In vivo tracking cystine/glutamate antiporter-mediated cysteine/cystine pool under ferroptosis.

Cysteine/cystine redox couple plays a vital role in maintaining the cellular redox state of living bio-systems. However, the dynamic changes of the intracellular cysteine/cystine pool mediated by cysteine/glutamate transporter (System X C −) in various cellular processes have remained incompletely understood. Here we established a series of strategies around fluorescent probe CP2 for effectively monitoring the intracellular cysteine level in living cells and in vivo zebrafish model, therefore for tracking dynamic changes of system X C −-mediated cysteine/cystine pool under ferroptosis. Living cell imaging and in vivo visualization both revealed that intracellular cysteine levels could be significantly reduced upon blocking system X C − activity and inducing ferroptotic cell death. This kind of blocking was potent against cisplatin-resistant A549R cancer cells, which might bring new potential for treating drug-resistant carcinoma through regulating system X C − and processes of ferroptosis. With further improvements in monitoring tools, understanding of system X C −-mediated cystine/cysteine pool and ferroptosis could certainly offer crucial information in more physiological or pathological processes. In this work, we established a series of strategies around fluorescent probe CP2 for effectively monitoring the intracellular cysteine level in living cells and zebrafish model, therefore for tracking dynamic changes of system X C −-mediated cysteine/cystine pool under ferroptosis. Living cell imaging and in vivo visualization both revealed that intracellular cysteine level could be significantly reduced upon treatment with system X C − inhibition and ferroptosis induction. This kind of blocking was potent against cisplatin-resistant A549R cancer cells, which might bring new potential for treating drug-resistant carcinoma through regulating system X C − and processes of ferroptosis. With monitoring tools further improved, further understanding of system X C −-mediated cystine/cysteine pool and ferroptosis could certainly offer crucial information in more physiological or pathological processes. Image 1 • New strategy for monitoring endogenous cysteine in cancer and dynamic changes of Cys/cystine pool in external stimulation. • Effectively monitoring intracellular cysteine in living cells and zebrafish thus tracking Cys/cystine changing. • The first report for imaging Cys/cystine pool dynamics during ferroptosis. • Revealing physiological or pathological role of the system XC--mediated Cys/cystine pool in ferroptosis> Providing possibility to circumvent drug resistance of cisplatin and identify inhibitors for ferroptosis-mediated therapy. [ABSTRACT FROM AUTHOR]