Transforming growth factor β-induced cell cycle arrest of human hematopoietic cells requires p57KIP2 up-regulation

Joseph M. Scandura, Piernicola Boccuni, Joan Massagué, Stephen D. Nimer

Research output: Contribution to journalArticlepeer-review

185 Scopus citations


Transforming growth factor β (TGFβ) is one of few known negative regulators of hematopoiesis, yet the mechanisms by which it affects cell cycle arrest and stem cell quiescence are poorly understood. Induction of the cyclin-dependent kinase inhibitors, p15INK4b (p15) and p21WAF1 (p21) is important for TGFβ-mediated cytostasis in epithelial cells but not in hematopoietic cells. Using primary human hematopoietic cells and microarray analysis, we identified p57KIP2 (p57) as the only cyclin-dependent kinase inhibitor induced by TGFβ. Up-regulation of p57 mRNA and protein occurs before TGFβ-induced G1 cell cycle arrest, requires transcription, and is mediated via a highly conserved region of the proximal p57 promoter. The up-regulation of p57 is essential for TGFβ-induced cell cycle arrest in these cells, because two different small interfering RNAs that prevent p57 up-regulation block the cytostatic effects of TGFβ on human hematopoietic cells. Reduction of basal p57 expression by this approach also allows hematopoietic cells to proliferate more readily in the absence of TGFβ. p57 is a putative tumor suppressor gene whose expression is frequently silenced by promoter hypermethylation in hematologic malignancies. Our studies identify a molecular pathway by which TGFβ mediates its cytostatic effects on human hematopoietic cells and suggests an explanation for the frequent silencing of p57 expression.

Original languageEnglish (US)
Pages (from-to)15231-15236
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 19 2004
Externally publishedYes


  • Cyclin-dependent kinase inhibitor
  • Negative regulators
  • Transcription control

ASJC Scopus subject areas

  • Genetics
  • General


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