scholarly journals PML Mutation in PML-Rarα Alters PML Nuclear Body Organization and Induces ATRA Resistance in Acute Promyelocytic Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3923-3923 ◽  
Author(s):  
Hong-Hu Zhu ◽  
Congying Wu ◽  
Yujie Sun ◽  
Jiong Hu
Keyword(s):  
Acute Promyelocytic Leukemia ◽  
Single Molecule ◽  
Structural Changes ◽  
Conflicts Of Interest ◽  
Fusion Gene ◽  
Promyelocytic Leukemia ◽  
Response To Therapy ◽  
Nuclear Bodies ◽  
Cross Resistance ◽  
Drug Induced

Abstract Acute promyelocytic leukemia (APL) has become a highly curable disease using target drugs including all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) with or without chemotherapy. However, APL patients with acquiredPML mutationsin PML-RARα had dismal outcomes and showed resistance not only to ATO but also to ATRA.In this study, we confirmed in the clinic that APL patients with mutations in the PML moiety of PML-RARα showed different resistanceto ATRA (cross-resistance). We demonstrated that critical mutations are responsible for this "cross-resistance". Super-resolution microscopy and electron microcopy were employed to examine the fine structural changes of PML/PML-RARα nuclear bodies (NBs) in response to therapy. We observed drug-induced acceleration of NB movement, which was absent in the mutant cells. Furthermore, NB doublets were revealed, and fusion events were captured upon drug treatment. We proposed that SUMOylation contributed to increased NB dynamics, leading to more fusion incidents and thustaking functional NBs for oncoprotein degradation. Different protein density in the mutant NBswas identified by single molecule quantification, indicating reduced permeability and recruitment of clients. Taken together, our results revealed that critical sites in the PML moiety of the PML-RARα fusion gene disrupted NB scaffold organization and perturbed fusion protein degradation in response to ATRA.Our work will largely improve the mechanistic understandings of APL pathology and therapy and will shed new light on unveiling the structure and function of PML NBs. Disclosures No relevant conflicts of interest to declare.

Acute Promyelocytic Leukemia Harboring STAT5b-RARα Fusion Gene and G596V Mutation in the Stat5b SH2 Domain of the Fusion Gene.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4227-4227 ◽  
Author(s):  
Eisaku Iwanaga ◽  
Miki Nakamura ◽  
Tomoko Nanri ◽  
Toshiro Kawakita ◽  
Naofumi Matsuno ◽  
...  
Keyword(s):  
Dna Repair ◽  
Missense Mutation ◽  
Acute Promyelocytic Leukemia ◽  
Clinical Features ◽  
Fusion Gene ◽  
Sh2 Domain ◽  
Promyelocytic Leukemia ◽  
Response To Therapy ◽  
Chromosome 17 ◽  
Marrow Cells

Abstract Most patients with acute promyelocytic leukemia (APL) exhibit a characteristic t(15;17) translocation that fuses the PML on 15q22 to the RARα on 17q12. In a small subset of APL, RARα fuses to several other genes including the PLZF on 11q23, NPM1 on 5q35, NUMA1 on 11q13, STAT5b on 17q11, and PRKAR1α on 17q23. The STAT5b-RARα chimeric protein was delocalized from the cytoplasm to the nucleus, where it displayed a microspeckled pattern, implicating that this APL might result from dysregulation of the JAK/STAT5 signal transduction pathway. However, only two patients with APL harboring STAT5b-RARα fusion gene have been reported, and clinical features and response to therapy as well as the pathogenesis in this subgroup remain to be determined. We examined 8 PML-RARα-negative APL patients for the presence of the above alternative fusion genes by RT-PCR. We here present the third patient with APL harboring a STAT5b-RARα fusion gene and a missense mutation G596V in the SH2 domain of the STAT5b. A 41-year old Japanese man admitted to our hospital because of petechiae, fever and leukocytosis (77.8 x 109/L). His promyelocytes were relatively mature with dense nuclei and abundant azurophilic granules, while faggot cells were observed. Promyelocytes were positive for CD13 and CD33, but negative for CD34, CD117 or HLA-DR, consistent with APL cells. Karyotype analysis of the bone marrow cells revealed 47, XY,del(9)(q?),add(17)(q12),+mar1[3]/48, XY,idem,+mar1[17]. Activity of α2 plasmin inhibitor was 16%, and FDP was 344.0 μg/mL (< 5.0 μg/mL). The patient was diagnosed to have APL and DIC with fibrinolysis. He achieved a complete remission after one course of chemotherapy and all-trans retinoic acid (ATRA) although the sign of ATRA-induced granulocytic differentiation was not observed. Sequence analysis of the STAT5b-RARα transcript disclosed that the STAT5-RARα fusion gene corresponded to those of previously reported case of STAT5b-RARα-positive APL. Abnormalities of chromosome 17 and resistance to ATRA were commonly observed in 3 patients harboring STAT5b-RARα. Interestingly, there was an additional missense mutation (G596V) within the STAT5b SH2 domain of the STAT5b-RARα gene. Neither STAT5b-RARα fusion gene nor G596V was detected in marrow cells during remission. As the SH2 domain plays an important role in the activation of STAT proteins and the G596 substituted amino acid is highly conserved in the SH2 domain-containing proteins, it would be interesting to analyze the STAT5b and STAT5b-RARα protein harboring G596V mutation. In addition, G596V mutant clone dominate before treatment and wild type subclone was not detected. G596V mutation may occur at an early phase of leukemogenesis or may acquire dominant proliferation during development of APL. STAT5 appears to upregulate DNA repair protein RAD51. One can assume that activated STAT5b-RARα disrupts DNA repair process and results in genomic instability. Further investigations are needed to understand the molecular pathogenesis and clinical features of STAT5b-RARα-positive APL.

The Acute Promyelocytic Leukemia-Oncoprotein PML-Raralpha Blocks Senescence and Disrupts The Atrx/Daxx Chromatin Remodeling Complex To Promote Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1267-1267
Author(s):  
Katharina Korf ◽  
Harald Wodrich ◽  
Alexander Haschke ◽  
Ron M. Evans ◽  
Thomas M. Sternsdorf
Keyword(s):  
Bone Marrow ◽  
Acute Promyelocytic Leukemia ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Promyelocytic Leukemia ◽  
Nuclear Bodies ◽  
Cell Cycle Regulators ◽  
Murine Bone Marrow ◽  
Pml Nuclear Bodies

Abstract Although Acute Promyelocytic Leukemia (APL) has become a curable disease due to in-depth understanding of the underlying molecular processes, its investigation has provided unique and valuable insights into the processes involved in leukemogenesis. Therefore we use it as a model disease. 99% of APL-patients express a PML-RAR fusion protein. While involvement of RAR has proven indispensable for oncogenicity, the role of the PML domain is far less clear. In our previous study (Sternsdorf et al., Cancer Cell, 2006) we found that substitution of PML with heterologous self-interaction domains suffices to induce leukemias, but drastically decreases oncogenic potency of the resulting fusion proteins. In this study, we have chosen the inverse strategy: we have modified the PML domain to create a more active artificial model oncoprotein by adapting PR to its biological environment: As the typical model organism for APL studies is the mouse, we have replaced the human PML domain with the murine PML domain. This oncoprotein (mPR) creates APL-type leukemias in mice with higher penetrance and shorter latency than its human counterpart, hPR. We have used this system to study immediate early effects of expression of the model oncoprotein. While proliferating murine bone marrow cells go into senescence ex vivo, expression of mPR prevents this and robustly immortalizes murine bone marrow from every mouse strain tested so far. Senescence-associated upregulation of the cell-cycle regulators p21 and p19 was efficiently blocked by mPR expression. In mouse cells, mPR exhibits higher potency in disrupting the PML-associated Daxx/ATRX complex than hPR. Knockdown of ATRX, but not Daxx ameliorated ATRA-induced growth suppression and p21 upregulation in the human APL model cell line NB4. These data suggest, that PML-RAR promotes leukemogenesis by disrupting the Daxx/ATRX complex, which assembles at PML nuclear bodies during the onset of senescence. Disclosures: No relevant conflicts of interest to declare.

New Translocation (7:17) In Variant Acute Promyelocytic Leukemia With ATRA Resistance

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4963-4963 ◽  
Author(s):  
Carolina Guillen ◽  
Lorena Mardones ◽  
Jorge Sánchez-Calero ◽  
Esther Jaro ◽  
Rocio Salgado ◽  
...  
Keyword(s):  
Acute Promyelocytic Leukemia ◽  
Peripheral Blood ◽  
Conflicts Of Interest ◽  
Fusion Gene ◽  
Previous History ◽  
Coronary Bypass ◽  
Hemoglobin Concentration ◽  
Promyelocytic Leukemia ◽  
Laboratory Evaluation ◽  
Fusion Partner

Abstract Background Acute promyelocytic leukemia (APL) is characterized by pathologic promyelocytes, chromosomal translocations t(15:17) (q22; q21) and clinical and cytological response to all-transretinoic acid (ATRA). A significant minority of patients with APL have variant translocations involving RARα gene with a different partner, not involving PML. These APL variant translocations may or not respond to ATRA treatment. Case report A routine laboratory evaluation, before minor surgery, revealed leukocytosis, thrombocytopenia and blasts presence in peripheral blood (PB), in an otherwise asymptomatic 70-year-old man. He had a previous history of hypertension, dyslipidemia, ischemic heart disease, double coronary bypass and prostatectomy for non-malignant prostatic hypertrophy. Peripheral blood (PB) count: hemoglobin concentration 12g/dL, platelet count: 21x109/L and white blood cell count (WBC): 35x109/L. Peripheral blood smear: myelemia exhibiting 74% blasts (including myeloid blast and promyelocytes) with fine chromatin pattern, heterogeneous and frequently convoluted nuclei and one to three prominent nucleoli. The cytoplasm of these cells was basophilic with scanty purple granules. No Auer rods were found. The basic coagulation tests were normal(INR, APTT and fibrinogen) but D Dimer was 33.87 µg/ml. Normal biochemistry was shown, except for GGT 85 U/L and lactate dehydrogenase 2244 U/L. Bone marrow (BM) aspirate was unsuccessful (”dry tap”) but the bone trephine revealed an infiltration of 80% myeloid blasts. Cytochemistry: myeloperoxidase stain was deeply positive and chloroacetate and non-specific esterase stains were negative. Flow cytometry immunophenotype on PB was consistent with AML, likely M3 leukemia, with an atypical phenotype (MPO+, CD117+low, CD34+, CD13++, CD45+, CD15-,CD133-, CD33+, HLA-DR+low het , CD5-, CD7-, CD11b- , CD56+het, CD10-, CD8- ,CD4-, CD45RA+, CD19-, CD2-, Glya-, CD71+low, CD38-, CD1a-, CD41-, CD14-). The analysis of the PML/RARα fusion gene, according to standard protocols, was negative. FISH studies showed 2 PML signals and 3 RARα copies, suggesting a possible variant rearrangement of this gene. FISH and molecular biology did not detect transcript for t(15:17), (5:17) or (11:17); so RARα was translocated with a strange partner. Suspecting of a variant APL, the patient was treated with ATRA plus Idarrubicin. After 4 weeks treatment, deep neutropenia was observed but no granulocytic maturation. That suggested us resistance to ATRA. Thus, we changed the treatment to a classical induction scheme for AML. The patient attained cytologic remission, which he mantains so far with conventional chemotherapy. Karyotype study was subsequently performed, identified an unbalanced rearrangement between 7q and 17q. Currently, we are identifying and sequencing the fusion partner of RARα. Conclusion We report a novel case of variant acute promyelocytic leukemia with the karyotype der (7) t(7;17) (q11;q21). The morphology of PB and BM was critical for initial diagnosis and treatment decisions. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The PML/RARα-Regulated MiR-181a/b-Cluster Targets the Tumor Suppressor RASSF1A in Acute Promyelocytic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2195-2195
Author(s):  
Daniela Braeuer-Hartmann ◽  
Jens-Uwe Hartmann ◽  
Dennis Gerloff ◽  
Christiane Katzerke ◽  
Alexander Arthur Wurm ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tumor Suppressor ◽  
Acute Promyelocytic Leukemia ◽  
Conflicts Of Interest ◽  
Fusion Gene ◽  
Promyelocytic Leukemia ◽  
Granulocytic Differentiation ◽  
Nb4 Cells ◽  
Knock Down ◽  
Functional Studies

Abstract In acute promyelocytic leukemia (APL) bearing the translocation t(15;17), all-trans-retinoic acid (ATRA) treatment induces granulocytic maturation and complete remission of leukemia. Several factors are involved in the formation of the leukemic phenotype. Latest studies identified microRNAs as critical players in this network. In a micro array based microRNA screen we could identify the genomically clustered miR-181a and miR-181b as downregulated in the APL cell line NB4 by treatment with pharmacological doses of ATRA. In addition, the expression of the miR-181a/b-cluster was strongly reduced in bone marrow samples of APL patient while ATRA-based therapy. Furthermore, we showed the transcriptional induction of miR-181a and miR-181b by the APL-associated PML-RARα oncogene in vitro and in vivo. In PR9 cells, carrying a zinc-driven PML/RARα construct, and in PML/RARα-knock in mice the expression of the fusion gene leads to upregulation of the microRNA-cluster expression. Analysis of bone marrow samples of APL patients showed an enhanced expression of miR-181a and miR-181b in comparison to AML patient samples with normal karyotype, whereas other AML subgroups show no significant regulation. Based on siRNA experiments we could propose AP-1 and GATA-2 as potential co-activators for the PML/RARα-dependent regulation of the miR-181a/b-cluster. In functional studies in NB4 cells we observed after lentiviral knock down of miR-181a and miR-181b a significant reduction of colony size and number as well as proliferation rate. In contrast, transient overexpression of miR-181a and miR-181b led to an inhibition of ATRA-induced expression of the differentiation marker CD11b. In a microRNA target search we identified the novel ATRA regulated tumor suppressor RASSF1A as a putative target of miR-181a and miR-181b. In functional studies we showed that enforced expression of miR-181a and miR-181b reduces the protein level of RASSF1A by binding to the 3´UTR of RASSF1A mRNA. Accordingly, RASSF1A protein was enriched after knock down of miR-181b. The role of RASSF1A in ATRA induced differentiation was verified by knock down of RASSF1A protein by specific siRNA: Here we could show the reduction of ATRA induced CD11b expression. Overexpression of RASSF1A in NB4 cells strongly induced apoptosis. Additional, we could show by western blot that the miR-181a/b-cluster and RASSF1A modulate cell cycle via regulation of cyclin D1. In conclusion, we identified the miR-181a/b-cluster as an important player in the PML/RARα associated APL. Moreover, we firstly described the miR-181a/b target RASSF1A as a crucial factor in the ATRA activated granulocytic differentiation program in APL. Our data reveal the importance of deregulated microRNA biogenesis in cancer and may provide novel biomarkers and therapeutic targets in myeloid leukemia. Disclosures No relevant conflicts of interest to declare.

scholarly journals Correction: Liquori et al. Acute Promyelocytic Leukemia: A Constellation of Molecular Events around a Single PML-RARA Fusion Gene. Cancers 2020, 12, 624

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3440
Author(s):  
Alessandro Liquori ◽  
Mariam Ibañez ◽  
Claudia Sargas ◽  
Miguel Ángel Sanz ◽  
Eva Barragán ◽  
...  
Keyword(s):  
Acute Promyelocytic Leukemia ◽  
Fusion Gene ◽  
Promyelocytic Leukemia ◽  
Molecular Events

The authors wish to make the following corrections to this paper [...]

Synergic effects of arsenic trioxide and cAMP during acute promyelocytic leukemia cell maturation subtends a novel signaling cross-talk

Blood ◽  
2002 ◽  
Vol 99 (3) ◽  
pp. 1014-1022 ◽  
Author(s):  
Qi Zhu ◽  
Ji-Wang Zhang ◽  
Hai-Qing Zhu ◽  
Yu-Lei Shen ◽  
Maria Flexor ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Arsenic Trioxide ◽  
Acute Promyelocytic Leukemia ◽  
Cross Talk ◽  
Fusion Gene ◽  
Leukemia Cell ◽  
Promyelocytic Leukemia ◽  
Dependent Manner ◽  
Induced Differentiation

Abstract Acute promyelocytic leukemia (APL) is characterized by the specific chromosome translocation t(15;17) with promyelocytic leukemia-retinoic acid receptor-α (PML-RARA) fusion gene and the ability to undergo terminal differentiation as an effect of all-trans retinoic acid (ATRA). Recently, arsenic trioxide (As2O3) has been identified as an alternative therapy in patients with both ATRA-sensitive and ATRA-resistant APL. At the cellular level, As2O3 triggers apoptosis and a partial differentiation of APL cells in a dose-dependent manner; both effects are observed in vivo among patients with APL and APL animal models. To further explore the mechanism of As2O3-induced differentiation, the combined effects of arsenic and a number of other differentiation inducers on APL cell lines (NB4 and NB4-R1) and some fresh APL cells were examined. The data show that a strong synergy exists between a low concentration of As2O3 (0.25 μM) and the cyclic adenosine monophosphate (cAMP) analogue, 8-CPT-cAMP, in fully inducing differentiation of NB4, NB4-R1, and fresh APL cells. Furthermore, cAMP facilitated the degradation of As2O3-mediated fusion protein PML-RARα, a process considered to play a key role in overcoming the differentiation arrest of APL cells. On the other hand, cAMP could significantly inhibit cell growth by modulating several major players in G1/S transition regulation. Interestingly, H89, an antagonist of protein kinase A, could block the differentiation-inducing effect of As2O3potentiated by cAMP. These results thus support the existence of a novel signaling cross-talk for APL maturation, which may deepen understanding of As2O3-induced differentiation in vivo, and thus furnish insights for new therapeutic strategies.

scholarly journals Remission in Patients with Acute Promyelocytic Leukemia Treated with Arsenic Trioxide (varitrinox) As the First Line in Colombia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 3-3
Author(s):  
Gustavo Milone ◽  
Samuel Sarmiento Doncel ◽  
Carol Agudelo Rico ◽  
Fabiola Vizcarra Reyes ◽  
Gina Alejandra Diaz Mosquera ◽  
...  
Keyword(s):  
High Risk ◽  
Arsenic Trioxide ◽  
Acute Promyelocytic Leukemia ◽  
Conflicts Of Interest ◽  
Promyelocytic Leukemia ◽  
Remission Induction ◽  
Intermediate Risk ◽  
Newly Diagnosed ◽  
First Line ◽  
Risk Patients

Acute promyelocytic leukemia (APL) is a subtype of Acute Myeloid Leukemia (AML) in which a chromosomal translocation t (15; 17) (q22; q12) is generated by fusing produces a hybrid PML / RARα gene, generating an altered signal . The combination of transretinoic acid (ATRA) plus arsenic trioxide (ATO) has been shown to be superior to ATRA plus chemotherapy in the treatment of newly diagnosed standard risk patients with acute promyelocytic leukemia (APL) in several countries. The objective of the present study is to describe the frequency of remission in patients with acute promyelocytic leukemia who were administered as a first line Arsenic Trioxide (varitrinox) during the period from November 2017 to June 2020 in Colombian patients. Methods: Retrospective observational and descriptive study of 12 patients diagnosed with acute promyelocytic leukemia treated with ATO Arsenic trioxide (Varitrinox) as first line, the source of information was provided by the treating hematologists (medical records) by filling out the technical concept format. Active pharmacovigilance scientist in Colombia, this format keeps the identification information of the patient anonymized and the confidentiality of the data is guaranteed as well as compliance with the rules of good clinical practice. Results: Twelve patients with age range between 22 and 69 years with a median age of 34.0 were analyzed. It was found in the analysis that 100% had induction hematologic remission with a median of 45 days. 75% of patients received ATO + ATRA and were at low and intermediate risk, the remaining 25% received ATRA + ATO + Chemotherapy and were at high risk, and intermediate risk. 91.7% of molecular remission in consolidation was obtained and it was measured in cycle 3 by means of PCR (undetectable), 8.3% (n = 1) was positive 3% and is finishing consolidation. Regarding the most frequent adverse events, intravascular coagulation (n = 9), neutropenia (n = 6) and thrombocytopenia (n = 6) were observed. 75% of patients are disease-free, 16.7% are on maintenance (they received ATO + ATRA + Induction chemotherapy) and 8.3% are on consolidation. So far, none of the patients under study have died. Conclusions: Our results support the use of ATO (Varitrinox) in newly diagnosed APL patients (as first line), as a care strategy for low, intermediate and high risk patients. The role of ATRA-ATO is guaranteed in other studies where they manage patients of different risks. Key words: Arsenic trioxide, leukemia promyelocytic acute, leukemia myeloid acute, remission induction, tretinoin. Disclosures No relevant conflicts of interest to declare.

PML-RARalpha fusion gene transcripts and biological features in acute promyelocytic leukemia patients

2006 ◽  
Vol 28 (2) ◽  
pp. 126-129 ◽  
Author(s):  
R. A. M. MELO ◽  
J. F. VASCONCELLOS ◽  
F. C. B. C. MELO ◽  
C. G. F. MACHADO ◽  
T. M. S. LACERDA ◽  
...  
Keyword(s):  
Acute Promyelocytic Leukemia ◽  
Fusion Gene ◽  
Promyelocytic Leukemia ◽  
Biological Features ◽  
Gene Transcripts

scholarly journals PLZF-RARα, NPM1-RARα, and Other Acute Promyelocytic Leukemia Variants: The PETHEMA Registry Experience and Systematic Literature Review

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1313 ◽  
Author(s):  
Marta Sobas ◽  
Maria Carme Talarn-Forcadell ◽  
David Martínez-Cuadrón ◽  
Lourdes Escoda ◽  
María J. García-Pérez ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Complete Remission ◽  
Acute Promyelocytic Leukemia ◽  
Fusion Gene ◽  
Retinoic Acid Receptor ◽  
Promyelocytic Leukemia ◽  
High Relapse Rate ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Shed Light

It has been suggested that 1–2% of acute promyelocytic leukemia (APL) patients present variant rearrangements of retinoic acid receptor alpha (RARα) fusion gene, with the promyelocytic leukaemia zinc finger (PLZF)/RARα being the most frequent. Resistance to all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) has been suggested in PLZF/RARα and other variant APLs. Herein, we analyze the incidence, characteristics, and outcomes of variant APLs reported to the multinational PETHEMA (Programa para el Tratamiento de Hemopatias Malignas) registry, and we perform a systematic review in order to shed light on strategies to improve management of these extremely rare diseases. Of 2895 patients with genetically confirmed APL in the PETHEMA registry, 11 had variant APL (0.4%) (9 PLZF-RARα and 2 NPM1-RARα), 9 were men, with median age of 44.6 years (3 months to 76 years), median leucocytes (WBC) 16.8 × 109/L, and frequent coagulopathy. Eight patients were treated with ATRA plus chemotherapy-based regimens, and 3 with chemotherapy-based. As compared to previous reports, complete remission and survival was slightly better in our cohort, with 73% complete remission (CR) and 73% survival despite a high relapse rate (43%). After analyzing our series and performing a comprehensive and critical review of the literature, strong recommendations on appropriate management of variant APL are not possible due to the low number and heterogeneity of patients reported so far.

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