Biomedical subjects

Liping Zhang

Publications and source records attributed to Liping Zhang.

At least 19 recordsLinked to original sources

PubMed2025

Identification of a prognostic signature consisting of three macrophage-related genes for glioblastoma based on bulk and single-cell transcriptomes analyses.

BACKGROUND: Tumor-associated macrophages have been implicated in the progression and treatment resistance of glioblastoma (GBM). This study aimed to identify macrophage-related genes associated with prognosis and therapeutic response in GBM. MATERIALS AND METHODS: Bulk RNA-seq data from 533 patients with GBM were downloaded from the Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases. Bioinformatic tools were used to detect the co-expression gene modules associated with the infiltration of immune cells, identify a prognostic macrophage-related gene signature, and explore their association with sensitivity to chemotherapeutic drugs and immune checkpoint blockade. Single-cell RNA-seq data and multiplexed immunofluorescence were used to validate ISG20 expression (a member of the identified gene signature) in macrophages. RESULTS: We detected gene modules associated with macrophages and identified a signature consisting of three macrophage-related genes (ISG20, PARP12 and IFIT5) in the discovery set (TCGA-GBM, n = 159), and validated its prognostic value in the validation set (CGGA-GBM, n = 374). This gene signature demonstrated favorable accuracy in predicting prognosis and resistance of immuno- and chemo-therapy. The co-expression of ISG20 and PD-1 in macrophages was verified by single-cell RNA-seq data and multiplex immunofluorescence. CONCLUSIONS: This study presents a macrophage-related gene signature to predict prognosis and therapeutic response in GBM. ISG20, PARP12 and IFIT5 are interferon-stimulated genes, and further investigations may provide new insights into the interplay between macrophages and interferon signaling in GBM.

Humans↗

PubMed2006

The combination of green tea and tamoxifen is effective against breast cancer.

Epidemiologic data have suggested that green tea may prevent breast cancer. Studies in our laboratory have provided evidence that green tea extract inhibits breast cancer growth by a direct anti-proliferative effect on the tumor cells, as well as by indirect suppressive effects on the tumor-associated endothelial cells. In this study, we asked whether concurrent administration of green tea may add to the anti-tumor effects of standard breast cancer therapy. We observed that green tea increased the inhibitory effect of tamoxifen on the proliferation of the ER (estrogen receptor)-positive MCF-7, ZR75, T47D human breast cancer cells in vitro. This combination regimen was also more potent than either agent alone at increasing cell apoptosis. In animal experiments, mice treated with both green tea and tamoxifen had the smallest MCF-7 xenograft tumor size, and the highest levels of apoptosis in tumor tissue, as compared with either agent administered alone. Moreover, the suppression of angiogenesis in vivo correlated with larger areas of necrosis and lower tumor blood vessel density in treated xenografts. Green tea decreased levels of ER-alpha in tumors both in vitro and in vivo. We also observed that green tea blocked ER-dependent transcription, as well as estradiol-induced phosphorylation and nuclear localization of mitogen-activated protein kinase. To our knowledge, this study is the first to show the interaction of green tea with the ER pathway, as well as provide mechanistic evidence that the combination of green tea and tamoxifen is more potent than either agent alone in suppressing breast cancer growth. These results may lead to future improvements in breast cancer treatment and prevention.

Animals↗

PubMed2006

Model-based drug development: the road to quantitative pharmacology.

High development costs and low success rates in bringing new medicines to the market demand more efficient and effective approaches. Identified by the FDA as a valuable prognostic tool for fulfilling such a demand, model-based drug development is a mathematical and statistical approach that constructs, validates, and utilizes disease models, drug exposure-response models, and pharmacometric models to facilitate drug development. Quantitative pharmacology is a discipline that learns and confirms the key characteristics of new molecular entities in a quantitative manner, with goal of providing explicit, reproducible, and predictive evidence for optimizing drug development plans and enabling critical decision making. Model-based drug development serves as an integral part of quantitative pharmacology. This work reviews the general concept, basic elements, and evolving role of model-based drug development in quantitative pharmacology. Two case studies are presented to illustrate how the model-based drug development approach can facilitate knowledge management and decision making during drug development. The case studies also highlight the organizational learning that comes through implementation of quantitative pharmacology as a discipline. Finally, the prospects of quantitative pharmacology as an emerging discipline are discussed. Advances in this discipline will require continued collaboration between academia, industry and regulatory agencies.

Adult↗

PubMed2006

Reaction progress of chromophore biogenesis in green fluorescent protein.

The mature form of green fluorescent protein (GFP) is generated by a spontaneous self-modification process that is essentially irreversible. A key step in chromophore biosynthesis involves slow air oxidation of an intermediate species, in which the backbone atoms of residues 65-67 have condensed to form a five-membered heterocycle. We have investigated the kinetics of hydrogen peroxide evolution during in vitro GFP maturation and found that the H2O2 coproduct is generated prior to the acquisition of green fluorescence at a stoichiometry of 1:1 (peroxide/chromophore). The experimental progress curves were computer-fitted to a three-step mechanism, in which the first step proceeds with a time constant of 1.5 (+/-1.1) min and includes protein folding and peptide cyclization. Kinetic data obtained by HPLC analysis support a rapid cyclization reaction that can be reversed upon acid denaturation. The second step proceeds with a time constant of 34.0 (+/-1.5) min and entails rate-limiting protein oxidation, as supported by a mass loss of 2 Da observed for tryptic peptides derived from species that accumulate during the reaction. The final step in GFP maturation proceeds with a time constant of 10.6 (+/-1.2) min, suggesting that this step may contribute to overall rate retardation. We propose that under highly aerobic conditions, the dominant reaction path follows a cyclization-oxidation-dehydration mechanism, in which dehydration of the heterocycle is facilitated by slow proton abstraction from the Tyr66 beta-carbon. In combination, the results presented here suggest a role for molecular oxygen in trapping the cyclized form of GFP.

Amino Acid Sequence↗

PubMed2006

[Primary grafting research of tissue engineered oral mucosa lamina propria on skin full thickness wounds].

OBJECTIVE: To study the allograft effect of two kinds of tissue engineered oral mucosa lamina propria on skin full-thickness wounds. METHODS: The cultured Wistar rat oral mucosa fibroblasts (OMF) were incorporated into collagen or chitosan-collagen to construct the tissue engineered oral mucosa lamina propria, and then the OMFs were labeled with BrdU. The full-thickness round skin defects were made with a round knife (diameter, 0.8 cm) on the backs of 36 Wistar rats (21-25 weeks old), which were divided into 2 experimental groups: the fibroblast-populated collagen lattices (FPCL) group (grafted by FPCLs) and the fibroblast-populated chitosan collagen lattices (FPCCL) group (grafted by FPCCLs), and the control group (only covered with gauges). All the wounds were observed by the naked eyes or the light microscope, and were measured 4, 7, 14, and 21 days postoperatively. RESULTS: There were no infection during the wound healing period. At 7 days after the grafting, the wounds in the 3 groups were covered by scab and/or gauze; at 14 days, the gauze and scab on the wounds in the three groups were all replaced by the new epidermis naturally except one scab each in the FPCCL group and the control groups, which was replaced at 17 days. All the centers of the new epidermis were measurable as the pink red points. At 21 days, all the new skins were smooth without hairs, and their color was similar to the normal one. At 4, 7, and 14 days, there was an indication that the wound diameters became significantly smaller in the three groups; but after the 14th day, there was no significant indication of this kind. At 7 days, the wound diameter in the FPCL group was significantly smaller than that in the FPCCL group and the control group (P < 0.01). Under the light microscope, at 4 days postoperatively, the decayed tissue on the surfaces of the recipient wounds in the FPCL group and the FPCCL group was separated from the lower granular tissue in which there were many inflammatory cells, fibroblasts, and new vessels. There was a similar phenomenon in the control group. Each skin wound in the three groups was only partly keratinocytes at 7 days postoperatively. The recipient wounds were wholly keratinocytes with when rete ridges observed at 14 and 21 days, but in the control group the wounds were keratinocytes with no rete ridges. Fibers in the new dermis were thin. The OMFs with Brdu appeared in the granular tissue and new dermis at 4, 7, 14, and 21 days postoperatively, which could be illustrated by the immunohistochemical staining. The positive OMFs and the granular tissue joined in the repair of the skin defects without any allergic reaction during the period of the wound healing. CONCLUSION: The oral mucosa fibroblasts as the new seed cells can join in the repair of the skin defects effectively and feasible. The fibroblast-populated collagen lattices and the fibroblast-populated chitosan collagen lattices can repair skin defects effectively and feasible, too. And the quality of the new skins was better in the two experimental groups than in the control group.

Animals↗

PubMed2005

Angiotensin II stimulates transcription of insulin-like growth factor I receptor in vascular smooth muscle cells: role of nuclear factor-kappaB.

Increased expression of the IGF-I receptor (IGF-IR) is associated with proliferation and survival of vascular smooth muscle cells (VSMCs). In cultured VSMCs, we reported that angiotensin II (Ang II) increases transcription and expression of IGF-IR. Now, we show that mesenteric arteries of rats infused with Ang II develop thickening and increased IGF-IR expression. To determine how Ang II transcriptionally regulates IGF-IR expression in VSMCs, we generated 5'-end deletions of the IGF-IR promoter and measured Ang II-induced promoter-luciferase activity in VSMCs. Activities from these promoter sequences suggested that the Ang II-responsive region is located between -270 and -135 of the IGF-IR promoter. Using a DNase I foot printing analysis, we identified two putative nuclear factor-kappaB (NF-kappaB)-like sequences located in the same region of the IGF-IR promoter. When we mutated either of these NF-kappaB-like sites, Ang II-induced IGF-IR promoter activity decreased sharply. Electrophoretic mobility gel shift, anti-p50 of NF-kappaB supershift and chromatin immunoprecipitation assays demonstrated that both the p65 and p50 subunits of NF-kappaB will bind to this Ang II response element in the IGF-IR promoter. When we blocked the Ras/MAPK kinase 1 pathway or the inhibitory-kappaB kinase pathway, both Ang II-induced IGF-IR promoter activity and expression of IGF-IR protein significantly declined. Our results indicate that the mechanism by which Ang II stimulates IGF-IR expression in VSMCs involves NF-kappaB binding to NF-kappaB sites in the IGF-IR promoter, leading to expression of IGF-IR through both Ras/MAPK kinase 1-and inhibitory-kappaB kinase-dependent pathways. Because IGF-IR is a major factor associated with thickening of mesenteric vessels, our results provide potential therapeutic targets.

Angiotensin II↗

PubMed2005

Analyzing multi-response data using forcing functions.

INTRODUCTION: Two analytic strategies can be taken to the analysis of multi-response data: a multivariate output model can be fit to all the response components simultaneously (SIM), or each response component can be fit separately to a univariate output model, conditioning in some way on the non-modeled components, the so-called forcing function approach (FFA). Focusing on a special case of multi-response model corresponding to a (pharmacokinetic) physiological f low model (PFM), the aims of this study are to (i) provide an algorithm for applying FFA to multi-response data from a PFM; (ii) examine the performance of FFA vs. SIM under optimal conditions for both, and in the presence of model misspecification; (iii) make recommendations regarding the use of FFA for multi-response data analysis. METHODS: The basic PFM we use (variants of the basic model are used for simulation) has four homogenous compartments among which drug distributes. All are sampled arterial blood (A), non-eliminating tissue (N), eliminating tissue (E), and venous blood (V), which is also the drug dosing site. Parameters are blood f low rates to E and N, volumes of distribution of A, E, N, and V, elimination rate constant from E, and observation error variances. Observations from a generic individual under various study designs and parameter values are simulated. Using data-analytic models (DAM) both the same as, and different than the data simulation model (DSM), SIM fits the PFM to all data simultaneously; FFA first fits each type of response (one per tissue) separately, approximating the tissue's input by linearly interpolating the observed concentrations from the donor tissue(s), estimates the identifiable parameter combinations for the response type, and then solves the simultaneous equations linking these across tissues, to obtain the primary model parameters of interest. This simulation and analysis steps are repeated to generate reliable performance statistics. Performances are compared with respect to parameter estimation error (when DAM and DSM are identical), and interpolated prediction error (when DAM and DSM are/are-not identical). The ability of SIM and FFA to identify the correct analytic model is also examined by comparing their failure rates in rejecting the wrong DAM. RESULTS: The parameter estimation errors with FFA are generally about two times greater than those with SIM when the DAM is identical to the DSM. The prediction errors of FFA are about ten times greater than those of SIM when the DAM is identical to the DSM, and are about three times greater when the two are different. However, SIM fails to identify the correct model twice as often as FFA. CONCLUSIONS: Despite its greater convenience for model building, and its clear advantages for model identification, FFA's final parameter estimates cannot be trusted when the multi-response system being modeled involves feedback. The size of the ratio of the two FFA residuals (obtained from the response-specific fits and from predictions made with the final FFA parameters) can, however, be used to indicate when FFA's final estimates may be trustworthy.

Algorithms↗

PubMed2005

Dual pathways for nuclear factor kappaB activation by angiotensin II in vascular smooth muscle: phosphorylation of p65 by IkappaB kinase and ribosomal kinase.

Activation of nuclear factor (NF)-kappaB by angiotensin II (Ang II) plays an essential role in stimulating expression of vascular adhesion molecules, which are essential for vascular inflammation. We report that Ang II activates NF-kappaB by phosphorylating its p65 subunit via a pathway mediated partially by ribosomal S6 kinase (RSK). In investigating other pathway(s) that may be involved, we found that the ability of Ang II to activate NF-kappaB in mouse embryonic fibroblast is suppressed (approximately 70%) either by deletion of IkappaB Kinase (IKK) or by inhibiting or knocking down IKK in vascular smooth muscle cells using a dominant-negative IKK adenovirus or small interference RNA to IKKbeta. Thus, Ang II also stimulates NF-kappaB via IKK. In vitro, we found that Ang II stimulates IKK to phosphorylate myelin basic protein and the p65 subunit of NF-kappaB. The mechanism by which Ang II activates IKK is to increase phosphorylation of IKKbeta in its activation loop (Ser181) rather than IkappaB phosphorylation. Inhibiting both the RSK and IKK pathways completely blocks the Ang II-induced p65 phosphorylation and NF-kappaB activation. These 2 pathways are independent: inhibiting IKK does not block Ang II-induced phosphorylation of RSK, whereas inhibiting mitogen-activated protein kinase 1 does not affect phosphorylation of IKK. Finally, we found that Ang II can induce expression of vascular adhesion molecules by 2 pathways; both IKK and RSK lead to phosphorylation of the p65 subunit of NF-kappaB to increase vascular cell adhesion molecule-1 transcription. The 2 pathways are functionally important because inhibiting IKK and RSK in vascular smooth muscle cells blocks Ang II-induced expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 to limit vascular inflammation.

Angiotensin II↗

PubMed2005

Administration of glutamate into the spinal cord at extracellular concentrations reached post-injury causes functional impairments.

In vivo experiments addressing the role of released glutamate in damage caused by neurotrauma seldom administer glutamate itself because it usually produces relatively little damage when administered into central nervous system (CNS) tissue in vivo. However, because of recent observations that glutamate administered into the spinal cord at the levels attained following spinal cord injury (SCI) kills neurons and oligodendrocytes, we tested the effects of administering glutamate at those concentrations on locomotor function. The Basso-Beattie-Bresnahan (BBB) test and activity box measures demonstrated that those glutamate concentrations produce lasting functional impairments. Several parameters provided by the activity box provided sensitive measures of the degree of post-SCI impairment, demonstrating their substantial potential for evaluating outcomes of SCI. Results obtained also enhance evidence that glutamate toxicity contributes to secondary damage following SCI and suggest that damage to white matter is an important contributor to such damage.

Animals↗

PubMed2005

The novel gene EG-1 stimulates cellular proliferation.

We recently discovered a novel gene and named it endothelial-derived gene 1 (EG-1). Previously, we have shown that the expression of EG-1 is significantly elevated in the epithelial cells of breast cancer, colorectal cancer, and prostate cancer. Here, we report that EG-1 can stimulate cellular proliferation. Transfection experiments which overexpressed the full-length EG-1 gene in human embryonic kidney HEK-293 cells or human breast cancer cell lines resulted in significantly increased in vitro proliferation, in comparison with transfection with empty vectors. On the other hand, small interfering RNA cotransfection resulted in inhibition of proliferation. S.c. xenograft assays were carried out in a severe combined immunodeficient mouse model. We found that injection of high EG-1 expressing HEK-293 clones resulted in significantly larger tumors, in comparison with clones carrying the empty vectors. To further clarify the function of this gene, we investigated its interaction with Src and members of the mitogen-activated protein kinase (MAPK) family. Immunoprecipitation with anti-Src antibody, followed by immunoblotting with anti-EG-1 antibody, showed an association between these two molecules. Overexpression of EG-1 was correlated with activation of the following kinases: extracellular signal-regulated kinases 1 and 2, c-jun-NH2-kinase, and p38. These observations collectively support the hypothesis that the novel gene EG-1 is a positive stimulator of cellular proliferation, and may possibly be involved in signaling pathways involving Src and MAPK activation.

Amino Acid Sequence↗

PubMed2005

A new human gene hNTKL-BP1 interacts with hPirh2.

NTKL (N-terminal kinase-like protein) encodes an evolutionarily conserved kinase-like protein and is mapped around chromosomal breakpoints found in several carcinomas, suggesting that NTKL dysfunction may be involved in carcinogenesis. Recently, we identified a novel mouse gene, mNTKL-BP1 (NTKL-binding protein 1), encoding a protein interacting with NTKL. For further study, a new human gene, hNTKL-BP1, which is highly homologous with mNTKL-BP1, was used as bait in yeast two-hybrid system. hPirh2 (human p53-induced RING-H2 protein) was identified as hNTKL-BP1 interacting protein. The specific interaction of two proteins was confirmed by pull-down assay in vitro and co-immunoprecipitation in vivo. Moreover, an immunofluorescent staining assay showed that hNTKL-BP1 colocalizes with hPirh2 in SMMC 7721 cells. It will stimulate further investigation into whether hNTKL-BP1 is the substrate of hPirh2 or interaction of hNTKL-BP1 with hPirh2 enhances or represses the ubiquitin-protein ligase activity of hPirh2.

Amino Acid Sequence↗

PubMed2005

A new cellular signaling mechanism for angiotensin II activation of NF-kappaB: An IkappaB-independent, RSK-mediated phosphorylation of p65.

OBJECTIVE: Angiotensin II (Ang II) promotes vascular inflammation and remodeling via activation of nuclear factor kappaB (NF-kappaB)-mediated transcription of proinflammatory genes such as interleukin-6 (IL-6). We examined the signaling mechanism whereby Ang II activates NF-kappaB in vascular smooth muscle cells (VSMCs). METHODS AND RESULTS: Ang II treatment did not increase phosphorylation of inhibitor of kappaBalpha (IkappaBalpha) or IkappaBbeta or decrease their levels. In contrast, mitogen-activated protein kinase kinase-1 (MEK1) inhibition (dominant-negative MEK1 adenovirus or inhibitor U0126) suppressed Ang II-induced NF-kappaB promoter activity, NF-kappaB DNA-binding activity, p65 phosphorylation, and led to 70% reduction in IL-6 transcription/production. The mechanism involved Ang II activation of Ras and MEK1. Signaling distal to MEK1 involved extracellular signal-regulated kinase (ERK) because inhibition of MEK1 suppressed the Ang II-induced activation of ribosomal S6 kinase (RSK), a substrate of ERK. Downregulation of RSK by small interfering RNA (SiRNA) in VSMCs was found to suppress Ang II-induced activation of NF-kappaB and p65 phosphorylation. Immunopurified RSK from Ang II-treated VSMCs phosphorylated recombinant glutathione S-transferase-p65 in vitro. CONCLUSIONS: We uncovered a nonclassical signaling pathway (Ras/MEK1/ERK/RSK) from Ang II to activation of NF-kappaB, a mechanism by which Ang II stimulates RSK-mediated phosphorylation of p65 to participate in vascular inflammation.

Angiotensin II↗

PubMed2005

Antiapoptotic effect of serum and glucocorticoid-inducible protein kinase is mediated by novel mechanism activating I{kappa}B kinase.

Serum and glucocorticoid inducible protein kinase (SGK) plays a crucial role in promoting cell survival, but the mechanisms for this response are not clear. We show that SGK is involved in the regulation of apoptosis in breast cancer cells by modulating the transcriptional activity of nuclear transcription factor kappaB (NF-kappaB). High levels of SGK expression were observed in human breast cancer samples. When SGK was reduced the apoptotic rate increased, and increased SGK activity prevents serum withdrawal-induced apoptosis. SGK-induced cell survival was abolished by a dominant-negative form of IkappaB kinase beta (IKKbeta, K44A) or a null mutation of IKKbeta in mouse embryonic fibroblast cells indicating involvement of the NF-kappaB pathway. Serum-induced SGK or increased expression of SGK activated NF-kappaB transcriptional activity, whereas small interference RNA to SGK blocked NF-kappaB activity. Coexpression of SGK and IKKbeta significantly increased the activation of NF-kappaB (versus expression of IKKbeta alone). Expression of dominant-negative IKKbeta K44A, IkappaBalpha AA, and kinase-dead SGK (127KM) blocked the ability of SGK to stimulate NF-kappaB activity, suggesting that IKKbeta is a target of SGK. We also show that SGK enhances the ability of IKKbeta to phosphorylate endogenous IkappaBalpha in cells or recombinant glutathione S-transferase-IkappaBalpha in vitro and increases IkappaBalpha degradation; SGK physically associates with and activates IKKbeta in MDA231 cells via phosphorylation of Ser(181) in IKKbeta. Taken together, we conclude that SGK acts as an oncogene in breast cancer cells through activation of the IKK-NF-kappaB pathway, thereby preventing apoptosis. Blocking SGK expression/activity represents a potential therapeutic approach for breast cancer treatment.

Active Transport, Cell Nucleus↗

PubMed2005

Seed germination and seedling emergence of three annuals growing on desert sand dunes in China.

BACKGROUND AND AIMS: Information on the initial growth characteristics of annuals found in Chinese deserts is very limited. The aim of this study was to investigate seed germination and interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in three annuals (Agriophyllum squarrosum, Bassia dasyphylla and Aristida adscensionis) commonly growing on sand dunes in these regions. METHODS: Effects of temperature, light and polyethylene glycol-6000 on seed germination were examined by irrigating seeds sown on filter paper in Petri dishes. Seedling emergence was examined for seeds sown on the surface of, or at different depths (5, 10, 20, 30, 40 and 50 mm) in, sand-filled pots, which were irrigated under different regimes. For seeds buried at a depth of 50 mm, seed viability was examined after irrigation of the pots. KEY RESULTS: Seeds of three species germinated at most temperatures recorded between spring and autumn in their native habitats. No seed dormancy was found in any species. For all three species, seedling emergence was most favoured when seeds were buried at a depth of 10 mm. When seeds sown on the sand surface were irrigated, seed germination was considerably suppressed due to water deficiency, but many seeds remained viable. For A. squarrosum and B. dasyphylla, many seeds that were deeply buried and irrigated remained ungerminated but viable, while for A. adscensionis deeply buried seeds germinated, but the seedlings did not emerge due to unfavourable seedling growth in deep sand. CONCLUSIONS: Precipitation is the most crucial factor in determining the seasonal emergence of seedlings of the three tested species in the field. The vertical distribution of seeds in sand determines the proportion of seeds that germinate after precipitation and acts to maintain seed banks over multiple years.

Amaranthaceae↗

PubMed2005

Foxa2 integrates the transcriptional response of the hepatocyte to fasting.

Survival during prolonged food deprivation depends on the activation of hepatic gluconeogenesis. Inappropriate regulation of this process is a hallmark of diabetes and other metabolic diseases. Activation of the genes encoding gluconeogenic enzymes is mediated by hormone-responsive transcription factors such as the cyclic AMP response element binding protein (CREB) and the glucocorticoid receptor (GR). Here we show using cell-type-specific gene ablation that the winged helix transcription factor Foxa2 is required for activation of the hepatic gluconeogenic program during fasting. Specifically, Foxa2 promotes gene activation both by cyclic AMP, the second messenger for glucagon, and glucocorticoids. Foxa2 mediates these effects by enabling recruitment of CREB and GR to their respective target sites in chromatin. We conclude that Foxa2 is required for execution of the hepatic gluconeogenic program by integrating the transcriptional response of the hepatocyte to hormonal stimulation.

Animals↗

PubMed2005

Transcriptional networks in the liver: hepatocyte nuclear factor 6 function is largely independent of Foxa2.

A complex network of hepatocyte nuclear transcription factors, including HNF6 and Foxa2, regulates the expression of liver-specific genes. The current model, based on in vitro studies, suggests that HNF6 and Foxa2 interact physically. This interaction is thought to synergistically stimulate Foxa2-dependent transcription through the recruitment of p300/CBP by HNF6 and to inhibit HNF6-mediated transcription due to the interference of Foxa2 with DNA binding by HNF6. To test this model in vivo, we utilized hepatocyte-specific gene ablation to study the binding of HNF6 to its targets in the absence of Foxa2. Chromatin immunoprecipitation using anti-HNF6 antibodies was performed on chromatin isolated from Foxa2(loxP/loxP) Alfp.Cre and control mouse livers, and HNF6 binding to its target, Glut2, was determined by quantitative PCR. In contrast to the current model, we found no significant difference in HNF6 occupancy at the Glut2 promoter between Foxa2-deficient and control livers. In order to evaluate the Foxa2/HNF6 interaction model on a global scale, we performed a location analysis using a microarray with 7,000 mouse promoter fragments. Again, we found no evidence that HNF6 binding to its targets in chromatin is reduced in the presence of Foxa2. We also examined the mRNA levels of HNF6 targets in the liver using a cDNA array and found that their expression was similar in Foxa2-deficient and control mice. Overall, our studies demonstrate that HNF6 binds to and regulates its target promoters in vivo in the presence and absence of Foxa2.

Animals↗

PubMed2005

Nipple fluid basic fibroblast growth factor in patients with breast cancer.

PURPOSE: It has been shown that early detection of breast cancer could save lives. Recently, there has been increasing interest in nipple fluid as a potential supplemental avenue for breast cancer diagnosis. EXPERIMENTAL DESIGN: In this study, we determined the levels of an angiogenic factor basic fibroblast growth factor (bFGF) in the nipple fluid of healthy subjects as well as patients with benign breast conditions, those at high risk for breast cancer, and patients with active breast cancer. ELISAs were used to measure bFGF. RESULTS: Nipple fluid bFGF levels were as follows (mean +/- SE): 158 +/- 17 pg/mL from benign breasts, 561 +/- 277 pg/mL from high-risk breasts, and 1,343 +/- 441 pg/mL from cancerous breasts. One-way ANOVA showed that the bFGF levels from cancerous breasts were significantly higher than those from benign and high-risk breasts (P = 0.0001 and P = 0.0193, respectively). After logarithmic transformation was applied to the data, high-risk breast bFGF levels were higher than those from benign breasts (P = 0.0028). With a cutoff level of 250 pg/mL, the sensitivity was 79.2%, specificity was 82.5%, and correct diagnosis was 66.4%. The area under the receiver operating characteristic curve was 0.86. CONCLUSIONS: We conclude that nipple fluid bFGF levels are progressively elevated in high-risk and cancerous breasts compared with benign breasts. The sensitivity and specificity of this test are promising compared with current breast cancer screening methods, and this test deserves further studies with larger clinical trials. Potential areas of usefulness include the detection of breast cancer risk or breast cancer, as well as the monitoring and/or prediction of the antiangiogenic effect of preventive therapies.

Adult↗

PubMed2005

Rabdosia rubescens inhibits breast cancer growth and angiogenesis.

Investigators have shown that PC-SPES is a potent herbal mixture which has often been used by prostate cancer patients. In this study, we examined the inhibitory effects of certain individual components of PC-SPES on the in vitro proliferation of the human breast cancer cells MDA-MB231 and the human umbilical vein endothelial cells (HUVEC). Our data showed that individual components of PC-SPES had varying suppressive effects on cellular proliferation, and that Rabdosia rubescens appeared to be the most potent agent in these assays. Apoptosis was up-regulated by Rabdosia rubescens, as seen in the caspase-9 and TUNEL assays. These effects may be mediated via both the MAPK (mitogen-activated protein kinase) and the Akt kinase pathways. In mouse experiments, the extract from Rabdosia rubescens suppressed breast cancer xenograft size and decreased the tumor vessel density. We conclude that Rabdosia rubescens may potentially be used to treat or prevent breast cancer, and that the extract from this herbal source deserves further studies.

Angiogenesis Inhibitors↗