miR-200c is a tumor suppressor miRNA that plays a critical role in regulating epithelial phenotype and cancer stemness. p53 deficiency downregulates the expression of miR-200c and leads to epithelial-mesenchymal transition (EMT) and stemness phenotype, which contributes to the progression of breast cancers. In this study, we demonstrated that CRISPR-mediated knockout (KO) of miR-200c induces metabolic features similar to the metabolic rewiring caused by p53 hot-spot mutations, and that impairing this metabolic reprogramming interferes with miR-200c deficiency–induced stemness and transformation. Moreover, restoring miR-200c expression compromised EMT, stem-cell properties, and the Warburg effect caused by p53 mutations, suggesting that mutant p53 (MTp53) induces EMT-associated phenotypes and metabolic reprogramming by downregulating miR-200c. Mechanistically, decreased expression of PCK2 was observed in miR-200c– and p53-deficient mammary epithelial cells, and forced expression of miR-200c restored PCK2 in p53 mutant–expressing cells. Reduced PCK2 expression not only led to attenuated oxidative phosphorylation (OXPHOS) and increased stemness in normal mammary epithelial cells but also compromised the enhanced OXPHOS and suppression of cancer stemness exerted by miR-200c in p53 mutation–bearing basal-like breast cancer (BLBC) cells. Clinically, PCK2 expression is negatively associated with EMT markers and is downregulated in basal-like subtype and cases with low miR-200c expression or p53 mutation. Notably, low expression of PCK2 is associated with poor overall survival (OS) in patients with breast cancer. Implications: Together, our results suggest that p53 and miR-200c regulate OXPHOS and stem/cancer stemness through PCK2, and loss of the p53–miR-200c–PCK2 axis might provide metabolic advantages that facilitate cancer stemness, leading to the progression of BLBCs.

中文翻译：

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突变 p53 通过下调基底样乳腺癌中的 miR-200c-PCK2 轴减弱氧化磷酸化并促进癌症干性

miR-200c 是一种肿瘤抑制 miRNA，在调节上皮表型和癌症干性中起关键作用。p53 缺乏会下调 miR-200c 的表达并导致上皮间质转化 (EMT) 和干细胞表型，这有助于乳腺癌的进展。在这项研究中，我们证明了 CRISPR 介导的 miR-200c 敲除 (KO) 诱导的代谢特征类似于由 p53 热点突变引起的代谢重连，并且削弱这种代谢重编程会干扰 miR-200c 缺乏诱导的干性和转型。此外，恢复 miR-200c 表达会损害 EMT、干细胞特性和 p53 突变引起的 Warburg 效应，这表明突变 p53 (MTp53) 通过下调 miR-200c 诱导 EMT 相关表型和代谢重编程。从机制上讲，在 miR-200c 和 p53 缺陷的乳腺上皮细胞中观察到 PCK2 的表达降低，并且 miR-200c 的强制表达恢复了 p53 突变体表达细胞中的 PCK2。PCK2 表达降低不仅导致正常乳腺上皮细胞中氧化磷酸化 (OXPHOS) 减弱和干性增加，而且还损害了 miR-200c 在携带 p53 突变的基底样乳腺癌 (BLBC) 中增强的 OXPHOS 和抑制癌症干性细胞。临床上，PCK2 表达与 EMT 标志物呈负相关，并且在基底样亚型和 miR-200c 低表达或 p53 突变的病例中下调。值得注意的是，PCK2 的低表达与乳腺癌患者较差的总生存期 (OS) 相关。影响：一起，