Covalently modified Thioredoxin fluorescent protein (Trx-APAO(AsIII)-FITC) affecting biophysical parameters of lipids

LIS FEMIA; FACUNDO TEMPRANA; SILVIA SOTO ESPINOSA; MARIANO GRASSELLI; SILVIA ALONSO

Beijing

Congreso; 17th International Biophysics Congress; 2011

IUPAB

Arsenic compounds are useful against different kinds of cancer, like promyelocitic acute leukemia. The bioconjugate between Trx and arsenic-fluorescent compound synthetized APAO-FITC (Femia et al, 2012) is as an alternative arsenic therapeutic agent. This present study shows the special features generated when Trx/APAO-FITC is encapsulated/associated with different lipid formulations. Properties like size, interaction with MC540 probe, Z potential and encapsulation efficiency are shown within a lipid concentration range of 1-10 mM. Results showed that Trx/APAO-FITC influenced the molecular probe MC540 apparent equilibrium dimerization constant (Kadd (dim)/(mon)e2). Data obtained for Kadd were in the range 10e(7) - 10e(6), presenting lower Kadd values as a function of Trx/APAO-FITC concentration. Encapsulation efficiency determinations percentage of drug incorporated into liposomes was between 10-70%. Hydrophobicity factor (HF) and MC540 partitioning results showed that the probe partitioned between aqueous phase and hydrophobic lipid side chains depending on Trx-APAO-FITC presence. The effect of Trx-APAO-FITC on different cell lines: HL60, HeLa and PBMC are able to produce apoptosis on leukemia cells more significantly than on PBMC. Protein As-shuttle association with lipid formulations resulted in greater cell apoptosis depending on cell line. Some lipid formulations led to cell proliferation, like SPC and DPPC:Chol.