Regulatory mechanism of lncRNA NORAD on proliferation and invasion of ovarian cancer cells through miR-199a-3p

MiR-199a-3p Overexpression Suppressed Cell Proliferation and Sensitized Chronic Myeloid Leukaemia Cells to Imatinib by Inhibiting mTOR Signalling

INTRODUCTION

Chronic myeloid leukaemia (CML) is a myeloproliferative neoplasm characterized by constitutive activity of the tyrosine kinase BCR-ABL1. Drug resistance remains one of the major challenges in CML therapy. MicroRNA (miR)-199a-3p plays an important role in many tumours but has rarely been investigated in CML. We aimed to analyse the role and mechanism of miR-199a-3p in regulating imatinib resistance in CML.

METHODS

The expression of miR-199a-3p and mammalian target of rapamycin (mTOR) in the serum of CML patients and CML cells was examined by quantitative real-time polymerase chain reaction. The levels of apoptosis-related proteins were determined using western blot. The relative cell survival rate and cell proliferation were determined using a CCK-8 assay and a bromodeoxyuridine (BrdU) assay, respectively. Cell cycle and apoptosis were analysed using flow cytometry. Moreover, a dual-luciferase reporter assay was performed to verify the correlation between miR-199a-3p and mTOR.

RESULTS

MiR-199a-3p was downregulated in the serum of CML patients and in CML cells, while mTOR was upregulated. Both miR-199a-3p overexpression and mTOR silencing inhibited CML cell proliferation, promoted CML cell apoptosis, and sensitized these cells to imatinib. mTOR silencing reversed the promoting effect of miR-199a-3p inhibition on the proliferation of CML cells and the inhibitory effects on cell apoptosis and sensitivity to imatinib. MiR-199a-3p directly targeted mTOR.

CONCLUSION

MiR-199a-3p suppressed cell propagation, facilitated apoptosis of CML cells, and sensitized CML cells to imatinib by downregulating mTOR signalling.

Suppression of lncRNA NORAD may affect cell migration and apoptosis in gastric cancer cells

BACKGROUND

Gastric cancer (GC) is a major malignancy that threatens people's lives worldwide. Long noncoding RNA (lncRNA) non-coding RNA activated by DNA damage (NORAD) is known to be a potential oncogene in many cancers and may promote cell migration and metastasis, and decrease apoptosis rate.

MATERIAL AND METHODS

NORAD expression was measured in 70 pairs of GC tissues and their adjacent normal tissues (ANTs) by quantitative real-time polymerase chain reaction. Si-NORAD gene knockdown study and cellular assays were conducted to assess the correlation between NORAD expression and cell viability, apoptosis, migration, and metastasis.

RESULTS

NORAD was significantly overexpressed in GC tissues compared to ANTs (P value < 0.0001). The receiver operating characteristic curve indicated the AUC of 0.721 with the sensitivity and specificity of 78.57 and 61.43, respectively (P value < 0.0001). NORAD downregulation leads to decreased cell viability (P value < 0.001) and migration (P value < 0.01), increased apoptosis rate (P value < 0.0001), and increased protein level for PTEN, E-cadherin, and Bax, but decreased protein level for Bcl-2.

CONCLUSION

Generally, NORAD may serve as a potential diagnostic biomarker in GC.

Long non-coding RNA NORAD induces phenotypic regulation of vascular smooth muscle cells through regulating microRNA-136-5p-targeted KDM1A

OBJECTIVE

Effect of long non-coding RNAs (lncRNAs) on intracranial aneurysm (IA) development has been identified, while the role of noncoding RNA activated by DNA damage (NORAD) in IA remains unexplored. We aimed to verify the impact of NORAD on IA through sponging microRNA-136-5p (miR-136-5p).

METHODS

Ruptured and unruptured IAs were harvested from IA patients, and expression of NORAD, miR-136-5p, and KDM1A was determined. The vascular smooth muscle cells (VSMCs) were cultured and, respectively, transfected with altered NORAD, miR-136-5p, or lysine-specific demethylase 1 (KDM1A) to observe their effect on biological functions, as well as on contraction and synthesis-specific indices of VSMCs. Interactions between NORAD and miR-136-5p, and between miR-136-5p and KDM1A were confirmed.

RESULTS

NORAD and KDM1A were upregulated while miR-136-5p was downregulated in IA, especially in ruptured IA. NORAD overexpression or miR-136-5p inhibition accelerated proliferation and migration, and decelerated phenotypic switching and apoptosis of VSMCs. The effects of overexpressed NORAD on VSMCs were reserved by miR-136-5p upregulation or KDM1A knockdown. NORAD functioned as a competing endogenous RNA of miR-136-5p and miR-136-5p targeted KDM1A.

CONCLUSION

NORAD suppressed miR-136-5p, thus upregulating KDM1A to participate in IA formation and rupture by inducing phenotypic regulation of VSMCs.

LncRNA RP11-499E18.1 Inhibits Proliferation, Migration, and Epithelial-Mesenchymal Transition Process of Ovarian Cancer Cells by Dissociating PAK2-SOX2 Interaction

Background: Ovarian cancer (OC)is a deadly gynecological malignancy worldwide. It is urgent to identify diagnostic biomarkers of OC to disclose the underlying mechanism. Methods and Materials: Bioinformatics analysis was used to identify target genes. Gene expression was detected and altered by qRT-PCR and cell transfection, respectively. The interaction between RP11-499E18.1 and PAK2, as well as that between PAK2 and SOX2, was determined using RNA pulldown, RNA immunoprecipitation (RIP), and co-immunoprecipitation (co-IP) assay, respectively. Localizations of RP11-499E18.1, PAK2, and SOX2 were respectively determined employing immunohistochemical (IHC), IF, and FISH. The regulatory effects of RP11-499E18.1, PAK2, and SOX2 on OC cell proliferation, migration, colony formation, epithelial-mesenchymal transition (EMT)-related factor expression, and SOX2 nuclear translocation were determined. Finally, the effects of RP11-499E18.1 and PAK2 expression on the tumor growth in nude mice were determined. Results: RP11-499E18.1, PAK2, and SOX2 were selected in our study. RP11-499E18.1 was downregulated, while PAK2 and SOX2 was upregulated in OC tissues and cells. RP11-499E18.1 coexists in the nucleus and cytoplasm of OC cells. There is an interaction between RP11-499E18.1 and PAK2, as well as PAK2 and SOX2 in OC cells. Alteration of RP11-499E18.1 and PAK2 expression both had no influence on PAK2 and SOX2 levels, but PAK2 upregulation notably augmented p-SOX2 level. RP11-499E18.1 overexpression suppressed OC cell proliferation, migration, and colony formation, as well as SOX2 nuclear translocation. Besides, it inhibited tumor growth in nude mice. However, these effects were notably reversed by PAK2 upregulation and eventually offset by SOX2 knockdown. Additionally, RP11-499E18.1 overexpression reduced PAK2-SOX2 interaction and SOX phosphorylation, and increased the binding of RP11-499E18.1 by PAK2. Conclusion: These lines of evidence demonstrated that RP11-499E18.1 might play its tumor suppressor roles in OC via regulation of the RP11-499E18.1-PAK2-SOX2 axis. This research indicated that RP11-499E18.1 might be used as a diagnostic biomarker for OC in the future.

Non-coding RNA Activated by DNA Damage: Review of Its Roles in the Carcinogenesis

Long intergenic non-coding RNA 00657 (LINC00657) or "non-coding RNA activated by DNA damage" (NORAD) is an extremely conserved and copious long non-coding RNA (lncRNA). This transcript has pivotal role in the preservation of genome integrity. Several researches have appraised the role of NORAD in the evolution of human cancers with most of them indicating an oncogenic role for this lncRNA. Several miRNAs such as miR-199a-3p, miR-608, miR-155-5p, miR-590-3p, miR-495-3p, miR-608, miR-202-5p, miR-125a-3p, miR-144-3p, miR-202-5p, and miR-30a-5p have been recognized as targets of NORAD in different cancer cell lines. In addition, NORAD has interactions with cancer-related pathways, particularly STAT, TGF-β, Akt/mTOR, and PI3K/AKT pathway. Over-expression of NORAD has been related with poor clinical outcome of patients with diverse types of neoplasms. Collectively, NORAD is a prospective marker and target for combating cancer.

Identification and Functional Validation of Differentially Expressed microRNAs in Ascites-Derived Ovarian Cancer Cells Compared with Primary Tumour Tissue

Purpose

Ovarian cancer, manifested by malignant ascites, is the most lethal gynaecological cancer. Suspended ascites-derived spheroids may contribute to ovarian cancer metastasis. MicroRNAs (miRNAs) are also associated with ovarian cancer metastasis. Here, we aimed to investigate the differentially expressed miRNAs (DE-miRNAs) in ascites-derived spheroids compared with primary tumour tissues, which may regulate ovarian cancer metastasis.

Methods

The DE-miRNAs between ovarian cancer primary tumour tissues and ascites-derived spheroids were identified by GEO2R screening in samples from 3 high-grade serous ovarian cancer (HGSOC) patients of dataset GSE65819. We used MiRTarBase, TargetScanHuman7.2 and STRING to predict the target hub genes of DE-miRNAs and DAVID to perform functional analysis of hub genes. ALGGEN PROMO and TransmiR v2.0 were used to predict transcription factors (TFs) that potentially regulate DE-miRNAs expression. The observed differences in DE-miRNAs expression were validated with samples from 12 HGSOC patients and 2 ovarian cancer cell lines using PCR. The functions of DE-miRNAs on ovarian cancer progression were verified by invasion, adherent, and angiogenesis assays.

Results

Through bioinformatics screening and experimental validation, miR-199a-3p, miR-199b-3p, miR-199a-5p, miR-126-3p and miR-145-5p were identified as being significantly downregulated in ascites-derived spheroids compared with primary tumour tissues. In addition, TFAP2A was identified as a potentially common upstream TF regulating the expression of the above mentioned DE-miRNAs. The overexpression of miR-199a-3p, miR-199b-3p, miR-199a-5p lead to invasion inhibition, and the overexpression of miR-126-3p, miR-145-5p, miR-199a-5p and miR-199b-3p lead to adhesion inhibition of suspended ovarian cancer cells. High-expressed miR-126-3p, miR-199a-3p, miR-199a-5p and miR-199b-3p contributed to apoptosis of suspended ovarian cancer cells.

Conclusion

The downregulated expression of miR-199a-3p, miR-199b-3p, miR-199a-5p, miR-126-3p and miR-145-5p in ascites-derived spheroids plays a key role in promoting ovarian cancer progression, which may represent novel molecules for targeted therapy for ovarian cancer.

LncRNA NORAD promotes bone marrow stem cell differentiation and proliferation by targeting miR-26a-5p in steroid-induced osteonecrosis of the femoral head

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is a devastating orthopedic disease, which seriously affects the quality of life of patients. The study aims to investigate the effects of LncRNA NORAD on SONFH.

METHODS

Human bone marrow-derived mesenchymal stem cells (hBMSCs) were isolated from the proximal femur of patients during routine orthopedic surgery and then cultured with dexamethasone (Dex) and transfected with NORAD overexpression vector, siRNA-NORAD and miR-26a-5p mimics. The mRNA expression of NORAD, miR-26a-5p, OPG, RANK, and RANKL was detected by RT-qPCR. Cell proliferation and apoptosis was measured by CCK-8 assay and flow cytometry, respectively. The protein expression of RUNX2, OPG, RANK, and RANKL was detected by western blot. The dual-luciferase reporter gene assay was performed to confirm the binding between NORAD and miR-26a-5p.

RESULTS

NORAD expression was downregulated in SONFH tissues, while miR-26a-5p expression was upregulated. Overexpression of NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis in hBMSCs, while knockdown of NORAD led to the opposite results. Moreover, NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis by regulation of miR-26a-5p in hBMSCs.

CONCLUSIONS

NORAD expression was downregulated in SONFH tissues, while miR-26a-5p expression was upregulated. NORAD improved DEX-induced inhibition of proliferation and differentiation, and promotion of apoptosis by regulation of miR-26a-5p in hBMSCs.

LncRNAs in Ovarian Cancer Progression, Metastasis, and Main Pathways: ceRNA and Alternative Mechanisms

Ovarian cancer (OvCa) develops asymptomatically until it reaches the advanced stages with metastasis, chemoresistance, and poor prognosis. Our review focuses on the analysis of regulatory long non-coding RNAs (lncRNAs) competing with protein-coding mRNAs for binding to miRNAs according to the model of competitive endogenous RNA (ceRNA) in OvCa. Analysis of publications showed that most lncRNAs acting as ceRNAs participate in OvCa progression: migration, invasion, epithelial-mesenchymal transition (EMT), and metastasis. More than 30 lncRNAs turned out to be predictors of survival and/or response to therapy in patients with OvCa. For a number of oncogenic (CCAT1, HOTAIR, NEAT1, and TUG1 among others) and some suppressive lncRNAs, several lncRNA/miRNA/mRNA axes were identified, which revealed various functions for each of them. Our review also considers examples of alternative mechanisms of actions for lncRNAs besides being ceRNAs, including binding directly to mRNA or protein, and some of them (DANCR, GAS5, MALAT1, and UCA1 among others) act by both mechanisms depending on the target protein. A systematic analysis based on the data from literature and Panther or KEGG (Kyoto Encyclopedia of Genes and Genomes) databases showed that a significant part of lncRNAs affects the key pathways involved in OvCa metastasis, EMT, and chemoresistance.

Silencing of Long Non-Coding RNA (LncRNA) Non-Coding RNA Activated by DNA Damage (NORAD) Inhibits Proliferation, Invasion, Migration, and Promotes Apoptosis of Glioma Cells via Downregulating the Expression of AKR1B1

Background

We aimed to investigate the functions of long non-coding RNA (lncRNA) non-coding RNA activated by DNA damage (NORAD) in glioma and identify the potential mechanisms.

Material/Methods

The expression of NORAD and AKR1B1 in human glioma cell lines were examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Then, cell proliferation, invasion, and migration were tested by Cell Counting Kit-8 (CCK-8), colony formation assay, Transwell, and scratch wound healing assay after NORAD silencing. Meanwhile, western blotting was utilized to measure the expression of migration-related proteins. Apoptosis of glioma cells was detected using flow cytometry and apoptosis-related proteins expression was determined. Moreover, the correlation between NORAD and AKR1B1 was verified by RNA-binding protein immunoprecipitation (RIP assay). After co-transfection with AKR1B1 overexpressed plasmid and NORAD siRNA, cell proliferation, invasion, migration, and apoptosis were examined again. Furthermore, the expression of proteins in extracellular signal-regulated kinase (ERK) signaling was tested using western blotting.

Results

The results revealed that NORAD and AKR1B1 were highly expressed in glioma cells. NORAD silencing inhibited proliferation, invasion and migration but promoted apoptosis of glioma cells, accompanied by the expression changes of migration- and apoptosis-related proteins. However, after co-transfection with AKR1B1 pcDNA3.1 in NORAD silencing cells, the effects of NORAD silencing on proliferation, invasion, migration, and apoptosis were attenuated. Consistently, the expression of phosphorylated ERK (p-ERK) was decreased after NORAD silencing, which were reversed following AKR1B1 overexpression.

Conclusions

These findings demonstrated that NORAD silencing suppressed proliferation, invasion, and migration and boosted apoptosis of glioma cells via downregulating the AKR1B1 expression, which may provide a potential therapeutic target for glioma treatment.

The Challenges and Opportunities of LncRNAs in Ovarian Cancer Research and Clinical Use

Ovarian cancer is one of the most lethal gynecological malignancies worldwide because it tends to be detected late, when the disease has already spread, and prognosis is poor. In this review we aim to highlight the importance of long non-coding RNAs (lncRNAs) in diagnosis, prognosis and treatment choice, to make progress towards increasingly personalized medicine in this malignancy. We review the effects of lncRNAs associated with ovarian cancer in the context of cancer hallmarks. We also discuss the molecular mechanisms by which lncRNAs become involved in cellular physiology; the onset, development and progression of ovarian cancer; and lncRNAs' regulatory mechanisms at the transcriptional, post-transcriptional and post-translational stages of gene expression. Finally, we compile a series of online resources useful for the study of lncRNAs, especially in the context of ovarian cancer. Future work required in the field is also discussed along with some concluding remarks.