Differentiation-inducing action of 10-hydroxycamptothecin on human hepatoma Hep G2 cells.
OBJECTIVE
To study the mechanism of differentiation-inducing action of 10-hydroxycamptothecin (HCPT) on human hepatoma Hep G2 cells.


METHODS
The proliferating cell nuclear antigen (PCNA) expression was studied by immunocytochemical staining method. The cell cycle distribution and the wild-type protein p53 expression were measured by flow cytometry. Telomerase activity was assayed with telomeric repeat amplification protocol (TRAP).


RESULTS
After treatment with HCPT at differentiation-inducing concentrations 5-20 micrograms.L-1 for 6 d, Hep G2 cells were mainly arrested at G2/M phase and the PCNA expression rate was lower than that of control cells. When Hep G2 cells grew in a medium containing HCPT 5 micrograms.L-1 for 6 d, the p53 expression level markedly increased in comparison with the control cells. The telomerase activity did not change in Hep G2 cells treated with HCPT 5-20 micrograms.L-1 for 8 d.


CONCLUSIONS
The differentiation-inducing effect of HCPT on Hep G2 cells is related with the cell cycle arrest at G2/M phase, down-regulation of PCNA and up-regulation of wild-type protein p53.
Zhang
X W
XW
Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200031, China.
Jiang
J F
JF
Xu
B
B
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000972:Antineoplastic Agents, Phytogenic; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; C028098:10-hydroxycamptothecin; D019098:Telomerase; D002166:Camptothecin