Hedgehog pathway responsiveness correlates with the presence of primary cilia on prostate stromal cells

<p>Abstract</p> <p>Background</p> <p>Hedgehog (Hh) signaling from the urogenital sinus (UGS) epithelium to the surrounding mesenchyme plays a critical role in regulating ductal formation and growth during prostate development. The primary cilium, a feature of most interphase vertebrate cell types, serves as a required localization domain for Hh signaling transducing proteins.</p> <p>Results</p> <p>Immunostaining revealed the presence of primary cilia in mesenchymal cells of the developing prostate. Cell-based assays of a urongenital sinus mesenchymal cell line (UGSM-2) revealed that proliferation-limiting (serum starvation and/or confluence) growth conditions promoted cilia formation and correlated with pathway activation associated with accumulation of Smoothened in primary cilia. The prostate cancer cell lines PC-3, LNCaP, and 22RV1, previously shown to lack demonstrable autocrine Hh signaling capacity, did not exhibit primary cilia even under proliferation-limiting growth conditions.</p> <p>Conclusion</p> <p>We conclude that paracrine Hedgehog signaling activity in the prostate is associated with the presence of primary cilia on stromal cells but that a role in autocrine Hh signaling remains speculative.</p

Establishment and characterization of immortalized Gli-null mouse embryonic fibroblast cell lines

<p>Abstract</p> <p>Background</p> <p>Hedgehog (Hh) signaling is a conserved morphogenetic pathway which plays critical roles in embryonic development, with emerging evidence also supporting a role in healing and repair processes and tumorigenesis. The Gli family of transcription factors (Gli1, 2 and 3) mediate the Hedgehog morphogenetic signal by regulating the expression of downstream target genes. We previously characterized the individual and cooperative roles of the Gli proteins in Hh target gene regulation using a battery of primary embryonic fibroblasts from Gli null mice.</p> <p>Results</p> <p>Here, we describe the establishment of spontaneously immortalized mouse embryonic fibroblast (iMEF) cell lines lacking single and multiple Gli genes. These non-clonal cell lines recapitulate the unique ligand mediated transcriptional response of primary MEFs. While loss of Gli1 had no effect on target gene induction, Gli2 null cells demonstrated reduced target gene induction while Gli3 null cells exhibited elevated basal and ligand-induced expression. Target gene response in <it>Gli1</it>^-/-<it>2</it>^-/-iMEFs was severely reduced while <it>Gli2</it>^-/-<it>3</it>^-/-iMEFs were incapable of ligand-induced transcriptional response. However, we found that both <it>Gli1</it>^-/-<it>2</it>^-/-and <it>Gli2</it>^-/-<it>3</it>^-/-iMEFs exhibited robust leukotriene synthesis-dependent migration responses to Hh ligand, demonstrating that this response is not transcriptionally-dependent.</p> <p>Conclusion</p> <p>This study provides fundamental characterizations of the transcriptional and non-transcriptional Hh responsiveness of a battery of Gli-null iMEFs. Moving forward, these cell lines should prove a valuable tool set to study the unique functional regulation of the Gli proteins in a Hh-responsive cell-type.</p

Cleft lip and palate results from Hedgehog signaling antagonism in the mouse: Phenotypic characterization and clinical implications

The Hedgehog (Hh) pathway provides inductive signals critical for developmental patterning of the brain and face. In humans as well as in animal model systems, interference with this pathway yields birth defects; among the most well-studied of which fall within the holoprosencephaly (HPE) spectrum

Paradigm shift in early detection: Lung cancer screening to comprehensive CT screening.

Large-scale lung cancer screening implementation combined with improvements in early detection techniques for three major tobacco-related diseases presents a rare opportunity to markedly improve population health outcomes for millions of people. Chest CT enables routine detection of early lung cancer as well as characterizing coronary calcium and detecting early emphysema in the course of lung cancer screening. Integrated preventive care centered on comprehensive chest CT screening has the potential to bring large benefits across co-morbid diseases with a common etiology. The current one-disease/ silo paradigm of medical practice is an obstacle to maximizing chest CT screening's benefits. The large potential for improved health outcomes across the world demands careful public health, quality assurance, and health policy considerations. A systematic analysis of imaging and health data from ongoing chest CT screening could accelerate this paradigm shift through sustained optimization of screening detection, quantitation and management for the three most lethal tobacco-related co-morbidities. To coordinate this effort to advance progress with implementing the full benefit of comprehensive chest CT screening, a new multi- disciplinary professional and advocacy consortium has been developed to foster collaboration to realize the future of multi-disease chest CT screening

Radio- and thermosensitivity of E. coli K1060 after thiol depletion by diethylmaleate

The Escherichia coli auxotroph K1060 has been grown in a medium supplemented with either oleic acid (18 : 1) or linolenic acid (18 : 3) and its radiosensitivity and thermosensitivity established using bacterial cell survival as the assay system. No difference in radiosensitivity was observed when oleic and linolenic grown cells were exposed toγ-radiation at room temperature. When heated at 49° C linolenic grown cells were more sensitive than oleic grown cells. To investigate whether soluble -SH compounds, e.g., glutathione (GSH), were critical in protecting cells against radiation or heat, studies were performed using cells depleted of -SH by incubation with diethylmaleate (DEM). After reduction of water-soluble non-protein thiol compounds to 25% (10 mM DEM treatment) of control value, no major changes in radiosensitivity under oxic conditions were found. Radioresistance increased slightly when irradiation was performed under hypoxic conditions. Thermoresistance was clearly stimulated after DEM treatments between 1 and 10 mM DEM. The main conclusion of these experiments is that lowering the cellular level of reduced glutathione may not generally be correlated with a higher radio- and thermosensitivity