Chk2 kinase is required for methylglyoxal-induced G2/M cell-cycle checkpoint arrest: implication of cell-cycle checkpoint regulation in diabetic oxidative stress signaling.
Methylglyoxal (MG) is a reactive endogenous metabolite that is produced from the process of degradation of triose-phosphates. Under hyperglycemic conditions the rate of MG formation increases as a result of elevated concentrations of precursors. It has been established that MG elicits oxidative stress signaling, leading to the activation of MAP kinases, p38 MAPK and JNK, yet it remains largely unknown about a role of cell-cycle checkpoint regulation in MG-induced signaling. Here, we show that checkpoint kinases, Chk1 and Chk2, as well as their upstream ATM kinase are phosphorylated and activated following MG treatment of cultured cells. This MG-induced activation of Chk1 and Chk2 were inhibited by either aminoguanidine (AG), an inhibitor of production of advanced glycation end products (AGEs) or N-acetyl-l-cysteine (NAC), an anti-oxidant in dose dependent manners, indicating that oxidative stress via AGEs is involved critically in the activation of Chk1 and Chk2 by MG. Furthermore, it was found that cell-cycle synchronized cells exhibited G(2)/M checkpoint arrest following MG treatment, and that siRNA-mediated knock-down of Chk2, but not Chk1, results in a failure of MG-induced G(2)/M arrest. Thus, the results indicate a critical role for Chk2 in MG-induced G(2)/M cell-cycle checkpoint arrest.
Kani
Shuichi
S
Department of Physiology and Cell Biology, Faculty of Medical Sciences, Graduate School of Medicine, Kobe University, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Nakayama
Emiko
E
Yoda
Akinori
A
Onishi
Nobuyuki
N
Sougawa
Nagako
N
Hazaka
Yuki
Y
Umeda
Tsuyoshi
T
Takeda
Kohsuke
K
Ichijo
Hidenori
H
Hamada
Yasuhiro
Y
Minami
Yasuhiro
Y
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000111:Acetylcysteine / Q000494:pharmacology; D002460:Cell Line; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D003920:Diabetes Mellitus / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D016195:G2 Phase / Q000187:drug effects*; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D007700:Kinetics; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D050527:Mesangial Cells / Q000187:drug effects / Q000201:enzymology; D008938:Mitosis / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011765:Pyruvaldehyde / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D006146:Guanidines; D034741:RNA, Small Interfering; D011765:Pyruvaldehyde; D000080242:8-Hydroxy-2'-Deoxyguanosine; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D003849:Deoxyguanosine; C004479:pimagedine; D000111:Acetylcysteine