Lv Huiqing, Zhang Zhongmin, Wu Xiaoyu, Wang Yaoxia, Li Chenglin, Gong Weihong, Gui Liang, Wang Xin
Department of Hyperbaric Oxygen, Lin Yi People's Hospital, Lin Yi, China.
Department of Oncology, Lin Yi People's Hospital, Lin Yi, China.
PLoS One. 2016 Jan 4;11(1):e0145195. doi: 10.1371/journal.pone.0145195. eCollection 2016.
Hepatocellular carcinoma (HCC) remains a global health threat. The search for novel anti-HCC agents is urgent. In the current study, we synthesized a liposomal C8 ceramide, and analyzed its anti-tumor activity in pre-clinical HCC models. The liposomal C8 (ceramide) potently inhibited HCC cell (HepG2, SMMC-7721 and Huh-7 lines) survival and proliferation, more efficiently than free C8 ceramide. Yet, non-cancerous HL7702 human hepatocytes were resistant to the liposomal C8 treatment. Liposomal C8 activated caspase-dependent apoptosis in HCC cells, and HCC cytotoxicity by liposomal C8 was significantly attenuated with co-treatment of caspase inhibitors. At the molecular level, we showed that liposomal C8 activated ASK1 (apoptosis signal-regulating kinase 1)-JNK (Jun N-terminal protein kinase) signaling in HCC cells. On the other hand, JNK pharmacological inhibition or dominant negative mutation, as well as ASK1 shRNA-knockdown remarkably inhibited liposomal C8-induced apoptosis in HCC cells. Further studies showed that liposomal C8 inhibited AKT-mTOR (mammalian target of rapamycin) activation in HCC cells. Restoring AKT-mTOR activation by introducing a constitutively-active AKT alleviated HepG2 cytotoxicity by liposomal C8. In vivo, intravenous (i.v.) injection of liposomal C8 significantly inhibited HepG2 xenograft growth in severe combined immuno-deficient (SCID) mice, and mice survival was significantly improved. These preclinical results suggest that liposomal C8 could be further studied as a valuable anti-HCC agent.
肝细胞癌（HCC）仍然是全球健康的一大威胁。寻找新型抗HCC药物迫在眉睫。在本研究中，我们合成了一种脂质体C8神经酰胺，并在临床前HCC模型中分析了其抗肿瘤活性。脂质体C8（神经酰胺）能有效抑制HCC细胞（HepG2、SMMC - 7721和Huh - 7细胞系）的存活和增殖，其效果比游离C8神经酰胺更显著。然而，非癌性HL7702人肝细胞对脂质体C8处理具有抗性。脂质体C8可激活HCC细胞中依赖半胱天冬酶的凋亡，并且半胱天冬酶抑制剂的共同处理可显著减弱脂质体C8对HCC的细胞毒性。在分子水平上，我们发现脂质体C8可激活HCC细胞中的ASK1（凋亡信号调节激酶1）-JNK（Jun N端蛋白激酶）信号通路。另一方面，JNK的药理学抑制或显性负性突变，以及ASK1的短发夹RNA敲低均显著抑制了脂质体C8诱导的HCC细胞凋亡。进一步研究表明，脂质体C8可抑制HCC细胞中AKT - mTOR（雷帕霉素哺乳动物靶蛋白）的激活。通过引入组成型活性AKT来恢复AKT - mTOR的激活可减轻脂质体C8对HepG2的细胞毒性。在体内，静脉注射脂质体C8可显著抑制严重联合免疫缺陷（SCID）小鼠体内HepG2异种移植瘤的生长，并显著提高小鼠的存活率。这些临床前结果表明，脂质体C8有望作为一种有价值的抗HCC药物进行进一步研究。
