DNA-PKcs通过调节Rho/ROCK信号通路参与骨肉瘤转移的研究

Osteosarcoma is featured with high incidence of metastasis. Metastasis is the main cause of death and the 5-year survival rate is 20%-30% for patients with metastasis. Hence, it is meaningful to research the mechanisms of formation and development of osteosarcoma metastasis in order to improve therapy and decrease metastasis rate. We have demonstrated that DNA-PKcs was overexpressed in osteosarcoma and the positive rate of DNA-PKcs was higher in patients with metastasis. DNA-PKcs was involved in migration and invasion of osteosarcoma cells and expression of ROCK2 which played an important role in tumor metastasis. These results provide theoretical evidence for investigation about the involvement of DNA-PKcs in osteosarcoma metastasis. We intend to examine the changes of cell motility in vitro, metastasis formation in vivo and activity of Rho/ROCK signal pathway after intervention of DNA-PKcs expression or function, to research the relationship between DNA-PKcs and osteosarcoma metastasis and the effect of the Rho/ROCK signal pathway. The purpose of the research is to explore the effect of DNA-PKcs on osteosarcoma metastasis and molecular mechanisms.

骨肉瘤具有较高的转移发生率，远处转移是造成患者死亡的主要原因，发生转移患者5年生存率仅为20%-30%。因此，研究骨肉瘤转移发生和发展的机制，对改进治疗方法、降低转移发生率具有重要意义。本课题组前期研究发现：DNA依赖性蛋白激酶催化亚单位（DNA-PKcs）在骨肉瘤中高表达，且在转移患者中的阳性表达率明显增高；另外，DNA-PKcs影响骨肉瘤细胞体外迁移、侵袭能力和在肿瘤转移中发挥重要作用的ROCK2的表达。以上发现为研究DNA-PKcs参与骨肉瘤转移提供了理论依据。本课题拟干预DNA-PKcs表达或功能后，检测骨肉瘤细胞体外运动能力、体内转移病灶形成、Rho/ROCK信号通路的变化，研究DNA-PKcs与骨肉瘤转移之间的关系以及Rho/ROCK信号通路在其中的的作用，旨在探讨DNA-PKcs在骨肉瘤转移中的作用及分子机制。

骨肉瘤(OS)的特点是高度倾向于发展的远处转移。DNA依赖的蛋白激酶催化亚基(DNA-PKcs)在细胞能中发挥着不同的作用，但DNA-PKcs在骨肉瘤转移中的参与尚不清楚。本研究旨在探讨DNA-PKcs在OS转移中的作用及其机制。在本研究中，DNA-PKcs抑制显著降低了体外OS细胞系的迁移和侵袭能力。DNA-PKcs的下调显著降低了基质金属蛋白酶2 (MMP2)和磷酸肌球蛋白轻链2 (p-MLC2)的表达和RhoA/ROCK2通路的活性。此外，ROCK2缺失还会影响骨肉瘤细胞的迁移和侵袭，以及MMP2和p-MLC2的表达。与没有DNA-PKcs缺失的细胞相比，DNA-PKcs缺失的MNNG/HOS细胞在非肥胖糖尿病/严重联合免疫缺陷(NOD/SCID)小鼠中导致更少和更小的转移病灶。提示DNA-PKcs通过RhoA/ROCK2途径参与MMP2和p-MLC2的表达，从而促进OS转移。本研究首次报道了DNA-PKcs与骨肉瘤转移的联系，为骨肉瘤靶向DNA-PKcs抗转移治疗提供了理论依据。..