Modification of membrane fluidity and depolarization by some anthracyclines in different cell lines

One of the major problems in cancer treatment is the progressive desensitiz ation of cancer cells to chemotherapeutic drugs. Several hypotheses have be en advanced to explain this property of cancer cells. In recent years diffe rent calcium channel blockers and other chemosensitizing agents like synthe tic progestins have been used to revert drug resistance. In our experiments we evaluated the effects of Doxorubicin and Idarubicin on membrane fluidit y and depolarization using normal lymphocytes, chronic lymphatic leukemia l ymphocytes, normal breast and hormone dependent breast cancer cells and car diomyocytes. The drugs were used alone or in combination with Verapamil and Medroxyprogesterone acetate. We showed that MPA enhances DOXO and IDA bioc hemical effects, acting nor only on the membrane lipid bilayer, but also on ion channels. VERA instead does not seem to act through the same mechanism .