• BMB Reports
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• v.56 no.6
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• pp.321-325
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• 2023

RNAs are pivotal molecules acting as messengers of genetic information and regulatory molecules for cellular development and survival. From birth to death, RNAs face constant cellular decision for the precise control of cellular function and activity. Most eukaryotic cells employ conserved machineries for RNA decay including RNA silencing and RNA quality control (RQC). In plants, RQC monitors endogenous RNAs and degrades aberrant and dysfunctional species, whereas RNA silencing promotes RNA degradation to repress the expression of selected endogenous RNAs or exogenous RNA derived from transgenes and virus. Interestingly, emerging evidences have indicated that RQC and RNA silencing interact with each by sharing target RNAs and regulatory components. Such interaction should be tightly organized for proper cellular survival. However, it is still elusive that how each machinery specifically recognizes target RNAs. In this review, we summarize recent advances on RNA silencing and RQC pathway and discuss potential mechanisms underlying the interaction between the two machineries.

• Molecules and Cells
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• v.25 no.1
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• pp.105-111
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• 2008

Radiotherapy is an important treatment for many malignant tumors, but there are recent reports that radiation may increase the malignancy of cancer cells by stimulating expression of type IV collagenases. In this study, we examined changes in matrix metalloproteinase (MMP) inhibitors, such as the tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2 and RECK, in response to irradiation in Panc-1 pancreatic cancer cells. Irradiation increased RECK protein levels but not mRNA levels, whereas no significant changes were found in TIMP-1 and TIMP-2. The enhanced RECK protein levels were associated with an increase in MMP inhibitory activity. However, irradiation slightly but reproducibly increased the invasiveness of the Panc-1 cells. Like irradiation, treatment of Panc-1 cells with transforming growth factor $(TGF)-{\beta}1$ led to a 2-fold increase in RECK protein levels. Transient transfection with Smad3 also increased RECK protein levels, but transfection with Smad7 markedly reduced them. Stable expression of Smad7 and treatment with SB431542, an inhibitor of $TGF-{\beta}$ receptor I kinase, abolished $TGF-{\beta}1$- and radiation-mediated effects on RECK. Furthermore, irradiation increased levels of phosphorylated Smad3. We conclude that radiation post-transciptionally enhances RECK protein levels in Panc-1 cells, at least in part, via $TGF-{\beta}$ signaling, and that irradiation increases Panc-1 invasiveness via a mechanism that may not be linked to MMP-2 activity.

• BMB Reports
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• v.30 no.6
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• pp.379-384
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• 1997

The effects of several ions on the specific activity and isozyme patterns of cellular and secretory isoperoxidases were studied in suspension-cultured cells of rice (Oryza sativa L.). Peroxidase release into the culture medium occurred in the absence of added calcium. The addition of calcium ion greatly stimulated the secretion of cationic isoperoxidases such as C2 and C3 into the medium: a maximum 11 fold increase of secretions occurred in the presence of 5 mM $CaCl_2$, and the secretion was accomplished within 1 hour after the addition of $CaCl_2$. About a 10 fold increase of the peroxidase secretion into the medium did occur with 0. 5% NaCl, whereas cellular isoperoxidase levels were reduced notably. About a 6 fold increase of the specific activity of cellular isoperoxidase was found in 5 mM $NiCl_2$-treated cell, while $NiCl_2$ had no effect on the secretion of peroxidase into the medium. Various concentrations of KCl did not change peroxidase secretion, but 5 mM $ZnCl_2$ reduced peroxidase secretion greatly. The major secretory isoperoxidases stimulated by $CaCl_2$, NaCl and cellulase were composed of cationic isoperoxidases C2 and C3, which were found to be localized in the cell wall of rice by examination of the enzyme in the protoplast. Furthermore, the secretion rates of secretory isoperoxidases were increased rapidly when cellulase was treated in the absence of the osmotic stabilizer of 0.4 M mannitol. These results suggest that the stimulations of secretory isoperoxidase levels seem to be due to the stimulation of secretion into the culture medium of rice.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.206-210
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• 2016

Background: Ionizing radiation causes cellular damage and death through the direct damage and/or indirectly the production of ROS, which induces oxidative stress. This study was designed to evaluate the in vivo radioprotective effects of a bio-active material coated fabric (BMCF) against ${\gamma}$-irradiation-induced cellular damage in Sprague-Dawley (SD) rats. Materials and Methods: Healthy male SD rats wore bio-active material coated (concentrations in 10% and 30%) fabric for 7 days after 3 Gy of ${\gamma}$-irradiation. Radioprotective effects were evaluated by performing various biochemical assays including spleen and thymus index, WBC count, hepatic damage marker enzymes [aspartate transaminase (AST) and alanine transaminase (ALT)] in plasma, liver antioxidant enzymes, and mitochondrial activity in muscle. Results and Discussions: Exposure to ${\gamma}$-irradiation resulted in hepatocellular and immune systemic damage. Gamma-irradiation induced decreases in antioxidant enzymes. However, wearing the BMCF-30% decreased significantly AST and ALT activities in plasma. Furthermore, wearing the BMCF-30% increased SOD (superoxide dismutase) and mitochondrial activity. Conclusion: These results suggest that wearing BMCF offers effective radioprotection against ${\gamma}$-irradiation-induced cellular damage in SD rats.

• Journal of Veterinary Clinics
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• v.34 no.1
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• pp.27-33
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• 2017

Although HDACIs affect ubiquitously expressed histone deacetylase and increase cellular senescence, there has been little study on the effect of age on treatment with HDACIs. Accordingly, the purpose of this study was to compare cellular senescence status and vorinostat-induced senescence in fibroblasts derived from aged dogs compared to young dogs. Skin tissues were taken from young (1-year-old) and aged (7-year-old) male dogs, and fibroblasts were cultured without (control) or with 10 uM of vorinostat for 24 hr. Beta-galactosidase activity was assessed, and real-time polymerase chain reaction and western blotting were performed to analyze the expression levels of transcripts and proteins related to cellular senescence. Beta-galactosidase activity was higher in aged dogs compared to young dogs in the control group, and was increased by vorinostat treatment. Expression of p21, p53 and p16 transcripts was higher in the aged than in the young group, and all transcripts were affected by vorinostat in both young and aged groups. Western blot results showed lower H3K9 acetylation in the aged dogs compared to the young dogs, and the acetylation was increased by vorinostat treatment in both groups. However, there was no significant difference between the transcript or protein alterations induced by vorinostat.

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

• Integrative Medicine Research
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• v.6 no.4
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• pp.395-403
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• 2017

Background: Gamisoyosan (GSS) is an herbal formula which has been used to treat women's diseases for several hundred years in Korea. GSS is one of the three most common prescriptions among women and is used to treat menopausal symptoms. Fatty liver disease is also common in postmenopausal women and can precede more severe diseases, such as steatohepatitis. The present study compared the effects of GSS on fatty liver using three different formulae, Dongui-Bogam (KIOM A), Korean Pharmacopeia (KIOM B) and Korean National Health Insurance (KIOM C). Methods: In oleic acid-induced HepG2 fatty liver cells, cellular lipid accumulation, triglycerides and total cholesterol were measured after treatment with three GSS formulae and simvastatin as a positive control. To investigate the phytoestrogen activity of GSS, MCF-7 cells were treated with GSS, and hormone levels were quantified. Also, qualitative analysis was performed with UPLC. Results: All types of GSS decreased cellular lipid accumulation. KIOM A was slightly less effective than the other two GSS formulae. KIOM B and KIOM C decreased cellular triglycerides more effective than simvastatin, but KIOM A did not affect cellular triglycerides. Cellular total cholesterol was decreased by all GSS and simvastatin. GSS showed phytoestrogen activity in MCF-7 cells. From the UPLC analysis data, geniposide, paeoniflorin and glycyrrhizin were detected form three GSS formulae. Conclusion: These results suggest that all GSS formulae have a beneficial effect on fatty liver disease during menopause and that differences of formula have no effect on the efficacy of the prescription.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.179-185
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• 2019

Background: Oxidative stress induces the production of reactive oxygen species (ROS), which play important causative roles in various pathological conditions. Black ginseng (BG), a type of steam-processed ginseng, has drawn significant attention due to its biological activity, and is more potent than white ginseng (WG) or red ginseng (RG). Methods: We evaluated the protective effects of BG extract (BGE) against oxidative stress-induced cellular damage, in comparison with WG extract (WGE) and RG extract (RGE) in a cell culture model. Ethanolic extracts of WG, RG, and BG were used to evaluate ginsenoside profiles, total polyphenols, flavonoid contents, and antioxidant activity. Using AML-12 cells treated with $H_2O_2$, the protective effects of WGE, RGE, and BGE on cellular redox status, DNA, protein, lipid damage, and apoptosis levels were investigated. Results: BGE exhibited significantly enhanced antioxidant potential, as well as total flavonoid and polyphenol contents. ATP levels were significantly higher in BGE-treated cells than in control; ROS generation and glutathione disulfide levels were lower but glutathione (GSH) and NADPH levels were higher in BGE-treated cells than in other groups. Pretreatment with BGE inhibited apoptosis and therefore protected cells from oxidative stress-induced cellular damage, probably through ROS scavenging. Conclusion: Collectively, our results demonstrate that BGE protects AML-12 cells from oxidative stress-induced cellular damages more effectively than WGE or RGE, through ROS scavenging, maintenance of redox status, and activation of the antioxidant defense system.

• Mycobiology
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• v.51 no.5
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• pp.372-378
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• 2023

Lkh1, a LAMMER kinase homolog in the fission yeast Schizosaccharomyces pombe, acts as a negative regulator of filamentous growth and flocculation. It is also involved in the response to oxidative stress. The lkh1-deletion mutant displays slower cell growth, shorter cell size, and abnormal DNA content compared to the wild type. These phenotypes suggest that Lkh1 controls cell size and cell cycle progression. When we performed microarray analysis using the lkh1-deletion mutant, we found that only four of the up-regulated genes in the lkh1-deletion were associated with the cell cycle. Interestingly, all of these genes are regulated by the Mlu1 cell cycle box binding factor (MBF), which is a transcription complex responsible for regulating the expression of cell cycle genes during the G1/S phase. Transcription analyses of the MBF-dependent cell-cycle genes, including negative feedback regulators, confirmed the up-regulation of these genes by the deletion of lkh1. Pull-down assay confirmed the interaction between Lkh1 and Yox1, which is a negative feedback regulator of MBF. This result supports the involvement of LAMMER kinase in cell cycle regulation by modulating MBF activity. In vitro kinase assay and NetPhosK 2.0 analysis with the Yox1T40,41A mutant allele revealed that T40 and T41 residues are the phosphorylation sites mediated by Lkh1. These sites affect the G1/S cell cycle progression of fission yeast by modulating the activity of the MBF complex.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.963-966
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• 2013