title: Measurement of imatinib uptake by flow cytometry.
abstract: One of the essential parameters of targeted therapy efficiency in cancer treatment is the amount of drug reaching the therapeutic target area. Imatinib (IM) was the first specifically targeted drug to be developed and has revolutionized the treatment of patients with chronic myeloid leukemia (CML). To evaluate cellular uptake of IM, we developed a method based on the chemical structure of the molecule and using the natural UV fluorescence that we quantified by flow cytometry. In two CML cell lines, we obtained a satisfactory relationship between intracellular IM (ICIM) levels and media concentrations, and we found a strong correlation between ICIM at 1 h and IM efficacy at 24 h, demonstrating that ICIM at 1 h might be a relevant predictive parameter of cell sensitivity. Our method was more sensitive than the standard physicochemical method. We applied our method to primary cells and found cell morphology-dependent IM accumulation. Moreover, in CML cells from patients at diagnosis, IM accumulation was heterogeneous. In all cases, ICIM at the single-cell level was much higher than in culture media arguing in favor of a predominantly active uptake process. We developed a simple method directly applicable to primary cells that has shown two major advantages: only a small number of cells are required, and cell subsets can be identified according to morphological criteria and/or the presence of particular antigenic sites. This method provides a new tool to assess CML cell sensitivity to IM, and ICIM levels in native CML cells could be used to monitor therapeutic response.
authors.affiliation: Hématologie Biologique, CHU Estaing, Clermont-Ferrand Cedex 1, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Bourgne
authors.forename: Mahchid
authors.initials: M
authors.lastname: Bamdad
authors.forename: Alexandre
authors.initials: A
authors.lastname: Janel
authors.forename: Frédéric
authors.initials: F
authors.lastname: Libert
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Gagnieu
authors.forename: Chantal
authors.initials: C
authors.lastname: Rapatel
authors.forename: Pascale
authors.initials: P
authors.lastname: Pigeon
authors.forename: Sylvie
authors.initials: S
authors.lastname: Pereira
authors.forename: Eric
authors.initials: E
authors.lastname: Hermet
authors.forename: Agnès
authors.initials: A
authors.lastname: Guerci
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.forename: Pascale Cony
authors.initials: PC
authors.lastname: Makhoul
authors.forename: Atchroue Johnson
authors.initials: AJ
authors.lastname: Ansah
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Cahn
authors.forename: Denis
authors.initials: D
authors.lastname: Guyotat
authors.forename: Sébastien
authors.initials: S
authors.lastname: Trouillier
authors.forename: Juliette
authors.initials: J
authors.lastname: Berger
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boiret-Dupré
authors.forename: Marc G
authors.initials: MG
authors.lastname: Berger
mesh_terms: D000970:Antineoplastic Agents / Q000493:pharmacokinetics; D001549:Benzamides; D048430:Cell Shape; D003470:Culture Media / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D005434:Flow Cytometry / Q000379:methods*; D005453:Fluorescence; D006801:Humans; D000068877:Imatinib Mesylate; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000378:metabolism*; D010879:Piperazines / Q000097:blood / Q000493:pharmacokinetics*; D011743:Pyrimidines / Q000097:blood / Q000493:pharmacokinetics*; D012680:Sensitivity and Specificity; D014466:Ultraviolet Rays
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D003470:Culture Media; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate