Han Zewen, Li Qingxiang, Wang Yifei, Wang Lin, Li Xiaoxu, Ge Na, Wang Yixiang, Guo Chuanbin
Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, China.
Front Pharmacol. 2019 Jan 9;9:1544. doi: 10.3389/fphar.2018.01544. eCollection 2018.
Niclosamide is a traditional anti-tapeworm drug that exhibits potent anti-cancer activity. Our previous study showed that niclosamide induces cell cycle arrest in G1 phase. Nevertheless, the underlying mechanism remains unknown. The following study investigated the molecular mechanism through which niclosamide induced G1 arrest in head and neck squamous cell carcinoma (HNSCC) cell lines. The effect of niclosamide on human HNSCC cell line WSU-HN6 and CNE-2Z were analyzed using IncuCyte ZOOM assay, flow cytometry (FCM), real-time PCR and western blot. Luciferase assay was conducted to demonstrate the interaction between let-7d (a let-7 family member which functions as a tumor suppressor by regulating cell cycle) and 3'UTR of CDC34 mRNA. Xenografts tumor model was established to evaluate the niclosamide treatment efficacy . Briefly, an exposure to niclosamide treatment led to an increased let-7d expression and a decreased expression of cell cycle regulator CDC34, finally leading to G1 phase arrest. Moreover, an overexpression of let-7d induced G1 phase arrest and downregulated CDC34, while the knockdown of let-7d partially rescued the niclosamide-induced G1 phase arrest. Luciferase assay confirmed the direct inhibition of CDC34 through the targeting of let-7d. Furthermore, niclosamide markedly inhibited the xenografts growth through up-regulation of let-7d and down-regulation of CDC34. To sum up, our findings suggest that niclosamide induces cell cycle arrest in G1 phase in HNSCC through let-7d/CDC34 axis, which enriches the anti-cancer mechanism of niclosamide.
氯硝柳胺是一种传统的抗绦虫药物，具有强大的抗癌活性。我们之前的研究表明，氯硝柳胺可诱导细胞周期停滞于G1期。然而，其潜在机制仍不清楚。以下研究调查了氯硝柳胺在头颈部鳞状细胞癌（HNSCC）细胞系中诱导G1期停滞的分子机制。使用IncuCyte ZOOM分析、流式细胞术（FCM）、实时PCR和蛋白质印迹法分析了氯硝柳胺对人HNSCC细胞系WSU-HN6和CNE-2Z的影响。进行荧光素酶测定以证明let-7d（let-7家族成员，通过调节细胞周期发挥肿瘤抑制作用）与CDC34 mRNA的3'UTR之间的相互作用。建立异种移植肿瘤模型以评估氯硝柳胺的治疗效果。简而言之，氯硝柳胺处理导致let-7d表达增加，细胞周期调节因子CDC34表达降低，最终导致G1期停滞。此外，let-7d的过表达诱导G1期停滞并下调CDC34，而let-7d的敲低部分挽救了氯硝柳胺诱导的G1期停滞。荧光素酶测定证实了通过靶向let-7d对CDC34的直接抑制作用。此外，氯硝柳胺通过上调let-7d和下调CDC34显著抑制异种移植肿瘤的生长。综上所述，我们的研究结果表明，氯硝柳胺通过let-7d/CDC34轴在HNSCC中诱导细胞周期停滞于G1期，这丰富了氯硝柳胺的抗癌机制。
