LncRNA PVT1 Acts as a Tumor Promoter in Thyroid Cancer and Promotes Tumor Progression by Mediating miR-423-5p-PAK3

LINC02454 promotes thyroid carcinoma progression via upregulating HMGA2 through CREB1

Thyroid carcinoma (THCA) is the most common malignancy in the endocrine system. Long intergenic non-coding RNA 2454 (LINC02454) exhibits an HMGA2-like expression pattern, but their relationship and roles in THCA are largely unknown. The present purpose was to delineate the roles of LINC02454 in THCA progression and its molecular mechanisms. We collected THCA tissues from patients and monitored patient survival. THCA cell colony formation, migration, and invasion were evaluated. Metastasis was evaluated by examining EMT markers through Western blotting. Gene interaction was determined with ChIP, RIP, RNA pull-down, and luciferase activity assays. A mouse model of a subcutaneous tumor was used to determine the activity of LINC02454 knockdown in vivo. We found that LINC02454 was highly expressed in THCA, and its upregulation was associated with poor survival. The knockdown of LINC02454 repressed colony formation, migration, and invasion. Moreover, loss of LINC02454 inhibited tumor growth and metastasis in mice. HMGA2 promoted LINC02454 transcription via binding to the LINC02454 promoter, and silencing of HMGA2 suppressed malignant behaviors through downregulation of LINC02454. HMGA2 was a novel functional target of LINC02454 in THCA cells, and knockdown of LINC02454-mediated anti-tumor effects was reversed by HMGA2 overexpression. Mechanically, LINC02454 promoted CREB1 phosphorylation and nuclear translocation, and CREB1 was subsequently bound to the HMGA2 promoter to facilitate its expression. LINC02454 cis-regulates HMGA2 transcription via facilitating CREB1 phosphorylation and nuclear translocation, and, in turn, HMGA2 promotes LINC02454 expression, thus accelerating thyroid carcinoma progression. Our results support therapeutic targets of LINC02454 and HMGA2 for THCA.

Pseudogenes in Cancer: State of the Art

Pseudogenes are duplicates of protein-coding genes that have accumulated multiple detrimental alterations, rendering them unable to produce the protein they encode. Initially disregarded as "junk DNA" due to their perceived lack of functionality, research on their biological roles has been hindered by this assumption. Nevertheless, recent focus has shifted towards these molecules due to their abnormal expression in cancer phenotypes. In this review, our objective is to provide a thorough overview of the current understanding of pseudogene formation, the mechanisms governing their expression, and the roles they may play in promoting tumorigenesis.

Role of Long Intergenic Noncoding RNAs in Cancers with an Overview of MicroRNA Binding

Long intergenic noncoding RNAs are transcripts originating from the regions without annotated coding genes. They are located mainly in the nucleus and regulate gene expression. Long intergenic noncoding RNAs can be also found in the cytoplasm acting as molecular sponges of certain microRNAs. This is crucial in various biological and signaling pathways. Expression levels of many long intergenic noncoding RNAs are disease related. In this article, we focus on the long intergenic noncoding RNAs and their relation to different types of cancer. Studies showed that abnormal expression of long intergenic noncoding RNA deregulates signaling pathways due to the disrupted free microRNA pool. Hampered signaling pathways leads to abnormal cell proliferation and restricts cell death, thus resulting in oncogenesis. This review highlights promising therapeutic targets and enables the identification of potential biomarkers specific for a certain type of cancer. Moreover, we provide an outline of long intergenic noncoding RNAs/microRNA axes, which might be applied in further detailed experiments broadening our knowledge about the cellular role of those RNA species.

lncRNA PVT1: a novel oncogene in multiple cancers

Long noncoding RNAs are involved in epigenetic gene modification, including binding to the chromatin rearrangement complex in pre-transcriptional regulation and to gene promoters in gene expression regulation, as well as acting as microRNA sponges to control messenger RNA levels in post-transcriptional regulation. An increasing number of studies have found that long noncoding RNA plasmacytoma variant translocation 1 (PVT1) plays an important role in cancer development. In this review of a large number of studies on PVT1, we found that PVT1 is closely related to tumor onset, proliferation, invasion, epithelial–mesenchymal transformation, and apoptosis, as well as poor prognosis and radiotherapy and chemotherapy resistance in some cancers. This review comprehensively describes PVT1 expression in various cancers and presents novel approaches to the diagnosis and treatment of cancer.

Knockdown of PVT1 Exerts Neuroprotective Effects against Ischemic Stroke Injury through Regulation of miR-214/Gpx1 Axis

Previous studies have reported that lncRNA PVT1 was closely related to ischemic stroke. Here, the role of PVT1 in ischemic stroke and the underlying mechanism were investigated. OGDR-stimulated PC12 cells were used to construct a cell model to mimic ischemic stroke. si-PVT1, miR-214 mimic, inhibitor, or the negative controls were transfected into PC12 cells prior to OGDR treatment. PVT1, miR-214, and Gpx1 expression was measured by qRT-PCR and western blotting assays. Cell proliferation and apoptosis were tested by CCK-8 assay and western blotting. The expression levels of inflammatory factors were determined by ELISA Kit. Results showed that PVT1 was increased significantly in OGDR PC12 cells. PVT1 knockdown significantly enhanced cell viability and attenuated cell apoptosis, ROS generation, and inflammation in OGDR PC12 cells. More importantly, PVT1 or Gpx1 was a target of miR-214. Mechanistically, PVT1 acted as a competing endogenous RNA of miR-214 to regulate the downstream gene Gpx1. In conclusion, PVT1 knockdown attenuated OGDR PC12 cell injury by modulating miR-214/Gpx1 axis. These findings offer a potential novel strategy for ischemic stroke therapy.

LIMK2 Is a Novel Prognostic Biomarker and Correlates With Tumor Immune Cell Infiltration in Lung Squamous Cell Carcinoma

Previous research found that LIM domain kinase 2 (LIMK2) expression correlated with a poor prognosis in many cancers. However, its role in lung squamous cell carcinoma (LUSC) has not yet been clarified. Our study aimed to clarify the role of LIMK2 in LUSC prognosis prediction and explore the relationship between LIMK2 and immune infiltration in LUSC. In this study, we first analyzed the expression level and prognostic value of LIMK2 across cancers. Subsequently, we explored the association of LIMK2 expression with immune infiltrating cells and immune checkpoints. our study found that LIMK2 was highly expressed and positively associated with the overall survival of LUSC. Moreover, our study further indicated that LIMK2 expression was significantly negatively correlated with immune cell infiltration and immune checkpoints in LUSC. Finally, we confirmed upstream regulatory noncoding RNAs (ncRNAs) of LIMK2, and the PVT1 and DHRS4-AS1/miR-423-5p/LIMK2 regulatory axes were successfully constructed in LUSC. Put together, LIMK2 is a novel prognostic biomarker and correlates with tumor immune cell infiltration in LUSC, and the expression of LIMK2 is regulated by the PVT1 and DHRS4-AS1/miR-423-5p axes.

Identification of Candidate lncRNA and Pseudogene Biomarkers Associated with Carbon-Nanotube-Induced Malignant Transformation of Lung Cells and Prediction of Potential Preventive Drugs

Mounting evidence has linked carbon nanotube (CNT) exposure with malignant transformation of lungs. Long non-coding RNAs (lncRNAs) and pseudogenes are important regulators to mediate the pathogenesis of diseases, representing potential biomarkers for surveillance of lung carcinogenesis in workers exposed to CNTs and possible targets to develop preventive strategies. The aim of this study was to screen crucial lncRNAs and pseudogenes and predict preventive drugs. GSE41178 (small airway epithelial cells exposed to single- or multi-walled CNTs or dispersant control) and GSE56104 (lung epithelial cells exposed to single-walled CNTs or dispersant control) datasets were downloaded from the Gene Expression Omnibus database. Weighted correlation network analysis was performed for these two datasets, and the turquoise module was preserved and associated with CNT-induced malignant phenotypes. In total, 24 lncRNAs and 112 pseudogenes in this module were identified as differentially expressed in CNT-exposed cells compared with controls. Four lncRNAs (MEG3, ARHGAP5-AS1, LINC00174 and PVT1) and five pseudogenes (MT1JP, MT1L, RPL23AP64, ZNF826P and TMEM198B) were predicted to function by competing endogenous RNA (MEG3/RPL23AP64-hsa-miR-942-5p-CPEB2/PHF21A/BAMBI; ZNF826P-hsa-miR-23a-3p-SYNGAP1, TMEM198B-hsa-miR-15b-5p-SYNGAP1/CLU; PVT1-hsa-miR-423-5p-PSME3) or co-expression (MEG3/MT1L/ZNF826P/MT1JP-ATM; ARHGAP5-AS1-TMED10, LINC00174-NEDD4L, ARHGAP5-AS1/PVT1-NIP7; MT1L/MT1JP-SYNGAP1; MT1L/MT1JP-CLU) mechanisms. The expression levels and prognosis of all genes in the above interaction pairs were validated using lung cancer patient samples. The receiver operating characteristic curve analysis showed the combination of four lncRNAs, five pseudogenes or lncRNAs + pseudogenes were all effective for predicting lung cancer (accuracy >0.8). The comparative toxicogenomics database suggested schizandrin A, folic acid, zinc or gamma-linolenic acid may be preventive drugs by reversing the expression levels of lncRNAs or pseudogenes. In conclusion, this study highlights lncRNAs and pseudogenes as candidate diagnostic biomarkers and drug targets for CNT-induced lung cancer.

LncRNA HOX transcript antisense RNA mitigates cardiac function injury in chronic heart failure via regulating microRNA-30a-5p to target KDM3A

Long noncoding RNA HOX transcript antisense RNA (HOTAIR) has been studied in multiple diseases, but the role of HOTAIR on chronic heart failure (CHF) through the regulation of microRNA (miR)‐30a‐5p and lysine‐specific demethylase 3A (KDM3A) remains unexplored. This research aims to probe the effects of HOTAIR on CHF progression via modulating miR‐30a‐5p to target KDM3A. CHF mouse model was established by intraperitoneal injection of doxorubicin. The CHF mice were then injected with high‐expressed HOTAIR, miR‐30a‐5p or KDM3A adenovirus vectors to determine the cardiac function, oxidative stress, inflammatory response, pathological change and cardiomyocyte apoptosis. HOTAIR, miR‐30a‐5p, KDM3A and Bcl‐2/adenovirus E1B 19kDa interacting protein 3 (BNIP3) expression in CHF mice was detected. The binding relations among HOTAIR, miR‐30a‐5p and KDM3A were validated. HOTAIR and KDM3A were depleted, while miR‐30a‐5p was augmented in CHF mice. The elevated HOTAIR or KDM3A or could improve cardiac function, mitigate oxidative stress and pathological change, reduce inflammatory factor levels and cardiomyocyte apoptosis, while the increased miR‐30a‐5p exerted opposite effects. The miR‐30a‐5p elevation could reverse the effects of enriched HOTAIR, while BNIP3 reduction abrogated the effects of KDM3A on CHF. HOTAIR sponged miR‐30a‐5p that targeted KDM3A. HOTAIR improves cardiac injury in CHF via modulating miR‐30a‐5p to target KDM3A. This study provides novel therapeutic strategies for CHF treatment.