A highly selective fluorescent probe for detecting glutathione transferases to reveal anticancer-activity sensitivity of cisplatin in cancer cells and tumor tissues

Cisplatin is a widely used anti-cancer drug in clinic, while many cancer cells gradually exhibited serious cisplatin resistance recently, which resulted in reducing its clinical effects. Glutathione transferases (GSTs) as an extensive expressed metabolic enzyme in human, plays a significant role in the metabolism of cisplatin. Thus, sensitively and accurately detecting the activity of GSTs in various cancer cells and tumor tissues is very urgent for the rational use of cisplatin in clinic. Herein, a fluorescent probe (BDCN) for GSTs detection was developed, with the high selectivity, prominent sensitivity and an ultrahigh imaging resolution, importantly, this detection progress was not affected by the interference of endogenous and exogenous substances especially GSH. The activity of GSTs in MCF-7, LoVo cells and even tumor tissues was successfully analyzed and imaged by BDCN. Notably, MCF-7 cells displayed a much higher expression of GSTs than LoVo cells, which was also confirmed by western bolt. The significant differences of GSTs expression directly resulted in the stronger resistance of MCF-7 cells toward cisplatin than LoVo cells and inhibiting the expression of GSTs with siRNA, further decreasing MCF-7 cells resistance toward cisplatin. These findings demonstrated that GSTs contributed to the intrinsic resistance of cancer cells toward cisplatin. Importantly, BDCN may serve as a promising tool for studying the biological function and process of cellular GSTs in living systems and further provide vital guidance in cancer treatment by cisplatin.