A nineteen years old male patient showed a cystic lesion in left maxillary canine to premolar area (#23-#25). This lesion was asymptomatic, and found during his routine radiological check in local clinic. In the radiological observation the cystic lesion showed round radiolucent image containing many calcified bodies which were usually small but irregular in shape, expanding tumorously and resulted in the displacement of canine and second premolar in the absence of first premolar. The lesion was surgically enucleated, and a cystic fibrous tissue containing abnormal teeth was removed and examined pathologically. With the histological observation of tumorous odontogenic epithelium including many ghost cells, which were closely associated with abortive teeth, the lesion was finally diagnosed as CCOT associated with complex odontoma. The ghost cells of CCOT was strongly positive for β-catenin, GADD45, and LC3, and slightly positive for MMP-9, while they were rarely positive for BCL2, Wnt1, HSP-70, and p38. Therefore, it was presumed that the ghost cells of CCOT might undergo dormant cell state through altered cytodifferentiation stimulated by severe growth arrest, DNA damage signaling, and abundant autophage formation.

Autophagy is an evolutionarily conserved lysosomal pathway for degrading cytoplasmic proteins, macromolecules, and organelles, in addition to recycling protein and ATP synthesis. Although programmed cell death (PCD) is very important during embryogenesis, the mechanism underlying the dynamic development during this process remains largely unknown. In order to obtain insights into autophagy and it's relation with apoptosis in early embryo development, we first evaluated LC3 gene expression levels in mouse embryos developing in vitro. qRT-PCR revealed high expression levels from 1- to 4 cell stage embryo, and then expression decreased during morula and blastocyst formation. Indirect immunocytochemistry showed protein synthesis of LC3 in these stage embryos. Introducing of autophagy inhibitor, 3-MA (2mM) significantly decreased both developmental rate (54.85±11.0%) and total cell number (n=71±8), but increased apoptosis rate (5.68± 1.9%) at the blastocyst. Real time RT-PCR confirmed reduced expression of selected autophagy related genes, including ULK1, Atg4A, B, C, D, Atg5, Atg8, Gabarap, Atg9A, B and Atg16L. Treatment of autophagy inducer, rapamycin (50 ng/㎖) increased both mRNA expression and protein synthesis of LC3 and apoptosis rate (16.11±3.42%), but decreased developmental rates (50.16±9.78) and total cell numbers (n=60±7) as compared to control developmental rate (70.74±12.9%), Total cell number (89.8±9) and apoptotic cell death (1.11±0.7%). These results suggest that autophagy is related with apoptosis in mouse embryo, which possibly give a role for early development.