Pyrenocine A induces monopolar spindle formation and suppresses proliferation of cancer cells.

Pyrenocine A, a phytotoxin, was found to exhibit cytotoxicity against cancer cells with an IC50 value of 2.6-12.9 µM. Live cell imaging analysis revealed that pyrenocine A arrested HeLa cells at the M phase with characteristic ring-shaped chromosomes. Furthermore, as a result of immunofluorescence staining analysis, we found that pyrenocine A resulted in the formation of monopolar spindles in HeLa cells. Monopolar spindles are known to be induced by inhibitors of the kinesin motor protein Eg5 such as monastrol and STLC. Monastrol and STLC induce monopolar spindle formation and M phase arrest via inhibition of the ATPase activity of Eg5. Interestingly, our data revealed that pyrenocine A had no effect on the ATPase activity of Eg5 in vitro, which suggested the compound induces a monopolar spindle by an unknown mechanism. Structure-activity relationship analysis indicates that the enone structure of pyrenocine A is likely to be important for its cytotoxicity. An alkyne-tagged analog of pyrenocine A was synthesized and suppressed proliferation of HeLa cells with an IC50 value of 2.3 µM. We concluded that pyrenocine A induced monopolar spindle formation by a novel mechanism other than direct inhibition of Eg5 motor activity, and the activity of pyrenocine A may suggest a new anticancer mechanism.

Effect of DS-8500a, a Novel G Protein-Coupled Receptor 119 Agonist, on the Pharmacokinetics of Rosuvastatin and Atorvastatin in Healthy Subjects.

BACKGROUND: Non-clinical study data suggest that DS-8500a, a G protein-coupled receptor 119 agonist, exhibits antidiabetic activity, inhibition of some transporters and induction of cytochrome P450 (CYP) 3A. Statins are substrates for some transporters and CYP3A that may be coadministered with DS-8500a in clinical practice. OBJECTIVE: To determine the potential effects of DS-8500a on the pharmacokinetics of statins, we evaluated the effects of repeated oral administration of DS-8500a 75 mg on the pharmacokinetics of rosuvastatin and atorvastatin in healthy adults. METHODS: We performed two single-center, open-label, single-sequence studies. In Study I, subjects received single-dose rosuvastatin 10 mg (Period A) and DS-8500a 75 mg once daily + single-dose rosuvastatin 10 mg (Period B). In Study II, subjects received single-dose atorvastatin 10 mg (Period A) and DS-8500a 75 mg once daily + single-dose atorvastatin 10 mg (Period B). Primary pharmacokinetic endpoints were maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of rosuvastatin and atorvastatin. Safety was evaluated. RESULTS: In Study I, the Cmax and AUC of rosuvastatin increased by 66% and 33%, respectively, when coadministered with DS-8500a, versus rosuvastatin alone. In Study II, the Cmax of atorvastatin increased by 28%, but AUC remained unchanged following coadministration with DS-8500a, versus atorvastatin alone. Treatment-emergent adverse events were mild to moderate and mostly unrelated to the study drugs. CONCLUSIONS: Multiple doses of DS-8500a increased exposure to rosuvastatin and atorvastatin. This short-term study suggests that the impact of DS-8500a coadministration on atorvastatin exposure is limited and may not be clinically relevant. Nevertheless, caution may be necessary when patients are coadministered rosuvastatin with DS-8500a. CLINICALTRIALS. GOV IDENTIFIER: NCT03699774. JAPAN PHARMACEUTICAL INFORMATION CENTER IDENTIFIER: JapicCTI-152878.

G protein-coupled receptor 119 agonist DS-8500a effects on pancreatic ß-cells in Japanese type 2 diabetes mellitus patients.

AIMS/INTRODUCTION: Pancreatic ß-cell dysfunction contributes to type 2 diabetes mellitus progression. Drugs that improve insulin secretion might be a valuable treatment approach. The present study aimed to evaluate the effect of the G protein-coupled receptor 119 agonist DS-8500a on insulin secretory capacity in Japanese type 2 diabetes mellitus patients. MATERIALS AND METHODS: This single-center, 4-week, randomized, double-blind, cross-over study enrolled 21 Japanese drug-naïve type 2 diabetes mellitus patients aged ≥20 years with glycated hemoglobin ≥7.0 and <9.0% (NCT02669732, JapicCTI 163126). Patients received 75 mg of DS-8500a or a placebo orally daily for 4 weeks in a random order. A combined euglycemic-hyperinsulinemic and hyperglycemic clamp test was carried out to assess insulin secretion and insulin sensitivity before and after each 4-week treatment period. Primary end-points were first-phase insulin secretion (insulin area under the curve [AUC]180-190 min and C-peptide AUC180-190 min during the clamp test) and second-phase insulin secretion (insulin AUC190-300 min and C-peptide AUC190-300 min ). Insulin sensitivity (M and M/I values), disposition index and changes in lipid profile were also assessed. RESULTS: DS-8500a significantly increased first- and second-phase insulin AUC (P = 0.0011, P = 0.0112) and C-peptide AUC (P = 0.0012, P < 0.0001) compared with the placebo. At day 28, M and M/I values were comparable with those of the placebo, whereas the disposition index for insulin and C-peptide was significantly increased (P = 0.0108, P = 0.0002). Total cholesterol, low-density lipoprotein cholesterol and triglyceride concentrations were significantly reduced, and high-density lipoprotein cholesterol concentrations were significantly increased compared with the placebo. No significant treatment-emergent adverse events occurred. CONCLUSION: DS-8500a enhanced insulin secretory capacity, but not insulin sensitivity.

Cytotoxic alkylated hydroquinone, phenol, and cyclohexenone derivatives from Aspergillus violaceofuscus Gasperini.

New alkylated hydroquinones violaceoid A (1), violaceoid B (2), and violaceoid C (3), an alkylated phenol violaceoid D (4), and a cyclohexenoid violaceoid E (5) were isolated from a culture broth of Aspergillus violaceofuscus Gasperini isolated from moss. The structures were identified by interpretation of spectroscopic data (1D and 2D NMR, MS, and IR). Two known compounds, the cyclohexenoid 6 and eupenoxide (7), were also isolated. Compound 6 was isolated for the first time as a natural product and named violaceoid F. Isolated compounds were tested for cytotoxic activity against five human cancer cell lines and a mouse macrophage cell line. Violaceoid A was the most potent of the seven compounds against all cell lines. Violaceoid C and D exhibited cytotoxicity against the leukemia cell lines with LD50 values 5.9-8.3 µM, while violaceoid F was found to be cytotoxic against HCT116 and RAW264.7 with LD50 values of 6.4 and 6.5 µM, respectively. These results demonstrate that violaceoid derivatives are a new class of cytotoxic hydroquinones with a hydroxymethyl and a linear alkyl substituent.

Total synthesis of (+)-Sch 725680: inhibitor of mammalian A-, B-, and Y-family DNA polymerases.

The total synthesis of (+)-Sch 725680, a member of the hydrogenated azaphilone family, has been accomplished. The synthesis confirmed the absolute configuration and biological activities of the natural product. A key reaction to construct a hydrogenated azaphilone core skeleton is a Ti-mediated aldol reaction.

Pinophilins A and B, inhibitors of mammalian A-, B-, and Y-family DNA polymerases and human cancer cell proliferation.

Pinophilins A (1) and B (2), new hydrogenated azaphilones, and Sch 725680 (3) were isolated from cultures of a fungus (Penicillium pinophilum Hedgcok) derived from a seaweed, and their structures were determined using spectroscopic analyses. These compounds selectively inhibited the activities of mammalian DNA polymerases (pols), A (pol γ), B (pols α, δ, and ε), and Y (pols η, ι, and κ) families, but did not influence the activities of the four X-family pols (pols ß, λ, µ, and terminal deoxynucleotidyl transferase). Compound 1 was the strongest inhibitor, with IC50 values of 48.6 to 55.6 µM. Kinetic analysis showed that compound 1 is a noncompetitive inhibitor of both pol α and κ activities with the DNA template-primer substrate, and a competitive inhibitor with the nucleotide substrate. In contrast, compounds 1-3 showed no effect on the activities of plant and prokaryotic pols or any other DNA metabolic enzymes tested. The compounds suppressed cell proliferation and growth in five human cancer cell lines, but had no effect on the viability of normal human cell lines.