Antisense Inhibition of Chk2/hCds1 Expression Attenuates DNA Damage-Induced S and G2 Checkpoints and Enhances Apoptotic Activity in HEK-293 Cells

FEBS Lett. 2001 Sep 7;505(1):7-12. doi: 10.1016/s0014-5793(01)02756-9.

Abstract

The cellular response to DNA damage involves checkpoint controls that delay cell cycle progression in order to provide time for repair of damaged DNA. Chk2/hCds1 is a recently identified homolog of the yeast Cds1 kinase that is involved in cell cycle checkpoint response to DNA damage. To investigate the functions of Chk2/hCds1 in response to DNA damage in mammalian cells, we established a stable human kidney embryonic cell line (HEK-293) that expresses antisense Chk2/hCds1 (Chk2AS) under the control of an inducible promoter. Cells that express Chk2AS display defective S-phase delay in response to DNA replication-mediated DNA damage induced by the topoisomerase I inhibitor camptothecin. The defective G2 checkpoint was also observed in Chk2AS cells exposed to the DNA damaging agent VP-16 or gamma-radiation. Enhanced apoptosis was observed in Chk2AS cells after exposure to gamma-radiation or camptothecin. No p53 activation was observed after DNA damage in HEK-293 or Chk2AS cells. Our results indicate that perturbation of Chk2/hCds1 expression adversely affects the S- and G2-phase checkpoints following DNA damage or DNA replication block, and suggest that reduced expression of Chk2/hCds1 might promote a p53-independent apoptotic response.

MeSH terms

  • Apoptosis / genetics*
  • Cells, Cultured
  • Checkpoint Kinase 2
  • DNA Damage / physiology*
  • DNA, Antisense
  • G2 Phase / genetics*
  • Gene Expression Regulation
  • Humans
  • Kidney / cytology
  • Kidney / embryology
  • Protein Kinases / genetics*
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases*
  • S Phase / genetics*
  • Transfection
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • DNA, Antisense
  • Tumor Suppressor Protein p53
  • Protein Kinases
  • Checkpoint Kinase 2
  • CHEK2 protein, human
  • Protein-Serine-Threonine Kinases