The Biological Effects of C/EBP alpha in K562 Cells Depend on the Potency of the N-terminal Regulatory Region, Not on Specificity of the DNA Binding Domain

Giovanna Ferrari-Amorotti, Samanta Antonella Mariani, Chiara Novi, Sara Cattelani, Luisa Pecorari, Francesca Corradini, Angela Rachele Soliera, Gloria Manzotti, Valentina Fragliasso, Ying Zhang, Robert V. Martinez, Eric W. -F. Lam, Clara Guerzoni*, Bruno Calabretta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The transcription factor C/EBP alpha is more potent than C/EBP beta in inducing granulocitic differentiation and inhibiting BCR/ABL-expressing cells. We took a "domain swapping" approach to assess biological effects, modulation of gene expression, and binding to C/EBP alpha-regulated promoters by wild-type and chimeric C/EBP alpha/C/EBP beta proteins. Wild-type and N-C/EBP alpha+ C/EBP beta-DBD induced transcription of the granulocyte-colony stimulating factor receptor (G-CSFR) gene, promoted differentiation, and suppressed proliferation of K562 cells vigorously; instead, wild-type C/EBP beta and N-C/EBP beta+C/EBP alpha-DBD had modest effects, although they bound the G-CSFR promoter like wild-type C/EBP alpha and N-C/EBP alpha+C/EBP beta-DBD. Chimeric proteins consisting of the TAD of VP16 and the DBD of C/EBP alpha or C/EBP beta inhibited proliferation and induced differentiation of K562 cells as effectively as wild-type C/EBP alpha. Gene expression profiles induced by C/EBP alpha resembled those modulated by N-C/EBP alpha+C/EBP beta-DBD, whereas C/EBP beta induced a pattern similar to that of N-C/EBP beta+C/EBP alpha-DBD. C/EBP alpha activation induced changes in the expression of more cell cycle- and apoptosis-related genes than the other proteins and enhanced Imatinib-induced apoptosis of K562 cells. Expression of FOXO3a, a novel C/EBP alpha-regulated gene, was required for apoptosis but not for differentiation induction or proliferation inhibition of K562 cells.

Original languageEnglish
Pages (from-to)30837-30850
Number of pages14
JournalJournal of Biological Chemistry
Volume285
Issue number40
DOIs
Publication statusPublished - 1 Oct 2010

Keywords

  • ACUTE MYELOID-LEUKEMIA
  • ABL-EXPRESSING CELLS
  • GRANULOCYTIC DIFFERENTIATION
  • TRANSCRIPTION FACTOR
  • PROTEIN-ALPHA
  • HEMATOPOIETIC-CELLS
  • INITIATING CELLS
  • DOWN-REGULATION
  • IN-VIVO
  • GENE

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