title: Signal antonymy unique to myelodysplastic marrows correlates with altered expression of E2F1.
abstract: Myelodysplastic syndromes (MDS) have previously been reported to show competitively high rates of apoptosis and proliferation in the bone marrow (BM). Using a double-labelling technique in the present study, we demonstrated that a significantly high number of S-phase cells were simultaneously apoptotic (signal antonymy; SA) in MDS (mean +/- s.e.m. 53.5 +/- 6.7%, n = 24, P < 0.001). In contrast, SA was negligible in all other specimens studied, including normal control BM (n = 13) from non-Hodgkin's lymphoma (NHL) patients, BM from patients with de novo acute myelogenous leukaemia (1'AML; n = 5), or secondary AML that had transformed from MDS (2'AML; n = 10), or the solid tumours from patients with NHL (n = 9) or head and neck squamous cell carcinoma (HNSCC; n = 10). Subsequently, the expression of a transcription factor, E2F1, was studied in density-separated BM aspirate mononuclear cells from MDS patients (n = 9) and a normal control. Two separate sets of primers were used that recognized the regulatory retinoblastoma (Rb) protein-binding region and the functional DNA-binding region of E2F1. Interestingly, although the latter manifested the expected band (280 bp) in all samples, the Rb-specific primers showed the expected band (380 bp) in the normal and in 4/9 MDS specimens. Two other MDS specimens also showed a smaller band ( approximately 325 bp), whereas 3/9 MDS patients showed exclusively the smaller band. The levels of SA were significantly higher in those MDS cases that showed the smaller Rb-specific band either alone or in addition to the expected band (median 19.5%, n = 4, P = 0.037) than in those showing exclusively the expected band (median 0.4%, n = 3). Our present studies show SA as a characteristic feature of MDS and, importantly, demonstrate its link with an altered expression of E2F1 in some MDS patients.
authors.affiliation: Rush Cancer Institute, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA. smundle@rush.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Mundle
authors.forename: B Y
authors.initials: BY
authors.lastname: Mativi
authors.forename: J D
authors.initials: JD
authors.lastname: Cartlidge
authors.forename: B
authors.initials: B
authors.lastname: Dangerfield
authors.forename: L
authors.initials: L
authors.lastname: Broady-Robinson
authors.forename: B
authors.initials: B
authors.lastname: Li
authors.forename: V
authors.initials: V
authors.lastname: Shetty
authors.forename: P
authors.initials: P
authors.lastname: Venugopal
authors.forename: S A
authors.initials: SA
authors.lastname: Gregory
authors.forename: H D
authors.initials: HD
authors.lastname: Preisler
authors.forename: A
authors.initials: A
authors.lastname: Raza
mesh_terms: D017209:Apoptosis; D001854:Bone Marrow Cells / Q000473:pathology*; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002455:Cell Division; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D006801:Humans; D020287:In Situ Nick-End Labeling; D009190:Myelodysplastic Syndromes / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis; D056465:Retinoblastoma-Binding Protein 1; D016196:S Phase; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D012333:RNA, Messenger; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors