[The activation of MAPK/cyclin D1-CDK4 signaling pathway caused by quartz].
OBJECTIVE
To study the phosphorylation level of mitogen activated protein kinase (MAPK) in human embryonic lung fibroblasts (HELF), and the expression level of cyclin D1-CDK4 protein in S-HELF and whether the expression level of cyclin D1-CDK4 protein mediated by MAPK/AP-1 signaling pathway in S-HELF.


METHODS
Two kinds of treatment: (1) Cells were harvested after stimulation 2 h for the detection of cytokines. (2) Cells were stimulated by quartz for a long time (2 months) for transformation characters (S-HELF). The MAP kinase was detected by western blot. Cyclin D1 and CDK4 (cyclin dependent kinase 4) proteins was measured by immunocytochemistry. Flow cytometry was used to evaluate the alternation of cell cycle.


RESULTS
Crystalline quartz could cause the phosphorylation level of ERKs, p38K, and JNKs in HELF increase. However, activated levels of ERKs and p46 of JNKs increased in S-HELF, and p38K activation decreased, and no effect on activation of p54 of JNKs, as compared with those in parental HELF. Cyclin D1 and CDK4 protein expression levels increased in S-HELF as compared with parental HELF. Inhibition of ERKs activation by AG126, AP-1 by curcumin, and JNKs by SP600125 could reduced the induction of cyclin D1 and CDK4, whereas inhibition of p38K by SB203580 did not show any inhibitory effects on S-HELF.


CONCLUSIONS
The phosphorylation levels of ERK1/2, JNK1/2, and p38 increased in HELF exposed to quartz. The phosphorylation levels of ERK1/2 and JNK1 increased, but the phosphorylation level of p38 decreased in S-HELF. The expression level of cyclin D1-CDK4 protein increased in S-HELF. Overexpression of cyclin D1-CDK4 is due to the activation of ERKs, JNKs/AP-1 signaling pathway in S-HELF.
Shen
Fu-Hai
FH
National Institute of Occupational Health and Poisons Control, Chinese Center for Disease Control and Prevention, Beijing, China.
Fan
Xue-Yun
XY
Liu
Bing-Ci
BC
Jia
Xiao-Wei
XW
Gao
Ai
A
You
Bao-Rong
BR
Ye
Meng
M
DU
Hong-Ju
HJ
Huang
Chuan-Shu
CS
Shi
Xiang-Lin
XL
D002460:Cell Line; D019938:Cyclin D1 / Q000378:metabolism*; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000166:cytology; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011791:Quartz / Q000633:toxicity*
C530104:CCND1 protein, human; D019938:Cyclin D1; D011791:Quartz; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D020928:Mitogen-Activated Protein Kinases