Down-regulated proteins of mesenchymal tumor cells

Exp Cell Res. 1998 Feb 25;239(1):161-8. doi: 10.1006/excr.1997.3896.


To identify proteins that are lost during the establishment of the transformed phenotype of a tumor cell, we have prepared a subtracted cDNA library with mRNA from normal human fibroblasts and from their matched SV40 transformed counterparts. More than 40 clones were obtained that showed a dramatic reduction in their relative expression after oncogenic transformation. The proteins encoded by these clones could be grouped into four distinct classes: extracellular matrix proteins (fibronectin, beta ig-h3, collagen VI), enzymes (collagenase, urokinase), cytoskeletal proteins (vinculin, SM22) and regulatory proteins (beta-glycan, integrin-associated protein, myosin kinase, IGFBP-5). Six novel gene products were discovered during these experiments, including a novel serine protease, a zyxin-like protein, an ankyrin-like protein and a GTP-binding protein. Only four of all the transformation-sensitive cDNAs were consistently down-regulated when a variety of cell lines derived from spontaneous mesenchymal tumors was investigated: beta ig-h3, collagen VI, the novel ankyrin-like protein, and IGFBP-5. It is likely that these gene products play an important role in the maintenance of the normal phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Cytoskeletal Proteins / biosynthesis
  • Enzymes / biosynthesis
  • Extracellular Matrix Proteins / biosynthesis
  • Gene Expression Regulation, Neoplastic*
  • Gene Library
  • Humans
  • Lung / cytology
  • Lung / metabolism
  • Mesenchymoma / metabolism*
  • Mice
  • Molecular Sequence Data
  • Neoplasm Proteins / biosynthesis*
  • Neoplasm Proteins / chemistry
  • RNA, Messenger / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Tumor Cells, Cultured


  • Cytoskeletal Proteins
  • Enzymes
  • Extracellular Matrix Proteins
  • Neoplasm Proteins
  • RNA, Messenger

Associated data

  • GENBANK/AJ001487