Abstract：
The exploration of drugs derived from natural sources holds significant promise in addressing current limitations in ovarian cancer (OC) treatments. While previous studies have highlighted the remarkable anti-cancer properties of the natural compound β-sitosterol (SIT) across various tumors, its specific role in OC treatment remains unexplored. This study aims to investigate the anti-tumor activity of SIT in OC using in vitro and in vivo models, delineate potential mechanisms, and establish a preclinical theoretical foundation for future clinical trials, thus fostering further research. Utilizing network pharmacology, we pinpoint SIT as a promising candidate for OC treatment and predict its potential targets and pathways. Through a series of in vitro and in vivo experiments, we unveil a novel mechanism through which SIT mitigates the malignant biological behaviors of OC cells by modulating redox status. Specifically, SIT selectively targets argininosuccinate synthetase 1 (ASS1), a protein markedly overexpressed in OC tissues and cells. Inhibiting ASS1, SIT enhances the interaction between Nrf2 and Keap1, instigating the ubiquitin-dependent degradation of Nrf2, subsequently diminishing the transcriptional activation of downstream antioxidant genes HO-1 and NQO1. The interruption of the antioxidant program by SIT results in the substantial accumulation of reactive oxygen species (ROS) in OC cells. This, in turn, upregulates PTEN, exerting negative regulation on the phosphorylation activation of AKT. The suppression of AKT signaling disrupted downstream pathways associated with cell cycle, cell survival, apoptosis, migration, and invasion, ultimately culminating in the death of OC cells. Our research uncovers new targets and mechanisms of SIT against OC, contributing to the existing knowledge on the anti-tumor effects of natural products in the context of OC. Additionally, this research unveils a novel role of ASS1 in regulating the Nrf2-mediated antioxidant program and governing redox homeostasis in OC, providing a deeper understanding of this complex disease.
摘要：
来自天然来源的药物的探索在解决卵巢癌（OC）治疗中的当前局限性方面具有重要的前景。虽然先前的研究强调了天然化合物β-谷甾醇（SIT）在各种肿瘤中的显着抗癌特性，其在OC治疗中的具体作用仍有待探索。本研究旨在利用体外和体内模型研究SIT在OC中的抗肿瘤活性。描绘潜在的机制，并为未来的临床试验建立临床前理论基础，从而促进进一步的研究。利用网络药理学，我们确定SIT是OC治疗的有希望的候选药物,并预测其潜在的靶点和途径.通过一系列的体外和体内实验,我们揭示了SIT通过调节氧化还原状态减轻OC细胞恶性生物学行为的新机制。具体来说,SIT选择性靶向精氨酸琥珀酸合成酶1（ASS1），在OC组织和细胞中明显过表达的蛋白质。抑制ASS1，SIT增强Nrf2和Keap1之间的相互作用，促使Nrf2的泛素依赖性降解，随后减少下游抗氧化基因HO-1和NQO1的转录激活。SIT对抗氧化剂程序的中断导致OC细胞中活性氧（ROS）的大量积累。这个,反过来,上调PTEN,对AKT的磷酸化激活施加负调控。AKT信号的抑制破坏了与细胞周期相关的下游通路，细胞存活,凋亡，迁移,和入侵,最终导致OC细胞死亡。我们的研究发现了SIT对抗OC的新目标和机制，有助于在OC背景下对天然产物抗肿瘤作用的现有知识。此外,这项研究揭示了ASS1在调节Nrf2介导的抗氧化剂程序和控制OC中的氧化还原稳态方面的新作用，提供了对这种复杂疾病的更深入的了解。
