Induction of p21(WAF1/CIP1) by human synovial sarcoma-associated chimeric oncoprotein SYT-SSX1

Oncogene. 2005 Dec 1;24(54):7984-90. doi: 10.1038/sj.onc.1208942.


Oncogenic protein provokes cell cycle arrest termed premature senescence. In this process Ras has been known to induce cyclin-dependent kinase inhibitor (CKI) p16(INK4A) in primary fibroblasts. Here, we present a novel finding that human chimeric oncoprotein SYT-SSX1 induces CKI p21(WAF1/CIP1) (p21) for suppression of cell growth. In human synovial sarcoma cell lines, the expression levels of p21 were high and the transcriptional activity of the p21 gene promoter was significantly elevated. The transient expression of SYT-SSX1-induced activation of the p21 gene promoter in human diploid fibroblasts. The N-terminus deletion form of SYT-SSX1, which failed to bind to hBRM one of the chromatin remodeling factors, preserved the p21 induction ability. This effect of SYT-SSX1 was similar in extent in both wild-type and p53-deficient HCT116 cell lines. Furthermore, the introduction of mutation in Sp1/Sp3 binding sites of the p21 gene promoter abolished the SYT-SSX1-induced transcriptional activity of its promoter. In SW13 cells, the stable expression of SYT-SSX1 suppressed cell growth in culture. These results suggest that SYT-SSX1 is able to induce p21 in a manner independent on hBRM and p53 but dependent on Sp1/Sp3.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Cell Line
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Cyclin-Dependent Kinase Inhibitor p21 / genetics
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Genes, Reporter
  • Green Fluorescent Proteins / metabolism
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Luciferases / metabolism
  • Mice
  • Microscopy, Confocal
  • NIH 3T3 Cells
  • Oncogene Proteins, Fusion / metabolism
  • Promoter Regions, Genetic
  • Recombinant Fusion Proteins / metabolism
  • Sarcoma, Synovial / genetics*
  • Sarcoma, Synovial / pathology


  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Oncogene Proteins, Fusion
  • Recombinant Fusion Proteins
  • SYT-SSX fusion protein
  • Green Fluorescent Proteins
  • Luciferases