背景:治疗结直肠癌(CRC)仍然是一个临床挑战。研究表明,上皮-间质转化(EMT)是肿瘤进展的关键步骤,转化生长因子-β1(TGF-β1)信号在EMT中起关键作用。这里,研究人参的主要生物活性成分人参皂苷Rb2的抑制作用,在人类结直肠癌细胞中通过TGF-β1。
目的:本研究旨在研究人参皂苷Rb2对HCT116和SW620细胞的抑制作用及其抗肿瘤机制。
方法:进行组织形态学分析和蛋白质印迹分析以评估人类癌性结肠样本和邻近正常样本中TGF-β1的表达。通过对接模拟实验探索人参皂苷Rb2与TGF-β1蛋白结合的潜在模式。用CCK8、粘附和侵袭实验评价人参皂苷Rb2对HCT116和SW620细胞的影响。RT-PCR,蛋白质印迹和免疫组织化学染色用于检测结肠癌细胞和/或异种移植小鼠中TGF-β1相关的信号通路。
结果:与癌旁正常样本相比,人结肠癌样本中TGF-β1的表达显着增加。人参皂苷Rb2抑制生长,附着力,EMT与人大肠癌细胞的转移。对接模拟试验证实人参皂苷Rb2与TGF-β1的疏水口袋结合,与TGF-β1上的结合位点部分重叠,从而破坏了TGF-β1的二聚化。WesternBlot分析进一步证实人参皂苷Rb2在体内和体外均能抑制TGF-β1的表达。此外,人参皂苷Rb2可以抑制Smad4的表达和磷酸化Smad2/3。
结论:人参皂苷Rb2可通过TGF-β1/Smad信号抑制大肠癌细胞的EMT,并且可能是治疗结直肠癌的潜在候选者。
BACKGROUND: Treating colorectal cancer (CRC) continues to be a clinical challenge. Studies have shown that epithelial-mesenchymal transition (EMT) is a critical step in tumor progression and transforming growth factor-β1 (TGF-β1) signaling has been shown to play a crucial role in EMT. Here, we investigate the inhibition effect of Ginsenoside Rb2, main bioactive component of ginseng, in human colorectal cancer cells via TGF-β1.
OBJECTIVE: The current study aims to study the inhibitory effect of Ginsenoside Rb2 on HCT116 and SW620 cells and its anti-tumor mechanism.
METHODS: Histomorphological analysis and western blot analysis were performed to evaluate expression of TGF-β1 in human cancerous colon samples and the adjacent normal samples. The docking simulation assay were performed to explore the potential mode of binding of Ginsenoside Rb2 to the TGF-β1 protein. CCK8, adhesion and invasion assay were used to assess the effects of Ginsenoside Rb2 in HCT116 and SW620 cells. RT-PCR, Western blot and Immunohistochemical staining were employed to detect the TGF-β1-related signaling pathways in the colon cancer cells and/or xenograft mice.
RESULTS: The expression of TGF-β1 in human cancerous colon samples was significantly increased compared with the adjacent normal samples. Ginsenoside Rb2 inhibit the growth, adhesion, EMT and metastasis of human colorectal cancer cells. The docking simulation assay confirmed that Ginsenoside Rb2 bound to the hydrophobic pocket of TGF-β1, which partially overlaps with the binding sites on TGF-β1, and thus disrupted TGF-β1 dimerization. Western Blot analysis further confirmed that Ginsenoside Rb2 could inhibit the expression of TGF-β1 in vitro and in vivo. Furthermore, Ginsenoside Rb2 could inhibit the expression of Smad4 and phosphorylated Smad2/3.
CONCLUSIONS: Ginsenoside Rb2 could inhibit EMT of colorectal cancer cells through the TGF-β1/Smad signaling, and might be a potential candidate for the treatment of colorectal cancer.