title: Hedgehog signaling is synergistically enhanced by nutritional deprivation and ligand stimulation in human fibroblasts of Gorlin syndrome.
abstract: Hedgehog signaling is a pivotal developmental pathway that comprises hedgehog, PTCH1, SMO, and GLI proteins. Mutations in PTCH1 are responsible for Gorlin syndrome, which is characterized by developmental defects and tumorigenicity. Although the hedgehog pathway has been investigated extensively in Drosophila and mice, its functional roles have not yet been determined in human cells. In order to elucidate the mechanism by which transduction of the hedgehog signal is regulated in human tissues, we employed human fibroblasts derived from three Gorlin syndrome patients and normal controls. We investigated GLI1 transcription, downstream of hedgehog signaling, to assess native signal transduction, and then treated fibroblasts with a recombinant human hedgehog protein with or without serum deprivation. We also examined the transcriptional levels of hedgehog-related genes under these conditions. The expression of GLI1 mRNA was significantly higher in Gorlin syndrome-derived fibroblasts than in control cells. Hedgehog stimulation and nutritional deprivation synergistically enhanced GLI1 transcription levels, and this was blocked more efficiently by vismodegib, a SMO inhibitor, than by the natural compound, cyclopamine. Messenger RNA profiling revealed the increased expression of Wnt signaling and morphogenetic molecules in these fibroblasts. These results indicated that the hedgehog stimulation and nutritional deprivation synergistically activated the hedgehog signaling pathway in Gorlin syndrome fibroblasts, and this was associated with increments in the transcription levels of hedgehog-related genes such as those involved in Wnt signaling. These fibroblasts may become a significant tool for predicting the efficacies of hedgehog molecular-targeted therapies such as vismodegib.
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, 260-8670, Chiba, Japan. Electronic address: hiromi_miz@yahoo.co.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Mizuochi
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, 260-8670, Chiba, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Fujii
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, 260-8670, Chiba, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Shiohama
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, 260-8670, Chiba, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Uchikawa
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, 260-8670, Chiba, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Shimojo
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000818:Animals; D001478:Basal Cell Nevus Syndrome / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism / Q000473:pathology; D016895:Culture Media, Serum-Free; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D051379:Mice; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics; D015398:Signal Transduction; D000072086:Smoothened Receptor; D014157:Transcription Factors / Q000235:genetics; D014704:Veratrum Alkaloids / Q000494:pharmacology; D000071676:Zinc Finger Protein GLI1
chemical_list: D000813:Anilides; D016895:Culture Media, Serum-Free; C400551:GLI1 protein, human; D053823:Hedgehog Proteins; C538724:HhAntag691; D008024:Ligands; D011725:Pyridines; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; D014157:Transcription Factors; D014704:Veratrum Alkaloids; D000071676:Zinc Finger Protein GLI1; C000541:cyclopamine
keywords: Gorlin syndrome; Hedgehog pathway; Human fibroblasts; Nevoid basal cell carcinoma syndrome