Moreira Paula Rocha, Cardoso Fabiano Pereira, Brito João Artur Ricieri, Batista Aline Carvalho, Gomes Carolina Cavaliéri, Gomez Ricardo Santiago
Laboratory of Cell-Cell Interactions, Department of Morphology, Institute of Biological Sciences, UFMG - Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Braz Dent J. 2011;22(5):422-7. doi: 10.1590/s0103-64402011000500013.
Odontogenic myxoma (OM) is an ectomesenchymal benign odontogenic tumor characterized by spindle or stellate-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. DNA methylation is characterized by the addition of methyl groups in cytosines within CpG islands in the promoter gene. DNA methylation can decrease the expression of tumor suppressor genes and contribute to the development of neoplastic lesions. The aim of study was to evaluate the methylation pattern of the tumor suppressor genes P16 (CDKN2A), P21 (CDKN1A), P27 (CDKN1B), P53 (TP53) and RB1 in OM and dental pulp. Methylation was evaluated using methylation-specific polymerase chain reaction (PCR). The transcription was studied in some cases by using reverse transcription quantitative PCR. A higher frequency of unmethylated P27, P53, and RB1 samples was observed in the OM when compared with the dental pulp. OM expressed mRNA of all the genes evaluated. Considering all the samples together, the expression of Rb was higher in the unmethylated samples compared with the partially methylated samples. This investigation revealed hypomethylation of the genes P27, P53, and RB1 in OM. In addition, methylation of tumor suppressor genes was found to be an usual event in normal dental pulp.
牙源性黏液瘤（OM）是一种外胚间叶性良性牙源性肿瘤，其特征是梭形或星状细胞嵌入丰富的黏液样或黏液状细胞外基质中。DNA甲基化的特征是在启动子基因的CpG岛内的胞嘧啶上添加甲基基团。DNA甲基化可降低肿瘤抑制基因的表达，并促进肿瘤性病变的发展。本研究的目的是评估肿瘤抑制基因P16（CDKN2A）、P21（CDKN1A）、P27（CDKN1B）、P53（TP53）和RB1在牙源性黏液瘤和牙髓中的甲基化模式。使用甲基化特异性聚合酶链反应（PCR）评估甲基化情况。在某些情况下，通过逆转录定量PCR研究转录情况。与牙髓相比，在牙源性黏液瘤中观察到未甲基化的P27、P53和RB1样本的频率更高。牙源性黏液瘤表达所有评估基因的mRNA。综合考虑所有样本，与部分甲基化样本相比，未甲基化样本中Rb的表达更高。本研究揭示了牙源性黏液瘤中P27、P53和RB1基因的低甲基化。此外，发现肿瘤抑制基因的甲基化在正常牙髓中是一种常见现象。
