N6-methyladenosine-modified long non-coding RNA KIF9-AS1 promotes stemness and sorafenib resistance in hepatocellular carcinoma by upregulating SHOX2 expression

BACKGROUND Hepatocellular carcinoma(HCC)is a prevalent and aggressive tumor.Sorafenib is the first-line treatment for patients with advanced HCC,but resistance to sorafenib has become a significant challenge in this therapy.Cancer stem cells play a crucial role in sorafenib resistance in HCC.Our previous study revealed that the long non-coding RNA(lncRNA)KIF9-AS1 is an oncogenic gene in HCC.However,the role of KIF9-AS1 in drug resistance and cancer stemness in HCC remains unclear.Herein,we aimed to investigate the function and mechanism of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC.AIM To describe the role of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC and elucidate the underlying mechanism.METHODS Tumor tissue and adjacent non-cancerous tissue samples were collected from HCC patients.Sphere formation was quantified via a tumor sphere assay.Cell viability,proliferation,and apoptosis were evaluated via Cell Counting Kit-8,flow cytometry,and colony formation assays,respectively.The interactions between the lncRNA KIF9-AS1 and its downstream targets were confirmed via RNA immunoprecipitation and coimmunoprecipitation.The tumorigenic role of KIF9-AS1 was validated in a mouse model.RESULTS Compared with that in normal controls,the expression of the lncRNA KIF9-AS1 was upregulated in HCC tissues.Knockdown of KIF9-AS1 inhibited stemness and attenuated sorafenib resistance in HCC cells.Mechanistically,N6-methyladenosine modification mediated by methyltransferase-like 3/insulin-like growth factor 2 mRNA-binding protein 1 stabilized and increased the expression of KIF9-AS1.Additionally,KIF9-AS1 increased the stability and expression of short stature homeobox 2 by promoting ubiquitin-specific peptidase 1-induced deubiquitination.Furthermore,depletion of KIF9-AS1 alleviated sorafenib resistance in a xenograft mouse model of HCC.CONCLUSION The N6-methyladenosine-modified lncRNA KIF9-AS1 promoted stemness and sorafenib resistance in HCC by upregulating short stature homeobox 2 expression.

Expression and significant roles of the long non-coding RNA CASC19/miR-491-5p/HMGA2 axis in the development of gastric cancer

BACKGROUND Gastric cancer(GC)is a common malignant tumor,long non-coding RNA and microRNA(miRNA)are important regulators that affect tumor proliferation,metastasis and chemotherapy resistance,and thus participate in tumor progression.CASC19 is a new bio-marker which can promote tumor invasion and metastasis.However,the mechanism by which CASC19 affects the progression of GC through miRNA is not clear.AIM To explore the role of the CASC19/miR-491-5p/HMGA2 regulatory axis in GC.METHODS To explore the expression and prognosis of CASC19 in GC through clinical samples,and investigate the effects of inhibiting CASC19 on the proliferation,migration,invasion and other functions of GC cells through cell counting Kit-8(CCK-8),ethynyldeoxyuridine,Wound healing assay,Transwell,Western blot and flow cytometry experiments.The effect of miR-491-5p and HMGA2 in GC were also proved.The regulatory relationship between CASC19 and miR-491-5p,miR-491-5p and HMGA2 were validated through Dual-luciferase reporter gene assay and reverse transcription PCR.Then CCK-8,Transwell,Wound healing assay,flow cytometry and animal experiments verify the role of CASC19/miR-491-5p/HMGA2 regulatory axis.RESULTS The expression level of CASC19 is related to the T stage,N stage,and tumor size of patients.Knockdown of the expression of CASC19 can inhibit the ability of proliferation,migration,invasion and EMT conversion of GC cells,and knocking down the expression of CASC19 can promote the apoptosis of GC cells.Increasing the expression of miR-491-5p can inhibit the proliferation of GC cells,miR-491-5p mimics can inhibit EMT conversion,and promote the apoptosis of GC cells,while decreasing the expression of miR-491-5p can promote the proliferation and EMT conversion and inhibit the apoptosis of GC cells.The expression of HMGA2 in GC tissues is higher than that in adjacent tissues.At the same time,the expression level of HMGA2 is related to the N and T stages of the patients.Reducing the level of HMGA2 can promote cell apoptosis and inhibit the proliferation of GC cells.Cell experiments and animal experiments have proved that CASC19 can regulates the expression of HMGA2 through miR-491-5p,thereby affecting the biological functions of GC.CONCLUSION CASC19 regulates the expression of HMGA2 through miR-491-5p to affect the development of GC.This axis may serve as a potential biomarker and therapeutic target of GC.

Decreased expression of the long non-coding RNA HOXD-AS2 promotes gastric cancer progression by targeting HOXD8 and activating PI3K/Akt signaling pathway

BACKGROUND Long non-coding RNAs(lncRNAs) have been shown to be associated with many tumors. However, the specific mechanism of lncRNAs in the occurrence and development of gastric cancer(GC) has not been fully elucidated.AIM To explore the expression level and molecular mechanism of HOXD-AS2 in GC tissues and cells, and analyze its significance in the prognosis of GC.METHODS Real-time quantitative PCR was used to detect the expression of HOXD-AS2 in 79 pairs of GC tissues and five cell lines. The pc HOXD-AS2 plasmid vector was constructed and transfected into SGC-7901 and SNU-1 GC cells. Matrigel Transwell and wound healing assays were used to confirm the effect of HOXDAS2 on invasion and migration of GC cells. Cell counting kit-8 assay and flow cytometry were used to verify the effect of HOXD-AS2 on the proliferation, cell cycle, and apoptosis of GC cells. The relevant regulatory mechanism between HOXD-AS2 and HOXD8 and PI3K/Akt signaling pathway was verified by Western blot analysis.RESULTS The low expression of lncRNA HOXD-AS2 was associated with lymph node metastasis and tumor-node-metastasis stage in GC. In vitro functional experiments demonstrated that overexpression of HOXD-AS2 inhibited GC cell progression. Mechanistic studies revealed that HOXD-AS2 regulated the expression of its nearby gene HOXD8 and inhibited the activity of the PI3K/Akt signaling pathway.CONCLUSION These results indicate that downregulation of HOXD-AS2 significantly promotes the progression of GC cells by regulating HOXD8 expression and activating the PI3K/Akt signaling pathway. HOXD-AS2 may be a novel diagnostic biomarker and effective therapeutic target for GC.

Expression and mechanism of Long non-coding RNA ASncmtRNA-2 in high glucose treated human renal mesangial cells

Objective:To observe the expression of Long non-coding RNA antisense mitochondrial non-coding RNA-2 (ASncmtRNA-2) in high glucose (HG) treated human renal mesangial cells (HRMCs) and the role of ASncmtRNA-2 in oxidative stress mediated diabetic nephropathy (DN) fibrosis.Methods: The expression levels of ASncmtRNA-2、transforming growth factorβ1 (TGF-β1) and fibronectin (FN) mRNA in cultured HRMCs were measured by qRT-PCR. In addition, relative reactive oxygen species (ROS) levels in HRMCs were detected with the non-fluorescent probe DCFH-DA assays.Results: Compared with 0h, the expression of ASncmtRNA-2 remained unchanged in all groups at 8 h post treatment. However, the level of ASncmtRNA-2 mRNA was increased significantly in HG and HG+NG-nitro-L-Arginine methylester (L-NAME) treated cells compared with low glucose (LG) treated cells from 16h onwards, while the level of ASncmtRNA-2 mRNA in the HG+L-NAME group was decreased compared with the HG group. Moreover, ROS fluorescence was significantly up-regulated in HG-treated cells compared with LG-treated cells, while the ROS fluorescence in HG+L-NAME group was suppressed compared with HG-treated cells. In addition, Levels of ASncmtRNA-2, TGF-β1 and FN mRNA were significantly up-regulated in HG treated cells compared with LG treated cells while Levels of ASncmtRNA-2, TGF-β1 and FN mRNA in HG+L-NAME group were down-regulated compared with HG group. Finally, the expression of ASncmtRNA-2, TGF-β1 and FN mRNA were significantly decreased in HG+ASncmtRNA-2 siRNA group compared with HG group.Conclusion: ASncmtRNA-2 was up-regulated in HG treated cells and may promote glomerular fibrosis in DN via positively regulating the expression of pro-fibrotic factors. These findings may provide novel potential therapeutic treatments for DN.

Expressions of Long Non-Coding RNAs in Carcinogenesis of Cervix: A Review

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides mostly transcribed by RNA which do not encode proteins. Previously, lncRNAs were considered transcriptional byproducts called “junk DNA” with no biological functions. There are many studies conducted on lncRNAs showing they are actively involved in regulation of epigenetic, transcriptional, and post-transcriptional events. Expressions of lncRNAs are more different in many malignant tumors than in benign tumors and normal tissue. Aberration of lncRNAs is responsible to promote or suppress tumorigenesis and cancer progression. Under different circumstances, lncRNAs exhibit their roles in carcinogenesis such as MALAT1 is responsible for intervening mRNA instability, HOTAIR, MALAT1, ANRIL, PVT1 links with miRNA and histonemodifying complexes, MEG3 associates with miRNA, CCAT2, MEG3, GAS5, UCA1 allies with c-Myc or P53 causing suppression of tumor or oncogenesis. Abnormal expressions of lncRNAs are noticed in gynecological cancers, such as cervical cancer, ovarian cancer, and endometrial cancer. Identification of cervical cancer associated lncRNAs is necessary to understand the molecular biogenesis of cancers. In this review, we summarized the foundation and function of the lncRNAs in terms of tumor progression, invasion, prognosis, apoptosis, metastasis, and chemo-resistance. This review will provide references to determine the clinical applications of lncRNAs as ideal diagnostic biomarkers or therapeutic targets in cervical cancers.

LncRNA HCG18 promotes prostate cancer progression by regulating the miR-512-3p/HK-2 axis

ObjectiveLong non-coding RNAs(lncRNAs)play an important role in tumor progression.Numerous studies show that lncRNAs are strongly associated with prostate cancer(PCa)progression.The aim of this study was to investigate the pathway through which lncRNA HCG18 regulates PCa progression by bioinformatics analysis and experiments.MethodsWe compared HCG18 expression in PCa versus normal tissue and cells by data and cell lines,followed by comparing the changes in tumor cell proliferation,migration,and invasive ability after knockdown of HCG18.Then we searched for its downstream pathway by database and validated the pathway in vivo and in vitro.ResultsHCG18 was highly expressed in PCa and has the ability to promote tumor proliferation,migration,and invasion;knockdown of HCG18 led to a decrease in the ability of cells to do so,which can be reversed by knockdown of miR-512-3p or overexpression of hexokinase 2.ConclusionOur in vivo and in vitro experiments suggest that HCG18 can play a role in promoting PCa progression by blocking the inhibition of hexokinase 2 by miR-512-3p via sponge adsorption.

Plant Long ncRNAs: A New Frontier for Gene Regulatory Control

Long non-coding RNA (lncRNA) refers to an over 200 nt functional RNA molecule that will not be translated into protein. Previously thought to be dark matters of the genome, lncRNAs have been gradually recognized as crucial gene regulators. Although tremendous progress has been made in animals and human, the study of lncRNAs in plant is still in its infancy. Here, we reviewed the biogenesis and regulation mechanisms of lncRNAs and summarized the achievements that have been made in plant lncRNA identification and functional characterization. Genome-wide identification has uncovered large amount of lncRNAs in Arabidopsis, Rice, Maize and Wheat, and more information from other plant species will be expected with the aid of deep sequencing technologies. Similar to other species, LncRNA-mediated gene regulation also widely exists in plants, even though only a few functionally characterized examples are available. Up to now, at least four divergent lncRNA-mediated regulation mechanisms have been unraveled, including target mimicry, transcription interference, PRC2 associated histone methylation and DNA methylation. lncRNAs may be involved in the regulation of flowering, male sterility, nutrition metabolism, biotic and abiotic stress response in plants.

The LncRNA FEZF1-AS1 promotes tumor proliferation in colon cancer by regulating the mitochondrial protein PCK2

LncRNAs and metabolism represents two factors involved in cancer initiation and progression.However,the interaction between lncRNAs and metabolism remains to be fully explored.In this study,lncRNA FEZF1-AS1(FEZF1-AS1)was found upregulated in colon cancer after screening all the lncRNAs of colon cancer tissues deposited in TCGA,the result of which was further confirmed by RNAscope staining on a colon tissue chip.The results obtained using FEZF1-AS1 knockout colon cancer cells(SW480 KO and HCT-116 KO)constructed using CRISPR/Cas9 system confirmed the proliferation,invasion,and migration-promoting function of FEZF1-AS1 in vitro.Mechanistically,FEZF1-AS1 associated with the mitochondrial protein phosphoenolpyruvate carboxykinase(PCK2),which plays an essential role in regulating energy metabolism in the mitochondria.Knockdown of FEZF1-AS1 greatly decreased PCK2 protein levels,broke the homeostasis of energy metabolism in the mitochondria,and inhibited proliferation,invasion,and migration of SW480 and HCT-116 cells.PCK2 overexpression in FEZF1-AS1 knockout cells partially rescued the tumor inhibitory effect on colon cancer cells both in vitro and in vivo.Moreover,PCK2 overexpression specifically rescued the abnormal accumulation of Flavin mononucleotide(FMN)and succinate,both of which play an important role in oxidative phosphorylation(OXPHOS).Overall,these results indicate that FEZF1-AS1 is an oncogene through regulating energy metabolism of the cell.This research reveals a new mechanism for lncRNAs to regulate colon cancer and provides a potential target for colon cancer diagnosis and treatment.

Long non-coding RNA HOTAIRM1 promotes proliferation and inhibits apoptosis of glioma cells by regulating the miR-873-5p/ZEB2 axis

Background:Glioblastoma is one of the most common malignant brain tumors.Conventional clinical treatment of glioblastoma is not sufficient,and the molecular mechanism underlying the initiation and development of this disease remains unclear.Our study aimed to explore the expression and function of miR-873a-5p in glioblastoma and related molecular mechanism.Methods:We analyzed the most dysregulated microRNAs from the Gene Expression Omnibus(GEO)database and examined the expression of miR-873-5p in 20 glioblastoma tissues compared with ten normal brain tissues collected in the Zhejiang Tongde Hospital.We then overexpressed or inhibited miR-873-5p expression in U87 glioblastoma cell lines and analyzed the phenotype using the cell counting kit-8 assay,wound healing assay,and apoptosis.In addition,we predicted upstream and downstream genes of miR-873-5p in glioblastoma using bioinformatics analysis and tested our hypothesis in U87 cells using the luciferase reporter gene assay and Western blotting assay.The differences between two groups were analyzed by Student’s t test.The Kruskal-Wallis test was used for the comparison of multiple groups.A P<0.05 was considered to be significant.Results:The miR-873-5p was downregulated in glioblastoma tissues compared with that in normal brain tissues(normal vs.tumor,0.762±0.231 vs.0.378±0.114,t=4.540,P<0.01).Overexpression of miR-873-5p inhibited cell growth(t=6.095,P<0.01)and migration(t=3.142,P<0.01)and promoted cell apoptosis(t=4.861,P<0.01),while inhibition of miR-873-5p had the opposite effect.Mechanistically,the long non-coding RNA HOTAIRM1 was found to act as a sponge of miR-873-5p to activate ZEB2 expression in U87 cells.Conclusions:We uncovered a novel HOTAIRM1/miR-873-5p/ZEB2 axis in glioblastoma cells,providing new insight into glioblastoma progression and a theoretical basis for the treatment of glioblastoma.

Long non-coding RNA LncKdm2b regulates cortical neuronal differentiation by cis-activating Kdm2b

The mechanisms underlying spatial and temporal control of cortical neurogenesis of the brain are largely elusive.Long non-coding RNAs(lncRNAs)have emerged as essential cell fate regulators.Here we found LncKdm2b(also known as Kancr),a lncRNA divergently transcribed from a bidirectional promoter of Kdm2b,is transiently expressed during early differentiation of cortical projection neurons.Interestingly,Kdm2b’s transcription is positively regulated in cis by LncKdm2b,which has intrinsic-activating function and facilitates a permissive chromatin environment at the Kdm2b’s promoter by associating with hnRNPAB.Lineage tracing experiments and phenotypic analyses indicated LncKdm2b and Kdm2b are crucial in proper differentiation and migration of cortical projection neurons.These observations unveiled a lncRNA-dependent machinery in regulating cortical neuronal differentiation.

Long non-coding RNA colon cancer-associated transcript 2:role and function in human cancers

Long non-coding RNAs(lncRNAs)are a family of non-protein-coding RNAs that span a length of over 200 nucleotides.Research reports have illustrated that lncRNAs are involved in various cellular processes and that their abnormal expression leads to the occurrence and development of various tumors.Colon cancer-associated transcript 2(CCAT2)was first reported as an oncogene in colon cancer.LncRNA CCAT2 is abnormally expressed in hepatocellular carcinoma,cholangiocarcinoma,lung cancer,breast cancer,ovarian cancer,glioma,and other tumors.In tumor tissues,abnormally overexpressed CCAT2 can affect cell proliferation,migration,epithelial-mesenchymal transition,apoptosis,and other biological behaviors through endogenous RNAs mechanisms,various signaling pathways,transcriptional regulation,and other complex mechanisms.Additionally,the overexpression of CCAT2 is also closely related to the tumor size,tumor node metastasis(TNM)stage,survival time,and other prognostic factors,suggesting that it is a potential prognostic indicator.This article reviews the biological functions of CCAT2 and its mechanisms of action in tumors from previous studies.In this review,we attempt to provide a molecular basis for future clinical applications of lncRNA CCAT2.

Myogenesis controlled by a long non-coding RNA 1700113A16RIK and post-transcriptional regulation

Long non-coding(lnc)RNA plays important roles in many cellular processes.The function of the vast majority of lncRNAs remains unknown.Here we identified that lncRNA-1700113A16RIK existed in skeletal muscle stem cells(MuSCs)and was significantly elevated during MuSC differentiation.Knockdown of 1700113A16RIK inhibits the differentiation of muscle stem cells.In contrast,overexpression of 1700113A16RIK promotes the differentiation of muscle stem cells.Further study shows the muscle specific transcription factor Myogenin(MyoG)positively regulates the expression of 1700113A16RIK by binding to the promoter region of 1700113A16RIK.Mechanistically,1700113A16RIK may regulate the expression of myogenic genes by directly binding to 3’UTR of an important myogenic transcription factor MEF2D,which in turn promotes the translation of MEF2D.Taken together,our results defined 1700113A16RIK as a positive regulator of MuSC differentiation and elucidated a mechanism as to how 1700113A16RIK regulated MuSC differentiation.