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Title: Neuroblastoma : understanding current treatments and investigating novel strategies
Author: Mullassery, Dhanya
ISNI:       0000 0004 2737 8724
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2011
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Neuroblastoma is a devastating childhood tumour where survival remains poor despite advances in chemoradiotherapy and surgical techniques. It is a heterogeneous and unique tumour exhibiting extremely divergent characteristics, namely, resistance to chemotherapy and spontaneous regression. The aim of my project was to investigate these two important aspects of neuroblastoma. The hypotheses for the project were that: (1) Activation ofNF kappa B pathway contributes to chemoresistance in neuroblastoma, and inhibition of the pathway would therefore increase cell death in neuroblastoma and (2) Neuroblastoma cells being of neural crest origin would revert from their malignant behaviour if reintroduced to an embryonic neural crest environment Cell death assays (MIT assay and caspase assay) in response to different chemotherapy agents illustrated varying degrees of cell survival after chemotherapy. It was hypothesised that activation of the transcription factor, NF-KB maybe one of the mechanisms underlying the chemoresistance observed in neuroblastoma cell lines. Reporter gene (luminometry with NF-Luc) and real-time RT-PCR assays for known target genes (IKBu, IKBE and A20) confirmed that the NF-KB pathway is activated by chemotherapy agents (etoposide and doxorubicin) in S- and N-type neuroblastoma cell lines. Inhibition of this pathway using chemical and biological agents achieved a significant degree of cell death. The mode of cell death was also confirmed to be apoptosis. However there was no synergy for cell death on using combination treatments of chemotherapy with the NF-KB inhibitor. It was observed that the NF-KB inhibitors also caused a relative inhibition of the p53 pathway. This may explain the absence of synergy with chemotherapy agents. Neuroblastoma being a developmental tumour arising from the neural crest cells, it was hypothesised that an embryonic neural crest enviromnent may help reverse the malignant potential of these cells. Neuroblastoma cells injected into the neural crest region of chick embryos appear to migrate along the path of migration of the normal neural crest cells, in contrast to formation of tumour-like clumps in a non- neural crest environment in the optic cups of chick embryos at the same stage of development. During this project, it has been possible to grow and create a store of primary cultures derived from neuroblastoma tumour samples from patients. Some of these have been characterised and used to validate findings observed in experiments on the neuroblastoma cell lines. The store is now catalogued for use in current and future projects on neuroblastoma. The research performed in this project suggests that NF-KB inhibition especially alongside p53 activation may have a potential therapeutic role in neuroblastoma treatment. Given the central role of NF-KB and p53 in cell fate decisions, agents will have to be carefully screened for their effects on cell lines, primary cultures and animal models before considering their therapeutic benefit. Primary cultures developed during this project can serve as additional models for neuroblastoma. The chick embryo model provides a versatile environment to study the effects of differing micro environments in deciding cell fate in neuroblastoma.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available