title: ABC transporters as differentiation markers in glioblastoma cells.
abstract: Glioblastoma multiforme (GBM) is the most common primary malignant brain tumour, characterized by a high aggressivity, a huge heterogeneity attending a hierarchical model and resistance to therapy. Drug resistance has been correlated with the presence of the ABC efflux transporters which are able to exclude drugs for the cellular cytoplasm. In the nucleus of the GBM, initiating cells (ICs) can self-renew and give rise to cancer stem cells, which differ to the side population cells and the different cellular subtypes that form the mass around them. The ICs do not express or express ATP binding cassette (ABC) at very low levels, but this expression may increase with the differentiation process. We suggest that the differentiation process may be responsible of chemoresistance of the GBM cells. We compared three ABC transporters expression: ABCA1, MRP4 and MRP5, in the ICs obtained from 9 patients with GBM and their respective differentiated GBM cells. We show an overexpression of the three ABC transporters in the differentiated GBM cells in comparison to ICs.
  
  
  CONCLUSIONS
  The blockade of these ABC transporters could help to improve the drug effectivity and thus reduce the tumour growth and prevent the tumour recurrence.
authors.affiliation: Department of Health Sciences, University of Jaen, Campus Las Lagunillas, s/n, 23071, Jaen, Spain, arama@ujaen.es.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Rama
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Alvarez
authors.forename: Roberto
authors.initials: R
authors.lastname: Madeddu
authors.forename: Antonia
authors.initials: A
authors.lastname: Aranega
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000502:physiology; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D017931:DNA Primers; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C577836:ABCA1 protein, human; C073492:ABCC4 protein, human; C120809:ABCC5 protein, human