All-trans-retinoic acid antagonizes the Hedgehog pathway by inducing patched.
Male germ cell tumors (GCTs) are a model for a curable solid tumor. GCTs can differentiate into mature teratomas. Embryonal carcinomas (ECs) represent the stem cell compartment of GCTs and are the malignant counterpart to embryonic stem (ES) cells. GCTs and EC cells are useful to investigate differentiation therapy and chemotherapy response. This study explored mechanistic interactions between all-trans-retinoic acid (RA), which induces differentiation of EC and ES cells, and the Hedgehog (Hh) pathway, a regulator of self-renewal and proliferation. RA was found to induce mRNA and protein expression of Patched 1 (Ptch1), the Hh ligand receptor and negative regulator of this pathway. PTCH1 is also a target gene of Hh signaling through Smoothened (Smo) activation. Yet, this observed RA-mediated Ptch1 induction was independent of Smo. It occurred despite co-treatment with RA and Smo inhibitors. Retinoid induction of Ptch1 also occurred in other RA-responsive cancer cell lines and in normal ES cells. Notably, this enhanced Ptch1 expression was preceded by induction of the homeobox transcription factor Meis1, a direct RA target. Direct interaction between Meis1 and Ptch1 was confirmed using chromatin immunoprecipitation assays. To establish the translational relevance of this work, Ptch1 expression was shown to be deregulated in human ECs relative to mature teratoma and the normal seminiferous tubule. Taken together, these findings reveal a previously unrecognized mechanism through which RA can inhibit the Hh pathway via Ptch1 induction. Engaging this pathway is a new way to repress the Hh pathway that can be translated into the cancer clinic.
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Alexander M
AM
Busch
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Fabrizio
F
Galimberti
Dartmouth College; Hanover, NH USA.
Kristen E
KE
Nehls
Department of Medicine; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA.
Monic
M
Roengvoraphoj
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
David
D
Sekula
Molecular Oncology Program; Department of Surgery; Miller School of Medicine; University of Miami; Miami, FL USA.
Bin
B
Li
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Yongli
Y
Guo
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA.
James
J
Direnzo
Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA; Department of Immunology and Microbiology; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Department of Genetics; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Steven N
SN
Fiering
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA.
Michael J
MJ
Spinella
Molecular Oncology Program; Department of Surgery; Miller School of Medicine; University of Miami; Miami, FL USA.
David J
DJ
Robbins
Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA; Department of Pathology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Vincent A
VA
Memoli
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA.
Sarah J
SJ
Freemantle
Department of Pharmacology and Toxicology; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Department of Medicine; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Norris Cotton Cancer Center; Geisel School of Medicine at Dartmouth; Hanover, NH USA; Dartmouth-Hitchcock Medical Center; Lebanon, NH USA.
Ethan
E
Dmitrovsky
D000818:Animals; D018236:Carcinoma, Embryonal / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D053823:Hedgehog Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000378:metabolism; D012671:Seminiferous Tubules / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D000072086:Smoothened Receptor; D013724:Teratoma / Q000378:metabolism / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics; D014212:Tretinoin / Q000378:metabolism* / Q000494:pharmacology; D000071676:Zinc Finger Protein GLI1
C400551:GLI1 protein, human; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; C000616391:MEIS1 protein, human; C000616392:Meis1 protein, mouse; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins; C000606236:PTCH1 protein, human; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; C000606240:Ptch1 protein, mouse; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1; D014212:Tretinoin
Ptch1; all-trans-retinoic acid; differentiation; embryonal carcinoma; hedgehog