Ayşe Mine Yılmaz

Whey Protein Versus Whey Protein Hydrolyzate for the Protection of Azoxymethane and Dextran Sodium Sulfate Induced Colonic Tumors in Rats

Recent studies have shown that whey protein has many useful effects including its anti-cancer effect. In this study we have compared the protective effect of dietary whey protein with whey protein hydrolyzate against azoxymethane and dextran sodium sulfate induced colon cancer in rats. We used a rat model of the colon cancer induced by administration of azoxymethane followed by repeated dextran sodium sulfate ingestion which causes multiple tumor development. Colon tissues were analyzed histologically in addition to biochemical analyses performed by measuring lipid peroxidation, protein oxidation and glutathione levels in both of colon and liver tissues of rats after sacrification. Macroscopic and microscopic tumors were identified in all groups that received azoxymethane followed by repeated dextran sodium sulfate. Group fed with whey protein hydrolyzate showed significantly less macroscopic and microscopic tumor development compared with group fed with whey protein. The protocol applied to generate an appropriate model of colon cancer was successful. Whey protein hydrolyzate was found to be more effective in preventing colon tumor development compared with whey protein.

Quercetin-Induced Cell Death in Human Papillary Thyroid Cancer (B-CPAP) Cells

In this study, we have investigated the antiproliferative effect of quercetin on human papillary thyroid cancer cells and determined the apoptotic mechanisms underlying its actions. We have used different concentrations of quercetin to induce apoptosis and measured cell viability. Apoptosis and cell cycle analysis was determined by flow cytometry using Annexin V and propidium iodide. Finally, we have measured changes in caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP) protein expression levels as hallmarks of apoptosis and Hsp90 protein expression level as a marker of proteasome activity in treated and control cells. Quercetin treatment of human papillary thyroid cancer cells resulted in decreased cell proliferation and increased rate of apoptosis by caspase activation. Furthermore, it was demonstrated that quercetin induces cancer cell apoptosis by downregulating the levels of Hsp90. In conclusion, we have shown that quercetin induces downregulation of Hsp90 expression that may be involved in the decrease of chymotrypsin-like proteasome activity which, in order, induces inhibition of growth and causes cell death in thyroid cancer cells. Thus, quercetin appears to be a promising candidate drug for Hsp90 downregulation and apoptosis of thyroid cancer cells.

Comparison of antioxidant capacity, protein profile and carbohydrate content of whey protein fractions.

Whey is used as an additive in food industry and a dietary supplement in nutrition. Here we report a comparative analysis of antioxidant potential of whey and its fractions. Fractions were obtained by size exclusion chromatography, before and after enzymatic digestion with pepsin or trypsin. Superoxide radical scavenging, lipid peroxidation inhibition and cupric ion reducing activities of different fractions were checked. Peptides were detected by SDS-PAGE and GC-MS was used to determine carbohydrate content of the fractions. All samples showed antioxidant activity and the second fraction of the trypsin hydrolysate showed the highest superoxide radical scavenging activity. CUPRAC value of this fraction was two-times higher than that of whey filtrate. The first fraction of the pepsin hydrolysate was the most effective inhibitor of lipid peroxidation. Each sample exhibited a different polypeptide profile. Different percentages of carbohydrates were identified in whey filtrate and in all second fractions, where galactose was the major component.

Synergistic Induction of Apoptosis by Quercetin and Curcumin in Chronic Myeloid Leukemia (K562) Cells

ABSTRACT Chronic myeloid leukemia is a major hematopoietic malignancy characterized by expansion of myeloid cells. In this study, we have investigated whether quercetin, curcumin and their combination induce apoptosis and inhibit growth of K562 cells. We have observed that quercetin and curcumin combination induced apoptosis accompanied by increased ROS and decreased GSH levels as well as loss of mitochondrial membrane potential. Our mRNA and protein expression results suggested that cytochrome c was released from mitochondria causing PARP and caspase-9 cleavages, the hallmarks of mitochondrial apoptotic pathway. We believe that triggering of apoptosis is mostly via mitochondrial pathway and ROS generation may induce impairment of mitochondrial membrane potential. The use of quercetin and curcumin combination potentiates individual apoptotic effects of the polyphenols and reduces their effective dose thereby preventing potential toxic effects on normal cells. Additional preclinical studies and clinical trials are certainly required to further validate their usefulness as potent anticancer agents.

The role of HSP90 in Quercetin-induced apoptosis in human papillary thyroid (B-CPAP) cancer cells.

As in many other cancers, genetic alterations that occur in genes encoding for key proteins of major signalling pathways are the driving force for the tumorigenesis of thyroid cancer. HSP90 is an emerging therapeutic target of interest for the treatment of cancer and is responsible for modulating cellular response to stress by maintaining the function of signalling proteins. In this study, we have worked with B-CPAP, a thyroid papillary cancer cell line which is known to have BRAF V600E mutation. We have administered the flavonoid Quercetin, which is known to induce apoptosis by inhibiting HSP production on various cancer cell lines, at different concentrations (between 10 and 75µM) for 24hours. We have measured cell viability using WST-1 assay. We found that the viability decreases in a dose dependent manner. Then, we chose Quercetin concentrations between 10-75µM for 24hours, for the apoptosis and cell cycle analysis in flow cytometry by Annexin V and propidium iodide. We have also applied Hoechst stain to cancer cells for visualizing them on fluorescence microscopy and confirmed apoptosis with the presence of apoptotic signs in nuclei of cancer cells. Finally, we used Western blotting to compare HSP90 and Cleaved-PARP levels in cells treated with Quercetin and the control group. In the light of the obtained data, our results suggest that in future studies it would be useful to investigate the apoptotic mechanisms of Quercetin and use combinational therapies on BCPAP cells. Supported by Marmara University Scientific Research Commission (SAG-C-TUP-130313-0063).

Keton cisimlerinin insan meme kanseri hücrelerinde (MCF-7) canlılık üzerine etkileri

Amac: Kanser hucreleri aerobik kosullar altinda Warburg etkisi olarak bilinen artmis glikolitik fenotipini sergilerler. Ayrica, son zamanlarda yapilan calismalar, kanser hucrelerinin glikoza bagimli oldugunu ve keton cisimlerini birincil bir enerji kaynagi olarak kullanamadigini gostermistir. Bu calismada, insan meme kanseri hucrelerinin birincil enerji kaynagi olarak keton cisimlerini kullanamayacagini varsaydik ve keton cisimlerinin hucre canliligi uzerine etkisini arastirdik. Gerec ve Yontem: Bu calismada insan meme kanseri hucre hatti (MCF-7) ve insan foreskin fibroblast hucre hatti (HFF) kullanildi. Her iki hucre hattinda glukoz iceren ve icermeyen ortamlarda keton cisimleri olan asetoasetat ve beta-hidroksibutiratin hucre canliligina etkisini inceledik. Bulgular: Keton cisimlerini iceren ortamda MCF-7 hucrelerinde hucre canliligi kontrol ortami ile karsilastirildiginda azalirken, kontrol olarak kullanilan HFF hucrelerinde herhangi bir degisiklik gorulmedi. Sonuc: Elde edilen veriler isiginda, keton cisimlerinin kullanilmasi ile gerceklestirilecek beslenmenin meme kanseri tedavisinde yeni bir strateji olabilecegini dusunmekteyiz.

Effect of different culture media on isolation and differentiation of dendritic cells [Farklı besiyerlerinin dendritik hücre izolasyon ve farklılaşmasına etkisi]

Abstract Objective: Dendritic cells (DCs) are members of the mammalian immune system and are considered to be the most powerful antigen presenting cells. They are responsible for the induction of T-cells or T-cell dependent immunity and tolerance. In this study we have investigated the effect of different serum supplements on generation and yield of mature dendritic cells isolated from peripheral blood mononuclear cells. Methods: Three different serum supplements (10% Fetal Bovine Serum, 1% Human Serum Albumin and 1% autologous serum) were compared with serum-free media to identify the role and importance of serum supplements on DC cultivation. Effect of different media on maturation signs (CD40, CD80, CD86, CD209a) and cytokine release (TNF-α, IL-10, IL-12, IL-6) was examined. Results: DCs generated in serum-free media was similar to those of cells in medium with autologous serum. Few dendritic-like cells were observed in fetal bovine serum and human serum albumin. The effect of different media on maturation of DCs was compared phenotypically and increased expression of CD80, CD86 and CD209a identified maturation and yield of DCs. Conclusion: Our results suggest that serum free media can be used to overcome potential drawbacks associated with different serum containing supplements. Özet Amac: Dendritik hucreler (DC), memeli immun sistemindeki en guclu antijen sunan hucreler olarak kabul edilir. Bu hucreler, T-hucrelerin uyarılması ile T-hucre bağımlı bağışıklıktan sorumludur. Bu calışmada farklı serumların periferik kandan izole edilen mononukler hucrelerin olgun dentritik hucrelere farklılaşması uzerine etkileri araştırılmıştır. Metod: DC kulturlerindeki serum desteklerinin rolunu tanımlamak uzere, Fetal Sığır Serumu, İnsan Serum Albumini ve Otolog serum iceren besiyerlerinin etkisi serumsuz ortam ile karşılaştırılmıştır. Olgunlaşma işaretleri (CD40, CD80, CD86, CD209a) ve sitokin salınımları (TNF-α, IL-10, IL-12, IL-6) acısından incelenmiştir. Bulgular: Serumsuz ortamda farklılaştırılan hucreler ile otolog serum iceren hucrelerin benzer ozellikte olduğu buna karşılık fetal sığır serumu ile insan serum albumini iceren besiyerlerinin az sayıda dendritik hucre oluşturdukları gozlenmiştir. Farklı ortamların dendritik hucrelerdeki yuzey belirteclerinin etkisine bakıldığında CD80, CD86 ve CD209a artışı tanımlandı. Sonuc: DC uretiminde farklı faktorlerin hesaba katılması gerektiği ve serumsuz ortamların daha başarılı sonuclar verdiği duşunulmektedir.

Serbest radikaller, süt serumu proteinleri ve kolorektal kanser

Kolorektal kanser etiyolojisinde diyetin onemli bir cevresel faktor oldugu yapilan calismalarla kanitlanmistir. Total enerji alimi, yuksek yagli diyet ve kirmizi et alimi ile kolon kanseri gelisimi arasinda baglanti oldugu epidemiyolojik verilerle de desteklenmistir. Bati tarzi diyet ve pisirme teknikleri kolon kanseri icin risk faktoru olarak yer almaktadir. Ote yandan, reaktif oksijen turleri tarafindan olusturulan oksidatif stres, kanser ve norodejeneratif bozukluklar gibi yasa bagli hastaliklarda onemli rol oynamaktadir. Sut serumu proteinleri ve diger diyetsel proteinlerin reaktif oksijen radikallerini temizleme gucune sahip oldugu bildirilmistir. Hayvan calismalarinda karsinojen kullanilarak olusturulan kolon kanserine karsi sut serumu proteinlerinin koruyucu oldugu gosterilmistir. Proteinlerin yaninda protein hidrolizatlarinin da antioksidan aktivite gosterdigi bulunmustur. Protein hidrolizi sirasinda proteinin tersiyer yapisinin bozulmasi ve amino asit salinmasindaki artisa bagli olarak proteinin antioksidan aktivitesinde artis izlenmektedir. Bu derlemede, kolorektal kanser etiyopatogenezindeki mevcut bilgileri ozetlemeye ve tedavide sut serumu proteinlerinin potansiyel kullanimini irdelemeye calistik.