Design and Synthesis of Acridine-Triazole and Acridine-Thiadiazole Derivatives and Their Inhibitory Effect against Cancer Cells.

We report herein the design and synthesis of a series of novel acridine-triazole and acridine-thiadiazole derivatives. The newly synthesized compounds and the key intermediates were all evaluated for their antitumor activities against human foreskin fibroblasts (HFF), human gastric cancer cells-803 (MGC-803), hepatocellular carcinoma bel-7404 (BEL-7404), large cell lung cancer cells (NCI-H460), and bladder cancer cells (T24). Most of the compounds exhibited high levels of antitumor activity against MGC-803 and T24 but low toxicity against human normal liver cells (LO2), and their effect was even better than the commercial anticancer drugs, 5-fluorouracil (5-FU) and cis-platinum. Further, pharmacological mechanisms such as topo I, cell cycle, cell apoptosis, and neovascularization were all evaluated. Only a few compounds exhibited potent topo I inhibitory activity at 100 µM. In addition, the most active compounds with an IC50 value of 5.52-8.93 µM were chosen, and they could induce cell apoptosis in the G2 stage of MGC-803 or mainly arrest T24 cells in the S stage. To our delight, most of the compounds exhibited lower zebrafish cytotoxicity but could strongly inhibit the formation of zebrafish sub-intestinal veins, indicating a potential for clinical application.