P14arf metilasyonunun nöroblastom minimal rezidüel hastaliktaki rolü

Neuroblastoma originating from primordial neural crest cells constitutes 8-10 % of whole childhood cancers. It is the most frequently diagnosed tumor of infancy. Because of the variations in its biological behavior, neuroblastoma may show spontaneous regression, benign transformation or agressive progression and this uncertainity leads to difficulties in predicting prognosis and treatment.Epigenetic changes has a significant role in the occurence and progression of the tumor and the resultant malignant cell genome is characterized by the reduction of specific histone modifications and methylation or demethylation of genes. Tumorigenesis effect of p14ARF methylation depends upon inhibiting factors that impairs cell proliferation via blocking p53 gene expression due to its N-Myc mediated activation.In the present study, cytotoxic effects of blocked p14ARF by demethylating agent on Kelly (Neuroblastic, N-Myc +) and SH-SY5Y (Neuroblastic, N-Myc -) human neuroblastoma cell lines assigned according to whether Turk Pediatric Oncology Group (TPOG) chemotherapy protocol drugs are added. Moreover, with the evaluation of the effects of p14ARF gene on cell lines with or without N-Myc amplification a probable change in prognosis and any relation between cytotoxic effects and prognosis were investigated. Drug induced effects on cell viability, cell damage and apoptotic cell death ratio were assessed with trypan blue dying. The difference of cytotoxic effects were observed in neuoroblastoma cell lines. For to investigate the mechanisms of this effect, p14ARF gen methylation and expression levels, and N-Myc expression levels were targeted. Expressions of mRNA and protein will be determined with real-time PCR and ELISA, respectively.So that, in this project relationship between p14ARF gene and N-Myc amplification, as well as the role of gene methylation on chemoterapeutic agents in epigenetic treatment approach which has not been studied yet in minimal residual disease model of neuroblastoma, were investigated in detail and a possible relation between this treatment model and the prognosis and its direction were demonstrated.In conclusion, in this pioneering study we have demonstrated that not only new therapeutic approach for early or late relapses following the ending of treatment were found but also effects of chemoterapeutic agents on p14ARF gene on this model were investigated in detail. Regarding our results, investigation of transcription factors with related p14ARF gene levels may help to determine prognosis in neuroblastoma. Moreover, development of targeted therapies against these transcriptional factors may be a therapeutic approach in the near future.