MAP kinase-independent induction of proto-oncogene c-fos mRNA by hemin in human cells.
Treatment of HeLa cells or human skin fibroblast cells with hemin led to a time- and dose-dependent rapid induction of c-fos mRNA. This induction was absent in the cells treated with actinomycin D, indicating that the c-fos induction by hemin occurs at the level of transcription. Metalloporphyrins, including zinc-, cobalt-, and tin-protoporphyrin, ferric ion, and protoporphyrin also induced c-fos mRNA. Transient reporter assay with the reporter constructs of the human c-fos gene promoter up to -404 bp connected to the luciferase gene showed high activity but no induction by hemin, suggesting that cis-acting elements, including the serum response element located about -310 bp upstream of the human c-fos gene promoter, may not contribute to the heme-dependent induction. With in-gel assay of protein kinases, the activity of the mitogen-activated protein (MAP) kinases such as extracellular signal-regulated kinase 12 or p38 MAP kinase in hemin-treated HeLa cells was not stimulated. Stimulation of c-Jun N-terminal kinase by hemin was nil. Furthermore, PD58059 and SB203580, inhibitors for MAP kinases, did not affect the hemin-dependent c-fos induction. Of the inhibitors for protein kinases so far tested, KN-62, a specific inhibitor for calmodulin-dependent protein kinase II (CaMK II), inhibited the induction of c-fos mRNA by hemin. Phosphorylation of CaMK II in hemin-treated cells increased. With gel mobility assay, the DNA AP-1 binding activity transiently increased when treating HeLa cells with hemin. Therefore, induction of c-fos led to an activation of AP-1 in the presence of hemin. We suggest that calmodulin-dependent protein kinase II rather than the MAP kinase family regulates the induction of the human c-fos gene expression by hemin.
Masuya
Y
Y
Second Department of Surgery, Department of Hygiene, Kansai Medical University, Moriguchi, Osaka, 570-8506, Japan.
Kameshita
I
I
Fujisawa
H
H
Kohno
H
H
Hioki
K
K
Tokunaga
R
R
Taketani
S
S
D018053:Arsenites / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D006367:HeLa Cells; D006427:Hemin / Q000502:physiology*; D006801:Humans; D007501:Iron / Q000494:pharmacology; D008665:Metalloporphyrins / Q000494:pharmacology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011524:Protoporphyrins / Q000494:pharmacology; D015398:Signal Transduction; D017670:Sodium Compounds / Q000494:pharmacology; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000502:physiology
D018053:Arsenites; D004791:Enzyme Inhibitors; C000715470:MAS1 protein, human; D008665:Metalloporphyrins; D019384:Nucleic Acid Synthesis Inhibitors; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos; D011524:Protoporphyrins; D017670:Sodium Compounds; D018808:Transcription Factor AP-1; D003609:Dactinomycin; C017947:sodium arsenite; D006427:Hemin; D007501:Iron; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002122:Calcium Chloride