骨肉瘤外泌体miR-21通过调控PI3K/AKT通路促进骨肉瘤细胞侵袭及血管生成北大核心

目的:探讨骨肉瘤外泌体miR-21对骨肉瘤细胞侵袭能力的影响以及对血管生成的作用机制。方法:qRT-PCR法检测人正常骨细胞hFOB1.19与人骨肉瘤细胞系U2OS、Saos-2和MG-63中miR-21的表达,并确定表达水平高的作为本研究细胞系。通过差速离心提取细胞外泌体,并采用透射电镜和Western blot鉴定该外泌体;通过免疫荧光染色检测外泌体能否进入人血管内皮细胞(human vascular endothelial cells,HUVEC)发挥作用;利用脂质体2000分别转染Control、miR-21-inhibitor以及miR-21-mimic,通过Transwell实验检测外泌体miR-21对U2OS细胞侵袭能力的影响,并进一步采用Western blot检测miR-21对血管相关蛋白VEGF、HIF-1α以及PI3K/AKT通路蛋白的影响。结果:人骨肉瘤细胞系Saos-2、MG-63和U2OS中miR-21均呈高表达。透射电镜观察到,外泌体呈圆形或椭圆形泡状结构,且其特征蛋白CD9、CD63和CD81蛋白在外泌体中较U2OS细胞中表达高。免疫荧光结果显示,U2OS外泌体能成功进入HUVEC细胞中发挥作用。Transwell实验结果表明,外泌体miR-21可以促进骨肉瘤细胞侵袭。Western blot结果表明,与Control组相比,miR-21-mimic组血管生成蛋白VEGF和HIF-1α表达水平显著上升,PI3K/AKT通路蛋白表达水平亦显著升高,差异均有统计学意义(P<0.05)。结论:U2OS外泌体miR-21可以促进骨肉瘤细胞侵袭和血管生成,其作用机制可能与miR-21进入细胞激活PI3K/AKT信号通路有关。     

外泌体携带的miR-142-3p通过靶向COX-2抑制骨肉瘤细胞的增殖和侵袭

目的:探讨骨肉瘤组织中miR-142-3p是否可以通过靶向COX-2来抑制肿瘤细胞增殖和侵袭能力,并且验证携带miR-142-3p的外泌体是否可以抑制骨肉瘤细胞生长。方法:检测骨肉瘤癌组织及癌旁组织中miR-142-3p和COX-2 mRNA的表达。用双荧光素酶报告基因实验验证miR-142-3p与COX-2 3' UTR的靶向关系。构建过表达miR-142-3p及COX-2细胞系,检测细胞的增殖及侵袭能力。用携带miR-142-3p的外泌体处理肿瘤细胞,检测细胞的增殖及侵袭能力。对携带miR-142-3p的外泌体进行体内抑瘤实验。结果:较癌旁组织而言,miR-142-3p在癌组织中显著低表达（P＜0.05）,而COX-2在癌组织中显著高表达（P＜0.05）,且COX-2是miR-142-3p的靶标。过表达miR-142-3p的细胞增殖及侵袭能力降低（P＜0.001）。体外增殖实验及小鼠体内移植瘤模型表明,携带miR-142-3p的外泌体可以在小鼠体内外抑制骨肉瘤细胞的增殖（P＜0.001）。结论:携带miR-142-3p的外泌体可通过抑制COX-2的表达来抑制骨肉瘤细胞的生长,因此,携带miR-142-3p的外泌体可能发展成为一种治疗骨肉瘤的潜在策略。     

骨肉瘤血清外泌体整合素β4水平检测及其与临床病理特征和肺转移的相关性

目的:通过检测骨肉瘤患者血清外泌体整合素β4水平,分析其与临床病理特征的相关性,为骨肉瘤肺转移的预测提供理论依据.方法:收集骨肉瘤患者外周血,将患者分为术前组、术后无肺转移组及术后肺转移组,通过超高速离心法分离、提取外泌体,透射电镜对外泌体的形态及大小进行鉴定,同时应用流式细胞术鉴定外泌体特征性分子标志CD63、CD8...     

前列腺癌LNCaP-AI+F细胞外泌体促进基质细胞WPMY-1 功能活化

[摘要] 目的：探讨前列腺癌外泌体对基质细胞WPMY-1 迁移和侵袭能力的影响及其作用机制。方法：超速离心法提取前列腺癌LNCaP-AI+F细胞上清中的外泌体,电镜观察外泌体的典型形态结构,Zetaview 检测外泌体的粒径分布,Wb鉴定外泌体标志蛋白及其他相关蛋白。将WPMY-1 细胞与前列腺癌外泌体（40 μg/ml）共孵育后,激光共聚焦显微镜观察WPMY-1 细胞对PKH67 标记的外泌体的摄取情况,Transwell 实验检测WPMY-1 细胞迁移和侵袭能力,qPCR检测IL-8、PDGFB和MMP9 等三种肿瘤相关成纤维细胞(cancer-associated fibroblast,CAF)分子表达水平,Wb检测EGFR和ERK1/2 蛋白磷酸化水平。结果：电镜下可观察到典型茶托状外泌体结构,外泌体粒径分布集中在100 nm左右,其标志蛋白CD63 和ALIX的表达证实了所提取颗粒为外泌体。此外,外泌体还表达EGFR、HER2 和SRC 等三种与前列腺癌进展相关的蛋白。WPMY-1 细胞与外泌体共孵育后,共聚焦显微镜下可看到该细胞摄取大量外泌体,明显促进WPMY-1 细胞的迁移和侵袭能力（均P<0.01）;与对照组比较,外泌体（40 μg/ml）处理后WPMY-1 IL-8、PDGFB及MMP9 表达水平增高（P<0.05 或P<0.01）;且外泌体促进了WPMY-1 细胞EGFR和ERK1/2 的磷酸化（P<0.01）。结论：前列腺癌细胞可通过外泌体作用于基质细胞WPMY-1,使其高表达多种CAF 相关分子,促进EGFR 和ERK1/2 的磷酸化,增强其迁移和侵袭能力。     

骨肉瘤源外泌体通过Tim-3诱导巨噬细胞M2极化并促进MG63细胞的 转移

目的：探究骨肉瘤来源的外泌体对肿瘤相关巨噬细胞分化的影响及其具体作用机制。方法：收集2018年3月至 2019年10年于川北医学院附属医院骨科及小儿外科行骨肉瘤切除术、病理诊断明确的18例原发性骨肉瘤患者的肿瘤组织及癌 旁组织,Western blotting实验检测Tim-3的表达水平;分离骨肉瘤MG63细胞外泌体（MG63-Exo）,并采用透射电镜及纳米粒径分 析进行鉴定,双荧光染色法验证其是否能够被巨噬细胞吞噬,利用qPCR检测MG63-Exo对巨噬细胞分化及IL-10、TGF-β、VEGF 表达的影响,应用Transwell侵袭和迁移实验及Western blotting检测MG63-Exo所诱导分化的巨噬细胞对MG63细胞迁移及侵袭 及EMT相关蛋白表达的影响;应用CRISPR/Cas9技术敲除MG63细胞中的Tim-3,Western blotting实验检测MG63-Exo中Tim-3 表达,再次应用qPCR、Transwell及Western blotting实验检测来源于敲除Tim-3的MG63外泌体对巨噬细胞分化及其处理后的巨 噬细胞对MG63的迁移、侵袭、EMT相关蛋白表达的影响;最后利用骨肉瘤肺转移小鼠模型验证上述不同来源的外泌体对骨肉瘤 肺转移的影响。结果：透射电镜及纳米粒径分析结果证实成功分离了MG63-Exo,荧光共聚焦显微观察结果显示其能够被巨噬 细胞吞噬。与对照组相比,MG63-Exo能够显著促进巨噬细胞的M2型分化（P<0.05）;与对照组相比, 经MG63-Exo诱导的M2巨 噬细胞能够显著促进骨肉瘤细胞的迁移、侵袭与EMT能力（均P<0.05）;应用CRISPR/Cas9技术敲除Tim-3后的MG63细胞中 Tim-3 mRNA及蛋白表达均显著降低（P<0.05）, 且Tim-3能够以外泌体的形式转移至巨噬细胞中; 与MG63-Exo共培养的巨噬细 胞相比,来源于Tim-3敲除细胞的MG63-Exo能显著抑制巨噬细胞的M2型分化（P<0.05）;相比与经MG63-Exo诱导的巨噬细胞 进行共培养的MG63细胞,Tim-3敲除的MG63-Exo诱导的巨噬细胞能显著抑制肿瘤细胞的迁移、侵袭与EMT及促进肿瘤肺转移 （均P<0.05）。结论：骨肉瘤来源的外泌体通过Tim-3诱导巨噬细胞的M2极化并促进肿瘤的侵袭及转移能力。     

食管鳞癌细胞外泌体中miR-130a对血管新生的作用及其机制

目的 探讨食管鳞癌细胞外泌体中的miR-130a对血管新生的作用及其机制.方法 提取食管上皮细胞HEEC、食管鳞癌细胞TE-13和Eca-109所分泌的外泌体及转染miR-130a mimic、miR-130a inhibitor及其阴性对照(NC)后的Eca-109细胞外泌体,并与人脐静脉血管内皮细胞HUVEC共孵育...     

外泌体检测在骨肿瘤诊疗中的意义

体液活检是近些年恶性肿瘤研究的热点。液态活检包括游离DNA（circulating free DNA,cfDNA）检测、循环肿瘤细胞（circulating tumor cells,CTCs）检测、细胞外泌体检测。对于间叶组织来源的骨肉瘤和尤文肉瘤而言,由于肿瘤异质性明显同时又缺乏经典的肿瘤标志物,以细胞标志物为手段的循环肿瘤细胞检测在骨肉瘤和尤文肉瘤等间叶组织来源恶性肿瘤的预后监测中的作用受到明显制约。体液中存在的肿瘤细胞外泌体因携带其”母体”肿瘤细胞的部分功能性蛋白及基因,并作为肿瘤液态活检的一种新途径,受到大家的广泛关注,其也可能在骨肉瘤和尤文肉瘤的发病、诊断和治疗中发挥着重要作用。本文旨在对外泌体的特性、在恶性肿瘤进展中发挥的重要作用及应用前景进行综述,以期为实现其在临床中的推广应用提供参考。      

卵巢癌SKOV3细胞外泌体分泌水平及其对顺铂敏感性的影响

目的:探究卵巢癌SKOV3细胞外泌体分泌水平与其顺铂敏感性的关系。方法:用超速离心法提取卵巢癌细胞外泌体,透射电镜与纳米粒径示踪分析(NTA)外泌体形态与粒径大小,Western blot检测外泌体表面标志性蛋白水平,电感耦合等离子体质谱计检测外泌体中顺铂含量,CCK-8检测细胞增殖情况,流式细胞凋亡术检测细胞凋亡情况。结果:外泌体纳米粒径示踪分析检测示:卵巢癌细胞外泌体释放水平与外泌体抑制剂GW4869水平呈浓度依赖性,随着抑制剂浓度的增加,卵巢癌外泌体分泌减少。CCK-8实验与流式凋亡检测实验结果显示:随着卵巢癌细胞外泌体释放水平的降低,其对于顺铂敏感性增强。电感耦合等离子体质谱计检测示:外泌体能够携带一部分顺铂外排,并且随着外泌体释放水平的降低,外泌体外排的顺铂含量也逐渐降低,而细胞内顺铂含量逐渐增加,从而对顺铂敏感性增强。结论:卵巢癌SKOV3细胞可通过外泌体外排顺铂,抑制外泌体释放可增强肿瘤细胞的顺铂敏感性。     

外泌体在肿瘤微环境中调控肿瘤转移机制的研究进展

外泌体是具有双层膜结构的细胞外囊泡,其直径在40～160nm之间.在生理或病理条件下,大多数细胞都可以释放外泌体到微环境中,肿瘤微环境中的细胞和肿瘤细胞本身都可以分泌大量的外泌体.外泌体通过携带蛋白质、脂质和核酸等物质,在细胞间进行物质交换和信息交流从而促进肿瘤转移.肿瘤微环境是由肿瘤细胞、免疫细胞、成纤维细胞及细胞外...     

不同细胞来源外泌体对肿瘤微环境的重塑作用

囊泡转运是细胞间沟通的重要方式。随着蛋白质组学、代谢组学、RNA组学等多组学联合研究的发展和进步,研究人员发现外泌体是细胞间通讯的重要信号转导媒介和介质。外泌体携带大量生物活性分子,对细胞生物学功能的发挥具有重要的调控作用,影响肿瘤细胞的特性。越来越多的证据表明,外泌体的功能与其来源的细胞及其内含物成分密切相关。肿瘤来源外泌体以自分泌和旁分泌的方式诱导癌细胞和基质细胞生理功能和代谢状态的改变,基质细胞来源外泌体参与建立、支持和营养肿瘤细胞的肿瘤微环境,并且不同免疫细胞来源外泌体可能呈现截然相反的功能。本文就不同细胞来源外泌体在肿瘤微环境中的作用和机制进行综述,为外泌体在肿瘤诊断、治疗及预后评估中的应用提供参考。     

MicroRNA-100 shuttled by mesenchymal stem cell-derived exosomes suppresses in vitro angiogenesis through modulating the mTOR/HIF-1α/VEGF signaling axis in breast cancer cells

Background

Human mesenchymal stem cells (MSCs) have been shown to be involved in the formation and modulation of tumor stroma and in interacting with tumor cells, partly through their secretome. Exosomes are nano-sized intraluminal multi-vesicular bodies secreted by most types of cells and have been found to mediate intercellular communication through the transfer of genetic information via coding and non-coding RNAs to recipient cells. Since exosomes are considered as protective and enriched sources of shuttle microRNAs (miRNAs), we hypothesized that exosomal transfer of miRNAs from MSCs may affect tumor cell behavior, particularly angiogenesis.

Methods

Exosomes derived from MSCs were isolated and characterized by scanning electron microscopy analyses, dynamic light scattering measurements, and Western blotting. Fold changes in miR-100 expression levels were calculated in exosomes and their corresponding donor cells by qRT-PCR. The effects of exosomal transfer of miR-100 from MSCs were assessed by qRT-PCR and Western blotting of the mTOR/HIF-1α/VEGF signaling axis in breast cancer cells. The quantification of secreted VEGF protein was determined by enzyme-linked immunosorbent assay. The putative paracrine effects of MSC-derived exosomes on tumor angiogenesis were explored by in vitro angiogenesis assays including endothelial cell proliferation, migration and tube formation assays.

Results

We found that MSC-derived exosomes induce a significant and dose-dependent decrease in the expression and secretion of vascular endothelial growth factor (VEGF) through modulating the mTOR/HIF-1α signaling axis in breast cancer-derived cells. We also found that miR-100 is enriched in MSC-derived exosomes and that its transfer to breast cancer-derived cells is associated with the down-regulation of VEGF in a time-dependent manner. The putative role of exosomal miR-100 transfer in regulating VEGF expression was substantiated by the ability of anti-miR-100 to rescue the inhibitory effects of MSC-derived exosomes on the expression of VEGF in breast cancer-derived cells. In addition, we found that down-regulation of VEGF mediated by MSC-derived exosomes can affect the vascular behavior of endothelial cells in vitro.

Conclusions

Overall, our findings suggest that exosomal transfer of miR-100 may be a novel mechanism underlying the paracrine effects of MSC-derived exosomes and may provide a means by which these vesicles can modulate vascular responses within the microenvironment of breast cancer cells.

     

Exosomal miR-1228 From Cancer-Associated Fibroblasts Promotes Cell Migration and Invasion of Osteosarcoma by Directly Targeting SCAI

Cancer-associated fibroblasts (CAFs) play a predominant role in regulating tumor progression. Understanding how CAFs communicate with osteosarcoma is crucial for developing novel approaches for osteosarcoma therapy. Exosomes are able to transmit messages between cells. In this study, we demonstrated that CAFs transfer exosomes to osteosarcoma cells, which promotes osteosarcoma cell migration and invasion. Using a miRNA microarray analysis, we identified 13 miRNAs that are significantly increased in exosomes derived from cancer-associated fibroblasts (CAFs) and corresponding paracancer fibroblasts (PAFs). In vitro studies further validated that the levels of microRNA-1228 (miR-1228) were increased in CAFs, its secreted exosomes, and in recipient osteosarcoma cells, which can downregulate endogenous SCAI mRNA and protein level in osteosarcoma. Furthermore, our findings demonstrate that SCAI was downregulated in osteosarcoma tissues. Taken together, this study provides evidence that CAF exosomal miR-1228 is able to promote osteosarcoma invasion and migration by targeting SCAI, which may represent a critical therapeutic target for osteosarcoma treatment.     

过表达血管生成抑制蛋白1对人结直肠癌细胞恶性生物学行为的影响

目的:探讨过表达血管生成抑制蛋白1(vasohibin-1,VASH1)对人结直肠癌细胞恶性生物学行为的影响.方法:包装慢病毒并感染人结直肠癌SW680、SW620细胞以构建过表达VASH1的细胞系,以未经感染的细胞为对照;qPCR实验和WB实验检测VASH1的过表达效果,小管形成实验、CCK-8实验、软琼脂克隆形成实...     

Circulating exosomal noncoding RNAs as prognostic biomarkers in human hepatocellular carcinoma

Exosomal noncoding RNAs (ncRNAs) have unique expression profiles reflecting the characteristics of a tumor, and their role in tumor progression and metastasis is emerging. However, the significance of circulating exosomal ncRNAs in the prognosis of hepatocellular carcinoma (HCC) remains to be elucidated. We therefore determined the prognostic significance of circulating exosomal ncRNAs (miRNA-21 and lncRNA-ATB) for human HCC. This prospective study enrolled 79 HCC patients between October 2014 and September 2015. Exosomes were extracted from serum samples using the ExoQuick Exosome Precipitation Solution. To validate the isolation of the exosomes from serum, immunoblotting for exosome markers and characterization of nanoparticle using NanoSight were performed. NcRNAs were isolated from exosomes using the miRNeasy serum/plasma micro kit. Both circulating exosomal miRNA-21 and lncRNA-ATB were related to TNM stage and other prognostic factors, including the T stage and portal vein thrombosis. Multivariate analysis using the Cox regression test identified that both higher miRNA-21 and higher lncRNA-ATB were independent predictors of mortality and disease progression, along with larger tumor size and higher C-reactive protein (all p < 0.05). The overall survival and progression-free survival were significantly lower in patients with higher circulating levels of exosomal miRNA-21 (≥0.09) and lncRNA-ATB (≥0.0016) (log-rank test: p < 0.05). In conclusion, our study has provided strong evidence that circulating exosomal ncRNAs (miRNA-21 and lncRNA-ATB) are novel prognostic markers and therapeutic targets for HCC.     

Exosomes as potential diagnosis and treatment for liver cancer

BACKGROUNDLiver cancer is the fourth most significant cause of cancer-related death. Lack of early diagnosis strategy and a scarcity of efficient therapy constitute the main reasons for its lethality. Exosomes, which contain various bioactive molecules, are characterized by high biocompatibility, low immunogenicity, and high transport efficiency. As a result, exosomes have become a research hotspot and present significant potential for cancer diagnosis biomarkers, biotherapeutics, therapy targets, drug carriers and therapeutic agents.AIMTo explore the potential of exosomes in the diagnosis and treatment of liver cancer.METHODSWe conducted a systematic literature search via PubMed and Web of Science. The following keywords were used: "exosomal biomarkers", "exosomal therapy", "exosomal therapy", and "liver cancer" or "HCC". The duplicate data were deleted by EndNote software. Literature search focused on full-texts and references of each article were carefully checked. One author (Xiao-Cui Wei) screened the literature that met the following inclusion criteria: (1) Detection of exosomes or their contents in clinical samples (body fluid or tissue); or (2) Exosomes served as drug carriers or therapeutic factors. Two authors (Xiao-Cui Wei and Li-Juan Liu) independently reviewed all retained literature and analyzed the information.RESULTSA total of 1295 studies were identified using the systematic literature search. Of these, 835 duplicate studies were removed. A further 402 irrelevant studies were excluded due to being irrelevant, including other diseases, review articles, the literature containing neither clinical samples nor animal experiments, exosome-independent studies, methods for detecting exosomes, or articles in Chinese. Finally, 58 published papers were retained and analyzed in the study. It showed a list of potential exosomal biomarkers that were upregulated in the blood samples of patients with liver cancer. Those downregulated in exosomes might serve as possible biotherapeutics. Some exosomes derived from cells in vitro were used for cytology or animal experiments to explore the mechanism of these exosome contents in disease. These contents might serve as potential targets for liver cancer. Additionally, we also discussed that exosomes serve as drug carriers or therapeutic factors.CONCLUSIONExosomes might serve as potential biomarkers or therapeutic biotargets in liver cancer and have the potential to act as drug carriers and self-treatment factors for liver cancer patients.     

miR-449b-5p通过靶向Cyclin E2抑制卵巢癌细胞生长和细胞周期进展

目的:探讨miR-449b-5p对卵巢癌细胞生长的作用和机制.方法:选取2018年6月至2020年6月于四川省人民医院妇产科接受手术的20例卵巢癌患者的癌组织和癌旁组织,以及正常卵巢上皮细胞系HOSEpiC和6种人宫颈癌细胞系SKOV3、ES-2、OVCAR-3、HO8910、CaOV-3和 A2780,用 qPCR ...     

Systemic presence and tumor-growth promoting effect of ovarian carcinoma released exosomes

Exosomes are membrane vesicles that are released from many different cell types. Tumor derived-exosomes play a role in immune suppression. We hypothesized that in ovarian carcinoma patients exosomes initially produced at the local abdominal site may become systemic. We examined paired samples of ascites and blood from ovarian carcinoma patients for the presence of exosomes. We also studied the requirements for exosomal uptake by immune cells, the role of phosphatidyl-serine (PS) as uptake signal and the effect of exosome application on tumor growth. We used exosomes from ovarian carcinoma cell lines, malignant ascites and sera from ovarian carcinoma patients isolated by ultracentrifugation. PS-displayed by exosomes was detected by Anexin-V-FITC staining of latex beads adsorbed exosomes. For uptake experiments, labeled exosomes were exposed to cells in the presence or absence of cold Annexin-V as competitor. Uptake was examined by fluorescent microscopy and cytofluorographic analysis. Effects of exosomes on tumor growth were studied using SKOV3ip ovarian carcinoma cells in CD1 nu/nu mice. We found that malignant ascites-derived exosomes cargo tumor progression related proteins such as L1CAM, CD24, ADAM10, and EMMPRIN. We observed that exosomes become systemic via the blood stream. Uptake of ovarian carcinoma exosomes by NK cells was found to require PS at the exosomal surface but the presence of PS was not sufficient. Application of malignant ascites-derived exosomes to tumor bearing mice resulted in augmented tumor growth. Exosomes from the serum of tumor patients could be isolated from only one ml of blood and this analysis could serve for diagnostic purposes. We propose that tumor-derived exosomes could play a role in tumor progression.     

Induction of myeloid‐derived suppressor cells by tumor exosomes

Myeloid‐derived suppressor cells (MDSCs) promote tumor progression. The mechanisms of MDSC development during tumor growth remain unknown. Tumor exosomes (T‐exosomes) have been implicated to play a role in immune regulation, however the role of exosomes in the induction of MDSCs is unclear. Our previous work demonstrated that exosomes isolated from tumor cells are taken up by bone marrow myeloid cells. Here, we extend those findings showing that exosomes isolated from T‐exosomes switch the differentiation pathway of these myeloid cells to the MDSC pathway (CD11b⁺Gr‐1⁺). The resulting cells exhibit MDSC phenotypic and functional characteristics including promotion of tumor growth. Furthermore, we demonstrated that in vivo MDSC mediated promotion of tumor progression is dependent on T‐exosome prostaglandin E2 (PGE2) and TGF‐β molecules. T‐exosomes can induce the accumulation of MDSCs expressing Cox2, IL‐6, VEGF, and arginase‐1. Antibodies against exosomal PGE2 and TGF‐β block the activity of these exosomes on MDSC induction and therefore attenuate MDSC‐mediated tumor‐promoting ability. Exosomal PGE2 and TGF‐β are enriched in T‐exosomes when compared with exosomes isolated from the supernatants of cultured tumor cells (C‐exosomes). The tumor microenvironment has an effect on the potency of T‐exosome mediated induction of MDSCs by regulating the sorting and the amount of exosomal PGE2 and TGF‐β available. Together, these findings lend themselves to developing specific targetable therapeutic strategies to reduce or eliminate MDSC‐induced immunosuppression and hence enhance host antitumor immunotherapy efficacy. © 2008 Wiley‐Liss, Inc.     

High‐mobility group box‐1 contributes tumor angiogenesis under interleukin‐8 mediation during gastric cancer progression

Many soluble factors are involved in tumor angiogenesis. Thus, it is valuable to identify novel soluble factors for effective control of tumor angiogenesis in gastric cancer (GC). We investigated the role of extracellular high‐mobility group box‐1 (HMGB1) and its associated soluble factors in the tumor angiogenesis of GC. Clinically, we measured serum levels of HMGB1 and GC‐associated cytokines/chemokines using GC serum samples (n = 120), and calculated microvessel density (MVD) by CD34 immunostaining using human GC tissues (n = 27). Then we analyzed the correlation of serum HMGB1 levels with MVD or that with cytokine/chemokine levels by linear regression. As in vitro angiogenesis assay for HMGB1, HUVEC migration and capillary tube formation assay were carried out using different histological types of human GC cells (N87 and KATOIII). CD34‐positive microvessels were detected from early GC, but MVD increased according to GC stages, and were closely correlated with serum HMGB1 levels (R = 0.608, P = 0.01). The HUVECs cultured in conditioned media derived from rhHMGB1‐treated or HMGB1‐TF GC cells showed remarkably enhanced migration and tube formation activities. These effects were abrogated by anti‐HMGB1 antibody or HMGB1 siRNA in both N87 and KATOIII cells (all P < 0.05). Among tested cytokines/chemokines, interleukin‐8 (IL‐8) was the most remarkable cytokine correlated with serum HMGB1 (P < 0.001), and enhanced HUVEC migration and tube formation activities by rhHMGB1 or HMGB1‐TF were significantly reversed by IL‐8 inhibition. These results indicate overexpressed HMGB1 contributes to tumor angiogenesis through IL‐8 mediation, and combined targeting of HMGB1 and IL‐8 can control tumor angiogenesis in GC.