19 research outputs found
The Hedgehog Receptor Patched Is Involved in Cholesterol Transport
International audienceBACKGROUND: Sonic hedgehog (Shh) signaling plays a crucial role in growth and patterning during embryonic development, and also in stem cell maintenance and tissue regeneration in adults. Aberrant Shh pathway activation is involved in the development of many tumors, and one of the most affected Shh signaling steps found in these tumors is the regulation of the signaling receptor Smoothened by the Shh receptor Patched. In the present work, we investigated Patched activity and the mechanism by which Patched inhibits Smoothened. METHODOLOGY/PRINCIPAL FINDINGS: Using the well-known Shh-responding cell line of mouse fibroblasts NIH 3T3, we first observed that enhancement of the intracellular cholesterol concentration induces Smoothened enrichment in the plasma membrane, which is a crucial step for the signaling activation. We found that binding of Shh protein to its receptor Patched, which involves Patched internalization, increases the intracellular concentration of cholesterol and decreases the efflux of a fluorescent cholesterol derivative (BODIPY-cholesterol) from these cells. Treatment of fibroblasts with cyclopamine, an antagonist of Shh signaling, inhibits Patched expression and reduces BODIPY-cholesterol efflux, while treatment with the Shh pathway agonist SAG enhances Patched protein expression and BODIPY-cholesterol efflux. We also show that over-expression of human Patched in the yeast S. cerevisiae results in a significant boost of BODIPY-cholesterol efflux. Furthermore, we demonstrate that purified Patched binds to cholesterol, and that the interaction of Shh with Patched inhibits the binding of Patched to cholesterol. CONCLUSION/SIGNIFICANCE: Our results suggest that Patched may contribute to cholesterol efflux from cells, and to modulation of the intracellular cholesterol concentration. This activity is likely responsible for the inhibition of the enrichment of Smoothened in the plasma membrane, which is an important step in Shh pathway activation
Combined administration of a small-molecule inhibitor of TRAF6 and Docetaxel reduces breast cancer skeletal metastasis and osteolysis:Running title : TRAF6/NFkB inhibition reduced breast cancer metastasis
Tumour necrosis factor receptor-associated factor 6 (TRAF6) has been implicated in breast cancer and osteoclastic bone destruction. Here, we report that 6877002, a verified small-molecule inhibitor of TRAF6, reduced metastasis, osteolysis and osteoclastogenesis in models of osteotropic human and mouse breast cancer. First, we observed that TRAF6 is highly expressed in osteotropic breast cancer cells and its level of expression was higher in patients with bone metastasis. Pre-exposure of osteoclasts and osteoblasts to non-cytotoxic concentrations of 6877002 inhibited cytokine-induced NF\u3baB activation and osteoclastogenesis, and reduced the ability of osteotropic human MDA-MB-231 and mouse 4T1 breast cancer cells to support bone cell activity. 6877002 inhibited human MDA-MB-231-induced osteolysis in the mouse calvaria organ system, and reduced soft tissue and bone metastases in immuno-competent mice following intra-cardiac injection of mouse 4T1-Luc2 cells. Of clinical relevance, combined administration of 6877002 with Docetaxel reduced metastasis and inhibited osteolytic bone damage in mice bearing 4T1-Luc2 cells. Thus, TRAF6 inhibitors such as 6877002 - alone or in combination with conventional chemotherapy - show promise for the treatment of metastatic breast cancer
A História da Alimentação: balizas historiogråficas
Os M. pretenderam traçar um quadro da HistĂłria da Alimentação, nĂŁo como um novo ramo epistemolĂłgico da disciplina, mas como um campo em desenvolvimento de prĂĄticas e atividades especializadas, incluindo pesquisa, formação, publicaçÔes, associaçÔes, encontros acadĂȘmicos, etc. Um breve relato das condiçÔes em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biolĂłgica, a econĂŽmica, a social, a cultural e a filosĂłfica!, assim como da identificação das contribuiçÔes mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histĂłrica, foi ela organizada segundo critĂ©rios morfolĂłgicos. A seguir, alguns tĂłpicos importantes mereceram tratamento Ă parte: a fome, o alimento e o domĂnio religioso, as descobertas europĂ©ias e a difusĂŁo mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rĂĄpido balanço crĂtico da historiografia brasileira sobre o tema
The hedgehog receptor patched functions in multidrug transport and chemotherapy resistance.
International audienceMost anticancer drugs fail to eradicate tumors, leading to the development of drug resistance and disease recurrence. The Hedgehog signaling plays a crucial role during embryonic development, but is also involved in cancer development, progression, and metastasis. The Hedgehog receptor Patched (Ptc) is a Hedgehog signaling target gene that is overexpressed in many cancer cells. Here, we show a link between Ptc and resistance to chemotherapy, and provide new insight into Ptc function. Ptc is cleared from the plasma membrane upon interaction with its ligand Hedgehog, or upon treatment of cells with the Hedgehog signaling antagonist cyclopamine. In both cases, after incubation of cells with doxorubicin, a chemotherapeutic agent that is used for the clinical management of recurrent cancers, we observed an inhibition of the efflux of doxorubicin from Hedgehog-responding fibroblasts, and an increase of doxorubicin accumulation in two different cancer cell lines that are known to express aberrant levels of Hedgehog signaling components. Using heterologous expression system, we stringently showed that the expression of human Ptc conferred resistance to growth inhibition by several drugs from which chemotherapeutic agents such as doxorubicin, methotrexate, temozolomide, and 5-fluorouracil. Resistance to doxorubicin correlated with Ptc function, as shown using mutations from Gorlin's syndrome patients in which the Ptc-mediated effect on Hedgehog signaling is lost. Our results show that Ptc is involved in drug efflux and multidrug resistance, and suggest that Ptc contributes to chemotherapy resistance of cancer cells. Mol Cancer Res; 10(11); 1496-508. ©2012 AACR
Crystallization and preliminary X-ray analysis of the human androgen receptor ligand-binding domain with a coactivator-like peptide and selective androgen receptor modulators
The Hedgehog Receptor Patched Functions in Multidrug Transport and Chemotherapy Resistance
Identification of small molecule inhibitors of RANKL and TNF signalling as anti-inflammatory and antiresorptive agents in mice
Portable, lĂ©ger, de lecture confortable, ressemblant au livre Ă s'y mĂ©prendre, la liseuse constituerait la solution de l'Ă©dition face Ă la rĂ©volution numĂ©rique. Et pourtant, le compte n'y est pas. Et si on essayait de penser l'avenir de l'Ă©dition Ă©lectronique sans se rĂ©fĂ©rer en permanence au bel objet qu'est le livre et aux nobles rayonnages des bibliothĂšques familiales ou des bibliothĂšques publiques ? Sur le fond, d'abord. Les liseuses sont vendues comme des livres Ă©lectroniques. De la mĂȘme ..
Endogenous Glutathione-Binding Proteins of Insect Cell Lines: Characterization and Removal from Glutathione S-Transferase (GST) Fusion Proteins
Functional studies of membrane-bound and purified human Hedgehog receptor Patched expressed in yeast
AbstractThe Sonic Hedgehog (Shh) signalling pathway plays an important role both in embryonic development and in adult stem cell function. Inappropriate regulation of this pathway is often due to dysfunction between two membrane receptors Patched (Ptc) and Smoothened (Smo), which lead to birth defects, cancer or neurodegenerative diseases. However, little is known about Ptc, the receptor of the Shh protein, and the way Ptc regulates Smo, the receptor responsible for the transduction of the signal. To develop structureâfunction studies of these receptors, we expressed human Ptc (hPtc) in the yeast Saccharomyces cerevisiae. We demonstrated that hPtc expressed in a yeast membrane fraction is able to interact with its purified ligand Shh, indicating that hPtc is produced in yeast in its native conformational state. Using Surface Plasmon Resonance technology, we showed that fluorinated surfactants preserve the ability of hPtc to interact with its ligand after purification. This is the first report on the heterologous expression and the purification of a native and stable conformation of the human receptor Ptc. This work will allow the scale-up of hPtc production enabling its biochemical characterization, allowing the development of new therapeutic approaches against diseases induced by Shh signalling dysfunction
Discovery of Diarylhydantoins as New Selective Androgen Receptor Modulators
A novel selective androgen receptor modulator scaffold
has been
discovered through structural modifications of hydantoin antiandrogens.
Several 4-(4-hydroxyphenyl)-<i>N</i>-arylhydantoins displayed
partial agonism with nanomolar in vitro potency in transactivation
experiments using androgen receptor (AR) transfected cells. In a standard
castrated male rat model, several compounds showed good anabolic activity
on levator ani muscle, dissociated from the androgenic activity on
ventral prostate, after oral dosing at 30 mg/kg. (+)-4-[3,4-Dimethyl-2,5-dioxo-4-(4-hydroxyphenyl)Âimidazolidin-1-yl]-2-(trifluoromethyl)Âbenzonitrile
((+)-<b>11b</b>) displayed anabolic potency with a strong dissociation
between levator ani muscle and ventral prostate (<i>A</i><sub>50</sub> = 0.5 mg/kg vs 70 mg/kg). The binding modes of two
compounds, including (+)-<b>11b</b>, within the AR ligand-binding
domain have been studied by cocrystallization experiments using a
coactivator-like peptide. Both compounds bound to the same site, and
the overall structures of the AR were very similar