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V Andrés

Publications and source records attributed to V Andrés.

At least 19 recordsLinked to original sources
PubMed2003

Inhibiting cyclin-dependent kinase/cyclin activity for the treatment of cancer and cardiovascular disease.

Excessive cell proliferation contributes to the pathobiology of human diseases with a high health and socio-economic impact, including cancer and vascular occlusive diseases (e. g., atherosclerosis, in-stent restenosis, transplant vasculopathy, and vessel bypass graft failure). Recent advances in the understanding of the molecular networks governing the hyperplastic growth of tumors and vascular obstructive neointimal lesions have provided new perspectives for preventive and therapeutic strategies against these disorders. Mammalian cell proliferation requires the activation of several cyclin-dependent protein kinases (CDKs). Postranslational activation of CDKs is a complex process that involves their association with regulatory subunits called cyclins. The activity of CDK/cyclin holoenzymes is negatively regulated through their interaction with members of the CDK family of inhibitory proteins (CKIs). Moreover, over fifty low molecular weight pharmacological CDK inhibitors that target the ATP-binding pocket of the catalytic site of CDKs have been identified. In this review, we will discuss the use of pharmacological and gene therapy strategies against CDK/cyclins in animal models and clinical trials of cancer and cardiovascular disease.

Animals↗
PubMed2001

Inhibition of the cyclin D1/E2F pathway by PCA-4230, a potent repressor of cellular proliferation.

1. Tight control of cellular growth is essential to ensure normal tissue patterning and prevent pathological responses. Excessive vascular smooth muscle cell (VSMC) proliferation is associated with the pathophysiology of atherosclerosis and restenosis post-angioplasty. Thus, drug targeting of pathological VSMC growth may be a suitable therapeutic intervention in vascular proliferative diseases. 2. In the present study, we investigated the mechanisms underlying VSMC growth arrest induced by the pharmacological agent PCA-4230. Addition of PCA-4230 to cultured VSMCs blocked the induction of cyclin D1 and cyclin A expression normally seen in serum-restimulated cells. Moreover, PCA-4230 inhibited cyclin-dependent kinase 2 (CDK2) activity and abrogated hyperphosphorylation of the retinoblastoma (Rb) gene product. Similarly, PCA-4230-dependent growth arrest of transformed cell lines correlated with reduced level of cyclin D1 protein and inhibition of CDK2 activity. Consistent with these findings, PCA-4230 repressed serum-inducible cyclin A promoter activity, and overexpression of either cyclin D1 or E2F1 efficiently circumvented this inhibitory effect. Importantly, adenovirus-mediated overexpression of E2F1 restored S-phase entry in PCA-4230-treated VSMCs, demonstrating that PCA-4230 represses cyclin A gene expression and VSMC growth via inhibition of the cyclin D1/E2F pathway. 3. Because of its ability to inhibit the growth of human VSMCs and transformed cell lines, future studies are warranted to assess whether PCA-4230 may be a suitable therapeutic intervention for the treatment of hyperproliferative disorders, including cardiovascular disease and cancer.

Animals↗
PubMed2001

Overexpression of p27(Kip1) by doxycycline-regulated adenoviral vectors inhibits endothelial cell proliferation and migration and impairs angiogenesis.

Formation of new blood vessels in the adult animal (i.e., angiogenesis) is an important event for tissue repair and for tumor growth and metastasis. Angiogenesis involves the migration and proliferation of endothelial cells. We have investigated the role of the growth suppressor p27(Kip1) (p27) on endothelial cell function in vitro and angiogenesis in vivo. We have generated Ad-TetON, a replication-deficient adenovirus that constitutively expresses the reverse tet-responsive transcriptional activator, and Ad-TRE-p27, which drives expression of p27 under the control of the tet response element. Western blot analysis demonstrated doxycycline-dependent overexpression of p27 in human umbilical vein endothelial cells (HUVECs) coinfected with Ad-TetON and Ad-TRE-p27, which resulted in a marked inhibition of DNA replication and cell migration in vitro. Inducible overexpression of p27 in cultured HUVECs inhibited the formation of tubelike structures and, when applied in a murine model of hind limb ischemia, reduced hind limb blood flow recovery and capillary density. These findings thus underscore a novel role of p27 in regulating endothelial cell migration in vitro and angiogenesis in vivo, suggesting a novel anti-angiogenic therapy based on inducible p27 overexpression.

Adenoviridae↗
PubMed2001

The growth suppressor p27(Kip1) protects against diet-induced atherosclerosis.

The molecular basis of atherosclerosis is associated with excessive proliferation of vascular cells. Previous studies have suggested an inverse correlation between the expression of the growth suppressor p27(Kip1) (p27) and cellular proliferation within human atherosclerotic tissue. However, no causal link between diminished p27 expression and atherogenesis has been established. We investigated the effect of p27 inactivation on diet-induced atherogenesis. We find that p27-deficient mice challenged with a high-fat diet for 1 month remain normocholesterolemic and have essentially no visible atheromas. However, when generated in an apolipoprotein E-null genetic background that leads to severe hypercholesterolemia in response to the atherogenic diet, deletion of p27 enhances arterial cell proliferation (approximately fourfold) and accelerates atherogenesis (approximately sixfold) compared with apolipoprotein E-deficient mice with an intact p27 gene. Analysis of apolipoprotein E-null mice bearing only one p27 allele inactivated reveals that a moderate decrease in p27 protein expression in the setting of hypercholesterolemia is sufficient to predispose to atherogenesis. Thus, our study establishes a molecular link between decreased p27 protein expression and atherogenesis in hypercholesterolemic animals.

Animals↗
PubMed2001

Role of Sp1 in the induction of p27 gene expression in vascular smooth muscle cells in vitro and after balloon angioplasty.

-The abnormal proliferation of vascular smooth muscle cells (VSMCs) plays an important role in atherosclerosis and restenosis. Although several studies have implicated the growth inhibitory protein p27(Kip1) (p27) in the control of myocyte growth and hypertrophy, little is known about the molecular mechanisms that regulate p27 expression in the cardiovascular system. In the present study, we demonstrate the interaction of the transcription factor Sp1 with 2 GC-rich sequences within the p27 promoter in cultured VSMCs. Importantly, point mutations that disrupted Sp1 binding markedly reduced p27 promoter activity, demonstrating that Sp1 is required for efficient p27 gene transcription in cultured VSMCs. Because p27 expression is upregulated after balloon angioplasty, we investigated Sp1 expression and activity in control and balloon-injured rat carotid arteries to assess the role of Sp1 as a physiological regulator of p27 expression. Although immunohistochemical analysis disclosed Sp1 protein expression in both control and balloon-injured arteries, a high level of Sp1 DNA-binding activity was found only in response to balloon angioplasty. Collectively, these results demonstrate that Sp1 is essential for maximum p27 promoter activity in VSMCs and suggest that posttranslational induction of Sp1 DNA-binding activity contributes to the induction of p27 expression and VSMC growth arrest at late time points after balloon angioplasty.

Angioplasty, Balloon↗
PubMed2000

Control of vascular smooth muscle cell growth by cyclin-dependent kinase inhibitory proteins and its implication in cardiovascular disease.

While quiescence is a defining characteristic of differentiated vascular smooth muscle cells (VSMCs) residing within the medial layer of elastic arteries in the adult organism, mature VSMCs can undergo phenotypic modulation and reenter the cell cycle in response to several physiological and pathological stimuli. Abnormal VSMC proliferation is thought to contribute to the pathogenesis of vascular occlusive lesions, including atherosclerosis, vessel renarrowing after successful angioplasty (restenosis), and graft atherosclerosis after coronary transplantation. Therefore, elucidating the molecular mechanisms limiting VSMC growth is currently the subject of active research. This review will focus on the role of cyclin-dependent kinase inhibitory proteins in the regulation of VSMC proliferation and its implication in intimal lesion formation during the pathogenesis of vascular proliferative diseases.

Arteriosclerosis↗
PubMed2000

Age-dependent increase in c-fos activity and cyclin A expression in vascular smooth muscle cells. A potential link between aging, smooth muscle cell proliferation and atherosclerosis.

OBJECTIVE: Aging can be defined as a progressive deterioration of biological functions after the organism has attained its maximal reproductive competence, which is usually associated with a decrease in proliferative ability in most cell types. However, in certain pathological situations such as atherosclerosis and restenosis, aging has been shown to be associated with a higher level of vascular smooth muscle cell (VSMC) proliferation and neointimal lesion formation after angioplasty. In the present study, we investigated potential mechanisms involved in the age-dependent increase in VSMC proliferation. METHODS AND RESULTS: Primary cultures of VSMCs were isolated from young (6-8-month-old) and old (4-5-year-old) New Zealand rabbits. Results from cell counting assays and FACS analysis were consistent with a shortening of the cell cycle in old VSMCs. Western blot analysis in serum stimulated cells showed a significant increase in the level of cyclin A and cyclin-dependent kinase 2 proteins in the old vs. young VSMCs. In marked contrast, expression of cyclin E in VSMCs was not influenced by aging. Transient transfection assays showed an age-dependent increase in transcription from the human cyclin A promoter. Parallel studies demonstrated that the expression of the AP1 transcription factor c-fos, which interacts with the cyclin A promoter and stimulates VSMC proliferation, was also increased in old VSMCs. Consistent with this notion, electrophoretic mobility shift assays demonstrated an increase in AP1 DNA-binding activity in old VSMCs. CONCLUSIONS: These studies suggest that age-associated increase in c-fos activity contributes to augmented cyclin A expression and VSMC proliferation in old animals. These mechanisms might contribute to the higher prevalence and severity of atherosclerosis in the elderly.

Aging↗
PubMed2000

Vascular smooth muscle cell proliferation in the pathogenesis of atherosclerotic cardiovascular diseases.

Atherosclerosis is the principal cause of myocardial infarction, stroke, and peripheral vascular disease, accounting for nearly half of all mortality in developed countries. For example, it has been estimated that atherosclerosis leads to approximately 500,000 deaths from coronary artery disease and 150,000 deaths from stroke every year in the United States (American Heart Association, 1996). Percutaneous transluminal angioplasty has become a well-established technique for revascularization of occluded arteries. However, the long-term efficacy of the procedure remains limited by progressive vessel renarrowing (restenosis) within the following few months after angioplasty. Abnormal vascular smooth muscle cell (VSMC) proliferation is thought to play an important role in the pathogenesis of both atherosclerosis and restenosis. Accordingly, considerable effort has been devoted to elucidate the mechanisms that regulate cell cycle progression in VSMCs. In the present article, we will review the different factors that are involved in the control of VSMC proliferation, especially in the context of cardiovascular disease. Ultimately, a thorough understanding of these regulatory networks may lead to the development of novel drug and gene therapies for the treatment of cardiovascular diseases. Therapeutic approaches that targeted specific cell-cycle control genes or growth regulatory molecules which effectively inhibited neointimal lesion formation will be also discussed.

Animals↗
PubMed2000

Inhibition of cellular proliferation by drug targeting of cyclin-dependent kinases.

Abnormal cellular proliferation is associated with the pathology of several diseases, including cancer, atherosclerosis and restenosis post-angioplasty. Therefore, antiproliferative therapies may be a suitable approach to treat these disorders. Candidate targets for such strategies include specific components of the cell cycle machinery. Progression through the cell cycle in mammalian cells requires the activation of several cyclin-dependent protein kinases (CDKs) through their association with regulatory subunits called cyclins. Active CDK/cyclin holoenzymes phosphorylate cellular proteins including the retinoblastoma susceptibility gene product (pRb) and the related pocket proteins p107 and p130. Several compounds have been described that directly or indirectly inhibit the activity of CDKs, which results in a suppression of cell growth. In this review, we will discuss the use of drugs targeting CDKs and their therapeutic application in animal models and clinical trials.

Animals↗
PubMed1999

Antibody blockade of thrombospondin accelerates reendothelialization and reduces neointima formation in balloon-injured rat carotid artery.

BACKGROUND: Remodeling of the extracellular matrix plays an important role during the pathogenesis of atherosclerosis and restenosis. The matrix glycoprotein thrombospondin-1 (TSP1) inhibits endothelial cell proliferation and migration in vitro. In contrast, TSP1 facilitates the growth and migration of cultured vascular smooth muscle cells. Accordingly, we investigated the hypothesis that administration of anti-TSP1 antibody could facilitate reendothelialization and inhibit neointimal thickening in balloon-injured rat carotid artery. METHODS AND RESULTS: Sprague-Dawley rats were subjected to left common carotid artery denudation, after which arteries were treated with C6.7 anti-TSP1 or control antibody. Evans blue dye staining 2 weeks after injury disclosed significantly increased reendothelialization in arteries treated with C6.7 antibody compared with the control group, and this effect was associated with increased number of proliferating cell nuclear antigen-positive endothelial cells. In contrast, treatment with C6.7 antibody decreased the number of proliferating cell nuclear antigen-positive vascular smooth muscle cells in the injured arterial wall. Neointimal thickening was correspondingly attenuated to a statistically significant degree in arteries receiving C6.7 antibody versus the control group at both the 2-week and 4-week time points. CONCLUSIONS: Intra-arterial delivery of antibody against TSP1 facilitated reendothelialization and reduced neointimal lesion formation after balloon denudation.

Angioplasty, Balloon↗
PubMed1999

Vascular smooth muscle cell growth arrest on blockade of thrombospondin-1 requires p21(Cip1/WAF1).

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is thought to play an important role in the pathogenesis of atherosclerosis and restenosis. Previous studies have implicated the extracellular matrix protein thrombospondin-1 (TSP1) in mitogen-dependent proliferation of VSMCs. In this study, we investigated the molecular mechanisms involved in TSP1-mediated regulation of VSMC growth. Neutralizing A4.1 anti-TSP1 antibody inhibited the activity of the G(1)/S cyclin-dependent kinase 2 (cdk2) and blocked the induction of S-phase entry, which normally occurs in serum-stimulated VSMCs. This growth-inhibitory effect was associated with a marked induction of p21(Cip1/WAF1) (p21) expression in A4.1-treated VSMCs. Moreover, addition of A4.1 antibody to VSMCs markedly increased the level of p21 bound to cdk2. Thus growth arrest on antibody blockade of TSP1 may be mediated by the cdk inhibitory protein p21. Consistent with this notion, anti-TSP1 antibody inhibited [(3)H]-thymidine incorporation in wild-type but not in p21-deficient mouse embryonic fibroblasts (MEFs). Together, these data suggest that p21 plays an important role in TSP1-mediated control of cellular proliferation.

Animals↗
PubMed1998

Differential regulation of the retinoblastoma family of proteins during cell proliferation and differentiation.

In the present study we have analysed the regulation of pocket protein expression and post-transcriptional modifications on cell proliferation and differentiation, both in vivo and in vitro. There are marked changes in pocket protein levels during these transitions, the most striking differences being observed between p130 and p107. The mechanisms responsible for regulating pocket protein levels seem to be dependent on both cell type and pocket protein, in addition to their dependence on the cell growth status. Changes in retinoblastoma protein and p107 levels are independent of their state of phosphorylation. However, whereas p130 phosphorylation to forms characteristic of quiescent/differentiated cells results in the accumulation of p130 protein, phosphorylation of p130 to one or more forms characteristic of cycling cells is accompanied by down-regulation of its protein levels. We also show here that the phosphorylation status and protein levels of p130 and p107 are regulated in vivo as in cultured cells. In vivo, changes in p130 forms are correlated with changes in E2F complexes. Moreover, the modulation of p130 and p107 status during cell differentiation in vitro is consistent with the patterns of protein expression and phosphorylation status found in mouse tissues. Thus in addition to the direct disruption of pocket protein/E2F complexes induced by cyclin/cyclin-dependent kinase, the results we report here indicate that the differential modulation of pocket protein levels constitutes a major mechanism that regulates the pool of each pocket protein that is accessible to E2F and/or other transcription factors.

3T3 Cells↗
PubMed1998

Nitric oxide-induced downregulation of Cdk2 activity and cyclin A gene transcription in vascular smooth muscle cells.

BACKGROUND: Nitric oxide (NO) inhibits vascular smooth muscle cell (VSMC) proliferation and neointima formation after balloon injury. However, the molecular mechanisms underlying NO-mediated growth arrest are poorly understood. In the present study, we examined the effects of the NO donors sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) on cell cycle activity in VSMCs. METHODS AND RESULTS: Stimulation of quiescent rat VSMCs with serum leads to an increase in cyclin-dependent kinase (cdk)2 kinase activity that correlates with a marked induction of cyclin A protein expression. The addition of SNP or SNAP to VSMC cultures at the time of serum stimulation abrogates the induction of cdk2 activity without suppressing protein levels of cdk2 or cyclin E. These NO donors block serum-stimulated upregulation of cyclin A mRNA and protein and repress the serum induction of cyclin A promoter activity in VSMCs. CONCLUSIONS: The addition of the nitric oxide donors SNP or SNAP to mitogen-stimulated VSMCs prevents activation of cdk2, a key regulator of the G1 and S phases of the cell cycle. These NO donors do not affect the expression of cdk2 protein but block the mitogen-induced expression of cyclin A, an activating subunit of cdk2. SNP and SNAP also repress the mitogen-stimulated activation of the cyclin A promoter. These data suggest that the antiproliferative effect of NO on VSMCs results, at least in part, from the repression of cyclin A gene transcription.

Animals↗
PubMed1998

Role of c-fos and E2F in the induction of cyclin A transcription and vascular smooth muscle cell proliferation.

Excessive proliferation of vascular smooth muscle cells (VSMCs) contributes to vessel renarrowing after angioplasty. Here we investigated the transcriptional regulation of the cyclin A gene, a key positive regulator of S phase that is induced after angioplasty. We show that Ras-dependent mitogenic signaling is essential for the normal stimulation of cyclin A promoter activity and DNA synthesis in VSMCs. Overexpression of the AP-1 transcription factor c-fos can circumvent this requirement via interaction with the cAMP-responsive element (CRE) in the cyclin A promoter. Moreover, c-fos overexpression in serum-starved VSMCs results in the induction of cyclin A promoter activity in a CRE-dependent manner, and increased binding of endogenous c-fos protein to the cyclin A CRE precedes the onset of DNA replication in VSMCs induced by serum in vitro and by angioplasty in vivo. We also show that E2F function is essential for both serum- and c-fos-dependent induction of cyclin A expression. Taken together, these findings suggest that c-fos and E2F are important components of the signaling cascade that link Ras activity to cyclin A transcription in VSMCs. These studies illustrate a novel link between the transcriptional and cell cycle machinery that may be relevant to the pathogenesis of vascular proliferative disorders.

Activating Transcription Factor 2↗
PubMed1998

Control of vascular smooth muscle and endothelial cell proliferation and its implication in cardiovascular disease.

At homeostasis, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in the arterial wall are fully differentiated and display a very low proliferative index. However, unlike terminally differentiated cells, mature ECs and VSMCs maintain their ability to dedifferentiate and reenter the cell cycle in response to several environmental stimuli. Because of the contribution of EC and VSMC proliferation to the pathogenesis of several diseases, including cancer and cardiovascular disease, considerable effort has been devoted to elucidate the mechanisms that regulate cell cycle progression in these cell types. These regulatory networks and the implications they may have for cardiovascular disease are reviewed here.

Animals↗
PubMed1997

Downregulation of cyclin-dependent kinase 2 activity and cyclin A promoter activity in vascular smooth muscle cells by p27(KIP1), an inhibitor of neointima formation in the rat carotid artery.

Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to intimal hyperplasia during atherosclerosis and restenosis, but the endogenous cell cycle regulatory factors underlying VSMC growth in response to arterial injury are not well understood. In the present study, we report that downregulation of cyclin-dependent kinase 2 (cdk2) activity in serum-deprived VSMCs was associated with the formation of complexes between cdk2 and its inhibitory protein p27(KIP1) (p27). Ectopic overexpression of p27 in serum-stimulated VSMCs resulted in the inhibition of cdk2 activity and repression of cyclin A promoter activity. Collectively, these findings indicate that p27 may contribute to VSMC growth arrest in vitro. Using the rat carotid model of balloon angioplasty, a marked upregulation of p27 was observed in injured arteries. High levels of p27 expression in the media and neointima correlated with downregulation of cdk2 activity at 2 wk after angioplasty, and adenovirus-mediated overexpression of p27 in balloon-injured arteries attenuated neointimal lesion formation. Thus, the inhibition of cdk2 function and repression of cyclin A gene transcription through the induction of the endogenous p27 protein provides a mechanism for the inhibition of VSMC growth at late time points after angioplasty.

Adenoviridae↗