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V Adler

Publications and source records attributed to V Adler.

33 records · Page 2Linked to original sources
PubMed1996

Dose rate and mode of exposure are key factors in JNK activation by UV irradiation.

Single exposure of cells to UVC (254 nm for 30 s) or to UVB (300 nm for 10 min) was shown to activate jun-NH2 kinases which, in turn, phosphorylate their substrates ELK-1, c-jun and ATF-2. While UVC (40-80 J/m2) activates JNK up to 4 h, with maximal induction after 30 min, UVB (150-300 J/m2) activates JNK over a prolonged period, up to 24 h, with maximal induction after 6 h. UV-mediated activation of src-related tyrosine kinases and MAPK revealed different kinetics, with maximal induction after 24 h. As recent studies had indicated a role of a UVC component in mediating the ability of UVB to activate JNK, we have examined the effect of dose rate as well as of multiplicity of exposures on the activation of these kinases. The UVC portion found in 300 J/m2 UVB (5%, corresponding to 15 J/m2, administered within 10 s) did not activate JNK. However, when the same dose was administered at a lower rate (i.e. over 10 min, as needed for UVB irradiation) it was found capable of activating JNK, MAPK and src kinases, but to a lower degree and with different kinetics than found for UVB. Such differences point to cellular changes which are elicited by UVB, but not UVC. Although a single UVB exposure using a filter that blocks wavelengths below 300 nm prevented activation of JNK, multiple exposures of filtered UVB wavelengths (mimicking chronic exposure) were able to activate JNK. We conclude that the mode of UVB exposure (dose rate and multiplicity) is a crucial determinant for physiologically relevant activation of JNK.

3T3 Cells↗
PubMed1996

Impaired jun-NH2-terminal kinase activation by ultraviolet irradiation in fibroblasts of patients with Cockayne syndrome complementation group B.

c-jun-NH2 kinases (JNK) are among the UV-activated protein kinases that play an important role in cellular stress response via the phosphorylation of c-jun, ATF2, and p53. Activation of JNK by UV irradiation requires cooperation between membrane and nuclear components, including DNA lesions per se. The role of DNA lesions in JNK activation led us to explore the inducibility of these kinases in cells of repair-deficient patients. Analyses of primary fibroblast cell lines from patients with Cockayne Syndrome of complementation group B (CS-B) revealed poor JNK activation after UV irradiation in four of five cases when compared with three repair-proficient, normal human fibroblast cell lines. Impaired ability to activate JNK persisted at various time points and with different doses of UV irradiation and coincided with failure of in vitro damaged DNA to activate these kinases. In contrast to UV irradiation, other forms of stress, such as H2O2 or heat shock were capable of inducing JNK activation in CS-B cells. Interestingly, when UV irradiation was administered after osmotic shock, it led to JNK activation in CS-B cells, indicating that alternate signal transduction pathways that are activated in response to other forms of stress can potentiate JNK activation by UV irradiation. Unlike CS-B cells, those of other repair-deficient cells, including xeroderma pigmentosum of different complementation groups, revealed proper activation of JNK by UV irradiation. Together, our findings point to deficiency of JNK activation by UV irradiation in CS-B cells, a phenomenon which may be associated with impaired CS-B, the mutant repair gene in these patients.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1995

Complexes of p21RAS with JUN N-terminal kinase and JUN proteins.

RAS gene-encoded p21 protein has been found to increase in vitro phosphorylation of JUN via its kinase, JUN N-terminal kinase (JNK). This effect is mediated by increased phosphorylation of JNK in the presence of wild-type and oncogenic (Val-12) p21 protein in a dose-dependent manner. Oncogenic p21 protein is more potent in mediating this effect than its normal counterpart. Both normal and oncogenic p21 proteins bind to purified JNK and to JNK that is present in cell extracts from transformed fibroblasts and melanoma cells. Oncogenic and normal p21 proteins have also been found to bind to bacterially expressed JUN protein. This binding is dose dependent, enhanced by the presence of GTP, and depends on the presence of the first 89 amino acids of JUN (the delta domain), as it does not occur with v-jun. While the ability of both normal and oncogenic p21 proteins to bind JNK is strongly inhibited by a p21 peptide corresponding to aa 96-110, and more weakly inhibited by the p21 peptide corresponding to aa 115-126, p21-JUN interaction is inhibited by peptides corresponding to aa 96-110 and, to a lesser degree, by peptides corresponding to aa 35-47. The results suggest that the p21 protein interacts specifically with both JNK and JUN proteins.

3T3 Cells↗
PubMed1995

UV irradiation and heat shock mediate JNK activation via alternate pathways.

To elucidate cellular pathways involved in Jun-NH2-terminal kinase (JNK) activation by different forms of stress, we have compared the effects of UV irradiation, heat shock, and H2O2. Using mouse fibroblast cells (3T3-4A) we show that while H2O2 is ineffective, UV and heat shock (HS) are potent inducers of JNK. The cellular pathways that mediate JNK activation after HS or UV exposure are distinctly different as can be concluded from the following observations: (i) H2O2 is a potent inhibitor of HS-induced but not of UV-induced JNK activation; (ii) Triton X-100-treated cells abolish the ability of UV, but not HS, to activate JNK; (iii) the free radical scavenger N-acetylcysteine inhibits UV- but not HS-mediated JNK activation; (iv) N-acetylcysteine inhibition is blocked by H2O2 in a dose-dependent manner; (v) a Cockayne syndrome-derived cell line exhibits JNK activation upon UV exposure, but not upon HS treatment. The significance of Jun phosphorylation by JNK after treatment with UV, HS, or H2O2 was evaluated by measuring Jun phosphorylation in vivo and also its binding activity in gel shifts. HS and UV, which are potent inducers of JNK, increased the level of c-Jun phosphorylation when this was measured by [32P]orthophosphate labeling of 3T3-4A cultures. H2O2 had no such effect. Although H2O2 failed to activate JNK in vitro and to phosphorylate c-Jun in vivo, all three forms of stress were found to be potent inducers of binding to the AP1 target sequence. Overall, our data indicate that both membrane-associated components and oxidative damage are involved in JNK activation by UV irradiation, whereas HS-mediated JNK activation, which appears to be mitochondrial-related, utilizes cellular sensors.

3T3 Cells↗
PubMed1995

Regulation of AP-3 enhancer activity during hematopoietic differentiation.

Phorbol ester treatment of the human leukemic cell line U937 induces macrophage differentiation over 24-48 hr. This differentiation is mediated by the activation and/or repression of specific gene transcription by proteins, enhancer binding factors, that bind to the DNA upstream of the start site of transcription. We find that differentiation of U937 cells induced by phorbol esters and bryostain 1, activators of protein kinase C, and the phosphatase inhibitor, okadaic acid, stimulates transcription from an enhancer sequence which contains multimerized AP-3 binding sequences but not from one that contains multimerized AP-2 binding motifs. Electrophoretic mobility shift assays (EMSA) demonstrate that AP-3 DNA binding activity peaks at 24 hr, remains elevated for 24 hr, and then decreases thereafter. Southwestern blotting demonstrates that the AP-3 enhancer sequence binds to a 48 kDa protein present in these leukemic cells. Because the AP-3-oligomer also contains an overlapping NF-kappa B-like site, the role of NK-kappa B proteins in regulating transcription from this multimerized oligonucleotide was investigated. Transfection of U937 cells with NF-kappa B family members demonstrated activation of AP-3-mediated transcription by rel A but little effect induced by NFKB1 and c-rel. It is unlikely, however, that phorbol ester-induced transcription from this AP-3 sequence is solely mediated by this NF-kappa B family member since treatment of U937 cells with antisense rel A oligodeoxynucleotides did not block phorbol ester-mediated transcription from the AP-3 site. These data demonstrate that AP-3, but not AP-2 sequences, functions to activate mRNA transcription during phorbol ester-induced hematopoietic differentiation and suggests a complex interaction between NF-kappa B and AP-3 proteins in the regulation of this enhancer element.

Base Sequence↗
PubMed1995

Phosphorylation of transcription factors.

Many transcription factors are regulated by post-translational phosphorylation mechanisms. This chapter described several approaches that have been utilized to examine the phosphorylation of the c-Jun transcription factor. A combination of the techniques described in this chapter can be used to determine whether a transcription factor is phosphorylated in vivo, to analyze the sites of phosphorylation in vitro, and to permit the identification of putative protein kinases that may mediate this phosphorylation in vivo. Proteins labeled with 32P by either in vivo or in vitro techniques can be further analyzed by tryptic phosphopeptide mapping or phosphoamino acid analysis. These procedures have been described in detail elsewhere.

Adenosine Triphosphate↗
PubMed1995

[Clinical significance of autologous transplantation with hematopoietic stem cells in leukemia and solid tumors].

Autologous Transplantation of hematopoietic tissue with frozen hematopoietic stem cells is increasingly used for leukemias and lymphomas, but also for some solid tumors. In the past, autotransplants have been performed with bone marrow as the source of hematopoietic stem cells. Circulating, blood derived hematopoietic stem cells, however, allow safe engraftment of all cell lines after supralethal chemo-radiotherapy. This survey describes the role of autologous stem cell transplantation in disorders that are currently in the center of clinical and scientific interest. This estimation is based on the proportion of protocols dealing with, and centering on, autologous stem cell transplantation in the context of treatment for leukemias and solid tumors ("Oncodisc", "PDQ").

Combined Modality Therapy↗
PubMed1995

jun-NH2-terminal kinase activation mediated by UV-induced DNA lesions in melanoma and fibroblast cells.

jun-NH2-terminal kinase (JNK) belongs to a family of protein kinases that phosphorylates c-Jun, ATF2, and Elk1 in response to various forms of stress including UV irradiation and heat shock. Although in previous studies we have demonstrated the importance of membrane components for JNK activation by UV irradiation, here we have elucidated the role of DNA damage in this response. We show that in vitro-irradiated or sonicated DNA that is added to proteins prepared from UV-treated cells can further induce JNK activation in a dose-dependent manner. When compared with UV-B (300 nm), UV-C (254 nm), which is better absorbed by the DNA, is significantly more potent in activating JNK. Furthermore, when wavelengths lower than 300 nm were filtered out, UV-B was no longer able to activate JNK. With the aid of melanoma and fibroblast cells, which exhibit different resistances to irradiation and require different UV doses to generate the same number of DNA lesions, we demonstrate that above a threshold level of 0.45 lesions and up to 0.75 lesions per 1875 bp, the degree of JNK activation correlates with the amount of lesions induced by UV-C irradiation. Finally, to explore the role of nuclear and mitochondrial DNA (mtDNA) in mediating JNK activation after UV irradiation, we have used cells that lacks mtDNA. Although the lack of mtDNA did not impair the ability of UV to activate JNK, when enucleated, these cells had lost the ability to activate JNK in response to UV irradiation. Overall, our results suggest that DNA damage in the nuclear compartment is an essential component that acts in concert with membrane-anchored proteins to mediate c-Jun phosphorylation by JNK.

3T3 Cells↗
PubMed1994

A peptide encoding the c-Jun delta domain inhibits the activity of a c-jun amino-terminal protein kinase.

Evidence suggests that the c-Jun protooncogene delta (delta) domain (amino acids 31-60) helps regulate the transcriptional activating capacity of c-Jun by modulating the amino-terminal phosphorylation of this protein. By using a peptide encoding the delta domain and purified amino-terminal c-Jun protein kinase, we demonstrate that the delta domain peptide inhibits phosphorylation of the amino terminus of both c-Jun and the related protein JunD. The delta domain peptide inhibited the activation of the c-Jun amino-terminal protein kinase by phorbol esters in permeabilized U937 leukemic cells. Mutation of c-Jun followed by transfection into U937 leukemic cells demonstrated that partial deletions of the delta domain are sufficient to block phosphorylation of the amino terminus of c-Jun. In vitro deletion of the amino-terminal (amino acids 31-44) half of the delta domain inhibited the phosphorylation of c-Jun. However, deletion of the carboxyl-terminal (amino acids 45-60) half only partially inhibited c-Jun phosphorylation. Therefore, these results indicate that the delta domain sequence is an important regulator of c-Jun amino-terminal phosphorylation.

Amino Acid Sequence↗
PubMed1993

Multiple signal transduction pathways mediate c-Jun protein phosphorylation.

A variety of protein kinases, including pp42 and pp54 mitogen-activated protein (MAP) kinases, p34cdc2, and a partially purified protein kinase from 4 beta-phorbol 12-myristate 13 alpha-acetate (PMA)-treated U937 cells have been shown to phosphorylate the NH2-terminal activation domain of c-Jun in vitro. To investigate the role of pp42 MAP kinase in mediating c-Jun phosphorylation in vivo, we have treated U937 monocytic leukemia cells with a variety of pharmacological agents, including PMA, cycloheximide, AIF4, and okadaic acid. Although all of these agents stimulated c-Jun phosphorylation, cycloheximide and okadaic acid had no effect on pp42 MAP kinase phosphorylation, suggesting that MAP kinase activation was not necessary for c-Jun phosphorylation in vivo. Because dominant-negative RasAsn17 has been shown to block the effects of PMA on pp42 MAP kinase phosphorylation, we assessed its effect on c-Jun phosphorylation by cotransfection with a truncated c-Jun construct (c-Jun234). We found that c-Jun234 was expressed only in the cytosol and was inducibly phosphorylated with kinetics similar to those of endogenous nuclear c-Jun. Furthermore, we found that RasAsn17 had no effect on PMA-induced phosphorylation of c-Jun234. Because Ha-Ras requires isoprenylation for membrane binding, we examined the effect of the isoprenylation inhibitors lovastatin and perillic acid on PMA-induced c-Jun phosphorylation. Pretreatment of U937 cells with these agents had no effect on PMA-induced c-Jun or pp42 MAP kinase phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Line↗
PubMed1992

Affinity-purified c-Jun amino-terminal protein kinase requires serine/threonine phosphorylation for activity.

The addition of phorbol esters to U937 leukemic cells stimulates the phosphorylation of c-Jun on serines 63 and 73. To isolate the protein kinase which stimulates this phosphorylation, we have used heparin-Sepharose chromatography followed by affinity chromatography over glutathione-Sepharose beads bound with a fusion protein of glutathione S-transferase and amino acids 5-89 of c-Jun (GST-c-Jun). Using this procedure we purify a 67-kDa protein which is capable of phosphorylating GST-c-Jun as well as the complete c-Jun protein. By making mutations in serines 63 and 73 and then creating a fusion protein with GST (GST-c-Jun mut), we demonstrate that this protein kinase specifically phosphorylates these sites in the c-Jun amino terminus. Treatment of purified c-Jun amino-terminal protein kinase (cJAT-PK) with phosphatase 2A inhibits its ability to phosphorylate GST-c-Jun. This inactivated enzyme can be reactivated by phosphorylation with protein kinase C (PKC), although PKC is not capable of phosphorylating the GST-c-Jun substrate. Because v-Jun cannot be phosphorylated in vivo, we compared the ability of cJAT-PK to bind to GST-v-Jun or GST-c-Jun mut. The cJAT-PK bound 50-fold better to GST-c-Jun mut than GST-v-Jun suggesting that the delta domain which is missing in v-Jun plays a role in binding the cJAT-PK. These results suggest that there is a protein kinase cascade mediated by protein phosphatases and PKC which regulates c-Jun phosphorylation.

Cell Line↗
PubMed1992

Phorbol esters stimulate the phosphorylation of c-Jun but not v-Jun: regulation by the N-terminal delta domain.

c-Jun and its oncogenic counterpart v-Jun are completely conserved within the region from Ser-63 to Ser-73; these serines are sites for phorbol ester-inducible c-Jun phosphorylation. Using a U937 human leukemic cell line stably expressing v-Jun, we have demonstrated that phorbol esters stimulate the in vivo phosphorylation of c-Jun but not v-Jun. We developed an in vitro protein kinase assay to characterize the c-Jun protein kinase and to examine the determinants underlying this differential phosphorylation. Fusion proteins between glutathione S-transferase and the N terminus of c-Jun, v-Jun, or several c-Jun mutants were used as substrates. A c-Jun kinase activity was affinity-purified 5000-fold by using glutathione S-transferase-c-Jun-glutathione-Sepharose beads and was found to phosphorylate the N terminus of c-Jun but not v-Jun or c-Jun containing a 27-amino acid N-terminal deletion found in v-Jun. These effects were also observed in vivo as phorbol 12-myristate 13-acetate did not induce the phosphorylation of v-Jun or the c-Jun deletion mutant in U937 cell lines stably expressing these proteins. These findings indicate that the delta domain of c-Jun (amino acids 34-60), which is deleted in v-Jun, plays a critical role in regulating N-terminal c-Jun phosphorylation.

Amino Acid Sequence↗
PubMed1992

In vivo administration of bryostatin 1, a protein kinase C activator, decreases murine resistance to Salmonella typhimurium.

Bryostatin 1, a potent activator of protein kinase C, has antitumor activity against murine lymphoma, leukemia, and melanoma. In vitro, this compound stimulates the release of gamma-interferon, interleukins, and hematopoietic growth factors from accessory cells and activates both T- and B-cells. Bryostatin 1 is also able to stimulate neutrophils to undergo oxidative burst and degranulation. Because of the ability of this compound to stimulate the immune system, cause release of immune mediators, and activate neutrophils, we have examined its effect on bacterial infection by using the gram-negative bacterium Salmonella typhimurium in mice. We find that animals given injections i.v. of S. typhimurium have a shortened life span if they are also given injections i.p. of nonlethal doses of bryostatin 1. There is a dose-response relationship with 100 micrograms/kg bryostatin 1 having a greater effect on survival than 40 micrograms/kg. Below 40 micrograms/kg there are no effects on survival. Analysis of the first 4 h of Salmonella infection demonstrates that bryostatin 1 does not affect the blood clearance of the bacterium. However, by day 2 of infection greater numbers of bacteria are found in the livers and spleens of mice given injections of bryostatin 1. By day 5, 10-fold more S. typhimurium bacteria are found in the livers and spleens of mice receiving 40 micrograms/kg of bryostatin 1. To determine whether bryostatin 1 was affecting growth or causing the death of bacteria, we used a Salmonella carrying a plasmid which has a temperature-sensitive origin of replication and is unable to replicate when the bacteria are in mice. This experiment demonstrates that bryostatin 1 represses bacterial killing but does not affect bacterial growth. Bryostatin 1 given i.p. stimulates a transient syndrome of weight loss and diarrhea from which the mice recover and regain weight, suggesting that bryostatin 1 may release a number of important humoral mediators in vivo. The weight loss is exacerbated by Salmonella infection with mice receiving bryostatin 1 and S. typhimurium, in that they lose approximately 33% of body weight prior to death. Thus, at doses used to treat murine tumors, bryostatin 1 treatment does not affect the clearance of S. typhimurium from the blood but does decrease the killing of bacteria in the liver and spleen, leading to early animal death. Such potential effects of bryostatin 1 on the outcome of bacterial infections should be evaluated in ongoing human trials of this agent.

Animals↗
PubMed1992

Process measures in interventions for drug-abusing women: from coping to competence.

As a guide to the selection of process and outcome measurement in interventions with drug-abusing women, we have offered a model of fundamental coping processes. Three coping processes--reinforcer management, challenge management, and affect management--appear critical to women's competence and physical hardiness. When these processes go awry, substance abuse is a likely result. For successful recovery from substance abuse, good fortune or purposeful intervention must promote these coping processes. To measure the impact of any intervention with drug-abusing women, methods of assessing fundamental coping processes during intervention (process measures) and repeatedly after intervention (outcome measures) are needed. We have described multiple methods of measuring fundamental coping processes from diverse vantage points: self-report, behavioral observation, biochemistry, and physiology. We have discussed how these measures relate to the theoretical model. Finally, we have indicated measures favored and used in our longitudinal and intervention research on adolescent and perinatal substance abuse. The final set of measures, as summarized in the list of recommended process and outcome measures on pages 324-325, is somewhat lengthy because the process of intervention is complex. Given the financial and structural limitations of research in drug treatment settings, it may not be possible for a single investigator to employ all the recommended measures. An adequate research design would employ two measures from each of the domains outlined. If resources allow, more extensive measurement procedures would be possible.

Adaptation, Psychological↗