• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.143-148
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• 2008

Caveolin-1 (CAV1) is an integral membrane protein that may function as a scaffold for plasma membrane proteins and acts as a tumor suppressor protein. One causative factor of chemotherapy-resistant cancers is P-plycoprotein (P-gp), the product of the multidrug resistance-1 gene (MDR1), which is localized in the caveolar structure. Currently, the interactive roles of CAV1 and MDR1 expression in the death of cancer cells remain controversial. In this study, we investigated the effects of indomethacin on the cell viability and the expression levels of MDR1 mRNA and protein in a CAV1-siRNA-mediated gene knockdown hepatoma cell line (SK-Hep1). Cell viability was significantly decreased in CAV1-siRNA-transfected cells compared with that of control-siRNA-transfected cells. Furthermore, the viability of cells pretreated with CAV1 siRNA was markedly decreased by treatment with indomethacin (400${\mu}$M for 24 h). However, the protein and mRNA levels of MDR1 were unchanged in CAV1-siRNA-transfected cells. These results suggest that CAV1 plays an important role as a major survival enzyme in cancer cells, and indomethacin can sensitively induce cell death under conditions of reduced CAV1 expression, independent of MDR1 expression.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.311-319
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• 2023

Caveolin-1 (Cav-1) is the main structural component of the caveolae on the plasma membrane, which regulates various cellular processes, including cell growth, differentiation, and endocytosis. Although a recent study demonstrated that Cav-1 might be involved in diabetes-associated inflammation, its exact role in the intestine was unclear. In this study, we examined the intestinal expression of Cav-1 in diabetic conditions. We also investigated its effect on lipopolysaccharide (LPS)-induced inflammation by expressing this protein in human intestinal Caco-2 cells lacking Cav-1. We observed that increased Cav-1 levels and decreased expression of tight junction proteins affected intestinal permeability in high-fat diet-induced diabetic mice. When Caco-2 cells were treated with LPS, Cav-1 enhanced the NF-κB signaling. Moreover, LPS reduced the expression of tight junction proteins while it increased cell-cell permeability and reactive oxygen species generation in Caco-2 cells and this effect was amplified by cav-1 overexpression. LPS treatment promoted phosphorylation of tyrosine-14 (Y14) on Cav-1, and the LPS-induced NF-κB signaling was suppressed in cells expressing non-phosphorylatable Cav-1 (tyrosine-14 to phenylalanine mutant), which reduced intestinal barrier permeability. These results suggest that Cav-1 expression promotes LPS-induced inflammation in Caco-2 cells, and phosphorylation of Y14 on Cav-1 might contribute to the anti-inflammatory response in LPS-induced NF-κB signaling and cell permeability.

• Molecules and Cells
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• v.45 no.12
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• pp.950-962
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• 2022

Aging is a major risk factor for common neurodegenerative diseases. Although multiple molecular, cellular, structural, and functional changes occur in the brain during aging, the involvement of caveolin-2 (Cav-2) in brain ageing remains unknown. We investigated Cav-2 expression in brains of aged mice and its effects on endothelial cells. The human umbilical vein endothelial cells (HUVECs) showed decreased THP-1 adhesion and infiltration when treated with Cav-2 siRNA compared to control siRNA. In contrast, Cav-2 overexpression increased THP-1 adhesion and infiltration in HUVECs. Increased expression of Cav-2 and iba-1 was observed in brains of old mice. Moreover, there were fewer iba-1-positive cells in the brains of aged Cav-2 knockout (KO) mice than of wild-type aged mice. The levels of several chemokines were higher in brains of aged wild-type mice than in young wild-type mice; moreover, chemokine levels were significantly lower in brains of young mice as well as aged Cav-2 KO mice than in their wild-type counterparts. Expression of PECAM1 and VE-cadherin proteins increased in brains of old wild-type mice but was barely detected in brains of young wild-type and Cav-2 KO mice. Collectively, our results suggest that Cav-2 expression increases in the endothelial cells of aged brain, and promotes leukocyte infiltration and age-associated neuroinflammation.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8367-8370
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• 2014

The relationship between caveolin-1 (Cav-1) and clinicopathological characteristics of gastric cancer is controversial, although Cav-1 plays an important role in tumor metastasis. To evaluate the clinicopathological and prognostic value of expression in patients with gastric cancer, a meta-analysis was performed to investigate the impact on clinicopathological parameters and prognosis in gastric cancer cases. Studies assessing these parameters for Cav-1 in gastric cancer were identified up to June 2014. Finally, a total of six studies met the inclusion criteria. Our combined results showed that Cav-1 expression was significantly associated with the Lauren classification (pooled OR=0.603, 95% CI: 0.381-0.953, P=0.030). Furthermore, we found that Cav-1 expression predicted a better overall survival in gastric cancer patients (pooled OR=0.590, 95% CI: 0.360-0.970, P=0.038, fixed-effect). In conclusion, the overall data of the present meta analysis showed that Cav-1 expression was not correlated with clinicopathological features except for the Lauren classification. Simultaneously, Cav-1 overexpression predicted a better overall survival in gastric cancer. Cav-1 expression in tumors is a candidate positive prognostic biomarker for gastric cancer patients.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.538-544
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• 2008

Activated protein C (APC) is thought to exert antiinflammatory activities through the endothelial protein C receptor (EPCR)-dependent cleavage of protease activated receptor 1 (PAR-1) in endothelial cells. Since thrombin cleaves PAR-1 with $\sim$3-4-orders of magnitude higher efficiency, and PAR-1 is a target for proinflammatory activities of thrombin, it is not understood how APC can elicit protective responses through the cleavage of PAR-1. In this study, we demonstrate that EPCR is associated with caveolin-1 in endothelial lipid rafts, but its occupancy by protein C leads to its dissociation from caveolin-1 and subsequent recruitment of PAR-1 to protective signaling pathways through the coupling of PAR-1 to Gi-protein. When EPCR is bound by protein C, the PAR-1-dependent protective response in endothelial cells can be mediated by either thrombin or APC. These results provide a new paradigm for understanding the mechanism through which PAR-1 and EPCR participate in cellular signaling events in endothelial cells.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2295-2299
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• 2013

Background: To explore the role of caveolin-1(CAV-1) gene silencing on MAPK activation in lipopolysaccharide (LPS)-challenged human mammary epithelial cells. Methods: We established a MCF-10ACE of CAV-1 gene silencing from human mammary epithelial cell line MCF-10A by RNAi technology. DNA Microarray were used to detect the expression of inflammation-associated genes in MCF10ACE. Western blotting was used to examine the activation of MAPK in lipopolysaccharide(LPS)-challenged MCF-10A and MCF-10ACE. Moreover, immunofluorescence and Western bloting were performed to detect the co-localization of CAV-1 and toll-like receptor 4 (TLR4) in human mammary epithelial cells. Results: MCF-10ACE exhibited significant increases in inflammation-associated gene expression, especially IL-6 (~7-fold) and IL6R (~17-fold). In addition, LPS-induced p38 MAPK and JNK MAPK activation was significantly increased in MCF-10ACE. Furthermore, CAV-1 co-localized with TLR4 and appeared a negative correlation trend. Conclusion: CAV-1 gene silencing promotes MAPK activation via TLR4 signaling in human mammary epithelial cells response to LPS.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.145-154
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• 2011

By a series of positional cloning, we successfully narrowed down the AM candidate region to approximately 1.2 Mbp on GGA2q including 7 functional genes. Subsequently, we identified WWP1 gene as the most likely AM candidate by sequence comparison. The amino acid sequence around the candidate mutation was highly conserved among tetrapods, suggesting that WWP1 is the causative gene of chicken muscular dystrophy. Transfection of mutated WWP1 gene into $C_2C_{12}$ myoblasts disrupted muscle differentiation process. The abnormal muscle differentiation is a characteristic of chicken muscular dystrophy, so we could demonstrate a part of phenotype of the disease. Furthermore, western blotting revealed that accumulation of caveolin-3 protein is limited in damaged muscle of muscular dystrophic chicken, suggesting caveolin-3 may be associated with the pathological change of the disease. We could conclude that WWP1 gene is the responsible one for chicken muscular dystrophy from these results, but the mechanism leading the onset should be clarified in the future. The information will contribute to the study of chicken muscular dystrophy and the corresponding human dystrophies.

• Journal of Life Science
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• v.16 no.6
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• pp.955-959
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• 2006

A dynamic cycle of addition and removal of O-linked N-acetylglucosamine (O-GlcNAc) at serine and threonine residues is emerging as a key regulator of nuclear and cytoplasmic protein activity. In this work, immunocytochemistry was carried out to investigate the subcellular expression of GlcNAc kinase (NAGK, EC 2.7.1.59) that catalyzes the phosphorylation of GlcNAc to GlcNAc 6-phosphate. Immunostainings of cultured rat hippocampal neurons revealed patchy or punctate distribution of NAGK. When NAGK is doublestained with caveolin-1 or flotillin, markers for caveolae and lipid rafts, respectively, NAGK was co-localized with these markers. These results indicate that most, if not all, of the NAGK immunopunctae represent caveolae and lipid rafts, and suggest NAGK's role in these membrane microdomains.

• BMB Reports
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• v.53 no.5
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• pp.278-283
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• 2020

Muscle fibers are generally formed as multinucleated fibers that are differentiated from myoblasts. Several reports have identified transcription factors and proteins involved in the process of muscle differentiation, but the roles of microRNAs (miRNAs) in myogenesis remain unclear. Here, comparative analysis of the miRNA expression profiles in mouse myoblasts and gastrocnemius (GA) muscle uncovered miR-3074-3p as a novel miRNA showing markedly reduced expression in fully differentiated adult skeletal muscle. Interestingly, elevating miR-3074-3p promoted myogenesis in C2C12 cells, primary myoblasts, and HSMMs, resulting in increased mRNA expression of myogenic makers such as Myog and MyHC. Using a target prediction program, we identified Caveolin-1 (Cav1) as a target mRNA of miR-3074-3p and verified that miR-3074-3p directly interacts with the 3' untranslated region (UTR) of Cav1 mRNA. Consistent with the findings in miR-3074-3p-overexpressing myoblasts, knockdown of Cav1 promoted myogenesis in C2C12 cells and HSMMs. Taken together, our results suggest that miR-3074-3p acts a positive regulator of myogenic differentiation by targeting Cav1.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.4983-4988
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• 2013

Objectives: To establish a taxol-resistant cell line of human ovarian carcinoma (A2780/Taxol) and investigate its biological features. Methods: The drug-resistant cell line (A2780/Taxol) was established by continuous stepwise selection with increasing concentrations of Taxol. Cell morphology was assessed by microscopy and growth curves were generated with in vitro and in vivo tumor xenograft models. With rhodamine123 (Rh123) assays, cell cycle distribution and the apoptotic rate were analyzed by flow cytometry (FCM). Drug resistance-related and signal associated proteins, including P-gp, MRPs, caveolin-1, PKC-${\alpha}$, Akt, ERK1/2, were detected by Western blotting. Results: A2780/Taxol cells were established with stable resistance to taxol. The drug resistance index (RI) was 430.7. Cross-resistance to other drugs was also shown, but there was no significant change to radioresistance. Compared with parental cells, A2780/Taxol cells were significantly heteromorphous, with a significant delay in population doubling time and reduced uptake of Rh123 (p<0.01). In vivo, tumor take by A2780 cells was 80%, and tumor volume increased gradually. In contrast, with A2780/Taxol cells in xenograft models there was no tumor development. FCM analysis revealed that A2780/Taxol cells had a higher percentage of G0/G1 and lower S phase, but no changes of G2 phase and the apoptosis rate. Expression of P-gp, MRP1, MRP2, BCRP, LRP, caveolin-1, PKC-${\alpha}$, Phospho-ERK1/2 and Phospho-JNK protein was significantly up-regulated, while Akt and p38 MARK protein expression was not changed in A2780/Taxol cells. Conclusion: The A2780/Taxol cell line is an ideal model to investigate the mechanism of muti-drug resistance related to overexpression of drug-resistance associated proteins and activation of the PKC-${\alpha}/ERK$ (JNK) signaling pathway.