Selective Cytotoxicity of 1,3,4-Thiadiazolium Mesoionic Derivatives on Hepatocarcinoma Cells (HepG2)

Abstract

In this work, we evaluated the cytotoxicity of mesoionic 4-phenyl-5-(2-Y, 4-X or 4-X-cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride derivatives (MI-J: X=OH, Y=H; MI-D: X=NO2, Y=H; MI-4F: X=F, Y=H; MI-2,4diF: X=Y=F) on human hepatocellular carcinoma (HepG2), and non-tumor cells (rat hepatocytes) for comparison. MI-J, M-4F and MI-2,4diF reduced HepG2 viability by ~ 50% at 25 μM after 24-h treatment, whereas MI-D required a 50 μM concentration, as shown by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The cytotoxicity was confirmed with lactate dehydrogenase assay, of which activity was increased by 55, 24 and 16% for MI-J, MI-4F and MI-2,4diF respectively (at 25 μM after 24 h). To identify the death pathway related to cytotoxicity, the HepG2 cells treated by mesoionic compounds were labeled with both annexin V and PI, and analyzed by flow cytometry. All compounds increased the number of doubly-stained cells at 25 μM after 24 h: by 76% for MI-J, 25% for MI-4F and MI-2,4diF, and 11% for MI-D. It was also verified that increased DNA fragmentation occurred upon MI-J, MI-4F and MI-2,4diF treatments (by 12%, 9% and 8%, respectively, at 25 μM after 24 h). These compounds were only weakly, or not at all, transported by the main multidrug transporters, P-glycoprotein, ABCG2 and MRP1, and were able to slightly inhibit their drug-transport activity. It may be concluded that 1,3,4-thiadiazolium compounds, especially the hydroxy derivative MI-J, constitute promising candidates for future investigations on in-vivo treatment of hepatocellular carcinoma.

C@PA: Computer-Aided Pattern Analysis to Predict Multitarget ABC Transporter Inhibitors

“… 63 , 64 1,3,4-Thiadiazoles have also only once been reported in association with selective, dual, or triple ABCB1, ABCC1, and ABCG2 inhibition. 66 However, these compounds had estimated IC 50 values of far beyond 25 μM. 66 Thieno[3,2- c ]pyridines, on the other hand, have never been associated with either ABCB1, ABCC1, or ABCG2.…”

“… 66 However, these compounds had estimated IC 50 values of far beyond 25 μM. 66 Thieno[3,2- c ]pyridines, on the other hand, have never been associated with either ABCB1, ABCC1, or ABCG2.…”

“…More strikingly, compounds 15 , 18 , 21 , 22 , and 26 belong to the structural classes of 1,2,4-oxadiazoles, 1,3,4-thiadiazoles, and thieno­[3,2- c ]­pyridines. While 1,2,5-oxadiazoles − have frequently been reported as (selective − or dual) ABCB1 ,, and ABCC1 inhibitors, , 1,2,4-oxadiazoles − have only once been reported as selective ABCG2 inhibitors or reversers of ABCB1-, ABCC1-, or ABCG2-mediated MDR. , 1,3,4-Thiadiazoles have also only once been reported in association with selective, dual, or triple ABCB1, ABCC1, and ABCG2 inhibition . However, these compounds had estimated IC 50 values of far beyond 25 μM .…”

Synthetic (E)-3-Phenyl-5-(phenylamino)-2-styryl-1,3,4-thiadiazol-3-ium Chloride Derivatives as Promising Chemotherapy Agents on Cell Lines Infected with HTLV-1

“…Thus, the difference observed between the effect of cytotoxicity in cells infected with HTLV-1 and Jurkat cells may be directly related to viral modulation in the synthesis of lipids and proteins. It is known that mesoionic compounds can interact with the DNA molecule and their biological activity can be related with this interaction [32,58]. Based on this, the interaction of compounds 5a-d with DNA was investigated using spectroscopic analysis.…”

“…In our previous studies with 1,3,4-thiadiazolium salts (mesoionic compounds) containing a substituted styryl moiety, important results for in vitro cytotoxic activity in various types of tumor cells, including leukemias [23,[32][33][34], and in vivo antitumor effects have been observed [35,36]. Besides, results on the antiviral activity of 1,3,4-thiadiazole derivatives against HIV-1 [37][38][39][40], which also belong to the same Retroviridae family, have also been reported in the literature.…”