Publications by authors named "Jaegal Shim"

The growth of Caenorhabditis elegans involves multiple molting processes, during which old cuticles are shed and new cuticles are rapidly formed. This process requires the regulated bulk secretion of cuticle components. The transmembrane protein-39 (TMEM-39) mutant exhibits distinct dumpy and ruptured phenotypes characterized by notably thin cuticles.

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Article Synopsis
  • Animals show phenotypic plasticity through gene-environment interactions, and this study explores genetic factors affecting synaptic function during development in the nematode C. elegans.
  • Researchers found that while the dauer larval stage (which is stress-resistant) typically has reduced sensitivity to many chemicals, it is unusually sensitive to the cholinesterase inhibitor aldicarb.
  • The gene cyp-34A4 (or dach-1), which encodes a cytochrome P450, is key in modulating this sensitivity and also plays roles in regulating quiescence and stress resistance in dauer larvae, highlighting its importance in developmental plasticity.
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The loss of cell-matrix interactions induces apoptosis, known as anoikis. For successful distant metastasis, circulating tumor cells (CTCs) that have lost matrix attachment need to acquire anoikis resistance in order to survive. Cell aggregate formation confers anoikis resistance, and CTC clusters are more highly metastatic compared to single cells; however, the molecular mechanisms underlying this aggregation are not well understood.

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The extracellular matrix (ECM) is important for normal development and disease states, including inflammation and fibrosis. To understand the complex regulation of ECM, we performed a suppressor screening using expressing the mutant ROL-6 collagen protein. One cuticle mutant has a mutation in that encodes the μ2 adaptin (AP2M1) of clathrin-associated protein complex II (AP-2).

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Anoikis is a type of apoptosis induced by cell detachment from the extracellular matrix (ECM), which removes mislocalized cells. Acquisition of anoikis resistance is critical for cancer cells to survive during circulation and, thus, metastasize at a secondary site. Although the sensitization of cancer cells to anoikis is a potential strategy to prevent metastasis, the mechanism underlying anoikis resistance is not well defined.

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Glioblastoma is a type of aggressive brain tumor that grows very fast and evades surrounding normal brain, lead to treatment failure. Glioblastomas are associated with Akt activation due to somatic alterations in PI3 kinase/Akt pathway and/or PTEN tumor suppressor. Sodium meta-arsenite, KML001 is an orally bioavailable, water-soluble, and trivalent arsenical and it shows antitumoral effects in several solid tumor cells via inhibiting oncogenic signaling, including Akt and MAPK.

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Article Synopsis
  • Metastasis is the leading cause of cancer deaths, and sensitizing cancer cells to anoikis could help prevent this.
  • Pygenic acid A (PA), found in natural compounds, has shown promise by inducing apoptosis and making triple-negative breast cancer cells more susceptible to anoikis.
  • PA works by downregulating pro-survival proteins, triggering ER stress and autophagy, and ultimately reducing metastatic behaviors and lung metastasis in mouse models, suggesting potential for a new therapeutic approach against breast cancer.
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Lung cancer is the major cause of cancer-associated death worldwide, and development of new therapeutic drugs is needed to improve treatment outcomes. Three-dimensional (3D) tumorspheroids offer many advantages over conventional two-dimensional cell cultures due to the similarities to in vivo tumors. We found that isoharringtonine, a natural product purified from Nakai, significantly inhibited the growth of tumorspheroids with NCI-H460 cells in a dose-dependent manner and induced apoptotic cell death in our 3D cell culture system.

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The epidermal growth factor receptor (EGFR) signaling is important for normal development, such as vulval development in , and hyperactivation of the EGFR is often associated with cancer development. Our previous report demonstrated the multivulva (Muv) phenotype, a tumor model in ( strain) by engineering LET-23/EGFR with a TKI-resistant human EGFR T790-L858 mutant. Because Rab proteins regulate vesicle transport, which is important for receptor signaling, we screened the RNAi in the strain to find the Rabs critical for Muv formation.

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Bioinformatic and functional data link integrin-mediated cell adhesion to cellular senescence; however, the significance of and molecular mechanisms behind these connections are unknown. We now report that the focal adhesion-localized βPAK-interacting exchange factor (βPIX)-G protein-coupled receptor kinase interacting protein (GIT) complex controls cellular senescence in vitro and in vivo. βPIX and GIT levels decline with age.

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Novel strategies for overcoming multidrug resistance are urgently needed to improve chemotherapy success and reduce side effects. Ginsenosides, the main active components of , display anti-cancer properties and reverse drug resistance; however, the biological pathways mediating this phenomenon remain incompletely understood. This study aimed to evaluate the anti-cancer effects of ginsenoside Rp1, actinomycin D (ActD), and their co-administration in drug-resistant cells and murine xenograft model of colon cancer, and explore the underlying mechanisms.

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Doxorubicin is a widely used DNA damage-inducing anti-cancer drug. However, its use is limited by its dose-dependent side effects, such as cardiac toxicity. Cholesterol-lowering statin drugs increase the efficacy of some anti-cancer drugs.

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Genetically engineered animal tumor models have traditionally been generated by the gain of single or multiple oncogenes or the loss of tumor suppressor genes; however, the development of live animal models has been difficult given that cancer phenotypes are generally induced by somatic mutation rather than by germline genetic inactivation. In this study, we developed somatically mutated tumor models using TALEN-mediated somatic gene inactivation of or tumor suppressor genes in zebrafish. One-cell stage injection of -TALEN mRNA resulted in malignant peripheral nerve sheath tumors with high frequency (about 39%) and early onset (about 35 weeks of age) in F0 mutant zebrafish.

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Rab escort protein-1 (REP1) is linked to choroideremia (CHM), an X-linked degenerative disorder caused by mutations of the gene encoding REP1 (CHM). REP1 mutant zebrafish showed excessive cell death throughout the body, including the eyes, indicating that REP1 is critical for cell survival, a hallmark of cancer. In the present study, we found that REP1 is overexpressed in human tumor tissues from cervical, lung, and colorectal cancer patients, whereas it is expressed at relatively low levels in the normal tissue counterparts.

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Rab escort protein 1 (REP1) is a component of Rab geranyl-geranyl transferase 2 complex. Mutations in REP1 cause a disease called choroideremia (CHM), which is an X-linked eye disease. Although it is postulated that REP1 has functions in cell survival or death of various tissues in addition to the eye, how REP1 functions in normal and cancer cells remains to be elucidated.

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Article Synopsis
  • Cells that survive crises can become cancerous, often by reactivating telomerase, but some use a different method called alternative lengthening of telomeres (ALT).
  • Research in Caenorhabditis elegans shows that ALT survivors can escape sterility by duplicating certain genomic regions across telomeres, leading to genomic changes.
  • These regions, termed 'Template for ALT' (TALT), are characterized by telomere-like sequences and vary between different genetic backgrounds, suggesting a model for how ancestral duplications prepare these regions for telomere incorporation during ALT activation.
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The World Health Organization (WHO) has reported that cancer is one of the most prevalent diseases and a leading cause of death worldwide. Many anticancer drug development studies have been pursued over the last few decades and several viable drugs have been discovered, such as paclitaxel, topotecan and irinotecan. Previously, our research group uncovered the cytocidal and cytostatic effects of the plant Stephania delavayi Diels.

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The early event of microtubule-kinetochore attachment is a critical stage for precise chromosome segregation. Here we report that NCAPG2, which is a component of the condensin II complex, mediates chromosome segregation through microtubule-kinetochore attachment by recruiting PLK1 to prometaphase kinetochores. NCAPG2 colocalizes with PLK1 at prometaphase kinetochores and directly interacts with the polo-box domain (PBD) of PLK1 via its highly conserved C-terminal region.

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TopBP1 was initially identified as a topoisomerase II-β-binding protein and it plays roles in DNA replication and repair. We found that TopBP1 is expressed at high levels in lymphoid tissues and is essential for early lymphocyte development. Specific abrogation of TopBP1 expression resulted in transitional blocks during early lymphocyte development.

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Lipid rafts, plasma membrane microdomains, are important for cell survival signaling and cholesterol is a critical lipid component for lipid raft integrity and function. DHA is known to have poor affinity for cholesterol and it influences lipid rafts. Here, we investigated a mechanism underlying the anti-cancer effects of DHA using a human breast cancer cell line, MDA-MB-231.

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Perinuclear reorganization via phosphorylation of specific serine residues in keratin is involved in the deformability of metastatic cancer cells. The level of leukotriene B₄ is high in pancreatic cancers. However, the roles of LTB₄ and its cognate receptors in keratin reorganization of pancreatic cancers are not known.

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The epidermal growth factor receptor (EGFR) is a well-established target for cancer treatment. EGFR tyrosine kinase (TK) inhibitors, such as gefinitib and erlotinib, have been developed as anti-cancer drugs. Although non-small cell lung carcinoma with an activating EGFR mutation, L858R, responds well to gefinitib and erlotinib, tumors with a doubly mutated EGFR, T790M-L858R, acquire resistance to these drugs.

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Novel anti-inflammatory compounds were synthesised by derivatization of militarin, a compound isolated from Cordyceps militaris that is an ethnopharmacologically well-known herbal medicine with multiple benefits such as anti-cancer, anti-inflammatory, anti-obesity, and anti-diabetic properties. In this study, we explored the in vitro and in vivo anti-inflammatory potencies of these compounds during inflammatory responses, their inhibitory mechanisms, and acute toxicity profiles. To do this, we studied inflammatory conditions using in vitro lipopolysaccharide-treated macrophages and several in vivo inflammatory models such as dextran sodium sulphate (DSS)-induced colitis, EtOH/HCl-induced gastritis, and arachidonic acid-induced ear oedema.

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The nuclear factor κB (NF-κB)/inhibitor of κ kinase-β (IKKβ) signaling pathway is important in tumor promotion and progression. MDA-MB-231 human breast carcinoma cells express COX-2 and show a constitutive phosphorylation of NF-κB. Many non-specific inhibitors of IKKβ and NF-κB are used to inhibit tumor promotion and progression.

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The regulation of AMPA-type glutamate receptor (AMPAR) membrane trafficking is a key mechanism by which neurons regulate synaptic strength and plasticity. AMPAR trafficking is modulated through a combination of receptor phosphorylation, ubiquitination, endocytosis, and recycling, yet the factors that mediate these processes are just beginning to be uncovered. Here we identify the ubiquitin-conjugating enzyme variant UEV-1 as a regulator of AMPAR trafficking in vivo.

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