SPOP对肾细胞癌生物学特性的影响及其分子机制的研究

Renal cell carcinoma is one of the most common tumor of urinary system. The incidence of renal cell carcinoma increased significantly in recent years in China. There is no effective treatment for local advanced or metastatic renal cell carcinoma. SPOP is identified as an adaptor for the E3 ligase Cullin3, and related with tumorigenesis and aggression. Published studies demonstrated SPOP was overexpressed in human renal cell carcinoma tissue. Our previous research indicated the relative expression of SPOP in Caki-2 cells, a more aggressive renal cell carcinoma cell line is higher than that of Caki-1 cells. However, the overall effect of SPOP on biological features of renal cell carcinoma remains unclear. The present project tries to clarify the regulatory mechanism of SPOP on biological features of renal cell carcinoma through target drug sensitivity assay, in vivo and in vitro experiments. The effect of SPOP on cell proliferation, immigration and invasion will be identified by in vitro cell experiment. The studies of xenograft tumor model were performed to investigate the regulatory mechanism of tumorigenesis and metastasis in vivo. The correlation of SPOP expression level in renal cell carcinoma specimen and sensitivity of target drugs/ resistance of interferon will be determined by clinical data analysis. The important significance of our project is to clarify the overall molecular mechanism of tumorigenesis and aggression and target drug tolerance/interferon resistance in renal cell carcinoma.

肾癌是泌尿系统常见肿瘤之一 ，近年来国内的发病率显著增加。目前对局部进展期和转移性肾癌尚无满意的治疗方法。SPOP是泛素连接酶E3的配体，与多种肿瘤的发生发展密切相关，研究证实SPOP在肾癌组织中呈过表达状态。我们前期研究显示：SPOP在高侵袭性肾癌细胞系Caki-2中的表达显著高于Caki-1细胞，但其对肾癌细胞整体生物学特性的影响尚不十分清楚。本项目拟从体内，体外和靶向药物敏感性三方面研究SPOP对肾癌生物学特性的分子调控机制。体外实验研究SPOP对细胞增殖，迁移和侵袭的影响以及对PI3K/Akt /mTOR和JAK-STAT等信号通路的分子调控机制；体内动物实验阐明SPOP在体内调控肿瘤增殖和转移的机制；结合临床资料阐明SPOP在肾癌标本中的表达与靶向药物/干扰素疗效的相关性。本研究对阐明肾癌发生发展和侵袭的分子机制以及肾癌靶向药物耐药/干扰素抵抗的分子机制具有十分重要的意义。

SPOP是Cul3泛素连接酶的底物适配器，通过促进底物的泛素化和降解在实体肿瘤中发挥重要作用。有限的研究表明SPOP在人肾细胞癌(RCC)组织中过表达，可能参与了肾癌的发生发展。然而，SPOP在RCC中的确切作用尚不清楚，有待进一步阐明。本项目通过细胞学、药物敏感性实验及免疫组化染色阐述了SPOP对肾癌细胞的恶性生物学行为具有一定的抑制作用，与以往研究结果显著不同，本研究发现SPOP的表达在一定程度上抑制了肾癌细胞的增殖、迁移和侵袭，增加细胞凋亡。此外，SPOP过表达提高了肾癌细胞的药物敏感性、增殖抑制率及总凋亡率。SPOP在肾癌组织中的低表达率，在癌旁组织及正常肾组织中的高表达率也进一步提示SPOP在肾癌中具有潜在抑癌作用。本项目在分子水平内对SPOP在肾癌中的作用进行了一定的深入研究,并初步探索了可能与SPOP发生相互作用的潜在底物。研究成果已在国内期刊发表相关论文2篇，一篇在投SCI文章。本项目成果丰富了肾癌靶向治疗的分子理论，为下一步深入临床研究和应用提供了一定的理论依据和实验基础。