Binding interactions of actinomycin D anticancer drug with bile salts micelles

The interactions of actinomycin D (ActD) anticancer drug with two bile salts of different hydrophobicity (sodium cholate (NaC) and sodium deoxycolate (NaDC) and the influence of these bile salts aggregates on the ActD- -DNA complex was investigated in 10 mM phosphate buffer (pH 7.4) by UV- -Vis spectroscopy (absorption and thermal denaturation). The binding strength of ActD to NaDC is higher than for NaC, and this difference attests stronger hydrophobic interactions between ActD and NaDC micelles. Also, the partition coefficient is significantly higher for NaDC micelles than for NaC micelles, in line with larger aggregates formed by NaDC. The spectral profile of ActD molecules in NaC and NaDC micelles, in comparison with different solvents, implies that ActD molecule experiences a hydrophobic environment in bile salts aggregates. Regarding the influence of NaC and NaDC aggregates on the ActD- DNA complex, it was shown that the presence of both bile salts micelles do not induce the deintercalation of ActD molecules from DNA duplex.