LncRNA MYCNOS facilitates proliferation and invasion in hepatocellular carcinoma by regulating miR-340

The multifaceted perspectives on the regulation of lncRNAs in hepatocellular carcinoma ferroptosis: from bench-to-bedside

Despite being characterized by high malignancy, high morbidity, and low survival rates, the underlying mechanism of hepatocellular carcinoma (HCC) has not been fully elucidated. Ferroptosis, a non-apoptotic form of regulated cell death, possesses distinct morphological, biochemical, and genetic characteristics compared to other types of cell death. Dysregulated actions within the molecular network that regulates ferroptosis have been identified as significant contributors to the progression of HCC. Long non-coding RNAs (lncRNAs) have emerged as influential contributors to diverse cellular processes, regulating gene function and expression through multiple mechanistic pathways. An increasing body of evidence indicates that deregulated lncRNAs are implicated in regulating malignant events such as cell proliferation, growth, invasion, and metabolism by influencing ferroptosis in HCC. Therefore, elucidating the inherent role of ferroptosis and the modulatory functions of lncRNAs on ferroptosis in HCC might promote the development of novel therapeutic interventions for this disease. This review provides a succinct overview of the roles of ferroptosis and ferroptosis-related lncRNAs in HCC progression and treatment, aiming to drive the development of promising therapeutic targets and biomarkers for HCC patients.

Identification of potential novel N6-methyladenosine effector-related lncRNA biomarkers for serous ovarian carcinoma: a machine learning-based exploration in the framework of 3P medicine

Background

Serous ovarian carcinoma (SOC) is considered the most lethal gynecological malignancy. The current lack of reliable prognostic biomarkers for SOC reduces the efficacy of predictive, preventive, and personalized medicine (PPPM/3PM) in patients with SOC, leading to unsatisfactory therapeutic outcomes. N6-methyladenosine (m6A) modification-associated long noncoding RNAs (lncRNAs) are effective predictors of SOC. In this study, an effective risk prediction model for SOC was constructed based on m6A modification-associated lncRNAs.

Methods

Transcriptomic data and clinical information of patients with SOC were downloaded from The Cancer Genome Atlas. Candidate lncRNAs were identified using univariate and multivariate and least absolute shrinkage and selection operator-penalized Cox regression analyses. The molecular mechanisms of m6A effector-related lncRNAs were explored via Gene Ontology, pathway analysis, gene set enrichment analysis, and gene set variation analysis (GSVA). The extent of immune cell infiltration was assessed using various algorithms, including CIBERSORT, Microenvironment Cell Populations counter, xCell, European Prospective Investigation into Cancer and Nutrition, and GSVA. The calcPhenotype algorithm was used to predict responses to the drugs commonly used in ovarian carcinoma therapy. In vitro experiments, such as migration and invasion Transwell assays, wound healing assays, and dot blot assays, were conducted to elucidate the functional roles of candidate lncRNAs.

Results

Six m6A effector-related lncRNAs that were markedly associated with prognosis were used to establish an m6A effector-related lncRNA risk model (m6A-LRM) for SOC. Immune microenvironment analysis suggested that the high-risk group exhibited a proinflammatory state and displayed increased sensitivity to immunotherapy. A nomogram was constructed with the m6A effector-related lncRNAs to assess the prognostic value of the model. Sixteen drugs potentially targeting m6A effector-related lncRNAs were identified. Furthermore, we developed an online web application for clinicians and researchers (https://leley.shinyapps.io/OC_m6A_lnc/). Overexpression of the lncRNA RP11-508M8.1 promoted SOC cell migration and invasion. METTL3 is an upstream regulator of RP11-508M8.1. The preliminary regulatory axis METTL3/m6A/RP11-508M8.1/hsa-miR-1270/ARSD underlying SOC was identified via a combination of in vitro and bioinformatic analyses.

Conclusion

In this study, we propose an innovative prognostic risk model and provide novel insights into the mechanism underlying the role of m6A-related lncRNAs in SOC. Incorporating the m6A-LRM into PPPM may help identify high-risk patients and personalize treatment as early as possible.

Long Non-Coding RNAs in Neuroblastoma: Pathogenesis, Biomarkers and Therapeutic Targets

Neuroblastoma is the most common malignant extracranial solid tumor of childhood. Recent studies involving the application of advanced high-throughput "omics" techniques have revealed numerous genomic alterations, including aberrant coding-gene transcript levels and dysfunctional pathways, that drive the onset, growth, progression, and treatment resistance of neuroblastoma. Research conducted in the past decade has shown that long non-coding RNAs, once thought to be transcriptomic noise, play key roles in cancer development. With the recent and continuing increase in the amount of evidence for the underlying roles of long non-coding RNAs in neuroblastoma, the potential clinical implications of these RNAs cannot be ignored. In this review, we discuss their biological mechanisms of action in the context of the central driving mechanisms of neuroblastoma, focusing on potential contributions to the diagnosis, prognosis, and treatment of this disease. We also aim to provide a clear, integrated picture of future research opportunities.

Epigenetic regulation of hepatocellular carcinoma progression: MicroRNAs as therapeutic, diagnostic and prognostic factors

Hepatocellular carcinoma (HCC), a significant challenge for public healthcare systems in developed Western countries including the USA, Canada, and the UK, is influenced by different risk factors including hepatitis virus infections, alcoholism, and smoking. The disruption in the balance of microRNAs (miRNAs) plays a vital function in tumorigenesis, given their function as regulators in numerous signaling networks. These miRNAs, which are mature and active in the cytoplasm, work by reducing the expression of target genes through their impact on mRNAs. MiRNAs are particularly significant in HCC as they regulate key aspects of the tumor, like proliferation and invasion. Additionally, during treatment phases such as chemotherapy and radiotherapy, the levels of miRNAs are key determinants. Pre-clinical experiments have demonstrated that altered miRNA expression contributes to HCC development, metastasis, drug resistance, and radio-resistance, highlighting related molecular pathways and processes like MMPs, EMT, apoptosis, and autophagy. Furthermore, the regulatory role of miRNAs in HCC extends beyond their immediate function, as they are also influenced by other epigenetic factors like lncRNAs and circular RNAs (circRNAs), as discussed in recent reviews. Applying these discoveries in predicting the prognosis of HCC could mark a significant advancement in the therapy of this disease.

Origin of functional de novo genes in humans from "hopeful monsters"

For a long time, it was believed that new genes arise only from modifications of preexisting genes, but the discovery of de novo protein-coding genes that originated from noncoding DNA regions demonstrates the existence of a "motherless" origination process for new genes. However, the features, distributions, expression profiles, and origin modes of these genes in humans seem to support the notion that their origin is not a purely "motherless" process; rather, these genes arise preferentially from genomic regions encoding preexisting precursors with gene-like features. In such a case, the gene loci are typically not brand new. In this short review, we will summarize the definition and features of human de novo genes and clarify their process of origination from ancestral non-coding genomic regions. In addition, we define the favored precursors, or "hopeful monsters," for the origin of de novo genes and present a discussion of the functional significance of these young genes in brain development and tumorigenesis in humans. This article is categorized under: RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution.

Evolution and implications of de novo genes in humans

Genes and translated open reading frames (ORFs) that emerged de novo from previously non-coding sequences provide species with opportunities for adaptation. When aberrantly activated, some human-specific de novo genes and ORFs have disease-promoting properties-for instance, driving tumour growth. Thousands of putative de novo coding sequences have been described in humans, but we still do not know what fraction of those ORFs has readily acquired a function. Here, we discuss the challenges and controversies surrounding the detection, mechanisms of origin, annotation, validation and characterization of de novo genes and ORFs. Through manual curation of literature and databases, we provide a thorough table with most de novo genes reported for humans to date. We re-evaluate each locus by tracing the enabling mutations and list proposed disease associations, protein characteristics and supporting evidence for translation and protein detection. This work will support future explorations of de novo genes and ORFs in humans.

The lncRNA KIF9-AS1 Accelerates Hepatocellular Carcinoma Growth by Recruiting DNMT1 to Promote RAI2 DNA Methylation

Background

Hepatocellular carcinoma (HCC) is a very common malignant tumor. Long noncoding RNAs (lncRNAs) enable discoveries of new therapeutic tumor targets. We aimed to study the role and potential regulatory mechanisms of the lncRNA KIF9-AS1 in HCC.

Methods

CCK-8, scratch assay, and flow cytometry were used to detect cell proliferation, migration, and apoptosis, respectively. Bax, Bcl-2, ERK, and pERK expression were measured by western blotting. StarBase predicted KIF9-AS1 expression in HCC and paracancerous tissues. RPISeq predicted the interaction score of KIF9-AS1 and DNMT1, and MethyPrimer revealed the CpG island distribution in the RAI2 promoter. MSP was performed to measure RAI2 methylation. RIP and ChIP were performed to examine lncRNA KIF9-AS1, DNMT1, and RAI2 interactions. Finally, the effect of KIF9-AS1 knockdown on HCC was verified with nude mice.

Results

We found that KIF9-AS1 expression was increased in HCC tissues. KIF9-AS1 knockdown inhibited the proliferation and migration, and facilitated the apoptosis of HCC cells. lncRNA KIF9-AS1-mediated RAI2 expression led to DNMT1 recruitment and regulated RAI2 DNA methylation. RAI2 overexpression inhibited the proliferation and migration and promoted the apoptosis of HCC cells. KIF9-AS1 knockdown inhibited subcutaneous tumor formation in vivo.

Conclusion

This study shows that KIF9-AS1 accelerates HCC growth by inducing DNMT1 promotion of RAI2 DNA methylation.

C10orf55, CASC2, and SFTA1P lncRNAs Are Potential Biomarkers to Assess Radiation Therapy Response in Head and Neck Cancers

Long non-coding RNAs have proven to be important molecules in carcinogenesis. Due to little knowledge about them, the molecular mechanisms of tumorigenesis are still being explored. The aim of this work was to study the effect of ionizing radiation on the expression of lncRNAs in head and neck squamous cell carcinoma (HNSCC) in patients responding and non-responding to radiotherapy. The experimental model was created using a group of patients with response (RG, n = 75) and no response (NRG, n = 75) to radiotherapy based on the cancer genome atlas (TCGA) data. Using the in silico model, statistically significant lncRNAs were defined and further validated on six HNSCC cell lines irradiated at three different doses. Based on the TCGA model, C10orf55, C3orf35, C5orf38, CASC2, MEG3, MYCNOS, SFTA1P, SNHG3, and TMEM105, with the altered expression between the RG and NRG were observed. Analysis of pathways and immune profile indicated that these lncRNAs were associated with changes in processes, such as epithelial-to-mesenchymal transition, regulation of spindle division, and the p53 pathway, and differences in immune cells score and lymphocyte infiltration signature score. However, only C10orf55, CASC2, and SFTA1P presented statistically altered expression after irradiation in the in vitro model. In conclusion, the expression of lncRNAs is affected by ionization radiation in HNSCC, and these lncRNAs are associated with pathways, which are important for radiation response and immune response. Potentially presented lncRNAs could be used as biomarkers for personalized radiotherapy in the future. However, these results need to be verified based on an in vitro experimental model to show a direct net of interactions.

LncRNA-FAM66C Was Identified as a Key Regulator for Modulating Tumor Microenvironment and Hypoxia-Related Pathways in Glioblastoma

Although the role of hypoxia has been greatly explored and unveiled in glioblastoma (GBM), the mechanism of hypoxia-related long non-coding (lnc) RNAs has not been clearly understood. This study aims to reveal the crosstalk among hypoxia-related lncRNAs, tumor microenvironment (TME), and tumorigenesis for GBM. Gene expression profiles of GBM patients were used as a basis for identifying hypoxia-related lncRNAs. Unsupervised consensus clustering was conducted for classifying samples into different molecular subtypes. Gene set enrichment analysis (GSEA) was performed to analyze the enrichment of a series of genes or gene signatures. Three molecular subtypes were constructed based on eight identified hypoxia-related lncRNAs. Oncogenic pathways, such as epithelial mesenchymal transition (EMT), tumor necrosis factor-α (TNF-α) signaling, angiogenesis, hypoxia, P53 signaling, and glycolysis pathways, were significantly enriched in C1 subtype with poor overall survival. C1 subtype showed high immune infiltration and high expression of immune checkpoints. Furthermore, we identified 10 transcription factors (TFs) that were highly correlated with lncRNA-FAM66C. Three key lncRNAs (ADAMTS9-AS2, LINC00968, and LUCAT1) were screened as prognostic biomarkers for GBM. This study shed light on the important role of hypoxia-related lncRNAs for TME modulation and tumorigenesis in GBM. The eight identified hypoxia-related lncRNAs, especially FAM66C may serve as key regulators involving in hypoxia-related pathways.

Remifentanil reduces the proliferation, migration and invasion of HCC cells via lncRNA NBR2/miR‐650/TIMP3 axis

Cancer cell hyperproliferation and metastasis are major causes of cancer-associated mortality. Although the use of anaesthetics and analgesics may affect cancer cell metastasis, the underlying molecular mechanism remains unclear. This study aimed to explore the mechanisms of action of remifentanil on hepatocellular carcinoma (HCC) progression. Cell viability was measured by the 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-h-tetrazolium bromide assay. Quantitative real-time polymerase chain reaction and Western blotting were performed to assess the expression levels of long non-coding RNA (lncRNA) neighbour of BRCA1 gene 2 (NBR2), microRNA (miR)-650 and tissue inhibitor of metalloproteinase-3 (TIMP3) in HCC cells. Wound healing and transwell assays were employed to evaluate the migration and invasion of HCC cells respectively. The target relationships between miR-650 and NBR2/TIMP3 were confirmed by dual luciferase reporter assay. Remifentanil reduced the viability of HCC cells in a dose-dependent manner. Remifentanil treatment significantly increased the expression of lncRNA NBR2 and TIMP3, and repressed miR-650 expression in HCC cells. Decreased lncRNA NBR2 or increased miR-650 promoted the proliferation, migration and invasion of remifentanil-treated HCC cells. LncRNA NBR2 targeted miR-650, and miR-650 further targeted TIMP3. Moreover, miR-650 down-regulation or TIMP3 up-regulation reversed the effects of lncRNA NBR2 knockdown that caused an enhancement of cell viability, migration and invasiveness in remifentanil-treated HCC cells. Thus remifentanil reduces the proliferation, migration and invasion of HCC cells via the lncRNA NBR2/miR-650/TIMP3 axis in vitro.

Comprehensive analysis of epigenetic modifications and immune-cell infiltration in tissues from patients with systemic lupus erythematosus

Aim: To explore potential abnormal epigenetic modifications and immune-cell infiltration in tissues from systemic lupus erythematosus (SLE) patients. Materials & methods: To utilize bioinformatics analysis and 'wet lab' methods to identify and verify differentially expressed genes in multiple targeted organs in SLE. Results: Seven key genes, IFI44, IFI44L, IFIT1, IFIT3, PLSCR1, RSAD2 and OAS2, which are regulated by epigenetics and may be involved in the pathogenesis of SLE, are identified by combined long noncoding RNA-miRNA-mRNA network analysis and DNA methylation analysis. The results of quantitative reverse transcription PCR, immunohistochemistry and DNA methylation analysis confirmed the potential of these genes as biomarkers. Conclusion: This study reveals the potential mechanisms in SLE from epigenetic modifications and immune-cell infiltration, providing diagnostic biomarkers and therapeutic targets for SLE.

LncRNA GASAL1 promotes hepatocellular carcinoma progression by up-regulating USP10-stabilized PCNA

Hepatocellular carcinoma (HCC) is a fatal malignancy which has insufficient treatment options. Long non-coding RNA (lncRNA) GASAL1 was discovered to be conspicuously up-regulated in HCC. However, the study on the role of GASAL1 in HCC reamins limited. Our study aimed at exploring the role and mechanism of GASAL1 in HCC. RT-qPCR or Western blot was conducted to examine the expression of RNAs or proteins. Functional assays were carried out to investigate the impact of GASAL1, USP10, and PCNA on HCC cells. Mechanism assays were performed to fathom out the relationship among GASAL1, miR-193b-5p, USP10, and PCNA. In vivo assays were also employed to determine the role of GASAL1 in HCC tumor growth and metastases. According to the data collected, GASAL1 displayed a high expression in HCC cells and GASAL1 knockdown led to impeded cell proliferation and migration, as well as tumor progression. A series of mechanism analysis demonstrated GASAL1 could sponge miR-193b-5p to raise the expression of USP10. Moreover, USP10 could induce PCNA deubiquitination to promote HCC cell growth. To conclude, GASAL1 plays an oncogenic role in HCC. GASAL1 could up-regulate USP10 via competitively binding to miR-193b-5p. And USP10 could strengthen cell proliferative and migratory abilities through deubiquitinating PCNA.

miR-152-mediated MKK7 downregulation is attenuated by MYCNOS in ovarian adenocarcinoma

MYCN opposite strand (MYCNOS) acts as an oncogenic long non-coding RNA in liver cancer. However, its role in other cancer types is unknown. The aim of the present study was to investigate the function of MYCNOS in ovarian adenocarcinoma (OA). MYCNOS expression in OA was determined using reverse transcription-quantitative PCR (RT-qPCR), and its prognostic value for OA was evaluated in a 5-year follow-up study. The predicted interaction between MYCNOS and microRNA (miR)-152 was confirmed using a dual luciferase reporter assay. The association between MYCNOS and miR-152 was also analyzed in overexpression experiments. The effects of MYCNOS and miR-152 on mitogen-activated protein kinase kinase 7 (MKK7) expression were explored using RT-qPCR and western blotting. Cell proliferation was analyzed using a Cell Counting Kit-8 assay. MYCNOS expression was found to be upregulated in OA and predicted poor survival. In addition, MYCNOS was predicted to interact with miR-152, and a dual luciferase assay confirmed this interaction. However, MYCNOS and miR-152 overexpression did not affect their mutual expression levels. MYCNOS overexpression upregulated MKK7, a target of miR-152. Cell proliferation increased following simultaneous MYCNOS and MKK7 overexpression, but was reduced following miR-152 overexpression. Moreover, MYCNOS overexpression attenuated the effects of miR-152 overexpression. In conclusion, MYCNOS may act by sponging miR-152 to upregulate MKK7 expression in OA, thereby promoting cell proliferation.

Long non-coding RNA TMCC1-AS1 predicts poor prognosis and accelerates epithelial-mesenchymal transition in liver cancer

Long non-coding RNA transmembrane and coiled-coil domain family 1 antisense RNA 1 (TMCC1-AS1) has been frequently reported to be associated with prognosis in patients with liver cancer (LC). However, the biological role of TMCC1-AS1 in LC in vitro remains unclear. The expression levels of TMCC1-AS1 in primary tumor tissues and LC cell lines were determined using reverse transcription-quantitative PCR. The associations between TMCC1-AS1 expression and the clinicopathological factors of patients with LC were statistically analyzed using the χ² test. The role of TMCC1-AS1 in LC prognosis was assessed using Kaplan-Meier curves and proportional hazards model (Cox) analysis. Cell proliferation was determined by Cell Counting Kit-8 and colony formation assays. Transwell assays were performed to determine migration and invasion. TMCC1-AS1 expression was found to be significantly upregulated in LC tissues and cell lines compared with the corresponding controls. High TMCC1-AS1 expression was associated with advanced TNM stage and lymph node metastasis. Furthermore, high TMCC1-AS1 expression predicted poor survival in patients with LC. Knockdown of TMCC1-AS1 significantly inhibited the proliferation, migration and invasion of HepG2 and SNU-182 cells, while overexpression of TMCC1-AS1 had the opposite effect in HepG2 and SNU-182 cells. At the molecular level, downregulation of TMCC1-AS1 expression resulted in increased E-cadherin expression and decreased proliferating cell nuclear antigen, Ki67, N-cadherin and Vimentin expression in HepG2 cells. Overexpression of TMCC1-AS1 had the opposite effects on these factors in SNU-182 cells. In conclusion, the present findings indicated that TMCC1-AS1 might be considered as a novel oncogene, which promotes cell proliferation and migration, and may be a potential therapeutic target for LC.

Secondary Structure of Human De Novo Evolved Gene Product NCYM Analyzed by Vacuum-Ultraviolet Circular Dichroism

NCYM, a cis-antisense gene of MYCN, encodes a Homininae-specific protein that promotes the aggressiveness of human tumors. Newly evolved genes from non-genic regions are known as de novo genes, and NCYM was the first de novo gene whose oncogenic functions were validated in vivo. Targeting NCYM using drugs is a potential strategy for cancer therapy; however, the NCYM structure must be determined before drug design. In this study, we employed vacuum-ultraviolet circular dichroism to evaluate the secondary structure of NCYM. The SUMO-tagged NCYM and the isolated SUMO tag in both hydrogenated and perdeuterated forms were synthesized and purified in a cell-free in vitro system, and vacuum-ultraviolet circular dichroism spectra were measured. Significant differences between the tagged NCYM and the isolated tag were evident in the wavelength range of 190–240 nm. The circular dichroism spectral data combined with a neural network system enabled to predict the secondary structure of NCYM at the amino acid level. The 129-residue tag consists of α-helices (approximately 14%) and β-strands (approximately 29%), which corresponded to the values calculated from the atomic structure of the tag. The 238-residue tagged NCYM contained approximately 17% α-helices and 27% β-strands. The location of the secondary structure predicted using the neural network revealed that these secondary structures were enriched in the Homininae-specific region of NCYM. Deuteration of NCYM altered the secondary structure at D90 from an α-helix to another structure other than α-helix and β-strand although this change was within the experimental error range. All four nonsynonymous single-nucleotide polymorphisms (SNPs) in human populations were in this region, and the amino acid alteration in SNP N52S enhanced Myc-nick production. The D90N mutation in NCYM promoted NCYM-mediated MYCN stabilization. Our results reveal the secondary structure of NCYM and demonstrated that the Homininae-specific domain of NCYM is responsible for MYCN stabilization.

LncRNA MYCNOS promotes glioblastoma cell proliferation by regulating miR-216b/FOXM1 axis

MYCNOS is an oncogenic lncRNA in liver cancer, but its role in glioblastoma (GBM) is unknown. We predicted that MYCNOS might interact with miR-216b, which targets FOXM1 to perform tumor suppressive roles. This study was performed to analyze the role of MYCNOS in GBM and explore its potential interactions with miR-216b and FOXM1. MYCNOS expression in paired GBM and non-tumor tissues from 62 GBM patients was analyzed by RT-qPCR. The interaction between MYCNOS and miR-216b was predicted by IntaRNA 2.0 and confirmed by dual luciferase activity assay. Overexpression of MYCNOS, miR-216b, and FOXM1 was achieved in GBM cells, followed by performing RT-qPCR and Western blot to explore the relationship among them. CCK-8 assay was performed to explore the role of MYCNOS, miR-216b, and FOXM1 in regulating GBM cell proliferation. MYCNOS was upregulated in GBM tissues compared to the paired non-tumor tissues. MYCNOS is predicted to interact with miR-216b, but overexpression of MYCNOS and miR-216b failed to affect each other's expression significantly. Dual luciferase activity assay showed that MYCNOS and miR-216b could directly interact with each other. MYCNOS overexpression increased the expression of FOXM1, which is a direct target of miR-216b. Cell proliferation assay showed that MYCNOS and FOXM1 overexpression resulted in an increased proliferation rate of GBM cells, while miR-216b overexpression suppressed cell proliferation. Moreover, MYCNOS overexpression suppressed the role of miR-216b. MYCNOS may regulate FOXM1 expression of by serving as an endogenous sponge of miR-216b axis to promote the proliferation of GBM cells.

Silencing of the Long Noncoding RNA MYCNOS1 Suppresses Activity of MYCN-Amplified Retinoblastoma Without RB1 Mutation

Purpose

MYCNOS (MYCN opposite strand) is co-amplified with MYCN in pediatric cancers, including retinoblastoma. MYCNOS encodes several RNA variants whose functions have not been elucidated in retinoblastoma. Thus, we attempted to identify MYCNOS variants in retinoblastoma and aimed to decipher the role of MYCNOS variant 1 (MYCNOS1) on the activity of MYCN-amplified retinoblastoma.

Methods

The profiles of MYCNOS variants and MYCN status were determined in 17 retinoblastoma tissues, cell lines, retinas, and retinal organoids. A functional study of MYCNOS1 expression was conducted in patient-derived tumor cells and in retinoblastoma cell lines via short hairpin RNA-mediated gene silencing. We carried out MYCN expression, cell viability, cell cycle, apoptosis, soft agar colony formation, and transwell assays to examine the role of MYCNOS1 in MYCN and cell behaviors. We analyzed a transcriptome of MYCN-amplified retinoblastoma cells deficient for MYCNOS1 and, finally, tested the responses of these cells to chemotherapeutic agents.

Results

Expression of MYCNOS1 was associated with the expression and copy number of MYCN. Knockdown of MYCNOS1 caused instability of the MYCN protein, leading to cell cycle arrest and impaired proliferation and chemotaxis-directed migration in MYCN-amplified retinoblastoma cells in which RB1 was intact. MYCNOS1 expression was associated with gene signatures of photoreceptor cells and epithelial–mesenchymal transition. MYCNOS1 silencing enhanced the response of retinoblastoma cells to topotecan but not carboplatin.

Conclusions

MYCNOS1 supports progression of retinoblastoma. Inhibition of MYCNOS1 expression may be necessary to suppress MYCN activity when treating MYCN-amplified cancers without RB1 mutation.

The Impact of Long Non-Coding RNAs in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the utmost deadly human malignancies. This type of cancer has been associated with several environmental, viral, and lifestyle risk factors. Among the epigenetic factors which contribute in the pathogenesis of HCC is dysregulation of long non-coding RNAs (lncRNAs). These transcripts modulate expression of several tumor suppressor genes and oncogenes and alter the activity of cancer-related signaling axes. Several lncRNAs such as NEAT1, MALAT1, ANRIL, and SNHG1 have been up-regulated in HCC samples. On the other hand, a number of so-called tumor suppressor lncRNAs namely CASS2 and MEG3 are down-regulated in HCC. The interaction between lncRNAs and miRNAs regulate expression of a number of mRNA coding genes which are involved in the pathogenesis of HCC. H19/miR-15b/CDC42, H19/miR-326/TWIST1, NEAT1/miR-485/STAT3, MALAT1/miR-124-3p/Slug, MALAT1/miR-195/EGFR, MALAT1/miR-22/SNAI1, and ANRIL/miR-144/PBX3 axes are among functional axes in the pathobiology of HCC. Some genetic polymorphisms within non-coding regions of the genome have been associated with risk of HCC in certain populations. In the current paper, we describe the recent finding about the impact of lncRNAs in HCC.

De novo evolved gene product NCYM in the pathogenesis and clinical outcome of human neuroblastomas and other cancers

NCYM is an antisense transcript of MYCN oncogene and promotes tumor progression. NCYM encodes a de novo protein whose open reading frame evolved from noncoding genomic regions in the ancestor of Homininae. Because of its topology, NCYM is always co-amplified with MYCN oncogene, and the mutual regulations between NCYM and MYCN maintain their expressions at high levels in MYCN-amplified tumors. NCYM stabilizes MYCN by inhibiting GSK3β, whereas MYCN stimulates transcription of both NCYM and MYCN. NCYM mRNA and its noncoding transcript variants MYCNOS have been shown to stimulate MYCN expression via direct binding to MYCN promoter, indicating that both coding and noncoding transcripts of NCYM induce MYCN expression. In contrast to the noncoding functions of NCYM, NCYM protein also promotes calpain-mediated cleavage of c-MYC. The cleaved product called Myc-nick inhibits cell death and promotes cancer cell migration. Furthermore, NCYM-mediated inhibition of GSK3β results in the stabilization of β-catenin, which promotes aggressiveness of bladder cancers. These MYCN-independent functions of NCYM showed their clinical significance in MYCN-non-amplified tumors, including adult tumors. This year is the 30th anniversary of the identification of NCYM/MYCNOS gene. On this special occasion, we summarize the current understanding of molecular functions and the clinical significance of NCYM and discuss future directions to achieve therapeutic strategies targeting NCYM.