Similarity of the DNA-damage responsiveness and growth-suppressive properties of WAF1/CIP1 and GADD45

Q. Zhan, W. El-Deiry, I. Bae, I. Alamo, M. B. Kastan, B. Vogelstein, A. Fornace

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


The cellular responses to genotoxic stress are complex involving both p53-dependent and independent mechanisms. In the case of the GADD genes, many stresses eliciting growth arrest have been shown to induce these genes in a coordinate fashion regardless of p53 status, while the ionizing radiation response (IR) of GADD45 has been found to be strictly p53-dependent. In the current study, the response of GADD45 was compared to the p53-regulated genes WAF1/CIP1 and MDM2 in a panel of human lines with known p53 status and also in mouse embryo fibroblasts where one or both alleles of p53 had been deleted. After IR, all 3 genes showed very similar transcriptional responses as measured by rapid increases in mRNA in a p53-dependent manner. Like GADD45, the WAF1/CIP1 induction by IR can be enhanced by the radiosensitizer iododeoxyuridine, and provides further evidence that DNA strand breaks can act as a signal for activation of the p53 pathway. In addition, caffeine, which blocks IR cell-cycle checkpoint activation, reduced IR induction for both genes. Unlike the case for IR, only WAF1/CIP1 showed a consistent similarity to GADD45 to DNA base-damaging agents, where appreciable induction occurred in cells regardless of p53 status. The similarity between WAF1/CIP1 and GADD45 also extended to their growth suppressive properties, and a combination of expression vectors for these genes suppressed growth appreciably more than either alone. A reasonable interpretation of these results is that growth suppression after DNA damage by either p53-dependent or independent pathways is mediated by the combined action of multiple downstream effecters including WAF1/CIP1 and GADD45.

Original languageEnglish (US)
Pages (from-to)937-946
Number of pages10
JournalInternational journal of oncology
Issue number5
StatePublished - Jan 1 1995
Externally publishedYes


  • Caffeine
  • DNA damage
  • Ionizing radiation
  • MDM2
  • Methylmethane sulfonate
  • Ultraviolet radiation
  • p53

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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