Association of <em>microRNA-499</em> rs3746444 Polymorphism with Cancer Risk: Evidence from 7188 Cases and 8548 Controls

<div><h3>Background</h3><p>Owing to inconsistent and inconclusive results, we performed a meta-analysis to derive a more precise estimation of the association between <em>miR-499</em> rs3746444 polymorphism and cancer risk.</p> <h3>Methodology/Principal Findings</h3><p>A systematic search of the Pubmed, Excerpta Medica Database (Embase) and Chinese Biomedical Literature Database (CBM) databases was performed with the last search updated on May 6, 2012. The odds ratio (OR) and its 95% confidence interval (95%CI) were used to assess the strength of the association. A total of 15 independent studies including 7,188 cases and 8,548 controls were used in the meta-analysis. In the present meta-analysis, we found a significant association between <em>miR-499</em> rs3746444 polymorphism and cancer risk in the overall analysis (G versus A: OR = 1.10, 95%CI 1.01–1.19, <em>P</em> = 0.03; GG+AG versus AA: OR = 1.15, 95%CI 1.02–1.30, <em>P</em> = 0.02; GG versus AG+AA: OR = 1.07, 95%CI 0.89–1.28, <em>P</em> = 0.50; GG versus AA: OR = 1.13, 95%CI 0.98–1.31, <em>P</em> = 0.09; AG versus AA: OR = 1.16, 95%CI 1.02–1.33, <em>P</em> = 0.03). In the subgroup analysis by ethnicity, <em>miR-499</em> rs3746444 polymorphism was significantly associated with cancer risk in Asian population. In the subgroup analysis by cancer types, <em>miR-499</em> rs3746444 polymorphism was significantly associated with breast cancer.</p> <h3>Conclusions/Significance</h3><p>This meta-analysis suggests a significant association between <em>miR-499</em> rs3746444 polymorphism and cancer risk. Large-scale and well-designed case-control studies are necessary to validate the risk identified in the present meta-analysis.</p> </div

Meta-analysis of <i>miR-499</i> rs3746444 polymorphism with cancer susceptibility.^*

*<p>OR, odds ratio; vs, versus; R, random effect model; F, fixed effect model.</p

Characteristics of studies included in the meta-analysis.^*

*<p>CSCC, cervical squamous cell carcinoma; SCCHN, squamous cell carcinoma of head and neck; HWE, Hardy-Weinberg equilibrium.</p

Growth of islets in each group after 4 days of cultivation (×40).

<p>(AO/EB staining, a–d: MCT group, Ficoll-400 group, 1077 group, and HPU group, respectively).</p

Islet purity and viability assays in each group (×20).

<p>(A: Result of Trypan blue staining and de-staining, B: Result of DTZ staining, a–d: MCT group, Ficoll-400 group, 1077 group, and HPU group, respectively).</p

Device and flow chart of islet isolation and purification.

<p>(1. Centrifuge cap; 2. Matte surface of tube outer wall; 3. Pancreatic tissue; 4. Coarse sieve; 5 and 8. Detachable joints; 6. Islets; 7. Fine sieve; 9. Single-cell suspension; A. Upper tube section; B. Middle tube section; C and D. Lower tube section.); DD, device description; AP, acquisition of pancreas; IP, inverted position; DWB, digestion in water bath; UP, upright position; IP, islet purification; SD, second digestion; IC, islet collection.</p

Egger's linear regression test to measure the funnel plot asymmetric.^*

*<p>vs, versus.</p

Comparison of parameters of the four methods for the isolation and purification of islet cell clumps (6 experiments/group).

<p>Comparison of parameters of the four methods for the isolation and purification of islet cell clumps (6 experiments/group).</p

Flow diagram of the study selection process.

<p>Flow diagram of the study selection process.</p

Interleukin-35 mitigates the function of murine transplanted islet cells via regulation of Treg/Th17 ratio

<div><p>Pancreatic islet transplantation is a promising treatment for type 1 diabetes (T1D). Interleukin-35 (IL-35) is a recently discovered cytokine that exhibits potent immunosuppressive functions. However, the role of IL-35 in islet transplant rejection remains to be elucidated. In this study, we isolated islet cells of BALB/c mouse and purified CD4+ T cell subsets of a C57BL/6 mouse. The model for islet transplantation was established <i>in vitro</i> by co-culture of the islet cells and CD4+ T cells. IL-35 (20 ng/ml) was administered every other day. Following co-culture, the islet function and Treg/Th17 ratio were analyzed on days 1, 3, and 5. Furthermore, the Th17/Treg ratio was modulated (1:0–2), and the function of islet cells as well as proliferation of Th17 cells were analyzed. T cell sorting was performed using the magnetic bead sorting method; Treg and Th17 count using flow cytometry; cell proliferation detection using the carboxyfluorescein diacetate succinimidyl ester (CFSE) method, and islet function test using the sugar stimulation test. Results showed that Th17 counts increased in the co-culture system. However, after administration of IL-35, the number of Treg cells increased significantly compared to that in the control group (50.7% of total CD4+ T cells on day 5 in IL-35 group vs. 9.5% in control group) whereas the proliferation rate of Th17 cells was significantly inhibited (0.3% in IL-35 group vs. 7.2% in control group on day 5). Reducing the Th17/Treg ratio significantly improved the function of transplanted islets. Treg inhibited Th17 proliferation and IL-35 enhanced this inhibitory effect. IL-35 mitigates the function of murine transplanted islet cells via regulation of the Treg/Th17 ratio. This might serve as a potential therapeutic strategy for in-vivo islet transplant rejection and T1D.</p></div