Misregulation of Rad50 expression in melanoma cells.
DNA double-strand breaks are increased in human melanoma tissue as detected by histone H2AX phosphorylation.(1-3) We investigated two of the downstream effectors of DNA double-strand breaks, Rad50 and 53BP1 (tumor suppressor p53 binding protein 1), to determine if they are altered in human primary melanoma cells. Melanoma cases showed high Rad50 staining (81.8%; 9/11) significantly more frequently than conventional or atypical melanocytic nevi (0%; 0/18). In contrast, the staining pattern for 53BP1 appears similar between melanoma and nevi. This is the first study that shows activation and misregulation of the DNA repair pathway in human melanoma cells. The staining features of Rad50, a component of an essential DNA double-strand break repair complex, are clearly increased in melanoma cells with regards to both staining intensity and the number of positive melanoma cells. Interestingly, among the melanoma cases with increased Rad50 staining, most demonstrated cytoplasmic rather than nuclear staining (88.9%, 8/9). Further studies are needed to determine the cause of this mislocalization and its affects, if any, on DNA double-strand break repair in melanoma.
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Nathan L
NL
Avaritt
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Richard
R
Owens
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.|Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Signe K
SK
Larson
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Matthew
M
Reynolds
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Stephanie
S
Byrum
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Kim M
KM
Hiatt
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Bruce R
BR
Smoller
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Alan J
AJ
Tackett
Department of Biochemistry, University of Arkansas for Medical Sciences, Little Rock, AR 72205.|Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
Wang L
WL
Cheung
D017766:Acid Anhydride Hydrolases; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000096:biosynthesis*; D004273:DNA, Neoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D008545:Melanoma / Q000201:enzymology / Q000473:pathology; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D009508:Nevus, Pigmented / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D014407:Tumor Cells, Cultured; D000071857:Tumor Suppressor p53-Binding Protein 1
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D045643:DNA Repair Enzymes