HAMLET (human α-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death
HAMLET (human α-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death
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DOI：
10.1002/ijc.24076
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发表时间：
2009-03-01
影响因子：
6.4
通讯作者：
Svanborg, Catharina
中科院分区：
文献类型：
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作者：
Aits, Sonja;Gustafsson, Lotta;Svanborg, Catharina
哈姆雷特是一种部分展开的a-乳清蛋白和油酸的复合物，能杀死多种肿瘤细胞。在这里，我们提出哈姆雷特引起肿瘤细胞的巨噬，这有助于它们的死亡。细胞死亡伴随着线粒体损伤，活性mTOR和HAMLET水平的降低引发了广泛的细胞质空泡化和双膜封闭囊泡的形成，这是巨噬的典型特征。此外，在转染LC3- gfp的细胞中，HAMLET使LC3- gfp从均匀（LC3- i）染色变为颗粒状（LC3- ii）染色，反映了巨噬过程中LC3易位的变化，而这种变化被巨噬抑制剂3-甲基腺嘌呤阻断。当溶酶体降解被抑制时，Western blot检测到HAMLET也引起LC3-II的积累，提示HAMLET引起自噬通量增加。为了确定巨噬是否导致细胞死亡，我们使用RNA干扰Beclin-1和Atg5。抑制Beclin-1和Atg5提高了哈姆雷特处理的肿瘤细胞的存活率，抑制了LC3-GFP颗粒染色的增加。结果表明，HAMLET可触发肿瘤细胞的巨噬，提示巨噬有助于哈姆雷特诱导的肿瘤细胞死亡。(c) 2008 Wiley-Liss, Inc。
HAMLET, a complex of partially unfolded a-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death. (c) 2008 Wiley-Liss, Inc.