Cholesterol-conjugated Sirna Accumulates in the Different Hematopoietic and Lymphoid Cells. - Cholesterol-conjugated Sirna Accumulates in the Different Hematopoietic and Lymphoid Cells. - Open Access Pub

Small interfering RNA (siRNA) based drugs for overcoming multiple drug resistance of hematological malignancies could solve the problem of poor response to the chemotherapy and hight relapse rate. The main factor that significantly limits biomedical application of siRNA is inefficient delivery to target cells and tissues. The attachment of siRNA to molecules, which enter into the cell by natural transport mechanisms, can improve cellular uptake of siRNA. In current study the carrier-free cellular uptake of siRNA containig cholesterol residues conjugated to the 5’-end of the sense strand via oligomethylene linker of various length (here and after Ch-siRNA) was explored. The data demonstrate that cholesterol residue increase the accumulation of siRNA in all tested cell lines and the primary cells. The efficiency of Ch-siRNA accumulation in K562 cells depends greatly on the leangth of the linker connecting cholesterol and siRNA: Ch-siRNAs with linker of 10 - 12 methylene units accumulate the most efficiently in this cells. It was found that Ch-siRNA effectively accumulates in MOLT-3 (acute lymphoblastic leukemia, ALL), HL-60 (acute myelogenous leukemia, AML), K562 (chronic myelogenous leukemia CML) and primary peripheral blood mononuclear cells (PBMC) from patient with non-Hodgkin lymphoma (NHL) or healthy donor resulting in near 100% of transfected cell when used at 1 mM concentration. DOI10.14302/issn.2372-6601.jhor-15-822 Since its discovery in 1998 by Fire and Mellow, siRNA has proved to be an effective tool for gene silencing in various species1, 2. siRNA have great potential as a therapeutic agent for downregulation of the abberant gene expression including expression of viral and mutated genes as welll as hyperexpression of normal genes3. It has been clearly demonstrated, that overexpression of genes, responsible for the drug efflux from cells such as MDR1, could result in clinically significant drug resistance of the tumor. This is why such genes could be used as targets for siRNA-based drugs4. The development of multidrug resistance in haematological malignancies is especially important problem because the surgical removal for this tumor type is not possible and chemotherapy is the only option for the treatment. Inefficient delivery of siRNAs to target cells and tissues is the main obstale that limits their biomedical application. Currently, various approaches have been developed to solve the problem of siRNA delivery5, 6, but they all have limitations for use in therapy. The conjugation of siRNA to the molecules, that can be internalized into the