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1.
Comp Med ; 67(4): 330-334, 2017 Aug 01.
Article in English | MEDLINE | ID: mdl-28830579

ABSTRACT

Relaxin is a 6-kDa peptide in the insulin superfamily of hormones. In addition to its effects on reproductive and musculoskeletal ligaments, relaxin has demonstrated beneficial effects on cardiac, renal, and vascular systems in preclinical models. The mouse intrapubic ligament ex vivo bioassay is the current standard for measuring in vivo relaxin bioactivity. However, this bioassay necessitates euthanasia and dissection of large cohorts to measure the intrapubic ligament at specified time points. We hypothesized that µCT imaging could be used to reduce the number of animals necessary for the intrapubic ligament bioassay by enabling a single animal to be followed longitudinally throughout the study rather than euthanizing different cohorts at established time points. Female CD1 mice were used to compare µCT imaging with the current standard. Both protocols revealed significant differences in intrapubic ligament length, with the µCT data having greater power when corrected for baseline imaging. From these data, we concluded that using µCT to measure the intrapubic ligament in mice primed with estrogen and dosed with relaxin is a viable refinement and will allow the use of fewer animals in longitudinal studies and provide more robust data, because animals can serve as their own controls.


Subject(s)
Biological Assay/methods , Ligaments/drug effects , Ligaments/diagnostic imaging , Relaxin/administration & dosage , X-Ray Microtomography , Administration, Intravenous , Animals , Estradiol/administration & dosage , Female , Infusion Pumps, Implantable , Infusions, Subcutaneous , Injections, Subcutaneous , Mice , Predictive Value of Tests , Time Factors
2.
Circ J ; 81(6): 888-890, 2017 May 25.
Article in English | MEDLINE | ID: mdl-28420827

ABSTRACT

BACKGROUND: This study determined whether relaxin or matrix metalloproteinase (MMP)-9 influences angiotensin II (AngII)-induced abdominal aortic aneurysms (AAA).Methods and Results:Male C57BL/6 or apolipoprotein E-/-mice were infused with AngII with or without relaxin. Relaxin did not influence AngII-induced AAA in either mouse strain. Infusion of AngII reduced, but relaxin increased, MMP-9 mRNA in macrophages. We then determined the effects of MMP-9 deficiency on AAA in apolipoprotein E-/-mice. MMP-9 deficiency led to AAA formation in the absence of AngII, and augmented AngII-induced aortic rupture and AAA incidence. CONCLUSIONS: MMP-9 deficiency augmented AngII-induced AAA.


Subject(s)
Angiotensin II/adverse effects , Aortic Aneurysm, Abdominal/metabolism , Matrix Metalloproteinase 9/metabolism , Relaxin/biosynthesis , Angiotensin II/pharmacology , Animals , Aortic Aneurysm, Abdominal/chemically induced , Aortic Aneurysm, Abdominal/genetics , Aortic Aneurysm, Abdominal/pathology , Apolipoproteins E/deficiency , Matrix Metalloproteinase 9/genetics , Mice , Mice, Knockout , Relaxin/genetics
3.
Hypertension ; 69(2): 332-338, 2017 02.
Article in English | MEDLINE | ID: mdl-27920129

ABSTRACT

The renal outer medullary potassium (ROMK) channel mediates potassium recycling and facilitates sodium reabsorption through the Na+/K+/2Cl- cotransporter in the loop of Henle and potassium secretion at the cortical collecting duct. Evidence from the phenotype of humans and rodents with functional ROMK deficiency supports the contention that selective ROMK inhibitors (ROMKi) will represent a novel diuretic with potential of therapeutic benefit for hypertension. ROMKi have recently been synthesized by Merck & Co, Inc. The present studies were designed to examine the effects of ROMKi B on systemic hemodynamics, renal function and structure, and vascular function in Dahl salt-sensitive rats. Four experimental groups-control, high-salt diet alone; ROMKi B 3 mg·kg-1·d-1; ROMKi B 10 mg·kg-1·d-1; and hydrochlorothiazide 25 mg·kg-1·d-1-were included in prophylactic (from week 1 to week 9 on high-salt diet) and therapeutic studies (from week 5 to week 9 on high-salt diet), respectively. ROMKi B produced sustained blood pressure reduction and improved renal and vascular function and histological alterations induced by a high-salt diet. ROMKi B was superior to hydrochlorothiazide at reducing blood pressure. Furthermore, ROMKi B provided beneficial effects on both the plasma lipid profile and bone mineral density. Chronic ROMK inhibition not only prevented but also reversed the development of hypertension and end-organ damage in Dahl salt-sensitive rats. Our findings suggest a potential utility of ROMKi B as a novel antihypertensive agent, particularly for the treatment of the salt-sensitive hypertension patient population.


Subject(s)
Acute Kidney Injury/prevention & control , Blood Pressure , Hypertension/prevention & control , Kidney Medulla/metabolism , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Acute Kidney Injury/metabolism , Acute Kidney Injury/physiopathology , Animals , Biomarkers/urine , Disease Models, Animal , Glomerular Filtration Rate , Hypertension/metabolism , Kidney Medulla/drug effects , Potassium Channels, Inwardly Rectifying/metabolism , Rats , Rats, Inbred Dahl
4.
Hypertension ; 62(2): 288-94, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23753405

ABSTRACT

The renal outer medullary potassium channel (ROMK, KCNJ1) mediates potassium recycling and facilitates sodium reabsorption through the Na(+)/K(+)/2Cl(-) cotransporter in the loop of Henle and potassium secretion at the cortical collecting duct. Human genetic studies indicate that ROMK homozygous loss-of-function mutations cause type II Bartter syndrome, featuring polyuria, renal salt wasting, and hypotension; humans heterozygous for ROMK mutations identified in the Framingham Heart Study have reduced blood pressure. ROMK null mice recapitulate many of the features of type II Bartter syndrome. We have generated an ROMK knockout rat model in Dahl salt-sensitive background by using zinc finger nuclease technology and investigated the effects of knocking out ROMK on systemic and renal hemodynamics and kidney histology in the Dahl salt-sensitive rats. The ROMK(-/-) pups recapitulated features identified in the ROMK null mice. The ROMK(+/-) rats, when challenged with a 4% salt diet, exhibited a reduced blood pressure compared with their ROMK(+/+) littermates. More importantly, when challenged with an 8% salt diet, the Dahl salt-sensitive rats with 50% less ROMK expression showed increased protection from salt-induced blood pressure elevation and signs of protection from renal injury. Our findings in ROMK knockout Dahl salt-sensitive rats, together with the previous reports in humans and mice, underscore a critical role of ROMK in blood pressure regulation.


Subject(s)
Blood Pressure , Potassium Channels, Inwardly Rectifying/physiology , Animals , Female , Heterozygote , Kidney/physiology , Male , Phenotype , Potassium Channels, Inwardly Rectifying/genetics , Rats , Rats, Inbred Dahl , Sodium-Potassium-Chloride Symporters/physiology , Solute Carrier Family 12, Member 1
5.
J Immunol ; 185(1): 634-41, 2010 Jul 01.
Article in English | MEDLINE | ID: mdl-20525886

ABSTRACT

The proteasome, a multicatalytic protease, is responsible for the degradation of intracellular proteins. Stimulation of cells with inflammatory cytokines, such as IFN-gamma, leads to the replacement of the constitutive catalytic proteasome subunits by the inducible subunits low molecular mass polypeptide (LMP)2 (beta1i), multicatalytic endopeptidase complex-like-1 (beta2i), and LMP7 (beta5i), which are required for the production of certain MHC class I-restricted T cell epitopes. In this study, we investigated the effect of immunoproteasomes on the development of dextran sulfate sodium-induced colitis. Colitis induction in LMP2-, LMP7-, and multicatalytic endopeptidase complex-like-1-deficient mice caused reduced weight loss compared with wild-type mice. Although colon lengths were shortened in wild-type mice, no reduction was observed in immunoproteasome-deficient mice. In accordance with this, proinflammatory cytokines, such as TNF-alpha and IL-1beta, were not upregulated in these mice. Blockage of LMP7 by a novel LMP7-selective inhibitor (PR-957) strongly reduced pathological symptoms of dextran sulfate sodium-induced colitis. Production of numerous cytokines in PR-957-treated mice was suppressed, resulting in reduced inflammation and tissue destruction. Taken together, these results demonstrate that an immunoproteasome-specific inhibitor can be used to attenuate autoimmune diseases like colitis.


Subject(s)
Colitis, Ulcerative/immunology , Colitis, Ulcerative/prevention & control , Oligopeptides/administration & dosage , Proteasome Inhibitors , Animals , Autoimmune Diseases/enzymology , Autoimmune Diseases/prevention & control , Colitis, Ulcerative/enzymology , Disease Models, Animal , Female , Mice , Mice, Inbred C57BL , Mice, Knockout , Oligopeptides/therapeutic use , Proteasome Endopeptidase Complex/biosynthesis , Proteasome Endopeptidase Complex/deficiency , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/physiology , Up-Regulation/immunology
6.
J Med Chem ; 52(9): 3028-38, 2009 May 14.
Article in English | MEDLINE | ID: mdl-19348473

ABSTRACT

Proteasome inhibition has been validated as a therapeutic modality in the treatment of multiple myeloma and non-Hodgkin's lymphoma. Carfilzomib, an epoxyketone currently undergoing clinical trials in malignant diseases, is a highly selective inhibitor of the chymotrypsin-like (CT-L) activity of the proteasome. A chemistry effort was initiated to discover orally bioavailable analogues of carfilzomib, which would have potential for improved dosing flexibility and patient convenience over intravenously administered agents. The lead compound, 2-Me-5-thiazole-Ser(OMe)-Ser(OMe)-Phe-ketoepoxide (58) (PR-047), selectively inhibited CT-L activity of both the constitutive proteasome (beta5) and immunoproteasome (LMP7) and demonstrated an absolute bioavailability of up to 39% in rodents and dogs. It was well tolerated with repeated oral administration at doses resulting in >80% proteasome inhibition in most tissues and elicited an antitumor response equivalent to intravenously administered carfilzomib in multiple human tumor xenograft and mouse syngeneic models. The favorable pharmacologic profile supports its further development for the treatment of malignant diseases.


Subject(s)
Dipeptides/chemical synthesis , Dipeptides/pharmacology , Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Oligopeptides/chemical synthesis , Oligopeptides/pharmacology , Proteasome Inhibitors , Thiazoles/chemical synthesis , Thiazoles/pharmacology , Administration, Oral , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Biological Availability , Cell Line , Dipeptides/chemistry , Dipeptides/pharmacokinetics , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Humans , Kinetics , Mice , Oligopeptides/chemistry , Oligopeptides/pharmacokinetics , Structure-Activity Relationship , Substrate Specificity , Thiazoles/chemistry , Thiazoles/pharmacokinetics
7.
Cancer Res ; 67(13): 6383-91, 2007 Jul 01.
Article in English | MEDLINE | ID: mdl-17616698

ABSTRACT

Clinical studies with bortezomib have validated the proteasome as a therapeutic target for the treatment of multiple myeloma and non-Hodgkin's lymphoma. However, significant toxicities have restricted the intensity of bortezomib dosing. Here we describe the antitumor activity of PR-171, a novel epoxyketone-based irreversible proteasome inhibitor that is currently in clinical development. In comparison to bortezomib, PR-171 exhibits equal potency but greater selectivity for the chymotrypsin-like activity of the proteasome. In cell culture, PR-171 is more cytotoxic than bortezomib following brief treatments that mimic the in vivo pharmacokinetics of both molecules. Hematologic tumor cells exhibit the greatest sensitivity to brief exposure, whereas solid tumor cells and nontransformed cell types are less sensitive to such treatments. Cellular consequences of PR-171 treatment include the accumulation of proteasome substrates and induction of cell cycle arrest and/or apoptosis. Administration of PR-171 to animals results in the dose-dependent inhibition of the chymotrypsin-like proteasome activity in all tissues examined with the exception of the brain. PR-171 is well tolerated when administered for either 2 or 5 consecutive days at doses resulting in >80% proteasome inhibition in blood and most tissues. In human tumor xenograft models, PR-171 mediates an antitumor response that is both dose and schedule dependent. The antitumor efficacy of PR-171 delivered on 2 consecutive days is stronger than that of bortezomib administered on its clinical dosing schedule. These studies show the tolerability, efficacy, and dosing flexibility of PR-171 and provide validation for the clinical testing of PR-171 in the treatment of hematologic malignancies using dose-intensive schedules.


Subject(s)
Antineoplastic Agents/pharmacology , Oligopeptides/pharmacology , Proteasome Endopeptidase Complex/metabolism , Animals , Apoptosis , Boronic Acids/pharmacology , Bortezomib , Chymotrypsin/metabolism , Chymotrypsin/pharmacology , Dose-Response Relationship, Drug , Humans , Inhibitory Concentration 50 , Male , Mice , Neoplasm Transplantation , Pyrazines/pharmacology , Rats , Rats, Sprague-Dawley
8.
Gut ; 56(4): 524-33, 2007 Apr.
Article in English | MEDLINE | ID: mdl-16950831

ABSTRACT

BACKGROUND: Nuclear factor-kappaB (NF-kappaB) is a key transcriptional regulator of inflammatory bowel disease (IBD). AIM: To investigate the therapeutic potential of a locally administered "non-viral" nuclear factor-kappaB decoy (NFkappaBD) in multiple experimental models of IBD. METHODS: A fully phosphorothioated decoy oligonucleotide with improved stability that specifically binds NF-kappaB and blocks inflammatory mediators regulated by this transcription factor without the help of viral envelope-assisted delivery was developed. The therapeutic effects of NFkappaBD were studied in the trinitrobenzene sulphonic acid, oxazolone and dextran sodium sulphate induced colitis models. RESULTS: Intracolonic administration of NFkappaBD results in the delivery of NFkappaBD to inflammatory cells and a reduction of NF-kappaB heterodimers. In the T helper cell 1-driven trinitrobenzene sulphonic acid-induced colitis model, mice receiving NFkappaBD treatment exhibit a dose-dependent reduction in disease severity and a more rapid recovery to normal body weight, similar to a clinically relevant dose of budesonide. Clinical efficacy was corroborated by considerable reductions in colitis pathology and tissue levels of several pro-inflammatory markers, including tumour necrosis factor alpha, interleukin 6, interleukin 1beta and monocyte chemotactic protein 1. NFkappaBD also mitigates disease activity in the T helper cell 2-like oxazolone colitis and epithelial injury-related acute dextran sodium sulphate colitis models. Interestingly, restoration of tissue homeostasis is observed in NFkappaBD-treated animals with the rapid re-emergence of functional goblet cells and a return to normal patterns of cell proliferation in the mucosal epithelium and smooth muscle cell layers. CONCLUSIONS: These data support the potential use of "naked" NFkappaBD as a cross-functional therapeutic in IBD, and show for the first time that it can facilitate the restoration of colon homeostasis and function.


Subject(s)
Genetic Therapy/methods , Inflammatory Bowel Diseases/therapy , Oligodeoxyribonucleotides/administration & dosage , Animals , Colon/metabolism , Dextran Sulfate , Disease Models, Animal , Female , Gene Transfer Techniques , Homeostasis/drug effects , Inflammation Mediators/metabolism , Inflammatory Bowel Diseases/chemically induced , Inflammatory Bowel Diseases/metabolism , Inflammatory Bowel Diseases/pathology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Microscopy, Confocal , NF-kappa B/metabolism , Oligodeoxyribonucleotides/therapeutic use , Oxazolone , Trinitrobenzenesulfonic Acid
9.
J Invest Dermatol ; 126(8): 1792-803, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16628194

ABSTRACT

Atopic dermatitis (AD) is a common chronic skin inflammatory disease. Long-term use of topical corticosteroids in skin inflammation poses risks of systemic and local side effects. The NF-kappaB transcription factor family plays a central role in the progression and maintenance of AD. This study explores the possibility of using topical NF-kappaB Decoy as a novel therapeutic alternative for targeting Th1/Th2-driven skin inflammation in experimental AD. A high-affinity, topical NF-kappaB Decoy developed for human efficacy demonstrates: (i) efficient NF-kappaB Decoy penetration in pig skin, (ii) NF-kappaB Decoy nuclear localization in keratinocytes and key immune cells, and (iii) potent "steroid-like" efficacy in a chronic dust-mite antigen skin inflammation treatment model. NF-kappaB Decoy exerts its anti-inflammatory action through the effective inhibition of essential regulators of inflammation and by induction of apoptosis of key immune cells. Unlike betamethasone valerate (BMV), long-term NF-kappaB Decoy treatment does not induce skin atrophy. Moreover, topical NF-kappaB Decoy, in contrast to BMV, restores compromised stratum corneum integrity and barrier function. Steroid withdrawal causes rapid rebound of inflammation, while the NF-kappaB Decoy therapeutic benefit was maintained for weeks. Thus, topical NF-kappaB Decoy provides a novel mechanism of reducing chronic skin inflammation with improved skin homeostasis and minimal side effects.


Subject(s)
Dermatitis, Atopic/drug therapy , Immunosuppressive Agents/administration & dosage , Oligodeoxyribonucleotides/administration & dosage , Skin/drug effects , Administration, Topical , Animals , Apoptosis/drug effects , Apoptosis/immunology , Atrophy , Cell Division/drug effects , Cell Division/immunology , Dermatitis, Atopic/immunology , Dermatitis, Atopic/pathology , Ear, External , Edema/drug therapy , Edema/immunology , Male , Mice , Mice, Inbred Strains , Ointments , Permeability/drug effects , Skin/immunology , Skin/pathology
10.
Proc Natl Acad Sci U S A ; 101(5): 1223-8, 2004 Feb 03.
Article in English | MEDLINE | ID: mdl-14745015

ABSTRACT

Now that the human genome has been sequenced, the challenge of assigning function to human genes has become acute. Existing approaches using microarrays or proteomics frequently generate very large volumes of data not directly related to biological function, making interpretation difficult. Here, we describe a technique for integrative systems biology in which: (i) primary cells are cultured under biologically meaningful conditions; (ii) a limited number of biologically meaningful readouts are measured; and (iii) the results obtained under several different conditions are combined for analysis. Studies of human endothelial cells overexpressing different signaling molecules under multiple inflammatory conditions show that this system can capture a remarkable range of functions by a relatively small number of simple measurements. In particular, measurement of seven different protein levels by ELISA under four different conditions is capable of reconstructing pathway associations of 25 different proteins representing four known signaling pathways, implicating additional participants in the NF-kappaBorRAS/mitogen-activated protein kinase pathways and defining additional interactions between these pathways.


Subject(s)
Signal Transduction/physiology , Cells, Cultured , Endothelial Cells/metabolism , Humans , Interferon-gamma/pharmacology , Interleukin-1/pharmacology , MAP Kinase Signaling System , Tumor Necrosis Factor-alpha/pharmacology
12.
Nature ; 421(6923): 639-43, 2003 Feb 06.
Article in English | MEDLINE | ID: mdl-12571598

ABSTRACT

The nuclear factor NF-kappaB and oncogenic Ras can alter proliferation in epidermis, the most common site of human cancer. These proteins are implicated in epidermal squamous cell carcinoma in mice, however, the potential effects of altering their function are uncertain. Whereas inhibition of NF-kappaB enhances apoptosis in certain tumours, blockade of NF-kappaB predisposes murine skin to squamous cell carcinoma. Because therapeutics inhibiting Ras and NF-kappaB pathways are being developed to treat human cancer, it is essential to assess the effects of altering these regulators. The medical relevance of murine studies is limited, however, by differences between mouse and human skin, and by the greater ease of transforming murine cells. Here we show that in normal human epidermal cells both NF-kappaB and oncogenic Ras trigger cell-cycle arrest. Growth arrest triggered by oncogenic Ras can be bypassed by IkappaBalpha-mediated blockade of NF-kappaB, generating malignant human epidermal tissue resembling squamous cell carcinoma. Human cell tumorigenesis is dependent on laminin 5 and alpha6beta4 integrin. Thus, IkappaBalpha circumvents restraints on growth promotion induced by oncogenic Ras and can act with Ras to induce invasive human tissue neoplasia.


Subject(s)
Epidermis/pathology , Keratinocytes/metabolism , Keratinocytes/pathology , NF-kappa B/antagonists & inhibitors , Neoplasms/metabolism , Neoplasms/pathology , Oncogene Protein p21(ras)/metabolism , Animals , Apoptosis , Cell Adhesion Molecules/metabolism , Cell Division , Cyclin-Dependent Kinases/metabolism , Epidermis/enzymology , Epidermis/metabolism , Genes, ras/genetics , Humans , I-kappa B Proteins/genetics , I-kappa B Proteins/metabolism , Integrin alpha6beta4/metabolism , Keratinocytes/enzymology , Keratinocytes/transplantation , Mice , Mice, Nude , Mice, SCID , NF-KappaB Inhibitor alpha , NF-kappa B/chemistry , NF-kappa B/genetics , NF-kappa B/metabolism , Neoplasm Invasiveness , Neoplasms/enzymology , Neoplasms/genetics , Oncogene Protein p21(ras)/genetics , Telomere/genetics , Telomere/metabolism , Transduction, Genetic , Kalinin
13.
Cancer Res ; 63(2): 319-23, 2003 Jan 15.
Article in English | MEDLINE | ID: mdl-12543782

ABSTRACT

Ras effects vary with developmental setting, with oncogenic RAS activation implicated in epithelial carcinogenesis. In epidermal cells, previous studies described conflicting Ras impacts on growth and differentiation, with the only in vivo studies relying on constitutive alterations of Ras function throughout development. To study Ras effects in developmentally mature adult epidermis, we expressed a 4-hydroxytamoxifen (4OHT)-regulated Ras fusion in transgenic mice using the keratin 14 promoter. Resulting adult K14-ER:Ras mice displayed 4OHT-inducible activation of Ras as well as elements of Raf/mitogen-activated protein kinase (MAPK) but not RalGDS/Ral or phosphatidylinositol 3'-kinase (PI3K)/Akt downstream Ras effector pathways. Ras reversibly induced massive cutaneous hyperplasia and suppressed differentiation. Ras-driven hyperproliferation was accompanied by increases in beta1 and beta4 integrin epidermal progenitor markers. Epidermal expression of inducible Raf produced similar changes. These findings indicate that activation of Ras in adult epidermis promotes proliferation and inhibits differentiation and that Raf is sufficient to mediate these effects.


Subject(s)
Proto-Oncogene Proteins c-raf/metabolism , Skin/enzymology , Tamoxifen/analogs & derivatives , ras Proteins/metabolism , Animals , Cell Differentiation/physiology , Cell Division/physiology , Humans , Immunohistochemistry , MAP Kinase Signaling System/physiology , Mice , Mice, Transgenic , Proto-Oncogene Proteins c-raf/biosynthesis , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Skin/cytology , Skin/metabolism , Tamoxifen/pharmacology , ras Proteins/biosynthesis
14.
Nat Med ; 8(10): 1105-14, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12357246

ABSTRACT

Ras acts with other proteins to induce neoplasia. By itself, however, strong Ras signaling can suppress proliferation of normal cells. In primary epidermal cells, we found that oncogenic Ras transiently decreases cyclin-dependent kinase (CDK) 4 expression in association with cell cycle arrest in G1 phase. CDK4 co-expression circumvents Ras growth suppression and induces invasive human neoplasia resembling squamous cell carcinoma. Tumorigenesis is dependent on CDK4 kinase function, with cyclin D1 required but not sufficient for this process. In facilitating escape from G1 growth restraints, Ras and CDK4 alter the composition of cyclin D and cyclin E complexes and promote resistance to growth inhibition by INK4 cyclin-dependent kinase inhibitors. These data identify a new role for oncogenic Ras in CDK4 regulation and highlight the functional importance of CDK4 suppression in preventing uncontrolled growth.


Subject(s)
Cyclin-Dependent Kinases/metabolism , Epidermis/metabolism , Epidermis/pathology , Proto-Oncogene Proteins , ras Proteins/metabolism , Animals , Cadherins/metabolism , Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/pathology , Cell Cycle/physiology , Cells, Cultured , Cyclin D1/metabolism , Cyclin E/metabolism , Cyclin-Dependent Kinase 4 , Cyclin-Dependent Kinases/genetics , Endothelial Growth Factors/metabolism , Epidermal Cells , Gene Transfer Techniques , Genes, Reporter , Humans , Intercellular Signaling Peptides and Proteins/metabolism , Keratinocytes/metabolism , Lung/pathology , Lymphokines/metabolism , Mice , Mitogen-Activated Protein Kinases/metabolism , Recombinant Fusion Proteins/metabolism , Skin Neoplasms/metabolism , Skin Neoplasms/pathology , Telomere/metabolism , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors , ras Proteins/genetics
15.
Oncogene ; 21(10): 1527-38, 2002 Feb 28.
Article in English | MEDLINE | ID: mdl-11896581

ABSTRACT

While important in carcinogenesis, the role of Ras in normal self-renewing tissues such as epidermis is unclear. To address this, we altered Ras function in undifferentiated and differentiating epidermal layers. Ras blockade within undifferentiated basal epidermal cells leads to decreased integrin expression, diminished growth capacity and induction of differentiation. Ras blockade in post-mitotic suprabasal epidermis exerts no effect. In contrast, regulated Ras and Raf activation inhibits differentiation. These findings indicate that spatially restricted Ras/Raf signaling divides epidermis into an undifferentiated proliferative compartment and a differentiating post-mitotic compartment and suggest a new role for Ras in tissue homeostasis.


Subject(s)
Epidermis/metabolism , Proto-Oncogene Proteins p21(ras)/antagonists & inhibitors , Proto-Oncogene Proteins p21(ras)/physiology , Animals , Cell Differentiation , Cell Division , Cells, Cultured , Epidermal Cells , Humans , Immunohistochemistry , Integrins/immunology , Integrins/metabolism , Keratinocytes/metabolism , Mice , Mice, Transgenic , Microscopy, Fluorescence , Models, Biological , Mutation , Proto-Oncogene Proteins c-raf/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Signal Transduction
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