KCNQ1OT1/miR-217/ZEB1 feedback loop facilitates cell migration and epithelial-mesenchymal transition in colorectal cancer

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

Dysregulation of noncoding RNA in chordoma; implications in identifying potential targets for novel therapeutic approaches

Chordoma is a rare form of bone cancer develops in the spinal cord and skull. Instead of conventional (radio/chemotherapies) and targeted therapies, the disease is associated with high rate of recurrence and poor patient survival. Thus, for better disease management, the molecular pathogenesis of chordoma should be studied in detail to identify dysregulated biomolecules that can be targeted by novel therapeutics. Recent research showed frequent dysregulation of long noncoding RNA (lncRNA), microRNA (miRNA), and circular RNA (circRNA) in association with aggressive tumor phenotypes like cell proliferation, migration, invasion, and metastasis in a variety of cancers, including chordoma. Apart from diagnostic and prognostic importance, noncoding RNAs may serve as promising targets for novel therapeutics in cancer. In this review, we summarized a list of miRNAs, lncRNAs, and circRNA found to be dysregulated in chordoma from available data published in relevant databases (PubMed), as such an approach seems to be rare to date. The dysregulated noncoding RNAs were also associated with adverse tumor phenotypes to assess the impact on disease pathogenesis and, associated downstream molecular pathways were focused. Synthetic compounds and natural products that were reported to target the noncoding RNAs in other malignancies were also listed from published literature and proposed as potential therapeutic agents in chordoma. This review will provide information for further research on chordoma focusing on detailed characterization of dysregulated lncRNAs, miRNAs, and circRNA to understand the disease pathogenesis and, exploration of suitable natural and synthetic products targeting dysregulated non-coding RNAs to develop effective therapeutic measures.

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

MicroRNAs and colorectal cancer: clinical potential and regulatory networks

Colorectal cancer (CRC) is a serious global health concern, with a high incidence and mortality rate. Although there have been advancements in the early detection and treatment of CRC, therapy resistance is common. MicroRNAs (miRNAs), a type of small non-coding RNA that regulates gene expression, are key players in the initiation and progression of CRC. Recently, there has been growing attention to the complex interplay of miRNAs in cancer development. miRNAs are powerful RNA molecules that regulate gene expression and have been implicated in various physiological and pathological processes, including carcinogenesis. By identifying current challenges and limitations of treatment strategies and suggesting future research directions, this review aims to contribute to ongoing efforts to enhance CRC diagnosis and treatment. It also provides a comprehensive overview of the role miRNAs play in CRC carcinogenesis and explores the potential of miRNA-based therapies as a treatment option. Importantly, this review highlights the exciting potential of targeted modulation of miRNA function as a therapeutic approach for CRC.

Generation of Human Endometrial Assembloids with a Luminal Epithelium using Air-Liquid Interface Culture Methods

The endometrial lining of the uterus is essential for women's reproductive health and consists of several different types of epithelial and stromal cells. Although models such as gland-like structures (GLSs) and endometrial assembloids (EnAos) are successfully established, they lack an intact luminal epithelium, which makes it difficult to recapitulate endometrial receptivity. Here, a novel EnAo model (ALI-EnAo) is developed by combining endometrial epithelial cells (EnECs) and stromal cells (EnSCs) and using an improved matrix and air-liquid interface (ALI) culture method. ALI-EnAos exhibit intact EnSCs and glandular and luminal epithelia, which recapitulates human endometrium anatomy, cell composition, hormone-induced menstrual cycle changes, gene expression profiles, and dynamic ciliogenesis. The model suggests that EnSCs, together with the extracellular matrix and ALI culture conditions, contribute to EnAo phenotypes and characteristics reflective of the endometrial menstrual cycle. This enables to transcriptionally define endometrial cell subpopulations. It anticipates that ALI-EnAos will facilitate studies on embryo implantation, and endometrial growth, differentiation, and disease.

Associations between KCNQ1OT1 genetic variation rs10766212 and susceptibility to colorectal cancer and clinical stage in a Chinese Han population

KCNQ1OT1 has been linked to the development and progression of colorectal cancer (CRC). As a result, functional polymorphisms in the KCNQ1OT1 gene may have a role in CRC formation and progression. The goal of this study was to see if the rs10766212 polymorphism on the KCNQ1OT1 gene was linked to CRC susceptibility and clinical stage in a Chinese Han population. The case-control research comprised a total of 576 CRC patients and 606 healthy controls. The genotype of the rs10766212 polymorphic locus was determined using the Sanger sequencing technique. We found that the KCNQ1OT1 rs10766212 polymorphism was not related to CRC susceptibility; however, it was connected with the clinical stage of CRC. Patients with CRC who had the rs10766212 T allele had a lower risk of stage III/IV tumors than those who had the rs10766212 C allele. Furthermore, CRC tissues with the rs10766212 CC genotype showed a significant negative connection between KCNQ1OT1 and hsa-miR-622 expression. The luciferase assay showed that the rs10766212 C allele might contribute to the adsorption of KCNQ1OT1 on hsa-miR-622. In conclusion, the rs10766212 polymorphism altering hsa-miR-622 binding is linked to the clinical stage of CRC and may serve as a biomarker for predicting CRC progression in the Chinese Han population. However, better-designed studies are still needed to confirm the current findings.

Up-regulated Circular RNAs in Colorectal Cancer: New Entities for Therapy and Tools for Identification of Therapeutic Targets

Patients with disseminated colorectal cancer have a dismal prognosis with a 5-year survival rate of only 13%. In order to identify new treatment modalities and new targets, we searched the literature for up-regulated circular RNAs in colorectal cancer which induce tumor growth in corresponding preclinical in vivo models. We identified nine circular RNAs that mediate resistance against chemotherapeutic agents, seven that up-regulate transmembrane receptors, five that induce secreted factors, nine that activate signaling components, five which up-regulate enzymes, six which activate actin-related proteins, six which induce transcription factors and two which up-regulate the MUSASHI family of RNA binding proteins. All of the circular RNAs discussed in this paper induce the corresponding targets by sponging microRNAs (miRs) and can be inhibited by RNAi or shRNA in vitro and in xenograft models. We have focused on circular RNAs with demonstrated activity in preclinical in vivo models because the latter is an important milestone in drug development. All circular RNAs with in vitro activity only data are not referenced in this review. The translational impact of inhibition of these circular RNAs and of the identified targets for treatment of colorectal cancer (CRC) are discussed.

The ceRNA network regulates epithelial-mesenchymal transition in colorectal cancer

Epithelial-mesenchymal transition (EMT) is a biological process that transforms epithelial cells into a mesenchymal phenotype, conferring cell migration and invasion capabilities. EMT is involved in the progression and metastasis of colorectal cancer (CRC). Recently, emerging evidence has shown dysregulation of non-coding RNA (ncRNA) was linked to EMT. ncRNAs, including long non-coding RNA (lncRNA), regulate the transcription of downstream target genes (mRNA) through interaction with microRNAs (miRNAs); these are termed competitive endogenous RNA (ceRNA) networks. CeRNA dysregulation-induced EMT, which is linked to the progression and prognosis of CRC, has attracted wide attention. However, understanding the role of the regulation of the ceRNA network in the EMT of CRC remains limited. We discuss the molecular functions of lncRNA, the ceRNA networks related to miRNAs and mRNAs in EMT, as well as EMT transcription factors, such as the zinc finger E-box binding homeobox 1/2 (ZEB1/2), SNAIL, SLUG, and TWIST1/2. In addition, miRNAs and lncRNAs that directly target genes, thereby initiating different signaling pathways to promote EMT in CRC, were summarized. Clarifying the role of these molecules in EMT is critical for understanding molecular mechanisms and exploring the potential therapeutic targets of CRC.

Integrated analysis of lncRNA-associated ceRNA network in p16-positive and p16-negative head and neck squamous cell carcinoma

Determination of human papillomavirus (HPV) status has become clinically relevant for head and neck squamous cell carcinoma (HNSCC) patients. p16 immunohistochemistry is one of the recommended methods for classifying HPV status. However, long noncoding RNAs (lncRNAs) and related competing endogenous RNA (ceRNA) networks linked to different p16-status HNSCC are still absent. In the present study, The Cancer Genome Atlas database provided RNA profiles as well as clinical information from 26 p16-positive HNSCC samples, 71 p16-negative HNSCC samples, and 44 adjacent normal control samples. Differentially expressed RNAs (DERNAs) between HNSCC samples and normal samples were identified by limma package in R. Functional enrichment analysis of differentially expressed mRNAs was performed using Clusterprofiler package in R. Survival analysis of DERNAs was carried out by survival package in R. The ceRNA network was constructed using GDCRNATools package in R. A total of 102 lncRNAs, 196 microRNAs (miRNAs), and 2282 mRNAs were identified as p16-positive-specific DERNAs. There were 90 lncRNAs, 153 miRNAs, and 2038 mRNAs were identified as p16-negative-specific DERNAs. Functional enrichment analysis revealed that the differentially expressed mRNAs in the p16-positive and the p16-negative group were mainly enriched in the "DNA replication" and "extracellular matrix -receptor interaction" pathway, respectively. Among the top 25 DERNAs, there were 1 key lncRNA, 1 key miRNA, and 1 key messenger RNA in the p16-positive group and 2 key lncRNAs, 1 key miRNA, and 2 key mRNAs in the p16-negative group were significantly related to the overall survival. Then the ceRNA network in the p16-positive and p16-negative group was constructed. There were 5 lncRNAs, 16 miRNAs, and 66 mRNAs included in the p16-positive group ceRNA network and 1 lncRNA, 4 miRNAs, and 28 mRNAs included in the p16-negative group ceRNA network. Among the RNAs in the ceRNA network, 5 mRNAs were significantly related to the overall survival. Taken together, we revealed the differential RNA expression profiling and the differential ceRNA network in the p16-positive and p16-negative group of HNSCC. Our findings provided a novel insight into this HPV-related cancer and potential biomarkers and therapeutic targets for HNSCC based on p16 status.

Downregulation of Kcnq1ot1 attenuates β-cell proliferation and insulin secretion via the miR-15b-5p/Ccnd1 and Ccnd2 axis

AIM

To examine the effect of lncRNA Kcnq1ot1 on pancreatic β cells in the development of diabetes.

METHODS

The expression levels of Kcnq1ot1 were detected in the islets of diabetes mouse models and the serum of patients with type 2 diabetes by qRT-PCR. CCK8, Ki67 staining, immunohistochemical analyses, glucose-stimulated insulin secretion and intraperitoneal glucose tolerance test were performed to detect the effect of Kcnq1ot1 on β-cell proliferation and insulin secretion in vitro and in vivo. The relationship between Kcnq1ot1 and miR-15b-5p was predicted by bioinformatics prediction, which was confirmed by luciferase reporter assay.

RESULTS

Kcnq1ot1 was more abundant in the pancreas. The expression of Kcnq1ot1 was decreased in the islets of db/db mice and diet-induced obese mice and in the serum of patients with type 2 diabetes. Silencing Kcnq1ot1 inhibited the β-cell proliferation concomitant with a reduction in the levels of Ccnd1 and Ccnd2. Insulin synthesis and secretion were impaired, along with the decreased expression of Ins1, Ins2, and insulin-related transcription factors. Moreover, Kcnq1ot1 knockdown in vivo reduced glucose tolerance and decreased insulin secretion, consistent with the reduction in the relative islet area and Ki67-positive β-cells detected by immunochemistry and immunofluorescence staining, respectively. Mechanistically, Kcnq1ot1 directly targeted miR-15b-5p which regulated β-cell proliferation and insulin secretion through Ccnd1 and Ccnd2. Notably, the suppression of miR-15b-5p attenuated the inhibition of Min6 proliferation and insulin production induced by Kcnq1ot1 knockdown.

CONCLUSION

Kcnq1ot1 regulated β-cell proliferation and insulin secretion via the miR-15b-5p/Ccnd1 and Ccnd2 axis, which is worthy of further investigation considering its potential in diabetes treatment.

Long Non-Coding RNAs as Potential Regulators of EMT-Related Transcription Factors in Colorectal Cancer—A Systematic Review and Bioinformatics Analysis

Simple Summary

Emerging evidence highlights long non-coding RNAs as important regulators of epithelial–mesenchymal transition. Numerous studies have attempted to define their possible diagnostic, prognostic and therapeutic values in various human cancers. The aim of this review is to summarize long non-coding RNAs involved in the regulation of epithelial–mesenchymal transition in colorectal carcinoma. Additional candidate long non-coding RNAs are identified through a bioinformatics analysis.

Abstract

Epithelial–mesenchymal transition (EMT) plays a pivotal role in carcinogenesis, influencing cancer progression, metastases, stemness, immune evasion, metabolic reprogramming and therapeutic resistance. EMT in most carcinomas, including colorectal carcinoma (CRC), is only partial, and can be evidenced by identification of the underlying molecular drivers and their regulatory molecules. During EMT, cellular reprogramming is orchestrated by core EMT transcription factors (EMT-TFs), namely ZEB1/2, TWIST1/2, SNAI1 (SNAIL) and SNAI2 (SLUG). While microRNAs have been clearly defined as regulators of EMT, the role of long non-coding RNAs (lncRNAs) in EMT is poorly defined and controversial. Determining the role of lncRNAs in EMT remains a challenge, because they are involved in a number of cellular pathways and are operating through various mechanisms. Adding to the complexity, some lncRNAs have controversial functions across different tumor types, acting as EMT promotors in some tumors and as EMT suppressors in others. The aim of this review is to summarize the role of lncRNAs involved in the regulation of EMT-TFs in human CRC. Additional candidate lncRNAs were identified through a bioinformatics analysis.

LncRNA KCNQ1OT1-mediated cervical cancer progression by sponging miR-1270 as a ceRNA of LOXL2 through PI3k/Akt pathway

BACKGROUND

Dysregulated noncoding RNAs participated in progressions of cervical cancer.

PURPOSE

To verify impacts of KCNQ1OT1 on modulating progressions of cervical cancer cells.

METHOD

Expressions of KCNQ1OT1, miR-1270, and LOXL2 were analyzed through RT-qPCR and protein expressions of LOXL2, p-AKT, and AKT were validated using western blot. Bindings of miR-1270 with KCNQ1OT1 or LOXL2 were verified using luciferase reporter assay. CCK-8 and flow cytometry evaluated cell viability and apoptosis, respectively. The PI3K/AKT signaling pathway suppressor, LY294002, was applied to treat the cells and the changes of KCNQ1OT1 expression and LOXL2, p-AKT, and AKT protein expressions were examined.

RESULTS

KCNQ1OT1 expression was the highest in HeLa cells but lowest in SiHa cells whose upregulation improved the viability but inhibited the apoptosis in SiHa cells while knockdown of KCNQ1OT1 caused opposite results in HeLa cells. MiR-1270 was sponged and negatively modulated by KCNQ1OT1. MiR-1270 mimics caused low viability and high apoptosis of SiHa cells but miR-1270 inhibitor reverse its roles in HeLa cells. LOXL2, the target of miR-1270, positively interplayed with KCNQ1OT1 but had negative interaction with miR-1270. LOXL2 overexpression promoted viability and decreased apoptosis of SiHa cells but knockdown of LOXL2 restored its effects in HeLa cells. Moreover, LOXL2 and phosphorylated AKT (p-AKT) protein expressions were downregulated by suppressed KCNQ1OT1 and LOXL2 and miR-1270 mimics but promoted by overexpressed KCNQ1OT1 and LOXL2 and miR-1270 inhibitor. Additionally, LY294002 treatment caused low KCNQ1OT1 RNA expression and decreased LOXL2 and p-AKT protein expressions.

CONCLUSION

KCNQ1OT1/miR-1270/LOXL2 axis modulated viability and apoptosis of cervical cancer cells.

Long non-coding RNAs as the critical regulators of epithelial mesenchymal transition in colorectal tumor cells: an overview

Colorectal cancer (CRC) is the second most common cause of cancer mortality and a major health challenge worldwide. Despite advances in therapeutic and diagnostic methods, there is still a poor prognosis in CRC patients. Tumor recurrence and metastasis are the main causes of high mortality rate in these patients, which are due to late diagnosis in advanced tumor stages. Epithelial-mesenchymal transition (EMT) is known to be the most important cause of CRC metastasis, during which tumor cells obtain metastasis ability by losing epithelial features and gaining mesenchymal features. Long non-coding RNAs (lncRNAs) are pivotal regulators of EMT process. Regarding the higher stability of lncRNAs compared with coding RNAs in body fluids, they can be used as non-invasive diagnostic markers for EMT process. In the present review, we summarized all of the lncRNAs involved in regulation of EMT process during CRC progression and metastasis. It was observed that lncRNAs mainly induced the EMT process in CRC cells by regulation of EMT-related transcription factors, Poly comb repressive complex (PRC), and also signaling pathways such as WNT, NOTCH, MAPK, and Hippo.

MicroRNA-217: a therapeutic and diagnostic tumor marker

INTRODUCTION

Cancer as one of the most common causes of death has always been one of the major health challenges globally. Since, the identification of tumors in the early tumor stages can significantly reduce mortality rates; it is required to introduce novel early detection tumor markers. MicroRNAs (miRNAs) have pivotal roles in regulation of cell proliferation, migration, apoptosis, and tumor progression. Moreover, due to the higher stability of miRNAs than mRNAs in body fluids, they can be considered as non-invasive diagnostic or prognostic markers in cancer patients.

AREAS COVERED

In the present review we have summarized the role of miR-217 during tumor progressions. The miR-217 functions were categorized based on its target molecular mechanisms and signaling pathways.

EXPERT OPINION

It was observed that miR-217 mainly exerts its function by regulation of the transcription factors during tumor progressions. The WNT, MAPK, and PI3K/AKT signaling pathways were also important molecular targets of miR-217 in different cancers. The present review clarifies the molecular biology of miR-217 and paves the way of introducing miR-217 as a non-invasive diagnostic marker and therapeutic target in cancer therapy.

ALKBH5-mediated m6A modification of lncRNA KCNQ1OT1 triggers the development of LSCC via upregulation of HOXA9

It has been shown that N6‐methyladenosine (m6A) modification is involved in the development of complex human diseases, especially in the development of cancer. Our research investigated the role and mechanism of the m6A modification of lncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) in Laryngeal squamous cell carcinoma (LSCC) progression. Microarray analysis was used to quantitatively detect the m6A apparent transcriptional modification level of lncRNA in LSCC tissue. Methylated RNA immunoprecipitation‐qPCR (MeRIP‐qPCR), in situ hybridization (ISH) and quantitative real‐time PCR (qRT‐PCR) were used to examine the m6A modification and expression of KCNQ1OT1. In addition, in vivo and in vitro experiments have tested the effects of KCNQ1OT1 knockdown on the proliferation, invasion and metastasis of LSCC. Mechanically, we found the N6‐methyladenosine (m6A) demethylase ALKBH5 mediates KCNQ1OT1 expression via an m6A‐YTHDF2‐dependent manner and KCNQ1OT1 could directly bind to HOXA9 to further regulate the proliferation, invasion and metastasis of LSCC cells. In general, our research indicates that ALKBH5‐mediated m6A modification of KCNQ1OT1 triggers the development of LSCC via upregulation of HOXA9.

Long noncoding RNA KCNQ1 opposite strand/antisense transcript 1 promotes osteosarcoma progression through miR-154-3p/KLF12

OBJECTIVE

Osteosarcoma (OS) is a common bone cancer that usually influences children. Metastasis and recurrence are the main reasons for the poor prognosis. In this study, we investigated the functions and mechanisms of KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in OS.

METHODS

Cell viability and proliferation were detected using the CCK-8 assay and the 5-Ethynyl-2'-deoxyuridine (EdU) assay. Wound-healing assays, transwell assay and flow cytometry were used to identify cell migration, invasion, and apoptosis, respectively. The relationship among KCNQ1OT1, miR-154-3p, and KLF12 was verified by luciferase reporter assay and restricting protein immunoprecipitation (RIP) assay. Xenograft models were established to confirm the function of KCNQ1OT1 in vivo.

RESULTS

The expression of KCNQ1OT1 was higher in OS than in non-tumor tissues and cells. Knockdown of KCNQ1OT1 could reduce OS cell proliferation, migration, and invasion and promoted cell death. Mechanistically, KCNQ1OT1 contributed to OS formation by acting as a competitive endogenous RNA (ceRNA) and influencing miR-154-3p expression. Furthermore, we confirmed that miR-154-3p affected KLF12 expression through binding the 3'UTR region. Finally, rescue experiments determined that KCNQ1OT1 exerted major roles in OS through the miR-154-3p/KLF12 axis.

CONCLUSION

In conclusion, our research explains the mechanism of KCNQ1OT1 in OS progression, which could serve as a new therapeutic target.

c-Myc affects hedgehog pathway via KCNQ1OT1/RAC1: A new mechanism for regulating HSC proliferation and epithelial-mesenchymal transition

BACKGROUND

This study aimed to probe into the potential mechanism of KCNQ1OT1 in liver fibrosis.

METHODS

The pathological changes in liver tissues were observed by Masson and hematoxylin-eosin (HE) staining. The proliferation or cell cycle of hepatic stellate cells (HSCs) was analyzed by MTT or flow cytometry. The expressions of epithelial markers E-cadherin, interstitial markers Snail and Vimentin, and hedgehog signaling pathway-related molecules Hhip, Shh, and Gli2 were detected by Western blot. The interaction or binding of c-Myc with the KCNQ1OT1 promoter was analyzed by dual-luciferase reporter gene or Chromatin immunoprecipitation (ChIP)-qPCR, and the interaction between KCNQ1OT1 and RAC1 was assessed by RNA immunoprecipitation and RNA pull-down. Moreover, the stability of RAC1 protein was detected by cycloheximide-chase and ubiquitination.

RESULTS

c-Myc and KCNQ1OT1 were up-regulated in liver fibrosis tissues and cells. After the interference with c-Myc in primary-1-Day HSCs, the down-regulated KCNQ1OT1 restrained HSC proliferation and EMT by down-regulating RAC1 expression and restraining the hedgehog pathway.

CONCLUSION

Our results indicated that the interference with c-Myc down-regulated RAC1 expression and restrained the hedgehog pathway by down-regulating KCNQ1OT1, thus restraining HSC proliferation and EMT in liver fibrosis.

KCNQ1OT1: An Oncogenic Long Noncoding RNA

Long noncoding RNAs (lncRNAs) are transcripts greater than 200 nucleotides that do not code for proteins but regulate gene expression. Recent studies indicate that lncRNAs are involved in the modulation of biological functions in human disease. KCNQ1 Opposite Strand/Antisense Transcript 1 (KCNQ1OT1) encodes a lncRNA from the opposite strand of KCNQ1 in the CDKN1C/KCNQ1OT1 cluster that is reported to play a vital role in the development and progression of cancer. KCNQ1OT1 regulates cancer cell proliferation, cell cycle, migration and invasion, metastasis, glucose metabolism, and immune evasion. The aberrant expression of KCNQ1OT1 in cancer patients is associated with poor prognosis and decreased survival. This review summarizes recent literature related to the biological functions and molecular mechanisms of KCNQ1OT1 in various human cancers, including colorectal, bladder, breast, oral, melanoma, osteosarcoma, lung, glioma, ovarian, liver, acute myeloid leukemia, prostate, and gastric. We also discuss the role of KCNQ1OT1 as a promising diagnostic biomarker and a novel therapeutic target in human cancers.

A Positive Feedback Loop of lncRNA MIR31HG-miR-361-3p -YY1 Accelerates Colorectal Cancer Progression Through Modulating Proliferation, Angiogenesis, and Glycolysis

Background

Colorectal cancer (CRC) is a common malignant tumor with high metastatic and recurrent rates. This study probes the effect and mechanism of long non-coding RNA MIR31HG on the progression of CRC cells.

Materials and Methods

Quantitative real-time PCR (qRT-PCR) was used to analyze the expression of MIR31HG and miR-361-3p in CRC tissues and normal tissues. Gain- or loss-of-function assays were conducted to examine the roles of MIR31HG, miR-361-3p and YY1 transcription factor (YY1) in the CRC progression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and colony formation experiment were conducted to test CRC cell proliferation. CRC cell invasion was determined by Transwell assay. The glucose detection kit and lactic acid detection kit were utilized to monitor the levels of glucose and lactate in CRC cells. The glycolysis level in CRC cells was examined by the glycolytic stress experiment. Western blot was performed to compare the expression of glycolysis-related proteins (PKM2, GLUT1 and HK2) and angiogenesis-related proteins (including VEGFA, ANGPT1, HIF1A and TIMP1) in HUVECs. The binding relationships between MIR31HG and miR-361-3p, miR-361-3p and YY1 were evaluated by the dual-luciferase reporter assay and RNA immunoprecipitation (RIP).

Results

MIR31HG was up-regulated in CRC tissues and was associated with poorer prognosis of CRC patients. The in-vitro and in-vivo experiments confirmed that overexpressing MIR31HG heightened the proliferation, growth, invasion, glycolysis and lung metastasis of CRC cells as well as the angiogenesis of HUVECs. In addition, MIR3HG overexpression promoted YY1 mRNA and protein level, and forced overexpression of YY1 enhanced MIR31HG level. Overexpressing YY1 reversed the tumor-suppressive effect mediated by MIR31HG knockdown. miR-361-3p, which was inhibited by MIR31HG overexpression, repressed the malignant behaviors of CRC cells. miR-361-3p-mediated anti-tumor effects were mostly reversed by upregulating MIR31HG. Further mechanism studies illustrated that miR-361-3p targeted and negatively regulated the expression of YY1.

Conclusion

This study reveals that MIR31HG functions as an oncogenic gene in CRC via forming a positive feedback loop of MIR31HG-miR-361-3p-YY1.

Modelling the impact of decidual senescence on embryo implantation in human endometrial assembloids

Decidual remodelling of midluteal endometrium leads to a short implantation window after which the uterine mucosa either breaks down or is transformed into a robust matrix that accommodates the placenta throughout pregnancy. To gain insights into the underlying mechanisms, we established and characterized endometrial assembloids, consisting of gland-like organoids and primary stromal cells. Single-cell transcriptomics revealed that decidualized assembloids closely resemble midluteal endometrium, harbouring differentiated and senescent subpopulations in both glands and stroma. We show that acute senescence in glandular epithelium drives secretion of multiple canonical implantation factors, whereas in the stroma it calibrates the emergence of anti-inflammatory decidual cells and pro-inflammatory senescent decidual cells. Pharmacological inhibition of stress responses in pre-decidual cells accelerated decidualization by eliminating the emergence of senescent decidual cells. In co-culture experiments, accelerated decidualization resulted in entrapment of collapsed human blastocysts in a robust, static decidual matrix. By contrast, the presence of senescent decidual cells created a dynamic implantation environment, enabling embryo expansion and attachment, although their persistence led to gradual disintegration of assembloids. Our findings suggest that decidual senescence controls endometrial fate decisions at implantation and highlight how endometrial assembloids may accelerate the discovery of new treatments to prevent reproductive failure.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

Comprehensive analysis of lncRNA-miRNA-mRNA regulatory networks for microbiota-mediated colorectal cancer associated with immune cell infiltration

Recent findings have identified microbiota as crucial participants in many disease conditions, including cancers. Competing endogenous RNA (ceRNA) is regarded as a candidate mechanism involving relevant biological processes. We therefore constructed a ceRNA network using the TCGA and GEO database, to determine the potential mechanisms of microbiota-mediated colorectal carcinogenesis and progression. We found a total of 75 lncRNAs, 8 miRNAs, and 9 mRNAs in the probiotics-mediated ceRNA network and a total of 49 lncRNAs, 4 miRNAs, and 3 mRNA in the pathobiont-mediated ceRNA network, which could induce the microbiota-mediated carcinogenesis and progression. The GO and KEGG analysis indicated that the ceRNA network is mainly enriched in the metabolic process, and two unique pathways (the p53 signaling pathway and microRNA in cancer), respectively. A four-gene signature (FRMD6-AS2, DIRC3, LIFR-AS1, and MRPL23-AS1) was suggested as an independent prognostic factor. Four lncRNAs (LINC00355, KCNQ1OT1, LINC00491, and HOTAIR) were associated with poor survival. Three small molecule candidate anticancer drugs (Pentoxyverine, Rimexolone, and Doxylamine) were identified. A four-gene signature (FAM129A, BCL2, PMAIP1, and RPS6) is significantly correlated with immune infiltration level. This study provides a promising biomarker reservoir to explore the mechanism by which microbiota regulate the ceRNA network involving the immune response, and further participate in colorectal carcinogenesis and progression.

KCNQ1OT1 lncRNA affects the proliferation, apoptosis, and chemoresistance of small cell lung cancer cells via the JAK2/STAT3 axis

Background

Small cell lung cancer (SCLC) is a devastating and aggressive neuroendocrine carcinoma characterized by high cellular proliferation and early metastatic spread. Numerous studies have demonstrated that long noncoding RNAs (lncRNAs) can regulate tumor generation and development, including in SCLC. The current study aimed to assess the effect of the lncRNA, KCNQ1OT1, on the proliferation, apoptosis, and chemoresistance of SCLC and the potential underlying molecular mechanism.

Methods

Matched chemo-resistant and sensitive cells were applied to RNA isolation and followed by expression profiling by microarray analysis and subsequent quantitative polymerase chain reaction (qPCR) validation. Cell viability and apoptosis were determined by Cell Counting Kit-8 and flow cytometry to examine the chemoresistance and apoptosis of KCNQ1OT1 knockdown with lentivirus-mediated RNA interference. Furthermore, cell proliferation was studied by colony formation, and invasion and migration were tested by Transwell cell invasion and wound-healing assays, respectively. A tumor xenograft model was established to determine the role of KCNQ1OT1 in tumor growth and chemoresistance in response to KCNQ1OT1 knockdown in vivo. Western blot analysis, qPCR, and immunohistochemistry were used to detect the levels of messenger RNA (mRNA) Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway-related markers.

Results

Higher expression of KCNQ1OT1 was detected in SCLC chemo-resistant verso chemo-sensitive cells. Knockdown of KCNQ1OT1 inhibited SCLC cell viability and cloning ability, hindered cell migration and invasion, induced apoptosis in vitro, and suppressed tumor growth and chemoresistance in vivo, by activating the JAK2/STAT3 signaling pathway.

Conclusions

This is the first study to indicate that lncRNA KCNQ1OT1 promotes cell proliferation and invasion, and prevents apoptosis of SCLC by activating the JAK2/STAT3 pathway.

Exosome-Mediated Transfer of circ_0000338 Enhances 5-Fluorouracil Resistance in Colorectal Cancer through Regulating MicroRNA 217 (miR-217) and miR-485-3p

Exosomes are microvesicles secreted by body cells for intercellular communication. The circular RNA circ_0000338 was found to be present in extracellular vesicles and improve the chemoresistance of colorectal cancer (CRC) cells. However, the role of exosomal circ_0000338 in 5-fluorouracil (5-FU) resistance in CRC is largely unknown. The levels of circ_0000338, microRNA 217 (miR-217), and miR-485-3p were detected using quantitative real-time PCR (qRT-PCR). The 50% inhibitory concentration (IC₅₀) values of cells for 5-FU, cell proliferation, and apoptosis were evaluated using cell counting kit 8 (CCK-8), colony formation, flow cytometry, and Western blot assays. The interaction between miR-217 or miR-485-3p and circ_0000338 was confirmed by RNA immunoprecipitation (RIP), dual-luciferase reporter, and pulldown assays. Exosomes were isolated by ultracentrifugation and qualified by transmission electron microscopy (TEM), Nanosight tracking analysis (NTA), and Western blotting. Xenograft models were performed to analyze whether circ_0000338-loaded exosomes could increase resistance of CRC cells to 5-FU in vivo The circ_0000338 level was elevated in 5-FU-resistant CRC tissues and cells, and circ_0000338 knockdown sensitized 5-FU-resistant CRC cells to 5-FU through enhancing apoptosis and decreasing proliferation in vitro Mechanistically, circ_0000338 directly bound to miR-217 and miR-485-3p, and the inhibition of miR-217 or miR-485-3p reversed the effects of circ_0000338 knockdown on cell 5-FU resistance in CRC. Additionally, extracellular circ_0000338 could be incorporated into secreted exosomes and transmitted to 5-FU-sensitive cells. Treatment-sensitive cells with exosomes containing circ_0000338 reduced the 5-FU response in CRC both in vitro and in vivo Besides that, the exosomal circ_0000338 concentration was higher in patients exhibiting resistance to 5-FU and showed good diagnostic efficiency in 5-FU-resistant CRC. The delivery of circ_0000338 via exosomes enhanced 5-FU resistance in CRC through negative regulation of miR-217 and miR-485-3p, indicating a promising diagnostic and therapeutic marker for 5-FU-based chemotherapy in CRC patients.

KCNQ1OT1 regulates the retinoblastoma cell proliferation, migration and SIRT1/JNK signaling pathway by targeting miR-124/SP1 axis

Objective: Long non-coding RNA (lncRNA) KCNQ1OT1 was reported to be tightly associated with tumorigenesis and progression of multiple cancers. However, the expression and biological functions of KCNQ1OT1 in retinoblastoma (RB) are still unknown. We aim to elucidate the potential function and underlying mechanism of KCNQ1OT1 in regulating the progression of RB. Methods: The levels of KCNQ1OT1 were assayed by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) analysis. The cell proliferation of RB cells (Y79 and WERI-Rb-1) were evaluated through Cell Counting Kit 8 (CCK-8) assay. Meanwhile, Y79 and WERI-Rb-1 cell apoptosis and cell cycle were assessed by Flow Cytometry analysis. Dual luciferase reporter assay were performed to illustrate the interaction between KCNQ1OT1, miR-124, and SP1. Results: We found that KCNQ1OT1 was up-regulated and miR-124 was down-regulated in RB tissues and cells. Moreover, knockdown of KCNQ1OT1 reduced the proliferation, migration, and cell cycle, as well as promoted cell apoptosis of Y79 and WERI-Rb-1 cells. Western blot analysis consistently proved cell cycle and apoptosis related protein expression levels. More importantly, KCNQ1OT1 was a sponge of microRNA (miR)-124. MiR-124 inhibition strongly reversed the effect on cell proliferation, cycle arrest, and apoptosis by KCNQ1OT1 knockdown mediation. In addition, KCNQ1OT1 regulated expression of SP1, a direct target of miR-124 in RB. On the other hand, miR-124 inhibitor abrogated the active effect of KCNQ1OT1 silencing on silent information regulator 1 (SIRT1)/c-Jun N-terminal kinase (JNK) signaling pathway. The function of KCNQ1OT1 was verified in vivo. Conclusions: These findings implied that KCNQ1OT1 silencing inhibited RB progression and activated SIRT1/JNK signaling pathway partially by modulating the miR-124/SP1 axis.

Construction and prognostic analysis of miRNA-mRNA regulatory network in liver metastasis from colorectal cancer

Background

Colorectal cancer (CRC) is one of the most common cancers in the world, and liver metastasis is the leading cause of colorectal cancer-related deaths. However, the mechanism of liver metastasis in CRC has not been clearly elucidated.

Methods

Three datasets from the Gene Expression Omnibus (GEO) database were analyzed to obtain differentially expressed genes (DEGs), which were subjected to functional enrichment analysis and protein-protein interaction analysis. Subsequently, mRNA-miRNA network was constructed, and the associated DEGs and DEMs were performed for prognostic analysis. Finally, we did infiltration analysis of growth arrest specific 1 (GAS1)-associated immune cells.

Results

We obtained 325 DEGs and 9 differentially expressed miRNAs (DEMs) between primary CRC and liver metastases. Enrichment analysis and protein-protein interactions (PPI) further revealed the involvement of DEGs in the formation of the inflammatory microenvironment and epithelial-mesenchymal transition (EMT) during the liver metastases process in CRC. Survival analysis demonstrated that low-expressed GAS1 as well as low-expressed hsa-miR-33b-5p was a favorable prognostic indicator of overall survival. Further exploration of GAS1 revealed that its expression was interrelated with the infiltration of immune cells in tumor tissues.

Conclusions

In summary, DEGs, DEMs, and their interactions found in liver metastasis of CRC may provide a basis for further understanding of the mechanism of CRC metastasis.

LncRNA KCNQ1OT1 acts as miR-216b-5p sponge to promote colorectal cancer progression via up-regulating ZNF146

Long non-coding RNAs (lncRNAs) have shown to act as important regulators in cancer biology. The aim of this study was to investigate the role and mechanism of lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in colorectal cancer (CRC) progression. The abundance of KCNQ1OT1, microRNA-216b-5p (miR-216b-5p) and zinc finger protein 146 (ZNF146) messenger RNA (mRNA) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and colony formation assay. Cell migration and invasion abilities were assessed by transwell assays. Western blot assay was performed for determination of protein levels. LncBase v.2 of DIANA Tool and StarBase software were used to predict the targets of KCNQ1OT1 and miR-216b-5p, respectively. Dual-luciferase reporter assay was implemented to confirm the target interaction between miR-216b-5p and KCNQ1OT1 or ZNF146. KCNQ1OT1 expression was higher in CRC tissues and cell lines. KCNQ1OT1 interference restrained the proliferation, migration and invasion of CRC cells. MiR-216b-5p was a target of KCNQ1OT1 in CRC cells, and KCNQ1OT1 knockdown-induced effects in CRC cells were partly overturned by miR-216b-5p silencing. MiR-216b-5p bound to the 3' untranslated region (3'UTR) of ZNF146, and ZNF146 overexpression partly attenuated miR-216b-5p overexpression-mediated influences in CRC cells. KCNQ1OT1 up-regulated the abundance of ZNF146 through sequestering miR-216b-5p in CRC cells. KCNQ1OT1 accelerated the proliferation and motility of CRC cells through elevating ZNF146 expression via sponging miR-216b-5p. KCNQ1OT1/miR-216b-5p/ZNF146 axis might be underlying target for the diagnosis and treatment of CRC patients.

Long non-coding RNA KCNQ1 overlapping transcript 1 promotes the progression of esophageal squamous cell carcinoma by adsorbing microRNA-133b

OBJECTIVE

The long non-coding RNA (lncRNA) KCNQ1 overlapping transcript 1 (KCNQ1OT1) exerts vital regulatory functions in diverse tumors. However, the biological function of KCNQ1OT1 in esophageal squamous cell carcinoma (ESCC) remains unclear.

METHODS

KCNQ1OT1 expression was detected in ESCC tissues using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, apoptosis, migration, and invasion were detected by the CCK-8 assay, EdU assay, flow cytometry analysis, and Transwell experiments, respectively. Bioinformatics analysis, luciferase reporter experiments, and RNA immunoprecipitation assays were used to predict and validate the regulatory relationships between KCNQ1OT1, microRNA-133b (miR-133b) and epidermal growth factor receptor (EGFR).

RESULTS

KCNQ1OT1 expression was remarkably upregulated in ESCC tissues and cell lines. Overexpression of KCNQ1OT1 markedly promoted ESCC cell proliferation, migration, and invasion and enhanced the expression of N-cadherin, MMP-2, and MMP-9, but inhibited apoptosis and E-cadherin expression in ESCC cell lines; KCNQ1OT1 knockdown exerted the opposite effects. KCNQ1OT1 could directly bind to miR-133b and suppress its expression, and miR-133b reversed the effects of KCNQ1OT1 overexpression in ESCC cells. MiR-133b reduced the expression of epidermal growth factor receptor (EGFR); further, KCNQ1OT1 activated the phosphatidylinositol 3-kinase/AKT serine/threonine kinase 1 (PI3K/AKT) signaling pathway by repressing miR-133b repression and indirectly upregulating EGFR. KCNQ1OT1 expression was positively correlated with EGFR mRNA expression and negatively correlated with miR-133b expression.

CONCLUSION

KCNQ1OT1 facilitates ESCC progression by sponging miR-133b and activating the EGFR/PI3K/AKT pathway.

Association study between KCNQ1 and KCNQ1OT1 genetic polymorphisms and gastric cancer susceptibility and survival in a Chinese Han population: a case-control study

Background

The present study analyzed gene polymorphisms in the potassium voltage-gated channel KQT-like subfamily member 1 (KCNQ1) and the long noncoding RNA, KCNQ1OT1, and their impacts on genetic susceptibility and survival in a Chinese Han population with gastric cancer (GC).

Methods

We designed a case-control study that included 681 patients with GC and 756 healthy controls. Three single-nucleotide polymorphisms (SNPs) in the KCNQ1 gene region and eight SNPs in the KCNQ1OT1 gene region were selected for further research.

Results

Among the 11 SNPs, we found no significant differences in the genotype and allele frequencies between GC patients and the healthy population. Hierarchical analysis by the log-additive model indicated that the KCNQ1 rs231348 CT genotype was significantly associated with an increased GC risk in individuals aged ≥55 years, regardless of gender. The KCNQ1OT1 rs231352 CC and rs7128926 AA genotypes increased the risk of GC in individuals with stage III/IV tumors larger than 5 cm in diameter. On evaluating the genotype polymorphism and survival analysis, we detected that the AA genotypes of the KCNQ1OT1 rs7128926 and rs7939976 polymorphisms presented a significant survival advantage over the GA/GG genotypes, especially in patients with the following characteristics: age >55, Helicobacter pylori infection, BMI >24, tumor in the non-cardia region with a diameter greater than 5 cm, clinical stage II, and postoperative adjuvant chemotherapy.

Conclusions

Our results suggest that the KCNQ1 rs231348 and KCNQ1OT1 rs231352 polymorphisms might be independent predictors of the risk of GC susceptibility depending on certain factors, such as the age of the individual and the tumor stage and diameter. Simultaneously, genotype polymorphism of the rs7128926 and rs7939976 loci of the KCNQ1OT1 gene independently predicted the recurrence-free survival (RFS) and overall survival (OS) of GC patients.

MicroRNA-217: A regulator of human cancer

As highly conserved non-coding RNAs of approximately 18-24 nucleotides, microRNAs (miRNAs) regulate the expression of target genes. Multiple studies have demonstrated that miRNAs participate in the regulation of human cancer. MircoRNA-217 (miR-217) participates in the regulation of various tumors by specifically binding target genes and post-transcriptional regulation. In recent years, there have been numerous reports about miR-217 in tumor progression. MiR-217 is known mainly as a tumor suppressor, although some studies have shown that it functions as an oncomiR. Here, we review the current research related to miR-217, including its role in tumor progression and the molecular mechanisms.

Biomarker Discovery for the Carcinogenic Heterogeneity Between Colon and Rectal Cancers Based on lncRNA-Associated ceRNA Network Analysis

Background

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Emerging evidence has revealed that risk factors and metastatic patterns differ greatly between colon and rectal cancers. However, the molecular mechanism underlying their pathogenic differences remains unclear. Therefore, we here aimed to identify non-coding RNA biomarkers based on lncRNA-associated ceRNA network (LceNET) to elucidate the carcinogenic heterogeneity between colon and rectal cancers.

Methods

A global LceNET in human was constructed by employing experimental evidence-based miRNA-mRNA and miRNA-lncRNA interactions. Then, four context-specific ceRNA networks related to cancer initiation and metastasis were extracted by mapping differentially expressed lncRNAs, miRNAs and mRNAs to the global LceNET. Notably, a novel network-based bioinformatics model was proposed and applied to identify lncRNA/miRNA biomarkers and critical ceRNA triplets for understanding the carcinogenic heterogeneity between colon and rectal cancers. Moreover, the identified biomarkers were further validated by their diagnostic/prognostic performance, expression pattern and correlation analysis.

Results

Based on network modeling, lncRNA KCNQ1OT1 (AUC>0.85) and SNHG1 (AUC>0.94) were unveiled as common diagnostic biomarkers for the initiation and metastasis of colon and rectal cancers. qRT-PCR analysis uncovered that these lncRNAs had significantly higher expression level in CRC cell lines with high metastatic potential. In particular, KCNQ1OT1 and SNHG1 function in colon and rectal cancers via different ceRNA mechanisms. For example, KCNQ1OT1/miR-484/ANKRD36 axis was involved in the initiation of colon cancer, while KCNQ1OT1/miR-181a-5p/PCGF2 axis was implicated in the metastasis of rectal cancer; the SNHG1/miR-484/ORC6 axis played a role in colon cancer, while SNHG1/miR-423-5p/EZH2 and SNHG1/let-7b-5p/ATP6V1F axes participated in the initiation and metastasis of rectal cancer, respectively. In these ceRNA triplets, miR-484, miR-181a-5p, miR-423-5p and let-7b-5p were identified as miRNA biomarkers with excellent distinguishing ability between normal and tumor tissues, and ANKRD36, PCGF2, EZH2 and ATP6V1F were closely related to the prognosis of corresponding cancer.

Conclusion

The landscape of lncRNA-associated ceRNA network not only facilitates the exploration of non-coding RNA biomarkers, but also provides deep insights into the oncogenetic heterogeneity between colon and rectal cancers, thereby contributing to the optimization of diagnostic and therapeutic strategies of CRC.

LncRNA KCNQ1OT1 inhibits the radiosensitivity and promotes the tumorigenesis of hepatocellular carcinoma via the miR-146a-5p/ACER3 axis

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death, and radiotherapy is currently one of the main treatments. Long non-coding RNAs (lncRNAs) are associated with the radiosensitivity and tumorigenesis of HCC. However, the role and molecular mechanism of potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) in HCC are still unclear. The relative expression of KCNQ1OT1, microRNA-146a-5p (miR-146a-5p) and alkaline ceramidase 3 (ACER3) was quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Clonogenic assay was used to assess the radiosensitivity of cells. Cell apoptosis and metastasis were evaluated by flow cytometry and transwell assays, respectively. The protein levels of apoptosis markers, metastasis markers and ACER3 were detected by western blot (WB) analysis. The relationship between miR-146a-5p and KCNQ1OT1 or ACER3 was determined by dual-luciferase reporter assay. Additionally, animal experiments were carried out to explore the effect of KCNQ1OT1 silencing on HCC tumor growth in vivo. KCNQ1OT1 was highly expressed in HCC, and its knockdown hindered the proliferation and metastasis, while increased the radiosensitivity and apoptosis of HCC cells. MiR-146a-5p could interact with KCNQ1OT1, and its inhibition reversed the effects of silenced-KCNQ1OT1 on the radiosensitivity and tumorigenesis of HCC cells. Besides, ACER3 was a target of miR-146a-5p, and its overexpression inversed the effects of miR-146a-5p mimic on the radiosensitivity and tumorigenesis of HCC cells. The expression of ACER3 was regulated by KCNQ1OT1 and miR-146a-5p. Furthermore, KCNQ1OT1 also could reduce the growth of HCC by regulating the miR-146a-5p/ACER3 axis in vivo. Our study suggested that KCNQ1OT1 improved ACER3 expression to regulate the radiosensitivity and tumorigenesis of HCC through sponging miR-146a-5p, indicating that KCNQ1OT1 might be a new therapeutic target for HCC.

LncRNA KCNQ1OT1 knockdown inhibits viability, migration and epithelial-mesenchymal transition in human lens epithelial cells via miR-26a-5p/ITGAV/TGF-beta/Smad3 axis

BACKGROUND

Long noncoding RNA potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) takes part in diabetic cataract progression. This research aims to analyze the function and mechanism of KCNQ1OT1 on viability, migration and epithelial-mesenchymal transition (EMT) in lens epithelial cells.

METHODS

20 diabetic cataract posterior lens capsule tissues and normal samples were collected. Lens epithelial cells (SRA01/04) were stimulated via high glucose (HG). The levels of KCNQ1OT1, miR-26a-5p, integrin αV (ITGAV), TGF-β, Smad3 and phosphorylated (p)-Smad3 were measured via quantitative real-time polymerase chain reaction or Western blot. Cell viability, migration and EMT were analyzed via MTT, wound healing, transwell and Western blot assays. The target relationship between miR-26a-5p and KCNQ1OT1 or ITGAV was determined via luciferase reporter assay.

RESULTS

KCNQ1OT1 was up-regulated and miR-26a-5p level was reduced in diabetic cataract tissues and HG-treated SRA01/04 cells. Silence of KCNQ1OT1 or miR-26a-5p up-regulation repressed cell viability, migration and EMT in SRA01/04 cells stimulated via HG. KCNQ1OT1 could target miR-26a-5p and controlled cell viability, migration and EMT via regulating miR-26a-5p. ITGAV was targeted via miR-26a-5p and positively regulated via KCNQ1OT1. ITGAV overexpression promoted cell viability, migration and EMT in HG-treated SRA01/04 cells, which were mitigated by KCNQ1OT1 silence. KCNQ1OT1 knockdown mitigated HG-induced the activation of TGF-β/Smad3 signaling by regulating miR-26a-5p.

CONCLUSION

KCNQ1OT1 knockdown represses cell viability, migration and EMT through miR-26a-5p/ITGAV/TGF-β/Smad3 axis in SRA01/04 cells under HG condition, providing a new target for the treatment of diabetic cataract.

Long Non-Coding RNA KCNQ1OT1 Promotes Multidrug Resistance in Chordoma by Functioning as a Molecular Sponge of miR-27b-3p and Subsequently Increasing ATF2 Expression

Background

Chordoma, a rare bone tumor, occurs most commonly at the sacrococcygeal and skull base region. To date, chemotherapy is used to treat patients with advanced-stage chordoma. However, multidrug resistance (MDR) greatly hinders the effect of chemotherapy in chordoma. Here, we studied the correlation between KCNQ1OT1 and chemotherapy resistance.

Methods

RT-PCR assay was used to examine KCNQ1OT1, miR-27b-3p, and ATF2 mRNA expression. CCK8 assay was exercised to detect IC₅₀ values of cisplatin in chordoma cells. ATF2 protein expression was detected by Western blot.

Results

KCNQ1OT1 was increased in chemotherapy-resistant patients and cisplatin-resistant cells, and downregulation of KCNQ1OT1 expression weakened MDR in chordoma. In addition, KCNQ1OT1 promoted MDR in chordoma by sponging miR-27b-3p and subsequently increasing ATF2 expression.

Conclusion

KCNQ1OT1 is proved to be strikingly raised in the chemotherapy-resistant group and to promote MDR in chordoma. Our findings demonstrated the role of the KCNQ1OT1/miR-27b-3p/ATF2 axis in MDR of chordoma, which provides new insight into the molecular mechanism of chordoma MDR, and may determine the effect of therapy after receiving chemotherapy by detecting the expression of KCNQ1OT1 in serum.

LncRNA KCNQ1OT1 sponges miR-15a to promote immune evasion and malignant progression of prostate cancer via up-regulating PD-L1

Background

We focused on the KCNQ1OT1/miR-15a/PD-L1 axis and explored its significance in regulating immune evasion and malignant behaviors of prostate cancer (PC) cells.

Methods

The expression levels of KCNQ1OT1, miR-15a, PD-L1, and CD8 in cells or tissues were examined by RT-qPCR, western blot or immunohistochemistry (IHC) assays. The direct regulations between KCNQ1OT1, miR-15a and PD-L1 were validated by luciferase reporter assay. PC cells were co-cultured with CD8⁺ T cells to study the immune evasion. Proliferation, apoptosis, migration and invasion abilities were detected by MTT, flow cytometry, wound healing and Transwell assays, respectively. The cytotoxicity of CD8⁺ T cells was determined by LDH cytotoxicity Kit. Epithelial–mesenchymal transition (EMT) and Ras/ERK signaling markers were evaluated by western blot.

Results

KCNQ1OT1, PD-L1 and CD8 were increased, while miR-15a was decreased in PC tissues. MiR-15a directly bound to the 3′-UTR of PD-L1 and inhibited the expression of PD-L1. Overexpressing miR-15a in PC cells was sufficient to promote cytotoxicity and proliferation, while inhibit apoptosis of CD8⁺ T cells, and also suppressed viability, migration, invasion and EMT while promoted apoptosis of PC cells. The above anti-tumor effects of miR-15a were reversed by overexpressing PD-L1. KCNQ1OT1 sponged miR-15a and released its inhibition on PD-L1. Functionally, KCNQ1OT1 in PC cells was essential for suppressing the cytotoxicity of CD8⁺ T cells and maintaining multiple malignant phenotypes of PC cells. The Ras/ERK signaling was suppressed after overexpressing miR-15a or knocking down KCNQ1OT1.

Conclusions

LncRNA KCNQ1OT1 sponges miR-15a to promote immune evasion and malignant progression of PC via up-regulating PD-L1.

Integration analysis of long non-coding RNA (lncRNA) role in tumorigenesis of colon adenocarcinoma

Background

Colon adenocarcinoma (COAD) is one of the most common gastrointestinal cancers globally. Molecular aberrations of tumor suppressors and/or oncogenes are the main contributors to tumorigenesis. However, the exact underlying mechanisms of COAD pathogenesis are clearly not known yet. In this regard, there is an urgent need to indicate promising potential diagnostic and prognostic biomarkers in COAD patients.

Methods

In the current study, level 3 RNA-Seq and miR-Seq data and corresponding clinical data of colon adenocarcinoma (COAD) were retrieved from the TCGA database. The “limma” package in R software was utilized to indicate the differentially expressed genes. For in silico functional analysis, GO and KEGG signaling pathways were conducted. PPI network was constructed based on the STRING online database by Cytoscape 3.7.2. A ceRNA network was also constructed by “GDCRNATools” package in R software. Kaplan-Meier survival analysis (log-rank test) and ROC curve analysis were used to indicate the diagnostic and prognostic values of the biomarkers.

Results

The differential expression data demonstrated that 2995 mRNAs, 205 lncRNAs, and 345 miRNAs were differentially expressed in COAD. The GO and KEGG pathway analysis indicated that the differentially expressed mRNAs were primarily enriched in canonical processes in cancer. The PPI network showed that the CDKN2A, CCND1, MYC, E2F, CDK4, BRCA2, CDC25B, and CDKN1A proteins were the critical hubs. In addition, the Kaplan-Meier analysis revealed that 215 mRNAs, 14 lncRNAs, and 39 miRNAs were associated with overall survival time in the patients. Also, the ceRNA network data demonstrated that three lncRNAs including MIR17HG, H19, SNHG1, KCNQ1OT1, MALAT1, GAS5, SNHG20, OR2A1-AS1, and MAGI2-AS3 genes were involved in the development of COAD.

Conclusions

Our data suggested several promising lncRNAs in the diagnosis and prognosis of patients with COAD.

Long non-coding RNA KCNQ1OT1 up-regulates CTNND1 by sponging miR-329-3p to induce the proliferation, migration, invasion, and inhibit apoptosis of colorectal cancer cells

Background

Long non-coding RNAs (lncRNAs) have been certified to be involved in the occurrence and growth of diverse cancers, including CRC. The purpose of the research was to explore the effects of lncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) on proliferation, migration, invasion, and apoptosis in CRC cells and its mechanism.

Methods

The levels of KCNQ1OT1 and miR-329-3p were examined by quantitative real-time polymerase chain reaction (qRT-PCR) in CRC tissues and cells. The mRNA and protein levels of catenin delta-1 (CTNND1) were measured by qRT-PCR and western blot analysis, respectively. The targets of KCNQ1OT1 and miR-329-3p were predicted by online software and confirmed by luciferase reporter assay. The cell proliferation, migration, invasion, and apoptosis were examined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), transwell, and apoptosis assay. The expression levels of CyclinD1, Bcl-2, MMP9, Cleaved-casp-3, and E-cadherin in SW480 and LS1034 cells were gauged by western blot analysis. Xenograft tumor model was structured to prove the biological role of KCNQ1OT1 of CRC in vivo.

Results

The levels of KCNQ1OT1 and CTNND1 were significantly increased in CRC tissues and cells. Knockdown of KCNQ1OT1 suppressed proliferation, migration, invasion, and induced apoptosis in CRC cells. Conversely, CTNND1 overexpression reversed the impact of KCNQ1OT1 knockdown on CRC cells. Moreover, CTNND1 was verified as a direct target of miR-329-3p, and miR-329-3p could specially bind to KCNQ1OT1. Also, the down-regulation of KCNQ1OT1 triggered the CRC progress by up-regulating CTNND1 expression in CRC cells. Besides, KCNQ1OT1 knockdown inhibited CRC tumor growth through the miR-329-3p/CTNND1 axis in vivo.

Conclusion

Our results indicated that KCNQ1OT1 could positively regulate CTNND1 expression by sponging miR-329-3p, thereby boosting the progression of CRC. Our findings provided the underlying therapy targets for CRC.

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

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

Long noncoding RNA KCNQ1OT1 promotes colorectal carcinogenesis by enhancing aerobic glycolysis via hexokinase-2

In this study, we investigated the mechanistic role and prognostic significance of the long coding RNA (lncRNA) KCNQ1OT1 in colorectal cancer (CRC). KCNQ1OT1 levels were significantly higher in CRC tissues than adjacent normal colorectal tissues (n=79). High KCNQ1OT1 expression correlated with poorer prognosis in CRC patients. KCNQ1OT1-silenced CRC cells showed reduced proliferation, colony formation, extracellular acidification, and lactate and glucose secretion. This suggests KCNQ1OT1 promotes CRC cell proliferation by increasing aerobic glycolysis. RNA pull-down assays with biotinylated KCNQ1OT1 followed by mass spectrometry analysis showed that KCNQ1OT1 directly binds to hexokinase 2 (HK2). This was confirmed by RNA immunoprecipitation assays using anti-hexokinase 2 antibody. HK2 protein levels were reduced in KCNQ1OT1 knockdown CRC cells, but were restored by treatment with the proteasomal inhibitor MG132. KCNQ1OT1 knockdown CRC cells also showed higher ubiquitinated-HK2 levels, suggesting KCNQ1OT1 enhances aerobic glycolysis by stabilizing HK2. HK2 overexpression in KCNQ1OT1 knockdown CRC cells restored proliferation and aerobic glycolysis. KCNQ1OT1 levels correlated positively with HK2 expression and prognosis in CRC patients. These findings show that KCNQ1OT1 promotes colorectal carcinogenesis by increasing aerobic glycolysis through HK2.

Long noncoding RNA KCNQ1OT1 is correlated with human breast cancer cell development through inverse regulation of hsa-miR-107

In this work, we investigated the expression pattern and regulatory function of long noncoding RNA (lncRNA) KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in breast cancer. We found that KCNQ1OT1 was significantly upregulated in breast cancer cell lines. In lentiviral-transduced BT-549 and HCC1599 cells, KCNQ1OT1 knockdown impaired cancer cell functions, including in vitro proliferation and migration, and in vivo transplant growth. The possible sponging target of KCNQ1OT1, human microRNA-107 (hsa-miR-107), was confirmed to be bound by KCNQ1OT1, and was upregulated in breast cancer cells with KCNQ1OT1 downregulation. Further, hsa-miR-107 knockdown in KCNQ1OT1-downregulated cancer cells reversed its impairing effects on cancer cell proliferation and migration in vitro. Thus, loss of KCNQ1OT1 is associated with functional impairment in breast cancer cells, likely through inverse regulation of its sponging target, hsa-miR-107.

LncRNA KCNQ1OT1 promotes cell proliferation, migration and invasion via regulating miR-129-5p/JAG1 axis in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) is the most deadly cancer worldwide. LncRNA KCNQ1OT1 has been reported to be involved in the progression of various tumors, including NSCLC. However, the precise mechanism of KCNQ1OT1 in NSCLC requires further investigation.

Methods

The expression levels of KCNQ1OT1, miR-129-5p and JAG1 were detected by qRT-PCR or western blot. Kaplan–Meier survival analysis was used to assess the correlation between KCNQ1OT1 expression and the overall survival of NSCLC patients. CCK-8 assay was used to measure cell viability. Cell migration and invasion were detected by transwell assay. The targets of KCNQ1OT1 and miR-129-5p were predicted by bioinformatics, which was confirmed by dual-luciferase reporter assay or pull-down assay.

Results

KCNQ1OT1 expression was significantly enhanced, while miR-129-5p expression was dramatically reduced in NSCLC tissues and cells. Higher KCNQ1OT1 shortened overall survival and was positively associated with tumor stage and lymph node metastasis. KCNQ1OT1 knockdown inhibited proliferation, migration and invasion of NSCLC cells. Inhibition of miR-129-5p attenuated the inhibition of NSCLC cell viability, migration and invasion induced by KCNQ1OT1 knockdown. In addition, JAG1 was confirmed as a target of miR-129-5p. Knockdown of JAG1 reversed the effects of miR-129-5p knockdown on NSCLC progression. KCNQ1OT1 regulated JAG1 expression by sponging miR-129-5p in NSCLC cells.

Conclusion

KCNQ1OT1 induced proliferation, migration and invasion of NSCLC cells by sponging miR-129-5p and regulating JAG1 expression, indicating that KCNQ1OT1 was a therapeutic target for NSCLC.

FNDC3B, Targeted by miR-125a-5p and miR-217, Promotes the Proliferation and Invasion of Colorectal Cancer Cells via PI3K/mTOR Signaling

Background

Fibronectin type III domain containing 3B (FNDC3B) acts as an oncogene in various cancers, and abnormal expression of FNDC3B has been found in colorectal cancer (CRC). Our study aimed to illustrate the role of FNDC3B in CRC development.

Methods

Through RT-qPCR and western blotting assays, the mRNA and protein expressions of target genes were measured. CCK-8 and MTT methods were used to detect cell proliferation. Invasion ability was determined using Transwell assay. TargetScan platform and luciferase reporter gene assay were performed to predict and validate the bindings between FNDC3B and miR-125a-5p or miR-217. Besides, the expression correlation was measured by Pearson's Correlation analysis.

Results

We found that FNDC3B was significantly upregulated in CRC tissues and tumor cell lines, and high expression of FNDC3B predicted a poor survival outcome. The bindings between FNDC3B and miR-125a-5p and miR-217 were respectively at the motifs of CUCAGGG and AUGCAGU. MiR-125a-5p and miR-217 were downregulated in CRC tissues, and both were negatively correlated with FNDC3B expression. Subsequently, the downregulated miR-125a-5p and miR-217 were confirmed as contributors FNDC3B upregulation in CRC. A loss-of-function assay demonstrated that FNDC3B knockdown inhibited the proliferation of CRC cells, while FNDC3B overexpression promoted the proliferation and invasion of tumor cells. Besides, we validated that PI3K/mTOR signaling was involved in the regulation of FNDC3B on the proliferation and invasion of CRC cells.

Conclusion

Generally, our findings demonstrated that FNDC3B facilitated cell proliferation and invasion via PI3K/mTOR signaling, and further promoted CRC progression. The novel miR-125a-5p/FNDC3B and miR-217/FNDC3B axes might be new targets for CRC prognosis and therapy.

LncRNA KCNQ1OT1 sponges miR-34c-5p to promote osteosarcoma growth via ALDOA enhanced aerobic glycolysis

Metabolic switch from oxidative phosphorylation to aerobic glycolysis, which is also called the Warburg effect, is a hallmark of osteosarcoma (OS) and leads to the enhancement of cell chemoresistance, growth, metastasis, and invasion. Emerging evidence indicates that long non-coding RNA (lncRNA) plays a crucial role in the Warburg effect of cancer cells. Here, we report that lncRNA KCNQ1OT1 was upregulated in OS. Meanwhile, functional experiments demonstrated that the KCNQ1OT1 facilitated proliferation and suppressed apoptosis of OS cells. In addition, KCNQ1OT1 contributed to the Warburg effect by stimulating aldolase A (ALDOA) expression. Furthermore, using bioinformatics analysis, luciferase reporter, RNA immunoprecipitation, and RNA pull-down assay, we identified that KCNQ1OT1 functions as a competing endogenous RNA (ceRNA) by sponging miR-34c-5p, which inhibited ALDOA expression by directly targeting its 3'UTR. Taken together, these data identified a key role of KCNQ1OT1 in glucose metabolism reprogramming of OS. Targeting the KCNQ1OT1/miR-34c-5p/ALDOA axis may be a potential therapeutic target in OS treatment.

Knockdown of lncRNA KCNQ1OT1 inhibits glioma progression by regulating miR-338-3p/RRM2

The dysregulated lncRNA play essential roles in glioma development. This study aimed to investigate the role and mechanism of lncRNA potassium voltage-gated channel subfamily Q member 1 opposite strand/ antisense transcript 1 (KCNQ1OT1) in glioma progression. Tumor tissues and adjacent normal samples were collected from 30 glioma patients. The expression levels of lncRNA KCNQ1OT1, microRNA (miR)-338-3p and ribonucleotide reductase M2 (RRM2) were detected by quantitative real-time polymerase chain reaction or western blot analyses. Levels of cell viability, apoptosis, cell migration and invasion in glioma cell lines were determined using cell counting kit-8, flow cytometry with annexin V-FITC and trans-well assays, respectively. The role of KCNQ1OT1 in glioma development in vivo was investigated using a xenograft model. The target association between miR-338-3p and KCNQ1OT1 or RRM2 was validated by luciferase reporter assay. The results found that expression of KCNQ1OT1 was enhanced in glioma tissues and cells, and KCNQ1OT1 knockdown inhibited cell viability, migration and invasion, and xenograft tumor growth, but promoted apoptosis. miR-338-3p was targeted via KCNQ1OT1 and could reverse the effect of KCNQ1OT1 on glioma progression. RRM2 was targeted via miR-338-3p and attenuated the suppressive effect of miR-338-3p on glioma cell viability, migration and invasion. Besides, KCNQ1OT1 overexpression increased RRM2 expression, and this event was weakened via miR-338-3p up-regulation. In conclusion, the present finding suggest that silencing of KCNQ1OT1 can suppress the development and progression of glioma by up-regulating miR-338-3p and down-regulating RRM2.

DLX6-AS1/miR-204-5p/OCT1 positive feedback loop promotes tumor progression and epithelial-mesenchymal transition in gastric cancer

BACKGROUND

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) participate in progression of gastric cancer (GC). Nevertheless, the function and expression level of DLX6-AS1 in GC remain unknown.

METHODS

We explored the sequencing data of DLX6-AS1 downloaded from The Cancer Genome Atlas. The expression of DLX6-AS1, miR-204-5p and OCT1 in 56 GC patients and GC cell lines was quantified by qRT-PCR and western blotting. Furthermore, we performed in vitro functional assays to assess proliferation, invasion and migration of GC cells by knockdown of DLX6-AS1. The expression level of epithelial-mesenchymal transition (EMT)-related genes was also determined by qRT-PCR and western blotting. Actin remodeling was detected by F-actin phalloidin staining. The luciferase reporter assay and chromatin immunoprecipitation assay was utilized to confirm the bioinformatic prediction. The function of the DLX6-AS1/miR-204-5p/OCT1 axis in GC proliferation was clarified by rescue assays.

RESULTS

We first demonstrated that DLX6-AS1 was upregulated in GC tissues and cell lines and was associated with T3/T4 invasion, distant metastasis and poor clinical prognosis. Further functional analysis showed that downregulation of DLX6-AS1 inhibited GC cell proliferation, migration, invasion and EMT in vitro. Mechanistic investigation indicated that DLX6-AS1 acted as a cancer-promoting competing endogenous RNA (ceRNA) by binding miR-204-5p and upregulating OCT1. Moreover, the transcription factor OCT1 was confirmed to enhance DLX6-AS1 expression by targeting the promoter region.

CONCLUSIONS

This study revealed that OCT1-induced DLX6-AS1 promoted GC progression and the EMT via the miR-204-5p/OCT1 axis, suggesting that this lncRNA might be a promising prognostic biomarker and therapeutic target for GC.

Integrative analysis and validation of dysregulated long non-coding RNAs in colon cancer

It is an increasing evidence that long non‐coding RNAs (lncRNAs) are involved in tumour initiation and progression. Here, we analysed RNA‐sequencing data from the Cancer Genome Atlas (TCGA) datasets. Totally, 1176lncRNAs, 245miRNAs and 2081mRNAs were identified to be differentially expressed (DE) in colon cancer tissues compared with normal tissues. CASC21, a novel lncRNA located in 8q24.21 locus, was significantly overexpressed in 30 colon cancer tissues compared with matched normal tissues by qRT‐PCR assay. CASC21 tended to higher expression as the increase of the tumour‐node‐metastasis (TNM) classification. Functionally, CASC21 promoted cell proliferation by regulating cell cycle and enhanced tumour metastasis by epithelial‐mesenchymal transition (EMT) in colon cancer. Mechanism study indicated that CASC21 might be involved in activating WNT/β‐catenin pathway in colon cancer. In addition, we also built a competing endogenous RNA (ceRNNA) network by bioinformatic analysis using TCGA datasets. Together, our results not only provide novel lncRNAs as potential candidates for further study but also prove that CASC21 is an oncogenic regulator through activating WNT/β‐catenin signalling in colon cancer.

LncRNA KCNQ1OT1 affects cell proliferation, apoptosis and fibrosis through regulating miR-18b-5p/SORBS2 axis and NF-ĸB pathway in diabetic nephropathy

BACKGROUND

It has been reported that long non-coding RNAs (lncRNAs) play vital roles in diabetic nephropathy (DN). Our study aims to research the function of lncRNA KCNQ1OT1 in DN cells and the molecular mechanism.

METHODS

Human glomerular mesangial cells (HGMCs) and human renal glomerular endothelial cells (HRGECs) were cultured in high glucose (30 mM) condition as models of DN cells. KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) and miR-18b-5p levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The mRNA and protein levels of Sorbin and SH3 domain-containing protein 2 (SORBS2), Type IV collagen (Col-4), fibronectin (FN), transcriptional regulatory factor-beta 1 (TGF-β1), Twist, NF-κB and STAT3 were measured by qRT-PCR and western blot. Cell viability was detected by cell counting kit-8 (CCK-8) assay for selecting the proper concentration of glucose treatment. Additionally, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry assay were employed to determine cell proliferation and apoptosis, respectively. The targets of KCNQ1OT1 was predicted by online software and confirmed by dual-luciferase reporter assay.

RESULTS

KCNQ1OT1 and SORBS2 were elevated in DN. Both knockdown of KCNQ1OT1 and silencing of SORBS2 restrained proliferation and fibrosis and induced apoptosis in DN cells. Besides, Overexpression of SORBS2 restored the KCNQ1OT1 knockdown-mediate effects on proliferation, apoptosis and fibrosis in DN cells. In addition, miR-18b-5p served as a target of KCNQ1OT1 as well as targeted SORBS2. KCNQ1OT1 knockdown repressed NF-ĸB pathway.

CONCLUSION

KCNQ1OT1 regulated DN cells proliferation, apoptosis and fibrosis via KCNQ1OT1/miR-18b-5p/SORBS2 axis and NF-ĸB pathway.