Table_1_Ailanthone Inhibits Proliferation, Migration and Invasion of Osteosarcoma Cells by Downregulating the Serine Biosynthetic Pathway.xlsx

Osteosarcoma (OS) is the most common primary bone sarcoma, chemoresistance becomes an obstacle to its treatment. Metabolic reprogramming is a hallmark of malignancy, targeting the metabolic pathways might provide a reasonable therapeutic strategy for OS. Here we demonstrated that Ailanthone (AIL), a major component of the Chinese medicine Ailanthus altissima, significantly suppressed OS cell growth in vitro and in vivo. Furthermore, AIL dose-dependently inhibited cell migration and invasion, induced cell cycle arrest and apoptosis in OS cells. Combined transcriptomics, proteomics and metabolomics analyses revealed that AIL induced widespread changes in metabolic programs in OS cells, while the serine biosynthetic pathway (SSP) was the most significantly altered pathway. qRT-PCR and Western blot assay confirmed that the transcript and protein levels of the SSP genes (PHGDH, PSAT1 and PSPH) were downregulated dose-dependently by AIL. In addition, we found out that many downstream pathways of the SSP including the one-carbon pool by folate, purine metabolism, pyrimidine metabolism, DNA replication and sphingolipid metabolism were downregulated after AIL treatment. In the revere test, PHGDH overexpression but not exogenous serine supplementation clearly attenuated the effects of AIL on OS cells. Taken together, AIL exerts antitumor effects on OS through mediating metabolic reprogramming, at least in part, by suppressing the SSP. Our findings suggest that AIL could emerge as a potential therapeutic strategy in OS.

骨肉瘤（OS）是原发性骨肉瘤中最常见的类型，化疗耐药性已成为其治疗的一大障碍。代谢重编程是恶性肿瘤的标志之一，针对代谢途径可能为骨肉瘤提供一种合理的治疗策略。本研究中，我们展示了阿米兰（AIL），作为中国药材苦楝树的主要成分，在体外和体内显著抑制了骨肉瘤细胞的生长。此外，AIL剂量依赖性地抑制了细胞的迁移和侵袭，并诱导了骨肉瘤细胞周期的停滞和凋亡。结合转录组学、蛋白质组学和代谢组学分析，我们发现AIL在骨肉瘤细胞中引起了广泛的代谢程序变化，其中丝氨酸生物合成途径（SSP）是变化最为显著的途径。定量RT-PCR和Western blot实验证实，AIL通过剂量依赖性地下调SSP基因（PHGDH、PSAT1和PSPH）的转录和蛋白水平。此外，我们发现许多SSP的下游途径，包括一碳池由叶酸、嘌呤代谢、嘧啶代谢、DNA复制和鞘脂代谢等，在AIL处理后均下调。在逆转实验中，PHGDH过表达而非外源性丝氨酸补充明显减弱了AIL对骨肉瘤细胞的影响。综上所述，AIL通过介导代谢重编程，至少部分地通过抑制SSP发挥抗肿瘤作用，我们的研究结果表明，AIL可能成为骨肉瘤治疗的一种潜在策略。