Akt1 silencing efficiencies in lung cancer cells by sh/si/ssiRNA transfection using a reductable polyspermine carrier

Efforts directed in ameliorating silencing studies with shRNA, siRNA and ssiRNA (siRNA with sticky overhangs) are faltered mainly due to the lack of efficient carrier system. In the present study, we developed reductable polyspermine (RPS) carrier composed of multiple spermine units with disulfide linkages for gene expression and silencing studies. In gene expression studies, EGFP expression was found to be almost 4 folds higher and 20 folds safer with RPS carrier than with PEI25K. Moreover, on systemic administration, RPS exhibited significantly high EGFP expression in mice lungs. Similarly in gene silencing studies, EGFP silencing achieved was nearly 1.5 times superior with RPS carrier than PEI25K. Also, RPS delivered Akt1 shRNA (shAkt), siRNA (siAkt) and ssiRNA (ssiAkt) efficiently silenced oncoprotein Akt1 and thereby decreased A549 cell survival. The degrees of cell survival, proliferation and metastasis were differed with the nature of siRNA treatment. Further study at different time intervals revealed that ssiAkt treatment, although superior to sh/siAkt, was highly transient while, shAkt treatment was uniform and prolong. These finding demonstrate the potential use of RPS carrier in gene expression and silencing studies, and significance of the nature of siRNA employed in cancer study.