• Journal of Life Science
• /
• v.26 no.1
• /
• pp.140-145
• /
• 2016

Genes in multicellular organisms are transcribed in development, differentiation, or tissue-specific manners. The transcription of genes is activated by enhancers, which are transcription regulatory elements located at long distances from the genes. Recent studies have reported that noncoding RNAs are transcribed from active enhancers by RNA polymerase II (RNA Pol II); these are called enhancer RNAs (eRNAs). eRNAs are transcribed bi-directionally from the enhancer core, and are capped on the 5’ end but not spliced or polyadenylated on the 3’ end. The transcription of eRNAs requires the binding of transcription activators on the enhancer and associates positively with the transcription of the target gene. The transcriptional inhibition of eRNAs or the removal of eRNA transcripts results in the transcriptional repression of the coding gene. The transcriptional procedure of eRNAs causes enhancer- specific histone modifications, such as histone H3K4me1/2. eRNA transcripts directly interact with Mediator and Rad21, a cohesin subunit, generating a chromatin loop structure between the enhancer and the promoter of the target gene. The recruitment of RNA Pol II into the promoter and its elongation through the coding region are facilitated by eRNAs. Here, we will review the features of eRNAs, and discuss the mechanism of eRNA transcription and the roles of eRNAs in the transcriptional activation of target genes.

• Molecules and Cells
• /
• v.43 no.2
• /
• pp.198-202
• /
• 2020

Comprehensive inhibition of RUNX1, RUNX2, and RUNX3 led to marked cell suppression compared with inhibition of RUNX1 alone, clarifying that the RUNX family members are important for proliferation and maintenance of diverse cancers, and "cluster regulation of RUNX (CROX)" is a very effective strategy to suppress cancer cells. Recent studies reported by us and other groups suggested that wild-type RUNX1 is needed for survival and proliferation of certain types of leukemia, lung cancer, gastric cancer, etc. and for their one of metastatic target sites such as born marrow endothelial niche, suggesting that RUNX1 often functions oncogenic manners in cancer cells. In this review, we describe the significance and paradoxical requirement of RUNX1 tumor suppressor in leukemia and even solid cancers based on recent our findings such as "genetic compensation of RUNX family transcription factors (the compensation mechanism for the total level of RUNX family protein expression)", "RUNX1 inhibition-induced inhibitory effects on leukemia cells and on solid cancers through p53 activation", and "autonomous feedback loop of RUNX1-p53-CBFB in acute myeloid leukemia cells". Taken together, these findings identify a crucial role for the RUNX cluster in the maintenance and progression of cancers and suggest that modulation of the RUNX cluster using the pyrrole-imidazole polyamide gene-switch technology is a potential novel therapeutic approach to control cancers.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.21 no.1
• /
• pp.243-249
• /
• 2007

The French paradox has been attributed to the antioxidant properties of flavonoids present in the red wine. Amentoflavone(AF) is a bi-flavonoid compound with anti-fungal and anti-inflammatory activities. We isolated AF from Selaginella tamariscina, and studied its effects on nuclear factor-B(NF-B)-mediated MMP-9 gene expression in RAW264.7 cells. AF blocked the lipopolysaccharide(LPS)-induced expression of MMP-9. Zymographic and immunoblot analyses showed that AF suppressed LPS-induced MMP-9 expression in a dose-dependent manner. To clarify the mechanistic basis for its inhibition of MMP-9 induction, we examined the effect of AF on the transactivation of MMP-9 gene by luciferase reporter activity using -1.59 kb flanking region. AF potently suppressed the reporter gene activity. This inhibition was characterized by down-regulation of MMP-9, which was transcriptionally regulated at NF-B site and activation protein-1 (AP-1) site in the MMP-9 promoter, two important nuclear transcription factors that are involved in MMP-9 expression. These findings indicate the efficacy of AF in inhibiting MMP-9 expression through the transcription factors NF-B and AP-1 on LPS-induced RAW264.7 cells.

• Journal of Ginseng Research
• /
• v.39 no.3
• /
• pp.238-242
• /
• 2015

Background: Panax ginseng has been used to prolong longevity and is believed to be useful for improving skin complexion. Ginsenosides are the most active components isolated from ginseng, and ginsenoside Rg3 (G-Rg3) in particular has been demonstrated to possess antioxidative, antitumorigenic, and anti-inflammatory properties. The aim of this study was to examine the ability of G-Rg3 to inhibit melanogenesis. Methods: The effects of G-Rg3 on melanin contents and the protein levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related protein 1 (TRP1) were evaluated. Melanogenesis-regulating signaling molecules such as Akt and extracellular signal-regulated kinase (ERK) were also examined to explore G-Rg3-induced antimelanogenic mechanisms. Results: G-Rg3 was found to significantly inhibit the synthesis of melanin in normal human epidermal melanocytes and B16F10 cells in a dose-dependent manner. The activity of cellular tyrosinase and the expression of MITF, tyrosinase, and TRP1 were all reduced, whereas ERK was strongly activated. PD98059 (a specific inhibitor of ERK) attenuated the G-Rg3-induced inhibition of melanin synthesis and tyrosinase activity. Conclusion: Taken together, these results showed that G-Rg3 induces the activation of ERK, which accounts for its antimelanogenic effects. G-Rg3 may be a promising safe skin-whitening agent, adding to the long list of uses of P. ginseng for the enhancement of skin beauty.

• The Korea Journal of Herbology
• /
• v.30 no.4
• /
• pp.95-100
• /
• 2015

Objectives : The purpose of this study was to research the whitening effects and developing by cosmetics of the extract fromDioscoreae Rhizoma, which is one of the most popular health-promoting herb in herbal medications.Methods : We performed tyrosinase inhibition assay, reverse transcription-polymerase chain reaction (RT-PCR) and western blot for whitening effects. Also we measured MTT assay for cell viability.Results : The results were obtained as follows : For whitening effect, tyrosinase inhibition rate of extract fromDioscoreae Rhizomashowed more than 42.28% at 1,000 ㎍/㎖ concentration. Cell toxicity effect on melanoma cells (B16F10) of extract fromDioscoreae Rhizomashowed 81.97% with toxicity at 50 ㎍/㎖ concentration. So we were measured at a concentrations of 5, 10 and 50 ㎍/㎖ in all experiments involving cell. In addition, whitening related mRNAs including microphthalmia associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), tyrosinase were reduced byDioscoreae Rhizoma. We also foundDioscoreae Rhizomatransiently decreased protein kinase A (PKA) which is known to be upstream to the down regulation of MITF and tyrosinase. But phosphorylation of extracellular signal related kinase (pERK) were increased byDioscoreae Rhizoma. These results imply thatDioscoreae Rhizomadecrease melanogenesis via ERK activation and subsequent down regulation of MITF and tyrosinase.Conclusions : Therefore, all these findings suggested the potent usage ofDioscoreae Rhizomaas materials of functional cosmetics by confirming whitening activity related with melanin content.

• Journal of Marine Bioscience and Biotechnology
• /
• v.13 no.1
• /
• pp.1-9
• /
• 2021

Codium fragile (Suringar) Hariot, a green alga of the Codiales family, has been reported to have several bioactive properties, including antioxidant and anti-inflammatory properties. However, its antiobesity and whitening effects and their underlying mechanisms are unclear. This study aimed to evaluate the antiobesity and melanogenesis inhibitory effects of C. fragile using methanol extracts of C. fragile (MECF). The results of this study revealed that MECF inhibited the accumulation of lipid droplets and triacylglycerol in differentiated 3T3-L1 adipocytes, which was associated with the inhibition of the expression of adipogenesis-related transcription factors, such as peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein-α (C/EBPα), and C/EBPβ, which function as the key regulators of adipogenesis. Also, MECF reduced tyrosinase activity and melanin content in B16F10 cells as well as the expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-related transcription factor in the presence of α-melanocyte-stimulating hormone. Taken together, our findings suggest that the extract of C. fragile could be considered a promising functional ingredient for the prevention and treatment of obesity and skin pigmentation in the food and cosmetic industry.

• Molecules and Cells
• /
• v.28 no.5
• /
• pp.489-494
• /
• 2009

We have previously shown that the down-regulation of protein kinase CKII activity is tightly associated with cellular senescence of human fibroblast IMR-90 cells. Here, we examined the roles of p53 and $p21^{Cip1/WAF1}$ in senescence development induced by CKII inhibition using wild-type, isogenic p53-/- and isogenic p21-/- HCT116 human colon cancer cell lines. A senescent marker appeared after staining for senescence-associated ${\beta}$-galactosidase activity in wild-type HCT116 cells treated with CKII inhibitor or $CKII{\alpha}$ siRNA, but this response was almost abolished in p53- or $p21^{Cip1/WAF1}$-null cells. Increased cellular levels of p53 and $p21^{Cip1/WAF1}$ protein occurred with the inhibition of CKII. CKII inhibition upregulated p53 and $p21^{Cip1/WAF1}$ expression at post-transcriptional level and transcription level, respectively. RB phosphorylation significantly decreased in cells treated with CKII inhibitor. Taken together, this study shows that the activation of the $p53-p21^{Cip1/WAF1}$ pathway acts as a major mediator of cellular senescence induced by CKII inhibition.

• Journal of Life Science
• /
• v.23 no.10
• /
• pp.1216-1222
• /
• 2013

NK cells are lymphoid immune cells that participate in innate immunity to protect against foreign pathogens and transforming cells. It is known that the activity of NK cells is regulated by a balance between activating and inhibitory signals rather than specific antigens. One important activating signal is mediated by the NKG2D receptor, which recognizes NKG2D ligands on cancer cells. Therefore, tumor cells that express sufficient amounts of NKG2D ligands could be eliminated by NKD2D+ cells, including NK cells. Oncogenes drive tumor cells to apoptosis resistant and uncontrolled proliferation by altered expression of many critical genes. Therefore, the expression of NKG2D ligands may be affected by oncogenes. This study focused on increasing the susceptibility of cancer cells to NK cells by regulating the expression of NKG2D ligands influenced by three oncogenes: k-ras, wnt, and c-myc. We demonstrated that inhibition of k-ras and c-myc increased the expression of NKG2D ligands and enhanced the susceptibility of cancer cells to NK cells. On the contrary, inhibition of the wnt pathway decreased MICA and ULBP1 transcripts. Although the decreased transcription of NKG2D ligands by inhibition of the wnt pathway, surface proteins of NKG2D ligands were not changed, and the susceptibility of HCT-116 cells was unaffected. The results demonstrate that the transcription of NKG2D ligands are regulated deferentially by the k-ras, c-myc, and wnt pathways and that the cytotoxicity of NK cells solely depends on the amount of surface NKG2D ligands.

• Journal of Life Science
• /
• v.29 no.4
• /
• pp.447-454
• /
• 2019

Fat accumulation in adipocytes occurs through the process of adipogenesis in which preadipocytes differentiate into adipocytes. Obesity is a metabolic disorder caused by excessive accumulation of fat in the body, which increases the incidence of cardiovascular diseases, hypertension, type 2 diabetes, hyperlipidemia, and various cancers. Recently, inhibition of adipocyte differentiation was shown to be a potential antiobesity strategy. In this study, the inhibitory effect of dichloromethane fractions from Illicium verum Hooker fil. water extract on the differentiation of 3T3-L1 preadipocytes to adipocytes was investigated. Dichloromethane fractions from I. verum Hooker fil. significantly inhibited adipocyte differentiation when applied during the adipocyte differentiation process, as assessed by measuring fat accumulation using Oil-red O staining. In addition, dichloromethane fractions from I. verum Hooker fil. reduced important adipogenic transcription factors, such as CCAAT/enhancer binding protein ${\alpha}$ ($C/EBP{\alpha}$), $C/EBP{\beta}$, and peroxisome proliferator activated receptor ${\gamma}$ ($PPAR{\gamma}$). The expression of FAS and LPL, which are terminal differentiation markers of mature adipocytes, was also reduced in the 3T3-L1 adipocytes treated with dichloromethane fractions from I. verum Hooker fil. In addition, the treatment significantly inhibited mitotic clonal expansion, which is essential for adipocyte differentiation, by arresting the G1 phase of the cell cycle. Taken together, these results suggest that dichloromethane fractions from I. verum Hooker fil. may be a natural material with antiobesity effects.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2023.04a
• /
• pp.51-51
• /
• 2023

The world-wide rate of obesity is increasing continuously, representing a serious medical threat since it is associated with a variety of diseases including type 2 diabetes, cardiovascular disease, and numerous cancers. Sophora japonicais used as a traditional herb for medicinal purposes in eastern Asia. However, the anti-obesity effects of S. japonicafruit have not been explored. The aim of this study is to investigate the inhibition of adipocyte differentiation and adipogenesis by an ethanol extract of S. japonicafruit (EESF) in 3T3-L1 pre-adipocytes. Our results demonstrate that EESF suppressed the terminal differentiation of 3T3-L1 pre-adipocytes in a dose-dependent manner, as confirmed by a decrease in lipid droplet number and lipid content through Oil Red O staining. EESF significantly reduced the accumulation of cellular triglyceride, which was associated with a significant inhibition of the levels of pro-adipogenic transcription factors, including PPARγ, C/EBPα and C/EBPβ. In addition, EESF potentially down regulated the expression levels of adipocyte-specific proteins, including aP2 and leptin. In particular, EESF treatment effectively enhanced the activation of the AMPK signaling pathway; however, the co-treatment with compound C, an inhibitor of AMPK, significantly restored the EESF-induced inhibition of pro-adipogenic transcription factors and adipocyte-specific genes. These results indicate that EESF may exert an anti-obesity effect by controlling the AMPK signaling pathway, suggesting that the fruit extract of S. japonica may be a potential anti-obesity agent.