Expression of Sonic hedgehog (SHH) signaling molecules in ameloblastomas.
BACKGROUND
To clarify the roles of Sonic hedgehog (SHH) signal transduction in oncogenesis and cytodifferentiation of odontogenic tumors, expression of SHH, Patched (PTC), Smoothened (SMO), and GLI1 was analyzed in ameloblastomas as well as in tooth germs.


METHODS
Tissue specimens of 9 tooth germs, 36 benign ameloblastomas, and 1 malignant ameloblastoma were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry for the expression of SHH, PTC, SMO, and GLI1.


RESULTS
Expression of SHH, PTC, SMO, and GLI1 mRNA was detected in all tooth germ and ameloblastoma samples. Immunohistochemical reactivity for SHH, PTC, SMO, and GLI1 was detected in both normal and neoplastic odontogenic tissues. Expression of SHH, PTC, and GLI1 was more evident in epithelial cells than in mesenchymal cells, whereas SMO reactivity was marked in both epithelial and mesenchymal components in tooth germs and ameloblastomas. In ameloblastomas, these SHH signaling molecules were expressed more intensely in peripheral columnar or cuboidal cells than in central polyhedral cells; keratinizing cells and granular cells showed no or little reactivity.


CONCLUSIONS
Expression of SHH, PTC, SMO, and GLI1 in tooth germs and ameloblastomas suggests that these SHH signaling molecules might play a role in epithelial-mesenchymal interactions and cell proliferation in tooth development as well as in growth of these epithelial odontogenic tumors.
Kumamoto
Hiroyuki
H
Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@mail.tains.tohoku.ac.jp
Ohki
Kousuke
K
Ooya
Kiyoshi
K
D000564:Ameloblastoma / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D053823:Hedgehog Proteins; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D009805:Odontogenesis / Q000235:genetics*; D000072079:Patched Receptors; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D000072086:Smoothened Receptor; D014083:Tooth Germ / Q000378:metabolism*; D015534:Trans-Activators / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D000071676:Zinc Finger Protein GLI1
C400551:GLI1 protein, human; D053823:Hedgehog Proteins; D008565:Membrane Proteins; D000072079:Patched Receptors; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C509239:SHH protein, human; C491023:SMO protein, human; D000072086:Smoothened Receptor; D015534:Trans-Activators; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1