Cudratricusxanthone G (CTXG), a natural bioactive cudratricusxanthone extracted 
from C. tricuspidata, has shown anti-cancer properties. However, the function 
and mechanism of CTXG in tumor invasion have not been elucidated to date. In 
this study, we investigated the inhibitory effect of CTXG on the proliferation, 
migration and invasion of SW620 cells. We found that MMP-2, a pivotal factor in 
tumor invasion, was suppressed in both expression and activation by CTXG in a 
dose-dependent manner. The suppression of MMP-2 expression by CTXG led to an 
inhibition of SW620 cells invasion and migration by inactivating Rac1 and Cdc42 
but not RhoA GTPase. Furthermore, CTXG also inhibited the transcriptional 
activity of AP-1 (activator protein-1). In conclusion, our data demonstrate that 
CTXG exerted anti-invasion action in SW620 cells by targeting MMP-2 though 
regulating the activities of Rac1, Cdc42 and their downstream transcriptional 
factor AP-1. These results are the first to reveal the novel functions of CTXG 
in cancer cell invasion and its molecular basis for the anti-cancer action.