References of "Lair, Florence"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPreconditioning of the Tumor Vasculature and Tumor Cells by Intermittent Hypoxia: Implications for Anticancer Therapies
Martinive, Philippe ULg; DEFRESNE, Florence; BOUZIN, Caroline et al

in Cancer Research (2006), 66(24), 11736-44

Hypoxia is a common feature in tumors associated with an increased resistance of tumor cells to therapies. In addition to O2 diffusion–limited hypoxia, another form of tumor hypoxia characterized by ... [more ▼]

Hypoxia is a common feature in tumors associated with an increased resistance of tumor cells to therapies. In addition to O2 diffusion–limited hypoxia, another form of tumor hypoxia characterized by fluctuating changes in pO2 within the disorganized tumor vascular network is described. Here, we postulated that this form of intermittent hypoxia promotes endothelial cell survival, thereby extending the concept of hypoxia-driven resistance to the tumor vasculature. We found that endothelial cell exposure to cycles of hypoxia reoxygenation not only rendered them resistant to proapoptotic stresses, including serum deprivation and radiotherapy, but also increased their capacity to migrate and organize in tubes. By contrast, prolonged hypoxia failed to exert protective effects and even seemed deleterious when combined with radiotherapy. The use of hypoxia-inducible factor-1α (HIF-1α)–targeting small interfering RNA led us to document that the accumulation of HIF-1α during intermittent hypoxia accounted for the higher resistance of endothelial cells. We also used an in vivo approach to enforce intermittent hypoxia in tumor-bearing mice and found that it was associated with less radiation-induced apoptosis within both the vascular and the tumor cell compartments (versus normoxia or prolonged hypoxia). Radioresistance was further ascertained by an increased rate of tumor regrowth in irradiated mice preexposed to intermittent hypoxia and confirmed in vitro using distinctly radiosensitive tumor cell lines. In conclusion, we have documented that intermittent hypoxia may condition endothelial cells and tumor cells in such a way that they are more resistant to apoptosis and more prone to participate in tumor progression. Our observations also underscore the potential of drugs targeting HIF-1α to resensitize the tumor vasculature to anticancer treatments. (Cancer Res 2006; 66(24): 11736-44) [less ▲]

Detailed reference viewed: 20 (2 ULg)
Full Text
Peer Reviewed
See detailProlactin/growth hormone-derived antiangiogenic peptides highlight a potential role of tilted peptides in angiogenesis
Nguyen, Ngoc-Quynh-Nhu ULg; Tabruyn, Sébastien ULg; Lins, Laurence ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2006), 103(39), 14319-14324

Angiogenesis is a crucial step in many pathologies, including tumor growth and metastasis. Here, we show that tilted peptides exert antiangiogenic activity. Tilted (or oblique-oriented) peptides are short ... [more ▼]

Angiogenesis is a crucial step in many pathologies, including tumor growth and metastasis. Here, we show that tilted peptides exert antiangiogenic activity. Tilted (or oblique-oriented) peptides are short peptides known to destabilize membranes and lipid cores and characterized by an asymmetric distribution of hydrophobic residues along the axis when helical. We have previously shown that 16-kDa fragments of the human prolactin/growth hormone (PRL/GH) family members are potent angiogenesis inhibitors. Here, we demonstrate that all these fragments possess a 14-aa sequence having the characteristics of a tilted peptide. The tilted peptides of human prolactin and human growth hormone induce endothelial cell apoptosis, inhibit endothelial cell proliferation, and inhibit capillary formation both in vitro and in vivo. These antiangiogenic effects are abolished when the peptides' hydrophobicity gradient is altered by mutation. We further demonstrate that the well known tilted peptides of simian immunodeficiency virus gp32 and Alzheimer's beta-amyloid peptide are also angiogenesis inhibitors. Taken together, these results point to a potential new role for tilted peptides in regulating angiogenesis. [less ▲]

Detailed reference viewed: 102 (23 ULg)
Full Text
Peer Reviewed
See detailGSK3-Mediated BCL-3 phosphorylation modulates its degradation and its oncogenicity
Viatour, Patrick ULg; Dejardin, Emmanuel ULg; Warnier, Michael et al

in Molecular Cell (2004), 16(1), 35-45

The oncoprotein BCL-3 is a nuclear transcription factor that activates NF-kappaB target genes through formation of heterocomplexes with p50 or p52. BCL-3 is phosphorylated in vivo, but specific BCL-3 ... [more ▼]

The oncoprotein BCL-3 is a nuclear transcription factor that activates NF-kappaB target genes through formation of heterocomplexes with p50 or p52. BCL-3 is phosphorylated in vivo, but specific BCL-3 kinases have not been identified so far. In this report, we show that BCL-3 is a substrate for the protein kinase GSK3 and that GSK3-mediated BCL-3 phosphorylation, which is inhibited by Akt activation, targets its degradation through the proteasome pathway. This phosphorylation modulates its association with HDAC1, -3, and -6 and attenuates its oncogenicity by selectively controlling the expression of a subset of newly identified target genes such as SLPI and CxcI1. Our results therefore suggest that constitutive BCL-3 phosphorylation by GSK3 regulates BCL-3 turnover and transcriptional activity. [less ▲]

Detailed reference viewed: 36 (11 ULg)