肺岩宁方介导外泌体HOTAIR调控TGF-β/PTHrP/RANKL通路抑制肺癌骨转移的机制研究

Lung cancer is one of the difficulties and emphases in clinical treatment. Previous studies showed that osteolytic bone metastasis is governed by TGF-β/PTHrP/RANKL signaling pathway through regulating osteoblast differentiation, and Feiyanning decoction can effectively suppress this pathway to inhibit lung cancer bone metastasis, but its molecular mechanism has not been fully clarified. Our previous studies also determined that lncRNA HOTAIR within exosomes of the peripheral blood of lung cancer bone metastasis patients as well as the medium of lung cancer cells were highly expressed and contributed to the cell proliferation, migration and invasion of lung cancer. In addition, the ability of si-HOTAIR cell-drived exosomes to promote invasion and metastasis of lung cancer cells was significantly weakened, TGF-β and its downstream genes were also significantly down-regulated. Therefore, we speculate that exosomal HOTAIR may regulates activation of osteoclasts by activating TGF-β signaling pathway and promote lung cancer bone metastasis. This project is to investigate the regulatory mechanism of HOTAIR/TGF-β/PTHrP signal axis in lung cancer bone metastasis around the exosomal HOTAIR, and the mechanism of Feiyanning decoction on bone metastasis through the above signal pathway. This project can provide theoretical basis for targeted therapy on lung cancer in clinical application.

肺癌骨转移是目前临床治疗的重难点之一。前期研究发现TGF-β/PTHrP/RANKL是溶骨性骨转移的关键信号通路，通过刺激破骨细胞分化发挥骨质溶解作用，而肺岩宁方能有效阻滞该通路从而抑制肺癌骨转移，但其分子机制尚不清楚。课题组研究发现长链非编码RNA-HOTAIR在肺癌骨转移患者外周血和肺癌细胞外泌体中均呈高表达，细胞实验证实外泌体HOTAIR可以促进肺癌细胞的侵袭和迁移，此外，si-HOTAIR细胞来源的外泌体促进肺癌细胞侵袭转移能力明显减弱，并能显著下调TGF-β及其下游因子。因此，我们推测外泌体HOTAIR可能通过激活TGF-β信号通路，调节破骨细胞活化以促进肺癌骨转移。本课题拟围绕外泌体HOTAIR为研究对象，研究HOTAIR/TGF-β/PTHrP信号轴调控肺癌骨转移的分子机制，并深入探讨肺岩宁方通过上述信号通路逆转肺癌骨转移的作用机理，从而为开展肺癌临床靶向治疗提供理论依据。

肺癌骨转移的具体机制尚不清楚，而肺癌细胞来源的外泌体在这一过程中的作用备受关注。在本次研究中，我们发现A549细胞来源的外泌体在破骨细胞分化和骨转移中是一个重要的胞外囊泡，而A549细胞的外泌体中HOTAIR的表达高于正常肺纤维细胞。此外，我们发现富含HOTAIR的外泌体在体外和体内促进破骨细胞的分化。我们进一步探讨其机制，发现A549-Exosomal HOTAIR通过靶向TGF-β/PTHrP/RANKL通路促进骨吸收。因此，本课题揭示了外泌体HOTAIR通过调节TGF-β信号通路，促进破骨细胞活化，介导肺癌骨转移的机制，以及肺岩宁方阻断外泌体HOTAIR运送，调节HOTAIR-TGF-β-PTHrP-RANKL生物信息传递的机制，初步阐明了肺岩宁方逆转肺癌骨转移的作用途径。此外，我们还新发现了外泌体miR-328能够促进骨吸收，并新增了外泌体miR-328的相关实验研究，本课题发表了3篇项目资助的相关研究论文，其中SCI3篇，培养硕士研究生2名，协助培养博士生1名。