Preparation of Ergosterol Peroxide Prodrug Based on Glutathione Response and Evaluation of Its Antitumor Effect

Combining antitumor drugs with fluorescent groups to form therapeutic prodrugs has important application value in cancer treatment. In this study, we designed and synthesized a novel anticancer therapeutic prodrug, 2-(benzo[d]thiazol-2-yl)-4-methoxyphenyl 4-{[4-(ergosterol peroxide-3-yl-oxy)-4-oxobutyl]disulfaneyl}butanoate. The synthesis was achieved by covalently linking ergosterol peroxide (EP) and 2-(benzo[d]thiazol-2-yl)-4-methoxyphenol through a disulfide (S–S) bond. The reaction of the prodrug with high-concentration GSH in tumor tissues broke the disulfide bond, dissociating it into free EP and activated fluorescent BTMP, enabling the visual monitoring of the drug. A series of spectral analyses showed that 2-(benzo[d]thiazol-2-yl)-4-methoxyphenyl 4-{[4-(ergosterol peroxide-3-yl-oxy)-4-oxobutyl]disulfaneyl}butanoate could be specifically activated by high-concentration GSH and had good stability. Cytotoxicity assays showed that it had strong inhibitory activity against breast cancer MCF-7 cells but low toxicity toward human normal breast cells (MCF-10A). In addition, it could induce apoptosis and enable visual tracking in MCF-7 cells. Consequently, the specific drug-release behavior of 2-(benzo[d]thiazol-2-yl)-4-methoxyphenyl 4-{[4-(ergosterol peroxide-3-yl-oxy)-4-oxobutyl]disulfaneyl}butanoate within tumors renders it a highly promising prodrug candidate. This approach thus offers a viable strategy for tumor diagnosis and treatment.