Down-regulation of connexin43 and connexin32 in keratocystic odontogenic tumours: potential association with clinical features.

AIMS: The objective of this study was to explore the potential involvement of connexin43 (Cx43) and connexin32 (Cx32), two vital members of the connexin families, in the pathogenesis of keratocystic odontogenic tumours (KCOT). METHODS AND RESULTS: The expression levels of Cx43 and Cx32 in human KCOT and normal oral mucosa (OM) tissues were measured using immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR). The relationship between Cx43 and Cx32 expression and markers of proliferation [proliferating cell nuclear antigen (PCNA), cyclin D1], anti-apoptosis [B cell lymphoma 2 (Bcl-2)] and autophagy [light chain 3 (LC3), Sequestosome 1 p62 (p62)] was then investigated in the KCOT samples. The results showed that Cx43 and Cx32 expression was down-regulated significantly in KCOT samples relative to OM samples. Meanwhile, the expression levels of Cx43 and Cx32 were correlated negatively with the expression levels of PCNA, cyclin D1, Bcl-2, LC3 and p62, as confirmed further by double-labelling immunofluorescence analyses. CONCLUSIONS: This study reveals for the first time that Cx43 and Cx32 are down-regulated in KCOT and suggests an association with growth regulation, anti-apoptosis and autophagy in KCOT.