Cisplatin induces cell cycle arrest and senescence via upregulating P53 and P21 expression in HepG2 cells.
OBJECTIVE
Cellular senescence as one of the important steps against tumor is observed in many cancer patients receiving chemotherapy and is related to chemotherapeutic response. To investigate the effect of cisplatin on hepatocellular carcinoma, we treated HepG2 cells exhibiting wild-type TP53 with gradient concentrations of cisplatin.


METHODS
The inhibitory effects of cisplatin on human hepatoma HepG2 cells were detected by MTT assay and colony formation test. The changes in cell cycle were analyzed by flow cytometry, and cellular senescence was detected with senescence associated β-galactosidase (SA β-gal) staining. The relative mRNA expression levels of TP53, P21 and P19 was estimated using semi-quantitative real-time RT-PCR, and the protein expressions of P53 and P21 were detected using Western blotting.


RESULTS
Cisplatin induced irreversible proliferation inhibition and G1 phase arrest of HepG2 cells. Elevated levels of senescence-associated β-galactosidase was observed in HepG2 cells exposed to low doses of cisplatin. P19 expression immediately increased following cisplatin exposure and reached the maximum level at 48 h, followed then by a rapid decrease to the baseline level, whereas the expressions levels of TP53 and P21 mRNA increased continuously. Western blotting confirmed P53 and P21 expression changes similar to their mRNA expressions during cisplatin-induced cellular senescence in HepG2 cells.


CONCLUSIONS
Our results revealed a functional link between cisplatin and hepatocellular senescence. Cellular senescence induced by cisplatin as a stabile senescent cellular model can be used for further research.
Department of Hepatobiliary Surgery, First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, Xi'an 710061, China.E-mail: joanne8601@163.com.
Kai
K
Qu
Ting
T
Lin
Jichao
J
Wei
Fandi
F
Meng
Zhixin
Z
Wang
Zichao
Z
Huang
Yong
Y
Wan
Sidong
S
Song
Sinan
S
Liu
Hulin
H
Chang
Yafeng
Y
Dong
Chang
C
Liu
D002453:Cell Cycle / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D016922:Cellular Senescence; D002945:Cisplatin / Q000494:pharmacology*; D050764:Cyclin-Dependent Kinase Inhibitor p19 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D015854:Up-Regulation
C493956:CDKN1A protein, human; C493974:CDKN2D protein, human; D050764:Cyclin-Dependent Kinase Inhibitor p19; D050759:Cyclin-Dependent Kinase Inhibitor p21; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D002945:Cisplatin