Overexpression of NP95 mRNA by tumor promoters in the promotion phase of a two-stage BALB/3T3 cell transformation assay

Ayako Sakai, Yutaka Kikuchi, Masashi Muroi, Tohru Masui, Chie Furihata, Eriko Uchida, Kohsuke Takatori, Ken Ichi Tanamoto

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We studied altered gene expressions in BALB/3T3 cells treated by different tumor promoters in the promotion phase of a transformation assay, an in vitro model of a two-stage carcinogenicity test, using fluorescent mRNA differential display analysis. Expression of the NP95 gene, which was previously found to be the gene of a murine nuclear protein associated with cell proliferation, was increased in the cultures treated by 12-O-tetradecanoylphorbol-13-acetate (TPA), okadaic acid, and orthovanadate. The upregulation of NP95 mRNA was confirmed by reverse transcription-PCR, and Northern blot. TPA, okadaic acid, and orthovanadate enhanced cell proliferation as measured by a 5-bromo-2′- deoxyuridine incorporation assay. The expression level of NP95 mRNA was not affected by the treatment with typical carcinogens benzo[a]pyrene and 3-methylcholanthrene at concentrations at which they act as initiators of cell transformation. These facts may imply that the enhancement of cell transformation by these tumor promoters is due, at least in part, to the acceleration of cell proliferation. NP95 mRNA was also increased in the transformed BALB/3T3 cells. Overexpression of NP95 may also participate in the maintenance of the transformed phenotype.

Original languageEnglish
Pages (from-to)347-351
Number of pages5
JournalBiological and Pharmaceutical Bulletin
Issue number3
Publication statusPublished - 2003 Mar
Externally publishedYes


  • Cell transformation
  • Gene expression
  • NP95
  • Proliferation
  • Tumor promoter

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science


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