m6A结合蛋白IGF2BP1在肝细胞癌中的基因调控网络分析

目的 分析m6A阅读器胰岛素样生长因子2-mRNA结合蛋白1（insulin-like growth factor 2 mRNA-binding protein 1，IGF2BP1）在肝细胞癌（hepatocellular carcinoma，HCC）中的表达水平及其对HCC患者预后的影响，并探讨IGF2BP1在HCC发生发展中的作用及其潜在机制。方法 基于5对HCC癌及相应癌旁组织mRNA-seq数据和TCGA数据库LIHC的mRNA-seq数据综合分析IGF2BP1在HCC中的表达情况，同时利用TCGA数据库中343例HCC患者的临床随访资料分析IGF2BP1表达水平对HCC患者总生存期的影响。基于TCGA数据库筛选IGF2BP1的共表达mRNA，并利用m6Avar在线网站预测mRNA的m6A位点及其RNA结合蛋白等信息，最终构建IGF2BP1的基因调控网络。结果 IGF2BP1基因在HCC中表达上调（log2FC HCC转录组数据=10.684，P<0.001；log2FC TCGA-LIHC数据集=7.032，P<0.001）。生存分析显示IGF2BP1低表达的HCC患者中位生存时间为5.84年，IGF2BP1高表达患者为4.44年，高表达患者总生存期缩短（P=0.011）。22个差异表达的mRNA与IGF2BP1存在靶向结合关系，并与其表达水平呈正相关。其中，HMGA2等15个高表达mRNA的HCC患者总生存期缩短。HMGA2、PEG10、CEP55、RHO、CDC6和KIF23基因中的潜在m6A甲基化位点位于mRNA 3'UTR端的miRNA结合区域。结论 IGF2BP1在HCC中高表达且导致患者总生存期缩短。IGF2BP1可能通过m6A甲基化及miRNA抑制作用的方式上调mRNA的表达，促进HCC发生并导致不良预后。     

庆大霉素对豚鼠前庭上皮IGF-1及其受体表达的影响

目的：研究庆大霉素对豚鼠前庭上皮胰岛素样生长因子-1（insulin-like growth factor-1，IGF-1）及其受体（insulin-like growth factor-1 receptor，EGF-1R）表达的影响，并探讨其生物学特性。方法：采用免疫组织细胞化学方法，以抗IGF-1及IGF-1R抗体为标记物，检测庆大霉素损伤后豚鼠前庭上皮自发修复期IGF-1及IGF-1R的表达变化和分布特点；采用Brdu体内标记和抗Brdu抗体免疫组化染色，检测庆大霉素损伤后豚鼠前庭上皮增殖的变化。结果：IGF-1及IGF-1R在正常成年豚鼠前庭上皮细胞中有低水平表达，庆大霉素损伤后，其表达增多。在1d组IGF-1及IGF-1R表达最强，其后逐渐减少。在正常对照组中无Brdu阳性细胞。各实验组均观察到Brdu阳性细胞，7d组最多。结论：庆大霉素损伤后，豚鼠前庭上皮IGF-1及IGF-1R表达增强，其时程变化与细胞增殖活动密切相关。IGF-1在豚鼠前庭上皮损伤后的细胞增殖中可能起重要信号转导作用。     

胰岛素样生长因子-1在妇科疾病中的作用

在许多组织增生过程中，通过内分泌、旁分泌和自分泌会产生胰岛素样生长因子-1(IGF-1)。最近的研究发现，IGF-1存在于各种增生组织，如子宫内膜和卵巢组织。患有严重子宫内膜异位症时，血清中IGF-1水平较高，而子宫内膜局部的：IGF-1水平减低，这可能是导致不孕的原因，多囊性卵巢综合征(PCOS)患者卵巢局部的IGF-1活性增强，与患者肥胖、高雄激素水平等一系列临床症状有关。IGF-1在良、恶性肿瘤中也起着重要的作用，IGF-1能刺激子宫肌瘤细胞的生长。围绝经期妇女若存在高IGF-1和低IGF-1结合蛋白-3(IGFBP-3)水平，则患乳腺癌的风险增大。绝经前后女性的高IGF-1水平与宫颈癌、卵巢癌和子宫内膜癌的发病率存在相关性。     

胰岛素样生长因子-1受体在子宫内膜癌中的表达及临床意义

目的 研究子宫内膜癌组织中IGF-1R的分布、表达及其临床意义。方法 选取30例子宫内膜癌手术标本，石蜡切片，采用PV-600PicTureTM检测试剂进行免疫组化，测定IGF-1R的分布及表达，分析与临床病理之间的关系。另取10例正常的增生期子宫内膜标本作为对照。结果 IGF-1R为膜受体。IGF-1R在10例正常增生期子宫内膜细胞中的阳性表达率为70％，无过度表达；而在30例子宫内膜癌细胞中的阳性表达率为90％，过度表达率为40％（中度阳性7例、强阳性5例）。统计表明，正常增生期子宫内膜细胞与子宫内膜癌细胞相比IGF-1R阳性表达率差异尤显著性（P=0．13）；IGF-1R过度表达率差异有显著性（P=0．017）。子宫内膜癌细胞膜IGF-1R阳性表达及过度表达在高分化与中、低分化之间有显著差异（与分级呈负相关系：分化越低，IGF-1R的表达越强，反之，分化高，IGF-1R的表达则弱）。IGF-1R的阳性表达及过度表达在临床分期Ⅰ-Ⅲ期各组间均无明显差异。结论 IGF-1R在子宫内膜癌细胞膜表达，且随恶性程度的增加其表达量增加，IGF-1R的表达量可以预测内膜癌的预后，对临床治疗可能具有一定的指导意义。     

Serum Levels of Free Insulin-Like Growth Factor (IGF)-I in Normal Children

Serum levels of free insulin-like growth factor (IGF)-I were measured by immunoradiometric assay (IRMA) in fasting sera of 137 normal boys and 120 normal girls aged from 8 to 15 yr to study relationships between free IGF-I levels and ages, total IGF-I, IGF binding protein (IGFBP)-1, IGFBP-3, and acid-labile subunit (ALS) levels. In both sexes, serum free IGF-I levels and the ratios of free IGF-I to total IGF-I were significantly higher in the pubertal age groups than in the prepubertal age groups. Serum levels of free IGF-I showed a significant positive correlation with those of total IGF-I, IGFBP-3 and ALS, while they showed a significant negative correlation with those of IGFBP-1. These observations suggest that increase in serum free IGF-I levels during puberty is caused by a dramatic increase in total IGF-I, rather than IGFBP-3, and a decrease in IGFBP-1. Also, high free IGF-I levels may play an important role in pubertal growth spurt.     

Regulatory effects of biophysical strain on rat TMJ discs

Recent studies have revealed that dynamic biomechanical forces can exert antiinflammatory and antiproteolytic effects on fibrocartitage. Whether the effects of mechanical strain also involve stimulation of the insulin-like growth factor (IGF) system and, therefore, of growth and repair of fibrocartilage has yet to be determined. The objective of this in vitro study was to determine if continuous biophysical strain regulates the gene expression of IGF1, IGF2, IGF1 receptor (IGF1R), insulin receptor substrate (IRS1), and IGF-binding proteins (IGFBP) 3 and 5 in cells from the fibrocartilaginous disc of the temporomandibular joint (TMJ). Rat TMJ disc cells were subjected to continuous biophysical strain (3% and 20%) for 4 and 24 h. Subsequently, RNA was extracted and real-time PCR was performed using an iCycler iQ detection system to analyze the gene expression of the IGF system. The gene expression of IGF1, IGF2, IGF1R, IRS1, IGFBP3, and IGFBP5 was significantly (p < 0.05) inhibited when cells were subjected to continuous biophysical strain, as compared to control at both time points. High strain induced a stronger inhibition of these molecules as compared to strain of Low magnitude. In conclusion, continuous biophysical strain seems to downregulate the expression of the IGF system and may, therefore, reduce the potential of fibrocartilage for growth and repair.     

Candidate genes associated with ageing and life expectancy in the Jerusalem longitudinal study

In an exploratory study, 11 common polymorphisms were examined for contributing to longevity including: apolipoprotein E (apoE), methylenetetrahydrofolate reductase (MTHFR), cathepsin D (CAD), superoxide dismutase 2 (SOD2), angiotensinogen (AGT) and insulin-like growth factor 2 (IGF2), Leiden factor 7, p53 oncogene, dopamine D4 receptor (DRD4) and the serotonin transporter (SERT). Genotype and allele frequencies of these genes were compared in 224 older (75 years) Jewish Jerusalem residents of Ashkenazi ethnicity to a group of 441 younger subjects (22 years). Nominally significant results provide suggestive evidence in the Ashkenazi group that apoE, MHTFR, SOD2, IGF2 ApaI, and factor VII are risk factors for a single outcome, survival to 75. Overall, the more genetically homogenous Ashkenazi ethnic group showed evidence for association in five genes examined suggesting that future studies in this population would gainfully focus on this ethnic group.     

Genomic imprinting and its relevance to genetic diseases

Summary Genomic imprinting is a biological phenomenon determined by an evolutionally acquired, underlying system that may control harmonious development and growth in mammals. It is also relevant to some genetic disorders in man. In this article, lines of biological evidence of imprinting, characteristics of the mouse and human imprinted genes, and findings and mechanisms on the occurrence of several human imprinting disorders are reviewed.     

Messenger RNA encoding the insulin-like growth factors and their binding proteins, in women with fibroids, pretreated with luteinizing hormone-releasing hormone agonists

The primary objective of this study was to suggest a possiblemechanism of action of luteinizing hormone-releasing hormoneagonist (LHRHa) on fibroids. This was performed by investigatinginsulin-like growth factor (IGF)-I, IGF-II and IGF binding protein(IGFBP)-1, -2 and -3 mRNA expression in uterine fibroids fromwomen rendered hypo-oestrogenic by LHRHa, using Northern blotanalysis. Nine women with fibroids, who were rendered hypo-oestrogenicfrom at least 4 months pretreatment with LHRHa therapy priorto undergoing myomectomy were investigated. Our results showedthat IGF-I, IGF-II, IGFBP-2 and -3 mRNAs were expressed in uterinefibroids, and that IGFBP-1 mRNA or protein was not detectedin fibroids. Western ligand blotting showed the presence ofIGFBP-2 and -3 proteins, and when compared with a group of womenwith fibroids not treated with LHRHa (B.J.Vollenhoven et al.,1993, J. Clin. Endocrinol Metab., 76, 1106–1110) we foundthat there was no difference in the relative abundance for eachof the factors between the two groups of women. Therefore, LHRHaact to decrease fibroid size via induction of a hypo-oestrogenicstate rather than by changes in the IGFs and their IGFBPs.     

Beta-catenin abnormalities and associated insulin-like growth factor overexpression are important in phyllodes tumours and fibroadenomas of the breast

The aim of this study was to assess the expression of IGF-I and IGF-II in phyllodes tumours and fibroadenomas and to see if there is any correlation between nuclear beta-catenin expression and IGF-I and IGF-II expression in these tumours. In a previous study, it has been shown that Wnt signalling is important in the pathogenesis of phyllodes tumours of the breast. Epithelial Wnt5a overexpression and stromal Wnt2 overexpression were associated with abnormal, nuclear localization of beta-catenin in the stromal cells of these tumours. However, not all tumours with beta-catenin accumulation showed Wnt overexpression. One other possible cause of beta-catenin accumulation is overexpression of insulin-like growth factors (IGFs), as both IGF-I and IGF-II have been shown to stabilize beta-catenin. In this study, 30 fibroadenomas of the breast were assessed for beta-catenin expression using immunohistochemistry and the results were compared with previous data from 119 phyllodes tumours. In situ hybridization was used to assess IGF-I and IGF-II expression in 23 phyllodes tumours and 16 fibroadenomas. Nineteen phyllodes tumours (83%) showed widespread overexpression of IGF-II and 5/23 (22%) showed widespread overexpression of IGF-I. IGF-I expression correlated with nuclear beta-catenin staining in phyllodes tumours. Malignant phyllodes tumours showed no or little IGF-I expression. There was a degree of nuclear beta-catenin expression in the stroma (weak in 33%, moderate in 27%, and strong in 40%) in all fibroadenomas and nuclear beta-catenin staining correlated with IGF-I overexpression. Extensive IGF-II overexpression was also found in the majority of fibroadenomas (12/16). These results support the hypothesis that IGF-I and IGF-II overexpression may be important in the pathogenesis of fibroepithelial neoplasms of the breast and that IGF-I overexpression is likely to be contributing to the nuclear beta-catenin localization observed in the tumours.