Aberrantly Methylated cfDNA in Body Fluids as a Promising Diagnostic Tool for Early Detection of Breast Cancer

Breast malignancies are the leading type of cancer among women. Its prevention and early detection, particularly in young women, remains challenging. To this end, cell-free DNA (cfDNA) detected in body fluids demonstrates great potential for early detection of tissue transformation and altered molecular setup, such as epigenetic profiles. Aberrantly methylated cfDNA in body fluids could therefore serve as a potential diagnostic and prognostic tool in breast cancer management. Abnormal methylation may lead to both an activation of oncogenes via hypomethylation and an inactivation of tumor suppressor genes by hypermethylation. We update the state of the art in the area of aberrant cfDNA methylation analyses as a diagnostic and prognostic tool in breast cancer, report on the main technological challenges, and provide an outlook for advancing the overall management of breast malignancies based on cfDNA as a target for diagnosis and tailored therapies.     

Structural brain correlates of serum and epigenetic markers of inflammation in major depressive disorder

Inflammatory processes are implicated in the aetiology of Major Depressive Disorder (MDD); however, the relationship between peripheral inflammation, brain structure and depression remains unclear, partly due to complexities around the use of acute/phasic inflammatory biomarkers.Here, we report the first large-scale study of both serological and methylomic signatures of CRP (considered to represent acute and chronic measures of inflammation respectively) and their associations with depression status/symptoms, and structural neuroimaging phenotypes (T1 and diffusion MRI) in a large community-based sample (Generation Scotland; N_{MDD cases} = 271, N_controls = 609).Serum CRP was associated with overall MDD severity, and specifically with current somatic symptoms- general interest (β = 0.145, P_FDR = 6 × 10⁻⁴) and energy levels (β = 0.101, P_FDR = 0.027), along with reduced entorhinal cortex thickness (β = −0.095, P_FDR = 0.037). DNAm CRP was significantly associated with reduced global grey matter/cortical volume and widespread reductions in integrity of 16/24 white matter tracts (with greatest regional effects in the external and internal capsules, β_FA= −0.12 to −0.14). In general, the methylation-based measures showed stronger associations with imaging metrics than serum-based CRP measures (βaverage = −0.15 versus βaverage = 0.01 respectively).These findings provide evidence for central effects of peripheral inflammation from both serological and epigenetic markers of inflammation, including in brain regions previously implicated in depression. This suggests that these imaging measures may be involved in the relationship between peripheral inflammation and somatic/depressive symptoms. Notably, greater effects on brain morphology were seen for methylation-based rather than serum-based measures of inflammation, indicating the importance of such measures for future studies.     

肺癌miR-146a表达及其对细胞增殖、侵袭及迁移的影响

目的探讨微小RNA-146a(miR-146a)在肺癌组织和细胞中的表达和甲基化状态,及其对A549细胞增殖、侵袭、迁移的影响及可能机制。方法收集2018年1月至2019年4月在我院行根治性手术的非小细胞肺癌组织和对应癌旁组织,实时荧光定量PCR(QPCR)和甲基化特异性PCR(MSP)检测miR-146a的表达水平和甲基化状态,并分析甲基化状态与肺癌临床病理特征的关系。采用5-氮杂-2’-脱氧胞苷(5-AZA-2’-dC)处理A549细胞(处理组),MTT、Transwell实验和划痕实验检测处理组细胞增殖、侵袭和迁移活性。采用Western blotting检测Notch1和发状分裂相关增强子1(Hes-1)蛋白表达。结果肺癌组织和A549细胞中miR-146a表达量分别为0.63±0.28、0.85±0.11,均低于癌旁正常组织和BEAS-2B细胞(P<0.05)。MSP检测显示肺癌组织miR-146a甲基化率为62.5%(50/80),高于癌旁组织(P<0.05);miR-146a甲基化状态与肿瘤直径、TNM分期、淋巴结转移有关(P<0.05)。处理组细胞miR-146a表达水平为2.15±0.48,高于空白对照组(P<0.05);处理组细胞增殖、侵袭和迁移活性均低于空白对照组(P<0.05)。处理组Notch1蛋白和Hes-1蛋白表达水平分别为0.24±0.05和0.22±0.06,均低于空白对照组(P<0.05)。结论启动子异常甲基化导致在肺癌组织和细胞中miR-146a表达量降低,可能通过减弱对Notch1/Hes-1信号通路的抑制作用,促进肺癌细胞增殖、侵袭和转移,miR-146a有望成为肺癌新的生物治疗靶点。     

胃癌组织中PDCD4基因的表达和甲基化水平及其临床意义

目的 观察胃癌组织中抑癌基因PDCD4启动子区甲基化状态及其对PDCD4表达水平的影响并探讨其临床意义。方法 通过免疫组织化学、Western blot法检测胃癌组织中PDCD4蛋白的表达；RT-PCR法检测PDCD4 mRNA的表达；甲基化特异性PCR（MSP）法检测PDCD4启动子区甲基化水平。分析PDCD4表达水平以及启动子甲基化水平与胃癌患者临床病理特征之间的相关性。结果 胃癌组织中PDCD4蛋白及mRNA表达水平均显著降低（P<0.05），甲基化作用显著增强（P<0.05）。PDCD4蛋白表达缺失与胃癌的分化、临床分期以及淋巴结转移密切相关（P<0.05）；PDCD4高甲基化与胃癌的淋巴结转移、临床分期密切相关（P<0.05）。PDCD4甲基化水平与PDCD4蛋白以及mRNA表达水平均呈负相关（P<0.05）。结论 胃癌组织中PDCD4表达水平显著降低，并与胃癌发展相关，启动子区高甲基化可能是PDCD4表达缺失的原因。     

EphB6受体在恶性肿瘤中的研究进展

受体酪氨酸激酶(RTKs)是一种主要的膜受体,调控细胞增殖、分化和迁移。解除RTK信号通路的管制会导致许多疾病,如癌症和发育障碍。促红细胞生成素肝细胞受体(Erythropoietin-producing hepatocellular,Eph)家族是酪氨酸激酶受体家族中最大的一个亚族,其与配体Ephrin的相互作用在生长发育和肿瘤发生过程中发挥着重要作用。研究表明,一种缺乏酪氨酸激酶活性的特殊Eph受体EphB6在乳腺癌、结直肠癌等许多恶性肿瘤中表达下降,而大量证据表明EphB6表达的缺失依赖于其启动子DNA的高甲基化,进而促进肿瘤的进展与转移。EphB6是近期研究的热点因子,本文就其目前在恶性肿瘤中研究进展做一综述。     

Hepatitis B virus X protein boosts hepatocellular carcinoma progression by downregulating microRNA-137

BackgroundHepatocellular carcinoma (HCC) is a frequent diagnosed malignancy. microRNAs (miRs) are involved in various cellular processes during cancer development. This study attempted to probe the miR-based mechanism in hepatitis B virus X protein (HBx) small interfering RNA (siRNA)-treated HCC cells.MethodsHBx expression in hepatocyte and HCC cells was detected, and cells with highest HBx expression were screened out and transfected with HBx-siRNAs. Then the effect of HBx on HCC cell proliferation was detected. miRs differentially expressed in HBx-siRNA-transfected MHCC97H cells were analyzed and verified. miR-137 methylation was analyzed by bioinformatics, and miR-137 restoration was detected after Aza treatment. Furthermore, miR-137 methylation in MHCC97H cells with HBx knockdown or HBx overexpression was detected by methylation specific PCR. The targeting relationship between miR-137 and Notch1 was verified. Then the gain-and-loss functions of miR-137 or/and Notch1 were performed to estimate their roles in HCC cell proliferation. The effects of HBx-siRNA and overexpressed miR-137 in vivo were observed by tumor xenograft in nude mice and immunohistochemistry.ResultsHBx-siRNA weakened MHCC97H cell proliferation and tumor growth. miR-137 was highly expressed in HBx-siRNA-treated HCC cells and targeted Notch1. HBx knockdown decreased miR-137 methylation and restored miR-137 expression. miR-137 overexpression prevented HCC cell proliferation and tumor growth, while miR-137 downregulation reversed the repressing effects of HBx-siRNA on HCC cell proliferation. Inhibition of Notch1 reversed HCC cell proliferation induced by miR-137 downregulation.ConclusionOverexpression of miR-137 blocks HCC cell proliferation in HBx-siRNA-treated MHCC97H cells by targeting Notch1. This study may offer novel target for HCC treatment.     

Genetic and epigenetic alterations of the EGFR and mutually independent association with BRCA1, MGMT,and RASSF1A methylations in Vietnamese lung adenocarcinomas

Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.