Tumor electrotransfection progress and prospects: The impact of knowledge about tumor histology

Abstract

In order to improve transfection efficiency of electrotransfer to solid tumors in vivo, we explored how tumor histological properties affected transfection efficiency. In four different tumor types (B16F1, EAT, SA-1, LPB), the content of proteoglycans and collagen was morphometrically analyzed and the cell size as well as cell density determined. To demonstrate the influence of histological properties of solid tumors on electrotransfer correlation between histological properties and transfection efficiency with regard to the time interval between DNA injection and electroporation was determined. Our data demonstrate that soft tumors with spherical and larger cell size, low proteoglycans and collagen content and low cell density are more effectively transfected (B16F1, EAT) than rigid tumors with high proteoglycans and collagen content, small and spindle-shaped cells and high cell density (LPB and SA-1). Furthermore, the optimal time interval for increased transfection exists only in soft tumors, being around 5 to 15 min.