Transport of cytotoxic cyanine dyes coupled to siRNA into hematopoietic cancer cells with CD20-, CD22- or CD33-targeting ELART nanocarriers.

The efficient and safe transfection of hematopoietic cells is a major hurdle that limits efficacy of therapeutic approaches like RNA-interference. We therefore used our modular ELectrostatic Antibody siRNA Targeted therapy platform (ELART) to develop nanocarriers decorated with antibodies for delivery of siRNA into hematopoietic CD20-, CD22-, or CD33-positive cells. To analyze internalization efficacy into tumor cells, we applied nanocarriers loaded with Cy3- or Cy5-labeled siRNA and reached nearly all target cells within 1-4 h. Exposure to Cy5-labeled non-functional siRNAs resulted in reduction of the mitochondrial membrane potential and reduced viability, as detected in tetramethylrhodamine methyl ester (TMRM) and CellTiter-Glo (CTG) assays. We concluded that with our modular nanocarrier system, we can transport cytotoxic agents such as cyanine dyes when bound to siRNA, as ELART nanocarriers safely complex anionic siRNA electrostatically and releases it intracellularly within the target cell. This proof-of-concept study shows that ELART nanocarriers can transport anti-cancer agents utilizing siRNA as carrier substance.