Ferroptosis is an autophagy-dependent cell death associated with iron accumulation and lipid peroxidation, which plays a crucial part in anticancer activity. Sirtuin 3 (SIRT3) positively regulates autophagy by phosphorylation of activated protein kinase (AMPK). However, whether SIRT3-mediated autophagy can inhibit the cystine/glutamate antiporter (system Xc⁻) activity by inducing the formation of a BECN1-SLC7A11 complex and consequently promote induction of ferroptosis is unknown. Using both in vitro and in vivo models, we revealed that combination treatment with erastin and TGF-β1 decreased the expression of epithelial-mesenchymal transition-related markers and inhibited the invasion and metastasis of breast cancer. Furthermore, TGF-β1 promoted erastin-induced ferroptosis-related indicators in MCF-7 cells and tumor-bearing nude mice models. Interestingly, the expression of SIRT3, p-AMPK, and autophagy-related markers were significantly elevated after co-treatment with erastin and TGF-β1, suggesting that combination treatment of erastin and TGF-β1 mediated autophagy by the SIRT3/AMPK signaling pathway. In addition, erastin-induced BECN1-SLC7A11 complexes were more abundant after co-treatment with TGF-β1. This effect was inhibited by the autophagy inhibitor 3-methyladenine or siSIRT3, further revealing that combination treatment of erastin and TGF-β1 mediated autophagy-dependent ferroptosis by inducing the formation of BECN1-SLC7A11 complexes. Our results agreed with the concept that BECN1 directly binds to SLC7A11 to inhibit system Xc⁻ activity. In summary, our studies confirmed that SIRT3-mediated autophagy is conducive to ferroptosis-mediated anticancer activity by inducing the formation of BECN1-SLC7A11 complexes, which is a potential therapeutic approach for treating breast cancer.

铁死亡是一种与铁积累和脂质过氧化相关的自噬依赖性细胞死亡，在抗癌活性中发挥着至关重要的作用。Sirtuin 3 (SIRT3) 通过激活蛋白激酶 (AMPK) 的磷酸化来正向调节自噬。然而，SIRT3介导的自噬是否可以通过诱导BECN1-SLC7A11复合物的形成来抑制胱氨酸/谷氨酸逆向转运蛋白（系统Xc ^-）活性，从而促进铁死亡的诱导尚不清楚。利用体外和体内模型，我们发现，erastin和TGF-β1联合治疗可降低上皮间质转化相关标志物的表达，并抑制乳腺癌的侵袭和转移。此外，TGF-β1在MCF-7细胞和荷瘤裸鼠模型中促进erastin诱导的铁死亡相关指标。有趣的是，在erastin和TGF-β1联合治疗后，SIRT3、p-AMPK和自噬相关标志物的表达显着升高，表明erastin和TGF-β1联合治疗通过SIRT3/AMPK信号通路介导自噬。此外，与TGF-β1共同处理后，erastin诱导的BECN1-SLC7A11复合物更加丰富。这种效应被自噬抑制剂 3-甲基腺嘌呤或 siSIRT3 抑制，进一步揭示了erastin 和 TGF-β1 的联合治疗通过诱导 BECN1-SLC7A11 复合物的形成介导了自噬依赖性铁死亡。我们的结果与 BECN1 直接结合 SLC7A11 以抑制系统 Xc ^-活性的概念一致。总之，我们的研究证实SIRT3介导的自噬通过诱导BECN1-SLC7A11复合物的形成而有利于铁死亡介导的抗癌活性，这是治疗乳腺癌的潜在治疗方法。