Potent hydrazone derivatives targeting esophageal cancer cells

Hydrazone and their derivatives are a series of highly active molecules, which are widely used as lead compounds for the research and development of new anti-cancer drugs. In this study, 20 compounds were synthesized, based on this scaffold and their in vitro cytotoxicity against 6 cancer cell lines, including EC9706, SMMC-7721, MCF7, PC3, MGC-803 and EC109 was tested. Among them, compound 6p, showed strong anti-proliferative activities on esophageal carcinoma cells: EC9706 and EC109 with IC₅₀ values of 1.09 ± 0.03 and 2.79 ± 0.45 μM, respectively. 6p also significantly induces both EC9706 and EC109 cell cycle arrest at G0/G1 phase and cell apoptosis, as well as intracellular ROS accumulation, which could be markedly reversed caspase or ROS inhibitor: NAC. Meanwhile, treatment of compound 6p results in significant declined mitochondria membrane potential, increases in the expression of P53 and bax, as well as decrease in Bcl-2. 6p also activates caspase-8/9/3, PARP and Bid, indicating that 6p induces cancer cell apoptosis via the death receptor-mediated extrinsic pathway and the mitochondria-mediated intrinsic pathway. Further studies also proved that 6p does not show obvious side effects at cellular and in vivo levels. Our findings suggested that hydrazone derivative: compound 6p may serve as a lead compound for further optimization against esophageal cancer cells.