A biophysical study on the mechanism of interactions of DOX or PTX with α-lactalbumin as a delivery carrier

Abstract

Doxorubicin and paclitaxel, two hydrophobic chemotherapeutic agents, are used in cancer therapies. Presence of hydrophobic patches and a flexible fold could probably make α-Lactalbumin a suitable carrier for hydrophobic drugs. In the present study, a variety of thermodynamic, spectroscopic, computational, and cellular techniques were applied to assess α-lactalbumin potential as a carrier for doxorubicin and paclitaxel. According to isothermal titration calorimetry data, the interaction between α-lactalbumin and doxorubicin or paclitaxel is spontaneous and the K (M−1) value for the interaction of α-lactalbumin and paclitaxel is higher than that for doxorubicin. Differential scanning calorimetry and anisotropy results indicated formation of α-lactalbumin complexes with doxorubicin or paclitaxel. Furthermore, molecular docking and dynamic studies revealed that TRPs are not involved in α-Lac’s interaction with Doxorubicin while TRP 60 interacts with paclitaxel. Based on Pace analysis to determine protein thermal stability, doxorubicin and paclitaxel induced higher and lower thermal stability in α-lactalbumin, respectively. Besides, fluorescence lifetime measurements reflected that the interaction between α-lactalbumin with doxorubicin or paclitaxel was of static nature. Therefore, the authors hypothesized that α-lactalbumin could serve as a carrier for doxorubicin and paclitaxel by reducing cytotoxicity and apoptosis which was demonstrated during our in vitro cell studies.

Functionalized Alpha‐lactalbumin Conjugated with Gold Nanoparticle for Targeted Drug Delivery

“…Contrary to this, Behdad et al. reported that there was a significant decrease in the α‐helix content in the interaction between ALA and docetaxel at 1 : 2 molar ratio . Similar trend was experienced for Cur interaction with AuNPs‐ALA.…”

“…In agreement with this, our findings suggest that the formation of ALA‐drug conjugates provides energy stabilization, which allows more weak interactions that can accommodate drug molecules on protein active site by helix conformation. Contrary to this, α‐LA‐paclitaxel complex was not seen to induce a significant change in α‐helicity . In case of AuNP‐ALA interaction with drugs, the magnitude of the MRE peaks at 208 and 222 nm decreases, suggesting pronounced changed in helicity.…”

“…Interestingly, we observed three transition states in the fluorescence spectrum named as the native state (25‐40 °C), the molten globule states (intermediate state, 40–65 °C) and the denatured state (65‐95 °C). We determined the melting temperature of the ALA and it was found to be 34.66 °C (Figure d), which is in agreement with previous report …”

“…Delavary et al. have hypothesized that ALA could serve as a drug delivery carrier for doxorubicin and paclitaxel by reducing cytotoxicity . Mohammadi et al.…”

α-Lactalbumin, Amazing Calcium-Binding Protein

“…α-LA interacts with doxorubicin (DOX) and paclitaxel (PTX), two hydrophobic chemotherapeutic agents, which are used in cancer therapies [ 186 ]. The binding constants of these substances measured by means of isothermal titration calorimetry are rather low (~10 4 M −1 ).…”