Zinc chloride stimulates DNA synthesis of mouse embryonic stem cells: involvement of PI3K/Akt, MAPKs, and mTOR.
Although zinc is one of the most important trace elements in the body, the mechanisms underlying zinc-induced cell proliferation have yet to be unraveled. Thus, we investigated the effect of zinc chloride (ZnCl(2)) on mouse embryonic stem (ES) cell proliferation and related signaling pathways. ZnCl(2) (40 microM) significantly increased [(3)H]-thymidine incorporation after 12 h of treatment. At moderate concentrations (> or =4 microM), ZnCl(2) increased cell cycle regulatory protein levels, [(3)H]-thymidine incorporation, and total cell numbers, but higher doses of ZnCl(2) (> or =200 microM) blocked this proliferative effect. ZnCl(2) induced the phosphorylation of Akt, c-Jun N-terminal kinases/stress-activated protein kinases (JNK/SAPK), p44/42 MAPKs, and mammalian target of rapamycin (mTOR) in a time-dependent manner. Pretreatment of LY 294002 (a PI3K inhibitor, 10(-6) M), wortmannin (a PI3K inhibitor, 10(-7) M), or an Akt inhibitor (10(-5) M), which inhibited the activation of JNK/SAPK and p44/42 MAPKs, blocked the ZnCl(2)-induced expression of cyclins and cyclin-dependent kinases (CDKs). Furthermore, pretreatment with PD 98059 (a p44/42 inhibitor, 10(-5) M) or SP 600125 (a JNK inhibitor, 10(-6) M) inhibited ZnCl(2)-induced activation of mTOR, p70S6K, and 4E-BP1. In addition, rapamycin (an mTOR inhibitor, 10(-8) M) blocked the ZnCl(2)-induced increase in [(3)H]-thymidine incorporation and cell cycle regulatory protein expression. In conclusion, ZnCl(2) stimulated ES cell proliferation through the PI3K/Akt, p44/42 MAPKs, JNK/SAPK, and mTOR signal pathways.
Ryu
Jung Min
JM
Department of Veterinary Physiology, College of Veterinary Medicine, Biotherapy Human Resources Center (BK21), Chonnam National University, Gwangju, Korea.
Lee
Min Young
MY
Yun
Seung Pil
SP
Han
Ho Jae
HJ
D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases; D017967:Zinc Compounds / Q000494:pharmacology*
D018797:Cell Cycle Proteins; D002712:Chlorides; D004247:DNA; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D011494:Protein Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D017967:Zinc Compounds; C016837:zinc chloride; C546842:MTOR protein, human; C546843:mTOR protein, mouse