KSHV transactivator-derived small peptide traps coactivators to attenuate MYC and inhibits leukemia and lymphoma cell growth

In herpesvirus replicating cells, host cell gene transcription is frequently down-regulated because important transcriptional apparatuses are appropriated by viral transcription factors. Here, we show a small peptide derived from the Kaposi's sarcoma-associated herpesvirus transactivator (K-Rta) sequence, which attenuates cellular MYC expression, reduces cell proliferation, and selectively kills cancer cell lines in both tissue culture and a xenograft tumor mouse model. Mechanistically, the peptide functions as a decoy to block the recruitment of coactivator complexes consisting of Nuclear receptor coactivator 2 (NCOA2), p300, and SWI/SNF proteins to the MYC promoter in primary effusion lymphoma cells. Thiol(SH)-linked alkylation for the metabolic sequencing of RNA (SLAM seq) with target-transcriptional analyses further confirm that the viral peptide directly attenuates MYC and MYC-target gene expression. This study thus provides a unique tool to control MYC activation, which may be used as a therapeutic payload to treat MYC-dependent diseases such as cancers and autoimmune diseases.

Role of CD47 in Hematological Malignancies

CD47, or integrin-associated protein, is a cell surface ligand expressed in low levels by nearly all cells of the body. It plays an integral role in various immune responses as well as autoimmunity, by sending a potent "don't eat me" signal to prevent phagocytosis. A growing body of evidence demonstrates that CD47 is overexpressed in various hematological malignancies and its interaction with SIRPα on the phagocytic cells prevents phagocytosis of cancer cells. Additionally, it is expressed by different cell types in the tumor microenvironment and is required for establishing tumor metastasis. Overexpression of CD47 is thus often associated with poor clinical outcomes. CD47 has emerged as a potential therapeutic target and is being investigated in various preclinical studies as well as clinical trials to prove its safety and efficacy in treating hematological neoplasms. This review focuses on different therapeutic mechanisms to target CD47, either alone or in combination with other cell surface markers, and its pivotal role in impairing tumor growth and metastatic spread of various types of hematological malignancies.

Sperm DNA integrity in adult survivors of paediatric leukemia and lymphoma: A pilot study on the impact of age and type of treatment

Childhood cancer survivors (CCS) are more likely than siblings to report low sperm count and to use assisted reproductive technologies. Yet, it is still unclear if the sperm produced many years after remission of cancer display DNA and chromatin damage linked to male infertility and poor embryo development. As well, the importance of the age at diagnosis in relation to puberty is poorly understood. In this pilot study, we compared reproductive parameters and sperm damage from adult survivors of childhood leukemia and lymphoma, sub-divided into those diagnosed before or after puberty, to men with no history of cancer. Our data indicate that CCS, independently of the age of diagnosis, have a high risk of low sperm count and when sperm are present, chances of DNA and chromatin abnormalities appear similar to those seen in the general population. Exposure to alkylating agents is correlated with low sperm count whereas exposure to anthracyclines, and doxorubicin in particular, could have long-term consequences on sperm integrity. This study highlights the need for further research on fertility among male CCS and the importance of informing families about the potential long-term impact of chemotherapy on male fertility regardless of age at diagnosis.

Thrombocytopenia in leukemia: Pathogenesis and prognosis

Leukemias, a heterogeneous group of hematological disorders, are characterized by ineffective hematopoiesis and morphologic abnormalities of hematopoietic cells. Thrombocytopenia is a common problem among leukemia types that can lead to hemorrhagic complications in patients. The purpose of this review article is to identify the conditions associated with the incidence of thrombocytopenia in leukemias. It can be stated that although translocations have been considered responsible for this complication in many studies, other factors such as bone marrow failure, genes polymorphism, a mutation in some transcription factors, and the adverse effects of treatment could be associated with pathogenesis and poor prognosis of thrombocytopenia in leukemias. Considering the importance of thrombocytopenia in leukemias, it is hoped that the recognition of risk factors increasing the incidence of this complication in leukemic patients would be useful for prevention and treatment of this disorder.

MLL-fusion-driven leukemia requires SETD2 to safeguard genomic integrity

MLL-fusions represent a large group of leukemia drivers, whose diversity originates from the vast molecular heterogeneity of C-terminal fusion partners of MLL. While studies of selected MLL-fusions have revealed critical molecular pathways, unifying mechanisms across all MLL-fusions remain poorly understood. We present the first comprehensive survey of protein-protein interactions of seven distantly related MLL-fusion proteins. Functional investigation of 128 conserved MLL-fusion-interactors identifies a specific role for the lysine methyltransferase SETD2 in MLL-leukemia. SETD2 loss causes growth arrest and differentiation of AML cells, and leads to increased DNA damage. In addition to its role in H3K36 tri-methylation, SETD2 is required to maintain high H3K79 di-methylation and MLL-AF9-binding to critical target genes, such as Hoxa9. SETD2 loss synergizes with pharmacologic inhibition of the H3K79 methyltransferase DOT1L to induce DNA damage, growth arrest, differentiation, and apoptosis. These results uncover a dependency for SETD2 during MLL-leukemogenesis, revealing a novel actionable vulnerability in this disease.

The role of hypoxia-inducible factors in leukemias

Hypoxia, understood as low partial oxygen pressure, has become one of the most explored fields in recent years. Cellular response to hypoxia is mediated by hypoxia-inducible factors (HIFs) - potent transcription regulators, and their downstream pathways. In general, HIFs modify energy metabolism, inflammation and immune response, enhance cancer invasion, metastasis, resistance to treatment, and relapse. The influence of HIFs on the progression of leukemia is still under investigation in various studies, but in mice and some human models HIFs have been recognized as leukemia immortalizers by promoting leukemic stem cell quiescence and inhibiting their cell cycle. This makes leukemic stem cells resistant to most known treatment approaches. The role of HIFs in solid tumors and leukemia makes them almost ideal targets for an anticancer treatment. Although the first attempts with new molecules are encouraging, there is a need to investigate the ambiguous role of HIFs to develop a modern antileukemic treatment.

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.

Effects of vinegar-egg on growth inhibition, differentiation human leukemic U937 cells and its immunomodulatory activity

Vinegar and eggs have rich nutrients. In this study, the mixed form of both derived products, vinegar–egg solution and its products (vinegar–egg concentrate and vinegar–egg condensate) were chosen for an assessment of their biological activity. To further our understanding regarding the anticancer and immunomodulatory effects of vinegar–egg, we investigated its effects on the proliferation and differentiation of U937 cells. Vinegar–egg was treated using spray drying, freeze drying and vacuum concentration and used to stimulate human mononuclear cells. The conditioned media obtained from these cultures by filtration were used to treat U937 cells. Three conditioned media inhibited U937 cell growth by 22.1–67.25% more effectively than PHA-treated control (22.53%). CD11b and CD14 expression on the treated U937 cells were 29.1–45.4% and 31.6–47.2%, respectively. High levels of cytokines IL-1β, IFN-γ and TNF-α were detected in the three conditioned media. Vinegar–egg stimulates human mononuclear cells to secrete cytokines, which inhibit the growth of U937 cells and induce their differentiation.

Clinicohematological Study of Pancytopenia in a Tertiary Care Hospital of Western Region of Nepal

INTRODUCTION

Pancytopenia is a relatively common hematological entity and is a manifestation of many illnesses which can be life threatening at times. The severity of pancytopenia and the underlying pathology determine the management and prognosis. This study was conducted to evaluate hematological and bone marrow findings in patients presenting with pancytopenia.

METHODS

A prospective observational study was conducted in Department of Pathology, Manipal College of Medical Sciences, Pokhara from January 2011 to December 2016. Clinical and hematological parameters including bone marrow aspiration and biopsy were evaluated in all patients who presented with pancytopenia.

RESULTS

Among 138 cases studied, patients' age ranged from 2 to 82 years with a mean age of 43.95 years, and there was male predominance. Most of the patients presented with generalized weakness, pallor, dypnoea and fever. Hypoplastic marrow was seen in 38 (27.5%) cases, followed by 26 (18.8%) cases of megaloblastic anemia and 19 (13.76%) cases of acute leukemia. Other findings included one case each of hemophagocyosis, leishmaniasis, plasmodium vivex malaria and metastatic carcinoma.

CONCLUSIONS

This study highlights that pancytopenia is a common hematological problem and that the study of detailed primary hematological investigations along with bone marrow study in patients with pancytopenia will help to identify the cause for further planning and management.

Symptom Trajectories in Children Receiving Treatment for Leukemia: A Latent Class Growth Analysis With Multitrajectory Modeling

CONTEXT

Cancer treatment symptoms play a major role in determining the health of children with cancer. Symptom toxicity often results in complications, treatment delays, and therapy dose reductions that can compromise leukemia therapy and jeopardize chances for long-term survival. Critical to understanding symptom experiences during treatment is the need for exploration of "why" inter-individual symptom differences occur; this will determine who may be most susceptible to treatment toxicities.

OBJECTIVES

This study examined specific symptom trajectories during the first 18 months of childhood leukemia treatment. Symptom measures included fatigue, sleep disturbances, pain, nausea, and depression.

METHODS

Symptom trajectories of 236 children with leukemia three to 18 years old were explored prospectively over four periods: initiation of post-induction therapy, four and eight post-induction therapy, and the last time point was at the beginning of maintenance/continuation therapy. Latent class growth analysis was used to classify patients into distinctive groups with similar symptom trajectories based on patients' response patterns on the symptom measures over time.

RESULTS

Three latent classes of symptom trajectories were identified and classified into mild, moderate, and severe symptom trajectories. The only demographic characteristic with a significant relationship to membership in the latent class symptom trajectories was race/ethnicity. All other demographic characteristics including leukemia risk levels showed no significant relationships.

CONCLUSION

This study is unique in that groups of patients with similar symptoms were identified rather than groups of symptoms. Further research using latent class growth analysis is needed.

RAD001 (everolimus) enhances TRAIL cytotoxicity in human leukemic Jurkat T cells by upregulating DR5

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), either alone or in combination with other anti-cancer agents, is a promising new strategy for the treatment of cancer. However, aberrant PI3K/Akt/mTOR survival signaling may confer TRAIL resistance by altering the balance between pro- and anti-apoptotic proteins. In the present study, we showed that the Akt/mTOR inhibitor RAD001 (everolimus) induced cell death in a dose-dependent manner and enhanced TRAIL-induced apoptosis in human leukemic Jurkat T cells, which show PI3K/Akt/mTOR pathway activation and basal expression levels of death receptor (DR) 5 (TRAIL-R2). Investigation of the effect of RAD001 treatment on the expression of TRAIL receptors (TRAIL-Rs) in Jurkat T cells showed that RAD001 significantly upregulated DR5 by up to 51.22%, but not other TRAIL-Rs such as DR4 (TRAIL-R1), decoy receptor (DcR) 1 (TRAIL-R3), and DcR2 (TRAIL-R4). Pretreatment with DR5:Fc chimera abrogated the RAD001-induced increase of TRAIL cytotoxicity, indicating that the upregulation of DR5 by RAD001 plays a role in enhancing the susceptibility of Jurkat T cells to TRAIL. Our results indicate that combination treatment with RAD001 and TRAIL may be a novel therapeutic strategy in leukemia.

Natural compounds and pharmaceuticals reprogram leukemia cell differentiation pathways

In addition to apoptosis resistance and cell proliferation capacities, the undifferentiated state also characterizes most cancer cells, especially leukemia cells. Cell differentiation is a multifaceted process that depends on complex regulatory networks that involve transcriptional, post-transcriptional and epigenetic regulation of gene expression. The time- and spatially-dependent expression of lineage-specific genes and genes that control cell growth and cell death is implicated in the process of maturation. The induction of cancer cell differentiation is considered an alternative approach to elicit cell death and proliferation arrest. Differentiation therapy has mainly been developed to treat acute myeloid leukemia, notably with all-trans retinoic acid (ATRA). Numerous molecules from diverse natural or synthetic origins are effective alone or in association with ATRA in both in vitro and in vivo experiments. During the last two decades, pharmaceuticals and natural compounds with various chemical structures, including alkaloids, flavonoids and polyphenols, were identified as potential differentiating agents of hematopoietic pathways and osteogenesis.

Cell fate reprogramming by control of intracellular network dynamics

Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell’s fate, such as disease therapeutics and stem cell reprogramming. Here we develop a novel network control framework that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our approach drives any initial state to the target state with 100% effectiveness and needs to be applied only transiently for the network to reach and stay in the desired state. We illustrate our method’s potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of helper T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments.

Practical applications in modern molecular and systems biology such as the search for new therapeutic targets for diseases and stem cell reprogramming have generated a great interest in controlling the internal dynamics of a cell. Here we present a network control approach that integrates the structural and functional information of the network. We show that stabilizing the expression or activity of a few select components can drive the cell towards a desired fate or away from an undesired fate. We demonstrate our method’s effectiveness by applying it to a type of blood cell cancer and to the differentiation of a type of immune cell. Overall, our approach provides new insights into how to control the dynamics of intracellular networks.

[Biological mechanisms of human-derived leukemia stem cells senescence regulated by Angelica sinensis polysaccharide]

OBJECTIVE

To explore the biological mechanisms underlying Angelica sindsis polysaccharide (ASP) -induced aging of human-derived leukemia stem cells (LSCs) in vitro.

METHOD

Acute myelogenous leukemia stem cells were isolated by magnetic activated cell sorting (MACS). The ability of LSC proliferation treated by various concentration of ASP(20-80 mg · L(-1)) in vitro for 48 hours were tested using cell counting Kit-8 ( CCK8) , colony forming were evaluated by methylcellulose CFU assay. The ultra structure changes of AML CD34+ CD38- cells were analyzed by transmission electron microscopy. The aging cells were detected with senescence-β-galactosidase Kit staining. Expression of aging-related p53, p21, p16, Rb mRNA and P16, Rb, CDK4 and Cyclin E protein were detected by quantitative reverse transcription polymerase chain reaction( qRT-PCR) and Western blotting, respectively.

RESULT

The purity of the CD34 + CD38 - cells is (91.15 ± 2.41)% after sorted and showed good morphology. The proliferation of LSC was exhibited significantly concentration-dependent inhibited after exposure to various concentration of ASP. Treated by 40 mg · L(-1) ASP for 48 hours, the percentage of positive cells stained by SA-β-Gal was dramatically increased (P < 0.01) and the colony-formed ability has been weakened (P < 0.01). The observation of ultrastructure showed that cell heterochromatin condensation and fragmentation, mitochondrial swelling, lysosomes increased in number. Aging-related p53, p21, p16, Rb and P16, Rb were up-regulated, protein regulatory cell-cycle CDK4 and Cyclin E were down-regulated. ASP may induce the senescence of LSCs effectively in vitro, P16-Rb cell signaling pathway play a significant role in this process.

CONCLUSION

ASP can induce human leukemia stem cell senescence in vitro, the mechanism involved may be related to ASP regulation P16-Rb signaling pathways.

Leukemic Transformation

Leukemia results from the uncontrolled accumulation of primitive, poorly differentiated blood cells, and is a consequence of the accumulation of mutations in hematopoietic precursor cells. These mutations include point mutations (single base pair insertions, deletions, or substitutions), gross chromosomal rearrangements such as deletions, insertions, amplifications, and translocations, and epigenetic changes. It seems likely that mutations affecting at least two pathways are required for the development of leukemia. One of these pathways regulates cell accumulation; the second regulates hematopoietic differentiation. Molecularly targeted therapy, which interrupts functions of the leukemogenic proteins generated by mutations, has been developed and shown to be effective for several forms of malignancy. Therefore, it is our hope and belief that a clearer understanding of the mechanism(s) that underlie leukemic transformation will lead to effective new therapies for this dreaded disease.

Acute leukemia

Although great progress has been made in the understanding and treatment of acute leukemia, this disease has not been conquered. For emergency providers (EPs), the presentation of these patients to an emergency department presents a host of challenges. A patient may present with a new diagnosis of leukemia or with complications of the disease process or associated chemotherapy. It is incumbent on EPs to be familiar with the manifestations of leukemia in its various stages and maintain some suspicion for this diagnosis, given the nebulous and insidious manner in which leukemia can present.

Zerumbone induces G2/M cell cycle arrest and apoptosis via mitochondrial pathway in Jurkat cell line

This investigation determined the anticancer properties of zerumbone (ZER) on the human T-cell (Jurkat) line using the MTT assay, microscopic evaluations, flow cytometric analyses, and caspase activity estimations. The results showed that ZER is selectively cytotoxic to Jurkat cells in a dose and time-dependent manner with IC50 of 11.9 ± 0.2, 8.6 ± 0.5 and 5.4 ± 0.4 μg/mL at 24, 48 and 72 hours of treatment, respectively. ZER did not produce an adverse effect on normal human peripheral blood mononuclear cells (PBMC). ZER is not as cytotoxic as doxorubicin, which imposed an inhibitory effect on Jurkat cells with IC50 of 2.1 ± 0.2, 1.8 ± 0.15, 1.5 ± 0.07 μg/mL after 24, 48 and 72 hours treatment, respectively. ZER significantly (P < 0.05) arrested Jurkat cells at the G2/M phase of the cell cycle. The antiproliferative effect of ZER on Jurkat cells was through the apoptotic intrinsic pathway via the activation of caspase-3 and -9. The results showed that ZER can be further developed into a safe chemotherapeutic compound for the treatment of cancers, especially leukemia.

Hematological malignancies: disease pathophysiology of leukemic stem cells

Hematopoietic homeostasis is maintained throughout the lifetime of an individual through self-renewal of hematopoietic stem cells. Defects in the self - renewal and differentiation lead to hematopoietic insufficiency and development of malignancies. Leukemic stem cells (LSCs), which are considered to originate from hematopoietic stem or progenitor cells, not only adopt the regulatory machinery operating in normal HSCs but establish their own mechanisms against apoptosis and senescence. Hematopoietic malignancies are of Lymphoid origin with CLL and ALL and myeloid malignancies with AML and CML and in addition there are disease of the plasma multiple myelomas. One of the major therapeutic strategies for hematological malignancies is hematopoietic stem cell transplantation along with combination of chemotherapy. The review gives an insight of different hematological malignancies, the mechanism and therapeutic strategies available at present.

[Experimental study on aging effect of Angelica sinensis polysaccharides combined with cytarabine on human leukemia KG1alpha cell lines]

The latest findings of our laboratory showed that Angelica sinensis polysaccharide (ASP) showed a definite effect in regulating the aging of hematopoietic stem cells. Leukemia is a type of malignant hematopoietic tumor in hematopoietic stem cells. There have been no relevant reports about ASP's effect in regulating the aging of leukemia cells. In this study, human acute myeloid leukemia (AML) KG1alpha cell lines in logarithmic growth phase were taken as the study object, and were divided into the ASP group, the cytarabine (Ara-C) group, the ASP + Ara-C group and the control group. The groups were respectively treated with different concentration of ASP, Ara-C and ASP + Ara-C for different periods, with the aim to study the effect of ASP combined with Ara-C in regulating the aging of human acute myeloid leukemia KG1alpha cell lines and its relevant mechanism. The results showed that ASP, Ara-C and ASP + Ara-C could obviously inhibit KG1alpha cell proliferation in vitro, block the cells in G0/G1 phase. The cells showed the aging morphological feature. The percentage of positive stained aging cells was dramatically increased, and could significantly up-regulate the expression of aging-related proteins P16 and RB, which were more obvious in the ASP + Ara-C group. In conclusion, the aging mechanism of KG1alpha cell induced by ASP and Ara-C may be related to the regulation of the expression of aging-related proteins, suggesting that the combined administration of ASP and anticancer drugs plays a better role in the treatment of leukemia .

Functions and diseases of red and white blood cells

Red and white blood cells have two main functions: the carriage of oxygen; and defence against microbial attack. The full blood count is one of the most frequently requested routine blood tests; it provides key indices such as haemoglobin and the number of white cell subsets, and provides information to aid diagnosis of a range of conditions, including anaemia, infection, leukaemia, myeloma and lymphoma.

Progress in defining multidrug resistance in leukemia

Multidrug resistance (MDR) is a naturally occurring defense phenomenon by which cells battle against chemically foreign substances (xenobiotics), including some cytotoxic drugs. Membrane transporter hyperactivity is a major contributor to MDR and is the primary target of both diagnostic and therapeutic interventions. Multi-xenobiotic resistance can be exploited as several fluorescent indicator probes are extruded by the same drug transporters, making it possible to quantitatively measure MDR activity in cell lines and clinical samples by flow cytometry. The literature on MDR is reported in a number of different formats, making it difficult to compare data from various groups. This article will briefly review the pathomechanism, then focus upon the diagnostic approach, the interpretation of results from clinical samples and correlations with other variables. The authors believe that a standardized MDR assay, as well as a suitable monitoring test, may become a prognostic marker in several types of leukemia.

Ursolic acid induces U937 cells differentiation by PI3K/Akt pathway activation

AIM

Ursolic acid (UA), a pentacyclic triterpenoid, is used as an anti-inflammatory and anti-cancer agent. There were few studies on the effects of UA on differentiation, and this is the first time to elucidate the potential effect and molecular mechanism of UA on inducing differentiation in the human leukemia cell line U937.

METHODS

Wright-Giemsa staining, nitroblue tetrazolium reduction assay and flow cytometric analysis were utilized to demonstrate the differentiation of U937 cells induced by UA. Western blotting and immunofluorescence assay were used to investigate the possible mechanism.

RESULTS

It was found that UA could induce the differentiation of U937cells and Akt-activity was significantly increased during differentiation. Additionally, LY294002, a PI3K-Akt inhibitor, could block the differentiation of U937 cells induced by UA.

CONCLUSION

UA could induce the differentiation of U937 cells by activating the PI3K/Akt pathway, and it could be a potential candidate as a differentiation-inducing agent for the therapy of leukemia.

Cordycepin regulates GSK-3β/β-catenin signaling in human leukemia cells

BACKGROUND

Leukemia stem cells (LSCs) are a limitless cell source for the initiation and maintenance of leukemia. Activation of the Wnt/β-catenin pathway is required for the survival and development of LSCs. Therefore, targeting β-catenin is considered a therapeutic strategy for the treatment of leukemia. The goal of this study was to explore whether cordycepin, an active component of the traditional medicine Cordyceps sinensis, regulates β-catenin expression in leukemia cells.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study, we found that cordycepin significantly suppressed cell proliferation in all malignant cancer cells, including U937, K562, A549, HepG2, SK-Hep1 and MCF7 in a dose-dependent manner. However, cordycepin reduced β-catenin levels in U937, K562 and THP1 leukemia cells and had no effect on other solid cancer cells. In addition, treatment with cordycepin significantly suppressed leukemia colony formation in soft agar assay. Cordycepin enhanced proteasome-dependent degradation and inhibited nuclear translocation of β-catenin in leukemia cells. Cordycepin-reduced β-catenin stability was restored by the addition of a pharmacological inhibitor of GSK-3β, indicating that cordycepin-suppressed β-catenin stability is mediated by the activation of GSK-3β. Furthermore, cordycepin abolished the effect of Wnt3a-induced β-catenin in leukemia cells. In addition, cordycepin-impaired β-catenin is regulated by Akt activation but is not significantly influenced by AMPK or mTOR signal pathways.

SIGNIFICANCE

Our findings show for the first time that codycepin selectively reduces β-catenin stability in leukemia but not in other solid tumor cells. This suppressive effect is mediated by regulating GSK-3β. A synergistic combination of cordycepin with other treatments should be used as a novel strategy to eradicate leukemia via elimination of LSCs.

Roles of Rho GTPases in leucocyte and leukaemia cell transendothelial migration

Leucocytes migrate into and out of blood vessels at multiple points during their development and maturation, and during immune surveillance. In response to tissue damage and infection, they are rapidly recruited through the endothelium lining blood vessels into the tissues. Leukaemia cells also move in and out of the bloodstream during leukaemia progression. Rho GTPases are intracellular signalling proteins that regulate cytoskeletal dynamics and are key coordinators of cell migration. Here, we describe how different members of the Rho GTPase family act in leucocytes and leukaemia cells to regulate steps of transendothelial migration. We discuss how inhibitors of Rho signalling could be used to reduce leucocyte or leukaemia cell entry into tissues.

Possible health benefits from reducing occupational magnetic fields

BACKGROUND

Magnetic fields (MF) from AC electricity are a Possible Human Carcinogen, based on limited epidemiologic evidence from exposures far below occupational health limits.

METHODS

To help formulate government guidance on occupational MF, the cancer cases prevented and the monetary benefits accruing to society by reducing workplace exposures were determined. Life-table methods produced Disability Adjusted Life Years, which were converted to monetary values.

RESULTS

Adjusted for probabilities of causality, the expected increase in a worker's disability-free life are 0.04 year (2 weeks) from a 1 microtesla (µT) MF reduction in average worklife exposure, which is equivalent to $5,100/worker/µT in year 2010 U.S. dollars (95% confidence interval $1,000-$9,000/worker/µT). Where nine electrosteel workers had 13.8 µT exposures, for example, moving them to ambient MFs would provide $600,000 in benefits to society (uncertainty interval $0-$1,000,000).

CONCLUSIONS

When combined with the costs of controls, this analysis provides guidance for precautionary recommendations for managing occupational MF exposures.

On optimal and suboptimal treatment strategies for a mathematical model of leukemia

In this work an optimization problem for a leukemia treatment model based on the Gompertzian law of cell growth is considered. The quantities of the leukemic and of the healthy cells at the end of the therapy are chosen as the criterion of the treatment quality. In the case where the number of healthy cells at the end of the therapy is higher than a chosen desired number, an analytical solution of the optimization problem for a wide class of therapy processes is given. If this is not the case, a control strategy called alternative is suggested.

In vitro suppression of growth of murine WEHI-3 leukemia cells and in vivo promotion of phagocytosis in a leukemia mice model by indole-3-carbinol

Indole-3-carbinol (I3C), a potential anticancer substance, can be found in cruciferous (cabbage family) vegetables, mainly cauliflower and Chinese cabbage. However, the bioactivity of I3C on the apoptotic effects of murine leukemia WEHI-3 cells and promotion of immune responses in leukemia mice model are unclear. In this study, we investigated the effect of I3C on cell-cycle arrest and apoptosis in vitro and immunomodulation in vivo. I3C decreased the viable WEHI-3 cells and caused morphological changes in a concentration- and time-dependent manner. I3C also led to G0/G1 phase arrest, decreased the levels of cyclin A, cyclin D, and CDK2, and increased the level of p21(WAF1/CIP1). Flow cytometric analyses further proved that I3C promoted ROS and intracellular Ca(2+) production and decreased the levels of ΔΨ(m) in WEHI-3 cells. Cells after exposure to I3C for 24 h showed DNA fragmentation and chromatin condensation. Comet assay also indicated that I3C induced DNA damage in examined cells. I3C increased the levels of cytochrome c, FADD, GADD153, GRP78, and caspase-12 as well as induced activities of caspase-3, -8, and -9. Moreover, I3C attenuated NF-κB DNA binding activity in I3C-treated WEHI-3 cells as shown by EMSA and Western blotting analyses. In the in vivo study, we examined the effects of I3C on WEHI-3 leukemia mice. Results showed that I3C increased the level of T cells and decreased the level of macrophages. I3C also reduced the weights of liver and spleen, and it promoted phagocytosis by macrophages as compared to the nontreated leukemia mice group. On the basis of our results, I3C affects murine leukemia WEHI-3 cells both in vitro and in vivo.

[Experimental study on human leukemia cell line K562 senescence induced by ginsenoside Rg1]

OBJECTIVE

To observe the effect and mechanism of ginsenoside Rg1 in inducing senescence human leukemia K562 cell line.

METHOD

Proliferation of K562 cell line induced by Rg1 was detected by MTT colorimetric test for the purpose to screen optimal active concentration and time (20 micromol x L(-1) , 48 h). Impact of Rg1 on cell cycle was analyzed using flow cytometry. The percentage of staining positive cells was detected by SA-beta-Gal staining. The expressions of senescence-related genes such as p16, p53, p21, Rb, were detected by RT-PCR and the changes in ultramicro-morphology were observed by transmission electron microscopy.

RESULT

Rg1 can significantly inhibit the proliferation of K562 cells in vitro and arrest the cells in G2/M phase. The percentage of positive cells stained by SA-beta-Gal was dramatically increased (P < 0.05) and the expression of cell senescence-related genes were up-regulated. The observation of ultrastructure showed that cell volume increase, heterochromatin condensation and fragmentation, mitochondrial volume increase, lysosomes increase in size and number.

CONCLUSION

Rg1 can induce the senescence of leukemia cell line K562 and play an important role in regulating p53-p21-Rb, p16-Rb cell signaling pathway.

[WNT-β-catenin signaling pathway and its relationship with cancer]

The Wnt-β-catenin signalling pathway plays a crucial role in the regulation, differentiation, proliferation and cellular death processes; consequently, alterations in this pathway are involved in numerous abnormalities of development, growth and homeostasis in animal organisms. Wnt proteins include a numerous family of secretion glycoproteins which join to Frizzled receptors and Low Density Lipoprotein Receptor-related Protein, in order to stabilize the critical β-catenin protein, and to initiate an intricate signaling cascade, which is related to multiple nucleocytoplasmatic processes. Alterations in the canonical Wnt-β-catenin signaling pathway have been associated with variations in a number of proteins participating in this route, or with activation / inactivation of oncogenes and tumor suppressor genes, which explain different processes of tumorigenesis, in addition to a number of malformations and human diseases. This review describes the relations between the Wnt-β-catenin signaling pathway with different neoplasic processes, as well as its application in the diagnosis and prognosis of cancer.

Acute appendicitis in children with acute leukemia: experiences of a single institution in Korea

PURPOSE

Acute appendicitis has been reported to be relatively rare in pediatric leukemia patients but there is no official data for this in Korea. And there is no consensus for its treatment in this population.

MATERIALS AND METHODS

We conducted a retrospective study of 7 patients diagnosed with appendicitis among 1209 pediatric patients who were diagnosed with leukemia from 1996 to 2008 at a single institution in Korea.

RESULTS

The median age at the time of the diagnosis of appendicitis was 12 years (range: 3-15 years), and 3 of the patients were male. The median absolute neutrophil count (ANC) at the time of diagnosis was 0.99×10⁹/L (range: 0-3×10⁹/L). The mean time from the onset of symptoms to the diagnosis was 4 days. All 7 leukemia patients with appendicitis underwent surgery and they demonstrated a survival of 100% without significant complications.

CONCLUSION

The incidence of appendicitis in pediatric leukemia patients was 0.57% in our study. Early diagnosis with abdominal ultrasound or computed tomography and early surgical resection in leukemic patient with acute appendicitis may be a safer and more effective treatment option. Even when perforation has already occurred and when the patient has an ANC of 0×10⁹/L, surgical treatment may improve overall survival without incurring significant complications.

[Magnetic resonance imaging and spectroscopy of the bone marrow in children with common hematological diseases]

OBJECTIVE

To evaluate the magnetic resonance (MR) imaging and proton magnetic resonance spectroscopy ((1)H-MRS) in the diagnoses of pediatric hematological diseases.

METHODS

A total of 35 cases with pediatric hematological diseases were confirmed by bone marrow puncturing. There were acute leukemia (n = 26), aplastic anemia (n = 6), thalassemia (n = 2) and autoimmune hemolytic anemia (n = 1). Thirty age-marched healthy children underwent MR imaging (T(1)WI, T(2)WI, STIR) and (1)H-MRS of lumber spine and ilium. The lumber spines and iliums were studied by observation of MR imaging and calculation of fat fraction (FF%).

RESULTS

Two patterns were classified by MR imaging and (1)H-MRS in lumber spines and iliums of all cases. Pattern 1: hyperplasia of bone marrow (BM). There were acute leukemia (n = 26), thalassemia (n = 2) and autoimmune hemolytic anemia (n = 1). The manifestations included homogeneous low signal intensity (SI) on T(1)WI, homogeneous low SI on T(2)WI, high SI on STIR and high water peak and low fat peak on (1)H-MRS. The FF%s of Regions of Interest (ROI) in lumber 4s and left iliums of 26 cases with acute leukemia were 0%, of 3 cases with thalassemia or autoimmune hemolytic anemia were 5.02% and 3.70%. Pattern 2: inhibition of BM. There were 6 cases of aplastic anemia. The manifestations included homogeneous or inhomogeneous high SI on T(1)WI and T(2)WI, homogeneous or inhomogeneous low SI on STIR, and low water peak and high fat peak on (1)H-MRS. FF%s of ROI in lumber 4s and left iliums for 6 cases of aplastic anemia were 74.69% and 91.51%. FF% in all groups had significant differences according to the Mann-Whitney test (P < 0.05).

CONCLUSIONS

MR imaging and (1)H-MRS may serve as a noninvasive method for checking hematopoietic status of bone marrow in pediatric hematological diseases.

Exploiting mitochondrial dysfunction for effective elimination of imatinib-resistant leukemic cells

Challenges today concern chronic myeloid leukemia (CML) patients resistant to imatinib. There is growing evidence that imatinib-resistant leukemic cells present abnormal glucose metabolism but the impact on mitochondria has been neglected. Our work aimed to better understand and exploit the metabolic alterations of imatinib-resistant leukemic cells. Imatinib-resistant cells presented high glycolysis as compared to sensitive cells. Consistently, expression of key glycolytic enzymes, at least partly mediated by HIF-1α, was modified in imatinib-resistant cells suggesting that imatinib-resistant cells uncouple glycolytic flux from pyruvate oxidation. Interestingly, mitochondria of imatinib-resistant cells exhibited accumulation of TCA cycle intermediates, increased NADH and low oxygen consumption. These mitochondrial alterations due to the partial failure of ETC were further confirmed in leukemic cells isolated from some imatinib-resistant CML patients. As a consequence, mitochondria generated more ROS than those of imatinib-sensitive cells. This, in turn, resulted in increased death of imatinib-resistant leukemic cells following in vitro or in vivo treatment with the pro-oxidants, PEITC and Trisenox, in a syngeneic mouse tumor model. Conversely, inhibition of glycolysis caused derepression of respiration leading to lower cellular ROS. In conclusion, these findings indicate that imatinib-resistant leukemic cells have an unexpected mitochondrial dysfunction that could be exploited for selective therapeutic intervention.

Assessing the resting energy expenditure of cancer patients in the Penang General Hospital

INTRODUCTION

Malnutrition is common in cancer patients. Generally, it is believed that the resting energy expenditure (REE) is elevated in cancer patients and this contributes to the development of malnutrition. Thus, to be able to assess the REE is important in planning adequate nutrition support.

METHODS

A cross-sectional study was carried out to assess the REE in patients with solid tumour (n=25), leukemia (n=25) and healthy subjects (n=50) by using the indirect calorimetry method under standard conditions.

RESULTS

There was no significant difference between the measured REE among patients with solid tumour, leukemia and the control group (p=0.534). By contrast, there was a significant difference between the REE/kg FFM in solid tumour patients compared to the leukemia group and the healthy subjects, (p=0.049 and p=0.002). The REE derived from the Harris Benedict Equation was found to be significantly higher than the measured REE. The stress factor for patients with solid tumour was 1.35 and that for leukemia patients was 1.36.

CONCLUSION

The REE/kg FFM in the cancer patients undergoing anticancer therapy appeared to be higher than expected compared to healthy subjects. The Harris Benedict Equation (HBE) was found to over-estimate the REE of cancer patients in the study. As the total energy expenditure (TEE) is estimated by multiplying the REE with the stress factor and physical activity factor, the overestimated REE from HBE will further increase the risk of overfeeding in this population.

Stem cell niches and other factors that influence the sensitivity of bone marrow to radiation-induced bone cancer and leukaemia in children and adults

PURPOSE

This paper reviews and reassesses the internationally accepted niches or 'targets' in bone marrow that are sensitive to the induction of leukaemia and primary bone cancer by radiation.

CONCLUSIONS

The hypoxic conditions of the 10 μm thick endosteal/osteoblastic niche where preleukemic stem cells and hematopoietic stem cells (HSC) reside provides a radioprotective microenvironment that is 2- to 3-fold less radiosensitive than vascular niches. This supports partitioning the whole marrow target between the low haematological cancer risk of irradiating HSC in the endosteum and the vascular niches within central marrow. There is a greater risk of induced bone cancer when irradiating a 50 μm thick peripheral marrow adjacent to the remodelling/reforming portion of the trabecular bone surface, rather than marrow next to the quiescent bone surface. This choice of partitioned bone cancer target is substantiated by the greater radiosensitivity of: (i) Bone with high remodelling rates, (ii) the young, (iii) individuals with hypermetabolic benign diseases of bone, and (iv) the epidemiology of alpha-emitting exposures. Evidence is given to show that the absence of excess bone-cancer in atomic-bomb survivors may be partially related to the extremely low prevalence among Japanese of Paget's disease of bone. Radiation-induced fibrosis and the wound healing response may be implicated in not only radiogenic bone cancers but also leukaemia. A novel biological mechanism for adaptive response, and possibility of dynamic targets, is advocated whereby stem cells migrate from vascular niches to stress-mitigated, hypoxic niches.

[State of the endothelium and hemostasis in acute leukemia]

The review presents modern conceptions of disturbances in endothelial lining of the vessels and plasmic hemostasis in patients with acute leukemia; different mechanisms of coagulation disorders in acute leukemia: effects of leukemic cells containing procoagulants, fibrinolytic and antifibrinolytic substances, of intensive chemotherapy and inflammation. All these impacts impair endothelial cells and trigger plasmic coagulation cascade; the initiator of coagulation is a tissue factor. Mechanisms of this process and statistics of thrombohemorrhagic complications in different variants of acute leukemia are outlined.

Gadd45 stress sensors in malignancy and leukemia

Gadd45 proteins, including Gadd45a, Gadd45b, and Gadd45g, have been implicated in stress signaling in response to physiological and environmental stress, including oncogenic stress, which can result in cell cycle arrest, DNA repair, cell survival, senescence, and apoptosis. The function of Gadd45 as a stress sensor is mediated via a complex interplay of physical interactions with other cellular proteins implicated in cell cycle regulation and the response of cells to stress, notably PCNA, p21, cdc2/cyclinB1, and the p38 and JNK stress response kinases. Altered expression of Gadd45 has been observed in multiple types of solid tumors as well as in hematopoietic malignancies. Using genetically engineered mouse models and bone-marrow transplantation, evidence has been obtained indicating that Gadd45 proteins can function to either promote or suppress tumor development and leukemia; this is dependent on the molecular nature of the activated oncogene and the cell type, via engagement of different signaling pathways.

Arachidin-1, a peanut stilbenoid, induces programmed cell death in human leukemia HL-60 cells

The stilbenoids, arachidin-1 (Ara-1), arachidin-3, isopentadienylresveratrol, and resveratrol, have been isolated from germinating peanut kernels and characterized as antioxidant and anti-inflammatory agents. Resveratrol possesses anticancer activity, and studies have indicated that it induces programmed cell death (PCD) in human leukemia HL-60 cells. In this study, the anticancer activity of these stilbenoids was determined in HL-60 cells. Ara-1 had the highest efficacy in inducing PCD in HL-60 cells, with an approximately 4-fold lower EC50 than resveratrol. Ara-1 treatment caused mitochondrial membrane damage, activation of caspases, and nuclear translocation of apoptosis-inducing factor, resulting in chromosome degradation and cell death. Therefore, Ara-1 induces PCD in HL-60 cells through caspase-dependent and caspase-independent pathways. Ara-1 demonstrates its efficacy as an anticancer agent by inducing caspase-independent cell death, which is an alternative death pathway of cancer cells with mutations in key apoptotic genes. These findings indicate the merits of screening other peanut stilbenoids for anticancer activity.

The leukemia-associated Mllt10/Af10-Dot1l are Tcf4/β-catenin coactivators essential for intestinal homeostasis

Wnt signaling maintains the undifferentiated state of intestinal crypt progenitor cells by inducing the formation of nuclear TCF4/β-catenin complexes. In colorectal cancer, activating mutations in Wnt pathway components cause inappropriate activation of TCF4/β-catenin-driven transcription. Despite the passage of a decade after the discovery of TCF4 and β-catenin as the molecular effectors of the Wnt signal, few transcriptional activators essential and unique to the regulation of this transcription program have been found. Using proteomics, we identified the leukemia-associated Mllt10/Af10 and the methyltransferase Dot1l as Tcf4/β-catenin interactors in mouse small intestinal crypts. Mllt10/Af10-Dot1l, essential for transcription elongation, are recruited to Wnt target genes in a β-catenin-dependent manner, resulting in H3K79 methylation over their coding regions in vivo in proliferative crypts of mouse small intestine in colorectal cancer and Wnt-inducible HEK293T cells. Depletion of MLLT10/AF10 in colorectal cancer and Wnt-inducible HEK293T cells followed by expression array analysis identifies MLLT10/AF10 and DOT1L as essential activators to a large extent dedicated to Wnt target gene regulation. In contrast, previously published β-catenin coactivators p300 and BRG1 displayed a more pleiotropic target gene expression profile controlling Wnt and other pathways. tcf4, mllt10/af10, and dot1l are co-expressed in Wnt-driven tissues in zebrafish and essential for Wnt-reporter activity. Intestinal differentiation defects in apc-mutant zebrafish can be rescued by depletion of Mllt10 and Dot1l, establishing these genes as activators downstream of Apc in Wnt target gene activation in vivo. Morpholino-depletion of mllt10/af10-dot1l in zebrafish results in defects in intestinal homeostasis and a significant reduction in the in vivo expression of direct Wnt target genes and in the number of proliferative intestinal epithelial cells. We conclude that Mllt10/Af10-Dot1l are essential, largely dedicated activators of Wnt-dependent transcription, critical for maintenance of intestinal proliferation and homeostasis. The methyltransferase DOT1L may present an attractive candidate for drug targeting in colorectal cancer.

Induction of apoptosis by [8]-shogaol via reactive oxygen species generation, glutathione depletion, and caspase activation in human leukemia cells

Ginger, the rhizome of Zingiber officinale , is a traditional medicine with a carminative effect and antinausea, anti-inflammatory, and anticarcinogenic properties. This study examined the growth inhibitory effects of [8]-shogaol, one of the pungent phenolic compounds in ginger, on human leukemia HL-60 cells. It demonstrated that [8]-shogaol was able to induce apoptosis in a time- and concentration-dependent manner. Treatment with [8]-shogaol caused a rapid loss of mitochondrial transmembrane potential, stimulation of reactive oxygen species (ROS) production, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 and procaspase-3 processing. Taken together, these results suggest for the first time that ROS production and depletion of glutathione that contributed to [8]-shogaol-induced apoptosis in HL-60 cells.

Measurements of oxidative stress status and antioxidant activity in chronic leukaemia patients

There is an interactive relationship between leukaemia and oxidative stress. Leukaemic cells produce larger amounts of reactive oxygen species (ROS) than non-leukaemic cells as they are under a continual state of oxidative siege. So, this study was performed on 20 patients with chronic leukaemia from the Oncology Centre, Mansoura University. We measured leucocytic H2O2 concentrations and lipid peroxidation as serum malondialdehyde (MDA) concentration, serum total antioxidant activity, plasma ascorbic acid and dehydroascorbic acid concentrations, blood reduced glutathione concentration, haemolysate G6PD activity, blood catalase activity, serum superoxide dismutase (SOD) activity and serum anti-dsDNA concentration. We found that chronic leukaemia patients showed a significant increase (P &lt; 0.05) in leucocytic H2O2, serum MDA concentration and total anti-oxidant activity either before or after treatment as compared with control group. Also, there was a significant increase in the other parameters (glutathione, catalase and SOD) either before or after treatment, but we found a significant decrease in ascorbic acid concentration and G6PD activity. There was a significant increase in anti-dsDNA concentration either before or after treatment. It can be concluded that leukaemic patients produce larger amounts of ROS than non-leukaemic patients. Also, the increase in antioxidant activity in leukaemic patients is not high enough to counteract the harmful effects of free radicals. This scenario becomes worse after administration of chemotherapy.

Blood cell generation from the hemangioblast

Understanding how blood cells are generated is important from a biological perspective but also has potential implications in the treatment of blood diseases. Such knowledge could potentially lead to defining new conditions to amplify hematopoietic stem cells (HSCs) or could translate into new methods to produce HSCs, or other types of blood cells, from human embryonic stem cells or induced pluripotent stem cells. Additionally, as most key transcription factors regulating early hematopoietic development have also been implicated in various types of leukemia, understanding their function during normal development could result in a better comprehension of their roles during abnormal hematopoiesis in leukemia. In this review, we discuss our current understanding of the molecular and cellular mechanisms of blood development from the earliest hematopoietic precursor, the hemangioblast, a precursor for both endothelial and hematopoietic cell lineages.

Frequency-domain analysis of the signal-averaged electrocardiogram in hematological malignancies survivors

OBJECTIVES

The aim of the presented study was to evaluate the frequency-domain signal-averaged ECGs (SAECG) abnormalities in childhood and adolescence acute leukemia and lymphoma survivors treated either with or without anthracyclines (ANT) containing chemotherapy in comparison with healthy volunteers.

BACKGROUND

The late development of chemotherapy-induced myocardial complications becomes an issue as the number of childhood cancer survivors is increasing. Underlying cardiac impairment may progress to serious cardiac diseases. Therefore, an early identification of myocardial injury is essential. PATIENTS AMD METHODS: Study population was divided into two treatment groups: ANT group (31 patients previously treated with ANT), and non-ANT group (32 patients who underwent chemotherapy without ANT, both more than 5 years ago). SAECG was added to routine cardiology examination in the whole population study and 32 controls. Using the frequency-domain analysis within the QRS complex a ratio (AR) of 20-50 (Hz)/0-20 (Hz) was calculated.

RESULTS

AR 20-50/0-20 in SAECG was significantly higher in ANT and non-ANT groups, relative to controls (262.5 p < 0.00001 vs. 135.9 p < 0.001 vs. 74.7). The difference between both patient groups was also evident p < 0.01.

CONCLUSION

Significant differences in frequency-domain SAECG parameters between patients (with or without anthracyclines) and controls might indicate the increased risk of electrical instability particularly in anthracycline-treated patients (Tab. 2, Fig. 1, Ref. 34).

The experiences of cancer-related fatigue among Chinese children with leukaemia: a phenomenological study

BACKGROUND

Although cancer-related fatigue has been given priority status for study in Western countries, unfortunately, it has not received enough attention in China. Based on a different cultural perspective, qualitative study regarding cancer-related fatigue in China can provide a cultural context for enriching the system of knowledge about fatigue.

OBJECTIVES

To explore the real-life experiences of fatigue from the perspectives of Chinese Children with leukaemia.

DESIGN

A phenomenological study.

SETTING

A paediatric haematology oncology department of a regional tertiary children's hospital in Shanghai, China.

PARTICIPANTS

A total of 14 children and adolescents with leukaemia, aged 7-18 years old, without known psychiatric or developmental disorders, was selected by purposive sampling.

METHODS

Four focus group interviews were conducted with nine open-ended, semi-structured questions.

FINDINGS

Cancer-related fatigue is a common and distressing issue for Chinese children and adolescents with leukaemia. Three themes were finally generated: 'fatigue is an open interpretation among children and adolescents', 'fatigue is not a single-dimensional aspect', and 'struggles with fatigue and balancing life suffering'. Fatigue, which is closely related to physical, psychological and situational factors, has negative affects on the participants physically, psychologically and on their cognitive well-being, and can impact the family, school and social interaction of children with leukaemia.

CONCLUSIONS

Children and adolescents could easily distinguish cancer-related fatigue from normal fatigue. The participants' message to health professionals is that fatigue is a multidimensional and multifactorial symptom that should be comprehensively understood and managed. The findings provide insight and direction for clinical practice and research regarding intervention development and education plans for cancer-related fatigue for paediatric oncology patients.

A glycoprotein extracted from golden oyster mushroom Pleurotus citrinopileatus exhibiting growth inhibitory effect against U937 leukemia cells

Mushrooms have become popular sources of natural antitumor, antiviral, antibacterial, antioxidative, and immunomodulatory agents. Golden oyster mushroom, Pleurotus citrinopileatus , is a common mushroom in oriental countries for human consumption. We isolated a functional protein (PCP-3A) from the fresh fruiting body of this mushroom. The isolation procedure included ammonium sulfate fractionation, DEAE-Sepharose CL-6B ion exchange chromatography, and Sephacryl S-300 gel filtration. Electrophoresis demonstrated that PCP-3A is a glycoprotein composed of 10 subunits, each approximately 45.0 kDa in size. In vitro cell study showed that PCP-3A at a concentration about 12.5 microg/mL inhibits the proliferation of human tumor cell line U937, in a time- dependent manner (24, 48, and 72 h). It failed to agglutinate rabbit and human erythrocytes, excluding its possibility from being a lectin. Flow cytometry revealed that it is capable of inhibiting the growth of U937 cells by way of S phase arrest and apoptotic induction. We suggest that PCP-3A is worth further investigating for antitumor use.

[Effect of YB-1 gene knockdown on human leukemia cell line K562/A02]

OBJECTIVE

To investigate the potential effects of YB-1 gene knockdown on gene expression profile, cell growth and apoptosis in leukemia cell line K562/A02.

METHODS

The recombinant eukaryotic expression plasmid containing YB-1 short hairpin RNA (shRNA) or random-sequence (HK) were transfected into K562/A02 cells by lipofectamine mediation. cDNA microarray was performed to explore the alteration of gene expression profile when YB-1 gene expression was decreased. Expression of CARD8 and RHOC genes were verified by semi-quantitative reverse transcription-PCR (RT-PCR). The proliferative ability of the cells was determined by methyl thiazolyltetrazolium (MTT) assay and cell cycle analysis. Cell apoptosis was assayed by Annexin V-FITC/PI double labeled flow cytometry.

RESULTS

The levels of YB-1 mRNA and protein decreased dramatically in three positively transfected cells when compared with untransfected K562/A02 cells or K562/A02-HK thansfected cells. Gene expression profile was altered by transfection of YB-1 shRNA into K562/A02 cells. Among 47,000 genes on the microarray, 252 genes were detected to have changes, with 143 down-regulated and 109 up-regulated. They were functionally related to cell cycle progression, gene replication, metabolism, cell apoptosis, cell signal transduction, etc. An increase in CARD8 gene expression and a decrease in RHOC gene expression have been confirmed by RT-PCR in K562/A02-YBX13 cells. The introduction of exogenous YB-1 shRNA gene into K562/A02 cells resulted in decreased proliferation, higher G1, lower G2 and S ratio in cell cycle distribution in comparison with the control groups. Annexin V/PI detection indicated higher Annexin V+ ratio in the three positively transfected cells 24 hours after cells were treated with 0.5 micromol/L of As2O3.

CONCLUSION

Down-regulation of YB-1 gene by shRNA-YB-1 can alter the gene expression profile in K562/A02 cells, leading to change of cell proliferation and apoptosis.