• Journal of Pharmaceutical Investigation
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• 제22권1호
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• pp.11-21
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• 1992

The effects of colchicine on the plasma elimination and biliary excretion of various organic anions in rats were examined. Elimination of indocyanine green (ICG) or rose bengal (RB) from plasma was significantly delayed when rats were treated with colchicine (3 mg/kg body weight) 3 hr prior to the administration of the dye. On the other hand, disappearance of sulfobromophthalein (BSP) or bromophenol blue (BPB) from plasma was not influenced by colchicine. The plasma disappearance and biliary excretion of organic anions were kinetically analyzed based on a compartment model, in which the deep compartment and the unknown disposition are incorporated. The transfer rate constants of ICG or RB, $k_{23}$ (from the liver to the deep compartment) and $k_{3B}$ (from the deep compartment to the bile), were decreased by colchicine, but those of BSP or BPB were not changed. A mechanism for the decrease in the $k_{23}$ and $k_{3B}$ values for ICG and RB might be explained by a inhibition of colchicine to the intracellular cytoskeleton. The hepatocellular distribution of RB or BPB was then determined. BPB mainly distributed to the cytosolic fraction, but RB distributed to each hepatocyte organelle. Taken together. it was suggested that ICG or RB is transported through hepatocytes into bile with the aid of the cytoskeleton, whereas BSP or BPB is handled by hepatocytes in a different way.

• Animal cells and systems
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• 제1권1호
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• pp.93-98
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• 1997

The present study investigated the cellular localization of a-subunit of Gq (Gaq) protein in developing L8E63, rat skeletal muscle cell line. The colocalization of Gaq with actin cytoskeleton was demonstrated by double-labeling experiments. In mononucleated myoblasts, the immuno-fluorescence staining pattern of Gaq was almost identical with that of F-actin visualized with rhodamine-conjugated phalloidin. However, this colocalization of Gaq with cytoskeleton was not maintained in multinucleated myotubes. The staining pattern of Gaq in myotubes did not match with any specific subcellular structure, but appeared as a uniformly distributed diffuse staining throughout the whole cell surface. Interestingly, change in the expression level of Gaq was not detected during myoblast differentiation, suggesting that actin-associated Gaq protein might dissociate from the cytoskeleton as cells differentiate. Immunocytochemical experiments using specific antibodies directed against several G proteins indicated that the subcellular localizations of Gai1, Gai2, Gai3, and Gao were different from those obtained with Gaq.

• Clinical and Experimental Reproductive Medicine
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• 제38권1호
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• pp.1-5
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• 2011

The maturation process of mammalian oocytes accompanies an extensive rearrangement of the cytoskeleton and associated proteins. As this process requires a delicate interplay between the cytoskeleton and its regulators, it is often targeted by various external and internal adversaries that affect the congression and/or segregation of chromosomes. Asymmetric cell division in oocytes also requires specific regulators of the cytoskeleton, including formin-2 and small GTPases. Recent literature providing clues regarding how actin filaments and microtubules interact during spindle migration in mouse oocytes are highlighted in this review.

• Clinical and Experimental Reproductive Medicine
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• 제26권3호
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• pp.363-368
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• 1999

연구목적: 본 연구는 동해방지제인 EFS40을 이용한 초자화동결이 생쥐 미성숙란의 cytoskeleton과 염색체의 성상에 미치는 영향을 indirect immunocytochemistry방법과 염색체 분석법으로 알아보고자 실시하였다. 연구재료 및 방법: 본 실험은 생쥐 미성숙란을 EFS40 (40% ethylene glycol, 18% ficou과 0.5 M sucrose가 들어있는 M2배양액)으로 초자화 동결하여 융해한 후 16시간동안 체외 성숙을 유도하여, 제 1극체가 나타난 성숙된 난자를 기준으로 동해제노출군 또는 대조군과 비교 조사하였다. 결과: 초자화동결된 미성숙란의 응해 후 생존율과 체외성숙율은 90.3%과 64.7%로써, 동해제노출군 (86.7%, 69.2%)과 대조군 (100%, 58.3%)에 유사하였다. 초자화동결이 미성숙란의 microtubule과 microfilament에 미치는 영향을 조사하였던 바, 동결군의 microtubule과 micro-filament의 정상적인 형성율 (93.9%, 100.0%)은 동해 제노출군 (94.4%, 100.0%)과 대조군 (100.0%, 100.0%)의 성적과 유사하게 나타났다. 또한, 초자화동결군에서 정상적인 염색체수를 가진 난자의 비율도 65.8%로써, 대조군(79.6%)과 노출군 (69.0%)의 결과와 유의한 차이가 없었다. 결론: 생쥐 미성숙란을 EFS40에 노출하고 동결하는 것이 미성숙란의 cytoskeleton과 염색체성상에 영향을 미치지 않으며, 본 연구에서 사용된 EFS40을 이용한 초자화동결법은 생쥐 미성숙란 동결에 적합하다는 것을 알 수 있었다.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.269-270
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• 2008

Single polarization modulation polariscopic microscope for visualization of cytoskeleton was proposed for the first time. Algorithm of the single polarization modulation polariscopic microscope has beeen explained and accuracy and precision of the single polarization modulation polariscopic microscope have been measured in this paper.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10245-10250
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• 2015

Background: Glucocorticoids are commonly co-administered with chemotherapy to prevent drug-induced allergic reactions, nausea, and vomiting, and have anti-tumor functions clinically; however, the distinct effects of GC on subtypes of tumor cells, especially in breast cancer cells, are still not well understood. In this study, we aimed to clarify the effect of GC on subtypes of T47D breast cancer cells by focusing on apoptosis, cell organization and migration, and underluing molecular mechanisms. Materials and Methods: The cell scratch test was performed to observe the cell migration rate in T47D cells treated with dexamethasone (Dex). Hoechst and MTT assays were conducted to detect cell survival and rhodamine-labeled phalloidin staining to observe cytoskeleton dynamics. Related factors in the AKT/mTOR pathway were determined by Western blotting. Results: Dex treatment could effectively inhibit T47D breast cancer cell migration with disruption of the cytoskeletal dynamic organization. Moreover, the effect of Dex on cell migration and cytoskeleton may be mediated by AKT/mTOR/RhoA pathway. Although Dex inhibited T47D cell migration, it alone may not induce cell apoptosis in T47D cells. Conclusions: Dex in T47D human breast cancer cells could effectively inhibit cell migration by disrupting the cytoskeletal dynamic organization, which may be mediated by the AKT/mTOR/RhoA pathway. Our work suggests that glucocorticoid/Dex clinical use may prove helpful for the treatment of breast cancer metastasis.

• 대한의생명과학회지
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• 제14권3호
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• pp.179-186
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• 2008

Matrix metalloproteinases (MMPs), also designated matrixins, hydrolyze components of the extracellular matrix. These proteinases playa central role in many biological processes, such as embryogenesis, normal tissue remodeling, wound healing, and angiogenesis, and in diseases such as atheroma, arthritis, cancer, and tissue ulceration. In previous data, disruption of the actin cytoskeleton by cytochalasin D (CD) inhibited NO-induced apoptosis, dedifferentiation, cyclooxygenase (COX)-2 expression, and prostaglandin $E_2$ production in chondrocytes cultured on plastic or during cartilage explants culture. In this study, we investigated the effects of the actin cytoskeleton architecture on MMP-2 expression and dedifferentiation by CD in rabbit articular chondrocytes. Rabbit articular chondrocytes were prepared from cartilage slices of 2-weeks-old New Zealand white rabbits by enzymatic digestion. CD was used as a disruptor of actin cytoskeleton. In this experiments measuring CD dose response, primary chondrocytes were treated with various concentrations of CD for 24h. The actin disruption was determined by immunostaining. MMP-2 expression levels were determined by immunoblot analysis and Reverse transcriptase-Polymerase chain reaction (RT-PCR) and MMP-2 activity was determined by gelatin zymography. We found that cell morphological change and up-regulation of MMP-2 expression by CD as determined via immunostaining, gelatin zymography and immunoblotting. Moreover, CD induced MMP-2 transcription was detected by RT-PCR. Also, CD-induced type II collagen expression was inhibited by MMP-2 inhibitor I treatment. Our results indicate that CD up-regulated MMP-2 activation causes dedifferentiation of articular chondrocyte.

• The Korean Journal of Physiology and Pharmacology
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• 제18권2호
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• pp.109-120
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• 2014

The epothilones are a class of microtubule inhibitors that exhibit a strong antitumor activity. UTD2 is a novel epothilone analog generated by genetic manipulation of the polyketide biosynthetic gene cluster. This study investigated the effects of UTD2 on the actin cytoskeleton and its critical regulators, and the signaling pathways which are essential for cell motility, growth and survival in MCF-7 breast cancer cells. Results showed that UTD2 inhibited the cellular functions of actin cytoskeleton, such as wound-closure, migration and invasion, as well as adhesion. Our study further demonstrated that UTD2 suppressed Rac1 GTPase activation and reduced the activity of PAK1, which is a downstream effector of Rac1, while the activity of Cdc42 was not affected. Additionally, the phosphorylation of p38 and ERK were significantly inhibited, but the phosphorylation of JNK remained the same after UTD2 treatment. Moreover, UTD2 inhibited the activity and mRNA expression of MMP-2, which plays a key role in cell motility. UTD2 also reduced the phosphorylation of Akt, which is an important signaling kinase regulating the cell survival through Rac1. Furthermore, UTD2 interrupted the synergy between Rac1 and Raf in focus formation assays. Taken together, these results indicated that UTD2 exerted multiple effects on the actin cytoskeleton and signaling pathways associated with Rac1. This study provided novel insights into the molecular mechanism of the antineoplastic and antimetastatic activities of epothilones. Our findings also suggest that the signaling pathways regulated by Rac1 may be evaluated as biomarkers for the response to therapy in clinical trials of epothilones.

• 한국발생생물학회지:발생과생식
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• 제26권1호
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• pp.23-36
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• 2022

Pharyngeal pouches, a series of outgrowths of the pharyngeal endoderm, are a key epithelial structure governing facial skeleton development in vertebrates. Pouch formation is achieved through collective cell migration and rearrangement of pouch-forming cells controlled by actin cytoskeleton dynamics. While essential transcription factors and signaling molecules have been identified in pouch formation, regulators of actin cytoskeleton dynamics have not been reported yet in any vertebrates. Cofilin1-like (Cfl1l) is a fish-specific member of the Actin-depolymerizing factor (ADF)/Cofilin family, a critical regulator of actin cytoskeleton dynamics in eukaryotic cells. Here, we report the expression and function of cfl1l in pouch development in zebrafish. We first showed that fish cfl1l might be an ortholog of vertebrate adf, based on phylogenetic analysis of vertebrate adf and cfl genes. During pouch formation, cfl1l was expressed sequentially in the developing pouches but not in the posterior cell mass in which future pouch-forming cells are present. However, pouches, as well as facial cartilages whose development is dependent upon pouch formation, were unaffected by loss-of-function mutations in cfl1l. Although it could not be completely ruled out a possibility of a genetic redundancy of Cfl1l with other Cfls, our results suggest that the cfl1l expression in the developing pouches might be dispensable for regulating actin cytoskeleton dynamics in pouch-forming cells.

• Animal cells and systems
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• 제13권1호
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• pp.17-23
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• 2009

In previous studies, we found that Annexin I (Anx I) was co-secreted with insulin in response to glucose, and that extracellular Anx I stimulated the release of insulin via the Anx I binding site in rat pancreatic islets and the &-cell line. However, the role that Anx I plays in the insulin secretion was not established. Therefore, in this study, we evaluated the insulin secretion pattern in response to Anx I and the involvement of the cytoskeleton or PKC in Anx Istimulated insulin secretion in MIN6N8a cells. The peak time of insulin secretion in response to Anx I treatment corresponded with the second phase insulin secretion by glucose in the perifused pseudoislets. In addition, Anx I-stimulated insulin secretion was not affect by readily releasable pool depletion. Taken together, these findings indicate that Anx I treatment was associated with movement of the reserve pool of insulin. Furthermore, Anx I-stimulated insulin secretion was attenuated by treatment with a microfilament inhibitor, cytochalasin B, as well as by PKC down regulation. These results indicate that Anx I may be a regulator of second phase insulin secretion.