Yazar "Ozgun, G. S." seçeneğine göre listele

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    The cytotoxic concentration of rosmarinic acid increases MG132-induced cytotoxicity, proteasome inhibition, autophagy, cellular stresses, and apoptosis in HepG2 cells
    (Sage Publications Ltd, 2020) Ozgun, G. S.; Ozgun, E.
    Rosmarinic acid (RA) is a natural polyphenolic compound derived from many common herbal plants. Although it is known that RA has many important biological activities, its effect on proteasome inhibitor-induced changes in cancer treatment or its effects on any experimental proteasome inhibition model is unknown. The aim of the study was to investigate the effect of RA on MG132-induced cytotoxicity, proteasome inhibition, autophagy, cellular stresses, and apoptosis in HepG2 cells. HepG2 cells were treated with 10, 100, and 1000 mu M RA in the presence of MG132 for 24 h; 10 and 100 mu M RA did not affect but 1000 mu M RA decreased cell viability in HepG2 cells. MG132 caused a significant decrease in cell viability and phosphorylation of mammalian target of rapamycin and a significant increase in levels of polyubiquitinated protein, microtubule-associated proteins 1A/1B light chain 3B-II (LC3B-II), heat shock protein 70 (HSP70), binding immunoglobulin protein (BiP), activating transcription factor 4 (ATF4), protein carbonyl, and cleaved poly(adenosine diphosphate-ribose) polymerase 1 (PARP1); 10 and 100 mu M RA did not significantly change these effects of MG132 in HepG2 cells; 1000 mu M RA caused a significant decrease in cell viability and a significant increase in polyubiquitinated protein, LC3B-II, HSP70, BiP, ATF4, protein carbonyl, and cleaved PARP1 levels in MG132-treated cells. Our study showed that only 1000 mu M RA increased MG132-induced cytotoxicity, proteasome inhibition, autophagy, cellular stresses, and apoptosis in HepG2 cells. According to our results, cytotoxic concentration of RA can potentiate the effects of MG132 in hepatocellular carcinoma treatment.
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    Effect of Lipoic Acid on Serum Paraoxonase-1 and Paraoxonase-3 Protein Levels and Activities in Diabetic Rats
    (Johann Ambrosius Barth Verlag Medizinverlage Heidelberg Gmbh, 2019) Ozgun, E.; Ozgun, G. S.; Gokmen, S. S.; Eskiocak, S.; Sut, N.; Akinci, M.; Goncu, E.
    The aim of the present study was to investigate the effect of streptozotocin-induced diabetes mellitus and lipoic acid treatment on serum paraoxonase-1 and paraoxonase-3 protein levels and paraoxonase, arylesterase and lactonase activities. 36 rats were equally and randomly divided into 4 groups as control, lipoic acid, diabetes and diabetes + lipoic acid. To induce diabetes, a single dose of streptozotocin (40 mg/kg) was injected intraperitoneally to diabetes and diabetes + lipoic acid groups. Lipoic acid (10 mg/kg/day) was injected intraperitoneally for 14 days to lipoic acid and diabetes + lipoic acid groups. Serum PON1 and PON3 protein levels were measured bywestern blotting. Serum paraoxonase, arylesterase and lactonase activities were determined by the measuring initial rate of substrate (paraoxon, phenylacetate and dihydrocoumarin) hydrolysis. Streptozotocin-induced diabetes mellitus caused a significant decrease whereas lipoic acid treatment caused a significant increase in serum PON1 and PON3 protein levels and paraoxonase, arylesterase and lactonase activities. The increase percent of serum PON3 protein was higher than that of serum PON1 protein and the increase percent of serum lactonase activity was higher than that of serum paraoxonase and arylesterase activities in diabetes + lipoic acid group. We can report that, like PON1 protein, PON3 protein and actually its lactonase activity may also have a role as an antioxidant in diabetes mellitus and lipoic acid treatment may be useful for the prevention of the atherosclerotic complications of diabetes by increasing serum PON1 and PON3 protein levels and serum enzyme activities.