title: Molecular and functional MDR1-Pgp and MRPs expression in human glioblastoma multiforme cell lines.
abstract: The aim of our study was to investigate the functional expression of P-glycoprotein (Pgp) and multidrug resistance-associated proteins (MRPs) in 2 distinct glioma cells (GL15 and 8MG) from patients with glioblastoma multiforme. MDR1 gene and Pgp expression was not detected in either cell line by RT-PCR and Western blotting, respectively. In contrast, MRP1 was detected at both mRNA and protein level in both cell lines, with a higher expression in the 8MG cells that occur predominantly at the cell membrane. Three other MRPs (MRP3, MRP4 and MRP5) were detected by RT-PCR in both cell lines, whereas MRP2 was not expressed. In addition, MRP3 protein was also detected by immunocytochemistry in both GL15 and 8MG cell lines. Indomethacin and probenecid, 2 modulators of MRPs activity, increased the accumulation of vincristine and etoposide, 2 substrates of MRPs, by both cell lines. These modulators also decreased the efflux of vincristine from both cell lines with a more pronounced effect in 8MG cells. In conclusion, our results show functional expression of MRPs leading to a decrease in the intracellular vincristine and etoposide concentrations in human glioblastoma cell lines. Furthermore, our results that exhibit protein expression of MRP1 and MRP3 and gene expression of MRP4 and MRP5 in these 2 glioblastoma cell lines suggest new mechanisms that could lead to a MDR phenotype of tumour cells in patients with glioblastoma multiforme.
authors.affiliation: INSERM U26, Hôpital F. Widal, Paris, France. xavier.decleves@fr.netgrs.com
authors.forename: Xavier
authors.initials: X
authors.lastname: Declèves
authors.forename: Anne
authors.initials: A
authors.lastname: Fajac
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lehmann-Che
authors.forename: Marcienne
authors.initials: M
authors.lastname: Tardy
authors.forename: Claire
authors.initials: C
authors.lastname: Mercier
authors.forename: Ilse
authors.initials: I
authors.lastname: Hurbain
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Laplanche
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Bernaudin
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Scherrmann
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism; D001692:Biological Transport; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005047:Etoposide / Q000378:metabolism; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D012334:RNA, Neoplasm / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D014750:Vincristine / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D005047:Etoposide; D005904:Glial Fibrillary Acidic Protein; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012334:RNA, Neoplasm; D014750:Vincristine; C114462:multidrug resistance-associated protein 3; C421109:multidrug resistance-associated protein 1