[The mechanism of topotecan resistance in ovarian cancer cell line].
OBJECTIVE
To study the mechanism of topotecan (TPT) resistance in ovarian cancer cell line.


METHODS
A TPT-resistant ovarian cancer cell line A2780/TPT established in this laboratory was used in this study. Intracellular rhodamine fluorescence intensity of the TPT-resistant cells and parental cells were measured by flow cytometry. The gene expression of membrane protein transporter such as transporter P-glycoprotein (P-gp), multidrug resistance associated protein (MRP), breast cancer resistance protein (BCRP) was evaluated by RT-PCR. The antisense-phosphorothioate oligonucleotide (ASODN) including a translation initiation site of BCRP mRNA was transferred into resistant cells by liposome.


RESULTS
Intracellular rhodamine fluorescence intensity of the resistant cells was 31.19% of that in the parental cells (P < 0.01). No expression of P-gp was demonstrated, and that of MRP was very weak in the TPT-resistant cells (relative expression value = 0.057). BCRP was overexpressed in the TPT-resistant cells (relative expression = 0.66), but not in the parental cells. Transfer of ASODN into resistant cells resulted in a 59.42% reduction of BCRP gene expression (P < 0.05) and an obviously increased intracellular rhodamine fluorescence intensity from 5.42 to 16.63 (P < 0.05).


CONCLUSIONS
The overexpression of BCRP which mediated drug efflux may play an important role in the induction of TPT-resistance in ovarian cancer.
Jia
Ping
P
Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Wu
Shao-Bo
SB
Li
Fang
F
Xu
Qian
Q
Wu
Ming-Fu
MF
Liao
Guo-Ning
GN
Lu
Yun-Ping
YP
Ma
Ding
D
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D019772:Topotecan / Q000494:pharmacology*
C116614:ABCG2 protein, human; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D019772:Topotecan