Chunhua Yang

Circulating interleukin-6 and cancer: A meta-analysis using Mendelian randomization

Interleukin-6 (IL-6) plays a contributory role in the progression and severity of many forms of cancer; it however remains unclear whether the relevance between circulating IL-6 and cancer is causal. We therefore meta-analyzed published articles in this regard using IL-6 gene -174G/C variant as an instrument. Seventy-eight and six articles were eligible for the association of -174G/C variant with cancer and circulating IL-6, respectively. Overall analyses failed to identify any significance between -174G/C and cancer risk. In Asians, carriers of the -174CC genotype had an 1.95-fold increased cancer risk compared with the -174GG genotype carriers (Pu2009=u20090.009). By cancer type, significance was only attained for liver cancer with the -174C allele conferring a reduced risk under allelic (odds ratio or ORu2009=u20090.74; Pu2009=u20090.001), homozygous genotypic (ORu2009=u20090.59; Pu2009=u20090.029) and dominant (ORu2009=u20090.67; Pu2009=u20090.004) models. Carriers of the -174CC genotype (weighted mean difference or WMDu2009=u2009−4.23u2009pg/mL; Pu2009<u20090.001) and -174C allele (WMDu2009=u2009−3.43u2009pg/mL; Pu2009<u20090.001) had circulating IL-6 reduced significantly compared with the non-carriers. In further Mendelian randomization analysis, a reduction of 1u2009pg/mL in circulating IL-6 was significantly associated with an 12% reduced risk of liver cancer. Long-term genetically-reduced circulating IL-6 might be causally associated with a lower risk of liver cancer.

Causal relevance of circulating high-density lipoprotein cholesterol with cancer: a Mendelian randomization meta-analysis

We summarized published data on the associations of apolipoprotein E (APOE) gene ε2/ε3/ε4 polymorphism with both cancer risk and circulating lipid profiles, aiming to examine the causal relevance between lipids and cancer risk. Article identification and data abstraction were conducted in duplicate and independently by two authors. Data were analyzed by STATA software. Twenty-five articles that examined the associations of APOE gene ε2/ε3/ε4 polymorphism with either cancer risk (n = 22) or circulating lipid changes (n = 4) were eligible. The presence of ε2 and ε4 alleles showed no overall associations with overall cancer risk when compared with ε3 allele. The ε4 allele was significantly associated with 1.40-fold (odds ratio or OR = 1.40; 95% confidence interval or CI: 1.00–1.94; P = 0.047) increased risk of developing cancer in Asian populations, and the presence of heterogeneity was low (I2 = 37.6%). Carriers of ε3/ε4 genotype had a significant reduction in circulating HDL-C (WMD = −2.62; 95% CI: −4.19 to −1.04; P = 0.001) without heterogeneity (I2 = 16.6%). The predicted odds of having cancer for 1u2005mg/dL reduction in circulating HDL-C was 1.14 (95% CI: 1.00 to 1.89). The findings of this Mendelian randomization meta-analysis demonstrate that reduced circulating HDL-C might be a potentially causal risk factor for the development of overall cancer in Asians.

Quantitative dot blot analysis (QDB), a versatile high throughput immunoblot method

Lacking access to an affordable method of high throughput immunoblot analysis for daily use remains a big challenge for scientists worldwide. We proposed here Quantitative Dot Blot analysis (QDB) to meet this demand. With the defined linear range, QDB analysis fundamentally transforms traditional immunoblot method into a true quantitative assay. Its convenience in analyzing large number of samples also enables bench scientists to examine protein expression levels from multiple parameters. In addition, the small amount of sample lysates needed for analysis means significant saving in research sources and efforts. This method was evaluated at both cellular and tissue levels with unexpected observations otherwise would be hard to achieve using conventional immunoblot methods like Western blot analysis. Using QDB technique, we were able to observed an age-dependent significant alteration of CAPG protein expression level in TRAMP mice. We believe that the adoption of QDB analysis would have immediate impact on biological and biomedical research to provide much needed high-throughput information at protein level in this “Big Data” era.Lacking access to an affordable method of high throughput immunoblot analysis for daily use remains a big challenge for scientists worldwide. We proposed here Quantitative Dot Blot analysis (QDB) to meet this demand. With the defined linear range, QDB analysis fundamentally transforms traditional immunoblot method into a true quantitative assay. Its convenience in analyzing large number of samples also enables bench scientists to examine protein expression levels from multiple parameters. In addition, the small amount of sample lysates needed for analysis means significant saving in research sources and efforts. This method was evaluated at both cellular and tissue levels with unexpected observations otherwise would be hard to achieve using conventional immunoblot methods like Western blot analysis. Using QDB technique, we were able to observed an age-dependent significant alteration of CAPG protein expression level in TRAMP mice. We believe that the adoption of QDB analysis would have immediate impact on biological and biomedical research to provide much needed high-throughput information at protein level in this Big Data era.

Quantitative proteomic analysis of gastric cancer tissue reveals novel proteins in platelet-derived growth factor B signaling pathway

Gastric cancer is one of the most common cancers in Asian countries. Searching for reliable biomarkers involving the development of gastric cancer is important for clinical practice. Quantitative proteomics has become an important method contributed to the discovery of novel diagnostic or therapeutic targets for the management of cancer. Here, we identified differently expressed proteins in gastric cancer and normal gastric tissues by using the high resolution mass spectrometer. Among the total of 2280 identified proteins, 87 were differentially expressed between gastric cancer and normal gastric tissues. Notably, several significant proteins are in the PDGF-B signaling pathway, including peroxiredoxin5 (PRDX5), S100A6, calreticulin (CALR) and cathepsin D (CTSD), which were validated by western blot. Furthermore, upstream regulators including PDGF-B, PDGFR-β, Akt, eIF4E and p70s6K were found significantly increased in the gastric cancer tissues. In addition, silencing of PRDX5 and PDGF-B suppressed the proliferation of gastric cancer cells in vitro. The administration of exogenous PDGF-BB recovered the reduced expression of PDGF-B signaling pathway in PDGF-B knockdown cells. Taken together, our findings suggested that PDGF-B signaling pathway plays an important role in the regulation of gastric cancer proliferation and the inhibition of this pathway may be a potential approach for treatment of gastric cancer.

PDLIM5 identified by label-free quantitative proteomics as a potential novel biomarker of papillary thyroid carcinoma

In order to better understand the mechanisms underlying the development of papillary thyroid carcinoma (PTC), and to identify new potential biomarkers, high-resolution label-free mass spectrometry was performed on PTC tissues and adjacent normal thyroid tissues from six patients. In this process, 2788 proteins were identified, out of which 49 proteins presented significant differences between PTC tissues and adjacent normal thyroid tissues. Gene ontology revealed that the majority of these proteins are involved in the catalytic activity and binding. We selected three proteins with differential expressions: PDZ and LIM domain 5 (PDLIM5), PDLIM1 and ALDH1A1; Protein expressions were further verified by RT-PCR and western blot. Among these, expression of PDLIM5 and PDLIM1 was up-regulated, while that of ALDH1A1 was down-regulated in PTC tissues. Next, we confirmed their expression through quantitative dot blot (QDB) technique. We found that knockdown of PDLIM5 expression in the B-CPAP cell line could inhibit the migration, invasion and proliferation of PTC cells. In addition, PDLIM5 knockdown reduced Ras and Phospho-ERK1/2 expression. Thus, we suggested that PDLIM5 promotes PTC via activation of the Ras-ERK pathway. Our research provides new molecular insight into the function of PDLIM5, which may assist in studying the mechanism of PTC. In addition, PDLIM5 could be further explored as a potential candidate for PTC treatment.

A systematic review and meta-analysis: Does hepatitis C virus infection predispose to the development of chronic kidney disease?

We aimed to meta-analytically assess the predisposition of hepatitis C virus (HCV) infection to the occurrence and severity of chronic kidney disease (CKD). Two authors independently searched articles and abstracted information. Odds ratio (OR) or hazard ratio (HR) along with 95% confidence interval (CI) was converged separately in 12 longitudinal (1,972,044 subjects) and 15 cross-sectional (937,607 subjects) studies. Overall effect estimate was remarkably significant in longitudinal studies (HR, 95% CI, P: 1.45, 1.23-1.71, < 0.001), in contrast to that in cross-sectional studies (OR, 95% CI, P: 1.25, 0.90-1.73, 0.188), with obvious heterogeneity (I2 > 95%). HCV infection was also associated with an 1.54-fold (95% CI, P: 1.27-1.87, < 0.001) increased risk of having prevalent proteinuria. In longitudinal studies with estimated glomerular filtration rate (eGFR) < 60, < 30 and < 15 ml/min/1.73m2, the corresponding HR was 1.39 (95% CI, P: 1.14-1.69, 0.001), 1.79 (0.91-3.51, 0.091) and 2.30 (1.26-4.19, 0.007). Further grouping the longitudinal studies by median follow-up time at 5 years revealed that the effect estimate was reinforced in long-term studies (HR, 95% CI, P: 1.86, 1.19-2.89, 0.006; I2=98.1%) relative to that in short-term studies (1.21, 1.03-1.43, 0.024; 92.0%). In conclusion, our findings demonstrate the significant risk of experiencing incident CKD after HCV infection, with the lower eGFR and longer HCV exposure time entailing a greater risk.

The impact of interleukin-10 (IL-10) gene 4 polymorphisms on peripheral blood IL-10 variation and prostate cancer risk based on published studies

This study purported to investigate the impact of interleukin-10 (IL-10) gene 4 polymorphisms (−1082G>A, -819T>C, -592A>C and 210T>C) on peripheral blood IL-10 variation and prostate cancer (PCa) risk, with a special consideration given to various origins of between-study heterogeneity. 2 researchers independently fulfilled literature retrieval, quality assessment and information collection. Sub-grouped analyses per ethnicity, continent, design type, control source, genotyping procedure, genotype validation, age-matched status, study sample size, quality score and controls’ mean age were conducted, respectively. Total 17 unduplicated studies (patients/controls: 7561/8101) were assessable for PCa risk, and 4 unduplicated studies (1189 subjects) for peripheral blood IL-10 variation. Pooling all assessable studies identified a marginally significant association between the -1082A allele and increased PCa risk (odds ratio (OR)=1.10, 95% confidence interval [CI]: 1.00 to 1.21) (Heterogeneity I2=64.3%), and no significance was detected in sub-grouped analyses of this polymorphism. Contrastingly, the -592C allele was significantly associated with reduced PCa risk in both prospective (OR=0.85, 95% CI: 0.77 to 0.95) and population-based (OR=0.92, 95% CI: 0.84 to 1.00) studies (Heterogeneity I2=0.0% and 18.1%). Moreover, carriers of combined -592CA/CC genotypes had a significant higher level of peripheral blood IL-10 than the -592AA genotype carriers (weighted mean difference=0.45 and 0.54 mg/dL, 95% CI: 0.23 to 0.67 and 0.30 to 0.39). The above comparisons possessed a low probability of publication bias. In sum, our findings suggested that IL-10 gene -592A>C polymorphism may represent a promising candidate locus for the occurrence of PCa, and further signified a contributing role of this polymorphism in prostate carcinogenesis.

The Number of Stenotic Intracranial Arteries Is Independently Associated with Ischemic Stroke Severity

Background The severity of ischemic stroke symptoms varies among patients and is a critical determinant of patient outcome. To date, the association between the number of stenotic intracranial arteries and stroke severity remains unclear. Aims We aimed to investigate the association between the number of stenotic major intracranial arteries (NSMIA) and ischemic stroke severity, as well as the degree of stenosis and common stroke risk factors. Methods We performed a retrospective analysis of patients with digital subtraction angiography (DSA)-confirmed ischemic stroke. Clinical stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). The number of stenotic vessels was counted from the internal carotid arteries and vertebral arteries, bilaterally. Results Eighty three patients were recruited from a single center and included in the study. NSMIA was significantly correlated with stroke severity (Pearson Correlation Coefficient = 0.485, P < 0.001), but not with the degree of stenosis (Pearson Correlation Coefficient = 0.01, P = 0.90). Multivariate regression analysis revealed that NSMIA was significantly associated with the NIHSS score after adjusting for stroke risk factors. The adjusted odds ratio (per lateral) was 2.092 (95% CI, 0.865 to 3.308, P = 0.001). The degree of stenosis was also significantly associated with the NIHSS score after adjusting for common risk factors. The odds ratio (per 10%) was 0.712 (95% CI, 0.202 to 1.223, P = 0.007). Conclusions The number of stenotic intracranial major arteries is associated with the severity of ischemic stroke independent of the degree of stenosis and other stroke risk factors. To the best of our knowledge, this has not been previosuly studied in great detail using DSA. Our data highlight the importance of examining all major arteries in stroke patients.

Relationship Between Interleukin-10 Gene C-819T Polymorphism and Gastric Cancer Risk: Insights From a Meta-Analysis

Background As a pleiotropic cytokine, interleukin-10 (IL-10) plays a regulatory role in carcinogenesis and tumor growth. The aim of this meta-analysis was to assess the susceptibility of the IL-10 gene C-819T polymorphism to gastric cancer. Material/Methods Study identification and data extraction were independently completed by 2 authors. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated and summarized. Results In total, 11 articles including 1960 gastric cancer patients and 3705 controls were qualified. Overall analyses revealed a 13% reduced risk of gastric cancer conferred by the −819T allele relative to the −819C allele (OR=0.87; 95% CI: 0.77–0.97; P=0.016), without heterogeneity (I2=35.1%). In subgroup analyses, a significant difference was identified in East Asian populations (OR=0.85; 95% CI: 0.73–0.98; P=0.029, I2=43.6%), for gastric adenocarcinoma (OR=0.80; 95% CI: 0.66–0.96; P=0.017, I2=0.0%), and in population-based studies (OR=0.81; 95% CI: 0.70–0.93; P=0.003, I2=0.0%). The visual funnel plots and Egger’s tests suggested no evidence of publication bias. Conclusions Extending previous findings, we demonstrate a protective role of the IL-10 gene −819T allele in susceptibility to gastric cancer, and this role was more evident for gastric adenocarcinoma.

High Throughput, Absolute Determination of the Content of a Selected Protein at Tissue Levels Using Quantitative Dot Blot Analysis (QDB)

Lacking a convenient, quantitative, high throughput immunoblot method for absolute determination of the content of a specific protein at cellular and tissue level significantly hampers the progress in proteomic research. Results derived from currently available immunoblot techniques are also relative, preventing any efforts to combine independent studies with a large-scale analysis of protein samples. In this study, we demonstrate the process of quantitative dot blot analysis (QDB) to achieve absolute quantification in a high throughput format. Using a commercially available protein standard, we are able to determine the absolute content of capping actin protein, gelsolin-like (CAPG) in protein samples prepared from three different mouse tissues (kidney, spleen, and prostate) together with a detailed explanation of the experimental details. We propose the QDB analysis as a convenient, quantitative, high throughput immunoblot method of absolute quantification of individual proteins at the cellular and tissue level. This method will substantially aid biomarker validation and pathway verification in various areas of biological and biomedical research.