Heat shock protein 70 surface-positive tumor exosomes stimulate migratory and cytolytic activity of natural killer cells
Heat shock protein 70 surface-positive tumor exosomes stimulate migratory and cytolytic activity of natural killer cells
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DOI：
10.1158/0008-5472.can-04-3804
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发表时间：
2005-06-15
期刊：
影响因子：
11.2
通讯作者：
Multhoff, G
中科院分区：
文献类型：
--
作者：
Gastpar, R;Gehrmann, M;Multhoff, G
人类胰腺（Colo-/Colo+）和结肠（CX-/CX+）癌亚系积极释放清洁剂溶性膜泡，它们在质膜上呈递热休克蛋白70 (Hsp70)/Bag-4的能力不同。漂浮特性、乙酰胆碱酯酶活性和蛋白质组成特征表明它们是外泌体。rabb -4的富集记录了它们从早期核内体到质膜的细胞内运输途径。溶解后，在肿瘤来源的外泌体中检测到相当数量的细胞质蛋白，包括微管蛋白、Hsp70、Hsc70和Bag-4，但没有er驻留Grp94和钙连蛋白。而外泌体表面只有Colo+/CX+衍生外泌体呈Hsp70膜阳性，而Colo-/CX-衍生外泌体无Hsp70膜阳性。因此，在激活标记的细胞表面密度上调的同时，表面阳性的Hsp70/Bag-4外泌体选择性地刺激了自然杀伤（NK）细胞的迁移和Hsp70反应性，而其阴性对应体和肿瘤细胞裂解物则没有。此外，外泌体介导的NK细胞裂解活性可被hsp70特异性抗体阻断。正如已经表明的TKD刺激，与Hsp70表面阳性外泌体预孵育的NK细胞通过颗粒酶B的释放启动肿瘤细胞凋亡。总之，我们的数据提供了NK细胞中Hsp70反应性如何被肿瘤来源的外泌体诱导的解释。
Detergent-soluble membrane vesicles are actively released by human pancreas (Colo-/Colo+) and colon (CX-/CX+) carcinoma sublines, differing in their capacity to present heat shock protein 70 (Hsp70)/Bag-4 on their plasma membranes. Floating properties, acetylcholine esterase activity, and protein composition characterized them as exosomes. An enrichment of Rab-4 documented their intracellular transport route from early endosomes to the plasma membrane. After solubilization, comparable amounts of cytosolic proteins, including tubulin, Hsp70, Hsc70, and Bag-4, but not ER-residing Grp94 and calnexin, were detectable in tumor-derived exosomes. However, with respect to the exosomal surface, only Colo+/CX+ but not Colo-/CX- derived exosomes were Hsp70 membrane positive. Therefore, concomitant with an up-regulated cell surface density of activation markers, migration and Hsp70 reactivity of natural killer (NK) cells was stimulated selectively by Hsp70/Bag-4 surface-positive exosomes, but not by their negative counterparts and tumor cell lysates. Moreover, the exosome-mediated lytic activity of NK cells was blockable by Hsp70-specific antibody. As already shown for TKD stimulation, NK cells preincubated with Hsp70 surface-positive exosomes initiated apoptosis in tumors through granzyme B release. In summary, our data provide an explanation how Hsp70 reactivity in NK cells is induced by tumor-derived exosomes.