Overexpression of NP95 mRNA by tumor promoters in the promotion phase of a two-stage BALB/3T3 cell transformation assay.
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.
Sakai
Ayako
A
Division of Microbiology, National Institute of Health Sciences, Japan. asakai@nihs.go.jp
Kikuchi
Yutaka
Y
Muroi
Masashi
M
Masui
Tohru
T
Furihata
Chie
C
Uchida
Eriko
E
Takatori
Kohsuke
K
Tanamoto
Ken-Ichi
K
D000818:Animals; D041702:BALB 3T3 Cells; D001973:Bromodeoxyuridine / Q000378:metabolism; D022762:CCAAT-Enhancer-Binding Proteins; D002273:Carcinogens / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D019976:Cloning, Organism / Q000379:methods; D015870:Gene Expression / Q000187:drug effects*; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D011838:Radiation-Sensitizing Agents / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D044767:Ubiquitin-Protein Ligases
D022762:CCAAT-Enhancer-Binding Proteins; D002273:Carcinogens; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011838:Radiation-Sensitizing Agents; D044767:Ubiquitin-Protein Ligases; C117054:Uhrf1 protein, mouse; D001973:Bromodeoxyuridine