title: [Regulatory effect of small interfering RNA targeting multidrug resistant protein 1 on chemosensitivity of human multiforme glioblastoma cell line BT325].
abstract: OBJECTIVE
  Multidrug resistance is a major reason of failure of chemotherapy for glioma. Overexpression of P-glycoprotein (P-gp), encoded by multidrug resistant protein 1 (MDR1) gene, is one of the key factors. This study was to explore the regulatory effect of small interfering RNA (siRNA) targeting MDR1 on chemosensitivity of human multiforme glioblastoma cell line BT325.
  
  
  METHODS
  MDR1 siRNAs containing sequences of 3,051-3,069 (MDR1 A group), 502-520 (MDR1 B group), and 1,534-1,552 (MDR1 C group) were designed, and transfected into BT325 cells. Positive clones were screened with puromycin. The expression of MDR1 was measured by reverse transcription-polymerase chain reaction (RT-PCR); the expression of P-gp was detected by immunohistochemistry and flow cytometry (FCM). Drug sensitivity assay was performed in the transfected cells.
  
  
  RESULTS
  BT325 cells proliferated exponentially after MDR1 siRNA transfection. After transfection of MDR1 siRNAs, the expression of MDR1 mRNA was significantly lower in MDR1 A, B, and C groups than in control group (0.18+/-0.05, 0.30+/-0.09, and 0.36+/-0.13 vs. 0.76+/-0.06, P<0.001); the positive rate of P-gp was decreased from 85.73% to 1.44%; the 50% inhibitory concentrations (IC(50)) of doxorubicin and vincristine to BT325 cells were decreased markedly; the G0/G1 phase proportions of MDR1 A, B, and C groups were increased by 13.55%, 14.35%, and 1.46% of control, respectively (P<0.05).
  
  
  CONCLUSIONS
  MDR1 siRNA may modulate multidrug resistance through down-regulating the expression of MDR1 gene, enhancing the chemosensitivity of glioma, and inducing cell apoptosis.
authors.affiliation: Capital University of Medical Sciences, Beijing 100054, P. R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.forename: Ya-Zhuo
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Mei-Zhen
authors.initials: MZ
authors.lastname: Sun
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D010957:Plasmids; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection; D014750:Vincristine / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014750:Vincristine; D004317:Doxorubicin