siRNA therapy in cutaneous T-cell lymphoma cells using polymeric carriers

Cutaneous T-cell lymphomas (CTCLs) arise from specific molecular aberrations that lead to uncontrolled cell proliferation. RNA interference (RNAi) with short interfering RNAs (siRNAs) is a feasible approach to interrupt aberrant signal processing in CTCL cells, but functional biomaterial carriers are needed to effectively deliver siRNAs intracellularly. Towards this goal, we explored the utility of lipid-substituted polyethylenimines (PEI) carriers in a cell model of CTCL. Using caprylic and linoleic acid substituted 2 kDa PEI (PEI-CA and PEI-LA, respectively), we showed effective delivery of siRNA to T-lymphocyte Hut78 and Jurkat cells, but silencing of a model protein (Green Fluorescent Protein, GFP) was possible only in the Hut78 cells. To enhance siRNA delivery to Hut78 cells, a high siRNA: carrier ratio used to assemble the complexes and centrifugation of cells in the presence of complexes were found effective. The toxicities of PEI-CA and PEI-LA were significantly lower than other commercial carriers, 25 kDa PEI and Lipofectamine® RNAiMAX. This might have contributed to reduced siRNA delivery efficiency of the latter carriers. Screening several endogenous targets led us to identify phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and cyclin-dependent kinase 18 (CDK18) as viable targets to induce siRNA-mediated cell growth inhibition. The results of this study identified promising polymeric carriers and molecular targets that could control proliferation of CTCL cells based on RNAi therapy.