LncRNAs join hands together to regulate neuroblastoma progression.
ABSTRACT: Trait associated single nucleotide polymorphisms often overlap with noncoding transcripts but their contribution to disease phenotype is poorly investigated. Our study on neuroblastoma risk associated 6p22.3 locus derived long noncoding RNAs (lncRNAs) demonstrates that functional co-operation between sense-antisense CASC15 and NBAT1 lncRNAs control neuroblastoma progression via regulating SOX9-CHD7-USP36 regulatory axis.
Project description:Chromosome 6p22 was identified recently as a neuroblastoma susceptibility locus, but its mechanistic contributions to tumorigenesis are as yet undefined. Here we report that the most highly significant single-nucleotide polymorphism (SNP) associations reside within CASC15, a long noncoding RNA that we define as a tumor suppressor at 6p22. Low-level expression of a short CASC15 isoform (CASC15-S) associated highly with advanced neuroblastoma and poor patient survival. In human neuroblastoma cells, attenuating CASC15-S increased cellular growth and migratory capacity. Gene expression analysis revealed downregulation of neuroblastoma-specific markers in cells with attenuated CASC15-S, with concomitant increases in cell adhesion and extracellular matrix transcripts. Altogether, our results point to CASC15-S as a mediator of neural growth and differentiation, which impacts neuroblastoma initiation and progression.
Project description:In recent years, considerable advances have been made in the characterization of protein-coding alterations involved in the pathogenesis of melanoma. However, despite their growing implication in cancer, little is known about the role of long noncoding RNAs in melanoma progression. We hypothesized that copy number alterations (CNAs) of intergenic nonprotein-coding domains could help identify long intergenic noncoding RNAs (lincRNAs) associated with metastatic cutaneous melanoma. Among several candidates, our approach uncovered the chromosome 6p22.3 CASC15 (cancer susceptibility candidate 15) lincRNA locus as a frequently gained genomic segment in metastatic melanoma tumors and cell lines. The locus was actively transcribed in metastatic melanoma cells, and upregulation of CASC15 expression was associated with metastatic progression to brain metastasis in a mouse xenograft model. In clinical specimens, CASC15 levels increased during melanoma progression and were independent predictors of disease recurrence in a cohort of 141 patients with AJCC (American Joint Committee on Cancer) stage III lymph node metastasis. Moreover, small interfering RNA (siRNA) knockdown experiments revealed that CASC15 regulates melanoma cell phenotype switching between proliferative and invasive states. Accordingly, CASC15 levels correlated with known gene signatures corresponding to melanoma proliferative and invasive phenotypes. These findings support a key role for CASC15 in metastatic melanoma.
Project description:Long non-coding RNA (lncRNA) is responsible for a diverse range of cellular functions, such as transcriptional and translational regulation and variance in gene expression. The lncRNA CASC15 (cancer susceptibility candidate 15) is a long intergenic non-coding RNA (lincRNA) locus in chromosome 6p22.3. Previous research shows that lncRNA CASC15 is implicated in the biological behaviors of several cancers such as neuroblastoma and melanoma. Here, we aimed to explore in detail how CASC15 contributes to the growth of gastric cancer (GC). As predicted, the expression of CASC15 was enriched in GC tissues and cell lines as compared with healthy tissues and cells using qRT-PCR. The Kaplan-Meier method was used to demonstrate that high expression of CASC15 is linked to a poor prognosis for patients suffering from GC. Additionally, functional experiments proved that the down- or up-regulation of CASC15 inhibited or facilitated cell proliferation via the induction of cell cycle arrest and apoptosis, and also suppressed or accelerated cell migration and invasion by affecting the progression of the epithelial-to-mesenchymal transition (EMT). In vivo experiments showed that the knockdown of CASC15 lessened the tumor volume and weight and influenced the EMT process. This was confirmed by western blot assays and immunohistochemistry, indicating impaired metastatic ability in nude mice. CASC15 involvement in the tumorigenesis of GC occurs when CASC15 interacts with EZH2 and WDR5 to modulate CDKN1A in nucleus. Additionally, the knockdown of CASC15 triggered the silencing of ZEB1 in cytoplasm, which was shown to be associated with the competitive binding of CASC15 to miR-33a-5p.
Project description:Long non-coding RNAs (lncRNAs) have emerged as an important regulatory control in biological systems. Though the field of lncRNA has been progressing rapidly, a complete understanding of the role of lncRNAs in neuroblastoma pathogenesis is still lacking. To identify the abrogated lncRNAs in primary neuroblastoma and in the metastasized as well as the relapsed form of neuroblastoma, we analyzed an RNA-seq dataset on neuroblastoma that is available online to identify the lncRNAs that could potentially be contributing to the biology of neuroblastoma. The identified lncRNAs were further scrutinized using a publicly available epigenetic dataset of neuroblastoma and a cancer database. After this cross-sectional study, we were able to identify three significant lncRNAs, CASC15, PPP1R26-AS1, and USP3-AS1, which could serve as potential biomarkers in clinical studies of neuroblastoma pathogenesis.
Project description:We report 6p22 locus lncRNAs, which were identified as differentially expressed between high and non-high risk neuroblastoma tumors using RNA sequencing. we identified CASC15-003 and CASC15-004 lncRNAs act as prognostic biomarker in neuroblastoma. Overall design: Functional characterization for CASC15-003 and CASC15-004 lncRNAs was done using knockdown strategies followed by RNA-seq
Project description:BACKGROUND:Long non-coding RNAs (lncRNAs) play a variety of cellular roles, including regulation of transcription and translation, leading to alterations in gene expression. Some lncRNAs modulate the expression of chromosomally adjacent genes. Here, we assess the roles of the lncRNA CASC15 in regulation of a chromosomally nearby gene, SOX4, and its function in RUNX1/AML translocated leukemia. RESULTS:CASC15 is a conserved lncRNA that was upregulated in pediatric B-acute lymphoblastic leukemia (B-ALL) with t (12; 21) as well as pediatric acute myeloid leukemia (AML) with t (8; 21), both of which are associated with relatively better prognosis. Enforced expression of CASC15 led to a myeloid bias in development, and overall, decreased engraftment and colony formation. At the cellular level, CASC15 regulated cellular survival, proliferation, and the expression of its chromosomally adjacent gene, SOX4. Differentially regulated genes following CASC15 knockdown were enriched for predicted transcriptional targets of the Yin and Yang-1 (YY1) transcription factor. Interestingly, we found that CASC15 enhances YY1-mediated regulation of the SOX4 promoter. CONCLUSIONS:Our findings represent the first characterization of this CASC15 in RUNX1-translocated leukemia, and point towards a mechanistic basis for its action.
Project description:<h4>Background</h4>Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) are involved in the hypoxia-related cancer process and play pivotal roles in enabling malignant cells to survive under hypoxic stress. However, the molecular crosstalk between lncRNAs and hypoxia signaling cascades in non-small cell lung cancer (NSCLC) remains largely elusive.<h4>Methods</h4>Firstly, we identified differentially expressed lncRNA cancer susceptibility candidate 15 (CASC15) as associated with NSCLC based on bioinformatic data. The clinical significance of CASC15 in lung cancer was investigated by Kaplan-Meier survival analysis. Then, we modulated CASC15 expression in NSCLC cell lines by RNAi. CCK-8 and transwell assays were carried out to examine the effects of CASC15 on proliferation and migration of NSCLC cells. Upstream activator and downstream targets of CASC15 were validated by luciferase reporter assay, qRT-PCR, Western blotting, and chromatin immunoprecipitation (ChIP). Lastly, RNA in situ hybridization (RNA-ISH) and immunohistochemistry (IHC) were performed to confirm the genetic relationships between CASC15 and related genes in clinical samples.<h4>Results</h4>CASC15 was highly expressed in NSCLC tissues and closely associated with poor prognosis. Loss-of-function analysis demonstrated that CASC15 was essential for NSCLC cell migration and growth. Mechanistic study revealed that CASC15 was transcriptionally activated by hypoxia signaling in NSCLC cells. Further analysis showed that hypoxia-induced CASC15 transactivation was mainly dependent on hypoxia-inducible factor 1? (HIF-1?) and hypoxia response elements (HREs) located in CASC15 promoter. CASC15 promotes the expression of its chromosomally nearby gene, SOX4. Then SOX4 functions to stabilize ?-catenin protein, thereby enhancing the proliferation and migration of NSCLC cells. HIF-1?/CASC15/SOX4/?-catenin pathway was activated in a substantial subset of NSCLC patients.<h4>Conclusions</h4>HIF-1?/CASC15/SOX4/?-catenin axis plays an essential role in the development and progression of NSCLC. The present work provides new evidence that lncRNA CASC15 holds great promise to be used as novel biomarkers for NSCLC. Blocking the HIF-1?/CASC15/SOX4/?-catenin axis can serve as a potential therapeutic strategy for treating NSCLC.
Project description:Neuroblastoma is a disease that affects infants and despite intense multimodal therapy, high-risk patients have low survival rates (<50%). In recent years long noncoding RNAs (lncRNAs) have become the cutting edge of cancer research with inroads made in understanding their roles in multiple cancer types, including prostate and breast cancers. The roles of lncRNAs in neuroblastoma have just begun to be elucidated. This review summarises where we are with regards to lncRNAs in neuroblastoma. The known mechanistic roles of lncRNAs during neuroblastoma pathogenesis are discussed, as well as the relationship between lncRNA expression and the differentiation capacity of neuroblastoma cells. We speculate about the use of some of these lncRNAs, such as those mapping to the 6p22 hotspot, as biomarkers for neuroblastoma prognosis and treatment. This novel way of thinking about both neuroblastoma and lncRNAs brings a new perspective to the prognosis and treatment of high-risk patients.
Project description:In this case-control study, we analyzed the association between three single nucleotide polymorphisms (SNPs) in the CASC15 gene (rs6939340 A>G, rs4712653 T>C, and rs9295536 C>A) and neuroblastoma susceptibility in the Guangdong and Henan populations of China. We genotyped and analyzed 118 cases and 281 control subjects from Henan province and combined them with previously published data from the Guangdong population. In the Henan population, only the rs6939340 G>A variant homozygote AA was associated with decreased neuroblastoma risk [AA vs. GG: adjusted odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.23-0.98; P=0.045]. All three polymorphisms, individually and in combination, were associated with decreased neuroblastoma susceptibility in the Guangdong population. Moreover, subjects carrying 1-3 of these protective genotypes had lower neuroblastoma susceptibility than non-carriers (adjusted OR=0.65, 95% CI=0.51-0.84, P=0.0007). These results show that all three genetic variants of CASC15 identified in a genome-wide association study (GWAS) decrease neuroblastoma risk in two distinct Chinese populations.