title: p33(ING1) enhances UVB-induced apoptosis in melanoma cells.
abstract: The biological functions of the tumor suppressor ING1 have been studied extensively in the past few years since it was cloned. It shares many biological functions with p53 and has been reported to mediate growth arrest, senescence, apoptosis, anchorage-dependent growth, chemosensitivity, and DNA repair. Some of these functions, such as cell cycle arrest and apoptosis, have been shown to be dependent on the activity of both ING1 and p53 proteins. Two recent reports by Scott and colleagues demonstrate that p33(ING1) (one of the ING1 isoforms) translocates to the nucleus and binds to PCNA upon UV irradiation. Here we report that p33(ING1) mediates UV-induced cell death in melanoma cells. We found that overexpression of p33(ING1) increased while the introduction of an antisense p33(ING1) plasmid reduced the apoptosis rate in melanoma cells after UVB irradiation. We also demonstrated that enhancement of UV-induced apoptosis by p33(ING1) required the presence of p53. Moreover, we found that p33(ING1) enhanced the expression of endogenous Bax and altered the mitochondrial membrane potential. Taken together, these observations strongly suggest that p33(ING1) cooperates with p53 in UVB-induced apoptosis via the mitochondrial cell death pathway in melanoma cells.
authors.affiliation: Division of Dermatology, Department of Medicine, University of British Columbia, Vancouver Hospital and Health Sciences Centre, Vancouver, British Columbia, V6H 3Z6, Canada.
authors.forename: K-John
authors.initials: KJ
authors.lastname: Cheung
authors.forename: Gang
authors.initials: G
authors.lastname: Li
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005260:Female; D016147:Genes, Tumor Suppressor; D006131:Growth Inhibitors / Q000378:metabolism; D006801:Humans; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D008545:Melanoma; D008564:Membrane Potentials / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D009687:Nuclear Proteins; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D014466:Ultraviolet Rays; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; C501503:ING1 protein, human; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein