Evaluation of collagen role in electroporation: two cell lines compared

Electrochemotherapy (ECT) uses electroporation to improve drug uptake into cells. This is an es tablished and effective treatment in the care of patients with several types of superficially metastatic tumors like breast cancer recurrences or melanoma. Nevertheless, is applied to other types of tu mors. In general, ECT efficacy is evaluated in vitro on cell suspensions with liquid of low conductivity or using cells in adhesion. In recent years the use of 3D culture models diffused. Cell suspension and adhesion cultures are very easy methods, nevertheless, they lack extracellular matrix components, that are found in 3D cultures or in vivo. Previously, the authors studied the effect of inhomogeneity of the scaffold materials and their electrical properties in the distribution of the electric field when voltage pulses are applied. When seeded on 3D scaffolds, the breast cancer cells or melanoma cells produced their own extracellular matrix (ECM) that induced an improvement in electroporation. In these cultures, new collagen deposition was found, and authors hypothesized that it played a role in the electroporation process. To investigate the role of collagen in the electroporation process, HELA and SCOV-3 cells were cultured in two different scaffolds. The first scaffold consisted of hyaluronic acid (HA) and 5% w/w self-assembling peptides (EAbuK) condensed with an adhesive motif mapped on Laminin (IKVAV), referred as HA-EAbuK-IKVAV. The second scaffold was HA enriched with 5% w/w calf Type I collagen (referred as HA-Collagen). The cell cultures were seeded on the scaffolds and the cultures were characterized at 3 days by cell viability assessment, hematoxylin-eosin staining, and Masson’s trichrome staining. Moreover, the gene expression for collagen was investigated. Electroporation of the cells seeded on the two types of scaffolds was performed using EPS02 EP equip ment (Igea SpA, Carpi, Modena, Italy). Different voltage amplitudes, generating different strengths of the applied electric field (0, 400, 600, 800, and 1000 V/cm), were tested. The EP efficiency was evaluated using propidium iodide. Both the 3D cultures, HA-EAbuK IKVAV and HA-Collagen, were electroporated in the culture medium. The cells cultured in the two scaffolds showed a different grade of electroporation improvement with respect to adherent cells.