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456 result(s) for "Hyun-Soo Cho"
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Epigenetic Associations between lncRNA/circRNA and miRNA in Hepatocellular Carcinoma
The three major members of non-coding RNAs (ncRNAs), named microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play an important role in hepatocellular carcinoma (HCC) development. Recently, the competing endogenous RNA (ceRNA) regulation model described lncRNA/circRNA as a sponge for miRNAs to indirectly regulate miRNA downstream target genes. Accumulating evidence has indicated that ceRNA regulatory networks are associated with biological processes in HCC, including cancer cell growth, epithelial to mesenchymal transition (EMT), metastasis, and chemoresistance. In this review, we summarize recent discoveries, which are specific ceRNA regulatory networks (lncRNA/circRNA-miRNA-mRNA) in HCC and discuss their clinical significance.
Human gut-microbiome-derived propionate coordinates proteasomal degradation via HECTD2 upregulation to target EHMT2 in colorectal cancer
The human microbiome plays an essential role in the human immune system, food digestion, and protection from harmful bacteria by colonizing the human intestine. Recently, although the human microbiome affects colorectal cancer (CRC) treatment, the mode of action between the microbiome and CRC remains unclear. This study showed that propionate suppressed CRC growth by promoting the proteasomal degradation of euchromatic histone-lysine N-methyltransferase 2 (EHMT2) through HECT domain E3 ubiquitin protein ligase 2 (HECTD2) upregulation. In addition, EHMT2 downregulation reduced the H3K9me2 level on the promoter region of tumor necrosis factor α-induced protein 1 (TNFAIP1) as a novel direct target of EHMT2. Subsequently, TNFAIP1 upregulation induced the apoptosis of CRC cells. Furthermore, using Bacteroides thetaiotaomicron culture medium, we confirmed EHMT2 downregulation via upregulation of HECTD2 and TNFAIP1 upregulation. Finally, we observed the synergistic effect of propionate and an EHMT2 inhibitor (BIX01294) in 3D spheroid culture models. Thus, we suggest the anticancer effects of propionate and EHMT2 as therapeutic targets for colon cancer treatment and may provide the possibility for the synergistic effects of an EHMT2 inhibitor and microbiome in CRC treatment.
SMYD family in cancer: epigenetic regulation and molecular mechanisms of cancer proliferation, metastasis, and drug resistance
Epigenetic modifiers (miRNAs, histone methyltransferases (HMTs)/demethylases, and DNA methyltransferases/demethylases) are associated with cancer proliferation, metastasis, angiogenesis, and drug resistance. Among these modifiers, HMTs are frequently overexpressed in various cancers, and recent studies have increasingly identified these proteins as potential therapeutic targets. In this review, we discuss members of the SET and MYND domain-containing protein (SMYD) family that are topics of extensive research on the histone methylation and nonhistone methylation of cancer-related genes. Various members of the SMYD family play significant roles in cancer proliferation, metastasis, and drug resistance by regulating cancer-specific histone methylation and nonhistone methylation. Thus, the development of specific inhibitors that target SMYD family members may lead to the development of cancer treatments, and combination therapy with various anticancer therapeutic agents may increase treatment efficacy. SMYD proteins: potential therapeutic targets for cancer treatment Understanding cancer growth and spread is vital for creating new treatments. Histone methyltransferases play a key role in cancer by controlling genes that can either encourage or inhibit tumor growth. This review focuses on the SMYD family of HMTs, which are associated with cancer progression, spread, and resistance to chemotherapy. The researchers studied the structure, function, and effects of different SMYD family members on cancer, using clinical data and biological experiments. The review also explores how these enzymes can be targeted by specific inhibitors, potentially offering new cancer treatments. The findings suggest that targeting SMYD family members, especially SMYD2 and SMYD3, could be an effective cancer treatment strategy. By developing drugs that specifically inhibit SMYD2 and SMYD3, researchers hope to provide new, more effective treatments for cancer patients. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.
Interleukin-2 induces the in vitro maturation of human pluripotent stem cell-derived intestinal organoids
Human pluripotent stem cell (hPSC)-derived intestinal organoids (hIOs) form 3D structures organized into crypt and villus domains, making them an excellent in vitro model system for studying human intestinal development and disease. However, hPSC-derived hIOs still require in vivo maturation to fully recapitulate adult intestine, with the mechanism of maturation remaining elusive. Here, we show that the co-culture with human T lymphocytes induce the in vitro maturation of hIOs, and identify STAT3-activating interleukin-2 (IL-2) as the major factor inducing maturation. hIOs exposed to IL-2 closely mimic the adult intestinal epithelium and have comparable expression levels of mature intestinal markers, as well as increased intestine-specific functional activities. Even after in vivo engraftment, in vitro-matured hIOs retain their maturation status. The results of our study demonstrate that STAT3 signaling can induce the maturation of hIOs in vitro, thereby circumventing the need for animal models and in vivo maturation. Human pluripotent stem cell-derived intestinal organoids (hIOs) are a useful model with which to study intestinal development and disease, but they require in vivo maturation to resemble adult tissue. Here, the authors show that T lymphocyte-derived IL-2 induces hIO maturation in vitro through the activation of STAT3.
Catalytic DxD motif caged in Asx-turn and Met–aromatic interaction attenuates the pathogenic glycosylation of SseK2/NleB2 effectors
Pathogenic bacteria encode virulent glycosyltransferases that conjugate various glycans onto host crucial proteins, which allows adhesion to mammalian cells and modulates host cellular processes for pathogenesis. Escherichia coli NleB1, Citrobacter rodentium NleB, and Salmonella enterica SseK1/3 type III effectors fatally glycosyltransfer N -acetyl glucosamine (GlcNAc) from UDP-GlcNAc to arginine residues of death domain-containing proteins that regulate host inflammation, intra-bacterial proteins, and themselves, whose post-translational modification disrupts host immune functions and prolongs bacterial viability inside host cells. However, unlike the similar NleB1/SseK1/SseK3, E. coli NleB2 and S. enterica SseK2 show deficient GlcNAcylation and neither intra-bacterial glycosylation nor auto-glycosylation. Here, as the major factor in SseK2/NleB2 deficiency, we focused on the catalytic Asp-x-Asp (DxD) motif conserved throughout all O-/N-glycosyltransferases to coordinate Mn 2+ . All DxD motifs in apo-glycosyltransferases form Type-I-turns for binding Mn 2+ , similar to the ligand-bound DxD motif, whereas TcnA/SseK2/NleB2 DxD motifs form Asx-turns, which are unable to bind Mn 2+ . Interestingly, methionine of the NleB2 DMD motif forms triple Met–aromatic interactions, as found in age-associated diseases and tumor necrosis factor (TNF) ligand-receptor complexes. The NleB1 A222M mutation induces triple Met–aromatic interactions to steeply attenuate glycosylation activity to 3% of that in the wild type. Thus, the characteristic conformation of the DxD motif is essential for binding Mn 2+ , donors, and glycosylate targets. This explains why SseK2/NleB2 effectors with the DxD motif caged in the Asp-/Asn-turn (Asx-turn) and triple Met–aromatic interactions have lower glycosyltransferase activity than that of other fatal NleB1/SseK1/SseK3 toxins.
EHMT1 knockdown induces apoptosis and cell cycle arrest in lung cancer cells by increasing CDKN1A expression
Dozens of histone methyltransferases have been identified and biochemically characterized, but the pathological roles of their dysfunction in human diseases such as cancer remain largely unclear. Here, we demonstrate the involvement of EHMT1, a histone lysine methyltransferase, in lung cancer. Immunohistochemical analysis indicated that the expression levels of EHMT1 are significantly elevated in human lung carcinomas compared with non‐neoplastic lung tissues. Through gene ontology analysis of RNA‐seq results, we showed that EHMT1 is clearly associated with apoptosis and the cell cycle process. Moreover, FACS analysis and cell growth assays showed that knockdown of EHMT1 induced apoptosis and G1 cell cycle arrest via upregulation of CDKN1A in A549 and H1299 cell lines. Finally, in 3D spheroid culture, compared to control cells, EHMT1 knockdown cells exhibited reduced aggregation of 3D spheroids and clear upregulation of CDKN1A and downregulation of E‐cadherin. Therefore, the results of the present study suggest that EHMT1 plays a critical role in the regulation of cancer cell apoptosis and the cell cycle by modulating CDKN1A expression. Further functional analyses of EHMT1 in the context of human tumorigenesis may aid in the development of novel therapeutic strategies for cancer. Although histone methyltransferases have been previously well characterized, their role in carcinogenesis remains underexplored. In our study, we detected the overexpression of the histone lysine methyltransferase EHMT1 in lung cancer. EHMT1 modulated the gene expression of CDKN1A by regulating H3K9 dimethylation. Knockdown of EHMT1 in lung cancer cell lines upregulated CDKN1A expression and induced both apoptosis and cell cycle arrest. Our findings suggest that EHMT1 may potentially serve as a therapeutic target for the treatment of patients with lung cancer.
Structural and functional insights of AmpG in muropeptide transport and multiple β-lactam antibiotics resistance
Anhydromuropeptide permease (AmpG) is a transporter protein located in the inner membrane of certain gram -negative bacteria, involved in peptidoglycan (PG) recycling and β-lactamase induction. Decreased AmpG function reduces resistance of antibiotic-resistant bacteria to β-lactam antibiotics. Therefore, AmpG-targeting inhibitors are promising ‘antibiotic adjuvants’. However, as the tertiary structure of AmpG has not yet been identified, the development of targeted inhibitors remains challenging. We present four cryo-electron microscopy (cryo-EM) structures: the apo-inward and apo-outward state structures and the inward-occluded and outward states complexed with the substrate GlcNAc-1,6-anhMurNAc. Through functional analysis and molecular dynamics (MD) simulations, we identified motif A, which stabilizes the outward state, substrate-binding pocket, and protonation-related residues. Based on the structure of AmpG and our experimental results, we propose a muropeptide transport mechanism for AmpG. A deeper understanding of its structure and transport mechanism provides a foundation for the development of antibiotic adjuvants. Here, the authors present cryo-EM structures of Anhydromuropeptide permease in apo-inward, apo-outward, inward-occluded, and an outward-facing substrate, providing mechanistic insights into muropeptide translocation.
TRIM40 is a pathogenic driver of inflammatory bowel disease subverting intestinal barrier integrity
The cortical actin cytoskeleton plays a critical role in maintaining intestinal epithelial integrity, and the loss of this architecture leads to chronic inflammation, as seen in inflammatory bowel disease (IBD). However, the exact mechanisms underlying aberrant actin remodeling in pathological states remain largely unknown. Here, we show that a subset of patients with IBD exhibits substantially higher levels of tripartite motif-containing protein 40 ( TRIM40 ), a gene that is hardly detectable in healthy individuals. TRIM40 is an E3 ligase that directly targets Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), an essential kinase involved in promoting cell-cell junctions, markedly decreasing the phosphorylation of key signaling factors critical for cortical actin formation and stabilization. This causes failure of the epithelial barrier function, thereby promoting a long-lived inflammatory response. A mutant TRIM40 lacking the RING, B-box, or C-terminal domains has impaired ability to accelerate ROCK1 degradation-driven cortical actin disruption. Accordingly, Trim40 -deficient male mice are highly resistant to dextran sulfate sodium (DSS)-induced colitis. Our findings highlight that aberrant upregulation of TRIM40 , which is epigenetically silenced under healthy conditions, drives IBD by subverting cortical actin formation and exacerbating epithelial barrier dysfunction. The cortical actin cytoskeleton plays a role in maintaining intestinal epithelial integrity. Here the authors report that TRIM40, an E3 ligase, disrupts cortical actin formation and leads to loss of epithelial barrier integrity, and that genetic loss of TRIM40 is protective against experimental colitis in male mice.
Validation of the histone methyltransferase EZH2 as a therapeutic target for various types of human cancer and as a prognostic marker
The emphasis in anticancer drug discovery has always been on finding a drug with great antitumor potential but few side‐effects. This can be achieved if the drug is specific for a molecular site found only in tumor cells. Here, we find the enhancer of zeste homolog 2 (EZH2) to be highly overexpressed in lung and other cancers, and show that EZH2 is integral to proliferation in cancer cells. Quantitative real‐time PCR analysis revealed higher expression of EZH2 in clinical bladder cancer tissues than in corresponding non‐neoplastic tissues (P < 0.0001), and we confirmed that a wide range of cancers also overexpress EZH2, using cDNA microarray analysis. Immunohistochemical analysis showed positive staining for EZH2 in 14 of 29 cases of bladder cancer, 135 of 292 cases of non‐small‐cell lung cancer (NSCLC), and 214 of 245 cases of colorectal cancer, whereas no significant staining was observed in various normal tissues. We found elevated expression of EZH2 to be associated with poor prognosis for patients with NSCLC (P = 0.0239). In lung and bladder cancer cells overexpressing EZH2, suppression of EZH2 using specific siRNAs inhibited incorporation of BrdU and resulted in significant suppression of cell growth, even though no significant effect was observed in the normal cell strain CCD‐18Co, which has undetectable EZH2. Because EZH2 expression was scarcely detectable in all normal tissues we examined, EZH2 shows promise as a tumor‐specific therapeutic target. Furthermore, as elevated levels of EZH2 are associated with poor prognosis of patients with NSCLC, its overexpression in resected specimens could prove a useful molecular marker, indicating the necessity for a more extensive follow‐up in some lung cancer patients after surgical treatment. (Cancer Sci 2011; 102: 1298–1305)
Efficient and reproducible generation of human induced pluripotent stem cell-derived expandable liver organoids for disease modeling
Genetic liver disease modeling is difficult because it is challenging to access patient tissue samples and to develop practical and relevant model systems. Previously, we developed novel proliferative and functional liver organoids from pluripotent stem cells; however, the protocol requires improvement for standardization and reproducible mass production. Here, we improved the method such that it is suitable for scalable expansion and relatively homogenous production, resulting in an efficient and reproducible process. Moreover, three medium components critical for long-term expansion were defined. Detailed transcriptome analysis revealed that fibroblast growth factor signaling, the essential pathway for hepatocyte proliferation during liver regeneration, was mainly enriched in proliferative liver organoids. Short hairpin RNA-mediated knockdown of FGFR4 impaired the generation and proliferation of organoids. Finally, glycogen storage disease type Ia (GSD1a) patient-specific liver organoids were efficiently and reproducibly generated using the new protocol. They well maintained disease-specific phenotypes such as higher lipid and glycogen accumulation in the liver organoids and lactate secretion into the medium consistent with the main pathologic characteristics of patients with GSD1a. Therefore, our newly established liver organoid platform can provide scalable and practical personalized disease models and help to find new therapies for incurable liver diseases including genetic liver diseases.