Lin Zhirong, Liu Zifei, Pan Zhilong, Zhang Yunyi, Yang Xinyu, Feng Yaxin, Zhang Ruihua, Zeng Wenfeng, Gong Chang, Chen Jianing
Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
J Cancer. 2024 Jun 24;15(14):4577-4590. doi: 10.7150/jca.95328. eCollection 2024.
Early growth response 1 (EGR1) is a crucial transcription factor composed of zinc finger structures, inhibitory and activating regulatory regions. We identified the biological effect and molecular mechanisms of EGR1 in breast cancer (BC). We used qRT-PCR, western blot and immunohistochemistry to examine the expression of EGR1 in BC samples. CCK-8 and colony assay were performed to reveal the effect of EGR1 on the proliferation of BC cells. LDH release assay, MCB assay, MDA assay, C-AM assay and TMRE assay were performed to measure the levels of LDH release, GSH, MDA, LIP and mitochondrial membrane potential. The regulation of EGR1 on the expression of Nrf2 and HMOX1 was investigated through Western blot. Xenograft models were conducted to determine the impact of EGR1 overexpression on BC . The expression of EGR1 was downregulated in BC tissues compared with the normal tissues, and lower expression of EGR1 associated with poorer clinical outcome in BC patients. Through experiments, we found that EGR1 downregulation facilitated the proliferation of BC cells, and overexpression of EGR1 inhibited the proliferation of BC cells. In addition, EGR1 knockdown alleviated erastin-induced ferroptosis and overexpression of EGR1 facilitated erastin-induced ferroptosis in BC cells. Moreover, overexpression of EGR1 facilitated the anti-tumor effect caused by erastin . Mechanistically, the phosphorylation levels of Nrf2 and the expression of HMOX1 were reduced due to the downregulation of EGR1, and increased due to the upregulation of EGR1. Additionally, the finding that EGR1 facilitated erastin-induced ferroptosis was alleviated by the inhibition of Nrf2-HMOX1. The expression of EGR1 is downregulated in BC, which is correlated with poor prognosis of BC patients. EGR1 suppresses the proliferation of BC cells and facilitates erastin-induced ferroptosis by activating Nrf2-HMOX1 signaling pathway in BC cells.
早期生长反应1（EGR1）是一种由锌指结构、抑制性和激活调节区域组成的关键转录因子。我们确定了EGR1在乳腺癌（BC）中的生物学效应和分子机制。我们使用qRT-PCR、蛋白质免疫印迹和免疫组织化学检测BC样本中EGR1的表达。进行CCK-8和集落测定以揭示EGR1对BC细胞增殖的影响。进行乳酸脱氢酶（LDH）释放测定、微量胱天蛋白酶（MCB）测定、丙二醛（MDA）测定、细胞内脂质（C-AM）测定和四甲基罗丹明乙酯（TMRE）测定以测量LDH释放、谷胱甘肽（GSH）、MDA、脂质（LIP）和线粒体膜电位水平。通过蛋白质免疫印迹研究EGR1对核因子E2相关因子2（Nrf2）和血红素加氧酶1（HMOX1）表达的调节。进行异种移植模型以确定EGR1过表达对BC的影响。与正常组织相比，BC组织中EGR1的表达下调，并且BC患者中EGR1表达较低与较差的临床结果相关。通过实验，我们发现EGR1下调促进了BC细胞的增殖，而EGR1过表达抑制了BC细胞的增殖。此外，敲低EGR1减轻了埃拉斯汀诱导的铁死亡，而EGR1过表达促进了埃拉斯汀诱导的BC细胞铁死亡。此外，EGR1过表达促进了埃拉斯汀引起的抗肿瘤作用。机制上，由于EGR1下调，Nrf2的磷酸化水平和HMOX1的表达降低，而由于EGR1上调而升高。此外，抑制Nrf2-HMOX1减轻了EGR1促进埃拉斯汀诱导的铁死亡这一发现。BC中EGR1的表达下调，这与BC患者的不良预后相关。EGR1通过激活BC细胞中的Nrf2-HMOX1信号通路抑制BC细胞的增殖并促进埃拉斯汀诱导的铁死亡。
