Exosomes expressing carbonic anhydrase 9 promote angiogenesis
Exosomes expressing carbonic anhydrase 9 promote angiogenesis
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DOI：
10.1016/j.bbrc.2017.08.107
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发表时间：
2017-10-21
影响因子：
3.1
通讯作者：
Ito, Masafumi
中科院分区：
文献类型：
--
作者：
Horie, Kengo;Kawakami, Kyojiro;Ito, Masafumi
细胞分泌的外泌体或微泡被认为在肿瘤微环境中起重要作用。碳酸酐酶9（CA 9）是由低氧诱导因子1（HIF 1）在低氧条件下诱导的，在包括肾细胞癌（RCC）在内的多种癌症中过表达。我们检测了几种肾癌细胞系中CA 9的表达水平，发现OSRC-2细胞中CA 9的基础水平远高于Caki-1、KMRC-1和786-O细胞。与细胞内表达水平一致，在通过超离心从OSRC-2细胞分离的外来体中大量检测到CA 9。OSRC-2和786- 0外来体的密度梯度离心证实了CA 9与外来体标志物的共存。在缺氧和用CoCl 2（缺氧模拟剂）处理后，所有细胞系的外来体中的CA 9水平增加。为了检查CA 9外泌体对血管生成的影响，我们产生了表达CA 9的稳定转染的HEK 293细胞。免疫细胞化学染色显示CA 9外泌体被人脐静脉内皮细胞（HUVEC）摄取。使用HUVEC的体外血管生成测定显示，CA 9外泌体促进迁移和管形成。最后，在HUVEC中用CA 9外泌体处理增加MMP 2表达。总之，我们的结果表明，从缺氧RCC释放的CA 9外泌体可能会增强微环境中的血管生成，从而促进癌症进展。(C)2017爱思唯尔公司All rights reserved.
Exosomes or microvesicles that are secreted from cells are considered to play important roles in tumor microenvironment. Carbonic anhydrase 9 (CA9), which is induced by hypoxia-inducible factor 1 (HIF1) in response to hypoxia, is overexpressed in many types of cancer including renal cell carcinoma (RCC). We examined the expression level of CA9 in several RCC cell lines and found that the basal level of CA9 was much higher in OSRC-2 cells than in Caki-1, KMRC-1 and 786-O cells. Consistent with the intracellular expression levels, CA9 was abundantly detected in exosomes isolated by ultracentrifugation from OSRC-2 cells. Density gradient centrifugation of OSRC-2 and 786-O exosomes confirmed the co-presence of CA9 with exosomal markers. Upon hypoxia and treatment with CoCl2, a hypoxia mimic agent, the CA9 level in exosomes was increased for all cell lines. In order to examine the effects of CA9 exosomes on angiogenesis, we generated stably transfected HEK293 cells expressing CA9. Immunocytochemical staining demonstrated the uptake of CA9 exosomes by human umbilical vein endothelial cells (HUVEC). In vitro angiogenesis assays using HUVEC revealed that CA9 exosomes promoted migration and tube formation. Lastly, MMP2 expression was increased by treatment with CA9 exosomes in HUVEC. Taken together, our results suggest the possibility that CA9 exosomes released from hypoxic RCC may enhance angiogenesis in microenvironment, thereby contributing to cancer progression. (C) 2017 Elsevier Inc. All rights reserved.