The Function of LncRNA FTX in Several Common Cancers

Construction of an endoplasmic reticulum stress and cuproptosis -related lncRNAs signature in chemosensitivity in hepatocellular carcinoma by comprehensive bioinformatics analysis

Endoplasmic reticulum stress (ERS) and cuproptosis have remarkable effects on hepatocellular carcinoma (HCC) leading to a poor prognosis. The current study aimed to explore credible signature for predicting the prognosis of HCC based on ERS and cuproptosis-related lncRNAs. In our study, clinical and transcriptomic profiles of HCC patients were obtained from the Cancer Genome Atlas (TCGA) database. An ERS and cuproptosis-related lncRNA prognostic signature, including NRAV, SNHG3, LINC00839 and AC004687.1, was determined by correlation tests, Cox regression analysis, least absolute shrinkage, and selection operator (LASSO) methods. Survival and predictive value were evaluated using Kaplan-Meier and receiver operating characteristic (ROC) curves, while calibration and nomograms curves were developed. Besides the enrichment analyses for ERS and cuproptosis-related lncRNAs, mutational status and immune status were assessed with TMB and ESTIMATE. Additionally, consensus cluster analysis was employed to compare cancer subtype differences, while drug sensitivity and immunologic efficacy were evaluated for further exploration. qRT-PCR and CCK-8 were utilized to verify the alteration of the prognostic lncRNAs expression and proliferation in vitro. High-risk groups exhibited poorer prognosis. The signature exhibited robust predictive value as an independent prognostic indicator and showed significant correlation with clinicopathological features. In the enriched analysis, biological membrane pathways were enriched. Low-risk patients had lower TMB and higher immune status. A cluster analysis revealed that cluster 2 had the best clinical immunological efficacy and most active immune function. In brief, our constructed signature with ERS and cuproptosis-related lncRNAs was associated survival outcomes of HCC, and can be used to predict the clinical classification and curative effect.

Mechanism of LncRNA FTX regulates nephroblastoma progression through MiR-215-5p/PI3K/AKT axis

BACKGROUND

Nephroblastoma, also more commonly known as Wilms tumor (WT), is a common childhood malignancy that connects tumorigenesis and organ development in the kidney.

OBJECTIVE

The current study focused on the effect of lncRNA FTX in nephroblastoma.

STUDY DESIGN

Expression of lncRNA FTX in nephroblastoma tissues and cells was determined. The expression location of lncRNA FTX was detected by FISH. The binding of lncRNA FTX and miR-215-5p with Ago2 was verified by RIP. Following gain- and loss-of-function approaches, the crucial role of lncRNA FTX and miR-215-5p in nephroblastoma cell functions was measured with the involvement of the PI3K/AKT pathway.

RESULTS

LncRNA FTX was elevated and miR-215-5p was declined in nephroblastoma. Silencing of lncRNA FTX or mimic of miR-215-5p inhibited the malignant properties of nephroblastoma cells. LncRNA FTX was localized in the cytoplasm and might bind miR-215-5p. LncRNA FTX promoted the malignant features of nephroblastoma cells by inhibiting miR-215-5p through activating of the PI3K/AKT pathway.

CONCLUSIONS

LncRNA FTX is capable of accelerating nephroblastoma development in vitro by reducing miR-215-5p through activating of the PI3K/AKT pathway, indicating LncRNA FTX may possibly a future target for the diagnosis and treatment of nephroblastoma. SUMMARY FIGURE.

The pluripotent factor OCT4A enhances the self-renewal of human dental pulp stem cells by targeting lncRNA FTX in an LPS-induced inflammatory microenvironment

BACKGROUND

Regulating the pluripotency of human dental pulp stem cells (hDPSCs) is key for the self-repair of injured dental pulp. We previously found that OCT4A promotes the proliferation and odontogenic differentiation of human dental pulp cells (hDPCs). Recent studies have shown the interaction between OCT4A and lncRNAs in pluripotency maintenance of various stem cells. The aim of this study was to explore the underlying roles and mechanisms of OCT4A and its related lncRNAs in the proliferation and multidirectional differentiation of hDPSCs in an inflammatory microenvironment.

METHODS

Human lncRNA microarrays were applied to screen out the differentially expressed lncRNAs in hDPSCs between the OCT4A-overexpressing and vector groups. Lipopolysaccharide (LPS) was used to simulate the inflammatory microenvironment. The effects of OCT4A and the lncRNA FTX on the proliferation and multidifferentiation of hDPSCs were observed by the CCK-8 assay, EdU staining, real-time PCR, western blotting, and Alizarin red and oil red O staining. Bioinformatics analysis and chromatin immunoprecipitation (ChIP) assays were performed to clarify the targeted mechanism of OCT4A on FTX. The regulation by FTX of the expression of OCT4A and its downstream pluripotent transcription factors SOX2 and c-MYC was further detected by real-time PCR and western blotting.

RESULTS

The microarray results showed that 978 lncRNAs (250 of which were upregulated and 728 downregulated) were potentially differentially expressed genes (fold change ≥ 2, P < 0.05). LPS stimulation attenuated the self-renewal of hDPSCs. OCT4A enhanced the cell proliferation and multidifferentiation capacities of hDPSCs in an inflammatory microenvironment, while FTX exhibited the opposite effects. OCT4A negatively regulated FTX function by binding to specific regions on the FTX promoter, thereby inhibiting the transcription of FTX. Moreover, overexpression of FTX downregulated the expression of OCT4A, SOX2 and c-MYC, whereas knockdown of FTX facilitated their expression.

CONCLUSIONS

OCT4A was found to be a crucial factor maintaining the self-renewal of hDPSCs by transcriptionally targeting FTX in an inflammatory microenvironment. Moreover, we proposed a novel function of FTX in negatively regulating the pluripotency and multilineage differentiation capacity of hDPSCs. The hierarchical organization between OCT4A and FTX expanded the understanding of the network between transcription factors and lncRNAs in fine-tuning the pluripotency/differentiation balance of adult stem cells, and provided prospective targets for optimizing dental-derived stem cell sources for regenerative endodontics.

Comprehensive analysis of m6A modification lncRNAs in high glucose and TNF-α induced human umbilical vein endothelial cells

N6-methyladenosine (m6A) RNA methylation, as a reversible epigenetic modification of mammalian mRNA, holds a critical role in multiple biological processes. m6A modification in Long non-coding RNAs (lncRNAs) has increasingly attracted more attention in recent years, especially in diabetics, with or without metabolic syndrome. We investigated via m6A-sequencing and RNA-sequencing the differentially expressed m6A modification lncRNAs by high glucose and TNF-α induced endothelial cell dysfunction in human umbilical vein endothelial cells. Additionally, gene ontology and kyoto encyclopedia of genes and genomes analyses were performed to analyze the biological functions and pathways for the target of mRNAs. Lastly, a competing endogenous RNA network was established to further reveal a regulatory relationship between lncRNAs, miRNAs and mRNAs. A total of 754 differentially m6A-methylated lncRNAs were identified, including 168 up-regulated lncRNAs and 266 down-regulated lncRNAs. Then, 119 significantly different lncRNAs were screened out, of which 60 hypermethylated lncRNAs and 59 hypomethylated lncRNAs. Moreover, 122 differentially expressed lncRNAs were filtered, containing 14 up-regulated mRNAs and 18 down-regulated lncRNAs. Gene ontology and kyoto encyclopedia of genes and genomes analyses analyses revealed these targets were mainly associated with metabolic process, HIF-1 signaling pathway, and other biological processes. The competing endogenous RNA network revealed the regulatory relationship between lncRNAs, miRNAs and mRNAs, providing potential targets for the treatment and prevention of diabetic endothelial cell dysfunction. This comprehensive analysis for lncRNAs m6A modification in high glucose and TNF-α-induced human umbilical vein endothelial cells not only demonstrated the understanding of characteristics of endothelial cell dysfunction, but also provided the new targets for the clinical treatment of diabetes. Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval will not be required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

Quantitative proteomics analysis revealed the potential role of lncRNA Ftx in cardiomyocytes

OBJECTIVE

This study aims to decode the proteomic signature of cardiomyocytes in response to lncRNA Ftx knockdown and overexpression via proteomic analysis, and to study the biological role of lncRNA Ftx in cardiomyocytes.  METHODS: The expression level of the lncRNA Ftx in cardiomyocytes cultured in vitro was intervened, and the changes in protein levels in cardiomyocytes were quantitatively detected by liquid chromatography-mass spectrometry. The key molecules and pathways of the lncRNA-Ftx response were further examined by GO, KEGG, and protein interaction analysis.

RESULTS

A total of 2828 proteins are quantified. With a 1.5-fold change threshold, 32 upregulated proteins and 49 downregulated proteins are identified in the lncRNA Ftx overexpression group, while 67 up-regulated proteins and 54 down-regulated proteins are identified in the lncRNA Ftx knockdown group. Functional clustering analysis of differential genes revealed that the lncRNA Ftx is involved in regulating cardiomyocyte apoptosis and ferroptosis and improving cellular energy metabolism. In addition, Hub genes such as ITGB1, HMGA2, STAT3, GSS, and LPCAT3 are regulated downstream by lncRNA Ftx.

CONCLUSION

This study demonstrates that lncRNA Ftx plays a vital role in cardiomyocytes and may be involved in the occurrence and development of various myocardial diseases. It provides a potential target for clinical protection of the myocardium and reversal of myocardial fibrosis.

A pan-cancer analysis of the prognostic value of long non-coding RNA LINC00662 in human cancers

Background: Numerous studies have revealed that the long non-coding RNA LINC00662 is irregularly expressed in various cancers, as well as is correlated with cancer development and progression. Nevertheless, the clinical value of LINC00662 remains controversial. Hence, we explored the correlation of LINC00662 with cancer prognosis through meta-analysis and bioinformatics analysis. Methods: From the beginning through 12 March 2022, we searched for correlational studies on Web of Science, Embase, PubMed and The Cochrane Library. We used pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) to determine the significance of studies on survival outcomes and clinicopathological aspects in human cancers. Additionally, the Gene Expression Profiling Interactive Analysis (GEPIA) database was employed to confirm our findings. Results: Our meta-analysis of 14 studies comprising a total of 960 cancer patients revealed that LINC00662 overexpression was correlated with poor overall survival (HR = 1.91, 95% CI 1.49-2.45, p < 0.001) in cancer patients and relapse-free survival (HR = 2.12, 95% CI 1.19-3.76, p = 0.010) in hepatocellular carcinoma patients. The correlation between LINC00662 and OS was further supported by the results of subgroup analyses according to cancer type, follow-up time, HR availability, and NOS score. In addition, LINC00662 overexpression predicted advanced tumor stage (OR = 4.23, 95% CI 2.50-7.17, p < 0.001), larger tumor size (OR = 1.49, 95% CI 1.11-1.99, p = 0.008), earlier lymph node metastasis (OR = 2.40, 95% CI 1.25-4.59, p = 0.008), and earlier distant metastasis (OR = 4.78, 95% CI 2.57-8.88, p < 0.001). However, there were no statistically significant differences in age (OR = 1.16, 95% CI 0.90-1.51, p = 0.246), gender (OR = 1.10, 95% CI 0.79-1.53, p = 0.578), or differentiation grade (OR = 1.53, 95% CI 0.71-3.33, p = 0.280). Conclusion: LINC00662 expression upregulation is associated with poor prognosis and advanced clinicopathological features in patients with multiple tumors. LINC00662 may serve as a biomarker for the diagnosis and treatment of patients with tumors.

Analysis of long non-coding RNA expression profile of bovine monocyte-macrophage infected by Mycobacterium avium subsp. paratuberculosis

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis. As a potential zoonotic pathogen, MAP also seriously threatens human health and social security. At present, long non-coding RNA (lncRNA) has attracted wide attention as an useful biomarker in various diseases. Therefore, our study analyzed the lncRNA expression profiles and lncRNA-mRNA regulatory network of MAP infected bovine monocytes-macrophages and uninfected bovine cells by high-throughput sequencing. A total of 4641 differentially expressed lncRNAs genes were identified, including 3111 up-regulated genes and 1530 down-regulated genes. In addition, lncRNA-mRNA interaction analysis was performed to predict the target genes of lncRNA. Among them, after MAP infection, 86 lncRNAs targeted to mRNA, of which only 6 genes were significantly different. The results of Gene Ontology (GO) enrichment analysis showed that the differentially expressed genes significantly enriched in functional groups were related to immune regulation. Multiple signal pathways including NF-κB, NOD-like receptor, Cytokine-cytokine receptor, Toll-like receptor signaling pathway, Chemokine signaling pathway, and other important biochemical, metabolic and signal transduction pathways were enriched in Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, analysis of macrophage transcriptomes in response to MAP infection is expected to provide key information to deeply understand role of the pathogen in initiating an inappropriate and persistent infection in susceptible hosts and molecular mechanisms that might underlie the early phases of paratuberculosis.

Overexpressed lncRNA FTX promotes the cell viability, proliferation, migration and invasion of renal cell carcinoma via FTX/miR‑4429/UBE2C axis

The present study aimed to explore the role of long non‑coding (lnc)RNA FTX and ubiquitin‑conjugating enzyme E2C (UBE2C) in promoting the progression of renal cell carcinoma (RCC) and the underlying regulatory mechanism. Relative levels of lncRNA FTX, UBE2C, AKT, CDK1 and CDK6 in RCC cell lines were detected by reverse transcription‑quantitative (RT‑q). Expression levels of UBE2C, phosphorylated (p)‑AKT/AKT, p‑CDK1/CDK1 and p‑CDK6/CDK6 in RCC and paracancerous specimens and RCC cells were measured by western blot or immunohistochemistry assay. In addition, the proliferative rate, cell viability, cell cycle progression, migratory rate and invasive rate of RCC cells overexpressing lncRNA FTX by lentivirus transfection were determined by a series of functional experiments, including the colony formation assay, MTT assay, flow cytometry, Transwell assay and wound healing assay. The targeted binding relationship in the lncRNA FTX/miR‑4429/UBE2C axis was validated by dual‑luciferase reporter assay. By intervening microRNA (miR)‑4492 and UBE2C by the transfection of miR‑4429‑mimics or short interfering UBE2C‑2, the regulatory effect of lncRNA FTX/miR‑4429/UBE2C axis on the progression of RCC was evaluated. Finally, a xenograft model of RCC in nude mice was established by subcutaneous implantation, thus evaluating the in vivo function of lncRNA FTX in the progression of RCC. The results showed that lncRNA FTX and UBE2C were upregulated in RCC specimens and cell lines. The overexpression of lncRNA FTX in RCC cells upregulated UBE2C. In addition, the overexpression of lncRNA FTX promoted the cell viability and proliferative, migratory and invasive capacities of RCC cells and accelerated the cell cycle progression. A dual‑luciferase reporter assay validated that lncRNA FTX exerted the miRNA sponge effect on miR‑4429, which was bound to UBE2C 3'UTR. Knockdown of UBE2C effectively reversed the regulatory effects of overexpressed lncRNA FTX on the abovementioned phenotypes of RCC cells. In the xenograft model of RCC, the mice implanted with RCC cells overexpressing lncRNA FTX showed a larger tumor size and higher tumor weight than those of controls, while the in vivo knockdown of UBE2C significantly reduced the size of RCC lesions, indicating the reversed cancer‑promoting effect of lncRNA FTX. Overall, the present study showed that lncRNA FTX was upregulated in RCC and could significantly promote the proliferative, migratory and invasive capacities, enhancing the viability and accelerating the cell cycle progression of RCC cells by exerting the miRNA sponge effect on miR‑4429 and thus upregulating UBE2C. lncRNA FTX and UBE2C are potential molecular biomarkers and therapeutic targets of RCC.

Long noncoding RNAs in hepatitis B virus replication and oncogenesis

Several diverse long noncoding RNAs (lncRNAs) have been identified to be involved in hepatitis B virus (HBV) replication and oncogenesis, especially those dysregulated in HBV-related hepatocellular carcinoma (HCC). Most of these dysregulated lncRNAs are modulated by the HBV X protein. The regulatory mechanisms of some lncRNAs in HBV replication and oncogenesis have been characterized. Genetic polymorphisms of several lncRNAs affecting HBV replication or oncogenesis have also been studied. The prognosis of HCC remains poor. It is important to identify novel tumor markers for early diagnosis and find more therapeutic targets for effective treatments of HCC. Some dysregulated lncRNAs in HBV-related HCC may become biomarkers for early diagnosis and/or the therapeutic targets of HCC. This mini-review summarizes these findings briefly, focusing on recent developments.

Identification and Validation of an Endoplasmic Reticulum Stress-Related lncRNA Signature for Colon Adenocarcinoma Patients

Purpose

Methods

Results

Conclusion

Long Non-Coding RNA SNHG6 Supports Glioma Progression Through Upregulation of Notch1, Sox2, and EMT

Gliomas, particularly the advanced grade glioblastomas, have poor 5-year survival rates and worse outcomes. lncRNAs and EMT have been extensively studied in gliomas but the disease progression remains poorly understood. SNHG6 has been shown to affect glioma cell proliferation but its effect on EMT of glioma cells along with its effect on disease progression is not known. We screened four glioma cell lines; H4, A172, U87MG, and SW088 and grouped them based on high vs. low SNHG6 expression. Transfections with SNHG6 specific siRNA resulted in induction of apoptosis of high SNHG6 expressing A172 and U87MG cells. This was accompanied by inhibition of EMT and downregulation of EMT-modulating factor Notch1, β-catenin activity and the cancer stem cell marker Sox2. The regulation was not found to be reciprocal as silencing of Notch1 and Sox2 failed to affect SNHG6 levels. The levels of SNHG6 and Notch1 were also found elevated in Grade IV glioma patients (n = 4) relative to Grade II glioma patients (n = 5). These results identify SNHG6 and Notch1 as valid targets for glioma therapy.

Long non-coding RNA FTX predicts a poor prognosis of human cancers: a meta-analysis

Background: Several studies have assessed the relationship between long non-coding RNA five prime to Xist (FTX) expression, clinicopathological features, and survival outcomes in patients with cancer with conflicting results. This meta-analysis synthesized existing data to clarify the association between FTX with cancer prognosis.

Methods: PubMed, Embase, Cochrane library, Web of Science, Chinese CNKI, and the Chinese WanFang databases were used to search for relevant studies. The role of FTX in cancers was evaluated by pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs).

Results: Eleven studies comprising 1210 participants including colorectal cancer (CRC), hepatocellular carcinoma (HCC), gastric cancer (GC), renal cell carcinoma (RCC), osteosarcoma (OSC), and glioma were enrolled in this analysis. The meta-analysis showed that high FTX expression was significantly associated with several clinicopathological characteristics, including lymph node metastasis in patients with CRC, GC, HCC, and RCC, distant metastasis in patients with CRC, GC, HCC, and OSC, larger tumor size in patients with CRC, GC, HCC, RCC, and OSC, and subsequently TNM/clinical stage in patients with CRC, GC, HCC, OSC, and glioma. The pooled results from the survival analysis revealed a significant correlation between high FTX expression and shorter OS in patients with HCC, CRC, GC, OSC, and glioma. Further, FTX overexpression could be an independent predictive marker for shorter OS in patients with CRC, HCC, OSC, and glioma.

Conclusions: FTX may be a potential oncogene, with high FTX expression being associated with a poorer prognosis in patients with CRC, HCC, OSC, and glioma.

LncRNA FTX Regulates Angiogenesis Through miR-342-3p/SPI1 Axis in Stroke

BACKGROUND

Long non-coding RNAs (lnc-RNAs) and microRNAs (miRNAs) play key roles in the development of stroke. However, the role of lncRNA FTX in stroke is limited known.

METHODS

Real-time polymerase chain reaction (real-time PCR) assays were used to measure the expression of lncRNA FTX, miR-342-3p and SPI1. Western blot assays were employed to examine SPI1 protein expression. The cell viability was measured by CCk8 assay. Cell migration was detected by wound healing assays and transwell assays. Angiogenesis was evaluated by matrigel tube formation assays. The interaction between lncRNA FTX, miR-342-3p and SPI1 was confirmed by site-directed mutagenesis and luciferase assays.

RESULTS

The expression of lncRNA FTX was down-regulated in blood sample from stroke patients, MAO mice tissues and OGD/R treated BMECs. Overexpression of lncRNA FTX could increase the cell viability, migration and angiogenesis in OGD/R treated BMECs. LncRNA FTX could act as a ceRNA for miR-342-3p. Furthermore, miR-342-3p inhibition increased migration and angiogenesis in OGD/R-induced BMECs. Dual-luciferase reporter assay verified that SPI1 was a target of miR-342-3p.

CONCLUSION

In summary, lncRNA FTX enhanced the angiogenesis in stroke by acting as a sponge of miR-342-3p to regulate the expression of SPI1 level.