Human melanoma cell line UV responses show independency of p53 function

Tarja Haapajärvi, Kimmo Pitkänen, Marikki Laiho

Research output: Contribution to journalArticlepeer-review

Abstract

UV radiation-induced mutation of the p53 gene is suggested as a causative event in skin cancer, including melanoma. We have analyzed here p53 mutations in melanoma cell lines and studied its stabilization, DNA-binding activity, and target gene activation by UVC. p53 was mutated in three of seven melanoma cell lines. However, high levels of p53 were detected in all cell lines, including melanoma cells with wild-type p53, with the exception of one line with a truncated form. Upon UV induction, p53 accumulated in lines with wild-type p53, and p53 target genes p21(Cip1/Waf1), GADD45, and mdm2 were induced, but the induction of p21(Cip1/Waf1) was significantly delayed as compared with the increase in p53 DNA-binding activity. However, despite p53' target gene induction, p53 DNA-binding activity was absent in one melanoma line with wild-type p53, and p53 target genes were induced also in cells with mutant p53. In response to UV, DNA replication ceased in all cell lines, and apoptosis ensued in four lines independently of p53 but correlated with high induction of GADD45. The results suggest that in melanoma, several p53 regulatory steps are dislodged; its basal expression is high, its activation in response to UV damage is diminished, and the regulation of its target genes p21(Cip1/Waf1) and GADD45 are dissociated from p53 regulation.

Original languageEnglish (US)
Pages (from-to)163-171
Number of pages9
JournalCell Growth and Differentiation
Volume10
Issue number3
StatePublished - Mar 1 1999
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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