title: Murine P-glycoprotein on stromal vessels mediates multidrug resistance in intracerebral human glioma xenografts.
abstract: Human glioma usually shows intrinsic multidrug resistance because of the blood-brain barrier (BBB), in which membrane-associated P-glycoprotein (P-gp), encoded by the human multidrug resistance gene MDR1, plays a role. We studied drug sensitivity to vincristine (VCR), doxorubicin (DOX) and nimustine (ACNU) in both intracerebrally and subcutaneously xenotransplanted human glioma. We examined the levels of MDR1 and murine mdr3 gene expression in the xenografts by reverse transcriptase polymerase chain reaction and the localization of P-gp by immunohistochemistry. Six of seven subcutaneously transplanted xenografts (scX) were sensitive to the above three drugs. In contrast, all three intracerebrally transplanted human glioma xenografts (icX) were resistant to P-gp-mediated drugs VCR and DOX, but were sensitive to the non-P-gp-mediated drug ACNU. Neither icX nor scX showed any MDR1 expression. Intracerebrally transplanted human glioma xenografts showed an increased level of murine mdr3 gene expression, whereas scX showed only faint expression. The localization of P-gp was limited to the stromal vessels in icX by immunohistochemistry, whereas scX expressed no P-gp. Our findings suggest that the P-gp expressed on the stromal vessels in icX is a major contributing factor to multidrug resistance in human glioma in vivo.
authors.affiliation: Department of Neurosurgery, Tokai University School of Medicine, Kanagawa, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takamiya
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Tsugu
authors.forename: M
authors.initials: M
authors.lastname: Kazuno
authors.forename: Y
authors.initials: Y
authors.lastname: Oshika
authors.forename: K
authors.initials: K
authors.lastname: Maruo
authors.forename: Y
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: O
authors.initials: O
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: H
authors.initials: H
authors.lastname: Kijima
authors.forename: Y
authors.initials: Y
authors.lastname: Ueyama
authors.forename: N
authors.initials: N
authors.lastname: Tamaoki
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D000328:Adult; D000818:Animals; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D018432:Drug Resistance, Multiple; D005260:Female; D005910:Glioma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009368:Neoplasm Transplantation; D014183:Transplantation, Heterologous
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1