miR-15a/16-1 influences BCL2 expression in keratocystic odontogenic tumors.
BACKGROUND
A keratocystic odontogenic tumor (KCOT) is a benign destructive recurrent odontogenic cystic neoplasm. The microRNAs (miRNAs) miR-15a and miR-16-1 function as negative regulators of the anti-apoptotic gene BCL2 at the post-transcriptional level. Notably, high Bcl-2 immunoexpression is found in the epithelial lining of KCOTs, while the loss of Bcl-2 immunopositive cells is observed in marsupialized cysts. The purpose of this study was to investigate whether the transcription of miR-15a and miR-16-1 is altered in KCOTs and whether it is associated with BCL2 gene expression in such lesions.


METHODS
Using qRT-PCR and immunohistochemical analyses, we examined miR-15a/16-1 and BCL2 gene expression in KCOTs. The impact of miR-15a/16-1 expression on BCL2 gene translation was investigated by in vitro studies using primary KCOT culture cells.


RESULTS
Using qRT-PCR, we observed miR-15a and/or miR-16-1 downregulation in the majority of the KCOT samples (24 of 28). We also observed higher BCL2 mRNA expression in 19 of 20 KCOT frozen samples and moderate to high Bcl-2 immunopositivity in the basal layer cells of 16 of 18 paraffin embedded KCOTs (median: 42.6 %). In vitro over-expression of miR-15a/16-1 in human KCOT-1 primary cell cultures resulted in a decrease in Bcl-2 protein expression. Furthermore, all five paired KCOTs collected before and after marsupialization treatment exhibited an increase in miR-15a after the procedure.


CONCLUSIONS
Our results suggest that KCOT neoplastic cells exhibit an anti-apoptotic profile that may be related to lower miR-15a/16-1 expression. Additionally, we demonstrated that miRNA expression increases after marsupialization, implicating an etiological and therapeutic role of miRNAs in KCOT.
Department of Oral Surgery and Pathology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Marina Gonçalves
MG
Diniz
Carolina Cavaliéri
CC
Gomes
Wagner Henriques
WH
de Castro
André Luiz Sena
AL
Guimarães
Alfredo Maurício Batista
AM
De Paula
Hope
H
Amm
Chanchung
C
Ren
Mary
M
MacDougall
Ricardo Santiago
RS
Gomez
D000293:Adolescent; D000328:Adult; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007573:Jaw Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D009807:Odontogenic Cysts / Q000235:genetics / Q000378:metabolism / Q000601:surgery; D009808:Odontogenic Tumors / Q000235:genetics* / Q000378:metabolism / Q000601:surgery; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured; D055815:Young Adult
C505361:MIRN15 microRNA, human; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2