• Open Access

von Willebrand factor type D domain mutant of SVS-1/SUSD2, vWDm, induces apoptosis in HeLa cells


To whom correspondence should be addressed. E-mail: andoh@t.soka.ac.jp


SVS-1/SUSD2 is a novel gene, which inhibits growth and reverses tumorigenic phenotypes of cancer cells in vitro. Here we report identification of a mutant of SVS-1, designated SVS-1-vWDm, in which conserved amino acids GLLG at positions 591–594 in von Willebrand factor type D (vWD) domain are replaced by AAAA. As observed by laser confocal microscope, intracellular localization of the mutant protein has changed such that both the N-terminus and the C-terminus of SVS-1-vWDm were localized in the inner surface of the plasma membrane, whereas the N-terminus of SVS-1 was localized in the outer surface of the plasma membrane. Additionally, SVS-1-vWDm was processed much less efficiently and in a slightly different manner. In in vitro studies, adenovirus-mediated transduction of the SVS-1-vWDmgene induced growth suppression of HeLa cells in a dose-dependent manner, as the wild-type gene and inhibition of anchorage-independent growth. Of great interest is the finding that the mutant protein, vWDm, but not the wild-type one induced apoptosis, as observed by nuclear as well as DNA fragmentation. Activation of caspase-3 and -9, but not caspase-8 or -12, was also demonstrated in vWDm-expressing cells. An inhibition of Akt phosphorylation, a major survival signaling component, also occurred in vWDm-expressing HeLa cells. Together these data suggest that vWDm induces apoptosis by inactivation of survival signaling component Akt and activation of caspase cascade (mitochondrial pathway) in HeLa cells. We propose SVS-1-vWDmas an alternative gene for use in developing new therapeutic strategies for the treatment of cancer. (Cancer Sci 2007; 98: 909–915)