR results demonstrated that lncADAMTS9-AS2 was lowly expressed in lung cancer tissues. High expression of ADAMTS9-AS2 in lung cancer cells significantly reduced proliferation ability and inhibited migration, as well as elevating their apoptosis rate. In vivo assay found that ADAMTS9-AS2 suppressed the lung tumor growth. Bioinformatics predicted that miR-223-3p bound directly to the ADAMTS9-AS2 and TGFBR3, which was later confirmed by luciferase reporter system. ADAMTS9-AS2 transfection increased TGFBR3 mRNA and protein expressions in lung cancer cells, but miR-223-3p transfection significantly decreased them. Besides, our results showed that miR-223-3p induced cellular apoptosis while TGFBR3 group showed the complete opposite effect. It was proved that ADAMTS9-AS2 and TGFBR3 were the direct genes of miR-223-3p. MiR-223-3p promotes proliferation, migration and invasion of lung cancer cells by targeting TGFBR3. Therefore, ADAMTS9-AS2, miR-223-3p and TGFBR3 may provide potential targets for the treatment of lung cancer patients. © 2018 IUBMB Life, 70(6):536-546, 2018.

MiR-422a weakened breast cancer stem cells properties by targeting PLP2

OBJECTIVE

This study investigated miR-422a and PLP2 expressions in breast cancer cells and breast cancer stem cells (BCSCs). Besides, their influences on polymorphism changes were observed.

METHODS

Flow cytometry and fluorescence-activated cell sorting was performed and CD24^-/CD44⁺ cells were sorted from breast cancer cells and recognized as BCSCs. Microarray was applied to search for the differentially expressed miRNAs and mRNAs between MCF7 and BCSCs. The aberrant expression of miR-422a and PLP2 was further confirmed by RT-qPCR and the direct targeted relationship was verified by dual-luciferase reporter assay. After in vitro transfection, the expression of miR-422a and PLP2 were manipulated and biological functions of BMSCs were compared with CCK-8, colony formation and sphere formation assay. The tumorigenesis ability of transfected BMSCs was also investigated in NOD/SCID tumor mice models.

RESULTS

BMSCs were successfully established from MCF7 cells and miR-422a expression was downregulated while PLP2 level decreased in BMSCs. MiR-422a directly targets the 3'UTR of PLP2 and suppressed its expression. Besides, the up-regulation of miR-422a contributed to weakened ability of proliferation and microsphere formation of BMSCs, while PLP2 overexpression facilitated those biological abilities. Tumorigenesis of BMSCs in mice models was impaired by either overexpression of miR-442a or silencing of PLP2.

CONCLUSION

Up-regulation of miR-422a attenuated microsphere formation, proliferation and tumor formation of breast cancer stem cells via suppressing the PLP2 expression.

MiR-422a targets MAPKK6 and regulates cell growth and apoptosis in colorectal cancer cells

The important role of miR-422a in tumor has been reported in several studies. Recent research discovered that the expression of miR-422a was significantly decreased in colorectal cancer tissues, providing miR-422a as a tumor suppressor in CRC. However, the concrete mechanism of miR-422a regulating CRC cell is still unclear. In this study, we demonstrated that miR-422a could inhibit CRC cell growth and promote cell apoptosis via in vitro analyses. Moreover, computational methods were adopted to identify the targets of miR-422a. We found MAPKK6 was the direct target of miR-422a. Consequently, we further elucidated that miR-422a inhibited CRC cell growth and induced cell apoptosis by inhibiting p38/MAPK pathway. Besides that, we established the tumor xenograft model using nude mice and the inhibitory effects on tumor volumes and weights by miR-422a mimic transfection were also detected. Taken together, these findings demonstrated miR-422a exerted anti-cancer activities on CRC, which could be potentially used for CRC prognosis prediction and treatment.

Long noncoding RNA DLX6-AS1 promotes renal cell carcinoma progression via miR-26a/PTEN axis

Recently, long non-coding RNAs (lncRNAs) have emerged as new gene regulators and prognostic markers in several types of cancer, including renal cell carcinoma (RCC). In this study, we identified an upregulated lncRNA, DLX6-AS1, in RCC tumor tissues compared with normal kidney tissues. Our data suggested that DLX6-AS1 promoted RCC cell growth and tumorigenesis via targeting miR-26a. In addition, we observed that PTEN overexpression restored the renal cancer cell growth and also rescued the RCC tumorigenesis. In summary, we conclude that DLX6-AS1 promotes renal cell carcinoma development via regulation of miR-26a/PTEN axis.

Integrated analysis of competing endogenous RNA network revealing lncRNAs as potential prognostic biomarkers in human lung squamous cell carcinoma

Accumulating evidence shows the important role of long non-coding RNAs (lncRNAs) in competing endogenous RNA (ceRNA) networks for predicting survival in tumor patients. However, prognostic biomarkers for lung squamous cell carcinoma (LUSC) are still lacking. The objective of this study is to identify a lncRNA signature for evaluation of overall survival (OS) in 474 LUSC patients from The Cancer Genome Atlas (TCGA) database. A total of 474 RNA sequencing profiles in LUSC patients with clinical data were obtained, providing a large sample of RNA sequencing data, and 83 LUSC-specific lncRNAs, 26 miRNAs, and 85 mRNAs were identified to construct the ceRNA network (fold change>2, P<0.05). Among these above 83 LUSC-specific lncRNAs, 22 were assessed as closely related to OS in LUSC patients using a univariate Cox proportional regression model. Meanwhile, two (FMO6P and PRR26) of the above 22 OS-related lncRNAs were identified using a multivariate Cox regression model to construct a risk score as an independent indicator of the prognostic value of the lncRNA signature in LUSC patients. LUSC patients with low-risk scores were more positively correlated with OS (P<0.001). The present study provides a deeper understanding of the lncRNA-related ceRNA network in LUSC and suggests that the two-lncRNA signature could serve as an independent biomarker for prognosis of LUSC.