• Biomolecules & Therapeutics
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• v.31 no.3
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• pp.330-339
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• 2023

Liver kinase B1 (LKB1) is a crucial tumor suppressor involved in various cellular processes, including embryonic development, tumor initiation and progression, cell adhesion, apoptosis, and metabolism. However, the precise mechanisms underlying its functions remain elusive. In this study, we demonstrate that LKB1 interacts directly with malic enzyme 3 (ME3) through the N-terminus of the enzyme and identified the binding regions necessary for this interaction. The binding activity was confirmed to promote the expression of ME3 in an LKB1-dependent manner and was also shown to induce apoptosis activity. Furthermore, LKB1 and ME3 overexpression upregulated the expression of tumour suppressor proteins (p53 and p21) and downregulated the expression of antiapoptotic proteins (nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and B-cell lymphoma 2 (Bcl-2)). Additionally, LKB1 and ME3 enhanced the transcription of p21 and p53 and inhibited the transcription of NF-κB. Moreover, LKB1 and ME3 suppressed the phosphorylation of various components of the phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B signaling pathway. Overall, these results suggest that LKB1 promotes pro-apoptotic activities by inducing ME3 expression.

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.121-127
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• 1988

For selective purification of protein in Pleurotus cornucopiae (Per.) Rolland, affinity chromatography was performed by benzoyl-AH-Sepharose 4B gel synthesized using AH-Sepharose 4B with starting materials. Ligand capacity of benzoyl group was 9.3 micromole per milliliter of gel. Total apparent molecular weight of affinity protein was 255KD, which were protein complex of 29.5, 31.5 34.0, 71.0 and 89.0KD, respectively. The contents of nonpolar, polar, positively charged, and negatively charged amino acid were 45.68%, 26.93%, 11.81% and 15.58%, respectively. The nonpolar protein was selectively purified by hydrophobic ligand of benzoyl group of gel.

• Journal of Gastric Cancer
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• v.6 no.3
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• pp.181-188
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• 2006

Purpose: Heregulin is a natural ligand for erbB3 and erbB4. However, very little is known about their roles in the gastric cancer This retrospective study was performed to evaluate the frequencies of heregulin and erbB family protein expression and to compare their expressions with clinicopathologic parameters. Materials and Methods: Immunohistochemical expressions of heregulin and erbB family proteins were examined with tissue micro-array slides. A total of 251 gastric adenocarcinomas were classified as early cancers and advanced cancers and as having and not having lymph node metastases. Results: The positive rates of the heregulin, erbB1, erbB2, erbB3, and erbB4 protein stainings were 64%, 68%, 6%, 88%, and 76%, respectively. Intestinal type gastric adenocarcinomas showed higher expression of heregulin, erbB2, erbB3, and erbB4 proteins. Heregulin and erbB4 proteins showed lower expressions in advanced gastric carcinomas. However, erbB2 protein showed higher expression in advanced gastric carcinomas. The protein expressions of heregulin and erbB family proteins showed no relationship with survival rate. Co-expression groups of heregulin and erbB3 proteins or heregulin and erbB4 proteins showed higher expressions in intestinal type adenocarcinomas and early gastric carcinomas. Conclusion: Heregulin, erbB3, and erbB4 proteins may play a role in the early stage of adenocarcinomas.

• BMB Reports
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• v.42 no.3
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• pp.154-159
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• 2009

JARID1B (jumonji AT rich interactive domain 1B) is a large nuclear protein that is highly expressed in breast cancers and is proposed to function as a repressor of gene expression. In this paper, a phage display screen using the N-terminus of JARID1B as bait identified one of the JARID1B interacting proteins, namely PcG protein (Polycomb group) hPc2. We demonstrated that the C-terminal region, including the COOH box, was required for the interaction with the N-terminus of JARID1B. In a reporter assay system, co-expression of JARID1B with hPc2 significantly enhanced the transcriptional repression. These results support a role for hPc2 acting as a transcriptional co-repressor.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.231-237
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• 2017

This study was performed to cytotoxicity, tyrosinase inhibition activity, intracellular melanin contents to verify the whitening effect of fraction from Glycine soja Siebold et Zucc. (G. soja). Using western blotting, tyrosinase expression in B16F10 melanoma cells and expression levels of tyrosinase related protein-1 (TRP-1) and protein-2 (TRP-2) were examined. As a result, all of the fractions showed a high cell viability over 82% at the concentrations of 0.125, 0.25, 0.5, 2.0 mg/mL. When the whitening effects of fractions from G. soja were tested using B16F10 melanoma cells treated with the ${\alpha}$-melanocyte stimulating hormone (${\alpha}-MSH$), the EtOAc fractions inhibited tyrosinase and melanogenesis effectively. The result of protein expression measurement using western blot showed that TRP-1, TRP-2 and tyrosinase protein expression in B16F10 melanoma cells treated with extracts decreased. Therefore, it is concluded that the fractions from G. soja have whitening effect by inhibiting protein related melanogenesis.

• Nutrition Research and Practice
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• v.7 no.2
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• pp.89-95
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• 2013

Dietary inorganic sulfur is the minor component in our diet, but some studies suggested that inorganic sulfur is maybe effective to treat cancer related illness. Therefore, this study aims to examine the effects of inorganic sulfur on cell proliferation and gene expression in MDA-MB-231 human breast cancer cells. MDA-MB-231 cells were cultured the absence or presence of various concentrations (12.5, 25, or 50 ${\mu}mol/L$) of inorganic sulfur. Inorganic sulfur significantly decreased proliferation after 72 h of incubation (P < 0.05). The protein expression of $ErbB_2$ and its active form, $pErbB_2$, were significantly reduced at inorganic sulfur concentrations of 50 ${\mu}mol/L$ and greater than 25 ${\mu}mol/L$, respectively (P < 0.05). The mRNA expression of $ErbB_2$ was significantly reduced at an inorganic sulfur concentration of 50 ${\mu}mol/L$ (P < 0.05). The protein expression of $ErbB_3$ and its active form, $pErbB_3$, and the mRNA expression of $pErbB_3$ were significantly reduced at inorganic sulfur concentrations greater than 25 ${\mu}mol/L$ (P < 0.05). The protein and mRNA expression of Akt were significantly reduced at an inorganic sulfur concentration of 50 ${\mu}mol/L$ (P < 0.05), but pAkt was not affected by inorganic sulfur treatment. The protein and mRNA expression of Bax were significantly increased with the addition of inorganic sulfur concentration of 50 ${\mu}mol/L$ (P < 0.05). In conclusion, cell proliferation was suppressed by inorganic sulfur treatment through the ErbB-Akt pathway in MDA-MB-231 cells.

• The Plant Pathology Journal
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• v.39 no.6
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• pp.592-599
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• 2023

A defective RNA3 (D3Yα) of strain Y of cucumber mosaic virus (CMV-Y) was examined on host-specific maintenance, experimental conditions, and a viral factor required for its generation in plants. D3Yα was stably maintained in cucumber but not in tomato plants for 28 days post inoculation (dpi). D3Yα was generated in Nicotiana tabacum or N. benthamiana after prolonged infection in the second and the third passages, but not in plants of N. benthamiana grown at low temperature at 28 dpi or infected with CMV-Y mutant that had the 2b gene deleted. Collectively, we suggest that generation and retention of D3Yα depends on potential host plants and experimental conditions, and that the 2b protein has a role for facilitation of generation of D3Yα.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.236-244
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• 2006

This study was designed to determine the effects of daidzein (DE) on hepatic lipid metabolism in chicks fed with low protein (LP) diet based on casein. In experiment 1, the male chicks were fed with one of the three levels of dietary protein containing 10.95%, 21.9% and 43.8% protein content for 2 days. In experiment 2, the chicks were fed one of the three levels of protein with or without DE at 1,000 mg/kg diet for 2 days. Experiment 3 was conducted to compare DE (LP+DE) with estradiol (LP+E2) in chicks fed with LP diet for 7 days. Plasma lipid profiles, hepatic lipid profiles, activities of hepatic malic enzyme and isocitrate dehydrogenase (ICDH) were measured. Transcriptions of hepatic fatty acid synthase, apolipoprotein-B (APO-B), and fructose bisphosphatase mRNA were measured by RT-PCR. Increasing dietary protein levels markedly decreased the concentrations of plasma triglycerides, hepatic total lipids, hepatic TG, and the mRNA transcriptions while the increased dietary protein levels increased hepatic ICDH activities in experiment 1. In experiment 2, the effects of dietary protein levels on blood and hepatic lipid content were more prominent than those of the additional DE. Interestingly, plasma TG levels were affected by DE supplementation (p<0.05). In experiment 3, DE inhibited APO-B mRNA expressions and stimulated the accumulation of lipid in the liver through mechanisms different from E2. In this study, we demonstrate that DE has beneficial effects on blood lipid profiles, but that it inhibits APO-B mRNA transcription and aggravates the fatty liver induced by LP diet in chicks.

• YAKHAK HOEJI
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• v.47 no.1
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• pp.31-36
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• 2003

To investigate the effect of protein kinase on melanin production via cAMP-dependent pathway, we measured the melanin amount and tyrosinase activity in B16 melanoma cells stimulated by alpha-melanocyte stimulating hormone (MSH), forskolin and 8-Br-cAMP. MSH, forskolin and 8-Br-cAMP significantly increased both melanin production and tyrosinase activity in B16 cells. Melanin production and tyrosinase activity by MSH are significantly inhibited by cyclic AMP-dependent protein kinase inhibitor (KT5720) and protein kinase C down-regulation treated with PMA. Bisindolmaleimide (1$\mu$M), protein kinase C inhibitor, significantly inhibited melanin production and tyrosinase activity stimulated by MSH, forskolin and 8-Br-cAMP with the following order of potency: MSH＞forskolin＞8-Br-cAMP. Tyrosine kinase inhibitor, genistein and DHC, significantly inhibited both, but the inhibitory effect was more potent in 8-Br-cAMP-stimulated B16 cells than MSH-stimulated cells. NFkB inhibitor (parthenolide) significantly inhibited melanin production and tyrosinase activity. Neither melanin production nor tyrosinase activity induced by MSH, forskolin and 8-Br-cAMP were affected by KN-62 (calmodulin-dependent protein kinase II inhibitor), PD098059 (mitogen-activated protein kinase inhibitor, MAPKK) and worthmannin (phosphatidylinositol 3-kinase inhibitor). These results suggest that both protein kinase C and tyrosine kinase are involved in melanin production by cyclic AMP-dependent pathway and NFkB pathway may play an important role in cyclic AMP-dependent melanin production in B16 melanoma cells.

• Biomedical Science Letters
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• v.13 no.3
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• pp.213-221
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• 2007

This study was designed to investigate the correlation between the expression rate of p53 and p21 proteins, c-erbB-2 oncoprotein and $TGF-{\beta}1$ and tumor prognostic factors in colon cancer including the tumor size, histological differentiation and Dukes' stage. The expression rate of p53 protein was 11.4% (4 cases) at well differentiation, 48.6% (17 cases) at moderately differentiation, and 17.1% (6 cases) at poorly differentiation. In other words, the poorer differentiation, the higher the expression rate of p53 protein (P<0.05). The expression rate of p21 protein was 17.1% (6 cases) at well differentiation, 40.0% (14 cases) at moderately differentiation, and 8.6% (3 cases) at poorly differentiation, indicating that, as the histological malignant degeneration progressed, the expression rate of p21 protein decreased distinctively (P<0.05). However, the correlation of the above mentioned proteins with tumor size and Dukes' stage was not recognized. The expression rate of c-cerbB-2 oncoprotein was 11.4% (4 cases) at well differentiation, 54.3% (19 cases) at moderately differentiation, and 17.1% (6 cases) at poorly differentiation, indicating that the poorer differentiation, the higher expression rate of c-erbB-2 oncoprotein (P<0.05). The expression rate of $TGF-{\beta}1$ was 17.1% (6 cases) at well differentiation, 48.6% (17 cases) at moderately differentiation, and 11.4% (4 cases) at poorly differentiation. As Dukes' stage progressed, the expression rate of $TGF-{\beta}1$ was 8.6% (3 cases) in stage A, 20.0% (7 cases) in stage B, 37.1 % (13 cases) in stage C, and 11.4% (4 cases) in stage D. There was a difference in expression rates between Dukes' stages (P<0.05). In 10 cases, p53 protein was positive while p21 protein was negative, and in 6 cases, p53 protein was negative whereas p21 was positive (P<0.05). Therefore, a statistically significant inverse correlation between the expression rate of p53 protein and that of p21 protein was observed. In conclusion, since there was a signigicant correlation between histological differentiation of colon cancer and the expressions of p53 and p21 proteins and c-erbB-2 oncoprotein, and between Dukes' stage and the expression of $TGF-{\beta}1$, it was conformed that the overexpression of p53 and p21 proteins, c-erbB-2 oncoprotein, and $TGF-{\beta}1$ is closely associated with the occurrence of colon cancer and its progress. Accordingly, this study may be greatly beneficial to the presumption of diagnosis, treatment and prognosis of colon cancer patients.