AIM: To investigate the correlation between ezrin expression and invasive phenotype formation in malignantly transformed esophageal epithelial cells.
METHODS: The experimental cell line employed in the present study w...AIM: To investigate the correlation between ezrin expression and invasive phenotype formation in malignantly transformed esophageal epithelial cells.
METHODS: The experimental cell line employed in the present study was originated form the progressive induction of a human embryonic esophageal epithelial cell line (SHEE)by the E6E7 genes of human papillomavirus (HPV) type 18.The cells at the 35th passage after induction called SHEEIMM were in a state of immortalized phase and used as the control,while that of the 85th passage denominated as SHEEMT represented the status of cells that were malignantly transformed. The expression changes of ezrin and its mRNA in both cell passages were respectively analyzed by RT-PCR and Western blot. Invasive phenotype was assessed in vivo by inoculating these cells into the severe combined immunodeficient (SCID) mice via subcutaneous and intraperitoneal injection, and in vitro by inoculating them on the surface of the amnion membranes, which then was determined by light microscopy and scanning electron microscopy.
RESULTS: Upregulated expression of ezrin protein and its mRNA was observed in SHEEMT compared with that in SHEEIMM cells. The SHEEMT cells inoculated in SCID mice were observed forming tumor masses in both visceral organs and soft tissues in a period of 40 days with a special propensity to invading mesentery and pancreas, but did not exhibit hepatic metastases. Pathologically, these tumor cells harboring larger nucleus, nucleolus and less cytoplasm could infiltrate and destroy adjacent tissues. In the in vitro study,the inoculated SHEEMT cells could grow in cluster on the amniotic epithelial surface and intrude into the amniotic stroma. In contrast, unrestricted growth and invasiveness were not found in SHEEIMM cells in both in vivo and in vitroexperiment.
CONCLUSION: The upregulated ezrin expression is one of the important factors that are possibly associated with the invasive phenotype formation in malignantly transformed esophageal epithelial cells.展开更多
AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured h...AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured human lymphoma Jurkat T cell line or hepatoma cell line, Bel7402 in vitro. The expression of tumor necrosis factor related apoptosisinducing ligand (TRAIL) and its receptor (TRAILR) mRNA were analyzed by Northern blot and Western blot wasused to detect the expression of Fas and Fas ligand (FasL)protein.RESULTS: AFP (20 mg/L) could promote the expression of FasL and TRAIL, and inhibit the expression of Fas and TRAILR of Bel7402 cells. For Jurkat cell line, AFP could suppress the expression of FasL and TRAIL, and stimulate the expression of Fas and TRAILR. AFP also could synergize with Bel7402 cells to inhibit the expression of FasL protein and TRAIL mRNA in Jurkat cells. The monoclonal antibody against AFP (anti-AFP) could abolish these functions of AFP.CONCLUSION: AFP is able to promote the expression of FasL and TRAIL in hepatoma cells and enhance the expression of Fas and TRAILR in lymphocytes. These could elicit the escape of hepatocellular carcinoma cells from the host's lymphocytes immune surveillance.展开更多
AIM: Recent clinical epidemiological studies havedemonstrated the preventive effect of non-steroidal anti-inflammatory drugs (NSAIDs) against colorectal cancer.The underlying mechanism might be the inhibition of rate-...AIM: Recent clinical epidemiological studies havedemonstrated the preventive effect of non-steroidal anti-inflammatory drugs (NSAIDs) against colorectal cancer.The underlying mechanism might be the inhibition of rate-limiting enzyme cyclooxygenase-2 (COX-2) in metabolismof arachidonic acid. The role of COX-2 in carcinogenesisof colorectal cancer and its relationship with tumorbiological characteristics and patients′ prognosis stillremain unclear. This study was to investigate the role ofCOX-2 expression in carcinogenesis of colorectal cancerand its relationship with tumor biological characteristicsand patients′ prognosis.METHODS: A total of 139 colorectal cancers and 19adenomas surgically treated in School of Oncology, PekingUniversity, from January 1993 to September 2001 wereretrospectively studied. COX-2 expression was detected withtissue microarray (TMA) and immunohistochemistry (IHC)procedure. The association between COX-2 expression andclinicopathological features and its influence on patients′prognosis were studied.RESULTS: COX-2 expression was strong in colorectal cancer,moderate in adenoma and weak in normal mucosa, whichdemonstrated statistically significant difference (x2=46.997,P＜0.001). COX-2 expression had no association withclinicopathological features such as gross type,differentiation, invasion depth, vessel emboli and TNMstaging. Cox proportional hazards modeling analysis and Logrank test revealed no prognostic role of COX-2 expressionin colorectal cancer patients.CONCLUSION: COX-2 may play an important role in theearly stage of carcinogenesis, and its expression in colorectalcancer is not associated with clinicopathological features and patients′ prognosis.展开更多
In macrophages, the accumulation of cholesteryl esters synthesized by the activated acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) results in the foam cell formation, a hallmark of early atherosclerotic lesions...In macrophages, the accumulation of cholesteryl esters synthesized by the activated acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) results in the foam cell formation, a hallmark of early atherosclerotic lesions. In this study, with the treatment of a glucocorticoid hormone dexamethasone (Dex), lipid staining results clearly showed the large accumulation of lipid droplets containing cholesteryl esters in THP-1-derived macrophages exposed to lower concentration of the oxidized low-density lipoprotein (ox-LDL). More notably, when treated together with specific anti-ACAT inhibitors, the abundant cholesteryl ester accumulation was markedly diminished in THP-1-derived macrophages, confirming that ACAT is the key enzyme responsible for intracellular cholesteryl ester synthesis. RT-PCR and Western blot results indicated that Dex caused up-regulation of human ACAT1 expression at both the mRNA and protein levels in THP-1 and THP-1-derived macrophages. The luciferase activity assay demonstrated that Dex could enhance the activity of human ACAT1 gene P1 promoter, a major factor leading to the ACAT1 activation, in a cell-specific manner. Further experimental evidences showed that a glucocorticoid response element (GRE) located within human ACAT1 gene P1 promoter to response to the elevation of human ACAT1 gene expression by Dex could be functionally bound with glucocorticoid receptor (GR) proteins. These data supported the hypothesis that the clinical treatment with Dex, which increased the incidence of atherosclerosis, may in part due to enhancing the ACAT1 expression to promote the accumulation of cholesteryl esters during the macrophage-derived foam cell formation, an early stage of atherosclerosis.展开更多
AIM: To investigate the levels of D-dimer(DD) and von Willebrand factor(vWF) and the relationship between DD and vWF in ulcerative colitis(UC) patients. METHODS: A total of 29 plasma specimens were obtained from patie...AIM: To investigate the levels of D-dimer(DD) and von Willebrand factor(vWF) and the relationship between DD and vWF in ulcerative colitis(UC) patients. METHODS: A total of 29 plasma specimens were obtained from patients with ulcerative colitis (male 13, female 16) aged 21-47 years (33+/-11). Disease activity was assessed by Truelove-Writeria. Patients with a score of above 5 were regarded as having active colitis. Twenty healthy people(male 12, female 8) aged 19-53 years(31+/-14) served as normal controls. Blood samples were taken from an antecubital vein puncture. Blood(1.8 mL) was injected into the tubes containing sodium citrate (0.13 mmol/L). The plasma was obtained by centrifugation at 3000 r.min(-1) for 10 min, and stored at -80 degrees until assayed by ELISA. RESULTS: The mean plasma levels of DD and vWF in active UC patients were significantly higher than those of the controls (0.69+/-0.41 vs 0.27+/-0.11, P【0.01 143+/-46 vs 103+/-35, P【0.01). The mean plasma levels of DD in the patients with active disease were higher than those with inactive disease(0.69+/-0.41 vs 0.48+/-0.29 P【0.05). The levels of vWF were not different between active and inactive patients. DD levels were positively related to vWF levels( r =0.574, P【0.01). There was no significant difference between levels of DD and vWF and the scope of disease and sex of the patients. CONCLUSION: vWF is an important feature and a good marker of UC intravascular thrombus and endothelial cell dysfunction were found in UC patients and the combined test of DD and vWF is helpful to distinguish the activity of the UC patients.展开更多
In 1990, nanobacterium was found and named by Kajander.~1 With distinct mineralizing ability, nanobacteria are thought to play a role in extraskeletal calcifying diseases. It have been found in many human tissues, but...In 1990, nanobacterium was found and named by Kajander.~1 With distinct mineralizing ability, nanobacteria are thought to play a role in extraskeletal calcifying diseases. It have been found in many human tissues, but whether they exist in the bile or gallbladder mucosa remains unclear. The present study was undertaken to investigate by ELISA, bacterial culturing, immunohistochemical staining and transmission electron microscopy (TEM), whether nanobacteria exist in serum, bile or gallbladder mucosa of healthy people and patients with cholecystolithiasis.展开更多
AIM:To investigate the molecular mechanism of alphafetoprotein (AFP) on regulating the proliferation of human hepatocellular carcinoma cells.METHODS: Alpha-fetoprotein purified from human umbilical blood was added to ...AIM:To investigate the molecular mechanism of alphafetoprotein (AFP) on regulating the proliferation of human hepatocellular carcinoma cells.METHODS: Alpha-fetoprotein purified from human umbilical blood was added to cultured human hepatocellular carcinoma Bel 7402 cells in vitro for various treatment periods. The expression of c-fos, c-jun,and N-ras mRNA involved in proliferation and differentiation of cells was analyzed by Northern blot,and the expression of mutative p53 and p21^ras proteins was determined by Western blot.RESULTS:The results showed that AFP (20mg/L) stimulated mRNA expression of these oncogenes in Bel 7402 cells.The expression of c-fos mRNA increased by 51.1%,60.9%,96.0%,and 25.5% at 2, 6, 12, and 24 h, respectively.The expression of c-jun and N-ras mRNA reached to the maximum which increased by 81.3% and 59.9% as compared with the control alter 6h and 24h incubation with AFP, respectively.Western blot assay also demonstrated that AFP promoted the expression of mutative p53 and p21^ras proteins, and the increased rate of those proteins was 13.0%,39.9%, and 70.9%, as well as 35.2%, 102.6%, and 46.8% at 6, 12, and 24h,respectively, as compared with the control.Both human serum albumin (the same dosage as AFP) and monoclonal anti-AFP antibody failed to stimulate the expression of these oncogenes,but anti-AFP antibody could block the functions of AFP.CONCLUSION:The data indicate that AFP can stimulate the expression of some oncogenes to enhance the proliferation of human hepatocellular carcinoma Bel 7402 cells.展开更多
AIM: To study the effects of Radix Puerariae flavones (RPF) on liver lipid metabolism in ovariectomized (OVX) rats.METHODS: Forty adult female Wistar rats were randomly divided into four groups: OVX group; sham-OVX gr...AIM: To study the effects of Radix Puerariae flavones (RPF) on liver lipid metabolism in ovariectomized (OVX) rats.METHODS: Forty adult female Wistar rats were randomly divided into four groups: OVX group; sham-OVX group;OVX+estrogen group and OVX+RPF group. One week after operation rats of the first two groups were treated with physiological saline, rats of OVX+estrogen group with estrogen (1 mg/kg.b.w.) and rats of OVX+RPF group with RPF (100 mg/kg.b.w.), respectively for 5 weeks. After the rats were killed, their body weight, the weight of the abdominal fat and uterus were measured, and the levels of total cholesterol (TC) and triglyceride (TG) in liver homogenate were determined.RESULTS: Compared with the sham-OVX group, the body mass of the rats in OVX group was found ino-eased significantly;more abdominal fat in store; TC and TG in liver increased and uterine became further atrophy. As a result, the RPF was found to have an inhibitive action on those changes of various degrees.CONCLUSION: RPF has estrogen-like effect on lipid metabolism in liver and adipose tissue.展开更多
AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelia...AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and to quantify their synergistic activity.METHODS: Microcarriers (MCs) coated with human microvascular endothelial cells (HMVECs) were embedded in fibrin gel and cultured in 24-well plates with assay media. The growth factors bFGF, or VEGF, or both were added to the system. The wells (n = 8/group) were digitally photographed and the average length of capillary-like sprouts (ALS) from each microcarrier was quantitated.RESULTS: In aprotinin-stabilized fibrin matrix, human microvascular endothelial cells on the MCs invaded fibrin,forming sprouts and capillary networks with lumina. The angiogenic effects of bFGF or VEGF were dose-clependent in bhe range from 10 to 40 ng/mL. At d 1, 10 ng/mL of bFGF and VEGF induced angiogenesis with an ALS of 32.13±16.6 μm and 43.75±27.92 μm, respectively, which were significantly higher than that of the control (5.88±4.45 μm, P<0.01),and the differences became more significant as the time increased. In addition, the combination of 10 ng/mL of bFGF and VEGF each induced a more significant effect than the summed effects of bFGF (10 ng/mL) alone and VEGF (10 ng/mL) alone when analyzed using SPSS system for general linear model (GLM) (P= 0.011), and bhat also exceeded the effects by 20 ng/mL of either bFGF or VEGF.CONCLUSION: A microcarrier-based in vitro threedimensional angiogenesis model can be developed in fibrin.It offers a unique system for quantitative analysis of angiogenesis. Both bFGF and VEGF exert their angiogenic effects on HMVECs synergistically and in a dose-dependent manner.展开更多
A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of abo...A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of about 160 d.It also shows a pleiotropic phenotype, e.g., slow germination and lower germination rate, lower growth rate, curlingleaves and abnormal floral organs. The drm1 mutation was a single recessive nuclear mutation, which was mapped tothe bottom of chromosome 5 and located within a region of 20-30 kb around MXK3.1. There have been no mutantswith similar phenotypes reported in the literature, suggesting that DRM1 is a novel flowering promoting locus. Thefindings that the drm1 flowered lately under all photoperiod conditions and its late flowering phenotype was significantlyrestored by vernalization treatment suggest that the drm1 is a typical late flowering mutant and most likely associatedwith the autonomous flowering pathway. The conclusion was further confirmed by the revelation that the transcriptlevel of FLC was constantly upregulated in the drm1 at all the developmental phases examined, except for a very earlystage. Moreover, the transcript levels of two other important repressors, EMF and TFL1, were also upregulated in thedrm1, implying that the two repressors, along with FLC, seems to act in parallel pathways in the drm1 to regulateflowering as well as other aspects of floral development in a negatively additive way. This helps to explain why the drm1exhibits a much more severe late-flowering phenotype than most late-flowering mutants reported. It also implies that theDRM1 might act upstream of these repressors.展开更多
AIM: Available experimental evidence from both clinical andanimal models shows that both Chinese medicines tetrandine(Tet) and Qing Yi Tong (QYT) have positive treatment effectson acute pancreatitis (AP). This investi...AIM: Available experimental evidence from both clinical andanimal models shows that both Chinese medicines tetrandine(Tet) and Qing Yi Tong (QYT) have positive treatment effectson acute pancreatitis (AP). This investigation was conductedto explore the treatment mechanisms of Tet and QYT on APat the molecular level and thereby explain their therapeuticaffects. It included an invest igation of the effects of thesedrugs on gene expression of both intercellular adhesionmolecule 1 (ICAM-1) and superoxide dismutase (Mn-SODand Cu, Zn-SOD) in a rat model with ARMETHODS: AP in the test rats was induced by subjectingthem to laparotomy followed by a retrograde injection of 4 %sodium taurocholate into the bilio-pancreatic duct. The testrats with AP were divided into three groups. One was treatedwith Tet, one with QYT, and one with normal saline solution.The sham-operated control group (SO) rats were only subjectedto laparotomy. They were given no further treatment. For theTet group, Tet was injected intraperitoneally, and for the QYTgroup, QYT was given with a nose-gastric catheter. Theseprocedures were done at both 10 min and 5 h after APinduction. The levels of ICAM-1 mRNA expression and ofSOD (Mn-SOD and Cu, Zn-SOD) mRNA expression in thepancreas and liver tissues were measured by RT-PCR at 1,5, and 10 h after AP induction.RESULTS: When compared with the SO group during theobservation time, rats with AP showed a higher expressionof ICAM and a lower expression of Mn-SOD in both pancreasand liver tissues, and a lower expression of Cu, Zn-SOD inthe pancreas. Tet treatment attenuated changes in theexpression of both ICAM-1, and SOD (Mn-SOD and Cu, Zn-SOD) to a significant degree. A similar effect on theexpression of SOD (Mn-SOD and Cu, Zn-SOD) was also foundin the QYT group, but no obvious suppressive effect onICAM-1 expression was observed.CONCLUSION: The results of this study suggest that oneof the main mechanisms of Tet and QYT in treating AP is toenhance anti-oxidation of the body. The results also suggestthat the anti-in展开更多
NF-κB is a transcription factor of eukaryote,whose family comprises five members in mammals and three in drosophila.Transcription factors of the NF-κB family are activated in response to signals that lead to cell gr...NF-κB is a transcription factor of eukaryote,whose family comprises five members in mammals and three in drosophila.Transcription factors of the NF-κB family are activated in response to signals that lead to cell growth,differentiation,apoptosis and other events.NF-κB takes part in expression of numerous cytokines and adhesion molecules which are critical elements involved in the regulation of immune responses.In this review, we focus on our current understanding of NF-κB signal pathway and its role in the innate and adaptive immune responses in which these transcription factors have a key regulatory function.Furthermore we review what is currently known about their effects associated with apoptosis.Cellular & Molecular Immunology.2004; 1(5):343-350.展开更多
AIM: To find a cost-effective method of preparation of short interfering RNAs based on cloning, fermentation, digestion and purification (CFDP) and test its feasibility to inhibit hepatitis B virus replication in cell...AIM: To find a cost-effective method of preparation of short interfering RNAs based on cloning, fermentation, digestion and purification (CFDP) and test its feasibility to inhibit hepatitis B virus replication in cell culture. METHODS: We constructed an expression vector containing T7 and tac promoter in a head-to-head orientation. cDNA fragment of interest was cloned into this vector between the opposing promoters. dsRNAs were expressed with this vector in Escherichia coli, and purified by affinity chromatography using CF 11 column. They were digested by RNase III in a buffer containing manganese ions, then separated on 15% non-denaturing PAGE, and the siRNAs about 25 bp in length were recovered. siRNAs prepared with CFDP were co-transfected with target gene expression plasmid into human cell lines with lipofectamine 2 000 to test their inhibition efficiency. RESULTS: siRNAs corresponding to part of the hepatitis B virus polymerase gene (siHBVP) prepared by CFDP specifically and dramatically suppressed the virus protein expression. The HBsAg expression level was reduced to 10% that of the control by co-transfection of 60 nmol/L siHBVP in SMMC7721 cells. Dose-dependent effect on suppression of HBsAg and HBeAg expression was observed in HepG2 cells. The highest inhibition rate was kept at 70% during the six days after transfection of 7.5 nmol/L siHBVP. CONCLUSION: We show CFDP is a very promising method to prepare therapeutic agents in anti-virus applications.展开更多
AIM: Cyclooxygenase-2 (COX-2) is one of the rate-limiting enzymes in metabolism of arachidonic acid, and COX-2 inhibitors demonstrate preventive effects on cancer,especially on colorectal cancer. The underlying mechan...AIM: Cyclooxygenase-2 (COX-2) is one of the rate-limiting enzymes in metabolism of arachidonic acid, and COX-2 inhibitors demonstrate preventive effects on cancer,especially on colorectal cancer. The underlying mechanism remains unclear. The aim of this study was to illustrate the relationship between angiogenesis and COX-2 in carcinogenesis of colorectal cancer.METHODS: One hundred and seventy patients with colorectal cancer were enrolled in our study from January 1993 to September 2001 in School of Oncology, PekingUniversity. COX-2 and VEGF expression were detected with the immunohistochemistry (IHC) technique. IHC assays were carried out with the aid of tissue microarray (TMA)procedure. Specimens from 35 of these patients were examined with reverse transcriptase PCR (RT-PCR).RESULTS: COX-2 and VEGF expressions were stronger in colorectal cancer than those in the corresponding normal tissues, at both protein and mRNA levels. One hundred patients were eligible for analysis after IHC assay of COX-2 and VEGF. The positive rate of VEGF was much higher in COX-2 positive group (47/85) than in COX-2 negative group (x^2 = 4.181, P= 0.041). The result was further verified by the result of RT-PCR (x^2 = 8.517, P = 0.003). Correlation coefficient was 0.409 after Spearman correlation analysis (P=0.015).CONCLUSION: COX-2 may be involved in the course of tumor angiogenesis of colorectal cancer and acts through VEGF.展开更多
AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells. METHODS: Recombinant complex of HDL and aclacinomycin (rHDL-ACM) was...AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells. METHODS: Recombinant complex of HDL and aclacinomycin (rHDL-ACM) was prepared by cosonication of apoproteins from HDL (Apo HDL) and ACM as well as phosphatidylcholine. Characteristics of the rHDL-ACM were elucidated by electrophoretic mobility, including the size of particles, morphology and entrapment efficiency. Binding activity of rHDL-ACM to human hepatoma cells was determined by competition assay in the presence of excess native HDL. The cytotoxicity of rHDL-ACM was assessed by MTT method. RESULTS: The density range of rHDL-ACM was 1.063-1.210 g/mL, and the same as that of native HDL. The purity of all rHDL-ACM preparations was more than 92%. Encapsulated efficiencies of rHDL-ACM were more than 90%. rHDL-ACM particles were typical sphere model of lipoproteins and heterogeneous in particle size. The average diameter was 31.26±5.62 nm by measure of 110 rHDL-ACM particles in the range of diameter of lipoproteins. rHDL-ACM could bind on SMMC-7721 cells, and such binding could be competed against in the presence of excess native HDL. rHDL-ACM had same binding capacity as native HDL. The cellular uptake of rHDL-ACM by SMMC-7721 hepatoma cells was significantly higher than that of free ACM at the concentration range of 0.5-10 μg/mL (P<0.01). Cytotoxicity of rHDL-ACM to SMMC-7721 cells was significantly higher than that of free ACM at concentration range of less than 5 ug/mL (P<0.01) and IC50 of rHDL-ACM was lower than IC50 of free ACM (1.68 nmol/L vs3 nmol/L). Compared to L02 hepatocytes, a normal liver cell line, the cellular uptake of rHDL-ACM by SMMC-7721 cells was significantly higher (P<0.01) and in a dose-dependent manner at the concentration range of 0.5-10 μg/mL.Cytotoxicity of the rHDL-ACM to SMMC- 7721 cells was significantly higher than that to L02 cells at concentration range of 1-7.5μg/mL (P<0.01). IC50 for SMMC-7721 cells (1.68 nmol/L) was lower than 展开更多
AIM: To study the oxidative DNA damage to adolescents of hepatocellular carcinoma (HCC) families in Guangxi Zhuang Autonomous Region, China.METHODS: Peripheral leukocytes' DNA 7, 8-dihydro-8-oxoguanine (8-oxoG) an...AIM: To study the oxidative DNA damage to adolescents of hepatocellular carcinoma (HCC) families in Guangxi Zhuang Autonomous Region, China.METHODS: Peripheral leukocytes' DNA 7, 8-dihydro-8-oxoguanine (8-oxoG) and repair enzyme hOGG1 were quantified by flow-cytometry. hOGG1-Cys326Ser single nucleotide polymorphism (SNP) was distinguished by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) assay.RESULTS: There was a positive correlation between 8-oxoG and repair enzyme hOGG1 expression (P＜0.001). HCC children (n=21) in Fusui county had a higher level of hOGG1(P＜0.01) and a lower level of 8-oxoG (P＜0.05) than the controls (n=63) in Nanning city. Children in Nanning exposed to passive-smoking had a higher hOGG1 expression (P＜0.05)than the non-exposers. 8-oxoG and hOGG1 were negatively correlated with body mass index, while hOGG1 was positively correlated with age. There was a peak of 8-oxoG level nearby the 12 year point. Individuals with the hOGG1 326Ser allele had a significantly marginal higher concentration of leukocyte 8-oxoG level than hOGG1 326Cys allele.CONCLUSION: This is the first report using flow-cytometry to simultaneously quantify both the DNA oxidative damage and its repairing enzyme hOGG1. The results provide new insights towards a better understanding of the mechanisms of oxidative stress in a population highly susceptible to hepatocarcinogenesis.展开更多
Water channel proteins facilitate water flux across cell membranes and play important roles in plant growth and development. By GUS histochemical assay in RWC3 promoter-GUS transgenic rice (Oryza sativa L. cv. Shenxia...Water channel proteins facilitate water flux across cell membranes and play important roles in plant growth and development. By GUS histochemical assay in RWC3 promoter-GUS transgenic rice (Oryza sativa L. cv. Shenxiangjin 4), one of the members of water channel proteins in rice, RWC3, was found to distribute widely in variety of organs, from vegetative and reproductive organs. Further studies showed that gibberellin (GA) enhanced the GUS activity in the transgenic calli, suspension cells and leaves, whereas ancymidol (anc), an inhibitor of GA synthesis, reduced the GUS activity. Sucrose was found to inhibit the effects induced by addition of GA, suggesting a possible cross-talk between GA and sucrose signaling on regulation of the RWC3 gene expression.展开更多
AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polype...AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.展开更多
基金the National Natural Science Foundation of China (No.39830380,39900069)Research and Development Foundation of Shantou University(L00012)the Chinese National Human Genome Center,Beijing
文摘AIM: To investigate the correlation between ezrin expression and invasive phenotype formation in malignantly transformed esophageal epithelial cells.
METHODS: The experimental cell line employed in the present study was originated form the progressive induction of a human embryonic esophageal epithelial cell line (SHEE)by the E6E7 genes of human papillomavirus (HPV) type 18.The cells at the 35th passage after induction called SHEEIMM were in a state of immortalized phase and used as the control,while that of the 85th passage denominated as SHEEMT represented the status of cells that were malignantly transformed. The expression changes of ezrin and its mRNA in both cell passages were respectively analyzed by RT-PCR and Western blot. Invasive phenotype was assessed in vivo by inoculating these cells into the severe combined immunodeficient (SCID) mice via subcutaneous and intraperitoneal injection, and in vitro by inoculating them on the surface of the amnion membranes, which then was determined by light microscopy and scanning electron microscopy.
RESULTS: Upregulated expression of ezrin protein and its mRNA was observed in SHEEMT compared with that in SHEEIMM cells. The SHEEMT cells inoculated in SCID mice were observed forming tumor masses in both visceral organs and soft tissues in a period of 40 days with a special propensity to invading mesentery and pancreas, but did not exhibit hepatic metastases. Pathologically, these tumor cells harboring larger nucleus, nucleolus and less cytoplasm could infiltrate and destroy adjacent tissues. In the in vitro study,the inoculated SHEEMT cells could grow in cluster on the amniotic epithelial surface and intrude into the amniotic stroma. In contrast, unrestricted growth and invasiveness were not found in SHEEIMM cells in both in vivo and in vitroexperiment.
CONCLUSION: The upregulated ezrin expression is one of the important factors that are possibly associated with the invasive phenotype formation in malignantly transformed esophageal epithelial cells.
基金Supported by the National Natural Science Foundation of China,No. 30260117 and 30271174 the Natural Science Foundation of Hainan Province, No. 30315 the Educational Key Foundation of Hainan Province, No. 200322 the Nursery Foundation of Hainan Medical College, No. 200202
文摘AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured human lymphoma Jurkat T cell line or hepatoma cell line, Bel7402 in vitro. The expression of tumor necrosis factor related apoptosisinducing ligand (TRAIL) and its receptor (TRAILR) mRNA were analyzed by Northern blot and Western blot wasused to detect the expression of Fas and Fas ligand (FasL)protein.RESULTS: AFP (20 mg/L) could promote the expression of FasL and TRAIL, and inhibit the expression of Fas and TRAILR of Bel7402 cells. For Jurkat cell line, AFP could suppress the expression of FasL and TRAIL, and stimulate the expression of Fas and TRAILR. AFP also could synergize with Bel7402 cells to inhibit the expression of FasL protein and TRAIL mRNA in Jurkat cells. The monoclonal antibody against AFP (anti-AFP) could abolish these functions of AFP.CONCLUSION: AFP is able to promote the expression of FasL and TRAIL in hepatoma cells and enhance the expression of Fas and TRAILR in lymphocytes. These could elicit the escape of hepatocellular carcinoma cells from the host's lymphocytes immune surveillance.
文摘AIM: Recent clinical epidemiological studies havedemonstrated the preventive effect of non-steroidal anti-inflammatory drugs (NSAIDs) against colorectal cancer.The underlying mechanism might be the inhibition of rate-limiting enzyme cyclooxygenase-2 (COX-2) in metabolismof arachidonic acid. The role of COX-2 in carcinogenesisof colorectal cancer and its relationship with tumorbiological characteristics and patients′ prognosis stillremain unclear. This study was to investigate the role ofCOX-2 expression in carcinogenesis of colorectal cancerand its relationship with tumor biological characteristicsand patients′ prognosis.METHODS: A total of 139 colorectal cancers and 19adenomas surgically treated in School of Oncology, PekingUniversity, from January 1993 to September 2001 wereretrospectively studied. COX-2 expression was detected withtissue microarray (TMA) and immunohistochemistry (IHC)procedure. The association between COX-2 expression andclinicopathological features and its influence on patients′prognosis were studied.RESULTS: COX-2 expression was strong in colorectal cancer,moderate in adenoma and weak in normal mucosa, whichdemonstrated statistically significant difference (x2=46.997,P＜0.001). COX-2 expression had no association withclinicopathological features such as gross type,differentiation, invasion depth, vessel emboli and TNMstaging. Cox proportional hazards modeling analysis and Logrank test revealed no prognostic role of COX-2 expressionin colorectal cancer patients.CONCLUSION: COX-2 may play an important role in theearly stage of carcinogenesis, and its expression in colorectalcancer is not associated with clinicopathological features and patients′ prognosis.
基金supported by grants of the Major State Basic Research Development program of China(No.2002CB513000)National Scienses Foudation Center(No.30393110)+1 种基金State Science and Technology Committee(SSTC)(NO.02DJ14068)Chinese Academy of Science to Bo Liang LI,and NIH grant HL36709 to Ta Yuan CHANG.
文摘In macrophages, the accumulation of cholesteryl esters synthesized by the activated acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) results in the foam cell formation, a hallmark of early atherosclerotic lesions. In this study, with the treatment of a glucocorticoid hormone dexamethasone (Dex), lipid staining results clearly showed the large accumulation of lipid droplets containing cholesteryl esters in THP-1-derived macrophages exposed to lower concentration of the oxidized low-density lipoprotein (ox-LDL). More notably, when treated together with specific anti-ACAT inhibitors, the abundant cholesteryl ester accumulation was markedly diminished in THP-1-derived macrophages, confirming that ACAT is the key enzyme responsible for intracellular cholesteryl ester synthesis. RT-PCR and Western blot results indicated that Dex caused up-regulation of human ACAT1 expression at both the mRNA and protein levels in THP-1 and THP-1-derived macrophages. The luciferase activity assay demonstrated that Dex could enhance the activity of human ACAT1 gene P1 promoter, a major factor leading to the ACAT1 activation, in a cell-specific manner. Further experimental evidences showed that a glucocorticoid response element (GRE) located within human ACAT1 gene P1 promoter to response to the elevation of human ACAT1 gene expression by Dex could be functionally bound with glucocorticoid receptor (GR) proteins. These data supported the hypothesis that the clinical treatment with Dex, which increased the incidence of atherosclerosis, may in part due to enhancing the ACAT1 expression to promote the accumulation of cholesteryl esters during the macrophage-derived foam cell formation, an early stage of atherosclerosis.
文摘AIM: To investigate the levels of D-dimer(DD) and von Willebrand factor(vWF) and the relationship between DD and vWF in ulcerative colitis(UC) patients. METHODS: A total of 29 plasma specimens were obtained from patients with ulcerative colitis (male 13, female 16) aged 21-47 years (33+/-11). Disease activity was assessed by Truelove-Writeria. Patients with a score of above 5 were regarded as having active colitis. Twenty healthy people(male 12, female 8) aged 19-53 years(31+/-14) served as normal controls. Blood samples were taken from an antecubital vein puncture. Blood(1.8 mL) was injected into the tubes containing sodium citrate (0.13 mmol/L). The plasma was obtained by centrifugation at 3000 r.min(-1) for 10 min, and stored at -80 degrees until assayed by ELISA. RESULTS: The mean plasma levels of DD and vWF in active UC patients were significantly higher than those of the controls (0.69+/-0.41 vs 0.27+/-0.11, P【0.01 143+/-46 vs 103+/-35, P【0.01). The mean plasma levels of DD in the patients with active disease were higher than those with inactive disease(0.69+/-0.41 vs 0.48+/-0.29 P【0.05). The levels of vWF were not different between active and inactive patients. DD levels were positively related to vWF levels( r =0.574, P【0.01). There was no significant difference between levels of DD and vWF and the scope of disease and sex of the patients. CONCLUSION: vWF is an important feature and a good marker of UC intravascular thrombus and endothelial cell dysfunction were found in UC patients and the combined test of DD and vWF is helpful to distinguish the activity of the UC patients.
文摘In 1990, nanobacterium was found and named by Kajander.~1 With distinct mineralizing ability, nanobacteria are thought to play a role in extraskeletal calcifying diseases. It have been found in many human tissues, but whether they exist in the bile or gallbladder mucosa remains unclear. The present study was undertaken to investigate by ELISA, bacterial culturing, immunohistochemical staining and transmission electron microscopy (TEM), whether nanobacteria exist in serum, bile or gallbladder mucosa of healthy people and patients with cholecystolithiasis.
基金Supported by the National Natural Science Foundation of China,No.30260117Natural Science Foundation of Hainan Province,No.30315 the Nursery Foundation of Hainan Medical College,No.200202
文摘AIM:To investigate the molecular mechanism of alphafetoprotein (AFP) on regulating the proliferation of human hepatocellular carcinoma cells.METHODS: Alpha-fetoprotein purified from human umbilical blood was added to cultured human hepatocellular carcinoma Bel 7402 cells in vitro for various treatment periods. The expression of c-fos, c-jun,and N-ras mRNA involved in proliferation and differentiation of cells was analyzed by Northern blot,and the expression of mutative p53 and p21^ras proteins was determined by Western blot.RESULTS:The results showed that AFP (20mg/L) stimulated mRNA expression of these oncogenes in Bel 7402 cells.The expression of c-fos mRNA increased by 51.1%,60.9%,96.0%,and 25.5% at 2, 6, 12, and 24 h, respectively.The expression of c-jun and N-ras mRNA reached to the maximum which increased by 81.3% and 59.9% as compared with the control alter 6h and 24h incubation with AFP, respectively.Western blot assay also demonstrated that AFP promoted the expression of mutative p53 and p21^ras proteins, and the increased rate of those proteins was 13.0%,39.9%, and 70.9%, as well as 35.2%, 102.6%, and 46.8% at 6, 12, and 24h,respectively, as compared with the control.Both human serum albumin (the same dosage as AFP) and monoclonal anti-AFP antibody failed to stimulate the expression of these oncogenes,but anti-AFP antibody could block the functions of AFP.CONCLUSION:The data indicate that AFP can stimulate the expression of some oncogenes to enhance the proliferation of human hepatocellular carcinoma Bel 7402 cells.
基金Supported by the National Natural Science Foundation of China,No. 30330220 and the Natural Science Foundation of Beijing,No.7032024
文摘AIM: To study the effects of Radix Puerariae flavones (RPF) on liver lipid metabolism in ovariectomized (OVX) rats.METHODS: Forty adult female Wistar rats were randomly divided into four groups: OVX group; sham-OVX group;OVX+estrogen group and OVX+RPF group. One week after operation rats of the first two groups were treated with physiological saline, rats of OVX+estrogen group with estrogen (1 mg/kg.b.w.) and rats of OVX+RPF group with RPF (100 mg/kg.b.w.), respectively for 5 weeks. After the rats were killed, their body weight, the weight of the abdominal fat and uterus were measured, and the levels of total cholesterol (TC) and triglyceride (TG) in liver homogenate were determined.RESULTS: Compared with the sham-OVX group, the body mass of the rats in OVX group was found ino-eased significantly;more abdominal fat in store; TC and TG in liver increased and uterine became further atrophy. As a result, the RPF was found to have an inhibitive action on those changes of various degrees.CONCLUSION: RPF has estrogen-like effect on lipid metabolism in liver and adipose tissue.
文摘AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and to quantify their synergistic activity.METHODS: Microcarriers (MCs) coated with human microvascular endothelial cells (HMVECs) were embedded in fibrin gel and cultured in 24-well plates with assay media. The growth factors bFGF, or VEGF, or both were added to the system. The wells (n = 8/group) were digitally photographed and the average length of capillary-like sprouts (ALS) from each microcarrier was quantitated.RESULTS: In aprotinin-stabilized fibrin matrix, human microvascular endothelial cells on the MCs invaded fibrin,forming sprouts and capillary networks with lumina. The angiogenic effects of bFGF or VEGF were dose-clependent in bhe range from 10 to 40 ng/mL. At d 1, 10 ng/mL of bFGF and VEGF induced angiogenesis with an ALS of 32.13±16.6 μm and 43.75±27.92 μm, respectively, which were significantly higher than that of the control (5.88±4.45 μm, P<0.01),and the differences became more significant as the time increased. In addition, the combination of 10 ng/mL of bFGF and VEGF each induced a more significant effect than the summed effects of bFGF (10 ng/mL) alone and VEGF (10 ng/mL) alone when analyzed using SPSS system for general linear model (GLM) (P= 0.011), and bhat also exceeded the effects by 20 ng/mL of either bFGF or VEGF.CONCLUSION: A microcarrier-based in vitro threedimensional angiogenesis model can be developed in fibrin.It offers a unique system for quantitative analysis of angiogenesis. Both bFGF and VEGF exert their angiogenic effects on HMVECs synergistically and in a dose-dependent manner.
文摘A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of about 160 d.It also shows a pleiotropic phenotype, e.g., slow germination and lower germination rate, lower growth rate, curlingleaves and abnormal floral organs. The drm1 mutation was a single recessive nuclear mutation, which was mapped tothe bottom of chromosome 5 and located within a region of 20-30 kb around MXK3.1. There have been no mutantswith similar phenotypes reported in the literature, suggesting that DRM1 is a novel flowering promoting locus. Thefindings that the drm1 flowered lately under all photoperiod conditions and its late flowering phenotype was significantlyrestored by vernalization treatment suggest that the drm1 is a typical late flowering mutant and most likely associatedwith the autonomous flowering pathway. The conclusion was further confirmed by the revelation that the transcriptlevel of FLC was constantly upregulated in the drm1 at all the developmental phases examined, except for a very earlystage. Moreover, the transcript levels of two other important repressors, EMF and TFL1, were also upregulated in thedrm1, implying that the two repressors, along with FLC, seems to act in parallel pathways in the drm1 to regulateflowering as well as other aspects of floral development in a negatively additive way. This helps to explain why the drm1exhibits a much more severe late-flowering phenotype than most late-flowering mutants reported. It also implies that theDRM1 might act upstream of these repressors.
基金the National Natural Scientific Foundation of China, No.30060031
文摘AIM: Available experimental evidence from both clinical andanimal models shows that both Chinese medicines tetrandine(Tet) and Qing Yi Tong (QYT) have positive treatment effectson acute pancreatitis (AP). This investigation was conductedto explore the treatment mechanisms of Tet and QYT on APat the molecular level and thereby explain their therapeuticaffects. It included an invest igation of the effects of thesedrugs on gene expression of both intercellular adhesionmolecule 1 (ICAM-1) and superoxide dismutase (Mn-SODand Cu, Zn-SOD) in a rat model with ARMETHODS: AP in the test rats was induced by subjectingthem to laparotomy followed by a retrograde injection of 4 %sodium taurocholate into the bilio-pancreatic duct. The testrats with AP were divided into three groups. One was treatedwith Tet, one with QYT, and one with normal saline solution.The sham-operated control group (SO) rats were only subjectedto laparotomy. They were given no further treatment. For theTet group, Tet was injected intraperitoneally, and for the QYTgroup, QYT was given with a nose-gastric catheter. Theseprocedures were done at both 10 min and 5 h after APinduction. The levels of ICAM-1 mRNA expression and ofSOD (Mn-SOD and Cu, Zn-SOD) mRNA expression in thepancreas and liver tissues were measured by RT-PCR at 1,5, and 10 h after AP induction.RESULTS: When compared with the SO group during theobservation time, rats with AP showed a higher expressionof ICAM and a lower expression of Mn-SOD in both pancreasand liver tissues, and a lower expression of Cu, Zn-SOD inthe pancreas. Tet treatment attenuated changes in theexpression of both ICAM-1, and SOD (Mn-SOD and Cu, Zn-SOD) to a significant degree. A similar effect on theexpression of SOD (Mn-SOD and Cu, Zn-SOD) was also foundin the QYT group, but no obvious suppressive effect onICAM-1 expression was observed.CONCLUSION: The results of this study suggest that oneof the main mechanisms of Tet and QYT in treating AP is toenhance anti-oxidation of the body. The results also suggestthat the anti-in
文摘NF-κB is a transcription factor of eukaryote,whose family comprises five members in mammals and three in drosophila.Transcription factors of the NF-κB family are activated in response to signals that lead to cell growth,differentiation,apoptosis and other events.NF-κB takes part in expression of numerous cytokines and adhesion molecules which are critical elements involved in the regulation of immune responses.In this review, we focus on our current understanding of NF-κB signal pathway and its role in the innate and adaptive immune responses in which these transcription factors have a key regulatory function.Furthermore we review what is currently known about their effects associated with apoptosis.Cellular & Molecular Immunology.2004; 1(5):343-350.
文摘AIM: To find a cost-effective method of preparation of short interfering RNAs based on cloning, fermentation, digestion and purification (CFDP) and test its feasibility to inhibit hepatitis B virus replication in cell culture. METHODS: We constructed an expression vector containing T7 and tac promoter in a head-to-head orientation. cDNA fragment of interest was cloned into this vector between the opposing promoters. dsRNAs were expressed with this vector in Escherichia coli, and purified by affinity chromatography using CF 11 column. They were digested by RNase III in a buffer containing manganese ions, then separated on 15% non-denaturing PAGE, and the siRNAs about 25 bp in length were recovered. siRNAs prepared with CFDP were co-transfected with target gene expression plasmid into human cell lines with lipofectamine 2 000 to test their inhibition efficiency. RESULTS: siRNAs corresponding to part of the hepatitis B virus polymerase gene (siHBVP) prepared by CFDP specifically and dramatically suppressed the virus protein expression. The HBsAg expression level was reduced to 10% that of the control by co-transfection of 60 nmol/L siHBVP in SMMC7721 cells. Dose-dependent effect on suppression of HBsAg and HBeAg expression was observed in HepG2 cells. The highest inhibition rate was kept at 70% during the six days after transfection of 7.5 nmol/L siHBVP. CONCLUSION: We show CFDP is a very promising method to prepare therapeutic agents in anti-virus applications.
文摘AIM: Cyclooxygenase-2 (COX-2) is one of the rate-limiting enzymes in metabolism of arachidonic acid, and COX-2 inhibitors demonstrate preventive effects on cancer,especially on colorectal cancer. The underlying mechanism remains unclear. The aim of this study was to illustrate the relationship between angiogenesis and COX-2 in carcinogenesis of colorectal cancer.METHODS: One hundred and seventy patients with colorectal cancer were enrolled in our study from January 1993 to September 2001 in School of Oncology, PekingUniversity. COX-2 and VEGF expression were detected with the immunohistochemistry (IHC) technique. IHC assays were carried out with the aid of tissue microarray (TMA)procedure. Specimens from 35 of these patients were examined with reverse transcriptase PCR (RT-PCR).RESULTS: COX-2 and VEGF expressions were stronger in colorectal cancer than those in the corresponding normal tissues, at both protein and mRNA levels. One hundred patients were eligible for analysis after IHC assay of COX-2 and VEGF. The positive rate of VEGF was much higher in COX-2 positive group (47/85) than in COX-2 negative group (x^2 = 4.181, P= 0.041). The result was further verified by the result of RT-PCR (x^2 = 8.517, P = 0.003). Correlation coefficient was 0.409 after Spearman correlation analysis (P=0.015).CONCLUSION: COX-2 may be involved in the course of tumor angiogenesis of colorectal cancer and acts through VEGF.
基金Supported by the National Natural Science Foundation of China,No. 39770164
文摘AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells. METHODS: Recombinant complex of HDL and aclacinomycin (rHDL-ACM) was prepared by cosonication of apoproteins from HDL (Apo HDL) and ACM as well as phosphatidylcholine. Characteristics of the rHDL-ACM were elucidated by electrophoretic mobility, including the size of particles, morphology and entrapment efficiency. Binding activity of rHDL-ACM to human hepatoma cells was determined by competition assay in the presence of excess native HDL. The cytotoxicity of rHDL-ACM was assessed by MTT method. RESULTS: The density range of rHDL-ACM was 1.063-1.210 g/mL, and the same as that of native HDL. The purity of all rHDL-ACM preparations was more than 92%. Encapsulated efficiencies of rHDL-ACM were more than 90%. rHDL-ACM particles were typical sphere model of lipoproteins and heterogeneous in particle size. The average diameter was 31.26±5.62 nm by measure of 110 rHDL-ACM particles in the range of diameter of lipoproteins. rHDL-ACM could bind on SMMC-7721 cells, and such binding could be competed against in the presence of excess native HDL. rHDL-ACM had same binding capacity as native HDL. The cellular uptake of rHDL-ACM by SMMC-7721 hepatoma cells was significantly higher than that of free ACM at the concentration range of 0.5-10 μg/mL (P<0.01). Cytotoxicity of rHDL-ACM to SMMC-7721 cells was significantly higher than that of free ACM at concentration range of less than 5 ug/mL (P<0.01) and IC50 of rHDL-ACM was lower than IC50 of free ACM (1.68 nmol/L vs3 nmol/L). Compared to L02 hepatocytes, a normal liver cell line, the cellular uptake of rHDL-ACM by SMMC-7721 cells was significantly higher (P<0.01) and in a dose-dependent manner at the concentration range of 0.5-10 μg/mL.Cytotoxicity of the rHDL-ACM to SMMC- 7721 cells was significantly higher than that to L02 cells at concentration range of 1-7.5μg/mL (P<0.01). IC50 for SMMC-7721 cells (1.68 nmol/L) was lower than
基金the Guangxi Natural Sciences Grant,No.GKZ9912028 and No.GKJ0236030Guangxi Educational Committee Grant,No.GZBH 2000-272+1 种基金Guangxi Health Ministry Medicine Grant,No.Z2001087Singapore Science Grant,No.R-186-000-044-213
文摘AIM: To study the oxidative DNA damage to adolescents of hepatocellular carcinoma (HCC) families in Guangxi Zhuang Autonomous Region, China.METHODS: Peripheral leukocytes' DNA 7, 8-dihydro-8-oxoguanine (8-oxoG) and repair enzyme hOGG1 were quantified by flow-cytometry. hOGG1-Cys326Ser single nucleotide polymorphism (SNP) was distinguished by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) assay.RESULTS: There was a positive correlation between 8-oxoG and repair enzyme hOGG1 expression (P＜0.001). HCC children (n=21) in Fusui county had a higher level of hOGG1(P＜0.01) and a lower level of 8-oxoG (P＜0.05) than the controls (n=63) in Nanning city. Children in Nanning exposed to passive-smoking had a higher hOGG1 expression (P＜0.05)than the non-exposers. 8-oxoG and hOGG1 were negatively correlated with body mass index, while hOGG1 was positively correlated with age. There was a peak of 8-oxoG level nearby the 12 year point. Individuals with the hOGG1 326Ser allele had a significantly marginal higher concentration of leukocyte 8-oxoG level than hOGG1 326Cys allele.CONCLUSION: This is the first report using flow-cytometry to simultaneously quantify both the DNA oxidative damage and its repairing enzyme hOGG1. The results provide new insights towards a better understanding of the mechanisms of oxidative stress in a population highly susceptible to hepatocarcinogenesis.
文摘Water channel proteins facilitate water flux across cell membranes and play important roles in plant growth and development. By GUS histochemical assay in RWC3 promoter-GUS transgenic rice (Oryza sativa L. cv. Shenxiangjin 4), one of the members of water channel proteins in rice, RWC3, was found to distribute widely in variety of organs, from vegetative and reproductive organs. Further studies showed that gibberellin (GA) enhanced the GUS activity in the transgenic calli, suspension cells and leaves, whereas ancymidol (anc), an inhibitor of GA synthesis, reduced the GUS activity. Sucrose was found to inhibit the effects induced by addition of GA, suggesting a possible cross-talk between GA and sucrose signaling on regulation of the RWC3 gene expression.
基金National Science Foundation of China,No.30060091
文摘AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.
