Olea europaea (zeytin) yaprağı fenolik bileşeni oleuropein'in temozolomid ile birlikte hücre ölümü üzerine etkisinin glioblastoma hücrelerinde araştırılması
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Date
2017-06-12
Authors
Demirci, Hilal
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Publisher
Uludağ Üniversitesi
Abstract
Primer beyin tümörleri içerisinde en agresif fenotipe sahip Glioblastoma (GB) tedavisinde Temozolomid (TMZ) yaygın olarak kullanılmakta olup, TMZ' ye direnç gösteren mekanizmalar ve hastalığın agresif seyri tedavi etkinliğini kısıtlamaktadır. Günümüzde bitki özütlerinin ve etken maddelerinin farklı kemoterapötik ilaçlarla birlikte kombin tedavi stratejilerine odaklanılmaktadır. Mevcut tez çalışmasında, sitotoksik etkisi bilinen Olea europea yaprak özütünün (OLE) bu etkisinin ortaya çıkmasında, içeriğinde yer alan en önemli fenolik bileşen olan oleuropein (OL) rolünün araştırılması ve OL ve OLE' nin tek başlarına ve TMZ ile birlikte GB hücrelerinde (U87MG, U138MG ve T98G) apoptoz ve nekroz ile ilişkili yolaklarda görevli genlerin ekspresyon seviyelerini etkileme biçimlerini araştırarak OLE' nin GB hücrelerinde neden olduğu ölümün moleküler mekanizmasının açıklanması amaçlanmıştır. TMZ+OL' in kombin olarak uygulanan hücrelerde canlılık oranları, tek başına TMZ uygulanan hücrelere göre daha fazla olmasına rağmen, TMZ+OLE uygulanan hücrelerde, TMZ' in etkinliği artarak TMZ'nin daha düşük dozda etkin olduğu belirlenmiştir. Annexin V analizi ve AO/EB boyaması sonucunda, TMZ+ OL' de daha çok oranda apoptotik ve az oranda nekrotik, TMZ+OLE' de daha az oranda apoptotik ve daha çok oranda nekrotik ölüme neden olduğu belirlenmiştir. TMZ+OL ve TMZ+OLE uygulanan hücrelerde apoptoz, nekroz ile ilişkili genlerin ekspresyon seviyesinde değişimler değerlendirildiğinde, TMZ+OL uygulanan hücrelerde apoptotik genlerin (CASP9, BID) ekspresyon seviyesinde anlamlı kat değişimleri belirlenmesi ile birlikte TMZ+OLE uygulanan hücrelerde apoptoz (BCL2L11, BID) ve ayrıca nekroz genlerinin (FADD, RIPK1) ekspresyon seviyesinde anlamlı kat değişimleri tespit edilmiştir. Sonuç olarak, mevcut tez çalışmasında TMZ'nin OL ve OLE ile birlikte sitotoksik ve apoptotik etkisi değerlendirildiğinde, TMZ+OL' in antagonist ve TMZ+OLE'nin sinerjik etkiye sahip olduğu belirlenmiştir.
Temozolomide (TMZ) is widely used in the treatment of glioblastoma (GB) with the most aggressive phenotypes of primary brain tumors and the mechanism of resistance to TMZ and the aggressive course of the disease limit the effectiveness of treatment. Today, combination treatment strategies of different chemotherapeutic drugs with plant extracts and active ingredients, have been drawn attention. In the present thesis, we aimed to investigate the role of oleuropein (OL), the most important phenolic component in Olea europea leaf extract (OLE), which is known cytotoxic effect and explain the effects of OL or OLE alone with TMZ on molecular mechanism of death pathway by determining the expression levels of genes that potentially play a role in apoptosis and necrosis-related pathway on GB cells (U87MG, U138MG, and T98G). Although the survival rates of cells treated with a combination of TMZ + OL were higher than TMZ alone cells, TMZ+OLE combination by increasing efficacy of TMZ was more effective than just TMZ alone on these cells. As a result of Annexin V analysis and AO / EB staining, TMZ + OL triggered more apoptosis and less necrosis, whereas TMZ+OLE induced less apoptosis and more commonly necrosis were determined. When gene expression changes associated with apoptosis and necrosis were evaluated, a significant fold changes in the expression level of apoptotic genes (CASP9, BID) in cells treated with TMZ + OL as well as a significant fold changes in the expression level of necrosis genes (FADD, RIPK1) and apoptosis genes (BCL2L11, BID) in cells treated with TMZ + OLE were detected. In conclusion, when the cytotoxic and apoptotic effects of TMZ with OL and OLE were evaluated, the antagonistic effect of TMZ + OL and the synergistic effect of TMZ + OLE were determined in the present thesis.
Temozolomide (TMZ) is widely used in the treatment of glioblastoma (GB) with the most aggressive phenotypes of primary brain tumors and the mechanism of resistance to TMZ and the aggressive course of the disease limit the effectiveness of treatment. Today, combination treatment strategies of different chemotherapeutic drugs with plant extracts and active ingredients, have been drawn attention. In the present thesis, we aimed to investigate the role of oleuropein (OL), the most important phenolic component in Olea europea leaf extract (OLE), which is known cytotoxic effect and explain the effects of OL or OLE alone with TMZ on molecular mechanism of death pathway by determining the expression levels of genes that potentially play a role in apoptosis and necrosis-related pathway on GB cells (U87MG, U138MG, and T98G). Although the survival rates of cells treated with a combination of TMZ + OL were higher than TMZ alone cells, TMZ+OLE combination by increasing efficacy of TMZ was more effective than just TMZ alone on these cells. As a result of Annexin V analysis and AO / EB staining, TMZ + OL triggered more apoptosis and less necrosis, whereas TMZ+OLE induced less apoptosis and more commonly necrosis were determined. When gene expression changes associated with apoptosis and necrosis were evaluated, a significant fold changes in the expression level of apoptotic genes (CASP9, BID) in cells treated with TMZ + OL as well as a significant fold changes in the expression level of necrosis genes (FADD, RIPK1) and apoptosis genes (BCL2L11, BID) in cells treated with TMZ + OLE were detected. In conclusion, when the cytotoxic and apoptotic effects of TMZ with OL and OLE were evaluated, the antagonistic effect of TMZ + OL and the synergistic effect of TMZ + OLE were determined in the present thesis.
Description
Keywords
Temozolomid, Glioblastoma, Olea europaea, Oleuropein, Apoptoz, Nekroz, Temozolomide, Apoptosis, Necrosis
Citation
Demirci, H. (2017). Olea europaea (zeytin) yaprağı fenolik bileşeni oleuropein'in temozolomid ile birlikte hücre ölümü üzerine etkisinin glioblastoma hücrelerinde araştırılması. Yayınlanmamış yüksek lisans tezi. Uludağ Üniversitesi Sağlık Bilimleri Enstitüsü.