Person: ÖZTÜRK CİVELEK, DİLEK
3 results
Search Results
Now showing 1 - 3 of 3
Publication Metadata only Synthesis of flurbiprofen thiadiazole urea derivatives and assessment of biological activities and molecular docking studies(2023-01-01) ZENGİN KURT B.; Altundağ Ö.; Tokgöz M. N.; ÖZTÜRK CİVELEK D.; Tuncay F. O.; Cakmak U.; KOLCUOĞLU Y.; Akdemir A.; Sönmez F.; ZENGİN KURT, BELMA; ÖZTÜRK CİVELEK, DİLEKTotally 15 novel flurbiprofen urea derivatives were synthesized bearing the thiadiazole ring. Their inhibition effects on tyrosinase were determined. 3c was found to be the strongest inhibitor with the IC50 value of 68.0 μM against tyrosinase. The enzyme inhibition types of the synthesized compounds were determined by examining the kinetic parameters. The inhibition type of 3c was determined as uncompetitive and the Ki value was calculated as 36.3 μM. Moreover, their cytotoxic effects on hepatocellular carcinoma (HepG2), colorectal carcinoma (HT-29), and melanoma (B16F10) cell lines were evaluated. According to the cytotoxicity results, 3l (IC50 = 14.11 μM) showed the highest cytotoxicity on the HT-29 cells, while 3o (IC50 = 4.22 μM) exhibited the strongest cytotoxic effect on HepG2 cell lines. Also, 3j (IC50 = 7.55 μM strongly affected B16F10. The effects of synthesized compounds on the healthy cell line were evaluated on the CCD-986Sk cell line. Molecular modelling studies have indicated the potential binding interactions of the uncompetitive inhibitor 3c with the enzyme-substrate complex.Publication Metadata only Novel 2-(hydrazinocarbonyl)-3-phenyl-1H-indole-5-sulfonamide based thiosemicarbazides as potent and selective inhibitors of tumor-associated human carbonic anhydrase IX and XII: Synthesis, cytotoxicity, and molecular modelling studies(2024-03-01) DEMİR YAZICI K.; Trawally M.; Bua S.; ÖZTÜRK CİVELEK D.; Akdemir A.; Supuran C. T.; GÜZEL AKDEMİR Ö.; ÖZTÜRK CİVELEK, DİLEKIn the pursuit of discovering new selective carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, a small collection of novel thiosemicarbazides (5a-5t) were designed and synthesized starting from 2-(hydrazinocarbonyl)-3-phenyl-1H-indole-5-sulfonamide which was evaluated as a potent inhibitor of different CA isoforms in a previous study. The newly synthesized compounds were examined against four human carbonic anhydrases (hCA), namely transmembrane tumor-related hCA IX/XII and cytosolic widespread off-targets hCA I/II. In enzyme inhibition assays, all nineteen compounds display up to ∼340-fold selectivity for hCA IX/XII over off-target isoforms hCA I/II. Four compounds have enzyme inhibition values (Ki) lower than 10 nM against tumor-associated isoforms hCA IX/XII including two compounds in the subnanomolar range (5r and 5s; hCA XII; Ki: 0.69 and 0.87 nM). The potential binding interactions of the most potent compounds against hCA IX and XII, compounds 5s and 5r, respectively, were investigated using ensemble docking and molecular dynamics studies. Cell viability assays using human colorectal adenocarcinoma cell line HT-29 and healthy skin fibroblasts CCD-86Sk show that compound 5e selectively inhibits HT-29 cancer cell proliferation (IC50: 53.32 ± 7.74 µM for HT-29; IC50: 74.64 ± 14.15 µM for CCD-986Sk). Finally, Western blot assays show that compounds 5e and 5r significantly reduce the expression of hCA XII in HT-29 cells. Moreover, 5e shows better cytotoxic activity in hypoxia compared to normoxic conditions. Altogether, the newly designed compounds show stronger inhibition of the tumor-associated hCA IX and XII isoforms and several tested compounds show selective cytotoxicity as well as downregulation of hCA XII expression.Publication Metadata only Dosing-time, feeding, and sex-dependent variations of everolimus pharmacokinetics in mice(2024-01-01) ÖZTÜRK CİVELEK D.; ÖZTÜRK SEYHAN N.; AKYEL Y. K.; Gazioglu I.; PALA KARA Z.; Orman M. N.; OKYAR A.; ÖZTÜRK CİVELEK, DİLEK; GAZİOĞLU, IŞILBackground: Everolimus is an oral mammalian target of rapamycin (mTOR) inhibitor used as an immunosuppressant and anticancer. Its pharmacokinetics is highly variable, it has a narrow therapeutic window and shows chronotoxicity with the best time at ZT13 and worst time at ZT1 (ZT; Zeitgeber time, time after light onset) in the preclinical setting. Objectives: In the present study, we aimed to investigate whether the pharmacokinetics of everolimus vary according to dosing time and whether sex and feeding status interfere with the chronopharmacokinetics. Method: A single dosage of 5 mg/kg everolimus was administered orally to C57BL/6J male and female mice, in fed or fasted states at ZT1-rest and ZT13-activity times and blood and tissue samples were collected at 0.5, 1, 2, 4, 12, and 24 h following drug administration. Ileum, liver, plasma, and thymus concentrations of everolimus were determined. Results: Females had a greater ileum AUC0–24h than males when fed (P = 0.043). Everolimus AUC0–24h in the liver was substantially greater at ZT1 than at ZT13 in a fasted state (P = 0.001). Plasma Cmax, AUC0–24h, and AUCtotal were not statistically significant between the groups (P = 0.098). In one of the target organs of everolimus, the thymus, males had considerably higher amounts at ZT1 than females (P = 0.029). Conclusion: Our findings imply that the pharmacokinetics of everolimus in mice may differ according to dosing time, sex, and feeding. Greater tissue distribution of everolimus at ZT1 may be associated with the worst tolerated time of everolimus. Our research suggests that oral chronomodulated everolimus therapy may be more effective and safer for cancer patients.