Exosome-transported IncRNA H19 regulates insulin-like growth factor-1 via the H19/let-7a/insulin-like growth factor-1 receptor axis in ischemic stroke

LncRNA(long non-coding RNA) H19 is a transcript of the H19 gene that is expressed during embryogenesis.We previously discove red a role for circular lncRNA H19 in the onset and prognosis of cerebral ischemic stroke.In this study,we used serum from patients with ischemic stroke,and mouse and cell culture models to elucidate the roles of plasma and neuronal exosomes in the regulatory effect of lncRNA H19 on insulin-like growth factor-1 and its mechanism in ischemic stroke,using western blotting,quantitative real-time polymerase chain reaction,and enzyme-linked immunosorbent assays.Plasma exosomal IncRNA H19 was negatively associated with blood levels of insulin-like growth factor-1 in samples from patients with cerebral ischemic stroke.In a mouse model,levels of exosomal IncRNA H19 were positively correlated with plasma and cerebral lncRNA H19.In a cell co-culture model,we confirmed that IncRNA H19 was transported from neuro ns to astrocytes by exosomes to induce downregulation of insulin-like growth factor-1 through the H19/let-7 a/insulin-like growth factor-1 receptor axis.This study provides the first evidence for the transpo rtation of IncRNA H19 by exosomes and the relationship between IncRNA H19 and insulinlike growth factor-1.

Increased hepatic expression of insulin-like growth factor-Ⅰreceptor in chronic hepatitis C

AIM： Although increased insulin-like growth factor-I receptor （IGF-IR） gene expression has been reported in hepatocellular carcinoma, studies assessing IGF-IR in chronic hepatitis C （CHC） and cirrhosis are scarce. We therefore aimed to evaluate IGF-IR and IGF-I rnRNA expression in liver from patient with CHC. METHODS： IGF-IR and IGF-I rnRNA content were determined by semi-quantitative RT-PCR and IGF-IR protein expression was determined by immunohistochemistry in hepatic tissue obtained from patients with CHC before （34 patients） and after （10 patients） therapy with interferon-α and ribavirin. RESULTS： An increase of IGF-IR rnRNA content was observed in hepatic tissue obtained from all CHC patients as well as from 6 cadaveric liver donors following orthopic transplantation （an attempt to evaluate normal livers） in comparison to normal liver, while no relevant modifications were detected in IGF-I mRNA content. The irnrnunohistochemical results showed that the raise in IGF-IR rnRNA content was related both to ductular reaction and to increased IGF-IR expression in hepatocytes. A decrease in IGF-IR rnRNA content was observed in patients who achieved sustained virological response after therapy, suggesting an improvement in hepatic damage. CONCLUSION： The up-regulation of IGF-IR expression in hepatocytes of patients with CHC could constitute an attempt to stimulate hepatocyte regeneration. Considering that liver is the organ with the highest levels of IGF-I, our finding of increased IGF-IR expression after both acute and chronic hepatic damage highlights the need for additional studies to elucidate the role of IGF-I in liver regeneration.

Tyrosine kinase of insulin-like growth factor receptor as target for novel treatment and prevention strategies of colorectal cancer

AIM： To investigate the antineoplastic potency of the novel insulin-like growth factor 1 receptor （IGF-1R） tyrosine kinase inhibitor （TKI） NVP-AEW541 in cell lines and primary cell cultures of human colorectal cancer （CRC）. METHODS： Cells of primary colorectal carcinomas were from 8 patients. Immunostaining and crystal violet staining were used for analysis of growth factor receptor protein expression and detection of cell number changes, respectively. Cytotoxicity was determined by measuring the release of the cytoplasmic enzyme lactate dehydrogenase （LDH）. The proportion of apoptotic cells was determined by quantifying the percentage of sub-G1 （hypodiploid） cells. Cell cycle status reflected by the DNA content of the nuclei was detected by flow cytometry. RESULTS： NVP-AEW541 dose-dependently inhibited the proliferation of colorectal carcinoma cell lines and primary cell cultures by inducing apoptosis and cell cycle arrest. Apoptosis was characterized by caspase-3 activation and nuclear degradation. Cell cycle was arrested at the G1/S checkpoint. The NVP-AEW541-mediated cell cycle-related signaling involved the inactivation of Akt and extracellular signal-regulated kinase （ERK） 1/2, the upregulation of the cyclin-dependent kinase inhibitors p21^waf1/CIP1 and p27^kjp1, and the downregulation of the cell cycle promoter cyclin D1. Moreover, BAX was upregulated during NVP-AEW541-induced apoptosis, whereas Bcl-2 was downregulated. Measurement of LDH release showed that the antineoplastic effect of NVP-AEW541 was not due to general cytotoxicity of the compound. However, augmented antineoplastic effects were observed in combination treatments of NVP-AEW541 with either 5-FU, or the EGFR-antibody cetuximab, or the HMG-CoA-reductase inhibitor fluvastatin. CONCLUSION： IGF-1R-TK inhibition is a promising novel approach for either monoor combination treatment strategies of colorectal carcinoma and even for CRC chemoprevention.

Expression of insulin-like growth factor Ⅱ and its receptor in hepatocellular carcinogenesis

INTRODUCTIONInsulin-like growth factor Ⅱ(IGF-Ⅱ) is a mitogenic peptide of 74 kD and is mostly synthesized in fetal liver tissue .IGF-Ⅱ is believed to play an important role in fetal growth and development and is involved in cellular proliferation and differentiation[1-5]. Recently ,several researchers have reported increased expression of the IGF-Ⅱgene in human hepatocellular carcinoma (HCC) and adjacent non-cancerous liver tissues [6-10].

Role of Insulin-like Growth Factor II Receptor in Transdifferentiation of Free Silica-induced Primary Rat Lung Fibroblasts

Objective To study the role of insulin-like growth factor II receptor in free silica-induced transdifferentiation of primary rat lung fibroblasts Methods Rat lung fibroblasts and rat alveolar macrophages were cultured. A transdifferentiation model of primary rat lung fibroblasts was induced by free silica. Levels of a-SMA protein, IGF-liR protein and mRNA were measured by immunocytochemistry, Western blot and RT-PCR, respectively. Lung fibroblasts were treated with Wortmannin. Results The expression levels of a-SMA concentration and decreased after Wortmann and IGF-IIR increased with the increasing free silica n was used. Conclusion The IGF-IIR plays an important role in free silica-induced transdifferentiation of primary rat lung fibroblasts.

SIMULTANEOUS OVER-EXPRESSION OF INSULIN-LIKE GROWTH FACTOR- Ⅱ (IGF- Ⅱ ) AND IGF- Ⅱ RECEPTOR(IGF- Ⅱ R) GENES IN HUMAN PRIMARY CANCER-IMPLICATION OF AUTOCRINE AND PARACRINE MECHANISM IN AUTONOMOUS GROWTH OF HEPATIC CANCER

This is first report about the simultaneous over-expression of both Insulin-like growth factor (IGF- I ) and its receptor (IGF- I R) at mRNA level in human primary hepatic Cancer (PHC). In 10 PHC samples from China, IGF-I and IGF- I R were both over-expressed, whereas only a background signal was detected in normal liver. In 5 pairs of PHC and its non- tumorous adjacent liver tissues from South Africa, IGF- I and IGF- I R were also over-expressed in PHC. mRNA expression of IGF- I in all 5 cases and IGF- I R in 4 of 5 cases were higher in cancer than non- tumorous adjacent liver tissues. These results strongly implicate that an autocrine and/ or paracrine mechanism might be Involved in formation and progression of PHC.

Effects of ethanol on insulin-like growth factor-Ⅰ system in primary cultured rat hepatocytes: Implications of JNK1/2 and alcoholdehydrogenase

AIM: To evaluate the effects of ethanol on the insulin- like growth factor-Ⅰ (IGF-Ⅰ) system involved in c-Jun N-terminal kinase (JNK1/2) and alcoholdehydrogenase (ADH) activity in primary cultured rat hepatocytes. METHODS: Hepatocytes isolated from male Sprague-Dawley rats were incubated with various concentrations of ethanol for different durations of time. The cells were pretreated with SP600125 (10 μmol/L) and 4-MP (200 μmol/L), and then treated with ethanol (200 mmol/L). We then measured IGF-Ⅰ secretion, IGF-Ⅰ mRNA expression, cell viability and JNK1/2 activity by radioimmunoassay, RT-PCR, MTT assay and Western blot, respectively (n = 6). RESULTS: Ethanol induced the activity of phospho (p)-JNK1/2, reaching a maximum at 60 min and then decreasing at 180 min. The effects of ethanol on the IGF-Ⅰ system were increased at 60 min (secretion: 7.11 ± 0.59 ng/mg protein vs 4.91 ± 0.51 ng/mg, mRNA expression: 150.2% ± 10.2% vs 101.5% ± 11.3%, P = 0.045) and then decreased at 180 min (secretion: 3.89 ± 0.25 ng/mg vs 5.4 ± 0.54 ng/mg protein; mRNA expression: 41.5% ± 10.4% vs 84.7% ± 12.1%, P = 0.04), however cell viability was decreased in a dose- and time-dependent manner. SP600125 blocked the ethanol-induced changes (at 60 min). Additionally, 4-methylpyrazole prevented the ethanol-induced decreases in the IGF-Ⅰ system, cell viability and p-JNK1/2 activity (at 180 min). CONCLUSION: This study suggests that ethanol- induced p-JNK1/2 activation is associated with the IGF-Ⅰ system and cell viability in hepatocytes. Furthermore, alcohol dehydrogenase is involved in the relationship between ethanol-induced inactivation of p-JNK1/2 and the changes of the IGF-Ⅰ system and cell viability.

RNA interference affects tumorigenicity and expression of insulin-like growth factor-1,insulin-like growth factor-1 receptor,and basic fibroblast growth factor-2 in rat C6 glioma cells

BACKGROUND： Human gliomas are more likely to express basic fibroblast growth factor-2 （FGF-2） insulin-like growth factor-1（IGF-1）, and IGF-1 receptor （IGF-1R） than normal brain tissue. These factors activate signal transduction systems of Ras/MAPK and PI3K/Akl, which promote glioma growth. OBJECTIVE： To utilize RNA interference （RNAi） technique to down-regulate FGF-2, IGF-1, and IGF-1R gene expression, and to investigate the effects of these genes on rat C6 glioma cells, as well as the feasibility of RNAi for treating glioma. DESIGN, TIME AND SETTING： This neurooncological, randomized, controlled, in vivo and in vitro experiment, which used RNAi methodology, was performed at the Laboratory of Molecular Biology, Institute of Biochemistry, Chinese Academy of Sciences between August 2005 and February 2008. MATERIALS： Rat C6 cell lines were purchased from Shanghai Institute of Cellular Biology Affiliated to Chinese Academy of Sciences. Small interfering RNA （siRNA） was synthesized by Shanghai GenePharma. Anti-IGF-1, anti-IGF-1R, anti-FGF-2, anti-mouse and anti-rabbit IgG G1-HRP antibodies were provided by Santa Cruz Biotechnology, USA. Four to six week-old BALB/c nude mice were purchased from the Laboratory Animal Center, Chinese Academy of Sciences. METHODS： C6 glioma cells were transfected with siRNA, which was chemically synthesized in vitro to correspond to endogenous FGF-2, IGF-1, and IGF-1R genes. The inhibition ratio of targeting mRNA expression was detected by semiquantitative RT-PCR, and protein expression was determined by Western blot analysis. C6 glioma cell proliferation was observed using a growth curve C6 glioma cell apoptosis rate and cell cycle were detected by flow cytometry. C6 glioma cell growth regression was observed by transwell migration assay. In addition, nude mouse subcutaneous tumor models were used in this study. For studying the anti-tumor effects of IGF-1 and IGF-1R siRNA, two blank control groups, with six mice each, were set up： A （2.5 μg siRNA was injected one week after C6 cells were inoculated, Le., when tumor volume reached 8 mm × 8 mm） and B （siRNA was injected at the same time with C6 cells were inoculated. To study the effects of FGF-2 siRNA, the groups consisted of a blank control group, negative control group, 2.6 μg siRNA group, 4 μg siRNA group, and 5.3 μg siRNA group, with six mice each. MAIN OUTCOME MEASURES： mRNA and protein inhibition ratio of FGF-2, IGF-1, and IGF-1 R; C6 glioma cell proliferation, apoptosis, and cycle growth arrest; C6 glioma cell growth regression and subcutaneous tumorigenicity rates. RESULTS： All siRNA constructs proved to be effective. After 48 hours, transfection of 200 nmol/L siRNA resulted in a FGF-2 or IGF-1R gene inhibition ratio 〉 80% and an IGF-1 gene inhibition ratio of approximately 70%. Protein expression levels for FGF-2, IGF-1, and IGF-1R decreased in a dose-dependent manner following siRNA transfection, with an inhibition rate 〉 85%, 60%, and 50%, respectively. C6 glioma cell proliferation and apoptosis rates increased in proportion to siRNA. The apoptosis rate of C6 glioma cells induced by FGF-2, IGF-1, and IGF-1R siRNA was 39.96%, 15.07% and 22.47%, respectively （P 〈 0.01）. Transfection of 200 nmol/L IGF or IGF-1R siRNA for 48 hours suppressed C6 glioma cell migration. At 30 days after intratumoral injection of 2.6, 4, and 5.3 tJg FGF-2 siRNA, tumor growth regression rate of FGF-2 siRNA was 56%, 67%, and 86%, respectively. The tumor growth regression rate was 71.88% and 45.71%, respectively, when IGF-1 or IGF-1R siRNA was intratumorally injected 1 week after C6 glioma cell transplantation. When IGF-1 or IGF-1 R siRNA was intratumorally injected during C6 glioma cell transplantation, the tumor growth regression rate was 78.13% and 74.29%, respectively. CONCLUSION： siRNA transfection downregulated gene expression of FGF-2, IGF-1, and IGF-1R In addition, siRNA treatment markedly suppressed glioma cell proliferation, growth, and migration, and concomitantly reduced subcutaneous tumorigenicity.

Reactivation of the insulin-like growth factor-Ⅱsignaling pathway in human hepatocellular carcinoma

Constitutive activation of the insulin-like growth factor (IGF)-signaling axis is frequently observed in human hepatocellular carcinoma(HCC).Especially the over- expression of the fetal growth factor IGF-Ⅱ,IGF-Ⅰ receptor(IGF-IR),and cytoplasmic downstream effectors such as insulin-receptor substrates(IRS)contribute to proliferation,anti-apoptosis,and invasive behavior. This review focuses on the relevant alterations in this signaling pathway and independent in vivo models that support the central role IGF-Ⅱsignaling during HCC development and progression.Since this pathway has become the center of interest as a target for potential anti-cancer therapy in many types of malignancies,various experimental strategies have been developed,including neutralizing antibodies and selective receptor kinase inhibitors,with respect to the specific and efficient reduction of oncogenic IGF-Ⅱ/IGF-IR-signaling.

Epigenetic regulation of insulin-like growth factor axis in hepatocellular carcinoma

The insulin-like growth factor(IGF) signaling path-way is an important pathway in the process of hepa-tocarcinogenesis,and the IGF network is clearly dysregulated in many cancers and developmental abnormalities.In hepatocellular carcinoma(HCC),only a minority of patients are eligible for curative treatments,such as tumor resection or liver transplant.Unfortunately,there is a high recurrence of HCC after surgical tumor removal.Recent research efforts have focused on targeting IGF axis members in an attempt to find therapeutic options for many health problems.In this review,we shed lights on the regulation of members of the IGF axis,mainly by micro RNAs in HCC.Micro RNAs in HCC attempt to halt the aberrant expression of the IGF network,and a single micro RNA can have multiple downstream targets in one or more signaling pathways.Targeting micro RNAs is a relatively new approach for identifying an efficient radical cure for HCC.

Effect of sericin on diabetic hippocampal growth hormone/insulin-like growth factor 1 axis

Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats.

Insulin-like growth factor-binding protein-3 inhibits IGF-1-induced proliferation of human hepatocellular carcinoma cells

OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like growth factor-binding protein-3(IGFBP-3)suppresses HCC cell proliferation in both IGF-dependent and independent manners.The present study is to investigate whether treatment with exogenous IGFBP-3 inhibits bF GF and PDGF production and the cell proliferation of HCC cells.METHODS Cell Counting Kit 8 assay were designed to detect HCC cell proliferation,transcription factor early growth response-1(EGR1)involving in IGFBP-3 regulation of b FGF and PDGF were detected by RT-PCR and Western blot assays.Western blot assay was adopted to detect the IGFBP-3 regulating insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS The present study demonstrates that IGFBP-3 suppressed IGF-1-induced b FGF and PDGF expression while it does not affect their expression in the absence of IGF-1.To delineate the underlying mechanism,Western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1(EGR1)is involved in IGFBP-3 regulation of b FGF and PDGF.IGFBP-3 inhibition of type 1 insulin-like growth factor receptor(IGF1R),ERK and AKT activation is IGF-1-dependent.Furthermore,transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1,b FGF and PDGF expression.CONCLUSION In conclusion,these findings suggest that IGFBP-3suppresses transcription of EGR1 and its target genes b FGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation.It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation,suggesting that IGFBP-3 could be a target for the treatment of HCC.

Effect of blocking IGF-I receptor on growth of human hepatocellular carcinoma cells

AIM： To study the expression level and localization of insulin-like growth factor -Ⅰ receptor （IGF-IR） in HepG2 cells and Chang liver cells, and to observe the effect of anti-IGF-IR monoclonal antibody （αIR3） on the growth of HepG2 cells. METHODS： The expression of IGF-IR in HepG2 cells and Chang liver cells was detected by immunohistochemistry. The influences of αIR3 on proliferation and apoptosis were examined by the 3- （4, 5-dimethylthiazol-2-yl）-2, 5- diphenyltetrazolium bromide （MTT） assay and electron microscopy, respectively. Flow cytometry （FCM） was applied for the analysis of cell cycle and apoptosis was observed under electron microscope. RESULTS： IGF-IR was located in the membranes of both HepG2 and Chang liver cell lines, and the expression level of IGF-IR was higher in HepG2 cells than in Chang liver cells. Treated with 0.1 μg/mL αIR3 for 48 h in vitro, the cell growth index （GI） of HepG2 cells was significantly higher than that of control （103.41% ys 100%, P 〈 0.01）. However, the αIR3 for 24 h at final concentration of 4.0 μg/mL made the GI of HepG2 cells lower than that of control （93.37% vs 100%, P 〈 0.01）. Compared with control, treated with αIR3 for 48 h at final concentrations ranging from 2.0 μg/mL to 4.0 μg/mL markedly reduced the GIs of HepG2 cells （97.63%, 97.16%, 95.13%, 92.53% vs 100%, P 〈 0.05 or P 〈 0.01）, treated with αIR3 for 72 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL decreased the GIs of HepG2 cells obviously （95%, 91.63%, 90.77%, 89.84%, 88.51% vs 100%, P 〈 0.01）, and treated with αIR3 for 96 h at final concentrations ranging from 0.5 μg/mL to 4.0 μg/mL made GIs of HepG2 cells lower significantly （88.86%, 83.97%, 79.81%, 77.24%, 70.51% vs 100%, P 〈 0.05or P 〈 0.01）. Moreover, treated with αIR3 from 24 h to 96 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL reduced the GI of HepG2 cells from 97.63% to 70.51% in a dose- and time-dependent manner. Also, αIR3 treatment for 72 h at final concentration from 0.5 μg/mL to 2.0 μg/mL increased the proportion of G0/G1 phase cells（61.73%, 67.1%, 83.7%,76.87% vs 44.47%, P 〈 0.01） and significantly decreased that of S phase cells（28.63%, 25.13%, 15.63%, 23.13% vs 53.17%, P 〈 0.01）, in contrast to the proportion of G2/M phase cells. The apoptotic rates of HepG2 cells were increased more than that of control （7.83%, 16.13%, 21.1%, 37.73% vs 4.13%, P 〈 0.01）. CONCLUSION： The malignant cell phenotype of human hepatocarcinoma cell is related to overexpression of IGF- IR. The blockage of IGF-IR with αIR3 may contribute to the inhibition of proliferation and induction of apoptosis in HepG2 cells.

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors and CSF-Ⅰ receptors in human primary hepatocellular carcinoma and juxtacancerous liver tissue

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors(IGF-Ⅱ-R)and CSF-Ⅰ re-ceptors(CSF-Ⅰ-R)was observed in 17 cases of human primary hepatocellular carcinoma(PHC)and the juxtacancerous liver tissue with immunohistochemistry(ABC),Western blot and North-ern blot technique,It was found that the expression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-Ⅰ-R was signif-icantly higher in PHC than in normal liver tissue and the expression of IGF-Ⅱ and IGF-Ⅱ-R wasremarkably higher in the juxtacancerous liver tissue from PHC patients than in PHC proper.Itwas noteworthy that the expression of IGF-Ⅱ in both the cancer proper and the juxtacancerousliver tissue was characterized by its fetal type.Besides,the expression of CSF-Ⅰ-R was signifi-cantly higher in PHC than in the juxtacancerous liver tissue.It is believed that the abnormal ex-pression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-I-R in PHC and the juxtacaneerous liver tissue might berelated to the autocrine mechanism of human PHC.

Relationship between Insuline-like Growth Factor-I and Progesterone Secretion of Cultured Human Trophoblast Cells in Vitro

Objective To investigate the effect of insuline-like growth factor-Ⅰ （IGF-Ⅰ） on progesterone genesis and regulation. Methods Cytotrophoblast cells were collected by trypsin-collagenase digestion and percoll gradient centrifugation for primary culture. After stimulated with different concentrations（100 μg/ml, 10 μg/ml, 1 μg/ml, 0.1 μg/ml） of IGF-Ⅰ at the same time and with different duration（12 h,24 h,48 h, 72 h） of IGF-Ⅰ with the same concentration, progesterone levels in the media were measured by radioimmunoassay. Simultaneously, semiquantitative reverse transcriptase polymerase chain reaction （RT-PCR） was applied to determine the expression of low density lipoprotein receptor （LDLR） mRNA. Results Progesterone levels correlated positively with IGF-Ⅰ along with the IGF-Ⅰ concentration increasing, progesterone level began to increase at 12 h, and reached the climax at 48 h when cultured with 100 μg/L IGF-Ⅰ. The expression of LDLR mRNA was detectable in every group and accordant with variation of progesterone level. Conclusion Progesterone secretion has time- and dose-dependent effect on IGF-Ⅰ, and IGF-1 can up-regulate the expression of LDLR mRNA. IGF-Ⅰ may play an important role in promoting secretion of progesterone in trophoblast cells.

日本七鳃鳗转化生长因子βⅠ型受体基因(L-Tgfbr1)的克隆与表达分析

作为无颌类脊椎动物的现存代表之一,日本七鳃鳗(Lampetrajaponica)是研究免疫系统起源与进化的重要模型。为了探究TGF-β(Transforming growth factor beta)信号通路在日本七鳃鳗免疫调节中的功能,本研究利用PCR技术克隆了日本七鳃鳗TGF-βⅠ型受体基因(L-Tgfbr1)的编码序列,开放阅读框长度为1335 bp,编码444个氨基酸残基。L-Tgfbr1蛋白含有已知的TGF-βⅠ型受体分子的主要功能结构域,其中位于胞内的丝/苏氨酸激酶催化结构域保守性较高。系统进化树分析表明,L-Tgfbr1处于脊椎动物Tgfbr1蛋白的底端进化枝上,表明其在Tgfbr1进化史中具有原始性地位。实时定量PCR结果发现,L-Tgfbr1在心脏等组织中的转录水平较高。利用脂多糖注入七鳃鳗激活其先天性免疫应答,L-Tgfbr1在肾脏、鳃、髓小体、肝脏、白细胞、口腔腺中的转录水平呈现一过性的迅速上调。利用免疫印迹进一步验证了脂多糖免疫24 h时后L-Tgfbr1在白细胞中的蛋白表达水平显著上调。利用免疫荧光染色发现L-Tgfbr1蛋白主要分布于七鳃鳗白细胞和髓小体细胞的细胞质中。以上结果表明L-Tgfbr1及其介导的TGF-β通路可能在七鳃鳗免疫调控中发挥重要功能。

肝癌和癌旁肝组织中IGF-Ⅰ,IGF-Ⅰ受体mRNA的表达

目的 探讨胰岛素样生长因子Ⅰ（ＩＧＦⅠ） 及其受体（ＩＧＦⅠＲ）在肝细胞癌变过程中的作用及意义．方法 采用ＤＮＡＲＮＡ 原位杂交方法观察肝癌（ ｎ ＝ ３０） 和癌旁肝组织中ＩＧＦⅠ，ＩＧＦⅠ受体ｍ ＲＮＡ 的表达．结果 在肝癌和癌旁肝组织中ＩＧＦⅠ的表达率分别为４０－０ ％和５０－０ ％ ，ＩＧＦⅠ受体的表达率分别为４６－７ ％ 和５３－３ ％ ；ＩＧＦⅠ，ＩＧＦⅠ受体在分化较差的癌细胞和不典型增生肝细胞中表达最为明显．结论 ＩＧＦⅠ和ＩＧＦⅠ受体可能在肝细胞癌变过程中发挥重要作用．

RNA干扰沉默IGF-Ⅰ R表达对非小细胞肺癌细胞生物学特性及化疗敏感性的影响

目的:评价RNA干扰(RNA interference,RNAi)技术,对人肺癌A549细胞系中胰岛素样生长因子类受体(IGF-Ⅰ R)表达的阻断效应,和IGF-Ⅰ R基因沉默后细胞增殖、凋亡等生物学特性及肿瘤细胞对化疗药物敏感性的改变。方法:应用U6启动子,介导DNA模板转录生成短发夹样RNA(shRNA),并转染人肺癌A549细胞株,从而产生IGF-Ⅰ R特异性小干扰RNA(siRNA),经RT-PCR和Western blot检测IGF-Ⅰ R表达的改变;联合应用化疗药物顺铂(DDP),通过MTT法和流式细胞技术等,观察细胞生长、细胞周期、细胞凋亡及DDP半数致死量(IC50)的变化。结果:IGF-Ⅰ R表达水平明显下降(抑制率高达89.8%),肿瘤细胞增殖能力明显减弱,细胞滞留于G0期的比例上升;DDP对肿瘤细胞24h、48h、72h的IC50均明显减少,IGF-Ⅰ R siRNA1组DDP作用72h的IC50为0.92 mg/L,明显低于control-siRNA组的3.77mg/L,0.5mg/L DDP联合IGF-Ⅰ R siRNA1作用48h后,A549细胞的生长抑制率达32.1%,明显高于control-siRNA组的18.9%,细胞凋亡率从27.8%上升至44.2%。结论:运用RNAi技术能有效抑制A549细胞IGF-Ⅰ R的表达,使细胞增殖能力减弱,化疗敏感性增加。

草原红牛胰岛素样生长因子Ⅰ受体基因3′UTR序列多态性分析

以58头草原红牛为试验材料,采用PCR-SSCP技术对胰岛素样生长因子Ⅰ受体(IGF-ⅠR)基因3′UTR序列多态性进行了检测。结果表明,在IGF-ⅠR基因3′UTR中发现PCR-SSCP的多态位点,有2种等位基因和3种基因型。对所得基因型与生长和胴体性状的相关性分析结果发现,在3′UTR中AB型的胴体产肉率、肉骨比显著高于AA、BB型(P<0.05);AA型的脂肪覆盖率显著高于BB型(P<0.05),与AB型差异不显著(P>0.05)。

胰岛素样生长因子Ⅰ、胰岛素样生长因子Ⅰ受体在大肠癌中的表达及其意义

目的检测胰岛素样生长因子Ⅰ(IGF-Ⅰ)、胰岛素样生长因子Ⅰ受体(IGF-ⅠR)蛋白在大肠癌中的表达,并分析与临床病理学因素的关系,探讨两者在大肠癌发病机制中的相互作用及与患者预后的关系。方法选取不同类型的大肠癌组织48例(试验组),其中男性25例,女性23例;年龄34～78岁,平均年龄53岁。任意选癌旁5cm以上的正常组织24例(正常对照组)。采用SABC法检测IGF-Ⅰ、IGF-ⅠR的表达。结果在48例大肠癌组织中,IGF-Ⅰ、IGF-ⅠR的阳性表达率分别为64.58%、58.33%,均显著高于癌旁正常组织中的16.67%、16.67%。IGF-Ⅰ、IGF-ⅠR在大肠癌组织中的表达与肿瘤的浸润程度、淋巴结转移、Dukes’分期有关,而与其他的病理因素及患者5年生存情况无关。IGF-Ⅰ和IGF-ⅠR在大肠癌组织中的表达呈明显相关性。结论IGF-Ⅰ、IGF-ⅠR可能相互协同作用参与大肠癌的浸润、转移,可作为反映大肠癌进展的重要生物学指标,但IGF-Ⅰ、IGF-ⅠR阳性表达与大肠癌患者的预后无明显相关性。