Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
Department of Pharmacology, School of Pharmacy Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Fourth Military Medical University, Xi'an, China.
Thorac Cancer. 2019 Apr;10(4):848-855. doi: 10.1111/1759-7714.13013. Epub 2019 Feb 27.
ING5 is the last member of the Inhibitor of Growth (ING) candidate tumor suppressor family that has been implicated in multiple cellular functions, including cell cycle regulation, apoptosis, and chromatin remodeling. Our previous study showed that ING5 overexpression inhibits lung cancer aggressiveness and epithelial-mesenchymal transition (EMT), with unknown mechanisms.
Western blotting was used to detect total and phosphorylated levels of β-catenin and EMT-related proteins. Immunofluorescent staining was used to observe E-cadherin expression. Proliferation and colony formation, wound healing, and Transwell migration and invasion assays were performed to study the proliferative and invasive abilities of cancer cells.
ING5 overexpression promotes phosphorylation of β-catenin at Ser33/37, leading to a decreased β-catenin protein level. Small hairpin RNA-mediated ING5 knockdown significantly increased the β-catenin level and inhibited phosphorylation of β-catenin S33/37. Treatment with the WNT/β-catenin inhibitor XAV939 inhibited ING5-knockdown promoted proliferation, colony formation, migration, and invasion of lung cancer A549 cells, with increased phosphorylation of β-catenin S33/37 and a decreased β-catenin level. XAV939 also impaired ING5-knockdown-induced EMT, as indicated by upregulated expression of the EMT marker E-cadherin, an epithelial marker; and decreased expression of N-cadherin, a mesenchymal marker, and EMT-related transcription factors, including Snail, Slug, Twist, and Smad3. Furthermore, XAV939 could inhibit the activation of both IL-6/STAT3 and PI3K/Akt signaling pathways.
ING5 inhibits lung cancer invasion and EMT by inhibiting the WNT/β-catenin pathway.
ING5 是抑生长因子（ING）候选肿瘤抑制因子家族的最后一个成员，它涉及多种细胞功能，包括细胞周期调控、细胞凋亡和染色质重塑。我们之前的研究表明，ING5 过表达可抑制肺癌的侵袭和上皮间质转化（EMT），但其具体机制尚不清楚。
采用 Western blot 检测 β-catenin 及其磷酸化水平和 EMT 相关蛋白的表达。免疫荧光染色观察 E-钙黏蛋白的表达。采用增殖和集落形成、划痕愈合、Transwell 迁移和侵袭实验研究癌细胞的增殖和侵袭能力。
ING5 过表达促进 β-catenin 在 Ser33/37 位的磷酸化，导致 β-catenin 蛋白水平降低。短发夹 RNA 介导的 ING5 敲低显著增加了 β-catenin 水平并抑制了 β-catenin S33/37 的磷酸化。WNT/β-catenin 抑制剂 XAV939 处理可抑制 ING5 敲低促进的肺癌 A549 细胞的增殖、集落形成、迁移和侵袭，同时增加了 β-catenin S33/37 的磷酸化，降低了 β-catenin 水平。XAV939 还削弱了 ING5 敲低诱导的 EMT，表现为上皮标志物 E-钙黏蛋白表达上调，间充质标志物 N-钙黏蛋白表达下调，以及 EMT 相关转录因子，包括 Snail、Slug、Twist 和 Smad3 的表达下调。此外，XAV939 还能抑制 IL-6/STAT3 和 PI3K/Akt 信号通路的激活。
ING5 通过抑制 WNT/β-catenin 通路抑制肺癌侵袭和 EMT。
