Resistance to glucocorticoids (GC), the common agents for remission induction in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL), poses a significant therapeutic hurdle. Therefore, dissecting the mechanisms shaping GC resistance could lead to new treatment modalities. Here, we showed that CD9- BCP-ALL cells were preferentially resistant to prednisone and dexamethasone over other standard cytotoxic agents. Concordantly, we identified significantly more poor responders to the prednisone prephase among BCP-ALL patients with a CD9- phenotype, especially for those with adverse presenting features including older age, higher white cell count and BCR-ABL1. Furthermore, gain- and loss-offunction experiments dictated a definitive functional linkage between CD9 expression and GC susceptibility, as demonstrated by the reversal and acquisition of relative GC resistance in CD9low and CD9high BCP-ALL cells, respectively. Despite physical binding to the GC receptor NR3C1, CD9 did not alter its expression, phosphorylation or nuclear translocation but potentiated the induction of GC-responsive genes in GC-resistant cells. Importantly, the MEK inhibitor trametinib exhibited higher synergy with GC against CD9- than CD9+ lymphoblasts to reverse drug resistance in vitro and in vivo. Collectively, our results elucidate a previously unrecognized regulatory function of CD9 in GC sensitivity, and inform new strategies for management of children with resistant BCP-ALL.

• MeSH
• antigeny CD9 * metabolismus   genetika   MeSH
• chemorezistence * genetika   MeSH
• dexamethason farmakologie   MeSH
• dítě MeSH
• glukokortikoidy * farmakologie   terapeutické užití   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• pre-B-buněčná leukemie * farmakoterapie   metabolismus   genetika   patologie   MeSH
• předškolní dítě MeSH
• receptory glukokortikoidů metabolismus   genetika   MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In the effort to improve immunophenotyping and minimal residual disease (MRD) assessment in acute lymphoblastic leukemia (ALL), the international Berlin-Frankfurt-Münster (iBFM) Flow Network introduced the myelomonocytic marker CD371 for a large prospective characterization with a long follow-up. In the present study, we aimed to investigate the clinical and biological features of CD371-positive (CD371pos) pediatric B-cell precursor ALL (BCP-ALL). From June 2014 to February 2017, 1812 pediatric patients with newly diagnosed BCP-ALLs enrolled in trial AIEOP-BFM ALL 2009 were evaluated as part of either a screening (n = 843, Italian centers) or validation cohort (n = 969, other iBFM centers). Laboratory assessment at diagnosis consisted of morphological, immunophenotypic, and genetic analysis. Response assessment relied on morphology, multiparametric flow cytometry (MFC), and polymerase chain reaction (PCR)-MRD. At diagnosis, 160 of 1812 (8.8%) BCP-ALLs were CD371pos. This correlated with older age, lower ETV6::RUNX1 frequency, immunophenotypic immaturity (all P < .001), and strong expression of CD34 and of CD45 (P < .05). During induction therapy, CD371pos BCP-ALLs showed a transient myelomonocytic switch (mm-SW: up to 65.4% of samples at day 15) and an inferior response to chemotherapy (slow early response, P < .001). However, the 5-year event-free survival was 88.3%. Among 420 patients from the validation cohort, 27 of 28 (96.4%) cases positive for DUX4-fusions were CD371pos. In conclusion, in the largest pediatric cohort, CD371 is the most sensitive marker of transient mm-SW, whose recognition is essential for proper MFC MRD assessment. CD371pos is associated to poor early treatment response, although a good outcome can be reached after MRD-based ALL-related therapies.

• MeSH
• buněčný rodokmen MeSH
• dítě MeSH
• imunofenotypizace MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• pre-B-buněčná leukemie * genetika   mortalita   farmakoterapie   patologie   diagnóza   terapie   metabolismus   MeSH
• předškolní dítě MeSH
• protokoly antitumorózní kombinované chemoterapie terapeutické užití   MeSH
• reziduální nádor * diagnóza   MeSH
• tetraspaniny genetika   metabolismus   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

BACKGROUND: Bone marrow (BM) samples obtained from minimal residual disease (MRD)-negative children with B-cell acute lymphoblastic leukemia (B-ALL) were used in our laboratory as negative biological controls for the development of a neuroblastoma (NBL) flow-cytometric (FC) protocol. The accidental, but systematic, identification of rare cell populations (RCP) mimicking NBL cells (CD45- /CD56+ ) in these samples indicated the need for their thorough immunophenotypic identification, in order to elucidate their possible interference in NBL-MRD assessment. PROCEDURE: RCP observed in BM samples from 14 children recovering from BM aplasia due to intensive chemotherapy for B-ALL were investigated with the following markers: CD81, CD200, CD24, GD2, CD73, CD13, CD90, CD146, CD9, CD117, CD10, CD99, and NG2. BM samples from six newly diagnosed patients with NBL and an NBL cell line were simultaneously investigated as positive controls. RESULTS: The frequency of RCP in B-ALL BM samples was < 1/1 × 104 cells (bulky lysis), and their immunophenotypic profile was indicative of CD56+ mesenchymal stromal cells (MSCs) (CD45- , CD90+ , CD146+ , CD73+ ). Also, RCP expressed CD81 and CD200, simulating NBL cells. The most useful discriminative markers for CD56+ MSCs were CD13 and CD73. An appropriate protocol consisting of two tubes with seven color combinations was further proposed: SYTO-16, GD2 (first tube) or CD73 (second tube)-PE, CD24-ECD, CD13-PC5.5, CD45-PC7, CD81-APC, and CD56-APC700. CONCLUSIONS: RCP that were immunophenotypically similar to NBL were identified as CD56+ MSCs. As these cells might pose an obstacle to accurate NBL disease assessment by FC, especially MRD, an enhanced NBL-FC protocol is proposed for prospective evaluation.

• MeSH
• antigeny CD45 metabolismus   MeSH
• antigeny CD56 metabolismus   MeSH
• imunofenotypizace MeSH
• kostní dřeň metabolismus   patologie   MeSH
• lidé MeSH
• mezenchymální kmenové buňky metabolismus   patologie   MeSH
• následné studie MeSH
• neuroblastom diagnóza   etiologie   metabolismus   MeSH
• pre-B-buněčná leukemie komplikace   metabolismus   MeSH
• předškolní dítě MeSH
• prognóza MeSH
• prospektivní studie MeSH
• průtoková cytometrie MeSH
• reziduální nádor etiologie   metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• B-lymfocyty metabolismus   MeSH
• filadelfský chromozom * MeSH
• lidé MeSH
• makrofágy cytologie   MeSH
• pre-B-buněčná leukemie genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• dopisy MeSH
• komentáře MeSH

• MeSH
• dítě MeSH
• lidé MeSH
• nádorové biomarkery biosyntéza   genetika   MeSH
• pre-B-buněčná leukemie diagnóza   genetika   metabolismus   MeSH
• předškolní dítě MeSH
• receptory cytokinové biosyntéza   genetika   MeSH
• regulace genové exprese u leukemie * MeSH
• signální transdukce fyziologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• dopisy MeSH
• klinické zkoušky MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

The expression of drebrin, a cytoskeletal protein newly estimated by expression profiling to correlate with the genotype and prognosis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), was examined by independent methods. After demonstrating its higher expression in TEL/AML1(pos) BCP-ALL by quantitative reverse transcriptase polymerase chain reaction, we developed an anti-drebrin monoclonal antibody (mAb). In a cohort of 86 children with BCP-ALL, we found increased expression of drebrin in TEL/AML1(pos) ALL. In conclusion, relationship of drebrin expression and prognosis or genotype can now be assessed using flow cytometry.

• MeSH
• akutní nemoc MeSH
• fúzní onkogenní proteiny MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• monoklonální protilátky imunologie   MeSH
• myši MeSH
• neuropeptidy imunologie   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• pre-B-buněčná leukemie genetika   imunologie   metabolismus   MeSH
• prognóza MeSH
• protein PEBP2A2 MeSH
• průtoková cytometrie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVE: The aberrant expression of myeloid antigens on acute lymphoblastic leukemia (ALL) cells is a well-documented phenomenon. So far, there have been no reports of a functional consequence of this aberrant expression. The granulocytic marker carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6, CD66c) is a GPI-anchored molecule that is reported to be the most frequently aberrantly expressed myeloid marker in ALL with a strong correlation with genotype. MATERIALS AND METHODS: We mimicked CEACAM6 signaling in ALL cells by cross-linking with anti-CEACAM6 antibody. Next, we measured a response to CEACAM6 signaling by integrin subunits expression, integrin ligand binding, phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2), Akt, and p38 mitogen-activated protein kinase (MAPK) and apoptosis by flow cytometry. RESULTS: Following CEACAM6 cross-linking in ALL cells, we detected Erk1/2, Akt, and p38 MAPK phosphorylation and integrin upregulation, as well as enhanced binding of integrin ligands (vascular cell adhesion molecule-1 [VCAM-1] and intercellular cell adhesion molecule-1 [ICAM-1]). However, CEACAM6 signaling resulted in an increase in apoptosis, unlike other GPI-anchored molecules, such as CD24. CONCLUSION: The present study is the first to demonstrate the functional consequences of CEACAM6 cross-linking in B-cell precursor ALL cells.

• MeSH
• antigeny nádorové imunologie   metabolismus   MeSH
• apoptóza MeSH
• CD antigeny imunologie   metabolismus   MeSH
• fosforylace účinky léků   imunologie   MeSH
• GPI-vázané proteiny MeSH
• imunologický capping MeSH
• integriny imunologie   metabolismus   MeSH
• lidé MeSH
• MAP kinasový signální systém MeSH
• mezibuněčná adhezivní molekula-1 imunologie   metabolismus   MeSH
• mitogenem aktivovaná proteinkinasa 3 imunologie   metabolismus   MeSH
• mitogenem aktivované proteinkinasy p38 imunologie   metabolismus   MeSH
• molekuly buněčné adheze antagonisté a inhibitory   imunologie   metabolismus   MeSH
• nádorové buněčné linie MeSH
• onkogenní protein v-akt imunologie   metabolismus   MeSH
• pre-B-buněčná leukemie imunologie   metabolismus   MeSH
• protilátky nádorové imunologie   farmakologie   MeSH
• regulace genové exprese u leukemie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Acute leukemia is considered to be a two- or multiple-step process. Although there is a considerable knowledge regarding the character of the "first hit," the nature of the "second hit" remains unanswered in most of the cases including leukemias with MLL gene rearrangement. We demonstrate here a striking sequence of events, which include a covert, protracted preleukemic phase characterized by a dominant MLL/FOXO3A clone with intact myeloid differentiation and the subsequent acquisition of a secondary genetic abnormality, leading to overt lymphoblastic leukemia. Backtracking of the secondary acute lymphoblastic leukemia (sALL) with the MLL rearrangement showed no blasts in the bone marrow (BM) during the protracted preleukemic phase. However, at the same time (more than 1 year before the sALL diagnosis) the MLL/FOXO3A was present in up to 90% of BM cells including myeloid lineage, suggesting that the fusion arose in a multipotent progenitor. To identify potential "second hit" precipitating sALL we compared DNA in preleukemic versus fully leukemic samples. The analysis revealed a 10 Mb gain on 19q13.32 in the sALL, absent in the preleukemic specimen. These data provide insight into the dynamics of leukemogenesis in secondary leukemia with MLL rearrangement.

• MeSH
• akutní promyelocytární leukemie genetika   metabolismus   patologie   terapie   MeSH
• cytogenetické vyšetření MeSH
• financování organizované MeSH
• forkhead transkripční faktory genetika   metabolismus   MeSH
• fúze genů MeSH
• genová přestavba MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• lidské chromozomy, pár 19 genetika   MeSH
• mladiství MeSH
• myeloidní buňky metabolismus   MeSH
• nádorové biomarkery genetika   metabolismus   MeSH
• nádorové kmenové buňky metabolismus   patologie   MeSH
• pre-B-buněčná leukemie genetika   metabolismus   patologie   terapie   MeSH
• preleukemie genetika   MeSH
• protoonkogenní protein MLL genetika   metabolismus   MeSH
• regulace genové exprese u leukemie MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH