Studies on effects of KLEIP on cancer-progression

点击翻译按钮获取中文摘要

Kelch-like ECT2-interacting protein (KLEIP) is a member of the kelch-related actin-binding proteins and was originally isolated as a binding partner of the ECT2 oncoprotein. ECT2 is a guanine nucleotide exchange factor for the Rho family of small GTPases, and is also a critical regulator of cytokinesis. KLEIP is involved in actin assembly at sites of cell-cell adhesion in MDCK cells. KLEIP also controls vascular endothelial growth factor-induced endothelial migration and sprouting angiogenesis. Therefore, KLEIP seems to have diverse functions in various situations. Since some kelch-related proteins have relationships with cancer cells and KLEIP can interact with ECT2, KLEIP may be involved in carcinogenesis. In this study, we found that KLEIP was localized to the Golgi complex in cultured urothelial cells, indicating that KLEIP is a novel trans-Golgi network- associated protein. Next, we examined the KLEIP expression levels in 71 available specimens, comprising 8 normal epithelial cells and 63 transitional cell carcinomas (TCCs). KLEIP expression was observed in 5 of 8 normal epithelial cells and 49 of 63 TCCs, respectively. The intensity of KLEIP expression varied among the samples. Further analyses indicated that the intensity of KLEIP expression was correlated with the tumor grade, but not with the T stage. Therefore, KLEIP could represent a novel biomarker for urothelial cancer.