The Department of Biochemistry, Medicine School, Yichun University, Yichun 336000, China.
Genes (Basel). 2024 Oct 14;15(10):1316. doi: 10.3390/genes15101316.
Estrogen receptor-positive breast cancer accounts for around 70% of all cases. Tamoxifen, an anti-estrogenic inhibitor, is the primary drug used for this type of breast cancer treatment. However, tamoxifen resistance is a major challenge in clinics. Metabolic reprogramming, an emerging hallmark of cancer, plays a key role in cancer initiation, progression, and therapy resistance. The metabolism of non-essential amino acids such as serine, proline, and glutamine is involved in tumor metabolism reprogramming. Although the association of glutamine metabolism with tamoxifen resistance has been well established, the role of proline metabolism and its critical enzyme PRODH is unknown.
The aim of this study is to explore the role and mechanism of PRODH in tamoxifen resistance in breast cancer cells.
PRODH and GPX4 expressions in tamoxifen-resistant cells were detected using real-time PCR and Western blot analysis. The breast cells' response to tamoxifen was measured using MTT assays. Trans-well assays were used to detect cell migration and invasion. A Xenograft tumor assay was used to detect the role of PRODH in tumor growth. Reactive oxygen species were measured using flow cytometry.
PRODH expression is reduced in tamoxifen-resistant cells, and its overexpression enhances tamoxifen response in vitro and in vivo. Conversely, PRODH knockdown confers tamoxifen resistance in tamoxifen-sensitive cells. Mechanistic studies show that ferroptosis is inhibited in tamoxifen-resistant cells and overexpression of PRODH restores the ferroptosis in tamoxifen-resistant cells. Moreover, Ferrostatin-1 (Fer-1), the ferroptosis inhibitor, reversed the effect of PRODH on tamoxifen resistance.
These findings suggest that PRODH regulates tamoxifen resistance by regulating ferroptosis in tamoxifen-resistant cells.
雌激素受体阳性乳腺癌约占所有病例的 70%。他莫昔芬是一种抗雌激素抑制剂，是治疗这种乳腺癌的主要药物。然而，他莫昔芬耐药是临床的主要挑战。代谢重编程是癌症的一个新兴标志，在癌症的发生、发展和治疗耐药中起着关键作用。非必需氨基酸如丝氨酸、脯氨酸和谷氨酸的代谢参与了肿瘤代谢重编程。尽管谷氨酰胺代谢与他莫昔芬耐药的相关性已得到充分证实，但脯氨酸代谢及其关键酶 PRODH 的作用尚不清楚。
本研究旨在探讨 PRODH 在乳腺癌细胞中对他莫昔芬耐药的作用和机制。
采用实时 PCR 和 Western blot 分析检测他莫昔芬耐药细胞中 PRODH 和 GPX4 的表达。用 MTT 法检测乳腺癌细胞对他莫昔芬的反应。用 Trans-well 测定法检测细胞迁移和侵袭。用 Xenograft 肿瘤测定法检测 PRODH 在肿瘤生长中的作用。用流式细胞术检测活性氧。
PRODH 在他莫昔芬耐药细胞中的表达降低，过表达 PRODH 可增强体外和体内的他莫昔芬反应。相反，PRODH 敲低可赋予他莫昔芬敏感细胞对他莫昔芬的耐药性。机制研究表明，铁死亡在他莫昔芬耐药细胞中被抑制，过表达 PRODH 可恢复他莫昔芬耐药细胞中的铁死亡。此外，铁死亡抑制剂 Ferrostatin-1（Fer-1）逆转了 PRODH 对他莫昔芬耐药性的影响。
这些发现表明，PRODH 通过调节他莫昔芬耐药细胞中的铁死亡来调节他莫昔芬耐药性。
