The interaction of cinchonine and immunoglobulin G and the development of a nanocomplex with improved anti-breast cancer activity

Abstract

In this study we evaluated the interaction of cinchonine (Cin) and immunoglobulin G (IgG). Then, Cin-IgG nanoparticles (NPs) were synthesized and characterized. Finally, the anticancer effects of free Cin and Cin-IgG NPs on MCF-7 breast cancer (BC) cells were evaluated. The results of spectroscopy measurements show that the IgG-Cin complex's quenching mechanism is static and the structure of IgG was partially changed following interaction with Cin. The prepared Cin-IgG NPs display a hydrodynamic size of 190 nm with a PDI of 0.269, a zeta potential of −38.05 mV, an EE% of 72.38 %, a LC% of 5.41 %, and a pH-sensitive drug release behavior. In the cellular assay, it was found that the calculated IC50 concentrations of Cin, IgG NPs, and Cin-IgG NPs are 66.4 ± 5.39, >100, and 29.2 ± ± 4.11 μM, respectively, in MCF-7 BCE cells. Finally, Cin-IgG NPs induce a greater effect on the overexpression of the Bax/Bcl-2 ratio and downregulation of PI3K/p-AKT compared to the free drug. In conclusion, this study shows that Cin has the potential to bind IgG as a human plasma protein, and its complexation into a NP form with IgG can boost its anti-BC effects.