[Disfigurement of p16INK4A gene expression in development of ovarian cancer and the mechanism].
OBJECTIVE
To evaluate the expression of p16INK4A gene in ovarian cancer and analyze the relation between this alteration and the promoter methylation of p16INK4A DNA.


METHODS
The expression of p16INK4A mRNA was detected with RT-PCR in ovarian cancer cell lines and tissues, and the protein was detected by western blot. Methylation specific PCR (MSP) was used to check whether it was methylated in the promoter of p16INK4A, and normal ovarian tissues were used as control. The demethylating agent, 5-aza-2'-deoxycytidine, was used to treat methylated ovarian cancer cells and then, ovarian cancer cell growth was measured in vivo and in vitro.


RESULTS
Three ovarian cancer cell lines (Anglne, SW626, OVCAR3) and six ovarian cancer specimens were found methylated in p16INK4A DNA; the methylation rate was 3/7 and 33% (6/18) in ovarian cancer cell lines and specimens respectively. All the methylated cell lines and ovarian cancer tissues expressed decreasing p16INK4A mRNA and protein. Compared with the control, both the expression of p16INK4A mRNA and protein were decreased significantly or absolutely deleted in ovarian cancer cells (P < 0.05). The decrease was partly due to the methylation of p16INK4A. 5-aza-2'-deoxycytidine could reactivate the expression of p16INK4A in methylated cells and decrease the cell growth in vivo and in vitro.


CONCLUSIONS
The disfigurement of p16INK4A gene plays an important role in the development of ovarian cancer, and this alteration is partially caused by methylation of p16INK4A DNA.
Li
Min
M
Department of Obstetrics and Gynecology, Union Hospital of Tongji Medical College, Huazhong Science and Technology University, Wuhan 430022, China.
Huang
Zai-ju
ZJ
Dong
Wei-hong
WH
Li
Xiao-yan
XY
Wang
Xiao-yi
XY
He
Xiao-hong
XH
Wang
Han
H
Wang
Ze-hua
ZH
D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis / Q000235:genetics*; D019175:DNA Methylation; D000077209:Decitabine; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009366:Neoplasm Seeding; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000473:pathology / Q000517:prevention & control; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D047368:Tumor Burden; D023041:Xenograft Model Antitumor Assays
D000964:Antimetabolites, Antineoplastic; D019941:Cyclin-Dependent Kinase Inhibitor p16; D012333:RNA, Messenger; D000077209:Decitabine; D001374:Azacitidine