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At the end of oogenesis, Xenopus laevis stage VI oocytes are arrested at the G2/M transition (prophase) waiting for progesterone to release the block and begin maturation. Progesterone triggers a cascade of phosphorylation events such as a decrease of pK(a) and an increase of maturating-promoting factor activity. Progression through meiosis was controlled(More)
The Aurora kinases are involved in the regulation of cell cycle progression, and alterations in their expression have been shown to associate with cell malignant transformation. In the present study, we demonstrated that human thyrocytes express all 3 Aurora kinases (A, B and C) at both protein and mRNA level and this expression is cell cycle-regulated. An(More)
Several N(1)-substituted polyamines containing various spacer units between nitrogen centers were synthesized as their respective HCl salts. The N(1)-substituents included benzyl, naphthalen-1-ylmethyl, anthracen-9-ylmethyl, and pyren-1-ylmethyl. The polyamine spacer units ranged from generic (4,4-triamine, 4,3-triamine, and diaminooctane) spacers to more(More)
Xenopus laevis Aurora-A is phosphorylated in vivo onto three amino acids: Ser53, Thr295 and Ser349. The activation of the kinase depends on its autophosphorylation on Thr295 within the T-loop. The phosphorylation of Ser53 by still unknown kinase(s) prevents its degradation. The present work focused on the regulation of Aurora-A function via Ser349(More)
The depsidone 9'-( O-methyl)protocetraric acid was isolated from the lichen Cladonia convoluta (Lam.) Anders along with the known (-)-usnic acid and fumarprotocetraric acid. The complete structure of 9'-( O-methyl)protocetraric acid was elucidated using HSQC and HMBC spectral data. (-)-Usnic acid was the only compound to display a moderate cytotoxic(More)
Anaplastic thyroid cancers (ATC) are aggressive tumors, which exhibit cell cycle misregulations leading to uncontrolled cellular proliferation and genomic instability. They fail to respond to chemotherapeutic agents and radiation therapy, and most patients die within a few months of diagnosis. In the present study, we evaluated the in vitro effects on ATC(More)
Polyamines (putrescine, spermidine, and spermine) are essential for growth and survival of all cells. When polyamine biosynthesis is inhibited, there is up-regulation of import. The mammalian polyamine transport system is unknown. We have previously shown that the heparan sulfate (HS) side chains of recycling glypican-1 (Gpc-1) can sequester spermine, that(More)
Netrin-1 was recently proposed to play an important role in embryonic and pathological angiogenesis. However, data reported led to the apparently contradictory conclusions that netrin-1 is either a pro- or an antiangiogenic factor. Here, we reconcile these opposing observations by demonstrating that netrin-1 acts as a survival factor for endothelial cells,(More)
A series of nine N(1)-(9-anthracenylmethyl)tetraamines (e.g., Ant-4,4,4-tetraamine) were synthesized and evaluated for cytotoxicity in L1210, alpha-difluoromethylornithine (DFMO)-treated L1210, Chinese hamster ovary (CHO), and CHO-MG cell lines. Surprisingly, the 3,3,4- and 3,4,3-tetraamine motifs had the same or decreased cytotoxicity in DFMO-treated L1210(More)
Polyamines are ubiquitous molecules, which, like iron, are essential for cell growth. All eukaryotic cells are equipped with a specific polyamine transport system (PTS). Polyamines have primary and secondary amino groups which chelate bivalent metal cations such as Fe and Cu. In the present study, we investigated the potential contribution of naturally(More)