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1.
Chemosphere ; : 142579, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38866337

ABSTRACT

The growing number of companion dogs has contributed to a rapidly growing market for pet products, including dog toys. However, little is known about the hazardous substances released from dog toys. This study aims to examine the potential presence of obesogens, a subset of endocrine-disrupting chemicals (EDCs) that are widely utilized as raw materials in the manufacture of dog toy components, and their effects on dog health. To achieve this, we adapted and employed a migration method typically used for children's products to simulate obesogen exposure in dogs through sucking or chewing toys. We demonstrated that out of various obesogens, bisphenol A (BPA) was released from dog toys into synthetic saliva, whereas phthalates and azo dyes were not detected in any of the leachates. Additionally, we found that BPA induced adipogenic differentiation in canine adipose-derived stem cells (cADSCs). Our RNA sequencing experiments revealed that BPA alters the adipogenesis-related gene signature in cADSCs by elevating the expression levels of ADIPOQ, PLIN1, PCK1, CIDEC, and FABP4. The associated transcriptional changes are involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which may contribute to the promotion of adipogenesis by BPA. Our findings suggest that companion dogs are at risk of BPA exposure, which may contribute to obesity in dogs. Therefore, the implementation of precautionary measures is crucial.

2.
J Korean Med Sci ; 39(3): e34, 2024 Jan 22.
Article in English | MEDLINE | ID: mdl-38258366

Subject(s)
Caves , Paintings , Humans
3.
Oncol Rep ; 51(1)2024 01.
Article in English | MEDLINE | ID: mdl-38038123

ABSTRACT

Prostate cancer is the leading cause of cancer­related mortality among men worldwide. In particular, castration­resistant prostate cancer presents a formidable clinical challenge and emphasizes the need to develop novel therapeutic strategies. Forkhead box M1 (FOXM1) is a multifaceted transcription factor that is implicated in the acquisition of the multiple cancer hallmark capabilities in prostate cancer cells, including sustaining proliferative signaling, resisting cell death and the activation of invasion and metastasis. Elevated FOXM1 expression is frequently observed in prostate cancer, and in particular, FOXM1 overexpression is closely associated with poor clinical outcomes in patients with prostate cancer. In the present review, recent advances in the understanding of the oncogenic role of deregulated FOXM1 expression in prostate cancer were highlighted. In addition, the molecular mechanisms by which FOXM1 regulates prostate cancer development and progression were described, thereby providing knowledge and a conceptual framework for FOXM1. The present review also provided valuable insight into the inherent challenges associated with translating biomedical knowledge into effective therapeutic strategies for prostate cancer.


Subject(s)
Forkhead Transcription Factors , Prostatic Neoplasms , Male , Humans , Forkhead Transcription Factors/genetics , Forkhead Transcription Factors/metabolism , Forkhead Box Protein M1/genetics , Forkhead Box Protein M1/metabolism , Gene Expression Regulation, Neoplastic , Prostatic Neoplasms/pathology , Prostate/pathology , Cell Line, Tumor
4.
Oncol Rep ; 50(6)2023 12.
Article in English | MEDLINE | ID: mdl-37888771

ABSTRACT

The treatment of advanced prostate cancer remains a formidable challenge due to the limited availability of effective treatment options. Therefore, it is imperative to identify promising druggable targets that provide substantial clinical benefits and to develop effective treatment strategies to overcome therapeutic resistance. Cyclosporin A (CsA) showed an anticancer effect on prostate cancer in cultured cell and xenograft models. E2F8 was identified as a master transcription factor that regulated a clinically significant CsA specific gene signature. The expression of E2F8 increased during prostate cancer progression and high levels of E2F8 expression are associated with a poor prognosis in patients with prostate cancer. MELK was identified as a crucial upstream regulator of E2F8 expression through the transcriptional regulatory network and Bayesian network analyses. Knockdown of E2F8 or MELK inhibited cell growth and colony formation in prostate cancer cells. High expression levels of E2F8 and androgen receptor (AR) are associated with a worse prognosis in patients with prostate cancer compared with low levels of both genes. The inhibition of E2F8 improved the response to AR blockade therapy. These results suggested that CsA has potential as an effective anticancer treatment for prostate cancer, while also revealing the oncogenic role of E2F8 and its association with clinical outcomes in prostate cancer. These results provided valuable insight into the development of therapeutic and diagnostic approaches for prostate cancer.


Subject(s)
Prostatic Neoplasms , Transcription Factors , Humans , Male , Bayes Theorem , Cell Line, Tumor , Cell Proliferation , Cyclosporine/pharmacology , Cyclosporine/therapeutic use , Gene Expression Regulation, Neoplastic , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/genetics , Protein Serine-Threonine Kinases/genetics , Receptors, Androgen/genetics , Receptors, Androgen/metabolism , Repressor Proteins/genetics , Transcription Factors/genetics
5.
Biochim Biophys Acta Mol Basis Dis ; 1869(6): 166745, 2023 08.
Article in English | MEDLINE | ID: mdl-37164180

ABSTRACT

E2F8 is a multifaceted transcription factor that plays a crucial role in mediating the hallmarks of cancer, including sustaining proliferative signaling, resisting cell death, and activating invasion and metastasis. Aberrant E2F8 expression is associated with poor clinical outcomes in most human cancers. However, E2F8 also exhibits tumor-suppressing activity; thus, the role of E2F8 in cell-fate determination is unclear. In this review, we highlight the recent progress in understanding the role of E2F8 in human cancers, which will contribute to building a conceptual framework and broadening our knowledge pertaining to E2F8. This review provides insight into future challenges and perspectives regarding the translation of biological knowledge into therapeutic strategies for the treatment of cancer.


Subject(s)
Neoplasms , Signal Transduction , Humans , Cell Proliferation , Neoplasms/genetics , Neoplasms/therapy , Repressor Proteins/metabolism
6.
Exp Mol Med ; 54(8): 1225-1235, 2022 08.
Article in English | MEDLINE | ID: mdl-35999455

ABSTRACT

Crizotinib is a clinically approved tyrosine kinase inhibitor for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring EML4-ALK fusion. Crizotinib was originally developed as an inhibitor of MET (HGF receptor), which is involved in the metastatic cascade. However, little is known about whether crizotinib inhibits tumor metastasis in NSCLC cells. In this study, we found that crizotinib suppressed TGFß signaling by blocking Smad phosphorylation in an ALK/MET/RON/ROS1-independent manner in NSCLC cells. Molecular docking and in vitro enzyme activity assays showed that crizotinib directly inhibited the kinase activity of TGFß receptor I through a competitive inhibition mode. Cell tracking, scratch wound, and transwell migration assays showed that crizotinib simultaneously inhibited TGFß- and HGF-mediated NSCLC cell migration and invasion. In addition, in vivo bioluminescence imaging analysis showed that crizotinib suppressed the metastatic capacity of NSCLC cells. Our results demonstrate that crizotinib attenuates cancer metastasis by inhibiting TGFß signaling in NSCLC cells. Therefore, our findings will help to advance our understanding of the anticancer action of crizotinib and provide insight into future clinical investigations.


Subject(s)
Antineoplastic Agents , Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Antineoplastic Agents/pharmacology , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/pathology , Crizotinib/pharmacology , Crizotinib/therapeutic use , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Molecular Docking Simulation , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins , Pyrazoles/pharmacology , Pyrazoles/therapeutic use , Pyridines/pharmacology , Pyridines/therapeutic use , Transforming Growth Factor beta
7.
J Craniofac Surg ; 33(3): 920-925, 2022 May 01.
Article in English | MEDLINE | ID: mdl-34538794

ABSTRACT

ABSTRACT: The hybrid technique after bilateral sagittal split ramus osteotomy is an internal fixation method using monocortical mini-plates and additional bicortical positional screws. In this study, we analyzed the postoperative stability of 23 patients with mandibular asymmetry who underwent bilateral sagittal split ramus osteotomy and hybrid fixation with or without LeFort I osteotomy. Anatomical landmarks of the deviated and non-deviated sides of the jaw were established to measure the angle and distance to the reference plane in three-dimensional cone beam computed tomography images. We analyzed the positional changes and correlations of the reference points at preoperative (T1), postoperative 2 weeks (T2), and postoperative 1 year (T3). There were significant differences in preoperative position of the upper and lower molar cervix alveolar crest to the reference plane (U6-X and L6-X) and the condylion angles between deviated and non-deviated sides. Postoperatively (T2-T3), each reference point had no statistically significant positional change. Pearson correlation coefficient between the amount of menton deviation (ME-X at T1) and positional change of menton after surgery (T2-T3) was 0.30, and P value was 0.168. The hybrid fixation technique is an effective fixation method for achieving postoperative stability for mandibular asymmetry.


Subject(s)
Osteotomy, Sagittal Split Ramus , Prognathism , Cephalometry/methods , Cone-Beam Computed Tomography/methods , Female , Humans , Imaging, Three-Dimensional , Mandible/diagnostic imaging , Mandible/surgery , Mandibular Condyle , Osteotomy, Sagittal Split Ramus/methods , Prognathism/surgery , Retrospective Studies
8.
Life (Basel) ; 11(2)2021 Feb 20.
Article in English | MEDLINE | ID: mdl-33672474

ABSTRACT

Schisandra chinensis fruit extract (SCE) has been used as a traditional medicine for treating vascular diseases. However, little is known about how SCE and schisandrin B (SchB) affect transcriptional output-a crucial factor for shaping the fibrotic responses of the transforming growth factor ß (TGFß) signaling pathways in in vascular smooth muscle cells (VSMC). In this study, to assess the pharmacological effect of SCE and SchB on TGFß-induced transcriptional output, we performed DNA microarray experiments in A7r5 VSMCs. We found that TGFß induced distinctive changes in the gene expression profile and that these changes were considerably reversed by SCE and SchB. Gene Set Enrichment Analysis (GSEA) with Hallmark signature suggested that SCE or SchB inhibits a range of fibrosis-associated biological processes, including inflammation, cell proliferation and migration. With our VSMC-specific transcriptional interactome network, master regulator analysis identified crucial transcription factors that regulate the expression of SCE- and SchB-effective genes (i.e., TGFß-reactive genes whose expression are reversed by SCE and SchB). Our results provide novel perspective and insight into understanding the pharmacological action of SCE and SchB at the transcriptome level and will support further investigations to develop multitargeted strategies for the treatment of vascular fibrosis.

9.
Genes Genomics ; 43(4): 333-342, 2021 04.
Article in English | MEDLINE | ID: mdl-33555506

ABSTRACT

BACKGROUND: Transglutaminase 2 (TG2) mediates protein modifications by crosslinking or by incorporating polyamine in response to oxidative or DNA-damaging stress, thereby regulating apoptosis, extracellular matrix formation, and inflammation. The regulation of transcriptional activity by TG2-mediated histone serotonylation or by Sp1 crosslinking may also contribute to cellular stress responses. OBJECTIVE: In this study, we attempted to identify TG2-interacting proteins to better understand the role of TG2 in transcriptional regulation. METHODS: Using a yeast two-hybrid assay to screen a HeLa cell cDNA library, we found that TG2 bound BAF250a, a core subunit of the cBAF chromatin remodeling complex, through an interaction between the TG2 barrel 1 and BAF250a C-terminal domains. RESULTS: TG2 was pulled down with a GST-BAF250a C-term fusion protein. Moreover, TG2 and BAF250a were co-fractionated using P11 chromatography, and co-immunoprecipitated. A transamidation reaction showed that TG2 mediated incorporation of polyamine into BAF250a. In glucocorticoid response-element reporter-expressing cells, TG2 overexpression increased the luciferase reporter activity in a transamidation-dependent manner. In addition, a comparison of genome-wide gene expression between wild-type and TG2-deficient primary hepatocytes in response to dexamethasone treatment showed that TG2 further enhanced or suppressed the expression of dexamethasone-regulated genes that were identified by a gene ontology enrichment analysis. CONCLUSION: Thus, our results indicate that TG2 regulates transcriptional activity through BAF250a polyamination.


Subject(s)
DNA-Binding Proteins/metabolism , Gene Expression Regulation , Protein Glutamine gamma Glutamyltransferase 2/metabolism , Transcription Factors/metabolism , Transcription, Genetic , Amination , Animals , Cells, Cultured , DNA-Binding Proteins/chemistry , Dexamethasone/pharmacology , Glucocorticoids/pharmacology , HeLa Cells , Humans , Mice, Knockout , Protein Glutamine gamma Glutamyltransferase 2/chemistry , Protein Glutamine gamma Glutamyltransferase 2/genetics , Protein Interaction Domains and Motifs , Transcription Factors/chemistry
10.
J Korean Assoc Oral Maxillofac Surg ; 46(1): 70-77, 2020 Feb.
Article in English | MEDLINE | ID: mdl-32158684

ABSTRACT

Osteogenesis imperfecta is a heterogeneous group of connective tissue diseases that is predominantly characterized by bone fragility and skeletal deformity. Two siblings with undiagnosed type I osteogenesis imperfecta underwent orthognathic surgery for the treatment of facial asymmetry and mandibular prognathism. The authors report two cases of combined orthodontics and orthognathic surgery in patients with type I osteogenesis imperfecta, mandibular prognathism, and facial asymmetry.

11.
Korean J Physiol Pharmacol ; 24(1): 101-110, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31908579

ABSTRACT

Transient receptor potential canonical 4 (TRPC4) channel is a nonselective calcium-permeable cation channels. In intestinal smooth muscle cells, TRPC4 currents contribute more than 80% to muscarinic cationic current (mIcat). With its inward-rectifying current-voltage relationship and high calcium permeability, TRPC4 channels permit calcium influx once the channel is opened by muscarinic receptor stimulation. Polyamines are known to inhibit nonselective cation channels that mediate the generation of mIcat. Moreover, it is reported that TRPC4 channels are blocked by the intracellular spermine through electrostatic interaction with glutamate residues (E728, E729). Here, we investigated the correlation between the magnitude of channel inactivation by spermine and the magnitude of channel conductance. We also found additional spermine binding sites in TRPC4. We evaluated channel activity with electrophysiological recordings and revalidated structural significance based on Cryo-EM structure, which was resolved recently. We found that there is no correlation between magnitude of inhibitory action of spermine and magnitude of maximum current of the channel. In intracellular region, TRPC4 attracts spermine at channel periphery by reducing access resistance, and acidic residues contribute to blocking action of intracellular spermine; channel periphery, E649; cytosolic space, D629, D649, and E687.

12.
Int J Oncol ; 56(2): 559-567, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31894325

ABSTRACT

Fucosylation is a post­translational modification that attaches fucose residues to protein­ or lipid­bound oligosaccharides. Certain fucosylation pathway genes are aberrantly expressed in several types of cancer, including non­small cell lung cancer (NSCLC), and this aberrant expression is associated with poor prognosis in patients with cancer. However, the molecular mechanism by which these fucosylation pathway genes promote tumor progression has not been well­characterized. The present study analyzed public microarray data obtained from NSCLC samples. Multivariate analysis revealed that altered expression of fucosylation pathway genes, including fucosyltransferase 1 (FUT1), FUT2, FUT3, FUT6, FUT8 and GDP­L­fucose synthase (TSTA3), correlated with poor survival in patients with NSCLC. Inhibition of FUTs by 2F­peracetyl­fucose (2F­PAF) suppressed transforming growth factor ß (TGFß)­mediated Smad3 phosphorylation and nuclear translocation in NSCLC cells. In addition, wound­healing and Transwell migration assays demonstrated that 2F­PAF inhibited TGFß­induced NSCLC cell migration and invasion. Furthermore, in vivo bioluminescence imaging analysis revealed that 2F­PAF attenuated the metastatic capacity of NSCLC cells. These results may help characterize the oncogenic role of fucosylation in NSCLC biology and highlight its potential for developing cancer therapeutics.


Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , Fucose/metabolism , Fucosyltransferases/genetics , Gene Expression Regulation, Neoplastic , Lung Neoplasms/genetics , Aged , Carcinoma, Non-Small-Cell Lung/mortality , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Datasets as Topic , Disease-Free Survival , Female , Fucosyltransferases/antagonists & inhibitors , Fucosyltransferases/metabolism , Gene Expression Profiling , Glycosylation , Humans , Kaplan-Meier Estimate , Lung/pathology , Lung Neoplasms/mortality , Lung Neoplasms/pathology , Male , Middle Aged , Neoplasm Metastasis/genetics , Oligonucleotide Array Sequence Analysis , Protein Processing, Post-Translational/genetics , Survival Rate , Xenograft Model Antitumor Assays
13.
Biochim Biophys Acta Rev Cancer ; 1873(1): 188336, 2020 01.
Article in English | MEDLINE | ID: mdl-31870703

ABSTRACT

The transcription factor E2F1 plays a crucial role in mediating multiple cancer hallmark capabilities that regulate cell cycle, survival, apoptosis, metabolism, and metastasis. Aberrant activation of E2F1 is closely associated with a poor clinical outcome in various human cancers. However, E2F1 has conflictingly been reported to exert tumor suppressive activity, raising a question as to the nature of its substantive role in the control of cell fate. In this review, we summarize deregulated E2F1 activity and its role in prostate cancer. We highlight the recent advances in understanding the molecular mechanism by which E2F1 regulates the development and progression of prostate cancer, providing insight into how cell context or data interpretation shapes the role of E2F1 in prostate cancer. This review will aid in translating biomedical knowledge into therapeutic strategies for prostate cancer.


Subject(s)
Cell Cycle/genetics , E2F1 Transcription Factor/genetics , Gene Expression Regulation, Neoplastic , Prostatic Neoplasms/genetics , Disease Progression , Disease-Free Survival , E2F1 Transcription Factor/metabolism , Humans , Male , Prognosis , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/therapy
15.
Korean J Physiol Pharmacol ; 23(5): 357-366, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31496873

ABSTRACT

Gαq-coupled receptor stimulation was implied in the activation process of transient receptor potential canonical (TRPC)1/4 and TRPC1/5 heterotetrameric channels. The inactivation occurs due to phosphatidylinositol 4,5-biphosphate (PI(4,5)P2) depletion. When PI(4,5)P2 depletion was induced by muscarinic stimulation or inositol polyphosphate 5-phosphatase (Inp54p), however, the inactivation by muscarinic stimulation was greater compared to that by Inp54p. The aim of this study was to investigate the complete inactivation mechanism of the heteromeric channels upon Gαq-phospholipase C ß (Gαq-PLCß) activation. We evaluated the activity of heteromeric channels with electrophysiological recording in HEK293 cells expressing TRPC channels. TRPC1/4 and TRPC1/5 heteromers undergo further inhibition in PLCß activation and calcium/protein kinase C (PKC) signaling. Nevertheless, the key factors differ. For TRPC1/4, the inactivation process was facilitated by Ca2+ release from the endoplasmic reticulum, and for TRPC1/5, activation of PKC was concerned mostly. We conclude that the subsequent increase in cytoplasmic Ca2+ due to Ca2+ release from the endoplasmic reticulum and activation of PKC resulted in a second phase of channel inhibition following PI(4,5)P2 depletion.

16.
J Struct Biol ; 208(3): 107395, 2019 12 01.
Article in English | MEDLINE | ID: mdl-31560999

ABSTRACT

Transaminases are pyridoxal 5'-phosphate-dependent enzymes that reversibly catalyze transamination reactions from an amino group donor substrate to an amino group acceptor substrate. ω-Transaminases (ωTAs) utilize compounds with an amino group not at α-carbon position as their amino group donor substrates. Recently, a novel ωTA with broad substrate specificity and high thermostability from the thermophilic bacterium Sphaerobacter thermophilus (St-ωTA) has been reported. Although St-ωTA has been biochemically characterized, little is known about its determinants of substrate specificity. In the present study, we determined the crystal structure of St-ωTA at 1.9 Šresolution to clarify in detail its mechanism of substrate recognition. The structure of St-ωTA revealed that it has a voluminous active site resulting from the unique spatial arrangement of residues comprising its active site. In addition, our molecular docking simulation results suggest that substrate compounds may bind to active site residues via electrostatic interactions or hydrophobic interactions that can be induced by subtle rearrangements of active site residues. On the basis of these structural analyses, we propose a plausible working model of the enzymatic mechanism of St-ωTA. Our results provide profound structural insights into the substrate specificity of St-ωTA and extend the boundaries of knowledge of TAs.


Subject(s)
Chloroflexi/enzymology , Transaminases/chemistry , Transaminases/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Catalytic Domain , Crystallography, X-Ray , Molecular Docking Simulation , Protein Conformation , Pyridoxal Phosphate/metabolism , Spectrophotometry, Ultraviolet , Substrate Specificity
17.
Biochem Biophys Res Commun ; 519(2): 366-371, 2019 11 05.
Article in English | MEDLINE | ID: mdl-31519324

ABSTRACT

Zinc finger homeobox 3 (ZFHX3) is a transcription factor that regulates multiple cellular processes including cell proliferation, differentiation and neoplastic development. It is also involved in the function of steroid hormones estrogen and progesterone and the peptide hormone prolactin in mammary epithelial cells. In this study, we investigated whether and how ZFHX3 regulates intracellular calcium homeostasis in mammary epithelial cells. We found that ZFHX3 affected both store operated calcium entry and store independent calcium entry (SOCE and SICE). Simultaneously, the expression of the calcium channel TRPV6 was regulated by ZFHX3, as demonstrated by expression analysis and luciferase reporter assay. In cells with knockdown of ZFHX3, calcium entry was partially rescued by the overexpression of wild type but not the pore mutants of TRPV6. In addition, overexpression of TRPV6 promoted differentiation of the MCF10A mammary epithelial cells in three-dimensional culture, which is consistent with our previous findings that ZFHX3 is essential for mammary gland differentiation. These findings suggest that ZFHX3 plays an important role in intracellular calcium homeostasis in mammary epithelial cells, at least in part, by regulating TRPV6.


Subject(s)
Calcium Channels/metabolism , Calcium/metabolism , Epithelial Cells/metabolism , Homeodomain Proteins/metabolism , TRPV Cation Channels/metabolism , Calcium Channels/genetics , Cells, Cultured , HEK293 Cells , Humans , TRPV Cation Channels/genetics
18.
Korean J Physiol Pharmacol ; 23(3): 191-201, 2019 May.
Article in English | MEDLINE | ID: mdl-31080350

ABSTRACT

The transient receptor potential canonical (TRPC) 5 channel, known as a nonselective cation channel, has a crucial role in calcium influx. TRPC5 has been reported to be activated by muscarinic receptor activation and extracellular pH change and inhibited by the protein kinase C pathway. Recent studies have also suggested that TRPC5 is extracellularly activated by englerin A (EA), but the mechanism remains unclear. The purpose of this study is to identify the EA-interaction sites in TRPC5 and thereby clarify the mechanism of TRPC5 activation. TRPC5 channels are over-expressed in human embryonic kidney (HEK293) cells. TRPC5 mutants were generated by site-directed mutagenesis. The whole-cell patch-clamp configuration was used to record TRPC5 currents. Western analysis was also performed to observe the expression of TRPC5 mutants. To identify the EA-interaction site in TRPC5, we first generated pore mutants. When screening the mutants with EA, we observed the EA-induced current increases of TRPC5 abolished in K554N, H594N, and E598Q mutants. The current increases of other mutants were reduced in different levels. We also examined the functional intactness of the mutants that had no effect by EA with TRPC5 agonists, such as carbachol or GTPγS. Our results suggest that the three residues, Lys-554, His-594, and Glu-598, in TRPC5 might be responsible for direct interaction with EA, inducing the channel activation. We also suggest that although other pore residues are not critical, they could partly contribute to the EA-induced channel activation.

19.
Sci Rep ; 9(1): 6958, 2019 05 06.
Article in English | MEDLINE | ID: mdl-31061438

ABSTRACT

Transaminases catalyze the reversible transfer reaction of an amino group between a primary amine and an α-keto acid, utilizing pyridoxal 5'-phosphate as a cofactor. ω-transaminases (ωTAs) recognize an amino group linked to a non-α carbon of amine substrates. Recently, a novel (S)-enantioselective ωTA from Thermomicrobium roseum (Tr-ωTA) was identified and its enzymatic activity reported. However, the detailed mechanism of (S)-enantioselective substrate recognition remained unclear. In this study, we determined the crystal structure of Tr-ωTA at 1.8 Å resolution to elucidate the mechanism underlying Tr-ωTA substrate (S)-enantioselectivity. A structural analysis of Tr-ωTA along with molecular docking simulations revealed that two pockets at the active site tightly restrict the size and orientation of functional groups of substrate candidates. Based on the structural information and docking simulation results, we propose a comprehensive catalytic mechanism of Tr-ωTA. The present study thus provides structural and functional insights into the (S)-enantioselectivity of Tr-ωTA.


Subject(s)
Chloroflexi/enzymology , Pyridoxal Phosphate/metabolism , Transaminases/chemistry , Transaminases/metabolism , Catalysis , Catalytic Domain , Crystallography, X-Ray , Kinetics , Molecular Docking Simulation , Protein Conformation , Stereoisomerism , Substrate Specificity
20.
Biochim Biophys Acta Rev Cancer ; 1870(2): 198-206, 2018 12.
Article in English | MEDLINE | ID: mdl-30300679

ABSTRACT

The phosphoinositide 3-kinase (PI3K) pathway integrates multifarious environmental cues to regulate cell survival, growth, and metabolism. Hyperactivation of the PI3K pathway increases biological fitness by offering a high degree of adaptability to and resilience against diverse perturbations, thus conferring survival benefits on premalignant and transformed cells. In prostate cancer, the PI3K pathway is aberrantly activated by various genetic and epigenetic alterations and its hyperactivation is closely associated with a poor clinical outcome. In this review, we discuss the challenges encountered with clinically effective therapies targeting the PI3K pathway in prostate cancer, highlighting the clinical importance of combination therapies. In particular, we address how prostate cancer cells utilize the PI3K pathway for the development of resistance to a broad range of anticancer treatments. In addition, we describe the molecular mechanisms by which prostate cancer cells become resistant to PI3K pathway inhibitors. This review will be helpful in translating biological knowledge into therapeutic strategies for the treatment of prostate cancer and provide insight into overcoming therapeutic challenges associated with prostate cancer.


Subject(s)
Drug Resistance, Neoplasm/physiology , Phosphatidylinositol 3-Kinases/metabolism , Prostatic Neoplasms/enzymology , Animals , Humans , Male , Signal Transduction/drug effects
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