Breast cancer cells evade cell death by overexpressing SLC7A11, which functions by transporting cystine into cells in exchange for intracellular glutamate facilitating glutathione synthesis and reducing reactive oxygen species (ROS)–mediated stress. Using an in silico approach, we predicted an miRNA (miR-5096) that can target and downregulate SLC7A11. We demonstrated SLC7A11 as a target of miR-5096 by 3′UTR luciferase assay and further validated it by identifying reduced mRNA and protein levels of SLC7A11 upon miR-5096 overexpression. miR-5096–induced ferroptotic cell death in human breast cancer cells was confirmed by concurrently increased ROS, OH⁻, lipid ROS, and iron accumulation levels and decreased GSH and mitochondrial membrane potential (MitoTracker™ Orange) with mitochondrial shrinkage and partial cristae loss (observed by TEM). miR-5096 inhibited colony formation, transwell migration, and breast cancer cell invasion, whereas antimiR-5096 promoted these tumorigenic properties. Ectopic expression of SLC7A11 partly reversed miR-5096-mediated effects on cell survival, ROS, lipid peroxides, iron accumulation, GSH, hydroxyl radicals, mitochondrial membrane potential, and colony formation. miR-5096 modulated the expression of epithelial-mesenchymal transition markers in vitro and inhibited the metastatic potential of MDA-MB-231 cells in a tumor xenograft model of zebrafish larvae. Our results demonstrate that miR-5096 is a tumor-suppressive miRNA in breast cancer cells, and this paper discusses its therapeutic implications.

乳腺癌细胞通过过度表达 SLC7A11 来逃避细胞死亡，SLC7A11 通过将胱氨酸转运到细胞中以换取细胞内谷氨酸促进谷胱甘肽合成和减少活性氧 (ROS) 介导的压力。使用计算机方法，我们预测了一种可以靶向和下调 SLC7A11 的 miRNA (miR-5096)。我们通过 3'UTR 荧光素酶测定证明 SLC7A11 作为 miR-5096 的靶标，并通过鉴定 miR-5096 过表达后 SLC7A11 的 mRNA 和蛋白质水平降低来进一步验证它。miR-5096 诱导的人乳腺癌细胞中的铁死亡细胞死亡通过同时增加的 ROS、OH 得到证实^-、脂质 ROS 和铁积累水平以及 GSH 和线粒体膜电位（MitoTracker™ Orange）降低，线粒体收缩和部分嵴缺失（通过 TEM 观察）。miR-5096 抑制集落形成、transwell 迁移和乳腺癌细胞侵袭，而 antimiR-5096 促进这些致瘤特性。SLC7A11 的异位表达部分逆转了 miR-5096 介导的对细胞存活、活性氧、脂质过氧化物、铁积累、谷胱甘肽、羟基自由基、线粒体膜电位和集落形成的影响。miR-5096在体外调节上皮-间质转化标志物的表达并在斑马鱼幼虫的肿瘤异种移植模型中抑制 MDA-MB-231 细胞的转移潜能。我们的研究结果表明 miR-5096 是乳腺癌细胞中的一种肿瘤抑制 miRNA，本文讨论了它的治疗意义。