Cytotoxicity of different selective serotonin reuptake inhibitors (SSRIs) against cancer cells.

Cell membrane ion transporters expression and activity are altered in cancer cells and these phenotypic alterations offer potential targets for cancer therapies. Among the therapeutic agents affecting cell membrane transporters, serotonin reuptake inhibitors (SSRIs) have been shown to have anticancer potential. In this work, we have compared two SSRIs, one very specific for serotonin reuptake transporters (paroxetine) and another which also inhibit norepinephrine and dopamine transporters (venlafaxine), for their ability to counteract growth of various murine and human cancer cell lines. We found that paroxetine has cytotoxic activity against tumor cells, both of murine or human origin in the micromolar concentration range, whereas venlafaxine has not. A neurotransmitter receptor mediated mechanism of action appears thus unlikely for SSRIs cytotoxicity on cancer cells. With ranges of SSRIs cytotoxicity on cancer cells defined, limits in their possible applicability in cancer therapy is discussed.