LncRNA MEG8 promotes NSCLC progression by modulating the miR-15a-5p-miR-15b-5p/PSAT1 axis

LncRNAs in tumor metabolic reprogramming and tumor microenvironment remodeling

The tumor microenvironment (TME) is a complex and dynamic ecosystem composed of tumor cells, immune cells, supporting cells, and the extracellular matrix. Typically, the TME is characterized by an immunosuppressive state. To meet the demands of rapid proliferation, cancer cells undergo metabolic reprogramming, which enhances their biosynthesis and bioenergy supply. Immune cells require similar nutrients for activation and proliferation, leading to competition and immunosuppression within the TME. Additionally, tumor metabolites inhibit immune cell activation and function. Consequently, an immunosuppressed and immune-tolerant TME promotes cancer cell proliferation and metastasis. Long non-coding RNAs (lncRNAs), a category of non-coding RNA longer than 200 nucleotides, regulate tumor metabolic reprogramming by interacting with key enzymes, transporters, and related signaling pathways involved in tumor metabolism. Furthermore, lncRNAs can interact with both cellular and non-cellular components in the TME, thereby facilitating tumor growth, metastasis, drug resistance, and inducing immunosuppression. Recent studies have demonstrated that lncRNAs play a crucial role in reshaping the TME by regulating tumor metabolic reprogramming. In this discussion, we explore the potential mechanisms through which lncRNAs regulate tumor metabolic reprogramming to remodel the TME. Additionally, we examine the prospects of lncRNAs as targets for anti-tumor therapy and as biomarkers for tumor prognosis.

Circulating lung-cancer-related non-coding RNAs are associated with occupational exposure to hexavalent chromium - A cross-sectional study within the SafeChrom project

BACKGROUND

Hexavalent chromium (Cr(Ⅵ)) is classified as a group 1 human carcinogen and increases the risk of lung cancer. Non-coding RNAs (ncRNAs) have key regulatory roles in lung cancer, but less is known about their relation to Cr(Ⅵ) exposure.

OBJECTIVES

We aimed to 1) measure the expression of lung cancer-related circulating ncRNAs in exposed workers and controls; 2) assess associations between ncRNAs expression and Cr concentrations in red blood cells (RBC) and urine; and 3) evaluate correlations between the ncRNAs.

METHODS

The study included 111 Cr(VI) exposed workers and 72 controls recruited from the SafeChrom project. Cr concentrations were measured in RBC (biomarker of long-term exposure) and urine (biomarker of short-term exposure) samples. Long ncRNA (lncRNA) and microRNA (miRNA) were extracted from plasma followed by deoxyribonuclease treatment, complementary DNA synthesis, and quantitative real-time polymerase chain reaction using target-specific assays for three lncRNAs (H19, MALAT1, NORAD), and four miRNAs (miR-142-3p, miR-15b-5p, miR-3940-5p, miR-451a).

RESULTS

Expression levels of lncRNAs MALAT1 and NORAD, and all four miRNAs, were significantly lower in Cr(VI) exposed workers compared with controls, and correlated significantly with RBC-Cr concentrations (rS = -0.16 to -0.38). H19 was non-significantly increased in exposed workers but significantly correlated with miR-142-3p (rS = -0.33) and miR-15b-5p (rS = -0.30), and NORAD was significantly positively correlated with all four miRNAs (rS = 0.17 to 0.46). In multivariate regression models adjusting for confounders, expressions of lncRNAs MALAT1 and NORAD and all miRNAs were still significantly lower in the exposed group compared with controls, and the expression decreased with increasing RBC-Cr concentrations.

CONCLUSIONS

Cr(VI) exposure was inversely and in a dose-response manner associated with the expression of circulating non-coding RNA, which suggests ncRNAs as potential biomarkers for Cr(VI)-induced toxicity. Correlations between miRNAs and lncRNAs suggest that they participate in the same lncRNA-miRNA-messenger RNA regulatory axes, which may play important roles in Cr(VI) carcinogenesis.

Testing the accuracy of a four serum microRNA panel for the detection of primary bladder cancer: a discovery and validation study

BACKGROUND

Bladder cancer (BC) is one of the ten most common cancers worldwide with late detection and early age of diagnosis. There is abundant evidence that early detection and timely intervention can lead to a better prognosis of BC. Substantial evidence has indicated that microRNAs (miRNAs) are specific to different tumour types and are remarkably stable, indicating that serum miRNAs may serve as potential cancer diagnostic markers. This study aimed to identify suitable serum miRNAs to create a panel that can be used to diagnose primary BC.

METHODS

In this study, 18 miRNAs that were differentially expressed in BC were obtained from the PubMed or Gene Expression Omnibus database. Then, 18 BC-related-miRNAs were verified in screening and validation sets created using 56 (28 primary BC vs. 28 NCs) and 168 (84 primary BC vs. 84 NCs) serum samples, respectively. Quantitative reverse transcription-PCR (qRT-PCR) was performed to verify the identity of the differential miRNAs. A multi-miRNA panel with superior diagnostic performance was constructed. TCGA and KEGG databases were used to conduct the survival analysis and bioinformatics analysis, respectively.

RESULTS

Six serum miRNAs (miR-221-5p, miR-181a-5p, miR-98-5p, miR-15a-5p, miR-222-3p, and miR-197-3p) were significantly aberrantly expressed in the BC patients, while four miRNAs from among them (miR-221-5p, miR-181a-5p, miR-15a-5p, miR-222-3p) were assembled into a panel that showed high diagnostic value (AUC = 0.875, 95% CI: 0.815 - 0.921; sensitivity: 82.14%; and specificity: 85.71%) based on the logistic regression analysis. The survival analysis showed that miR-181a-5p was closely associated with BC prognosis (Log-rank p-value < 0.05).

CONCLUSION

The combination of the four miRNAs (miR-221-5p, miR-181a-5p, miR-15a-5p and miR-222-3p) may be a novel non-invasive serological biomarker for BC screening.

Linc00662 sponges miR-15b-5p to promote hypopharyngeal squamous cell carcinoma progression by facilitating cancer stem cell-like phenotypes

Background: Long non-coding RNAs (lncRNAs) are associated with multiple head and neck tumors and play important roles in cancer. This study explored the molecular mechanism of Linc00662 in hypopharyngeal squamous cell carcinoma (HSCC). Methods: Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect gene expression in HSCC tissues. The viability and proliferation of tumor cells were measured using CCK-8 assays. HSCC cell apoptosis was measured using flow cytometry and western blotting. Cell stemness was examined using the sphere formation assay. A xenograft tumor model was established to investigate the role of Linc00662 in vivo. Results: The expression level of Linc00662 in HSCC tissues was significantly higher than that in adjacent normal tissues. The expression of Linc00662 had no significant relationship with the tumor stage. Patients with high Linc00662 expression were found to have shorter overall survival than those with low Linc00662 expression. Linc00662 over-expression promoted cell viability and inhibited apoptosis. Using online databases and a dual luciferase reporter, miR-15b-5p was confirmed as a potential downstream sponge of Linc00662. Moreover, Linc00662 was negatively associated with miR-15b-5p in HSCC cells. Depletion of miR-15b-5p can reverse the function of Linc00662 in vivo and in vitro. Furthermore, Linc00662 promotes tumor growth, which was abolished by miR-15b-5p mimics. Importantly, the stemness of cancer stem cells was mediated by the Linc00662/miR-15b-5p axis. Conclusion: Patients with HSCC with high Linc00662 showed poor prognosis and high Linc00662 induced stemness of tumor cells by targeting miR-15b-5p. Linc00662 may serve as a novel diagnostic and target marker for head and neck squamous cell carcinoma.

Targeting serine-glycine-one-carbon metabolism as a vulnerability in cancers

The serine-glycine-one-carbon (SGOC) metabolic pathway is critical for DNA methylation, histone methylation, and redox homeostasis, in addition to protein, lipid, and nucleotide biosynthesis. The SGOC pathway is a crucial metabolic network in tumorigenesis, wherein the outputs are required for cell survival and proliferation and are particularly likely to be co-opted by aggressive cancers. SGOC metabolism provides an integration point in cell metabolism and is of crucial clinical significance. The mechanism of how this network is regulated is the key to understanding tumor heterogeneity and overcoming the potential mechanism of tumor recurrence. Herein, we review the role of SGOC metabolism in cancer by focusing on key enzymes with tumor-promoting functions and important products with physiological significance in tumorigenesis. In addition, we introduce the ways in which cancer cells acquire and use one-carbon unit, and discuss the recently clarified role of SGOC metabolic enzymes in tumorigenesis and development, as well as their relationship with cancer immunotherapy and ferroptosis. The targeting of SGOC metabolism may be a potential therapeutic strategy to improve clinical outcomes in cancers.

Amino acid metabolism regulated by lncRNAs: the propellant behind cancer metabolic reprogramming

Metabolic reprogramming is one of the main characteristics of cancer cells and plays pivotal role in the proliferation and survival of cancer cells. Amino acid is one of the key nutrients for cancer cells and many studies have focused on the regulation of amino acid metabolism, including the genetic alteration, epigenetic modification, transcription, translation and post-translational modification of key enzymes in amino acid metabolism. Long non-coding RNAs (lncRNAs) are composed of a heterogeneous group of RNAs with transcripts of more than 200 nucleotides in length. LncRNAs can bind to biological molecules such as DNA, RNA and protein, regulating the transcription, translation and post-translational modification of target genes. Now, the functions of lncRNAs in cancer metabolism have aroused great research interest and significant progress has been made. This review focuses on how lncRNAs participate in the reprogramming of amino acid metabolism in cancer cells, especially glutamine, serine, arginine, aspartate, cysteine metabolism. This will help us to better understand the regulatory mechanism of cancer metabolic reprogramming and provide new ideas for the development of anti-cancer drugs. Video Abstract.

Comparative analysis of miRNA expression in dedifferentiated and well-differentiated components of dedifferentiated chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a rare malignant cartilage tumor arising out of a low-grade chondrosarcoma, whereby the well-differentiated and the dedifferentiated components coexist in the same localization. DDCS has a massively increased metastatic potential in comparison to low-grade chondrosarcoma. So far, the underlying mechanisms of DDCS development and the increased malignancy are widely unknown. Targeted DNA sequencing revealed no genetic differences between both tissue components. Besides genetic events, alterations in epigenetic control may play a role in DDCS development. In this preliminary study, we have analyzed the differential miRNA expression in paired samples of both components of four primary DDCS cases and a rare lung metastasis with both components using the nCounter MAX analysis system from NanoString technologies. We identified 21 upregulated and two downregulated miRNAs in the dedifferentiated components of the primary cases. Moreover, three miRNAs were also significantly deregulated in the dedifferentiated component of the lung metastasis, supporting their possible role in DDCS development. Additionally, validated targets of the 23 deregulated miRNAs are involved in signaling pathways, like PI3K/Akt, Wnt/β-catenin, and TGF-β, as well as in cellular processes, like cell cycle regulation, apoptosis, and dedifferentiation. Further investigations are necessary to confirm and understand the role of the identified miRNAs in DDCS development.

A novel circRNA, hsa_circ_0069382, regulates gastric cancer progression

Aberrant expression of circRNAs is closely associated with the progression of gastric cancer; however, the specific mechanisms involved remain unclear. Our aim was to identify new gastric cancer biomarkers and explore the molecular mechanisms of gastric cancer progression. Therefore, we analyzed miRNA and circRNA microarrays of paired early-stage gastric cancer samples. Our study identified a new circRNA called hsa_circ_0069382, that had not been reported before and was expressed at low levels in gastric cancer tissues. Our study also included bioinformatics analyses which determined that the high expression of hsa_circ_0069382 regulated the BTG anti-proliferation factor 2 (BTG2)/ focal adhesion kinase (FAK) axis in gastric cancer lines by sponging for miR-15a-5p. Therefore, proliferation, invasion, and migration of gastric cancer is impacted. miR-15a-5p overexpression partially restored the effects of hsa_circ_0069382. This study provides potential new therapeutic options and a future direction to explore for gastric cancer treatment, and biomarkers.

The role of serine metabolism in lung cancer: From oncogenesis to tumor treatment

Metabolic reprogramming is an important hallmark of malignant tumors. Serine is a non-essential amino acid involved in cell proliferation. Serine metabolism, especially the de novo serine synthesis pathway, forms a metabolic network with glycolysis, folate cycle, and one-carbon metabolism, which is essential for rapidly proliferating cells. Owing to the rapid development in metabolomics, abnormal serine metabolism may serve as a biomarker for the early diagnosis and pathological typing of tumors. Targeting serine metabolism also plays an essential role in precision and personalized cancer therapy. This article is a systematic review of de novo serine biosynthesis and the link between serine and folate metabolism in tumorigenesis, particularly in lung cancer. In addition, we discuss the potential of serine metabolism to improve tumor treatment.

Circular RNA circFARSA promotes the tumorigenesis of non-small cell lung cancer by elevating B7H3 via sponging miR-15a-5p

Non-small cell lung cancer (NSCLC) is currently one of the malignant tumors with the highest incidence and mortality rate in China. Circular RNA hsa_circ_0000896 (circFARSA) has been reported as being an oncogene and a potential biomarker for NSCL. However, the functional role and action mechanism of circFARSA in NSCLC progression have not been fully elucidated. The present study demonstrated that circFRASA was upregulated in NSCLC tissues and cell lines, and its expression was positively correlated with poor prognosis of patients with NSCLC. Further experiments revealed that circFARSA knockdown inhibited cell proliferation, migration, and invasion in vitro experiments, but overexpression of circFARSA exhibited opposite results. Mechanistically, circFARSA facilitated the malignant phenotype of NSCLC cells by enhancing B7H3 expression through sponging miR-15a-5p. In vivo experiments, knockdown of circFARSA restricted tumor growth and metastasis. In conclusion, circFARSA served as a sponge of miR-15a-5p to promote tumorigenesis and development of NSCLC by upregulation of B7H3 expression, which provided evidence of circFARSA maybe act as a novel therapeutic target for NSCLC.

LncRNA BANCR Promotes Endometrial Stromal Cell Proliferation and Invasion in Endometriosis via the miR-15a-5p/TRIM59 Axis

Long non-coding RNA (LncRNA) emerges as a regulator in various diseases, including endometriosis (EM). This study aims to uncover the role of long non-coding RNA BRAF-activated non-protein coding RNA (lncRNA BANCR)-mediated competing endogenous RNA mechanism in endometrial stromal cell (ESC) proliferation and invasion in EM by regulating miR-15a-5p/TRIM59. ESCs were isolated from eutopic and ectopic endometrial tissues, followed by the determination of Cytokeratin 19 and Vimentin expressions in cells. Then, expressions of lncRNA BANCR, microRNA (miR)-15a-5p, and tripartite motif-containing 59 (TRIM59) in tissues and cells were determined by real-time quantitative polymerase chain reaction or Western blot assay, and cell proliferation and invasion were evaluated by cell counting kit-8 and transwell assays. After that, the subcellular localization of lncRNA BANCR and binding of miR-15a-5p to lncRNA BANCR or TRIM59 were analyzed. LncRNA BANCR was upregulated in ectopic endometrial tissues and ectopic ESCs (Ect-ESCs). Silencing lncRNA BANCR suppressed Ect-ESC proliferation and invasion. LncRNA BANCR inhibited miR-15a-5p to promote TRIM59 expression. miR-15a-5p downregulation or TRIM59 overexpression both reversed the effects of silencing lncRNA BANCR on Ect-ESC proliferation and invasion. In summary, our findings suggested that lncRNA BANCR facilitated Ect-ESC proliferation and invasion by inhibiting miR-15a-5p and promoting TRIM59.

LncRNAs as epigenetic regulators of epithelial to mesenchymal transition in pancreatic cancer

Pancreatic cancer is the leading cause of cancer-related mortality because of tumor metastasis. Activation of the epithelial-to-mesenchymal transition (EMT) pathway has been confirmed to be an important driver of pancreatic cancer progression from initiation to metastasis. Long noncoding RNAs (lncRNAs) have been reported to exert essential physiological functions in pancreatic cancer progression by regulating the EMT program. In this review, we have summarized the role of EMT-related lncRNAs in human pancreatic cancer and the potential molecular mechanisms by which lncRNAs can be vital epigenetic regulators of epithelial to mesenchymal transition. Specifically, EMT-activating transcription factors (EMT-TFs) regulate EMT via TGF-β/Smad, Wnt/β-catenin, and JAK/STAT pathways. In addition, the interaction between lncRNAs and HIF-1α and m6A RNA methylation also have an impact on tumor metastasis and EMT in pancreatic cancer. This review will provide insights into lncRNAs as promising biomarkers for tumor metastasis and potential therapeutic strategies for pancreatic cancer.

MEG8：An Indispensable Long Non-coding RNA in Multiple Cancers

BACKGROUND

As a member of long non-coding RNAs (lncRNAs), maternally expressed gene 8 (MEG8) has been found involving in the progression of a variety of cancers and playing a regulatory role. Therefore, MEG8 may turn into a new therapeutic target for cancer in the future. The purpose of this review is to illustrate the molecular mechanism and physiological function of MEG8 in various cancers.

METHODS

We retrieved and analyzed related articles about MEG8, lncRNAs and cancers, and then summarize the pathophysiological mechanisms of MEG8 in cancer development.

RESULTS

LncRNA MEG8 participates in various cancers progression, thus influencing the proliferation, migration, and invasion of cancers. However, the expression of MEG8 is abnormally upregulated in non-small cell lung cancer (NSCLC), pancreatic cancer (PC), liver cancer (HCC), pituitary adenoma (PA) and hemangioma (HA), and inhibited in colorectal cancer (CRC), ovarian cancer (OC) and giant cell tumor (GCT), suggesting its clinical value in cancer therapy.

CONCLUSIONS

LncRNA MEG8 is expected to be a new therapeutic target or biomarker for a wide range of cancers in the future.

A Comprehensive Review on Function of miR-15b-5p in Malignant and Non-Malignant Disorders

miR-15b-5p is encoded by MIR15B gene. This gene is located on cytogenetic band 3q25.33. This miRNA participates in the pathogenesis of several cancers as well as non-malignant conditions, such as abdominal aortic aneurysm, Alzheimer’s and Parkinson’s diseases, cerebral ischemia reperfusion injury, coronary artery disease, dexamethasone induced steatosis, diabetic complications and doxorubicin-induced cardiotoxicity. In malignant conditions, both oncogenic and tumor suppressor impacts have been described for miR-15b-5p. Dysregulation of miR-15b-5p in clinical samples has been associated with poor outcome in different kinds of cancers. In this review, we discuss the role of miR-15b-5p in malignant and non-malignant conditions.

MicroRNA-15b-5p inhibits tumor necrosis factor alpha-induced proliferation, migration, and extracellular matrix production of airway smooth muscle cells via targeting yes-associated protein 1

The excessive proliferation and the deposition of extracellular matrix (ECM) of airway smooth muscle (ASM) cells facilitates airway remodeling in asthma. This study explores how microRNA-15b-5p (miR-15b-5p) functions in modulating the proliferation, migration, inflammatory response, and ECM deposition of ASM cells. MiR-15b-5p and yes-associated protein 1 (YAP1) mRNA expression levels in tumor necrosis factor alpha (TNF-α)-induced ASM cells were, respectively, examined by real-time quantitative polymerase-chain reaction. Besides, the proliferative ability and migrative potential of ASM cells were examined by cell counting kit-8 assay, 5-bromo-2 ‘-deoxyuridine assay, and transwell assays, respectively. Interleukin-6 and interleukin-8 levels in ASM cells were detected by enzyme-linked immunosorbent assay. YAP1, collagen I, and collagen III expressions in ASM cells were detected by Western blot. With dual-luciferase reporter gene assay, the relations between miR-15b-5p and YAP1 3ʹUTR in ASM cells was examined. MiR-15b-5p expression level was reduced in ASM cells treated with TNF-α. MiR-15b-5p repressed TNF-α-initiated growth and migration of ASM cells and also suppressed IL-6 and IL-8 secretion, and inhibited collagen I and collagen III expressions in ASM cells. Furthermore, it was validated that YAP1 was a downstream target of miR-15b-5p in ASM cells. Notably, YAP1 overexpression attenuated the inhibitory effects of miR-15b-5p up-regulation on the proliferation, migration, and inflammatory response, as well as ECM deposition of TNF-α-induced ASM cells. In conclusion, miR-15b-5p/YAP1 axis modulates the growth, migration, inflammatory response, and ECM deposition of ASM cells, thus participating in the pathogenesis of asthma.

Long non‑coding RNA LINC01748 exerts carcinogenic effects in non‑small cell lung cancer cell lines by regulating the microRNA‑520a‑5p/HMGA1 axis

The important functions of long non‑coding RNAs in the malignancy of non‑small cell lung cancer (NSCLC) has been increasingly highlighted. However, whether LINC01748 functions in a crucial regulatory role still requires further research. The aim of the present study was to investigate the biological roles of LINC01748 in NSCLC. Furthermore, different experiments were utilized to investigate the mechanism of action of LINC01748 in 2 NSCLC cell lines. Reverse transcription‑quantitative PCR was used to measure mRNA expression levels. Cell Counting Kit‑8 assay, flow cytometry analysis and Transwell and Matrigel assays were also used to analyze, cell viability, apoptosis, and migration and invasion, respectively. A tumor xenograft model was used for in vivo experiments. RNA immunoprecipitation experiments, luciferase reporter assays and rescue experiments were used to investigate the mechanisms involved. Data from The Cancer Genome Atlas dataset and patients recruited into the present study showed that LINC01748 was overexpressed in NSCLC. Patients with high LINC01748 mRNA expression level had shorter overall survival rate compared with that in patients with low LINC01748 mRNA expression level. Then, knockdown of LINC01748 mRNA expression level reduced cell proliferation, migration and invasion, but increased cell apoptosis in vitro. Knockdown of LINC01748 also reduced tumor growth in vivo. Mechanistically, LINC01748 could act as a competing endogenous (ce)RNA to sponge microRNA(miR)‑520a‑5p, to increase the expression level of the target gene, high mobility group AT‑hook 1 (HMGA1) in the NSCLC cell lines. Furthermore, rescue experiments illustrated that the functions exerted by LINC01748 knockdown were negated by miR‑520a‑5p inhibition or HMGA1 overexpression. In summary, LINC01748 acted as a ceRNA by sponging miR‑520a‑5p, leading to HMGA1 overexpression, thus increasing the aggressiveness of the NSCLC cells. Accordingly, targeting the LINC01748/miR‑520a‑5p/HMGA1 pathway may benefit NSCLC therapy.

Long Non-Coding RNA MEG8 Suppresses Hypoxia-Induced Excessive Proliferation, Migration and Inflammation of Vascular Smooth Muscle Cells by Regulation of the miR-195-5p/RECK Axis

It has been recognized that rebalancing the abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) helps relieve vascular injury. Presently, we aim to investigate whether long non-coding RNA (lncRNA) maternally expressed 8 (MEG8) plays a role in affecting the excessive proliferation and migration of VSMCs following hypoxia stimulation. A percutaneous transluminal angioplasty balloon dilatation catheter was adopted to establish vascular intimal injury, the levels of MEG8 and miR-195-5p in the carotid artery were tested by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Hypoxia was used to stimulate VSMCs, then the cell counting kit-8 (CCK-8) assay, Transnwell assay, and wound healing assay were conducted to evaluate the proliferation, and migration of VSMCs. The protein levels of RECK (reversion inducing cysteine rich protein with kazal motifs), MMP (matrix metalloproteinase) 3/9/13, COX2 (cytochrome c oxidase subunit II), macrophage inflammatory protein (MIP)-1beta, VCAM-1 (vascular cell adhesion molecule 1), ICAM-1 (intercellular adhesion molecule 1), and HIF-1α (hypoxia inducible factor 1 subunit alpha) were determined by western blot or cellular immunofluorescence. As the data showed, MEG8 was down-regulated in the carotid artery after balloon injury in rats and hypoxia-treated VSMCs, and miR-195-5p was overexpressed. Forced MEG8 overexpression or inhibiting miR-195-5p attenuated hypoxia-promoted cell proliferation and migration of VSMCs. In addition, miR-195-5p up-regulation reversed MEG8-mediated effects. Hypoxia hindered the RECK expression while boosted MMP3/9/13 levels, and the effect was markedly reversed with MEG8 up-regulation or miR-195-5p down-regulation. Mechanistically, MEG8 functioned as a competitive endogenous (ceRNA) by sponging miR-195-5p which targeted RECK. Moreover, the HIF-1α inhibitor PX478 prevented hypoxia-induced proliferation, and migration of VSMCs, upregulated MEG8, and restrained miR-195-5p expression. Overall, lncRNA MEG8 participated in hypoxia-induced excessive proliferation, inflammation and migration of VSMCs through the miR-195-5p/RECK axis.

Knockdown of lncRNA MEG8 inhibits cell proliferation and invasion, but promotes cell apoptosis in hemangioma, via miR‑203‑induced mediation of the Notch signaling pathway

As a member of the long non‑coding (lnc)RNA family, lncRNA maternally expressed 8, small nucleolar RNA host gene (MEG8), has been reported to serve an oncogenic role in several types of malignancies, including hepatocellular carcinoma, non‑small cell lung cancer and pancreatic cancer. The current study aimed to investigate the effect of the knockdown of MEG8 on human hemangioma endothelial cell (HemEC) proliferation, apoptosis and invasion, in addition to determining the underlying molecular mechanism. The knockdown of lncRNA MEG8 was achieved by transfecting lncRNA MEG8 small interfering (si)RNA into HemECs, while the combined knockdown of lncRNA MEG8 knockdown and microRNA (miR)‑203 was established by co‑transfecting lncRNA MEG8 siRNA and a miR‑203 inhibitor into HemECs. The cell proliferation, apoptosis and invasion and the expression levels of miR‑34a, miR‑200b, miR‑200b and Notch signaling pathway‑related factors were detected via CCK‑8 Kit, flow cytometry, Transwell, reverse transcription‑quantitative PCR and western blot assay, respectively. The knockdown of lncRNA MEG8 significantly inhibited proliferation (P<0.05) and invasion (P<0.05), but promoted apoptosis (P<0.01) in HemECs. Furthermore, lncRNA MEG8 knockdown upregulated miR‑203 (P<0.01) expression, but did not alter miR‑34a or miR‑200b expression (both P>0.05). Subsequent experiments revealed that miR‑203 silencing exerted no significant effect on the expression levels of lncRNA MEG8 (P>0.05) in HemECs. In addition, miR‑203 silencing increased cell proliferation (P<0.05) and invasion (P<0.01), but suppressed apoptosis (P<0.05). miR‑203 silencing also reversed the effect of lncRNA MEG8 knockdown on the proliferation (P<0.05), apoptosis (P<0.001) and invasion (P<0.01) of HemECs. Moreover, lncRNA MEG8 knockdown downregulated jagged canonical notch ligand 1 (JAG1; P<0.05) and Notch1 (P<0.05) expression levels, while miR‑203 silencing upregulated JAG1 (P<0.01) and Notch1 (P<0.01) expression levels and reversed the effects of lncRNA MEG8 knockdown on JAG1 (P<0.01) and Notch1 (P<0.01) expression in HemECs. In conclusion, the findings of the present study suggested that lncRNA MEG8 knockdown may inhibit cell proliferation and invasion, but promote cell apoptosis in hemangioma via miR‑203‑induced mediation of the Notch signaling pathway.

Human MicroRNAs Interacting With SARS-CoV-2 RNA Sequences: Computational Analysis and Experimental Target Validation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel RNA virus affecting humans, causing a form of acute pulmonary respiratory disorder named COVID-19, declared a pandemic by the World Health Organization. MicroRNAs (miRNA) play an emerging and important role in the interplay between viruses and host cells. Although the impact of host miRNAs on SARS-CoV-2 infection has been predicted, experimental data are still missing. This study started by a bioinformatics prediction of cellular miRNAs potentially targeting viral RNAs; then, a number of criteria also based on experimental evidence and virus biology were applied, giving rise to eight promising binding miRNAs. Their interaction with viral sequences was experimentally validated by transfecting luciferase-based reporter plasmids carrying viral target sequences or their inverted sequences into the lung A549 cell line. Transfection of the reporter plasmids resulted in a reduction of luciferase activity for five out of the eight potential binding sites, suggesting responsiveness to endogenously expressed miRNAs. Co-transfection of the reporter plasmids along with miRNA mimics led to a further and strong reduction of luciferase activity, validating the interaction between miR-219a-2-3p, miR-30c-5p, miR-378d, miR-29a-3p, miR-15b-5p, and viral sequences. miR-15b was also able to repress plasmid-driven Spike expression. Intriguingly, the viral target sequences are fully conserved in more recent variants such as United Kingdom variant B.1.1.7 and South Africa 501Y.V2. Overall, this study provides a first experimental evidence of the interaction between specific cellular miRNAs and SARS-CoV-2 sequences, thus contributing to understanding the molecular mechanisms underlying virus infection and pathogenesis to envisage innovative therapeutic interventions and diagnostic tools.