LncRNA OIP5-AS1 is overexpressed in undifferentiated oral tumors and integrated analysis identifies as a downstream effector of stemness-associated transcription factors

Sci Rep. 2018 May 4;8(1):7018. doi: 10.1038/s41598-018-25451-3.

Abstract

Long non-coding RNAs (lncRNAs) play an important role in the regulation of key cellular processes in early development and cancer. LncRNA Oip5-as1 facilitates stem cell self-renewal in mouse by sponging mmu-miR-7 and modulating NANOG level, yet its role in cancer is less understood. We analyzed OIP5-AS1 expression in oral tumors and in TCGA datasets. We observed overexpression of OIP5-AS1 in oral tumors (P < 0.001) and in tumors of epithelial origin from TCGA. OIP5-AS1 expression was strongly associated with undifferentiated tumors (P = 0.0038). In silico analysis showed miR-7 binding site is conserved in mouse and human OIP5-AS1. However, human NANOG 3'-UTR lost the binding site for hsa-miR-7a-3. Therefore, we screened for other miRNAs that can be sponged by OIP5-AS1 and identified six potential miRNAs and their downstream target genes. Expression analysis showed downregulation of miRNAs and upregulation of downstream target genes, particularly in undifferentiated tumors with high-level of OIP5-AS1 suggesting OIP5-AS1 could post-transcriptionally modulate the downstream target genes. Further, systematic epigenomic analysis of OIP5-AS1 promoter revealed binding motifs for MYC, NANOG and KLF4 suggesting that OIP5-AS1 could be transactivated by stemness-associated transcription factors in cancer. OIP5-AS1 overexpression in undifferentiated oral tumors may be suggestive of enhanced cancer stemness, and consequently, poor clinical outcome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Base Sequence
  • Binding Sites
  • Carcinoma / genetics
  • Carcinoma / pathology
  • Cell Line, Tumor
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Kruppel-Like Factor 4
  • Male
  • MicroRNAs / genetics
  • Middle Aged
  • Models, Biological
  • Mouth Neoplasms / genetics*
  • Mouth Neoplasms / mortality
  • Mouth Neoplasms / pathology*
  • Neoplasm Grading
  • Neoplasm Invasiveness
  • Neoplasm Staging
  • Neoplastic Stem Cells / metabolism*
  • Neoplastic Stem Cells / pathology
  • Prognosis
  • RNA Interference
  • RNA, Long Noncoding / genetics*
  • Transcription Factors

Substances

  • KLF4 protein, human
  • Klf4 protein, mouse
  • Kruppel-Like Factor 4
  • MicroRNAs
  • RNA, Long Noncoding
  • Transcription Factors
  • long noncoding RNA OIP5, human