title: HOXD-AS1 is a novel lncRNA encoded in HOXD cluster and a marker of neuroblastoma progression revealed via integrative analysis of noncoding transcriptome.
abstract: BACKGROUND
  Long noncoding RNAs (lncRNAs) constitute a major, but poorly characterized part of human transcriptome. Recent evidence indicates that many lncRNAs are involved in cancer and can be used as predictive and prognostic biomarkers. Significant fraction of lncRNAs is represented on widely used microarray platforms, however they have usually been ignored in cancer studies.
  
  
  RESULTS
  We developed a computational pipeline to annotate lncRNAs on popular Affymetrix U133 microarrays, creating a resource allowing measurement of expression of 1581 lncRNAs. This resource can be utilized to interrogate existing microarray datasets for various lncRNA studies. We found that these lncRNAs fall into three distinct classes according to their statistical distribution by length. Remarkably, these three classes of lncRNAs were co-localized with protein coding genes exhibiting distinct gene ontology groups. This annotation was applied to microarray analysis which identified a 159 lncRNA signature that discriminates between localized and metastatic stages of neuroblastoma. Analysis of an independent patient cohort revealed that this signature differentiates also relapsing from non-relapsing primary tumors. This is the first example of the signature developed via the analysis of expression of lncRNAs solely. One of these lncRNAs, termed HOXD-AS1, is encoded in HOXD cluster. HOXD-AS1 is evolutionary conserved among hominids and has all bona fide features of a gene. Studying retinoid acid (RA) response of SH-SY5Y cell line, a model of human metastatic neuroblastoma, we found that HOXD-AS1 is a subject to morphogenic regulation, is activated by PI3K/Akt pathway and itself is involved in control of RA-induced cell differentiation. Knock-down experiments revealed that HOXD-AS1 controls expression levels of clinically significant protein-coding genes involved in angiogenesis and inflammation, the hallmarks of metastatic cancer.
  
  
  CONCLUSIONS
  Our findings greatly extend the number of noncoding RNAs functionally implicated in tumor development and patient treatment and highlight their role as potential prognostic biomarkers of neuroblastomas.
authors.forename: Aliaksandr A
authors.initials: AA
authors.lastname: Yarmishyn
authors.forename: Arsen O
authors.initials: AO
authors.lastname: Batagov
authors.forename: Jovina Z
authors.initials: JZ
authors.lastname: Tan
authors.forename: Gopinath M
authors.initials: GM
authors.lastname: Sundaram
authors.forename: Prabha
authors.initials: P
authors.lastname: Sampath
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Kuznetsov
authors.forename: Igor V
authors.initials: IV
authors.lastname: Kurochkin
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D045744:Cell Line, Tumor; D018450:Disease Progression; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D056426:Genetic Loci / Q000235:genetics; D006801:Humans; D058977:Molecular Sequence Annotation; D005810:Multigene Family / Q000235:genetics*; D009447:Neuroblastoma / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011379:Prognosis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D062085:RNA, Long Noncoding / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D014157:Transcription Factors; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt