PICK1在骨肉瘤发展和转移中的作用及机制研究

The treatment of osteosarcoma (OS), especially those with metastasis, remains challenging. What’s more, the complexity of mechanisms underlying invasion and metastasis of osteosarcoma makes it difficult to obtain meaningful progress in patient survival. As one of the key regulators in oncogenesis, TGF-β signaling pathway is associated with the disease progression and lung metastasis of osteosarcoma in patients. Based on the interaction between PICK1 and TβRI, the type I receptor of TGF-β, PICK1 can regulate TGF-β signaling by modulating the intracellular transport of TβRI. However, whether PICK1 is involved in osteosarcoma, has not been reported. Results from our previous study indicate PICK1 protein is expressed in both bone tissue and osteosarcoma cells and can affect the expression level of TβRI in osteosarcoma cells, raising the possibility that PICK1 may have a role in regulating osteosarcoma via modulation of TGF-β signaling. Therefore, in this study, experiments of multiple levels, from molecular and cellular to animal and human, will be conducted to verify the relationship between PICK1 and tumor progression of osteosarcoma, investigate the effect of PICK1 on the viability and mobility of osteosarcoma cells, and interpret the way PICK1 regulates TGF-β signaling in osteosarcoma. In summary, by clarifying the role of PICK1 in osteosarcoma, this study may offer new insight into the complicated mechanisms of invasion and metastasis of osteosarcoma, thus providing novel therapeutic strategies for osteosarcoma patients.

骨肉瘤尤其伴有转移者是临床治疗中的难题，其发病和转移机制复杂且尚未完全阐明，使得治疗相关研究进展缓慢。TGF-β信号通路作为多种肿瘤的共同调控因素，对骨肉瘤的进展和肺转移具有重要影响。PICK1可通过与TGF-β受体TβRI相互作用，调节TβRI的细胞内转运、影响TGF-β信号通路活性，但PICK1是否对骨肉瘤具有调节作用尚无文献报道。我们的前期研究显示，PICK1在骨组织和骨肉瘤细胞中也存在表达，且可影响骨肉瘤细胞中的TβRI蛋白水平。据此我们提出假说：PICK1可通过TβRI调节TGF-β信号通路活性，参与对骨肉瘤发展和转移的调控。本项目拟从分子、细胞、动物以及临床回顾性研究等多个层次明确PICK1与骨肉瘤进展的关系，阐明PICK1对骨肉瘤细胞增殖和转移的影响，探讨PICK1对骨肉瘤TGF-β信号的调节作用。本研究将从PICK1这个新视点深化对骨肉瘤的认识，并为骨肉瘤的治疗提供新的思路

PICK1在乳腺癌、前列腺癌等多种肿瘤组织中存在表达异常，可能通过与TGF-β受体和Arp2/3复合物等分子的相互作用参与肿瘤的发展和转移，但其具体作用及机制仍存争议。此外，PICK1是否对骨肉瘤也有调节作用，尚缺乏相关研究。本课题从PICK1与TβRI受体的相互作用着手，探索PICK1对骨肉瘤TGF-β信号的调节作用，阐述PICK1对骨肉瘤发展和转移的影响。通过检测小鼠骨组织样本，证实在正常骨组织中可检测到PICK1与TβRI蛋白，且其蛋白水平可能与骨骼生长发育相关。通过检测不同来源骨肉瘤细胞，证明PICK1蛋白在骨肉瘤细胞中存在表达，且在部分细胞中与TβRI共定位。在骨肉瘤细胞中过表达PICK1可增加TβRI蛋白水平，与文献报道不同，提示在骨肉瘤中PICK1对TGF-β信号通路的调节机制可能与在乳腺癌等肿瘤中有所差异。利用含shRNA慢病毒，我们构建了对照、PICK1敲减和TβRI敲减三组骨肉瘤细胞，并发现PICK1敲减可降低骨肉瘤细胞K7M2的内源TβRI和SMAD3蛋白水平，并抑制TβRI的膜表达。通过Real-time PCR分析，我们发现PICK1敲减可降低TGF-β信号通路靶基因ANGPTL4的mRNA水平。MTT实验显示，PICK1敲减可抑制体外培养骨肉瘤细胞的增殖。综合上述结果，本研究为PICK１在骨肉瘤中的作用和对骨肉瘤发展和转移的调节机制提供了新的认识，同时也为探索骨肉瘤的治疗提供了新的靶点。