Rhogdi2 And Evl Expression And Function Of Research In The Development And Progression Of Human Breast Cancer

Breast cancer remains the most commonly diagnosed cancer for women in the world, and the second largest cause of their cancer deaths. Metastasis is the most lethal attribute of breast cancer. There is a critical need to identify and investigate tumorigenesis and metastasis related genes for cancer diagnosis and therapy. Rho GDP dissociation inhibitors (RhoGDIs) constitute a family with three members in mammalian: RhoGDI1, RhoGDI2 and RhoGDI3. RhoGDIs are thought to regulate RhoGTPases by inhibiting the dissociation of the bound GDP and the hydrolyzation of the bound GTP, and act as shuttle proteins to recruit RhoGTPases to their effector site and to recycle them back to cytosol. RhoGDI2 has been shown to be a metastasis related gene in several cancers. In human breast cancer, little clinical study of RhoGDI2 has been reported. In this study, we investigated the expression level of RhoGDI2 by immunohistochemistry, as well as the correlation of RhoGDI2 with clinicopathological parameters in 71 breast cancer specimens. We also examined RhoGDI2 expression at mRNA and protein levels of four human breast cancer cell lines differing in in vivo metastasis. Along with the extent of mammary epithelia proliferation and carcinogenesis, a biphasic pattern of RhoGDI2 expression (increase and then decrease) was observed, which was also found in those examined cell lines. Furthermore, univariate and multivariate analysis revealed that reduced expression of RhoGDI2 in the most malignant epithelia was significantly associated with lymph node metastasis (P<0.01). In order to understand whether RhoGDI2 acts as a metastasis suppressor in human breast cancer, we investigated the effect of RhoGDI2 overexpression on the tumorigenic and metastatic ability of human breast cancer cell line MDA-MB-231 by in vitro growth curve assay, cell cycle assay, colony formation in soft agar assay, scratch wound assay, Boyden chamber invasive assay and in vivo metastasis assay. RhoGDI2 appeared to inhibit the metastasis of MDA-MB-231 and may be involved in tumorigenesis in vitro, whereas its role in vivo remained to be elucidated. Our results suggest that RhoGDI2 may be implicated in the progress of malignancy and act as a metastasis-related marker in breast cancer.The cancer genome anatomy project (CGAP) provides a powerful research platform for cancer researchers to screen the tumorigenesis and metastasis related genes by bioinformatics methods. We utilized the serial analysis of gene expression (SAGE) databases of the CGAP to mine genes expressed differentially in normal and cancerous breast tissues and cell lines by gene expression display (DGED). The database screened genes were further identified by using RT-PCR in breast cancer cell lines and tissues. EVL was upregulated in tumor specimens according to both the bioinformatical results and mRNA expression analysis. EVL belongs to the Ena/VASP (Enabled/vasodilator-stimulated phosphoprotein) family that including Mena, VASP and EVL, which have a wide range of roles in regulating the actin cytoskeleton. Growing evidence suggests that Mena and VASP are involved in carcinogenesis, but little is known about the significance of EVL's function in cancer. This study examined the expression levels of EVL mRNA in paired breast cancer specimens using semi-quantitative and real-time RT-PCR. In a comparison between matched breast tumor and normal tissues, a significant increase in the level of EVL mRNA was found in 23 of the 35 (65.7%) tumors (P=0.032). And the EVL mRNA relative expression level significantly corrected with clinical stages (P=0.021). To begin elucidating the mechanism, we measured the ability of EVL to transform NIH3T3 cells and regulate the motility of MCF-7 cells in vitro by focus formation, cell proliferation and cell migration assays. The results indicated that over-expression of EVL was insufficient to transform NIH3T3 cells, but the motility of EVL transfected MCF-7 cells was markedly promoted. Collectively, EVL expression level was higher in breast tumors compared to normal tissues; its up-regulation was positively associated with the clinical stages of breast cancer. Additionally, EVL may be implicated in invasion and/or metastasis of human breast cancer.