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PubMed2003

Vitamin C inhibits FAS-induced apoptosis in monocytes and U937 cells.

The FAS receptor-FAS ligand system is a key apoptotic pathway for cells of the immune system. Ligation of the FAS-receptor (CD95) induces apoptosis by activation of pro-caspase-8 followed by downstream events, including an increase in reactive oxygen species (ROS) and the release of proapoptotic factors from the mitochondria, leading to caspase-3 activation. We investigated the role of vitamin C in FAS-mediated apoptosis and found that intracellular accumulation of pharmacologic concentrations of vitamin C inhibited FAS-induced apoptosis in the monocytic U937 cell line and in fresh human monocytes. Cells were loaded with vitamin C by exposure to dehydroascorbic acid (DHA), thereby circumventing in vitro artifacts associated with the poor transport and pro-oxidant effects of ascorbic acid (AA). Vitamin C inhibition of FAS-mediated apoptosis was associated with reduced activity of caspase-3, -8, and -10, as well as diminished levels of ROS and preservation of mitochondrial membrane integrity. Mechanistic studies indicated that the major effect of vitamin C was inhibition of the activation of caspase-8 with no effect on it enzymatic activity. An independent action of high intracellular concentrations of vitamin C on mitochondrial membrane stabilization was also detected. These studies illuminate the nature of redox-dependent signaling in FAS-induced apoptosis of human monocytes and suggest that vitamin C can modulate the immune system by inhibiting FAS-induced monocyte death.

Apoptosis↗

PubMed2006

KLF2 provokes a gene expression pattern that establishes functional quiescent differentiation of the endothelium.

The flow-responsive transcription factor KLF2 is acquiring a leading role in the regulation of endothelial cell gene expression. A genome-wide microarray expression profiling is described employing lentivirus-mediated, 7-day overexpression of human KLF2 at levels observed under prolonged flow. KLF2 is not involved in lineage typing, as 42 endothelial-specific markers were unaffected. Rather, KLF2 generates a gene transcription profile (> 1000 genes) affecting key functional pathways such as cell migration, vasomotor function, inflammation, and hemostasis and induces a morphology change typical for shear exposure including stress fiber formation. Protein levels for thrombomodulin, endothelial nitric oxide synthase, and plasminogen activator inhibitor type-1 are altered to atheroprotective levels, even in the presence of the inflammatory cytokine TNF-alpha. KLF2 attenuates cell migration by affecting multiple genes including VEGFR2 and the potent antimigratory SEMA3F. The distribution of Weibel-Palade bodies in cultured cell populations is normalized at the single-cell level without interfering with their regulated, RalA-dependent release. In contrast, thrombin-induced release of Weibel-Palade bodies is significantly attenuated, consistent with the proposed role of VWF release at low-shear stress regions of the vasculature in atherosclerosis. These results establish that KLF2 acts as a central transcriptional switch point between the quiescent and activated states of the adult endothelial cell.

Cell Differentiation↗

PubMed2026

Study of NSD2 using a dTAG system reveals its molecular mechanism and oncogenic implications in t(4;14) multiple myeloma.

The histone H3 lysine 36 dimethylation (H3K36me2) methyltransferase NSD2 is deleted in Wolf-Hirschhorn syndrome and is aberrantly expressed in 10% to 15% of patients with multiple myeloma (MM) because of a t(4;14) translocation. Although NSD2 is thought to be a primary driver in MM, the exact molecular mechanisms by which it regulates transcription remain unclear. We applied the degradation tag (dTAG) system to acutely degrade NSD2 and used this, in combination with time-resolved thiol-linked alkylation for the metabolic sequencing of RNA (SLAM-seq), to identify 307 transcriptional targets of NSD2. Reconstitution with either wild-type NSD2 or a catalytically inactive mutant (NSD2Y1179A) showed that NSD2's transcriptional effects are almost exclusively dependent on its SET domain activity. Mechanistically, H3K36me2 deposition by NSD2 antagonizes H3K27me3 levels, and treatment with 2 distinct Polycomb repressive complex 2 inhibitors demonstrated that approximately half of the NSD2 target genes are regulated in an H3K27me3-dependent manner. Cleavage under targets and tagmentation (CUT&Tag) analysis showed that upon NSD2 depletion, there was an increase in H3K27me3 that occurred at genome-wide intergenic regions rather than at the promoters or gene bodies of NSD2 target genes. These data suggest that NSD2, via H3K36me2, antagonizes H3K27me3 deposition likely at distal regulatory elements, including enhancers, creating a chromatin landscape favorable for target gene transcription. Importantly, NSD2 target genes were enriched for key oncogenic pathways, and 24 transcription factors (TFs) implicated in neurodevelopment and acute leukemia, consistent with its role in Wolf-Hirschhorn syndrome and MM. Eight of these TFs are known oncogenic drivers in acute leukemia or MM, highlighting a novel molecular mechanism for NSD2's role in t(4;14) MM.

Histone-Lysine N-Methyltransferase↗

PubMed2005

Inhaled tolafentrine reverses pulmonary vascular remodeling via inhibition of smooth muscle cell migration.

BACKGROUND: The aim of the study was to assess the chronic effects of combined phosphodiesterase 3/4 inhibitor tolafentrine, administered by inhalation, during monocrotaline-induced pulmonary arterial hypertension (PAH) in rats. METHODS: CD rats were given a single subcutaneous injection of monocrotaline to induce PAH. Four weeks after, rats were subjected to inhalation of tolafentrine or sham nebulization in an unrestrained, whole body aerosol exposure system. In these animals (i) the acute pulmonary vasodilatory efficacy of inhaled tolafentrine (ii) the anti-remodeling effect of long-term inhalation of tolafentrine (iii) the effects of tolafentrine on the expression profile of 96 genes encoding cell adhesion and extracellular matrix regulation were examined. In addition, the inhibitory effect of tolafentrine on ex vivo isolated pulmonary artery SMC cell migration was also investigated. RESULTS: Monocrotaline injection provoked severe PAH (right ventricular systolic pressure increased from 25.9 +/- 4.0 to 68.9 +/- 3.2 after 4 weeks and 74.9 +/- 5.1 mmHg after 6 weeks), cardiac output depression and right heart hypertrophy. The media thickness of the pulmonary arteries and the proportion of muscularization of small precapillary resistance vessels increased dramatically, and the migratory response of ex-vivo isolated pulmonary artery smooth muscle cells (PASMC) was increased. Micro-arrays and subsequent confirmation with real time PCR demonstrated upregulation of several extracellular matrix regulation and adhesion genes, such as matrixmetalloproteases (MMP) 2, 8, 9, 10, 11, 12, 20, Icam, Itgax, Plat and serpinb2. When chronically nebulized from day 28 to 42 (12 daily aerosol maneuvers), after full establishment of severe pulmonary hypertension, tolafentrine reversed about 60% of all hemodynamic abnormalities, right heart hypertrophy and monocrotaline-induced structural lung vascular changes, including the proportion of pulmonary artery muscularization. The upregulation of extracellular matrix regulation and adhesion genes was reduced by nearly 80% by inhalation of the tolafentrine. When assessed in vitro, tolafentrine blocked the enhanced PASMC migratory response. CONCLUSION: In conclusion, we demonstrate for the first time that inhalation of combined PDE3/4 inhibitor reverses pulmonary hypertension fully developed in response to monocrotaline in rats. This "reverse-remodeling" effect includes structural changes in the lung vascular wall and key molecular pathways of matrix regulation, concomitant with 60% normalization of hemodynamics.

Administration, Inhalation↗

PubMed2006

RhoA signaling modulates cyclin D1 expression in human lung fibroblasts; implications for idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic Pulmonary Fibrosis (IPF) is a debilitating disease characterized by exaggerated extracellular matrix deposition and aggressive lung structural remodeling. Disease pathogenesis is driven by fibroblastic foci formation, consequent on growth factor overexpression and myofibroblast proliferation. We have previously shown that both CTGF overexpression and myofibroblast formation in IPF cell lines are dependent on RhoA signaling. As RhoA-mediated regulation is also involved in cell cycle progression, we hypothesise that this pathway is key to lung fibroblast turnover through modulation of cyclin D1 kinetic expression. METHODS: Cyclin D1 expression was compared in primary IPF patient-derived fibroblasts and equivalent normal control cells. Quantitative real time PCR was employed to examine relative expression levels of cyclin D1 mRNA; protein expression was confirmed by western blotting. Effects of Rho signaling were investigated using transient transfection of constitutively active and dominant negative RhoA constructs as well as pharmacological inhibitors. Cellular proliferation of lung fibroblasts was determined by BrdU incorporation ELISA. To further explore RhoA regulation of cyclin D1 in lung fibroblasts and associated cell cycle progression, an established Rho inhibitor, Simvastatin, was incorporated in our studies. RESULTS: Cyclin D1 expression was upregulated in IPF compared to normal lung fibroblasts under exponential growth conditions (p < 0.05). Serum deprivation inhibited cyclin D1 expression, which was restored following treatment with fibrogenic growth factors (TGF-beta1 and CTGF). RhoA inhibition, using a dominant negative mutant and a pharmacological inhibitor (C3 exotoxin), suppressed levels of cyclin D1 mRNA and protein in IPF fibroblasts, with significant abrogation of cell turnover (p < 0.05). Furthermore, Simvastatin dose-dependently inhibited fibroblast cyclin D1 gene and protein expression, inducing G1 cell cycle arrest. Similar trends were observed in control experiments using normal lung fibroblasts, though exhibited responses were lower in magnitude. CONCLUSION: These findings report for the first time that cyclin D1 expression is deregulated in IPF through a RhoA dependent mechanism that influences lung fibroblast proliferation. This potentially unravels new molecular targets for future anti-IPF strategies; accordingly, Simvastatin inhibition of Rho-mediated cyclin D1 expression in IPF fibroblasts merits further exploitation.

ADP Ribose Transferases↗

PubMed2006

Permutation test for periodicity in short time series data.

BACKGROUND: Periodic processes, such as the circadian rhythm, are important factors modulating and coordinating transcription of genes governing key metabolic pathways. Theoretically, even small fluctuations in the orchestration of circadian gene expression patterns among different tissues may result in functional asynchrony, at the organism level, and may contribute to a wide range of pathologic disorders. Identification of circadian expression pattern in time series data is important, but equally challenging. Microarray technology allows estimation of relative expression of thousands of genes at each time point. However, this estimation often lacks precision and microarray experiments are prohibitively expensive, limiting the number of data points in a time series expression profile. The data produced in these experiments carries a high degree of stochastic variation, obscuring the periodic pattern and a limited number of replicates, typically covering not more than two complete periods of oscillation. RESULTS: To address this issue, we have developed a simple, but effective, computational technique for the identification of a periodic pattern in relatively short time series, typical for microarray studies of circadian expression. This test is based on a random permutation of time points in order to estimate non-randomness of a periodogram. The Permutated time, or Pt-test, is able to detect oscillations within a given period in expression profiles dominated by a high degree of stochastic fluctuations or oscillations of different irrelevant frequencies. We have conducted a comprehensive study of circadian expression on a large data set produced at PBRC, representing three different peripheral murine tissues. We have also re-analyzed a number of similar time series data sets produced and published independently by other research groups over the past few years. CONCLUSION: The Permutated time test (Pt-test) is demonstrated to be effective for detection of periodicity in short time series typical for high-density microarray experiments. The software is a set of C++ programs available from the authors on the open source basis.

Algorithms↗

PubMed2004

Microarray gene expression profiling and analysis in renal cell carcinoma.

BACKGROUND: Renal cell carcinoma (RCC) is the most common cancer in adult kidney. The accuracy of current diagnosis and prognosis of the disease and the effectiveness of the treatment for the disease are limited by the poor understanding of the disease at the molecular level. To better understand the genetics and biology of RCC, we profiled the expression of 7,129 genes in both clear cell RCC tissue and cell lines using oligonucleotide arrays. METHODS: Total RNAs isolated from renal cell tumors, adjacent normal tissue and metastatic RCC cell lines were hybridized to affymatrix HuFL oligonucleotide arrays. Genes were categorized into different functional groups based on the description of the Gene Ontology Consortium and analyzed based on the gene expression levels. Gene expression profiles of the tissue and cell line samples were visualized and classified by singular value decomposition. Reverse transcription polymerase chain reaction was performed to confirm the expression alterations of selected genes in RCC. RESULTS: Selected genes were annotated based on biological processes and clustered into functional groups. The expression levels of genes in each group were also analyzed. Seventy-four commonly differentially expressed genes with more than five-fold changes in RCC tissues were identified. The expression alterations of selected genes from these seventy-four genes were further verified using reverse transcription polymerase chain reaction (RT-PCR). Detailed comparison of gene expression patterns in RCC tissue and RCC cell lines shows significant differences between the two types of samples, but many important expression patterns were preserved. CONCLUSIONS: This is one of the initial studies that examine the functional ontology of a large number of genes in RCC. Extensive annotation, clustering and analysis of a large number of genes based on the gene functional ontology revealed many interesting gene expression patterns in RCC. Most notably, genes involved in cell adhesion were dominantly up-regulated whereas genes involved in transport were dominantly down-regulated. This study reveals significant gene expression alterations in key biological pathways and provides potential insights into understanding the molecular mechanism of renal cell carcinogenesis.

Adenocarcinoma, Clear Cell↗

PubMed2026

Differentiating hemorrhagic shock and organophosphate poisoning through integrated skin microbiome-metabolome signatures.

Accurate determination of cause of death and estimation of postmortem interval (PMI) are critical yet challenging tasks in forensic science, particularly in cases with rapid demise and absence of obvious morphological abnormalities. We employed an integrative multi-omics approach to characterize postmortem microbial succession and metabolic alterations on facial skin in mouse models of hemorrhagic shock (HS) and organophosphorus poisoning (OP) across three decomposition stages: bloating (2 days), active decay (8 days), and advanced decay (16 days). Metagenomic profiling revealed significantly reduced α-diversity in HS compared with OP throughout all stages (p < 0.001), accompanied by stage-dependent compositional shifts, including early enrichment of Firmicutes in HS and Proteobacteria in OP. A total of 237 differential taxa were identified, with Providencia and Morganella predominating in OP, whereas Staphylococcus and Corynebacterium dominated bloating stage of HS. Untargeted metabolomics uncovered distinct cause-of-death-linked metabolites, notably elevated 2'-deoxycytidine-5'-diphosphate in early OP and persistent cholic acid/cholate accumulation in HS at later PMI. Functional analysis highlighted histidine and phosphate/phosphonate metabolism as key discriminatory pathways, exhibiting stage-specific oscillations and strong correlations with characteristic taxa. These findings demonstrate that skin-based metagenomic-metabolomic integration provides robust, mechanistically informed biomarkers for both PMI estimation and cause-of-death differentiation, offering a minimally invasive and temporally dynamic tool for forensic investigations.

Animals↗

PubMed2025

Modulation of the tumor microenvironment by the ubiquitin-proteasome system in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide, with the tumor microenvironment (TME) playing a pivotal role in its progression and therapeutic resistance. The ubiquitin-proteasome system (UPS), a central regulator of intracellular protein degradation, is increasingly recognized for its involvement in cancer pathogenesis, though its specific role in modulating the CRC TME remains to be fully elucidated. This review aims to systematically summarize current evidence on how the UPS influences the immunosuppressive network within the CRC TME and to evaluate its potential as a therapeutic target. METHODS: We conducted a comprehensive literature search in PubMed, Web of Science, and Scopus databases for original research articles and reviews published between January 2010 and August 2025, using keywords including "ubiquitin-proteasome system," "colorectal cancer," "tumor microenvironment,""immune escape,"and "targeted therapy." Studies were selected based on their relevance to UPS-mediated regulatory mechanisms in CRC TME remodeling, immune cell function, and treatment response. RESULTS: Our analysis of preclinical and clinical evidence reveals that the UPS critically regulates immune evasion in CRC through multiple mechanisms: (1) USP14 stabilizes indoleamine 2,3-dioxygenase 1 (IDO1), enhancing tryptophan catabolism and kynurenine accumulation, which suppresses T-cell activity; (2) E3 ligases including SPOP, C-Cbl, KLHL22, and FBW7 modulate PD-L1/PD-1 protein stability via ubiquitination, thereby influencing immune checkpoint signaling; and (3) ZFP91 facilitates K63-linked ubiquitination of PP2Ac, impairing mTORC1-mediated glycolysis in T cells and reinforcing regulatory T-cell immunosuppression. Additionally, the UPS intersects with key oncogenic pathways such as Wnt/β-catenin, NF-κB, and p53, further shaping the immunosuppressive landscape of CRC. CONCLUSIONS: Targeting the UPS represents a promising strategy to reverse immunosuppression and overcome therapy resistance in CRC. The primary advantage of this approach lies in its ability to simultaneously disrupt multiple immunosuppressive pathways within the TME, offering a potential solution to the limitations of single-target therapies. Current approaches include proteasome inhibitors, E3 ligase modulators, and deubiquitinating enzyme inhibitors, with combination regimens-such as UPS inhibitors with immune checkpoint blockade-showing synergistic efficacy in preclinical models. Future efforts should focus on enhancing the selectivity of UPS-targeting agents, minimizing off-target effects, and integrating genomic profiling to guide personalized treatment. While current evidence strongly supports the therapeutic potential of UPS targeting, its establishment as a reliable alternative therapy in the clinic will depend on overcoming these challenges and validating efficacy in human trials. This review underscores the UPS as a central regulator of the CRC TME and provides a rational basis for novel therapeutic development.

Humans↗

PubMed2026

Targeting super-enhancer-driven SKIL transcription by CDK7 inhibitor THZ1 to suppress gastric cancer progression.

BACKGROUND: Gastric cancer (GC) is a lethal malignancy characterized by high incidence, mortality, and limited treatment options. Transcriptional addiction is a key cancer hallmark that drives tumor pathogenesis, making its inhibition a promising therapeutic strategy for GC. The study aims to investigate the roles and mechanisms of super-enhancer (SE)-driven oncogenic transcriptional addiction in GC progression and to identify novel targetable vulnerabilities. METHODS: We utilized cellular and animal models to assess the effects of THZ1 treatment and CDK7 knockdown on GC progression. RNA sequencing was employed to elucidate the potential molecular mechanism of THZ1 treatment. ChIP-seq was performed to establish SE landscape in GC. Integrative analysis of transcriptomic and SE profiling was used to identify THZ1-targeted oncogenic genes. Rescue experiments were conducted to confirm that THZ1 treatment suppresses GC malignant progression by targeting SE-driven SKIL transcription. RESULTS: GC cells exhibited pronounced sensitivity to THZ1 compared to normal gastric mucosa cells, and the treatment potently suppressed tumor growth and migration in both cellular and animal models. CDK7 was significantly upregulated in GC tissues, and its knockdown inhibited malignant progression in vitro and in vivo, whereas its overexpression accelerated tumor progression. Mechanistically, SE-driven oncogenic transcriptional amplification underlies GC cell susceptibility to THZ1, supported by the identification of novel oncogenic genes such as SKIL. SKIL, a key Hippo pathway regulator, was highly expressed in GC cells, and its elevated expression predicted poor patient prognosis. SKIL silencing attenuated malignant phenotypes, while its overexpression diminished THZ1’s suppression of GC cell proliferation and migration. CONCLUSION: Our findings demonstrate that THZ1 inhibits GC progression by disrupting SE-driven oncogenic transcription, thereby offering CDK7 inhibition as a promising therapeutic intervention for GC.

Stomach Neoplasms↗

PubMed2026

Deciphering the genetic background of an industrial 2-ketogluconic acid-producing strain Pseudomonas plecoglossicida JUIM01 using whole-genome sequencing.

2-Ketogluconic acid (2KGA) is an important precursor for the food antioxidant erythorbic acid, currently produced via microbial fermentation using Pseudomonas species. To facilitate the genetic improvement of production strains, the complete genome of an industrial 2KGA producer P. plecoglossicida JUIM01 was sequenced and analyzed. The genome consists of a 5.13-Mb circular chromosome with a GC content of 63.58%, encoding 4,517 predicted proteins. Comprehensive functional annotation identified a putative global regulatory network comprising 75 core regulators, which were classified into six functionally cooperative modules, potentially governing the strain's metabolism and environmental adaptability. We further delineated the genetic determinants hypothetically linked to efficient 2KGA synthesis, including glucose metabolism, fatty acid metabolism, and the oxidative phosphorylation system. These outputs could provide the genomic resource for elucidating high productivity and robustness, and rationally engineering the high-performance chassis cells toward robust 2KGA production.

P. plecoglossicida↗

PubMed2006

Chemokines, chemokine receptors, and cancer metastasis.

It is clear from large clinical studies that selected chemokine receptors are often up-regulated in a large number of common human cancers, including those of the breast, lung, prostate, colon, and melanoma. Chemokine receptors and their corresponding chemokine ligands have been demonstrated to play a number of nonredundant roles in cancer metastasis to vital organs as well as regional lymph nodes, the most frequent site of cancer metastasis. Chemokine receptors may potentially facilitate tumor dissemination at several key steps of metastasis, including adherence of tumor cells to endothelium, extravasation from blood vessels, metastatic colonization, angiogenesis, proliferation, and protection from the host response via activation of key survival pathways such as phosphatidylinositol-3 kinase and Akt. It is interesting that many of these roles are reminiscent of their functions in leukocyte and stem cell trafficking. Lastly, we discuss therapeutic applications for chemokine receptor antagonists in cancer therapy.

Animals↗

PubMed2004

Identification of key beta cell gene signaling pathways involved in type 1 diabetes.

In type 1 diabetes, beta cells die through a process of immune-mediated apoptosis. To better understand this process, it has been accepted practice to study beta cell or islet apoptosis in vitro in response to a range of immune stimuli, such as interferon gamma, interleukin-1, nitric oxide or free radicals. In particular, much use has been made of immortalized beta cell lines for such studies, although it is not clear to what extent the behavior of these cell lines might mimic the behavior of normal beta cells in vivo, or freshly isolated beta cells ex vivo. To address this question we compared the gene expression of freshly isolated NOD islets in the presence or absence of insulitis, with previously published data examining either islet or beta cell gene or protein expression in a range of different species and contexts. There was a high correlation between beta cell genes found be to be expressed by mouse and rat islets, by either gene expression or proteomic analysis. There was also a surprisingly high correlation between beta cell genes found be to be expressed by islets exposed to insulitis in vivo and islets stimulated with IFN-gamma and IL-1beta in vitro, suggesting that these two cytokines as produced by the islet infiltrate are important for priming beta cells in vivo. There was a much lower correlation when gene expression was compared between fresh beta cells and beta cell lines, consistent with the view that beta cell lines are very poorly representative of real beta cells. Hence, any results obtained using beta cell lines should be interpreted with great caution when extrapolating to the behavior of real beta cells.

Animals↗

PubMed2006

Role of cellular compartmentation in the metabolic response to stress: mechanistic insights from computational models.

The mechanisms controlling ATP generation in the transition from normal resting conditions to either high work states or ischemia are poorly understood. ATP generation depends upon compartmentation between the mitochondria and cytosol of metabolic pathways and key energy transfer species that cannot be easily assessed experimentally. We developed a multicompartment mathematical model of cardiac metabolism to simulate the metabolic responses to ischemia and increased workload. The model is based on mass balances, transport, and metabolic processes in cardiac tissue, and has three distinct compartments (blood, cytosol, and mitochondria). In addition to distinguishing between cytosol and mitochondria, the model includes a cytosolic subcompartment for glycolytic metabolic channeling. The model simulations predict the rapid activation of glycogenolysis and lactate production at the onset of ischemia, and support the concept of localization of glycolysis to a cytosolic subcompartment. In addition, simulations show that mitochondrial NADH/NAD(+) is primarily determined by oxygen consumption during ischemia, while cytosolic NADH/NAD(+) and lactate production are largely a function of glycolytic flux during the initial phase, and is controlled by mitochondrial NADH/NAD(+) and the malate-aspartate shuttle during the steady state. Finally, the model predicts that metabolic activation with an abrupt increase in workload requires parallel activation of ATP hydrolysis, glycolysis, mitochondrial dehydrogenases, the electron transport chain, and ADP phosphorylation. Taken together, these studies demonstrate the importance of metabolic compartmentation in the regulation of cardiac energetics in response to acute stress, and they highlight the usefulness of computational models in this line of investigation.

Animals↗

PubMed2005

Tumor-specific expression of vascular endothelial growth factor receptor 2 but not vascular endothelial growth factor or human epidermal growth factor receptor 2 is associated with impaired response to adjuvant tamoxifen in premenopausal breast cancer.

PURPOSE: Vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) are often coexpressed in breast cancer, and potentially affect cellular pathways and key proteins such as the estrogen receptor (ER) targeted by endocrine treatment. We therefore explored the association between adjuvant tamoxifen treatment in breast cancer and expression of VEGF-A and VEGFR2, as well as human epidermal growth factor receptor 2 (HER2), which represents a candidate gene product involved in tamoxifen resistance. PATIENTS AND METHODS: Immunohistochemical expression of tumor-specific VEGF-A, VEGFR2, and HER2 was evaluated in tumor specimens from premenopausal breast cancer patients randomly assigned to 2 years of tamoxifen or no treatment (n = 564), with 14 years of follow-up. Hormone receptor status was determined in 96% of the tumors. RESULTS: VEGF-A, VEGFR2, and HER2 were assessable in 460, 472, and 428 of the tumors, respectively. In patients with ER-positive and VEGFR2-low tumors, adjuvant tamoxifen significantly increased recurrence-free survival (RFS; [HR] hazard ratio for RFS, 0.53; P = .001). In contrast, tamoxifen treatment had no effect in patients with VEGFR2-high tumors (HR for RFS, 2.44; P = .2). When multivariate interaction analyses were used, this difference in treatment efficacy relative to VEGFR2 expression status was statistically significant for both ER-positive (P = .04) plus ER-positive and progesterone receptor-positive tumors. We found no significant difference in tamoxifen treatment effects in relation to VEGF-A or HER2 status. CONCLUSION: Tumor-specific expression of VEGFR2 was associated with an impaired tamoxifen effect in hormone receptor-positive premenopausal breast cancer. Tamoxifen in combination with VEGFR2 inhibitors might be a novel treatment approach for VEGFR2-expressing breast cancer, and such a treatment might restore the tamoxifen response.

Adult↗

PubMed2006

Combination therapy with the advanced glycation end product cross-link breaker, alagebrium, and angiotensin converting enzyme inhibitors in diabetes: synergy or redundancy?

Blockade of advanced glycation end product (AGE) accumulation with alagebrium with concomitant angiotensin converting enzyme inhibition was tested for effects on renal function and on other postulated mediators of diabetic renal disease including the renin-angiotensin system, AGEs, mitochondrial and cytosolic oxidative stress, and intracellular signaling molecules. Sprague Dawley rats were rendered diabetic with streptozocin and followed consecutively for 32 wk with nondiabetic controls. Groups were treated with ramipril (1 mg/kg.d; wk 0-32); alagebrium (10 mg/kg.d; wk 16-32); or a combination of both. Although individual treatments had significant effects on albuminuria, no further improvements were seen with combination therapy. Changes in urinary vascular endothelial growth factor excretion mirrored those seen in albuminuria. Diabetes was associated with suppression of circulating angiotensin II in the context of increased circulating and renal levels of the AGE, carboxymethyllysine. All treatments attenuated circulating but not renal carboxymethyllysine levels. The renal gene expression of AGE receptor 1 and soluble receptor for advanced glycation end products were markedly reduced by diabetes and normalized with alagebrium. Diabetes induced renal mitochondrial oxidative stress, which was reduced with alagebrium. In the cytosol, both therapies were equally effective in reducing reactive oxygen species production. Increases in membranous protein kinase C activity in diabetes were attenuated by all treatments, whereas diabetes-associated increases in nuclear factor-kappaB p65 translocation remained unaltered by any therapy. It is evident that renin-angiotensin system blockade and AGE inhibition have specific effects. However, many of their downstream effects appear to be similar, suggesting that their renoprotective benefits may ultimately involve common pathways and key points of convergence, which could be important targets for new therapies in diabetic nephropathy.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Hormone-induced receptor gene splicing: enhanced expression of the growth factor type I follicle-stimulating hormone receptor motif in the developing mouse ovary as a new paradigm in growth regulation.

The acquisition of FSH receptor(s) during follicular growth and their coupling to signaling pathways are key events in follicular development and dominance. However, little is known about the precise nature of the FSH receptor(s) involved in the growth-promoting phases of hormone action. To investigate the hormonal regulation of a newly discovered, alternatively spliced, growth factor type 1 receptor (designated FSH-R3) for the hormone, we examined expression in the adult mouse and the effect of PMSG treatment in the immature mouse ovary. Using RT-PCR and primers based on the established sheep ovarian transcript, a part of the FSH-R3 message was amplified only in wild-type (+/+), but not in the FSH-R knockout (-/-), mouse ovary. Semiquantitative RT-PCR using 3'-end primers specific for FSH-R1 (G(s)-coupled) and FSH-R3 indicated expression levels of the latter to be higher when follicular growth was induced by PMSG. Using FSH-R3-specific peptide IgG, FSH-R3 protein was detected by Western blotting in extracts of adult mouse ovary and was localized in granulosa cell membrane of mature follicles. In the immature mouse, levels of FSH-R3 protein that increased after PMSG administration in a time-dependent manner were also localized only on granulosa cell membranes of large follicles. The results reveal for the first time the expression of a different growth-promoting receptor for FSH in the developing and cycling mouse ovary. These observations introduce a new paradigm in the control of ovarian function.

Alternative Splicing↗

PubMed2005

A Pbx1-dependent genetic and transcriptional network regulates spleen ontogeny.

The genetic control of cell fate specification, morphogenesis and expansion of the spleen, a crucial lymphoid organ, is poorly understood. Recent studies of mutant mice implicate various transcription factors in spleen development, but the hierarchical relationships between these factors have not been explored. In this report, we establish a genetic network that regulates spleen ontogeny, by analyzing asplenic mice mutant for the transcription factors Pbx1, Hox11 (Tlx1), Nkx3.2 (Bapx1) and Pod1 (capsulin, Tcf21). We show that Hox11 and Nkx2.5, among the earliest known markers for splenic progenitor cells, are absent in the splenic anlage of Pbx1 homozygous mutant (-/-) embryos, implicating the TALE homeoprotein Pbx1 in splenic cell specification. Pbx1 and Hox11 genetically interact in spleen formation and loss of either is associated with a similar reduction of progenitor cell proliferation and failed expansion of the splenic anlage. Chromatin immunoprecipitation assays show that Pbx1 binds to the Hox11 promoter in spleen mesenchymal cells, which co-express Pbx1 and Hox11. Furthermore, Hox11 binds its own promoter in vivo and acts synergistically with TALE proteins to activate transcription, supporting its role in an auto-regulatory circuit. These studies establish a Pbx1-Hox11-dependent genetic and transcriptional pathway in spleen ontogeny. Additionally, we demonstrate that while Nkx3.2 and Pod1 control spleen development via separate pathways, Pbx1 genetically regulates key players in both pathways, and thus emerges as a central hierarchical co-regulator in spleen genesis.

Animals↗