in activity of several transcription factors including NF-kB, AP-1, and OxyR. Many proteins are also directly responsive to DNA damage, including those responsible for DNA repair. This response often appears to act through post-translational modifications such as GSK2330672 cost phosphorylation which activates the DNA repair protein H2AX and the DNA helicase RECQ1. Further studies will be required to confirm whether these mechanisms also control transcription factors or other elements that control miRNA expression changes in response to cell stress. miRNAs are novel, highly conserved modifiers of gene expression that are responsive to various stressors including free radical stress, DNA damage, and ionizing radiation. It is clear that they represent an important mechanism by which cells can rapidly alter gene expression to respond to potentially lethal stress however the mechanisms underlying this response remain unproven. As such, the directed modulation of miRNA expression may be a useful clinical tool to alter the response of tumors and normal tissue to the effects of radiation. Typically, siRNA is introduced into 3T3-L1 adipocytes using either electroporation or purchase GSK-1278863 virally-mediated approaches. Both of these approaches have limitations in systematic siRNAmediated screening experiments, including the potential cell damage and equipment and reagent costs associated with electroporation in a high-throughput format or the complexity and safety issues associated with virally-mediated transfection. Alternatives include peptide-based transfection reagents that are highly efficient, but require sonication of the peptide prior to transfection and have not been demonstrated in fully differentiated adipocytes. Reverse transfection, also known as solid phase optimized transfection RNAi, is an alternative that uses glass plates or cell culture plates preloaded with siRNA and to which the cells of interest are then added. With improved transfection efficiency, lipid-based siRNA transfection using a version of reverse transfection in which the siRNA and cells are mixed in suspension would offer the simplest and least expensive approach to systematic screening using siRNA in adipocytes. The adipocytes would then be allowed to reattach to an adherent plate surface while in the presence of the siRNA complex. This approach has been reported in the human melanoma cell line LOX, another cell line that is considered difficult to transfect using lipid-based reagents. Herein, we present a metho
