ECV304 Cells Research Articles

Enzymatic preparation of κ-carrageenan oligosaccharides and their anti-angiogenic activity

The mixture of κ-neocarrabiose-sulfate, κ-neocarrahexaose-sulfate and κ-neocarraoctaose-sulfate were prepared from κ-carrageenan with enzyme. The anti-tumor and anti-angiogenic activity of obtained κ-carrageenan oligosaccharides (KOS), were explored. The results showed that KOS could inhibit the proliferation, migration and tube formation of ECV304 cells, and could inhibit the growth of new vessels in CAM model. KOS displayed strong anti-tumor activity in both S180 and MCF-7 xenograft models. Only human CD105 was detected in MCF-7 xenograft tumor, moreover KOS could decrease the growing of new blood vessels derived from tumor cell. Real-time PCR results showed that KOS could suppress the mRNA expression of human VEGF, bFGF, bFGFR and CD105 in MCF-7 xenograft tumor. All these results indicated that KOS has anti-tumor and anti-angiogenic activity in vivo and in vitro. Especially K has the potency to inhibit the differentiation of tumor cell to blood vessel endothelial cell.

Resveratrol protects against vinorelbine-induced vascular endothelial cell injury

Vinorebine (VNR), a second-generation vinca alkaloid antitumor drug, caused serious local venous toxicities, such as venous irritation, phlebitis and necrotizing vasculitis. This study investigated whether resveratrol (RES), a naturally occurring polyphenol compound, could reduce the vascular injury induced by VNR. Human vascular endothelial cell line ECV-304 cells were exposed to VNR for 10 min and then cells were cultured with serum-free medium with or without RES for 24 h. MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphe-nyl-2-tetrazolium bromide) assay was used to detect the cell viability. Reactive oxygen species (ROS) was measured with 2′, 7′-dichlorofluorescein diacetate (DCFH-DA). The activity of superoxide dismutase (SOD) was assessed by SOD detection kit. VNR decreased the viability of ECV-304 cells in a dose-dependent manner. Moreover, VNR caused cell apoptosis, the generation of intracellular ROS and the reduction of intracellular SOD. Interestingly, pretreatment with RES for 2 h increased the cell viability in a dose-dependent manner. Cell apoptosis, the intracellular ROS generation and the reduction of intracellular SOD induced by VNR were also attenuated when cells were pretreated with RES for 2 h. These results demonstrated that RES would protect against vascular endothelial cell injury induced by VNR. So the use of RES together with VNR may be a possible therapeutic approach to avoid the vascular injury induced by VNR.

The influence of saponins on cell membrane cholesterol

We studied the influence of structurally different saponins on the cholesterol content of cellular membranes. Therefore a cell culture model using ECV-304 urinary bladder carcinoma cells was developed. To measure the cholesterol content we used radiolabeled 3H-cholesterol which is chemically and physiologically identical to natural cholesterol. The cells were pre-incubated with 3H-cholesterol and after a medium change, they were treated with saponins to assess a saponin-induced cholesterol liberation from the cell membrane. In another experiment the cells were pre-incubated with saponins and after a medium change, they were treated with 3H-cholesterol to assess a saponin-induced inhibition of cholesterol uptake into the cell membrane. Furthermore, the membrane toxicity of all applied saponins was analyzed using extracellular LDH quantification and the general cytotoxicity was analyzed using a colorimetric MTT-assay and DNA quantification. Our results revealed a correlation between membrane toxicity and general cytotoxicity. We also compared the results from the experiments on the saponin-induced cholesterol liberation as well as the saponin-induced inhibition of cholesterol uptake with the membrane toxicity. A significant reduction in the cell membrane cholesterol content was noted for those saponins who showed membrane toxicity (IC50 <60μM). These potent membrane toxic saponins either liberated 3H-cholesterol from intact cell membranes or blocked the integration of supplemented 3H-cholesterol into the cell membrane. Saponins with little influence on the cell membrane (IC50 >100μM) insignificantly altered the cell membrane cholesterol content. The results suggested that the general cytotoxicity of saponins is mainly dependent on their membrane toxicity and that the membrane toxicity might be caused by the loss of cholesterol from the cell membrane.We also analyzed the influence of a significantly membrane toxic saponin on the cholesterol content of intracellular membranes such as those of endosomes and lysosomes. In these experiments ECV-304 cells were either incubated with 3H-cholesterol or with 3H-cholesterol and 5μM saponin. After isolation of the endosomes/lysosomes their 3H-cholesterol content was measured. A significant influence of the saponins on the cholesterol content of endosomal/lysosomal membranes was not detected.

Global analysis of differential expressed genes in ECV304 Endothelial-like cells infected with human cytomegalovirus.

Human cytomegalovirus (HCMV) is a virus which has the potential to alter cellular gene expression through multiple mechanisms. With the application of DNA microarrays, we could monitor the effects of pathogens on host-cell gene expression programmes in great depth and on a broad scale. Changes in mRNA expression levels of human endothelial-like ECV304 cells following infection with human cytomegalovirus AD169 strain was analyzed by a microarray system comprising 21073 60-mer oligonucleotide probes which represent 18716 human genes or transcripts. The results from cDNA microarray showed that there were 559 differential expressed genes consisted of 471 upregulated genes and 88 down-regulated genes. Real-time qPCR was performed to validate the expression of 6 selected genes (RPS24, MGC8721, SLC27A3, MST4, TRAF2 and LRRC28), and the results of which were consistent with those from the microarray. Among 237 biology processes, 39 biology processes were found to be related significantly to HCMV-infection. The signal transduction is the most significant biological process with the lowest p value (p=0.005) among all biological process which involved in response to HCMV infection. Several of these gene products might play key roles in virus-induced pathogenesis. These findings may help to elucidate the pathogenic mechanisms of HCMV caused diseases.

The Effect of Plant Polyphenol Genistein on Migration of Endothelial Cells Induced by Human Ovarian Carcinoma Cell Line SKOV3

Angiogenesis is crucial for tumor progression and and migration of endothelial cells into tumor is important in the formation of new blood vessels in tumors. In this study we investigated the effect of Genistein on migration of human endothelial cells ECV-304 induced by human ovarian serous cystadenocarcinoma cell line SKOV3, and explored the mechanism of anti-angiogenesis of Genistein. Millicell chamber and coculture method were used to observe the influence on migration of ECV-304 induced by SKOV3 cells or its conditioned medium. The expression of angiogenesis associated protein VEGFbFGF and TGFβ-1 were determined using immunocytochemical assay. The results showed that either SKOV3 cells or its conditioned medium could induce the committed chemotactic migration of ECV-304. The chemotactic migrations of ECV-304 induced by SKOV3 or its conditioned medium were significantly inhibited by Genistein in a dose-dependent manner. 20μmol/L Genistein could down-regulate the expression of bFGF, and up-regulate the expression of TGFβ-1. Migrations of ECV-304 induced by SKOV3 or its conditioned medium are apparently inhibited by Genistein. It suggests that this inhibitory effect of Genistein is completed by down-regulating the expression of vessel growth-promoting factor bFGF, and up-regulating the expression of negative regulator TGFβ-1. This may be one of the mechanisms of anti-angiogenesis of Genistein.

Steroidal saponins from the flowers of Dioscorea bulbifera var. sativa

Eleven steroidal saponins, dioscoreanosides A-K, along with five known congeners, were isolated from the flowers of Dioscorea bulbifera var. sativa. Their structures were established by extensive NMR experiments in conjunction with mass spectrometry. The isolated compounds were tested for cytotoxicity against urinary bladder carcinoma cells (ECV-304 cells). Our results revealed a moderate activity for spiroconazol A (15), pennogenin 3-O-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranoside (12), and 26-O-ß-d-glucopyranosyl-(25R)-5-en-furost-3ß,17α,22α,26-tetraol-3-O-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranoside (13).

Microstructure, mechanical property, biodegradation behavior, and biocompatibility of biodegradable Fe–Fe2O3 composites

In this study, the effects of Fe2O3 (addition, 2, 5, 10, and 50 wt %) on the microstructure, mechanical properties, corrosion behaviors, and in vitro biocompatibility of Fe-Fe2O3 composites fabricated by spark plasma sintering were systematically investigated as a novel-structure biodegradable metallic material. The results of X-ray diffraction analysis and optical microscopy indicated that Fe-Fe2O3 composite is composed of α-Fe and FeO instead of Fe2O3. Both eletrochemical measurements and immersion test showed a faster degradation rate of Fe-2Fe2O3 and Fe-5Fe2O3 composites than pure iron and Fe-5Fe2O3 exhibited the fastest corrosion rate among these composites. Besides, the effect of Fe2O3 on the corrosion behavior of Fe-Fe2O3 composites was discussed. The extracts of Fe-Fe2O3 composite exhibited no cytotoxicity to both ECV304 and L929 cells, whereas greatly reduced cell viabilities of vascular smooth muscle cells. In addition, good hemocompatibility of all Fe-Fe2O3 composites and pure iron was obtained. To sum up, Fe-5Fe2O3 composite is a promising alternative for biodegradable stent material with elevated corrosion rate, enhanced mechanical properties, as well as excellent biocompatibility.

Staphylococcal enterotoxin B and α-toxin induce the apoptosis of ECV304 cells via similar mechanisms

Staphylococcal enterotoxin B (SEB) and α‑toxin produced by Staphylococcus aureus (S. aureus) are important in the pathogenesis of diseases. In the present study, we investigated the effects of SEB and α‑toxin on ECV304 cells. It was identified that both SEB and α‑toxin were capable of inducing the apoptosis of ECV304 cells in a dose‑ and time‑dependent manner. In addition, SEB and α‑toxin were able to induce the expression of TNF‑α and the activation of caspase‑3 and ‑8 in the ECV304 cells. The inhibition of TNF‑α (with its neutralizing antibody) and caspase‑3 and ‑8 [with the corresponding inhibitory peptides; z-N-acetyl-Asp-Glu-Val-Asp-aminomethyl-coumarin (DEVD)-fluoromethyl ketone (FMK) for inhibition of caspase‑3 and z-N-acetyl-Ile-Glu-Thr-Asp (IETD)-FMK) for inhibition of caspase‑8] significantly decreased the rates of cell apoptosis induced by SEB and α‑toxin, but was not able to completely block the induced cell apoptosis. These data suggest that SEB and α‑toxin induce ECV304 cell apoptosis via a similar mechanism, which is partially mediated by the extrinsic death pathway involving TNF‑α and caspase‑8. These results provide insights into the synergistic pathogenicity of SEB and α‑toxin during S. aureus infection.

Ruthenium (II) polypyridyl complexes stabilize the bcl-2 promoter quadruplex and induce apoptosis of Hela tumor cells

In the present study, the interaction between GC-rich sequence of bcl-2 gene P1 promoter (Pu39) and two ruthenium (II) polypyridyl complexes, [Ru(bpy)₂(tip)]²⁺ (1) and [Ru(phen)₂(tip)]²⁺ (2), was investigated by UV-Visible, fluorescence spectroscopy, circular dichroism, fluorescence resonance energy transfer melting assay and polymerase chain reaction stop assay. Those experimental results indicated that the two complexes can effectively stabilize the G-quadruplex of Pu39. It was found that the complex 2 exhibited greater cytotoxic activity than 1 against human Hela cells and can enter into Hela cells in a short period of time to effectively induce apoptosis of cells. Further experiments found that complexes 1 and 2 had as potent inhibitory effects on ECV-304 cell migration as suramin. Those noteworthy results provide new insights into the development of anticancer agents for targeting G-quadruplex DNA.

Comparative in vitro Study on Pure Metals (Fe, Mn, Mg, Zn and W) as Biodegradable Metals

Five pure metals including Fe, Mn, Mg, Zn and W have been investigated on their corrosion behavior and in vitro biocompatibility by electrochemical measurement, static immersion test, contact angle measurement, cytotoxicity and hemocompatibility tests. It is found that the sequence of corrosion rate of five metals in Hank's solution from high to low is: Mg > Fe > Zn > Mn > W. Fe, Mg and W show no cytotoxicity to L929 and ECV304 cells, Mn induces significant cytotoxicity to both L929 and ECV304 cells, and Zn has almost no inhibition effect on the metabolic activities of ECV304 while largely reduces the cell viability of L929 cells. The hemolysis percentage of five pure metals is lower than 5% except for Mg and platelets adhered on Zn has been activated and pseudopodia-like structures can be observed while platelets on the other four metals keep normal.

AEG-1 overexpression is essential for maintenance of malignant state in human AML cells via up-regulation of Akt1 mediated by AURKA activation

Acute myeloid leukemia (AML) remains highly fatal, highlighting the need for improved understanding of signal pathways that can lead to the development of new therapeutic regimens targeting common molecular pathways shared across different AML subtypes. Here we demonstrate that astrocyte elevated gene-1 (AEG-1) is one of such pathways, involving in cell cycle and apoptosis regulation and contributing to enhanced proliferation and chemoresistance in HL-60 and U937 AML cells. The pleiotropic effects of AEG-1 on AML were found to correlate with two novel target genes, Aurora kinase A (AURKA) and Akt1. Down-regulation of AEG-1 by short-hairpin RNA (shRNA) could not only decrease AURKA expression both on mRNA and protein levels but also decrease the levels of pAkt473 and pAkt308 (the active forms of phosphorylated Akt), similar effect as using AURKA inhibitor Tozasertib (VX680). Furthermore, the AEG-1 shRNA-induced malignant phenotype changes could be mitigated by forced overexpression of AURKA through increased Akt1 activation and phosphorylation in AML cells. On the other hand, although exogenous expression of AEG-1 could increase both AURKA and Akt expression levels the simultaneous use of AURKA inhibitor Tozasertib blocked AEG-1's role of up-regulation of Akt expression in ECV304 cells, suggesting that AURKA might be a key mediator of AEG-1 in regulating Akt activation, and a key effector of AEG-1 in maintaining the malignant state of AML. Moreover, knockdown AEG-1 expression also changed the expression levels of PTEN, survivin and stathmin, the genes that have been reported to be involved in the development of several other malignant tumors. Our results provide evidence for AEG-1's carcinogenesis role in AML and reveal a novel functional link between AEG-1 and AURKA on Akt1 activation. AEG-1 can be an important candidate as a drug design target within AURKA signal pathway for more specific killing of AML cells while sparing normal cells.

The effects of substrate roughness and associated surface properties on the biocompatibility of diamond-like carbon films

Diamond-like carbon (DLC) films have many excellent properties such as high hardness, low friction coefficient, chemical inertness, and biocompatibility. Their good biocompatibility is a result of their chemical composition containing only carbon and hydrogen which are biologically compatible. Previous studies on biocompatibility of DLC films focus primarily on morphological issues like roughness and wettability. However, we believe that the stress and the associated surface properties in the films are equally important. In exploring these effects, the silicon substrates were roughened with 30wt.% KOH in different etching time. The substrate roughness was increased by longer etching time. Three different types of samples – silicon without DLC film, smooth silicon with DLC thin film and rough silicon with DLC – were prepared by culturing the human endothelial cell ECV304 for 72h. The DLC films were examined by AFM, Raman spectroscopy, XPS, sessile drop and surfcorder to study the morphology, chemical bonding, wettability and residual stress. For DLC surface properties, as the substrate roughness increases, the residual stress increases and the sp3/sp2 ratio decreases. Meanwhile, the surface became more hydrophobic. The stress caused by the substrate roughness seems to be correlated with the surface properties of DLC. As for the ECV304 cell culture, the viability for bare silicon without DLC is almost zero. This indicates that silicon is not biocompatible for ECV 304. The cell number of ECV in DLC/rough substrate is less than that in DLC/smooth substrate in a 72-hour cell culture. This implies that a DLC/Si whose surface properties are associated with higher stress is adverse to ECV cell culture.

Methylglyoxal induces DNA crosslinks in ECV304 cells via a reactive oxygen species-independent protein carbonylation pathway

Methylglyoxal (MG) is a reactive dicarbonyl compound that is produced endogenously from glycolytic intermediates and via gluconeogenesis. Elevated MG levels in diabetes patients are believed to cause diabetic complications. MG-induced crosslinking products from the covalent binding of DNA or protein alone or together could be relevant to carcinogenesis and multiple complications in diabetes. However, the mechanisms governing DNA crosslink formation by MG are unclear. We investigated whether MG could induce DNA crosslinks in human ECV304 cells and the possible mechanism of this action. The level of DNA crosslinks and reactive oxygen species production were assayed by a modified alkaline Comet assay and a 2′,7′ dichlorofluorescin diacetate (DCHF-DA) assay, respectively. MG caused a time- and dose-dependent increase in DNA crosslinks and a dose-dependent increase in protein carbonylation in ECV304 cells. Addition of 2mM MG resulted in a transient increase in protein carbonylation, and this increase peaked within 2h and then rapidly decreased. Most notably, MG did not cause significantly enhanced ROS generation in ECV304 cells. Co-treatment with carbonyl-scavenging drugs, such as aminoguanidine, N-acetyl-l-cysteine, and glutathione, significantly inhibited the formation of DNA crosslinks by MG, whereas co-treatment with the antioxidant ascorbic acid did not. In conclusion, our results imply that MG induces DNA crosslink formation in ECV304 cells via a reactive oxygen species-independent protein carbonylation pathway. Our findings also suggest that non-toxic aminothiol antioxidants with carbonyl scavenging capabilities are potential therapeutic agent for MG-related diseases, such as diabetes and neurodegeneration. Furthermore, our findings also imply that DNA nonbinding proteins, bovine serum albumin might be able to crosslink calf thymus DNA in the presence of MG.

Taxonomic Identification and Bioactivity Screening of the Symbiotic Bacteria Strains of &lt;i&gt;Euphausia superba&lt;/i&gt; from Antarctic Ocean

The marine symbiotic bacteria strains were isolated from the Antarctic krill (Euphausia superb) samples captured in Antarctica Ocean. The taxonomic identification was then performed. The screening of the bioactivity against nitric oxide (NO) release for the crude extract after the strain fermentation and cell culture extraction were finally carried out. The taxonomic identification analysis showed the strain was very close to Salegentibacter salinus ISL with the similarity value of 94.5% based on 16S rDNA gene sequencing and homology analysis. According to the analysis, this strain was identified as a new strain and nominated as Salegentibacter sp. NJ-102. The bioactivity screening analysis of the culture extract demonstrated the crude extract showed significant inhibitory bioactivity against NO release and the expression of the inducible nitric oxide synthase (iNOS) in the ECV-304 cells.

Metallofullerol Nanoparticles with Low Toxicity Inhibit Tumor Growth by Induction of G0/G1 Arrest

[Gd@C(82)(OH)(22)](n) is a new type of nanoparticle with potent antineoplastic activity and low toxicity compared with traditional drugs. In this study, we explored, for the first time, the effect of [Gd@C(82)(OH)(22)](n) on the cell cycle using human breast cancer MCF-7 and human umbilical vein endothelial ECV304 cell lines by flow cytometry. Cell viability was assessed through CCK-8 assay, and MCF-7 tumor-bearing mice were examined after 2 weeks of treatment with [Gd@C(82)(OH)(22)](n). Cell cycle-related gene expression was detected by microarray and confirmed by real-time PCR and RNAi. Cell viability studies confirmed that [Gd@C(82)(OH)(22)](n) inhibits breast cancer effectively with very low toxicity. Flow cytometric data and microarray results reveal that [Gd@C(82)(OH)(22)](n) mediates G0/G1 arrest in both cell lines by regulating the expression of several genes, such as cyclin D2, cyclin E and CDK4, among others, in the related cell cycle. Results further demonstrated that [Gd@C(82)(OH)(22)](n) could inhibit tumor growth by inducing tumor cell and vein endothelial cell G0/G1 arrest, which may explain the low toxicity of [Gd@C(82)(OH)(22)](n).

Identification and characterization of a 43 kDa actin protein involved in the DENV-2 binding and infection of ECV304 cells

Characterization of the primary host factors associated with host–virus interaction is critical for understanding how a virus infects its host cell. In this study, a modified virus overlay protein binding assay was developed. Host factors with 34, 43, and 55 kDa proteins, which could interact with EDIII, a cell receptor-binding domain of Dengue virus (DENV)-enveloped E protein, were isolated from ECV304 cells. Mass spectrometry identified peptide masses of 43 kDa protein matched to actin, a cytoskeleton protein in eukaryotic cells. The interaction between 43 kDa actin and DENV-2 EDIII was further confirmed by competitive blocking and co-immunoprecipitation assays. Actin cytoskeleton rearrangement was observed within 1 h p.i. of DENV-2-infected ECV304 cells in the confocal immunofluorescent assay. The co-localization of DENV-2 E protein with the actin filaments occurred in the late stage of the DENV replication cycle. Finally, a docking complex was constructed, and the functional residues involved in the interaction of actin and DENV-2 EDIII protein were predicted. Our findings suggest that the direct contact of DENV E protein with 43 kDa actin protein may have a crucial function in DENV infection of ECV304 cells.

In vitro study on newly designed biodegradable Fe‐X composites (X = W, CNT) prepared by spark plasma sintering

Early in vivo animal test on pure iron coronary stent had proved that it is a promising candidate material as biodegradable metal, despite a faster degradation rate and uniform degradation mode is expected. In this work, Fe-X (X= W, CNT) composites were prepared from powders of pure iron and the additive secondary phase X using the spark plasma sintering (SPS) method, aiming to obtain a higher corrosion rate and a more uniform corrosion mode in physiological environment. The microstructures, mechanical properties, corrosion behaviors, and in vitro biocompatibility of these Fe-X composites were investigated. It was found that the additives were uniformly distributed in the iron matrix and relatively high dense Fe-X composite bulk samples were obtained after sintering by SPS. Both the yield strength and ultimate compressive strength increased when compared with that of as-cast pure iron. The corrosion mode of Fe-X composites turned out to be uniform corrosion instead of localized corrosion. Electrochemical measurements and immersion tests indicated that the addition of W and CNT could increase the corrosion rate of the iron matrix. From the results of cytotoxicity evaluation, it was found that all the Fe-X composites extracts induced no obvious cytotoxicity to L929 cells and ECV304 cells whereas significantly decreased cell viabilities of VSMC cells. The hemocompatibility tests showed that all the hemolysis percentage of Fe-X composites were less than 5%, and no sign of thrombogenicity was observed. It might be concluded that Fe composited with suitable second phase can exhibit higher strength, faster degradation rate, and uniform degradation mode than those of pure iron and are promising candidates for future development of new degradable metallic stents.

Nanog suppresses cell migration by downregulating thymosin β4 and Rnd3

Nanog, Sox2, and Oct4 are key transcription factors critical for the pluripotency and self-renewal of embryonic stem (ES) cells. Their downregulations lead to differentiation, accompanied with changes in cell motility. Whether these factors impact cell motility directly, however, is not clear. Here we addressed this question by initially assessing their effect in non-stem cells. We found that the ectopic expression of Nanog, Sox2, or Oct4 markedly inhibited ECV304 cell migration. Detailed examinations revealed that Nanog induced disorganizations of the actin cytoskeleton and peripheral localizations of focal adhesions. These effects required its DNA-binding domain and are thus transcription dependent. Furthermore, thymosin β4 and Rnd3 were identified as its downstream targets. Their depletions in ECV304 cells by RNAi phenocopied the ectopic expression of Nanog in both cell motility and actin organization, whereas their ectopic expressions rescued the migration defect of Nanog overexpression. Both proteins were upregulated during mouse ES cell differentiation. Their levels in the pluripotent mouse P19 cells also increased upon Nanog ablation, coincident with an increase in cell motility. Moreover, persistent expression of Nanog in zebrafish embryos suppressed gastrulation and cell migration. These results indeed suggest a dual role of certain transcription factors in the orchestration of differentiation and motility.

Effect of Tumstatin T-7 Peptide on HepG-2 Cells and Human Umbilical Vein Endothelial Cells

The direct anti-tumor T-7 peptide of tumstatin was obtained to study its effect on human hepatoma cells (HepG-2) and human umbilical vein endothelial cells (ECV304). T-7 peptide was synthesized and its purity was up to 98.5%. MTT assay, growth curve, transmission electron microscopy(TEM) were used to detect the proliferation inhibition and pro-apoptotic function. MTT experiments and growth curve experiments showed that the survival of human hepatoma cells (HepG-2) decreased in a time- and dose-dependent way with the concentration of T-7 peptide increased. T-7 peptide can induce apoptosis of HepG-2 significantly. Apoptosis features were observed by TEM. However, the inhibition of T-7 peptide on human umbilical vein endothelial cells (ECV304) was weaker. Experiments showed thatT-7 peptide can affect HepG-2 cells. It had a certain therapeutic effect on human hepatocellular carcinoma. T-7 peptide have little effect on ECV304 cells, which means it didn’t influence the formation of tumor angiogenesis and normal cells

High In Vitro Infectivity of a Doxycycline-Insensitive Strain of Orientia tsutsugamushi.

We compared the infectivity and growth rates of 12 strains of Orientia tsutsugamushi in a cell culture system. ECV304 cells were infected with O. tsutsugamushi strains for 4 hr, and the culture was maintained for 72 hr. Immunofluorescence (IF) staining was performed at 4, 24, 48, and 72 hr after inoculation (hpi), and IF-positive foci were enumerated. The AFSC-4 strain, which is known to be insensitive to doxycycline, showed higher numbers of IF-positive foci than the other 11 strains at 4, 24, 48, and 72 hpi, which may explain its apparent insensitivity to antibiotics.