231 research outputs found
Peptide and peptidomimetic ligands for CXC chemokine receptor 4 (CXCR4).
The development of novel peptide and peptidomimetic ligands for the CXC chemokine receptor 4 (CXCR4) as therapeutic agents for HIV-1 infection, cancer, and immune system diseases has grown over the last decade. In this perspective article, the design of CXCR4 agonists and antagonists from endogenous stromal cell-derived factor-1 (SDF-1)/CXCL12 and horseshoe crab-derived antimicrobial peptides and their therapeutic and diagnostic applications are described
Gold(I)-Catalyzed Cascade Cyclization Reactions of Allenynes for the Synthesis of Fused Cyclopropanes and Acenaphthenes
A gold‐catalyzed reaction of phenylene‐tethered allenynes with benzofurans gave 1‐(naphth‐1‐yl)cyclopropa[b]benzofuran derivatives, whereas the reaction of 1‐allenyl‐2‐ethynyl‐3‐methylbenzene derivatives in the absence of benzofurans gave acenaphthenes in good yields. These results can be rationalized by nucleophilic attack of the alkyne moiety on an activated allene to form a vinyl cation intermediate
Synthesis of IB-01212 by multiple N-methylations of peptide bonds.
There are many natural peptides with multiple N-methylamino acids that exhibit potent attractive biological activities. N-methylation of a peptide bond(s) is also one of the standard approaches in medicinal chemistry of bioactive peptides, to improve the potency and physicochemical properties, especially membrane permeability. In this study, we investigated a facile synthesis process of N-methylated peptides via simultaneous N-methylation of several peptide bonds in the presence of peptide bonds that were not to be methylated. As a model study, we investigated the synthesis of the antiproliferative depsipeptide, IB-01212. We used a pseudoproline to protect the non-methylated peptide bond during a simultaneous N-methylation with MeI-Ag[2]O. Using further manipulations including a dimerization/cyclization process, IB-01212 and its derivatives were successfully synthesized. A preliminary structure-activity relationship study demonstrated that the symmetric structure contributed to the potent cytotoxic activity of IB-01212
Gold(I)-Catalyzed Cascade Cyclization of Anilines with Diynes: Controllable Formation of Eight-Membered Ring-Fused Indoles and Propellane-Type Indolines
Heterocycle-fused indoles or indolines are distributed widely in a variety of natural products, bioactive agents, and pharmaceuticals. Herein, we describe the development of gold-catalyzed cascade reactions of anilines with diynes to form eight-membered ring-fused indoles and propellane-type indolines, both of which proceed through an intramolecular 5-endo-dig hydroamination followed by an 8-endo-dig cycloisomerization. Controllable formation of eight-membered ring-fused indoles and propellane-type indolines was achieved through selection of the ligands and/or solvents. Protic solvents such as alcohols or IPr ligand favored the formation of eight-membered ring-fused indoles, whereas the use of Buchwald’s type ligands and/or nonpolar solvents gave propellane-type indoline predominantly. This reaction provides rapid access to two types of fused nitrogen heterocycles from simple aniline derivatives
Design and synthesis of biotin- or alkyne-conjugated photoaffinity probes for studying the target molecules of PD 404182.
To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure-activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182
The metastasis suppressor KISS1 lacks antimetastatic activity in the C8161.9 xenograft model of melanoma.
The objective of this study was to use the established xenograft model of human melanoma (C8161.9) to test a pharmacological approach to the effect of the metastasis suppressor KISS1. A KISS1 analog was used to inhibit the metastatic development of C8161.9 cells in nude mice. Further experiments were performed to test the validity of the C8161.9 model and test the connection between KISS1 expression and loss of metastatic potential. New clones of C8161.9 cells were obtained, with or without KISS1 expression, and were tested for metastasis formation. The absence of benefit in survival with the KISS1 analog compared with PBS prompted us to revisit the C8161.9 model. We found that the cells expressing KISS1, used in the previous study and obtained by transfection and single-cell cloning, were defective for both formation of orthotopic tumors and metastases. In mixing experiments, these cells could not suppress orthotopic tumor growth of KISS1-negative C8161.9 cells, suggesting that the suppression of metastasis by C8161.9-KISS1 cells may be intrinsic to the selected clone rather than related to KISS1 expression. Isolation of clones from parental C8161.9 cells in soft agar yielded cell populations that phenotypically and genotypically mimicked the KISS1-positive clone. In addition, new clones expressing KISS1 did not show any decrease in metastatic growth. These data demonstrate the heterogeneity of cell types in the C8161.9 cell line and the high risk of artifact linked to single-cell selection. A different xenograft model will be necessary to evaluate the use of KISS1 analogs as antimetastatic therapy
Telmisartan improves nonalcoholic steatohepatitis in medaka (Oryzias latipes) by reducing macrophage infiltration and fat accumulation
We investigated the efficacy of the antihypertensive drug telmisartan (Tel) and the mechanisms underlying the progression from simple steatosis to nonalcoholic steatohepatitis (NASH) in a medaka (Oryzias latipes) NASH model. We used the NASH activity score (NAS) developed in humans to assess the histology of the medaka NASH model and found that NAS increased with time. Further, TUNEL-positive apoptosis hepatocytes were found in the medaka NASH model. Tel administration resulted in the increased expression of liver peroxisome proliferator-activated receptor-γ, carnitine palmitoyltransferase 1 and acyl-CoA oxidase 1 and decreased the number of 8-hydroxydeoxyguanosine-positive hepatocytes and the migration of macrophages positive for diastase-periodic-acid-Schiff. Medaka NAS was improved by Tel administration but fatty acid content was not affected. Tel reduced the infiltration of macrophages into the liver and ameliorated NASH pathology
Total Synthesis of Zephycarinatines via Photocatalytic Reductive Radical ipso‐Cyclization
We report herein a nonbiomimetic strategy for the total synthesis of the plicamine‐type alkaloids zephycarinatines C and D. The key feature of the synthesis is a stereoselective reductive radical ipso‐cyclization using visible‐light‐mediated photoredox catalysis. This cyclization enabled the construction of a 6, 6‐spirocyclic core structure through the addition of a carbon‐centered radical onto the aromatic ring. Biological evaluation of zephycarinatines and their derivatives revealed that the synthetic derivative with a keto group displays moderate inhibitory activity against LPS‐induced NO production. This approach could offer future opportunities to expand the chemical diversity of plicamine‐type alkaloids as well as providing useful intermediates for their syntheses
Design and synthesis of amidine-type peptide bond isosteres: application of nitrile oxide derivatives as active ester equivalents in peptide and peptidomimetics synthesis.
Amidine-type peptide bond isosteres were designed based on the substitution of the peptide bond carbonyl (C=O) group with an imino (C=NH) group. The positively-charged property of the isosteric part resembles a reduced amide-type peptidomimetic. The peptidyl amidine units were synthesized by the reduction of a key amidoxime (N-hydroxyamidine) precursor, which was prepared from nitrile oxide components as an aminoacyl or peptidyl equivalent. This nitrile oxide-mediated C-N bond formation was also used for peptide macrocyclization, in which the amidoxime group was converted to peptide bonds under mild acidic conditions. Syntheses of the cyclic RGD peptide and a peptidomimetic using both approaches, and their inhibitory activity against integrin-mediated cell attachment, are presented
Is Adjuvant Chemotherapy Necessary in Patients with Early Endometrial Cancer?
Background: We investigated whether there was a difference in prognosis between patients with stage IA endometrial cancer with and without lymphovascular space invasion. Methods: We enrolled patients with stage IA (pT1aN0M0) endometrial cancer admitted to our hospital from 2009 to 2018. All patients underwent hysterectomy, bilateral salpingo-oophorectomy, and systematic pelvic lymphadenectomy. We immunopathologically evaluated the presence or absence of lymphovascular space invasion in the tumor tissue using hematoxylin and eosin, Elastica-van Gieson, and podoplanin staining. We analyzed disease-free and overall survival and calculated patients’ survival distribution using the Kaplan–Meier method and log-rank test. The multivariate analysis was performed to determine the prognostic factors. Results: A total of 116 patients were included. The median age of the patients was 57 (range, 30–78) years, and the histological subtype revealed 98 and 18 cases of types 1 and 2, respectively. The median follow-up period was 71.9 (range, 10.8–149) months, and the 3-year disease-free and 3-year overall survival rates were 94% and 99%, respectively. The disease-free and overall survival rates were significantly shorter in type 2 patients than in type 1 patients (type 2 vs. type 1; 77% vs. 97%, P < 0.01, 94% vs. 100%, P = 0.014, respectively). The univariate and multivariate analyses showed that there were no significant differences in disease-free survival between the lymphovascular space invasion-positive and -negative groups among type 1 cases. Conclusion: There was no difference in prognosis between patients with stage IA and type 1 endometrial cancer with and without lymphovascular space invasion
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