miR-29b/STAT3/GATA3正反馈环路逆转TAM极化并抑制尤文肉瘤恶性表型的机制研究

Ewing sarcoma (ES) is a kind of primary bone tumor with great malignancy. Multiple tumor-associated macrophages (TAM) were reported to negatively related with tumor metastasis and recurrence. Thus, it is suggested to be a new way for ES therapy in the future. Considered the relationship between metastasis and TAM infiltration as the breakthrough point, we found and identified that miR-29b expression was closely related with the infiltration of TAM in the ES tissues. Interestingly, STAT3, which played a critical role in the regulation of macrophage polarization, was predicted to be a putative target gene of miR-29b. Moreover, through suppressing the expression of GATA3, overexpression of STAT3 suppressed the expression of miR-29b, which makes us to speculate that the feedback loop of miR-29b/STAT3/GATA3 might play an important role in the regulation of macrophage polarization and its-associated suppression on the malignant phenotype of ES. In this paper, we will further explore the effects of miR-29b on TAM-associated suppression on the malignant phenotype of ES, and further identify its influence on the macrophage polarization in ES cells and mice. Lastly, we will further verify whether miR-29b/STAT3/GATA3 loop was involved in the effects.

尤文肉瘤（ES）是高度恶性的原发骨肿瘤，肿瘤相关巨噬细胞（TAM）在局部微环境中的浸润与肿瘤转移和复发相关，因此改善微环境中TAM浸润是治愈ES的关键。课题小组以转移与TAM浸润的相关性为切入点，发现并验证miR-29b与尤文肉瘤TAM浸润密切相关，而参与M2型极化作用的STAT3是miR-29b的靶基因之一，后者能够通过抑制GATA3表达进一步反馈抑制miR-29b的转录，我们推测miR-29b/STAT3/GATA3环路能够逆转尤文肉瘤TAM极化并抑制ES恶性生物学表型。研究拟以miR-29b为研究对象，分别在ES细胞系及荷瘤裸鼠中考察miR-29b对TAM介导的尤文肉瘤恶性生物学表型的影响；另一方面通过研究miR-29b对体外单核细胞极化及其分泌细胞因子的作用，检测其对TAM极化及表型的影响，并验证miR-29b/STAT3/GATA3通路在该作用中的调控机制。

尤文肉瘤（ES）是高度恶性的原发骨肿瘤，肿瘤相关巨噬细胞（TAM）在局部微环境中的浸润与肿瘤转移和复发相关，因此改善微环境中TAM浸润是治愈ES的关键。本项目在以上研究基础上，通过分析转移与非转移肿瘤组织中TAM细胞浸润及共培养体系分析TAM是否参与尤文肉瘤细胞生物学功能的影响，并探讨其可能机制。通过实验证实：1）伴有转移病灶的尤文肉瘤肿瘤组织中TAM浸润比例增加；2）诱导后肿瘤相关巨噬细胞能够诱导肉瘤肿瘤细胞增殖、侵袭、迁移以及血管新生；3）伴有转移病灶的尤文肉瘤组织TAM细胞中miR-29b表达下降；4）恢复miR-29b表达能够逆转TAM对尤文肉瘤肿瘤细胞的促进作用；5）miR-29b能够靶向调控STAT3表达，而后者能够通过抑制GATA3表达而反向性调控miR-29b表达，两者之间均呈负相关；综上所述，miR-29b参与TAM细胞介导尤文肉瘤细胞生物学表型调控，而STAT3/GATA3通路可能参与其中的作用调控；以上的实验结果将为尤文肉瘤肿瘤的发生、发展体重新的理论基础，同时为尤文肉瘤的肿瘤生物治疗提供新的思路。