• Journal of Life Science
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• v.13 no.4
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• pp.441-447
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• 2003

To examine the role of protein kinase C (PKC) in regulation of interleukin-1 beta (IL-1$\beta$)-induced iNOS expression, IL-1$\beta$-induced nitrite production was observed in cultured vascular smooth muscle (VSM) cells pretreated with phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-butyrate (PDB) as PKC activator; 4$\alpha$-phorbol-didecanoate (PDD) as PKC non-activator. Nitrite production induced by IL-1$\beta$ was increased by the presence of increasing concentration of PMA ranging from 2 to 200 nM. However, in VSM cells pretreated with PMA and PDB, IL-1$\beta$-induced $NO_2$ production was decreased in proportion to the duration of pretreatment, and most significantly decreased in pretreatment time of 24 hours. Using RT-PCR method, the expression of iNOS mRNA induced by IL-1$\beta$ was decreased in VSM cells pretreated with PMA 200 nM for 24 hours. These results suggest that decrease in IL-I$\beta$-induced nitrite production by the pretreatment of PMA result from inhibition of iNOS expression and the inhibition related to PMA-induced PKC down-regulation.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.47-53
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• 1996

We examined the expression of the heat shock proteins (HSPs) and glucose-regulated proteins (GRPs) during phorbol 1 2-myristate 1 3-acetate (PMA)-induced megakaryocytic differentiation of human er"'throleukemia K562 cells. PMA-treated K562 cells showed a cell growth arrest and alteration in morphology and patterns of gpllIa and c-myc expression, characteristic of megakaryocytic differentiation. During the megakaryocytic differentiation, HSP9OA, HSP9OB, and HSP28 mRNA and protein levels markedly decreased, while GRP78/B and GRP94 mRNA levels were enhanced. On the other hand, HSP7OA and HSP7OB mRNA levels were reduced, but HSP7O protein levels were not changed by PMA treatment. These results suggest specific roles for the HSPs and GRPs in K562 cell proliferation and megakaryocic differentiation.tion.

• Journal of Life Science
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• v.22 no.1
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• pp.87-91
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• 2012

Phorbol 12-myristate 13-acetate (PMA), a known tumor-promoting phorbol ester, activates the signal transduction enzyme protein kinase C (PKC) in animal cells. We investigated the effect of PMA on the regulation of gravitropism via ethylene production in primary roots of maize. PMA stimulated root growth and the gravitropic response in a concentration-dependent manner at $10^{-6}$ M and $10^{-4}$ M over 8 hrs. These effects were prevented by treatment with staurosporine (STA), a potent inhibitor of PKC. These results support the possibility that the gravitropic response might be regulated through protein kinases that are involved in the signal transduction system. Ethylene is known to play a role in the regulation of root growth and gravitropism. Ethylene production was increased by about 26% and 37% of the control rate in response to $10^{-6}$ M and $10^{-4}$ M PMA, respectively. PMA also stimulated the activity of ACC synthase (ACS), which converts the S-adenosyl-L-methionine (AdoMet) to 1-aminocyclopropane-1-carboxylic acid (ACC) in the ethylene production pathway. These effects on ethylene production were also prevented by STA treatment. These results suggest that the root gravitropic response in maize is regulated through protein kinases via ethylene production.

• Journal of Life Science
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• v.18 no.7
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• pp.952-957
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• 2008

We evaluated the effects of various factors (e.g., serum, inhibitors of protein synthesis, and cytoskeleton and protein kinases) on early PMA-induced THP-1 cell adhesion using an adhesion assay with Sulforhodamine B (SRB) staining, which was used to assess the proliferation of the attached cells. THP-1 cell adhesion to a plastic substrate was detected 1 hr after exposure to Phorbol 12-Myristate 13-Acetate (PMA) and peaked after 18 hr. At concentrations > 25 nM PMA, the level of adhesion did not change. Based on our preliminary results, we used 25 nM PMA and 5 hr of culture as standard assay conditions. Early PMA-induced cell adhesion was not affected by the presence of serum or PD 98059 in the culture medium, but was affected by the addition of PKC inhibitors and cycloheximide. In the presence of actin inhibitor with PMA, the cell adhesion increased when comparing with PMA treatment only. Thus, early PMA-induced adhesion of THP-1 cells does not require serum in the culture medium, MAP-kinase activation, or actin polymerization, but does require de novo protein synthesis and PKC activation. Our SRB-based cell adhesion assay may be used to screen other PKC inhibitors.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.51-56
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• 2013

Many intracellular proteins and signaling cascades contribute to the sensitivity of N-methyl-D-aspartate receptors (NMDARs). One such putative contributor is the serine/threonine kinase, protein kinase C (PKC). Activation of PKC by phorbol 12-myristate 13-acetate (PMA) causes activation of extracellular signal-regulated kinase (ERK) and promotes the formation of new spines in cultured hippocampal neurons. The purpose of this study was to examine which PKC isoforms are responsible for the PMA-induced augmentation of long-term potentiation (LTP) in the CA1 stratum radiatum of the hippocampus in vitro and verify that this facilitation requires NMDAR activation. We found that PMA enhanced the induction of LTP by a single episode of theta-burst stimulation in a concentration-dependent manner without affecting to magnitude of baseline field excitatory postsynaptic potentials. Facilitation of LTP by PMA (200 nM) was blocked by the nonspecific PKC inhibitor, Ro 31-8220 ($10{\mu}M$); the selective $PKC{\delta}$ inhibitor, rottlerin ($1{\mu}M$); and the $PKC{\varepsilon}$ inhibitor, TAT-${\varepsilon}V1$-2 peptide (500 nM). Moreover, the NMDAR blocker DL-APV ($50{\mu}M$) prevented enhancement of LTP by PMA. Our results suggest that PMA contributes to synaptic plasticity in the nervous system via activation of $PKC{\delta}$ and/or $PKC{\varepsilon}$, and confirm that NMDAR activity is required for this effect.

• BMB Reports
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• v.36 no.5
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• pp.520-523
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• 2003

The proliferation and differentiation signals of myelogeneous U937 cells are provided by extracellular stimuli, such as lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA). In a DNA-native-polyacrylamide gel assay system, we demonstrated that a particular nuclease activity is expressed in PMA-stimulated U937 cells and secreted into the culture medium. The nuclease activity was induced in U937 cells by LPS treatment, while the secretion of the enzyme was undetected in the culture medium. Therefore, it is likely that the expression and secretion of the particular nuclease in U937 cells are controlled by extracellular stimulations, such as PMA and LPS treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.2
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• pp.157-163
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• 2020

Chronic inflammatory airway diseases, such as chronic rhinosinusitis, chronic obstructive pulmonary disease, and asthma, are associated with excessive mucus production. Hence, the regulation of mucus production is important for the treatment of upper and lower airway diseases. Eupatilin is a pharmacologically active ingredient obtained from Artemisia asiatica Nakai (Asteraceae) and exerts potent anti-inflammatory, anti-allergic, and anti-tumor activities. In the present study, we investigated the effect of eupatilin on phorbol 12-myristate 13-acetate (PMA)-induced MUC5AC and MUC5B expression in human airway epithelial cells. We found that eupatilin treatment significantly inhibited PMA-induced mucus secretion in PAS staining. In addition, qRT-PCR results showed that eupatilin dose-dependently decreased the mRNA expression of MUC5AC in human airway epithelial cells. Western blot and immunofluorescence assay also showed that PMA-induced protein expression of MUC5AC was inhibited by eupatilin treatment. Finally, we investigated MAPKs activity after stimulation with PMA using western blot analysis in human airway epithelial cells. The results showed that eupatilin downregulated the levels of phosphorylated p38, ERK, and JNK. In summary, the anti-inflammatory activities of eupatilin, characterized as the suppression of MUC5AC expression and secretion in human airway epithelial cells, were found to be associated with the inhibition of p38/ERK/JNK MAPKs signaling pathway of MUC5AC secretion.

• Nutritional Sciences
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• v.9 no.3
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• pp.145-151
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• 2006

Matrix metalloproteinases (MMP) play an important role in the extracellular matrix (ECM) degradation undetphysiological and pathological conditions. The present study examined the influence of (-)epigallocatechin gallate and quercetin on phorbol-12-myristate 13-acetate (PMA)-induced secretion of MMP-2 and MMP-9, when human umbilical vein endothelial cells (HUVEC) were treated with (-)epigallocatechin gallate and quercetin at supraphysiological concentrations of $25{\mu}mol/L$. No cytotoxicity was observed by MIT assay in response to a treatment with PMA in the presence of (-)epigallocatechin gallate and quercetin. Western blot analysis and gelatin zymography revealed that exposure of HUVEC to PMA enhanced the levels and gelatinolytic activities of pro and active forms of MMP-2 and active form of MMP-9. (-)Epigallocatechin gallate attenuated PMA-stimulated secretion of active forms of MMP-2 and MMP-9 concomitantly with a loss of activities of these enzymes, which was related to the decreased mRNA levels of MMP. Quercetin was more potent than (-)epigallocatechin gallate in alleviating MMP-9 protein secretion and activity with a decrease in MMP-9 mRNA accumulation. Taken together, the results indicated that (-)epigallocatechin gallte and quercetin exhibited inhibitory effects on MMP activity and may qualify as chemopreventive and cardiovascular protective agents.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.4
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• pp.289-296
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• 2014

Human adipose-tissue-derived stromal cells (hADSCs) are abundant in adipose tissue and can differentiate into multi-lineage cell types, including adipocytes, osteoblasts, and chondrocytes. In order to define the optimal harvest site of adipose tissue harvest site, we solated hADSCs from different subcutaneous sites (upper abdomen, lower abdomen, and thigh) and compared their proliferation and potential to differentiate into adipocytes and osteoblasts. In addition, this study examined the effect of phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, on proliferation and differentiation of hADSCs to adipocytes or osteoblasts. hADSCs isolated from different subcutaneous depots have a similar growth rate. Fluorescence-activated cell sorting (FACS) analysis showed that the expression levels of CD73 and CD90 were similar between hADSCs from abdomen and thigh regions. However, the expression of CD105 was lower in hADSCs from the thigh than in those from the abdomen. Although the adipogenic differentiation potential of hADSCs from both tissue regions was similar, the osteogenic differentiation potential of hADSCs from the thigh was greater than that of hADSCs from the abdomen. Phorbol 12-myristate 13-acetate (PMA) treatment increased osteogenic differentiation and suppressed adipogenic differentiation of all hADSCs without affecting their growth rate and the treatment of Go6983, a general inhibitor of protein kinase C (PKC) blocked the PMA effect. These findings indicate that the thigh region might be a suitable source of hADSCs for bone regeneration and that the PKC signaling pathway may be involved in the adipogenic and osteogenic differentiation of hADSCs.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.428-433
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• 2015

Acetylshikonin, a natural naphthoquinone derivative compound, has been used for treatment of inflammation and cancer. In the present study, we have investigated whether acetylshikonin could regulate the NF-${\kappa}B$ signaling pathway, thereby leading to suppression of tumorigenesis. We observed that acetylshikonin significantly reduced proliferation of several cancer cell lines, including human pancreatic PANC-1 cancer cells. In addition, acetylshikonin inhibited phorbol 12-myristate 13-acetate (PMA) or tumor necrosis-${\alpha}$ (TNF-${\alpha}$)-induced NF-${\kappa}B$ reporter activity. Proteome cytokine array and real-time RT-PCR results illustrated that acetylshikonin inhibition of PMA-induced production of cytokines was mediated at the transcriptional level and it was associated with suppression of NF-${\kappa}B$ activity and matrix metalloprotenases. Finally, we observed that an exposure of acetylshikonin significantly inhibited the anchorage-independent growth of PANC-1 cells. Together, our results indicate that acetylshikonin could serve as a promising therapeutic agent for future treatment of pancreatic cancer.