Ginsenosides have been reported to possess various pharmacological effects, including anticancer effects. Nevertheless, there are few reports about the antitumor activity and mechanisms of ginsenoside Rg5 against breast cancer cells. In the present study, the major ginsenoside Rb1 was transformed into the rare ginsenoside Rg5 through enzymatic bioconversion and successive acid-assisted high temperature and pressure processing. Ginsenosides Rb1, Rg3, and Rg5 were investigated for their antitumor effects against five human cancer cell lines via the MTT assay. Among them, Rg5 exhibited the greatest cytotoxicity against breast cancer. Moreover, Rg5 remarkably suppressed breast cancer cell proliferation through mitochondria-mediated apoptosis and autophagic cell death. LC3B-GFP/Lysotracker and mRFP-EGFP-LC3B were utilized to show that Rg5 induced autophagosome-lysosome fusion. Western blot assays further illustrated that Rg5 decreased the phosphorylation levels of PI3K, Akt, mTOR, and Bad and suppressed the PI3K/Akt signaling pathway in breast cancer. Moreover, Rg5-induced apoptosis and autophagy could be dramatically strengthened by the PI3K/Akt inhibitor LY294002. Finally, a molecular docking study demonstrated that Rg5 could bind to the active pocket of PI3K. Collectively, our results revealed that Rg5 could be a potential therapeutic agent for breast cancer treatment.
人参皂苷已被报道具有多种药理学效应,包括抗癌效应。然而,关于
人参皂苷Rg5对乳腺癌细胞的抗肿瘤活性和机制的报道很少。在本研究中,通过酶促
生物转化和连续的酸辅助高温高压处理,将主要的
人参皂苷Rb1转化为罕见的
人参皂苷Rg5。通过M
TT实验,研究了
人参皂苷Rb1、Rg3和Rg5对五种人类癌
细胞系的抗肿瘤效应。其中,Rg5对乳腺癌表现出最强的细胞毒性。此外,Rg5通过线粒体介导的凋亡和自噬
细胞死亡显著抑制了乳腺癌细胞的增殖。使用LC3B-GFP/Lysotracker和mRFP-
EGFP-LC3B表明,Rg5诱导自噬体-溶酶体融合。Western blot实验证明,Rg5降低了
PI3K、Akt、mTOR和Bad的
磷酸化
水平,并抑制了
PI3K/Akt信号通路在乳腺癌中的作用。此外,Rg5诱导的凋亡和自噬可被
PI3K/Akt
抑制剂LY294002显著增强。最后,分子对接研究表明,Rg5可以结合到
PI3K的活性口袋。总之,我们的结果揭示了Rg5可能成为乳腺癌治疗的潜在治疗药物。