bims-nurfca 2023-05-14 papers

Issue of 2023–05–14
five papers selected by
Caner Geyik, Istinye University

Inflammation. 2023 May 12.

Camptothecin Sensitizes Hepatocellular Carcinoma Cells to Sorafenib- Induced Ferroptosis Via Suppression of Nrf2.

Ahmed S Elkateb, Shahira Nofal, Sahar A Ali, Hanaa B Atya.

Sorafenib is a potent inducer of ferroptosis used to manage hepatocellular carcinoma (HCC). The ferroptosis induced by sorafenib activates the p62-Keap1-Nrf2 pathway. Abnormal activation of Nrf2 reduces sorafenib's efficiency and ferroptosis action and induces sorafenib's resistance. Consequently, our study tried to study the effect of a novel combination of sorafenib and Camptothecin (CPT, Nrf2 inhibitor) to improve sorafenib's ferroptosis action and reduce sorafenib resistance in the treatment of HCC. We evaluated the efficacy of sorafenib and/or CPT using HepG2 and Huh7 cell lines. MTT assay evaluated the anti-proliferation effects. The combination index (CI) and dose reduction index (DRI) were calculated using Isobologram analysis. Malondialdehyde (MDA), total antioxidant capacity (TAC), iron concentration, glutathione peroxidase (GPX4), and glutathione reductase (GR) activity assays were used to determine the ferroptosis action of drugs. Western blot was used to investigate the expression of the implicated proteins. Bioinformatics tools were used to determine the correlation between these proteins. Finally, the HPLC technique is used to measure cellular drug uptake. Our results revealed a strong synergism between sorafenib and CPT. The synergetic combination significantly increases lipid peroxidation and iron concentration, decreases TAC, GPX4 and GR activity, and reduces the expression of both Nrf2 and SLC7A11. The downregulation of Nrf2 expression has a vital role in the reduction of resistance mediators to sorafenib against HCC cells like (p62, MT1G, and ABCG2) and improves the cellular uptake of sorafenib. The current study provided evidence that Nrf2 inhibition by CPT improves sorafenib's sensitivity and reduces sorafenib's resistance via the augmentation of sorafenib's ferroptosis action.

Keywords: HCC.; Nrf2 inhibitor; ferroptosis; resistance; sorafenib

DOI: https://doi.org/10.1007/s10753-023-01823-4

Proc Natl Acad Sci U S A. 2023 05 16. 120(20): e2300763120

S-lactoyl modification of KEAP1 by a reactive glycolytic metabolite activates NRF2 signaling.

Yeonjin Ko, Mannkyu Hong, Seungbeom Lee, Manoj Kumar, Lara Ibrahim, Kayla Nutsch, Caroline Stanton, Phillip Sondermann, Braddock Sandoval, Maya L Bulos, Jonathan Iaconelli, Arnab K Chatterjee, R Luke Wiseman, Peter G Schultz, Michael J Bollong.

KEAP1 (Kelch-like ECH-associated protein), a cytoplasmic repressor of the oxidative stress responsive transcription factor Nuclear factor erythroid 2-related factor 2 (NRF2), senses the presence of electrophilic agents by modification of its sensor cysteine residues. In addition to xenobiotics, several reactive metabolites have been shown to covalently modify key cysteines on KEAP1, although the full repertoire of these molecules and their respective modifications remain undefined. Here, we report the discovery of sAKZ692, a small molecule identified by high-throughput screening that stimulates NRF2 transcriptional activity in cells by inhibiting the glycolytic enzyme pyruvate kinase. sAKZ692 treatment promotes the buildup of glyceraldehyde 3-phosphate, a metabolite which leads to S-lactate modification of cysteine sensor residues of KEAP1, resulting in NRF2-dependent transcription. This work identifies a posttranslational modification of cysteine derived from a reactive central carbon metabolite and helps further define the complex relationship between metabolism and the oxidative stress-sensing machinery of the cell.

Keywords: glycolysis; intrinsically reactive metabolite; posttranslational modification; pyruvate kinase

DOI: https://doi.org/10.1073/pnas.2300763120

J Biomol Struct Dyn. 2023 May 09. 1-26

Potential inhibitors of RPS6KB2 and NRF2 in head and neck squamous cell carcinoma.

Geet Madhukar, Naidu Subbarao.

Among the major altered pathways in head and neck squamous cell carcinoma, AKT/mTORC1/S6K and NRF2/KEAP1 pathway are quite significant. The overexpression and overstimulation of proteins from both these pathways makes them the promising candidates in cancer therapeutics. Inhibiting mTOR has been in research from past several decades but the tumour heterogeneity, and upregulation of several compensatory feed-back mechanisms, encourages to explore other downstream targets for inhibiting the pathway. One such downstream effectors of mTOR is S6K2. It is reported to be overexpressed in cancers such as head and neck cancer, breast cancer and prostate cancer. In case of NRF2/KEAP1 pathway, nuclear factor erythroid 2-related factor 2 (NFE2L2 or NRF2) is overexpressed in ∼90% of head and neck squamous cell carcinoma (HNSCC) cases. It associates with poor survival rate and therapeutic resistance in HNSCC treatment. NRF2 pathway is the primary antioxidant pathway in the cell which also serves pro-tumorigenic functions, such as repression of apoptosis, cell proliferation support and chemoresistance. The aim of this work was to explore S6K2 and NRF2 and identify novel and potential inhibitors against them for treating head and neck squamous cell carcinoma. Since the crystal structure of S6K2 was not available at the time of this study, we modelled its structure using homology modelling and performed high throughput screening, molecular dynamics simulations, free energy calculations and protein-ligand interaction studies to identify the inhibitors. We identified natural compounds Crocin and Gypenoside XVII against S6K2 and Chebulinic acid and Sennoside A against NRF2. This study provides a significant in-depth understanding of the two studied pathways and therefore can be used in the development of potential therapeutics against HNSCC.Communicated by Ramaswamy H. Sarma.

Keywords: AKT/mTORC1/S6K pathway; Chebulinic acid; Crocin; Gypenoside XVII; HNSCC; NFE2L2; NRF2; NRF2/KEAP1 pathway; RPS6KB2; S6K2; Sennoside A

DOI: https://doi.org/10.1080/07391102.2023.2205946

bioRxiv. 2023 Apr 28. pii: 2023.04.24.538118. [Epub ahead of print]

Metabolic Reprogramming by Histone Deacetylase Inhibition Selectively Targets NRF2-activated tumors.

Dimitris Karagiannis, Warren Wu, Albert Li, Makiko Hayashi, Xiao Chen, Michaela Yip, Vaibhav Mangipudy, Xinjing Xu, Francisco J Sánchez-Rivera, Yadira M Soto-Feliciano, Jiangbin Ye, Thales Papagiannakopoulos, Chao Lu.

Interplay between metabolism and chromatin signaling have been implicated in cancer initiation and progression. However, whether and how metabolic reprogramming in tumors generates specific epigenetic vulnerabilities remain unclear. Lung adenocarcinoma (LUAD) tumors frequently harbor mutations that cause aberrant activation of the NRF2 antioxidant pathway and drive aggressive and chemo-resistant disease. We performed a chromatin-focused CRISPR screen and report that NRF2 activation sensitized LUAD cells to genetic and chemical inhibition of class I histone deacetylases (HDAC). This association was consistently observed across cultured cells, syngeneic mouse models and patient-derived xenografts. HDAC inhibition causes widespread increases in histone H4 acetylation (H4ac) at intergenic regions, but also drives re-targeting of H4ac reader protein BRD4 away from promoters with high H4ac levels and transcriptional downregulation of corresponding genes. Integrative epigenomic, transcriptomic and metabolomic analysis demonstrates that these chromatin changes are associated with reduced flux into amino acid metabolism and de novo nucleotide synthesis pathways that are preferentially required for the survival of NRF2-active cancer cells. Together, our findings suggest that metabolic alterations such as NRF2 activation could serve as biomarkers for effective repurposing of HDAC inhibitors to treat solid tumors.

DOI: https://doi.org/10.1101/2023.04.24.538118

Biochem Biophys Res Commun. 2023 Apr 29. pii: S0006-291X(23)00548-X. [Epub ahead of print]665 178-186

Tripterygium glycosides reverse chemotherapy resistance in ovarian cancer by targeting the NRF2/GPX4 signal axis to induce ferroptosis of drug-resistant human epithelial ovarian cancer cells.

Bo Ma, Yanying Zhong, Runqiu Chen, Xinlu Zhan, Genhua Huang, Yifei Xiong, Buzhen Tan.

Cisplatin resistance is the main cause of postoperative recurrence and difficulty in the treatment of ovarian cancer. It is urgently needed to identify therapeutic drugs with unique functions to overcome the current challenges in the treatment of ovarian cancer. In this study, we found that TG promoted the accumulation of ROS and MDA in A2780/DDP cells and downregulated the expression of key antioxidant molecules. In vivo, the survival rate of tumor-bearing nude mice was prolonged by TG without significant hepatotoxic reaction. The expression of key antioxidant molecules in tumor tissues was consistent with that in vitro. These findings revealed that TG disrupted homeostasis of redox reactions and induced ferroptosis in A2780/DDP cells, thereby enhancing cisplatin chemosensitivity of ovarian cancer. Overall, TG may be a novel potential therapeutic option for reversing resistance to cisplatin chemotherapy.

Keywords: Ferroptosis; NRF2/GPX4 signal axis; Reversing resistance to cisplatin; Tripterygium glycosides

DOI: https://doi.org/10.1016/j.bbrc.2023.04.111