• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9805-9812
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• 2014

Radixin, a member of the ERM (ezrin-radixin-moesin) family, plays important roles in cell motility, invasion and tumor progression. It is expressed in a variety of normal and neoplastic cells, including many types of epithelial and lymphoid examples. However, its function in glioblastomas remains elusive. Thus, in this study, radixin gene expression was first examined in the glioblastoma cells, then suppressed with a lentivirus-mediated short-hairpin RNA (shRNA) method.We found that there were high levels of radixin expression in glioblastoma U251cells. Radixin shRNA caused down-regulation of radixin gene expression and when radixin-silenced cells were implanted into nude mice, tumor growth was significantly inhibited as compared to blank control cells or nonsense shRNA cells. In addition, microvessel density in the tumors was significantly reduced. Thrombospondin-1 (TSP-1) and E-cadherin were up-regulated in radixin- suppressed glioblastoma U251 cells. In contrast, MMP9 was down-regulated. Taken together, our findings suggest that radixin is involved in GBM cell migration and invasion, and implicate TSP-1, E-cadherin and MMP9 as metastasis-inducing factors.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.753-759
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• 2012

Radixin, encoded by a gene on chromosome 11, plays important roles in cell motility, invasion and tumor progression. However, its function in pancreatic cancer remains elusive. In this study, radixin gene expression was suppressed with a lentivirus-mediated short-hairpin RNA (shRNA) method. We found that radixin shRNA caused down-regulation of radixin in PANC-1 cells, associated with inhibition of pancreatic cancer cell proliferation, survival, adhesion and invasive potential in vitro. When radixin-silenced cells were implanted in nude mice, tumor growth and microvessel density were significantly inhibited as compared to blank control cells or nonsense shRNA control cells. Thrombospondin-1 (TSP-1) and E-cadherin were up-regulated in radixin-silenced PANC-1 cells. Our results suggest that radixin might play a critical role in pancreatic cancer progression, possibly through invvolvement of down-regulation of TSP-1 and E-cadherin expression.

• BMB Reports
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• v.56 no.2
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• pp.65-70
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• 2023

Prominin-1 (PROM1), also called CD133, is a penta-span transmembrane protein that is localized in membrane protrusions, such as microvilli and filopodia. It is known to be expressed in cancer stem cells and various progenitor cells of bone marrow, liver, kidney, and intestine. Accumulating evidence has revealed that PROM1 has multiple functions in various organs, such as eye, tooth, peripheral nerve, and liver, associating with various molecular protein partners. PROM1 regulates PKA-induced gluconeogenesis, TGFβ-induced fibrosis, and IL-6-induced regeneration in the liver, associating with Radixin, SMAD7, and GP130, respectively. In addition, PROM1 is necessary to maintain cancer stem cell properties by activating PI3K and β-Catenin. PROM1-deficienct mice also show distinct phenotypes in eyes, brain, peripheral nerves, and tooth. Here, we discuss recent findings of PROM1-mediated signal transduction.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.1
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• pp.121-126
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• 2020

The ezrin-radixin-moesin (ERM) proteins are a family of membrane-associated proteins known to play roles in cell-shape determination as well as in signaling pathways. We have previously shown that amphetamine decreases phosphorylation levels of these proteins in the nucleus accumbens (NAcc), an important neuronal substrate mediating rewarding effects of drugs of abuse. In the present study, we further examined what molecular pathways may be involved in this process. By direct microinjection of LY294002, a PI3 kinase inhibitor, or of S9 peptide, a proposed GSK3β activator, into the NAcc core, we found that phosphorylation levels of ERM as well as of GSK3β in this site are simultaneously decreased. These results indicate that ERM proteins are under the regulation of Akt-GSK3β signaling pathway in the NAcc core. The present findings have a significant implication to a novel signal pathway possibly leading to structural plasticity in relation with drug addiction.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.4
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• pp.245-249
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• 2011

Amphetamine, a synthetic psychostimulant, is transported by the dopamine transporter (DAT) to the cytosol and increases the exchange of extracellular amphetamine by intracellular dopamine. Recently, we reported that the phosphorylation levels of ezrin-radixin-moesin (ERM) proteins are regulated by psychostimulant drugs in the nucleus accumbens, a brain area important for drug addiction. However, the significance of ERM proteins phosphorylation in response to drugs of abuse has not been fully investigated. In this study, using PC12 cells as an in vitro cell model, we showed that amphetamine increases ERM proteins phosphorylation and protein kinase C (PKC) ${\beta}$ inhibitor, but not extracellular signal-regulated kinase (ERK) or phosphatidylinositol 3-kinases (PI3K) inhibitors, abolished this effect. Further, we observed that DAT inhibitor suppressed amphetamine-induced ERM proteins phosphorylation in PC12 cells. These results suggest that $PKC{\beta}$-induced DAT regulation may be involved in amphetmaine-induced ERM proteins phosphorylation.

• BMB Reports
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• v.52 no.2
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• pp.111-112
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• 2019

Although many studies have reported that the breakdown of the blood-brain barrier (BBB) represents one of the major pathological changes in aging, the mechanism underlying this process remains relatively unexplored. In this study, we described that acid sphingomyelinase (ASM) derived from endothelial cells plays a critical role in BBB disruption in aging. ASM levels were elevated in the brain endothelium and plasma of aged humans and mice, resulting in BBB leakage through an increase in caveolae-mediated transcytosis. Moreover, ASM caused damage to the caveolae-cytoskeleton via protein phosphatase 1-mediated ezrin/radixin/moesin dephosphorylation in primary mouse brain endothelial cells. Mice overexpressing brain endothelial cell-specific ASM exhibited acceleration of BBB impairment and neuronal dysfunction. However, genetic inhibition and endothelial specific knock-down of ASM in mice improved BBB disruption and neurocognitive impairment during aging. Results of this study revealed a novel role of ASM in the regulation of BBB integrity and neuronal function in aging, thus highlighting the potential of ASM as a new therapeutic target for anti-aging.

• Molecules and Cells
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• v.20 no.2
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• pp.196-200
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• 2005

The neurofibromatosis type2 (NF2) tumor suppressor gene product, merlin, is structurally related to the ezrin-radixin-moesin (ERM) family of proteins that anchor the actin cytoskeleton to specific membrane proteins and participate in cell signaling. However, the basis of the tumor suppressing activity of merlin is not well understood. Previously, we identified a role of merlin as an inhibitor of the Ras-ERK signaling pathway. Recent studies have suggested that phosphorylation of merlin, as of other ERM proteins, may regulate its function. To determine whether phosphorylation of merlin affects its suppression of Ras-ERK signaling, we generated plasmids expressing full-length merlin with substitutions of serine 518, a potential phosphorylation site. A substitution that mimics constitutive phosphorylation (S518D) abrogated the ability of merlin to suppress effects of the Ras-ERK signaling pathway such as Ras-induced SRE transactivation, Elk-mediated SRE transactivation, Ras-induced ERK phosphorylation and Ras-induced focus formation. On the other hand, an S518A mutant, which mimics nonphosphorylated merlin, acted like wild type merlin. These observations show that mimicking merlin phosphorylation impairs not only growth suppression by merlin but also its inhibitory action on the Ras-ERK signaling pathway.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.192-197
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• 2007

Two distinct morphological features, leading edge and uropod, in mobile T lymphocyte are crucial for efficient directional movement. The uropod is a unique rear protrusion in migrating lymphocytes, in which several proteins, including CD44, ERM (ezrin/radixin/moesin), and F-actin cytoskeleton are concentrated and concerted. F-actin cytoskeleton is a basic mold for the shape maintenance. Rho A small GTPase acts as cytoskeleton organizer, So far, various pathways potentially can induce the Rho activation. PDZ domain is able to increase active Rho A form (Rho-GTP) level, reorganize F-actin cytoskeleton, disrupts the uropod structure and cell migration was diminished, suggesting that signaling pathways between Rho and F-artin cytoskeleton are related to uropod formation.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.201-204
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• 2020

Taenia saginata infection has seldom been reported in Cambodia. In this study, we performed a survey of intestinal parasites in 1,156 residents of Preah Vihear and Stung Treng Provinces in 2018. The results revealed that 26 (2.4%) cases were positive for Taenia spp. eggs. In order to obtain the strobilae of the tapeworms, 2 patients in Preah Vihear were treated with praziquantel and purged with magnesium salts. The proglottids expelled after the medication were morphologically and molecularly analyzed to determine the species. The main uterine lateral braches in gravid proglottids were > 15 in number suggesting that they are either T. saginata or Taenia asiatica. The sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and 2 nuclear loci, elongation factor-1 alpha (ef1) and ezrin-radixin-moesin-like protein (elp), were identical to the sequences of T. saginata available in GenBank but distant from Taenia solium, T. asiatica, and T. saginata-T. asiatica hybrid. This is the first report of the presence of T. saginata in the northern part of Cambodia bordering Lao PDR based on a molecular confirmation.

• Parasites, Hosts and Diseases
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• v.59 no.2
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• pp.179-182
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• 2021

Human infection with Taenia asiatica or a hybrid between Taenia saginata and T. asiatica has not been reported in Cambodia. We detected for the first time a hybrid form between T. saginata and T. asiatica in Preah Vihear Province, Cambodia. An adult tapeworm specimen, i.e., 75 cm long strobila without scolex, was expelled from a 27-year-old man after praziquantel medication and purging. It was morphologically indistinguishable between T. saginata and T. asiatica. Several proglottids were molecularly analyzed to confirm the tapeworm species. The mitochondrial gene encoding cytochrome c oxidase subunit 1 (cox1) and nuclear genes encoding elongation factor-1α (ef1) and ezrin-radixin-moesin (ERM)-like protein (elp) were sequenced, and a single-allele analysis was performed to confirm the haploid genotype. The results revealed that our sample showed a discrepancy between the mitochondrial and 2 nuclear genes. It possessed homozygous sequences typical of T. saginata at cox1 and ef1 loci. However, it was heterozygous at the elp locus, with 1 allele in T. asiatica (elpA) and 1 in T. saginata (elpC), which indicates that it is a hybrid between T. saginata and T. asiatica. The present results confirmed the presence of a hybrid between T. saginata and T. asiatica in Cambodia and strongly suggest the existence of also 'pure' T. asiatica in Cambodia.