Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 22
Filter
Add more filters










Publication year range
1.
Integr Cancer Ther ; 16(3): 319-328, 2017 09.
Article in English | MEDLINE | ID: mdl-27252074

ABSTRACT

BACKGROUND: The Chinese herbal mixture, Tien-Hsien liquid (THL), has been used as an anticancer dietary supplement for more than 20 years. Our previous studies have shown that THL can modulate immune responseand inhibit tumor growth. In this study, we further evaluated the effect of THL on anticancer immune response in mice vaccinated with γ-ray-irradiated tumor cells. METHODS: The antitumor effect of THL was determined in mice vaccinated with low-tumorigenic CT-26-low colon cancer cells or γ-ray-irradiated high-tumorigenic CT-26-high colon cancer cells. The number of natural killer (NK) cells and T lymphocytes in the spleen was analyzed by flow cytometry. The tumor-killing activities of NK cells and cytotoxic T lymphocytes (CTLs) were analyzed by flow cytometry using YAC-1 and CT-26-high cells, respectively, as target cells. The levels of IFN-γ, IL-2, and TNF-α were determined by ELISA. RESULTS: THL suppressed the growth of CT-26-high tumor in mice previously vaccinated with low-tumorigenic CT-26-low cells or γ-irradiated CT-26-high cells. THL increased the populations of NK cells and CD4+ T lymphocytes in the spleen and enhanced the tumor-killing activities of NK cells and CTL in mice vaccinated with γ-irradiated CT-26-high cells. THL increased the production of IFN-γ, IL-2, and TNF-α in mice vaccinated with γ-irradiated CT-26-high cells. CONCLUSION: THL can enhance the antitumor immune responses in mice vaccinated with killed tumor cells. These results suggest that THL may be used as a complementary medicine for cancer patients previously treated with killed tumor cell vaccines, radiotherapy, or chemotherapy.


Subject(s)
Antineoplastic Agents/pharmacology , Colonic Neoplasms/drug therapy , Drugs, Chinese Herbal/pharmacology , Immunity/drug effects , Animals , Cell Line, Tumor , Colonic Neoplasms/immunology , Colonic Neoplasms/metabolism , Female , Interferon-gamma/metabolism , Interleukin-2/metabolism , Killer Cells, Natural/drug effects , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Mice , Mice, Inbred BALB C , T-Lymphocytes, Cytotoxic/drug effects , T-Lymphocytes, Cytotoxic/immunology , T-Lymphocytes, Cytotoxic/metabolism , Tumor Necrosis Factor-alpha/metabolism
2.
PLoS One ; 10(8): e0133910, 2015.
Article in English | MEDLINE | ID: mdl-26263554

ABSTRACT

BACKGROUND: Human infections with avian influenza viruses (AIVs) have frequently raised global concerns of emerging, interspecies-transmissible viruses with pandemic potential. Waterfowl, the predominant reservoir of influenza viruses in nature, harbor precursors of different genetic lineages that have contributed to novel pandemic influenza viruses in the past. METHODS: Two duck influenza H5N2 viruses, DV518 and DV413, isolated through virological surveillance at a live-poultry market in Taiwan, showed phylogenetic relatedness but exhibited different replication capabilities in mammalian Madin-Darby Canine Kidney (MDCK) cells. This study characterizes the replication properties of the two duck H5N2 viruses and the determinants involved. RESULTS: The DV518 virus replicated more efficiently than DV413 in both MDCK and chicken DF1 cells. Interestingly, the infection of MDCK cells by DV518 formed heterogeneous plaques with great differences in size [large (L) and small (S)], and the two viral strains (p518-L and p518-S) obtained from plaque purification exhibited distinguishable replication kinetics in MDCK cells. Nonetheless, both plaque-purified DV518 strains still maintained their growth advantages over the plaque-purified p413 strain. Moreover, three amino acid substitutions in PA (P224S), PB2 (E72D), and M1 (A128T) were identified in intra-duck variations (p518-L vs p518-S), whereas other changes in HA (N170D), NA (I56T), and NP (Y289H) were present in inter-duck variations (DV518 vs DV413). Both p518-L and p518-S strains had the N170D substitution in HA, which might be related to their greater binding to MDCK cells. Additionally, polymerase activity assays on 293T cells demonstrated the role of vRNP in modulating the replication capability of the duck p518-L viruses in mammalian cells. CONCLUSION: These results demonstrate that intra-host phenotypic variation occurs even within an individual duck. In view of recent human infections by low pathogenic AIVs, this study suggests possible determinants involved in the stepwise selection of virus variants from the duck influenza virus population which may facilitate inter-species transmission.


Subject(s)
Ducks , Genotype , Influenza A Virus, H5N2 Subtype/physiology , Influenza in Birds/virology , Phenotype , Amino Acid Sequence , Amino Acid Substitution , Animals , Biological Evolution , Cell Line , Cells, Cultured , Chick Embryo , Genetic Variation , Genome, Viral , Humans , Influenza A Virus, H5N2 Subtype/isolation & purification , Taiwan , Viral Plaque Assay , Viral Proteins/chemistry , Viral Proteins/genetics , Virus Replication
3.
BMC Complement Altern Med ; 14: 194, 2014 Jun 18.
Article in English | MEDLINE | ID: mdl-24939647

ABSTRACT

BACKGROUND: Isoflavone-containing soy products modulate allergic inflammation in mice. In our previously study, IFN-γ and IL-10 production increased in mice fed with Saccharomyces cerevisiae legume fermented product (SCLFP), demonstrating that SCLFP had immunomodulatory activity. In this study, we tested the anti-inflammatory effects of SCLFP in a mouse model of cutaneous atopic dermatitis inflammation induced by epicutaneous sensitization. METHODS: Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2-dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. The thickness of the skin epithelium, eosinophil migration, and T helper responses were determined in patched skin and draining lymph nodes of mice fed with and without SCLFP. RESULTS: Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2-dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. SCLFP feeding attenuated this cutaneous Th2 response, as evidenced by decreased thickening of the epidermis, less eosinophil infiltration, and lower levels of IL-5, IL-13, and CXCL11 expression compared to controls. Oral administration of SCLFP also modulated Th1 responses in draining lymph nodes, with lower levels of IFN-γ, IL-4, and IL-17 expression. CONCLUSION: Oral intake of SCLFP modulated the induced Th2 inflammatory responses in skin and might have potential applications for the prevention and treatment of atopic dermatitis.


Subject(s)
Dermatitis, Atopic/drug therapy , Fabaceae/metabolism , Immunologic Factors/pharmacology , Plant Extracts/pharmacology , Saccharomyces cerevisiae/metabolism , Allergens/immunology , Allergens/metabolism , Animals , Dermatitis, Atopic/immunology , Dermatitis, Atopic/metabolism , Disease Models, Animal , Enterotoxins/immunology , Enterotoxins/pharmacology , Fabaceae/chemistry , Fabaceae/microbiology , Female , Fermentation , Immunologic Factors/chemistry , Immunologic Factors/immunology , Immunologic Factors/metabolism , Interleukins/immunology , Interleukins/metabolism , Mice , Mice, Inbred BALB C , Plant Extracts/chemistry , Plant Extracts/immunology , Plant Extracts/metabolism , Skin/immunology , Skin/metabolism , Th2 Cells/drug effects , Th2 Cells/immunology
4.
PLoS One ; 8(12): e82254, 2013.
Article in English | MEDLINE | ID: mdl-24340011

ABSTRACT

Endocan (or called Esm-1) has been shown to have tumorigenic activities and its expression is associated with poor prognosis in various cancers. Latent membrane protein 1 (LMP1) is an Epstein-Barr virus (EBV)-encoded oncoprotein and has been shown to play an important role in the pathogenesis of EBV-associated nasopharyngeal carcinoma (NPC). To further understand the role of LMP1 in the pathogenesis of NPC, microarray analysis of LMP1-regulated genes in epithelial cells was performed. We found that endocan was one of the major cellular genes upregulated by LMP1. This induction of endocan by LMP1 was confirmed in several epithelial cell lines including an NPC cell line. Upregulation of endocan by LMP1 was found to be mediated through the CTAR1 and CTAR2 domains of LMP1 and through the LMP1-activated NF-κB, MEK-ERK and JNK signaling pathways. To study whether endocan was expressed in NPC and whether endocan expression was associated with LMP1 expression in NPC, the expression of endocan and LMP1 in tumor tissues from 42 NPC patients was evaluated by immunohistochemistry. Expression of endocan was found in 52% of NPC specimens. Significant correlation between LMP1 and endocan expression was observed (p<0.0001). Moreover, NPC patients with endocan expression were found to have a shorter survival than NPC patients without endocan expression (p=0.0104, log-rank test). Univariate and Multivariate analyses revealed that endocan was a potential prognostic factor for NPC. Finally, we demonstrated that endocan could stimulate the migration and invasion ability of endothelial cells and this activity of endocan was dependent on the glycan moiety and the phenylalanine-rich region of endocan. Together, these studies not only identify a new molecular marker that may predict the survival of NPC patients but also provide a new insight to the pathogenesis of NPC.


Subject(s)
Epstein-Barr Virus Infections , Gene Expression Regulation, Neoplastic , Gene Expression Regulation, Viral , Herpesvirus 4, Human , Nasopharyngeal Neoplasms , Neoplasm Proteins/biosynthesis , Proteoglycans/biosynthesis , Up-Regulation , Viral Matrix Proteins/biosynthesis , Adolescent , Adult , Aged , Carcinoma , Disease-Free Survival , Epstein-Barr Virus Infections/metabolism , Epstein-Barr Virus Infections/mortality , Epstein-Barr Virus Infections/pathology , Female , Humans , Male , Middle Aged , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms/metabolism , Nasopharyngeal Neoplasms/mortality , Nasopharyngeal Neoplasms/pathology , Nasopharyngeal Neoplasms/virology , Survival Rate
5.
J Virol ; 87(1): 110-23, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23055567

ABSTRACT

Transcription and replication of the influenza A virus RNA genome occur in the nucleus through the viral RNA-dependent RNA polymerase consisting of PB1, PB2, and PA. Cellular factors that associate with the viral polymerase complex play important roles in these processes. To look for cellular factors that could associate with influenza A virus PA protein, we have carried out a yeast two-hybrid screen using a HeLa cell cDNA library. We identified six cellular proteins that may interact with PA. We focused our study on one of the new PA-interacting proteins, HAX1, a protein with antiapoptotic function. By using glutathione S-transferase pulldown and coimmunoprecipitation assays, we demonstrate that HAX1 specifically interacts with PA in vitro and in vivo and that HAX1 interacts with the nuclear localization signal domain of PA. Nuclear accumulation of PA was increased in HAX1-knockdown cells, and this phenotype could be reversed by reexpression of HAX1, indicating that HAX1 can impede nuclear transport of PA. As a consequence, knockdown of HAX1 resulted in a significant increase in virus yield and polymerase activity in a minigenome assay, and this phenotype could be reversed by reexpression of HAX1, indicating that HAX1 can inhibit influenza A virus propagation. Together, these results not only provide insight into the mechanism underlying nuclear transport of PA but also identify an intrinsic host factor that restricts influenza A virus infection.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Host-Pathogen Interactions , Influenza A virus/enzymology , Protein Interaction Mapping , RNA-Dependent RNA Polymerase/metabolism , Viral Proteins/metabolism , Active Transport, Cell Nucleus , Cell Line , Centrifugation , Humans , Immunoprecipitation , Protein Binding , Two-Hybrid System Techniques
6.
Integr Cancer Ther ; 12(3): 248-56, 2013 May.
Article in English | MEDLINE | ID: mdl-23027830

ABSTRACT

Previous studies have shown that soybean fermentation products can act as cancer chemoprevention or therapeutic agents. In this study, the anticancer activities of a fermentation product of soybean, black bean, and green bean mixture (BN999) were investigated. We found that BN999 inhibited the growth of human breast cancer AU565 cells and prostate adenocarcinoma PC-3 cells but not that of normal human cells. BN999 induced apoptosis in various human cancer cells but not in normal human cells. BN999 treatment of AU565 cancer cells resulted in activation of calpain and caspase-8, -9, and -3, suggesting that BN999 induces apoptosis via receptor-, mitochondria-, and endoplasmic reticulum-mediated pathways. Finally, we showed that BN999 inhibited the growth of mouse CT-26 colon cancer xenografts in syngenic BALB/c mice without causing obvious side effects. Together, these data suggest that BN999 has potential to be used as a cancer chemoprevention or therapeutic agent.


Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Fabaceae/chemistry , Glycine max/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Animals , Caspases/metabolism , Cell Line, Tumor , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/metabolism , Fabaceae/metabolism , Fermentation , Humans , Male , Mice , Mice, Inbred BALB C , Mitochondria/drug effects , Mitochondria/metabolism , Glycine max/metabolism
7.
PLoS One ; 7(9): e45563, 2012.
Article in English | MEDLINE | ID: mdl-23029100

ABSTRACT

In this study, we demonstrated that 10'(Z), 13'(E)-heptadecadienylhydroquinone (HQ17-2), isolated from the lacquer tree, could decrease swarming motility and hemolysin activity but increase polymyxin B (PB) susceptibilityof Proteus mirabilis which is intrinsically highly-resistant to PB. The increased PB susceptibility induced by HQ17-2 was also observed in clinical isolates and biofilm-grown cells. HQ17-2 could inhibit swarming in the wild-type and rppA mutant but not in the rcsB mutant, indicating that HQ17-2 inhibits swarming through the RcsB-dependent pathway, a two-component signaling pathway negatively regulating swarming and virulence factor expression. The inhibition of hemolysin activity by HQ17-2 is also mediated through the RcsB-dependent pathway, because HQ17-2 could not inhibit hemolysin activity in the rcsB mutant. Moreover, the finding that HQ17-2 inhibits the expression of flhDC gene in the wild-type and rcsB-complemented strain but not in the rcsB mutant supports the notion. By contrast, HQ17-2 could increase PB susceptibility in the wild-type and rcsB mutant but not in the rppA mutant, indicating that HQ17-2 increases PB susceptibility through the RppA-dependent pathway, a signaling pathway positively regulating PB resistance. In addition, HQ17-2 could inhibit the promoter activities of rppA and pmrI, a gene positively regulated by RppA and involved in PB resistance, in the wild-type but not in the rppA mutant. The inhibition of rppA and pmrI expression caused lipopolysaccharide purified from HQ17-2-treated cells to have higher affinity for PB. Altogether, this study uncovers new biological effects of HQ17-2 and provides evidence for the potential of HQ17-2 in clinical applications.


Subject(s)
Anti-Bacterial Agents/pharmacology , Hydroquinones/pharmacology , Polymyxin B/pharmacology , Proteus mirabilis/drug effects , Proteus mirabilis/genetics , Virulence Factors , Acyltransferases/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Drug Synergism , Gene Expression Regulation, Bacterial , Hemolysin Proteins/metabolism , Microbial Sensitivity Tests , Mutation , Promoter Regions, Genetic/drug effects , Proteus mirabilis/metabolism , Signal Transduction , Virulence Factors/genetics , Virulence Factors/metabolism
8.
Cancer Lett ; 324(1): 48-57, 2012 Nov 01.
Article in English | MEDLINE | ID: mdl-22546288

ABSTRACT

HER2-overexpressing cancer cells are resistant to cisplatin (CDDP) and doxorubicin (DXR). Here we report that SV40 T/t-common polypeptide could specifically sensitize HER2-overexpressing cancer cells to CDDP and DXR and specifically enhance CDDP- or DXR-induced apoptosis in these cells. This activity of T/t-common may be attributed to its ability to inhibit Bcl-2 and Bcl-XL and to suppress ERK activity in CDDP- or DXR-treated HER2-overexpressing cancer cells. T/t-common could enhance the antitumor activity of DXR on HER2-overexpressing ovarian tumor in NOD/SCID mice, suggesting that combination therapy using T/t-common and chemotherapeutic agents may provide a new approach for treating HER2-overexpressing cancers.


Subject(s)
Antigens, Polyomavirus Transforming/metabolism , Antineoplastic Agents/pharmacology , Cisplatin/pharmacology , Doxorubicin/pharmacology , Receptor, ErbB-2/metabolism , Animals , Antigens, Polyomavirus Transforming/genetics , Apoptosis/drug effects , Female , Gene Expression Regulation, Neoplastic , Humans , Mice , Mice, SCID , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/genetics , Ovarian Neoplasms/metabolism , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Receptor, ErbB-2/genetics , Tumor Cells, Cultured , Xenograft Model Antitumor Assays , bcl-X Protein/genetics , bcl-X Protein/metabolism
9.
J Nat Prod ; 75(4): 689-93, 2012 Apr 27.
Article in English | MEDLINE | ID: mdl-22429052

ABSTRACT

Investigation of the leaves and twigs of Callicarpa longissima resulted in the isolation of four new compounds (1-4), callilongisins A-D, and five known compounds, ursolic acid, 3-oxoanticopalic acid, (E)-6ß-hydroxylabda-8(17),13-dien-15-oic acid, 5-hydroxy-3,6,7,4'-tetramethoxyflavone, and artemetin. Compounds 1-3 are 3,4-seco-abietane-type diterpenoids, and compound 4 is an analogue of a labdenoic-type diterpene. The structure of compound 1 was confirmed by X-ray crystallographic analysis. Cytotoxicity against a human prostate cancer cell line (PC3) and anti-inflammatory activities of the isolated compounds were evaluated.


Subject(s)
Anti-Inflammatory Agents/isolation & purification , Anti-Inflammatory Agents/pharmacology , Antineoplastic Agents, Phytogenic/isolation & purification , Antineoplastic Agents, Phytogenic/pharmacology , Callicarpa/chemistry , Diterpenes/isolation & purification , Diterpenes/pharmacology , Anti-Inflammatory Agents/chemistry , Antineoplastic Agents, Phytogenic/chemistry , Crystallography, X-Ray , Diterpenes/chemistry , Drug Screening Assays, Antitumor , Humans , Male , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Leaves/chemistry
10.
BMC Cancer ; 10: 175, 2010 Apr 30.
Article in English | MEDLINE | ID: mdl-20429953

ABSTRACT

BACKGROUND: Advanced cancer is a multifactorial disease that demands treatments targeting multiple cellular pathways. Chinese herbal cocktail which contains various phytochemicals may target multiple dys-regulated pathways in cancer cells and thus may provide an alternative/complementary way to treat cancers. Previously we reported that the Chinese herbal cocktail Tien-Hsien Liguid (THL) can specifically induce apoptosis in various cancer cells and have immuno-modulating activity. In this study, we further evaluated the anti-metastatic, anti-angiogenic and anti-tumor activities of THL with a series of in vitro and in vivo experiments. METHODS: The migration and invasion of cancer cells and endothelial cells was determined by Boyden chamber transwell assays. The effect of THL on pulmonary metastasis was done by injecting CT-26 colon cancer cells intravenously to syngenic mice. The in vitro and in vivo microvessel formation was determined by the tube formation assay and the Matrigel plug assay, respectively. The in vivo anti-tumor effect of THL was determined by a human MDA-MB-231 breast cancer xenograft model. The expression of metalloproteinase (MMP)-2, MMP-9, and urokinase plasminogen activator (uPA) was measured by gelatin zymography. The expression of HIF-1alpha and the phosphorylation of ERK1/2 were determined by Western blot. RESULTS: THL inhibited the migration and invasion ability of various cancer cells in vitro, decreased the secretion of MMP-2, MMP-9, and uPA and the activity of ERK1/2 in cancer cells, and suppressed pulmonary metastasis of CT-26 cancer cells in syngenic mice. Moreover, THL inhibited the migration, invasion, and tube formation of endothelial cells in vitro, decreased the secretion of MMP-2 and uPA in endothelial cells, and suppressed neovascularization in Matrigel plugs in mice. Besides its inhibitory effect on endothelial cells, THL inhibited hypoxia-induced HIF-1alpha and vascular endothelial growth factor-A expression in cancer cells. Finally, our results show that THL inhibited the growth of human MDA-MB-231 breast cancer xenografts in NOD-SCID mice. This suppression of tumor growth was associated with decreased microvessel formation and increased apoptosis caused by THL. CONCLUSION: Our data demonstrate that THL had broad-spectra anti-cancer activities and merits further evaluation for its use in cancer therapy.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Breast Neoplasms/drug therapy , Cell Movement/drug effects , Colonic Neoplasms/drug therapy , Drugs, Chinese Herbal/pharmacology , Lung Neoplasms/prevention & control , Neovascularization, Pathologic/prevention & control , Animals , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Line, Tumor , Colonic Neoplasms/blood supply , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Dose-Response Relationship, Drug , Endothelial Cells/drug effects , Endothelial Cells/pathology , Female , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Lung Neoplasms/secondary , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Mice , Mice, Inbred BALB C , Mice, Inbred NOD , Mice, SCID , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Neoplasm Invasiveness , Time Factors , Tumor Burden , Urokinase-Type Plasminogen Activator/metabolism , Vascular Endothelial Growth Factor A/metabolism , Xenograft Model Antitumor Assays
11.
Antimicrob Agents Chemother ; 54(5): 2000-9, 2010 May.
Article in English | MEDLINE | ID: mdl-20160049

ABSTRACT

Proteus mirabilis is known to be highly resistant to the action of polymyxin B (PB). However, the mechanism underlying PB resistance is not clear. In this study, we used Tn5 transposon mutagenesis to identify genes that may affect PB resistance in P. mirabilis. Two genes, ugd and galU, which may encode UDP-glucose dehydrogenase (Ugd) and UDP-glucose pyrophosphorylase (GalU), respectively, were identified. Knockout mutants of ugd and galU were found to be extremely sensitive to PB, presumably because of alterations in lipopolysaccharide (LPS) structure and cell surface architecture in these mutants. These mutants were defective in swarming, expressed lower levels of virulence factor hemolysin, and had lower cell invasion ability. Complementation of the ugd or galU mutant with the full-length ugd or galU gene, respectively, led to the restoration of wild-type phenotypic traits. Interestingly, we found that the expression of Ugd and GalU was induced by PB through RppA, a putative response regulator of the bacterial two-component system that we identified previously. Mutation in either ugd or galU led to activation of RpoE, an extracytoplasmic function sigma factor that has been shown to be activated by protein misfolding and alterations in cell surface structure in other bacteria. Activation of RpoE or RpoE overexpression was found to cause inhibition of FlhDC and hemolysin expression. To our knowledge, this is the first report describing the roles and regulation of Ugd and GalU in P. mirabilis.


Subject(s)
Drug Resistance, Bacterial/genetics , Fluoroquinolones/pharmacology , Polymyxin B/pharmacology , Proteus mirabilis/genetics , UTP-Glucose-1-Phosphate Uridylyltransferase/genetics , Uridine Diphosphate Glucose Dehydrogenase/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Cell Wall/drug effects , Flagellin/genetics , Gene Expression Regulation, Bacterial/physiology , Gene Knockout Techniques , Hemolysin Proteins/genetics , Molecular Sequence Data , Movement/physiology , Mutagenesis , Phenotype , Proteus mirabilis/drug effects , Proteus mirabilis/pathogenicity , UTP-Glucose-1-Phosphate Uridylyltransferase/metabolism , Uridine Diphosphate Glucose Dehydrogenase/metabolism , Virulence
12.
Antimicrob Agents Chemother ; 54(4): 1564-71, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20123999

ABSTRACT

Proteus mirabilis is naturally resistant to polymyxin B (PB). To investigate the underlying mechanisms, Tn5 mutagenesis was performed, and a mutant exhibiting increased PB susceptibility was isolated. The mutant was found to have Tn5 inserted into the PpmrI (Proteus pmrI) gene, a gene which may encode a UDP-glucuronic acid decarboxylase. In other bacteria, pmrI belongs to the seven-gene pmrF operon, which is involved in lipopolysaccharide (LPS) modification. While the PpmrI knockout mutant had a wild-type LPS profile and produced amounts of LPS similar to those produced by the wild type, LPS of the knockout mutant had higher PB-binding activity than that of the wild type. PB could induce alterations of LPS in the wild type but not in the PpmrI knockout mutant. Moreover, the PpmrI knockout mutant exhibited decreased abilities in biofilm formation and urothelial cell invasion. Complementation of the PpmrI mutant with the full-length PpmrI gene led to restoration of the wild-type phenotypic traits. Previously we identified RppA, a response regulator of the bacterial two-component system, as a regulator of PB susceptibility and virulence factor expression in P. mirabilis. Here we showed that RppA could mediate the induction of PpmrI expression by PB. An electrophoretic mobility shift assay further demonstrated that RppA could bind directly to the putative PpmrI promoter. Together, these results provide a new insight into the regulatory mechanism underlying PB resistance and virulence expression in P. mirabilis.


Subject(s)
Genes, Bacterial , Polymyxin B/pharmacology , Proteus mirabilis/drug effects , Proteus mirabilis/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Base Sequence , Biofilms/drug effects , Biofilms/growth & development , Carboxy-Lyases/genetics , Cell Line , DNA Primers/genetics , DNA, Bacterial/genetics , Drug Resistance, Bacterial/genetics , Epithelial Cells/microbiology , Gene Expression Regulation, Bacterial , Genetic Complementation Test , Humans , Lipopolysaccharides/genetics , Lipopolysaccharides/metabolism , Molecular Sequence Data , Mutagenesis, Insertional , Operon , Phenotype , Promoter Regions, Genetic , Proteus mirabilis/pathogenicity , Proteus mirabilis/physiology , Urothelium/microbiology
13.
Carcinogenesis ; 30(2): 366-75, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19126642

ABSTRACT

The Epstein-Barr virus nuclear antigen 2 (EBNA2) plays a key role in transformation of B-lymphocytes mediated by Epstein-Barr virus (EBV) and can induce tumor formation in transgenic mice. However, the precise mechanism underlying EBNA2-mediated tumorigenesis remains elusive. Here, we report that EBNA2 can compromise mitotic spindle checkpoint (MSC) induced by the spindle inhibitor nocodazole and cause chromosomal instability (CIN) in HEp-2, U2-OS and BJAB cells. When EBNA2-expressing cells were treated with nocodazole, they exited mitosis prematurely and initiated another round of DNA synthesis. Nucleolocalization of EBNA2 was essential for EBNA2 to compromise MSC and to cause CIN. The metaphase chromosome spread data indicated that the EBNA2-expressing U2-OS cells showed a more heterogenous chromosome number distribution than the vector-transfected and parental cells. The median chromosome number for EBNA2-expressing, vector-transfected and parental U2-OS cells is 75, 65 and 64, respectively. EBNA2 was shown to be able to downregulate mitotic arrest deficient 2 (MAD2) approximately 2- to 3-fold and upregulate polo-like kinase 1 (PLK1) approximately 2-fold. The dysregulation of MAD2 and PLK1 may lead to activation of anaphase promoting complex/cyclosome and premature degradation of securin. Indeed, we found that when MSC was induced by nocodazole, securin was prematurely degraded in EBNA2-expressing cells. Finally, we show that EBNA2 could induce micronuclei and multinuclei formation in HEp-2 and U2-OS cells. Together, these studies reveal a new function of EBNA2 in cell-cycle regulation and may shed light on the role of EBNA2 in EBV-mediated tumorigenesis.


Subject(s)
Cell Transformation, Neoplastic , Chromosomal Instability/physiology , Epstein-Barr Virus Nuclear Antigens/physiology , Mitosis , Animals , Calcium-Binding Proteins/metabolism , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Down-Regulation , Humans , Mad2 Proteins , Micronuclei, Chromosome-Defective , Nocodazole/pharmacology , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Repressor Proteins/metabolism , Polo-Like Kinase 1
14.
Infect Immun ; 76(5): 2051-62, 2008 May.
Article in English | MEDLINE | ID: mdl-18316383

ABSTRACT

Proteus mirabilis, a human pathogen that frequently causes urinary tract infections, is intrinsically highly resistant to cationic antimicrobial peptides, such as polymyxin B (PB). To explore the mechanisms underlying P. mirabilis resistance to PB, a mutant which displayed increased (> 160-fold) sensitivity to PB was identified by transposon mutagenesis. This mutant was found to have Tn5 inserted into a novel gene, rppA. Sequence analysis indicated that rppA may encode a response regulator of the two-component system and is located upstream of the rppB gene, which may encode a membrane sensor kinase. An rppA knockout mutant of P. mirabilis had an altered lipopolysaccharide (LPS) profile. The LPS purified from the rppA knockout mutant could bind more PB than the LPS purified from the wild type. These properties of the rppA knockout mutant may contribute to its PB-sensitive phenotype. The rppA knockout mutant exhibited greater swarming motility and cytotoxic activity and expressed higher levels of flagellin and hemolysin than the wild type, suggesting that RppA negatively regulates swarming, hemolysin expression, and cytotoxic activity in P. mirabilis. PB could modulate LPS synthesis and modification, swarming, hemolysin expression, and cytotoxic activity in P. mirabilis through an RppA-dependent pathway, suggesting that PB could serve as a signal to regulate RppA activity. Finally, we demonstrated that the expression of rppA was up-regulated by a low concentration of PB and down-regulated by a high concentration of Mg2+. Together, these data highlight the essential role of RppA in regulating PB susceptibility and virulence functions in P. mirabilis.


Subject(s)
Bacterial Proteins/physiology , Drug Resistance, Bacterial , Gene Expression Regulation, Bacterial , Locomotion , Polymyxin B/pharmacology , Proteus mirabilis/physiology , Virulence Factors/biosynthesis , Anti-Bacterial Agents/pharmacology , Cell Line , DNA Transposable Elements , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Flagellin/biosynthesis , Gene Deletion , Hemolysin Proteins/biosynthesis , Humans , Lipopolysaccharides/analysis , Lipopolysaccharides/isolation & purification , Lipopolysaccharides/metabolism , Molecular Sequence Data , Mutagenesis, Insertional , Polymyxin B/metabolism , Proteus mirabilis/chemistry , Proteus mirabilis/drug effects , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Urothelium/microbiology
15.
J Med Microbiol ; 55(Pt 10): 1313-1321, 2006 Oct.
Article in English | MEDLINE | ID: mdl-17005777

ABSTRACT

Resveratrol (3,5,4-trihydroxy-trans-stilbene) is a phytoalexin compound with anti-inflammatory and antioxidant activities. The effect of resveratrol on swarming and virulence factor expression of Proteus mirabilis, an important pathogen infecting the urinary tract, was determined on swarming agar plates with and without the compound. Bacteria harvested at different times were assayed for cell length and the production of flagella, haemolysin and urease. Resveratrol inhibited P. mirabilis swarming and virulence factor expression in a dose-dependent manner. Resveratrol significantly inhibited swarming at 15 microg ml(-1), and completely inhibited swarming at 60 microg ml(-1). Inhibition of swarming and virulence factor expression was mediated through RsbA, a His-containing phosphotransmitter of the bacterial two-component signalling system possibly involved in quorum sensing. Complementation of an rsbA-defective mutant with the rsbA gene restored its responsiveness to resveratrol. The compound also inhibited the ability of P. mirabilis to invade human urothelial cells. These findings suggest that resveratrol has potential to be developed as an antimicrobial agent against P. mirabilis infection.


Subject(s)
Proteus mirabilis/drug effects , Stilbenes/pharmacology , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/physiology , Cell Line, Tumor , Dose-Response Relationship, Drug , Genetic Complementation Test , Humans , Movement/drug effects , Mutation , Proteus mirabilis/metabolism , Proteus mirabilis/physiology , Resveratrol , Virulence Factors/antagonists & inhibitors , Virulence Factors/metabolism
16.
Cancer Res ; 66(11): 5847-57, 2006 Jun 01.
Article in English | MEDLINE | ID: mdl-16740724

ABSTRACT

Previously, we reported that SV40 T/t-common polypeptide, which contains the NH(2)-terminal common domain of SV40 large T and small t antigens, can repress HER2/neu (also known as erbB-2) expression and consequently suppress the tumorigenic potential of the HER2/neu-overexpressing ovarian carcinoma cells. Here we report that T/t-common could specifically induce apoptosis in HER2/neu-overexpressing human cancer cell lines but not in nontransformed cell lines and HER2/neu low-expressing human cancer cell lines. The ability of T/t-common to induce apoptosis in HER2/neu-overexpressing cancer cells was derived from its ability to inhibit HER2/neu because reexpression of a large amount of HER2/neu could block apoptosis induced by T/t-common. T/t-common expression in HER2/neu-overexpressing SK-OV-3 cancer cells led to down-regulation of Bcl-2 and Bcl-X(L), and overexpression of Bcl-2 could inhibit the ability of T/t-common to induce apoptosis in these cells. Therefore, the apoptosis-inducing activity of T/t-common is related to its ability to inhibit Bcl-2 expression in HER2/neu-overexpressing cancer cells. Consistent with the apoptosis-inducing activity of T/t-common, we found that T/t-common could specifically inhibit the soft-agarose colony-forming ability of the HER2/neu-overexpressing human cancer cell lines but not that of the HER2/neu low-expressing human cancer cell lines. Finally, we showed that T/t-common could specifically sensitize HER2/neu-overexpressing human cancer cell lines, but not HER2/neu low-expressing human cancer cell lines, to chemotherapeutic agent etoposide. Together, these data suggest that T/t-common alone or in combination with chemotherapy may provide a new approach for treatment of cancers that overexpress HER2/neu.


Subject(s)
Antigens, Polyomavirus Transforming/physiology , Apoptosis/physiology , Neoplasms/metabolism , Neoplasms/pathology , Receptor, ErbB-2/biosynthesis , Antigens, Polyomavirus Transforming/biosynthesis , Antigens, Polyomavirus Transforming/genetics , Apoptosis Regulatory Proteins/metabolism , Cell Line, Tumor , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/metabolism , Genetic Therapy/methods , HeLa Cells , Humans , Neoplasms/genetics , Protein Structure, Tertiary , Receptor, ErbB-2/antagonists & inhibitors , Transfection
17.
Am J Chin Med ; 33(4): 559-71, 2005.
Article in English | MEDLINE | ID: mdl-16173530

ABSTRACT

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. Our previous study found that THL can modulate the antigen-stimulated proliferative response of peripheral blood mononuclear cells and T-cells isolated from RAU patients. In this study, we further tested whether THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. To achieve this goal, T-cells isolated from 19 RAU patients were incubated with phytohemagglutinin (PHA), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. The levels of interleukin (IL)-2, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), IL-6, or IL-10 in the supernatants of T-cell cultures were measured by cytokine enzyme-linked immunosorbent assay (ELISA) kits. We found that THL significantly increased the PHA- or TT-stimulated TNF-alpha, IL-6, and IL-10 production by T-cells isolated from RAU patients. However, THL could also significantly decrease the TT-stimulated IL-2 production, the GtfD-stimulated IL-2, TNF-alpha, IL-6 and IL-10 production, and the S. mutans-stimulated IFN-gamma, TNF-alpha, and IL-10 production by T-cells isolated from RAU patients. These results indicate that THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. Because RAU is probably a Thl-mediated disease with elevated levels of IL-2, IFN-gamma, TNF-alpha and IL-6 in either the patient's sera or oral lesions and these increased levels of cytokines can be reduced by THL, we suggest that THL may be a potential immunoceutical agent for treatment of RAU.


Subject(s)
Cytokines/metabolism , Drugs, Chinese Herbal/pharmacology , Stomatitis, Aphthous/drug therapy , Stomatitis, Aphthous/immunology , T-Lymphocytes/drug effects , Adult , Antigens, Bacterial/immunology , Female , Glucosyltransferases/immunology , Humans , In Vitro Techniques , Male , Middle Aged , Phytohemagglutinins/immunology , Recurrence , Streptococcus mutans/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Tetanus Toxin/immunology
18.
J Altern Complement Med ; 11(2): 245-56, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15865490

ABSTRACT

OBJECTIVE: Tien-Hsien liquid (THL) is a commercially available Chinese herbal mixture that has been used as an anticancer dietary supplement for more than 10 years. We recently showed that THL has strong immunomodulatory effects on peripheral blood mononuclear cells (PBMC) and T cells. To investigate the antitumor activity of THL further, we sought to test whether THL could induce apoptosis in various human cancer cell lines based on the fact that THL contains several components with tumor killing functions. DESIGN: The growth inhibitory effect of THL on human cervical carcinoma C-33A cells, human lung carcinoma H1299 cells, and human PBMC was assessed by counting viable cells using the trypan blue dye exclusion method. The apoptosis-inducing activity of THL in H1299 cells was assessed by analyzing the cells with four assays: (1) Hoechst 33258 nuclear DNA staining; (2) the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) assay; (3) the nucleosomal DNA fragment ladder assay; and (4) the sub-G1 cell analysis. The activities of caspase-8, -9, and -3 in H1299 cells treated with or without THL were also measured to elucidate the possible mechanism underlying THL apoptosis-inducing effect. Finally, the apoptotic effect of THL on fifteen human cancer cell lines and normal human cells were analyzed by the TUNEL assay. RESULTS: THL could induce apoptosis in all human cancer cell lines tested but not in normal human cells. THL treatment of H1299 cancer cells resulted in activation of caspase-8, -9, and -3 and the inhibitors of these caspases could partially block THL-induced apoptosis. CONCLUSIONS: THL has been used by numerous patients with cancer for many years with no known adverse effect. Our present study showing that THL had a broad-range tumor killing function has provided a molecular basis underlying THL therapeutic activity. Furthermore, because THL had apoptotic effects only on cancer cells but not on normal cells, this selectivity suggests that THL could be a potential cancer therapeutic agent.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Carcinoma/drug therapy , Drugs, Chinese Herbal/pharmacology , Dose-Response Relationship, Drug , Flow Cytometry , Humans , Immunoassay , In Situ Nick-End Labeling , Tumor Cells, Cultured/drug effects
19.
Infect Immun ; 72(12): 6836-45, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15557604

ABSTRACT

After sensing external signals, Proteus mirabilis undergoes a multicellular behavior called swarming which is coordinately regulated with the expression of virulence factors. Here we report that exogenously added fatty acids could act as signals to regulate swarming in P. mirabilis. Specifically, while oleic acid enhanced swarming, some saturated fatty acids, such as lauric acid, myristic acid, palmitic acid, and stearic acid, inhibited swarming. We also found that expression of hemolysin, which has been shown to be coordinately regulated with swarming, was also inhibited by the above saturated fatty acids. Previously we identified a gene, rsbA, which may encode a histidine-containing phosphotransmitter of the bacterial two-component signaling system and act as a repressor of swarming and virulence factor expression in P. mirabilis. We found that while myristic acid, lauric acid, and palmitic acid exerted their inhibitory effect on swarming and hemolysin expression through an RsbA-dependent pathway, the inhibition by stearic acid was mediated through an RsbA-independent pathway. Biofilm formation and extracellular polysaccharide (EPS) production play an important role in P. mirabilis infection. We found that RsbA may act as a positive regulator of biofilm formation and EPS production. Myristic acid was found to slightly stimulate biofilm formation and EPS production, and this stimulation was mediated through an RsbA-dependent pathway. Together, these data suggest that fatty acids may act as environmental cues to regulate swarming and virulence in P. mirabilis and that RsbA may play an important role in this process.


Subject(s)
Bacterial Proteins/physiology , Fatty Acids/pharmacology , Proteus mirabilis/drug effects , Biofilms , Gene Expression Regulation, Bacterial , Polysaccharides, Bacterial/biosynthesis , Proteus mirabilis/pathogenicity , Proteus mirabilis/physiology , Virulence Factors/analysis
20.
Am J Chin Med ; 32(2): 221-34, 2004.
Article in English | MEDLINE | ID: mdl-15315260

ABSTRACT

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. In our institution, an immunomodulating agent, levamisole, is used to treat RAU with satisfactory therapeutic effect. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. To test whether THL has immunomodulating effects on antigen-stimulated proliferation response (PR) of peripheral blood mononuclear cells (PBMC) and T-cells isolated from RAU patients and to test whether THL is a potential drug for treating RAU, PBMC or T-cells isolated from RAU patients were incubated with lipopolysaccharides (LPS) from Escherica coli, phytohemagglutinin (PHA), staphylococcal enterotoxin B (SEB), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. We found that THL significantly increased the LPS-stimulated PR of PBMC from active RAU patients, the GtfD-stimulated PR of PBMC and of T-cells from inactive RAU patients, and the S. mutans-stimulated PR of PBMC from inactive RAU patients. However, THL could also significantly reduce the SEB-stimulated PR of PBMC and of T-cells from active RAU patients and S. mutans-stimulated PR of T-cells from active RAU patients. These results suggest that THL can modulate the antigen-stimulated PR of PBMC and T-cells from RAU patients. Therefore, it may be a potential immunoceutical agent for treatment of RAU.


Subject(s)
Drugs, Chinese Herbal/pharmacology , Leukocytes, Mononuclear/drug effects , Stomatitis, Aphthous/drug therapy , Stomatitis, Aphthous/immunology , T-Lymphocytes/drug effects , Cell Culture Techniques , Cell Division , Humans , Lipopolysaccharides/pharmacology
SELECTION OF CITATIONS
SEARCH DETAIL
...