The rate of apoptosis and expression of Bcl-2 and Bax in leukocytes of acute myeloblastic leukemia patients
Abstract:
The rate of apoptosis as well as expression of Bcl-2 and Bax was evaluated before and after induction therapy in leukocytes of 70 patients with acute myeloblastic leukemia (AML), retrospectively divided into group A (with longer survival) and group B (with shorter survival). We found, that leukocytes of untreated AML patients showed susceptibility to apoptosis similar to control cells. Marked increase in percentage of apoptotic leukocytes was observed after induction therapy exclusively in patients with longer survival, which was accompanied by better normalization of routine hematological parameters. In this group, the Bcl-2/Bax ratio was similar to the control and remained unchanged after treatment. In AML patients with shorter survival, a twofold increase in this ratio was observed both before and after the completion of induction therapy. In both groups of untreated patients, western blot analysis revealed the presence of prominent additional bands reacting with anti-Bcl-2 or anti-Bax antibody, which were undetectable in control leukocytes. After the therapy, these bands disappeared, especially in patients from group A. In conclusion, the lack of therapy-induced enhancement in leukocyte apoptosis, an increased ratio of Bcl-2/Bax as well as persistent presence of abnormal Bcl-2 and Bax protein bands after induction therapy in AML patients may be considered as factors associated with unfavorable clinical outcome