bims-nurfca Biomed News
on NRF2 and Cancer
Issue of 2023‒05‒21
ten papers selected by
Caner Geyik
Istinye University


  1. Biomedicines. 2023 Apr 03. pii: 1081. [Epub ahead of print]11(4):
      The transcription factor NRF2 is constitutively active in glioblastoma, a highly aggressive brain tumor subtype with poor prognosis. Temozolomide (TMZ) is the primary chemotherapeutic agent for this type of tumor treatment, but resistance to this drug is often observed. This review highlights the research that is demonstrating how NRF2 hyperactivation creates an environment that favors the survival of malignant cells and protects against oxidative stress and TMZ. Mechanistically, NRF2 increases drug detoxification, autophagy, DNA repair, and decreases drug accumulation and apoptotic signaling. Our review also presents potential strategies for targeting NRF2 as an adjuvant therapy to overcome TMZ chemoresistance in glioblastoma. Specific molecular pathways, including MAPKs, GSK3β, βTRCP, PI3K, AKT, and GBP, that modulate NRF2 expression leading to TMZ resistance are discussed, along with the importance of identifying NRF2 modulators to reverse TMZ resistance and develop new therapeutic targets. Despite the significant progress in understanding the role of NRF2 in GBM, there are still unanswered questions regarding its regulation and downstream effects. Future research should focus on elucidating the precise mechanisms by which NRF2 mediates resistance to TMZ, and identifying potential novel targets for therapeutic intervention.
    Keywords:  NRF2; glioblastoma; temozolomide
    DOI:  https://doi.org/10.3390/biomedicines11041081
  2. Oncogene. 2023 May 15.
      Resistance to temozolomide (TMZ) remains an important cause of treatment failure in patients with glioblastoma multiforme (GBM). TRIM25, as a tripartite motif-containing (TRIM) family member, plays a significant role in cancer progression and chemoresistance. However, the function of TRIM25 and its precise mechanism in regulating GBM progression and TMZ resistance remain poorly understood. We found that the expression of TRIM25 was upregulated in GBM, and it was associated with tumor grade and TMZ resistance. Elevated TRIM25 expression predicted a poor prognosis in GBM patients and enhanced tumor growth in vitro and in vivo. Further analysis revealed that elevated TRIM25 expression inhibited oxidative stress and ferroptotic cell death in glioma cells under TMZ treatment. Mechanistically, TRIM25 regulates TMZ resistance by promoting the nuclear import of nuclear factor erythroid 2-related factor 2(Nrf2) via keap1 ubiquitination. Knockdown of Nrf2 abolished the ability of TRIM25 to promote glioma cell survival and TMZ resistance. Our results support the targeting of TRIM25 as a new therapeutic strategy for glioma.
    DOI:  https://doi.org/10.1038/s41388-023-02717-3
  3. Exp Hematol Oncol. 2023 May 17. 12(1): 47
      Drug resistance and poor treatment response are major obstacles to the effective treatment of acute myeloid leukemia (AML). A deeper understanding of the mechanisms regulating drug resistance and response genes in AML is therefore urgently needed. Our previous research has highlighted the important role of nuclear factor E2-related factor 2 (NRF2) in AML, where it plays a critical role in detoxifying reactive oxygen species and influencing sensitivity to chemotherapy. In this study, we identify a core set of direct NRF2 targets that are involved in ferroptosis, a novel form of cell death. Of particular interest, we find that glutathione peroxidase 4 (GPX4) is a key ferroptosis gene that is consistently upregulated in AML, and high expression of GPX4 is associated with poor prognosis for AML patients. Importantly, simultaneous inhibition of NRF2 with ML385 and GPX4 with FIN56 or RSL3 synergistically targets AML cells, triggering ferroptosis. Treatment with ML385 + FIN56/RSL3 resulted in a marked reduction in NRF2 and GPX4 expression. Furthermore, NRF2 knockdown enhanced the sensitivity of AML cells to the ferroptosis inducers. Taken together, our results suggest that combination therapy targeting both NRF2 and GPX4 may represent a promising approach for the treatment of AML.
    Keywords:  Acute myeloid leukemia; Ferroptosis; GPX4; NRF2
    DOI:  https://doi.org/10.1186/s40164-023-00411-4
  4. Free Radic Biol Med. 2023 May 11. pii: S0891-5849(23)00407-0. [Epub ahead of print]
      The redox sensitive transcription factor NRF2 is a central regulator of the transcriptional response to reactive oxygen species (ROS). NRF2 is widely recognized for its ROS-responsive upregulation of antioxidant genes that are essential for mitigating the damaging effects of oxidative stress. However, multiple genome-wide approaches have suggested that NRF2's regulatory reach extends well beyond the canonical antioxidant genes, with the potential to regulate many noncanonical target genes. Recent work from our lab and others suggests HIF1A, which encodes the hypoxia-responsive transcription factor HIF1α, is one such noncanonical NRF2 target. These studies found that NRF2 activity is associated with high HIF1A expression in multiple cellular contexts, HIF1A expression is partially dependent on NRF2, and there is a putative NRF2 binding site (antioxidant response element, or ARE) approximately 30 kilobases upstream of HIF1A. These findings all support a model in which HIF1A is a direct target of NRF2, but did not confirm the functional importance of the upstream ARE in HIF1A expression. Here we use CRISPR/Cas9 genome editing to mutate this ARE in its genomic context and test the impact on HIF1A expression. We find that mutation of this ARE in a breast cancer cell line (MDA-MB-231) eliminates NRF2 binding and decreases HIF1A expression at the transcript and protein levels, and disrupts HIF1α target genes as well as phenotypes driven by these HIF1α targets. Taken together, these results indicate that this NRF2 targeted upstream ARE plays an important role in the expression of HIF1A and activity of the HIF1α axis in MDA-MB-231 cells.
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2023.05.003
  5. Int J Mol Sci. 2023 May 05. pii: 8265. [Epub ahead of print]24(9):
      Triple-negative breast cancer (TNBC) has been clearly recognized as a heterogeneous tumor with the worst prognosis among the subtypes of breast cancer (BC). The advent and application of current small-molecule drugs for treating TNBC, as well as other novel inhibitors, among others, have made treatment options for TNBC more selective. However, there are still problems, such as poor patient tolerance, large administration doses, high dosing frequency, and toxic side effects, necessitating the development of more efficient and less toxic treatment strategies. High expression of Nrf2, a vital antioxidant transcription factor, often promotes tumor progression, and it is also one of the most effective targets in BC therapy. We found that in MDA-MB-231 cells and SUM159 cells, brusatol (BRU) combined with polydatin (PD) could significantly inhibit cell proliferation in vitro, significantly downregulate the expression of Nrf2 protein as well as the expression of downstream related target genes Heme Oxygenase-1 (HO-1) and NAD(P)H dehydrogenase, quinone 1 (NQO1), and promote reactive oxygen species (ROS) levels to further strengthen the anti-tumor effect. Furthermore, we discovered in our in vivo experiments that by reducing the drug dosage three times, we could significantly reduce tumor cell growth while avoiding toxic side effects, providing a treatment method with greater clinical application value for TNBC treatment.
    Keywords:  HO-1; NQO1; Nrf2; ROS; breast cancer; brusatol; polydatin
    DOI:  https://doi.org/10.3390/ijms24098265
  6. J Exp Clin Cancer Res. 2023 May 19. 42(1): 127
      BACKGROUND: Ferroptosis has been linked to tumor progression and resistance to antineoplastic therapy. Long noncoding RNA (lncRNA) exerts a regulatory role in various biological processes of tumor cells, while the function and molecular mechanism of lncRNA in ferroptosis are yet to be clarified in glioma.METHODS: Both gain-of-function and loss-of-function experiments were employed to investigate the effects of SNAI3-AS1 on the tumorigenesis and ferroptosis susceptibility of glioma in vitro and in vivo. Bioinformatics analysis, Bisulfite sequencing PCR, RNA pull-down, RIP, MeRIP and dual-luciferase reporter assay were performed to explore the low expression mechanism of SNAI3-AS1 and the downstream mechanism of SNAI3-AS1 in ferroptosis susceptibility of glioma.
    RESULTS: We found that ferroptosis inducer erastin downregulates SNAI3-AS1 expression in glioma by increasing the DNA methylation level of SNAI3-AS1 promoter. SNAI3-AS1 functions as a tumor suppressor in glioma. Importantly, SNAI3-AS1 enhances the anti-tumor activity of erastin by promoting ferroptosis both in vitro and in vivo. Mechanistically, SNAI3-AS1 competitively binds to SND1 and perturbs the m6A-dependent recognition of Nrf2 mRNA 3'UTR by SND1, thereby reducing the mRNA stability of Nrf2. Rescue experiments confirmed that SND1 overexpression and silence can rescue the gain- and loss-of-function ferroptotic phenotypes of SNAI3-AS1, respectively.
    CONCLUSIONS: Our findings elucidate the effect and detailed mechanism of SNAI3-AS1/SND1/Nrf2 signalling axis in ferroptosis, and provide a theoretical support for inducing ferroptosis to improve glioma treatment.
    Keywords:  Ferroptosis; Glioma; LncRNA; Nrf2; m6A
    DOI:  https://doi.org/10.1186/s13046-023-02684-3
  7. Int J Mol Sci. 2023 Apr 22. pii: 7706. [Epub ahead of print]24(9):
      Glioblastoma multiforme (GBM) is a highly heterogeneous disease with a mesenchymal subtype tending to exhibit more aggressive and multitherapy-resistant features. Glioblastoma stem-cells derived from mesenchymal cells are reliant on iron supply, accumulated with high reactive oxygen species (ROS), and susceptible to ferroptosis. Temozolomide (TMZ) treatment is the mainstay drug for GBM despite the rapid development of resistance in mesenchymal GBM. The main interconnection between mesenchymal features, TMZ resistance, and ferroptosis are poorly understood. Herein, we demonstrated that a subunit of NADPH oxidase, CYBB, orchestrated mesenchymal shift and promoted TMZ resistance by modulating the anti-ferroptosis circuitry Nrf2/SOD2 axis. Public transcriptomic data re-analysis found that CYBB and SOD2 were highly upregulated in the mesenchymal subtype of GBM. Accordingly, our GBM cohort confirmed a high expression of CYBB in the GBM tumor and was associated with mesenchymal features and poor clinical outcome. An in vitro study demonstrated that TMZ-resistant GBM cells displayed mesenchymal and stemness features while remaining resilient to erastin-mediated ferroptosis by activating the CYBB/Nrf2/SOD2 axis. The CYBB maintained a high ROS state to sustain the mesenchymal phenotype, TMZ resistance, and reduced erastin sensitivity. Mechanistically, CYBB interacted with Nrf2 and consequently regulated SOD2 transcription. Compensatory antioxidant SOD2 essentially protected against the deleterious effect of high ROS while attenuating ferroptosis in TMZ-resistant cells. An animal study highlighted the protective role of SOD2 to mitigate erastin-triggered ferroptosis and tolerate oxidative stress burden in mice harboring TMZ-resistant GBM cell xenografts. Therefore, CYBB captured ferroptosis resilience in mesenchymal GBM. The downstream compensatory activity of CYBB via the Nrf2/SOD2 axis is exploitable through erastin-induced ferroptosis to overcome TMZ resistance.
    Keywords:  CYBB; SOD2; erastin; ferroptosis; glioblastoma; mesenchymal; temozolomide
    DOI:  https://doi.org/10.3390/ijms24097706
  8. Biomedicines. 2023 Mar 24. pii: 1010. [Epub ahead of print]11(4):
      Renal-cell carcinoma (RCC) is a heterogeneous disease consisting of several subtypes based on specific genomic profiles and histological and clinical characteristics. The subtype with the highest prevalence is clear-cell RCC (ccRCC), next is papillary RCC (pRCC), and then chromophobe RCC (chRCC). The ccRCC cell lines are further subdivided into prognostic expression-based subtypes ccA or ccB. This heterogeneity necessitates the development, availability, and utilization of cell line models with the correct disease phenotypic characteristics for RCC research. In this study, we focused on characterizing proteomic differences between the Caki-1 and Caki-2 cell lines that are commonly used in ccRCC research. Both cells are primarily defined as human ccRCC cell lines. Caki-1 cell lines are metastatic, harboring wild-type VHL, whereas Caki-2 are considered as the primary ccRCC cell lines expressing wild-type von Hippel-Lindau protein (pVHL). Here, we performed a comprehensive comparative proteomic analysis of Caki-1 and Caki-2 cells using tandem mass-tag reagents together with liquid chromatography mass spectrometry (LC/MS) for the identification and quantitation of proteins in the two cell lines. Differential regulation of a subset of the proteins identified was validated using orthogonal methods including western blot, q-PCR, and immunofluorescence assays. Integrative bioinformatic analysis identifies the activation/inhibition of specific molecular pathways, upstream regulators, and causal networks that are uniquely regulated and associated with the two cell lines and RCC subtypes, and potentially the disease stage. Altogether, we have identified multiple molecular pathways, including NRF2 signaling, which is the most significantly activated pathway in Caki-2 versus Caki-1 cells. Some of the differentially regulated molecules and signaling pathways could serve as potential diagnostic and prognostic biomarkers and therapeutic targets amongst ccRCC subtypes.
    Keywords:  clear-cell renal-cell carcinoma; renal-cell carcinoma; signaling pathway activation
    DOI:  https://doi.org/10.3390/biomedicines11041010
  9. Cell Death Differ. 2023 May 12.
      The ubiquitin-proteasome system governs a wide spectrum of cellular events and offers therapeutic opportunities for pharmacological intervention in cancer treatment. Renal clear cell carcinoma represents the predominant histological subtype and accounts for the majority of cancer death related to kidney malignancies. Through a systematic survey in the association of human ubiquitin-specific proteases with patient prognosis of renal clear cell carcinoma and subsequent phenotypic validation, we uncovered the tumor-promoting role of USP35. Biochemical characterizations confirmed the stabilizing effects of USP35 towards multiple members of the IAP family in an enzymatic activity-dependent manner. USP35 silencing led to reduced expression levels of IAP proteins, which were accompanied with increased cellular apoptosis. Further transcriptomic analysis revealed that USP35 knockdown affected the expression levels of NRF2 downstream transcripts, which were conferred by compromised NRF2 abundance. USP35 functions to maintain NRF2 levels by catalyzing its deubiquitylation and thus antagonizing degradation. NRF2 reduction imposed by USP35 silencing rendered renal clear cell carcinoma cells increased sensitivity to ferroptosis induction. Finally, induced USP35 knockdown markedly attenuated xenograft formation of renal clear cell carcinoma in nude mice. Hence, our findings reveal a number of USP35 substrates and uncover the protecting roles of USP35 against both apoptosis and ferroptosis in renal clear cell carcinoma.
    DOI:  https://doi.org/10.1038/s41418-023-01176-3
  10. Sci Rep. 2023 May 15. 13(1): 7869
      PARP2 is a member of the PARP enzyme family. Although, PARP2 plays role in DNA repair, it has regulatory roles in mitochondrial and lipid metabolism, it has pivotal role in bringing about the adverse effects of pharmacological PARP inhibitors. Previously, we showed that the ablation of PARP2 induces oxidative stress and, consequently, mitochondrial fragmentation. In attempt to identify the source of the reactive species we assessed the possible role of a central regulator of cellular antioxidant defense, nuclear factor erythroid 2-related factor 2 (NRF2). The silencing of PARP2 did not alter either the mRNA or the protein expression of NRF2, but changed its subcellular localization, decreasing the proportion of nuclear, active fraction of NRF2. Pharmacological inhibition of PARP2 partially restored the normal localization pattern of NRF2 and in line with that, we showed that NRF2 is PARylated that is absent in the cells in which PARP2 was silenced. Apparently, the PARylation of NRF2 by PARP2 has pivotal role in regulating the subcellular (nuclear) localization of NRF2. The silencing of PARP2 rearranged the expression of genes encoding proteins with antioxidant function, among these a subset of NRF2-dependent genes.
    DOI:  https://doi.org/10.1038/s41598-023-35076-w