BAP31在多种肿瘤组织中高表达，促进肿瘤增殖与转移。我们发现BAP31过表达胃癌细胞MKN-45-B31外泌体可以促进内皮细胞增殖、迁移与血管生成；高通量测序MKN-45-B31外泌体microRNA表达谱，发现BAP31可以显著上调miR-21的表达水平，其被报道能够影响肿瘤转移前微环境，促进肿瘤血管生成。我们推测：过表达BAP31的肿瘤细胞通过上调外泌体miR-21的表达，促进转移癌细胞血管生成。在前期研究中我们以BAP31为抗原，从噬菌体抗体库中筛选获得特异性抑制外泌体miR-21表达的抗体F12。本项目将探索F12引起的外泌体miR-21表达抑制对胃癌细胞转移的影响。系统阐明F12经外泌体microRNA途径影响肿瘤转移前微环境及血管生成的分子机制。该研究将为癌症的治疗提供新的可能药物靶点和理论依据，也为拓展胞内抗体技术在癌症治疗领域的应用提供重要的探索思路。

BAP31 is highly expressed in many kinds of tumors and promotes the proliferation and metastasis of tumors. We found that exosome from BAP31 overexpressing gastric cancer cells MKN-45-B31 can promote endothelial cell proliferation, migration and angiogenesis; High-throughput sequencing of MKN-45-B31 exosome microRNA expression profiles showed that BAP31 can significantly up-regulate the expression of miR-21, which has been reported to affect the pre-metastasis microenvironment and promote tumor angiogenesis. We speculate that BAP31 overexpressing cancer cells can promote angiogenesis of metastatic cancer cells by up-regulating the expression of exosome microRNA-21. In previous studies, BAP31 was used as an antigen to screen F12 from a phage antibody library, which specifically inhibited the expression of exosome microRNA-21. This project will explore the effect of F12-induced inhibition of the expression of exosome microRNA-21 on the metastasis of gastric cancer cells and elucidate the molecular mechanism of F12 influencing microenvironment and angiogenesis through exosome microRNA . This study will provide new possible drug targets and theoretical basis for cancer treatment, and also provide important exploration ideas for expanding the application of intracellular antibody technology in the field of cancer treatment.