Department of Colorectal Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China.
Department of Anorectal Surgery, The Shenzhen Hospital of Southern Medical University, Southern Medical University, Shenzhen, China.
Int J Biochem Cell Biol. 2020 Aug;125:105777. doi: 10.1016/j.biocel.2020.105777. Epub 2020 Jun 3.
Fraxetin, extracted from the bark of Fraxinus rhynchophylla, has been shown to exhibit antitumour and anti-inflammatory pharmacological properties. However, the mechanism underlying its anticancer activity towards colon adenocarcinoma (COAD) is not well understood. We aimed to determine the antitumour effect of fraxetin on COAD cell lines and elucidate its biochemical and molecular targets.
The cell lines HCT116 and DLD-1 were used to evaluate the in vitro antitumour efficacy of fraxetin. Cytotoxicity and viability were assessed by CCK-8 and plate colony formation assays. Flow cytometry was used to assess apoptosis and cell cycle progression in fraxetin-treated COAD cells. Western blot, RT-qPCR, molecular docking, immunohistochemical, and immunofluorescence analyses were used to gain insights into cellular and molecular mechanisms. Preclinical curative effects were evaluated in nude mouse xenograft models.
Fraxetin significantly inhibited COAD cell proliferation in both dose- and time-dependent manners, specifically by inducing S-phase cell cycle arrest and triggering intrinsic apoptosis. Additionally, the level of p-JAK2 was decreased by fraxetin via the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signalling pathway. Interestingly, in COAD cells, fraxetin directly targeted the Y and Y residues of JAK2 to suppress its auto- or transphosphorylation, leading to decreased activation of its downstream effector STAT3 and blocking its nuclear translocation. Finally, fraxetin exhibited good tumour growth suppression activity and low toxicity.
Fraxetin inhibits the proliferation of COAD cells by regulating the JAK2/STAT3 signalling pathway, providing evidence that targeting JAK2 with fraxetin may offer a novel potential auxiliary therapy for COAD treatment.
从水曲柳树皮中提取的水飞蓟素已显示出抗肿瘤和抗炎的药理作用。然而，其对结肠腺癌（COAD）的抗癌活性的机制尚不清楚。我们旨在确定水飞蓟素对 COAD 细胞系的抗肿瘤作用，并阐明其生化和分子靶点。
使用 HCT116 和 DLD-1 细胞系评估水飞蓟素的体外抗肿瘤功效。通过 CCK-8 和平板集落形成测定法评估细胞毒性和活力。流式细胞术用于评估水飞蓟素处理的 COAD 细胞中的细胞凋亡和细胞周期进程。Western blot、RT-qPCR、分子对接、免疫组织化学和免疫荧光分析用于深入了解细胞和分子机制。在裸鼠异种移植模型中评估临床前疗效。
水飞蓟素在剂量和时间依赖性方式下显著抑制 COAD 细胞增殖，特别是通过诱导 S 期细胞周期停滞和触发内在凋亡。此外，水飞蓟素通过 Janus 激酶 2/信号转导和转录激活因子 3（JAK2/STAT3）信号通路降低了 p-JAK2 的水平。有趣的是，在 COAD 细胞中，水飞蓟素直接靶向 JAK2 的 Y 和 Y 残基以抑制其自身或转磷酸化，从而降低其下游效应物 STAT3 的激活并阻止其核易位。最后，水飞蓟素表现出良好的肿瘤生长抑制活性和低毒性。
水飞蓟素通过调节 JAK2/STAT3 信号通路抑制 COAD 细胞的增殖，为靶向 JAK2 的水飞蓟素可能为 COAD 治疗提供一种新的潜在辅助治疗方法提供了证据。
