Inhibition of migration and invasion of LNCaP human prostate carcinoma cells by cordycepin through inactivation of Akt

Cordycepin (3'-deoxyadenosine), a major bioactive compound of Cordyceps militaris, has many pharmacological actions, such as anti-inflammatory and anticancer activities. In this study, the relationship between inhibition of cell motility and anti-invasive activity by cordycepin in LNCaP human prostate carcinoma cells was investigated. Within the concentration range that was not cytotoxic, cordycepin time-dependently inhibited cell motility and invasiveness of LNCaP cells. The inhibitory effects of cordycepin on cell invasiveness were associated with tightening of tight junctions (TJs), which was demonstrated by an increase in transepithelial electrical resistance (TER). Immunoblotting indicated that cordycepin decreases levels of claudin proteins, which are major components of TJs that play a key role in control and selectivity of paracellular transport. Furthermore, cordycepin inhibited the expression and activity of matrix metalloproteinase (MMP)-2 and MMP-9, and simultaneously increased levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. These effects were related to inactivation of the phosphoinositide 3-kinase (PI3K)/Akt pathway in LNCaP cells. These findings suggest that cordycepin inhibits the migration and invasion of LNCaP cells by downregulating the activity of TJs and MMPs, possibly in association with suppression of Akt activation.