Electrochemotherapy against colorectal carcinoma: comparison of in vitro cytotoxicity of 5-fluorouracil, cisplatin and bleomycin.

Effectiveness of electrochemotherapy against colorectal carcinoma (CRC) was investigated in vitro using murine CRC cell lines. Electropermeabilization did not increase the sensitivity of CRC cells to 5-fluorouracil or cisplatin. Conversely, electropermeabilization markedly increased the sensitivity of CRC cells to bleomycin (BLM), resulting in 1,000-fold higher susceptibility. Subsequent analyses revealed that electropermeabilization significantly increased intracellular BLM levels of CRC cells. These results suggest that electrochemotherapy with BLM is a promising modality for the treatment of CRC, and that electrochemotherapy can be translated from the treatment of superficial tumors to the treatment of internal tumors including CRC.