Mice hypomorphic for PREP1 exhibit defects in T-cell development, with a decreased number of single-positive thymocytes, increased apoptosis of double-positive thymocytes, and abnormalities in the expression
of αβ and γδ T-cell receptors [19]. Additionally, reduction in PREP1 expression directly affects the expression of MEIS and PBX and consequently, normal embryonic hematopoiesis [20]. In summary, TALE genes codify for important transcription factors involved in hematopoiesis and leukemogenesis and are important survival, BIIB057 nmr differentiation, and apoptosis pathway modulators in hematopoietic cells. In this study, we analyzed the expression of TALE genes in leukemia-derived cell lines, in samples of KU55933 mw patients with Acute lymphoblastic leukemia
(ALL), and in samples of clinically healthy donors. We observed consistent up-regulation of MEIS1 and PREP1 and down-regulation of PBX4 selleck chemical in leukemic cell lines and in the samples of patients with ALL. Interestingly, RNA-mediated down-modulation of MEIS1 lowers leukemic cell proliferation. Additionally, chemotherapeutic treatment of lymphoblastic cell lines induces an increment in PREP1, PBX2, and PBX4 messenger RNA (mRNA) levels that could be related with a more resistant phenotype. Results Higher Expression Levels of MEIS1, MEIS2, and PREP1 Genes in Leukemia-derived Cell Lines selleck chemicals llc Compared with Normal Cells TALE genes are normally involved in the differentiation of hematopoietic cells and their
expression has been related with deregulated differentiation. From this starting point, we wanted to determine the expression levels of TALE genes in cells with impaired differentiation. For this purpose, we choose leukemic-derived cell lines and normal differentiated cells as the study model. In order to analyze the expression of TALE genes, we first selected primer pairs to amplify these genes and proved these primers by conventional PCR reactions utilizing a pull of complementary DNA (cDNA) obtained from leukemia-derived cell lines (Table 1). All primer pairs were able to amplify a specific product corresponding to the expected size for each TALE gene (Figure 1A); however, for PBX1, we observed an additional band of lower molecular size. We carried out the same approach to analyze primer pairs designed to amplify the L32 ribosomal protein (RPL32) and Beta-Actin (ACTB) in order to have reference genes to measure relative gene expression (Figure 1A). Regarding PBX1, we also noticed the low-molecular-weight band existing in controls and in all leukemia derived cell lines (Figure 1B). By sequence analysis, we found that this corresponds to an isoform of PBX1 in which exon 7 is lost (Figures 1B and 1C). This indicated that our PCR primers were specific for PBX1, and also that they are able to amplify both PBX1 versions.