Figure 5 Effect of MEIS1 expression on cell growth of leukemia-derived
cell lines. A) Expression levels of MEIS1 were analyzed by qRT-PCR in Jurkat, CEM, and K562 cells; expression of RPL32 was also determined and used as reference gene to calculate relative expression; B) Cell proliferation analysis of K562 and Jurkat cells; C, E) Expression levels of MEIS1 in Jurkat and K562 cell lines infected with virus carrying shRNA-E9 or shRNA-E13. Values were obtained by qRT-PCR using RPL32 as reference gene; D, F) Proliferation of MEIS1-silenced cells. Jurkat and K562 cells were infected with an shRNA directed to exon 9 GDC 941 (LVX-E9) and an shRNA directed to exon 13 (LVX-E13). Cell growth was determined counting the cells daily for 5 days. Graphics show means ± Standard deviations (SD) of values obtained from three independent experiments. Statistical differences were calculated at the end point of proliferation curves using 2 way ANOVA analysis and Bonferroni posttest, (*) significances are shown between groups www.selleckchem.com/products/ly3023414.html only when p ≤ 0.05. Expression of MEIS1 and PREP1 Is Modulated in Response to Apoptosis Induction by CHIR-99021 etoposide The other TALE member that we found up-regulated
in leukemic cells was PREP1. Expression of this gene has been associated with resistance to apoptosis and it also has been described that PREP1 regulates MEIS1 expression [20, 22]. In this respect, we subsequently analyzed whether the expression of PREP1 and MEIS1 was related with resistance to apoptosis induction by chemotherapeutic stimulus in leukemic cells. In order to assess
this parameter, cultured cells were exposed to etoposide for 1 or 2 h; thereafter, variations in MEIS1 and PREP1 expression were analyzed by qRT-PCR. We observed that after etoposide treatment, Jurkat cells exhibit a tendency to increase MEIS1 expression, CEM cells remained unchanged, while diminishes K562 expression was noteworthy (Figure 6A). For PREP1, nearly no difference Palmatine was observed in Jurkat cells; the response of CEM cells was more important because a notorious up-regulation was evidenced. Interestingly, K562 cells down-regulate PREP1 expression in response to etoposide (Figure 6A). To correlate these observations with phenotypic response, we measured the percentage of apoptotic cells after 5, 15, and 24 h of etoposide treatment. As can be observed in Figure 6B, Jurkat cells were the cells most sensitive to etoposide action; in contrast, CEM and K562 cells were the most resistant cells. Figure 6 Modulation of MEIS1 and PREP1 expression after etoposide treatment. A) Jurkat, CEM, and K562 cells were treated with 170 μM etoposide for 1 and 2 h; thereafter, total RNA was extracted and retrotranscribed. Real time-PCR assays were performed to determine the relative expression levels of MEIS1 and PREP1. Expression analysis was carried out by normalizing with non-treated cells and employing RPL32 as reference gene.