Induction of apoptosis in melanoma cell lines by p53 and its related proteins.
Melanoma cells rarely contain mutant p53 and hardly undergo apoptosis by wild-type p53. By using recombinant adenoviruses that express p53 or p53-related p51A or p73beta, we tested their apoptotic activities in melanoma cells. Yeast functional assay revealed a mutation of p53 at the 258th codon (AAA [K] instead of GAA [E]) in one cell line, 70W, out of six human melanoma cell lines analyzed (SK-mel-23, SK-mel-24, SK-mel-118, TXM18, 70W, and G361). Adenovirus-mediated transfer of p53, p51A, and/or p73beta suppressed growth and induced apoptotic DNA fragmentation of SK-mel-23, SK-mel-118, and 70W cells. Interestingly, p51A induced DNA fragmentation in them more significantly than p53 and p73beta. By Western blotting we analyzed levels of apoptosis-related proteins in cells expressing p53 family members. Apoptotic Bax and antiapoptotic Bcl-2 were not significantly upregulated or downregulated by expression of p53, p51A, or p73beta, except for p53-expressing 70W cells, which contained a larger amount of Bax protein than LacZ-expressing cells. Activation of caspase-3 was demonstrated only in p51A-expressing SK-mel-118 cells. We show here that p51A can mediate apoptosis in both wild-type and mutant p53-expressing melanoma cells more significantly than p53 and p73beta. It is also suggested that in melanoma cells (i) cellular target protein(s) other than Bcl-2 and Bax might be responsible for induction of p51A-mediated apoptosis and (ii) caspase-3 is not always involved in the apoptosis by p53 family members.
Yamashita
T
T
Department of Dermatology, Cancer Research Institute, Sapporo Medical University School of Medicine, Sapporo, Japan. yamasita@sapmed.ac.jp
Tokino
T
T
Tonoki
H
H
Moriuchi
T
T
Jin
H Y
HY
Omori
F
F
Jimbow
K
K
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000494:pharmacology; D004789:Enzyme Activation; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006706:Homeostasis; D006801:Humans; D008545:Melanoma / Q000473:pathology / Q000503:physiopathology*; D005810:Multigene Family; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases