Determination of Hydroxycamptothecin Affinities to Albumin and Membranes by Steady-State Fluorescence Anisotropy Measurements

Title: Determination of Hydroxycamptothecin Affinities to Albumin and Membranes by Steady-State Fluorescence Anisotropy Measurements

Volume: 10 Issue: 6

Author(s): Blanka Ziomkowska, Michal Cyrankiewicz and Stefan Kruszewski

Affiliation:

Keywords: Camptothecin, fluorescence anisotropy, membranes, human serum albumin (HSA)

Abstract: Camptothecin (CPT) and its hydroxycamptothecin analogs are fluorescent compounds exhibiting strong anticancer properties. They exist in two forms: active lactone and inactive carboxylate. The deactivation proceeds via hydrolysis in neutral and base solutions. A serious limitation to the clinical application of CPT is the strong affinity of its carboxylate form to human serum albumin (HSA) which destabilizes its active lactone form. However, binding to membranes in blood improves the stability of the lactone form of CPT and its analogs. A high-throughput screening assay based on the steady-state fluorescence anisotropy method was used to determine the protein- and membrane-binding properties of 10-hydroxycamptothecin (10-OH-CPT), 7-ethyl-10-hydroxycamptothecin (SN-38) and 7-tertbutyldimethylsil- 10-hydroxycamptothecin (DB-67). The relative affinities of hydroxycamptothecins to HSA and model membranes in the form of DMPC liposomes were determined, and DB-67 exhibited the most desirable properties including the highest affinity to membranes in its lactone form and low affinity to HSA in its carboxylate form.

Cite this article as:

Ziomkowska Blanka, Cyrankiewicz Michal and Kruszewski Stefan, Determination of Hydroxycamptothecin Affinities to Albumin and Membranes by Steady-State Fluorescence Anisotropy Measurements, Combinatorial Chemistry & High Throughput Screening 2007; 10 (6) . https://dx.doi.org/10.2174/138620707781996420