Department of Gastroenterology, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
Cancer. 2010 Mar 1;116(5):1252-63. doi: 10.1002/cncr.24814.
XIAP-associated factor 1 (XAF1) antagonizes the anticaspase activity of XIAP (X-linked inhibitor of apoptosis) and functions as a tumor suppressor in colon cancer. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is known as a potential anticancer agent. In this study, the synergistic effect of XAF1 and TRAIL on colon cancer growth was investigated.
Adeno-XAF1 virus was generated and purified. Cell apoptosis was detected by flow-cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Protein expression of the different genes was determined by Western blot analysis. Tumorigenesis and tumor growth were assessed in subcutaneous nude mouse xenograft experiments.
Stable overexpression of XAF1-sensitized colon cancer cells to TRAIL-induced apoptosis significantly increased the activity of caspase 3, 7, 8, and 9; released cytochrome c; and down-regulated XIAP, survivin, and c-IAP-2. The restoration of XAF1 expression mediated by adenovirus (adeno-XAF1) directly induced apoptosis, and synergized TRAIL-induced apoptosis in colon cancer cells. Ex vivo transduction of adeno-XAF1 suppressed colon cancer formation in vivo. Furthermore, adeno-XAF1 treatment of mice significantly inhibited tumor growth, strongly enhanced TRAIL-induced apoptosis and antitumor activity in colon cancer xenograft models in vivo, and markedly prolonged the survival. Notably, the combined treatment with adeno-XAF1 and TRAIL completely eradicated the established tumors without detectable toxicity in normal tissue.
The combined restoration of XAF1 expression and TRAIL treatment may be a potent strategy for colon cancer therapy.
XIAP 相关因子 1（XAF1）拮抗 XIAP（凋亡抑制蛋白 X 连锁）的抗胱天蛋白酶活性，并在结肠癌中作为肿瘤抑制因子发挥作用。肿瘤坏死因子相关凋亡诱导配体（TRAIL）被认为是一种潜在的抗癌剂。在这项研究中，研究了 XAF1 和 TRAIL 对结肠癌生长的协同作用。
生成并纯化腺病毒-XAF1。通过流式细胞术和末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记测定检测细胞凋亡。通过 Western blot 分析测定不同基因的蛋白表达。在皮下裸鼠异种移植实验中评估肿瘤发生和肿瘤生长。
稳定过表达 XAF1 使结肠癌细胞对 TRAIL 诱导的凋亡敏感，显著增加了 caspase 3、7、8 和 9 的活性；释放细胞色素 c；并下调 XIAP、存活素和 c-IAP-2。腺病毒（adeno-XAF1）介导的 XAF1 表达恢复直接诱导了凋亡，并与结肠癌细胞中 TRAIL 诱导的凋亡协同作用。体内腺病毒转导 adeno-XAF1 抑制了结肠癌的形成。此外，腺病毒 adeno-XAF1 处理显著抑制了肿瘤生长，强烈增强了 TRAIL 诱导的结肠癌异种移植模型中的凋亡和抗肿瘤活性，并显著延长了生存期。值得注意的是，联合使用 adeno-XAF1 和 TRAIL 完全消除了已建立的肿瘤，而在正常组织中没有检测到毒性。
联合恢复 XAF1 表达和 TRAIL 治疗可能是结肠癌治疗的有效策略。
