[Effect of norcantharidin's derivative Nd3 on proliferation of human ovarian cancer cell line SKOV3 and its possible mechanisms].
OBJECTIVE
Norcantharidin (NCTD), the demethylated form of cantharidin, can inhibit the proliferation of many kinds of cancer cells, but its effect is milder than those of other drugs. This study was to explore the inhibitory effect of Nd3, a derivative of norcantharidin, on the proliferation of human ovarian cancer cell line SKOV3, compare its antitumor effect with that of norcantharidin, and investigate its possible molecular mechanisms.


METHODS
SKOV3 cells were treated with Nd3 and norcantharidin, separately. Cell proliferation was evaluated by sulforhodamine B (SRB) assay. Cell cycle distribution and apoptosis were detected by flow cytometry. The expression of Cdc2, Cyclin B1, Bax, and Bcl-2 was detected by Western blot.


RESULTS
When treated with 2.5, 5, 10, 20, 30, and 40 micromol/L Nd3 for 48 h, the inhibition rates of SKOV3 cells were 27.3%, 34.1%, 53.3%, 64.3%, 83.3%, and 96.7%, respectively, which were significantly higher than that of negative control cells (P<0.001). The 50% inhibition concentration of Nd3 was (25.1+/-2.3) micromol/L at 24 h, (21.8+/-2.8) micromol/L at 36 h, and (20.4+/-3.3) micromol/L at 48 h. When treated with 10, 20, 30, and 40 micromol/L Nd3 for 48 h, SKOV3 cells were arrested at G2/M phase at rates of 14.3%, 20.2%, 26.2%, and 27.9%; when treated with 30 micromol/L Nd3 for 12, 24, 36, and 48 h, the proportions of SKOV 3 cells at G2/M phase were 19.8%, 26.6%, 27.8%, and 32.0%. When treated with 40 micromol/L Nd3 for 48 h, the apoptosis rate of SKOV3 cells was significantly higher than that of control cells [(17.9+/-4.4)% vs. (2.5+/-2.8)%, P<0.01]. After treatment of Nd3, the expression of Cdc2, Cyclin B1, and Bcl-2 were down-regulated, and the expression of Bax was up-regulated.


CONCLUSIONS
Nd3 inhibits SKOV3 cell proliferation more than norcantharidin does, blocks cell cycle at G2/M phase, and induces apoptosis. The antitumor mechanism of Nd3 is related to the changes of Cdc2, Cyclin B1, Bax, and Bcl-2 expression.
Cao
Jing-Hua
JH
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Science, Peking University, Beijing, 100083, PR China.
Xu
Bo
B
Li
Min
M
Wu
De-Zhu
DZ
Huang
Wei
W
Cui
Jing-Rong
JR
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D019926:Cyclin B / Q000378:metabolism; D018844:Cyclin-Dependent Kinases; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D019926:Cyclin B; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; C069741:norcantharidin; D016203:CDC2 Protein Kinase; C528899:CDK1 protein, human; D018844:Cyclin-Dependent Kinases