Chang Te-Sheng, Chen Chi-Long, Wu Yu-Chih, Liu Jun-Jen, Kuo Yung Che, Lee Kam-Fai, Lin Sin-Yi, Lin Sey-En, Tung Shui-Yi, Kuo Liang-Mou, Tsai Ying-Huang, Huang Yen-Hua
Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan.
PLoS One. 2016 Feb 26;11(2):e0149897. doi: 10.1371/journal.pone.0149897. eCollection 2016.
The expression of cancer stemness is believed to reduce the efficacy of current therapies against hepatocellular carcinoma (HCC). Understanding of the stemness-regulating signaling pathways incurred by a specific etiology can facilitate the development of novel targets for individualized therapy against HCC. Niche environments, such as virus-induced inflammation, may play a crucial role. However, the mechanisms linking inflammation and stemness expression in HCC remain unclear. Here we demonstrated the distinct role of inflammatory mediators in expressions of stemness-related properties involving the pluripotent octamer-binding transcription factor 4 (OCT4) in cell migration and drug resistance of hepatitis B virus-related HCC (HBV-HCC). We observed positive immunorecognition for macrophage chemoattractant protein 1 (MCP-1)/CD68 and OCT4/NANOG in HBV-HCC tissues. The inflammation-conditioned medium (inflamed-CM) generated by lipopolysaccharide-stimulated U937 human leukemia cells significantly increased the mRNA and protein levels of OCT4/NANOG preferentially in HBV-active (HBV+HBsAg+) HCC cells. The inflamed-CM also increased the side population (SP) cell percentage, green fluorescent protein (GFP)-positive cell population, and luciferase activity of OCT4 promoter-GFP/luciferase in HBV-active HCC cells. Furthermore, the inflamed-CM upregulated the expressions of insulin-like growth factor-I (IGF-I)/IGF-I receptor (IGF-IR) and activated IGF-IR/Akt signaling in HBV-HCC. The IGF-IR phosphorylation inhibitor picropodophyllin (PPP) suppressed inflamed-CM-induced OCT4 and NANOG levels in HBV+HBsAg+ Hep3B cells. Forced expression of OCT4 significantly increased the secondary sphere formation and cell migration, and reduced susceptibility of HBV-HCC cells to cisplatin, bleomycin, and doxorubicin. Taking together, our results show that niche inflammatory mediators play critical roles in inducing the expression of stemness-related properties involving IGF-IR activation, and the upregulation of OCT4 contributes to cancer migration and drug resistance of HBV-HCC cells. Findings in this paper would provide potential targets for a therapeutic strategy targeting on inflammatory environment for HBV-HCC.
癌症干性的表达被认为会降低当前针对肝细胞癌（HCC）治疗的疗效。了解特定病因引发的干性调节信号通路有助于开发针对HCC个体化治疗的新靶点。生态位环境，如病毒诱导的炎症，可能起关键作用。然而，HCC中炎症与干性表达之间的联系机制仍不清楚。在此，我们证明了炎症介质在涉及多能性八聚体结合转录因子4（OCT4）的干性相关特性表达中的独特作用，这些特性包括乙型肝炎病毒相关HCC（HBV-HCC）细胞迁移和耐药性。我们观察到HBV-HCC组织中巨噬细胞趋化蛋白1（MCP-1）/CD68和OCT4/NANOG呈阳性免疫反应。脂多糖刺激的U937人白血病细胞产生的炎症条件培养基（炎症-CM）显著优先增加了HBV活跃（HBV+HBsAg+）HCC细胞中OCT4/NANOG的mRNA和蛋白水平。炎症-CM还增加了HBV活跃HCC细胞中的侧群（SP）细胞百分比、绿色荧光蛋白（GFP）阳性细胞群体以及OCT4启动子-GFP/荧光素酶的荧光素酶活性。此外，炎症-CM上调了HBV-HCC中胰岛素样生长因子-I（IGF-I）/IGF-I受体（IGF-IR）的表达并激活了IGF-IR/Akt信号通路。IGF-IR磷酸化抑制剂鬼臼苦素（PPP）抑制了炎症-CM诱导的HBV+HBsAg+Hep3B细胞中OCT4和NANOG的水平。OCT4的强制表达显著增加了二次球体形成和细胞迁移，并降低了HBV-HCC细胞对顺铂、博来霉素和阿霉素的敏感性。综上所述，我们的结果表明生态位炎症介质在诱导涉及IGF-IR激活的干性相关特性表达中起关键作用，并表明OCT4的上调促成了HBV-HCC细胞的癌症迁移和耐药性。本文的研究结果将为针对HBV-HCC炎症环境的治疗策略提供潜在靶点。
