It has also been reported that

the overexpression of RhoC enhances metastasis, whereas dominant-negative expression of RhoC inhibits metastasis [27]. In addition, statins have been reported to inhibit tumor cell migration and invasion phosphatase inhibitor library through the suppressing geranylgeranylation of Rho in breast and colon cancer cell lines [28, 29]. These findings suggest that statins may bring about their anti-metastatic effects by inactivating the Rho/ROCK pathway. Cell migration is known to be required for tumor metastasis. In this study, we showed that statins inhibited the migration of B16BL6 cells. It has been reported that YM529/ONO-5920 and zoledronate, nitrogen-containing bisphosphonates, inhibited hepatocellular carcinoma and osteosarcoma cell migration by suppressing

GGPP biosynthesis [30, 31]. Collectively, the findings suggest that the inhibition of GGPP biosynthesis plays an important role in the suppression of B16BL6 cell migration by statins. Matrix metalloproteinases (MMPs) and zinc-dependent endopeptidases are a family of structurally related zymogens that are capable of degrading the ECM, including the basement membrane. They are presumed to be critically involved in tumor invasion and metastasis [32]. In melanomas, higher levels of MMP-1, MMP-2, MMP-9, and MMP-14 have been observed in the more invasive and metastatic tumors [33]. Moreover, overexpression of RhoA-GTP induces MMP LY294002 mw expression and activity [34]. We observed that statins significantly inhibit the mRNA expression and enzymatic activities of MMP-1, MMP-2, MMP-9, and MMP-14 in B16BL6 cells. These results suggest that HSP90 the decrease in the activation of Rho is vital for the suppression of MMP expressions by statins in B16BL6 cells. Cell adhesion is a fundamental cellular response that is intricately involved in the physiological processes of proliferation, motility,

as well as the pathology of neoplastic transformation and metastasis. Integrins are the most important family of cell surface adhesion molecules that mediate interactions between cells and the ECM. Members of the β1 integrin subfamily are known to primarily bind to collagens, fibronectins, and laminins. We found that statins suppress cell adhesion to type I collagen, type IV collagen, fibronectin, and laminin. Furthermore, statins significantly inhibited the mRNA and protein expressions of integrin α2, integrin α4, and integrin α5. A recent study has reported that the activation of small GTPases increased cell adhesion to collagens, fibronectins, and laminins [35]. These findings indicate that the Rho/ROCK pathway may be essential for the expressions of integrin α2, integrin α4, and integrin α5. Activation of Rho could lead to the activation of LIMK and MLC [36]. These signal transduction factors are essential for cell migration, invasion, adhesion, and metastasis [37–39].