The functional characterization of long noncoding RNA SPRY4-IT1 in human melanoma cells

Oncotarget. 2014 Oct 15;5(19):8959-69. doi: 10.18632/oncotarget.1863.


Expression of the long noncoding RNA (lncRNA) SPRY4-IT1 is low in normal human melanocytes but high in melanoma cells. siRNA knockdown of SPRY4-IT1 blocks melanoma cell invasion and proliferation, and increases apoptosis. To investigate its function further, we affinity purified SPRY4-IT1 from melanoma cells and used mass spectrometry to identify the protein lipin 2, an enzyme that converts phosphatidate to diacylglycerol (DAG), as a major binding partner. SPRY4-IT1 knockdown increases the accumulation of lipin2 protein and upregulate the expression of diacylglycerol O-acyltransferase 2 (DGAT2) an enzyme involved in the conversion of DAG to triacylglycerol (TAG). When SPRY4-IT1 knockdown and control melanoma cells were subjected to shotgun lipidomics, an MS-based assay that permits the quantification of changes in the cellular lipid profile, we found that SPRY4-IT1 knockdown induced significant changes in a number of lipid species, including increased acyl carnitine, fatty acyl chains, and triacylglycerol (TAG). Together, these results suggest the possibility that SPRY4-IT1 knockdown may induce apoptosis via lipin 2-mediated alterations in lipid metabolism leading to cellular lipotoxicity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics*
  • Carnitine / biosynthesis
  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • Diacylglycerol O-Acyltransferase / biosynthesis
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Lipid Metabolism / genetics
  • Melanoma / genetics*
  • Neoplasm Invasiveness / genetics
  • Nerve Tissue Proteins / genetics*
  • Nuclear Proteins / metabolism*
  • RNA Interference
  • RNA, Long Noncoding / biosynthesis
  • RNA, Long Noncoding / genetics*
  • RNA, Small Interfering
  • Triglycerides / biosynthesis


  • Intracellular Signaling Peptides and Proteins
  • LPIN2 protein, human
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • RNA, Long Noncoding
  • RNA, Small Interfering
  • SPRY4 protein, human
  • Triglycerides
  • DGAT2 protein, human
  • Diacylglycerol O-Acyltransferase
  • Carnitine