title: Comparative serum albumin interactions and antitumor effects of Au(III) and Ga(III) ions.
abstract: In the present study, interactions of Au(III) and Ga(III) ions on human serum albumin (HSA) were studied comparatively via spectroscopic and thermal analysis methods: UV-vis absorbance spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and isothermal titration calorimetry (ITC). The potential antitumor effects of these ions were studied on MCF-7 cells via Alamar blue assay. It was found that both Au(III) and Ga(III) ions can interact with HSA, however; Au(III) ions interact with HSA more favorably and with a higher affinity. FT-IR second derivative analysis results demonstrated that, high concentrations of both metal ions led to a considerable decrease in the α-helix content of HSA; while Au(III) led to around 5% of decrease in the α-helix content at 200μM, it was around 1% for Ga(III) at the same concentration. Calorimetric analysis gave the binding kinetics of metal-HSA interactions; while the binding affinity (Ka) of Au(III)-HSA binding was around 3.87×10(5)M(-1), it was around 9.68×10(3)M(-1) for Ga(III)-HSA binding. Spectroscopy studies overall suggest that both metal ions have significant effects on the chemical structure of HSA, including the secondary structure alterations. Antitumor activity studies on MCF7 tumor cell line with both metal ions revealed that, Au(III) ions have a higher antiproliferative activity compared to Ga(III) ions.
authors.affiliation: UNAM-Institute of Materials Science & Nanotechnology, Bilkent University, Ankara 06800, Turkey.
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Sarioglu
authors.affiliation: UNAM-Institute of Materials Science & Nanotechnology, Bilkent University, Ankara 06800, Turkey.
authors.forename: Ayse
authors.initials: A
authors.lastname: Ozdemir
authors.affiliation: Gazi University Life Sciences Application and Research Center, Ankara 06830, Turkey.
authors.forename: Kuddusi
authors.initials: K
authors.lastname: Karaboduk
authors.affiliation: Gazi University Life Sciences Application and Research Center, Ankara 06830, Turkey; Gazi University, Department of Medical Biology and Genetics, Faculty of Medicine, 06500, Besevler, Ankara, Turkey. Electronic address: ttekinay@gazi.edu.tr.
authors.forename: Turgay
authors.initials: T
authors.lastname: Tekinay
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002151:Calorimetry; D016923:Cell Death / Q000187:drug effects; D005708:Gallium / Q000494:pharmacology*; D006046:Gold / Q000494:pharmacology*; D006801:Humans; D007477:Ions; D061986:MCF-7 Cells; D011485:Protein Binding / Q000187:drug effects; D012709:Serum Albumin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D000970:Antineoplastic Agents; D007477:Ions; D012709:Serum Albumin; D006046:Gold; D005708:Gallium
keywords: Au(III) ions; Chemical modifications; Ga(III) ions; Human serum albumin; Protein secondary structures