PK11007 Covalently Inhibits Thioredoxin Reductase 1 to Induce Oxidative Stress and Autophagy Impairment in NSCLC Cells
Hanziyi Zhou1, Shibo Sun1, Haowen Liu1
1Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), School of Chemical Engineering, Ocean Technology and Life Science (CEOTLS) & Panjin Institute of Industrial Technology (PIIT), Dalian University of Technology, Panjin 124221, China.
Abstract:
Selenoprotein thioredoxin reductase 1 (TXNRD1) is frequently upregulated in various cancer cells to sustain cellular redox homeostasis, and its inhibition has emerged as a promising anti-cancer strategy. In this study, we identified PK11007, a thiol-modifying compound previously characterized as a p53 reactivator, as a potent inhibitor of TXNRD1. PK11007 irreversibly inhibited recombinant TXNRD1 in a time- and dose-dependent manner. Using differential scanning fluorimetry (DSF) and LC-MS/MS analysis, we confirmed that PK11007 covalently modifies the C-terminal redox motif (Cys497-Sec498) of TXNRD1. In non-small cell lung cancer (NSCLC) H1299 cells, PK11007-induced TXNRD1 inhibition disrupted cellular redox balance, leading to impaired autophagy flux and cell death. Similar autophagy suppression was observed in TXNRD1-knockdown cells, as well as pharmacological inhibition of TXNRD1 by Auranofin (AF) and TXNRD1 inhibitor 1 (TRi-1). Taken together, these findings highlight that oxidative stress contributes to the cytotoxic effects of PK11007 and uncover autophagy disorder as a downstream consequence of TXNRD1 inhibition.
Insights
PK11007, a p53 reactivator, was found to be a potent inhibitor of selenoprotein thioredoxin reductase 1 (TXNRD1). This inhibition disrupts cellular redox balance, leading to impaired autophagy and cell death in cancer cells.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Selenoprotein thioredoxin reductase 1 (TXNRD1) is upregulated in cancer, making its inhibition a potential anti-cancer strategy.
- TXNRD1 plays a crucial role in maintaining cellular redox homeostasis.
Purpose of the Study:
- To identify novel inhibitors of TXNRD1.
- To investigate the mechanism of action and downstream effects of TXNRD1 inhibition.
Main Methods:
- In vitro inhibition assays using recombinant TXNRD1.
- Differential scanning fluorimetry (DSF) and LC-MS/MS for covalent modification analysis.
- Cell-based assays in non-small cell lung cancer (NSCLC) H1299 cells to assess redox balance, autophagy, and cell death.
Main Results:
- PK11007 was identified as a potent, irreversible inhibitor of TXNRD1.
- PK11007 covalently modifies the C-terminal redox motif of TXNRD1.
- PK11007-induced TXNRD1 inhibition in NSCLC cells disrupted redox balance, impaired autophagy flux, and caused cell death.
- Autophagy suppression was also observed in TXNRD1-knockdown cells and cells treated with other TXNRD1 inhibitors (Auranofin, TRi-1).
Conclusions:
- PK11007 is a novel TXNRD1 inhibitor with anti-cancer potential.
- Oxidative stress induced by PK11007 contributes to its cytotoxic effects.
- Disruption of autophagy is a key downstream consequence of TXNRD1 inhibition by PK11007.
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