Cell death induced by tamoxifen in human blood lymphocytes cultivated in vitro

Many chemotherapeutic agents with a potential against solid tumors or leukemia can cause lymphopenia. Tamoxifen (TAM) is a synthetic non-steroidal anti-estrogen drug employed in female breast cancer treatment. The present study investigated the capacity of TAM to induce cell death in human lymphocytes cultivated in vitro. Lymphocytes were obtained from young (25-30 years; n = 3) and elderly women (58-77 years; n = 3) and cultivated for 24 or 48h, with or without TAM (20 μM). After the culture, cell viability, immunocytochemical response and ultrastructure were evaluated. TAM affected lymphocytes in a timedependent manner, and cells obtained from elderly women were the most sensitive to TAM. Immunocytochemical analysis evidenced higher frequency of apoptosis in treated cells, and the ultrastructural study revealed autophagic vacuoles, differing from the controls. In summary, the treated lymphocytes were affected by TAM, leading to cell death by apoptosis and autophagy.