Phospholipid metabolic adaptation promotes survival of IDH2 mutant acute myeloid leukemia cells.

Genetic mutations in the isocitrate dehydrogenase (IDH) gene that result in a pathological enzymatic activity to produce oncometabolite have been detected in acute myeloid leukemia (AML) patients. While specific inhibitors that target mutant IDH enzymes and normalize intracellular oncometabolite level have been developed, refractoriness and resistance has been reported. Since acquisition of pathological enzymatic activity is accompanied by the abrogation of the crucial WT IDH enzymatic activity in IDH mutant cells, aberrant metabolism in IDH mutant cells can potentially persist even after the normalization of intracellular oncometabolite level. Comparisons of isogenic AML cell lines with and without IDH2 gene mutations revealed two mutually exclusive signalings for growth advantage of IDH2 mutant cells, STAT phosphorylation associated with intracellular oncometabolite level and phospholipid metabolic adaptation. The latter came to light after the oncometabolite normalization and increased the resistance of IDH2 mutant cells to arachidonic acid-mediated apoptosis. The release of this metabolic adaptation by FDA-approved anti-inflammatory drugs targeting the metabolism of arachidonic acid could sensitize IDH2 mutant cells to apoptosis, resulting in their eradication in vitro and in vivo. Our findings will contribute to the development of alternative therapeutic options for IDH2 mutant AML patients who do not tolerate currently available therapies.

A case of primary nonleukemic myeloid sarcoma of the spleen, successfully treated by surgery and hematopoietic stem cell transplantation.

BACKGROUND: Myeloid sarcoma (MS) is a rare disease, mostly found in conjunction with acute myelogenous leukemia or other diseases, and primary nonleukemic MS of the spleen is particularly rare. CASE PRESENTATION: We report a 57-year-old male who presented with a spleen mass that was found incidentally, and was enlarged. As a result of various examinations, he was diagnosed with primary MS of the spleen with suspected involvement of the transverse colon, left kidney, pancreatic tail, and left diaphragm. He underwent a total splenectomy, partial pancreatectomy, partial colectomy, left nephrectomy, and left diaphragm partial resection. Histological examination revealed splenic primary MS. Bone marrow biopsy and immunophenotypic flow cytometry revealed no evidence of myeloid leukemia. He underwent umbilical cord blood transplantation, and he is currently living without a sign of recurrence at 10 months after surgery. CONCLUSIONS: We experienced a very rare case of primary spleen MS that was discovered without a hematologic malignancy. Two cases of surgically resected primary splenic MS have been reported, including the present case.

A regulatory element in the 3'-untranslated region of CEBPA is associated with myeloid/NK/T-cell leukemia.

OBJECTIVES: CCAAT/enhancer-binding protein α (CEBPA) is an essential transcription factor for myeloid differentiation. Not only mutation of the CEBPA gene, but also promoter methylation, which results in silencing of CEBPA, contributes to the pathogenesis of acute myeloid leukemia (AML). We sought for another differentially methylated region (DMR) that associates with the CEBPA silencing and disease phenotype. METHODS: Using databases, we identified a conserved DMR in the CEBPA 3'-untranslated region (UTR). RESULTS: Methylation-specific PCR analysis of 231 AML cases showed that hypermethylation of the 3'-UTR was associated with AML that had a myeloid/NK/T-cell phenotype and downregulated CEBPA. Most of these cases were of an immature phenotype with CD7/CD56 positivity. These cases were significantly associated with lower hemoglobin levels than the others. Furthermore, we discovered that the CEBPA 3'-UTR DMR can enhance transcription from the CEBPA native promoter. In vitro experiments identified IKZF1-binding sites in the 3'-UTR that are responsible for this increased transcription of CEBPA. CONCLUSIONS: These results indicate that the CEBPA 3'-UTR DMR is a novel regulatory element of CEBPA related to myeloid/NK/T-cell lineage leukemogenesis. Transcriptional regulation of CEBPA by IKZF1 may provide a clue for understanding the fate determination of myeloid vs. NK/T-lymphoid progenitors.

Hematopoietic stem cells acquire survival advantage by loss of RUNX1 methylation identified in familial leukemia.

RUNX1 is among the most frequently mutated genes in human leukemia, and the loss or dominant-negative suppression of RUNX1 function is found in myelodysplastic syndrome and acute myeloid leukemia (AML). How posttranslational modifications (PTMs) of RUNX1 affect its in vivo function, however, and whether PTM dysregulation of RUNX1 can cause leukemia are largely unknown. We performed targeted deep sequencing on a family with 3 occurrences of AML and identified a novel RUNX1 mutation, R237K. The mutated R237 residue is a methylation site by protein arginine methyltransferase 1, and loss of methylation reportedly impairs the transcriptional activity of RUNX1 in vitro. To explore the biologic significance of RUNX1 methylation in vivo, we used RUNX1 R233K/R237K double-mutant mice, in which 2 arginine-to-lysine mutations precluded RUNX1 methylation. Genetic ablation of RUNX1 methylation led to loss of quiescence and expansion of hematopoietic stem cells (HSCs), and it changed the genomic and epigenomic signatures of phenotypic HSCs to a poised progenitor state. Furthermore, loss of RUNX1 R233/R237 methylation suppressed endoplasmic reticulum stress-induced unfolded protein response genes, including Atf4, Ddit3, and Gadd34; the radiation-induced p53 downstream genes Bbc3, Pmaip1, and Cdkn1a; and subsequent apoptosis in HSCs. Mechanistically, activating transcription factor 4 was identified as a direct transcriptional target of RUNX1. Collectively, defects in RUNX1 methylation in HSCs confer resistance to apoptosis and survival advantage under stress conditions, a hallmark of a preleukemic clone that may predispose affected individuals to leukemia. Our study will lead to a better understanding of how dysregulation of PTMs can contribute to leukemogenesis.

Author Correction: Lineage-specific RUNX2 super-enhancer activates MYC and promotes the development of blastic plasmacytoid dendritic cell neoplasm.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Lineage-specific RUNX2 super-enhancer activates MYC and promotes the development of blastic plasmacytoid dendritic cell neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive subtype of acute leukemia, the cell of origin of which is considered to be precursors of plasmacytoid dendritic cells (pDCs). Since translocation (6;8)(p21;q24) is a recurrent anomaly for BPDCN, we demonstrate that a pDC-specific super-enhancer of RUNX2 is associated with the MYC promoter due to t(6;8). RUNX2 ensures the expression of pDC-signature genes in leukemic cells, but also confers survival and proliferative properties in BPDCN cells. Furthermore, the pDC-specific RUNX2 super-enhancer is hijacked to activate MYC in addition to RUNX2 expression, thereby promoting the proliferation of BPDCN. We also demonstrate that the transduction of MYC and RUNX2 is sufficient to initiate the transformation of BPDCN in mice lacking Tet2 and Tp53, providing a model that accurately recapitulates the aggressive human disease and gives an insight into the molecular mechanisms underlying the pathogenesis of BPDCN.

Pancytopenia and Myelodysplastic Changes in Aceruloplasminemia: A Case with a Novel Pathogenic Variant in the Ceruloplasmin Gene.

A 72-year-old Japanese woman suffered from mild pancytopenia 3 years before her initial hospitalization. On admission, the levels of trace elements, particularly copper, and ceruloplasmin were significantly decreased in her blood serum. Abdominal lymphadenopathy and bone marrow dysplasia were detected. Hemosiderin deposition was observed in her lymph nodes and bone marrow, and magnetic resonance imaging suggested its deposition in various organs. A novel missense pathogenic variant (c.T1670G) was detected in the ceruloplasmin gene, resulting in an amino acid change (p.M557R). When copper deficiency is accompanied by cytopenia and dysplasia in a patient, it is worthwhile to consider a differential diagnosis of aceruloplasminemia.

Isolated Pancreatic Myeloid Sarcoma Associated with t(8;21)/RUNX1-RUNX1T1 Rearrangement.

No valid treatment for isolated myeloid sarcoma (IMS) has yet been established, and no thorough genetic examinations have been performed because of its low incidence and unique manner of development. We herein report a 34-year-old man with pancreatic IMS with t(8;21)/RUNX1-RUNX1T1 rearrangement. He was treated with high-dose cytarabine followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). This is the first report of pancreatic IMS with t(8;21). Positron emission tomography/computed tomography and genetic study are useful for the diagnosis, and allo-HSCT achieved complete remission in this patient.

Lineage switch with t(6;11)(q27;q23) from T-cell lymphoblastic lymphoma to acute monoblastic leukemia at relapse.

We present a patient with T-cell lymphoblastic lymphoma (T-LBL) harboring t(6;11)(q27;q23) that converted to acute monoblastic leukemia at relapse. A 27-year-old man developed T-LBL with a mediastinal mass. He exhibited several recurrences in the central nervous system and marrow. A fifth relapse occurred in the marrow, with 42.8% blasts with CD4, CD5, CD7, CD10, CD33, CD34, HLA-DR and cytoplasmic (cy) CD3. While achieving complete remission with nelarabine, sixth relapse occurred in the marrow with 6.8% blasts, which had characteristics of monoblastic features, 2 months later. Marrow blasts were positive for myeloperoxidase, CD4, CD33, CD56, CD64, and HLA-DR, but were negative for cyCD3, CD5, CD7, CD10, and CD34. Marrow cells at both the 5th lymphoid and 6th myeloid relapses had t(6;11)(q27;q23) and the same MLL-MLLT4 fusion transcript. In addition, the MLL-MLLT4 fusion sequences documented in the initial mediastinal cells were the same as seen in peripheral blood cells at the 6th relapse. The patient continues 7th remission after one course of gemtuzumab ozogamicin therapy followed by cord blood transplantation for more than 3 years. Sequential phenotypic and cytogenetic studies may yield valuable insights into the mechanism of leukemic recurrence and possible implications for treatment selection.

IDH1 and IDH2 mutations confer an adverse effect in patients with acute myeloid leukemia lacking the NPM1 mutation.

We examined the incidence and prognostic effect of IDH1 and IDH2 mutations in 233 Japanese adults with acute myeloid leukemia (AML). IDH1 R132 mutations were detected in 20 (8.6%) patients with AML. IDH2 mutations were found in 19 (8.2%, 17 R140 and two R172) patients. IDH1 and IDH2 mutations were mutually exclusive and were associated with normal karyotype AML, cytogenetic intermediate-risk group, and NPM1 mutations. Five-year overall survival (OS) rates were significantly lower (15.6%) in patients harboring the IDH mutations than in patients lacking the IDH mutation (32.0%) in the entire cohort of AML (P = 0.005). Among patients aged 59 yr or younger with IDH mutations, 5-yr OS in patients who underwent allogeneic stem cell transplantation (SCT) was significantly higher than that in those not receiving allogeneic SCT (50% vs. 10.6%, P = 0.020). Of 51 patients with NPM1 mutations, there was no significant difference in 5-yr OS rates between patients with and those without the IDH mutations. In contrast, among 175 patients lacking the NPM1 mutations, 5-yr OS rate in patients with IDH mutations was significantly lower than that in those without IDH mutations (0% vs. 34.7%, P = <0.001). These data suggest that IDH mutations have an unfavorable effect in AML, especially AML with the NPM1 wild type and younger AML patients with IDH mutations may benefit from allogeneic SCT.

High frequency of IKZF1 genetic alterations in adult patients with B-cell acute lymphoblastic leukemia.

Alterations in the IKZF1 gene are associated with poor prognosis in pediatric B-cell acute lymphoblastic leukemia (B-ALL). We examined the relationship between IKZF1 alterations and clinical findings in 78 adult patients with B-ALL. Aberrant isoforms of IKZF1 were detected using RT-PCR. The copy numbers of IKZF1 exons and fusion genes caused by exon deletions were determined using RQ-PCR and genomic PCR, respectively. We detected aberrant IKZF1 isoforms in 20 of the 78 patients (13 Ik6 and seven Ik10) and deletions of the entire or parts of the IKZF1 gene in 40 of 70 patients. No IKZF1 point mutations were detected by direct sequencing. Nineteen Ik6 and Ik10 isoforms had been generated through genomic exon deletions, but one through aberrant splicing. In total, 41 of the 78 (52.6%) patients harbored IKZF1 alterations, which were identified in 20 of 24 (83.3%) patients with Philadelphia chromosome (Ph)-positive B-ALL compared with 21 of 54 (38.9%) Ph-negative B-ALL (P = 0.0004). IKZF1 alterations are highly involved even in adults with B-ALL. To fully detect IKZF1 alterations, several methods with alternative approaches are required. To elucidate the clinical significance of IKZF1 alterations in adult B-ALL, our study warrants prospective clinical studies with a full analysis of IKZF1 alterations.

Protective Effect of Brazilian Propolis against Liver Damage with Cholestasis in Rats Treated with α-Naphthylisothiocyanate.

We examined the protective effect of Brazilian propolis against liver damage with cholestasis in rats treated with α-naphthylisothiocyanate (ANIT) in comparison with that of vitamin E (VE). Rats orally received Brazilian propolis ethanol extract (BPEE) (25, 50, or 100 mg/kg), VE (250 mg/kg) or vehicle at 12 h after intraperitoneal injection of ANIT (75 mg/kg) and were killed 24 h after the injection. Vehicle-treated rats showed liver cell damage and cholestasis, judging from the levels of serum marker enzymes and components. The vehicle group had increased serum total cholesterol, triglyceride, phospholipid, and lipid peroxide levels, increased hepatic lipid peroxide, reduced glutathione, and ascorbic acid levels and myeloperoxidase activity, and decreased hepatic superoxide dismutase activity. BPEE (50 mg/kg) administered to ANIT-treated rats prevented liver cell damage and cholestasis and attenuated these serum and hepatic biochemical changes except hepatic ascorbic acid, although administered BPEE (25 or 100 mg/kg) was less effective. VE administered to ANIT-treated rats prevented liver cell damage, but not cholestasis, and attenuated increased serum lipid peroxide level, increased hepatic lipid peroxide level and myeloperoxidase activity, and decreased hepatic superoxide dismutase activity. These results indicate that BPEE protects against ANIT-induced liver damage with cholestasis in rats more effectively than VE.

Protective effect of Brazilian propolis against hepatic oxidative damage in rats with water-immersion restraint stress.

In the present study we examined the protective effect of Brazilian propolis against hepatic oxidative damage in rats with water-immersion restraint stress (WIRS) in comparison with that of vitamin E (VE). Fasted rats orally received Brazilian green propolis ethanol extract (BPEE; 10, 50 or 100 mg/kg), VE (250 mg/kg) or vehicle at 30 min before the onset of WIRS. Exposure of vehicle-treated rats to 6 h of WIRS caused liver cell damage, judging from the levels of serum alanine aminotransferase and aspartate aminotransferease, increased hepatic lipid peroxide, NO(x) contents and myeloperoxidase activity, and decreased hepatic non-protein SH, ascorbic acid contents and superoxide dismutase activity. Preadministration of BPEE (50 or 100 mg/kg) or VE to the stressed rats protected against the hepatic damage and attenuated the increased hepatic lipid peroxide and NO(x) contents and myeloperoxidase activity and the decreased hepatic non-protein SH and ascorbic acid contents and superoxide dismutase activity. These protective effects of BPEE (50 mg/kg) were greater than those of BPEE (100 mg/kg) and were almost equal to those of VE. These results indicate that BPEE protects against hepatic oxidative damage in rats exposed to WIRS possibly through its antioxidant and antiinflammatory properties such as VE.

Effect of prior Salter or Chiari osteotomy on THA with developmental hip dysplasia.

BACKGROUND: Controversy exists regarding the outcome of THA after prior pelvic osteotomy. QUESTIONS/PURPOSES: We conducted a retrospective chart and radiographic review to obtain outcome measures for perioperative complications, acetabular and femoral component revisions, Harris hip score, and survivorship and compared these outcomes for patients presenting with developmental dysplasia of the hip treated surgically using THA with and without prior pelvic osteotomy. PATIENTS AND METHODS: We performed 103 primary THAs in 87 patients with osteoarthritis secondary to developmental dysplasia of the hip with a minimum 3-year followup. Previous pelvic osteotomy was performed in 52 hips (Salter, 40; Chiari, nine; Salter and Chiari, three), and 51 hips had no previous surgery (control group). RESULTS: The pelvic osteotomy group did not have higher rates of femoral or acetabular intraoperative fracture or dislocation compared with the control group. The overall revision rate was 28.8% in the pelvic osteotomy group compared with 19.6% in the control group. The revision rate for aseptic loosening was 23.1% in the pelvic osteotomy group compared with 17.6% in the control group. Harris hip scores (range, 20-87) were not compromised, and overall survivorship rates 8 years postoperatively were not different at any time between the pelvic osteotomy (83.3%) and control (88.4%) groups. CONCLUSIONS: Prior pelvic osteotomy did not lead to a higher perioperative complication rate, higher revision rate, compromised Harris hip score, or shortened survivorship in eventual THA in developmental dysplasia of the hip. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Octacosanol attenuates disrupted hepatic reactive oxygen species metabolism associated with acute liver injury progression in rats intoxicated with carbon tetrachloride.

We examined whether octacosanol, the main component of policosanol, attenuates disrupted hepatic reactive oxygen species metabolism associated with acute liver injury progression in rats intoxicated with carbon tetrachloride (CCl(4)). In rats intoxicated with CCl(4) (1 ml/kg, i.p.), the activities of serum transaminases increased 6 h after intoxication and further increased at 24 h. In the liver of CCl(4)-intoxicated rats, increases in lipid peroxide (LPO) concentration and myeloperoxidase activity and decreases in superoxixde dismutase activity and reduced glutathione (GSH) concentration occurred 6 h after intoxication and these changes were enhanced with an increase in xanthine oxidase activity and a decrease in catalase activity at 24 h. Octacosanol (10, 50 or 100 mg/kg) administered orally to CCl(4)-intoxicated rats at 6 h after intoxication attenuated the increased activities of serum transaminases and the increased hepatic myeloperoxidase and xanthine oxidase activities and LPO concentration and the decreased hepatic superoxide dismutase and catalase activities and GSH concentration found at 24 h after intoxication dose-dependently. Octacosanol (50 or 100 mg/kg) administered to untreated rats decreased the hepatic LPO concentration and increased the hepatic GSH concentration. These results indicate that octacosanol attenuates disrupted hepatic reactive oxygen species metabolism associated with acute liver injury progression in CCl(4)-intoxicated rats.

Xanthine oxidase-derived reactive oxygen species contribute to the development of D-galactosamine-induced liver injury in rats.

We examined whether xanthine oxidase (XO)-derived reactive oxygen species (ROS) contribute to the development of D-galactosamine (D-GaIN)-induced liver injury in rats. In rats treated with D-GaIN (500 mg/kg), liver injury appeared 6 h after treatment and developed until 24 h. Hepatic XO and myeloperoxidase activities increased 12 and 6 h, respectively, after D-GalN treatment and continued to increase until 24 h. D-GalN-treated rats had increased hepatic lipid peroxide (LPO) content and decreased hepatic reduced glutathione (GSH) and ascorbic acid contents and superoxide dismutase (SOD), catalase and Se-glutathione peroxidase (Se-GSHpx) activities at 24 h, but not 6 h, after treatment. Allopurinol (10, 25 or 50 mg/kg) administered at 6 h after D-GalN treatment attenuated not only the advanced liver injury and increased hepatic XO activity but also all other changes observed at 24 h after the treatment dose-dependently. These results suggest that XO-derived ROS contribute to the development of D-GaIN-induced liver injury in rats.

Bone remodeling is different in metaphyseal and diaphyseal-fit uncemented hip stems.

Femoral component stability in uncemented total hip arthroplasties depends on periprosthetic bone remodeling. Stem design is an important factor influencing bone remodeling, however the design that promotes the most bone remodeling is unclear. We examined metaphyseal and diaphyseal-fit stems to determine the effect of stem design on bone remodeling and stability. Twenty-three patients who had total hip arthroplasties (28 hips) with metaphyseal-fit stems were matched with 27 patients (32 hips) who had uncemented total hip arthroplasties with diaphyseal-fit stems. We assessed preoperative radiographs for canal fill, canal shape, and bone quality. We then assessed postoperative radiographs for periprosthetic bone remodeling including spot welds, cortical hypertrophy, and pedestal formation. Patients were examined clinically using a modified Harris hip score. Patients with metaphyseal stems had increased cortical hypertrophy 1 year postoperatively. However, there was no functional difference 2 years postoperatively. Both stem designs resulted in bone remodeling by 2 years postoperatively with similar clinical results.

Successively postadministered melatonin prevents disruption of hepatic antioxidant status in rats with bile duct ligation.

We have reported that orally administered melatonin exerts a therapeutic effect on cholestatic liver injury in rats treated with bile duct ligation (BDL) possibly through its antioxidant and anti-inflammatory actions. Herein, we examined whether successively postadministered melatonin prevents the disruption of hepatic antioxidant status in BDL-treated rats. Wistar rats with BDL were killed 5 and 13 days after BDL. Melatonin (10 or 100 mg/kg body weight) was orally administered to rats with and without BDL everyday for 8 days, starting 5 days after BDL. The hepatic concentrations of thiobarbituric acid reactive substances, an index of lipid peroxidation, and reduced glutathione increased 5 days after BDL and further increased at 13 days. Hepatic vitamin E concentration and catalase and Se-glutathione peroxidase (Se-GSH-Px) activities were similarly reduced at 5 and 13 days after BDL. Hepatic ascorbic acid concentration and the hepatic activities of Cu,Zn- and Mn-superoxide dismutases, glutathione reductase, and glucose-6-phosphate dehydrogenase decreased 13 days after BDL. Melatonin postadministered to BDL-treated rats attenuated all these changes observed at 13 days after the treatment more effectively at the higher dose than at the lower dose. Melatonin administered to BDL-untreated rats increased the hepatic Se-GSH-Px activity at both doses and the hepatic activities of Cu,Zn- and Mn-superoxide dismutases at the higher dose. These results indicate that successively postadministered melatonin at pharmacological doses prevents the disruption of hepatic antioxidant status in rats with BDL through its direct and indirect antioxidant action, which may contribute to its therapeutic effect of BDL-induced cholestatic liver injury.