Abstract 153: Reduction of microRNAs miR-15a and miR-16-1 in odontogenic keratocyst

Odontogenic keratocyst (OKC) is a benign destructive recurrent odontogenic cystic neoplasm. MicroRNAs (miRNAs) miR-15a and miR-16-1 are small non-protein coding RNAs that function as negative regulators of the anti-apoptotic gene BCL-2 at the post-transcriptional level. Increased immunoexpression of BCL-2 protein is reported in OKC. The purpose of the present study was to investigate whether miR-15a and miR-16-1 transcription is altered in OKC and if it is associated with BCL-2 expression in such lesions. Compared to dental follicles, we found higher BCL-2 mRNA expression and immunoreactivity in OKC. Our findings also showed that miR-15a and/or miR-16-1 are downregulated in the majority of OKC samples (24/28). Furthermore, in all five OKC paired samples (primary and marsupialized lesions) investigated there was an increase in the expression of miR-15a after marsupialization. Our results suggest that OKC neoplastic cells present an anti-apoptotic profile to which lower miR-16-15a expression might contribute. Additionally, our findings strongly suggest that marsupialization reduces BCL-2 expression in the OKC and this downregulation may result from microRNA post-transcriptional activity, even though this cause-effect relationship remains to be proved. This study was supported by FAPEMIG and CAPES, Brazil. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 153. doi:10.1158/1538-7445.AM2011-153