Developing a binuclear multi-target Bi(III) complex by optimizing 2-acetyl-3-ethylpyrazine thiosemicarbazides

On the one hand, the multi-target agents have been promising for overcoming the deficiency of the single targeted anticancer metal agents, on the other hand, bismuth (Bi) complexes have shown significant antiproliferative activity and minimal side effects. Therefore, to develop the next-generation anticancer metal agents, we designed and synthesized four novel binuclear Bi(III) complexes by modifying the N-4 position of a series of 2-Acetyl-3-ethylpyrazine thiosemicarbazides, and then investigated their structure-activity relationships to human cancer cell lines, obtaining a lead Bi drug (C4) with significant antiproliferative activity to human bladder cancer cells (T24). C4 arrested the cell cycle in the S-phase by regulation of cyclin and cyclin-dependent kinases, and exerted a chemotherapeutic effect via multi-target mechanism including the activation of apoptotic and autophagic cell signaling pathways. Besides, C4 effectively inhibited metastasis of T24 cell. Our results suggested that C4 can be developed as a potential multi-target anticancer candidate.