Gene transfer of a β2-adrenergic receptor kinase inhibitor up-regulates the level of β2-adrenergic receptor and cAMP in the asthmatic murine lung

Objective: To investigate the effects of gene transfer of a β-adrenergic receptor(β-AR) kinase inhibitor(β ARKct)on pulmonary β2-adrenergic receptor and cAMP following β2-AR agonist treatment in asthmatic mice, and to analyze the relationship between the routes of gene delivery and the changes of β2AR and cAMP. Methods: BALB/c mice were sensitized and challenged by ovalbumin to establish the asthmatic model treated with βAR agonist ( salbutamol injected intramuscularly). The plasmid with the expression of βARKct was constructed and βARKct gene transfer was performed through intravenous injection or intratracheal instillation in asthmatic mice.The gene expression was measured with Western blot analysis, and the changes of pulmonary β-AR and cAMP evaluated by Radioimmunoassay. Results: The expression of tranfered βARKct gene was detectable in lungs and it was expressed more in the lungs of the mice receiving intratracheally plasmid than those receiving intravenously. The levels of βAR and cAMP were upregulated after using plasmid-βARKct to the asthmatic mice treated with β AR agonist. Conclusion: Our results indicated that there were down-regulation of βAR and cAMP in asthmatic mice treated with βAR agonist. Gene transfer of βARKct could inhibit the extent of the down-regulation of βAR and cAMP. The route of gene delivery could also affect the degree of up-regulation of βAR and cAMP. Gene transfer βARKct may provide a novel approach to the therapeutic strategy for asthma.     

Inhibition of allergic responsiveness in a murine asthma model via IFN-γ transgene expression

Objective To investigate adenoviral vector mediated exogenous gene expression in mouse lungs and the effect of mIFN-γ transgene expression on allergen-induced pulmonary eosinophil infiltration in a murine asthmatic model. Methods LacZ marker gene was transduced into CD-1 mouse airway epithelial cells by installation of a replication-deficient adenovirus with LacZ gene (AdCMVLacZ) 5×10[9]plaque forming unit (pfu) in the intratrachea or nostril.C57 mice were sensitized intraperitoneally and challenged by aerosol with ovalbumin (OVA) to produce an asthmatic model.AdCMVmIFNγ 5×10[9] pfu was administered via nostril in asthmatic mice 48 h before OVA challenge.Sera, bronchial alveolar lavage (BAL) and lungs were recovered 48 h after OVA challenge.Results After administration with AdCMVLacZ by intratracheal installation or nose-drop, the lungs revealed a high level of widespread LacZ transduction with X-gal staining, mainly along airways.IFN-γ via adenoviral vector transduction could be overexpressed both in vitro and in vivo (1624.7±1321.5 pg/ml in BAL 96 h after AdCMVIFNγ infection).In AdCMVIFNγ treated asthmatic models, histological evaluation revealed marked suppression of eosinophil peribronchial and perivascular infiltration; the recoverable percentage of eosinophils in BAL was an average of 9.00%±4.58%, which was a statistically significant decrease versus that of the positive control group (75.13%±6.85%) (P<0.001).The total cell number in BAL ((145±55.6)×10[3 cells/ml) in AdCMVmIFNγ treated mice also was tremendously reduced compared to the positive control group ((216.6±71.1)×10[3 ]cells/ml).Conclusions Adenoviral vector was able to overexpress exogenous gene in murine lungs.IFN-γ overexpression via adenoviral vector in pulmonary epithelia in vivo can abrogate allergen-induced eosinophilic infiltration in lungs in an asthmatic model, which may suggest a new preventively therapeutic method for cytokine immunogenetic transfer in allergic asthma.     

Relationship between Trp64Arg mutation in the β3-adrenergic receptor gene and metabolic syndrome: a seven-year follow-up study

Background It has been shown that the β3-adrenergic receptor （β3-AR） gene Trp64Arg mutation was closely related to obesity and insulin resistance, and may be related to the prevalence of metabolic syndrome （MS）. The aim of this study was to investigate the relationship between the 33-AR gene mutation and the prevalence of MS. Methods A seven-year follow-up study was initiated in 2000, with 496 samples of simplex obese subjects （body mass index ≥25 kg/m2） and 248 normal-weight subjects. According to the β3-AR genotypes, the subjects were classified as Trp64 homozygote group and Arg64 carrier group and after 7 years the prevalence of MS was determined. Results According to the baseline profile, there were no significant differences in the adiposity, blood pressure, lipid profile, fasting plasma glucose and fasting insulin between Trp64 homozygote group and Arg64 carrier group either in obesity or normal-weight subjects. The results of follow-up study indicated that in obese men the prevalence rate of MS was much higher in Arg64 carrier group than that in Trp64 homozygote group （54.76% vs. 40.85%, P 〈0.05）, but there was no statistical difference in women of the above groups. The prevalence rate of MS in obese men of both Trp64 homozygote group and Arg64 carrier obese group were obviously higher than that in women of the above groups （40.85% vs. 18.27% and 54.76% vs 21.28%, all P 〈0.005）. Differences were not statistically significant in the prevalence of MS for normal weight Trp64 homozygote group and normal weight Arg64 carrier group, either between men, between women, or between men and women. Comparison of populations indicated that no matter with the β3-AR gene mutation or not, the prevalence of MS in obese subjects was significantly higher than normal weight subjects （X2=28.240 and x2=15.586, all P 〈0.005）. Logistic analysis showed that the mutation of β3-AR gene was associated with the prevalence of MS in men.     

Effects of metoprolol on β1 adrenergic receptor polymorphism and receptor density in urban Chinese patients with heart failure

β-blockers have been recommended as a standard treatment for patients with mild to moderate systolic chronic heart failure （CHF） because they not only relieve patients＇ symptoms but also decrease mortality. However, β-blockers have a variety of effects on different CHF patients. Among them, β1-adrenergic receptor （AR） gene polymorphism is probably a significant one. The purpose of this study was to investigate the effects of metoprolol on cardiac function, cardiac geometrical size and density of β1-AR of CHF patients as well as the association between two common single nucleotide polymorphisms （SNPs） of β1-AR（Gly389Arg and Ser49Gly） and the effects of metoprolol.     

Primary study on correlation between β2-adrenoceptor haplotypes and asthma in children of Han nationality in Chongqing

Objective: To investigate the correlation between β2-adrenergic receptors (β2-AR) haplotypes and asthma of Hah nationality children in Chongqing region. Methods: PCR and restriction fragment analysis were used to study 16, 27loci of the β2-AR polymorphism in 76 unrelated asthmatic children and in 100 healthy children and adults of Han nationality as control. A statistical analysis of the correlation between glycine (Gly)16 allele, Gly16/glutamine (Gln)27 haplotype and asthmatic clinical status was carried out. Results: There was no significant increase of the frequency of Gly16 and Gln27 allele in the asthmatic group as compared with the control group (P＞0.05). There was a significant increase of the frequency of Gly16 allele and Gly16/Gln27 haplotype in severe asthmatic cases than in the mild and moderate asthmatic ones (P＜0.01, 0.05). Conclusion: It is considered that asthma is not caused by Gly and Gln alleles ofβ2-AR polymorphisms. Glyl6 allele and Gly16/Gln27 haplotype are possibly correlated with the severity of the clinical manifestations in the children of Han nationality in Chongqing.     

Genetic Variation in β3-Adrenergic Receptor and Obesity, Type 2 Diabetes, Insulin Resistance in Chinese Pedigrees

Objective: To explore the association between the polymorphism of the β3-adrenergic receptor(β3-AR )gene and obesity, type 2 diabetes, insulin resistance in Chinese pedigrees. Methods: Eight pedigrees with obesity and type 2 diabetes have been detected with the technique of PCR-RFLP in codon 64 of the exon region representing the variation Trp64 Arg of β3-AR gene. Results: In pedigree linkage analysis, the maximal LOD score of β3-AR gene with obesity was 3.385109 (θ=0.000000) at the mode of autosomal dominant in pedigree 3. The maximal LOD score of β3-AR with type 2 diabetes was 0.222336 (θ=0.000000) at the mode of autosomal dominant in pedigree 2 and 0.805003(θ=0.000000) at the mode of autosomal recessive in pedigree 4. Conclusion: The results indicate that ① The Trp 64 Arg variation have a cause effect significances of some familial obesity. Pedigree linkage analysis can powerfully help to understand the action mechanism of the candidate genes, ②Better comphrehension the workings of adrenergic receptors should provide a new understanding of obesity, type 2 diabetes and insulin resistance and perhaps lead to new methods of treatment.     

Effect of β3-adrenergic agonists on alveolar fluid clearance in hypoxic rat lungs

Background Recent research suggests that β2-adrenergic agonists increase alveolar fluid clearance （AFC） under physiologic and pathologic conditions. It is unknown whether β3-adrenergic agonists also increase AFC under pathologic conditions. The aim of this study was to investigate the effect of β3-adrenergic agonists on AFC following hypoxic lung injury and the mechanisms involved. Methods Hypoxic rats were exposed to 10% oxygen. BRL-37344 （133-adrenergic agonist） or CGP-12177 （selective β3-adrenergic agonist） alone or combined with β receptor antagonists, sodium channel blockers, or Na＋/＋~-ATPase blockers were perfused into the alveolar space of rats exposed to 10% oxygen for 48 hours. Total lung water content （TLW） and AFC were measured. Results AFC did not change for the first 24 hours but then decreased after 48-hour exposure to 10% oxygen. The perfusion of BRL-37344 or CGP-12177 significantly increased AFC in normal and hypoxic rats. The AFC-stimulating effect of CGP-12177 was lowered with amiloride （a Na＋ channel blocker） and ouabain （a Na~/K~-ATPase inhibitor） by 37% and 49%, respectively. Colchicine significantly inhibited the effect of CGP-12177. Conclusions These findings suggest that β3-adrenergic agonists can increase AFC during hypoxic lung injury in rats and accelerate the amelioration of pulmonary edema.     

Effects of Aging and Advanced Glycation on Gene Expression in Cerebrum and Spleen of Mice

Objective To analyze the effects of aging or advanced glycation on gene expression in the cerebrum and spleen of female C57BL/6J mice. Methods The gene expression profile was determined by using cDNA expression arrays containing 588 cDNA. Results Aging and advanced glycation resulted in differential gene expression patterns of cerebrum and spleen compared with young mice. Among the 80 genes detected in cerebrum, 43 exhibited a change in mRNA ratios with aging or treatment. Thirty-four changes (79%) were common in aged and D-galactose treated mice, whereas the cerebrum from aged and AGE-lysine treated mice showed common changes in expression of 38 genes (88%). Of the 86 genes detected in spleen, 29 (34%) displayed an age-related decrease in expression, whereas 3 (3%) displayed an increase in expression levels with aging. Eighteen genes from the detectable genes exhibited expression changes in both cerebrum and spleen of mice. Conclusions The gene expression profiles of D-galactose and AGE-lysine treated     

Relationship between β3-AR Gene and Obesity, Type 2 Diabetes, Insulin Resistance in Chinese Han Population

Objective: To explore the relationship between the β3-adrenergic receptor(β3-AR)gene and obesity, T2DM. insulin resistance in Chinese Han population. Methods: Fifty-three healthy subjects, 105 subjects with simple obesity, 63 type 2 diabetic patients without obesity, and 114 type 2 diabetic patients with obesity were studied with the technique of PCR-RFLP in codon 64 of the exon region of β3-AR gene representing the variation Trp/Arg. Results:Compared with the subjects of Trp homozygous group, the individuals with Arg allele were more elevated in WHR,MBP,SBP,DBP,FBS,PBS, FINS,PINS, FCP,PCP and lower in ISI. Frequency of Arg allele was higher in HINS sub-group without T2DM. Cnclusion: The results indicate that the Trp/Arg variation might lead to insulin resistance, obesity and T2DM.β3-AR gene is supposed to be the candidate gene of insulin resistance, obesity and T2DM in ChineseHan population.     

Down-regulation of β-catenin Nuclear Localization by Aspirin Correlates with Growth Inhibition of Jurkat Cell Line

In this study, we examined the effects of aspirin on the growth rates, subcellar distribution of β-catenin protein, the expression of β-catenin/TCF signaling pathway target gene cyclinD1 mRNA, and cell cycle of Jurkat cell line （Human T-acute lymphoblastic leukemia）. Our results showed that the treatment with aspirin inhibited the growth of Jurkat cell line. Jurkat cells treated with 3 mmol/L of aspirin could significantly decrease nuclear localization of β-catenin, and at 5 mmol/L of aspirin, the nuclear localization of β-catenin was undetectable. QRT-PCR showed that the target gene cyclinDl mRNA expression was gradually decreased with the dosage of aspirin. Aspirin induced G0/G1 cell cycle arrest in Jurkat cells. We are led to conclude that aspirin acts through β-catenin-independent mechanisms. The effects of aspirin include down-regulation of β-catenin nuclear localization and G0/G1 cell cycle arrest, which might serve as a means of growth inhibition in aspirin-treated human Jurkat cell line.     

The expression of CD40 and CD40L on the surface of peripheral blood mononuclear cells in asthmatic rats and the effect of anti-CD40L McAb on Th1 and Th2 cytokines

Objective： To investigate the expression of CD40 and CD40 ligand （CD4OL） on the surface of peripheral blood mononuclear cells（PBMCs） in asthmatic rats and the effect of anti-CD40L McAb on cytokines of PBMCs. Methods： Flow cytometry and RT-PCR were used to detect the expression of CD40 and CD40L of PBMCs in asthmatic rats. After the PBMCs was treated with anti-CD40L McAb, ELISA was used to detect the IL-4 and IFN-γ levels of culture supernatants. Results： Compared with the normal control group, the expression of CD40 and CD40L of PBMCs in asthmatic rats increased （P 〈 0.05）. Compared with the untreated group, the level of IL-γ and the ratio of IL-4/IFN-γ decreased after the PBMCs was treated with anti-CD40L McAb（P 〈 0.05）. Conclusion： The expression of CD40 and CD40L on the surface of PBMCs in asthmatic rats was up-regulated. Anti-CD40L McAb can rectify the imbalance of Th1 and Th2 cytokines.     

Effect of Target-directed Regulation of Uncoupling Protein-2 Gene Expression on Ischemia-reperfusion Injury of Hepatocytes

The effect of target-directed regulation of the uncoupling protein-2 （UCP-2） gene expression on the ischemia-reperfusion injury of hepatocytes under different conditions was investigated. The expression plasmid and RNAi plasmid targeting UCP-2 gene were constructed and trans- fected into normal hepatocytes and fatty liver cells, respectively. The expression of UCP-2 mRNA was detected by real time PCR. The cells were divided into normal cell group （NCG）, group of normal cells transfected with empty vector （EVNCG）, group of normal cells transfected with expression plasmid （EPNCG）, fatty liver cell group （FCG） and group of fatty liver cells transfected with RNAi plasmid （RPFCG）. The ischemia-reperfusion model in vitro was established. One, 6, 12 and 24 h after reperfusion, Annexin V/PI flow cytometry was used to measure cell necrosis rate, apoptosis rate and survival rate. Simultaneously, the intracellular ATP, ROS and MDA levels were determined. The re- sults showed that 1, 6, 12 and 24 h after ischemia-reperfusion, the intracellular ROS, MDA and ATP levels and cell survival rate in EPNCG were significantly lower, and cell necrosis rate significantly higher than in NCG and EVNCG, but there was no significant difference in apoptosis rate among NCG, EVNCG and EPNCG （P〉005）. Six, 12 and 24 h after reperfusion there was no significant dif- ference in ROS, MDA levels and apoptosis rate between FCG and RPFCG （P〉0.05）, but the ATP level and survival rate of cells in RPFCG were higher than in FCG （P〈0.05）. It was concluded that down-regulation of the UCP-2 gene expression in steatotic hepatocytes could alleviate the ische- mia-reperfusion injury of liver cells.     

Ultrasound-mediated microbubble delivery of pigment epithelium-derived factor gene into retina inhibits choroidal neovascularization

Background Many studies have suggested that the imbalance of angiogenic factor and anti-angiogenic factor expression contributes significantly to the development of choroidal neovascularization （CNV）, and ultrasound microbubble combination system can increase the gene transfection efficiency successfully. This study was designed to investigate whether ultrasound-mediated microbubble destruction could effectively deliver therapeutic plasmid into the retina of rat, and whether gene transfer of pigment epithelium-derived factor （PEDF） could inhibit CNV.
Methods Human retinal pigment epithelial cells were isolated and treated either with ultrasound or plasmid alone, or with a combination of plasmid, ultrasound and microbubbles to approach feasibility of microbubble-enhanced ultrasound enhance PEDFgene expression; For in vivo animal studies, CNV was induced by argon lasgon laser in rats. These rats were randomly assigned to five groups and were treated by infusing microbubbles attached with the naked plasmid DNA of PEDF into the vitreous of rats followed by immediate ultrasound exposure （intravitreal injection）; infusing liposomes with the naked plasmid DNA of PEDF into the vitreous （lipofectamine ＋ PEDF）; infusing microbubbles attached with PEDF into the orbit of rats with ultrasound irradiation immediately （retrobular injection）; infusing microbubbles attached with PEDF into the femoral vein of rats with exposed to ultrasound immediately （vein injection）. The CNV rats without any treatment served as control. Rats were sacrificed and eyes were enucleated at 7, 14, and 28 days after treatment. Gene and protein expression of PEDF was detected by quantitative real-time RT-PCR, Western blotting and immunofluorescence staining, respectively. The effect of PEDF gene transfer on CNV was examined by fluorescein fundus angiography.
Results In vitro cell experiments showed that microbubbles with ultrasound irradiation could significantly enhance PEDF delivery as compared with microbubbles or ultrasound alone. In the rat CNV model, transfection efficiency mediated by ultrasound/microbubbles was significantly higher than that by lipofectamine-mediated gene transfer at 28 days after treatment. The study also showed that with the administration of ultrasound-mediated microbubbles destruction, the CNV of rats was inhibited effectively.
Conclusions Ultrasound-microbubble technique could increase PEDF gene transfer into rats＇ retina and chorioid, in association with a significant inhibition of the development of CNV, suggesting that this noninvasive gene transfer method may provide a useful tool for clinical gene therapy.     

Effects of Mitofusin-2 Gene on Cell Proliferation and Chemotherapy Sensitivity of MCF-7

In order to evaluate the effect of mitofusin-2 gene （mfn2） on proliferation and chemotherapy sensitivity of human breast carcinoma cell line MCF-7 in vitro, pEGFPmfn2 plasmid carrying full length of mitofusin-2 gene was transfected, by using sofast, into MCF-7 cells. Mitofusin-2 gene expression in MCF-7 cells transfected by sofast after 48 h was detected by PCR and Western blotting, and the stable expression of GFP protein in MCF-7 cells by Western blot analysis. The proliferation of MCF-7 cells was assayed by MTT and cell counting. By using PI method, the effects of mfn2 on the cell cycle distribution of MCF-7 were measured. Annexin-Ⅴ/PI double labeling method was employed to detect the changes in apoptosis induced by chemotherapeutics before and after transfection. The results showed that the MCF-7 cells transfected with mfn2 gene could stably and highly express GFP protein. MTT assay revealed that after transfection of mfn2 cDNA, the proliferation of MCF-7 cells was significantly inhibited. DNA histogram showed that cells arrested in S phase, and the percentage of S phase cells was 42.7, 17.2 and 19.6 in mfn2 cDNA transfection group, blank plasmid transfection group and blank control group, respectively （P〈0.05）. The apoptosis ratio of the cells transfected with mfn2 gene was increased from 3.56% to 15.95%, that of the cells treated with camptothecin （CAMP） followed by mfn2 gene transfection was 69.6%, and that in blank plasmid transfection group and blank control group was 31.0% and 23.4% respectively （P〈0.05）. It was suggested that transfection of mfn2 gene could significantly inhibit the proliferation of MCF-7 cells and promote their sensitivity to CAMP with a synergic effect.     

Non-Fusion and Fusion Expression of β-Galactosidase from Lactobacillus bulgaricus in Lactococcus lactis

Objective To construct four recombinant Lactococcus lactis strains exhibiting high β-galactosidase activity in fusion or non-fusion ways, and to study the influence factors for their protein expression and secretion. Methods The gene fragments encoding β-galactosidase from two strains of Loctobacillus bulgaricus, wch9901 isolated from yogurt and 1.1480 purchased from the Chinese Academy of Sciences, were amplified and inserted into lactococcal expression vector pMG36e. For fusion expression, the open reading frame of the β-galactosidase gene was amplified, while for non-fusion expression, the open reading frame of the β-galactosidase gene was amplified with its native Shine-Dalgarno sequence upstream. The start codon of the β-galactosidase gene partially overlapped with the stop codon of vector origin open reading frame. Then, the recombinant plasmids were transformed into Escherichia coli DH5α and Lactococcus lactis subsp, lactis MG1363 and confirmed by determining β-galactosidase activities. Results The non-fusion expression plasmids showed a significantly higher β-galactosidase activity in transformed strains than the fusion expression plasmids. The highest enzyme activity was observed in Lactococcus lactis transformed with the non-fusion expression plasmids which were inserted into the β-galactosidase gene from Lactobacillus bulgaricus wch9901. The β-galactosidase activity was 2.75 times as high as that of the native counterpart. In addition, β-galactosidase expressed by recombinant plasmids in Lactococcus lactis could be secreted into the culture medium. The highest secretion rate （27.1%） was observed when the culture medium contained 20 g/L of lactose. Conclusion Different properties of the native bacteria may have some effects on the protein expression of recombinant plasmids. Non-fusion expression shows a higher enzyme activity in host bacteria. There may be a host-related weak secretion signal peptide gene within the structure gene of Lb. bulgaricus β-galactosidase, and its translation pr     

Role of β-Adrenergic Signal Transduction Pathway on Myocardial Ischemic Preconditioning of Rats

To study the changes in every part of the β-adrenergic signal transduction pathway and their effects on ischemic preconditioning of rat myocardium in vivo. SD rats were divided into three groups： IP group, I/R group and CON group. The IP group was further divided into PC1-, 2-, 3-, and PC1＋, 2＋, 3＋ groups according to preconditioning procedure. The rats received surgical procedure and underwent left coronary artery occlusion and reperfusion. We analyzed the infarct size by TTC staining, measured serum myocardial enzymes, studied the β-AR Bmax and Kd by radioligand binding assay of receptors, checked the activity of AC and PKA by the method of biochemistry and examined the content of cAMP by radioimmunoassay. The infarct area was much smaller in the IP group than in the I/R group （P〈0. 001）, while the enzymes were significantly higher in I/R （P〈0. 001）. The Bmax of β-AR in IP was much higher than that in I/R （P〈0. 001）, but no difference in Kd could be seen between IP and I/R groups. In IP, the activity of AC and PKA and the content of cAMP were higher than those in I/R （P〈0.05, 0. 002 and 0. 001, respectively）. In the procedure of preconditioning, the content of cAMP and the activity of PKA showed the characteristic of cyclic fluctuation. Ischemic preconditioning can protect the heart from necrosis and reduce endo-enzyme leakage. The system of β-adrenergic signal transduction pathway probably takes part in the protection effect of the IP, which might be elicited by the PKA .     

Association of E-cadherin and β-catenin with metastasis in nasopharyngeal carcinoma

Background This study was designed to detect methylation of E-cadherin gene promoter and gene mutation of β-catenin in exon 3 and their expression of protein and mRNA in primary tumor and lymph node metastatic tumor of nasopharyngeal carcinoma (NPC), and investigate the mechanism of invasion and metastasis of neoplastic cells in NPC. Methods Fourty-two fresh biopsy samples were taken from untreated NPC patients at the Affiliated Hospital of Sun Yat-sen Medical College, Sun Yat-sen University, Guangzhou, China during the period of 1999 -2002. Among them 21 were taken from primary tumors and the other 21 from lymph node metastatic tumors. The gene promoter methylation of E-cadherin was detected by methylation-specific PCR (MSP). The mutation in exon 3 of β-catenin was detected by direct sequencing analysis. RT-PCR, Western blot and immunohistochemical staining were used to detect the mRNA and protein expression patterns in both primary and metastatic tumors of NPC. Results Down-regulated expression of E-cadherin in metastatic tumor was compared with that in primary tumor. Reduced expression of E-cadherin was found to be correlated with lymph node metastatic tumor of NPC ( P = 0. 004) ; but there was no obvious correlation between primary and metastatic tumors in the expression of β-catenin (P = 0. 698). The mRNA expression level of Ecadherin in metastatic tumors decreased significantly compared with that in primary tumors. However, little change was observed in the mRNA level of β-catenin in different tumor tissues. Only 4 samples (19. 1%) displayed gene promoter methylation of E-cadherin in primary tumor and 10 samples (47. 6%) showed methylated form of E-cadherin. The gene promoter methylation of E-cadherin was more common in metastatic tumor than in primary tumor of NPC ( P =0. 024). Only 2 (4. 76% ) of the 42 samples showed mutations in exon 3 of β-catenin at 41 (T41A, ACC→GCC) and codon 47(S47T, AGT→ACT). The cytoplasmic and nuclear expression of β-catenin in tumor was not found in any samples of NPC. Conclusions The results suggest that the downregulation of E-cadherin results from the gene promoter aberrant methylation of E-cadherin and that the methylation of E-cadherin plays an important role in invasion and metastasis of tumor cells in NPC. However, β-catenin mutation is an infrequent event in NPC, and β-catenin is not a critical factor influencing the invasion and metastasis of tumor cells in NPC.     

β2-ADRENERGIC RECEPTOR GENE POLYMORPHISM IN CHINESE NORTHERN ASTHMATICS

Objective To investigate whether the polymorphisms of β2-adrenergic receptor (β2-AR) at position 16, 27, 164 are associated with asthma in Northern Chinese subjects.Methods Genomic DNA was collected from unrelated Northern Chinese population of Han ethnicity, including 125 unrelated asthmatic individuals and 96 healthy controls. β2-AR genes at position 16, 27, 164 were amplified by using restriction fragment length polymorphism (RFLP) and allelic specific polymerase chain reaction methods. All asthmatics had their serum IgE (total and specific) antibody or skin-prick test measured, bronchial reactivity to methacholine (Mch) and bronchial reversibility by β2-agonist evaluated.Results (1) The frequency of Gly 16 homozygous was significantly higher in the asthmatic group than that in healthy controls (22.4% vs. 8.3%, P＜ 0.05), OR was 2.9 with 95% CI 1.26-6.78. The proportion of Gly 16 allele was also higher in asthmatics than that in control (0.46 vs. 0.36, P ＜ 0.05); Gly16 homozygous was not independently associated with asthma pathogenesis (P= 0.21, OR 0.42 with 95% CI 0.11-1.61). (2) Of 51 night attack patients, 18 carrying Gly16 homozygosity, if compared with 10 of 74 nonnocturnal asthmatics carrying this genotype, there was significant difference between these two groups (35.3% vs. 13.5%, P ＜ 0.01). (3) The average dose of PD20-Mch was significantly lower in patients carrying Gln 27homozygous than those carrying homozygous Glu 27 and Gln/Glu 27 heterozygous (0.2 0.3, 1.6 0.8, and 2.1 3.0 μ, mol/L,P ＜ 0.05).Conclusion β2-AR gene polymorphisms might confer susceptibility to asthma in Chinese Northern patients. β2-AR gene,coordinated with other candidate loci, plays a role in the development of asthma.