Gao Ming, Yeh Pei Yen, Lu Yen-Shen, Hsu Chih-Hung, Chen Kuen-Feng, Lee Wei-Chung, Feng Wen-Chi, Chen Ching-Shih, Kuo Min-Liang, Cheng Ann-Lii
Institute of Toxicology, National Taiwan University, Taipei 10016, Taiwan, Republic of China.
Cancer Res. 2008 Nov 15;68(22):9348-57. doi: 10.1158/0008-5472.CAN-08-1642.
Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of cancer death worldwide. Systemic treatments for HCC have been largely unsuccessful. OSU-03012 is a derivative of celecoxib with anticancer activity. The mechanism of action is presumably 3-phosphoinositide-dependent kinase 1 (PDK1) inhibition. This study investigated the potential of OSU-03012 as a treatment for HCC. OSU-03012 inhibited cell growth of Huh7, Hep3B, and HepG2 cells with IC(50) below 1 mumol/L. In Huh7 cells, OSU-03012 did not suppress PDK1 or AKT activity. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay and flow cytometry analysis indicated that OSU-03012 did not induce cellular apoptosis. Instead, morphologic studies by light and electron microscopy, as well as special biological staining with monodansylcadaverine, acridine orange, and microtubule-associated protein 1 light chain 3, revealed OSU-03012-induced autophagy of Huh7 cells. This OSU-03012-induced autophagy was inhibited by 3-methyladenine. Moreover, reactive oxygen species (ROS) accumulation was detected after OSU-03012 treatment. Blocking ROS accumulation with ROS scavengers inhibited autophagy formation, indicating that ROS accumulation and subsequent autophagy formation might be a major mechanism of action of OSU-03012. Daily oral treatment of BALB/c nude mice with OSU-03012 suppressed the growth of Huh7 tumor xenografts. Electron microscopic observation indicated that OSU-03012 induced autophagy in vivo. Together, our results show that OSU-03012 induces autophagic cell death but not apoptosis in HCC and that the autophagy-inducing activity is at least partially related to ROS accumulation.
肝细胞癌（HCC）是全球第五大常见癌症，也是癌症死亡的第三大主要原因。HCC的全身治疗在很大程度上并不成功。OSU-03012是塞来昔布的一种具有抗癌活性的衍生物。其作用机制可能是抑制3-磷酸肌醇依赖性激酶1（PDK1）。本研究调查了OSU-03012作为HCC治疗药物的潜力。OSU-03012抑制Huh7、Hep3B和HepG2细胞的生长，其半数抑制浓度（IC50）低于1μmol/L。在Huh7细胞中，OSU-03012不抑制PDK1或AKT活性。末端脱氧核苷酸转移酶介导的dUTP缺口末端标记试验和流式细胞术分析表明，OSU-03012不诱导细胞凋亡。相反，光镜和电镜的形态学研究，以及用单丹磺酰尸胺、吖啶橙和微管相关蛋白1轻链3进行的特殊生物染色，显示OSU-03012诱导Huh7细胞自噬。这种由OSU-03012诱导的自噬被3-甲基腺嘌呤抑制。此外，在OSU-03012处理后检测到活性氧（ROS）积累。用ROS清除剂阻断ROS积累可抑制自噬形成，表明ROS积累及随后的自噬形成可能是OSU-03012的主要作用机制。用OSU-03012每日口服治疗BALB/c裸鼠可抑制Huh7肿瘤异种移植瘤的生长。电镜观察表明，OSU-03012在体内诱导自噬。总之，我们的结果表明，OSU-03012在HCC中诱导自噬性细胞死亡而非凋亡，且自噬诱导活性至少部分与ROS积累有关。
