Progression To Acute Leukemia Research Articles

The Gut Microbiome and Acute Leukemia: Implications for Early Diagnostic and New Therapies.

Acute leukemia (AL), one of the hematological malignancies, shows high heterogeneity. Tremendous progresses are achieved in treating AL with novel targeted drugs and allogeneic hematopoietic stem cell transplantation, there are numerous issues including pathogenesis, early diagnosis, and therapeutic efficacy of AL to be solved. In recent years, an increasing number of studies regarding microbiome have shed more lights on the role of gut microbiota in promoting AL progression. Mechanisms related to the role of gut microbiota in enhancing AL genesis are summarized in the present work, especially on critical pathways like leaky gut, bacterial dysbiosis, microorganism-related molecular patterns, and bacterial metabolites, resulting in AL development. Additionally, the potential of gut microbiota as the biomarker for early AL diagnosis is discussed. It also outlooks therapies targeting gut microbiota for preventing AL development.

Prevention and Health Benefits of Prebiotics, Probiotics and Postbiotics in Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in children, comprising 75-85% of cases. Aggressive treatment of leukemias includes chemotherapy and antibiotics that often disrupt the host microbiota. Additionally, the gut microbiota may play a role in the development and progression of acute leukemia. Prebiotics, probiotics, and postbiotics are considered beneficial to health. The role of prebiotics in the treatment and development of leukemia is not well understood, but inulin can be potentially used in the treatment of leukemia. Some probiotic bacteria such as Lactobacillus shows anticancer activity in in vitro studies. Additionally, Bifidobacterium spp., as a consequence of the inhibition of growth factor signaling and mitochondrial-mediated apoptosis, decrease the proliferation of cancer cells. Many bacterial metabolites have promising anticancer potential. The available research results are promising. However, more research is needed in humans, especially in the child population, to fully understand the relationship between the gut microbiota and acute leukemia.

A novel Menin-MLL1 inhibitor, DS-1594a, prevents the progression of acute leukemia with rearranged MLL1 or mutated NPM1

BackgroundMixed lineage leukemia 1-rearranged (MLL1-r) acute leukemia patients respond poorly to currently available treatments and there is a need to develop more effective therapies directly disrupting the Menin‒MLL1 complex. Small-molecule–mediated inhibition of the protein‒protein interaction between Menin and MLL1 fusion proteins is a potential therapeutic strategy for patients with MLL1-r or mutated-nucleophosmin 1 (NPM1c) acute leukemia. In this study, we preclinically evaluated the new compound DS-1594a and its salts.MethodsWe evaluated the preclinical efficacy of DS-1594a as well as DS-1594a·HCl (the HCl salt of DS-1594a) and DS-1594a·succinate (the succinic acid salt of DS-1594a, DS-1594b) in vitro and in vivo using acute myeloid leukemia (AML)/acute lymphoblastic leukemia (ALL) models.ResultsOur results showed that MLL1-r or NPM1c human leukemic cell lines were selectively and highly sensitive to DS-1594a·HCl, with 50% growth inhibition values < 30 nM. Compared with cytrabine, the standard chemotherapy drug as AML therapy, both DS-1594a·HCl and DS-1594a·succinate mediated the eradication of potential leukemia-initiating cells by enhancing differentiation and reducing serial colony-forming potential in MLL1-r AML cells in vitro. The results were confirmed by flow cytometry, RNA sequencing, RT‒qPCR and chromatin immunoprecipitation sequencing analyses. DS-1594a·HCl and DS-1594a·succinate exhibited significant antitumor efficacy and survival benefit in MOLM-13 cell and patient-derived xenograft models of MLL1-r or NPM1c acute leukemia in vivo.ConclusionWe have generated a novel, potent, orally available small-molecule inhibitor of the Menin-MLL1 interaction, DS-1594a. Our results suggest that DS-1594a has medicinal properties distinct from those of cytarabine and that DS-1594a has the potential to be a new anticancer therapy and support oral dosing regimen for clinical studies (NCT04752163).

Novel therapeutics in myeloproliferative neoplasms: beyond JAK inhibitors

The discovery of driver genes such as JAK2 in myeloproliferative neoplasms (MPN) led to a better understanding of MPN pathogenesis as a constitutive activation of the JAK/STAT signal. Following these findings, several types of JAK inhibitors have been developed. Ruxolitinib, a JAK1/2 inhibitor licensed for polycythemia vera and myelofibrosis, demonstrated efficacy in regulating hematocrit levels, lowering spleen volume, and relieving MPN-related symptoms. However, some patients with myelofibrosis are refractory to JAK inhibitors, and some are intolerant due to cytopenia. Furthermore, JAK inhibitors did not slow the progression of acute leukemia, indicating the need for new therapeutic methods for myelofibrosis. Novel medicines, including BCL inhibitor, MDM2 inhibitor, LSD1 inhibitor, PI3K inhibitor, BET inhibitor and telomerase inhibitor, are presently being evaluated in clinical studies for myelofibrosis with the potential to enhance clinical outcomes.

Serum Tumor Necrosis Factor-Alpha Levels in Acute Leukemia and Its Prognostic Significance.

IntroductionTumor necrosis factor-alpha (TNF-α) is a pleiotropic cytokine that facilitates malignant cells in immune evasion, survival, and treatment resistance by generating a favorable milieu for them. It is shown to be ectopically produced by malignant/leukemic and immune cells in the tumor microenvironment, providing a tumor-supportive environment and playing an important part in the establishment and progression of malignant cells. It is linked to hyperleukocytosis, high blast count, and poor clinical outcomes in acute leukemia (AL). Considering the varied role and different expression patterns of tumor necrosis factor-alpha in acute leukemia and its clinical relevance, the present study was planned to monitor the level of tumor necrosis factor-alpha in patients with acute leukemia and its correlation with disease outcome. The aim of this study was to monitor the level of tumor necrosis factor-alpha in patients with acute leukemia at the time of diagnosis and after induction chemotherapy.Material and methodsThe study included cases classified as acute leukemia based on morphological examination, bone marrow analysis, and flow cytometry. In all patients with acute leukemia (n = 90) and controls (n = 10), the serum tumor necrosis factor-alpha level was measured using a Diaclone Human ELISA kit (Diaclone, Besancon, France) (solid phase sandwich ELISA) at diagnosis and after induction chemotherapy.ResultsTumor necrosis factor-alpha levels were substantially higher in T-acute lymphoblastic leukemia (T-ALL) cases, followed by acute myeloid leukemia (AML) and B-acute lymphoblastic leukemia (B-ALL), at the time of diagnosis, compared to the control. A significant reduction in serum tumor necrosis factor-alpha level was seen in patients with acute leukemia after induction phase chemotherapy (P < 0.05). Tumor necrosis factor-alpha levels were considerably reduced (P < 0.001) in the majority of acute leukemia cases after the induction phase, while high tumor necrosis factor-alpha levels were positively correlated with incomplete remission status in the remaining cases.ConclusionTumor necrosis factor-alpha is involved in the progression of acute leukemia and its relapse. High levels of tumor necrosis factor-alpha are linked to leukocytosis, high blast counts, and worse survival in patients with acute leukemia. Monitoring of tumor necrosis factor-alpha may be helpful in patients with acute leukemia in view of available antitumor necrosis factor-alpha therapy.

Age Is Not a Predictive Marker in Molecularly Annotated Elderly Patients with Myelofibrosis Treated with Ruxolitinib: a Multicenter Study on 277 Patients.

Introduction. Ruxolitinib (RUX) is a JAK1/2 inhibitor that may control myelofibrosis (MF)-related splenomegaly and symptoms and can be prescribed regardless of age. Aging correlates with clinically impaired prognosis probably due to biologically increased molecular complexity. However, assessment of efficacy/safety of RUX and correlation with clonal architecture in elderly MF patients (pts) is relatively unknown.Aims. To report the clinical outcome of 277 pts with WHO-defined MF treated with RUX when aged ≥65 yrs. To correlate molecular status assessed by targeted sequencing of 30 genes known to be involved in myeloid disorders with response to therapy and survival.Methods. A clinical database was created in 20 European Hematology Centers. Retrospective data on 487 MF pts treated with RUX according to prescribing information from Jan 2011 to Jun 2016 were collected. Spleen (SR) and Symptoms (SyR) Response to RUX were evaluated according to the 2013 IWG-MRT criteria. Survival was calculated from the start of RUX. Event-free survival (EFS) included progression to acute leukemia (AL), death and RUX discontinuation. Peripheral blood (PB) granulocytes-derived DNA was extracted and processed according to the “Myeloid Solution” (SOPHIA GENETICS) assay on the MiSeq Illumina platform. Variants were pre-classified as potentially pathogenic by SOPHiATM Artificial Intelligence. Output data was analyzed by Sophia DDM v3 software.Results. A total of 277 out of 487 pts (46.6%) started RUX when aged ≥65 yrs. Compared to elderly (age 65-74) pts, very elderly (≥ 75 yr) pts had a higher Charlson Comorbidity Index and a lower platelet count, thus started RUX at lower doses (Table 1). At 6 mos, SR and SyR were achieved by 35.9% and 83.7% of 209 and 221 evaluable pts, respectively. In the first 6 mos, anemia/thrombocytopenia/infections ≥G2 were observed in 33.6%, 21.7% and 29.2% of the 277 pts, respectively. The only feature independently associated with increased infectious risk was a history of previous infection. Evolution into AL occurred in 22 pts. Overall, 110 pts discontinued RUX after a median time of 12.5 mos. Importantly, the rate of toxicities, responses, and disease evolution was not influenced by age. After a median follow-up of 19.5 mos, 65 pts died because of progression of myelofibrosis (40%), heart disease (10.8%), infections (13.8%), AL (15.4%), hemorrhage/thrombosis (7.7%) or transplant-associated toxicity (4.6%). Older age and Body Mass Index <21 (first quartile) was significantly associated with worse survival (p=0.02).NGS will be performed on 100/277 pts with available PB samples at RUX start. Preliminary data on 48 elderly pts (median age, 72.5 yrs) showed that all pts had a mutation in ≥1 gene (Fig. 1). A total of 523 variants have been identified so far. Only 297 (57%) variants were considered potentially pathogenetic. Four genes (BRAF, FLT3, HRAS, WT1) investigated in the NGS panel were never mutated. Recurrent mutations with potential pathogenic impact included TET2 (20,5%), ASXL1 (14%), SETBP1 (7,7%), EZH2 (6,7%), DNMT3A (4,7%), KIT (3,7%). The percentages of pts with pathogenetic variants for the most recurrently mutated genes were: ASXL1 (50%), TET2 (50%), DNMT3A (22,9%), EZH2 (25%), SETBP1 (21%), KIT (10,4%). At least one high molecular risk (HMR) pathogenetic mutation was present in 61% of pts; 37% had ≥2 HMR mutations. The most frequently mutated HMR genes were ASXL1 and EZH2, that co-occurred in 22% of the cases. HMR status was significantly associated with PMF and larger (>10 cm) spleen length (p=0.04). Additionally, patients with EZH2 mutation and ≥3 variants showed a lower baseline hemoglobin and platelet count (respectively p=0.04 and p=0.03). Molecular status (HMR, ≥2 HMR mutations, ≥3 variants and ASXL1- or EZH2-mutations) was investigated for association with clinical responses/outcome parameters. Preliminary data showed a trend for association of HMR+ and ≥3 variants with worse EFS and leukemia-free survival.Discussion. Since response/toxicity rates were not influenced by age, older age should not be a limitation for RUX therapy. The assessment of comorbidities, nutrition status and infectious history may identify specific pts fragilities. The cohort of molecularly annotated pts will be further enriched. However, we have so far observed a high molecular complexity that did not seem to affect responses and survival in the elderly.LC and FHH equally contributed. [Display omitted] DisclosuresBonifacio:Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Abruzzese:Novartis: Consultancy; Pfizer: Consultancy; BMS: Consultancy; Incyte: Consultancy. Tiribelli:Incyte: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Breccia:Bristol Myers Squibb: Consultancy; Novartis: Consultancy; Incyte: Consultancy; Pfizer: Consultancy. Cavazzini:Pfizer: Consultancy; Incyte: Consultancy; Bristol-Meyers Squibb: Consultancy; Novartis: Consultancy. Crugnola:Celgene: Honoraria; BMS: Honoraria; Novartis: Honoraria. Martinelli:Amgen: Consultancy; Celgene: Consultancy; Pfizer: Consultancy; Ariad/Incyte: Consultancy; Johnson&Johnson: Consultancy; Roche: Consultancy.

Expression Levels of Il-6 and Il-18 in Acute Myeloid Leukemia and Its Relation with Response to Therapy and Acute GvHD After Bone Marrow Transplantation.

Cytokines seem to play a crucial role in physiological and pathological conditions of acute myeloid leukemia (AML). The aim of this study was to evaluate the expression levels of interleukins-6 (IL-6) and IL-18 in patients with AML and its correlation with response to therapy and graft versus host disease (GvHD) after bone marrow transplantation. The expression levels of IL-6 and IL-18 genes were done in all patients and compared with matched control. Complete remission (CR) was used for evaluation of the effects of these cytokines on response to treatment in patients group. The expression level of these cytokines was also evaluated in patients who underwent bone marrow transplantation and experienced acute GvHD in compare with patients without aGvHD. Il-6 gene expression level was significantly higher in these patients in comparison with control but Il-18 gene expression level was not statistically significant compared to control group. Il-6 and also Il-18 expression levels were significantly higher in patients without a response to treatment according to CR compared to patient's whit response to treatment as well as patients experienced aGvHD after bone marrow transplantation. IL-6 and Il-18 are important markers in the progression of the disease and could be considered as a prognostic marker in acute leukemia. It is recommended that more studies with larger study groups and more involved cytokines are needed for more evaluation of the cytokine roles in pathophysiology and progression of acute leukemia.

HOTAIR expression and prognostic impact in acute myeloid leukemia patients

BackgroundAcute myeloid leukemia (AML) is a disorder characterized by a rapid onset of symptoms attributable to bone marrow failure due to clonal proliferation of primitive hematopoietic stem cells or progenitor cells. Epigenetic abnormalities play an important role in the development and progression of acute leukemia. Long non-coding ribonucleic acid (lncRNA) plays an important role in epigenetic regulation. Homeobox (Hox) transcript antisense intergenic RNA (HOTAIR) is a lncRNA which has been determined to be a negative prognostic indicator in various solid-tumor patients. However, its role in hematopoietic tumors as AML is to be assessed. This study aimed at measuring lncRNA HOTAIR expression level on bone marrow (BM) mononuclear cells in newly diagnosed AML patients and correlating its expression with their outcome and different prognostic variables. This provides new prospective for a novel marker involved in development and progression of AML which can be used as a diagnostic marker and a target of therapy. The current study included 65 subjects divided into 35 newly diagnosed AML adult patients (before initiation of chemotherapy) and 30 non-leukemic adult patients who are candidates for BM aspiration for causes other than hematological malignancies as immune thrombocytopenic purpura and hypersplenism as controls. HOTAIR expression was measured on BM mononuclear cells by quantitative reverse transcription polymerase chain reaction (qRT-PCR).ResultsHOTAIR expression was found to be significantly upregulated in AML patients (probability (p) value = 0.000) and it can be used as a diagnostic biomarker of AML as confirmed by a significant difference between cases and controls using receiver operating characteristic curve (ROC) analysis. However, it was not significantly correlated with event free survival (EFS) or prognostic variables.ConclusionThis study showed that the expression of HOTAIR is upregulated in de novo AML patients and can be used as a diagnostic marker. However, highly expressed HOTAIR is not associated with poor prognosis.

Vasculitis associated with myelodysplastic syndrome and chronic myelomonocytic leukemia: French multicenter case-control study

IntroductionOur objective was to evaluate characteristics, treatment and outcome of vasculitis associated with myelodysplastic syndrome (MDS) and chronic myelomonicytic leukemia (CMML) Patients and MethodsRetrospective descriptive analysis of MDS/CMML-related vasculitis and comparison with MDS/CMML patients without dysimmune features. ResultsSeventy patients with vasculitis and MDS/CMML were included, with median age of 71.5 [21–90] years and male/female ratio of 2.3. Vasculitis was diagnosed prior to MDS/CMML in 31 patients (44%), and after in 20 patients. In comparison with MDS/CMML without autoimmune/inflammatory features, vasculitis with MDS/MPN showed no difference in MDS/CMML subtypes distribution nor International Prognostic Scoring System and CMML-specific prognostic (IPSS/CPSS) scores. Vasculitis subtypes included Giant cell arteritis in 24 patients (34%), Behçet's-like syndrome in 11 patients (20%) and polyarteritis nodosa in 6 patients (9%). Glucocorticoids (GCs) were used as first-line therapy for MDS/CMML vasculitis in 64/70 patients (91%) and 41 (59%) received combined immunosuppressive therapies during the follow-up. After a median follow-up of 33.2 months [1–162], 31 patients (44%) achieved sustained remission. At least one relapse occurred in 43 patients (61%). Relapse rates were higher in patients treated with conventional Disease Modifying Anti-Rheumatic Drug (DMARDs) (odds ratio 4.86 [95% CI 1.38 - 17.10]), but did not differ for biologics (odds ratio 0.59 [95% CI 0.11–3.20]) and azacytidine (odds ratio 1.44 [95% CI 0.21–9.76]) than under glucocorticoids. Overall survival in MDS/CMML vasculitis was not significantly different from MDS/CMML patients without autoimmune/inflammatory features (p = 0.5), but acute leukemia progression rates were decreased (log rank <0.05). ConclusionThis study shows no correlation of vasculitis diagnoses with subtypes and severity of MDS/CMML, and no significant impact of vasculitis on overall survival. Whereas conventional DMARDs seem to be less effective, biologics or azacytidine therapy could be considered for even low-risk MDS/CMML vasculitis.

ISSUE HIGHLIGHTS - July 2020.

ISSUE HIGHLIGHTS - July 2020.

Role of microRNA dysregulation in childhood acute leukemias: Diagnostics, monitoring and therapeutics: A comprehensive review.

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of genes by sequence-specific binding to mRNA to either promote or block its translation; they can also act as tumor suppressors (e.g., let-7b, miR-29a, miR-99, mir-100, miR-155, and miR-181) and/or oncogenes (e.g., miR-29a, miR-125b, miR-143-p3, mir-155, miR-181, miR-183, miR-196b, and miR-223) in childhood acute leukemia (AL). Differentially expressed miRNAs are important factors associated with the initiation and progression of AL. As shown in many studies, they can be used as noninvasive diagnostic and prognostic biomarkers, which are useful in monitoring early stages of AL development or during therapy (e.g., miR-125b, miR-146b, miR-181c, and miR-4786), accurate classification of different cellular or molecular AL subgroups (e.g., let-7b, miR-98, miR-100, miR-128b, and miR-223), and identification and development of new therapeutic agents (e.g., mir-10, miR-125b, miR-203, miR-210, miR-335). Specific miRNA patterns have also been described for commonly used AL therapy drugs (e.g., miR-125b and miR-223 for doxorubicin, miR-335 and miR-1208 for prednisolone, and miR-203 for imatinib), uncovering miRNAs that are associated with treatment response. In the current review, the role of miRNAs in the development, progression, and therapy monitoring of pediatric ALs will be presented and discussed.

Downregulation of Mir-142 Promotes Leukemia Growth in Philadelphia Chromosome-Positive (Ph+) Acute Lymphoblastic Leukemia (ALL): A Possible Novel Therapeutic Target?

The Philadelphia (Ph) chromosome or t(9;22) results in the generation of a fusion gene, namely BCR/ABL1, which encodes a chimeric protein with aberrant tyrosine kinase activity that drives leukemia cell growth and survival. This molecular/cytogenetic aberration occurs in ~20%-30% of ALL cases and confers poor prognosis. Ph+ ALL patients (pts) are often referred for allogeneic hematopoietic stem cell transplantation (alloHCT), although more recently BCR-ABL-specific tyrosine-kinase inhibitors (TKIs) and immunotherapeutic approaches seemingly induced long-term remission in some patients. Nevertheless, it is still a challenge to determine which Ph+ ALL of the pts could be treated more conservatively without alloHCT. Thus identification of new prognostic biomarkers and/or therapeutic targets may be helpful. Regulation of short non-coding microRNAs(miRNAs) associated with initiation and progression of acute leukemia has been reported. miR-142(both miR-142-3p and miR-142-5p) is expressed at a relatively high level in hematopoietic tissue, and plays a role in myeloid lineage differentiation. In fact, low miR-142-3p expression was associated with myeloid differentiation failure, and miR-142 mutations was reported to promote acute myeloid leukemia (AML). More recently, Kramer et al demonstrated a role of miR-142 in lymphopoiesis by showing that miR-142 deficiency impaired B cell production in a miR-142 knock-out(ko) mouse model (Blood. 2015).Here, we first investigated if miR-142 levels were altered in ALL pts. Analysis of a publically available miRNA expression dataset(GSE23024) showed lower level of miR-142-3p, but not miR-142-5p in Ph+ ALL pts(n=10) vs. healthy donors(n=7;p=0.0093); while no significant differences were observed in Ph- pre-B ALL pts(n=61) vs. healthy donors (n=7). In ALL Tg(P190-BCR/ABL) transgenic mice(Ph+ ALL; Nature. 1990), we found bone marrow (BM) miR-142-3p level to be ~2.3-fold lower than those in the wild-type (wt) controls(p=0.036). Compared to wt mice, Ph+ ALL mice showed significantly lower miR-142-3p level in all the immunophenotypically identified BM lymphoid subpopulations, including progenitor B (pro-B, B220+CD19+CD43+IgM-,~19.1-fold lower,p<0.0001), precursor B (pre-B, B220+CD19+CD43-IgM-,~9.7-fold lower, p<0.0001), and other immature B (B220lowCD19+CD43-IgM+, ~2.4-fold lower, p<0.001) cells, except for mature B (B220highCD19+CD43-IgM+) cells. Ph+ ALL mice exhibited a miR-142-3p gradient expression pattern following the lymphoid differentiation hierarchy, with the lowest levels found in the pro-B and pre-B populations. These results prompted us to hypothesize that, loss of miR-142 may contribute to primitive B cell expansion possibly due to B cell differentiation blockage in Ph+ ALL mice. To prove this, we crossed miR-142 double knock-out (d-ko)mice with Ph+ ALL mice to generate miR-142(ko)Tg(P190-BCR/ABL) mice. Homozygous miR-142(d-ko)Tg(P190-BCR/ABL) mice were not viable due to an overly aggressive leukemia phenotype. Heterozygous miR-142(wt/ko)Tg(P190-BCR/ABL) mice had evidence of more rapid expansion of pro-B cells in blood(PB; 47.9% vs. 9.8%, p<0.0001), BM (48.2% vs. 13.2%, p<0.01)and spleen(32.3%vs. 4.4%, p<0.01) at 6 weeks old and a significantly reduced survival(median survival 44 vs.80 days, p<0.0001), compared to miR-142(wt/wt)Tg(P190-BCR/ABL) controls. BM cells (CD45.2) from miR-142(wt/ko)Tg(P190-BCR/ABL) mice (n=4) or miR-142(wt/wt)Tg(P190-BCR/ABL) mice (n=5) were then transplanted into congenic CD45.1 recipient mice (n=18 and n=15 respectively).Recipients of BM cells from miR-142(wt/ko)Tg(P190-BCR/ABL) donors showed increased engraftment (94% vs. 77% in PB at 4 weeks, p<0.0001) and significantly reduced survival(median survival 25 vs. 49 days, p<0.0001), as compared with recipients of BM cells from miR-142(wt/wt)P190-BCR-ABL mice. Finally, upon ex vitro exposure to the TKI nilotinib (5uM for 48 hours), miR-142(wt/ko)Tg(P190-BCR/ABL) BM cells showed reduced apoptosis (7.0% vs.37.5% vs p<0.05) and increased cell viability (66% vs.16.2%, p<0.05) compared with miR-142 (wt/wt)Tg(P190-BCR/ABL) BM cells. In vivo treatment studies with TKI treatment are ongoing and data will be presented at the meeting. In conclusion, miR-142 downregulation promotes rapid Ph+ ALL growth likely by contributing to a blockage of B cell differentiation, and may mediate resistance to TKIs. DisclosuresStein:Celgene: Speakers Bureau; Amgen Inc.: Speakers Bureau. Jin:The National Natural Science Foundation of China: Research Funding; College of Medicine, Zhejiang University: Employment.

KMT2D Is a Haploinsufficient Tumor Suppressor in Acute Leukemia

Introduction: Epigenetic dysregulation plays a critical role in hematologic tumorigenesis and cancer progression. Histone-lysine N-methyltransferase 2D (KMT2D), also known as MLL4 (mixed-lineage leukemia 4), belongs to a family of mammalian histone H3 lysine 4 (H3K4) methyltransferases, which is amongst the most frequently mutated epigenetic genes in human cancers. It was reported that deletion of KMT2D inhibits MLL1-fusion-induced acute myeloid leukemia (Santos et al. 2014). However, in human cancers, the vast majority of the mutations in KMT2D is heterozygous deletion. Recent studies have revealed the role of KMT2D in lymphomagenesis, but the potential tumor suppressor function of KMT2D in leukemogenesis remains largely unclear. In addition, KMT2D was found to exist within a macromolecular complex named COMPASS (complex of proteins associated with Set1). KMT2C is another component of the complex, and was validated as another haploinsufficient tumor suppressor gene in acute myeloid leukemia (Chen et al. 2014). Mutations in KMT2D and KMT2C frequently co-occur in hematologic malignancies. Thus, we sought to first examine the role and molecular mechanism of KMT2D in acute leukemia, and then investigate whether co-mutated gene KMT2D and KMT2C have cooperative function in malignancies initiation and progression.Methods: Here we utilized RNAi approach to knockdown the expression of Kmt2d, and an approximate 50% reduction in gene dosage was validated by quantitative RT-PCR. We introduced two independent short-hairpin RNAs (shRNAs) targeting Kmt2d and a shRNA targeting Nf1 into p53 null hematopoietic stem and progenitor cells (hereafter referred to as shKmt2d;shNf1;p53-/- cells), and transplanted them into sublethally irradiated mice to model the impact of haploinsufficient tumor suppressors. The recipient mice were then monitored for the emergence of diseases by complete blood count as well as overall survival. Bone marrow was harvested and analyzed by flow cytometry after sacrifice. Histological analyses of blood smear, liver, spleen and bone marrow were conducted to accurately diagnose the disease. Besides, we established Kmt2d heterozygous and homozygous conditional knockout mouse models (Kmt2d fl/+; Mx1-Cre, Kmt2d fl/fl; Mx1-Cre) to further investigate the respective role of haploinsufficiency and deletion of KMT2D in acute leukemia. To study the cooperative function of KMT2D and KMT2C in leukemogenesis, two genes were co-suppressed by shRNAs in the same aforementioned genetic background (shNf1; p53-/-). Transplantation-based mouse modeling approach was used and the recipient mice were monitored for evidence of hematologic diseases.Results: A significant increase in peripheral white blood cell counts, anemia and thrombocytopenia were noticed in recipients of shKmt2d;shNf1;p53-/- cells over the same period after 4 weeks post-transplantation. Massive hepatomegaly and splenomegaly were displayed in those mice and a dramatic reduction in survival was observed (shKmt2d-1: median survival = 47 days, p = 0.0004 versus shRen; and shKmt2d-2: median survival = 74 days, p = 0.0127 versus shRen). Flow cytometry of cells from bone marrow of sacrificed mice showed a substantial enrichment of doule-positve cells (shRNAs targeting Kmt2d were linked to GFP and those targeting Nf1 were linked to mCherry) as compared to pre-injected, which were filled with leukemic cells that expressed myeloid/lymphoid lineage markers. Pathological analyses demonstrated the onset of acute myeloid/lymphoid leukemia. In Kmt2d and Kmt2c double-knockdown animal assay, the onset of acute myeloid leukemia was promoted compared with single-knockdown groups. (shKmt2d;shKmt2c: median survival = 48.5 days, p < 0.0001 versus shKmt2d; p = 0.0013 versus shKmt2c).Conclusions: KMT2D is a haploinsufficient tumor suppressor in acute leukemia. KMT2D deficiency cooperates with KMT2C to promote the development and progress of acute leukemia. Further understandings of the molecular mechanism of KMT2D as a haploinsufficient tumor suppressor in acute leukemia and the cooperative function of KMT2D and KMT2C in leukemogenesis are demanded, which can provide insights into developing novel therapeutic targets. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Presentation and Outcome of 199 Patients with 2016 Who Diagnosis of Early and Overt Primary Myelofibrosis Treated with Ruxolitinib

Presentation and Outcome of 199 Patients with 2016 Who Diagnosis of Early and Overt Primary Myelofibrosis Treated with Ruxolitinib

Prognostic importance of Aurora Kinases and mitotic spindle genes transcript levels in Myelodysplastic syndrome

Myelodysplastic syndrome (MDS) are a heterogeneous group of clonal disease characterized by insufficiency of bone marrow, increase of apoptosis and increased risk of acute leukemia progression. Proteins related to the mitotic spindle (AURKA, AURKB, TPX2), to the mitotic checkpoint (MAD2, CDC20) and the regulation of the cell cycle (p21) are directly related to chromosomal stability and tumor development. This study aimed to evaluate the mRNA expression levels of these genes in 101 MDS patients using a real-time PCR methodology. We identified that CDC20 expression are increased in patients with dysmegakaryopoiesis (p=0.024), thrombocytopenia (p=0.000) and high-risk patients (p=0.014, 0.018) MAD2 expression are decreased in patients with 2 or 3 cytopenias (p=0.000) and neutrophil below 800/mm3. TPX2 is also overexpressed in patients presenting dysmegakaryopoiesis (p=0.009). A decrease in AURKA and AURKB expression were observed in patients with altered karyotype (p=0.000), who presented dysplasia in 3 lineages (p=0.000; 0.017) and hemoglobin inferior to 8g/dL (p=0.024). The expression of AURKA, AURKB and MAD2 (p=0.000; 0.001; 0.025) were decreased in patients with hypoplastic MDS, associated with high frequency of chromosomal alterations and high mortality rate. This study reaffirms the importance of aurora kinases and mitotic spindle genes to the pathogenesis and clinical evolution of MDS.

Immunosurveillance during the formation and progression of AML

Despite progress in the treatment of acute leukemia, specific subtypes still have a very bad prognosis, highlighting the need for increased knowledge that can be harnessed to develop novel therapeutic strategies. While experimental data from the last decade have conclusively established that the immune system can critically influence on the development of cancer, with a range of immunomodulatory strategies reaching clinical use, most studies have been conducted using solid cancer models of non-hematological origin. Such cancers evidently have requirements very distinct from hematological cancers that pertain to initiation, maintenance and spreading (metastasis). Also, constraints of experimental models precluding spatiotemporal control have to a large extent hindered investigations of immunosurveillance and immunoediting mechanisms during the multistep progression of acute leukemia. Here, we make use of a recently described mouse model of acute myeloid leukemia AML (Ugale et al, 2014) in which physiologically relevant expression levels of the fusion oncogene MLL-ENL can be conditionally activated in vivo as a leukemic “first-hit”. This model associates with a phase of “pre-leukemic” contraction after which overt clonal transformation commences, highlighting the critical influence of secondary but less defined events during the course of disease. By investigating aspects of the immune system during the formation and progression of AML, we show that transformation follows similar kinetics regardless of developing in wild type (WT) or immune-deficient (Rag2-/- or Rag2-/gc-/-) environments. By contrast, immunity critically influences on the propagation of established leukemia, but with little evidence of primary immune-editing. Rather, intrinsic properties of individual leukemic clones, regardless of their origin, underlie the aggressiveness of arising disease. Antibody-mediated in vivo depletion experiments revealed a critical role for CD8+ cells in this process. Ongoing investigations focus on analyzing and characterizing CD8+ T lymphocyte subsets during the disease course of AML.

MGMT promoter methylation as a potential prognostic marker for acute leukemia.

IntroductionIt has been proved that genetic and epigenetic changes play a significant role in the development and progression of acute leukemia. The aim of our study was to evaluate the frequency and prognostic implications of genetic and epigenetic alterations in p15, MGMT, DNMT3A and TP53 genes in acute leukemias.Material and methodsWe included in the study 59 patients with acute leukemia. Evaluation of TP53 and DNMT3A mutations was performed using sequencing analysis and PCR-RFLP, respectively. Methylation status of MGMT and p15 genes was evaluated using MSP and COBRA, respectively. For assessment of global DNA methylation ELISA-based kit was used.ResultsWe found that overall survival was higher for ALL patients. MGMT promoter methylation was significantly associated with patients age at the time of diagnosis (p = 0.03). TP53 and DNMT3A mutations were observed only in AML patients (16.67% and 8.8%, respectively). Patients with acute leukemia and p15 promoter methylation had significantly more frequently mutated TP53 gene (p = 0.04) and AML patients with p15 promoter methylation had significantly more frequently detected global hypomethylation of DNA (p = 0.009). In the group of ALL patients we noted an opposite trend: only patients negative for p15 promoter methylation were characterized by global DNA hypomethylation.ConclusionsOur findings demonstrate that MGMT promoter methylation can have a considerable impact on the development of acute leukemia in older patients. DNMT3A and TP53 mutations may play a significant role in AML development. However, further studies conducted in a larger cohort of patients are needed to determine its clinical utility.

Inhibition of the Gab2/PI3K/mTOR signaling ameliorates myeloid malignancy caused by Ptpn11 (Shp2) gain-of-function mutations.

Activating mutations, such as E76K and D61Y, in PTPN11 (SHP2), a protein tyrosine phosphatase implicated in multiple cell signaling processes, are associated with 35% of patients with juvenile myelomonocytic leukemia (JMML), an aggressive childhood myeloproliferative neoplasm (MPN). Effective therapeutic interventions for this malignancy are still lacking. Here we show that the interaction between leukemia-associated mutant Shp2 and Gab2, a scaffolding protein important for cytokine-induced PI3K/Akt signaling, was enhanced, and that the mTOR pathway was elevated in Ptpn11E76K/+ leukemic cells. Importantly, MPN induced by the Ptpn11E76K/+ mutation was markedly attenuated in Ptpn11E76K/+/Gab2−/− double mutant mice — Overproduction of myeloid cells was alleviated, splenomegaly was diminished, and myeloid cell infiltration in non-hematopoietic organs was decreased in these double mutants. Excessive myeloid differentiation of stem cells was also normalized by depletion of Gab2. Acute leukemia progression of MPN was reduced in the double mutant mice, and as such, their survival was much prolonged. Furthermore, treatment of Ptpn11E76K/+ mice with Rapamycin, a specific and potent mTOR inhibitor, mitigated MPN phenotypes. Collectively, this study reveals an important role of the Gab2/PI3K/mTOR pathway in mediating the pathogenic signaling of the PTPN11 gain-of-function mutations, and a therapeutic potential of Rapamycin for PTPN11 mutation-associated JMML.

Beclin-1 and hypoxia-inducible factor-1α genes expression: Potential biomarkers in acute leukemia patients.

Beclin-1, an important autophagic gene, and hypoxia-inducible factor-1α (HIF-1α), the master regulator of the hypoxic response, are reported in several human cancers. However, their expressions in acute leukemia haven't yet been well investigated. This study was designed to investigate the gene expression of beclin-1, microtubule-associated protein-1 light chain-3B (MAB1LC3B), the anti-apoptotic marker Bcl-2, and HIF-1α, as well as to evaluate the relationship between their expressions profile and prognosis in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) adult patients. The study involved 30 AML patients, 25 ALL patients, and 20 controls. Gene expression was analyzed using quantitative reverse transcriptase polymerase chain reaction (QRT-PCR). In both AML and ALL groups, beclin-1 and MAB1LC3B expressions were significantly down-regulated (p < 0.001), while HIF-1α (p < 0.01) and Bcl-2 (p < 0.001) expressions were significantly up-regulated compared to the control group. HIF-1α fold expression was significantly negatively correlated with beclin-1 (p < 0.01). Moreover, decreased beclin-1 gene expression and increased HIF-1α gene expression were both associated with poor survival, supporting their pivotal role in the development and progression of acute leukemia. Both Beclin-1 and HIF-1α could be considered as important biomarkers determinants of pathogenesis and survival in acute leukemia.

Low expression of microRNA-204 (miR-204) is associated with poor clinical outcome of acute myeloid leukemia (AML) patients.

BackgroundAcute myeloid leukemia (AML) is a heterogeneous neoplasm of the bone marrow with poor prognosis. In clinical practice new prognostic factors are still needed. MicroRNAs (miRs), small endogenous noncoding RNAs, play an essential role in the development and progression of acute leukemia. The aim of the study was to evaluate miR-204 expression in patients with AML at diagnosis and after induction chemotherapy, in comparison to healthy controls. We also investigated, if miR-204 expression correlates with clinical features of AML patients.MethodsmiR-204 expression has been analyzed using RT-PCR in 95 bone marrow specimens from newly diagnosed AML patients in comparison to 20 healthy subject.ResultsWe showed down-regulated miR-204 expression in AML patients, which was associated with shorter patients’ survival. Higher expression of miR-204 in patients after induction therapy was correlated with complete remission achieving.ConclusionsWe showed low miR-204 expression in AML and found it to be an independent prognostic factor in this patient population.