Effects of leptin and leptin receptor gene polymorphisms on lung cancer

Association of leptin receptor polymorphisms with susceptibility of non-small cell lung cancer: Evidence from 2249 subjects

Non-small cell lung cancer (NSCLC) is increasing dramatically. It is believed that energy metabolism-related genes could play an important role in etiology of NSCLC. In this study, we sought to assess the correlation between three LEPR single nucleotide polymorphisms (rs1137101, rs1137100 and rs6588147) with NSCLS susceptibility. In total, 1193 NSCLC cases and 1056 controls were included. SNPscan™ genotyping method was used to analyze the genotypes of LEPR polymorphisms. Compared to rs6588147 GG in LEPR gene, this study identified a protective role of LEPR rs6588147 GA and GA/AA for the occurrence of NSCLC (GA vs. GG [p = 0.021] and GA/AA vs. GG [p = 0.030]). As well, we found that a protective role of LEPR rs6588147 for the occurrence of non-SCC subgroup (p < 0.05). By logistic regression analysis, we found that the rs6588147 A allele related genotypes might play a protective role for the occurrence of NSCLC in drinking, BMI ≥24 kg/m2, smoking and male subgroups. We also found that the rs1137101 A allele related genotypes played a protective role for the occurrence of NSCLC in male, younger participants (under 59 years) and overweight/obesity (BMI ≥24 kg/m2) subgroups. We found that LEPR Ars1037100Ars1037101Ars6588147 haplotype might play a protective role for the occurrence of NSCLC (p = 0.013). In addition, our findings indicated that LEPR rs1137100 G>A SNP might increase the risk of lymph node metastases (p = 0.038). This study highlights that LEPR rs6588147, rs1137101 genotypes and LEPR Ars1037100Ars1037101Ars6588147 haplotype are correlated with the occurrence of NSCLC. LEPR rs1137100 G>A SNP increases the risk of lymph node metastases.

Abnormal Phenylalanine Metabolism of Procapra przewalskii in Chronic Selenosis in Selenium-Enriched Habitats

Selenium (Se)-enriched habitats have led to chronic selenosis, seriously affecting the health and survival of Procapra przewalskii (P. przewalskii). Our targets were to explore the molecular mechanisms of chronic selenosis and to look for a new way to protect endangered species. The mineral contents of soils, grass, blood, and muscle were analyzed. The biochemical indices, antioxidant capability, and immune function were also investigated. The analyses of proteomics and metabolomics were also carried out. The results showed that the Se contents in the muscle and blood of P. przewalskii, and the soil and grass in the Se-enriched habitats were significantly higher than those in healthy pastures. The P. przewalskii in the Se-enriched habitats showed symptoms of anemia, decreased antioxidant capability, and low immune function. A total of 44 differential proteins and 36 differential metabolites were screened by analyzing their proteomics and metabolomics. These differential proteins and metabolites were involved in glycolysis pathway, amino acid biosynthesis, carbon metabolism, phenylalanine metabolism, and energy metabolism. In particular, phenylalanine metabolism was the common pathway of proteomics and metabolomics, which was an important finding in studying the mechanism of chronic selenosis in animals. This study will help us to further understand the mechanism of chronic selenosis in P. przewalskii, and it provides a scientific basis for the protection of endangered species in Se-enriched habitats.

Differentially Expressed Genes Analysis in the Human Small Airway Epithelium of Healthy Smokers Shows Potential Risks of Disease Caused by Oxidative Stress and Inflammation and the Potentiality of Astaxanthin as an Anti-Inflammatory Agent

Cigarette smoke (CS) was known for its effect of increasing oxidative stress that could trigger tissue injury and endothelial dysfunction mediated by free radicals and reactive oxygen species (ROS). ROS itself is a key signaling molecule that plays a role in the development of inflammatory disorders. Nuclear factor erythroid2 related factor2 (Nrf2) is the main regulator of antioxidant cellular response to cell and tissue-destroying components caused by CS. Nrf2 protein that is significantly activated in the smokers' small airway epithelium is followed by a series of gene expression changes in the same cells. This study aims to observe differentially expressed genes (DEGs) in the human small airway epithelium of smokers compared to genes whose expression changes due to astaxanthin (AST) treatment, an antioxidant compound that can modulate Nrf2. Gene expression data that was stored in the GEO browser (GSE 11952) was analyzed using GEO2R to search for DEG among smokers and nonsmokers subject. DEG was further compared to those genes whose expression changes due to astaxanthin treatment (AST) that were obtained from the Comparative Toxicogenomics Database (CTD; https://ctdbase.org/). DEG (p < 0.05) analysis result shows that there are 23 genes whose expression regulation is reversed compared to gene expression due to AST treatment. The gene function annotations of the 23 DEGs showed the involvement of some of these genes in chemical and oxidative stress, reactive oxygen species (ROS), and apoptotic signaling pathways. All of the genes were involved/associated with chronic bronchitis, adenocarcinoma of the lung, non-small-cell lung carcinoma, carcinoma, small cell lung carcinoma, type 2 diabetes mellitus, emphysema, ischemic stroke, lung diseases, and inflammation. Thus, AST treatment for smokers could potentially decrease the development of ROS and oxidative stress that leads to inflammation and health risks associated with smoking.

Single-Nucleotide Polymorphisms in LEP and LEPR Associated With Breast Cancer Risk: Results From a Multicenter Case-Control Study in Chinese Females

Background

Leptin (LEP) plays a physiological role through its specific receptor (LEPR) and is involved in the occurrence and development of breast cancer. Our current study aimed at determining the influence of single-nucleotide polymorphisms (SNPs) in the genes coding for LEP and LEPR on breast cancer risk.

Methods

In the present study, 963 breast cancer cases and 953 controls were enrolled. Five SNPs of LEP and two of LEPR were chosen to evaluate the correlation of selected SNPs with breast cancer susceptibility among women in northern and eastern China. Analyses were further stratified by body mass index (BMI), waist–hip rate (WHR), estrogen receptor, and progesterone receptor status. The expression patterns of risk variant-associated genes were detected by expression quantitative trait locus (eQTL) analysis with eQTLGen and The Cancer Genome Atlas database.

Results

There were significant differences between breast cancer cases and control groups in the menopausal status and family history of breast cancer. Two SNPs (rs1137101 and rs4655555) of the LEPR gene decreased overall breast cancer risk, and other five SNPs showed no significant association with breast cancer risk. rs1137101 (GA vs. GG; adjusted OR = 0.719, 95% CI = 0.578–0.894, p = 0.003) and rs4655555 (TT vs. AA; adjusted OR = 0.574, 95% CI = 0.377–0.873, p = 0.009) significantly decreased breast cancer risk after Bonferroni correction for multiple testing. In subgroup analyses, the GA and GA + AA genotypes of LEPR rs1137101 associated with decreased breast cancer risk in the subgroup of BMI ≤ 24 kg/m² or WHR ≥ 0.85 after Bonferroni correction. Furthermore, we found that the expressions of rs4655555-associated gene LEPR and leptin receptor overlapping transcript (LEPROT) were upregulated in breast cancer tumor tissues compared with adjacent normal tissues, and a higher expression of LEPR in tumor tissues was correlated with poor prognosis of breast cancer patients using The Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) data.

Conclusion

Our study demonstrated that the polymorphisms rs1137101 and rs4655555 located in the LEPR gene decreased breast cancer risk in Chinese females, which might be a research-worthy bio-diagnostic marker and applied for early prediction and risk assessment of breast cancer.

Investigation of leptin receptor rs1137101 G>A polymorphism with cancer risk: evidence from 35936 subjects

Leptin receptor (LEPR) signaling may be involved in promoting angiogenesis and proliferation, inhibiting apoptosis and playing a vital role in the progression of carcinogenesis. A number of studies have focused on the association of LEPR rs1137101 variants with susceptibility of cancer, however, the observed results were controversial. We searched literature on the relationship of LEPR rs1137101 G>A polymorphism with cancer risk by using PubMed and Embase databases, covering all publications up to 14 October 2018. In total, 44 case–control studies with 35,936 subjects were included. After combining all eligible studies, we identified null relationship between LEPR gene rs1137101 G>A polymorphism and overall cancer risk [A vs. G: odds ratio (OR ) =  0.97, 95% confidence interval (CI ) =  0.89–1.06, P = 0.547; AA vs. GG: OR  =  0.93, 95% CI  =  0.78–1.13, P = 0.476; AA/GA vs. GG: OR  =  0.99, 95% CI  =  0.91–1.09, P= 0.890 and AA vs. GA/GG: OR  = 0.92, 95% CI  =  0.82–1.04, P= 0.198]. However, in a subgroup analysis, there was an increased susceptibility of oral and oropharyngeal cancer in AA vs. GA/GG genetic model (OR, 1.83; 95% CI, 1.01–3.33; P=0.048). Considering the limited participants were included, the findings might be underpowered. Sensitivity analysis identified that any independent study omitted did not materially influence the pooled ORs and CIs. The results of publication bias detection showed that there was no evidence of bias. In summary, this analysis indicates that no significant association of cancer risk was identified to be correlated with rs1137101 G>A variants, even in stratified analyses.

Leptin rs7799039 (G2548A) polymorphism is associated with cancer risk: a meta-analysis involving 25,799 subjects

Background: Leptin (LEP) is a human analogous form of the mouse obese gene and plays a critical role in energy expenditure as well as the progression of carcinogenesis. Many studies exploring the relationship between the LEP rs7799039 (G2548A) polymorphism and cancer risk have observed controversial results. To extensively evaluate this potential association, we conducted this meta-analysis.

Methods: All eligible studies published up to August 2018 on the relationship between the LEP rs7799039 G>A polymorphism and cancer risk were obtained by searching PubMed, EMBASE, and the China Biology Medicine databases. The association of LEP rs7799039 G>A polymorphism with cancer risk was evaluated by crude ORs together with their 95% CI's.

Results: Thirty-one case–control studies involving 25,799 subjects were included for meta-analysis. We identify a significant correlation with an overall cancer risk when these eligible case–control studies were pooled for analysis: for AA vs GG: an OR = 1.22, 95% CI = 1.01–1.48, P = 0.042 and for AA/GA vs GG: an OR = 1.16, 95% CI = 1.02–1.33, P = 0.026. A significant association was also detected in Asians, prostate cancer, other cancers, and hematopoietic malignancy subgroups. Sensitivity analysis was conducted by deleting an individual study in turn and calculation of the pooled ORs and CIs of the remainders. The results of sensitivity analyses indicated that no eligible study influenced the pooled ORs and CIs materially. Begg’s and Egger’s tests revealed that there was no evidence of publication bias.

Conclusion: In conclusion, our study suggests that the LEP rs7799039 G>A polymorphism might contribute to the development of cancer. In order to further verify or refute our findings, large and well-designed epidemiological studies are needed.

The Expression of Leptin and Its Receptor During Tumorigenesis of Diffuse Gliomas such as Astrocytoma and Oligodendroglioma- Grade II, III and IV (NOS)

Background: Leptin, an adipocytokine functions via the leptin receptor, OB-Rb that contains an intact intracellular domain and activates the JAK/STAT signalling cascade. It stimulates growth, migration and invasion of cancer cells in vitro potentiating angiogenesis. Recently, the involvement of leptin in tumor progression is being explored. Gliomas exhibit poor prognosis, low survival rates demanding for novel therapeutic regimens resulting in discovery of many potential biomarkers and pharmaceutical targets. We analysed the potential role of leptin and OB-Rb in carcinogenesis of malignant gliomas. Methods: Sixty fresh tissue samples of diffuse gliomas were collected after tumor excision. Real time PCR, immunohistochemical (IHC) analysis and western blot analysis were carried out to assess the expression of leptin and its receptor. Results: The present study demonstrates the expression of leptin and LepR and their involvement in tumor progression. Of the 60 cases, 57 cases (95%) and 53 cases (88.3%) showed amplification for leptin and OB-Rb respectively. The expression of these proteins were measured semi-quantitatively and correlated with degree of malignancy (p<0.05). The bands were visualised on western blot. Conclusion: Leptin may be valued as a pharmaceutical target and anti-leptin compounds could be developed as drugs in mono- or combined therapies for these tumors.

Leptin receptor gene (A/G) polymorphism rs1137101 and renal cell carcinoma

Leptin plays an important role in carcinogenesis as leptin/leptin receptor signaling promotes the angiogenesis, proliferation, and inhibits epithelial cell apoptosis. Variants in the leptin receptor gene have potential associations with renal cell carcinoma (RCC). We aimed to investigate association of rs1137101 (A/G) polymorphism at LEPR gene with risk of RCC and patients survival. 123 individuals were classified into group I: 73 RCC patients and group II: 50 healthy controls. Genotyping of the Gln223Arg (A/G) polymorphism rs1137101 at LEPR gene was analyzed using allelic discrimination assay by Real-Time PCR technique. GG genotype was the most frequent among RCC patients (67.1%), while AA genotype was the most frequent in controls (60%); (p < 0.001). By univariate cox regression: gene polymorphism (GG versus GA +AA), stage, histopathologic subtype, and grade were found to affect survival significantly; however, the multivariate analysis showed that only gene polymorphism (GG versus GA +AA) and tumor stage significantly affect survival. LEPR gene variants rs1137101 might be a candidate risk factor for RCC in Egypt. GG genotype is associated with more aggressive tumor behavior and shorter survival compared with GA & AA genotypes so, genotyping of Gln223Arg (A/G) rs1137101 could also predict RCC outcome.

Genetic polymorphisms of IL-23R (rs7517847) and LEP (rs7799039) among Egyptian patients with hepatocellular carcinoma

BACKGROUND

Genetic polymorphisms of IL-23 R (rs7517847) and LEP (rs7799039) have been stated to be associated with various types of human cancers. The purpose of this work is to test the association of these genetic polymorphisms with hepatocellular carcinoma (HCC) among Egyptian patients.

SUBJECTS AND METHODS

This study involved 150 unrelated Egyptian HCC patients in addition to 100 healthy controls from the same locality. DNA was genotyped for these genetic polymorphisms using the PCR-RFLP technique.

RESULTS

The frequency of the IL-23 R (rs7517847) G and LEP (rs7799039) G alleles were significantly higher among HCC patients compared to controls (p = .004 and .02). However, HCC patients with the IL-23 R GG and LEP GG genotypes showed no significant difference compared to others regarding their clinical and laboratory markers.

CONCLUSIONS

IL-23 R (rs7517847) and LEP (rs7799039) polymorphisms were associated with an increased risk but not affecting the clinical presentation of HCC among Egyptian patients.

Gender Differences in Adipocyte Metabolism and Liver Cancer Progression

Liver cancer is the third most common cancer type and the second leading cause of deaths in men. Large population studies have demonstrated remarkable gender disparities in the incidence and the cumulative risk of liver cancer. A number of emerging risk factors regarding metabolic alterations associated with obesity, diabetes and dyslipidemia have been ascribed to the progression of non-alcoholic fatty liver diseases (NAFLD) and ultimately liver cancer. The deregulation of fat metabolism derived from excessive insulin, glucose, and lipid promotes cancer-causing inflammatory signaling and oxidative stress, which eventually triggers the uncontrolled hepatocellular proliferation. This review presents the current standing on the gender differences in body fat compositions and their mechanistic linkage with the development of NAFLD-related liver cancer, with an emphasis on genetic, epigenetic and microRNA control. The potential roles of sex hormones in instructing adipocyte metabolic programs may help unravel the mechanisms underlying gender dimorphism in liver cancer and identify the metabolic targets for disease management.

Plasma Leptin Levels and Risk of Incident Cancer: Results from the Dallas Heart Study

Purpose

Leptin dysregulation has been postulated to affect cancer risk through its effects on obesity and inflammation. Epidemiological data evaluating this relationship are conflicting and studies in non-white cohorts is lacking. Therefore, we examined the association of leptin with the risk of incident cancer in the multiethnic Dallas Heart Study (DHS).

Methods

Participants enrolled in the DHS without prevalent cancer and with baseline leptin measurements were included. Incident cancer cases were identified through a systematic linkage of the DHS and the Texas Cancer Registry. Leptin was evaluated both as a continuous variable and in sex-specific quartiles. Multivariable Cox proportional hazards modeling was performed to examine the association between leptin levels with incident cancer after adjusting for age, sex, race, smoking status, alcohol use, family history of malignancy, body mass index (BMI), diabetes mellitus and C-reactive protein.

Results

Among 2,919 participants (median age 44 years; 54% women; 70% nonwhite; median BMI 29.4 kg/m²), 190 (6.5%) developed cancer after median follow- up of 12 years. Median leptin levels were 12.9 (interquartile range [IQR] 5.8–29.5) ng/ml in the incident cancer group vs. 12.3 (IQR 5.4–26.4) ng/ml those without an incident cancer (p = 0.34). Leptin was not associated with cancer incidence in multivariable analysis (unit standard deviation increase in log-transformed leptin, hazard ratio 0.95; 95% confidence interval, 0.77–1.16; p = 0.60). No association was observed in analyses stratified by sex, race/ethnicity, diabetes, or obesity status.

Conclusions

In this study of a predominantly minority population, no association between premorbid leptin levels and cancer incidence was demonstrated. Despite preclinical rationale and positive findings in other studies, this association may not replicate across all racial/ethnic populations.

The role of adiponectin in obesity-associated female-specific carcinogenesis

Adipose tissue is a highly vascularized endocrine organ, and its secretion profiles may vary with obesity. Adiponectin is secreted by adipocytes that make up adipose tissue. Worldwide, obesity has been designated a serious health problem among women and is associated with a variety of metabolic disorders and an increased risk of developing cancer of the cervix, ovaries, uterus (uterine/endometrial), and breast. In this review, the potential link between obesity and female-specific malignancies is comprehensively presented by discussing significant features of the intriguing and complex molecule, adiponectin, with a focus on recent findings highlighting its molecular mechanism of action in female-specific carcinogenesis.