bims-nurfca Biomed News
on NRF2 and Cancer
Issue of 2023–01–22
eight papers selected by
Caner Geyik, Istinye University



  1. Eur J Pharmacol. 2023 Jan 12. pii: S0014-2999(23)00014-6. [Epub ahead of print]941 175503
      Cervical and endometrial cancers are among the most dangerous gynaecological malignancies, with high fatality and recurrence rates due to frequent diagnosis at an advanced stage and chemoresistance onset. The NRF2/KEAP1 signalling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. NRF2, activated by ROS, induces the expression of antioxidant enzymes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase which neutralize ROS, protecting cells against oxidative stress damage. However, activation of NRF2/KEAP1 signalling in cancer cells results in chemoresistance, inactivating drug-mediated oxidative stress and protecting cancer cells from drug-induced cell death. We review the literature on the role of the NRF2/KEAP1 pathway in cervical and endometrial cancers, with a focus on the expression of its components and downstream genes. We also examine the role of the NRF2/KEAP1 pathway in chemotherapy resistance and how this pathway can be modulated by natural and synthetic modulators.
    Keywords:  Cervical cancer; Chemotherapy; Cisplatin; Endometrial cancer; Nrf2; Oxidative stress
    DOI:  https://doi.org/10.1016/j.ejphar.2023.175503
  2. Cancer Res. 2023 Jan 19. pii: CAN-22-1903. [Epub ahead of print]
      Radiotherapy is one of the primary treatments of head and neck squamous cell carcinoma (HNSCC), which has a high risk of locoregional failure (LRF). Presently, there is no reliable predictive biomarker of radioresistance in HNSCC. Here, we found that mutations in NFE2L2, which encodes Nrf2, are associated with a significantly higher rate of LRF in patients with oral cavity cancer treated with surgery and adjuvant (chemo)radiotherapy but not in those treated with surgery alone. Somatic mutation of NFE2L2 led to Nrf2 activation and radioresistance in HNSCC cells. Tumors harboring mutant Nrf2E79Q were substantially more radioresistant than tumors with wild-type Nrf2 in immunocompetent mice, while the difference was diminished in immunocompromised mice. Nrf2E79Q enhanced radioresistance through increased recruitment of intratumoral polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and reduction of M1-polarized macrophages. Treatment with the glutaminase inhibitor CB-839 overcame the radioresistance induced by Nrf2E79Q or Nrf2E79K. Radiotherapy increased expression of PMN-MDSC-attracting chemokines, including CXCL1, CXLC3 and CSF3, in Nrf2E79Q-expressing tumors via the TLR4, which could be reversed by CB-839. This study provides insights into the impact of NFE2L2 mutations on radioresistance and suggests that CB-839 can increase radiosensitivity by switching intratumoral myeloid cells to an anti-tumor phenotype, supporting clinical testing of CB-839 with radiation in HNSCC with NFE2L2 mutations.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-22-1903
  3. Antioxidants (Basel). 2023 Jan 03. pii: 116. [Epub ahead of print]12(1):
      The NRF2/KEAP1 pathway protects healthy cells from malignant transformation and maintains cellular homeostasis. Up to 30% of human lung tumors gain constitutive NRF2 activity which contributes to cancer cell survival and chemoresistance, but the effects of NRF2 activation in immune cells within the tumor microenvironment are underexplored. Macrophages can promote cancer progression or regression depending on context, and NRF2 activation affects macrophage activity. The NRF2 activator CDDO-Methyl ester (CDDO-Me or bardoxolone methyl) reprogrammed Nrf2 wild-type (WT) tumor-educated bone marrow-derived macrophages (TE-BMDMs) from a tumor-promoting to a tumor-inhibiting phenotype, marked by an increase in M1 markers TNFα, IL-6, and MHC-II and a decrease in the tumor-promoting factors VEGF, CCL2, and CD206. No changes were observed in Nrf2 knockout (KO) TE-BMDMs. CDDO-Me decreased tumor burden (p < 0.001) and improved pathological grade (p < 0.05) in WT but not Nrf2 KO A/J mice. Tumor burden in Nrf2 KO mice was 4.6-fold higher (p < 0.001) than in WT mice, irrespective of treatment. CDDO-Me increased the number of lung-infiltrating macrophages in WT mice but lowered CD206 expression in these cells (p < 0.0001). In summary, Nrf2 KO exacerbates lung tumorigenesis in A/J mice, and CDDO-Me promotes an Nrf2-dependent, anti-cancer macrophage phenotype.
    Keywords:  CDDO-Methyl ester; Keap1; Nrf2; Nrf2 regulators; bardoxolone methyl; lung cancer; macrophages; tumor microenvironment
    DOI:  https://doi.org/10.3390/antiox12010116
  4. J Oncol. 2023 ;2023 4211885
       Background: Esophageal cancer (EC) had the sixth-highest mortality rate of all cancers due to its poor prognosis. Immune cells and mutation genes influenced the prognosis of EC, but their combined effect on predicting EC prognosis was unknown. In this study, we comprehensively analyzed the immune cell infiltration (ICI) and mutation genes and their combined effects for predicting prognosis in EC.
    Methods: The CIBERSORT and ESTIMATE algorithms were used to analyse the ICI scape based on the TCGA and GEO databases. EC tissues and pathologic sections from Huai'an, China, were used to verify the key immune cells and mutation genes and their interactions.
    Results: Stromal/immune score patterns and ICI/gene had no statistical significance in overall survival (OS) (p > 0.05). The combination of ICI and tumor mutation burden (TMB) showed that the high TMB and high ICI score group had the shortest OS (p = 0.004). We recognized that the key mutation gene NRF2 was significantly different in the high/low ICI score subgroups (p = 0.002) and positivity with mast cells (MCs) (p < 0.05). Through experimental validation, we found that the MCs and activated mast cells (AC-MCs) were more infiltration in stage II/III (p = 0.032; p = 0.013) of EC patients and that NRF2 expression was upregulated in EC (p = 0.045). AC-MCs combined with NRF2 had a poor prognosis, according to survival analysis (p = 0.056) and interactive analysis (p = 0.032).
    Conclusions: We presume that NRF2 combined with AC-MCs could be a marker to predict prognosis and could influence immunotherapy through regulating PD-L1 in the EC.
    DOI:  https://doi.org/10.1155/2023/4211885
  5. Int J Biochem Cell Biol. 2023 Jan 11. pii: S1357-2725(23)00002-X. [Epub ahead of print]156 106363
      Hepatocellular carcinoma (HCC) is characterized by a poor prognosis. Our previous work suggested that Protocadherin 20 (PCDH20) promoted ferroptosis in HCC. Nevertheless, the underlying mechanism remains elusive. Recently, we found that both the mRNA and protein levels of PCDH20 were upregulated in erastin- or sorafenib-treated HCC cells. Meanwhile, data showed that Sirtuin 1 (SIRT1) was markedly downregulated in PCDH20-SNU-449 cells. Additionally, overexpression of PCDH20 or erastin-treated cells dramatically decreased cell viability and colony-forming capacity of HCC cells, whereas blocking PCDH20 reversed these effects. Moreover, PCDH20 overexpression or treatment with erastin significantly downregulated the expression of SIRT1, Solute carrier family 7 member 11 (SLC7A11), as well as the ferroptosis-related protein glutathione peroxidase 4 (GPX4) and glutathione (GSH), while elevated malondialdehyde (MDA), 2'- 7'-dichlorofluorescein (DCF) and intercellular iron levels. Conversely, knockdown of PCDH20 upregulated SIRT1 and SLC7A11. Immunoprecipitation assay demonstrated that PCDH20 or erastin increased the amount of acetylated nuclear factor erythroid 2-related factor-2 (NRF2). This reducing effect of NRF2 deacetylation by PCDH20 was counteracted by restoring the expression of SIRT1. In addition, PCDH20 lowered the levels of GPX4, GSH, and cell viability, as well as resulted in an elevation in intercellular iron level, MDA, and DCF. These effects were reversed by SIRT1 expression. Besides, PCDH20 could promote ferroptosis by inhibiting SIRT1 from deacetylating NRF2, which led to the downregulation of SLC7A11, GPX4, and GSH both in vivo and in vitro. Our results signals that PCDH20 promotes ferroptosis by suppressing the expression of SIRT1 and thus, promoting the acetylation of NRF2in HCC.
    Keywords:  Ferroptosis; Hepatocellular carcinoma; NRF2; PCDH20; SIRT1
    DOI:  https://doi.org/10.1016/j.biocel.2023.106363
  6. Gene. 2023 Jan 11. pii: S0378-1119(23)00035-5. [Epub ahead of print] 147194
      Esophageal squamous cell carcinoma (ESCC) pathogenesis is influenced by both NFE2L2 (nuclear factor erythroid 2-related factor 2) and SQSTM1 (sequestosome 1), also known as p62. However, while there is evidence that these two proteins can interact with one another in a range of pathological contexts, whether these interactions govern the development or progression of ESCC remains unknown. In the present study, analyses of the GEPIA database revealed the simultaneous upregulation of both NFE2L2 and p62 in ESCC, as was further confirmed through biochemical analyses conducted with a human tumor microarray. Knocking down the expression of one or both of these factors demonstrated that both p62 and NFE2L2 mediate the progression of ESCC, as such downregulation altered the morphological characteristics of these cells and suppressed the epithelial-mesenchymal transition (EMT). Strikingly, these experiments revealed synergistic interactions between NFE2L2 and p62 in the promotion of ESCC invasivity and EMT induction. The treatment of cells with the autophagy inhibitors 3-MA, however, was sufficient to partially reverse the anti-metastatic effects of knocking down p62 and/or NFE2L2. Together, these data illustrate the ability of p62 and NFE2L2 to function in a synergistic manner, promoting ESCC cell metastatic progression and EMT induction through mechanisms linked to autophagic activity. As such, efforts to simultaneously target both of these proteins may represent a viable means of providing new treatment options to ESCC patients.
    Keywords:  EMT; ESCC; NFE2L2; autophagy; metastasis; p62
    DOI:  https://doi.org/10.1016/j.gene.2023.147194
  7. Free Radic Biol Med. 2023 Jan 13. pii: S0891-5849(23)00005-9. [Epub ahead of print]196 65-80
      Although the advent of osimertinib has brought revolutionary changes to the treatment landscape of non-small cell lung cancer (NSCLC) patients, acquired resistance remains a major obstacle limiting long-term survival benefits for the treatment of cancer. The purpose of this study was to examine the mechanisms involved in the ability of bazedoxifene to synergistically enhance osimertinib sensitivity, which will aid in delaying and overcoming osimertinib resistance to improve patient outcomes. Here, we found that osimertinib increased the production of reactive oxygen species (ROS), promoted mitochondrial fission, diminished mitochondrial membrane potential, and activated cell apoptosis. Moreover, the p-STAT3/suppressor of cytokine signaling 3 (SOCS3) and KEAP1/NRF2 signaling pathways were activated to scavenge ROS and promote osimertinib resistance. Mechanistically, SOCS3 can directly bind to KEAP1 to prevent the degradation of NRF2, resulting in the activation of an NRF2-dependent transcriptional program. Furthermore, the osimertinib-induced mitochondrial dysfunction and apoptosis were enhanced by bazedoxifene, thereby delaying and overcoming osimertinib resistance by inhibiting these pathways in vitro and in vivo. These findings identified a new critical link in the p-STAT3/SOCS3 pathway, KEAP1/NRF2 pathway, mitochondrial dysfunction, and osimertinib resistance. The present study demonstrated that bazedoxifene can be used for delaying or overcoming osimertinib resistance in NSCLC.
    Keywords:  Bazedoxifene; Mitochondrial dysfunction; NSCLC; Osimertinib resistance
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2023.01.004
  8. Phytomedicine. 2023 Jan 15. pii: S0944-7113(23)00028-4. [Epub ahead of print]111 154668
       BACKGROUND: Combination therapy with other antineoplastic agent is a favorable approach for targeting the molecules involved in sorafenib resistance.
    PURPOSE: In the present study, we determined whether tiliroside, a natural flavonoid glycoside isolated from oriental paperbush flower, could improve the sensitivity of hepatocellular carcinoma (HCC) cells to sorafenib. Furthermore, we investigated the mechanisms and identified the potential drug targets of tiliroside.
    METHODS: Synergy was performed using CalcuSyn. Transcriptomic studies were adopted to investigate whether tiliroside could induce ferroptosis and inhibit the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in HCC cells. Ferroptosis was analyzed using western blotting, flow cytometry, and transmission electron microscopy. Immunofluorescence, co-immunoprecipitation, and Nrf2 knockdown or overexpression were performed to confirm the involvement of Nrf2 in tiliroside-induced ferroptosis. Additionally, molecular docking and biolayer interferometry-based measurements were used to confirm the direct target of tiliroside. Finally, subcutaneous xenograft and orthotopic xenograft tumors in nude mice were used to assess the effects of tiliroside in vivo.
    RESULTS: Tiliroside significantly enhanced the anti-HCC activity of sorafenib without any discernible side effects. Moreover, the combination of tiliroside and sorafenib induced synergistic effects against HCC in vitro. The inhibitory effects of tiliroside on HCC were antagonized by N-acetylcysteine and the ferroptosis inhibitor liproxstatin-1. Studies on the mechanism of action revealed that tiliroside could directly bind to TANK-binding kinase 1 (TBK1) and inhibit its enzymatic activity. Inhibition of TBK1 by tiliroside decreased the phosphorylation of serine 349 on sequestosome-1 (p62) and the affinity of p62 for kelch like ECH-associated protein 1 (Keap1) and promoted Keap1-mediated Nrf2 ubiquitination and degradation. The downstream target proteins of Nrf2, including glutathione peroxidase 4, ferritin heavy chain 1, and glucose-6-phosphate dehydrogenase, demonstrated similar results to that of Nrf2 protein, inducing ferroptosis in tiliroside-treated HCC cells. We extended these findings in vivo and found that tiliroside inhibited the growth of HepG2 tumors in both subcutaneous xenograft and orthotopic xenograft tumor models of HCC.
    CONCLUSION: Our findings imply that tiliroside is a potent TBK1 inhibitor and a candidate natural anti-cancer product that could function as a sensitizer of sorafenib in HCC treatment by targeting TBK1 to induce ferroptosis.
    Keywords:  Ferroptosis; Hepatocellular carcinoma; Sorafenib resistance; TANK-binding kinase 1; Tiliroside
    DOI:  https://doi.org/10.1016/j.phymed.2023.154668