The tumor suppressor hSNF5/INI1 modulates cell growth and actin cytoskeleton organization

Cancer Res. 2004 May 15;64(10):3406-13. doi: 10.1158/0008-5472.CAN-03-3004.

Abstract

hSNF5/INI1, which encodes a component of the ATP-dependent chromatin remodeling hSWI-SNF complex, is a tumor suppressor gene mutated in malignant rhabdoid tumors. We have developed a tetracycline-based hSNF5/INI1-inducible system in a hSNF5/INI1-deficient malignant rhabdoid tumor cell line and studied time course variation of 22,000 genes/expressed sequence tags upon hSNF5/INI1 induction. A total of 482 responsive genes were identified and further clustered into 9 groups of coregulated genes. Among genes with early and strong inductions, the use of a fusion protein with the hormone-binding domain of the estrogen receptor enabled the identification of a subset of direct targets regulated independently of de novo protein synthesis. We show that the G(1) arrest induced by hSNF5/INI1 is reversible and associated with the down-regulation of components of the DNA replication complex. We also identify an unsuspected role of hSNF5/INI1 in cytoskeleton organization. Indeed, induction of hSNF5/INI1 induces dramatic modifications of the cell shape including complete disruption of the actin stress fiber network and disappearance of focal adhesions associated with up-regulation of genes involved in the organization of the actin cytoskeleton. We document a strong decrease of Rho activity upon hSNF5/INI1 expression, suggesting that the regulation of this activity constitutes a crucial step of the hSNF5/INI1-induced reorganization of the actin network. This study identifies hSNF5/INI1 target genes and provides evidence that hSNF5/INI1 may modulate the cell cycle control and cytoskeleton organization through the regulation of the retinoblastoma protein-E2F and Rho pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Actins / physiology*
  • Amino Acid Sequence
  • Cell Division / genetics
  • Cell Line, Tumor
  • Chromosomal Proteins, Non-Histone
  • Cytoskeleton / metabolism
  • Cytoskeleton / physiology*
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Gene Expression Profiling
  • Genes, Tumor Suppressor
  • Humans
  • Molecular Sequence Data
  • Rhabdoid Tumor / genetics
  • Rhabdoid Tumor / metabolism
  • Rhabdoid Tumor / pathology
  • SMARCB1 Protein
  • Transcription Factors
  • rho GTP-Binding Proteins / antagonists & inhibitors
  • rho GTP-Binding Proteins / metabolism

Substances

  • Actins
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • SMARCB1 Protein
  • SMARCB1 protein, human
  • Transcription Factors
  • rho GTP-Binding Proteins