bims-nurfca 2024-05-05 papers

Issue of 2024‒05‒05
five papers selected by
Caner Geyik, Istinye University

Phytomedicine. 2024 Apr 21. pii: S0944-7113(24)00320-9. [Epub ahead of print]129 155661

Dihydrotanshinone I inhibits gallbladder cancer growth by targeting the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation.

Zhuang Li, Rong-Liang Mo, Jun-Feng Gong, Lin Han, Wen-Fei Wang, Da-Ke Huang, Jie-Gou Xu, Yan-Jun Sun, Shuo Chen, Gen-Cheng Han, Deng-Qun Sun.

BACKGROUND: Gallbladder cancer (GBC) poses a significant risk to human health. Its development is influenced by numerous factors, particularly the homeostasis of reactive oxygen species (ROS) within cells. This homeostasis is crucial for tumor cell survival, and abnormal regulation of ROS is associated with the occurrence and progression of many cancers. Dihydrotanshinone I (DHT I), a biologically effective ingredient isolated from Salvia miltiorrhiza, has exhibited cytotoxic properties against various tumor cells by inducing apoptosis. However, the precise molecular mechanisms by which dht I exerts its cytotoxic effects remain unclear.PURPOSE: To explore the anti-tumor impact of dht I on GBC and elucidate the potential molecular mechanisms.
METHODS: The proliferation of GBC cells, NOZ and SGC-996, was assessed using various assays, including CCK-8 assay, colony formation assay and EdU staining. We also examined cell apoptosis, cell cycle progression, ROS levels, and alterations in mitochondrial membrane potential to delve into the intricate molecular mechanism. Quantitative PCR (qPCR), immunofluorescence staining, and Western blotting were performed to evaluate target gene expression at both the mRNA and protein levels. The correlation between nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap1) were examined using co-immunoprecipitation. Finally, the in vivo effect of dht I was investigated using a xenograft model of gallbladder cancer in mice.
RESULTS: Our research findings indicated that dht I exerted cytotoxic effects on GBC cells, including inhibiting proliferation, disrupting mitochondrial membrane potential, inducing oxidative stress and apoptosis. Our in vivo studies substantiated the inhibition of dht I on tumor growth in xenograft nude mice. Mechanistically, dht I primarily targeted Nrf2 by promoting Keap1 mediated Nrf2 degradation and inhibiting protein kinase C (PKC) induced Nrf2 phosphorylation. This leads to the suppression of Nrf2 nuclear translocation and reduction of its target gene expression. Moreover, Nrf2 overexpression effectively counteracted the anti-tumor effects of dht I, while Nrf2 knockdown significantly enhanced the inhibitory effect of dht I on GBC. Meanwhile, PKC inhibitors and nuclear import inhibitors increased the sensitivity of GBC cells to dht I treatment. Conversely, Nrf2 activators, proteasome inhibitors, antioxidants and PKC activators all antagonized dht I induced apoptosis and ROS generation in NOZ and SGC-996 cells.
CONCLUSION: Our findings indicated that dht I inhibited the growth of GBC cells by regulating the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation. These insights provide a strong rationale for further investigation of dht I as a potential therapeutic agent for GBC treatment.

Keywords: Apoptosis; Dihydrotanshinone I; Gallbladder carcinoma; Keap1-Nrf2 signaling pathway; Oxidative stress

DOI: https://doi.org/10.1016/j.phymed.2024.155661

J Cell Mol Med. 2024 May;28(9): e18209

Exosomal HSPB1, interacting with FUS protein, suppresses hypoxia-induced ferroptosis in pancreatic cancer by stabilizing Nrf2 mRNA and repressing P450.

Lun Zhang, Liuxu Yang, Keyuan Du.

Ferroptosis is a new type of programmed cell death, which has been involved in the progression of tumours. However, the regulatory network of ferroptosis in pancreatic cancer is still largely unknown. Here, using datasets from GEO and TCGA, we screened HSPB1, related to the P450 monooxygenase signalling, a fuel of ferroptosis, to be a candidate gene for regulating pancreatic cancer cell ferroptosis. We found that HSPB1 was enriched in the exosomes derived from human pancreatic cancer cell lines SW1990 and Panc-1. Then, hypoxic SW1990 cells were incubated with exosomes alone or together with HSPB1 siRNA (si-HSPB1), and we observed that exosomes promoted cell proliferation and invasion and suppressed ferroptosis, which was reversed by si-HSPB1. Moreover, we found a potential binding affinity between HSPB1 and FUS, verified their protein interaction by using dual-colour fluorescence colocalization and co-IP assays, and demonstrated the promoting effect of FUS on oxidative stress and ferroptosis in hypoxic SW1990 cells. Subsequently, FUS was demonstrated to bind with and stabilize the mRNA of Nrf2, a famous anti-ferroptosis gene that negatively regulates the level of P450. Furthermore, overexpressing FUS and activating the Nrf2/HO-1 pathway (using NK-252) both reversed the inhibitory effect of si-HSPB1 on exosome functions. Finally, our in vivo studies showed that exosome administration promote tumour growth in nude mice of xenotransplantation, which was able to be eliminated by knockdown of HSPB1. In conclusion, exosomal HSPB1 interacts with the RNA binding protein FUS and decreases FUS-mediated stability of Nrf2 mRNA, thus suppressing hypoxia-induced ferroptosis in pancreatic cancer.

Keywords: FUS; Nrf2/HO‐1/P450; exosomal HSPB1; ferroptosis; pancreatic cancer

DOI: https://doi.org/10.1111/jcmm.18209

Eur J Pharmacol. 2024 Apr 27. pii: S0014-2999(24)00308-X. [Epub ahead of print]974 176620

Oridonin promotes RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress signaling pathway JNK/Nrf2/HO-1.

Shiying Ye, Xiangyan Hu, Shaowei Sun, Bo Su, Jiye Cai, Jinhuan Jiang.

The incidence and mortality of breast cancer, the most common malignant tumor among women in the world, are increasing year by year, which greatly threatens women's health. Ferroptosis is an iron and lipid reactive oxygen species (ROS)-dependent process, a novel form of cell death that is distinct from apoptosis and is closely related to the progression of breast cancer. Inducing the occurrence of ferroptosis in tumor cells can effectively block its malignant progress in vivo. Oridonin (ORI), the primary active ingredient extracted from the Chinese herbal medicine Rabdosia rubescens, has been shown to cause glutathione depletion and directly inhibit glutathione peroxidase 4 induced cell death by ferroptosis, but its mechanism of action in breast cancer remains inadequately elucidated. Therefore, we further investigated whether ORI could promote RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress pathway JNK/Nrf2/HO-1. In our study, we assessed cell survival of RSL3 and ORI treatment by MTT assay, and found that co-treatment with RSL3 and ORI inhibited cell proliferation, as evidenced by the cloning assay. To investigate the ability of ORI to promote RSL3-induced ferroptosis in breast cancer cells, we measured levels of ROS, malondialdehyde, glutathione, superoxide dismutase, and Fe2+ content. Lipid peroxidation, ROS, and mitochondrial membrane potential levels induced by co-treatment of ORI with RSL3 were reversed by ferrostatin-1, further confirming that the cell death induced by RSL3 and ORI was ferroptosis rather than other programmed cell death modes. Moreover, RSL3 and ORI co-treatment regulated the JNK/Nrf2/HO-1 axis, as demonstrated by western blotting and target activator validation. Our results showed that ORI could enhance the inhibitory effect of RSL3 on breast cancer cells viability via the induction of ferroptosis. Mechanistically, it potentiated RSL3-induced ferroptosis in breast cancer cells by activating the JNK/Nrf2/HO-1 axis. This study provides a theoretical basis for the application of ORI based on the mechanism of ferroptosis, and provides potential natural drug candidates for cancer prevention and treatment.

Keywords: Breast cancer; Ferroptosis; JNK/Nrf2/HO-1; Oridonin; Oxidative stress

DOI: https://doi.org/10.1016/j.ejphar.2024.176620

J Cell Mol Med. 2024 May;28(9): e18318

Orexin-A mediates glioblastoma proliferation inhibition by increasing ferroptosis triggered by unstable iron pools and GPX4 depletion.

Rengzheng Huan, Jiqin Zhang, Jianhe Yue, Sha Yang, Guoqiang Han, Yuan Cheng, Ying Tan.

Glioblastoma (GBM) represents a prevalent form of primary malignant tumours in the central nervous system, but the options for effective treatment are extremely limited. Ferroptosis, as the most enriched programmed cell death process in glioma, makes a critical difference in glioma progression. Consequently, inducing ferroptosis has become an appealing strategy for tackling gliomas. Through the utilization of multi-omics sequencing data analysis, flow cytometry, MDA detection and transmission electron microscopy, the impact of orexin-A on ferroptosis in GBM was assessed. In this report, we provide the first evidence that orexin-A exerts inhibitory effects on GBM proliferation via the induction of ferroptosis. This induction is achieved by instigating an unsustainable increase in iron levels and depletion of GPX4. Moreover, the regulation of TFRC, FTH1 and GPX4 expression through the targeting of NFE2L2 appears to be one of the potential mechanisms underlying orexin-A-induced ferroptosis.

Keywords: ferroptosis; glioblastoma; orexin‐A

DOI: https://doi.org/10.1111/jcmm.18318

Biol Direct. 2024 Apr 29. 19(1): 32

NSUN2 relies on ALYREF to regulate Nrf2-mediated oxidative stress and alleviate Dox-induced liver injury.

Yingying Huang, Xiao Li, Lin Wei, Shinan Ma, Liming Ma, Yuxin Zan, Xiju He, Yijun Tang, Yan Ding.

BACKGROUND: Doxorubicin (Dox) is associated with various liver injuries, limiting its clinical utility. This study investigates whether NSUN2 participates in Dox-induced liver injury and the associated molecular mechanism.METHODS: In vivo and in vitro liver cell injury models were constructed based on Dox therapy. The protein levels of NSUN2 and oxidative stress indicators Nrf2, HO-1, and NQO1 were evaluated by Western blot. The RNA binding potential was detected by RNA methylation immunoprecipitation (RIP). Additionally, the effect of NSUN2 on Nrf2 mRNA synthesis and localization was evaluated using an RNA fluorescence probe.
RESULTS: NSUN2 was downregulated, and liver tissue suffered significant pathological damage in the Dox group. The levels of ALT and AST significantly increased. NSUN2 interference exacerbated Dox-induced liver cell damage, which was reversed by NSUN2 overexpression. RIP demonstrated that NSUN2 recognized and bound to Nrf2 mRNA. Western blot analysis showed the protein level of Nrf2 in the NSUN2-WT group was significantly higher than that of the control group, whereas there was no significant change in Nrf2 level in the mutant NSUN2 group. Luciferase analysis demonstrated that NSUN2 could recognize and activate the Nrf2 5'UTR region of LO2 cells. In addition, RIP analysis revealed that ALYREF could recognize and bind to Nrf2 mRNA and that ALYREF controls the regulatory effect of NSUN2 on Nrf2.
CONCLUSION: NSUN2 regulates Dox-induced liver cell damage by increasing Nrf2 mRNA m5C methylation to inhibit inhibiting antioxidant stress. The regulatory effect of NSUN2 on Nrf2 depends on ALYREF.

Keywords: ALYREF; Liver injury; NSUN2; Nrf2; m5C

DOI: https://doi.org/10.1186/s13062-024-00477-y