• Polymer(Korea)
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• v.26 no.6
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• pp.710-717
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• 2002

Molecularly imprinted polymers were prepared in particle forms by crosslinking methacrylic acid (MAA)) using all trans-retinoic acid as a template. The HPLC column packed with the prepared molecular imprinted polymers showed high capability in separation of retinoid derivatives. The column capacity factor and selectivity increased with increasing MAA to template ratio when the incorporated template amount was fixed, as it statistically generated more binding sites between host molecules and template. Molecularly imprinted polymer particles prepared via an emulsion polymerization method were round-shaped and their sizes were more uniformly distributed, but their separation capability was inferior to those obtained by solution polymerization method. It was presumably because the loss of interaction strength between MAA and the template due to hydrogen bonding either between MAA and water or between template and water during the synthesis of molecularly imprinted polymers.

• BMB Reports
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• v.33 no.5
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• pp.402-406
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• 2000

In order to understand the role of AGP on the differentiation of promyelocytic leukemia cells, the AGP expression and its relation to cytokines were investigated during granulocytic or monocytic differentiation of HL-60 cells. When HL-60 cells were treated with all-trans-retinoic acid (ATRA) for 5 days, the cells were fully differentiated into granulocytes, and the AGP mRNA and protein levels were continuously increased up to 5 days in a dose- and time- dependent manner. However, in the case of the monocytic differentiation of HL-60 cells by tetradeanoyl phorbol acetate (TPA), the AGP gene expression was not induced. In addition, $IL-1{\alpha}$, $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ mRNAs were also enhanced during granulocytic differentiation. These cytokine transcripts showed a peak level 3 days after the ATRA treatment. It decreased gradually thereafter. However, direct addition of recombinant cytokines ($IL-1{\beta}$, IL-6 and $TNF-{\alpha}$) and dexamethasone to the HL-60 cell cultures showed no AGP induction. These findings suggest that the AGP and proinflammatory cytokines are expressed in ATRA-treated promyelocytic cells. However, these cytokines do not act as autocrine inducers on AGP expression. This fact implies that the AGP expression during granulocytic differentiation of HL-60 cells is induced through a signal pathway different from hepatocyte signaling in inflammation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.481-489
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• 2010

Introduction: TLR-5, a member of the toll-like receptor (TLR) family, is a element of the type I transmembrane receptors, which are characterized by an intracellular signaling domain homolog to the interleukin-1 receptor. These receptors recognize microbial components, particularly bacterial flagellin. All-trans retinoic acid (atRA, tretinoin), a natural metabolite of vitamin A, acts as a growth and differentiation factor in many tissues, and is also needed for immune functions. In this study, THP-1 human macrophage-monocytes were used to examine the mechanisms by which atRA regulated the expression of TLR-5. Because the molecular mechanism underlying this regulation at the transcriptional level is also unclear, this study examined which putative transcription factors are responsible for TLR-5 expression by atRA in immune cells. Materials and Methods: This study examined whether atRA induces the expression of TLR-5 in THP-1 cells using reverse transcription-polymerase chain reaction (RT-PCR), and which transcription factors are involved in regulating the TLR-5 promoter in RAW264.7 cells using a reporter assay system. Western blot analysis was used to determine which signal pathway is involved in the expression of TLR-5 in atRA-treated THP-1 cells. Results: atRA at a concentration of 10 nM greatly induced the expression of TLR-5 in THP-1 cells. Human TLR-5 promoter contains three Sp-1/GC binding sites around -50 bp and two NF-kB binding sites at -380 bp and -160 bp from the transcriptional start site of the TLR-5 gene. Sp-1/GC is primarily responsible for the constitutive TLR-5 expression, and may also contribute to NF-kB at -160 bp to induce TLR-5 after atRA stimulation in THP-1 cells. The role of NF-kB in TLR-5 expression was further confirmed by inhibitor pyrrolidine dithiocarbamate (PDTC) experiments, which greatly reduced the TLR-5 transcription by 70-80%. Conclusion: atRA induces the expression of the human TLR-5 gene and NF-kB is a critical transcription factor for the atRA-induced expression of TLR-5. Accordingly, it is conceivable that retinoids are required for adequate innate and adaptive immune responses to agents of infectious diseases. atRA and various synthetic retinoids have been used therapeutically in human diseases, such as leukemia and other cancers due to the antiproliferative and apoptosis inducing effects of retinoids. Therefore, understanding the molecular regulatory mechanism of TLR-5 may assist in the design of alternative strategies for the treatment of infectious diseases, leukemia and cancers.

• Tuberculosis and Respiratory Diseases
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• v.49 no.1
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• pp.93-98
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• 2000

Acute respiratory distress syndrome (ARDS) has been reported to be associated with a variety of medical and surgical conditions, including All-trans-retinoic acid (ATTA). ATRA is very efficaceous drug to acute promyelocytic leukemia (APL). This drug can induce complete remission at APL without fatal risk of disseminated intravascular coagulation. But ATRA treatment, sometimes, produces the symptoms of fever, weight gain and acute respiratory distress, renal function impairment. The causes of these symptoms are not fully proved, but supposed as the result of leukostasis and capillary leak syndrome from excessive leukocyte differentiation and cytokines release. Recently, we experienced a 24-year-old woman who complained gum bleeding for 6 days. At bone marrow biopsy, she was diagnosed as APL. 2 days after ATRA treatment, she was suffered from the symptoms of dyspnea and general ache. At laboratory examination, total leukocyte count was 50,400/$mm^3$, $PaO_2$ was 42.5 mm Hg and chest PA revealed the findings compatible with ARDS. Treatment with low dose ara-C, corticosteroid and general supportive cares were tried. Within 3 days after treatment, the patient recovered from ARDS by evidence of arterial blood gas study and chest radiographs. She has acquired complete remission of APL with maintenance of A TRA. And so, we present this case with a review of related literatures.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.298-304
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• 1998

Retinoids are applied to not only cancer prevention but also cancer chemotherapy by stimulating differentiation of cells. We studied differentiation inducing effect of all-trans retinoic acid (ATRA) by studying proportion of high dense fractions of stem-like cells and the size of S phase fraction in cell cycle. From mammary organoids obtained from 7- to 8-week old F344 female rat mammary gland, we cultured rat mammary epithelial cells (RMEC) and treated physiological doses of $10^{-6}$, $10^{-7}$, and $10^{-8}$ M ATRA from the first day and then cultured for 4, 7, and 14 days. After that, immunostaining was performed using peanut agglutinin (PNA) and anti-Thy-1.1 monoclonal antibody (Thy-1.1) that can be used as markers of differentiation. We separated four different cell subpopulations by flow cytometry: cells negative to both reagents (B-), PNA-positive cells (PNA+), Thy-1.1-positive cells (Thy-1.1+), and cells positive to both reagents (B+). We observed continuous decreases of high dense fractions of stem-like cells (PNA+ subpopulations) for 14 days and as much decreases as high doses of ATRA, which were thought to be proportional to doses of ATRA. We labeled RMEC with bromodeoxyuridine and investigated cell cycle fractions that went through S phase. We observed a tendency of decrease of S phase fraction with time in culture, which, is thought to be related to continuous decreases of PNA+ subpopulations and inhibitory role of ATRA on cell cycle. These results suggest that physiological doses of ATRA could stimulate differentiation of RMEC and convert stem-like RMEC to differentiated cells in SFM for a relatively long period of 14 days.

• Korean Journal of Veterinary Research
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• v.46 no.2
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• pp.97-105
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• 2006

All-trans retinoic acid (AtRA) induces growth inhibition and apoptosis in a variety of tumer cells, including MCF-7 cells. Insulin-like growth factors (IGFs) system has been reported to be associated with the development of cancer. Although MCF-7 cell with AtRA is to be the major stimulus for the cell growth and apoptosis, the mechanism of insulin-like growth factor-I (IGF-I)/insulin-like growth factor binding protein-3 (IGFBP-3) system remains to be elucidated. Thus, this study was conducted to the effect of AtRA on the gene expression and level of IGF-I and IGFBP-3. In addition, we investigated the involvement of PKC-${\delta}$ on the IGF-I and IGFBP-3 secretion in MCF-7 cell. AtRA(${\geq}10^{-7}M$) decreased the IGF-1 secretion and mRNA expressions, but increased IGFBP-3 secretion and mRNA expressions in MCF-7 cells. Especially, the treatment of AtRA at 72 hours caused a significant reduction in the IGF-I secretion and mRNA expressions but increment in IGFBP-3 secretion and mRNA expressions (p < 0.05). $10^{-7}M$ AtRA activated PKC-${\delta}$ that is one among PKC-$\iota$, ${\alpha}$, ${\lambda}$ and ${\delta}$ in MCF-7 cell. Rotllerin, a PKC-${\delta}$ inhibitor, blocked AtRA-induced inhibition of the IGF-I and mRNA expressions, and increase of lGFBP-3 and mRNA expressions in MCF-7 cell. Together, AtRA inhibited the IGF-I secretion and mRNA expressions, but increased IGFBP-3 secretion and mRNA expressions in MCF-7 cell. Furthermore, AtRA-induced alteration of IGF-I, IGFBP-3 secretion, and the gene expressions were mediated via PKC-${\delta}$ activity.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.286-292
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• 2012

All-trans retinoic acid (ATRA) is currently used in adjuvant differentiation-based treatment of residual or relapsed neuroblastoma (NB). It has been reported that short-term ATRA treatment induces migration and invasion of SH-SY5Y via transglutaminase-2 (Tgase-2). However, the detailed mechanism of Tgase-2's involvement in NB cell invasion remains unclear. Therefore we investigated the role of Tgase-2 in invasion of NB cells using SH-SY5Y cells. ATRA dose-dependently induced the invasion of SH-SY5Y cells. Cystamine (CTM), a well known tgase inhibitor suppressed the ATRA-induced invasion of SH-SY5Y cells in a dose-dependent manner. Matrix metalloproteinase -9 (MMP-9) and MMP-2, well known genes involved in invasion of cancer cells were induced in the ATRA-induced invasion of the SH-SH5Y cells. Treatment of CTM suppressed the MMP-9 and MMP-2 enzyme activities in the ATRA-induced invasion of the SH-SY5Y cells. To confirm the involvement of Tgase-2, gene silencing of Tgase-2 was performed in the ATRA-induced invasion of the SH-SH5Y cells. The siRNA of Tgase-2 suppressed the MMP-9 and MMP-2 activity of the SH-SY5Y cells. MMP-2 and MMP-9 are well known target genes of NF-${\kappa}B$. Therefore the relationship of Tgase-2 and NF-${\kappa}B$ in the ATRA-induced invasion of the SH-SY5Y cells was examined using siRNA and CTM. ATRA induced the activation of NF-${\kappa}B$ in the SH-SY5Y cells and CTM suppressed the activation of NF-${\kappa}B$. Gene silencing of Tgase-2 suppressed the MMP expression by ATRA. These results suggested that Tgase-2 might be a new target for controlling the ATRA-induced invasion of NBs.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.234-238
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• 2000

The cleavage products formed by autoxidation of phytofluene were evaluated in order to elucidate possible oxidation products of phytofluene under oxidative conditions. Phytofluene solubilized at 50$\mu$M in liposomal suspension was oxidized by incubating at 37$^{\circ}C$ for 72 h. Among a number of oxidation products formed, five products in the carbonyl compound fraction were identified as 6, 10, 14-trimethylpentadeca-3,5,9,13-tetraen-2-one, phytapentaenal, 5,9,13,17-tetramethyloctadeca-2,4,6,8,12,16-hexaenal, 5,9,13,17-tetramethyloctadeca-2,4,8,12,16-pentaenal, 2,7,11,15,19-pentamethylicosa-2,4,6,10,14,18-hexaenal and 4,9,13,17,21-pentamethyldocosa-2,4,6,8,12,16,20-heptaenal. These correspond to a series of products formed by cleavage in the respective eight conjugated double bonds of phytofluene. Also, 4,5-didehydorgeranyl geranoic acid was formed by autoxidation of phytofluene in liposomal suspension. The pig liver homogenate had the ability to convert phytapentaenal to 4,5-didehydrogeranyl geranoic acid, comparable to the conversion of all-trans-retinal to all-trans-retinoic acid. These results suggest that phytofluene is cleaved to a series of long-chain and short-chain carbonyl compounds under the oxidative condition in vitro and that phytapentaenal is further enzymatically converted to 4,5-didehydrogeranyl geranoic acid.

• International Journal of Oral Biology
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• v.37 no.3
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• pp.115-120
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• 2012

Retinoic acid plays an important role in the regulation of cell growth and differentiation. In our present study, we evaluated the effects of all-trans retinoic acid (RA) on cell proliferation and on the cell cycle regulation of human gingival fibroblasts (HGFs). Cell proliferation was assessed using the MTT assay. Cell cycle analysis was performed by flow cytometry, and cell cycle regulatory proteins were determined by western blot. Cell proliferation was increased in the presence of a 0.1 nM to 1 ${\mu}M$ RA dose range, and maximal growth stimulation was observed in cells exposed to 1 nM of RA. Exposure of HGFs to 1 nM of RA resulted in an augmented cell cycle progression. To elucidate the molecular mechanisms underlying cell cycle regulation by RA, we measured the intracellular levels of major cell cycle regulatory proteins. The levels of cyclin E and cyclin-dependent kinase (CDK) 2 were found to be increased in HGFs following 1 nM of RA treatment. However, the levels of cyclin D, CDK 4, and CDK 6 were unchanged under these conditions. Also after exposure to 1 nM of RA, the protein levels of $p21^{WAF1/CIP1}$ and $p16^{INK4A}$ were decreased in HGFs compared with the control group, but the levels of p53 and pRb were similar between treated and untreated cells. These results suggest that RA increases cell proliferation and cell cycle progression in HGFs via increased cellular levels of cyclin E and CDK 2, and decreased cellular levels of $p21^{WAF1/CIP1}$ and $p16^{INK4A}$.

• Food Science and Biotechnology
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• v.14 no.3
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• pp.424-427
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• 2005

The cleavage products formed by the autoxidation of phytofluene were evaluated in order to elucidate possible oxidation products of phytofluene in the oxidative condition. Among a number of oxidation products formed, the following five in the carbonyl compound fraction were identified: 6, 10, 14-trimethylpentadeca-3,5,9,13-tetraen-2-one, phytapentaenal, 5,9,13,17-tetramethyloctadeca-2,4,6,8,12,16-hexaenal, 5,9,13,17-tetramethyloctadeca-2,4,8,12, 16-pentaenal, 2,7,11,15,19-pentamethylicosa-2,4,6,10,14,18-hexaenal and 4,9,13,17,21-pentamethyldocosa-2,4,6,8,12,16,20-heptaenal. In addition, 4,5-didehydrogeranyl geranoic acid was formed by the autoxidation of phytofluene in liposomal suspension. The pig liver homogenate was able to convert phytapentaenal to 4,5-didehydrogeranyl geranoic acid, in a manner comparable to the conversion of all-trans-retinal to all-trans-retinoic acid. These results suggest firstly that phytofluene is cleaved into a series of long-chain and short-chain carbonyl compounds under the oxidative condition in vitro and secondly that phytapentaenal is further enzymatically converted to 4,5-didehydrogeranyl geranoic acid.