Anti-Cancer, anti-Necrotic and Imaging TumorMarker role of a novel form of ManganeseSuperoxide Dismutase and its leader peptide

The manganese superoxide dismutase (MnSOD) isolated from a human liposarcoma cell line (LSA) was able to kill cancer cells expressing oestrogen receptors, while it did not have cytotoxic effects on normal cells. The oncotoxic activity of the recombinant MnSOD (rMnSOD) was due, likely, to an increase in the level of oxidants in the tumor cells, which have low levels of catalase and, consequently, reach the threshold of toxicity before normal cells. The effectiveness of the rMnSOD in repairing the damage caused by radical excess was further shown by its topical application on necrotic skin. Together with its oncotoxic activity, the rMnSOD exerts a radioprotective effect on normal cells irradiated with X rays. The rMnSOD is characterized by the presence of a leader peptide, which allows the protein to enter cells: this unique property can be used in the radiodiagnosis of cancer or chemotherapy, conjugating radioactive substances or chemotherapic drugs to the leader peptide of the MnSOD. Compared to traditional chemotherapic agents, the drugs conjugated with the leader peptide of MnSOD can selectively reach and enter only the cancer cells, thus reducing the side effects of the traditional treatments.