Gen tedavisi ve biyogüvenlik

Gen tedavisi hastalıkları tedavi etmek veya önlemek amacıyla bir kişinin genlerinin ekspresyonunun değiştirilmesi olarak tanımlanabilir. Akademik ve ticari laboratuvarların zorlu çalışmaları ile 2006 yılı verilerine göre 1273 gen tedavisi klinik deneme protokolü etik çevrelerce onaylanmıştır. Ancak henüz sadece baş-boyun kanserleri için geliştirilen bir gen tedavisi ürünü rutin kullanım için Çin'de lisans alabilmiştir. Gen tedavisi denemelerindeki başarısızlıklar terapötik genlerin yetersizliğinden kaynaklanmamaktadır. Başanlı gen tedavisinin önündeki en önemli engel toksik olmayan gen aktarım sistemlerinin olmayışıdır. Gen tedavisinde viral ve viral olmayan çeşitli vektör sistemleri kullanılmaktadır ve her biri kendine özgü avantaj ve dezavantajlara sahiptir. Günümüzde en etkili gen aktarım araçları, genlerini hedef hücreye aktarma özellikleri nedeniyle, virüslerdir. Gen tedavisi kalıtsal tek gen hastalıkları ve kardiyovasküler hastalıkları da içine alan bir dizi hastalığın tedavisi amacıyla geliştirilmekteyse de özellikle kanser tedavisi daha öne çıkmaktadır. Gen tedavisinin pratikte yaygın uygulama alanı bulabilmesi tedavi genlerinin hücrelere yeterli dozlarda aktarılabilmesine, genin hastalıklı hücreleri hedefleyebilmesine ve aktarılan yeni genlerin vücut tarafından sıkı kontrol altında tutulabilme yollarının geliştirilmesine ve dolayısıyla da biyogüvenlik problemlerinin aşılmasına bağlıdır. Bu derlemede gen tedavisinde kullanılan vektör sistemleri anlatılacak ve biyogüvenirlik açısından değerlendirme kriterleri tartışılacaktır.

Gene therapy and biosafety

Gene therapy can be described as the approach to change gene expression of an individual to treat a disease. According to the annual gene therapy records in 2006, hard work of both academic and industrial laboratories resulted 1273 gene therapy clinical protocols that have been approved by ethical commitees. In spite of all these attempts there is only one licence so far and that has recently been given by China for the routine use of head and neck cancer treatment. A major obstacle to the successful application of gene therapy trials is not a insufficient amount of therapeutic genes, but the lack of nontoxic gene delivery systems. A variety of viral and non-viral systems are used for gene therapy and each system owns its specific advantages and disadvantages. In the current status, the most effective gene delivery tools are viruses because of their natural ability to transfer genes to target cells. Gene therapy is being developed for a range of diseases including inherited monogenic disorders and cardiovascular diseases, but this approach has been most evident for cancer. In order that gene therapy can be used in clinical practice, delivery of therapeutic genes to cells at efficient doses, gene-targetting to the disease cells and tight-control of the delivered genes should be improved, by another means, biosafety problems needs to be solved. In this review, vector systems used in gene therapy will be explained and evaluation criterias for their biosafety will be discussed.

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