多叶贝母草（Polyphyllin D，PD）是传统药用植物川贝母中重要的类固醇皂苷之一，已被证明具有体外和体内的抗癌活性。然而，PD在三阴性乳腺癌（TNBC）中发挥抗癌作用的机制仍不清楚。我们的研究旨在评估PD在两种TNBC细胞系（BT-549和MDA-MB-231）中的抗癌效果及其潜在机制。通过全面比较PD处理和未处理的BT-549和MDA-MB-231细胞的液相色谱串联质谱（LC-MS/MS）数据，我们发现PD能够通过激活BT-549细胞的氧化磷酸化途径以及抑制MDA-MB-231细胞的剪接体功能改变来诱导TNBC细胞的凋亡。这些结果表明，PD对TNBC的促凋亡效应的机制可能受细胞类型特异性的影响。此外，我们发现PD处理的BT-549和MDA-MB-231细胞中，节点调节因子2/3（NOMO2/3）均下调，提示NOMO2/3可能是PD的潜在靶点。验证实验揭示PD在蛋白水平上降低NOMO2/3的表达，而不是mRNA水平上的降低。关于NOMO2/3是否是氧化磷酸化途径和剪接体的上游调节因子，需要进一步验证。总之，我们对PD处理或未处理的TNBC细胞进行了全面的蛋白质组学研究，揭示了PD的抗癌机制。© 2023。作者。

Polyphyllin D (PD), one of the important steroid saponins in traditional medicinal herb Paris polyphylla, has been demonstrated to have anticancer activity both in vitro and in vivo. However, the mechanisms through which PD exerts its anticancer effects in triple-negative breast cancer (TNBC) remain unclear. Our study was presented to evaluate the anticancer effect and the potential mechanisms of PD in two TNBC cell lines, BT-549 and MDA-MB-231. Through comprehensively comparing the liquid chromatography-tandem mass spectrometry (LC-MS/MS) data of PD-treated and untreated BT-549 and MDA-MB-231 cells, we found that PD could induce apoptosis of TNBC cells by activating oxidative phosphorylation pathway in BT-549 cells, as well as inhibiting spliceosome function alteration in MDA-MB-231 cells. These results suggested that the mechanisms underlying the pro-apoptotic effect of PD on TNBC may be cell type-specificity-dependent. Moreover, we found that nodal modulator 2/3 (NOMO2/3) were downregulated both in PD-treated BT-549 and MDA-MB-231 cells, suggesting that NOMO2/3 may be the potential target of PD. Verification experiments revealed that PD deceased NOMO2/3 expression at protein level, rather than mRNA level. Whether NOMO2/3 are the upstream modulators of oxidative phosphorylation pathway and spliceosome needs further validation. In conclusion, a comprehensive proteomics study was performed on PD-treated or untreated TNBC cells, revealing the anticancer mechanisms of PD.© 2023. The Author(s).