College of Life Sciences, Wuhan University, Wuhan, 430072, China.
Cancer Chemother Pharmacol. 2012 Mar;69(3):799-805. doi: 10.1007/s00280-011-1763-0. Epub 2011 Oct 29.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent due to its selective cytotoxicity to transformed cells. However, most human hepatocellular carcinomas (HCC) develop resistance to TRAIL. Thus, there is an urgent need to investigate the molecular targets and the underlying mechanisms that may be involved in overriding the resistance of tumor cells to TRAIL.
Cell viability analysis was performed in HCC cells after treatment with TRAIL and/or ABT-263. Flow cytometry was used to assess apoptosis. The expression of caspases and members of the Bcl-2 family was examined through immunoblot analysis. Finally, the viability of cancer cells transfected with a plasmid containing HBx (hepatitis B virus X protein) following treatment with TRAIL was also measured.
In this study, we demonstrate that ABT-263, a potent and orally bioavailable inhibitor of the Bcl-2 family, was able to reverse the resistance of hepatocarcinoma cell lines to TRAIL-induced apoptosis, while sparing normal liver cells. The molecular mechanism of the reversal in resistance may be attributed to the inhibition by ABT-263 of anti-apoptosis proteins of the Bcl-2 family. In addition, we determined that HBx was able to sensitize TRAIL-resistant hepatocarcinoma Huh7 cells.
These findings provide a novel insight into the clinical application of TRAIL-induced apoptosis of HCC cells.
肿瘤坏死因子相关凋亡诱导配体（TRAIL）因其对转化细胞的选择性细胞毒性而成为一种很有前途的抗癌药物。然而，大多数人肝癌（HCC）对 TRAIL 产生耐药性。因此，迫切需要研究可能涉及克服肿瘤细胞对 TRAIL 耐药性的分子靶标和潜在机制。
用 TRAIL 和/或 ABT-263 处理 HCC 细胞后，进行细胞活力分析。通过流式细胞术评估细胞凋亡。通过免疫印迹分析检测半胱天冬酶和 Bcl-2 家族成员的表达。最后，还测量了转染含有 HBx（乙型肝炎病毒 X 蛋白）质粒的癌细胞在 TRAIL 处理后的活力。
在这项研究中，我们证明了 ABT-263，一种有效的、口服生物利用的 Bcl-2 家族抑制剂，能够逆转肝癌细胞系对 TRAIL 诱导的细胞凋亡的耐药性，同时保留正常的肝细胞。耐药性逆转的分子机制可能归因于 ABT-263 抑制了 Bcl-2 家族的抗凋亡蛋白。此外，我们确定 HBx 能够使 TRAIL 耐药的肝癌 Huh7 细胞敏感。
这些发现为 TRAIL 诱导 HCC 细胞凋亡的临床应用提供了新的见解。
