Expression and Function of Leptin Receptor Isoforms in Myeloid Leukemia and Myelodysplastic Syndromes: Proliferative and Anti-Apoptotic Activities

Identification and validation of obesity-related gene LEP methylation as a prognostic indicator in patients with acute myeloid leukemia

BACKGROUND

Obesity confers enhanced risk for multiple diseases including cancer. The DNA methylation alterations in obesity-related genes have been implicated in several human solid tumors. However, the underlying role and clinical implication of DNA methylation of obesity-related genes in acute myeloid leukemia (AML) has yet to be elucidated.

RESULTS

In the discovery stage, we identified that DNA methylation-associated LEP expression was correlated with prognosis among obesity-related genes from the databases of The Cancer Genome Atlas. In the validation stage, we verified that LEP hypermethylation was a frequent event in AML by both targeted bisulfite sequencing and real-time quantitative methylation-specific PCR. Moreover, LEP hypermethylation, correlated with reduced LEP expression, was found to be associated with higher bone marrow blasts, lower platelets, and lower complete remission (CR) rate in AML. Importantly, survival analysis showed that LEP hypermethylation was significantly associated with shorter overall survival (OS) in AML. Moreover, multivariate analysis disclosed that LEP hypermethylation was an independent risk factor affecting CR and OS among non-M3 AML. By clinical and bioinformatics analysis, LEP may be also regulated by miR-517a/b expression in AML.

CONCLUSIONS

Our findings indicated that the obesity-related gene LEP methylation is associated with LEP inactivation, and acts as an independent prognostic predictor in AML.

Rate of differentiation syndrome in patients based on timing of initial all-trans retinoic acid administration

All-trans-retinoic acid (ATRA) is the standard of care for the management of acute promyelocytic leukemia (APL), but can be associated with differentiation syndrome (DS). Over a seven-year period, we sought to determine the impact of ATRA initiation time on the development of DS. ATRA administration time had no impact on DS occurrence (p = =0.13), APL risk (p = =0.28) or regimen received (p = =0.1). Patients with higher mean body mass index (BMI) were more likely to develop moderate or severe DS (p = =0.02). Early treatment of APL is essential and maybe strongly considered in patients with elevated BMI.

Expression of leptin and leptin receptors in colorectal cancer-an immunohistochemical study

Obesity is demonstrated to be a risk factor in the development of cancers of various organs, such as colon, prostate, pancreas and so on. Leptine (LEP) is the most renowned of the adipokines. As a hormone, it mediates its effect through leptin receptor (LEPR), which is widely expressed in various tissues including colon mucosa. In this study, we have investigated the degree of expression of LEP and LEPR in colorectal cancer (CRC). We collected 44 surgically resected colon cancer tissues along with normal adjacent colon tissue (NACT) from a sample of CRC patients from the Malaysian population and looked for leptin and leptin receptors using immunohistochemistry (IHC). All the samples showed low presence of both LEP and LEPR in NACT, while both LEP and LEPR were present at high intensity in the cancerous tissues with 100% and 97.7% prevalence, respectively. Both were sparsed in the cytoplasm and were concentrated beneath the cell membrane. However, we did not find any significant correlation between their expression and pathological parameters like grade, tumor size, and lymph node involvement. Our study further emphasizes the possible causal role of LEP and LEPR with CRC, and also the prospect of using LEPR as a possible therapeutic target.

Anthropometric factors and risk of myeloid leukaemias and myelodysplastic syndromes: a prospective study and meta-analysis

There is insufficient evidence linking excess body weight to risk of myeloid malignancies. We investigated this association using data from the Cancer Prevention Study-II (CPS-II), and a meta-analysis of published cohort studies. Among 152 090 CPS-II participants, 387 acute myeloid leukaemias (AML), 100 chronic myeloid leukaemias (CML) and 170 MDS were identified over 21 years of follow-up. In CPS-II, body mass index (BMI) was weakly associated with risk of CML (hazard ratio [HR] = 1·04, 95% confidence interval [CI]: 0·99-1·09 per 1 unit increase in BMI), AML (HR = 1·01, 95% CI: 0·98-1·03) and MDS (HR = 1·03, 95% CI: 0·99-1·07). After controlling for other anthropometric factors, no clear association was observed for height, BMI at age 18 years or weight change. In the meta-analysis (n = 7117 myeloid leukaemias), BMI 25-29·9 kg/m² (HR_pooled  = 1·36, 95% CI: 1·12-1·59) and BMI ≥30 kg/m² (HR_pooled  = 1·43, 95% CI: 1·18-1·69) were associated with higher risk of myeloid leukaemia overall, compared to a BMI <25 kg/m² . Likewise, BMI ≥25 kg/m² was positively associated with both AML and CML risk individually in the meta-analysis. These results underscore the need for large studies to detect associations with rare cancers, and show a modest, but positive association between excess body weight and myeloid malignancy risk.

The role of adiponectin, LEPTIN, and ghrelin in the progress and prognosis of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Dysregulation of adipokine pathways is implicated in the carcinogenesis and ALL. The aim of this study is to present the most recent data available regarding the role of leptin, adiponectin and ghrelin in the pathogenesis and prognosis of ALL. The PubMed database was searched using 'Leptin', 'Adiponectin', 'Ghrelin', 'Cancer', 'Children' and 'Acute Lymphoblastic Leukemia' as keywords. The majority of the studies indicated that leptin levels are increased and adiponectin levels are decreased in ALL children at diagnosis, as well as in ALL survivors. Ghrelin levels were found to be lower at diagnosis and progressively increased during treatment. Further research is warranted, as the heterogeneity of the current studies, various treatment protocols and differences in sample sizes make it difficult to deduce solid conclusions regarding the role of adipokines in ALL.

Bone Marrow Fat and Hematopoiesis

Bone marrow fat cells comprise the largest population of cells in the bone marrow cavity, a characteristic that has attracted the attention of scholars from different disciplines. The perception that bone marrow adipocytes are "inert space fillers" has been broken, and currently, bone marrow fat is unanimously considered to be the third largest fat depot, after subcutaneous fat and visceral fat. Bone marrow fat (BMF) acts as a metabolically active organ and plays an active role in energy storage, endocrine function, bone metabolism, and the bone metastasis of tumors. Bone marrow adipocytes (BMAs), as a component of the bone marrow microenvironment, influence hematopoiesis through direct contact with cells and the secretion of adipocyte-derived factors. They also influence the progression of hematologic diseases such as leukemia, multiple myeloma, and aplastic anemia, and may be a novel target when exploring treatments for related diseases in the future. Based on currently available data, this review describes the role of BMF in hematopoiesis as well as in the development of hematologic diseases.

Leptin promotes apoptosis and inhibits autophagy of chondrocytes through upregulating lysyl oxidase-like 3 during osteoarthritis pathogenesis

OBJECTIVE

Leptin has been found highly expressed in human osteoarthritis. We aimed to explore the possible effects and mechanisms of leptin on the apoptosis and autophagy of chondrocytes during osteoarthritis pathogenesis.

METHODS

Gene expression profile from osteoarthritis affected and preserved cartilage were downloaded from NCBI's Gene Expression Omnibus database (GSE57218). Lysyl oxidase-like 3 (LOXL3) mRNA expression in cartilage tissues and leptin concentration in joint synovial fluid (SF) was measured in samples from 45 osteoarthritis patients and 25 healthy donors by real-time PCR and radioimmunoassay, respectively. Rat osteoarthritis model was induced by anterior cruciate ligament transection (ACLT). The expression of apoptosis regulators and autophagy markers were detected by Western blot. Cell survival and cell apoptosis were identified by CCK-8 and flow cytometry, respectively.

RESULTS

Re-analysis on GSE57218 indicated that LOXL3 mRNA was upregulated in osteoarthritis affected cartilage. LOXL3 mRNA was upregulated in osteoarthritis patients, which was positively correlated with SF leptin concentration. Similar results were obtained in rat osteoarthritis model. Moreover, ACLT surgery led to a significant increase in the protein levels of cleaved caspase 3, and a notable decrease in the protein levels of Bcl-2, LC3 II/LC3 I and Beclin1. Silencing of LOXL3 in ACLT and leptin treated primary chondrocytes significantly inhibited cell apoptosis, and promoted cell proliferation and autophagy. Moreover, overexpression of LOXL3 remarkably inhibited autophagy of chondrocytes via activating mTORC1.

CONCLUSIONS

LOXL3, a downstream of leptin, stimulated the apoptosis, but inhibited the autophagy of chondrocytes. LOXL3 is a potential therapy target for osteoarthritis.

A Ranking Approach for Probe Selection and Classification of Microarray Data with Artificial Neural Networks

Acute leukemia classification into its myeloid and lymphoblastic subtypes is usually accomplished according to the morphology of the tumor. Nevertheless, the subtypes may have similar histopathological appearance, making screening procedures difficult. In addition, approximately one-third of acute myeloid leukemias are characterized by aberrant cytoplasmic localization of nucleophosmin (NPMc(+)), where the majority has a normal karyotype. This work is based on two DNA microarray datasets, available publicly, to differentiate leukemia subtypes. The datasets were split into training and test sets, and feature selection methods were applied. Artificial neural network classifiers were developed to compare the feature selection methods. For the first dataset, 50 genes selected using the best classifier was able to classify all patients in the test set. For the second dataset, five genes yielded 97.5% accuracy in the test set.

Leptin Modulates Mitochondrial Function, Dynamics and Biogenesis in MCF-7 Cells

The adipokine leptin, known for its key role in the control of energy metabolism, has been shown to be involved in both normal and tumoral mammary growth. One of the hallmarks of cancer is an alteration of tumor metabolism since cancerous cells must rewire metabolism to satisfy the demands of growth and proliferation. Considering the sensibility of breast cancer cells to leptin, the objective of this study was to explore the effects of this adipokine on their metabolism. To this aim, we treated the MCF-7 breast cancer cell line with 50 ng/mL leptin and analyzed several features related to cellular and mitochondrial metabolism. As a result, leptin increased cell proliferation, shifted ATP production from glycolysis to mitochondria and decreased the levels of the glycolytic end-product lactate. We observed an improvement in ADP-dependent oxygen consumption and an amelioration of oxidative stress without changes in total mitochondrial mass or specific oxidative phosphorylation (OXPHOS) complexes. Furthermore, RT-PCR and western blot showed an up-regulation for genes and proteins related to biogenesis and mitochondrial dynamics. This expression signature, together with an increased mitophagy observed by confocal microscopy suggests that leptin may improve mitochondrial quality and function. Taken together, our results propose that leptin may improve bioenergetic efficiency by avoiding the production of reactive oxygen species (ROS) and conferring benefits for growth and survival of MCF-7 breast cancer cells.

Obesity over the life course and risk of acute myeloid leukemia and myelodysplastic syndromes

BACKGROUND

Overweight and obesity are known risk factors for a number of cancers, with recent evidence suggesting that risk of hematologic cancer is also increased in obese individuals. We evaluated associations between body mass index (BMI) at differing time points during the life course in population-based case control studies of acute myeloid leukemia (AML) and myelodysplatic syndromes (MDS).

METHODS

Cases were identified by the Minnesota Cancer Surveillance System. Controls were identified through the Minnesota State driver's license/identification card list. BMI was calculated using self-reported height and weight at ages 18, 35, and 50 years and two years prior to interview, and categorized as normal (18.5-25 kg/m(2)), overweight (25-29.9 kg/m(2)), obese class I (30-34.9 kg/m(2)), and obese class II/III (35+ kg/m(2)). All analyses were stratified by sex. Unconditional logistic regression was used to calculate odds ratios and 95% confidence intervals.

RESULTS

We included 420 AML cases, 265 MDS cases and 1388 controls. Obesity two years prior to diagnosis was associated with AML in both males and females (OR=2.22, 95% CI 1.28, 3.85 and OR=1.85, 95% CI 1.08, 3.15 for BMI≥35 vs. BMI 18.5-24.9, respectively). In contrast, associations between obesity and MDS were observed only in females. Weight change in adulthood was not consistently associated with either outcome.

CONCLUSION

Our results extend the emerging literature suggesting that obesity is a risk factor for hematologic malignancy and provide evidence that that the association remains regardless of timing of obesity. Obesity in adulthood is a modifiable risk factor for both MDS and AML.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Splice factor mutations and alternative splicing as drivers of hematopoietic malignancy

Differential splicing contributes to the vast complexity of mRNA transcripts and protein isoforms that are necessary for cellular homeostasis and response to developmental cues and external signals. The hematopoietic system provides an exquisite example of this. Recently, discovery of mutations in components of the spliceosome in various hematopoietic malignancies (HMs) has led to an explosion in knowledge of the role of splicing and splice factors in HMs and other cancers. A better understanding of the mechanisms by which alternative splicing and aberrant splicing contributes to the leukemogenic process will enable more efficacious targeted approaches to tackle these often difficult to treat diseases. The clinical implications are only just starting to be realized with novel drug targets and therapeutic strategies open to exploitation for patient benefit.

Role of leptin and leptin receptors in hematological malignancies

Leptin is an adipose-derived cytokine that has an important role in bodyweight homeostasis and energy balance. There are a number of studies which have suggested that leptin and its receptors dysregulation play a critical role in the development of malignancies including hematological malignancies, mainly via activation of the JAK/STAT pathway which regulates downstream signaling pathways such as PI3K/AKT signaling and ERK1/2. In this review, current understandings of leptin/leptin receptors mediated pathogenesis in various lymphoid malignancies are described. Blocking of the leptin receptor might be a unique therapeutic approach for many hematological malignancies.

Adiponectin is down-regulated in bone marrow interstitial fluid in hematological malignancy

Adipokines play a role in carcinogenesis in a variety of malignancies. These findings were established with regard to serum adipokines and malignancies. However, the expression of adipokines in bone marrow fluid remains unclear, and an investigation of the correlation between bone marrow adipokines and hematological malignancy is needed. The present study was designed to detect adipokine concentrations, including adiponectin, leptin and resistin, in bone marrow interstitial fluid from patients with hematological malignancy and controlled counterparts. The correlations between adipokines, body mass index, clinical parameters, and hematological malignancy were assessed. A total of 80 bone marrow samples were assessed for values of adipokines, adiponectin, leptin and resistin. Patients with hematological malignancy had lower levels of adiponectin. Adiponectin from leukemia bone marrow expressed significantly low values. The adiponectin levels were inversely correlated with body mass index. In conclusion, adiponectin was decreased in bone marrow from patients with leukemia and negatively correlated with body mass index.

All in the family: Clueing into the link between metabolic syndrome and hematologic malignancies

Metabolic syndrome constitutes a constellation of findings including central obesity, insulin resistance/type 2 diabetes mellitus (DM), dyslipidemia and hypertension. Metabolic syndrome affects 1 in 4 adults in the United States and is rapidly rising in prevalence, largely driven by the dramatic rise in obesity and insulin resistance/DM. Being central to the development of metabolic syndrome and its other related diseases, much focus has been placed on identifying the mitogenic effects of obesity and insulin resistance/DM as mechanistic clues of the link between metabolic syndrome and cancer. Pertinent mechanisms identified include altered lipid signaling, adipokine and inflammatory cytokine effects, and activation of PI3K/Akt/mTOR and RAS/RAF/MAPK/ERK pathways via dysregulated insulin/insulin-like growth factor-1 (IGF-1) signaling. Through variable activation of these multiple pathways, obesity and insulin resistance/DM pre-dispose to hematologic malignancies, imposing the aggressive and chemo-resistant phenotypes typically seen in cancer patients with underlying metabolic syndrome. Growing understanding of these pathways has identified druggable cancer targets, rationalizing the development and testing of agents like PI3K inhibitor idelalisib, mTOR inhibitors everolimus and temsirolimus, and IGF-1 receptor inhibitor linsitinib. It has also led to exploration of obesity and diabetes-directed therapies including statins and oral hypoglycemic for the management of metabolic syndrome-related hematologic neoplasms.

Deficient leptin signaling ameliorates systemic lupus erythematosus lesions in MRL/Mp-Fas lpr mice

Leptin is secreted by adipocytes, the placenta, and the stomach. It not only controls appetite through leptin receptors in the hypothalamus, it also regulates immunity. In the current study, we produced leptin-deficient MRL/Mp-Fas(lpr) mice to investigate the potential role of leptin in autoimmunity. C57BL/6J-ob/ob mice were backcrossed with MRL/Mp-Fas(lpr) mice, which develop human systemic lupus erythematosus (SLE)-like lesions. The effects of leptin deficiency on various SLE-like manifestations were investigated in MRL/Mp-Fas(lpr) mice. The regulatory T cell population in the spleen was analyzed by flow cytometry, and the effects of leptin on regulatory T cells and Th17 cells were evaluated in vitro. Compared with leptin-producing MRL/Mp-Fas(lpr) mice, leptin-deficient MRL/Mp-Fas(lpr) mice showed less marked splenomegaly and a particularly low population of CD3(+)CD4(-)CD8(-)B220(+) T cells (lpr cells). Their serum concentrations of Abs to dsDNA were lower, and renal histological changes at age 20 wk were ameliorated. Regulatory T cells were increased in the spleens of leptin-deficient MRL/Mp-Fas(lpr) mice. Leptin suppressed regulatory T cells and enhanced Th17 cells in vitro. In conclusion, blockade of leptin signaling may be of therapeutic benefit in patients with SLE and other autoimmune diseases.

The role of adipose tissue and obesity in causing treatment resistance of acute lymphoblastic leukemia

Obesity is responsible for ~90,000 cancer deaths/year, increasing cancer incidence and impairing its treatment. Obesity has also been shown to impact hematological malignancies, through as yet unknown mechanisms. Adipocytes are present in bone marrow and the microenvironments of many types of cancer, and have been found to promote cancer cell survival. In this review, we explore several ways in which obesity might cause leukemia treatment resistance. Obese patients may be at a treatment disadvantage due to altered pharmacokinetics of chemotherapy and dosage "capping" based on ideal body weight. The adipose tissue provides fuel to cancer cells in the form of amino acids and free fatty acids. Adipocytes have been shown to cause cancer cells to resist chemotherapy-induced apoptosis. In addition, obese adipose tissue is phenotypically altered, producing a milieu of pro-inflammatory adipokines and cytokines, some of which have been linked to cancer progression. Given the prevalence of obesity, understanding its role and adipose tissue in acute lymphoblastic leukemia treatment is necessary for evaluating current treatment regimen and revealing new therapeutic targets.

Higher fetuin-A, lower adiponectin and free leptin levels mediate effects of excess body weight on insulin resistance and risk for myelodysplastic syndrome

OBJECTIVE

Excess body weight has been implicated in the pathogenesis of myelodysplastic syndrome (MDS). We thus explored the role of serum fetuin-A reflecting ectopic hepatic fat deposition when storage capacity of adipocytes has been exceeded, free leptin reflecting overall fat mass and adiponectin reflecting visceral fat mass, all potential mediators of the effects of obesity on insulin resistance and, consequently, to MDS risk.

MATERIALS & METHODS

In a hospital-based case-control study, we studied 101 cases with incident, histologically confirmed primary MDS and 101 controls matched on gender, age and date of diagnosis, between 2004 and 2007. Serum fetuin-A, adiponectin, leptin, leptin receptor, free leptin and insulin were determined.

RESULTS

Higher serum fetuin-A, lower adiponectin and lower free leptin were all individually and independently associated with higher risk of MDS before and after controlling for matching and risk factors, such as age, gender, date of diagnosis, body mass index (BMI), family history of lymphohematopoietic cancer, smoking history and serum insulin. Interestingly, we have shown that these associations were prominent among overweight/obese individuals and persisted after controlling for BMI and serum insulin indicating that their effects are above and beyond insulinemia only.

CONCLUSION

Elevated serum fetuin-A but lower adiponectin and free leptin are associated with higher risk of MDS particularly among overweight/obese individuals. These findings suggest that the association between excessive weight gain and the risk of MDS could be mediated by fetuin-A, adiponectin and free leptin, which may have potential clinical and preventive implications.

Leptin, resistin and visfatin: the missing link between endocrine metabolic disorders and immunity

Adipose tissue is still regarded as a principle site for lipid storage and mobilizing tissue with an important role in the control of energy homeostasis. Additionally, adipose tissue-secreted hormones such as leptin, visfatin, resistin, apelin, omentin, sex steroids, and various growth factors are now regarded as a functional part of the endocrine system. These hormones also play an important role in the immune system. Several in vitro and in vivo studies have suggested the complex role of adipocyte-derived hormones in immune system and inflammation. Adipokines mediate beneficial and detrimental effects in immunity and inflammation. Many of these adipocytokines have a physiological role in metabolism. The uncontrolled secretions of several adipocytokines were associated with the stimulation of inflammatory processes leading to metabolic disorders including obesity, atherosclerosis, insulin resistance and type 2 diabetes. Obesity leads to the dysfunction of adipocytes andcorrelated with the imbalance of adipokines levels. In obese and diabetic conditions, leptin deficiency inhibited the Jak/Stat3/PI3K and insulin pathways. In this review, ample evidence exists to support the recognition of the adipocyte’s role in various tissues and pathologies. New integral insights may add dimensions to translate any potential agents into the future clinical armamentarium of chronic endocrine metabolic and inflammatory diseases. Functional balance of both adipocytes and immune cells is important to exert their effects on endocrine metabolic disorders; furthermore, adipose tissue should be renamed not only as a functional part of the endocrine system but also as a new part of the immune system.

Metabolism-related cytokine and hormone levels in the serum of patients with myelodysplastic syndromes

BACKGROUND

A number of cytokines secreted from the bone marrow stromal cells and circulating hormones related to bone, adipose tissue and glucose metabolism might be involved in the pathogenesis of myelodysplastic syndromes (MDS).

METHODS

Serum levels of cytokines related to the metabolism of bone tissue [osteocalcin and parathyroid hormone (PTH)], adipose tissue (adiponectin, leptin and ghrelin) and glucose [insulin and insulin-like growth factor-1 (IGF-1)] were determined in 72 patients suffering from MDS, mostly of the low-risk group according to FAB classification, and 41 healthy individuals (controls).

RESULTS

Adiponectin and osteocalcin serum levels were significantly elevated in the MDS patients. Leptin, insulin and IGF-1 serum levels were reduced. No difference was found in the serum levels of PTH and ghrelin. Leptin levels were reversibly associated with patient blast count.

CONCLUSION

Increased serum levels of adiponectin and low levels of IGF-1 in MDS patients may counterbalance the increased rate of apoptosis in the pool of hematopoietic progenitors. Osteocalcin secreted by osteoblasts regulates the renewal and proliferation of hematopoietic stem cells. Hormones and cytokines either secreted by the cells of the bone marrow stroma or transferred by the microcirculation act on hematopoietic progenitors and may regulate their differentiation, apoptosis and proliferation rate in MDS.

Impact of serum adiponectin and leptin levels in acute leukemia

Adipocytokines was stated to exert biological effect on tumor cells. Two adipokines, leptin and adiponectin in particular, have come to be recognized for their influence on tumor biology including leukemia. The prognostic effect of leptin and adiponectin concentrations in acute leukemia patients remains to be identified. This study was conducted on 80 acute leukemia patients: 35 acute myeloid leukemia (AML), 45 acute lymphoid leukemia (ALL), and 20 controls of matched age and sex. Leptin and adiponectin were assayed by enzyme-linked immunosorbent assay at diagnosis. Serum leptin levels were significantly higher in ALL patients, and significantly lower in AML patients when compared with normal controls (P = 0.01, P = 0.04 respectively). On the other hand, serum adiponectin levels were significantly lower in AML and ALL patients as compared with normal controls (P = 0.00 for both). No significant differences exist regarding body mass index between acute leukemia patients and normal controls (P > 0.05). Correlation studies revealed that there were significant negative correlations between serum adiponectin levels and bone marrow (BM) blast cells and serum lactic dehydrogenase (sLDH) in acute leukemia groups (r 0.542, P < 0.01, r 0.699, P < 0.001, respectively). Regarding serum leptin levels there were positive significant correlations with BM blast cells (r 0.74, P < 0.01), total WBC counts (r = 0.59, P < 0.05), sLDH (r 0.738, P < 0.01) in ALL group; and significant negative correlations with BM blast cells (r 0.542, P < 0.01) and sLDH in the AML group. Adipocytokines may represent a new non-invasive biomarker in acute leukemia patients. Estimation of adiponectin and leptin serum levels at acute leukemia diagnosis could also be considered as a prognostic marker, which will be used in acute leukemia stratification.

Leptin receptor in childhood acute leukemias

Ob-R receptor is encoded by db gene and belongs to class I cytokine receptors family. Its expression was observed in hematopoietic CD34+ stem cells, erythropoietic, myeloid and lymphoblastic lineages cell lines and in human leukemic blast cells in lymphomas, acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic myeloid leukemia (CML). The studies on human bone marrow cells show that JAK/STAT pathway plays a substantial role in signal transduction in young bone marrow cells. The aim of the study was to examine the relationship between leptin receptor expression and the proliferation of neoplastic hematopoietic cells in bone marrow. The study was performed in a total of 57 children of both sexes aged 3 months to 16 years. A group of 46 patients with acute leukemia involved 25 children with ALLB, 11 children with ALLT and 10 children with ANNL. The control group consisted of 11 non-obese children with non-malignant hematological disturbances. The tests were performed on bone marrow samples. The assessments of membrane expression of Ob-R and the antigens determining the phenotype of bone marrow cells were performed using a flow cytometry method. In acute lymphoblastic leukemia, a significant decrease of Ob-R expression on leukemic blasts was observed in comparison with respective populations of normal bone marrow cells. Also in progenitor cells populations a significant decrease of CD34+Ob-R+w ALLT and ALLB was observed in comparison with the cells from normal bone marrow. No statistically significant differences in the percentage of Ob-R+ cells in ANNL bone marrow and in control bone marrow were observed.

Trimming the fat: obesity and hematopoietic cell transplantation

Obesity, increasing worldwide, is common in patients undergoing hematopoietic cell transplantation (HCT). This complex physiological state may alter the outcome of cancer therapies by many mechanisms including direct effects on pathogenesis, host responses to disease and altered pharmacology of chemotherapy. Obesity has been associated with multiple adverse health outcomes. Reports of obese patients undergoing HCT are challenging to interpret because of the heterogeneity of obesity definitions, underlying diseases, graft sources and chemotherapy regimens employed. Compared with normal-weight patients, it appears that obese patients undergoing allogeneic HCT have a higher risk of non-relapse mortality and inferior survival whereas those receiving autologous HCT appear to have equivalent outcomes. These findings are also difficult to interpret because there is no consistent standard for calculating chemotherapy dose in this group and future studies on specific regimens in this population are urgently needed. Patients who have undergone bariatric surgery may be at risk for unexpected events because of impaired nutritional state and altered pharmacokinetics of oral drugs. We recommend that future studies utilize more consistent and biologically relevant definitions of obesity and that the pharmacokinetics and pharmacodynamics of specific conditioning regimens be studied. Until more evidence is available, a rationale is presented for dosing based on adjusted body weight. Moreover, recommendations are provided to guide future research efforts based on more definitive measurements of body fat and its distribution available through modern quantitative imaging techniques using dual energy X-ray absorptiometry or magnetic resonance imaging scanning.

The balance between leptin and adiponectin in the control of carcinogenesis - focus on mammary tumorigenesis

A number of studies indicate that a growing list of cancers may be influenced by obesity. In obese individuals these cancers can be more frequent and more aggressive resulting in reduced survival. One of the most prominent and well characterized cancers in this regard is breast cancer. Obesity plays a complex role in breast cancer and is associated with increased inflammation, angiogenesis and alterations in serum levels of potential growth factors such as insulin, adiponectin, leptin and estrogen. Reduced levels of serum adiponectin have been reported in breast cancer patients compared to healthy controls, particularly in postmenopausal women and the level of adiponectin has been shown to be inversely associated with insulin resistance. The role of serum leptin levels in breast cancer appears to be more complex. Some studies have shown leptin to be increased in women with breast cancer but other studies have found leptin to be decreased or unchanged. This may be due to a number of confounding issues. We and others propose that it may be the levels of adiponectin and leptin as well as the balance of adiponectin and leptin that are the critical factors in breast and other obesity related cancer tumorigenesis. This review will focus on the current understanding of the interplay between obesity and the functions of leptin and adiponectin. It will then examine what is known about their potential roles in cancer particularly as pertains to breast cancer and how the ratio of adiponectin to leptin may play a role in tumorigenesis.

Investigation of the component of Lycopodium serratum extract that inhibits proliferation and mediates apoptosis of human HL-60 leukemia cells

In this study, we investigate a plant commonly used in herbal medicines, Lycopodium serratum, which is believed to have anti-cancer properties. An alcoholic extract of L. serratum (LSE) was investigated for its ability to induce apoptosis in cultured human promyelocytic leukemia HL-60 cells. Treatment of HL-60 cells with various concentrations of LSE (6-100 μg/mL) resulted in a sequence of events characteristic of apoptosis, including loss of cell viability, morphological changes, and increased sub-G(1) DNA content. Serratenediol (SE), a known biologically active agent, was isolated from MC fraction of LSE and was able to demonstrate significant and dose-dependent growth inhibitory effects on HL-60 cells. Similar to the effects observed with the crude LSE, the SE-related effects included the formation of apoptotic bodies and fragmented DNA, as well as the accumulation of DNA in the sub-G(1) phase of the cell cycle. Analysis of the mechanism of these events indicated that SE treated cells had an increased ratio of Bax/Bcl-xL, released the cytochrome c, activated caspase-9, -3, and cleaved poly-ADP-ribose polymerase (PARP); these observations are hallmarks of apoptotic events. Thus, the results suggest that SE can induce apoptosis via regulating the ratio of Bax/Bcl-xL in HL-60 cell lines.

Prevention of fasting-mediated bone marrow atrophy by leptin administration

Leptin is an adipokine that regulates body weight. In the current study, we demonstrate that continuous injection of leptin prevents the lymphocyte reduction observed in fasted mice, especially the immature B cell populations in the bone marrow. Although leptin administration reduced apoptotic cells in the bone marrow of fasted mice, it did not prevent glucocorticoid-mediated apoptosis in vitro. Bone marrow atrophy has also been shown in the leptin receptor-deficient db/db mice. In order to investigate the mechanisms underlying these processes, we transplanted bone marrow cells from db/db or control (+m/+m) mice into C.B-17/lcr-scid/scid mice. We found that the spleen and bone marrow B cell populations were completely reconstituted when db/db and +m/+m cells were transplanted into scid mice. Our findings suggest that direct interactions between leptin and bone marrow cells are not essential for the development of B cells in a metabologically normal environment.

Leptin promoter G-2548A genotypes and associated serum leptin levels in childhood acute leukemia at diagnosis and under high-dose steroid therapy

Genotype/allele distributions of leptin promoter G-2548A polymorphism, serum leptin and insulin levels and body weight were not significantly different between 72 children (39 male/33 female; age range 1.08-16, median 6 years) with acute leukemia (56 acute lymphoblastic leukemia [ALL]/16 acute non-lymphoblastic leukemia [ANLL]) at diagnosis and 70 age- and sex-matched controls (p > 0.05). The - 2548GG genotype was associated with the highest leptin levels in controls and patients with acute leukemia after 7-day high-dose methylprednisolone (HDMP) therapy (p < 0.05), while no significant association of genotype with leptin levels was detected in patients at diagnosis (p > 0.05). One-week HDMP therapy in patients carrying the - 2548G allele caused a significant increase in leptin levels and body weight (p < 0.001), whereas increases in those carrying the - 2548AA genotype were insignificant (p > 0.05). Decreases in white blood cell counts of patients after therapy were insignificant in - 2548GG (p > 0.05) yet significant in - 2548GA and - 2548AA (p < 0.05) genotypes. These results revealed no association of leptin genotype with the etiology of childhood acute leukemia but a possible association with leptin levels and effects of HDMP therapy.

Therapy-related acute promyelocytic leukemia: observations relating to APL pathogenesis and therapy

Therapy-related acute promyelocytic leukemia (t-APL) is a well-recognized form of APL for which the underlying etiology has been well characterized. The pathogenesis of de novo (dn-APL) remains unknown; but epidemiologic studies have consistently identified increased body mass index (BMI), younger age, and ethnicity as possible risk factors. We analyzed demographics, clinical features, and treatment responses in a contemporary series of 64 patients treated with all-trans-retinoic acid and anthracycline-based therapy to assess for differences in these two etiologically distinct patient groups. Compared with patients with t-APL (n = 11), those with dn-APL (n = 53) had a greater median BMI (31.33 vs. 28.48), incidence of obesity (60.4% vs. 27.3%) (P = 0.04), and history of hyperlipidemia (45.3% vs. 18.2%) (P = 0.01). Fewer t-APL than dn-APL patients achieved complete remission at 63.6% vs. 92.5% respectively (P = 0.008). This was the result of a higher induction mortality rate of 36.4% vs. 7.5% respectively (P = 0.008). No cases of leukemic resistance were seen in either group. Overall survival (OS) was inferior in t-APL compared with dn-APL at 51% vs. 84%, respectively (P < 0.005), primarily as a result of higher induction mortality. Relapse occurred in nine patients (16.1%) overall, but no relapses occurred in the t-APL cohort. Our observations provide further support for the hypothesis that abnormalities in lipid homeostasis may in some way be of pathogenic importance in dn-APL. Therapy-related APL is sensitive to standard therapy with no cases of resistance or relapse seen. The inferior OS of the t-APL was due to induction mortality, possibly reflecting prior therapy.

Aberrant expressions of leptin and adiponectin receptor isoforms in chronic myeloid leukemia patients

BACKGROUND

Leptin and adiponectin receptors mediate the role of leptin in stimulating the growth of leukemic cells and the protective function of adiponectin undertaken in several malignancies such as leukemia. In this study, we investigated the involvement of the expression of leptin and adiponectin receptors in chronic myeloid leukemia (CML) pathogenesis.

METHODS

The expression of leptin receptor isoforms, OB-Rt, OB-Ra, and OB-Rb, and the expression of adiponectin receptors, AdipoR1 and AdipoR2, were measured as mRNA levels in two CML cell lines (K562 and Meg-01) and 20 CML patients and 24 healthy controls by using RT-PCR.

RESULTS

OB-Rt and OB-Ra isoforms expression of the leptin receptors were found to be significantly lower in Meg-01 cell lines than K562 cells. All leptin receptors were downregulated in CML patients and more particularly OB-Rb level was found to be undetectably low in normal PBMC as well as in CML patients. AdipoR1 expression level was higher in Meg-01 than in K562, whereas AdipoR2 level was found to be unchanged in both cell lines. Interestingly, while AdipoR1 expression increased in CML patients, AdipoR2 decreased. Moreover, imatinib therapy did not affect both leptin and adiponectin isoform expressions.

CONCLUSION

While the decrease in leptin receptor levels in CML patients was confirmed, the increase in AdipoR1 levels and relevant decrease in AdipoR2 levels depicted their possible involvement in CML pathogenesis. This suggests different functions of adiponectin receptors in CML development.

Increased BMI correlates with higher risk of disease relapse and differentiation syndrome in patients with acute promyelocytic leukemia treated with the AIDA protocols

We investigated whether body mass index (BMI) correlates with distinct outcomes in newly diagnosed acute promyelocytic leukemia (APL). The study population included 144 patients with newly diagnosed and genetically confirmed APL consecutively treated at a single institution. All patients received All-trans retinoic acid and idarubicin according to the GIMEMA protocols AIDA-0493 and AIDA-2000. Outcome estimates according to the BMI were carried out together with multivariable analysis for the risk of relapse and differentiation syndrome. Fifty-four (37.5%) were under/normal weight (BMI < 25), whereas 90 (62.5%) patients were overweight/obese (BMI ≥ 25). An increased BMI was associated with older age (P < .0001) and male sex (P = .02). BMI was the most powerful predictor of differentiation syndrome in multivariable analysis (odds ratio = 7.24; 95% CI, 1.50-34; P = .014). After a median follow-up of 6 years, the estimated cumulative incidence of relapse at 5 years was 31.6% (95% CI, 22.7%-43.8%) in overweight/obese and 11.2% (95% CI, 5.3%-23.8%) in underweight/normal weight patients (P = .029). Multivariable analysis showed that BMI was an independent predictor of relapse (hazard ratio = 2.45, 95% CI, 1.00-5.99, in overweight/obese vs under/normal weight patients, P = .049). An increased BMI at diagnosis is associated with a higher risk of developing differentiation syndrome and disease relapse in APL patients treated with AIDA protocols.

Treatment of acute promyelocytic leukemia with PETHEMA LPA 99 protocol: a Tunisian single center experience

Acute promyelocytic leukemia (APL) has now become the most curable of all subtypes of acute myeloid leukemia. A cure rate of 75-80% can be anticipated with a combination of all-trans retinoic acid (ATRA) and anthracyclines. In Tunisia, the ATRA era began in 1998 with the use, consecutively, of two regimens of a combination of ATRA with anthracycline and cytarabine (APL93), and without cytarabine (LPA99). From 2004, 39 patients with confirmed APL either by t(15;17) or PML/RARA were treated by the PETHEMA LPA 99 trial. The rationale of this protocol by avoiding cytarabine is to reduce death in complete remission (CR) without increasing the incidence of relapse. Thirty-three patients achieved CR (84.6%). The remaining six patients were considered as failure due to early death: three caused by differentiation syndrome (DS) and three died from central nervous system hemorrhage. Baseline blood cell count (WBC) >10 x 10(9)/l (P=0.26) and creatinine >1.4 mg/dl (P=0.42) were not predictive of mortality. DS was observed in 11 patients (30.5%) with a median onset time of 12 days (range: 3-23 days) and median WBC of 29 x 10(9)/L (range: 1.2 x 10(9)-82.7 x 10(9)/l). DS was severe in seven cases, moderate in four, and fatal in three cases. Body mass index > or =30 (P=0.044) and baseline WBC > or =20 x 10(9)/l (P=0.025) are independent predictors of DS. The median follow-up of this study is 36 months. Thirty patients are alive in continuous complete remission; two patients died in CR from septic shock and secondary myelodysplastic syndrome respectively; one patient died 47 months after achieving two relapses. Event free survival from diagnosis was 80% and overall survival was 82%. Our results are quite acceptable and can be improved by reducing mortality rate.

Leptin receptor expression and its association with PI3K/AKT signaling pathway in diffuse large B-cell lymphoma

We investigated the role of the leptin receptor (Ob-R) and its relationship with PI3K/AKT activation in diffuse large B-cell lymphoma (DLBCL) clinical samples followed by in vitro studies using a panel of CRC cell lines. Leptin exerts its physiological action through its receptor Ob-R. Overexpression of Ob-R has been implicated in the pathogenesis of a variety of malignancies; however, its role in DLBCL has not been investigated. Using immunohistochemistry on a large cohort of DLBCL samples in a tissue microarray format, Ob-R immunostaining was detected in 86/216 (39.8%). Ob-R overexpression was associated with the catalytic subunit p110 of PI3K (p = 0.0283), activated AKT (p = 0.0003), and antiapoptotic marker XIAP (p = 0.0008) expression. In in vitro analysis using DLBCL cell lines, our data showed that leptin stimulated cell proliferation and inhibited apoptosis via activation of the PI3K/AKT signaling pathway. Pretreatment of DLBCL cells with Ob-R specific small interference RNA or inactivation of PI3K/AKT activity by LY294002 abolished these responses. Altogether, these data suggest that leptin plays a critical role in DLBCL pathogesis through the P13K/AKT pathway via Ob-R.

B-cell chronic lymphocytic leukemia risk in association with serum leptin and adiponectin: a case-control study in Greece

AIM

Leptin and adiponectin are two well-studied adipokines in relation to malignancies. In this study, we examined the association between leptin/adiponectin and risk of B-cell chronic lymphocytic leukemia (B-CLL), as well as the relationships between adipokines and several established prognostic factors of B-CLL.

METHODS

Ninety-five patients with incident B-CLL and 95 hospital controls matched on age and gender were studied between 2001 and 2007, and blood samples were collected. Leptin, total and high molecular weight adiponectin, and prognostic markers of B-CLL were determined.

RESULTS

Cases had a higher body mass index (BMI) than controls (p = 0.01) and lower levels of leptin (p < 0.01). Significantly more cases than controls presented a family history of lymphohematopoietic cancer (LHC) (p = 0.01). Higher serum leptin levels were associated with lower risk of B-CLL adjusting for age, gender, family history of LHC, BMI and serum adiponectin; the multivariate odds ratio comparing highest to lowest tertile was 0.05 (95% CI 0.01-0.29, p trend < 0.001); Adiponectin was not significantly different between cases and controls.

CONCLUSION

Leptin was found to be inversely associated with risk of CLL but in contrast to prior studies of CLL and hematologic malignancies, this study found no significant association between CLL and adiponectin.

Adipocytokines in relation to Hodgkin lymphoma in children

This case-control study aims to explore the association of serum adiponectin/leptin with childhood Hodgkin lymphoma (HL). Study participants were 75 children with histologically confirmed HL, registered in the Nationwide Registry for Childhood Haematological Malignancies and 75 age- and gender-matched controls. Multiple conditional logistic regression analyses were performed, adjusting for sociodemographic and lifestyle parameters. Adiponectin levels were consistently higher among cases in all models with ORs >1.25; 95% CIs ranging from 0.9 to 1.8 and P-values from 0.09 to 0.20. By contrast, there was no association of serum leptin with HL. In conclusion, elevated serum adiponectin might be a risk factor for childhood HL.

High body mass index is an independent predictor of differentiation syndrome in patients with acute promyelocytic leukemia

Increased BMI has been correlated to an increased incidence of APL, but not to the occurrence of differentiation syndrome (DS) in APL. We consecutively treated 39 APL patients with ATRA and idarubicin (according to PETHEMA regimen). Median age was 26 years. Forty-one percent patients were classified as intermediate risk, and 59% as high risk according to Sanz's score. Thirty-three patients (85%) reached CR. Eleven of the 36 patients evaluable for DS (30.5%) developed this syndrome (severe in 7 cases, moderate in 4, and fatal in 3 cases) within a median of 12 days (range 3-23) of ATRA onset. Six of the 9 (66.6%) patients with BMI>or=30 developed DS vs. 5 of 27 (18.5%) with BMI<30 (p=0.012). Other predictors of DS in univariate analysis were: age>or=40 year (p=0.033), baseline WBC>or=20 x 10(9)/l (p=0.003), and creatinine>1.4 mg/dl (p=0.009). In multivariate analysis, BMI>or=30 remained an independent predictor of DS in addition to baseline WBC>or=20 x 10(9)/l.

Expression patterns of leptin receptor (OB-R) isoforms and direct in vitro effects of recombinant leptin on OB-R, leptin expression and cytokine secretion by human hematopoietic malignant cells

Several studies have implicated leptin in the pathophysiology of neoplasias. We investigated the direct effect of leptin on malignant hematopoietic tissue that included: primary acute myeloid leukemia (AML) cells, leukemic cell lines and bone marrow biopsies from multiple myeloma (MM) patients. PBMC, T-cells, B-cells and monocytes from healthy subjects served as controls. We defined the patterns of OB-R isoform expression in AML cells and leukemic cell lines in comparison to control cells by RT-PCR. rLeptin upregulated the expression of OB-R and endogenous leptin in AML blasts and certain cell lines but not in control cells. Cytometric Bead Array analysis of pro- and anti-inflammatory cytokines showed that rleptin upregulates IL-6 secretion by AML cells, various cytokines by the leukemic cell lines tested and IL-10 secretion by control PBMC, contributed by monocytes. Western immunoblotting revealed that the effect of rleptin was independent of JAK-2/phospho-JAK-2 protein levels. Finally, MM biopsies stained positive for leptin and, to a lesser extend, OB-R. Immunoreactivity was confined mostly to the nucleus of the myeloma cells. Normal myelocytes, promyelocytes and megakaryocytes stained weakly positive, and erythroid cells were constantly negative. We propose that the leptin/OB-R system is strongly and directly involved in supporting the growth of hematopoietic malignancies.

Abnormal adipokine levels and leptin-induced changes in gene expression profiles in multiple myeloma

BACKGROUND

Studies have revealed an association between overweight/obesity and multiple myeloma. However, the factors linking a dysregulated energy metabolism to this disease have not been identified. Adipose tissue produces and secretes the adipokines leptin, adiponectin and resistin, involved in metabolism and cell growth.

METHODS

We measured the plasma concentrations of these three adipokines in newly diagnosed multiple myeloma as well as in patients with relapse. We further explored the importance of leptin in multiple myeloma by performing gene expression profiling in two myeloma cell lines.

RESULTS

At diagnosis, leptin was increased (P < 0.05) in both female and male patients compared with controls. Adiponectin was reduced (P < 0.05) among male patients, whereas no significant changes in resistin were noted among any patients. In patients with relapse and treated with thalidomide, no particular adipokine pattern was revealed. Leptin induced the expression of several genes important for cell signaling, growth and viability.

CONCLUSIONS

The plasma concentrations of leptin and adiponectin, but not resistin, were abnormal in newly diagnosed multiple myeloma. Adipose tissue may modify the growth and metabolism of myeloma cells through adipokine-mediated effects.

Relationship between plasma leptin or soluble cleaved leptin-receptor concentrations and glucocorticoid sensitivity of peripheral blood mononuclear cells in patients with nephrotic syndrome

Leptin is a small peptide hormone which centrally regulates weight. Leptin receptor (OB-R) is expressed in hematopoietic cells, the central nervous, and immune systems. OB-R bears a homology similar to members of the class Iota cytokine family, and therefore, leptin appears to modulate immune responses. The aim of this study was to examine the effect of plasma leptin, soluble OB-R (sOB-R), and the free leptin index (FLI), the ratio between leptin and sOB-R levels, on the sensitivities of peripheral blood mononuclear cells (PBMCs) to prednisolone and cyclosporine in 16 healthy subjects and seven nephrotic syndrome (NS) patients. The NS patients had significantly higher serum sOB-R and lower FLI, compared with the healthy subjects (respectively, P=0.0026, P=0.0383). Whereas, the NS patients had significantly lower PBMC sensitivity to prednisolone (P=0.0049). PBMCs sensitivity to cyclosporine was not significantly different between the healthy subjects and the NS patients. In addition, when the data from all subjects were analyzed, there was a significantly positive correlation between plasma sOB-R concentrations and the IC50 values of prednisolone (P=0.0478). In contrast, plasma leptin concentrations and FLIs did not correlate significantly with the prednisolone and cyclosporine IC50 values. From these observations it can be suggested that plasma leptin has little effect on PBMC sensitivity to immunosuppressive drugs in NS patients. Molecular background(s) for the influence of sOB-R on the PBMC sensitivity to glucocorticoids remain(s) to be elucidated.

Predictive factors of all-trans-retinoic acid related complications during induction therapy for acute promyelocytic leukemia

BACKGROUND

The combination of all-trans-retinoic acid (ATRA) and chemotherapy has made acute promyelocytic leukemia (APL) a highly curable leukemia. However, several complications are reported with this treatment the most serious and life threatening being Retinoic Acid Syndrome (RAS). We aimed at identifying factors that could predict complications caused by ATRA during induction treatment of APL.

PATIENTS

Forty-two patients with confirmed APL (by t(15;17) and/or PML/RARA) treated at our institution (University hospital of Tunis) between January 1998 and June 2006 using two consecutive protocols: European APL93 trial (24 patients) until February 2004 and Spanish PETHEMA LPA99 trial (18 patients) more recently. Induction regimen consisted of ATRA 45 mg/m(2)/d until CR combined to DNR 60 mg/m(2)/d x 3+Cytarabine 200 mg/m(2)/d x 7 (APL93) and Idarubicin 12 mg/m(2) d2, 4, 6, 8 (LPA99). Prednisone (0.5 mg/kg d1-d15) was added if WBC >10 x 10(9)/L to prevent RAS in LPA 99.

RESULTS

Median age was 36 yr (7-64 yr), M/F=16/26 (0.61), median WBC was 2.4 x 10(9)/L (range 0.6-100 x 10(9)/L). WBC >10 x 10(9)/L was noted in 14 patients (33%). Additional cytogenetic abnormalities were seen in 12/42 (28%). Median body mass index (BMI=weight/height(2):N 20-25) was 24 kg/m(2) (range 16-40 kg/m(2)), BMI >30 was noted in nine patients (8F and 1M). Thirty-three patients achieved CR (78.57%):18/24 (75%) in APL93 versus 15/18 (83%) in LPA99. Nine patients (21.42%) had early death. Causes of early death were: RAS (6) and CNS hemorrhage (3). Complications due to ATRA were: RAS (10), Scrotal ulcerations (3), Sweet syndrome (2), Perineal ulcerations (1), and Pseudotumor cerebri (1). Prognostic factors for complications of ATRA (Fisher exact test) were: BMI >35 (p=0.055), induction treatment without cytarabine (LPA99 trial) (p=0.047), whereas age (p=0.74), gender (p=0.51), initial WBC (p=0.47), and additional cytogenetic abnormalities (p=0.83) were not predictive. Retinoic Acid Syndrome was more reported in patients with initial WBC >10 x 10(9)/L (p=0.08).

CONCLUSION

We found high BMI (>35) in female and treatment without Cytarabine to increase the risk of developing complications with ATRA.

Association of leptin -2548G/A and leptin receptor Q223R polymorphisms with increased risk for oral cancer

PURPOSE

We investigated the possible association of DNA polymorphisms -2548G/A and Q223R in the leptin (LEP) and leptin receptor (LEPR) genes, respectively, which both affect the amount of circulating cytokine-type hormone leptin, with risk for development of oral cancer.

METHODS

Polymerase chain reaction-based restriction analysis was performed in DNA samples of 150 patients with oral squamous cell carcinoma (OSCC) and 152 healthy control subjects of equivalent gender, age, and ethnicity (Greeks and Germans).

RESULTS

Compared to controls, the homozygous high gene expression genotype A/A of the LEP -2548G/A polymorphism was significantly increased in the subgroups of patients with advanced cancer stages (P = 0.0001; OR 9.0, 95% CI 2.62-30.89), with a positive family history of cancer (P = 0.0346; OR 3.55, 95% CI 1.15-11.01), without tobacco abuse (P = 0.0051; OR 9.69, 95% CI 1.03-91.24), and without alcohol abuse (P = 0.0472; OR 2.16, 95% CI 0.87-5.37). The homozygous low-leptin-binding genotype G/G of the LEPR Q223R polymorphism was strongly associated with an increased risk for OSCC for all patients (P = 0.0028; OR 4.11, 95% CI 1.30-12.97) as well for most of the patient subgroups.

CONCLUSIONS

The above findings are consistent with the growth-promoting role of leptin in cancer and its induction effect on angiogenesis and metastasis. This is the first study indicating the association of these LEP and LEPR gene polymorphisms with increased risk for OSCC.

Serum leptin level in acute myeloid leukemia patients

Leptin is a regulator of fat metabolism that is synthesized in adipocytes and released into circulation. The serum levels of leptin are, therefore, correlated with body fat mass and show a wide variation in healthy individuals. Leptin may have an additional indirect effect on leukemic hematopoesis. We investigated serum leptin levels with enzyme-linked immunosorbent assays in 14 acute myeloblastic leukemia (AML) patients before and after chemotherapy and compared the results with that of the levels determined 14 healthy controls. We found no significant difference between leptin levels before and after chemotherapy and control group. Therefore, serum leptin level should not be used as a diagnostic marker in acute leukemia patients. However, the possibility of regional leptin production by leukemia blasts in bone marrow stroma creates a high local concentration of leptin within bone marrow microenvironment and systemic leptin level in combination with local leptin production may affect leukemic hematopoesis.

Effects of high-fat diet and/or body weight on mammary tumor leptin and apoptosis signaling pathways in MMTV-TGF-alpha mice

INTRODUCTION

Obesity is a risk factor for postmenopausal breast cancer and is associated with shortened mammary tumor (MT) latency in MMTV-TGF-alpha mice with dietary-induced obesity. One link between obesity and breast cancer is the adipokine, leptin. Here, the focus is on diet-induced obesity and MT and mammary fat pad (MFP) leptin and apoptotic signaling proteins.

METHODS

MMTV-TGF-alpha mice were fed low-fat or high-fat diets from 10 to 85 weeks of age. High-Fat mice were divided into Obesity-Prone and Obesity-Resistant groups based on final body weights. Mice were followed to assess MT development and obtain serum, MFP, and MT.

RESULTS

Incidence of palpable MTs was significantly different: Obesity-Prone > Obesity-Resistant > Low-Fat. Serum leptin was significantly higher in Obesity-Prone compared with Obesity-Resistant and Low-Fat mice. Low-Fat mice had higher MFP and MT ObRb (leptin receptor) protein and Jak2 (Janus kinase 2) protein and mRNA levels in comparison with High-Fat mice regardless of body weight. Leptin (mRNA) and pSTAT3 (phosphorylated signal transducer and activator of transcription 3) (mRNA and protein) also were higher in MTs from Low-Fat versus High-Fat mice. Expression of MT and MFP pro-apoptotic proteins was higher in Low-Fat versus High-Fat mice.

CONCLUSION

These results confirm a connection between body weight and MT development and between body weight and serum leptin levels. However, diet impacts MT and MFP leptin and apoptosis signaling proteins independently of body weight.

Correlation between expression of leptin and clinicopathological features and prognosis in patients with gastric cancer

BACKGROUND

The relationship between the expression of leptin in the tissue of gastric cancer and the clinicopathological features as well as patients' outcome were investigated.

METHODS

Sixty-one gastric cancer specimens were investigated by immunohistochemical studies with anti-leptin and anti-vascular endothelial growth factor (VEGF) antibodies and by monitoring patients for at least 3 years after surgery.

RESULTS

A positive rate of leptin expression was significantly associated with Borrmann classification (Borrmann type 1 and type 2 68.2% vs Borrmann type 3 and type 4 or unclassified 35.3%), tumor histology (well differentiated tumors 87.5% vs poorly differentiated tumors 48.9%), lymph node metastasis (with 69.0% vs without 36.8%) and stage (stage III + IV 69.0% vs stage I + II 36.8%). There was a significant association between leptin expression and VEGF expression. In the poorly differentiated group, the overall survival rate for patients with a weak expression of leptin (histochemistry score <0.5) was significantly higher than that in patients with a strong expression (histochemistry score =0.5). The Cox proportional hazards model identified serosal involvement, tumor size, metastasis, tumor histology, leptin expression, lymph node metastasis, age and postoperative chemotherapy as significant prognostic factors.

CONCLUSIONS

The expression of leptin in the tissue of gastric cancer was significantly associated with tumor histology, Borrmann classification, lymph node metastasis and stage of gastric cancer. In patients with poorly differentiated gastric cancer, a poor prognosis was found in those with a strong expression of leptin.