Electrochemotherapy: variable anti-tumor effect on different tumor models

Electrochemotherapy is a new approach in the treatment of tumors that takes advantage of the permeabilization of the cell membrane by electric pulses to facilitate the delivery of chemotherapeutic drugs into the cells, According to the procedures described previously, the anti-tumor effectiveness of electrochemotherapy with bleomycin (BLM) was tested on three different murine tumor models, with different biological characteristics, to determine the variability in anti-tumor response. An arrest of growth of fibrosarcoma SA-I, malignant melanoma B-16 and Ehrlich ascites tumor (EAT) was observed in all mice subjected to electrochemotherapy, whereas neither BLM nor electric pulses had an effect on tumor growth when compared with controls. Partial and complete responses were also observed. The best anti-tumor response was observed for the SA-1 tumor model, where tumor growth delay was 31 days and 62% of the animals were free of tumor 100 days after the treatment. Side-effects of electrochemotherapy were demonstrated by body weight loss of the treated animals as well as some animal mortality recorded up to 7 days after the treatment, especially in the animals where tumors were located close to the spine. Our results are in accordance with previous results, and prove that use of high voltage electric pulses is promising for potentiation of BLM anti-tumor effectiveness.