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Although the response rates of chemotherapy in patients with acute T-lymphoblastic leukemia (T-ALL) have improved significantly, the outcome of these patients is still poor. Previous studies suggested that baicalein could inhibit the growth of several cancers, while its effect on T-ALL cells remains unclear. We used Jurkat cells as an in vitro model of T-ALL. Cell counting kit-8 assay and cytometric analysis with Annexin V-FITC/PI double staining were used to investigate the proliferation and apoptosis of Jurkat cells treated with increasing concentration of baicalein for indicated time. RT-PCR and western blotting was used to test the expression of Wnt/β-catenin associated genes and proteins. In cell viability assay, baicalein could inhibit the proliferation of Jurkat cells both in dose- and time-dependent manners. In cell apoptosis assay, baicalein could stimulate apoptosis of Jurkat cells both in dose- and time-dependent manners. Moreover, we demonstrated that baicalein could down-regulated the mRNA and protein levels of β-catenin and its widely accepted downstream targets (c-Myc, cyclin D1, and Axin2) in dose-dependent manners. These results proved that baicalein might be a potential choice for the treatment of T-ALL. [ABSTRACT FROM AUTHOR]

Introduction: Altered gene expression coincides with leukemia development and may affect distinct features of leukemic cells. PITHD1 was significantly downregulated in leukemia and upregulated upon PMA induction in K562 cells undergoing megakaryocyte differentiation. We aimed to study the function of PITHD1 in megakaryocyte differentiation. Materials and methods: K562 cells and fetal liver cells were used for either overexpression or downregulation of PITHD1 by retroviral or lentiviral transduction. FACS was used to detect the expression of CD41 and CD42 to measure megakaryocyte differentiation in these cells. Western blot and quantitative RT-PCR were used to measure gene expression. Dual luciferase assay was used to detect promoter or internal ribosomal entry site (IRES) activity. Results: Ectopic expression of PITHD1 promoted megakaryocyte differentiation and increased RUNX1 expression while PITHD1 knockdown showed an opposite phenotype. Furthermore, PITHD1 efficiently induced endogenous RUNX1 expression and restored megakaryocyte differentiation suppressed by a dominant negative form of RUNX1. PITHD1 regulated RUNX1 expression at least through two distinct mechanisms: increasing transcription activity of proximal promoter and enhancing translation activity of an IRES element in exon 3. Finally, we confirmed the function of PITHD1 in regulating RUNX1 expression and megakaryopoiesis in mouse fetal liver cells. Conclusion and significance: PITHD1 was a novel activator of IRES and enhanced RUNX1 expression that subsequently promoted megakaryocyte differentiation. Our findings shed light on understanding the mechanisms underlying megakaryopoiesis or leukemogenesis. [ABSTRACT FROM AUTHOR]

Human primary myeloma cells are well known to be heterogeneous with regard to morphology and surface phenotype. We confirmed the heterogeneous expression of such multilineage markers as CD33, CD7, CD56, CD4, and CD86 in primary myeloma cells from 20 patients with multiple myeloma and in 8 human myeloma cell lines. CD33 expression in the Liu01 cell line, a subclone of U266 cells, and in vitamin D3-treated ILKM3 cells, correlated with a monocytoid morphology featuring convoluted nuclei and with increased C/EBPalpha expression. CD56+ myeloma cells from some myeloma patients and the CD56+ (but not the CD56-) myeloma cell lines expressed neuronal cell markers, such as neuron-specific enolase and beta-tubulin III. CD7 expression in Liu01 cells and forskolin-stimulated U266 cells coincided with the presence of large cytoplasmic granules, and these cells featured increased expression of perforin messenger RNA and significant natural killer cell activity. Interleukin 6 (IL-6), a growth factor for myeloma cells, down-regulated CD33, CD7, or CD56 expression in primary myeloma cells, as well as in Liu01 cells. Therefore, these data suggest that human myeloma cells are capable of inducing the expression of multilineage markers and that IL-6 can down-regulate such expression. [ABSTRACT FROM AUTHOR]

Human myeloma cells are heterogenous morphologically and phenotypically. Myeloma cells can be classified into at least 5 subpopulations; MPC-1-CD45+CD49e-, MPC-1-CD45-CD49e- immature myeloma cells, MPC-1+CD45-CD49e-, MPC-1+CD45+CD49e- intermediate myeloma cells and MPC-1+CD45+CD49e+ mature myeloma cells. Interleukin-6(IL-6) is a major growth factor for human myeloma cells, but only MPC-1-CD45+CD49e- immature myeloma cells can response directly to IL-6 to proliferate. In the U-266 cell lines, IL-6 can lead to the induction of CD45 expression and CD45+ U-266 cells can proliferate in response to IL-6. In primary myeloma cells, MPC-1-CD45-CD49e- immature myeloma cells sorted from bone marrow samples can be changed to CD45+ cells by addition of IL-6 in vitro. In both CD45- and CD45+ U-266 cells, STAT3 and MAPK(ERK1/2) can be activated in response to IL-6 equally between them, but src family kinases such as Lyn, Fyn can be activated only in CD45+ U-266 cells. Thus, the activation of the src family kinases associated with CD45 expression is a prerequisite for the proliferation of myeloma cells. In the bone marrow of myeloma patients, most myeloma cells do not express CD45, and CD45+ immature myeloma cells are only 1 approximately 2%. In order to clarify the difference of cellular context between CD45- and CD45+ myeloma cells, PCR-based cDNA subtraction was performed from CD45+ U-266 cells to CD45-U-266 cells. The series of this subtraction selected several genes. Furthermore, sensitivity to stress stimuli between CD45+ and CD45- U-266 cells was also compared. CD45-U-266 cells were markedly more resistant to stress conditions such as serum-free condition. Therefore, we can speculate that in the bone marrow of human myelomas IL-6 can induce proliferation of CD45+ immature cells, but the amount of IL-6 is too low to support CD45+ myeloma cells and loss of CD45 results in no direct response to IL-6 to proliferate but confers resistance to stress condition leading to the longer survival at the limited amount of IL-6. [ABSTRACT FROM AUTHOR]

Drug-induced immune hemolytic anemia (DIIHA) is a relatively uncommon condition characterized by a sudden drop in hemoglobin, putatively following exposure to drugs. Severe forms of hemolysis characterized by rapidly falling hemoglobin levels and hemoglobinuria are extremely rare. Here we report the case of a patient who exhibited severe DIIHA due to puerarin. Direct antiglobulin testing and drug-dependent antibody testing indicated that the antibodies were drug-dependent and reacted only with RBCs in the presence of the drug. Puerarin is the major isoflavonoid derived from the Chinese medical herb Radix puerariae, and has not yet been widely reported as associated with DIIHA. These results suggest that puerarin may be a cause of severe hemolysis and should be used with caution. [ABSTRACT FROM AUTHOR]