Anti-H can trigger apoptosis and down-regulate FUT1 expression in erythroid differentiated K562 cells without complement mediation

An Active Compound from the Pyrazine Family Induces Apoptosis by Targeting the Bax/Bcl2 and Survivin Expression in Chronic Myeloid Leukemia K562 Cells

BACKGROUND

It has been established that pyrazine derivatives, which have widespread bioactivities, can effectively treat cancer.

OBJECTIVES

In this study, we investigated the effects of 2-methoxy-5-(oxiran-2-ylmethyl) phenyl pyrazine-2- carboxylate (2-mOPP), a new pyrazine derivative, on proliferation, viability, and apoptosis induction in human leukemia K562 cells.

METHODS

For this purpose, the K562 cells were treated with various concentrations (20-120 μM) of the 2-mOPP for 24-72 hours. Cell viability was determined by MTT growth inhibition assay. Apoptotic activity of 2-mOPP was investigated morphologically by Hoechst staining, cell surface expression assay of phosphatidylserine by Annexin-V/PI technique, as well as DNA fragmentation assay. The effect of 2-mOPP on the K562 cell cycle was studied by flow cytometry. To determine the impact of 2-mOPP on the expression of intrinsic apoptosis-related genes, Bcl2 (anti-apoptotic), Bax (pro-apoptotic), and Survivin genes expression levels were evaluated before and after treatment with 2-mOPP through Real-Time PCR analysis.

RESULTS

The results revealed that 2-mOPP inhibited viability with IC50 of 25μM in 72 h. Morphological changes assessment by fluorescence microscopy, Annexin V/PI double staining by flow cytometry, and DNA ladders formation upon cell treatment with the 2-mOPP showed that this compound induces apoptosis at IC50 value. Cell cycle arrest was observed in the G0/G1 phase, and the sub-G1 cell population (the sign of apoptosis) increased in a time-dependent manner. Low expression levels of Bcl2 and Survivin in K562 cells were observed 24-72 h after treatment. Along with the down-regulation of Survivin and Bcl2, the expression of Bax was increased after treatment with 2-mOPP.

CONCLUSION

These findings demonstrate that the new pyrazine derivative plays a crucial role in blocking the proliferation of the leukemic cells by inducing cell cycle arrest and apoptosis.

Spiroquinazolinone-induced cytotoxicity and apoptosis in K562 human leukemia cells: alteration in expression levels of Bcl-2 and Bax

Spiroquinazolinone compounds have been considered as a new series of potent apoptosis-inducing agents. In this study, anti-proliferative and apoptotic effects of the derivatives from the spiroquinazolinone family were investigated in the human chronic myeloid leukemia K562 cells. The K562 cells were treated with various concentrations of the spiroquinazolinone (10-300 µM) for 3 days and cell viability was determined by MTT growth inhibition assay. 4t-QTC was more active among these compounds with IC50 of 50 ± 3.6 µM and was selected for further studies. Apoptosis, as the mechanism of cell death was investigated morphologically by acridine orange/ethidium bromide (AO/EtBr) double staining, cell surface expression assay of phosphatidyl serine by Annexin V/PI technique, as well as the formation of DNA ladder. The K562 cells underwent apoptosis upon a single dose (at IC50 value) of the 4t-QTC compound, and over-expressed caspase-3 expression by more than 1.7-fold, following a 72 hr treatment. Furthermore, RT-PCR and Western blot analysis revealed that treatment of the K562 cells with 4t-QTC down-regulates and up-regulates the expression of Bcl-2 (anti-apoptotic) and Bax (pro-apoptotic), respectively. Based on the present data, it seems that these compounds from the spiroquinazolinone family are good candidates for further evaluation as an effective chemotherapeutic family acting through induction of apoptosis in chronic myeloid leukemia.

High-density genotyping of immune loci in Kawasaki disease and IVIG treatment response in European-American case-parent trio study

Kawasaki disease (KD) is a diffuse and acute small-vessel vasculitis observed in children, and has genetic and autoimmune components. We genotyped 112 case-parent trios of European decent (confirmed by ancestry informative markers) using the immunoChip array, and performed association analyses with susceptibility to KD and intravenous immunoglobulin (IVIG) non-response. KD susceptibility was assessed using the transmission disequilibrium test, whereas IVIG non-response was evaluated using multivariable logistic regression analysis. We replicated single-nucleotide polymorphisms (SNPs) in three gene regions (FCGR, CD40/CDH22 and HLA-DQB2/HLA-DOB) that have been previously associated with KD and provide support to other findings of several novel SNPs in genes with a potential pathway in KD pathogenesis. SNP rs838143 in the 3'-untranslated region of the FUT1 gene (2.7 × 10(-5)) and rs9847915 in the intergenic region of LOC730109 | BRD7P2 (6.81 × 10(-7)) were the top hits for KD susceptibility in additive and dominant models, respectively. The top hits for IVIG responsiveness were rs1200332 in the intergenic region of BAZ1A | C14orf19 (1.4 × 10(-4)) and rs4889606 in the intron of the STX1B gene (6.95 × 10(-5)) in additive and dominant models, respectively. Our study suggests that genes and biological pathways involved in autoimmune diseases have an important role in the pathogenesis of KD and IVIG response mechanism.