Identification and characterization of tubulin as Ga(III)-binding protein in T24 cells

Abstract

Gallium-based metallic drugs and agents have been widely applied for the diagnosis and treatment of diseases such as non-Hodgkin's lymphoma (NHL), but there are few reports on the potential Ga(III)-binding proteins and the related cytotoxic mechanisms for Ga(III). Herein, by using human urinary bladder cancer T24 cells as a model, we identify and report that tubulin is a Ga(III)-binding protein target in T24 cells. Our analyses, including the employment of a series of methods based on immobilized metal affinity chromatography (IMAC), cellular thermal shift assay (CETSA), and immunofluorescence experiments, collectively explained this finding. Our results suggest that the binding of Ga(III) to tubulin led to significant changes in the morphology and distribution of microtubules in cells. The blocked microtubule formation or microtubule depolymerization as a result of the binding of Ga(III) to tubulin may be an important molecular mechanism by which Ga(III) exerts its cytotoxic effects in T24 cells to inhibit tumor cell growth.