title: Differential expression and function of A20 and TRAF1 in Hodgkin lymphoma and anaplastic large cell lymphoma and their induction by CD30 stimulation.
abstract: A20 and TRAF1 are two anti-apoptotic components of the intracellular signalling pathway of the tumour necrosis factor receptor (TNFR) family. Induction of apoptosis seems to be a main function of these receptors. It is astonishing that a member of this family, CD30, is overexpressed by highly proliferating tumours such as Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL). It is known that CD30 stimulation leads to the apoptosis of ALCL tumour cells but not of Hodgkin-Reed-Sternberg (HRS) cells. We have already established the overexpression of TRAF1 in HRS cells. In this study we demonstrate that A20 is highly expressed in the HRS cells in 20/22 of cases of classical HL, in 4/4 cases of nodular lymphocyte-predominant HL (NLPHL), and in 2/2 cases of the anaplastic variant of diffuse large B cell lymphoma. In contrast, all other non-Hodgkin lymphomas, including ALCL, revealed either no A20 reactivity, or reactivity in less than 1% of all tumour cells. CD30 stimulation induced A20 and TRAF1 expression. This effect was most prominent in HL and ALCL cell lines with low basal expression levels of these molecules. Immunohistological studies of reactive lymphoid blasts in tonsillar tissue demonstrated that co-expression of CD30, A20, and TRAF1 also occurs in vivo. Cell lines with high basal A20 and TRAF1 expression were resistant to CD30-mediated apoptosis. The sensitivity to CD30-induced apoptosis was increased by inhibition of protein synthesis. TRAF1 transfection decreased CD30-induced apoptosis. Our data suggest that A20 and TRAF1 contribute to apoptosis resistance and, therefore, play an important role in the pathogenesis of classical HL.
authors.affiliation: Institut für Pathologie, UK Benjamin Franklin, Freie Universität Berlin, Germany. duerkop@medizin.fu-berlin.de
authors.forename: Horst
authors.initials: H
authors.lastname: Dürkop
authors.forename: Burkhard
authors.initials: B
authors.lastname: Hirsch
authors.forename: Corinna
authors.initials: C
authors.lastname: Hahn
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Foss
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
mesh_terms: D017209:Apoptosis; D002455:Cell Division; D004268:DNA-Binding Proteins; D006689:Hodgkin Disease / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D006965:Hyperplasia / Q000378:metabolism; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D017730:Ki-1 Antigen / Q000502:physiology; D017728:Lymphoma, Large-Cell, Anaplastic / Q000378:metabolism* / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins; D014066:Palatine Tonsil / Q000473:pathology; D011506:Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D047990:TNF Receptor-Associated Factor 1; D014407:Tumor Cells, Cultured; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D017730:Ki-1 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011506:Proteins; D047990:TNF Receptor-Associated Factor 1; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3