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1.
Am J Health Syst Pharm ; 80(21): 1557-1563, 2023 10 25.
Article in English | MEDLINE | ID: mdl-37335865

ABSTRACT

PURPOSE: Research pharmacy effort required to safely and compliantly manage investigational products (IP) varies between studies. No validated tool exists in the United States to evaluate these differences in effort. The Vizient Pharmacy Research Committee Investigational Drug Services (IDS) Subcommittee previously developed a systematic complexity scoring tool (CST) through expert consensus to assign a complexity score for pharmacy effort. This project seeks to develop and validate complexity categories based on CST scores. METHODS: Vizient member institutions in IDS assigned a CST complexity score and a perceived complexity category (low, medium, or high) for study initiation and maintenance. Receiver operating characteristic (ROC) curve analysis defined the best CST score cutoff points for each complexity category. Comparing the CST-assigned to the user-perceived complexity category determined whether the CST-assigned complexity category aligned with practitioner assignment. RESULTS: A total of 322 responses were used to determine complexity score categories. The AUC values for study initiation and maintenance were 0.79 (P < 0.001) for the low/medium boundary and 0.80 (P < 0.001) for the medium/high boundary, suggesting the performance of the CST is good. The agreement between CST-assigned and user-perceived complexity categories was 60% for study initiation and 58% for maintenance. The Kendall rank correlation coefficient between the raters and ROC categories was strong, with a value of 0.48 for study initiation and 0.47 for maintenance. CONCLUSION: Development of the CST allows IDS pharmacies to objectively measure the complexity of clinical trials, which is a significant step towards assessing workload and guiding resource allocation.


Subject(s)
Pharmacies , Pharmacy Service, Hospital , Pharmacy , Humans , United States , Drugs, Investigational , Surveys and Questionnaires
2.
PLoS One ; 17(3): e0265218, 2022.
Article in English | MEDLINE | ID: mdl-35294467

ABSTRACT

Using a system optimized for propagating human keratinocytes, culture of skin samples from white and green sturgeons generated epithelial cells capable of making cross-linked protein envelopes. Two distinct forms of TGM1-like mRNA were molecularly cloned from the cells of white sturgeon and detected in green sturgeon cells, accounting for their cellular envelope forming ability. The protein translated from each displayed a cluster of cysteine residues resembling the membrane anchorage region expressed in epidermal cells of teleosts and tetrapods. One of the two mRNA forms (called A) was present at considerably higher levels than the other (called B) in both species. Continuous lines of white sturgeon epidermal cells were established and characterized. Size measurements indicated that a substantial fraction of the cells became enlarged, appearing similar to squames in human epidermal keratinocyte cultures. The cultures also expressed CYP1A, a cytochrome P450 enzyme inducible by activation of aryl hydrocarbon receptor 2 in fish. The cells gradually improved in growth rate over a dozen passages while retaining envelope forming ability, TGM1 expression and CYP1A inducibility. These cell lines are thus potential models for studying evolution of fish epidermis leading to terrestrial adaptation and for testing sturgeon sensitivity to environmental stresses such as pollution.


Subject(s)
Fishes , Transglutaminases , Animals , Epidermal Cells , Fishes/physiology , RNA, Messenger/metabolism , Transglutaminases/genetics , Transglutaminases/metabolism
3.
Sci Rep ; 10(1): 2890, 2020 02 19.
Article in English | MEDLINE | ID: mdl-32076005

ABSTRACT

Inorganic arsenic oxides have been identified as carcinogens in several human tissues, including epidermis. Due to the chemical similarity between trivalent inorganic arsenic (arsenite) and antimony (antimonite), we hypothesized that common intracellular targets lead to similarities in cellular responses. Indeed, transcriptional and proteomic profiling revealed remarkable similarities in differentially expressed genes and proteins resulting from exposure of cultured human epidermal keratinocytes to arsenite and antimonite in contrast to comparisons of arsenite with other metal compounds. These data were analyzed to predict upstream regulators and affected signaling pathways following arsenite and antimonite treatments. A majority of the top findings in each category were identical after treatment with either compound. Inspection of the predicted upstream regulators led to previously unsuspected roles for oncostatin M, corticosteroids and ephrins in mediating cellular response. The influence of these predicted mediators was then experimentally verified. Together with predictions of transcription factor effects more generally, the analysis has led to model signaling networks largely accounting for arsenite and antimonite action. The striking parallels between responses to arsenite and antimonite indicate the skin carcinogenic risk of exposure to antimonite merits close scrutiny.


Subject(s)
Antimony/pharmacology , Arsenites/pharmacology , Epidermis/metabolism , Keratinocytes/metabolism , Signal Transduction , Adrenal Cortex Hormones/metabolism , Colony-Forming Units Assay , Ephrins/metabolism , Gene Expression Profiling , Humans , Keratinocytes/drug effects , Oncostatin M/pharmacology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction/drug effects , Signal Transduction/genetics , Transcription Factors/metabolism
4.
Am J Psychiatry ; 176(11): 957-965, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31537089

ABSTRACT

OBJECTIVE: The authors sought to determine whether targeted treatment of insomnia with controlled-release zolpidem (zolpidem-CR) in suicidal adults with insomnia would provide a reduction in suicidal ideation superior to placebo. METHODS: Reducing Suicidal Ideation Through Insomnia Treatment was an 8-week three-site double-blind placebo-controlled parallel-group randomized controlled trial of zolpidem-CR hypnotic therapy compared with placebo, in conjunction with an open-label selective serotonin reuptake inhibitor. Participants were medication-free 18- to 65-year-olds with major depressive disorder, insomnia, and suicidal ideation. Suicidal ideation was the main outcome, measured first by the Scale for Suicide Ideation and second by the Columbia-Suicide Severity Rating Scale (C-SSRS). RESULTS: A total of 103 participants were randomly assigned to receive zolpidem-CR (N=51) or placebo (N=52) (64 women and 39 men; mean age=40.5 years). Zolpidem-CR had a robust anti-insomnia effect, especially in patients with the most severe insomnia symptoms. No significant treatment effect was observed on the Scale for Suicide Ideation (least squares mean estimate=-0.56, SE=0.83, 95% CI=-2.19, 1.08), but the reduction in scores was significantly positively related to improvement in insomnia after accounting for the effect of other depression symptoms. The C-SSRS indicated that zolpidem-CR had a significant treatment effect (least squares mean estimate=-0.26, SE=0.12, 95% CI=-0.50, -0.02). The advantage for zolpidem-CR in reducing suicidal ideation on the C-SSRS was greater in patients with more severe insomnia. No deaths or suicide attempts occurred. CONCLUSIONS: Although the results do not support the routine prescription of hypnotic medication for mitigating suicidal ideation in all depressed outpatients with insomnia, they suggest that coprescription of a hypnotic during initiation of an antidepressant may be beneficial in suicidal outpatients, especially in patients with severe insomnia.


Subject(s)
Sleep Initiation and Maintenance Disorders/drug therapy , Suicidal Ideation , Zolpidem/therapeutic use , Adolescent , Adult , Aged , Delayed-Action Preparations/therapeutic use , Double-Blind Method , Drug Therapy, Combination/methods , Female , Humans , Male , Middle Aged , Selective Serotonin Reuptake Inhibitors/therapeutic use , Sleep Aids, Pharmaceutical/therapeutic use , Young Adult
5.
J Pediatr Pharmacol Ther ; 22(3): 176-185, 2017.
Article in English | MEDLINE | ID: mdl-28638299

ABSTRACT

Despite its controversial nature, the use of medical marijuana and cannabis-derived medicinal products grows more popular with each passing year. As of November 2016, over 40 states have passed legislation regarding the use of either medical marijuana or cannabidiol products. Many providers have started encountering patients experimenting with cannabis products for a wide range of conditions. While the debate continues regarding these agents for both medicinal and recreational use in the general population, special consideration needs to be made for pediatric use. This review will deliver the history of marijuana use and legislation in the United States in addition to the currently available medical literature to equip pediatric health care providers with resources to provide patients and their parents the best recommendation for safe and appropriate use of cannabis-containing compounds.

6.
PLoS One ; 12(5): e0177016, 2017.
Article in English | MEDLINE | ID: mdl-28472103

ABSTRACT

Among the adaptations of aquatic species during evolution of terrestrial tetrapods was the development of an epidermis preventing desiccation. In present day mammals, keratinocytes of the epidermis, using a membrane-bound transglutaminase (Tgm1), accomplish this function by synthesizing a scaffold of cross-linked protein to which a lipid envelope is attached. This study characterizes the abilities of two homologous transglutaminase isozymes in the teleost fish tilapia to form cross-linked protein structures and their expression in certain tissues. Results indicate they are capable of membrane localization and of generating cellular structures resistant to detergent solubilization. They are both expressed in epithelial cells of the lip, buccal cavity and tips of gill filaments. Adaptation of transglutaminase use in evolution of terrestrial keratinocytes evidently involved refinements in tissue expression, access to suitable substrate proteins and activation of cross-linking during terminal differentiation.


Subject(s)
Transglutaminases/metabolism , Animals , Real-Time Polymerase Chain Reaction , Tilapia
7.
Hosp Pharm ; 52(2): 105-116, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28321137

ABSTRACT

Pharmacists' specialized training and knowledge qualify them to lead and engage in research pertaining to optimal medication use. Performing research promotes pharmacy professionalism and fosters interdisciplinary collaboration. To conduct research appropriately, one must have thorough knowledge of when institutional review board (IRB) approval is required and how to successfully navigate IRB processes. The overarching mission of the IRB overseeing research at an organization per federal guidelines is to protect the rights and welfare of human subjects participating in research. This article discusses the following general pharmacy practice-based considerations relating to IRB processes: strategies for developing research projects, key distinctions between quality improvement and research, practical considerations for submitting IRB applications and documentation, different categories of IRB submission, informed consent and conditions for waivers or alterations of consent, and principal investigator obligations for approved research. Pharmacists should also account for organization-specific IRB processes when designing, submitting, and implementing research projects.

8.
Environ Chem ; 13(6): 963-970, 2016.
Article in English | MEDLINE | ID: mdl-28713220

ABSTRACT

SbIII and AsIII are known to exhibit similar chemical properties, but the degree of similarity in their effects on biological systems merits further exploration. Present work compares the responses of human epidermal keratinocytes, a known target cell type for arsenite-induced carcinogenicity, to these metalloids after treatment for a week at environmentally relevant concentrations. Previous work with these cells has shown that arsenite and antimonite have parallel effects in suppressing differentiation, altering levels of several critical enzymes and maintaining colony forming ability. More globally, protein profiling now reveals parallels in SbIII and AsIII effects. The more sensitive technique of transcriptional profiling also shows considerable parallels. Thus, gene expression changes were almost entirely in the same directions for the two treatments, although the degree of change was sometimes significantly different. Inspection of the changes revealed that RYR1 and LRIG1 were among the genes strongly suppressed, consistent with reduced calcium-dependent differentiation and maintenance of EGF-dependent proliferative potential. Moreover, levels of miRNAs in the cells were altered in parallel, with nearly 90% of the 198 most highly expressed ones being suppressed. Among these was miR-203, which is known to decrease proliferative potential. Finally, both SbIII and AsIII were seen to attenuate bone morphogenetic protein 6 induction of dual specificity phosphatases 2 and 14, consistent with maintaining epidermal growth factor receptor signaling. These findings raise the question whether SbIII, like AsIII, could act as a human skin carcinogen.

9.
Clin Trials ; 12(3): 189-98, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25733676

ABSTRACT

BACKGROUND/AIMS: Suicide is a major public health concern, yet there are very few randomized clinical trials that have been conducted to reduce suicidal ideation in patients at risk of suicide. We describe the rationale and refinements of such a trial that is designed to assess the effect of a hypnotic medication on suicidal ideation in adult outpatients currently experiencing suicidal ideation. METHODS: "Reducing Suicidal Ideation Through Insomnia Treatment" is a multi-site randomized clinical trial that includes three recruiting sites and one data management site. This 4-year study is in its second year of recruitment. The purpose of the study is to compare hypnotic medication versus placebo as an add-on treatment to a selective serotonin reuptake inhibitor as a means of reducing suicidal ideation in depressed adult outpatients with insomnia and suicidal ideation. The safety features of the study follow the 2001 National Institutes of Health guidelines for studies that include patients at risk of suicide. RESULTS: In total, 584 potential participants have undergone telephone screening; 67% of these failed the phone screen, most often due to an absence of expressed suicidal ideation (26% of the telephone screen fails). A total of 115 people appeared for a face-to-face baseline assessment, and 40 of these had completed a taper off of their ineffective psychotropic medications before the baseline assessments. In all, 64% of those who completed baseline assessments failed to proceed to randomization, most commonly because of no clinically significant suicidal ideation (51% of those excluded at baseline). One participant was offered and accepted voluntary psychiatric hospitalization in lieu of study participation. Thus far, 40 participants have been randomized into the study and 88.7% of scheduled visits have been attended, with 93.8% adherence to the selective serotonin reuptake inhibitor and 91.6% adherence to the randomized hypnotic versus placebo. None of the randomized participants have required hospitalization or had a suicide attempt. CONCLUSION: By carefully considering the inclusion and exclusion criteria and other safety features, the safe conduct of randomized clinical trials in suicidal adult patients is possible, including the inclusion of participants who have undergone a prescribed tapering off of psychotropic medications prior to baseline assessment.


Subject(s)
Depressive Disorder, Major/complications , Depressive Disorder, Major/drug therapy , Hypnotics and Sedatives/therapeutic use , Research Design , Selective Serotonin Reuptake Inhibitors/therapeutic use , Suicidal Ideation , Adult , Drug Therapy, Combination , Female , Humans , Hypnotics and Sedatives/administration & dosage , Male , Middle Aged , Patient Safety , Patient Selection , Selective Serotonin Reuptake Inhibitors/administration & dosage , Socioeconomic Factors , United States
10.
J Clin Sleep Med ; 10(12): 1341-2, 2014 Dec 15.
Article in English | MEDLINE | ID: mdl-25325577

ABSTRACT

Akathisia and restless legs syndrome (RLS) share some common clinical features and a common relationship with dopamine dysfunction. However, the underlying causes and appropriate treatments for akathisia and RLS are different. Herein we describe a case of RLS that was precipitated by a single dose of asenapine, which is an atypical antipsychotic, and dissect the features that support the contention that this was indeed a case of RLS and not akathisia.


Subject(s)
Antipsychotic Agents/adverse effects , Heterocyclic Compounds, 4 or More Rings/adverse effects , Restless Legs Syndrome/chemically induced , Diagnosis, Differential , Dibenzocycloheptenes , Female , Humans , Middle Aged , Psychomotor Agitation
11.
Hosp Pharm ; 49(4): 348-54, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24958941

ABSTRACT

Many residency programs have adopted formal training in clinical preceptorship as an additional opportunity for professional development. However, a balance must be struck between acting as a co-preceptor for pharmacy students and as a learner being precepted by a more experienced practitioner. A commonly utilized method for demonstrating skill in the 4 preceptor roles (direct instruction, modeling, coaching, and facilitating) is to co-precept students during a learning experience with the support of a preceptor or experiential mentor. The transition from learner to teacher can present many challenges. Awareness of some of the more common challenges and a review of hypothetical scenarios may promote proactive dialogue with the experienced preceptor and promote confidence as the resident embarks on a co-precepting assignment. The objective of this article is to present scenarios a resident may encounter when co-precepting students, focusing on professionalism, patient care, providing feedback, planning, and communication, and strategies for addressing potential challenges.

12.
Toxicol Appl Pharmacol ; 269(3): 290-6, 2013 Jun 15.
Article in English | MEDLINE | ID: mdl-23566955

ABSTRACT

Arsenic, a human skin carcinogen, suppresses differentiation of cultured keratinocytes. Exploring the mechanism of this suppression revealed that BMP-6 greatly increased levels of mRNA for keratins 1 and 10, two of the earliest differentiation markers expressed, a process prevented by co-treatment with arsenite. BMP also stimulated, and arsenite suppressed, mRNA for FOXN1, an important transcription factor driving early keratinocyte differentiation. Keratin mRNAs increased slowly after BMP-6 addition, suggesting they are indirect transcriptional targets. Inhibition of Notch1 activation blocked BMP induction of keratins 1 and 10, while FOXN1 induction was largely unaffected. Supporting a requirement for Notch1 signaling in keratin induction, BMP increased levels of activated Notch1, which was blocked by arsenite. BMP also greatly decreased active ERK, while co-treatment with arsenite maintained active ERK. Inhibition of ERK signaling mimicked BMP by inducing keratin and FOXN1 mRNAs and by increasing active Notch1, effects blocked by arsenite. Of 6 dual-specificity phosphatases (DUSPs) targeting ERK, two were induced by BMP unless prevented by simultaneous exposure to arsenite and EGF. Knockdown of DUSP2 or DUSP14 using shRNAs greatly reduced FOXN1 and keratins 1 and 10 mRNA levels and their induction by BMP. Knockdown also decreased activated Notch1, keratin 1 and keratin 10 protein levels, both in the presence and absence of BMP. Thus, one of the earliest effects of BMP is induction of DUSPs, which increases FOXN1 transcription factor and activates Notch1, both required for keratin gene expression. Arsenite prevents this cascade by maintaining ERK signaling, at least in part by suppressing DUSP expression.


Subject(s)
Arsenites/pharmacology , Bone Morphogenetic Proteins/antagonists & inhibitors , Keratinocytes/drug effects , Bone Morphogenetic Protein 6/antagonists & inhibitors , Bone Morphogenetic Protein 6/physiology , Bone Morphogenetic Proteins/physiology , Cells, Cultured , Forkhead Transcription Factors/antagonists & inhibitors , Humans , Keratin-1/physiology , Keratin-10/physiology , Keratinocytes/physiology , Real-Time Polymerase Chain Reaction , Receptors, Notch/physiology , Signal Transduction/drug effects
13.
ORNAC J ; 31(4): 13-9, 24-5, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24620505

ABSTRACT

Amputation for paediatric bone cancer is cosmetically and emotionally disturbing. At the Stollery Children's Hospital, in Edmonton, Alberta, families are taken to see their child following amputation but before their child's anaesthetic has been reversed. Through a retrospective study we found that families found this step to be valuable in helping them prepare to support and care for their child post-amputation.


Subject(s)
Amputation, Surgical/psychology , Amputation, Surgical/rehabilitation , Bone Neoplasms/surgery , Caregivers/education , Caregivers/psychology , Parents/education , Parents/psychology , Adolescent , Adult , Alberta , Child , Female , Helping Behavior , Humans , Male , Retrospective Studies , Social Support , Young Adult
14.
Am J Health Syst Pharm ; 68(22): 2176-82, 2011 Nov 15.
Article in English | MEDLINE | ID: mdl-22058104

ABSTRACT

PURPOSE: The results of a 2008 survey by the U.S. Pharmacopeia (USP) Safe Medication Use Expert Committee assessing the use of standardized i.v. drug concentrations at U.S. health care institutions are presented. METHODS: To evaluate progress toward the goal of standardizing and limiting the number of i.v. infusion concentrations of high-risk medications, particularly those commonly used in pediatric patients, a USP-appointed expert committee surveyed a nationally representative sample of hospital and health-system pharmacy directors; 229 usable survey responses and 174 requested lists of routinely used or "standard" concentrations (i.e., those designed to meet the needs of at least 90% of the target adult, pediatric, and neonatal populations) were received. RESULTS: The survey responses indicated that multiple concentrations of high-risk drugs are still commonly used; in some instances, as many as four standard concentrations of a single medication were reported to be in use for a particular age group. Depending on the drug and target group, the proportion of respondents reporting the use of one standard concentration for a given drug ranged from 15% to 79%. The survey data informed and helped focus the USP expert committee's efforts to develop recommended standard concentrations for 10 high-alert drugs. Also presented in this article are general principles drafted by the USP committee to guide the development of local and national standard concentrations. CONCLUSION: The results of a national USP survey indicate that many institutions do not use standard i.v. infusion concentrations of commonly used high-risk medications in adult, pediatric, or neonatal patient populations.


Subject(s)
Medication Errors/prevention & control , Pharmaceutical Solutions/standards , Pharmacy Service, Hospital/standards , Humans , Infusions, Intravenous/standards , Pharmaceutical Solutions/administration & dosage , Pharmacy Service, Hospital/organization & administration , Reference Standards
16.
Mol Carcinog ; 49(4): 398-409, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20082316

ABSTRACT

When cultured human keratinocytes reach confluence, they undergo a program of changes replicating features of differentiation in vivo, including exit from the proliferative pool, increased cell size, and expression of specialized differentiation marker proteins. Previously, we showed that insulin is required for some of these steps and that arsenite, a human carcinogen in skin and other epithelia, opposes the differentiation process. In present work, we show that insulin signaling, probably through the IGF-I receptor, is required for the increase in cell size accompanying differentiation and that this is opposed by arsenite. We further examine the impact of insulin and arsenite on PKCdelta, a known key regulator of keratinocyte differentiation, and show that insulin increases the amount, tyrosine phosphorylation, and membrane localization of PKCdelta. All these effects are prevented by exposure of cells to arsenite or to inhibitors of downstream effectors of insulin (phosphotidylinositol 3-kinase and mammalian target of rapamycin). Retrovirally mediated expression of activated PKCdelta resulted in increased loss of proliferative potential after confluence and greatly increased formation of cross-linked envelopes, a marker of keratinocyte terminal differentiation. These effects were prevented by removal of insulin, but not by arsenite addition. We further demonstrate a role for src family kinases in regulation of PKCdelta. Finally, inhibiting epidermal growth factor receptor kinase activity diminished the ability of arsenite to prevent cell enlargement and to suppress insulin-dependent PKCdelta amount and tyrosine 311 phosphorylation. Thus suppression of PKCdelta signaling is a critical feature of arsenite action in preventing keratinocyte differentiation and maintaining proliferative capability.


Subject(s)
Arsenites/pharmacology , Cell Differentiation/drug effects , Cell Proliferation/drug effects , Insulin/pharmacology , Keratinocytes/drug effects , Cell Line, Transformed , Cell Size/drug effects , Humans , Hypoglycemic Agents/pharmacology , Keratinocytes/cytology , Keratinocytes/metabolism , Protein Kinase C-delta/metabolism , RNA, Messenger/analysis , Signal Transduction/physiology
17.
Toxicol Appl Pharmacol ; 243(3): 275-82, 2010 Mar 15.
Article in English | MEDLINE | ID: mdl-20006635

ABSTRACT

While preserving keratinocyte proliferative ability, arsenite suppresses cellular differentiation markers by preventing utilization of AP1 transcriptional response elements. In present experiments, arsenite had a dramatic effect in electrophoretic mobility supershift analysis of proteins binding to an involucrin promoter AP1 response element. Without arsenite treatment, binding of JunB and Fra1 was readily detected in nuclear extracts from preconfluent cultures and was not detected a week after confluence, while c-Fos was detected only after confluence. By contrast, band shift of nuclear extracts from arsenite treated cultures showed only JunB and Fra1 binding in postconfluent as well as preconfluent cultures. Immunoblotting of cell extracts showed that arsenite treatment prevented the loss of Fra1 and the increase in c-Fos proteins that occurred after confluence in untreated cultures. Chromatin immunoprecipitation assays demonstrated substantial reduction of c-Fos and acetylated histone H3 at the proximal and distal AP1 response elements in the involucrin promoter and of coactivator p300 at the proximal element. Alteration of AP1 transcription factors was also examined in response to treatment with four metal containing compounds (chromate, vanadate, hemin, divalent cadmium) that also suppress involucrin transcription. These agents all influenced transcription at AP1 elements in a transcriptional reporter assay, but exhibited less effect than arsenite on binding activity assessed by mobility shift and chromatin immunoprecipitation and displayed variable effects on AP1 protein levels. These findings help trace a mechanism by which transcriptional effects of arsenite become manifest and help rationalize the unique action of arsenite, compared to the other agents, to preserve proliferative ability.


Subject(s)
Arsenites/pharmacology , Keratinocytes/metabolism , Protein Precursors/biosynthesis , Transcription Factor AP-1/biosynthesis , Blotting, Western , Cell Line, Tumor , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cell Proliferation/drug effects , Cells, Cultured , Chromatin/metabolism , Electrophoretic Mobility Shift Assay , Histones/metabolism , Humans , Immunoprecipitation , Keratinocytes/drug effects , Metals/pharmacology , Promoter Regions, Genetic , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Transfection , p300-CBP Transcription Factors/metabolism
18.
J Invest Dermatol ; 129(1): 155-61, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18633435

ABSTRACT

Arsenic is a well-known human skin carcinogen whose mechanism of action remains to be elucidated. In this work using cultured human epidermal cells, arsenite suppressed accumulation of the transcriptionally active intracellular domain of Notch1. The cells responded to an active peptide from the Notch1 ligand, Jagged1, with increased levels of differentiation marker mRNAs and decreased colony-forming ability. Arsenite suppressed Jagged1 effects and expression of Jagged1 mRNA as well. Moreover, exposure of the cells to a gamma-secretase inhibitor prevented Notch1 processing, decreased cell size and differentiation marker expression, and increased proliferative potential, all effects that occur with arsenite treatment. Thus, arsenite action in suppressing keratinocyte differentiation while maintaining germinative capability could be due to inhibition of Notch1 signaling subsequent to ligand binding. This work also revealed that such arsenite action depends upon epidermal growth factor receptor kinase activity. These findings may help to explain how arsenite, by decreasing generation of the tumor suppressor Notch1, contributes to skin carcinogenesis.


Subject(s)
Arsenites/pharmacology , Keratinocytes/metabolism , Receptor, Notch1/metabolism , Amyloid Precursor Protein Secretases/metabolism , Calcium-Binding Proteins/metabolism , Cell Differentiation , Enzyme Inhibitors/pharmacology , Humans , Insulin-Like Growth Factor I/metabolism , Intercellular Signaling Peptides and Proteins/metabolism , Jagged-1 Protein , Membrane Proteins/metabolism , Models, Biological , Protein Binding , Quinazolines , Receptors, Notch/metabolism , Serrate-Jagged Proteins , Signal Transduction , Skin Neoplasms/metabolism , Tyrphostins/pharmacology
20.
J Invest Dermatol ; 126(11): 2507-15, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16778798

ABSTRACT

This work explores spontaneous immortalization in keratinocytes, derived from two skin samples, that display naturally elevated telomerase activity. Serially passaged with 3T3 feeder layer support, the keratinocytes were examined for colony-forming ability, telomerase activity, telomere length, and finally gene expression using Affymetrix DNA microarrays. The cells initially exhibited normal karyotypes and low colony-forming efficiencies typical of normal epidermal cells, but after 40 passages (approximately 400 generations) colony-forming ability increased markedly, yielding immortalized lines exhibiting a small number of chromosomal aberrations and functionally normal p53. An improved protocol for analysis of microarray data permitted detection of 707 transcriptional changes accompanying immortalization including reduced p16(INK4A) mRNA. Telomerase activity was clearly elevated in cells even at low passage from both samples, and telomerase catalytic subunit mRNA was greatly elevated in those with elevated colony-forming ability. The data raise the possibility of an unusual natural phenotype in which aberrant telomerase regulation extends keratinocyte lifespan until rare variants evade senescence. In addition to revealing a potential tumor-prone syndrome, the findings emphasize the desirability of carefully minimizing the degree or timing of elevated expression of telomerase used to immortalize cells for therapeutic purposes.


Subject(s)
Cellular Senescence/genetics , Epidermis/enzymology , Gene Expression Regulation, Neoplastic , Keratinocytes/enzymology , Telomerase/metabolism , Cells, Cultured , Chromosome Aberrations , Chromosomes, Human/genetics , Epidermal Cells , Gene Expression , Humans , Oligonucleotide Array Sequence Analysis , Protein Biosynthesis/genetics , RNA, Messenger/analysis , RNA, Messenger/metabolism , Telomerase/genetics , Telomere/metabolism
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