article · 01/02/2007
The pH-dependent distribution of the photosensitizer chlorin e6 among plasma proteins and membranes: A physico-chemical approach
Résumé
Decrease in interstitial pH of the tumor stroma and over-expression of low density lipoprotein (LDL) receptors by several types of neoplastic cells have been suggested to be important determinants of selective retention of photosensitizers by proliferative tissues. The interactions of chlorin e6 (Ce6), a photosensitizer bearing three carboxylic groups, with plasma proteins and DOPC unilamellar vesicles are investigated by fluorescence spectroscopy. The binding constant to liposomes, with reference to the DOPC concentration, is 6 X 10(3) M-1 at pH 7.4. Binding of Ce6 to LDL involves about ten high affinity sites close to the apoprotein and some solubilization in the lipid compartment. The overall association constant is 5.7 X 10(7) M-1 at pH 7.4. Human serum albumin (HSA) is the major carrier (association constant 1.8 X 10(8) M-1 at pH 7.4). Whereas the affinity of Ce6 for LDL and liposomes increases at lower pH, it decreases for albumin. Between pH 7.4 and 6.5, the relative affinities of Ce6 for LDL versus HSA, and for membranes versus HSA, are multiplied by 4.6 and 3.5, respectively. These effects are likely driven by the ionization equilibria of the photosensitizer carboxylic chains. Then, the cellular uptake of chlorin e6 may be facilitated by its pH-mediated redistribution within the tumor stroma. (c) 2006 Elsevier B.V All rights reserved.
Citer cet article
Mojzisova, H., Bonneau, S., Vever-Bizet, C., & Brault, D. (2007). The pH-dependent distribution of the photosensitizer chlorin e6 among plasma proteins and membranes: A physico-chemical approach. Biochim Biophys Acta, 1768(2), 366-74. https://doi.org/10.1016/j.bbamem.2006.10.009@article{Mojzisova2007_160,
author = {Mojzisova, Halina and Bonneau, Stephanie and Vever-Bizet, Christine and Brault, Daniel},
year = {2007},
month = {2},
title = {The pH-dependent distribution of the photosensitizer chlorin e6 among plasma proteins and membranes: A physico-chemical approach},
journal = {Biochim Biophys Acta},
volume = {1768},
number = {2},
pages = {366-74},
abstract = {Decrease in interstitial pH of the tumor stroma and over-expression of low density lipoprotein (LDL) receptors by several types of neoplastic cells have been suggested to be important determinants of selective retention of photosensitizers by proliferative tissues. The interactions of chlorin e6 (Ce6), a photosensitizer bearing three carboxylic groups, with plasma proteins and DOPC unilamellar vesicles are investigated by fluorescence spectroscopy. The binding constant to liposomes, with reference to the DOPC concentration, is 6 X 10(3) M-1 at pH 7.4. Binding of Ce6 to LDL involves about ten high affinity sites close to the apoprotein and some solubilization in the lipid compartment. The overall association constant is 5.7 X 10(7) M-1 at pH 7.4. Human serum albumin (HSA) is the major carrier (association constant 1.8 X 10(8) M-1 at pH 7.4). Whereas the affinity of Ce6 for LDL and liposomes increases at lower pH, it decreases for albumin. Between pH 7.4 and 6.5, the relative affinities of Ce6 for LDL versus HSA, and for membranes versus HSA, are multiplied by 4.6 and 3.5, respectively. These effects are likely driven by the ionization equilibria of the photosensitizer carboxylic chains. Then, the cellular uptake of chlorin e6 may be facilitated by its pH-mediated redistribution within the tumor stroma. (c) 2006 Elsevier B.V All rights reserved.},
url = {http://www.dx.doi.org/10.1016/j.bbamem.2006.10.009},
doi = {10.1016/j.bbamem.2006.10.009},
issn = {0005-2736},
}TY - JOUR
AU - Mojzisova, Halina
AU - Bonneau, Stephanie
AU - Vever-Bizet, Christine
AU - Brault, Daniel
PY - 2007
DA - 2007/02/01
TI - The pH-dependent distribution of the photosensitizer chlorin e6 among plasma proteins and membranes: A physico-chemical approach
JO - Biochim Biophys Acta
VL - 1768
IS - 2
SN - 0005-2736
AB - Decrease in interstitial pH of the tumor stroma and over-expression of low density lipoprotein (LDL) receptors by several types of neoplastic cells have been suggested to be important determinants of selective retention of photosensitizers by proliferative tissues. The interactions of chlorin e6 (Ce6), a photosensitizer bearing three carboxylic groups, with plasma proteins and DOPC unilamellar vesicles are investigated by fluorescence spectroscopy. The binding constant to liposomes, with reference to the DOPC concentration, is 6 X 10(3) M-1 at pH 7.4. Binding of Ce6 to LDL involves about ten high affinity sites close to the apoprotein and some solubilization in the lipid compartment. The overall association constant is 5.7 X 10(7) M-1 at pH 7.4. Human serum albumin (HSA) is the major carrier (association constant 1.8 X 10(8) M-1 at pH 7.4). Whereas the affinity of Ce6 for LDL and liposomes increases at lower pH, it decreases for albumin. Between pH 7.4 and 6.5, the relative affinities of Ce6 for LDL versus HSA, and for membranes versus HSA, are multiplied by 4.6 and 3.5, respectively. These effects are likely driven by the ionization equilibria of the photosensitizer carboxylic chains. Then, the cellular uptake of chlorin e6 may be facilitated by its pH-mediated redistribution within the tumor stroma. (c) 2006 Elsevier B.V All rights reserved.
SP - 366
EP - 74
DO - 10.1016/j.bbamem.2006.10.009
UR - http://www.dx.doi.org/10.1016/j.bbamem.2006.10.009
ER -