In vitro Evaluation of Cytarabin Induced Apoptosis in Leukemic Blasts

Apoptosis, or active cell death, is a specific mode of cell death, which is characterized by morphological changes such as chromatin condensation, fragmentation of the nucleus, cytoplasmic retraction and appearance of apoptotic bodies' containing apparently intact organelles. Apoptosis occurs in physiological conditions as a regulatory mechanism of tissue growth, where cell proliferation is balanced. The aim of this research was to study the ability of Fas to initiate apoptosis in vitro before and after treatment with Cytarabin on tissue culture and to correlate the response. The human leukemia and normal cells were treated with cytarabin in tissue culture, and apoptotic treated cells were estimated by flow cytometry and phosphatidylserines kit. The results were analyzed by statistical tests (post hoc). From these data, it was found that Fas antigen was expressed in all cases, but the expression level varied widely. Apoptosis and also Fas antigen expression in short term cell culture were higher in media containing drug than in media without drug; but there had been no reasonable correlation between percentage of Fas antigen and apoptosis responses before culture. Expression of Fas antigen was low in most of the leukemic cells and the preliminary results showed that increase in Fas antigen expression (above 20%) after treatment, was a favorable prognostic outcome. It is associated with increase relapse, free and total survival. In addition, using this antigen as a chemotherapic and immunotherapic target, would initiate a new strategy for treatment of leukemia (chemotherapy and immunotherapy).