title: [Antisense oligonucleotide reverses topotecan-resistant ovarian cancer cells].
abstract: OBJECTIVE
  Breast cancer resistance protein (BCRP) was overexpressed in topotecan (TPT)-selected human ovarian cancer cell line A2780/TPT, strongly suggesting BCRP to be responsible for the drug-resistance of ovarian cancer. The current study was designed to investigate the reversal effect of BCRP antisense oligonucleotide (ASODN) on topotecan- resistant A2780/TPT cells.
  
  
  METHODS
  The antisense-phosphorothioate oligonucleotide including the translation initiation site of BCRP mRNA was artificially synthesized, and the sense oligonucleotide (SODN) corresponding to the ASODN was also synthesized as control. Lipofect-2000 (LF) was used for the transfer of either ASODN or SODN into A2780/TPT cells. The changes of BCRP mRNA expression, intracellular fluorescence intensity of rhodamine and resistance index to topotecan of in vitro transfected A2780/TPT cells were detected respectively by reverse transcription-polymerase chain reaction (RT-PCR),flow cytometry (FCM),and methyl thiazolyl tetrazolium (MTT) assay.
  
  
  RESULTS
  The transfer of ASODN/LF into A2780/TPT cells resulted in:(1)a 59.42% reduction of BCRP mRNA level (P< 0.05); (2)an obviously increased intracellular rhodamine fluorescence intensity from 5.42 to 16.63(P< 0.05); (3)a decreased resistance index to topotecan from 25 to 5 indicating sensitivity to topotecan in A2780/TPT cells recovered, as compared with non-transfected cell. But after transfecting SODN, no significant change could be measured.
  
  
  CONCLUSIONS
  ASODN transfection may partly reverse BCRP-mediated drug- resistance of ovarian cancer cells.
authors.affiliation: Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Jia
authors.forename: Shao-Bo
authors.initials: SB
authors.lastname: Wu
authors.forename: Qian
authors.initials: Q
authors.lastname: Xu
authors.forename: Ming-Fu
authors.initials: MF
authors.lastname: Wu
authors.forename: Qing-Lei
authors.initials: QL
authors.lastname: Gao
authors.forename: Guo-Ning
authors.initials: GN
authors.lastname: Liao
authors.forename: Yun-Ping
authors.initials: YP
authors.lastname: Lu
authors.forename: Ding
authors.initials: D
authors.lastname: Ma
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors* / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology*; D004347:Drug Interactions; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010051:Ovarian Neoplasms / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D019772:Topotecan / Q000494:pharmacology*; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D019772:Topotecan