Methylation-mediated LINC00261 suppresses pancreatic cancer progression by epigenetically inhibiting c-Myc transcription

An anti-sense lncRNA of the A-FABP gene regulates the proliferation of hair follicle stem cells via the chi-miR-335-5p/DKK1/β-catenin axis

Hair follicle development relies on both the epithelial-mesenchymal interaction (EMI) and the proliferation of hair follicle stem cells (HFSCs). This intricate process involves numerous regulatory molecules. Increasing evidence suggests that long non-coding RNAs (lncRNAs) play a crucial role in hair follicle development. However, the functions and molecular mechanisms of many lncRNAs in hair follicle development of cashmere goats remain unclear. Based on our previous lncRNA sequencing results in cashmere goats, an unannotated lncRNA differentially expressed at various stages of hair follicle development, named FABP_AS, was detected. Consequently, we aimed at exploring the function and molecular mechanisms of FABP_AS. We constructed a CRISPR/Cas9 knockout system to specifically knock down FABP_AS, providing a reference model for target lncRNA knockout in animal primary cells. Functional experiment results demonstrated that FABP_AS significantly inhibited HFSCs proliferation. Mechanism experiment results revealed that FABP_AS competitively bond to chi-miR-335-5p, promoted DKK1 gene expression, and reduced Wnt/β-catenin signaling pathway activity. In summary, our findings indicated that FABP_AS acted as a miRNA sponge, sequestering chi-miR-335-5p away from the DKK1 gene, thereby suppressing HFSCs proliferation, which would lay the groundwork for a better understanding of the molecular mechanisms of hair follicle development and provide therapeutic targets for hair loss.

LncRNA LINC00261 associates with chemoresistance and clinical prognosis in patients with epithelial ovarian cancer

OBJECTIVE

The purpose of this experiment is to explore the role of long intergenic noncoding RNA 261 (LINC00261) gene in the chemoresistance and clinical prognosis of epithelial ovarian cancer (EOC).

METHODS

We used matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry to detect the methylation levels of the LINC00261 promoter region in EOC patient specimens. The expression levels of LINC00261, miR-545-3p, and MT1M in EOC patients were evaluated by quantitative real-time reverse transcriptase PCR (RT-qPCR). Spearman's correlation analysis was used for relevance analyses and clinical prognosis was counted by Kaplan-Meier analysis. Stable overexpressed LINC00261 SKOV3 cells were established to test the influence of LINC00261 on proliferation, platinum sensitivity, migration, and invasion.

RESULTS

The promoter region methylation level of the LINC00261 was hypermethylated and LINC00261 was significantly downregulated in platinum-resistant EOC tissues. The methylation level of LINC00261was significantly negative correlated with its RNA expression in EOC. Moreover, hypermethylation and lower expression of LINC00261 in EOC patients were related to shorter progression-free survival (PFS) and overall survival (OS). Furthermore, Spearman's correlation analysis showed that the expression of miR-545-3p had a negative relevance with LINC00261. According to the website prediction, MT1M might be the downstream target gene of LINC00261. Expression of MT1M was negatively correlated with miR-545-3p and positively with LINC00261 in EOC tissues. And lower MT1M mRNA expression was correlated with chemotherapy resistance and worse prognosis. In vitro, overexpression of LINC00261 could inhibit cisplatin resistance, proliferation, and suppression of migration and invasion in SKOV3 cells.

CONCLUSIONS

This research indicates that the aberrant hypermethylation and low expression of LINC00261 were associated with platinum resistance and adverse outcomes in EOC patients.

The dopamine receptor D1 inhibitor, SKF83566, suppresses GBM stemness and invasion through the DRD1-c-Myc-UHRF1 interactions

BACKGROUND

Extensive local invasion of glioblastoma (GBM) cells within the central nervous system (CNS) is one factor that severely limits current treatments. The aim of this study was to uncover genes involved in the invasion process, which could also serve as therapeutic targets. For the isolation of invasive GBM cells from non-invasive cells, we used a three-dimensional organotypic co-culture system where glioma stem cell (GSC) spheres were confronted with brain organoids (BOs). Using ultra-low input RNA sequencing (ui-RNA Seq), an invasive gene signature was obtained that was exploited in a therapeutic context.

METHODS

GFP-labeled tumor cells were sorted from invasive and non-invasive regions within co-cultures. Ui-RNA sequencing analysis was performed to find a gene cluster up-regulated in the invasive compartment. This gene cluster was further analyzed using the Connectivity MAP (CMap) database. This led to the identification of SKF83566, an antagonist of the D1 dopamine receptor (DRD1), as a candidate therapeutic molecule. Knockdown and overexpression experiments were performed to find molecular pathways responsible for the therapeutic effects of SKF83566. Finally, the effects of SKF83566 were validated in orthotopic xenograft models in vivo.

RESULTS

Ui-RNA seq analysis of three GSC cell models (P3, BG5 and BG7) yielded a set of 27 differentially expressed genes between invasive and non-invasive cells. Using CMap analysis, SKF83566 was identified as a selective inhibitor targeting both DRD1 and DRD5. In vitro studies demonstrated that SKF83566 inhibited tumor cell proliferation, GSC sphere formation, and invasion. RNA sequencing analysis of SKF83566-treated P3, BG5, BG7, and control cell populations yielded a total of 32 differentially expressed genes, that were predicted to be regulated by c-Myc. Of these, the UHRF1 gene emerged as the most downregulated gene following treatment, and ChIP experiments revealed that c-Myc binds to its promoter region. Finally, SKF83566, or stable DRD1 knockdown, inhibited the growth of orthotopic GSC (BG5) derived xenografts in nude mice.

CONCLUSIONS

DRD1 contributes to GBM invasion and progression by regulating c-Myc entry into the nucleus that affects the transcription of the UHRF1 gene. SKF83566 inhibits the transmembrane protein DRD1, and as such represents a candidate small therapeutic molecule for GBMs.

Association of LncRNA PCBP1-AS1 with cancer occurrence and development: A review

Long-stranded noncoding RNAs (LncRNAs) are noncoding RNAs >200 nucleotides in length. Polycytidine binding protein 1 antisense LncRNA is abbreviated as LncRNA polycytosine binding protein 1 antisense1 (PCBP1-AS1). Since studies in recent years have revealed the importance of PCBP1-AS1 in human genetic analysis, it is an important member of the LncRNA family. Genetically engineered group analysis of PCBP1-AS1 regulates the progression of cancer in biology. Therefore, it may be an important RNA in the regulation of human cancer. This article summarizes the molecular mechanism and clinical role of PCBP1-AS1 in various tumor types. Taking "PCBP1-AS1" and "cancer" as keywords, this paper analyzed the relationship between PCBP1-AS1 and various tumors by searching PubMed and Geen Medical, and summarized the related regulatory mechanism of PCBP1-AS1. PCBP1-AS1 is a valuable tumor-associated LncRNA that plays different biological roles in different cancers. Overall, it can both promote and inhibit the development of cancer. For example, abnormally high expression in castration-resitant prostate cancer, hepatocellular carcinoma, cervical cancer, glioma, and colorectal cancer promotes the proliferation and progression of these cancers; in contrast, PCBP1-AS1 inhibits cancer proliferation, metastasis, invasion, and recurrence when highly expressed in vulvar squamous cell carcinoma, Hodgkin lymphoma, and lung adenocarcinoma. PCBP1-AS1 regulates the development of multiple tumors, and the specific mechanism needs to be further investigated, which may become a new tumor marker and potential therapeutic target.

Roles of lncRNAs in pancreatic ductal adenocarcinoma: Diagnosis, treatment, and the development of drug resistance

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, primarily due to its late diagnosis, high propensity to metastasis, and the development of resistance to chemo-/radiotherapy. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) are intimately involved in the treatment resistance of pancreatic cancer cells via interacting with critical signaling pathways and may serve as potential diagnostic/prognostic markers or therapeutic targets in PDAC.

DATA SOURCES

We carried out a systematic review on lncRNAs-based research in the context of pancreatic cancer and presented an overview of the updated information regarding the molecular mechanisms underlying lncRNAs-modulated pancreatic cancer progression and drug resistance, together with their potential value in diagnosis, prognosis, and treatment of PDAC. Literature mining was performed in PubMed with the following keywords: long non-coding RNA, pancreatic ductal adenocarcinoma, pancreatic cancer up to January 2022. Publications relevant to the roles of lncRNAs in diagnosis, prognosis, drug resistance, and therapy of PDAC were collected and systematically reviewed.

RESULTS

LncRNAs, such as HOTAIR, HOTTIP, and PVT1, play essential roles in regulating pancreatic cancer cell proliferation, invasion, migration, and drug resistance, thus may serve as potential diagnostic/prognostic markers or therapeutic targets in PDAC. They participate in tumorigenesis mainly by targeting miRNAs, interacting with signaling molecules, and involving in the epithelial-mesenchymal transition process.

CONCLUSIONS

The functional lncRNAs play essential roles in pancreatic cancer cell proliferation, invasion, migration, and drug resistance and have potential values in diagnosis, prognostic prediction, and treatment of PDAC.

Oncogenic signaling pathways in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common (∼90% cases) pancreatic neoplasm and one of the most lethal cancer among all malignances. PDAC harbor aberrant oncogenic signaling that may result from the multiple genetic and epigenetic alterations such as the mutation in driver genes (KRAS, CDKN2A, p53), genomic amplification of regulatory genes (MYC, IGF2BP2, ROIK3), deregulation of chromatin-modifying proteins (HDAC, WDR5) among others. A key event is the formation of Pancreatic Intraepithelial Neoplasia (PanIN) that often results from the activating mutation in KRAS. Mutated KRAS can direct a variety of signaling pathways and modulate downstream targets including MYC, which play an important role in cancer progression. In this review, we discuss recent literature shedding light on the origins of PDAC from the perspective of major oncogenic signaling pathways. We highlight how MYC directly and indirectly, with cooperation with KRAS, affect epigenetic reprogramming and metastasis. Additionally, we summarize the recent findings from single cell genomic approaches that highlight heterogeneity in PDAC and tumor microenvironment, and provide molecular avenues for PDAC treatment in the future.

Target c-Myc to treat pancreatic cancer

C-Myc overexpression is a common finding in pancreatic cancer and predicts the aggressive behavior of cancer cells. It binds to the promoter of different genes, thereby regulating their transcription. C-Myc is downstream of KRAS and interacts with several oncogenic and proliferative pathways in pancreatic cancer. C-Myc enhances aerobic glycolysis in cancer cells and regulates glutamate biosynthesis from glutamine. It provides enough energy for cancer cells' metabolism and sufficient substrate for the synthesis of organic molecules. C-Myc overexpression is associated with chemoresistance, intra-tumor angiogenesis, epithelial-mesenchymal transition (EMT), and metastasis in pancreatic cancer. Despite its title, c-Myc is not "undruggable" and recent studies unveiled that it can be targeted, directly or indirectly. Small molecules that accelerate c-Myc ubiquitination and degradation have been effective in preclinical studies. Small molecules that hinder c-Myc-MAX heterodimerization or c-Myc/MAX/DNA complex formation can functionally inhibit c-Myc. In addition, c-Myc can be targeted through transcriptional, post-transcriptional, and translational modifications.

Insights into the role of long non-coding RNAs in DNA methylation mediated transcriptional regulation

DNA methylation is one of the most important epigenetic mechanisms that governing regulation of gene expression, aberrant DNA methylation patterns are strongly associated with human malignancies. Long non-coding RNAs (lncRNAs) have being discovered as a significant regulator on gene expression at the epigenetic level. Emerging evidences have indicated the intricate regulatory effects between lncRNAs and DNA methylation. On one hand, transcription of lncRNAs are controlled by the promoter methylation, which is similar to protein coding genes, on the other hand, lncRNA could interact with enzymes involved in DNA methylation to affect the methylation pattern of downstream genes, thus regulating their expression. In addition, circular RNAs (circRNAs) being an important class of noncoding RNA are also found to participate in this complex regulatory network. In this review, we summarize recent research progress on this crosstalk between lncRNA, circRNA, and DNA methylation as well as their potential functions in complex diseases including cancer. This work reveals a hidden layer for gene transcriptional regulation and enhances our understanding for epigenetics regarding detailed mechanisms on lncRNA regulatory function in human cancers.

Computational recognition of LncRNA signatures in tumor-associated neutrophils could have implications for immunotherapy and prognostic outcome of non-small cell lung cancer

Cancer immune function and tumor microenvironment are governed by long noncoding RNAs (lncRNAs). Nevertheless, it has yet to be established whether lncRNAs play a role in tumor-associated neutrophils (TANs). Here, a computing framework based on machine learning was used to identify neutrophil-specific lncRNA with prognostic significance in squamous cell carcinoma and lung adenocarcinoma using univariate Cox regression to comprehensively analyze immune, lncRNA, and clinical characteristics. The risk score was determined using LASSO Cox regression analysis. Meanwhile, we named this risk score as “TANlncSig.” TANlncSig was able to distinguish between better and worse survival outcomes in various patient datasets independently of other clinical variables. Functional assessment of TANlncSig showed it is a marker of myeloid cell infiltration into tumor infiltration and myeloid cells directly or indirectly inhibit the anti-tumor immune response by secreting cytokines, expressing immunosuppressive receptors, and altering metabolic processes. Our findings highlighted the value of TANlncSig in TME as a marker of immune cell infiltration and showed the values of lncRNAs as indicators of immunotherapy.

Characterization of sialylation-related long noncoding RNAs to develop a novel signature for predicting prognosis, immune landscape, and chemotherapy response in colorectal cancer

Aberrant sialylation plays a key biological role in tumorigenesis and metastasis, including tumor cell survival and invasion, immune evasion, angiogenesis, and resistance to therapy. It has been proposed as a possible cancer biomarker and a potential therapeutic target of tumors. Nevertheless, the prognostic significance and biological features of sialylation-related long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) remain unclear. This study aimed to develop a novel sialylation-related lncRNA signature to accurately evaluate the prognosis of patients with CRC and explore the potential molecular mechanisms of the sialylation-related lncRNAs. Here, we identified sialylation-related lncRNAs using the Pearson correlation analysis on The Cancer Genome Atlas (TCGA) dataset. Univariate and stepwise multivariable Cox analysis were used to establish a signature based on seven sialylation-related lncRNAs in the TCGA dataset, and the risk model was validated in the Gene Expression Omnibus dataset. Kaplan-Meier curve analysis revealed that CRC patients in the low-risk subgroup had a better survival outcome than those in the high-risk subgroup in the training set, testing set, and overall set. Multivariate analysis demonstrated that the sialylation-related lncRNA signature was an independent prognostic factor for overall survival, progression-free survival, and disease-specific survival prediction. The sialylation lncRNA signature-based nomogram exhibited a robust prognostic performance. Furthermore, enrichment analysis showed that cancer hallmarks and oncogenic signaling were enriched in the high-risk group, while inflammatory responses and immune-related pathways were enriched in the low-risk group. The comprehensive analysis suggested that low-risk patients had higher activity of immune response pathways, greater immune cell infiltration, and higher expression of immune stimulators. In addition, we determined the sialylation level in normal colonic cells and CRC cell lines by flow cytometry combined with immunofluorescence, and verified the expression levels of seven lncRNAs using real-time quantitative polymerase chain reaction. Finally, combined drug sensitivity analysis using the Genomics of Drug Sensitivity in Cancer, Cancer Therapeutics Response Portal, and Profiling Relative Inhibition Simultaneously in Mixtures indicated that the sialylation-related lncRNA signature could serve as a potential predictor for chemosensitivity. Collectively, this is the first sialylation lncRNA-based signature for predicting the prognosis, immune landscape, and chemotherapeutic response in CRC, and may provide vital guidance to facilitate risk stratification and optimize individualized therapy for CRC patients.

The CDK1-Related lncRNA and CXCL8 Mediated Immune Resistance in Lung Adenocarcinoma

Background: Limited therapeutic options are available for advanced LUAD without driver gene mutations. Anti-CDK therapy has shown effectiveness in several kind of cancers, however, the mechanisms still need to be elucidated. Materials and Methods: The lncRNA associated with CDK1 and the immunomodulatory factors that regulate CDK1 were found by bioinformatics analysis and experimental verification. The prognostic model and immune resistance mechanism of lung adenocarcinoma were revealed by single cell analysis, immune infiltration analysis, and signal pathway analysis. Results: LINC00261 was found to be an important CDK1-related lncRNA with a better prognosis in LUAD. In addition, high CDK1 expression indicates a poor immunotherapy response, which may be associated with overexpression of CXCL8. CXCL8 decreased in patients who were immunotherapy-responsive but increased in patients who were immunotherapy-resistant. Signaling pathway analysis suggested that increased CXCL8 and decreased LINC00261 may participate in hypoxia-induced tumor angiogenesis and cause a poor prognosis for the patients. CXCL8 and CDK1 may change G2-M transformation and EMT and promote tumor proliferation. Conclusion: This study explained that LINC00261, CDK1, and CXCL8 may have a mutual regulation relationship, which affects the occurrence of LUAD and the efficacy of immunotherapy.

Long non‑coding RNAs interact with RNA‑binding proteins to regulate genomic instability in cancer cells (Review)

Genomic instability, a feature of most cancers, contributes to malignant cell transformation and cancer progression due to the accumulation of genetic alterations. Genomic instability is reflected at numerous levels, from single nucleotide to the chromosome levels. However, the exact molecular mechanisms and regulators of genomic instability in cancer remain unclear. Growing evidence indicates that the binding of long non-coding RNAs (lncRNAs) to protein chaperones confers a variety of regulatory functions, including managing of genomic instability. The aim of the present review was to examine the roles of mitosis, telomeres, DNA repair, and epigenetics in genomic instability, and the mechanisms by which lncRNAs regulate them by binding proteins in cancer cells. This review contributes to our understanding of the role of lncRNAs and genomic instability in cancer and can potentially provide entry points and molecular targets for cancer therapies.

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

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

LINC00261 Inhibits Esophageal Cancer Radioresistance by Down-Regulating microRNA-552-3p and Promoting DIRAS1

OBJECTIVE

Esophageal cancer (EC) represents a life-threatening tumor with an ever-increasing incidence rate. Long intergenic non-protein coding RNAs (LINCs) have also become a topic of interest in EC. In a similar light, the current study aimed to investigate the role of LINC00261 in EC radioresistance.

METHODS

Firstly, radioresistant EC cell lines TE-1-R and TE-5-R were established using TE-1 and TE-5 cells. Subsequently, LINC00261, microRNA (miR)-552-3p, and DIRAS1 expression patterns in EC tissues and adjacent normal tissues and EC cells were evaluated. In addition, survival fraction (SF), colony formation, apoptosis, and γ-H2AX levels were analyzed, followed by the detection of the binding relation between LINC00261 and miR-552-3p and between miR-552-3p and DIRAS1. Lastly, xenograft transplantation was carried out to confirm the effects of LINC00261 on EC radioresistance in vivo.

RESULTS

LINC00261 and DIRAS1 were poorly-expressed in EC tissues and cells, but miR-552-3p was over-expressed. In EC cells with X-ray radiation, over-expression of LINC00261 reduced SF and cell viability, strengthened γ-H2AX levels, and promoted apoptosis, while all these trends were counteracted by miR-522-3p over-expression or DIRAS1 silencing. Mechanistic investigation further validated the binding relation between LINC00261 and miR-552-3p, and between miR-552-3p and DIRAS1. Moreover, LINC00261 over-expression suppressed tumor growth and reduced EC radioresistance in vivo.

CONCLUSION

Altogether, our findings indicated that LINC00261 exerts a suppressive effect on EC radioresistance via the competing endogenous RNA network to sponge miR-552-3p and up-regulate DIRAS1 transcription.

Long Noncoding Competing Endogenous RNA Networks in Pancreatic Cancer

Pancreatic cancer (PC) is a highly malignant disease characterized by insidious onset, rapid progress, and poor therapeutic effects. The molecular mechanisms associated with PC initiation and progression are largely insufficient, hampering the exploitation of novel diagnostic biomarkers and development of efficient therapeutic strategies. Emerging evidence recently reveals that noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), extensively participate in PC pathogenesis. Specifically, lncRNAs can function as competing endogenous RNAs (ceRNAs), competitively sequestering miRNAs, therefore modulating the expression levels of their downstream target genes. Such complex lncRNA/miRNA/mRNA networks, namely, ceRNA networks, play crucial roles in the biological processes of PC by regulating cell growth and survival, epithelial-mesenchymal transition and metastasis, cancer stem cell maintenance, metabolism, autophagy, chemoresistance, and angiogenesis. In this review, the emerging knowledge on the lncRNA-associated ceRNA networks involved in PC initiation and progression will be summarized, and the potentials of the competitive crosstalk as diagnostic, prognostic, and therapeutic targets will be comprehensively discussed.

Isotretinoin and Thalidomide Down-Regulate c-MYC Gene Expression and Modify Proteins Associated with Cancer in Hepatic Cells

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. The number of cases is increasing and the trend for the next few years is not encouraging. HCC is usually detected in the advanced stages of the disease, and pharmacological therapies are not entirely effective. For this reason, it is necessary to search for new therapeutic options. The objective of this work was to evaluate the effect of the drugs isotretinoin and thalidomide on c-MYC expression and cancer-related proteins in an HCC cellular model. The expression of c-MYC was measured using RT-qPCR and western blot assays. In addition, luciferase activity assays were performed for the c-MYC promoters P1 and P2 using recombinant plasmids. Dose-response-time analyses were performed for isotretinoin or thalidomide in cells transfected with the c-MYC promoters. Finally, a proteome profile analysis of cells exposed to these two drugs was performed and the results were validated by western blot. We demonstrated that in HepG2 cells, isotretinoin and thalidomide reduced c-MYC mRNA expression levels, but this decrease in expression was linked to the regulation of P1 and P1-P2 c-MYC promoter activity in isotretinoin only. Thalidomide did not exert any effect on c-MYC promoters. Also, isotretinoin and thalidomide were capable of inducing and repressing proteins associated with cancer. In conclusion, isotretinoin and thalidomide down-regulate c-MYC mRNA expression and this is partially due to P1 or P2 promoter activity, suggesting that these drugs could be promising options for modulating the expression of oncogenes and tumor suppressor genes in HCC.

The Contribution of Autophagy and LncRNAs to MYC-Driven Gene Regulatory Networks in Cancers

MYC is a target of the Wnt signalling pathway and governs numerous cellular and developmental programmes hijacked in cancers. The amplification of MYC is a frequently occurring genetic alteration in cancer genomes, and this transcription factor is implicated in metabolic reprogramming, cell death, and angiogenesis in cancers. In this review, we analyse MYC gene networks in solid cancers. We investigate the interaction of MYC with long non-coding RNAs (lncRNAs). Furthermore, we investigate the role of MYC regulatory networks in inducing changes to cellular processes, including autophagy and mitophagy. Finally, we review the interaction and mutual regulation between MYC and lncRNAs, and autophagic processes and analyse these networks as unexplored areas of targeting and manipulation for therapeutic gain in MYC-driven malignancies.

LINC00261 Suppresses Cisplatin Resistance of Esophageal Squamous Cell Carcinoma Through miR-545-3p/MT1M Axis

To improve the survival rate and cure rate of patients, it is necessary to find a new treatment scheme according to the molecular composition of (ESCC) in esophageal squamous cell carcinoma. Long non-coding RNAs (lncRNAs) regulate the progression of ESCC by various pathophysiological pathways. We explored the possible function of the lncRNA LINC00261 (LINC00261) on cisplatin (DDP) resistance of ESCC and its relative molecular mechanisms. In the study, we found that LINC00261 was downregulated in ESCC tissues, cell lines, and DDP-resistant ESCC patients. Besides, overexpression of LINC00261 not only inhibited cell proliferation, and DDP resistance but also promotes cell apoptosis. Further mechanistic research showed that LINC00261 sponged miR-545-3p which was negatively correlated with the expression of LINC00261. In addition, functional experiments revealed that upregulation of miR-766-5p promoted proliferation and enhanced DDP resistance. Subsequently, MT1M was testified to be the downstream target gene of miR-545-3p. Rescue experiments revealed that overexpression of MT1M largely restores miR-545-3p mimics-mediated function on ESCC progression. Our results demonstrate that the LINC00261 suppressed the DDP resistance of ESCC through miR-545-3p/MT1M axis.

LncRNA CERS6-AS1 promotes proliferation and metastasis through the upregulation of YWHAG and activation of ERK signaling in pancreatic cancer

LncRNAs play essential regulatory roles in pancreatic cancer (PC) tumorigenesis and progression. We aimed to investigate the role of lncRNA CERS6-AS1 in PC. CERS6-AS1 expression was determined in PC tissues and cell lines by PCR analysis. The roles of CERS6-AS1 on proliferation, migration, invasion, and epithelial to mesenchymal transition (EMT) were confirmed via CCK-8 assay, EDU assay, transwell assay, wound healing assay, and western blot assay. Besides, the interaction between CERS6-AS1 and their target genes was verified by luciferase report assays and RIP assays. Animal assays and clinical data analysis were performed to validate the functions in vivo. We found that lncRNA CERS6-AS1 was highly expressed in PC tissues and cells. Additionally, high expression of CERS6-AS1 was obviously associated with poor prognosis. Functional assays demonstrated that CERS6-AS1 downregulation significantly inhibited PC cell growth and migration. Moreover, CERS6-AS1 exerted as a molecular sponge for miR-217-5p (miR-217), and miR-217 was confirmed as a potential target of CERS6-AS1. Subsequently, miR-217 suppressed PC cell proliferation and metastasis by directly targeting YWHAG, which interacted with RAF1 and promoted its phosphorylation, leading to RAF1-mediated ERK signaling activation and translocation of phosphorylated ERK from the cytoplasm to the nucleus. Mechanically, CERS6-AS1 silencing significantly inhibited PC cell proliferation and metastasis via a miR-217/YWHAG/RAF1 signaling axis. CERS6-AS1 exerts as a carcinogen in PC to promote malignant features and behaves as a competitive endogenous RNA for miR-217. We identified CERS6-AS1 as a potential biomarker or therapeutic target to improve PC diagnosis and treatment outcomes.

LINC00261: a burgeoning long noncoding RNA related to cancer

Long noncoding RNAs (lncRNAs), are transcripts longer than 200 nucleotides that are considered to be vital regulators of many cellular processes, particularly in tumorigenesis and cancer progression. long intergenic non-protein coding RNA 261 (LINC00261), a recently discovered lncRNA, is abnormally expressed in a variety of human malignancies, including pancreatic cancer, gastric cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, breast cancer, laryngeal carcinoma, endometrial carcinoma, esophageal cancer, prostate cancer, choriocarcinoma, and cholangiocarcinoma. LINC00261 mainly functions as a tumor suppressor that regulates a variety of biological processes in the above-mentioned cancers, such as cell proliferation, apoptosis, motility, chemoresistance, and tumorigenesis. In addition, the up-regulation of LINC00261 is closely correlated with both favorable prognoses and many clinical characteristics. In the present review, we summarize recent research documenting the expression and biological mechanisms of LINC00261 in tumor development. These findings suggest that LINC00261, as a tumor suppressor, has bright prospects both as a biomarker and a therapeutic target.

Regulation of Nrf2 signaling pathway in heart failure: Role of extracellular vesicles and non-coding RNAs

The balance between pro- and antioxidant molecules has been established as an important driving force in the pathogenesis of cardiovascular disease. Chronic heart failure is associated with oxidative stress in the myocardium and globally. Redox balance in the heart and brain is controlled, in part, by antioxidant proteins regulated by the transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2), which is reduced in the heart failure state. Nrf2 can, in turn, be regulated by a variety of mechanisms including circulating microRNAs (miRNAs) encapsulated in extracellular vesicles (EVs) derived from multiple cell types in the heart. Here, we review the role of the Nrf2 and antioxidant enzyme signaling pathway in mediating redox balance in the myocardium and the brain in the heart failure state. This review focuses on Nrf2 and antioxidant protein regulation in the heart and brain by miRNA-enriched EVs in the setting of heart failure. We discuss EV-mediated intra- and inter-organ communications especially, communication between the heart and brain via an EV pathway that mediates cardiac function and sympatho-excitation in heart failure. Importantly, we speculate how engineered EVs with specific miRNAs or antagomirs may be used in a therapeutic manner in heart failure.

Fucoidan Inhibits the Progression of Hepatocellular Carcinoma via Causing lncRNA LINC00261 Overexpression

Hepatocellular carcinoma (HCC) as a main type of primary liver cancers has become one of the most deadly tumors because of its high morbidity and poor prognosis. Fucoidan is a family of natural, heparin-like sulfated polysaccharides extracted from brown algae. It is not only a widely used dietary supplement, but also participates in many biological activities, such as anti-oxidation, anti-inflammation and anti-tumor. However, the mechanism of fucoidan induced inhibition of HCC is elusive. In our study, we demonstrated that fucoidan contributes to inhibiting cell proliferation in vivo and in vitro, restraining cell motility and invasion and inducing cell cycle arrest and apoptosis. According to High-Throughput sequencing of long-non-coding RNA (lncRNA) in MHCC-97H cells treated with 0.5 mg/mL fucoidan, we found that 56 and 49 lncRNAs were correspondingly up- and down-regulated. LINC00261, which was related to the progression of tumor, was highly expressed in fucoidan treated MHCC-97H cells. Moreover, knocking down LINC00261 promoted cell proliferation by promoting the expression level of miR-522-3p, which further decreased the expression level of downstream SFRP2. Taken together, our results verified that fucoidan effectively inhibits the progression of HCC via causing lncRNA LINC00261 overexpression.

A Signature of Nine lncRNA Methylated Genes Predicts Survival in Patients With Glioma

Glioma is one of the most common malignant tumors of the central nervous system, and its prognosis is extremely poor. Aberrant methylation of lncRNA promoter region is significantly associated with the prognosis of glioma patients. In this study, we investigated the potential impact of methylation of lncRNA promoter region in glioma patients to establish a signature of nine lncRNA methylated genes for determining glioma patient prognosis. Methylation data and clinical follow-up data were obtained from The Cancer Genome Atlas (TCGA). The multistep screening strategy identified nine lncRNA methylated genes that were significantly associated with the overall survival (OS) of glioma patients. Subsequently, we constructed a risk signature that containing nine lncRNA methylated genes. The risk signature successfully divided the glioma patients into high-risk and low-risk groups. Compared with the low-risk group, the high-risk group had a worse prognosis, higher glioma grade, and older age. Furthermore, we identified two lncRNAs termed PCBP1-AS1 and LINC02875 that may be involved in the malignant progression of glioma cells by using the TCGA database. Loss-of-function assays confirmed that knockdown of PCBP1-AS1 and LINC02875 inhibited the proliferation, migration, and invasion of glioma cells. Therefore, the nine lncRNA methylated genes signature may provide a novel predictor and therapeutic target for glioma patients.

Exosomal long non-coding RNAs in the diagnosis and oncogenesis of pancreatic cancer

Extracellular vesicles, specifically exosomes, play a significant role as an extracellular messenger through their transporting cargo. Of particular interest are the potential roles they play in pancreatic cancer, one of the leading causes of cancer-related mortality worldwide. Pancreatic Ductal Adenocarcinoma displays high chemo-resistance and metastatic ability, which may be influenced by cancer-derived exosomes carrying proteins, lipids and RNA. To date, among the most extensively examined exosomal molecular cargo there are long non-coding RNAs (lncRNAs) that, despite the increasing interest in their role and functions, are relatively poorly understood compared to other RNA transcripts. Nevertheless, we have witnessed an increasing interest for lncRNAs roles and functions in the past decade. For example, lncRNAs have been investigated as potential biomarkers for diagnosing pancreatic cancer and may have a role as therapeutics targets for precision medicine, but may also directly intervene in tumour progression features such as metastasis, epithelial to mesenchymal transition and resistance of cancer cells towards chemotherapy agents. The function of lncRNAs within various cancer exosomes is still undefined. In this review, we summarize the current knowledge on pancreatic cancer-derived exosome specific lncRNAs having prominent roles in genome integrity, pancreatic cancer progression and in other oncogenic hallmarks.

Epigenetic modifications of c-MYC: Role in cancer cell reprogramming, progression and chemoresistance

Both genetic and epigenetic mechanisms intimately regulate cancer development and chemoresistance. Different genetic alterations are observed in multiple genes, and most are irreversible. Aside from genetic alterations, epigenetic alterations play a crucial role in cancer. The reversible nature of epigenetic modifications makes them an attractive target for cancer prevention and therapy. Specific epigenetic alteration is also being investigated as a potential biomarker in multiple cancers. c-MYC is one of the most important transcription factors that are centrally implicated in multiple types of cancer cells reprogramming, proliferation, and chemoresistance. c-MYC shows not only genetic alterations but epigenetic changes in multiple cancers. It has been observed that epigenome aberrations can reversibly alter the expression of c-MYC, both transcriptional and translational levels. Understanding the underlying mechanism of the epigenetic alterations of c-MYC, that has its role in multiple levels of cancer pathogenesis, can give a better understanding of various unresolved questions regarding cancer. Recently, some researchers reported that targeting the epigenetic modifiers of c-MYC can successfully inhibit cancer cell proliferation, sensitize the chemoresistant cells, and increase the patient survival rate. As c-MYC is an important transcription factor, epigenetic therapy might be one of the best alternatives for the conventional therapies that assumes the "one-size-fits-all" role. It can also increase the precision of targeting and enhance the effectiveness of treatments among various cancer subtypes. In this review, we highlighted the role of epigenetically modified c-MYC in cancer cell reprogramming, progression, and chemoresistance. We also summarize the potential therapeutic approaches to target these modifications for the prevention of cancer development and chemoresistant phenotypes.