Tian Aiping, Wilson George S, Lie Stefanus, Wu Guang, Hu Zenan, Hebbard Lionel, Duan Wei, George Jacob, Qiao Liang
First Clinical Medical School and the Department of Gastroenterology and Hepatology of the First Hospital of Lanzhou University, Lanzhou 730000, China.
Storr Liver Unit, University of Sydney, Westmead Millennium Institute, Westmead, NSW 2145, Australia.
Cancer Lett. 2014 Sep 1;351(2):232-41. doi: 10.1016/j.canlet.2014.06.006. Epub 2014 Jun 27.
Inhibitor of Apoptosis Proteins (IAPs) are key regulators of apoptosis in hepatocellular carcinoma (HCC) and their expression is negatively correlated with patient survival. LCL161 is a small molecule inhibitor of IAPs that has potent antitumour activity in a range of solid tumours. In HCC, response to LCL161 therapy has shown to be mediated by Bcl-2 expression. In this study, we aim to determine whether LCL161 has any therapeutic potential in HCC. Protein expression was determined by Western blot. Cell proliferation was determined by Cell Proliferation ELISA and BrdU colorimetric assays. Apoptosis was determined by Annexin V assay. Cell cycle analysis was performed by staining cells with propidium iodide and analysed in a FACScan. Automated Cell Counter and phase contrast microscopy were used to determine the cell viability. We have found that LCL161 targets (cIAP1, cIAP2 and XIAP) were up-regulated in HCC tumours. Both high Bcl-2 expressing HuH7 cells and low Bcl-2 expressing SNU423 cells showed strong resistance to LCL161 therapy with significant effects on both apoptosis and cell viability only evident at LCL161 concentrations of ⩾100μM. At these doses there was significant inhibition of IAP targets, however there was also significant inhibition of off-target proteins including pERK and pJNK suggesting apoptosis caused by drug toxicity. However, when used in combination with paclitaxel in HuH7 and SNU423 cells, LCL161 had significant antiproliferative effects at doses as low as 2μM and this was independent of Bcl-2 expression. Thus, LCL161 may be a useful agent in combination with paclitaxel to treat liver tumours.
凋亡抑制蛋白（IAPs）是肝细胞癌（HCC）凋亡的关键调节因子，其表达与患者生存率呈负相关。LCL161是一种IAPs小分子抑制剂，在一系列实体瘤中具有强大的抗肿瘤活性。在HCC中，对LCL161治疗的反应已显示由Bcl-2表达介导。在本研究中，我们旨在确定LCL161在HCC中是否具有任何治疗潜力。通过蛋白质印迹法测定蛋白质表达。通过细胞增殖ELISA和BrdU比色法测定细胞增殖。通过膜联蛋白V测定法测定细胞凋亡。通过用碘化丙啶对细胞进行染色并在FACScan中进行分析来进行细胞周期分析。使用自动细胞计数器和相差显微镜来确定细胞活力。我们发现LCL161的靶标（cIAP1、cIAP2和XIAP）在HCC肿瘤中上调。高表达Bcl-2的HuH7细胞和低表达Bcl-2的SNU423细胞对LCL161治疗均表现出强烈抗性，仅在LCL161浓度≥100μM时对细胞凋亡和细胞活力有显著影响。在这些剂量下，IAP靶标受到显著抑制，但包括pERK和pJNK在内的脱靶蛋白也受到显著抑制，提示药物毒性导致细胞凋亡。然而，当与紫杉醇联合用于HuH7和SNU423细胞时，LCL161在低至2μM的剂量下具有显著的抗增殖作用，且这与Bcl-2表达无关。因此，LCL161可能是与紫杉醇联合治疗肝肿瘤的有用药物。
