RHOA and neoplasm: To explore whether SF is also regulated by RhoA in tumor cells, we transfected MTF7 and LLC cells with vector alone, dominant-negative Thr19Asn RhoA mutant (RhoA-DN), which loses binding ability to guanidine nucleotides but is able to compete with endogenous GDP-bound RhoA for guanidine nucleotide exchanging factor (GEF)-binding and prevents GDP bound on endogenous RhoA from being exchanged into GTP, and constitutively active Gln63Leu RhoA mutant (RhoA-CA), in which the bound GTP can no longer be hydrolyzed into GDP [43,44].