Expression of SODD and P65 in ALL of children and its relationship with chemotherapeutic drugs.
ABSTRACT The expression of silence of death domains (SODD) and its clinical significance and relationship with phospho-NF-kappaB-p65 proteins in bone marrow cells of childhood acute lymphoblastic leukaemia (ALL) were explored, and the expression of SODD and phospho-NF-kappaB-p65 in Jurkat cells treated with chemotherapeutic drugs was detected in order to find a new chemotherapeutic target. The expression of SODD and phospho-NF-kappaB-p65 proteins in bone marrow cells was detected by immunohistochemistry in 25 children with ALL. The apoptosis rate was measured by Annexin-V-Fluorescence/PI double-labeling flow cytometry and the expression of SODD and phospho-NF-kappaB-p65 proteins determined by Western blotting in the Jurkat cells. It was found that the expression of SODD and active P65 in ALL was significantly higher than that in normal control group (P<0.05). The expression of the SODD and phospho-NF-kappaB-p65 proteins in the high-risk (HR) group was significantly higher than that in the standard-risk (SR) group (P<0.05). The Pearson rank correlation analysis revealed that there was a positive correlation between SODD and phospho-NF-kappaB-p65 expression (P<0.01, r=0.69). VCR could effectively induce the apoptosis of Jurkat cells, and down-regulate the expression of SODD and phospho-NF-kappaB-p65 proteins in a time-dependent manner, but DNR could not down-regulate the expression of SODD effectively. It was concluded that SODD may be closely related to the clinical classification and prognosis of ALL in children. The expression of SODD and phospho-NF-kappaB-p65 had a definite synergistic relationship with the onset and development of ALL. VCR could down-regulate the expression of SODD and inhibit the NF-kappaB activation, which could recover the sensibility of apoptosis in leukemic cells.
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ABSTRACT: Phosphoinositide 3-kinase (PI3K) regulates cell polarity and migration by generating phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P(3)) at the leading edge of migrating cells. The serine-threonine protein kinase Akt binds to PI(3,4,5)P(3), resulting in its activation. Active Akt promotes spatially regulated actin cytoskeletal remodeling and thereby directed cell migration. The inositol polyphosphate 5-phosphatases (5-ptases) degrade PI(3,4,5)P(3) to form PI(3,4)P(2), which leads to diminished Akt activation. Several 5-ptases, including SKIP and SHIP2, inhibit actin cytoskeletal reorganization by opposing PI3K/Akt signaling. In this current study, we identify a molecular co-chaperone termed silencer of death domains (SODD/BAG4) that forms a complex with several 5-ptase family members, including SKIP, SHIP1, and SHIP2. The interaction between SODD and SKIP exerts an inhibitory effect on SKIP PI(3,4,5)P(3) 5-ptase catalytic activity and consequently enhances the recruitment of PI(3,4,5)P(3)-effectors to the plasma membrane. In contrast, SODD(-/-) mouse embryonic fibroblasts exhibit reduced Akt-Ser(473) and -Thr(308) phosphorylation following EGF stimulation, associated with increased SKIP PI(3,4,5)P(3)-5-ptase activity. SODD(-/-) mouse embryonic fibroblasts exhibit decreased EGF-stimulated F-actin stress fibers, lamellipodia, and focal adhesion complexity, a phenotype that is rescued by the expression of constitutively active Akt1. Furthermore, reduced cell migration was observed in SODD(-/-) macrophages, which express the three 5-ptases shown to interact with SODD (SKIP, SHIP1, and SHIP2). Therefore, this study identifies SODD as a novel regulator of PI3K/Akt signaling to the actin cytoskeleton.Journal of Biological Chemistry 06/2011; 286(34):29758-70. · 4.65 Impact Factor
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ABSTRACT: Melanoma is an aggressive cancer that metastasizes rapidly and is refractory to conventional chemotherapies. Identifying microRNAs (miRNAs) that are responsible for this pathogenesis is therefore a promising means of developing new therapies. We identified miR-26a through microarray and quantitative reverse-transcription-PCR (qRT-PCR) experiments as an miRNA that is strongly downregulated in melanoma cell lines as compared with primary melanocytes. Treatment of cell lines with miR-26a mimic caused significant and rapid cell death compared with a negative control in most melanoma cell lines tested. In surveying targets of miR-26a, we found that protein levels of SMAD1 (mothers against decapentaplegic homolog 1) and BAG-4/SODD were strongly decreased in sensitive cells treated with miR-26a mimic as compared with the control. The luciferase reporter assays further demonstrated that miR-26a can repress gene expression through the binding site in the 3' untranslated region (3'UTR) of SODD (silencer of death domains). Knockdown of these proteins with small interfering RNA (siRNA) showed that SODD has an important role in protecting melanoma cells from apoptosis in most cell lines sensitive to miR-26a, whereas SMAD1 may have a minor role. Furthermore, transfecting cells with a miR-26a inhibitor increased SODD expression. Our findings indicate that miR-26a replacement is a potential therapeutic strategy for metastatic melanoma, and that SODD, in particular, is a potentially useful therapeutic target.Journal of Investigative Dermatology advance online publication, 29 November 2012; doi:10.1038/jid.2012.400.Journal of Investigative Dermatology 11/2012; · 6.19 Impact Factor