Synthesis and Anticancer Evaluation of Naphthoquinone Esters with 2′-Cyclopentyl and 2′-Cyclohexyl Substituents

Synthesis and antiproliferative evaluation of some 1,4-naphthoquinone derivatives against human cervical cancer cells

In the course of biological properties of quinone derivatives, the N(H)-, S- and S,S-substituted-1,4-naphthoquinones were synthesized by reactions of 2,3-dichloro-1,4-naphthoquinone with different amines (2-morpholinoaniline, tert-butyl 4-aminobenzoate, 4-tert-butylbenzylamine, N-(3-aminopropyl)-2-pipecoline, 2-amino-5,6-dimethylbenzothiazole, N,N'-diphenyl-p-phenylenediamine) and thiolat (sodium 2-methyl-2-propanethiolate). All new products were characterized by MS-ESI, UV-Vis, FT-IR, 1H NMR, 13C NMR. The antiproliferative activities of these compounds on human cervical cancer (HeLa) cells were evaluated by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. Although all derivatives inhibited cell growth, the most active compound was 2-(tert-butylthio)-3-chloronaphthalene-1,4-dione 5 (IC50=10.16 μM) against the HeLa cells.

Biophysical and molecular docking studies of naphthoquinone derivatives on the ATPase domain of human topoisomerase II

Numerous naphthoquinone derivatives, such as rhinacanthins function as anticancer drugs, which target hTopoII. The structure of hTopoII contains both an ATPase domain and a DNA binding domain. Several drugs bind to either one or both of these domains, thus modifying the activity of hTopoII. The naphthoquinone esters and amides used in this study showed that their hTopoIIα inhibitory activity was inversely proportional to ATP concentration. In order to better characterize the inhibitory action of these compounds, sufficient quantities of soluble functional hTopoII-ATPase domain were required. Therefore, both the alpha and beta isoforms of the hTopoII-ATPase domain were over-expressed in Escherichia coli. The hTopoIIα-ATPase activity was reduced in the presence of naphthoquinone derivatives. Additionally, a molecular docking study revealed that the selected naphthoquinone ester and amide bind to the ATP-binding domain of hTopoIIα. Collectively, the results here provide for the first time a novel insight into the interaction between naphthoquinone esters and amides, and the ATP-binding domain of hTopoIIα. The further elucidation of the mechanism of action of the naphthoquinone esters and amides inhibitory activity is essential.