LncRNA TTN-AS1 drives invasion and migration of lung adenocarcinoma cells via modulation of miR-4677-3p/ZEB1 axis

Differential expression and clinical significance of long non-coding RNAs in the development and progression of lung adenocarcinoma

With the development of gene testing technology, we have found many different genes, and lncRNA is one of them. LncRNAs refer to a non-protein coding RNA molecule with a length of more than 200bp, which is one of the focuses of research on human malignant diseases such as LUAD. LncRNAs act as an oncogene or inhibitor to regulate the occurrence and progression of tumors. The differential expression of LncRNAs promotes or inhibits the progression of lung adenocarcinoma by affecting cell proliferation, metastasis, invasion, and apoptosis, thus affecting the prognosis and survival rate of patients. Therefore, LncRNAs can be used as a potential target for diagnosis and treatment of cancer. The early diagnosis of the disease was made through the detection of tumor markers. Because lung adenocarcinoma is not easy to diagnose in the early stage and tumor markers are easy to ignore, LncRNAs play an important role in the diagnosis and treatment of lung adenocarcinoma. The main purpose of this article is to summarize the known effects of LncRNAs on lung adenocarcinoma, the effect of differential expression of LncRNAs on the progression of lung adenocarcinoma, and related signal transduction pathways. And to provide a new idea for the future research of lung adenocarcinoma-related LncRNAs.

High SNHG expression may predict a poor lung cancer prognosis based on a meta-analysis

BACKGROUND

An increasing number of small nucleolar RNA host genes (SNHGs) have been revealed to be dysregulated in lung cancer tissues, and abnormal expression of SNHGs is significantly correlated with the prognosis of lung cancer. The purpose of this study was to conduct a meta-analysis to explore the correlation between the expression level of SNHGs and the prognosis of lung cancer.

METHODS

A comprehensive search of six related databases was conducted to obtain relevant literature. Relevant information, such as overall survival (OS), progression-free survival (PFS), TNM stage, lymph node metastasis (LNM), and tumor size, was extracted. Hazard ratios (HRs) and 95% confidence intervals (CIs) were pooled to evaluate the relationship between SNHG expression and the survival outcome of lung cancers. Sensitivity and publication bias analyses were performed to explore the stability and reliability of the overall results.

RESULTS

Forty publications involving 2205 lung cancer patients were included in this meta-analysis. The pooled HR and 95% CI values indicated a significant positive association between high SNHG expression and poor OS (HR: 1.890, 95% CI: 1.595-2.185), disease-free survival (DFS) (HR: 2.31, 95% CI: 1.57-3.39) and progression-free survival (PFS) (HR: 2.01, 95% CI: 0.66-6.07). The pooled odds ratio (OR) and 95% CI values indicated that increased SNHG expression may be correlated with advanced TNM stage (OR: 1.509, 95% CI: 1.267-1.799), increase risk of distant lymph node metastasis (OR: 1.540, 95% CI: 1.298-1.828), and large tumor size (OR: 1.509, 95% CI: 1.245-1.829). Sensitivity analysis and publication bias results showed that each result had strong reliability and robustness, and there was no significant publication bias or other bias.

CONCLUSION

Most SNHGs are upregulated in lung cancer tissues, and high expression of SNHGs predicts poor survival outcomes in lung cancer. SNHGs may be potential prognostic markers and promising therapeutic targets.

Prognostic significance of long noncoding RNA TTN-AS1 in various malignancies

BACKGROUND

Increasing evidence has demonstrated that high TTN-AS1 expression is highly related to poor prognosis in diverse human cancers. However, the findings concerning the prognostic value of TTN-AS1 were inconsistent, as these conclusions were usually drawn with relatively small sample sizes. Hence, this meta-analysis proposes to investigate the prognostic significance of TTN-AS1 in multiple malignancies systematically.

METHODS

Web of Science, Springer, Embase, PubMed, Cochrane Library, and Scopus databases were comprehensively searched to retrieve studies related to the TTN-AS1 expression with the prognosis of malignancies. The significance of the TTN-AS1 in cancers was estimated by hazard ratios (HRs) or odds ratios (ORs). Additionally, the Gene Expression Profiling Interactive Analysis (GEPIA) analysis tool was used to strengthen our results further.

RESULTS

Twenty studies involving 17 different cancers and 1330 patients were recruited into this meta-analysis. The research revealed that high TTN-AS1 expression was remarkably associated with unfavorable overall survival (OS) (HR = 2.07, 95%CI [1.78, 2.41], p < .00001) when compared with low TTN-AS1 expression in malignancies. Additionally, elevated TTN-AS1 expression significantly contributed to lymph node metastasis (OR = 4.09, 95%CI [3.08, 5.44], p < .0001), larger tumor size (OR = 2.42, 95%CI [1.56, 3.77], p < .0001), worse tumor differentiation (OR = 0.36, 95%CI [0.22, 0.59], p < .0001) and more advanced tumor stage (OR = 0.29, 95%CI [0.22, 0.38], p < .0001) with low or no heterogeneity existing. Moreover, high TTN-AS1 expression  was connected with worse disease-free survival in five different cancers based on the GEPIA online database.

CONCLUSIONS

The results of this meta-analysis support that high TTN-AS1 expression significantly correlates with worse prognosis in various cancers. Therefore, TTN-AS1 may be considered as a novel biomarker for malignancies.

TTN-AS1 delivered by gastric cancer cell-derived exosome induces gastric cancer progression through in vivo and in vitro studies

Extracellular communication within the tumor microenvironment exerts critical functions in tumor progression. Moreover, exosomes are capable of packaging into long non-coding RNAs (lncRNAs) to regulate extracellular communication. We tried to discuss the role of exosomal lncRNA TTN-AS1 and its molecular mechanism on gastric cancer (GC) progression. Bioinformatics analysis depicted increased TTN-AS1 in GC which shared correlation with poor prognosis. Clinical tissue and cellular experiments also confirmed the elevation of TTN-AS1 in GC tissues and cells. GC cell (AGS)-derived Exo could be uptake by NCI-N87 cells to induce malignant features of GC cells. Functionally, TTN-AS1 could upregulate ZEB1 expression by binding to miR-499a-5p. In addition, in vitro experiments demonstrated that ZEB1 targeted and activated CDX2 transcription and promoted CDX2 expression; silencing CDX2 inhibited malignant phenotypes of AGS and NCI-N87 cells. Furthermore, Exo-TTN-AS1 promoted GC cell growth and migration by promoting CDX2 expression. Exosomal TTN-AS1 from GC cells could also promote metastasis of GC in vivo. In conclusion, our findings provided evidence describing that exosomes derived from GC cells transferred TTN-AS1 to GC cells, which aggravate GC through the miR-499a-5p/ZEB1/CDX2 axis. 1. Exo derived from GC cells promotes the growth and metastasis of GC cells by carrying TTN-AS1. 2. TTN-AS1 acts as a ceRNA to adsorb miR-499a-5p to regulate the expression of ZEB1. 3. ZEB1 targets and activates CDX2 transcription. 4. GC cell-derived Exo-TTN-AS1 enhances the growth and metastasis of GC cell xenografts in vivo.

The functions of long noncoding RNAs on regulation of F-box proteins in tumorigenesis and progression

Accumulated evidence has revealed that F-box protein, a subunit of SCF E3 ubiquitin ligase complexes, participates in carcinogenesis and tumor progression via targeting its substrates for ubiquitination and degradation. F-box proteins could be regulated by cellular signaling pathways and noncoding RNAs in tumorigenesis. Long noncoding RNA (lncRNA), one type of noncoding RNAs, has been identified to modulate the expression of F-box proteins and contribute to oncogenesis. In this review, we summarize the role and mechanisms of multiple lncRNAs in regulating F-box proteins in tumorigenesis, including lncRNAs SLC7A11-AS1, MT1JP, TUG1, FER1L4, TTN-AS1, CASC2, MALAT1, TINCR, PCGEM1, linc01436, linc00494, GATA6-AS1, and ODIR1. Moreover, we discuss that targeting these lncRNAs could be helpful for treating cancer via modulating F-box protein expression. We hope our review can stimulate the research on exploration of molecular insight into how F-box proteins are governed in carcinogenesis. Therefore, modulation of lncRNAs is a potential therapeutic strategy for cancer therapy via regulation of F-box proteins.

Long noncoding RNA ArfGAP with RhoGAP domain, ankyrin repeat and PH domain 1 antisense RNA 1 recruits enhancer of zeste 2 polycomb repressive complex 2 subunit to promote the proliferation, migration and invasion of lung adenocarcinoma cells

The detailed function of ARAP1-AS1, the antisense RNA of Arf-GAP with Rho-GAP domain, ANK repeat and PH domain-containing protein 1 (ARAP1), in lung adenocarcinoma (LUAD) has not been clearly elucidated and required further investigation. Our study is committed to exploring the role of ARAP1-AS1 in LUAD. Gene expression in LUAD was measured by real-time quantitative polymerase-chain reaction (RT-qPCR). The influence of ARAP1-AS1 on LUAD cell malignant behaviors was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay, Transwell invasion assay and wound healing assay. Subcellular fractionation assay detected the cellular localization of ARAP1-AS1 in LUAD. The protein levels were subjected to western blotting. RNA immunoprecipitation (RIP) and luciferase reporter assay were employed to verify the interaction between ARAP1-AS1, ARAP1 and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). Our investigation identified that ARAP1-AS1 was upregulated in LUAD cells and tissues. ARAP1-AS1 silencing repressed LUAD cell growth and migration. Furthermore, ARAP1-AS1 knockdown altered the expression of its sense mRNA, ARAP1. ARAP1-AS1 could recruit EZH2 to inhibit ARAP1 expression. Additionally, the downregulation of ARAP1 reversed ARAP1-AS1 downregulation-induced repression of cell growth and migration in LUAD. In conclusion, ARAP1-AS1 recruited EZH2 to silence ARAP1, facilitating cell proliferation, migration and invasion in LUAD. Our study demonstrated the possibility of ARAP1-AS1 to be a novel therapeutic target for LUAD.

TTN-AS1 accelerates the growth and migration of nasopharyngeal carcinoma cells via targeting miR-876-5p/NETO2

Nasopharyngeal carcinoma (NPC) is one of the most predominant cancers occurring in China with high morbidity. Lately, large quantities of long non-coding RNAs (lncRNAs) have been highlighted to regulate the biological activities in multiple tumors, including NPC. Our study centered on whether TTN-AS1 was involved in NPC and how it modulated the progression of NPC. Here, qRT-PCR data uncovered that TTN-AS1 expression was conspicuously high in NPC cells. Based on the results of functional assays, TTN-AS1 silence hampered the proliferative, migratory, and invasive abilities but stimulated the apoptotic capability of NPC cells. After a series of mechanism assays, TTN-AS1 was found to competitively bind with miR-876-5p and recruit UPF1 to enhance NETO2 expression. In addition, TTN-AS1 could be transcriptionally activated by YY1 in NPC cells. It was also found that miR-876-5p overexpression or NETO2 downregulation had inhibitory effects on cell proliferation, migration, and invasion in NPC. Moreover, NETO2 upregulation could restore the suppressive impacts of TTN-AS1 depletion on NPC cell and tumor growth. In conclusion, YY1-activated TTN-AS1 interacted with both miR-876-5p and UPF1 to upregulate NETO2, thus strengthening NPC cell malignant behaviors, which might provide more useful information for people to develop effective NPC treatments.

LncRNA VPS9D1-AS1 Promotes Malignant Progression of Lung Adenocarcinoma by Targeting miRNA-30a-5p/KIF11 Axis

Objective: This research probed into the molecular mechanisms of long non-coding RNA (lncRNA) VPS9D1 Antisense RNA 1 (VPS9D1-AS1) in lung adenocarcinoma (LUAD).

Methods: lncRNA expression level was evaluated bioinformatically, and its downstream miRNA/mRNA regulatory axis was predicted by bioinformatics methods as well. qRT-PCR was used to measure VPS9D1-AS1, miRNA-30a-5p, and kinesin family member 11 (KIF11) expression. Western blot was performed to measure KIF11 protein expression. Proliferation, migration, and invasion of LUAD cells were all observed by cell biological function experiments. Dual-luciferase assay detected binding between miRNA-30a-5p and VPS9D1-AS1 or KIF11, respectively. RIP experiment detected interaction between VPS9D1-AS1 and miRNA-30a-5p.

Results: VPS9D1-AS1 and KIF11 were increased in LUAD, whereas miRNA-30a-5p was decreased. VPS9D1-AS1 promoted the malignant progression of LUAD cells and could sponge miRNA-30a-5p. MiRNA-30a-5p could restore the impact of VPS9D1-AS1 on LUAD cells. KIF11 was a target downstream of miRNA-30a-5p. VPS9D1-AS1 could upregulate KIF11 expression through competitively sponging miRNA-30a-5p, and KIF11 could restore the impact of miRNA-30a-5p on LUAD cells.

Conclusion: VPS9D1-AS1 could foster malignant progression of LUAD via regulating miRNA-30a-5p/KIF11 axis, suggesting that VPS9D1-AS1 is key to regulating the malignant progression of LUAD.

Hsa_circ_0024093 accelerates VSMC proliferation via miR-4677-3p/miR-889-3p/USP9X/YAP1 axis in in vitro model of lower extremity ASO

Arteriosclerosis obliterans (ASO) of the lower extremities is identified as a kind of cardiovascular disease with aberrant proliferation and apoptosis of vascular smooth muscle cells (VSMCs). Accumulating studies have demonstrated the vital role of Yes1-associated transcriptional regulator (YAP1) in VSMCs, while its upstream regulatory mechanism in VSMCs in ASO of the lower extremities needs to be further elucidated. Herein, hsa_circ_0024093, a circular RNA (circRNA) from YAP1, was identified to positively regulate the protein level of YAP1 in VSMCs. Functionally, silencing of hsa_circ_0024093 obviously impeded cell proliferation and migration and promoted apoptosis in VSMCs in the in vitro model of ASO of the lower extremities. Mechanistically, it was found that hsa_circ_0024093 could regulate the expression of USP9X, which further induced YAP1 deubiquitination to stabilize YAP1 protein. In depth, it was revealed from mechanism experiments that hsa_circ_0024093 sequestered miR-889-3p or miR-4677-3p to enhance USP9X expression. Further, rescue assays validated that hsa_circ_0024093 regulated the miR-4677-3p/miR-889-3p/USP9X axis to accelerate the proliferation and migration of VSMCs in the in vitro model of ASO of the lower extremities. These findings may provide a novel perspective for better understanding of ASO of the lower extremities.

Silencing of Long Non-coding RNA TTN-AS1 Inhibits Hepatocellular Carcinoma Progression by the MicroRNA-134/ITGB1 Axis

BACKGROUND

Hepatocellular carcinoma (HCC) causes considerable mortality worldwide. Long non-coding RNA (lncRNA) TTN-AS1 has been recently identified as an oncogene in several cancers, but its role in HCC and the molecules remain largely unknown.

AIMS

The study aims to probe the function of lncRNA TTN-AS1 in HCC progression and the molecules involved.

METHODS

Differentially expressed lncRNAs between HCC and the adjacent normal tissues were analyzed using a microarray. TTN-AS1 expression in HCC and normal tissues and cells was determined. Targeting relationships between TTN-AS1 and miR-134 and between miR-134 and ITGB1 were validated. Artificial up-regulation or down-regulation of TTN-AS1, miR-134 and ITGB1 was introduced in HCC cells to probe their effects on the biological behaviors of HCC cells. Xenograft tumors were induced in nude mice for in vivo experiments.

RESULTS

TTN-AS1 and ITGB1 were highly expressed, while miR-134 was poorly expressed in HCC tissues. TTN-AS1 enforced ITGB1 expression through sequestering miR-134. Silencing of TTN-AS1 or over-expression of miR-134 inhibited proliferation, invasion, migration, and resistance to death of Huh7 cells. Following miR-134 silencing, further down-regulation of ITGB1 suppressed the malignant behaviors of HUH7 cells. The similar results were reproduced in vivo.

CONCLUSION

The current study provided evidence that TTN-AS1 might promote HCC progression through sponging miR-134 and the following ITGB1 up-regulation. TTN-AS1 may serve as a potential target for HCC treatment.

Long noncoding RNA LINC01287 promotes proliferation and inhibits apoptosis of lung adenocarcinoma cells via the miR-3529-5p/RNASEH2A axis under the competitive endogenous RNA pattern

Lung adenocarcinoma (LUAD) is regarded as the most common type of lung cancer. The molecular targeted therapies for LUAD have being extensively studied. Ribonuclease H2 subunit A (RNASEH2A) is a nucleotide degrading enzyme gene that exerts great influence on cell proliferation, DNA replication and genomic stability. According to bioinformatics analysis, RNASEH2A expression in LUAD tissues is predicted to be upregulated and high expression of RNASEH2A might be related to lower survival rate in LUAD patients. In the present study, we investigated functions of RNASEH2A in LUAD. The mRNA RNASEH2A showed high expression in LUAD cells, and its knockdown inhibited proliferation and induced apoptosis in LUAD cells. RNASEH2A was found to be a target gene of microRNA miR-3529-5p after their expression levels and interaction being examined. Long noncoding RNA LINC01287 upregulated RNASEH2A expression in LUAD cells by combining with miR-3529-5p in a competitive way. Rescue assays revealed that the overexpression of RNASEH2A reversed the suppression of cell proliferation and the promotion of cell apoptosis induced by miR-3529-5p overexpression or LINC01287 knockdown. Finally, forkhead box A1 (FOXA1) interacted with RNASEH2A promoter and LINC01287 promoter to upregulate the expression levels of RNASEH2A and LINC01287 in LUAD cells. Overall, FOXA1-induced LINC01287 serves as a competing endogenous RNA to promote proliferation and inhibit apoptosis of LUAD cells via upregulation of RNASEH2A expression at the posttranscriptional level by competitively combining with miR-3529-5p.

miR-4677-3p participates proliferation and metastases of gastric cancer cell via CEMIP-PI3K/AKT signaling pathway

Gastric cancer is one of the top three leading causes of cancer-related death in the world. Evidence indicated that miR-4677-3p was dysregulated and involved in modulating invasion and migration in multiple types of cancer cells. The aim of this research is to explore the function and mechanism of miR-4677-3p in the development of gastric cancer. In this study, we discovered that miR-4677-3p was down-regulated in gastric cancer tissues and cells. Over-expression of miR-4677-3p suppressed the proliferation, migration and invasion of gastric cancer cells. Furthermore, miR-4677-3p directly bond to CEMIP 3'UTR region and inhibited CEMIP expression. CEMIP promoted cell proliferation, migration and invasion of gastric cancer cells via accelerating PI3K/AKT signaling pathway. siCEMIP or PI3K/AKT signaling inhibitor (Akti-1/2 and LY294002) partly reversed the effects of miR-4677-3p on the cellular growth and metastasis of gastric cancer. In general, miR-4677-3p regulated the development of gastric cancer through CEMIP-PI3K/AKT signaling pathway axis. This study verified the function and molecular mechanism of miR-4677-3p in gastric cancer cells, and may provide a potential diagnosis/prognosis target for patients with gastric cancer.

Multi-Omics Integrative Bioinformatics Analyses Reveal Long Non-coding RNA Modulates Genomic Integrity via Competing Endogenous RNA Mechanism and Serves as Novel Biomarkers for Overall Survival in Lung Adenocarcinoma

Long non-coding RNA (lncRNA) plays a crucial role in modulating genome instability, immune characteristics, and cancer progression, within which genome instability was identified as a critical regulator in tumorigenesis and tumor progression. However, the existing accounts fail to detail the regulatory role of genome instability in lung adenocarcinoma (LUAD). We explored the clinical value of genome instability-related lncRNA in LUAD with multi-omics bioinformatics analysis. We extracted the key genome instability-related and LUAD-related gene modules using weighted gene co-expression network analysis (WGCNA) and established a competing endogenous RNA (ceRNA) network using four lncRNAs (LINC01224, LINC00346, TRPM2-AS, and CASC9) and seven target mRNAs (CCNF, PKMYT1, GCH1, TK1, PSAT1, ADAM33, and DDX11). We found that LINC01224 is primarily located in the cytoplasm and that LINC00346 and TRPM2-AS are primarily located in the nucleus (CASC9 unknown). We found that all 11 genes were positively related to tumor mutational burden and involve drug resistance, cancer stemness, and tumor microenvironment infiltration. Additionally, an eight-lncRNA genome instability-related lncRNA signature was established and validated, predicting the overall survival and immunotherapy outcomes in LUAD. To conclude, we discovered that sponging microRNA, genome instability-related lncRNA functions as ceRNA, modulating genomic integrity. This research provides clinical references for LUAD immunotherapy and prognosis and interprets a potential genome instability-related ceRNA regulatory network in which LINC01224-miR-485-5p/miR-29c-3p-CCNF-RRM2 and LINC01224-miR485-5p-PKMYT1-CDK1 axes were the most promising pathways. However, the potential mechanisms underlying our findings still need biological validation through in vitro and in vivo experiments.

GLIDR promotes the progression of glioma by regulating the miR-4677-3p/MAGI2 axis

Gliomas are the most common and fatal primary brain tumors. Growing evidence suggests that long non-coding RNAs (lncRNAs) constitute novel and potential therapeutic targets for glioma. However, the biological role of glioblastoma down-regulated RNA (GLIDR) in glioma remains largely elusive. In the current study, we used quantitative real-time polymerase chain reaction (qRT-PCR) to detect GLIDR expression in glioma cells. Cell counting kit 8 (CCK-8) assay, colony formation assay, JC-1 staining, and flow cytometry were used to evaluate the role of GLIDR in proliferation and apoptosis of glioma cells. Western blotting was performed to assess the effect of GLIDR on the level of apoptosis-related proteins. In addition, bioinformatics prediction, RNA immunoprecipitation (RIP), RNA pull-down, and luciferase reporter gene assays were used to study the regulatory mechanisms of GLIDR in glioma. GLIDR was found to be highly expressed in glioma cells and silencing of GLIDR inhibited cell proliferation and promoted apoptosis. Functionally, GLIDR bound to miR-4677-3p that directly targeted membrane-associated guanylate kinase, WW, and PDZ domain-containing protein 2 (MAGI2). Our data showed that GLIDR affects the proliferation and apoptosis of glioma cells by targeting miR-4677-3p to regulate the expression of MAGI2. In conclusion, our study determined the oncogenic role of GLIDR in glioma, which may provide a new perspective for the treatment of glioma.

LncRNA TTN-AS1 acts as a tumor promoter in gallbladder carcinoma by regulating miR-107/HMGA1 axis

Background

The incidence of gallbladder carcinoma (GBM) in China has increased in recent years. Here, the functional mechanism of lncRNA TTN-AS1 in GBC was preliminary elucidated.

Methods

The expression levels of lncRNA TTN-AS1, miR-107, and HMGA1 in tissues and cell lines were assessed by RT-qPCR. Cell proliferation was measured by MTT assays. Cell invasion and migration abilities were evaluated by Transwell assays. The relationship between miR-107 and lncRNA TTN-AS1 or HMGA1 was confirmed by luciferase reporter assay.

Results

Upregulation of lncRNA TTN-AS1 and downregulation of miR-107 were detected in GBC. Furthermore, the expressions between TTN-AS1 and miR-107 were mutually inhibited in GBC. Functionally, lncRNA TTN-AS1 promoted cell viability and motility in GBC by sponging miR-107. In addition, miR-107 directly targets HMGA1. And HMGA1 can be positively regulated by lncRNA TTN-AS1 in GBC. Furthermore, HMGA1 promoted GBC progression by interacting with lncRNA TTN-AS1/miR-107 axis.

Conclusion

LncRNA TTN-AS1 acted as a tumor promoter in GBC by sponging miR-107 and upregulating HMGA1.

Silencing of the Long Non-Coding RNA TTN-AS1 Attenuates the Malignant Progression of Osteosarcoma Cells by Regulating the miR-16-1-3p/TFAP4 Axis

Objectives

Osteosarcoma (OS) is a type of bone malignancy. This study attempted to explore the effect of long non-coding RNA TTN-AS1 (TTN-AS1) on OS and to determine its molecular mechanisms.

Methods

The expression of TTN-AS1, microRNA-16-1-3p (miR-16-1-3p), and transcription factor activating enhancer binding protein 4 (TFAP4) in OS was assessed using qRT-PCR. The OS cell proliferation, migration, and invasion were measured using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound-healing, and transwell assays. N-cadherin and MMP-2 protein level was determined with western blot. Interactions between TTN-AS1 and miR-16-1-3p or TFAP4 and miR-16-1-3p were confirmed using the dual-luciferase reporter assay. Additionally, an OS xenograft tumor model was constructed to assess the effect of TTN-AS1 on tumor growth.

Results

TTN-AS1 and TFAP4 expression was increased in OS, while miR-16-1-3p expression was decreased. TTN-AS1 silencing restrained OS cell proliferation, migration, invasion, N-cadherin and MMP-2 protein expression, and hindered tumor growth. MiR-16-1-3p overexpression retarded the malignant behavior of OS cells. TTN-AS1 played a carcinostatic role by down-regulating miR-16-1-3p in the OS cells. Moreover, miR-16-1-3p inhibition or TFAP4 elevation weakened the suppressive effect of TTN-AS1 silencing on OS cell tumor progression.

Conclusion

TTN-AS1 promoted the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of OS cells via mediating the miR-16-1-3p/TFAP4 axis. TTN-AS1 may be a critical target for improving OS.

Long Non-Coding RNA LINC00313 Accelerates Cervical Carcinoma Progression by miR-4677-3p/CDK6 Axis

Background

Cervical cancer is one of the most common gynecologic tumors. Evidence is accumulating that long non-coding RNAs participate in the pathogenesis of cancers, but the expression and role of lncRNA LINC00313 in cervical carcinoma is not reported.

Methods

We measured the expression levels of LINC00313 in clinical samples of cervical carcinoma and investigated the function of LINC00313 in the regulation of proliferation, metastasis, and EMT. Luciferase reporter assay was employed to explore the molecular regulation process of LINC00313.

Results

Our data showed that the levels of LINC00313 in cervical carcinoma tissues and cells were significantly up-regulated. Functionally, LINC00313 accelerated the progression, migration, and EMT of SiHa and Hela cells. Luciferase reporter assay confirmed that miR-4677-3p/CDK6 regulatory axis is the direct downstream of LINC00313. Functional gain- and loss-of-function strategies further showed that LINC00313 induced the up-regulation of CDK6 expression through competitive binding with miR-4677-3p, leading to promote the progression of cervical carcinoma.

Conclusion

Our results demonstrated that LINC00313 accelerated the progression of cervical cancer through the miR-4677-3p/CDK6 regulatory axis. LncRNA LINC00313 may serve as a potential target for the diagnosis and treatment of cervical carcinoma.

The LINC00477/miR-128 axis promotes the progression of polycystic ovary syndrome by regulating ovarian granulosa cell proliferation and apoptosis

BACKGROUND

Long noncoding RNAs (lncRNAs) participate in the pathogenesis of various human diseases. This study aims to investigate the roles of lncRNA LINC00477 in polycystic ovary syndrome (PCOS), especially the impacts of LINC00477 on the proliferation and migration of human granulosa cells and the related mechanisms.

METHODS

qRT-PCR analysis was performed to examine the expression pattern of LINC00477 in serum samples of PCOS patients as well as PCOS animal models. The effect of LINC00477 on the viability and apoptosis of ovarian granulosa cells was detected by MTT and flow cytometry assays. The correlation between LINC00477 and miR-128 was verified by bioinformatics analysis and dual-luciferase reporter and RNA pull-down assays. Finally, rescue assays were performed to analyze the effects of the LINC00477-miR-128 axis on the biological behaviors of granulosa cells.

RESULTS

LINC00477 was significantly upregulated in the serum of PCOS patients as well as PCOS mouse models. LINC00477 overexpression inhibited the proliferation and promoted the apoptosis of granulosa cells, whereas knockdown of LINC00477 yielded the opposite effects. Moreover, miR-128 mimics partially abrogated the effect of LINC00477 on granulosa cells.

CONCLUSION

LINC00477 may function as a ceRNA to inhibit proliferation and apoptosis of granulosa cells by modulating miR-128 expression.

TTN-AS1 as a potential diagnostic and prognostic biomarker for multiple cancers

The long noncoding RNAs (lncRNAs) are non-coding RNAs that are more than 200 nucleotides in length, and one of several types of non-coding RNAs (ncRNAs). The lncRNAs function in diverse biological processes in normal cells, such as cellular differentiation and cell cycle regulation. There is also evidence that some aberrantly regulated lncRNAs function as oncogenes or tumor suppressor genes in various cancers. For example, TTN-AS1 is a lncRNA that binds to titin mRNA (TTN) and has pro-oncogenic effects in many cancers. Overexpression of TTN-AS1 correlates with poor prognosis in breast cancer, lung cancer, digestive system neoplasms, reproductive system cancers, and other cancers. Furthermore, increased TTN-AS1 expression correlates with more advanced pathology and tumor malignancy. In this review, we comprehensively summarize recent studies on the molecular mechanisms of TTN-AS1 regulation and the role of TTN-AS1 in the carcinogenesis and progression of numerous tumors.

Overexpression of PAX8-AS1 Inhibits Malignant Phenotypes of Papillary Thyroid Carcinoma Cells via miR-96-5p/PKN2 Axis

BACKGROUND

Thyroid carcinoma (THCA) is the most frequent endocrine malignancy. Papillary thyroid carcinoma (PTC) is the major subtype of THCA, accounting for over 80% of all THCA cases. LncRNA PAX8-AS1, a tumor suppressor associated with various human cancers, has been reported to be relevant to the regulation of all sorts of cellular processes. The purpose of this study was to verify the role of PAX8-AS1 in PTC.

METHODS

Three human PTC cell lines (K1, TPC-1, and IHH4) and one normal human thyroid cell line, Nthy-ori3-1, were used in our study. The expression of genes was detected by qRT-PCR. The bioinformatic analysis and luciferase reporter assay were used to confirm the binding relationship of PAX8-AS1 to miR-96-5p, and the targeting relationship of miR-96-5p to PKN2 was also predicted. Cell proliferation and apoptosis capacities were assessed by MTT and flow cytometry, respectively. EdU assay was used to detect cell proliferation. Western blot assay was employed to examine protein expression.

RESULTS

The expression of PAX8-AS1 was decreased in PTC tissues and cells. PAX8-AS1 overexpression inhibited the proliferation of PTC cells and promoted cell apoptosis. In addition, PAX8-AS1 bonds with miR-96-5p, whose downregulation elevated the expression of PKN2 in PTC cells. Importantly, according to the rescue experiments, PKN2 silencing partially reversed the inhibitory effects of PAX8-AS1 expression on PTC cell proliferation and apoptosis.

CONCLUSIONS

We found that the PAX8-AS1/miR-96-5p/PKN2 axis was closely related to the progression of PTC, which could be a potential target for treating PTC patients.

lncRNA TTN-AS1 facilitates proliferation, invasion, and epithelial-mesenchymal transition of breast cancer cells by regulating miR-139-5p/ZEB1 axis

Breast cancer is a common malignant tumor suffered predominantly by women worldwide, which results in serious levels of morbidity and mortality. To control the effects of the cancer, it is critically important to elucidate the pathophysiological processes by which it occurs and develops. Reports have demonstrated that long noncoding RNAs perform a critical role in the development and metastasis of cancers. The lncRNA TTN-AS1 is considered carcinogenic. Nevertheless, the importance and biological functions of TTN-AS1 in breast cancer require greater exploration. In the current paper, we observed that TTN-AS1 expression was significantly upregulated in breast cancer tissues/cells compared with those that are healthy. TTN-AS1 enhanced the proliferation, migration, invasion, and epithelial-mesenchymal transformation of breast cancer cells. Furthermore, a direct target of TTN-AS1, miR-139-5p was negatively regulated. In addition, zinc finger E-box binding homeobox 1 (ZEB1) is an important nuclear transcription factor, the expression of which is increased in multiple tumors. Here, we also found that ZEB1 is a target of miR-139-5p, of which TTN-AS1 could regulate the expression through competition with miR-139-5p. That is, TTN-AS1 promoted proliferation and invasion of breast cancer cells by interaction with the miR-139-5p/ZEB1 axis. In conclusion, the present study aimed to illustrate the significance of TTN-AS1 in breast cancer metastasis and contribute to potentially innovative strategies for its treatment.

LncRNA BBOX1-AS1 Aggravates the Development of Ovarian Cancer by Sequestering miR-361-3p to Augment PODXL Expression

Ovarian cancer (OC) is a kind of common gynecological malignancy around the world. Mounting literatures have confirmed the implication of lncRNAs in the development of various cancers. Long non-coding RNA (LncRNA) BBOX1-AS1 has not been reported in most cancer types including OC. Presently, we aimed at exploring the function and regulatory mechanism of BBOX1-AS1 in OC. As a result, we demonstrated the extremely high BBOX1-AS1 expression in OC tissues and cells. BBOX1-AS1 silence inhibited OC progression by suppressing cell proliferation and promoting cell apoptosis. Importantly, BBOX1-AS1 was verified to bind to miR-361-3p, which presented a low expression trend in OC cells. Subsequently, PODXL was testified as the downstream target of miR-361-3p. Of note, BBOX1-AS1 positively regulated PODXL through their competition in binding with miR-361-3p. Furthermore, miR-361-3p inhibition facilitated the growth of BBOX1-AS1-deficient OC cells, while such facilitating effect was then counteracted in response to PODXL depletion. All the results above explained that BBOX1-AS1 was overexpressed in OC and that BBOX1-AS1 caused carcinogenic influences on OC cell growth via miR-361-3p/PODXL pathway, highlighting BBOX1-AS1 as a novel potential target for OC treatment.

Circ_0001421 facilitates glycolysis and lung cancer development by regulating miR-4677-3p/CDCA3

BACKGROUND

Lung cancer (LC) is a malignant tumor originating in the bronchial mucosa or gland of the lung. Circular RNAs (circRNAs) are proved to be key regulators of tumor progression. However, the regulatory effect of circ_0001421 on lung cancer tumorigenesis remains unclear.

METHODS

The expression levels of circ_0001421, microRNA-4677-3p (miR-4677-3p) and cell division cycle associated 3 (CDCA3) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Methyl thiazolyl tetrazolium (MTT), Transwell and Tumor formation assays were performed to explore the role of circ_0001421 in LC. Glucose consumption and lactate production were examined by a Glucose assay kit and a Lactic Acid assay kit. Western blot was utilized to examine the protein levels of Hexokinase 2 (HK2) and CDCA3. The interaction between miR-4677-3p and circ_0001421 or CDCA3 was confirmed by dual-luciferase reporter assay.

RESULTS

Circ_0001421 was increased in LC tissues and cells, and knockdown of circ_0001421 repressed cell proliferation, migration, invasion and glycolysis in vitro. Meanwhile, circ_0001421 knockdown inhibited LC tumor growth in vivo. Mechanistically, circ_0001421 could bind to miR-4677-3p, and CDCA3 was a target of miR-4677-3p. Rescue assays manifested that silencing miR-4677-3p or CDCA3 overexpression reversed circ_0001421 knockdown-mediated suppression on cell proliferation, migration, invasion and glycolysis in LC cells.

CONCLUSION

Circ_0001421 promoted cell proliferation, migration, invasion and glycolysis in LC by regulating the miR-4677-3p/CDCA3 axis, which providing a new mechanism for LC tumor progression.

LINC00265 targets miR-382-5p to regulate SAT1, VAV3 and angiogenesis in osteosarcoma

We explored the mechanism by which LINC00265 regulates angiogenesis of osteosarcoma cells via the miR-382-5p/spermidine/spermine N1-acetyltransferase-1 (SAT1) and miR-382-5p/vav guanine nucleotide exchange factor 3 (VAV3) axis. Cell scratch assay, Transwell assay and tube formation assay were applied to detect cell migration, invasion and tube formation abilities. The effects of LINC00265 targeting miR-382-5p in osteosarcoma in vivo were studied using a tumour-burden assay. A total of 70 genes potentially involved in osteosarcoma angiogenesis were identified, and a Gene Ontology (GO) analysis found that SAT1 and VAV3 were closely related to angiogenesis. Bioinformatics analysis and clinical experiments confirmed that LINC00265, SAT1 and VAV3 were overexpressed in osteosarcoma and related to a poor prognosis, whereas miR-382-5p was downregulated and associated with a poor prognosis. It was confirmed that LINC00265 promoted the proliferation, migration, invasion and angiogenesis of osteosarcoma cells by targeting miR-382-5p to mediate SAT1 and VAV3. Collectively, LINC00265 might promote proliferation, migration, invasion and angiogenesis by targeting miR-382-5p/SAT1 and miR-382-5p/VAV3 in osteosarcoma.

Determination of long non-coding RNAs associated with EZH2 in neuroblastoma by RIP-seq, RNA-seq and ChIP-seq

Neuroblastoma (NB) is the most common type of extracranial solid tumor found in children. Despite several treatment options, patients with advanced stage disease have a poor prognosis. Previous studies have reported that enhancer of zeste homolog 2 (EZH2) and long non-coding RNAs (lncRNAs) have abnormal expression levels in NB and participate in tumorigenesis and NB development. However, the association between EZH2 and lncRNAs remain unclear. In the present study, RNA immunoprecipitation-sequencing (RIP-seq) was used to analyze the lncRNAs binding to EZH2. Following EZH2 knockdown via short hairpin RNA, RNA-seq was performed in shEZH2 and control groups in SH-SY5Y cells. Chromatin IP (ChIP)-seq was used to determine the genes that may be regulated by EZH2. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to identify the signaling pathways involved in NB. The results from RIP-seq identified 94 lncRNAs, including SNHG7, SNHG22, KTN-AS1 and Linc00843. Furthermore, results from RNA-seq demonstrated that, following EZH2 knockdown, 448 genes were up- and 571 genes were downregulated, with 32 lncRNAs up- and 35 downregulated and differentially expressed compared with control groups. Certain lncRNAs, including MALAT1, H19, Linc01021 and SNHG5, were differentially expressed in EZH2-knockdown group compared with the control group. ChIP-seq identified EZH2 located in the promoter region of 138 lncRNAs including CASC16, CASC15, LINC00694 and TBX5-AS1. In summary, the present study demonstrated that certain lncRNAs directly bound EZH2 and regulated EZH2 expression levels. A number of these lncRNAs that are associated with EZH2 may participate in NB tumorigenesis.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

LncRNA TTN-AS1 acts as sponge for miR-15b-5p to regulate FBXW7 expression in ovarian cancer

Emerging evidence showed that long noncoding RNA (lncRNA) plays crucial roles in regulating various cancer biological behaviors. Titin-antisense RNA1 (TTN-AS1) has been reported to have crucial roles in cancers but its role in ovarian cancer remains unknown. The levels of TTN-AS1, microNRA-15b-5p (miR-15b-5p), and F-box and WD repeat domain containing 7 (FBXW7) in ovarian cancer cells were measured by quantitative reverse-transcription PCR. Targets for TTN-AS1 and miR-15b-5p were predicted by bioinformatic tools, and validated by luciferase activity reporter assay. Cell proliferation, colony formation, and cell apoptosis were analyzed with cell counting kit-8 assay, colony formation assay, and flow cytometry. Correlation of TTN-AS1 and FBXW7 was analyzed at gene expression profiling interactive analysis. TTN-AS1 was found decreased expression in ovarian cancer tissues and cells. Dual-luciferase activity validated TTN-AS1 and FBXW7 shared binding site in miR-15b-5p. Functional assays showed TTN-AS1 overexpression inhibits ovarian cancer cell proliferation, colony formation but promotes apoptosis. Rescue experiments showed that knockdown of FBXW7 could partially counteracted the effects of TTN-AS1 overexpression on ovarian cancer cell behaviors. Our results indicated that the TTN-AS1/miR-15b-5p/FBXW7 axis identified in this work could help to identify treatment biomarkers for ovarian cancer.

LncRNA TTN-AS1 Promotes Progression of Non-Small Cell Lung Cancer via Regulating miR-491-5p/ZNF503 Axis

Background

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer with high mortality worldwide. Long non-coding RNA (lncRNA) TTN antisense RNA1 (TTN-AS1) has been demonstrated to play a crucial role in a variety of cancers. This study was designed to investigate the function and molecular mechanism of lncRNA TTN-AS1 in NSCLC.

Methods

The expression levels of TTN-AS1, miR-491-5p and zinc finger protein 503 (ZNF503) were examined by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assay, respectively. Cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Cell migration and invasion were assessed by transwell assay. Epithelial-to-mesenchymal transition (EMT)-related proteins were measured using Western blot assay. The relationship between TTN-AS1, miR-491-5p and ZNF503 was predicted by starBase2.0 and confirmed by dual-luciferase reporter assay. Xenograft tumor experiment was conducted to analyze the tumor growth in vivo.

Results

The levels of TTN-AS1 and ZNF503 were up-regulated, while miR-491-5p expression was reduced in NSCLC tissues and cells. Knockdown of TTN-AS1 or ZNF503 suppressed cell proliferation, migration, invasion and EMT in NSCLC cells. Overexpression of ZNF503 reversed the effect of TTN-AS1 silencing on NSCLC progression. TTN-AS1 could modulate the expression of ZNF503 via sponging miR-491-5p. Furthermore, TTN-AS1 induced tumor growth in vivo.

Conclusion

Inhibition of TTN-AS1 hindered cell proliferation, migration, invasion and EMT in NSCLC cells by modulating miR-491-5p/ZNF503 axis, providing a promising biomarker for NSCLC treatment.

Long Non-Coding RNA TTN-AS1 Serves as a Competing Endogenous RNA of miR-195 to Facilitate Clear Cell Renal Cell Carcinoma Progression

Introduction

Clear cell renal cell carcinoma (ccRCC) is an aggressive human malignancy. Long non-coding RNAs (lncRNAs) are critical regulators in many malignant tumors, including ccRCC. The aim of this study is to investigate the expression, functions and molecular mechanisms of lncRNA TTN-AS1 in ccRCC.

Methods

A total of 145 paired cancer and normal tissues were collected from patients with ccRCC. The expression levels of TTN-AS1 and miR-195 in the tissues or cells were measured by RT-qPCR analysis. The expression levels of cyclin D1 protein were measured by Western blot analysis. Cell proliferation and cell cycle distribution were detected by MTT assay and flow cytometer analysis, respectively. The binding relationship between miR-195 and TTN-AS1 or cyclin D1 mRNA was validated by dual-luciferase reporter assay.

Results

Our results revealed that TTN-AS1 expression levels in human ccRCC tissues and cell lines were markedly increased. High expression of TTN-AS1 was closely associated with adverse clinicopathological characteristics of ccRCC patients. Gain- and loss-of-function experiments showed that TTN-AS1 overexpression promoted the proliferation and cell cycle transition of ccRCC cells, while the malignant traits were obviously suppressed after TTN-AS1 knockdown. Mechanistically, miR-195 was found to bind with and to be negatively regulated by TTN-AS1 in ccRCC cells. Further, we showed that cyclin D1 is a direct target of miR-195 in ccRCC, and rescue assays verified that restoration of miR-195 expression partially blocked the oncogenic effects of TTN-AS1 in ccRCC cells.

Conclusion

Our study provides a novel mechanism of TTN-AS1/miR-195/cyclin D1 regulatory axis in ccRCC, which may become a breakthrough for ccRCC therapy in the future.

Long non-coding RNAs: How to regulate the metastasis of non-small-cell lung cancer

Non–small‐cell lung cancer (NSCLC) has become the most lethal human cancer because of the high rate of metastasis. Hence, clarifying the molecular mechanism underlying NSCLC metastasis is very important to improve the prognosis of patients with NSCLC. Long non‐coding RNAs (LncRNAs) are a class of RNA molecules longer than 200 nucleotides, which can participate in diverse biological processes. About 18% of human LncRNAs were recently found to be associated with tumours. Many studies indicated that aberrant expression of LncRNAs played key roles in the progression and metastasis of NSCLC. According to the function in tumours, LncRNAs can be divided into two classes: oncogenic LncRNAs and tumour‐suppressor LncRNAs. In this review, we summarized the main molecular mechanism of LncRNAs regulating NSCLC metastasis, including three aspects: (a) LncRNAs interact with miRNAs as ceRNAs; (b) LncRNAs bind with target proteins; and (c) LncRNAs participate in the transduction of different signal pathways. Then, LncRNAs can exert their function to regulate the metastasis of NSCLC through influencing the progression of epithelial‐mesenchymal transition (EMT) and the properties of cancer stem cell (CSC). But, it is necessary to do some further research to demonstrate the LncRNAs particular regulatory mechanism of inhibiting the metastasis of NSCLC and explore new drugs targeting LncRNAs.

Long non-coding RNA TTN-AS1 promotes tumorigenesis of ovarian cancer through modulating the miR-139-5p/ROCK2 axis

Long non-coding RNA (lncRNA) TTN antisense RNA 1 (TTN-AS1) was reported to be crucial modulators in the tumorigenesis of several types of cancers. However, it is unclear whether TTN-AS1 can regulate the progression of ovarian cancer (OC). The present study aimed to explore functional roles and molecular mechanism of TTN-AS1 in OC. Quantitative reverse transcriptase-polymerase chain reaction assay (qRT-PCR) was used to detect the expression of TTN-AS1 in OC tissues and cell lines. The biological function of TTN-AS1 in OC was identified by a series of in vitro and in vivo assays. Bioinformatics analysis and mechanism experiments were used to analyze and identify the molecular mechanism of TTN-AS1 in OC progression. A high level of TTN-AS1 was found in OC tissues and cell lines. High TTN-AS1 was positively associated with advanced FIGO stage, lymph node metastasis, and poorer overall survival of OC patients. Functionally, knockdown of TTN-AS1 inhibited cell proliferation, colony formation, invasion and migration of OC cells in vitro, and suppressed tumor formation in vivo. Mechanistically, TTN-AS1 functioned as a competing endogenous RNA by sponging microRNA-139-5p (miR-139-5p) to elevate Rho-associated coiled-coil containing protein kinase 2 (ROCK2). Downregulation of miR-139-5p or upregulation of ROCK2 partially rescued the inhibitory impact of TTN-AS1 knockdown on OC cells. These results obtained in the present study suggested that TTN-AS1 promoted the progression of OC by regulating the miR-139-5p/ROCK2 axis.

LncRNA TTN-AS1 sponges miR-376a-3p to promote colorectal cancer progression via upregulating KLF15

AIMS

Long non-coding RNAs (lncRNAs) play key roles in regulating multiple cancers. TTN-AS1 was reported to function in several human malignancies. However, the biological function of TTN-AS1 in colorectal cancer (CRC) has not been explored. In this study, we aimed to investigate the role and the underlying mechanisms of TTN-AS1 in CRC progression.

MAIN METHODS

RT-qPCR was used to detect the expression levels of TTN-AS1, miR-376a-3p and KLF15 in colorectal cancer tissues and cells. CCK-8, colony formation, flow cytometry and transwell assays were performed to determine the cell proliferation, apoptotic rate and invasion ability. Target genes were predicted using bioinformatics methods. si-RNA and miRNA inhibitor were transfected into CRC cells to explore the underlying mechanisms. Tumor xenografts were created to confirm the function of TTN-AS-1 in vivo.

KEY FINDINGS

TTN-AS1 upregulation was observed both in CRC tissues and cell lines. Functional investigation showed that knockdown of TTN-AS1 inhibited CRC cell proliferation and invasion, while enhanced cell apoptosis. Bioinformatics analysis identified miR-376a-3p as a target of TTN-AS1. Transfection of miR-376a-3p inhibitor mitigated the alterations induced by TTN-AS1 knockdown. Moreover, TTN-AS1 positively regulated KLF15 via sponging miR-376a-3p. Additionally, these findings were supported by in vivo experiments.

SIGNIFICANCE

In conclusions, TTN-AS1 promoted CRC proliferation and invasion through miR-376a-3p/KLF15 axis. Our findings suggested that TTN-AS1 might be a potential therapeutic target in CRC treatment.

LINC01419 promotes cell proliferation and metastasis in lung adenocarcinoma via sponging miR-519b-3p to up-regulate RCCD1

Lung adenocarcinoma (LUAD) is one of the most common type of lung cancer notorious for the high incidence and mortality around the world. Long non-coding RNAs (LncRNAs) are defined as a class of RNAs with length more than 200 nucleotides. Mounting studies have proved that lncRNAs are related closely to incidence of diseases and play crucial roles in cancer progression. Although LINC01419 has been studied in several cancers, the function and mechanism of LINC01419 in LUAD remains a mystery. Our findings showed that LINC01419 level was high in LUAD cells, and LINC01419 knockdown inhibited carcinogenesis via suppressing cell proliferation, migration as well as invasion. Moreover, bioinformatics prediction, luciferase reporter experiments and RIP assay were used to confirm miR-519-3p was sequestered and negatively regulated by LINC01419. Subsequently, RCCD1 was identified as a miR-519b-3p target and had inverse relationship with miR-519b-3p. LINC01419 was positively related to RCCD1. Furthermore, rescue assays confirmed that miR-519b-3p inhibitor or RCCD1 overexpression could neutralize the effect of LINC01419 silenced in cell proliferation, migration and invasion. Taken together, all the results indicated that LINC01419 exhibited oncogenic behaviors LUAD via binding to miR-519b-3p to enhance the expression of RCCD1, manifesting the underlying therapy values of LINC01419 in LUAD.

Estimating the Frequency of Single Point Driver Mutations across Common Solid Tumours

For cancers, such as common solid tumours, variants in the genome give a selective growth advantage to certain cells. It has recently been argued that the mean count of coding single nucleotide variants acting as disease-drivers in common solid tumours is frequently small in size, but significantly variable by cancer type (hypermutation is excluded from this study). In this paper we investigate this proposal through the use of integrative machine-learning-based classifiers we have proposed recently for predicting the disease-driver status of single nucleotide variants (SNVs) in the human cancer genome. We find that predicted driver counts are compatible with this proposal, have similar variabilities by cancer type and, to a certain extent, the drivers are identifiable by these machine learning methods. We further discuss predicted driver counts stratified by stage of disease and driver counts in non-coding regions of the cancer genome, in addition to driver-genes.

Long noncoding RNA TTN-AS1 enhances the malignant characteristics of osteosarcoma by acting as a competing endogenous RNA on microRNA-376a thereby upregulating dickkopf-1

The expression levels and detailed functions of TTN-AS1 in osteosarcoma (OS) have not yet been explored. This study aimed to measure TTN-AS1 expression in OS tissues and cell lines, investigate its specific roles in the aggressive characteristics of OS cells in vitro and in vivo, and elucidate the regulatory mechanisms of TTN-AS1 action. TTN-AS1 expression was high in OS tissue samples and cell lines; TTN-AS1 overexpression correlated with the clinical stage, distant metastasis, and shorter overall survival of the patients. A TTN-AS1 knockdown inhibited OS cell proliferation, migration, and invasion and induced apoptosis in vitro and slowed tumor growth in vivo. Mechanism investigation revealed that TTN-AS1 acts as a competing endogenous RNA on microRNA-376a-3p (miR-376a) in OS cells. Dickkopf-1 (DKK1) mRNA was identified as a direct target of miR-376a in OS cells. Resumption of DKK1 expression reversed the tumor-suppressive activities of miR-376a overexpression in OS cells. The knockdown of miR-376a counteracted the reduction in the malignant characteristics of OS cells by the downregulation of TTN-AS1. In conclusion, TTN-AS1 functions as a competing endogenous RNA targeting miR-376a and increases the malignancy of OS cells in vitro and in vivo by upregulating DKK1.