Targeting SHH in KCOT

Keratocystic odontogenic tumors (KCOT) may occur sporadically or associated with the Nevoid Basal Cell Carcinoma Syndrome (NBCCS). It is a benign aggressive tumor of odontogenic epithelial origin with high rate of recurrence. A primary human keratocystic odontogenic tumor cell population, KCOT-1, has been established from a tumor explants culture. The KCOT-1 cells were characterized by growth rate, gene expression profiles of major tooth enamel matrix proteins (EMPs), amelogenin (AMELX), enamelin (ENAM), ameloblastin (AMBN), amelotin (AMTN), tumor related proteins enamelysin (MMP-20), kallikrein-4 (KLK-4) and odontogenic ameloblast-associated protein (ODAM) using quantitative real-time reverse transcription polymerase chain-reaction (qRT-PCR). Cytokeratin 14 (CK14) was examined by immunohistochemistry. In addition, expression of the members of the sonic hedgehog (SHH) pathway, SHH, patched (PTCH), smoothened (SMO), GLI-1 and GLI-2 and the Notch signaling pathway, Notch-1, Notch-2, Notch-3, Jag-2 (Jagged-2) and Delta-like-1(DLL-1) were evaluated. KCOT-1 cells were treated with Smo antagonist cyclopamine. We found that cyclopamine significantly arrested the growth of KCOT-1 cells in a dose dependant manner and the effects of cyclopamine were abolished by adding SHH protein. The protein expression of SHH pathway was down-regulated by cyclopamine, further confirming that cyclopamine inhibits of SHH signaling pathway; SHH down-regulation correlated with the down-regulation of Notch signaling pathway as well. In conclusion, using an established a KCOT-1 cell population we characterized the gene expression profiles related to EMPs, SHH and Notch signaling pathway, and confirmed that cyclopamine significantly arrested the growth of KCOT-1 cells and may be a viable agent as a novel