title: Modulation of multidrug-resistance-associated P-glycoprotein in human U-87 MG and HUV-ECC cells with antisense oligodeoxynucleotides to MDR1 mRNA.
abstract: OBJECTIVE
  Glioblastoma is the highest dedifferentiated form of astrocytic brain tumors, and it is refractory to chemotherapy in most cases. To improve the clinical outcome of such tumors, new therapeutic strategies are needed. While malignancy is mainly associated with a nonfunctional apoptotic pathway, the lack of chemotherapeutic success correlates with overexpression of the multidrug resistance 1 (MDR1) gene product P-glycoprotein (P-gp). Previous investigations have shown that not only glioblastoma cells but also endothelial cells are important in the response to chemotherapy. The aim of the present investigations was to reduce the expression of P-gp in the human glioblastoma cell line U-87 MG and in the human endothelial cell line HUV-ECC.
  
  
  METHODS
  Therefore, these cells were treated with antisense oligodeoxynucleotides (asn-ODN) directed against the P-gp mRNA in order to increase the intracellular retention of doxorubicin (DOX) which had been given previously.
  
  
  RESULTS
  Flow cytometry revealed about 4-fold increased intracellular retention of DOX in both asn-ODN-treated cell lines as compared to asn-ODN non-treated cell lines.
  
  
  CONCLUSIONS
  These results suggest that asn-ODN-mediated inhibition of P-gp expression is an efficient way to increase intracellular retention of DOX.
authors.affiliation: Department of Neurosurgery, Medical School of Hannover, Hannover, Germany. rittierodt.marion@mh-hannover.de
authors.forename: Marion
authors.initials: M
authors.lastname: Rittierodt
authors.forename: Thomas
authors.initials: T
authors.lastname: Tschernig
authors.forename: Kunyu
authors.initials: K
authors.lastname: Harada
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000378:metabolism / Q000494:pharmacology; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D019450:Genes, MDR / Q000235:genetics; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D004317:Doxorubicin