RESUMO
PURPOSE: The repressor element 1 (RE-1) silencing transcription factor (REST) is a transcription factor which represses the expression of neuronal differentiation-related genes including SYN1 gene. CoREST, encoded by RCOR1 gene, binds to the REST protein for remodeling of chromatin structure. Although there is a relation among REST, RCOR1, and SYN1 genes, the role of these genes in glioma tumors is still unclear. In this study, expressions of REST, RCOR1, and SYN1 genes were detected in primary cultures derived from tumor samples of diffuse astrocytoma (DA), anaplastic oligodendroglioma (AO), and glioblastoma multiforme (GBM) cases. METHODS: Expression profiles were analysed by RT-qPCR and the copy number variations were examined with qPCR in primary cultures. ChIP assay was performed to show binding characteristics of REST and CoREST proteins on promoter region of SYN1 gene. RESULTS: Means of relative expression for REST were as follows: 0.7898, 0.7606, and 0.7318 in DA, AO, and GBM groups, respectively. For RCOR1, expression means in DA, AO, and GBM groups were 0.7203, 0.7334, and 0.7230, respectively. SYN1 expression means were as follows: 0.3936, 0.3192, and 0.3197 in DA, AO, and GBM groups, respectively. Neither gain nor loss of copy numbers were detected for REST and RCOR1 genes in all groups. Copy loss for SYN1 was detected in primary culture of a DA case. REST and CoREST presented positive precipitation pattern on promoter region of SYN1 gene. CONCLUSIONS: Expressions of REST and RCOR1 genes may downregulate SYN1 expression in gliomas. Low expression pattern of SYN1 may maintain cancer stem-like phenotype which contributes to development of gliomas.
