Foot-and-mouth disease virus induces lysosomal degradation of NME1 to impair p53-regulated interferon-inducible antiviral genes expression.

Nucleoside diphosphate kinase 1 (NME1) is well-known as a tumor suppressor that regulates p53 function to prevent cancer metastasis and progression. However, the role of NME1 in virus-infected cells remains unknown. Here, we showed that NME1 suppresses viral replication in foot-and-mouth disease virus (FMDV)-infected cells. NME1-enhanced p53-mediated transcriptional activity and induction of interferon-inducible antiviral genes expression. FMDV infection decreased NME1 protein expression. The 2B and VP4 proteins were identified as the viral factors that induced reduction of NME1. FMDV 2B protein has a suppressive effect on host protein expression. We measured, for the first time, VP4-induced lysosomal degradation of host protein; VP4-induced degradation of NME1 through the macroautophagy pathway, and impaired p53-mediated signaling. p53 plays significant roles in antiviral innate immunity by inducing several interferon-inducible antiviral genes expression, such as, ISG20, IRF9, RIG-I, and ISG15. VP4 promoted interaction of p53 with murine double minute 2 (MDM2) through downregulation of NME1 resulting in destabilization of p53. Therefore, 5-flurouracil-induced upregulation of ISG20, IRF9, RIG-I, and ISG15 were suppressed by VP4. VP4-induced reduction of NME1 was not related to the well-characterized blocking effect of FMDV on cellular translation, and no direct interaction was detected between NME1 and VP4. The 15-30 and 75-85 regions of VP4 were determined to be crucial for VP4-induced reduction of NME1. Deletion of these VP4 regions also inhibited the suppressive effect of VP4 on NME1-enhanced p53 signaling. In conclusion, these data suggest an antiviral role of NME1 by regulation of p53-mediated antiviral innate immunity in virus-infected cells, and reveal an antagonistic mechanism of FMDV that is mediated by VP4 to block host innate immune antiviral response.

Identification of NM23-H2 as a tumour-associated antigen in chronic myeloid leukaemia.

Therapeutic effects of haematopoietic stem cell transplantation are not limited to maximal chemoradiotherapy and subsequent bone marrow regeneration, but include specific as well as unspecific immune reactions known as graft-versus-leukaemia (GvL) effects. Specific immune reactions are likely to be particularly relevant to the long-term treatment of diseases, such as chronic myeloid leukaemia (CML), in which residual cells may remain quiescent and unresponsive to cytotoxic and molecular therapies for long periods of time. Specific GvL effects result from the expression on leukaemic cells of specific tumour-associated antigens (TAAs) in the context of HLA proteins. As human leukocyte antigen (HLA) types vary widely, the development of broadly applicable tumour vaccines will require the identification of multiple TAAs active in different HLA backgrounds. Here, we describe the identification of NM23-H2 as a novel HLA-A32-restricted TAA of CML cells and demonstrate the presence of specifically reactive T cells in a patient 5 years after transplantation. As the NM23 proteins are aberrantly expressed in a range of different tumours, our findings suggest potential applications beyond CML and provide a new avenue of investigation into the molecular mechanisms underlying CML.