Convallatoxin promotes apoptosis and inhibits proliferation and angiogenesis through crosstalk between JAK2/STAT3 (T705) and mTOR/STAT3 (S727) signaling pathways in colorectal cancer
Convallatoxin promotes apoptosis and inhibits proliferation and angiogenesis through crosstalk between JAK2/STAT3 (T705) and mTOR/STAT3 (S727) signaling pathways in colorectal cancer
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铃兰毒素通过结直肠癌中 JAK2/STAT3 (T705) 和 mTOR/STAT3 (S727) 信号通路之间的串扰促进细胞凋亡并抑制增殖和血管生成
DOI：
10.1016/j.phymed.2020.153172
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发表时间：
2020-03-01
期刊：
影响因子：
7.9
通讯作者：
Jin, Xuejun
中科院分区：
文献类型：
--
作者：
Zhang, Zhi Hong;Li, Ming Yue;Jin, Xuejun
背景：STAT3的异常激活在肿瘤细胞中十分常见，它能促进肿瘤细胞的存活、细胞增殖、迁移、侵袭和血管生成。通过同源模建和分子对接、荧光素酶报告实验、四甲基偶氮唑蓝(四甲基偶氮唑盐)比色法、逆转录聚合酶链式反应(RT-PCR)、Western blotting和免疫荧光等方法，研究了三萜类化合物螺杆菌毒素的抗癌作用，并探讨了其是否通过干扰STAT3的激活而发挥作用。采用EDU标记实验、集落形成实验、流式细胞术、创面愈合实验、Matrigel Transwell侵袭实验和血管形成实验分析细胞增殖、凋亡、迁移、侵袭和血管生成的变化。在体内，在小鼠异种移植的HCT116细胞模型中评价了螺杆菌毒素的抗肿瘤活性。结果：螺杆菌毒素降低了结直肠癌细胞系的存活率。此外，该毒素通过JAK1、JAK2和Src途径减少PSTAT3(T705)，并通过PI3K-AKT-mTOR-STAT3途径抑制STAT3丝氨酸-727的磷酸化。有趣的是，我们在mTOR/STAT3和JAK/STAT3通路中发现了mTOR和JAK2之间的串扰，协同调节STAT3的激活，并在其中发挥作用。Convallatoxin还下调靶基因的表达，这些基因涉及细胞生存(如Survivin、Bclxl、Bcl2)、增殖(如Cyclin D1)、转移(如MMP9)和血管生成(如VEGF)。事实上，我们发现雷公藤毒素可抑制血管内皮细胞的管状形成、迁移和侵袭，并抑制其增殖。结论：本研究结果表明，通过JAK2/STAT3(T705)和mTOR/STAT3(S727)信号通路之间的串扰，可促进结直肠癌细胞的凋亡，抑制增殖和血管生成，提示其可能成为结直肠癌治疗的候选药物。
Background: Aberrant activation of STAT3 is frequently encountered and promotes survival, cellular proliferation, migration, invasion and angiogenesis in tumor cell. Convallatoxin, triterpenoid ingredient, exhibits anticancer pharmacological properties.Purpose: In this work, we investigated the anticancer potential of convallatoxin and explored whether convallatoxin mediates its effect through interference with the STAT3 activation in colorectal cancer cells.Methods: In vitro, the underlying mechanisms of convallatoxin at inhibiting STAT3 activation were investigated by homology modeling and molecular docking, luciferase reporter assay, MTT assay, RT-PCR, Western blotting and immunofluorescence assays. Changes in cellular proliferation, apoptosis, migration, invasion and angiogenesis were analyzed by EdU labeling assay, colony formation assay, flow cytometry assay, wound-healing assay, matrigel transwell invasion assay and tube formation assays. And in vivo, antitumor activity of convallatoxin was assessed in a murine xenograft model of HCT116 cells.Results: Convallatoxin decreased the viability of colorectal cancer lines. Moreover, convallatoxin reduced the PSTAT3 (T705) via the JAK1, JAK2, and Src pathways and inhibited serine-727 phosphorylation of STAT3 via the PI3K-AKT-mTOR-STAT3 pathways in colorectal cancer cells. Interestingly, we discovered the crosstalk between mTOR and JAK2 in mTOR/STAT3 and JAK/STAT3 pathways, which collaboratively regulated STAT3 activation and convallatoxin play a role in it. Convallatoxin also downregulated the expression of target genes involved cell survival (e.g., Survivin, Bcl-xl, Bcl-2), proliferation (e.g., Cyclin D1), metastasis (e.g., MMP-9), and angiogenesis (e.g., VEGF). Indeed, we found that convallatoxin inhibited tube formation, migration, and invasion of endothelial cells, and inhibited the proliferation. Finally, in vivo observations were confirmed by showing antitumor activity of convallatoxin in a murine xenograft model.Conclusion: The result of the current study show that convallatoxin promotes apoptosis and inhibits proliferation and angiogenesis through crosstalk between JAK2/STAT3 (T705) and mTOR/STAT3 (S727) signaling pathways in colorectal cancer cells and indicate that convallatoxin could be a valuable candidate for the development of colorectal cancer therapeutic.