Ethaselen: a novel organoselenium anticancer agent targeting thioredoxin reductase 1 reverses cisplatin resistance in drug-resistant K562 cells by inducing apoptosis

Cysteine metabolism plays a critical role in cancer cell survival. Cysteine depletion was reported to inhibit tumor growth and induce pancreatic cancer cell ferroptosis. Nevertheless, the effect of cysteine depletion in chronic myeloid leukemia (CML) remains to be explored. In this work, we showed that cysteine depletion can induce K562/G01 but not K562 cell death in the form of ferroptosis. However, the glutathione (GSH)/glutathione peroxidase 4 (GPX4) pathways of the two CML cell lines were both blocked after cysteine depletion. This unexpected outcome guided us to perform RNA-Seq to screen the key genes that affect the sensitivity of CML cells to cysteine depletion. Excitingly, thioredoxin reductase 1 (TXNRD1), which related to cell redox metabolism, was significantly upregulated in K562/G01 cells after cysteine depletion. We further inferred that the upregulation is negatively feedback by the enzyme activity decrease of TXNRD1. Then, we triggered the ferroptosis by applying TXNRD1 shRNA and TXNRD1 inhibitor auranofin in K562 cells after cysteine depletion. In summary, we have reason to believe that TXNRD1 is a key regulator involved in the ferroptosis of CML cells induced by cysteine depletion in vitro. These findings highlight that cysteine depletion serves as a potential therapeutic strategy for overcoming chemotherapy resistance CML.

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UBE2L6 is Involved in Cisplatin Resistance by Regulating the Transcription of ABCB6

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200424130934 ◽

2020 ◽

Vol 20 (12) ◽

pp. 1487-1496 ◽

Cited By ~ 1

Author(s):

Midori Murakami ◽

Hiroto Izumi ◽

Tomoko Kurita ◽

Chiho Koi ◽

Yasuo Morimoto ◽

...

Keyword(s):

Gene Expression ◽

Promoter Activity ◽

Anticancer Agent ◽

Cisplatin Resistance ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Molecular Target ◽

Transcriptional Level ◽

And Control ◽

Resistant Cells

Background: Cisplatin is an important anticancer agent in cancer chemotherapy, but when resistant cells appear, treatment becomes difficult, and the prognosis is poor. Objective: In this study, we investigated the gene expression profile in cisplatin sensitive and resistant cells, and identified the genes involved in cisplatin resistance. Methods: Comparison of gene expression profiles revealed that UBE2L6 mRNA is highly expressed in resistant cells. To elucidate whether UBE2L6 is involved in the acquisition of cisplatin resistance, UBE2L6- overexpressing cells established from cisplatin-sensitive cells and UBE2L6-silenced cells developed from cisplatin- resistant cells were generated, and the sensitivity of cisplatin was examined. Results: The sensitivity of the UBE2L6-overexpressing cells did not change compared with the control cells, but the UBE2L6-silenced cells were sensitized to cisplatin. To elucidate the mechanism of UBE2L6 in cisplatin resistance, we compared the gene expression profiles of UBE2L6-silenced cells and control cells and found that the level of ABCB6 mRNA involved in cisplatin resistance was decreased. Moreover, ABCB6 promoter activity was partially suppressed in UBE2L6-silenced cells. Conclusion: These results suggest that cisplatin-resistant cells have upregulated UBE2L6 expression and contribute to cisplatin resistance by regulating ABCB6 expression at the transcriptional level. UBE2L6 might be a molecular target that overcomes cisplatin resistance.

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System-wide identification and prioritization of enzyme substrates by thermal analysis

Nature Communications ◽

10.1038/s41467-021-21540-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Amir Ata Saei ◽

Christian M. Beusch ◽

Pierre Sabatier ◽

Juan Astorga Wells ◽

Hassan Gharibi ◽

...

Keyword(s):

Thermal Analysis ◽

Thioredoxin Reductase ◽

Structural Level ◽

Post Translational Modification ◽

Post Translational Modifications ◽

Enzyme Substrate ◽

Thioredoxin Reductase 1 ◽

Enzyme Substrates ◽

Substrate Proteins

AbstractDespite the immense importance of enzyme–substrate reactions, there is a lack of general and unbiased tools for identifying and prioritizing substrate proteins that are modified by the enzyme on the structural level. Here we describe a high-throughput unbiased proteomics method called System-wide Identification and prioritization of Enzyme Substrates by Thermal Analysis (SIESTA). The approach assumes that the enzymatic post-translational modification of substrate proteins is likely to change their thermal stability. In our proof-of-concept studies, SIESTA successfully identifies several known and novel substrate candidates for selenoprotein thioredoxin reductase 1, protein kinase B (AKT1) and poly-(ADP-ribose) polymerase-10 systems. Wider application of SIESTA can enhance our understanding of the role of enzymes in homeostasis and disease, opening opportunities to investigate the effect of post-translational modifications on signal transduction and facilitate drug discovery.

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A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

Scientific Reports ◽

10.1038/s41598-021-92647-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yağmur Demircan Yalçın ◽

Taylan Berkin Töral ◽

Sertan Sukas ◽

Ender Yıldırım ◽

Özge Zorlu ◽

...

Keyword(s):

Drug Resistance ◽

K562 Cells ◽

Leukemia Cells ◽

Drug Resistant ◽

Wild Type ◽

Gene Expressions ◽

Before And After ◽

The Difference ◽

Selection Of ◽

Resistant Cells

AbstractWe report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance.

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Oxidative stress response in regulatory and conventional T cells: a comparison between patients with chronic coronary syndrome and healthy subjects

Journal of Translational Medicine ◽

10.1186/s12967-021-02906-2 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Anna K. Lundberg ◽

Rosanna W. S. Chung ◽

Louise Zeijlon ◽

Gustav Fernström ◽

Lena Jonasson

Keyword(s):

Oxidative Stress ◽

T Cells ◽

Mononuclear Cells ◽

Ex Vivo ◽

Thioredoxin Reductase ◽

Healthy Controls ◽

Antioxidant Genes ◽

Consistent Finding ◽

Coronary Syndrome ◽

Thioredoxin Reductase 1

Abstract Background Inflammation and oxidative stress form a vicious circle in atherosclerosis. Oxidative stress can have detrimental effects on T cells. A unique subset of CD4+ T cells, known as regulatory T (Treg) cells, has been associated with atheroprotective effects. Reduced numbers of Treg cells is a consistent finding in patients with chronic coronary syndrome (CCS). However, it is unclear to what extent these cells are sensitive to oxidative stress. In this pilot study, we tested the hypothesis that oxidative stress might be a potential contributor to the Treg cell deficit in CCS patients. Methods Thirty patients with CCS and 24 healthy controls were included. Treg (CD4+CD25+CD127−) and conventional T (CD4+CD25−, Tconv) cells were isolated and treated with increasing doses of H2O2. Intracellular ROS levels and cell death were measured after 2 and 18 h, respectively. The expression of antioxidant genes was measured in freshly isolated Treg and Tconv cells. Also, total antioxidant capacity (TAC) was measured in fresh peripheral blood mononuclear cells, and oxidized (ox) LDL/LDL ratios were determined in plasma. Results At all doses of H2O2, Treg cells accumulated more ROS and exhibited higher rates of death than their Tconv counterparts, p < 0.0001. Treg cells also expressed higher levels of antioxidant genes, including thioredoxin and thioredoxin reductase-1 (p < 0.0001), though without any differences between CCS patients and controls. Tconv cells from CCS patients were, on the other hand, more sensitive to oxidative stress ex vivo and expressed more thioredoxin reductase-1 than Tconv cells from controls, p < 0.05. Also, TAC levels were lower in patients, 0.97 vs 1.53 UAE/100 µg, p = 0.001, while oxLDL/LDL ratios were higher, 29 vs 22, p = 0.006. Conclusion Treg cells isolated from either CCS patients or healthy controls were all highly sensitive to oxidative stress ex vivo. There were signs of oxidant-antioxidant imbalance in CCS patients and we thus assume that oxidative stress may play a role in the reduction of Treg cells in vivo.

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