Loss of novel mda-7 splice variant (mda-7s) expression is associated with metastatic melanoma

J Invest Dermatol. 2004 Sep;123(3):583-8. doi: 10.1111/j.0022-202X.2004.23321.x.


Expression of melanoma differentiation associated gene-7 (mda-7) also known as interleukin 24 (IL-24) decreases during melanoma cell differentiation and induces apoptosis in melanoma cells but not in melanocytes. Here we identify a novel splice variant of the cancer growth suppressor gene mda-7/IL-24 (mda-7s) that is differentially expressed in RNA preparations from normal human melanocytes, transformed melanocytes, nevi, subcutaneous metastasis, lymph node metastasis, and melanoma cell lines. The 450 bp mda-7s mRNA encodes a protein of 63 residues with a molecular weight of 12 kDa. mda-7s lacks exons 3 and 5 of the full-length transcript and contains only 14 amino acids of homology to MDA-7 located within the signal peptide region of the wild-type sequence. Despite minimal homology, MDA-7S coprecipitates full length MDA-7 and reduces secretion of cotransfected MDA-7. mda-7 and mda-7s are coexpressed in all RNA preparations other than subcutaneous and lymph node metastasis where mda-7s expression is lacking. mda-7s expression is therefore linked to a non-metastatic phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing*
  • Amino Acid Sequence
  • Base Sequence
  • Cell Line, Transformed
  • Cell Line, Tumor
  • Dimerization
  • Gene Expression Regulation, Neoplastic
  • Genes, Tumor Suppressor
  • Humans
  • Interleukins / chemistry
  • Interleukins / genetics*
  • Lymphatic Metastasis
  • Melanocytes / cytology
  • Melanocytes / physiology
  • Melanoma / genetics*
  • Melanoma / secondary
  • Molecular Sequence Data
  • Phenotype
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology


  • Interleukins
  • interleukin-24

Associated data

  • GENBANK/AY237723