Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, People's Republic of China.
School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, 312 Anshanxi Road, Tianjin, 300193, People's Republic of China.
Apoptosis. 2019 Feb;24(1-2):33-45. doi: 10.1007/s10495-018-1497-0.
Combined oridonin (ORI), a natural and safe kaurene diterpenoid isolated from Rabdosia rubescens, and cetuximab (Cet), an anti-EGFR monoclonal antibody, have been reported to exert synergistic anti-tumor effects against laryngeal squamous cell carcinoma (LSCC) both in vitro and in vivo by our group. In the present study, we further found that ORI/Cet treatment not only resulted in apoptosis but also induced autophagy. AMPK/mTOR signaling pathway was found to be involved in the activation of autophagy in ORI/Cet-treated LSCC cells, which is independent of p53 status. Additionally, chromatin immunoprecipitation (ChIP) assay showed that ORI/Cet significantly increased the binding NF-κB family member p65 with the promotor of BECN 1, and p65-mediated up-regulation of BECN 1 caused by ORI/Cet is coupled to increased autophagy. On the other hand, we demonstrated that either Beclin 1 SiRNA or autophagy inhibitors could increase ORI/Cet induced-apoptosis, indicating that autophagy induced by combination of the two agents plays a cytoprotective role. Interestingly, 48 h after the combined treatment, autophagy began to decrease but apoptosis was significantly elevated. Our findings suggest that autophagy might be strongly associated with the antitumor efficacy of ORI/Cet, which may be beneficial to the clinical application of ORI/Cet in LSCC treatment.
联合冬凌草甲素（ORI）和西妥昔单抗（Cet）治疗喉鳞状细胞癌的协同抗肿瘤作用及其机制。冬凌草甲素（ORI）是一种从冬凌草中分离出来的天然、安全的贝壳杉烯二萜类化合物，西妥昔单抗（Cet）是一种抗 EGFR 的单克隆抗体。我们的研究小组之前报道过，ORI 和 Cet 联合应用在体外和体内均对喉鳞状细胞癌（LSCC）具有协同的抗肿瘤作用。在本研究中，我们进一步发现 ORI/Cet 治疗不仅导致细胞凋亡，还诱导了自噬。AMPK/mTOR 信号通路参与了 ORI/Cet 处理的 LSCC 细胞中自噬的激活，该通路的激活与 p53 状态无关。此外，染色质免疫沉淀（ChIP）实验表明，ORI/Cet 显著增加了 NF-κB 家族成员 p65 与 BECN1 启动子的结合，而 ORI/Cet 引起的 p65 介导的 BECN1 上调与自噬增加有关。另一方面，我们证明 Beclin 1 SiRNA 或自噬抑制剂可增加 ORI/Cet 诱导的细胞凋亡，表明这两种药物联合诱导的自噬发挥了细胞保护作用。有趣的是，联合处理 48 小时后，自噬开始减少，但细胞凋亡明显增加。我们的研究结果表明，自噬可能与 ORI/Cet 的抗肿瘤疗效密切相关，这可能有助于 ORI/Cet 在 LSCC 治疗中的临床应用。
