Developing and evaluating studies on sirna delivery systems

Cancer, which is one of today's most important health problem, lead to the formation of mass or tumor which is characterized by uncontrolled cell proliferation. Uncontrolled proliferation was the result of unrealized apoptosis due to mutations in DNA (activation of oncogene, inactivation of tumor supressor genes etc.).siRNA was first discovered in mammalian cells by Tuschl et al. in 2001. And since than it is being used for the treatment of many cancer cases for the both inhibition of angiogenesis and various oncogenes and intracellular signal transduction system genes to stop tumor growth and induction of apoptosis and also increasement of the sensitivity of the radio or chemotherapy.In this study, we aimed to use of different lipidic and polymeric systems for this technology. We formulated ?Solid Lipid Nanoparticles? (SLN) and water soluble chitosan polymers which are newly developed and not much studied on as lipidik and polymeric structure respectively Bcl-2 siRNA was choosen as the genetic material.A variety of methods (sonication, simple emulsion with high speed mixing) were used for the preparation of SLN and were evaluated for the zeta potential, particle size, cytotoxicity, siRNA binding ability. S5 was the best formulation that was prepared with sonication and also G2 was the best formulation thar was prepared with high speed stirring in terms of the all features and was selected as the most appropriate formulation for transfection studies. In chitosan studies, for the preparation different molecular-weight water soluble chitosans were used the polymeric formulations. And also they were evaluated for characterisation, cytotoxicity, efficacy of siRNA binding. When the results were evaluated, The 10 kDa molecular weight Kitosan (K4) was the best candidate for further transfection studies.As the results of the transfection stdies, When the S5 formulations have showed closer transfection actvitiy compared to Lipofectamin®2000 which was used as a control, K4 showed not much activity in A549 and MCF-7 cells. In the Westen blot sudies which is made for the analysis of the effectiveness of transfection, especially in the 72th hours, the inhibition of Bcl-2 protein was observed with S5 formulations according to K4.