Zhou Chunxian, Chen Zhengrong, Lu Xingsheng, Wu Hao, Yang Qunying, Xu Dongfeng
Department of Interventional Radiology, WuJiang Hospital Affiliated to Nantong University, No. 169 Park Road, Songling Town, WuJiang, Suzhou, 215200, China.
Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215000, China.
Tumour Biol. 2016 Mar;37(3):3135-44. doi: 10.1007/s13277-015-4134-3. Epub 2015 Oct 1.
The colorectal cancer (CRC) is one leading contributor of cancer-related mortality worldwide. The search for effective anti-CRC agents is valuable. In the current study, we showed that icaritin (ICT), an active natural ingredient from the Chinese plant Epimedium, potently inhibited proliferation and survival of established (HT-29, HCT-116, DLD-1, and SW-620) and primary (patient-derived) CRC cells. Significantly, ICT mainly induced necrosis, but not apoptosis, in CRC cells. The necrosis inhibitor necrostatin-1 attenuated ICT-mediated cytotoxicity in CRC cells. We showed that ICT treatment in CRC cells induced mitochondrial permeability transition pore (mPTP) opening, which was evidenced by mitochondrial membrane potential (MMP) decrease and mitochondrial adenine nucleotide translocator-1 (ANT-1)-cyclophilin-D (CyPD) association. On the other hand, mPTP blockers, including sanglifehrin A, cyclosporin A, and bongkrekic acid, as well as siRNA-mediated knockdown of mPTP component (CyPD or ANT-1), significantly alleviated ICT-mediated cytotoxicity against CRC cells. We suggested that Jun-N-terminal kinase (JNK) activation by ICT mediated mPTP opening and subsequent CRC cell necrosis. JNK pharmacological inhibition, dominant negative mutation, or shRNA downregulation suppressed ICT-induced MMP reduction and subsequent HT-29 cell necrosis. In vivo, oral gavage of ICT dramatically inhibited HT-29 xenograft growth in nude mice. The in vivo activity by ICT was largely attenuated by co-administration with the mPTP blocker CsA. Collectively, our results showed that ICT exerts potent inhibitory effect against CRC cells in vitro and in vivo. JNK-dependent mPTP necrosis pathway could be key mechanism responsible for ICT's actions.
结直肠癌（CRC）是全球癌症相关死亡的主要原因之一。寻找有效的抗CRC药物具有重要价值。在本研究中，我们发现淫羊藿素（ICT），一种从中国植物淫羊藿中提取的活性天然成分，能有效抑制已建立的（HT-29、HCT-116、DLD-1和SW-620）及原发性（患者来源）CRC细胞的增殖和存活。值得注意的是，ICT主要诱导CRC细胞坏死，而非凋亡。坏死抑制剂Necrostatin-1可减弱ICT介导的CRC细胞毒性。我们发现，ICT处理CRC细胞可诱导线粒体通透性转换孔（mPTP）开放，这可通过线粒体膜电位（MMP）降低以及线粒体腺嘌呤核苷酸转位酶-1（ANT-1）与亲环蛋白D（CyPD）的结合得到证实。另一方面，mPTP阻滞剂，包括桑吉瓦霉素A、环孢素A和邦克酸，以及siRNA介导的mPTP组分（CyPD或ANT-1）敲低，可显著减轻ICT介导的对CRC细胞的细胞毒性。我们认为，ICT激活Jun氨基末端激酶（JNK）介导mPTP开放及随后的CRC细胞坏死。JNK的药理学抑制、显性负性突变或shRNA下调可抑制ICT诱导的MMP降低及随后的HT-29细胞坏死。在体内，口服ICT可显著抑制裸鼠体内HT-29异种移植瘤的生长。与mPTP阻滞剂环孢素A共同给药可大大减弱ICT的体内活性。总体而言，我们的结果表明，ICT在体外和体内均对CRC细胞具有强大的抑制作用。JNK依赖性mPTP坏死途径可能是ICT发挥作用的关键机制。
