Activator protein-1 (AP-1) is an inducible transcription factor that contributes to the generation of chronic inflammation in response to oxidative and electrophilic stress. Previous studies have demonstrated that the PI3K/Akt1 pathway plays an important role in the transcriptional regulation of AP-1 expression. Although the histone post-translational modifications (PTMs) are assumed to affect the AP-1 transcriptional regulation by the PI3K/Akt pathway, the detailed mechanisms are completely unknown. In the present study, we show that heterochromatin 1 gamma (HP1gamma) plays a negative role in TPA-induced c-Jun and c-Fos expression. We show that TPA-induced Akt1 directly phosphorylates HP1gamma, abrogates its suppressive function and increases the interaction between histone H3 and 14-3-3epsilon. Collectively, these our data illustrate that the activation of PI3K/Akt pathway may play a permissive role in the recruitment of histone readers or other coactivators on the chromatin, thereby affecting the degree of AP-1 transcription.
Chromatin ; Heterochromatin ; Histones ; Inflammation ; Phosphorylation* ; Protein Processing, Post-Translational ; Transcription Factor AP-1* ; Transcription Factors

OBJECTIVES: To investigate the distribution of ERa, ERb, c-fos and c-jun in the uterine myoma and myometrium in oder to know how the tamoxifen cause the growth of myoma. METHODS: Myoma and myometrial tissue were obtained from the postmenopausal women treated with tamoxifen in the patients with breast cancer and in the premenopausal patients, who were undergoing myoma of uterus from 1998 through 2000. The espression of each gene was quantitated with quantitative RT-PCR. RESULTS: The expression of ERa was slightly increased in the myoma than the myometrium in the proliferative phase, and was slightly decreased in the myometrium than the myoma in the secretory phase. However it was not significant statistically. In the postmemopausal women treated with tamoxifen, ERa was expressed in all myoma and myometrial tissues and the expression was not statistically significant. The expression of ERb was slightly increased in the myometrium than the leiomyoma in the proliferative and secretory phase, but it was not significant statistically. In the postmemopausal women treated with tamoxifen, the expression of ERb was significantly incresed in the myometrium than the leiomyoma. The expression of c-fos was significantly increased in the myometrium than the leiomyoma in the proliferative and secretory phase. In the postmemopausal women treated with tamoxifen, the expression of c-fos was slightly increased in the leiomyoma than the myometrium, however, it was not statistically significant. CONCLUSION: Tamoxifen may cause the growth of leiomyoma by ERa with AP-1 pathway reducing the counteraction of ERb to ERa.
Animals ; Breast Neoplasms ; Estrogens* ; Female ; Humans ; Leiomyoma ; Mice ; Myoma ; Myometrium ; Tamoxifen* ; Transcription Factor AP-1 ; Uterus

OBJECTIVES: ECS could have therapeutic effects on psychiatric illnesses by inducing IEGs, which in turn regulates expression of their target genes. We observed AP-1 binding activity and identified AP-1 binding proteins in NMDAR1, late response gene of IEGs, which considered as the candidate gene for schizophrenia. METHODS: By gel shift assay and supershift assay, we observed binding activities and AP-1 binding proteins in NMDAR1. Because IEGs are induced rapidly but transiently by external stimuli, there is a possibility that the expression of IEGs is negatively feedbacked by their own products via their AP-1 binding sites. For that purpose, we also observed AP-1 binding activity of c-fos and c-jun via gel shift and supershift assay. RESULTS: ECS increased AP-1 binding activities of NMDAR1 gene, contributed by c-Fos and its related proteins. Peak of the increased binding was 60 minutes in both hippocampus and cerebellum. Though expression of c-Fos and c-Jun were increased by ECS, there were no changes in AP-1 binding activities after ECS. AP-1 sites of IEGs were binded by CREB, regardless of ECS. CONCLUSION: There is a possibility that ECS induced IEG expression, and then incresed expression of NMDR1 by binding of expressed IEGs to the AP-1 site of NMDAR1. ECS did not increase AP-1 binding activities of IEGs. This suggests that the regulation of IEGs' expression can not be influenced mainly by AP-1 site.
Animals ; Binding Sites ; Brain* ; Carrier Proteins ; Cerebellum ; Electroshock* ; Hippocampus ; Rats* ; Schizophrenia ; Transcription Factor AP-1*

Accumulating evidence from epidemiologic and laboratory studies support an inverse relationship between a regular consumption of fruits and vegetables and the risk of specific cancers. Numerous phytochemicals derived from edible plants have been reported to possess ability to interfere with a specific stage of carcinogenic process. Multiple mechanisms have been proposed to account for the anti-carcinogenic actions of dietary constituents, but more attention has recently focussed on intracellular signaling cascades as common molecular targets of a wide variety of chemopreventive phytochemicals.
Chemoprevention ; Fruit ; Mitogen-Activated Protein Kinases ; Phytochemicals* ; Plants, Edible ; Signal Transduction ; Transcription Factor AP-1 ; Transcription Factors* ; Vegetables

CD99 signaling is crucial to a diverse range of biological functions including survival and proliferation. CD99 engagement is reported to augment activator protein-1 (AP-1) activity through mitogen-activated protein (MAP) kinase pathways in a T-lymphoblastic lymphoma cell line Jurkat and in breast cancer cell lines. In this study, we report that CD99 differentially regulated AP-1 activity in the human myeloma cell line RPMI8226. CD99 was highly expressed and the CD99 engagement led to activation of the MAP kinases, but suppressed AP-1 activity by inducing the expression of basic leucine zipper transcription factor, ATF-like (BATF), a negative regulator of AP-1 in RPMI8226 cells. By contrast, engagement of CD99 enhanced AP-1 activity and did not change the BATF expression in Jurkat cells. CD99 engagement reduced the proliferation of RPMI8226 cells and expression of cyclin 1 and 3. Overall, these results suggest novel CD99 functions in RPMI8226 cells.
Breast Neoplasms ; Cell Line* ; Cyclins ; Humans* ; Jurkat Cells ; Leucine Zippers ; Lymphoma ; Multiple Myeloma* ; Phosphotransferases ; Transcription Factor AP-1* ; Transcription Factors

We previously demonstrated that repeated exposure to extremely low frequency magnetic fields (ELF-MF) increases locomotor activity via stimulation of dopaminergic D1 receptor (J. Pharmacol. Sci., 2007;105:367-371). Since it has been demonstrated that activator protein-1 (AP-1) transcription factors, especially 35-kDa fos-related antigen (FRA), play a key role in the neuronal and behavioral adaptation in response to various stimuli, we examined whether repeated ELF-MF exposure induces FRA-immunoreactivity (FRA-IR) in the striatum and nucleus accumbens (striatal complex) of the mice. Repeated exposure to ELF-MF (0.3 or 2.4 mT, 1 h/day, for consecutive fourteen days) significantly induced hyperlocomotor activity and FRA-IR in the striatal complex in a field intensity-dependent manner. ELF-MF-induced FRA-IR lasted for at least 1 year, while locomotor activity returned near control level 3 months after the final exposure to ELF-MF. Pretreatment with SCH23390, a dopaminergic D1 receptor antagonist, but not with sulpiride, a dopaminergic D2 receptor antagonist, significantly attenuated hyperlocomotor activity and FRA-IR induced by ELF-MF. Our results suggest that repeated exposure to ELF-MF leads to prolonged locomotor stimulation and long-term expression of FRA in the striatal complex of the mice via stimulation of dopaminergic D1 receptor.
Animals ; Benzazepines ; Magnetic Fields ; Magnetics ; Magnets ; Mice ; Motor Activity ; Neurons ; Nucleus Accumbens ; Sulpiride ; Transcription Factor AP-1 ; Transcription Factors

In the present study, we first examined whether the changes in the DNA binding activities of the transcription factors, cAMP response element binding protein (CREB) and activator protein-1 (AP-1) mediate the long-term effects of morphine in differentiated SH-SY5Y human neuroblastoma cells. The increases in CREB and AP-1 DNA binding activities were time-dependent up to 6 days of morphine treatment (1, 4, and 6 days). However, the significant reduction in the DNA binding activities of CREB and AP-1 was observed after 10 days of chronic morphine (10 muM) administration. Secondly, we examined whether the changes of CREB and AP-1 DNA binding activities could be modulated by dopamine and haloperidol. Dopamine cotreatment moderately increased the levels of the CREB and AP-1 DNA binding activities induced by 10 days of chronic morphine treatment, and haloperidol cotreatment also resulted in a moderate increase of the CREB and AP-1 DNA binding activities. However, dopamine or haloperidol only treatment showed a significant increase or decrease of the CREB and AP-1 DNA binding activities, respectively. In the case of acute morphine treatment, the CREB and AP-1 DNA binding activities were shown to decrease in a time-dependent manner (30, 60, 90, and 120 min). Taken these together, in differentiated SH-SY5Y cells, morphine tolerance seems to involve simultaneous changes of the CREB and AP-1 DNA binding activities. Our data also suggest the possible involvement of haloperidol in prevention or reversal of morphine tolerance at the transcriptional level.
Cyclic AMP Response Element-Binding Protein ; DNA* ; Dopamine* ; Haloperidol* ; Humans* ; Morphine ; Neuroblastoma* ; Transcription Factor AP-1* ; Transcription Factors

PURPOSE: Hepatocellular carcinoma (HCC), a typical hypervasculized tumor is very sensitive to hypoxia and vascular endothelial growth factor (VEGF) has previously been identified to be up-regulated in response to hypoxia in several cell types. However, the molecular mechanisms by which hypoxia is sensed by the cells remain enigmatic. To investigate whether calcium and AP-1 are involved in hypoxia-sensing mechanism, we performed following experiments. MATERIALS AND METHODS: Hep3B cells were grown in hypoxic condition. To assess cell viability, MTT assay was performed. To investigate the effect of calcium and AP-1, northern blot analysis was performed after treatment with BAPTA/AM. RESULTS: The expression of VEGF was significantly up-regulated by hypoxia in Hep3B, hepatocellular carcinoma cell line. The increased expression of VEGF induced by hypoxia was blocked by the addition of BAPTA/AM, a cytosolic calcium chelator to the media. In addition, we found that the expression of c-jun protooncogene was also up-regulated by hypoxia. Hypoxic increase of c-jun expression was also normalized by the treatment with BAPTA/AM. CONCLUSION: These results suggest that the increased expression of VEGF by hypoxia is mediated through the calcium and c-jun signalling pathway in the Hep3B human hepatoma cell lines.
Anoxia ; Blotting, Northern ; Calcium ; Carcinoma, Hepatocellular* ; Cell Line ; Cell Survival ; Cytosol ; Humans* ; Transcription Factor AP-1 ; Vascular Endothelial Growth Factor A*

Senescence, a stable state of growth arrest, affects many physiological and pathophysiological processes, especially aging. Previous work has indicated that transcription factors (TFs) play a role in regulating senescence. However, a systematic study of regulatory TFs during replicative senescence (RS) using multi-omics analysis is still lacking. Here, we generated time-resolved RNA-seq, reduced representation bisulfite sequencing (RRBS) and ATAC-seq datasets during RS of mouse skin fibroblasts, which demonstrated that an enhanced inflammatory response and reduced proliferative capacity were the main characteristics of RS in both the transcriptome and epigenome. Through integrative analysis and genetic manipulations, we found that transcription factors E2F4, TEAD1 and AP-1 are key regulators of RS. Overexpression of E2f4 improved cellular proliferative capacity, attenuated SA-β-Gal activity and changed RS-associated differentially methylated sites (DMSs). Moreover, knockdown of Tead1 attenuated SA-β-Gal activity and partially altered the RS-associated transcriptome. In addition, knockdown of Atf3, one member of AP-1 superfamily TFs, reduced Cdkn2a (p16) expression in pre-senescent fibroblasts. Taken together, the results of this study identified transcription factors regulating the senescence program through multi-omics analysis, providing potential therapeutic targets for anti-aging.
Aging ; Animals ; Cellular Senescence/genetics* ; E2F4 Transcription Factor/genetics* ; Fibroblasts/metabolism* ; Mice ; TEA Domain Transcription Factors/metabolism* ; Transcription Factor AP-1/metabolism* ; Transcriptome

BACKGROUND: Recently, UVB irradiation was found to activate AP-1, which is known to be a major enhancer factor of the collagenase gene. However, tbe effect of UVA irradiation on the activity of AP 1 in derrnal fibroblasts is unclear. Although all trans-retinoic acid(tRA) has been known to prevent. the AP 1 and collagenase stimulatory effect of UVB irradiation, the effect of tRA and ursolic acid(UsA) on the enhancement of AP-1 activity hy UVA irradiation is unknown. OBJECTIVE: In this stuc y, the effect of UVA irradiation on the AP-1 activity in cultured human dermal fibroblasts was studied. The effect. of tRA and UsA on the enhancement of AP-1 activity by UVA irradiation was also investigated. METHODS: Confluent human dermal fibroblasts were irradiated with 15J/cm of UVA. Drugs were administered and kept in a culture rnedia for 12 hrs before or immediately after UVA irra diation. Nuclear protein extracts were isolated 12 hrs after UVA irradiation and were subjected to gel retardation assay ising oligolabeled DNA probe for AP l binding site. RESULTS: 1. The activity of AP-1 was increased by UVA irradiation and prominent activation was detected at 6 and 12 hrs postirradiation. 2. Compared to the UVA irradiated group, tRA and the high concentration(10(-5)M) of UsA administered before or al ter UVA irradiation inhibited the increase of AP-1 activity. CONCLUSION: These res ilts suggest that UVA irradiation enhance the AP-1 activity, which is known to be a major er hancer factor of the collagenase gene, and tRA and UsA downregulate the 1JVA induced AP-l activity enhancement.
Binding Sites ; Collagenases ; DNA ; Electrophoretic Mobility Shift Assay ; Fibroblasts* ; Humans* ; Nuclear Proteins ; Transcription Factor AP-1* ; Tretinoin*