Persian shallot, <Emphasis Type="Italic">Allium hirtifolium</Emphasis> Boiss,induced apoptosis in human hepatocellular carcinoma cells

This study investigated the potential of Persian shallot extract as an anticancer agent in HepG2 tumor cell line, an in vitro human hepatoma cancer model system. The inhibitory effect of Persian shallot on the growth of HepG2 cells was measured by MTT assay. To explore the underlying mechanism of cell growth inhibition of Persian shallot, the activity of Persian shallot in inducing apoptosis was investigated through the detection of annexin V signal by flow cytometry and expression of some apoptosis related genes such p21, p53, puma, caspase-8 family-Bcl-2 proteins like bid, bim, bcl-2 and bax were measured by real-time PCR in HepG2 cells. Persian shallot extract inhibited the growth of HepG2 cells in a dose-dependent manner. The IC₅₀ value (inhibiting cell growth by 50%) was 149 μg/ml. The results of real-time PCR revealed a significant up-regulation of bid, bim, caspase-8, puma, p53, p21 and bax genes and a significant downregulation of bcl-2 gene in HepG2 cells treated with Persian shallot extract significantly. Therefore, this is the first report on an increased expression of bid, bim, caspase-8, puma, p53, p21 and bax genes and down regulation of bcl-2 gene indicating that the Persian shallot extract possibly induced the process of cell death through the intrinsic and extrinsic apoptosis pathways and triggers the programmed cell death in HepG2 tumor cell lines by modulating the expression of pro-/anti-apoptotic genes. Furthermore, we showed that Persian shallot extract increased annexin V signal and expression, resulting in apoptotic cell death of HepG2 cells after 24 h treatment. Therefore, according to the results of this study, the Persian shallot extract could be considered as a potential candidate for production of drug for the prevention or treatment of human hepatoma.     

Transient formation of DNA strand breaks during the induced differentiation of a human promyelocytic leukaemic cell line, HL-60.

During the induced differentiation of the human promyelocytic leukaemic cell line, HL-60, along the myelocytic lineage, DNA strand-breaks are formed. These breaks which are formed in the face of a proficient DNA repair mechanism, are only transiently maintained and subsequently become religated. The ligation of these breaks requires the activity of the nuclear adenosine diphosphoribosyl transferase (ADPRT). Inhibition of nuclear ADPRT, an enzyme totally dependent on the presence of DNA strand-breaks for its activity and required for efficient DNA repair in eukaryotic cells, blocks the religation of these breaks but not their formation. The inhibition of DNA strand ligation in the differentiating HL-60 cells results in loss of viability and cell death.     

The activity and properties of poly(adenosine diphosphate ribose) polymerase in vitro during the embryonic development of the South African clawed toad Xenopus laevis

Characterization of poly(ADPribose) polymerase in isolated nuclei of Xenopus laevis embryos shows that maximum activity in vitro occurs at 25°C in 10 mM Tris-HCl buffer, pH 8.0, containing 20 mM MgCl₂, 1 mM dithiothreitol, and 3 mM NaF. Under these conditions the apparent K_m for NAD⁺ was 0.125 mM. The activity of the polymerase during embryogenesis was measured using both a whole embryo extract and isolated embryonic nuclei. Both of these sources of enzyme demonstrated an increase of approximately eightfold in the activity per cell, between early cleavage (stages 2–4; Nieuwkoop and Faber, 1956, “Normal Table of Xenopus laevis (Daudin),” North-Holland, Amsterdam) and late neurula (stages 23–24). From late neurula to early tadpole (stages 38–39) the activity of the extracted enzyme, calculated per cell, decreased by 64%. During the same period the activity of the enzyme in isolated nuclei increased by 40% to reach its maximum activity in early tail bud (stages 27–28), and thereafter decreased by 23%. These results indicate a possible involvement of poly(ADPribose) polymerase in these embryos in the cell differentiation processes, rather than in cell proliferation.     

Growth Performance,Hemato-Immunological Responses,and Digestive Enzyme Activities in Silvery-Black Porgy (<Emphasis Type="Italic">Sparidentex hasta</Emphasis>) Fed Dietary Bovine Lactoferrin

An 8-week study was conducted to evaluate three different diets supplemented with bovine lactoferrin (LF) at 0 (control), 800, and 1200 mg LF kg^?1 diet on somatic growth, hemato-immunological parameters, antioxidant status, and digestive enzyme activities in silvery-black porgy (Sparidentex hasta) juveniles. Fish fed the 800 mg LF kg^?1 diet had higher growth performance and feed utilization parameters than the other groups. Hematological and liver antioxidant parameters were not affected by dietary LF supplementation. Fish fed the 800 mg LF kg^?1 diet had higher plasma lysozyme activity values than the other groups. Total protease activity was higher in fish fed LF-supplemented diets than the control group. Results indicated that diet supplemented with 800 mg kg^?1 for 8 weeks enhanced somatic growth performance, lysozyme activity, and proteolytic digestive enzyme activities in S. hasta, as well as improving feed efficiency parameters like the protein efficiency and feed conversion ratios.     

Human and Murine High Endothelial Venule Cells Phagocytose Apoptotic Leukocytes

Apoptotic cell death occurs during normal lymphocyte development and differentiation as well as following lymphocyte exposure to endogenous corticosteroids released during stress, malnutrition, and trauma. Recognition and engulfment of these apoptotic cells is important for the clearance of dying cells before they release potent inflammatory mediators into the vasculature or tissues. Phagocytosis of apoptotic cells is accomplished in part by macrophages. We report for the first time that apoptotic lymphocytes are also phagocytosed by high endothelial venule (HEV) cells. The murine HEV cell line mHEVa rapidly phagocytosed apoptotic lymphoid and myeloid cells with the greatest rate of phagocytosis occurring at 0–6 h. To confirm HEV cell interaction with apoptotic cells, we demonstrated that apoptotic human tonsil lymphocytes were phagocytosed by human tonsil HEV cells in primary cultures. Furthermore, we examined HEV cell phagocytosisin vivo.Mice were treated with a natural corticosterone (4-pregnene-11β,21-diol-3,20-dione) at levels detected during stress or malnutrition (93–180 μg serum cortisol/dl). At 4–12 h posttreatment, apoptotic lymphocytes were present inside vacuoles of HEV cells in axillary lymph node tissue sections, as determined by transmission electron microscopy. These data suggest that, in addition to macrophages, lymph node HEV cells also play a role in the removal of apoptotic lymphocytes. Moreover, since HEV cells are specialized endothelial cells that regulate lymphocyte migration into peripheral lymphoid tissues, they may provide an important checkpoint for clearance of apoptotic lymphocytes within the vasculature, as well as limiting entrance of nonfunctional lymphocytes into the lymph node.