| 1. |
- Aldonyte, R, et al.
(författare)
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Effects of major human antiprotease alpha-1-antitrypsin on the motility and proliferation of stromal cells from human exfoliated deciduous teeth
- 2010
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Ingår i: e-biomed. - : Future Medicine Ltd. - 1524-8909. ; 5:4, s. 633-643
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Intrinsic tissue regeneration mechanisms are still not fully understood. The destruction/reconstruction processes are usually in fine balance; however, this can be easily destroyed, for example in the environment of chronic inflammation. One of the major proteins present at the inflammatory sites is the multifunctional protein alpha-1-antitrypsin (AAT). In this study, potential therapeutic effects of this major human antiprotease on progenitor cells are assessed. MATERIALS & METHODS: Stromal cells from human exfoliated deciduous teeth (SHEDs) were used, which are similar to the mesenchymal stromal cells isolated from other tissues. SHEDs were cultivated in the presence of subphysiological, physiological and inflammatory concentrations of AAT, and their proliferation and motility traits were assayed. Some intracellular signaling pathways, AAT internalization by SHEDs and their matrix metalloprotease profile were studied in parallel. RESULTS: Physiologic and inflammatory concentrations of AAT significantly increased the cell proliferation rate, induced phosphorylation of several key protein kinases and increased the amount of secreted active gelatinases. Moreover, cells exposed to physiologic and inflammatory levels of AAT were able to invade and migrate more efficiently. Subphysiologic AAT levels did not change cell behavior significantly. CONCLUSION: AAT at physiologic and inflammatory concentrations positively modulates the proliferation and motility of SHEDs in vitro. These results suggest the importance of AAT in the maintenance and regulation of tissue progenitor cells in vivo.
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| 2. |
- Pivoriunas, A., et al.
(författare)
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PI 3-K signaling pathway suppresses PMA-induced expression of p21WAF1/ Cip1 in human leukemia cells
- 2007
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Ingår i: Molecular and Cellular Biochemistry. - : Springer Science and Business Media LLC. - 0300-8177 .- 1573-4919. ; 302:1-2
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Tidskriftsartikel (refereegranskat)abstract
- Despite the understanding of the importance of phosphoinositide 3-kinase (PI 3-K) signaling pathway in the regulation of cellular proliferation, little is known about its role during phorbol 12-myristate 13-acetate (PMA)-induced differentiation in human leukemia cells. Here, we report a novel finding that PI 3-K inhibition by LY294002 significantly increases p21WAF1/Cip1 expression in PMA-stimulated human leukemia cells NB4 and THP1. LY294002 potentiated expression of p21WAF1/Cip1 via a p53-independent mechanism and did not affect mitogen activated protein kinase (MAPK) activation. Electrophoretic mobility shift (EMSA) experiments revealed that blocking of PI 3-K was associated with increased binding of transcription factor Sp1 to the PMA-responsive sites on the p21WAF1/Cip1 promoter. Pretreatment with rapamycin, an inhibitor of mTOR kinase, decreased the expression of p21WAF1/Cip1 protein in PMA-stimulated NB4 cells. The level of PMA-induced p21WAF1/ Cip1 protein expression was lower in NB4 cells overexpressing wild type protein kinase C ? (PKC ?) compared to those transfected with empty vector or with kinase inactive PKC ?. Sp1 binding to the p21WAF1/Cip1 promoter was completely lost in a wild type PKC ? overexpressing and PMA-stimulated NB4 cells. We demonstrate that PI 3-K signaling pathway suppresses PMA-induced expression of p21WAF1/Cip1 in human leukemia cells, and that this effect is partly mediated by PKC ?. © Springer Science+Business Media, LLC 2007.
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| 3. |
- Savickiene, Jurate, et al.
(författare)
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Sp1 and NF-kappa B transcription factor activity in the regulation of the p21 and FasL promoters during promyelocytic leukemia cell monocytic differentiation and its associated apoptosis
- 2004
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1030, s. 569-577
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of human acute promyelocytic leukemia cells with phorbol 12-myristate 13-acetate (PMA) results in growth arrest and differentiation toward monocytes, which subsequently die by apoptosis. However, the relationship between terminal differentiation and apoptosis remains unclear. Here we have studied Sp1 and nuclear factor B-K (NF-B-K) transcription factor activity in controlling promoters of cell cycle-regulating (p21/WAF1/CIP1) and cell death (FasL) genes during monocytic differentiation and apoptosis of the human acute promyelocytic leukemia cell lines NB4 and HL-60. Using the electrophoretic mobility shift assay, we observed that PMA treatment of NB4 cells caused an early response in Sp1 binding to the p21 and FasL promoters at 8 h. The firmly adherent cell phenotype, characteristic of differentiated cells, retained Sp1-binding activity to either promoter, but it was often lost completely in detached, apoptotic cells. The association of Sp1 with the p21 promoter during monocytic differentiation correlated with the levels of expressed p21 in the cytoplasmic fraction, as detected by immunoblotting. In HL-60 cells, very weak or no Sp1 binding to either promoter was observed. Low NF-B-K affinity for its consensus sites and to the FasL promoter was characteristic of apoptotic cells. The results of this study suggest a positive role of Sp1 and NF-B-K, as regulators of p21 and FasL genes, in leukemic cell survival and monocytic differentiation and a negative role in apoptotic cell death.
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