Piperlongumine Inhibits Thioredoxin Reductase 1 by Targeting Selenocysteine Residues and Sensitizes Cancer Cells to Erastin
Yijia Yang,
Shibo Sun,
Weiping Xu,
Yue Zhang,
Rui Yang,
Kun Ma,
Jie Zhang,
Jianqiang Xu
Affiliations
Yijia Yang
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Shibo Sun
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Weiping Xu
School of Ocean Science and Technology (OST), Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), Dalian University of Technology, Panjin 124221, China
Yue Zhang
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Rui Yang
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Kun Ma
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Jie Zhang
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA
Jianqiang Xu
School of Life and Pharmaceutical Sciences (LPS), Panjin Institute of Industrial Technology (PIIT), Liaoning Key Laboratory of Chemical Additive Synthesis and Separation (CASS), Dalian University of Technology, Panjin 124221, China
Piperlongumine, a natural alkaloid substance extracted from the fruit of the long pepper (Piper longum Linn.), is known to inhibit the cytosolic thioredoxin reductase (TXNRD1 or TrxR1) and selectively kill cancer cells. However, the details and mechanism of the inhibition by piperlongumine against TXNRD1 remain unclear. In this study, based on the classical DTNB reducing assay, irreversible inhibition of recombinant TXNRD1 by piperlongumine was found and showed an apparent kinact value of 0.206 × 10−3 µM−1 min−1. Meanwhile, compared with the wild-type TXNRD1 (-GCUG), the UGA-truncated form (-GC) of TXNRD1 was resistant to piperlongumine, suggesting the preferential target of piperlongumine is the selenol (-SeH) at the C-terminal redox motif of the enzyme. Interestingly, the high concentration of piperlongumine-inhibited TXNRD1 showed that its Sec-dependent activity is decayed but its intrinsic NADPH oxidase activity is retained. Furthermore, piperlongumine did not induce ferroptosis in HCT116 cells at 10 µM, whereas significantly promoted erastin-induced lipid oxidation, which could be alleviated by supplying glutathione (GSH) or N-acetyl L-cysteine (NAC). However, restricting GSH synthesis by inhibiting glutaminase (GLS) using the small molecule inhibitor CB-839 only slightly enhanced erastin-induced cell death. Taken together, this study elucidates the molecular mechanism of the antitumor capacity of piperlongumine by targeting TXNRD1 and reveals the potential possibility of inhibiting TXNRD1 to strengthen cancer cells’ ferroptosis.
