4‐Amino‐5‐benzoyl‐2‐(4‐methoxyphenylamino)thiazole (DAT1): a cytotoxic agent towards cancer cells and a probe for tubulin‐microtubule system

Abstract

1 Microtubule binding drugs are of special interest as they have important roles in the modulation of cellular functions and many of them act as anticancer agents. 4-Amino-5-benzoyl-2-(4-methoxyphenylamino)thiazole (DAT1) was identified as one of the active compounds from a series of diaminoketothiazoles in a cell-based screening assay to discover cytotoxic compounds. 2 DAT1 shows cytotoxicity with GI 50 values ranging from 0.05 to 1 mM in different malignant cell lines with an average value of 0.35 mM. It blocks mitosis in the prometaphase and metaphase stages. In HeLa cells, DAT1 blocks the spindle function by disturbing spindle microtubule and chromosome organization. 3 The drug also inhibits assembly of brain microtubules and binds tubulin specifically at a single site with induction of fluorescence. The dissociation constant of DAT1 binding to tubulin was determined as 2.971 mM at 241C. The binding site of DAT1 on tubulin overlaps with that of the conventional colchicine-binding site. 4 DAT1 can thus be considered as a lead compound of a new class of small molecules and this study can be used as a step to develop potent antimitotic agents for the control of cytoskeletal functions and cell proliferation. It would also be an interesting probe for the structure-function studies of tubulinmicrotubule system.

Diaminothiazoles Inhibit Angiogenesis Efficiently by Suppressing Akt Phosphorylation

“…2. DAT1 reduced cell viability by 50% after treatment for 48 h at a concentration of 4.47 Ϯ 0.99 M. This value is ϳ14 times higher than the cytotoxicity of DAT1 in a variety of human tumor cell lines (average IC 50 , 0.35 M) (Sengupta et al, 2005). DAT1 Inhibition of Invasion, Migration, and Cord Formation of HUVECs.…”

“…The lead compound, 4-amino-5-benzoyl-2-(4-methoxyphenylamino)thiazole (DAT1), was shown to bind tubulin at the colchicine binding site, causing mitotic arrest and cell death (Sengupta et al, 2005). The promising activity of CA4P and a few other tubulin-binding agents in clinical trials prompted us to study the antiangiogenic activity of diaminothiazoles.…”

Induction of apoptosis through tubulin inhibition in human cancer cells by new chromene-based chalcones

“…Tubulin was purified from sheep brain through two cycles of polymerization-depolymerization in the PEM buffer [100 mM PIPES, pH 6.9, 1mM MgSO 4 and 1 mM ethylene glycol tetraacetic acid (EGTA)], according to the method described by Sengupta et al (2005). Then microtubule-associated proteins (MAPs)-free tubulin were purified from the microtubule protein by DEAE chromatography aliquots and stored in liquid nitrogen when not in use (Murphy et al, 1977).…”

Reversible Action of Diaminothiazoles in Cancer Cells Is Implicated by the Induction of a Fast Conformational Change of Tubulin and Suppression of Microtubule Dynamics

“…The lead compound of this class, DAT1 (structure given in Fig. 1), binds to the colchicine-binding site of tubulin with exhibition of fluorescence (14). However, unlike colchicine, DAT1 binding is fast.…”

“…Diaminothiazoles are novel cytotoxic compounds that have shown efficacy toward different cancer cell lines (14,15). They block cells in the mitotic phase by destroying spindle structure and chromosome organization and inhibit microtubule assembly.…”