Multidrug-resistant cancer cells contain two populations of P-glycoprotein with differently stimulated P-gp ATPase activities: evidence from atomic force microscopy and biochemical analysis - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochemical Journal Année : 2005

Multidrug-resistant cancer cells contain two populations of P-glycoprotein with differently stimulated P-gp ATPase activities: evidence from atomic force microscopy and biochemical analysis

Stéphane Barakat
  • Fonction : Auteur
Landry Gayet
  • Fonction : Auteur
Guila Dayan
  • Fonction : Auteur
Adina Lazar
  • Fonction : Auteur
  • PersonId : 753927
  • IdHAL : adina-lazar
Vladimir Oleinikov
  • Fonction : Auteur
Anthony Coleman
  • Fonction : Auteur
  • PersonId : 1030927
Loris Baggetto
Anthony w. Coleman
  • Fonction : Auteur
Loris g. Baggetto

Résumé

Considerable interest exists about the localization of P-gp (P-glycoprotein) in DRMs (detergent-resistant membranes) of multidrug resistant cancer cells, in particular concerning the potential modulating role of the closely related lipids and proteins on P-gp activity. Our observation of the opposite effect of verapamil on P-gp ATPase activity from DRM and solubilized-membrane fractions of CEM-resistant leukaemia cells, and results from Langmuir experiments on membrane monolayers from resistant CEM cells, strongly suggest that two functional populations of P-gp exist. The first is located in DRM regions: it displays its optimal P-gp ATPase activity, which is almost completely inhibited by orthovanadate and activated by verapamil. The second is located elsewhere in the membrane; it displays a lower P-gp ATPase activity that is less sensitive to orthovanadate and is inhibited by verapamil. A 40% cholesterol depletion of DRM caused the loss of 52% of the P-gp ATPase activity. Cholesterol repletion allowed recovery of the initial P-gp ATPase activity. In contrast, in the solubilized-membrane-containing fractions, cholesterol depletion and repletion had no effect on the P-gp ATPase activity whereas up to 100% saturation with cholesterol induced a 58% increased P-gp ATPase activity, while no significant modification was observed for the DRM-enriched fraction. DRMs were analysed by atomic force microscopy: 40-60% cholesterol depletion was necessary to remove P-gp from DRMs. In conclusion, P-gp in DRMs appears to contain closely surrounding cholesterol that can stimulate P-gp ATPase activity to its optimal value, whereas cholesterol in the second population seems deprived of this function.

Dates et versions

hal-01848902 , version 1 (25-07-2018)

Identifiants

Citer

Stéphane Labialle, Stéphane Barakat, Landry Gayet, Guila Dayan, Adina Lazar, et al.. Multidrug-resistant cancer cells contain two populations of P-glycoprotein with differently stimulated P-gp ATPase activities: evidence from atomic force microscopy and biochemical analysis. Biochemical Journal, 2005, 388 (2), pp.563 - 571. ⟨10.1042/BJ20041999⟩. ⟨hal-01848902⟩
19 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More