2-Methyl-1,4-naphthoquinone, vitamin K(3), decreases gap-junctional intercellular communication via activation of the epidermal growth factor receptor/extracellular signal-regulated kinase cascade.
2-Methyl-1,4-naphthoquinone, vitamin K(3) (menadione), which is frequently used as a model quinone in cell culture and in vivo studies, was tested for its effects on gap-junctional intercellular communication (GJC). Exposure of WB-F344 rat liver epithelial cells to menadione (50-100 micro M) led to a 50-75% decrease in GJIC. Different from the phorbol ester 12-O-tetradecanoylphorbol 13-acetate, menadione did not induce internalization of gap junctions. Rather, the decreased GJIC was found to be because of phosphorylation of connexin 43, the major connexin in the used cell line, which was mediated by MAPK/ERK kinase (MEK) 1 and MEK 2 as well as by activation of their direct substrates, extracellular signal-regulated kinase (ERK) 1 and ERK 2. Activation of ERK 1/2 was demonstrated to be independent of NAD(P)H:quinone oxidoreductase using the inhibitor dicoumarol, thus excluding redox cycling as the major mechanism causing these menadione effects. A substantial increase in tyrosine phosphorylation was detected in the cell membrane immunocytochemically upon exposure to menadione, consistent with arylation by menadione bearing the responsibility for the signaling events induced and consistent with the fact that protein tyrosine phosphatases are known targets of arylation reactions. ERK activation was attenuated using specific inhibitors of the epidermal growth factor receptor tyrosine kinase. Similarly, these inhibitors as well as inhibitors of MEK 1/2 counteracted the loss in gap-junctional communication elicited by menadione. This is of interest for chemotherapeutic approaches exploiting the bystander-effect, which is based upon intact GJIC.
Institut für Physiologische Chemie I, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany. larsoliver.klotz@uni-duesseldorf.de
Lars-Oliver
LO
Klotz
Pauline
P
Patak
Niloofar
N
Ale-Agha
Darius P
DP
Buchczyk
Kotb
K
Abdelmohsen
P Arne
PA
Gerber
Claudia
C
von Montfort
Helmut
H
Sies
D000818:Animals; D002450:Cell Communication / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D066246:ErbB Receptors / Q000502:physiology*; D017629:Gap Junctions / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D024483:Vitamin K 3 / Q000494:pharmacology*
D018031:Connexin 43; D024483:Vitamin K 3; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases