Biomedical subjects

Li Wang

Publications and source records attributed to Li Wang.

At least 55 records · Page 3Linked to original sources

PubMed2006

TLR2 and TLR4 agonists synergistically up-regulate SR-A in RAW264.7 through p38.

It is known that macrophage scavenger receptor A (SR-A) can protect mice from endotoxemia. In addition, Escherichia coli O111:B4 LPS from Sigma (sLPS), which contains both TLR4 and TLR2 agonists, was previously reported to be able to induce SR-A expression on murine macrophage cell line RAW264.7. However, the relative role of both TLR4 and TLR2 agonists from Sigma (sLPS) in the up-regulation of SR-A on RAW264.7 is still undefined. Here, we found that sLPS could only slightly up-regulate SR-A on RAW264.7 following removing its TLR4 and TLR2 agonists, respectively. In contrast, the combination of TLR4 agonist uLPS (re-extracted sLPS) and TLR2 agonist Pam3CSK4 dramatically induced SR-A expression, and synergistically promoted RAW264.7 to bind and internalize FITC-LPS specifically through SR-A. The combination had no such effect either on TLR2 or TLR4 expression, and incubation with IL-6, IL-10, IL-12 or TNF-alpha alone could not induce SR-A expression on RAW264.7. In addition, treatment with a NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC) could only weakly suppress the up-regulation of SR-A by the combination. However, the combination synergistically promoted MAPK p38 phosphorylation, and p38 specific inhibitor SB203580 completely suppressed its inducible effect on SR-A expression. Hence, we demonstrated that up-regulation of SR-A by sLPS was resulted from the cooperation of its TLR4 and TLR2 agonists through p38, and we also presented a novel synergy effect of TLR2 and TLR4 agonists.

Animals↗

PubMed2006

Mammary carcinogenesis in transgenic mice expressing a dominant-negative mutant of DNA polymerase beta in their mammary glands.

DNA polymerase beta (polbeta) is a major contributor to mammalian DNA damage repair through its gap-filling DNA synthesis and 5'-deoxyribose phosphate lyase activities. In this way, polbeta plays pivotal roles in the repair of oxidative DNA damage, replication, embryonic survival, neuronal development, meiosis, apoptosis and telomere function. A 36 kDa truncated polbetaDelta protein is expressed in human colorectal, breast, lung and renal carcinomas, but not in normal matched tissues. Interestingly, a binary protein-protein complex of polbetaDelta and X-ray cross-complementing group 1 acts as dominant-negative mutant. In this study, the potential tumorigenic activity of polbetaDelta was examined in nude and transgenic mouse models. Mouse embryonic fibroblasts (MEFs) expressing polbetaDelta in the absence of endogenous polbeta exhibited increased susceptibility to N-methyl-N-nitrosourea (MNU)-induced morphological transformation as compared with cells expressing wild-type (WT) polbeta. This was accompanied by reduced gap-filling DNA synthesis activity. Anchorage-independent transformed cells derived from polbetaDelta-expressing MEFs induced 100% tumor occurrence in nude mice. To support these data, we established transgenic mice expressing polbetaDelta specifically in the mammary glands from a whey acidic protein promoter-driven transgene. This is the first report of transgenic mice with tissue-specific expression of polbetaDelta. MNU-induced tumor formation was analyzed in transgenic mice expressing polbetaDelta together with endogenous WT polbeta in their mammary glands and in normal control mice expressing only WT polbeta. The latent period of tumor appearance was markedly shorter and tumor incidence was significantly higher in transgenic animals than in control animals treated under the same conditions. These results indicate that cells expressing the mutant polbetaDelta display an enhanced sensitivity to MNU that probably underlies an increased susceptibility to tumorigenesis.

Animals↗

PubMed2006

Immortalization of bovine germ line stem cells by c-myc and hTERT.

The limited life span of bovine germ line stem cells in vitro is one of the obstacles to spermatogenesis analysis, genetic manipulation and generating transgenic animal. The aim of this study is to establish immortalized bovine germ line stem cells by c-myc or hTERT. We constructed pEMY and pETE expression vectors and transfected germ line cells from 5-month-old bovine. After G418 screening, four types of positive clones were obtained. The results showed that they expressed exogenous genes c-myc or hTERT at mRNA and protein level by RT-PCR and Western blotting detection. Presumable cell lines GM7, GT3, GMT5 all expressed germ-line-stem-cell-specific makers by immunocytochemical analysis, such as c-kit, Oct-4 and GFRalpha-1. The putative cell lines also had higher capacity of proliferation than freshly isolated bovine spermatogonial stem cells. So we can conclude that exogenous genes c-myc or hTERT have integrated into the genome of bovine germ cells and upregulated the expression of telomerase.

Animals↗

PubMed2006

Identification of differentially expressed genes in lipopolysaccharide-stimulated yellow grouper Epinephelus awoara spleen.

A subtracted cDNA library from lipopolysaccharide (LPS)-stimulated Epinephelus awoara spleen was constructed using the suppression subtractive hybridization (SSH). Random clones (209) were selected and sequenced. After assembling, 36 contigs and 56 singlets (accession numbers: EB410743-EB410834) were finally obtained, some of which were immune-related genes. A reverse transcription-polymerase chain reaction (RT-PCR) analysis of the expression patterns of eight transcripts showed that seven of them were up-regulated after 24 h of LPS stimulation. Furthermore, full-length cDNAs of homologues of defender against cell death 1 (DAD1) and allograft inflammatory factor-1 (AIF-1) were obtained by RACE-PCR.

Amino Acid Sequence↗

PubMed2006

Frequent epigenetic inactivation of spleen tyrosine kinase gene in human hepatocellular carcinoma.

PURPOSE: The aim of present study was to investigate the methylation and expression status of spleen tyrosine kinase (SYK) in human hepatocellular carcinoma (HCC) and to evaluate this information for its ability to predict disease prognosis. E-cadherin and TIMP-3 methylation was also analyzed here as control because both were associated with poor prognosis in some types of tumors. EXPERIMENTAL DESIGN: We analyzed the methylation status of SYK, E-cadherin, and TIMP-3 in 124 cases of HCC and assessed the correlation of such methylations with clinicopathologic variables and prognosis after tumor resection. RESULTS: We found that SYK, E-cadherin, and TIMP-3 genes were methylated in 27%, 27%, and 42% of HCC neoplastic tissues, respectively. The loss of SYK mRNA or Syk protein expression was highly correlated with SYK gene methylation. The patients with methylated SYK in neoplastic tissues had a significantly lower overall survival rate after hepatectomy than those with unmethylated SYK. No significant difference in overall survival rates, however, was found between groups of patients with methylated and unmethylated E-cadherin or TIMP-3. Patients with negative Syk protein expression had a significantly lower overall survival rate than those with positive Syk protein expression. Multivariate analyses indicated that factors affecting overall survival were tumor-node-metastasis stage, Child-Pugh classification, SYK methylation, or Syk protein status. CONCLUSIONS: Our results indicate that SYK methylation and loss of Syk expression in HCC neoplastic tissues are independent biomarkers of poor patient outcome and that determination of SYK methylation or Syk expression status may offer guidance for selecting appropriate treatments.

Adult↗

PubMed2006

Asymmetric dimethylarginine reduced erythrocyte deformability in streptozotocin-induced diabetic rats.

To investigate the effect of asymmetric dimethylarginine on erythrocyte deformability in streptozotocin-induced diabetic rats, a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg) in male Sprague-Dawley rats was carried out to induce diabetes and normal erythrocytes were incubated with asymmetric dimethylarginine or aortic rings from diabetic rats in the presence of L-arginine or vitamin E. We found that erythrocyte deformability was significantly decreased in diabetic rats. The levels of asymmetric dimethylarginine in plasma and erythrocytes of diabetic rats were elevated significantly from 2-week diabetic duration to 8-week diabetic duration. Nitric oxide in erythrocytes was decreased at 8-week diabetic duration while plasma nitric oxide remained unchanged all along. The content of malondialdehyde in erythrocytes of diabetic rats was increased. After incubation of erythrocytes with asymmetric dimethylarginine (10(-6) M) for 30 min, erythrocyte deformability and nitric oxide level in erythrocytes were decreased markedly. Reactive oxygen species and malondialdehyde production in erythrocytes were promoted by asymmetric dimethylarginine. Both L-arginine and vitamin E reversed the effects of asymmetric dimethylarginine. After incubation of erythrocytes with aortic rings from diabetic rats, erythrocyte deformability was decreased, which was attenuated by L-arginine. These results indicated that reduction of erythrocyte deformability in diabetic rats was associated with promoted oxidant stress as well as impaired nitric oxide synthesis by elevation of asymmetric dimethylarginine.

Animals↗

PubMed2006

CGI: a new approach for prioritizing genes by combining gene expression and protein-protein interaction data.

MOTIVATION: Identifying candidate genes associated with a given phenotype or trait is an important problem in biological and biomedical studies. Prioritizing genes based on the accumulated information from several data sources is of fundamental importance. Several integrative methods have been developed when a set of candidate genes for the phenotype is available. However, how to prioritize genes for phenotypes when no candidates are available is still a challenging problem. RESULTS: We develop a new method for prioritizing genes associated with a phenotype by Combining Gene expression and protein Interaction data (CGI). The method is applied to yeast gene expression data sets in combination with protein interaction data sets of varying reliability. We found that our method outperforms the intuitive prioritizing method of using either gene expression data or protein interaction data only and a recent gene ranking algorithm GeneRank. We then apply our method to prioritize genes for Alzheimer's disease. AVAILABILITY: The code in this paper is available upon request.

Algorithms↗

PubMed2006

Introduction of G1 phase arrest in Human Hepatocellular carcinoma cells (HHCC) by APMCF1 gene transfection through the down-regulation of TIMP3 and up-regulation of the CDK inhibitors p21.

We previously found that there was up-regulation of APMCF1 expression in apoptotic MCF-7 cells. Moreover, bioinformatics analysis has found that APMCF1 molecules had similar size and structure with molecules which belong to small G-protein superfamily. We presume that APMCF1 plays certain biological role in the regulation of cell proliferation and apoptosis. In this study, we first detected the expression pattern of APMCF1 in human hepatocellular carcinoma cell line and find no expression in Human Hepatocellular carcinoma cells (HHCC) and enhanced expression in HepG2 cells. Expression of liposome-mediated ectogenic APMCF1 induced inhibition of HHCC growth and cell cycle, and RNAi inhibited APMCF1 expression and promoted HepG2 cell growth. Results of cell cycle gene chips analysis showed up-regulation of p21 expression and down-regulation of TIMP3 in HHCC cells expressing ectogenic APMCF1, indicating that APMCF1 participates at least partially in cell cycle regulation through regulating genes such as p21 and TIMP3.

Carcinoma, Hepatocellular↗

PubMed2006

Lipoplex formulation of superior efficacy exhibits high surface activity and fusogenicity, and readily releases DNA.

Lipoplexes containing a mixture of cationic phospholipids dioleoylethylphosphatidylcholine (EDOPC) and dilauroylethylphosphatidylcholine (EDLPC) are known to be far more efficient agents in transfection of cultured primary endothelial cells than are lipoplexes containing either lipid alone. The large magnitude of the synergy permits comparison of the physical and physico-chemical properties of lipoplexes that have very different transfection efficiencies, but minor chemical differences. Here we report that the superior transfection efficiency of the EDLPC/EDOPC lipoplexes correlates with higher surface activity, higher affinity to interact and mix with negatively charged membrane-mimicking liposomes, and with considerably more efficient DNA release relative to the EDOPC lipoplexes. Observations on cultured cells agree with the results obtained with model systems; confocal microscopy of transfected human umbilical artery endothelial cells (HUAEC) demonstrated more extensive DNA release into the cytoplasm and nucleoplasm for the EDLPC/EDOPC lipoplexes than for EDOPC lipoplexes; electron microscopy of cells fixed and embedded directly on the culture dish revealed contact of EDLPC/EDOPC lipoplexes with various cellular membranes, including those of the endoplasmic reticulum, mitochondria and nucleus. The sequence of events outlining efficient lipofection is discussed based on the presented data.

Cell Membrane↗

PubMed2006

[Effects of gene therapy with replication-defective adenovirus ericlosing Egr-1 promoter and Smad7 cDNA on irradiation-induced pulmonary fibrosis: experiment with mice].

OBJECTIVE: To investigate the effects of gene therapy with replication-defective adenovirus enclosing Egr-1 promoter and Smad7 cDNA on irradiation-induced pulmonary fibrosis. METHODS: The recombinant replication-defective adenovirus AD. Egr-Smad7 enclosing Egr-1 promoter and Smad7 cDNA was constructed. 288 C57BL mice were randomly divided into 6 groups: AD. Egr-Smad7 group (Group RA, receiving intratracheal instillation of AD. Egr-Smad7 of the dose of 10(9) pfu/0.1 ml), AD. Egr-Smad7 + radiation group (Group RAR, receiving intratracheal instillation of AD. Egr-Smad7 of the dose of 10(9) pfu/0.1 ml and then radiation to the chest 14 h later), replication-defective adenovirus group (Group AV, receiving intratracheal instillation of replication-defective adenovirus of the dose of 10(9) pfu/0.1 ml), replication-defective adenovirus + irradiation group (Group AVR, receiving intratracheal instillation of replication-defective adenovirus of the dose of 10(9) pfu/0.1 ml and then radiation to the chest 14 h later), blank control group (Group C), and pure irradiation group (Group R), each group was re-divided into 6 subgroups of 8 mice to be observed 0, 1, 2, 4, 8, and 12 weeks after the treatment. The mice were killed at different time points and their lungs were taken out. The levels of type I collagen, type III collagen, connective tissue growth factor (CTGF), and transforming growth factor-beta1 (TGF-beta1) were detected by ELISA. The level of hydroxyproline was examined by alkaline hydrolysis method. The lung tissues were stained with HE to undergo pathological examination. RESULTS: The TGF-beta1 levels of the irradiation groups all increased, peaking in the second week (all P < 0.05), all significantly higher than those of Group C. However, the TGF-beta1 levels at different time points of Group RAR were all significantly lower then those of the other irradiation groups. The CTGF levels of different groups at different time points were all significantly higher than those of Group C (P < 0.05 or P < 0.01), and the CTGF levels of Groups RA and AV were decreased to almost normal 12 weeks after the irradiation. The levels of type I collagen and type III collagen of the 1 and 2-week subgroups of Group RAR were significantly lower than those of Group C (all P < 0.01), then gradually increased, and were slightly higher than those Group C 12 weeks later. The levels of type I collagen and type III collagen at different time points of the other groups were all significantly higher than those of Group C (P < 0.05 or P < 0.01). However, The levels of type I collagen at different time points of Group RAR were all lower than those of the other groups except Group C, and the levels of type III collagen in the first to eighth weeks after irradiation of Group RAR were all lower than those of the other groups except Group C. The hydroxyproline level of the 1 and 2 week subgroups of Group RAR were significantly lower than those of Group C (all P < 0.01), and then gradually increased. The hydroxyproline levels of the other irradiation groups all gradually increased significantly, peaking at the 12 th week (all P < 0.01). 1 approximately 2 weeks after irradiation Groups RAR, RA, and AV showed remarkable pulmonary congestion changes, even more remarkable then those in Group R, 8 approximately 12 week later, fibrosis changes were found in Group R and AVR, and 12 weeks later the histological structure of lung of Group AV, RAR, and RA returned almost normal. CONCLUSION: Radioactive rays induce Egr-1 promoter to regulated the expression of exogenous Smad7 gene that blocks the signal transduction of TGF-beta. Thus use of AD. Egr-Smad7 may become a novel strategy of gene therapy in prevention and treatment of pulmonary fibrosis.

Adenoviridae↗

PubMed2006

Orphan nuclear receptor small heterodimer partner inhibits transforming growth factor-beta signaling by repressing SMAD3 transactivation.

Orphan nuclear receptor small heterodimer partner (SHP) is an atypical member of the nuclear receptor superfamily; SHP regulates the nuclear receptor-mediated transcription of target genes but lacks a conventional DNA binding domain. In this study, we demonstrate that SHP represses transforming growth factor-beta (TGF-beta)-induced gene expression through a direct interaction with Smad, a transducer of TGF-beta signaling. Transient transfection studies demonstrate that SHP represses Smad3-induced transcription. In vivo and in vitro protein interaction assays revealed that SHP directly interacts with Smad2 and Smad3 but not with Smad4. Mapping of domains mediating the interaction between SHP and Smad3 showed that the entire N-terminal domain (1-159 amino acids) of SHP and the linker domain of Smad3 are involved in this interaction. In vitro glutathione S-transferase pulldown competition experiments revealed the SHP-mediated repression of Smad3 transactivation through competition with its co-activator p300. SHP also inhibits the activation of endogenous TGF-beta-responsive gene promoters, the p21, Smad7, and plasminogen activator inhibitor-1 (PAI-1) promoters. Moreover, adenovirus-mediated overexpression of SHP decreases PAI-1 mRNA levels, and down-regulation of SHP by a small interfering RNA increases both the transactivation of Smad3 and the PAI-1 mRNA levels. Finally, the PAI-1 gene is expressed in SHP(-/-) mouse hepatocytes at a higher level than in normal hepatocytes. Taken together, these data indicate that SHP is a novel co-regulator of Smad3, and this study provides new insights into regulation of TGF-beta signaling.

Animals↗

PubMed2006

[Effects of beta-sitosterol on microtubular systems in cervical cancer cells].

OBJECTIVE: To investigate beta-sitosterol's inhibitory effects on SiHa cells' growth, and the effects on microtubular system in SiHa cell. METHODS: Proliferation inhibition of SiHa cell line was evaluated by MTT assay. Cell cycle of SiHa cells treated with beta-sitosterol was analyzed by flow cytometry. The expression and distribution of microtubule and microtubule associated protein 2 in SiHa cells were investigated by confocal microscopy. Immunoblotting analysis was used to determine tubulin alpha, microtubule associated protein 2, and the proportion of polymerization of tubulin. RESULTS: beta-sitosterol could obviously inhibit the proliferation of SiHa cells, and induce the accumulation of cells in S phase (rather than the G2/M phase) and mitotic arrest in the cell cycle. Confocal microscopy showed an abnormal microtubular network in SiHa cell treated with beta-sitosterol for 5 days, and the expression of microtubule associated protein 2 was marked down-regulated. Further analysis by immunoblotting confirmed the down-regulation of beta-sitosterol on the expression for both microtubule associated protein 2 and tubulin alpha. Moreover, beta-sitosterol reduced the proportion of polymerization of microtubule in a time-dependent manner. CONCLUSION: beta-sitosterol could down-regulate the expression of tubulin alpha and microtubule associated protein 2 in SiHa cells, and inhibit the microtubular polymerization. Our results suggested an anti-microtubule characteristic of beta-sitosterol which might contribute to the proliferation inhibition of SiHa cells.

Cell Line, Tumor↗

PubMed2006

The p110alpha isoform of PI3K is essential for proper growth factor signaling and oncogenic transformation.

Growth factor signaling is mediated through Class IA phosphatidylinositol 3-kinases (PI3Ks). Among this class of enzymes, only p110alpha, encoded by the PIK3CA gene, has been found to be mutant in human cancers. To determine the specific functions of p110alpha, we generated mice carrying a conditionally targeted allele of the PIK3CA gene. Here, we report that PIK3CA-knockout mouse embryonic fibroblasts are deficient in cellular signaling in response to various growth factors, unable to differentiate into adipocytes, and resistant to oncogenic transformation induced by a variety of oncogenic receptor tyrosine kinases, indicating a fundamental role for p110alpha in these biological processes.

Adipocytes↗

PubMed2006

Molecular characterization of a DNA fragment harboring the replicon of pBMB165 from Bacillus thuringiensis subsp. tenebrionis.

BACKGROUND: Bacillus thuringiensis belongs to the Bacillus cereus sensu lato group of Gram-positive and spore-forming bacteria. Most isolates of B. thuringiensis can bear many endogenous plasmids, and the number and size of these plasmids can vary widely among strains or subspecies. As far as we know, the replicon of the plasmid pBMB165 is the first instance of a plasmid replicon being isolated from subsp. tenebrionis and characterized. RESULTS: A 20 kb DNA fragment containing a plasmid replicon was isolated from B. thuringiensis subsp. tenebrionis YBT-1765 and characterized. By Southern blot analysis, this replicon region was determined to be located on pBMB165, the largest detected plasmid (about 82 kb) of strain YBT-1765. Deletion analysis revealed that a replication initiation protein (Rep165), an origin of replication (ori165) and an iteron region were required for replication. In addition, two overlapping ORFs (orf6 and orf10) were found to be involved in stability control of plasmid. Sequence comparison showed that the replicon of pBMB165 was homologous to the pAMbeta1 family replicons, indicating that the pBMB165 replicon belongs to this family. The presence of five transposable elements or remnants thereof in close proximity to and within the replicon control region led us to speculate that genetic exchange and recombination are potentially responsible for the divergence among the replicons of this plasmid family. CONCLUSION: The replication and stability features of the pBMB165 from B. thuringiensis subsp. tenebrionis YBT-1765 were identified. Of particular interest is the homology and divergence shared between the pBMB165 replicon and other pAMbeta1 family replicons.

Bacillus thuringiensis↗

PubMed2006

Association analysis of NAD(P)H:quinone oxidoreductase gene 609 C/T polymorphism with Alzheimer's disease.

Alterations of the NAD(P)H:quinone oxidoreductase (NQO1) activity are associated with Alzheimer's disease (AD). A polymorphism consisting of a single nucleotide (C-->T) change at position 609 of NQO1 influences the NQO1 activity. Therefore the NQO1 C609T polymorphism may confer susceptibility for AD developing. To test the hypothesis, we have performed an association study between the NQO1 gene polymorphism C609T and late-onset Alzheimer's disease (LOAD) in Chinese population. Totally 104 LOAD patients and 128 controls were enrolled in our data set. All subjects were genotyped for NQO1 and Apolipoprotein E (APOE). There were no significant differences in NQO1 genotype or allele frequencies between cases and controls. Likewise, with the stratification of APOE psilon4 status, no statistical difference was observed between cases and controls. Our findings suggested that this polymorphism might not represent additional genetic risk factor for LOAD. However, the present study cannot exclude NQO1 as a possible candidate for LOAD. Further study in a larger population and biological functional analysis of NQO1 gene is required to verify the role of NQO1 in LOAD.

Aged↗

PubMed2006

Comparison of phage pVIII and KLH as vector in inducing the production of cytokines in C57BL/6J mice.

We have demonstrated that phage display Candida albicans (C. albicans) LKVIRK epitope was protective in systemically infected C57BL/6J mice. The different development from precursor Ths, Th1 or Th2, will result in a protective or nonprotective immune response. To compare the types of cytokines induced by biologically and chemically synthesized vectors, C57BL/6J mice were immunized with hybrid phage displaying the epitope of LKVIRK and by synthesized peptide epitope LKVIRKNIVKKMIE conjugated through cysteine to keyhole limpet haemocyanin (KLH). The production of cytokines in spleens of immunized mice and in splenocytes culture supernatants stimulated by homologous immunogen in vitro was studied by RT-PCR and quantitative sandwich ELISA. The results showed that, compared to Tris-EDTA buffer (TE, 1 mM Tris, 0.1 mM EDTA, pH 8.0) injected mice, the expressions of Th1 type cytokine IFN-gamma, IL-2 and IL-12 were increased in hybrid phage, KLH-C, and wild phage immunized mice, and there were no differences between mice immunized with hybrid phage and KLH-C. While the expression of Th2 type cytokine IL-10 was similar in all mice, IL-4 was not detected. We obtained the same results in mRNA and protein level. These findings indicated that as carriers, phage and KLH were similar in inducing the Th1 type cytokines expression. Comparing to peptide synthesis couple with a carrier protein for injection, phage may be an inexpensive and simple route to the production of effective vaccines.

Animals↗

PubMed2006

An intracellular lamellar-nonlamellar phase transition rationalizes the superior performance of some cationic lipid transfection agents.

Two cationic phospholipid derivatives with asymmetric hydrocarbon chains were synthesized: ethyl esters of oleoyldecanoyl-ethylphosphatidylcholine (C18:1/C10-EPC) and stearoyldecanoyl-ethylphosphatidylcholine (C18:0/C10-EPC). The former was 50 times more effective as a DNA transfection agent (human umbilical artery endothelial cells) than the latter, despite their similar chemical structure and virtually identical lipoplex organization. A likely reason for the superior effectiveness of C18:1/C10-EPC relative to C18:0/C10-EPC (and to many other cationic lipoids) was suggested by the phases that evolved when these lipoids were mixed with negatively charged membrane lipid formulations. The saturated C18:0/C10-EPC remained lamellar in mixtures with biomembrane-mimicking lipid formulations [e.g., dioleoyl-phosphatidylcholine/dioleoyl-phosphatidylethanolamine/dioleoyl-phosphatidylserine/cholesterol at 45:20:20:15 (wt/wt)]; in contrast, the unsaturated C18:1/C10-EPC exhibited a lamellar-nonlamellar phase transition in such mixtures, which took place at physiological temperatures, approximately 37 degrees C. As is well known, lipid vehicles exhibit maximum leakiness and contents release in the vicinity of phase transitions, especially those involving nonlamellar phase formation. Moreover, nonlamellar phase-forming compositions are frequently highly fusogenic. Indeed, FRET experiments showed that C18:1/C10-EPC exhibits lipid mixing with negatively charged membranes that is several times more extensive than that of C18:0/C10-EPC. Thus, C18:1/C10-EPC lipoplexes are likely to easily fuse with membranes, and, as a result of lipid mixing, the resultant aggregates should exhibit extensive phase coexistence and heterogeneity, thereby facilitating DNA release and leading to superior transfection efficiency. These results highlight the phase properties of the carrier lipid/cellular lipid mixtures as a decisive factor for transfection success and suggest a strategy for the rational design of superior cationic lipid carriers.

Animals↗

PubMed2006

A therapeutic target for prostate cancer based on angiogenin-stimulated angiogenesis and cancer cell proliferation.

Human angiogenin is progressively up-regulated in the prostate epithelial cells during the development of prostate cancer from prostate intraepithelial neoplasia (PIN) to invasive adenocarcinoma. Mouse angiogenin is the most up-regulated gene in AKT-induced PIN in prostate-restricted AKT transgenic mice. These results prompted us to study the role that angiogenin plays in prostate cancer. Here, we report that, in addition to its well established role in mediating angiogenesis, angiogenin also directly stimulates prostate cancer cell proliferation. Angiogenin undergoes nuclear translocation in PC-3 human prostate cancer cells grown both in vitro and in mice. Thus, knocking down angiogenin expression in PC-3 human prostate adenocarcinoma cells inhibits ribosomal RNA transcription, in vitro cell proliferation, colony formation in soft agar, and xenograft growth in athymic mice. Blockade of nuclear translocation of angiogenin by the aminoglycoside antibiotic neomycin inhibited PC-3 cell tumor growth in athymic mice and was accompanied by a decrease in both cancer cell proliferation and angiogenesis. These results suggest that angiogenin has a dual effect, angiogenesis and cancer cell proliferation, in prostate cancer and may serve as a molecular target for drug development. Blocking nuclear translocation of angiogenin could have a combined benefit of antiangiogenesis and chemotherapy in treating prostate cancer.

Animals↗