Publication: Farklı tip ve evrelerdeki lösemilerde poliamin biyosentez ve katabolizma mekanizmasının incelenmesi
Abstract
Çocuklarda en sık görülen malign hastalık tipi akut lösemidir. Beyaz ırkta çocukluk çağında lösemi sıklığı 100.000 canlı doğumda yaklaşık 5 kadardır. Çocukluk çağında görülen kanserlerin %80'ni Akut Lenfoblastik Lösemi (ALL) oluşturmakta ve en sık 2-5 yaşları arasında görülmektedir. Poliaminler, bütün hücrelerde varlıkları kanıtlanmış pozitif yüklü alifatik amin gruplarıdır. Bunların en iyi bilinenleri, bir diamin olan putresin (Put), bir triamin olan spermidin (Spd) ve bir tetraamin olan spermin (Spm) dir. Poliaminlerin hücre bölünmesine etkileri ve RNA ile olan ilişkileri, büyüme ve protein sentezi mekanizmalarını doğrudan etkilemektedir. Ayrıca tümör karakteristiği gösteren dokularda özellikle Spd ve Spm konsantrasyonlarında artış saptanmıştır. Bu araştırma da, farklı tip ve evrelerdeki lösemi hastalarında ve bilinen hücre hatlarında poliamin metabolizmasının incelenmesi ve bu süreçlerin lösemi oluşumundaki rollerinin açıklanması amaçlanmıştır. Bu doğrultuda biyomarkır olarak poliaminlerin klinik anlamda kullanılabilirliğinin yararının saptanması amacıyla bir dizi çalışma yapılmıştır. Medikal uygulama görmemiş hastalardan alınan periferal kan lökositleri ve hastalık seviyesi belli hücre hatlarında (CCL-119 ve KG1) poliamin miktar analizleri yüksek basınçlı sıvı kromatografisi (HPLC) kullanılarak incelenmiştir. Yine aynı örneklerde poliamin katabolizmasında görevli enzimlerden diamin oksidaz (DAO) ve peroksidaz (POD) aktiviteleri spektrofotometrik olarak belirlenmiştir. Gözlemler Spd'nin hasta lökositlerinde fazla miktarda bulunduğunu göstermiştir. Ancak en belirgin sonuçlar Spm miktar tayini ile saptanmıştır. Spm kontrol örneklerine göre hastaların periferal taze lökositlerinde 20 kat, periferal kan örneklerinden yapılan süspansiyon lökosit kültürlerinde 17 kat, ALL hücre hattında 15 kat ve AML hücre hattında 10 kat artış göstermiştir (p<0,005). Buna paralel olarak hasta örneklerinde ve hücre hatlarında kontrol örneklere göre POD ve DAO aktiviteleri %100-200 oranında artış göstermiştir. Alınan sonuçlara göre Spm akut lösemilerin moleküler tanısında hassas bir biyomarkır olarak geliştirilebilir potansiyele sahiptir. İntraselüler poliamin analizi, HPLC yöntemi ile günümüzde kolay, yaygın ve ekonomik olma avantajlarına sahiptir. Aynı zamanda poliamin metabolik enzimlerinin akut lösemilerde incelenmesi geliştirilebilecek yeni terapötik maddeler için veri basamağı oluşturmaktadır. Bu nedenle poliaminlerin akut lösemiler için tanımlanması, tanı ve tedavisi süresince çeşitli yönlerden potansiyel önem taşımaktadır. INVESTIGATION OF POLYAMINE BIOSYNTHESIS AND CATABOLISM IN DIFFERENT STAGED AND TYPE LEUKEMIAS E. Damla BÜYÜKTUNÇER Marmara Üniversitesi Sağlık Bilimleri Enst. Tıbbi Biyoloji ve Genetik ABD Consulter: Prof. Dr. Beyazıt ÇIRAKOĞLU Acceptance date: 09.04.2003
The most diagnosed malign illness is acute leukemia in children. The incidence of leukemia in white population is 5 person in 100.000 live birth. 80% of childhood cancers are acute lymphoblastic leukemia (ALL) and it is seen especially between 2 and 5 years old. Polyamines are the polycationic molecules which are consisted in every kind of cell. The most known polyamines are, a diamin putrescine (Put), a triamine spermidine (Spd) and a tetraamine spermine (Spm). They directly effects cell division and RNA processes in cell and also they have relations with growth and protien synthesis. Especially polyamines are increased in tumor cells. In this research it is aimed that to reveal the importance of polyamines in different staged and characteristics leukemia patients and established leukemia cell lines. Beside of these, it is planned to determine polyamine metabolism in the same subjects. In this way, many studies were done to understand the possible usage of polyamines in clinics as a biomarker. The peripheral blood leukocytes were obtained from untreated leukemia patients. These cells and established leukemia cell lines (CCL-119 and KG1) were analyzed for polyamine content by high pressure liquid chromatography (HPLC). The same cells were investigated for polyamine catabolic enzymes, diamine oxidase (DAO) and peroxidase (POD) spectrophotometrically. Spd was found increased in patient and cell line leukocytes. However the sharpest differences were obtained from Spm content analyzes. Spm was increased 20 fold in peripheral blood leukocytes of patients, 17 fold in suspension culture of peripheral blood leukocytes, 15 fold in CLL-119 cell line and 10 fold in KG1 cell line (p<0,005). POD and DAO enzyme activities are correlated with polyamine content results. These enzymes were increased between 100 and 200% when they compared with normal subjects. Spm is a promising candidate biomarker for molecular diagnosis of leukemia. Intracellular polyamine analyzes by HPLC method is an economic, easy and applicable for wide range usage. The determinations on metabolic enzymes in leukemia patients may provide a new data step for future studies about therapeutic agents. Therefore, it is important to understand polyamine mechanisms in leukemic cells for new diagnostic and therapeutic studies.
The most diagnosed malign illness is acute leukemia in children. The incidence of leukemia in white population is 5 person in 100.000 live birth. 80% of childhood cancers are acute lymphoblastic leukemia (ALL) and it is seen especially between 2 and 5 years old. Polyamines are the polycationic molecules which are consisted in every kind of cell. The most known polyamines are, a diamin putrescine (Put), a triamine spermidine (Spd) and a tetraamine spermine (Spm). They directly effects cell division and RNA processes in cell and also they have relations with growth and protien synthesis. Especially polyamines are increased in tumor cells. In this research it is aimed that to reveal the importance of polyamines in different staged and characteristics leukemia patients and established leukemia cell lines. Beside of these, it is planned to determine polyamine metabolism in the same subjects. In this way, many studies were done to understand the possible usage of polyamines in clinics as a biomarker. The peripheral blood leukocytes were obtained from untreated leukemia patients. These cells and established leukemia cell lines (CCL-119 and KG1) were analyzed for polyamine content by high pressure liquid chromatography (HPLC). The same cells were investigated for polyamine catabolic enzymes, diamine oxidase (DAO) and peroxidase (POD) spectrophotometrically. Spd was found increased in patient and cell line leukocytes. However the sharpest differences were obtained from Spm content analyzes. Spm was increased 20 fold in peripheral blood leukocytes of patients, 17 fold in suspension culture of peripheral blood leukocytes, 15 fold in CLL-119 cell line and 10 fold in KG1 cell line (p<0,005). POD and DAO enzyme activities are correlated with polyamine content results. These enzymes were increased between 100 and 200% when they compared with normal subjects. Spm is a promising candidate biomarker for molecular diagnosis of leukemia. Intracellular polyamine analyzes by HPLC method is an economic, easy and applicable for wide range usage. The determinations on metabolic enzymes in leukemia patients may provide a new data step for future studies about therapeutic agents. Therefore, it is important to understand polyamine mechanisms in leukemic cells for new diagnostic and therapeutic studies.