Impact of serum adiponectin and leptin levels in acute leukemia

The role of adiposity, adipokines and polymorphisms of leptin and adiponectin in myelodysplastic syndromes

The aim of the present study was to investigate the relationship between leptin and adiponectin gene polymorphisms, circulating levels of leptin and adiponectin, adiposity and clinical markers in patients with myelodysplastic syndrome (MDS). This cross-sectional study was conducted with 102 adults and elderly MDS patients and 102 age- and sex-matched controls. Clinical characteristics, co-morbidities, anthropometric data, laboratory evaluation and genetic analysis (polymorphisms -2548G > A/rs7799039 of the LEP gene and +276G > T/rs1501299 of the ADIPOQ gene) were investigated. Serum leptin was higher and adiponectin lower in MDS when compared with controls. There was a significant positive correlation between serum leptin levels and BMI (r = 0·264, P = 0·025), waist circumference (r = 0·235, P = 0·047), body fat percentage (BF %) (r = 0·373, P = 0·001) and the fat mass index (FMI) (r = 0·371, P < 0·001). A lower mean adiponectin was found among patients with high BF %, higher visceral adiposity index and metabolic syndrome. A significant association was found between the AA genotype (mutant) of the LEP polymorphism rs7799039 and male sex and blast excess (≥ 5 %). In addition, a significant association was observed between the TT genotype (mutant) of the ADIPOQ rs1501299 polymorphism and Fe overload. These results demonstrate the importance of a comprehensive and systematic evaluation in patients with MDS in order to identify and control negative factors not related to the disease at an early stage.

Obesity and Leukemia: Biological Mechanisms, Perspectives, and Challenges

PURPOSE OF REVIEW

To examine the epidemiological data on obesity and leukemia; evaluate the effect of obesity on leukemia outcomes in childhood acute lymphoblastic leukemia (ALL) survivors; assess the potential mechanisms through which obesity may increase the risk of leukemia; and provide the effects of obesity management on leukemia. Preventive (diet, physical exercise, obesity pharmacotherapy, bariatric surgery) measures, repurposing drugs, candidate therapeutic agents targeting oncogenic pathways of obesity and insulin resistance in leukemia as well as challenges of the COVID-19 pandemic are also discussed.

RECENT FINDINGS

Obesity has been implicated in the development of 13 cancers, such as breast, endometrial, colon, renal, esophageal cancers, and multiple myeloma. Leukemia is estimated to account for approximately 2.5% and 3.1% of all new cancer incidence and mortality, respectively, while it represents the most frequent cancer in children younger than 5 years. Current evidence indicates that obesity may have an impact on the risk of leukemia. Increased birthweight may be associated with the development of childhood leukemia. Obesity is also associated with worse outcomes and increased mortality in leukemic patients. However, there are several limitations and challenges in meta-analyses and epidemiological studies. In addition, weight gain may occur in a substantial number of childhood ALL survivors while the majority of studies have documented an increased risk of relapse and mortality among patients with childhood ALL and obesity. The main pathophysiological pathways linking obesity to leukemia include bone marrow adipose tissue; hormones such as insulin and the insulin-like growth factor system as well as sex hormones; pro-inflammatory cytokines, such as IL-6 and TNF-α; adipocytokines, such as adiponectin, leptin, resistin, and visfatin; dyslipidemia and lipid signaling; chronic low-grade inflammation and oxidative stress; and other emerging mechanisms. Obesity represents a risk factor for leukemia, being among the only known risk factors that could be prevented or modified through weight loss, healthy diet, and physical exercise. Pharmacological interventions, repurposing drugs used for cardiometabolic comorbidities, and bariatric surgery may be recommended for leukemia and obesity-related cancer prevention.

Obesity, bone marrow adiposity, and leukemia: Time to act

Obesity has taken the face of a pandemic with less direct concern among the general population and scientific community. However, obesity is considered a low-grade systemic inflammation that impacts multiple organs. Chronic inflammation is also associated with different solid and blood cancers. In addition, emerging evidence demonstrates that individuals with obesity are at higher risk of developing blood cancers and have poorer clinical outcomes than individuals in a normal weight range. The bone marrow is critical for hematopoiesis, lymphopoiesis, and myelopoiesis. Therefore, it is vital to understand the mechanisms by which obesity-associated changes in BM adiposity impact leukemia development. BM adipocytes are critical to maintain homeostasis via different means, including immune regulation. However, obesity increases BM adiposity and creates a pro-inflammatory environment to upregulate clonal hematopoiesis and a leukemia-supportive environment. Obesity further alters lymphopoiesis and myelopoiesis via different mechanisms, which dysregulate myeloid and lymphoid immune cell functions mentioned in the text under different sequentially discussed sections. The altered immune cell function during obesity alters hematological malignancies and leukemia susceptibility. Therefore, obesity-induced altered BM adiposity, immune cell generation, and function impact an individual's predisposition and severity of leukemia, which should be considered a critical factor in leukemia patients.

Circulating Biomarkers Associated with the Diagnosis and Prognosis of B-Cell Progenitor Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a hematological disease characterized by the dysfunction of the hematopoietic system that leads to arrest at a specific stage of stem cells development, suppressing the average production of cellular hematologic components. BCP-ALL is a neoplasm of the B-cell lineage progenitor. BCP-ALL is caused and perpetuated by several mechanisms that provide the disease with its tumor potential and genetic and cytological characteristics. These pathological features are used for diagnosis and the prognostication of BCP-ALL. However, most of these paraclinical tools can only be obtained by bone marrow aspiration, which, as it is an invasive study, can delay the diagnosis and follow-up of the disease, in addition to the anesthetic risk it entails for pediatric patients. For this reason, it is crucial to find noninvasive and accessible ways to supply information concerning diagnosis, prognosis, and the monitoring of the disease, such as circulating biomarkers. In oncology, a biomarker is any measurable indicator that demonstrates the presence of malignancy, tumoral behavior, prognosis, or responses to treatments. This review summarizes circulating molecules associated with BCP-ALL with potential diagnostic value, classificatory capacity during monitoring specific clinic features of the disease, and/or capacity to identify each BCP-ALL stage regarding its evolution and outcome of the patients with BCP-ALL. In the same way, we provide and classify biomarkers that may be used in further studies focused on clinical approaches or therapeutic target identification for BCP-ALL.

LEP promoter methylation in the initiation and progression of clonal cytopenia of undetermined significance and myelodysplastic syndrome

BACKGROUND

Idiopathic non-clonal cytopenia (ICUS) and clonal cytopenia (CCUS) are common in the elderly population. While these entities have similar clinical presentations with peripheral blood cytopenia and less than 10% bone marrow dysplasia, their malignant potential is different and the biological relationship between these disorders and myeloid neoplasms such as myelodysplastic syndrome (MDS) is not fully understood. Aberrant DNA methylation has previously been described to play a vital role in MDS and acute myeloid leukemia (AML) pathogenesis. In addition, obesity confers a poorer prognosis in MDS with inferior overall survival and a higher rate of AML transformation. In this study, we measured DNA methylation of the promoter for the obesity-regulated gene LEP, encoding leptin, in hematopoietic cells from ICUS, CCUS and MDS patients and healthy controls. We investigated whether LEP promoter methylation is an early event in the development of myeloid neoplasms and whether it is associated with clinical outcome.

RESULTS

We found that blood cells of patients with ICUS, CCUS and MDS all have a significantly hypermethylated LEP promoter compared to healthy controls and that LEP hypermethylation is associated with anemia, increased bone marrow blast percentage, and lower plasma leptin levels. MDS patients with a high LEP promoter methylation have a higher risk of progression, shorter progression-free survival, and inferior overall survival. Furthermore, LEP promoter methylation was an independent risk factor for the progression of MDS in a multivariate Cox regression analysis.

CONCLUSION

In conclusion, hypermethylation of the LEP promoter is an early and frequent event in myeloid neoplasms and is associated with a worse prognosis.

Obesity and cancer: focus on leptin

Over the past decades, obesity has grown to epidemic proportions worldwide. It has been associated with an increased risk for different types of cancer. In addition, obesity has been associated with a poor prognosis, an increased risk of metastasis and mortality, and resistance to anti-cancer therapies. The pathophysiological mechanisms underlying the obesity-cancer connection have not yet been fully elucidated. However, this connection could result, at least in part, from the action of adipokines, whose levels are increased in obesity. Among these adipokines, evidence suggests leptin's critical role in linking obesity to cancer. In this review, we first summarize the current state of the literature regarding the implication of leptin in tumorigenic processes. Next, we focus on the effects of leptin on the anti-tumor immune response. Then, we discuss the influence of leptin on the efficiency of antineoplastic treatments and the development of tumor resistance. Finally, we highlight the use of leptin as a potential target for the prevention and treatment of cancer.

Maternal obesity and acute lymphoblastic leukemia risk in offspring: A summary of trends, epidemiological evidence, and possible biological mechanisms

Acute lymphoblastic leukemia, a heterogenous malignancy characterized by uncontrolled proliferation of lymphoid progenitors and generally initiated in utero, is the most common pediatric cancer. Although incidence of ALL has been steadily increasing in recent decades, no clear reason for this trend has been identified. Rising concurrently with ALL incidence, increasing maternal obesity rates may be partially contributing to increasing ALL prevelance. Epidemiological studies, including a recent meta-analysis, have found an association between maternal obesity and leukemogenesis in offspring, although mechanisms underlying this association remain unknown. Therefore, the purpose of this review is to propose possible mechanisms connecting maternal obesity to ALL risk in offspring, including changes to fetal/neonatal epigenetics, altered insulin-like growth factor profiles and insulin resistance, modified adipokine production and secretion, changes to immune cell populations, and impacts on birthweight and childhood obesity/adiposity. We describe how each proposed mechanism is biologically plausible due to their connection with maternal obesity, presence in neonatal and/or fetal tissue, observation in pediatric ALL patients at diagnosis, and association with leukemogenesis, A description of ALL and maternal obesity trends, a summary of epidemiological evidence, a discussion of the pathway from intrauterine environment to subsequent malignancy, and propositions for future directions are also presented.

Evaluation of Sestrin 2, Adiponectin, AMPK, and mTOR Genes Expression in Acute Myeloid Leukemia Patients

Background:

Effective treatment of acute myeloid leukemia (AML) is still controversial, therefore; a comprehensive understanding regarding the impaired cellular signaling pathways in AML can be useful in designing new therapeutic approaches. Among signaling pathways involved in AML, the mammalian target of rapamycin (mTOR) signaling pathway is of particular importance. While dysregulation of mTOR signaling has been reported in a wide range of patients with AML, but most studies have focused on mTOR downstream targets, and mTOR upstream targets have been overlooked.

Objective:

In this study, expression of mTOR genes and three upstream targets (5' adenosine monophosphate-activated protein kinase (AMPK, adiponectin, and sestrin 2) involved in mTOR signaling was investigated.

Materials and Methods:

In this study, expression of mTOR, AMPK, sestrin 2, and adiponectin genes in 60 patients with AML were evaluated compared to those of 30 healthy individuals as controls using the Real-Time polymerase chain reaction (Real-Time RT-PCR) method.

Results:

According to the results, there was a significant difference in the expression of all the studied genes in patients in comparison to the normal control group (P <0.05). Expression of the mTOR gene was increased, while expression of AMPK, sestrin 2, and adiponectin genes was decreased in the patients with AML. Mean expression of the genes (2-ΔCt) (AMPK, sestrin 2, adiponectin, and mTOR) was equal to 7.9, 3.2, 3.74, and 1.49 for controls and 6, 2.1, 2.83, and 2.64 for patients with AML, respectively.

Conclusions:

Given the decreased expression levels of sestrin 2, adiponectin, and AMPK genes as tumor inhibitors and the increased expression level of the mTOR gene as an oncogene in the patients with AML in our study, it is thought that disruption of this pathway may be involved in leukemogenesis and can be considered as an effective factor in the progression of cancer.

Abnormal bone marrow microenvironment: the “harbor” of acute lymphoblastic leukemia cells

Bone marrow (BM) microenvironment regulates and supports the production of blood cells which are necessary to maintain homeostasis. In analogy to normal hematopoiesis, leukemogenesis is originated from leukemic stem cells (LSCs) which gives rise to more differentiated malignant cells. Leukemia cells occupy BM niches and reconstruct them to support leukemogenesis. The abnormal BM niches are the main sanctuary of LSCs where they can evade chemotherapy-induced death and acquire drug resistance. In this review, we focus on the protective effects of BM niche cells on acute lymphoblastic leukemia cells.

The Impact of Obesity on the Outcomes of Adult Patients with Acute Lymphoblastic Leukemia - A Single Center Retrospective Study

Introduction

Obesity is a worldwide problem that is related to cardiac disease, thrombosis and cancer. However, little is known about the impact of obesity on the outcomes of adult acute lymphoblastic leukemia (ALL) patients.

Methods

We retrospectively evaluated a cohort of 154 newly diagnosed adult ALL patients between 1994 and 2011 at Mayo Clinic (Rochester). According to the World Health Organization (WHO) international BMI classification, patients were stratified as underweight, normal weight, overweight, and obese. For some analyses, patients were also stratified according to a two-sided non-obese or obese classification.

Results

The median follow-up time was 8.37 years. Obese patients were more likely to be women (p=0.024) and ≥60 years old (p=0.003). Five-year mortality rates were higher in obese patients than non-obese [HR 95% CI: 1.60 (1.03-2.50) p=0.035]. This was also the case in subgroup analysis among T-cell patients although the number of patients was small [HR 95% CI: 5.42 (1.84-15.98) p<0.001]. There was no difference in mortality among the B-cell patients. After adjusting for baseline variables, the difference in mortality remained in several models. There was no difference in EFS or cumulative incidence of relapse rates between obese and non-obese patients among the overall population.

Discussion

In conclusion, our study suggests that adult ALL patients with obesity have lower survival rates, especially in T-cell ALL.

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.

Is There A Causal Relationship between Childhood Obesity and Acute Lymphoblastic Leukemia? A Review

Childhood obesity is a growing epidemic with numerous global health implications. Over the past few years, novel insights have emerged about the contribution of adult obesity to cancer risk, but the evidence base is far more limited in children. While pediatric patients with acute lymphoblastic leukemia (ALL) are at risk of obesity, it is unclear if there are potential causal mechanisms by which obesity leads to ALL development. This review explores the endocrine, metabolic and immune dysregulation triggered by obesity and its potential role in pediatric ALL's genesis. We describe possible mechanisms, including adipose tissue attraction and protection of lymphoblasts, and their impact on ALL chemotherapies' pharmacokinetics. We also explore the potential contribution of cytokines, growth factors, natural killer cells and adipose stem cells to ALL initiation and propagation. While there are no current definite causal links between obesity and ALL, critical questions persist as to whether the adipose tissue microenvironment and endocrine actions can play a causal role in childhood ALL, and there is a need for more research to address these questions.

Adipokines in young survivors of childhood acute lymphocytic leukemia revisited: beyond fat mass

PURPOSE

This cross-sectional study evaluated the relationship between adipokines (leptin, adiponectin, visfatin, and resistin) and adiposity indexes regarding sex and cranial radiotherapy exposure among young acute lymphocytic leukemia survivors.

METHODS

A multivariate analysis of covariance (MANCOVA) was used to evaluate the joint effect of sex, cranial radiotherapy, and body mass index (BMI) z-score (model 1) or fat mass index (FMI) (model 2) on adipokines.

RESULTS

This study included 55 survivors of childhood acute lymphocytic leukemia between 15 and 23 years of age from both sexes (56.4% female); 43.6% of the sample had undergone cranial radiotherapy (18-24 Gy). The BMI z-score, the FMI, and sex (P<0.050 for all) influenced at least one adipokine, while cranial radiotherapy exposure was marginal in model 2. Parameter estimates from the MANCOVA's final model showed that the BMI z-score (β=-0.437, P=0.010) and the FMI (β=-0.209, P=0.004) negatively influenced adiponectin, while the FMI positively affected resistin (β=0.142, P=0.020). The relationship between leptin, visfatin, and the adiposity ndexes could not be established. In model 1, females presented with increased adiponectin (β=-1.014, P=0.011) and resistin (β=-1.067, P=0.002) levels; in model 2, female sex positively affected adiponectin (β=-1.515, P=0.001) and marginally influenced resistin (β=-0.707, P=0.054) levels. Cranial radiotherapy negatively determined visfatin levels in both final models (P<0.050).

CONCLUSION

Changes in body fat may be associated with adipose tissue dysfunction and should be carefully evaluated in survivors of acute lymphocytic leukemia, considering both sex and cranial radiotherapy exposure, to treat disorders that may possibly aggravate their risk for early cardiovascular disease.

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.

Circulating adiponectin levels in various malignancies: an updated meta-analysis of 107 studies

Early detection of cancers is challenging for lack of specific biomarkers. Adiponectin is an adipokine predominantly derived from adipocytes and hypoadiponectinemia has been reported to associate with risk of many types of cancers. However, available evidence is controversial. Some studies show that increased adiponectin levels correlate with cancer risk. Therefore, we performed a meta-analysis of the association between circulating adiponectin levels and cancer development. A systematic search of PubMed, EMBASE, Wiley Online Library and Cochrane Library was conducted for eligible studies involving circulating adiponectin and malignancies from inception to August 8, 2015. Standard mean differences (SMDs) with 95% confidence intervals (95% CIs) were calculated by use of a random-effect model. Funnel plot and Egger's linear regression test were conducted to examine the risk of publication bias. 107 studies were included with 19,319 cases and 25,675 controls. The pooled analysis indicated that circulating adiponectin levels were lower in patients with various cancers than in controls, with a pooled SMD of −0.334 μg/ml (95% CI, −0.465 to −0.203, P = 0.000). No evidence of publication bias was observed. Circulating high molecular weight adiponectin levels were also lower in cancer patients than in controls, with a pooled SMD of −0.502 μg/ml (95% CI, −0.957 to −0.047, P = 0.000). This meta-analysis provides further evidence that decreased adiponectin levels is associated with risk of various cancers. Hypoadiponectinemia may represent a useful biomarker for early detection of cancers.

Evolving role of adiponectin in cancer-controversies and update

Adiponectin (APN), an adipokine produced by adipocytes, has been shown to have a critical role in the pathogenesis of obesity-associated malignancies. Through its receptor interactions, APN may exert its anti-carcinogenic effects including regulating cell survival, apoptosis and metastasis via a plethora of signalling pathways. Despite the strong evidence supporting this notion, some work may indicate otherwise. Our review addresses all controversies critically. On the whole, hypoadiponectinaemia is associated with increased risk of several malignancies and poor prognosis. In addition, various genetic polymorphisms may predispose individuals to increased risk of obesity-associated malignancies. We also provide an updated summary on therapeutic interventions to increase APN levels that are of key interest in this field. To date efforts to manipulate APN levels have been promising, but much work remains to be done.

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 as a biomarker linking obesity and adiposopathy to hematologic malignancies

Higher body mass index and adiposopathy have been associated with increased risk of hematologic malignancies such as leukemia, multiple myeloma, myeloproliferative disorders, Hodgkin’s and non-Hodgkin’s lymphoma, and myelodysplastic syndromes. Adiponectin is a multimeric protein of the white adipose tissue presenting anti-inflammatory, insulin-sensitizing, anti-atherogenic, cardioprotective, and anti-neoplastic properties. Its anti-neoplastic actions are manifested via two mechanisms: (i) direct action on tumor cells by enhancing receptor-mediated signaling pathways and (ii) indirect action by regulating inflammatory responses, influencing cancer angiogenesis, and modulating insulin sensitivity at the target tissue site. In the bone marrow milieu, adiponectin and its main receptors are expressed by the majority of bone marrow stromal cell populations influencing hematopoietic stem cells function. Adiponectin may represent a molecular mediator relating adiposopathy with leukemogenesis and myelomagenesis. Several epidemiological studies conducted to date relate hypoadiponectinemia to the risk of myeloid-derived hematopoietic cancer and multiple myeloma. Adiponectin may be a promising biomarker with potential diagnostic and prognostic utility in determining the likelihood of myeloma and leukemia progression in certain cohorts of monoclonal gammopathy of undetermined significance patients and in myeloid hematologic malignancies, respectively. This review summarizes experimental and epidemiologic data regarding the role of adiponectin in hematologic malignancies in the context of adiposopathy. Enhancement of endogenous adiponectin, adiponectin replacement, or manipulation of adiponectin receptor sensitivity may be an attractive goal for prevention and an effective therapeutic strategy against hematopoietic cancer, specifically in overweight/obese individuals. Further studies are required to elucidate the role of the bone marrow microenvironment adiponectin in complex interactions involved in preleukemic and leukemic states.