Expression of multidrug-resistance P-glycoprotein (MDR1) in human brain tumors.
Multidrug resistance (MDR) is associated with the expression of P-glycoprotein (P-gp), an ATP-dependent transporter which expels anti-cancer drugs from cells. In the present study, MDR1 P-gp was immunodetected by Western blot analysis in 60 human brain tumors, including meningiomas, schwannomas, low-grade gliomas (astrocytomas, pilocytic astrocytomas) and high-grade gliomas (anaplastic astrocytomas, glioblastomas and anaplastic oligodendrogliomas). Most samples from primary tumors expressed P-gp at the same levels as normal brain tissue except for schwannomas, in which levels were reduced by 65%, and meningiomas, in which levels were more than 10-fold higher in 7 of 10 samples. P-gp levels were 70% and 95% lower in brain metastases from melanomas and lung adenocarcinomas, respectively, than in normal brain tissue. These results indicate that the majority of primary brain tumors express MDR1 P-gp and that its high expression levels in meningiomas may be a marker for this type of brain tumor.
Demeule
M
M
Laboratoire de Médecine Moléculaire, Hôpital Sainte-Justine-Université du Québec à Montréal, Montréal, Québec, Canada.
Shedid
D
D
Beaulieu
E
E
Del Maestro
R F
RF
Moghrabi
A
A
Ghosn
P B
PB
Moumdjian
R
R
Berthelet
F
F
Béliveau
R
R
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D001254:Astrocytoma / Q000737:chemistry; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000737:chemistry* / Q000556:secondary; D005909:Glioblastoma / Q000737:chemistry; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology; D008545:Melanoma / Q000473:pathology; D008579:Meningioma / Q000235:genetics; D009442:Neurilemmoma / Q000235:genetics; D009837:Oligodendroglioma / Q000737:chemistry; D012016:Reference Values
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1