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Cho CC, Lin CJ, Huang HH, Yang WZ, Fei CY, Lin HY, Lee MS, Yuan HS. Mechanistic Insights into Harmine-Mediated Inhibition of Human DNA Methyltransferases and Prostate Cancer Cell Growth. ACS Chem Biol 2023; 18:1335-1350. [PMID: 37188336 PMCID: PMC10278071 DOI: 10.1021/acschembio.3c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/24/2023] [Indexed: 05/17/2023]
Abstract
Mammalian DNA methyltransferases (DNMTs), including DNMT1, DNMT3A, and DNMT3B, are key DNA methylation enzymes and play important roles in gene expression regulation. Dysregulation of DNMTs is linked to various diseases and carcinogenesis, and therefore except for the two approved anticancer azanucleoside drugs, various non-nucleoside DNMT inhibitors have been identified and reported. However, the underlying mechanisms for the inhibitory activity of these non-nucleoside inhibitors still remain largely unknown. Here, we systematically tested and compared the inhibition activities of five non-nucleoside inhibitors toward the three human DNMTs. We found that harmine and nanaomycin A blocked the methyltransferase activity of DNMT3A and DNMT3B more efficiently than resveratrol, EGCG, and RG108. We further determined the crystal structure of harmine in complex with the catalytic domain of the DNMT3B-DNMT3L tetramer revealing that harmine binds at the adenine cavity of the SAM-binding pocket in DNMT3B. Our kinetics assays confirm that harmine competes with SAM to competitively inhibit DNMT3B-3L activity with a Ki of 6.6 μM. Cell-based studies further show that harmine treatment inhibits castration-resistant prostate cancer cell (CRPC) proliferation with an IC50 of ∼14 μM. The CPRC cells treated with harmine resulted in reactivating silenced hypermethylated genes compared to the untreated cells, and harmine cooperated with an androgen antagonist, bicalutamide, to effectively inhibit the proliferation of CRPC cells. Our study thus reveals, for the first time, the inhibitory mechanism of harmine on DNMTs and highlights new strategies for developing novel DNMT inhibitors for cancer treatment.
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Affiliation(s)
- Chao-Cheng Cho
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
| | - Chun-Jung Lin
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
- Graduate
Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, Republic of China
| | - Hsun-Ho Huang
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
- Graduate
Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, Republic of China
| | - Wei-Zen Yang
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
| | - Cheng-Yin Fei
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
| | - Hsin-Ying Lin
- Graduate
Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, Republic of China
| | - Ming-Shyue Lee
- Graduate
Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, Republic of China
| | - Hanna S. Yuan
- Institute
of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic
of China
- Graduate
Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, Republic of China
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Specht AJ, Kponee K, Nkpaa KW, Balcom PH, Weuve J, Nie LH, Weisskopf MG. Validation of x-ray fluorescence measurements of metals in toenail clippings against inductively coupled plasma mass spectrometry in a Nigerian population<sup/>. Physiol Meas 2018; 39:085007. [PMID: 30091720 DOI: 10.1088/1361-6579/aad947] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Metal exposures have been linked with many adverse health outcomes affecting nearly every system in the body. Exposure to metals has been tracked primarily using blood. Blood metal concentrations have drawbacks as biomarkers stemming from the metals' short biologic half-lives, shipping and storage requirements, and invasive collection procedures. Toenails, which capture a longer exposure period, can be collected non-invasively and stored at room temperature, and can be more feasible and cost-effective for large-scale population studies. APPROACH Inductively coupled plasma mass spectrometry (ICP-MS) has been used for analysis of toenail metal concentrations, but x-ray fluorescence (XRF) has many advantages in versatility and cost effectiveness over these analyses. This study compared toenail concentrations of manganese (Mn) and lead (Pb) measured with XRF against ICP-MS, in samples collected from 20 adults in Nigeria. To do this we developed a novel calibration method that corrects XRF measurements for toenail weight and thickness to reduce the variability in XRF measurements of toenail clippings. MAIN RESULTS We found a high correlation (R = 0.91) between toenail manganese metal measurements made with XRF and ICP-MS and a correlation of (R = 0.32) between toenail lead XRF and ICP-MS with over half of the lead results below the detection limit of the instrumentation. SIGNIFICANCE XRF can be used effectively to quantify metals at the part per million level or lower depending on the XRF equipment used in the measurements.
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Affiliation(s)
- Aaron J Specht
- Harvard T.H. Chan School of Public Health, Boston, MA, United States of America. Author to whom any correspondence should be addressed
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Chen JL, Yang PC, Wu T, Lin YW. Determination of mercury (II) ions based on silver-nanoparticles-assisted growth of gold nanostructures: UV-Vis and surface enhanced Raman scattering approaches. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 199:301-307. [PMID: 29627614 DOI: 10.1016/j.saa.2018.03.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/19/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
Innovative dual detection methods for mercury(II) ions (Hg(II)) have been developed based on the formation of gold nanostructures (AuNSs) following the addition of mercury-containing solution to a mixture containing an optimized amount of Au(III), H2O2, HCl, and silver nanoparticles (AgNPs). In the absence of Hg(II), the addition of Au(III), H2O2, and HCl to the AgNP solution changes the solution's color from yellow to red, and the absorption peak shifts from 400 to 526nm, indicating the dissolution of AgNPs and the formation of gold nanoparticles (AuNPs). Because of the spontaneous redox reaction of Hg(II) toward AgNPs, the change in the amount of remaining AgNP seed facilitates the generation of irregular AuNSs, resulting in changes in absorption intensity and shifting the peak within the range from 526 to 562nm depending on the concentration of Hg(II). Under optimal conditions, the limit of detection (LOD) for Hg(II) at a signal-to-noise ratio (S/N) of 3 was 0.3μM. We further observed that AgNP-assisted catalytic formation of Au nanomaterials deposited on a surface enhanced Raman scattering active substrate significantly reduced the Raman signal of 4-mercaptobenzoic acid, dependent on the Hg(II) concentration. A linear relationship was observed in the range 0.1nM-100μM with a LOD of 0.05nM (S/N 3.0). As a simple, accurate and precise method, this SERS-based assay has demonstrated its success in determining levels of Hg(II) in real water samples.
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Affiliation(s)
- Jun-Liang Chen
- Department of Chemistry, National Changhua University of Education, 1 Jin-De road, Changhua City, Changhua County 500, Taiwan
| | - Pei-Chia Yang
- Department of Chemistry, National Changhua University of Education, 1 Jin-De road, Changhua City, Changhua County 500, Taiwan
| | - Tsunghsueh Wu
- Department of Chemistry, University of Wisconsin-Platteville, 1 University Plaza, Platteville, WI 53818-3099, USA.
| | - Yang-Wei Lin
- Department of Chemistry, National Changhua University of Education, 1 Jin-De road, Changhua City, Changhua County 500, Taiwan.
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