Gangat, Naseema

Refractory anemia with ring sideroblasts and thrombocytosis (RARS‐T) shares overlapping features of myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). RARS‐T is characterized by SF3B1 and JAK2 mutations and prognosis is considered to be better than MDS but not as good as MPN. The objective of the study was to identify predictors of survival in RARS‐T. We analyzed clinical and laboratory variables in 82 patients and applied a 27‐gene NGS assay to 48 marrow samples obtained at diagnosis. 94% of patients had ≥1 mutations; common mutations being: SF3B1 85%, JAK2 V617F 33%, ASXL1 29%, DNMT3A 13%, SETBP1 13% and TET2 10%. In a multivariable survival analysis ( n = 82), anemia ( P = 0.02) [HB< 10 gm/dl: HR 2.3, 95% CI 1.2–4.6] and abnormal karyotype ( P =.01) [HR 6.1, 95% CI 2.7‐13.8] were independently prognostic for inferior survival. In patients with NGS information ( n = 48), univariate analysis showed association between poor survival and presence of SETBP1 ( P = 0.04) or ASXL1 ( P = 0.08) mutations whereas the absence of these mutations ( ASXL1 wt/ SETBP1 wt) was favorable ( P = 0.04); the number of concurrent mutations did not provide additional prognostication ( P = 0.3). We developed a HR‐weighted prognostic model, with 2 points for an abnormal karyotype, 1 point for either ASXL1 and/or SETBP1 mutations, and 1 point for a HB level < 10 gm/dl, which effectively stratified patients into three risk categories; low (0 points), intermediate (1 point) and high (≥2 points), with median survivals of 80, 42 and 11 months respectively ( P = 0.01). In summary, we confirm the unique mutational landscape in RARS‐T and provide a novel mutation‐enhanced prognostic model. Am. J. Hematol. 91:492–498, 2016. © 2016 Wiley Periodicals, Inc.

The primary objective of treatment in essential thrombocythemia (ET) is to prevent thromboembolic complications. In this regard, advanced age and thrombosis history have long distinguished “low” from “high” risk patients. More recently, JAK2V617F and cardiovascular (CV) risk factors were identified as additional modifiers, leading to the development of a 3‐tiered International Prognostic Score of Thrombosis for ET (IPSET‐thrombosis): “low,” “intermediate,” and “high”. The international data set used to develop IPSET‐thrombosis was recently re‐analyzed in order to quantify the additional pro‐thrombotic effect of JAK2V617F and CV risk factors in specific risk subcategories. The revised IPSET‐thrombosis identified four risk categories based on three adverse variables (thrombosis history, age >60 years and JAK2V617F): very low (no adverse features), low (presence of JAK2V617F), intermediate (age >60 years) and high (presence of thrombosis history or presence of both advanced age and JAK2V617F). In this study of 585 patients with ET (median age 68 years; 61% female), we validated the revised IPSET‐thrombosis by confirming significant differences in thrombosis risk between “very low” and “low” (HR 2.4, 95% CI 1.1 − 5.3) and between “intermediate” and “high” (HR 2.3, 95% CI 1.1 − 5.2) risk patients. Furthermore, in multivariable analysis, only JAK2V617F (HR=1.8, CI= 1.07 − 2.94) and history of thrombosis (HR=2.1, CI= 1.20 − 3.58) were independently predictive of future thrombotic events. The revised IPSET‐thrombosis needs confirmation in prospective studies, especially in terms of risk‐adapted therapy that includes the need for aspirin therapy in very low risk, twice‐daily aspirin therapy for low risk and cytoreductive therapy for low or intermediate risk patients. Am. J. Hematol. 91:390–394, 2016. © 2016 Wiley Periodicals, Inc.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal stem cell disorders with an inherent tendency for leukemic transformation. Diagnosis is currently based on the presence of peripheral blood cytopenias, peripheral blood and bone marrow dysplasia/blasts, and clonal cytogenetic abnormalities. With the advent of next generation sequencing, recurrent somatic mutations in genes involved in epigenetic regulation (TET2, ASXL1, EZH2, DNMT3A, IDH1/2), RNA splicing (SF3B1, SRSF2, U2AF1, ZRSR2), DNA damage response (TP53), transcriptional regulation (RUNX1, BCOR, ETV6) and signal transduction (CBL, NRAS, JAK2) have been identified in MDS. Conventional prognostication is by the revised International prognostic scoring system (IPSS‐R) with additional adverse prognosis conferred by presence of ASXL1, EZH2, or TP53 mutations. Currently Food and Drug administration (FDA)‐approved drugs for the treatment of MDS are not curative and their effect on survival is limited; they include the hypomethylating agents (HMA) azacitidine and decitabine and lenalidomide for MDS with isolated del(5q). To date, allogeneic stem cell transplant (ASCT) remains the only treatment option for possible cure. Given the current lack of drugs with convincing evidence of favorable effect on survival, we consider ASCT as the treatment of choice for most patients with symptomatic disease, and especially for those with high‐risk disease. For nontransplant candidates, participation in clinical trials is preferred over conventional therapy. There is not one right way of treatment for patients who are not candidates for either ASCT or clinical trials and palliative drugs of choice depend on the clinical problem, such as symptomatic anemia (ESAs, danazol, HMA), thrombocytopenia (HMA), or neutropenia (myeloid growth factors). Conversely, there is no controlled evidence to support the use of iron chelating agents in MDS. Going forward, we believe it is time to incorporate mutation information in clinically derived prognostic models in MDS and encourage development of novel drugs with disease‐modifying activity. Am. J. Hematol. 91:76–89, 2016. © 2015 Wiley Periodicals, Inc.

Abstract Nilotinib has been approved to treat newly diagnosed, imatinib-resistant or -intolerant leukemia, but the mechanisms underlying its antileukemia actions remain elusive. Here, we report that nilotinib blocks AML growth through its DNA hypomethylating activity. We showed that, in addition to inducing a reduction of KIT and FLT3 protein expression and phosphorylation, nilotinib downregulated DNMT1, 3a and 3b in Kasumi-1, MV4-11 and C1498 cells. Since DNMT1 is maintenance and de novo DNMT, we focused on DNMT1 and proved that nilotinib impaired DNMT1 expression via Sp1 dysfunction, since the luciferase activity driven by DNMT1 promoter containing Sp1 binding sites was decreased by 2.6 fold by nilotinib, while increased by 10.6 fold after Sp1 overexpression. Electrophoretic mobility shift assay disclosed that nilotinib abolished Sp1 binding on DNMT1 promoter. Dotblot using 5mC antibody revealed global DNA hypomethylation and qPCR showed p15INK4B upregulation in Kasumi-1 (3.4 fold) or MV4-11 (5.2 fold). Bisulfite sequencing found a decrease of DNA methylation on p15INK4B promoter from 100% to 89% in Kasumi-1 or 13% to 0% in MV4-11. The functional assays showed a decrease of colony formation in Kasumi-1 (60%) or MV4-11 (58%), and an increase of cell apoptosis in Kasumi-1 (6.9 fold) or MV4-11 (3.2 fold). We verified these findings in AML patient blasts (n = 3) by showing that nilotinib treatment led to the dephosphorylation of KIT, the downregulation of DNMT1, 3a, 3b and Sp1, the reduction of global DNA methylation and the re-expression of p15INK4B (4.4 fold) via promoter demethylation (from 14% to 6%), which was followed by suppressed colony formation (77%), promoted cell apoptosis (1.84 fold) and increased caspase-3 and caspase-8. To test if nilotinib induces AML regression via DNA hypomethylation in vivo, 0.1×106 C1498 cells were injected into C57BL/6 mice (n = 3 mice/group) via the tail vein. The leukemic mice were treated with 5, 10 or 15 mg/kg of nilotinib in PEG400 plus saline via intraperitoneal injection twice a week for a total of 6 doses. No toxicity was observed for the tested drug dosage and schedule, because of no evident change of mouse body weight. Compared to the control group, nilotinib-treated mice had a decrease in spleen size. H&E staining showed that the control mice exhibited increased infiltration of AML cells into the spleen, lung and liver of recipients. The bone marrow (BM) histopathology identified a higher degree of mature post-mitotic cells containing metamyelocytes, bands and segmented neutrophils in nilotinib-treated mice than control. DNMT1 was downregulated (39%), p15INK4B was upregulated and global DNA methylation was reduced (60%) in BM cells from nilotinib-treated mice. Thus, our findings unveil DNA methylation machinery as an innovative target behind nilotinib's anticancer activities, and provide a new therapeutic avenue for nilotinib in overcoming aberrant epigenetics in AML. Note: This abstract was not presented at the meeting. Citation Format: Na Shen, Fei Yan, Jiuxia Pang, Naseema Gangat, Mark R. Litzow, Aref Al-Kali, Shujun Liu. Nilotinib abrogates DNMT1-depenent DNA methylation: A novel mechanism for induction of AML leukemia regression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2945. doi:10.1158/1538-7445.AM2015-2945

SummaryAmong 826 patients with primary myelofibrosis (PMF) and analysable metaphases on cytogenetic studies, 352 (42·6%) had abnormal karyotype, of which 240 (68·2%) were sole aberrations and 48 (13·6%) were complex; the most frequent abnormalities were 20q− (23·3%), 13q− (18·2%), +8 (11·1%), +9 (9·9%), chromosome 1q+ (9·7%) and −7/7q− (7·1%). Phenotypic correlates included: abnormal karyotype with anaemia (P = 0·02), leucopenia (P < 0·01) and thrombocytopenia (P < 0·01); complex karyotype with younger age (P = 0·04) and thrombocytopenia (P < 0·01); leucopenia with 20q−, +8 and −7/7q− and thrombocytopenia with 20q− and −7/7q−. Cytopenias were less likely to occur with 13q−. 476 patients were annotated for JAK2/CALR/MPL mutations; abnormal karyotype frequencies were 43% in JAK2, 42% CALR, 33% MPL mutated and 34% triple‐negative cases (P = 0·3). A proportion of patients were also screened for ASXL1, EZH2, IDH1, IDH2, SRSF2, U2AF1 and SF3B1 mutations; in all instances, mutational frequencies were higher in patients with normal karyotype, reaching significance for ASXL1 (P = 0·02) and U2AF1 (P = 0·01). 13q− was associated with mutant CALR (P = 0·03), +9 with mutant JAK2 (P = 0·02) and 20q− with mutant SRSF2 (P = 0·02). The current PMF study provides detailed cytogenetic information and correlations with mutations and clinical phenotype.

Key Points Survival in ET is superior to that of PV, regardless of mutational status, but remains inferior to the sex- and age-matched US population. JAK2/CALR/MPL mutational status is prognostically informative in PMF, regarding overall and leukemia-free survival.

AbstractBackgroundVascular events in essential thrombocythemia (ET) are associated with advanced age and thrombosis history. Recent information suggests additional effect from the presence of specific mutations.ObjectivesTo examine the influence of age and thrombosis history on the reported association between mutational status and thrombosis‐free survival in ET.Patients and MethodsAnalysis was performed using a Mayo Clinic cohort of 300 ET patients, and key findings were reanalyzed by including additional 102 Italian patients.ResultsAmong 300 Mayo patients with ET (median age 55 yr, 60% females), mutational frequencies were 53% JAK2, 32% CALR, 3% MPL, and 12% JAK2, CALR and MPL wild type. One hundred and six (35%) patients experienced arterial (n = 75) or venous (n = 43) events, before (n = 55) or after (n = 71) diagnosis. In univariate analysis, compared to JAK2‐mutated cases, JAK2, CALR and MPL wild type (HR 0.31, 95% CI 0.11–0.86), and CALR‐mutated (0.53, 95% CI 0.30–0.92) patients displayed better thrombosis‐free survival. JAK2, CALR, and MPL wild type remained significant (P = 0.03; HR 0.32, 95% CI 0.11–0.9) during multivariable analysis that included age (P = 0.01) and thrombosis history (P = 0.0006); a favorable impact from CALR mutations was of borderline significance (P = 0.1; HR 0.62, 95% CI 0.35–1.1), but became significant (P = 0.02) when multivariable analysis including thrombosis history (P = 0.02) was performed on patients younger than 60 yr of age.ConclusionsThe favorable impact of mutational status on thrombosis‐free survival in ET might be most evident for JAK2, CALR, and MPL wild type patients, whereas the favorable effect from CALR mutations might be confined to young patients.