Genetic and epigenetic predispositions underlying cardiovascular outcomes among patients treated with clopidogrel and aspirin / 中国药理学与毒理学杂志

Coronary artery disease (CAD)is a major cause of death and disability worldwide, and consumes a considerable amount of medical resources every year.Clopidogrel is a first-line antiplate-let therapy for CHD, butit is associated with substantial variability in PK and pharmacodynamics re-sponse. To date, gene variants explain only a smallproportion of the variability.The study aimed to identify new genetic loci-modifying antiplatelet response to clopidogrel in Chinese patients with CAD by a systematic analysis combining antiplatelet effects and PK, and further to investigate the PON1 gene promoter DNA methylation and genetic variations possibly influencing clinical outcomes in pa-tients undergoing PCI. We identified novel variants in two transporter genes (SLC14A2rs12456693, ATP-binding cassette [ABC]A1 rs2487032) and in N6AMT1 (rs2254638) associated with P2Y12 reac-tion unit (PRU) and plasma active metabolite (H4) concentration. These new variants dramatically im-proved the predictability of PRU variability to 37.7％. The associations between these loci and PK pa-rameters of clopidogrel and H4 were observed in additional patients, and its function on the activation of clopidogrel was validated in liver S9 fractions (P<0.05). Rs2254638 was further identified to exert a marginal risk effect formajor adverse cardiac events in an independent cohort.Multivariate logistic regression analysis indicated that PON1methylation level at CpG site-161 (OR=0.95; 95％ CI=0.92–0.98;P<0.01)and the use of angiotensin converting enzyme inhibitors(OR=0.48;95％ CI=0.26–0.89;P<0.01) were associated with decreased risk of bleeding events. In conclusion, new genetic variants were systematically identified as risk factors for the reduced efficacy of clopidogrel treatment.The ab-normal expression of DNA methylation-regulating key genes in the pharmacokinetic and pharmacody-namics pathways of clopidogrel and aspirin may modify clinical outcomes in dual antiplatelet-treated pa-tients undergoing PCI.

Hepatitis B virus X promotes HepG2 cell cycle progression and growth via downregulation expression of p16 protein / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the effects and related mechanisms of hepatitis B virus X (HBx) protein on cell cycle and growth in hepatocellular carcinoma.</p><p><b>METHODS</b>A human hepatocyte HepG2 cell line stably expressing a green fluorescent protein (GFP)-tagged HBx (HepG2/GFP-HBx cells) was used for the experiment, and HepG2 parental and HepG2/GFP cells was used as the controls. Effect of HBx on cell growth was evaluated by the MTT cell proliferation assay and on cell cycle progression by flow cytometry analysis of cells with or without treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR; 5 pmol/L). Effect of HBx expression on promoter methylation status of the p16INK4A tumor-suppressor gene was detected by methylation-specific polymerase chain reaction and on p16 protein level was analyzed with western blotting.</p><p><b>RESULTS</b>The HepG2/GFP-HBx cells showed significantly higher cell proliferation at 72 hrs of culture (3.225+/-0.038 A490) than either control (HepG2: 2.012+/-0.022 A490, t = -46.86, P less than 0.001; HepG2/GFP: 2.038+/-0.029 A490, t = 42.51, P less than 0.001). The HepG2/GFP-HBx cells also showed significantly lower proportion of cells in the G0/G1 phase (16.45%+/-0.45%) than either control (HepG2: 44.81%+/-1.36%, t = -34.202, P less than 0.001; HepG2/GFP: 42.76%+/-1.58%, t = -28.88, P less than 0.001). However, 5-Aza-CdR treatment did lead to a significant amount of HepG2/GFP-HBx cells being arrested in the G0/G1 phase (33.25%+/-0.79%, t = 31.85, P less than 0.001). The p16INK4A promoter was methylated in the HepG2/GFP-HBx cells, and became demethylation after treatment with 5-Aza-CdR. However, no methylation of p16INK4A promoter was observed in both HepG2 and HepG2/GFP cells. The p16 protein level was significantly lower in the HepG2/GFP-HBx (vs. HepG2 and HepG2/GFP cells) and this level increased after treatment with 5-Aza-CdR.</p><p><b>CONCLUSION</b>HBx protein promotes hepatocellular carcinoma cell cycle progression and growth by shortening the G0/G1 phase, and the underlying mechanism may involve inducing p16INK4A promoter methylation and downregulating p16 protein expression.</p>

Small interfering RNA targeting to hepatitis B virus X gene and 5-aza-2'-deoxycytidineon inhibited growth of the subcutaneous implanted tumor of hepatocellular carcinoma in nude mice / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the anti-tumor effect of small interfering RNA targeting to HBV X gene (X-siRNA) and 5-aza-2'-deoxycytidine (5-aza-dC) on HBV-related hepatocellular carcinoma.</p><p><b>METHODS</b>X-siRNA and control siRNA were synthesized. HepG2/GFP-HBx cells were treated with X-siRNA, and the levels of HBV X mRNA were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Nude mice were inoculated with HepG2/GFP and HepG2/GFP-HBx cells subcutaneous respectively to establish implant models of hepatocellular carcinoma, and were treated with X-siRNA, 5-aza-dC alone or in combination, and tumor growth was observed. The methylation of p16 gene promoter was detected by methylation specific polymerase chain reaction (MSP).</p><p><b>RESULTS</b>RT-PCR showed the expression of HBV X mRNA in HepG2/GFP-HBx cells was inhibited markedly by X-siRNA. The nude mice experiment showed that the gross tumor volume was much bigger in HepG2/GFP-HBx group than that in HepG2/GFP group (P < 0.05). The growth of palpable tumors in X-siRNA or 5-aza-dC treatment group notably decreased (P < 0.05). MSP analysis showed that p16 gene methylation was observed in HepG2/ GFP-HBx-caused palpable tumors, while no methylation was detected in HepG2/GFP group. However, after treatment with X-siRNA or 5-aza-dC, p16 gene methylation reduced.</p><p><b>CONCLUSIONS</b>HBV X-siRNA and methylation inhibitor can inhibit the growth of hepatoma cells via reversing p16 methylation.</p>

Progress in genetic and epigenetic research on in-stent restenosis after percutaneous coronary interventions / 中华医学遗传学杂志

Coronary heart disease is one of the most important causes of death in human, and consumes vast medical resources. Percutaneous coronary intervention (PCI) has been a significant breakthrough for its treatment. However, clinical application has been hampered by in-stent restenosis (ISR). Although drug eluting stent (DES) has reduced the occurrence of restenosis, incidence of ISR is still about 5% to 10%. The main reasons for restenosis after PCI are hyperplasia of vascular endothelial cells and smooth muscle cell migration. The exact mechanism of personalized differences in restenosis is not clear yet, but there may be a variety of risk factors. In addition to aging, smoking and diabetes, an increasing number of studies have found that genetic and epigenetic factors play an important role in ISR. In this article, authors have reviewed genetic and epigenetic factors on the progression of ISR, which may help to determine the genetic risk factors in patients with ISR after PCI.