Metabolic dependencies and vulnerabilities in leukemia.

Leukemia cell proliferation requires up-regulation and rewiring of metabolic pathways to feed anabolic cell growth. Oncogenic drivers directly and indirectly regulate metabolic pathways, and aberrant metabolism is central not only for leukemia proliferation and survival, but also mediates oncogene addiction with significant implications for the development of targeted therapies. This review explores leukemia metabolic circuitries feeding anabolism, redox potential, and energy required for tumor propagation with an emphasis on emerging therapeutic opportunities.

The role of SF3B1 and NOTCH1 in the pathogenesis of leukemia.

The discovery of new genes/pathways improves our knowledge of cancer pathogenesis and presents novel potential therapeutic options. For instance, splicing factor 3b subunit 1 (SF3B1) and NOTCH1 genetic alterations have been identified at a high frequency in hematological malignancies, such as leukemia, and may be related to the prognosis of involved patients because they change the nature of malignancies in different ways like mediating therapeutic resistance; therefore, studying these gene/pathways is essential. This review aims to discuss SF3B1 and NOTCH1 roles in the pathogenesis of various types of leukemia and the therapeutic potential of targeting these genes or their mutations to provide a foundation for leukemia treatment.

Identification of MYC as an antinecroptotic protein that stifles RIPK1-RIPK3 complex formation.

The underlying mechanism of necroptosis in relation to cancer is still unclear. Here, MYC, a potent oncogene, is an antinecroptotic factor that directly suppresses the formation of the RIPK1-RIPK3 complex. Gene set enrichment analyses reveal that the MYC pathway is the most prominently down-regulated signaling pathway during necroptosis. Depletion or deletion of MYC promotes the RIPK1-RIPK3 interaction, thereby stabilizing the RIPK1 and RIPK3 proteins and facilitating necroptosis. Interestingly, MYC binds to RIPK3 in the cytoplasm and inhibits the interaction between RIPK1 and RIPK3 in vitro. Furthermore, MYC-nick, a truncated form that is mainly localized in the cytoplasm, prevented TNF-induced necroptosis. Finally, down-regulation of MYC enhances necroptosis in leukemia cells and suppresses tumor growth in a xenograft model upon treatment with birinapant and emricasan. MYC-mediated suppression of necroptosis is a mechanism of necroptosis resistance in cancer, and approaches targeting MYC to induce necroptosis represent an attractive therapeutic strategy for cancer.

A genome-scale in vivo loss-of-function screen identifies Phf6 as a lineage-specific regulator of leukemia cell growth.

We performed a genome-scale shRNA screen for modulators of B-cell leukemia progression in vivo. Results from this work revealed dramatic distinctions between the relative effects of shRNAs on the growth of tumor cells in culture versus in their native microenvironment. Specifically, we identified many "context-specific" regulators of leukemia development. These included the gene encoding the zinc finger protein Phf6. While inactivating mutations in PHF6 are commonly observed in human myeloid and T-cell malignancies, we found that Phf6 suppression in B-cell malignancies impairs tumor progression. Thus, Phf6 is a "lineage-specific" cancer gene that plays opposing roles in developmentally distinct hematopoietic malignancies.

Impact of respiratory physical therapy on heart rate autonomic control in children with leukemia.

INTRODUCTION: Considering that heart rate (HR) autonomic control is impaired in cancer and subsequent respiratory effort may overload the heart, we aimed to evaluate the effect of a respiratory physical therapy session on HR autonomic regulation in children with leukemia so as to confirm its safety. METHODS: We selected children with leukemia (n = 10) and healthy children (n = 11), which were submitted to a session of respiratory physical therapy. We used Spiron Kids (NCS, Brazil), Children's Voldyne (HUDSON RCI, USA), and Shaker (NCS, Brazil) as respiratory devices. The respiratory exercise protocols were founded on three standardized protocols. HR variability (HRV) was analyzed before, in the first minute and 5 to 10 min after intervention. RESULTS: We recognized no change between rest and recovery from intervention in HRV (rMSSD-square root mean square of the differences between adjacent normal R-R intervals)-Control: p = 0.8111, Leukemia: p = 0.1197, among groups: p = 0.6574; SD1-standard deviation from instantaneous beat-to-beat variability-Control: p = 0.8111, Leukemia: p = 0.131, among groups: p = 0.6556; 0V-with no variation (3 equal symbols, for example (2,2,2)-Control: p = 0.3679, Leukemia: p = 0.3553, among groups: p = 0.7421); 2UV-with two variations to the contrary (the three symbols form a peak or a valley, for instance (3,5,3)-Control: p = 0.3679, Leukemia: p = 0.2359, among groups: p = 0.4007). HF-high frequency component, range 0.15 to 0.4 Hz-decreased 0 to 1 min after intervention in the leukemia group (p = 0.0303) and no change was observed in the control group between rest versus recovery from intervention (p = 0.9761). No significant change was reported in HF between groups (p = 0.8700). Two leukemia subjects treated with vincristine presented different HRV responses to the intervention group. CONCLUSION: A respiratory physical therapy session did not significantly change autonomic control of HR in children with leukemia. Yet, clinicians should be mindful of subjects undergoing treatment with vincristine.

New Succinimides with Potent Anticancer Activity: Synthesis, Activation of Stress Signaling Pathways and Characterization of Apoptosis in Leukemia and Cervical Cancer Cells.

Based on previously identified dicarboximides with significant anticancer and immunomodulatory activities, a series of 26 new derivatives were designed and synthesized by the Diels-Alder reaction between appropriate diene and maleimide or hydroxymaleimide moieties. The resulting imides were functionalized with alkanolamine or alkylamine side chains and subsequently converted to their hydrochlorides. The structures of the obtained compounds were confirmed by 1H and 13C NMR and by ESI MS spectral analysis. Their cytotoxicity was evaluated in human leukemia (K562, MOLT4), cervical cancer (HeLa), and normal endothelial cells (HUVEC). The majority of derivatives exhibited high to moderate cytotoxicity and induced apoptosis in K562 cells. Microarray gene profiling demonstrated upregulation of proapoptotic genes involved in receptor-mediated and mitochondrial cell death pathways as well as antiapoptotic genes involved in NF-kB signaling. Selected dicarboximides activated JNK and p38 kinases in leukemia cells, suggesting that MAPKs may be involved in the regulation of apoptosis. The tested dicarboximides bind to DNA as assessed by a plasmid DNA cleavage protection assay. The selected dicarboximides offer new scaffolds for further development as anticancer drugs.

PTEN action in leukaemia dictated by the tissue microenvironment.

PTEN encodes a lipid phosphatase that is underexpressed in many cancers owing to deletions, mutations or gene silencing. PTEN dephosphorylates phosphatidylinositol (3,4,5)-triphosphate, thereby opposing the activity of class I phosphatidylinositol 3-kinases that mediate growth- and survival-factor signalling through phosphatidylinositol 3-kinase effectors such as AKT and mTOR. To determine whether continued PTEN inactivation is required to maintain malignancy, here we generate an RNA interference-based transgenic mouse model that allows tetracycline-dependent regulation of PTEN in a time- and tissue-specific manner. Postnatal Pten knockdown in the haematopoietic compartment produced highly disseminated T-cell acute lymphoblastic leukaemia. Notably, reactivation of PTEN mainly reduced T-cell leukaemia dissemination but had little effect on tumour load in haematopoietic organs. Leukaemia infiltration into the intestine was dependent on CCR9 G-protein-coupled receptor signalling, which was amplified by PTEN loss. Our results suggest that in the absence of PTEN, G-protein-coupled receptors may have an unanticipated role in driving tumour growth and invasion in an unsupportive environment. They further reveal that the role of PTEN loss in tumour maintenance is not invariant and can be influenced by the tissue microenvironment, thereby producing a form of intratumoral heterogeneity that is independent of cancer genotype.

Is heart rate variability a valuable method to investigate cardiac autonomic dysfunction in subjects with leukemia? A systematic review to evaluate its importance in clinical practice.

Impaired cardiovascular and autonomic function during treatment and during recovery from leukemia has been indicated. In this context, heart rate variability (HRV) is a non-invasive measure that describes the oscillations of the intervals between consecutive heart beats (RR intervals), influenced by the autonomic nervous system. We intend to review literature showing HRV changes in leukemia subjects. The articles selected in the current review were attained up to March 2018, and the search was limited to articles in English language, published in peer-reviewed journals, with both adult and child age samples. The articles were investigated in the five electronic databases: PubMed, Physiotherapy Evidence Database (PEDro), Cochrane Clinical Trials, Scientific Electronic Library Online (SciELO), and Excerpta Medica dataBASE (EMBASE). Towards the end of the research, 9 studies were included. Subjects undergoing treatment for leukemia have reduced HRV, signifying decreased vagal control of heart rate. The subjects that undertook leukemia treatment and their survivors experienced a reduction in HRV with subsequent recovery, but the recovery time is ill defined. HRV is reduced in leukemia subjects who progress to neuropathy secondary to chemotherapy, accompanied by cardiac dysfunction. We advocate the use of HRV to evaluate autonomic function and decide the treatment to prevent autonomic impairment in leukemia subjects.

Benzene and its effects on cell signaling pathways related to hematopoiesis and leukemia.

Benzene is an environmental toxicant found in many consumer products. It is an established human carcinogen and is known to cause acute myeloid leukemia in adults. Epidemiological evidence has since shown that benzene can cross the placenta and affect the fetal liver. Animal studies have shown that in utero exposure to benzene can increase tumor incidence in offspring. Although there have been risk factors established for acute myeloid leukemia, they still do not account for many of the cases. Clearly then, current efforts to elucidate the mechanism by which benzene exerts its carcinogenic properties have been superficial. Owing to the critical role of cell signaling pathways in the development of an organism and its various organ systems, it seems plausible to suspect that these pathways may have a role in leukemogenesis. This review article assesses current evidence of the effects of benzene on critical hematopoietic signaling pathways. Pathways discussed included Hedgehog, Notch/Delta, Wingless/Integrated, nuclear factor-kappaB and others. Following a review of the literature, it seems that current evidence about the effects of benzene on these critical signaling pathways remains limited. Given the important role of these pathways in hematopoiesis, more attention should be given to them.

Concise Review: Adaptation of the Bone Marrow Stroma in Hematopoietic Malignancies: Current Concepts and Models.

The bone marrow stroma maintains hematopoiesis and coordinately regulates regenerative responses through dynamic interactions with hematopoietic stem and progenitor cells. Recent studies indicate that stromal components in the bone marrow of leukemia patients undergo a process of successive adaptation that in turn exerts dramatic effects on the hematopoietic stem cell compartment and promotes leukemic drug resistance. Therefore, functional changes in discrete marrow stromal populations can be considered an aspect of leukemia biogenesis in that they create an aberrant, self-reinforcing microenvironment. In this review, we will describe the current understanding of the remodeling of the hematopoietic stem cell niche following invasion by leukemia cells. We place emphasis on existing evidence of how mesenchymal stem cells and their progeny facilitate neoplastic growth and describe available models and analytical techniques to understand the conversion of the niche toward disease persistence. Stem Cells 2018;36:304-312.

Validity and reliability of the EQ-5D-5 L in family caregivers of leukemia patients.

PURPOSE: This study aimed to test the validity and reliability of the five-level EuroQol five-dimensional (EQ-5D-5 L) instrument in family caregivers (FCs) of leukemia patients in Heilongjiang of China. METHODS: A cross-sectional survey was conducted on 298 family caregivers (FCs) of leukemia patients from three major cancer centers in the capital city of Heilongjiang province of China. Their dimensional scores of the EQ-5D-5 L were compared with those of the WHOQOL-BREF to test the convergent validity (constructs measuring the same concept) and divergent validity (constructs measuring different concepts) of the EQ-5D-5 L. Repeated surveys were conducted on 271 participants to determine the test-retest reliability of the EQ-5D-5 L. RESULTS: The four physical dimensions (mobility, self-care, usual activities, and pain/discomfort) of the EQ-5D-5 L had moderate or high correlations with the physical health domain of the WHOQOL-BREF, with a correlation coefficient (r) ranging from 0.459 to 0.559. The anxiety/depression dimension of the EQ-5D-5 L had a high correlation (r = 0.667) with the psychological domain of the WHOQOL-BREF. By contrast, lower but still significant physical-to-psychological correlations were found between the two instruments (r ranging from 0.219 to 0.396). In addition, the EQ-5D-5 L dimensional scores showed no or weak correlations with the environment and social domains of the WHOQOL-BREF (r ranging from 0.016 to 0.207). High test-retest reliability (> 0.7) was evident. CONCLUSION: The Chinese version of the EQ-5D-5 L has satisfactory reliability and validity in FCs of leukemia patients. It can be used to elicit utility of health-related quality of life in FCs of leukemia.

Impairment of lung diffusion capacity-a new consequence in the long-term childhood leukaemia survivors.

Childhood leukaemia survivors (CLS) are known to have developed long-term impairment of lung function. The reasons for that complication are only partially known. The aims of this study were to assess pulmonary function in CLS and identify (1) risk factors and (2) clinical manifestations for the impairment of airflow and lung diffusion. The study group included 74 CLS: 46 treated with chemotherapy alone (HSCT-), 28 with chemotherapy and haematopoietic stem cell transplantation (HSCT+), and 84 healthy subjects (control group (CG)). Spirometry and diffusion limit of carbon monoxide (DLCO) tests were performed in all subjects. Ten (14%) survivors had restrictive, five (7%) had obstructive pattern, and 47 (66%) had reduced DLCO. The age at diagnosis, type of transplant, and type of conditioning regimen did not significantly affect the pulmonary function tests. The DLCO%pv were lower in CLS than in CG (p < 0.03) and in the HSCT+ than in the HSCT- survivors (p < 0.05). The pulmonary infection increased the risk of diffusion impairment (OR 5.1, CI 1.16-22.9, p = 0.019). DLCO was reduced in survivors who experienced CMV lung infection (p < 0.001). The main symptom of impaired lung diffusion was poor tolerance of exercise (p < 0.005). The lower lung diffusion capacity is the most frequent abnormality in CLS. HSCT and pulmonary infection, in particular with CMV infection, are strong risk factors for impairment of lung diffusion capacity in CLS. Clinical manifestation of DLCO impairment is poor exercise tolerance. A screening for respiratory abnormalities in CLS seems to be of significant importance.

Pain, sleep patterns and health-related quality of life in paediatric patients with cancer.

PURPOSE: To compare sleep and health-related quality of life (HRQOL) in children and adolescents with cancer who had pain, with those who had no pain during hospitalisation. METHOD: A prospective comparative study was used to collect data from paediatric oncology units in three countries (Portugal, Brazil, USA). Participants (n = 118; 8-18 years) completed the Quality of Life Inventory (PedsQL) Cancer module, which includes a pain subscale, and wore a wrist actigraph for at least 72 hr. RESULTS: Almost half of the participants (48.3%) reported having pain. Sleep patterns were not affected by pain. Girls, adolescents and patients diagnosed with leukaemia/lymphoma who reported pain, had significantly lower HRQOL scores. Low sleep duration and HRQOL were found, irrespectively of pain status. CONCLUSIONS: The low sleep duration and HRQOL score in children and adolescents with cancer highlight the importance of physical and psychosocial nursing interventions during hospitalisation. The mediating effect of gender, age and diagnoses on the relation between pain and HRQOL needs to be further understood.

Sox17 expression confers self-renewal potential and fetal stem cell characteristics upon adult hematopoietic progenitors.

A key question concerns the mechanisms that determine temporal identity in stem cells. Fetal hematopoietic stem cells (HSCs) differ from adult HSCs in terms of gene expression profile, surface marker expression, differentiation, and self-renewal capacity. We previously showed that the transcription factor SOX17 is expressed by fetal, but not adult, HSCs and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study, we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes, including fetal HSC surface markers. Sox17 expression enabled transiently reconstituting adult progenitors to give long-term multilineage reconstitution that resembled fetal hematopoiesis, including increased erythropoiesis, increased myelopoiesis, and decreased lymphopoiesis. Long-term ectopic expression of Sox17 eventually led to leukemogenesis. These data demonstrate that SOX17 is sufficient to confer fetal HSC characteristics to adult hematopoietic progenitors and is therefore a key determinant of fetal HSC identity.

An integrated approach to dissecting oncogene addiction implicates a Myb-coordinated self-renewal program as essential for leukemia maintenance.

Although human cancers have complex genotypes and are genomically unstable, they often remain dependent on the continued presence of single-driver mutations-a phenomenon dubbed "oncogene addiction." Such dependencies have been demonstrated in mouse models, where conditional expression systems have revealed that oncogenes able to initiate cancer are often required for tumor maintenance and progression, thus validating the pathways they control as therapeutic targets. Here, we implement an integrative approach that combines genetically defined mouse models, transcriptional profiling, and a novel inducible RNAi platform to characterize cellular programs that underlie addiction to MLL-AF9-a fusion oncoprotein involved in aggressive forms of acute myeloid leukemia (AML). We show that MLL-AF9 contributes to leukemia maintenance by enforcing a Myb-coordinated program of aberrant self-renewal involving genes linked to leukemia stem cell potential and poor prognosis in human AML. Accordingly, partial and transient Myb suppression precisely phenocopies MLL-AF9 withdrawal and eradicates aggressive AML in vivo without preventing normal myelopoiesis, indicating that strategies to inhibit Myb-dependent aberrant self-renewal programs hold promise as effective and cancer-specific therapeutics. Together, our results identify Myb as a critical mediator of oncogene addiction in AML, delineate relevant Myb target genes that are amenable to pharmacologic inhibition, and establish a general approach for dissecting oncogene addiction in vivo.

Low Body Mass Index Is Associated with Increased Risk of Acute GVHD after Umbilical Cord Blood Transplantation in Children and Young Adults with Acute Leukemia: A Study on Behalf of Eurocord and the EBMT Pediatric Disease Working Party.

Body mass index (BMI) may influence outcomes after allogeneic hematopoietic stem cell transplantation (HSCT). However, the impact of BMI on survival in children undergoing HSCT is not well defined, with conflicting results being reported on this issue. We analyzed 855 patients age 2 to 20 years with diagnosis of acute leukemia who underwent umbilical cord blood transplantation (UCBT) from 1990 to 2015. Patients were classified according to BMI as normal (fifth to 85th percentile), underweight (less than fifth percentile), overweight (85th to 95th percentile), and obese (>95th percentile) using growth charts for age and sex. All patients received single-unit UCBT after a myeloablative conditioning regimen. Diagnosis was acute lymphoblastic leukemia in 68% of the patients. Sixty-one percent of patients (n = 523) were in the normal BMI category, 11% (n = 96) were underweight, 16% (n = 137) overweight, and 12% (n = 99) obese. The cumulative incidence of grade II to IV acute graft-versus-host disease (aGVHD) was 35% (32% to 38%). According to pretransplantation BMI, aGVHD was 46% (33% to 59%) for underweight, 34% (31% to 42%) for normal, 36% (18% to 38%) for overweight, and 27% (15% to 37%) for obese (P = .04). In multivariate analysis, a BMI less than the fifth percentile was associated with higher incidence of acute grade II to IV GVHD compared with normal-BMI patients (hazard ratio, 1.61; 95% confidence interval, 1.15 to 2.26; P = .006). Our results show that being underweight at the time of transplantation is associated with an increased risk of aGVHD, highlighting the importance of nutritional status before UCBT.

Enzooty of non-Hodgkin's malignant lymphoma of Papio hamadryas in Sukhumi monkey colony. Clinical and morphological signs of pre-lymphoma.

Inoculation of hamadryas baboons with blood of leukemia ill people-induced malignant non-Hodgkin's lymphoma in experimental animals for a very considerable latency period. At close contact of inoculated baboons with healthy non-inoculated animals, the lymphoma spread between them. The epidemiological analysis, postmortem examination, histological analysis, tissue culturing, and PCR were used for the diagnostics of lymphoma and pre-lymphoma, purification, identification of STLV-1, and HVP viruses. Characteristic clinical and morphological signs designated by us as pre-lymphoma often precede the lymphoma development. In some cases, pre-lymphoma does not develop in lymphoma because animals die from various diseases and do not reach the point of the lymphoma development. The horizontal transmission of lymphoma arising with the participation of T-lymphotropic retrovirus STLV-1 is shown.

Acid-suppressing Drugs and a Low 1 Level of Antithrombin as Risk Factors for L-Asparaginase-associated Pancreatitis: A Case-control Study in the Japan Association of Childhood Leukemia Study (JACLS).

L-Asparaginase has significantly improved outcome for children with acute lymphoblastic leukemia and has become an essential component of multiagent chemotherapy. However, there are many adverse events due to L-asparaginase, including acute pancreatitis. The pathology of L-asparaginase-associated pancreatitis (AAP) remains unclear. We compared patients who developed AAP (n=29) and random matched controls (n=36) who had been enrolled in the Japan Association of Childhood Leukemia Study of the ALL-02 protocol. AAP and control patients were matched for age, sex, treatment, and protocol risk. We examined correlations between AAP development and clinical symptoms, laboratory data, and concomitant medication. Abdominal pain and nausea were common presenting symptoms for AAP. There was an increased risk of AAP in patients using gastric acid-suppressing agents and antithrombin (AT) supplementation. Mean fibrinogen and AT levels before the onset of AAP were lower in AAP patients than in controls. Decreased AT and fibrinogen levels resulting from the strong suppression of protein synthesis by L-asparaginase were predictive signs for AAP. Our epidemiological approach should prove clinically useful for the diagnosis the AAP as early as possible.

Virtual reality for lumbar puncture in a morbidly obese patient with leukemia.

Virtual reality is an immersive technology that can provide distraction and anxiolysis during painful procedures. While it has been shown to be effective in less invasive procedures, it is underutilized in more invasive procedures. We describe using virtual reality for a morbidly obese patient with leukemia undergoing lumbar puncture. The use of virtual reality reduced the amount of analgesics and anxiolytics and the procedure and recovery times compared with no virtual reality.

Exome array analysis identifies GPR35 as a novel susceptibility gene for anthracycline-induced cardiotoxicity in childhood cancer.

OBJECTIVES: Pediatric cancer survivors are a steadily growing population; however, chronic anthracycline-induced cardiotoxicity (AIC) is a serious long-term complication leading to considerable morbidity. We aimed to identify new genes and low-frequency variants influencing the susceptibility to AIC for pediatric cancer patients. PATIENTS AND METHODS: We studied the association of variants on the Illumina HumanExome BeadChip array in 83 anthracycline-treated pediatric cancer patients. In addition to single-variant association tests, we carried out a gene-based analysis to investigate the combined effects of common and low-frequency variants to chronic AIC. RESULTS: Although no single-variant showed an association with chronic AIC that was statistically significant after correction for multiple testing, we identified a novel significant association for G protein-coupled receptor 35 (GPR35) by gene-based testing, a gene with potential roles in cardiac physiology and pathology (P=7.0×10), which remained statistically significant after correction for multiple testing (PFDR=0.03). The greatest contribution to this observed association was made by rs12468485, a missense variant (p.Thr253Met, c.758C>T, minor allele frequency=0.04), with the T allele associated with an increased risk of chronic AIC and more severe symptomatic cardiac manifestations at low anthracycline doses. CONCLUSION: Using exome array data, we identified GPR35 as a novel susceptibility gene associated with chronic AIC in pediatric cancer patients.