[Apoptosis of nasopharyngeal carcinoma cells induced by topoisomerase I inhibitor].
OBJECTIVE
To determine if the topoisomerase I inhibitor Camptothecin (CPT) can induce apoptosis in vitro in a human nasopharyngeal carcinoma (NPC) cell line with low differentiation (CNE-2Z).


METHODS
The light microscopy, flow cytometry and agarose gel electrophoresis were used to examine the morphological changes, cell cycle distribution, hypodiploid cells and DNA fragmentation.


RESULTS
After exposure to CPT for a certain period, CNE-2Z cells underwent obvious morphological changes with characteristics of apoptosis such as decrease in cell volumes condensation of chromatin and the formation of apoptotic bodies. Flow cytometry (FCM) test showed that when CNE-2Z cells were treated with 2-10 mumol/L CPT for 12 or 24 hours, hypodiploid cells accounted for 30% and 50% respectively. Cell cycle analysis by FCM revealed that changes in CNE-2Z cell cycle distribution were apparent 24 hours after treatment with various doses of CPT, showing no obvious dose-dependent relationship. Compared with controls, the percentage of cells in G2/M phase decreased markedly while those in G1 and S phases increased moderately.


CONCLUSIONS
The results demonstrated that DNA topoisomerase I inhibitor Camptothecin can induce apoptosis in CNE-2Z cells in vitro.
Zhang
Q
Q
Institute of Medical Biochemistry, Gungdong Medical College, Zhanjiang.
Zhou
K
K
Ling
G
G
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002166:Camptothecin / Q000494:pharmacology*; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D059004:Topoisomerase I Inhibitors; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D059004:Topoisomerase I Inhibitors; D002166:Camptothecin