ART3 and cancer: One report found that overexpression of SIRT6 induces apoptosis in diverse cancer cell types, but not in normal cells, although this effect was dependent on the mono-ADP-ribosyltransferase activity of SIRT6, likely implying that SIRT6-induced apoptosis represents a function of SIRT6 distinct from its metabolic roles (Van Meter et al., 2011).