Abstract In view of obscure clinical and biological significance of leukemic cells heterogeneity, we studied the efficacy of apoptosis, proliferation, and expression levels of the Bcl-2, MDR1, LRP, and BCRP genes in sorted CD34+ and CD34- subpopulations of childhood AML leukemic samples. In five out of nine cases, CD34+ cells were less sensitive to spontaneous apoptosis and had from 1.2- to 5.0-fold higher expression levels of Bcl-2 (eight of ten) and from 1.5- to 28.7-fold higher expression levels of MDR1 (eight of ten). The expression levels of the LRP gene were from 1.1- to 1.8-fold higher in CD34+ subpopulations (five of ten cases), and the expression levels of the BCRP gene were from 1.1- to 22.4-fold higher in CD34+ leukemic cells (six of ten). In all M4 cases, the expression levels of LRP were higher in the CD34- subpopulation. Significant differences in the patterns of genes expression between patients do not allow us to conclude that the CD34+ fractions have more resistant phenotype than the CD34- subpopulations. Nevertheless, distinctions between CD34+ and CD34- cells may lead to different chemosensitivities between leukemic subpopulations in vivo and may determine the alteration of the leukemic immunophenotype during treatment and in relapse.
MDR1 modulates apoptosis in CD34+ leukemic cells
BUDA, GABRIELE;MAGGINI, VALENTINA;GALIMBERTI, SARA;BARALE, ROBERTO;ROSSI, ANNA MARIA;PETRINI, MARIO
2008-01-01
Abstract
Abstract In view of obscure clinical and biological significance of leukemic cells heterogeneity, we studied the efficacy of apoptosis, proliferation, and expression levels of the Bcl-2, MDR1, LRP, and BCRP genes in sorted CD34+ and CD34- subpopulations of childhood AML leukemic samples. In five out of nine cases, CD34+ cells were less sensitive to spontaneous apoptosis and had from 1.2- to 5.0-fold higher expression levels of Bcl-2 (eight of ten) and from 1.5- to 28.7-fold higher expression levels of MDR1 (eight of ten). The expression levels of the LRP gene were from 1.1- to 1.8-fold higher in CD34+ subpopulations (five of ten cases), and the expression levels of the BCRP gene were from 1.1- to 22.4-fold higher in CD34+ leukemic cells (six of ten). In all M4 cases, the expression levels of LRP were higher in the CD34- subpopulation. Significant differences in the patterns of genes expression between patients do not allow us to conclude that the CD34+ fractions have more resistant phenotype than the CD34- subpopulations. Nevertheless, distinctions between CD34+ and CD34- cells may lead to different chemosensitivities between leukemic subpopulations in vivo and may determine the alteration of the leukemic immunophenotype during treatment and in relapse.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
