[The expression of glutathione s-transferase in leukemic cells and resistance to chemotherapy].

ABSTRACT

In order to study the relationship between the expression of glutathione S-transferase (GST) in leukemic cells and the chemoresistance in patients with acute leukemia, the expressions of GST activity and GST mRNA were measured according to spectrophotometric assay based on the use of 1-choloro-2, 4-dinitro benzene and in situ hybridization. The results were studied in correlation with some clinical and pathological data. Results showed that 1. There is no significant differences between activities of the enzyme with the different leukemia types according to the FAB classification. 2. GST activity and GST mRNA expression in the patients, both untreated and relapse, were (4.5 +/- 1.0) U, 33.3% and (7.9 +/- 15) U, 66.3% respectively. 3. In 56 patients, GST activity was 1.7 +/- 0.7, 5.9 +/- 2.0 and 9.3 +/- 1.7 U and GST mRNA expression was 13.3%, 29.7% and 76.6%, respectively, in CR, PR and NR groups. The lowest values of GST activity and GST mRNA expression were observed in those patients who achieved complete remission. The highest values of GST activity and GST mRNA expression were observed in those patients with no response to treatment. It was concluded that the expression of GST in patients with acute leukemia is closely related to the chemosensitivities clinically. Determinations of GST activity and GST mRNA are useful for predicting the chemosensitivities and the prognosis of the disease.