The immune system is important for elimination of residual leukemic cells during acute myeloid leukemia (AML) therapy. Anti-leukemia immune response can be inhibited by various mechanisms leading to immune evasion and disease relapse. Selected markers of immune escape were analyzed on AML cells from leukapheresis at diagnosis (N = 53). Hierarchical clustering of AML immunophenotypes yielded distinct genetic clusters. In the absence of DNMT3A mutation, NPM1 mutation was associated with decreased HLA expression and low levels of other markers (CLIP, PD-L1, TIM-3). Analysis of an independent cohort confirmed decreased levels of HLA transcripts in patients with NPM1 mutation. Samples with combined NPM1 and DNMT3A mutations had high CLIP surface amount suggesting reduced antigen presentation. TIM-3 transcript correlated not only with TIM-3 surface protein but also with CLIP and PD-L1. In our cohort, high levels of TIM-3/PD-L1/CLIP were associated with lower survival. Our results suggest that AML genotype is related to blast immunophenotype, and that high TIM-3 transcript levels in AML blasts could be a marker of immune escape. Cellular pathways regulating resistance to the immune system might contribute to the predicted response to standard therapy of patients in specific AML subgroups and should be targeted to improve AML treatment.

• Klíčová slova
• AML, DNMT3A, NPM1, TIM-3, immunophenotype,
• MeSH
• akutní myeloidní leukemie * diagnóza   genetika   MeSH
• antigeny CD274 genetika   MeSH
• biologické markery MeSH
• buněčný receptor 2 viru hepatitidy A genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• lidé MeSH
• mutace MeSH
• nukleofosmin * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD274 MeSH
• biologické markery MeSH
• buněčný receptor 2 viru hepatitidy A MeSH
• DNA methyltransferasa 3A * MeSH
• DNMT3A protein, human MeSH Prohlížeč
• NPM1 protein, human MeSH Prohlížeč
• nukleofosmin * MeSH

Nucleophosmin (NPM1, B23) is a multifunctional phosphoprotein expressed in all tissues. The protein is mainly localized in nucleoli. In hematological malignancies, NPM1 belongs to commonly altered genes. Its mutation, always heterozygous, leads to the re-localization of the NPM1 protein from the nucleolus to the cytoplasm (NPM1c+). NPM1c+ is found in 30% of acute myeloid leukemia (AML). Our study showed that an AML patient, whose leukemia cells carried the NPM1c+ mutation and who was the recipient of allogeneic HSCT from a haploidentical donor, raised a robust allorestricted CD8+ T cell response directed against the NPM1wt protein. Favourably, the response against NPM1wt was not accompanied by side effects such as GvHD. Moreover, the induction of a high NPM1wt-specific response coincided with the decrease in NPM1c+ transcripts detected, implying a beneficial graft versus leukemia effect. On the basis of these results, we suppose that TCRs from allorestricted NPM1wt-specific T cells are worth studying in other recipients of grafts from haploidentical donors as a possible tool for TCR gene therapy.

• Klíčová slova
• T cell response, acute myeloid leukemia, hematopoietic stem cell transplantation, mutation, nucleophosmin 1,
• MeSH
• akutní myeloidní leukemie * genetika   metabolismus   terapie   MeSH
• CD8-pozitivní T-lymfocyty metabolismus   patologie   MeSH
• hematopoetické kmenové buňky metabolismus   patologie   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• nukleofosmin * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• jaderné proteiny MeSH
• nukleofosmin * MeSH

Nucleophosmin (NPM) mutations causing its export from the nucleoli to the cytoplasm are frequent in acute myeloid leukemia (AML). Due to heterooligomerization of wild type NPM with the AML-related mutant, the wild-type becomes misplaced from the nucleoli and its functions are significantly altered. Dissociation of NPM heterooligomers may thus restore the proper localization and function of wild-type NPM. NSC348884 is supposed to act as a potent inhibitor of NPM oligomerization. The effect of NSC348884 on the NPM oligomerization was thoroughly examined by fluorescence lifetime imaging with utilization of FRET and by a set of immunoprecipitation and electrophoretic methods. Leukemia-derived cell lines and primary AML cells as well as cells transfected with fluorescently labeled NPM forms were investigated. Our results clearly demonstrate that NSC348884 does not inhibit formation of NPM oligomers neither in vivo nor in vitro. Instead, we document that NSC348884 cytotoxicity is rather associated with modified cell adhesion signaling. The cytotoxic mechanism of NSC348884 has therefore to be reconsidered.

• MeSH
• apoptóza účinky léků   MeSH
• HEK293 buňky MeSH
• indoly farmakologie   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• leukemie farmakoterapie   genetika   metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nukleofosmin MeSH
• protinádorové látky farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• indoly MeSH
• jaderné proteiny MeSH
• NPM1 protein, human MeSH Prohlížeč
• NSC 348884 MeSH Prohlížeč
• nukleofosmin MeSH
• protinádorové látky MeSH

Compared to solid tumors, the role of PD-L1 in hematological malignancies is less explored, and the knowledge in this area is mostly limited to lymphomas. However, several studies indicated that PD-L1 is also overexpressed in myeloid malignancies. Successful treatment of the acute myeloid leukemia (AML) is likely associated with elimination of the residual disease by the immune system, and possible involvement of PD-L1 in this process remains to be elucidated. We analyzed PD-L1 expression on AML primary cells by flow cytometry and, in parallel, transcript levels were determined for the transcription variants v1 and v2. The ratio of v1/v2 cDNA correlated with the surface protein amount, and high v1/v2 levels were associated with worse overall survival (p = 0.0045). The prognostic impact of PD-L1 was limited to AML with mutated nucleophosmin and concomitant internal tandem duplications in the FLT3 gene (p less than 0.0001 for this particular AML subgroup).

• Klíčová slova
• AML, CD34, FLT3-ITD, NPM1, PD-1, PD-L1 transcript, leukemia,
• MeSH
• akutní myeloidní leukemie krev   genetika   MeSH
• antigeny CD274 krev   genetika   metabolismus   MeSH
• jaderné proteiny genetika   MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• mutace MeSH
• nádorové biomarkery krev   genetika   metabolismus   MeSH
• nukleofosmin MeSH
• tyrosinkinasa 3 podobná fms genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD274 MeSH
• CD274 protein, human MeSH Prohlížeč
• FLT3 protein, human MeSH Prohlížeč
• jaderné proteiny MeSH
• messenger RNA MeSH
• nádorové biomarkery MeSH
• NPM1 protein, human MeSH Prohlížeč
• nukleofosmin MeSH
• tyrosinkinasa 3 podobná fms MeSH

Acute myeloid leukemia with mutated nucleophosmin (NPMc+ AML) forms a distinct AML subgroup with better prognosis which can potentially be associated with immune response against the mutated nucleophosmin (NPM). As the T-cell-mediated immunity involves antigen presentation on HLA class I molecules, we hypothesized that individuals with suitable HLA type could be less prone to develop NPMc+ AML. We compared HLA class I distribution in NPMc+ AML patient cohort (398 patients from 5 centers) with the HLA allele frequencies of the healthy population and found HLA-A*02, B*07, B*40 and C*07 underrepresented in the NPMc+ AML group. Presence of B*07 or C*07:01 antigen was associated with better survival in patients without concomitant FLT3 internal tandem duplication. Candidate NPM-derived immunopeptides were found for B*40 and B*07 using prediction software tools. Our findings suggest that a T-cell-mediated immune response could actually explain better prognosis of NPMc+ patients and provide a rationale for attempts to explore the importance of immunosuppressive mechanisms in this AML subgroup.

• MeSH
• akutní myeloidní leukemie * genetika   imunologie   mortalita   MeSH
• buněčná imunita * MeSH
• dospělí MeSH
• jaderné proteiny * genetika   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• MHC antigeny I. třídy * genetika   imunologie   MeSH
• míra přežití MeSH
• nádorové proteiny * genetika   imunologie   MeSH
• nukleofosmin MeSH
• prevalence MeSH
• přežití bez známek nemoci MeSH
• senioři MeSH
• T-lymfocyty imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• jaderné proteiny * MeSH
• MHC antigeny I. třídy * MeSH
• nádorové proteiny * MeSH
• NPM1 protein, human MeSH Prohlížeč
• nukleofosmin MeSH

Mutations of the gene for nucleophosmin (NPM1) are the most frequent genetic aberration in patients with acute myeloid leukemia (AML). The mechanism of leukemic transformation in this leukemia subtype is not fully understood, but aberrant cytoplasmic localization of mutated NPM (NPMmut) is widely considered as an important factor for leukemia manifestation. We analyzed the subcellular localization of three types of NPM with a C-terminal mutation (A, B and E). Genes for the individual NPM forms were fused with a gene for one of fluorescent protein variants in plasmids, which were transfected into three cell lines with different endogenous NPM expression. Subcellular localization of the fluorescent protein-labeled NPM was further correlated with the relative expression of all NPM forms. We confirmed a high cytoplasmic expression of NPMmutA and NPMmutB whereas a substantial fraction of NPMmutE was found to be localized in nucleoli. Moreover, we revealed that the localization of fluorescently labeled NPM is affected by the interaction between various forms of the protein.

• MeSH
• akutní myeloidní leukemie metabolismus   MeSH
• buňky NIH 3T3 MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• mutace * MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nukleofosmin MeSH
• subcelulární frakce metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• jaderné proteiny MeSH
• NPM1 protein, human MeSH Prohlížeč
• Npm1 protein, mouse MeSH Prohlížeč
• nukleofosmin MeSH