LINC00707 promotes hepatocellular carcinoma progression through activating ERK/JNK/AKT pathway signaling pathway

Non-coding RNA mediated regulation of PI3K/Akt pathway in hepatocellular carcinoma: Therapeutic perspectives

Hepatocellular carcinoma (HCC) is among the primary reasons for fatalities caused by cancer globally, highlighting the need for comprehensive knowledge of its molecular aetiology to develop successful treatment approaches. The PI3K/Akt system is essential in the course of HCC, rendering it an intriguing candidate for treatment. Non-coding RNAs (ncRNAs), such as long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are important mediators of the PI3K/Akt network in HCC. The article delves into the complex regulatory functions of ncRNAs in influencing the PI3K/Akt system in HCC. The study explores how lncRNAs, miRNAs, and circRNAs impact the expression as well as the function of the PI3K/Akt network, either supporting or preventing HCC growth. Additionally, treatment strategies focusing on ncRNAs in HCC are examined, such as antisense oligonucleotide-based methods, RNA interference, and small molecule inhibitor technologies. Emphasizing the necessity of ensuring safety and effectiveness in clinical settings, limitations, and future approaches in using ncRNAs as therapies for HCC are underlined. The present study offers useful insights into the complex regulation system of ncRNAs and the PI3K/Akt cascade in HCC, suggesting possible opportunities for developing innovative treatment approaches to address this lethal tumor.

Linc00707 regulates autophagy and promotes the progression of triple negative breast cancer by activation of PI3K/AKT/mTOR pathway

Triple-negative breast cancer (TNBC) is a pathological subtype of breast cancer (BC) with high malignancy, strong invasiveness and poor prognosis. Long non-coding RNA (LncRNA) plays an important role during tumorigenesis. We identified that Linc00707 was upregulated in TNBC tissues by TCGA database and RT-qPCR assay, compared with normal breast tissues and other subtypes of BC. Linc00707 promoted TNBC cells proliferation, migration and invasion. Furthermore, we found that knockdown of Linc00707 influenced autophagy via PI3K/AKT/mTOR signaling pathway in TNBC cells. Linc00707 affected the progress of TNBC cells through affecting autophagy. Further mechanistic experiments confirmed that Linc00707 could competitively bind with miR-423-5p to up-regulate MARCH2 expression, ultimately promoting TNBC progression and autophagy through PI3K/AKT/mTOR pathway. In conclusion, we demonstrate that Linc00707 is a key molecule in tumor progression and may be an effective target for patients with TNBC.

LINC00707 impairs the Natural Killer cell antitumour activity in hepatocellular carcinoma through decreasing YTHDF2 stability

Hepatocellular carcinoma (HCC) is the fifth most frequently diagnosed cancer and ranks third in cancer-related fatalities. The recognized involvement of long noncoding RNAs (lncRNAs) in several cancer types, including HCC, inspired this study to explore a novel lncRNA's functional importance in the progression of HCC. To achieve this, lncRNA microarray analysis was conducted on three distinct sets of HCC tissues, revealing LINC00707 as the most significantly upregulated lncRNA. Further research into its biological functions has revealed that LINC00707 acts as an oncogene, driving HCC progression by enhancing the proliferation, migration and invasion of HCC cells. Mechanistic insights were provided, demonstrating that LINC00707 interacts with YTH N6-methyladenosine RNA-binding protein 2 (YTHDF2), thus facilitating the ubiquitination-dependent degradation of the YTHDF2 protein. Furthermore, LINC00707 was found to influence the cytotoxicity of NK-92MI cells against HCC cells through its interactions with YTHDF2. These findings significantly contribute to a deeper understanding of the role played by LINC00707 in the progression of HCC.

The long non-coding RNA LINC00707 interacts with Smad proteins to regulate TGFβ signaling and cancer cell invasion

BACKGROUND

Long non-coding RNAs (lncRNAs) regulate cellular processes by interacting with RNAs or proteins. Transforming growth factor β (TGFβ) signaling via Smad proteins regulates gene networks that control diverse biological processes, including cancer cell migration. LncRNAs have emerged as TGFβ targets, yet, their mechanism of action and biological role in cancer remain poorly understood.

METHODS

Whole-genome transcriptomics identified lncRNA genes regulated by TGFβ. Protein kinase inhibitors and RNA-silencing, in combination with cDNA cloning, provided loss- and gain-of-function analyses. Cancer cell-based assays coupled to RNA-immunoprecipitation, chromatin isolation by RNA purification and protein screening sought mechanistic evidence. Functional validation of TGFβ-regulated lncRNAs was based on new transcriptomics and by combining RNAscope with immunohistochemical analysis in tumor tissue.

RESULTS

Transcriptomics of TGFβ signaling responses revealed down-regulation of the predominantly cytoplasmic long intergenic non-protein coding RNA 707 (LINC00707). Expression of LINC00707 required Smad and mitogen-activated protein kinase inputs. By limiting the binding of Krüppel-like factor 6 to the LINC00707 promoter, TGFβ led to LINC00707 repression. Functionally, LINC00707 suppressed cancer cell invasion, as well as key fibrogenic and pro-mesenchymal responses to TGFβ, as also attested by RNA-sequencing analysis. LINC00707 also suppressed Smad-dependent signaling. Mechanistically, LINC00707 interacted with and retained Smad proteins in the cytoplasm. Upon TGFβ stimulation, LINC00707 dissociated from the Smad complex, which allowed Smad accumulation in the nucleus. In vivo, LINC00707 expression was negatively correlated with Smad2 activation in tumor tissues.

CONCLUSIONS

LINC00707 interacts with Smad proteins and limits the output of TGFβ signaling, which decreases LINC00707 expression, thus favoring cancer cell invasion. Video Abstract.

Decoding hepatocarcinogenesis from a noncoding RNAs perspective

Being a leading lethal malignancy worldwide, the pathophysiology of hepatocellular carcinoma (HCC) has gained a lot of interest. Yet, underlying mechanistic basis of the liver tumorigenesis is poorly understood. The role of some coding genes and their respective translated proteins, then later on, some noncoding RNAs (ncRNAs) such as microRNAs have been extensively studied in context of HCC pathophysiology; however, the implication of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in HCC is indeed less investigated. As a subclass of the ncRNAs which has been elusive for long time ago, lncRNAs was found to be involved in plentiful cellular functions such as DNA, RNA, and proteins regulation. Hence, it is undisputed that lncRNAs dysregulation profoundly contributes to HCC via diverse etiologies. Accordingly, lncRNAs represent a hot research topic that requires prime focus in HCC. In this review, the authors discuss breakthrough discoveries involving lncRNAs and circRNAs dysregulation that have contributed to the contemporary concepts of HCC pathophysiology and how these concepts could be leveraged as potential novel diagnostic and prognostic HCC biomarkers. Further, this review article sheds light on future trends, thereby discussing the pathological roles of lncRNAs and circRNAs in HCC proliferation, migration, and epithelial-to-mesenchymal transition. Along this line of reasoning, future recommendations of how these targets could be exploited to achieve effective HCC-related drug development is highlighted.

RNA-binding protein CCDC137 activates AKT signaling and promotes hepatocellular carcinoma through a novel non-canonical role of DGCR8 in mRNA localization

BACKGROUND

RNA binding proteins (RBPs)-regulated gene expression play a vital role in various pathological processes, including the progression of cancer. However, the role of RBP in hepatocellular carcinoma (HCC) remains much unknown. In this study, we aimed to explore the contribution of RBP CCDC137 in HCC development.

METHODS

We analyzed the altered expression level and clinical significance of CCDC137 in database and HCC specimens. In vitro cell assays and in vivo spontaneous mouse models were used to assess the function of CCDC137. Finally, the molecular mechanisms of how CCDC137 regulates gene expression and promotes HCC was explored.

RESULTS

CCDC137 is aberrantly upregulated in HCC and correlates with poor clinical outcomes in HCC patients. CCDC137 markedly promoted HCC proliferation and progression in vitro and in vivo. Mechanistically, CCDC137 binds with FOXM1, JTV1, LASP1 and FLOT2 mRNAs, which was revealed by APOBEC1-mediated profiling, to increase their cytoplasmic localization and thus enhance their protein expressions. Upregulation of FOXM1, JTV1, LASP1 and FLOT2 subsequently synergistically activate AKT signaling and promote HCC. Interestingly, we found that CCDC137 binds with the microprocessor protein DGCR8 and DGCR8 has a novel non-canonical function in mRNA subcellular localization, which mediates the cytoplasmic distribution of mRNAs regulated by CCDC137.

CONCLUSIONS

Our results identify a critical proliferation-related role of CCDC137 and reveal a novel CCDC137/DGCR8/mRNA localization/AKT axis in HCC progression, which provide a potential target for HCC therapy.

Targeting Extracellular Signal-Regulated Protein Kinase 1/2 (ERK1/2) in Cancer: An Update on Pharmacological Small-Molecule Inhibitors

Extracellular signal-regulated protein kinase 1/2 (ERK1/2), the only known substrate of MEK1/2, is located downstream of the RAS-RAF-MEK-ERK (MAPK) pathway and is associated with the abnormal activation and poor prognosis of cancer. To date, several small-molecule inhibitors of RAS, RAF, and MEK have been reported to make rapid advances in cancer therapy; however, acquired resistance still occurs, thereby weakening the therapeutic efficacy of these inhibitors. Recently, selective inhibition of ERK1/2 has been regarded as a potential cancer therapeutic strategy that can not only effectively block the MAPK pathway but also overcome drug resistance caused by upstream mutations in RAS, RAF, and MEK. Herein, we summarize the oncogenic roles, key signaling network, and the single- and dual-target inhibitors of ERK1/2 in preclinical and clinical trials. Together, these inspiring findings shed new light on the discovery of more small-molecule inhibitors of ERK1/2 as candidate drugs to improve cancer therapeutics.

LncRNA LINC00707 serves as a sponge of miR-382-5p to alleviate lipopolysaccharide (LPS)-induced WI-38 cell injury through upregulating NKAP in infantile pneumonia

Infantile pneumonia (IP) is an acute lower respiratory infection that imposes a heavy burden on children's health. Increasing evidence has demonstrated that long non-coding RNA (lncRNA) LINC00707 participates in the regulation of the pneumonia process. Cell proliferative ability and apoptosis were measured using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays. Bcl-2 related X protein (Bax), NF-kB activating protein (NKAP), p-P65, P65, p-IκBα, and IκBα protein levels were detected using western blot assay. The binding between miR-382-5p and LINC00707 or NKAP was predicted by starBase v2.0 and then verified by a dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. LINC00707 and NKAP levels were increased, and miR-382-5p was decreased in LPS-stimulated WI-38 cells. Furthermore, the silencing of LINC00707 could abrogate LPS-engendered WI-38 cell proliferation, apoptosis, and oxidative stress. LINC00707 deficiency could relieve LPS-triggered WI-38 cell damage by regulating the miR-382-5p/NKAP axis, providing a new therapeutic strategy for IP treatment.

LINC00707 knockdown inhibits IL-1β-induced apoptosis and extracellular matrix degradation of osteoarthritis chondrocytes by the miR-330-5p/FSHR axis

BACKGROUND

Osteoarthritis (OA) is a severe disabling condition that causes major health problems. The roles of lncRNAs in regulating OA progression have been increasingly researched. Based on previously published microarray analysis, LINC00707 is upregulated in OA. This research was done to uncover the function of LINC00707 in IL-1β-induced chondrocyte injury and its possible mechanisms.

METHODS

LINC00707, miR-330-5p, and FSHR expression in OA cartilage tissues were assessed by RT-qPCR. Primary chondrocytes were isolated from OA tissues and treated with IL-1β to establish an in vitro OA model. Under the indicated treatment, chondrocyte apoptosis, senescence, ECM degradation, and inflammation were determined using flow cytometry, TUNEL, SA-β-Gal staining, and ELISA experiments, respectively. Interactions between gene were evaluated using Ago2 RIP and luciferase reporter assays.

RESULTS

LINC00707 and FSHR were elevated, and miR-330-5p was reduced in cartilage tissues of OA patients and in IL-1β-treated primary chondrocytes. Silencing LINC00707 hampered chondrocytes apoptosis, senescence, ECM degradation, and inflammation. LINC00707 acted as a ceRNA to regulate FSHR through controlling miR-330-5p availability. Additionally, both miR-330-5p depletion and FSHR overexpression diminished the effects of silencing LINC00707 in OA progression.

CONCLUSION

Silencing LINC00707 mitigates chondrocyte injury in osteoarthritis via sponging miR-330-5p and inhibiting FSHR.

Review of LINC00707: A Novel LncRNA and Promising Biomarker for Human Diseases

Long noncoding RNAs (lncRNAs) are a major type of noncoding RNA greater than 200 nucleotides in length involved in important regulatory processes. Abnormal expression of certain lncRNAs contributes to the pathogenesis of multiple diseases, including cancers. The lncRNA LINC00707 is located on chromosome 10p14 and is abnormally expressed in numerous disease types, and particularly in several types of cancer. High LINC00707 levels mediate a series of biological functions, including cell proliferation, apoptosis, metastasis, invasion, cell cycle arrest, inflammation, and even osteogenic differentiation. In this review, we discuss the main functions and underlying mechanisms of LINC00707 in different diseases and describe promising applications of LINC00707 in clinical settings.

Long Noncoding RNA LINC00707 Accelerates Tumorigenesis and Progression of Bladder Cancer via Targeting miR-145/CDCA3 Regulatory Loop

INTRODUCTION

Growing studies reveal that long noncoding RNA is involved in oncogenesis and progression. Previous studies have demonstrated that long intergenic noncoding RNA 00707 (LINC00707) stimulated tumor progress in numerous neoplasm types; however, the function of LINC00707 in bladder cancer (BC) was not yet clear. Our researches aimed to determine whether LINC00707 was dysregulated in BC and further study its biological functions.

METHODS

LINC00707 levels in BC tissues and cells were measured using reverse transcription-PCR (RT-PCR), and the associations between the levels of LINC00707 and clinicopathological features and the months of survival were also examined. Then, Cell Counting Kit-8 assays, flow cytometry, colony formation assays, and Transwell assays were applied for the assessment of the impact of LINC00707 on the abilities of BC cells. The interaction between LINC00707 and miR-145 or cell division cycle associated 3 was determined by luciferase reporter system and RT-PCR. Protein expressions of Wnt/β-catenin signaling were examined using RT-PCR and Western blot.

RESULTS

We found that LINC00707 expressions were notably upregulated in BC samples and cells. Higher expressions of LINC00707 were associated with T stage, grade, and shorter overall survival in BC patients. LINC00707 was also an independent prognostic factor for BC. In vitro assays confirmed that silencing LINC00707 expressions suppressed cell proliferation, colony formation, and metastasis. Mechanistic studies elucidated that LINC00707 was directly targeted to miR-145/CDCA3. Western blot assays revealed that Wnt/β-catenin signaling was inactivated by LINC00707 knockdown.

CONCLUSION

Our work offers new insight into the function of LINC00707 in the tumorigenesis of BC.

Interaction between non-coding RNAs and JNK in human disorders

Jun N-terminal Kinase (JNK) signaling pathway is a conserved cascade among species with particular roles in diverse processes during embryogenesis and normal life. These kinases regulate functions of neurons and the immune system by affecting the expression of genes, modulating the arrangement of cytoskeletal proteins, and regulating apoptosis/survival pathways. They are also involved in carcinogenesis. Several miRNAs and lncRNAs have a functional relationship with JNKs. This interaction contributes to the pathogenesis of traumatic brain injury, ulcerative colitis, hepatic ischemia/ reperfusion injury, acute myocardial infarction, and a number of other disorders. Lung cancer, hepatocellular carcinoma, gall bladder cancer, melanoma, and colon cancer are among malignant conditions in which JNK-related miRNAs/ lncRNAs contribute. The current review aims at depicting the functional interaction between JNKs and lncRNAs/ miRNAs and describing the role of these regulatory transcripts in the pathobiology of human disorders.

HNRNPD interacts with ZHX2 regulating the vasculogenic mimicry formation of glioma cells via linc00707/miR-651-3p/SP2 axis

Studies have found that RNA-binding proteins (RBPs) are dysfunctional and play a significant regulatory role in the development of glioma. Based on The Cancer Genome Atlas database and the previous studies, we selected heterogeneous nuclear ribonucleoprotein (HNRNPD) as the research candidate and sought its downstream targeted genes. In the present study, HNRNPD, linc00707, and specific protein 2 (SP2) were highly expressed, while zinc fingers and homeboxes 2 (ZHX2) and miR-651-3p were remarkedly downregulated in glioma tissues and cells. HNRNPD, linc00707, and SP2 knockdown or ZHX2 and miR-651-3p overexpression suppressed glioma cells proliferation, migration, and invasion and vasculogenic mimicry (VM) formation. Knockdown of HNRNPD increased the stability of ZHX2 mRNA. ZHX2 bound to the promoter region of linc00707 and negatively regulate its expression. Linc00707 could bind with miR-651-3p, while miR-651-3p bound to the 3' untranslated region (3'UTR) of SP2 mRNA to negatively regulate its expression. The transcription factor SP2 directly bound to the promoter regions of the VM formation-related proteins MMP2, MMP9, and VE-cadherin, playing a role in promoting transcription in order to regulate the VM formation ability of glioma cells.

The Long Intergenic Noncoding RNA 00707 Sponges MicroRNA-613 (miR-613) to Promote Proliferation and Invasion of Gliomas

Background:

Glioma is one of the most deadly malignant tumors in humans. Long non-coding RNA (lncRNA) plays a key role in the occurrence, development and invasion of tumors by regulating oncogenic and tumor suppressor pathways. However, the role and action mechanism of long intergenic non-coding RNA 00707 (LINC00707) in gliomas have not been elucidated. This study aimed to investigate the interaction between LINC00707 and miR-613 as well as its role in gliomas.

Materials and Methods:

The expression levels of LINC00707 and miR-613 were detected by qRT-PCR. The chi-square test was used to analyze the correlation between LINC00707 expression and clinicopathological parameters. CCK-8 and colony formation assays were used to detect glioma cell proliferation; and wound healing and transwell assays were used to detect glioma cell migration and invasion. The relationship between LINC00707 and miR-613 was predicted by Starbase, and verified by qRT-PCR and dual luciferase reporter gene assay.

Results:

LINC00707 was up-regulated in gliomas. Up-regulated LINC00707 increased the proliferation, migration and invasion of glioma cells, and silenced LINC00707 reduced these abilities. The increase of the expression level of LINC00707 down-regulated miR-613 in glioma cells, while the inhibition of the expression level of LINC00707 up-regulated miR-613 in glioma cells. The high expression of LINC00707 was related to the Karnofsky performance status (KPS) score and WHO staging. LINC00707 could offset the ability of miR-613 to inhibit glioma proliferation and invasion.

Conclusion:

LINC00707 promotes proliferation and invasion of glioma cells by sponging miR-613. The regulatory axis of LINC00707/miR-613 provides new insights into the mechanism and treatment of gliomas.

PI3K/AKT/mTOR pathway-related long non-coding RNAs: roles and mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide with high prevalence and lethality. The oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a classic dysregulated pathway involved in the pathogenesis of HCC. However, the underlying mechanism for how PI3K/AKT/mTOR pathway aberrantly activates HCC has not been entirely elucidated. The recognition of the functional roles of long non-coding RNAs (lncRNAs) in PI3K/AKT/mTOR signaling axis sheds light on a new dimension to our understanding of hepatocarcinogenesis. In this review, we comprehensively summarize 67 dysregulated PI3K/AKT/mTOR pathway-related lncRNAs in HCC. Many studies have indicated that the 67 dysregulated lncRNAs show oncogenic or anti-oncogenic effects in HCC by regulation on epigenetic, transcriptional and post-transcriptional levels and they play pivotal roles in the initiation of HCC in diverse biological processes like proliferation, metastasis, drug resistance, radio-resistance, energy metabolism, autophagy and so on. Besides, many of these lncRNAs are associated with clinicopathological features and clinical prognosis in HCC, which may provide a potential future application in the diagnosis and therapy of HCC.

Long Noncoding RNAs Coregulated by Annexin A7 and JNK in Hepatocellular Carcinoma Cells Identified by Whole-Genome Expression Profiling

Knockdown of Annexin A7 (ANXA7) or C-Jun N-terminal kinase (JNK) inhibits the proliferation, migration, invasion, and lymphatic adhesion of hepatocellular carcinoma (HCC) cells, suggesting that ANXA7 and JNK signaling pathways contribute to HCC growth and lymph node metastasis (LNM). While the intervening molecular pathways are largely unknown, emerging evidence suggests that long noncoding RNAs (lncRNAs) participate in ANXA7 and JNK signaling. To identify potential therapeutic targets for HCC, we screened for lncRNAs differentially expressed among Hca-P cells stably expressing shRNA-ANXA7, shRNA-JNK, or control-shRNA. RNA sequencing identified 216 lncRNAs differentially expressed between shRNA-ANXA7 and control-shRNA cells, of which 101 were downregulated and 115 upregulated, as well as 436 lncRNAs differentially expressed between shRNA-JNK and control-shRNA cells, of which 236 were downregulated and 200 upregulated. Fifty-six lncRNAs were differentially expressed under both ANXA7 and JNK knockdown. We selected 4 of these for verification based on putative involvement in cancer regulation according to GO and KEEG analyses of target genes. Knockdown of ANXA7 or JNK suppressed expression of NONMMUT012084.2, NONMMUT024756.2, and ENSMUST00000130486, and enhanced expression of ENSMUST00000197932. These lncRNAs are intriguing candidate targets for mechanistic analysis of HCC progression and therapeutic intervention.

The Long Noncoding RNA ZFAS1 Potentiates the Development of Hepatocellular Carcinoma via the microRNA-624/MDK/ERK/JNK/P38 Signaling Pathway

Background

A long noncoding RNA (lncRNA), ZNFX1 antisense RNA 1 (ZFAS1), was increased in multiple cancers, including hepatocellular carcinoma (HCC), resulting in malignancy development and progression. However, the mechanisms involving the interaction between ZFAS1 and microRNA-624 (miRNA-624) remain largely unknown. Therefore, the goal of this study was to probe the functional role of ZFAS1 in the development of HCC and its underlying mechanism.

Methods

Firstly, differentially expressed lncRNAs in HCC tissues were screened out by microarray. Subsequently, the prognostic effect of ZFAS1 patients with HCC was analyzed by the Kaplan-Meier analysis and The Cancer Genome Atlas database. ZFAS1 regulation on miRNA-624 was determined after si-ZFAS1 and/or miRNA-624 inhibitor were transfected into HepG2 and SMMC7721 cell lines. Finally, the effects of ZFAS1 on the growth and metastasis of HCC were observed by in vivo tumorigenesis and metastasis tests.

Results

ZFAS1 was overexpressed in HCC tissues and cells and indicated worse prognosis and shorter survival in patients with HCC. Silencing of ZFAS1 inhibited the malignancy of HCC cells, but miR-624 inhibitor could partially reverse the repressive role of si-ZFAS1. Moreover, ZFAS1 induced the extracellular-regulated protein kinases/c-Jun N-terminal kinase (ERK/JNK)/P38 pathway by binding to midkine (MDK) through miR-624, thus promoting the occurrence of HCC.

Conclusion

Collectively, ZFAS1 depletion inhibited the occurrence of HCC by downregulating the MDK/ERK/JNK/P38 pathway through restoring miR-624 expression. Inhibition of ZFAS1 may act as an innovative target to suppress occurrence in HCC.

Long non-coding RNA LINC00707 acts as a competing endogenous RNA to enhance cell proliferation in colorectal cancer

Long non-coding RNAs (lncRNAs) have been indicated to serve critical roles in cancer development and progression. Long intergenic non-protein coding RNA 70 (LINC00707) was recently reported to be an oncogene involved in the tumorigenesis of several types of human cancer. However, the clinical role, biological functions and molecular mechanism of LINC00707 in colorectal cancer (CRC) remain unclear. The aim of the present study was to investigate the biological effects and mechanism of LINC00707 in CRC. Reverse transcription-quantitative PCR was used to detect the expression levels of LINC00707 in 65 CRC tissue samples and CRC cell lines (HCT116, HT29 and SW480). Cell Counting Kit-8 and colony formation assays were performed to investigate the effects of LINC00707 on CRC cell proliferation. A dual-luciferase reporter assay was conducted to investigate the mechanisms of LINC00707 in CRC. The upregulation of LINC00707 expression was significantly associated with tumor size, stage and poor survival in patients with CRC. LINC00707 also acted as an independent prognostic factor for CRC. Functional analyses revealed that the knockdown of LINC00707 could inhibit CRC cell proliferation. Furthermore, bioinformatics analysis demonstrated that microRNA (miR)-485-5p could directly bind to LINC00707, which was confirmed by a dual-luciferase reporter assay. In conclusion, the upregulation of LINC00707 is associated with a shorter survival time in patients with CRC. Knockdown of LINC00707 may inhibit the proliferation of CRC cells by binding with miR-485-5p.

Long Noncoding RNA RP5-833A20.1 Suppresses Tumorigenesis In Hepatocellular Carcinoma Through Akt/ERK Pathway By Targeting miR-18a-5p

Background

Previous studies indicated that long noncoding RNAs (lncRNAs) played vital roles in the development and progression of hepatocellular carcinoma (HCC). Recently, downregulation of lncRNA RP5‑833A20.1 has been observed in HCC tissues. However, the underlying mechanism by which RP5‑833A20.1 regulates the proliferation and apoptosis in HCC has not been investigated. Thus, this study aimed to investigate the role of RP5‑833A20.1 in the progression of HCC.

Methods

The levels of RP5‑833A20.1 in 30 pairs of HCC tissues and adjacent normal tissues were detected by RT-qPCR. In addition, the effects of RP5‑833A20.1 on cell proliferation, apoptosis and invasion were evaluated by CCK-8, flow cytometric, transwell assays, respectively. Meanwhile, the dual-luciferase reporter system assay was used to explore the interaction of RP5‑833A20.1 and miR-18a-5p in HCC.

Results

The level of RP5‑833A20.1 was significantly downregulated in HCC tissues and HCC cell lines. Downregulation of RP5‑833A20.1 markedly promoted the proliferation and invasion of Bel-7402 cells. In addition, overexpression of RP5‑833A20.1 notably inhibited the proliferation and invasion of Huh7 cells. Moreover, overexpression of RP5‑833A20.1 obviously induced the apoptosis of Huh7 cells via increasing the levels of Bax and active caspase 3, and decreasing the levels of Bcl-2, p-Akt and p-ERK. Meanwhile, in vivo experiments performed also indicated that overexpression of RP5-833A20.1 could inhibit the tumorigenesis of subcutaneous Huh7 xenograft in nude mice. Furthermore, bioinformatics and luciferase reporter assay identified that RP5-833A20.1 functioned as a competing endogenous RNA (ceRNA) for miR-18a-5p in HCC.

Conclusion

In this study, we found that RP5‑833A20.1 was downregulated in HCC tissues. In addition, RP5-833A20.1 could suppress the tumorigenesis in HCC through inhibiting Akt/ERK pathway by acting as a ceRNA for miR-18a-5p. Therefore, RP5-833A20.1 might be a valuable and potential biomarker and therapeutic target for the treatment of HCC.

Silencing long intergenic non-coding RNA 00707 enhances cisplatin sensitivity in cisplatin-resistant non-small-cell lung cancer cells by sponging miR-145

The aberrant expression of long non-coding RNAs is closely associated with drug resistance in multiple types of cancer. Long intergenic non-coding RNA 00707 (LINC00707) has previously been reported to be an oncogene able to promote lung adenocarcinoma cell proliferation and metastasis. However, its role in the progression of cisplatin (DDP) resistance in non-small-cell lung cancer (NSCLC) requires further elucidation. In the present study, LINC00707 and microRNA (miR)-145 expression levels were measured using reverse transcription-quantitative PCR (RT-qPCR). MTT and flow cytometric assays were performed to evaluate the IC₅₀ value of DDP and cell apoptosis, respectively. Bcl-2, Bax, multidrug resistance protein 1 (MRP1) and P-glycoprotein (P-gp) mRNA and protein expression were detected using RT-qPCR and western blotting, respectively. The interaction between LINC00707 and miR-145 was explored using a luciferase reporter assay. LINC00707 expression was found to be significantly upregulated in DDP-resistant A549 cells (A549/DDP) cells when compared with that in parental A549 cells. LINC00707 knockdown reduced the IC₅₀ value of DDP, enhanced apoptosis and inhibited Bcl-2, MRP1 and P-gp expression, while promoting Bax expression in A549/DDP cells. miR-145 expression was found to be significantly decreased in A549/DDP cells when compared with in A549 cells. LINC00707 directly interacted with miR-145 and negatively regulated its expression. Furthermore, miR-145 downregulation weakened the effect of LINC00707 knockdown in A549/DDP cells. Therefore, silencing of LINC00707 enhanced DDP sensitivity in A549/DDP cells by sponging miR-145, thereby shedding light on LINC00707 and its corresponding molecular mechanisms involved in the progression of DDP resistance in NSCLC cells.

MicroRNA-876 is sponged by long noncoding RNA LINC00707 and directly targets metadherin to inhibit breast cancer malignancy

Background: MicroRNA-876-5p (miR-876) dysregulation contributes to the aggressiveness of various types of human cancer. This study was aimed at measuring miR-876 expression in breast cancer, determining the specific roles of miR-876 in the progression of breast cancer and understanding the corresponding molecular mechanisms.

Materials and methods: miR-876 expression in breast cancer tissues and cell lines was quantified via RT-qPCR. The effect of miR-876 upregulation on the malignant phenotype of breast cancer cells was investigated using CCK-8 assays, flow cytometry, Transwell migration and invasion assays and tumor xenograft experiments. The mechanisms underlying the tumor-suppressive action of miR-876 in breast cancer cells were explored using bioinformatic analysis, luciferase reporter assays, RT-qPCR and Western blot analysis.

Results: miR-876 was found to be underexpressed in breast cancer tissues and cell lines. Decreased miR-876 expression notably correlated with lymphatic invasion metastasis, TNM stage and differentiation grade. Overall survival was lower among patients with breast cancer and low miR-876 expression than in patients with high miR-876 expression. Restoration of miR-876 expression decreased breast cancer cell proliferation, migration and invasion in vitro and restricted tumor growth in vivo as well as increased cell apoptosis. Metadherin (MTDH) was identified as a novel target of miR-876 in breast cancer cells. Furthermore, long intergenic nonprotein-coding RNA 707 (LINC00707) acted as a molecular sponge for miR-876, thereby regulating MTDH expression in breast cancer. Finally, silencing miR-876 expression attenuated the influence of a LINC00707 knockdown on the malignancy of breast cancer cells.

Conclusion: This study, thus, revealed the vital functions of the LINC00707–miR-876–MTDH pathway in breast cancer and provided attractive targets and markers for its treatment.

Long intergenic noncoding RNA 00707 promotes colorectal cancer cell proliferation and metastasis by sponging miR-206

Background: The incidence and mortality of colorectal cancer (CRC) are rising worldwide. Long-noncoding RNAs (lncRNAs) are known to play key roles in the development of human cancers, including CRC. However, the function and underlying mechanism of long intergenic noncoding RNA 00707 (LINC00707) in the development of CRC are unknown.

Materials and methods: The expression of LINC00707 and miR-206 in tissue samples or cell lines was measured by quantitative reverse transcription PCR (qRT-PCR). The protein expression of neurogenic locus notch homolog protein 3 (NOTCH3) and transmembrane 4 L6 family member 1 (TM4SF1) was assessed by Western blotting. Cell proliferation, migration, and invasion were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and transwell assays. Luciferase reporter assay and biotin-coupled miRNA capture assay were used to explore the relationship between LINC00707 and miR-206 expression.

Results: The expression of LINC00707 was significantly upregulated in CRC tissues as compared with the adjacent non-CRC tissues. LINC00707 expression was significantly correlated with tumor size, lymphatic metastasis, and distant metastasis, but not significantly correlated with age and gender. Knockdown of LINC00707 expression significantly inhibited LoVo and HCT116 cell proliferation, migration, and invasion. LINC00707 acted as a molecular sponge by competing for miR-206 and indirectly modulating the expression of its targets, NOTCH3 and TM4SF1.

Conclusion: LINC00707 promotes CRC cell proliferation and metastasis by sponging miR-206, suggestive of its potential application for CRC treatment.

LncRNA LOC105372579 promotes proliferation and epithelial-mesenchymal transition in hepatocellular carcinoma via activating miR-4316/FOXP4 signaling

Background: Recently, a growing number of long noncoding RNAs (lncRNAs) have been identified to be important for human cancer development. However, how lncRNA regulates hepatocellular carcinoma (HCC) progression still remains largely unclear. We aimed to investigate the function of LOC105372579 in HCC progression. Materials and methods: The expression levels of lncRNA LOC105372579 in HCC tissues and cell lines were analyzed by qRT-PCR. The effects of LOC105372579 silencing on proliferation, migration and invasion were determined by using cell counting kit-8, colony formation assay and Transwell assay. Moreover, the xenograft mouse model was used to detect how LOC105372579 regulates HCC growth in vivo. Results: LOC105372579 was highly expressed in HCC tissues and cell lines. Moreover, upregulated levels of LOC105372579 predicted poor prognosis. LOC105372579 silencing suppressed the proliferation of HCC cells in vitro. We also validated that LOC105372579 knockdown inhibited the migration, invasion, and epithelial-mesenchymal transition of HCC cells. Xenograft assay demonstrated that LOC105372579 promotes tumor growth in vivo. Mechanistically, we identified that LOC105372579 is a sponge for miR-4316 and that FOXP4 is a direct target of miR-4316. Conclusion: Thus, our findings supported that LOC105372579 contributes to HCC cell proliferation, migration, invasion, and EMT by activating miR-4316/FOXP4 signaling.