Abundant expression of spliced HDM2 in Hodgkin lymphoma cells does not interfere with p14(ARF) and p53 binding.
Recently, comparative genomic hybridization (CGH)- and fluorescence in situ hybridization (FISH)-analyses of native Hodgkin and Reed-Sternberg (H&RS) cells extracted from Hodgkin lymphoma (HL) revealed a recurrent amplification of the HDM2 locus on chromosome 12. HDM2 is known to target, inactivate and to degrade p53. Wild type (wt) p53 protein is detected in high levels in HL. Simultaneously, stabilized wt p53 and spliced hdm2 transcripts have been observed in different tumors. Therefore, we examined the expression and structure of HDM2 in HL cell lines and possible effects on components of the p53 pathway. DNA integrity and induction potential of p53 was verified by DNA sequencing and detection of potential effector proteins (p21(WAF/CIP), HDM2) using immunofluorescence, respectively. All HL cell lines show an overexpression of HDM2 protein. Furthermore, several different spliced hdm2 transcripts (mdm-sv) including five new variants lacking a functional p53 binding site were characterized. If expressed, corresponding proteins were shown to be not restricted to the nucleus. Co-localization of the potential binding partners HDM2/p14(ARF) and HDM2/p53 was found in HL cell lines. We suggest that HDM2-sv have no significant disturbing influence on the interaction of these proteins.
Stürzenhofecker
Benjamin
B
Department of Haematologie and Oncology, Georg August University, Goettingen 37075, Germany. b.stuerzen@med.uni-goettingen.de
Schlott
Thilo
T
Quentin
Thomas
T
Kube
Dieter
D
Jung
Wolfram
W
Trümper
Lorenz
L
D017398:Alternative Splicing; D001665:Binding Sites; D045744:Cell Line, Tumor / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D006689:Hodgkin Disease / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D051736:Proto-Oncogene Proteins c-mdm2; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D016539:Reed-Sternberg Cells / Q000378:metabolism; D017384:Sequence Deletion; D025803:Tumor Suppressor Protein p14ARF / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D025803:Tumor Suppressor Protein p14ARF; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2