Expression profiles of the genes that are regulating epigenetic mechanisms in neuroblastoma cell lines

Neuroblastoma(NB) is an embryonic tumor originated from neural crest cells which are origined to sympathetic nervous system. The clinic feature of this tumor has a wide spectrum changing from spontaneous remission to metastatic progression. NB is characterized by segmental chromosome abnormalities. The most common recurrent chromosome abnormalities in NB tumors are the deletion of the short arm of the chromosome 1(1p), deletion of the long arm of the chromosome 11(11q) and addition of the long arm of the chromosome 17(17q). In the 22% of the NB cases, MYCN amplification is associated with advanced disease stage, metastasis and aggressive clinical behavior. Moreover, the deletions of 1p and 11q and the duplication of 17q are associated with poor prognosis. Nevertheless, there has not been any genes are detected in these chromosome segments that might play a role in NB pathogenesis. Also the cancer genes characterized in adult tumors are not involved in NB tumors. The origin of this study is that, the prognostic factors of NB may arise from different factors rather than cytogenetic abnormalities. Nowadays, it is known that the epigenetic factors play role in cancer progression and there has been a limited study for the effect of the epigenetic mechanisms on NB development. This information led to the question that the diversity of NB tumor phenotypes can be caused by epigenetic factors. DNA methylation is an epigenetic factor that plays a role in normal development process and the corruption of methylation patterns plays a direct role in carcinogenesis. In addition to this, it is known that the histone modifications regulate the binding of the protein complexes to DNA in a positive or negative manner, so that specific sites on the genome is said to have enhancing or silencing effects the gene expression. In this project, the expression profiles of 84 genes involved in the epigenetic mechanism are detected by real time polymerase chain reaction analysis. Two (2) MYCN-non-amplified cell lines were selected as control group and five (5) MYCN-amplified cell lines were analyzed in order to determine the gene expression profiles. The relative gene expressions were calculated by ??Ct formula and the results gained from the comparison of MYCN-non-amplified and MYCN-amplified cell lines demonstrated that there has been a 6.45-fold increase in AURKB, 6.75-fold increase in ESCO2, 5.41-fold increase in HDAC2, 5.80-fold increase in PRMT8, 4.12-fold increase in RNF2, 4.51-fold decrease in HDAC9 and 4.66-fold decrease NEK6 respectively.