Design and synthesis of new benzothiazole-piperazine derivatives and in vitro and in silico investigation of their anticancer activity

In this work, novel benzothiazole-piperazine acetamide (2a-2l) analogs were synthesized and evaluated their anticancer activity. The (HNMR)-H-1 , (CNMR)-C-13 and LC-MS/MS spectral data and elemental analyses were used to clarify the structure of the final molecules. The title compounds were procured by reacting 2-chloro-N-(6-substituted benzothiazole-2-yl) acetamide with some piperazine derivatives. Cytotoxicity and apoptosis parameters including Annexin V binding capacities, effect on cell cycle, caspase-3 activation and mitochondrial membrane depolarization effect were evaluated to determine anticancer profile of the final molecules on A549 (human lung adenocarcinoma), C6 (glioma cell line) and NIH/3T3 (mouse embryoblast cell line). Mostly, the final molecules showed significant cytotoxic profile with prominent selectivity. 2c (IC50: 7.23 +/- 1.17, SI: 6.93), 2d (IC50: 17.50 +/- 4.95; SI: 11.59), and 2 h (IC50: 10.83 +/- 0.76; SI: 29.23) showed significant and selective cytotoxic activity. Compounds 2b, 2c and 2e provoked apoptosis of A549 cells with potential higher than cisplatin as determined by flow cytometry. The cell cycle analysis of 2b, 2e, 2 g, and 2 h suggested that the A549 cells were affected during G0/G1 phase. Caspase-3 activation was observed on cells by compounds 2a, 2e, 2i and 2l at most. The highest mitochondrial membrane depolarization ratios were seen treated by compounds 2e, 2 h, and 2j. None of the analogs displayed any obvious inhibition activity on MMP-9. The physicochemical properties were predicted for all compounds and also molecular docking and dynamics simulation studies were realized for compound 2e, namely N-(6-methoxybenzothiazol-2-yl)-2-(4-(p-tolyl) piperazin-1-yl) acetamide. The results indicated that merging benzothiazole and piperazine derivatives via acetamide bridge is promising in cancer research because these moieties can interact with the loop and ss-sheet regions of MMP-9. So, 2e was considered as a potential therapeutic agent against lung carcinoma.