ABSTRACT
Pesticides which are diluted and sprayed according to the pre-harvest interval (PHI) are generally decomposed and lost through various factors and pathways, and the leftover pesticides are known as residual pesticides. This study aims to determine the dissipation of residual amounts of dinotefuran, fluazinam, indoxacarb, and thiacloprid in persimmon and the changes in the concentration of various processing products. Pesticide spraying is performed in accordance with the GAP (good agricultue practice) of Korea, and the processed products are manufactured using a conventional method after removing the skin of persimmons. The modified QuEchERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method and an optimized method using LC-MS/MS (liquid chromatography mass spectrometry) is implemented to analyze the residual pesticides. The linearity, recovery, and LOQ (limit of quantitation) are presented to verify the analysis method. The amount of residual pesticides tested decreases significantly in a time-dependent manner, regardless of the minimal dilution effect present due to growth. The residual concentration does not vary significantly during the processing stage despite the removal of the systemic pesticides, dinotefuran and thiacloprid. The residues of non-systemic pesticides, fluazinam and indoxacarb, are typically removed by the peeling removal and processing methods. The reduction factor of dinotefuran, whose residual concentration is increased, is less than 1, and the absolute amount of pesticides is decreased through processing. The results of this study can be used as the scientific basis data to ensure the safety of residual pesticides in processed products in the future.
ABSTRACT
The polo-box domain (PBD) of Plk1 is a promising target for cancer therapeutics. We designed and synthesized novel phosphorylated macrocyclic peptidomimetics targeting PBD based on acyclic phosphopeptide PMQSpTPL. The inhibitory activities of 16e on Plk1-PBD is >30-fold higher than those of PMQSpTPL. Both 16a and 16e possess excellent selectivity for Plk1-PBD over Plk2/3-PBD. Analysis of the cocrystal structure of Plk1-PBD in complex with 16a reveals that the 3-(trifluoromethyl)benzoyl group in 16a interacts with Arg516 through a π-stacking interaction. This π-stacking interaction, which has not been reported previously, provides insight into the design of novel and potent Plk1-PBD inhibitors. Furthermore, 16h, a PEGlyated macrocyclic phosphopeptide derivative, induces Plk1 delocalization and mitotic failure in HeLa cells. Also, the number of phospho-H3-positive cells in a zebrafish embryo increases in proportion to the amount of 16a. Collectively, the novel macrocyclic peptidomimetics should serve as valuable templates for the design of potent and novel Plk1-PBD inhibitors.
Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Peptides, Cyclic/pharmacology , Peptidomimetics/pharmacology , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Proto-Oncogene Proteins/antagonists & inhibitors , Animals , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolism , HEK293 Cells , HeLa Cells , Humans , Molecular Docking Simulation , Molecular Structure , Peptides, Cyclic/chemical synthesis , Peptides, Cyclic/metabolism , Peptidomimetics/chemical synthesis , Peptidomimetics/metabolism , Protein Binding , Protein Domains , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/metabolism , Protein Serine-Threonine Kinases/chemistry , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins/metabolism , Structure-Activity Relationship , Zebrafish , Polo-Like Kinase 1ABSTRACT
Transforming growth factor-ß activated kinase-1 (TAK1) is a potential therapeutic target for cancers and inflammatory diseases. We synthesized a series of novel imidazopyrazine derivatives, which were found to exhibit potent inhibitory effect against TAK1. Compound 22a, which possesses a good pharmacokinetic profile, showed excellent in vitro kinase activity and significant in vivo efficacy in mice xenografted with SW620, a KRAS-dependent colon cancer cell line.
Subject(s)
MAP Kinase Kinase Kinases/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Pyrazines/therapeutic use , Animals , Cell Line, Tumor , Colonic Neoplasms/drug therapy , Colonic Neoplasms/pathology , Heterografts , Humans , Inflammation/drug therapy , Mice , Neoplasms/drug therapy , Pyrazines/chemical synthesis , Pyrazines/pharmacokinetics , Pyrazines/pharmacologyABSTRACT
Colony stimulating factor-1 receptor (CSF-1R or FMS) and it ligand, CSF-1, signaling regulates the differentiation and function of tumor-associated macrophages (TAMs) that play an important role in tumor progression. Derivatives of thieno[3,2-d]pyrimidine were synthesized and evaluated as kinase inhibitors of FMS. The most representative compound 21 showed strong activity (IC50â¯=â¯2â¯nM) against FMS kinase and served as candidate for proof of concept. Anti-tumor activity alone and/or in combination with paclitaxel was examined via a tumor cell growth inhibition assay and via an in vitro tumor invasion assay using human breast adenocarcinoma cells.
Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/drug therapy , Protein Kinase Inhibitors/pharmacology , Pyrimidines/pharmacology , Receptor, Macrophage Colony-Stimulating Factor/antagonists & inhibitors , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Female , Humans , Ligands , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Receptor, Macrophage Colony-Stimulating Factor/metabolism , Structure-Activity RelationshipABSTRACT
Activating mutations involving the PI3K pathway occur frequently in human cancers. However, PI3K inhibitors primarily induce cell cycle arrest, leaving a significant reservoir of tumor cells that may acquire or exhibit resistance. We searched for genes that are required for the survival of PI3K mutant cancer cells in the presence of PI3K inhibition by conducting a genome scale shRNA-based apoptosis screen in a PIK3CA mutant human breast cancer cell. We identified 5 genes (PIM2, ZAK, TACC1, ZFR, ZNF565) whose suppression induced cell death upon PI3K inhibition. We showed that small molecule inhibitors of the PIM2 and ZAK kinases synergize with PI3K inhibition. In addition, using a microscale implementable device to deliver either siRNAs or small molecule inhibitors in vivo, we showed that suppressing these 5 genes with PI3K inhibition induced tumor regression. These observations identify targets whose inhibition synergizes with PI3K inhibitors and nominate potential combination therapies involving PI3K inhibition.
