Abstract

ntroduction: Neuroblastoma is a paediatric tumour that develops from embryonic neural crest cells that give rise to the sympathetic nervous system. Aggressive high risk disease remains a clinical challenge and despite multimodal therapy survival rates are poor. A major obstacle in the successful treatment of the disease is the development of acquired resistance to chemotherapeutic agents. We hypothesize that aggressive neuroblastomas acquire a more immature phenotype and an increase in expression of cancer stem cell related genes that contributes to drug resistance. Aim: To investigate the role of cancer stem cell genes in neuroblastoma cell line models of acquired drug resistance. Methods: To study the drivers of acquired drug resistance we performed RT2 profiler - Human Cancer Stem Cell Array (Qiagen, UK) on three paired parental and vincristine resistant cell lines (IMR5, IMR32 and NGP). The drug-adapted cancer cell lines IMR5, IMR32, NGP were derived from the Resistant Cancer Cell Line (RCCL) collection (www.kent.ac.uk/stms/cmp/RCCL/RCCLabout.html). Raw expression data were log transformed and processed using quantile normalization method. Linear models were applied for the selection of significantly differentially expressed genes using criteria P.Val.Adj < 0.05 and log2FC > 1 & < -1. Functional enrichment analysis was performed on 11 genes appearing among three comparisons for their potential involvement in functional processes and pathways of drug resistance.
Results and Summary: Several genes were identified that were deregulated in 3/3 drug resistant cell lines to compared to parental cell lines including Sox-2, Lin28A, Lin28B, MYC and Snai1. Many of these genes are associated with drug resistance mechanisms in other solid cancers and have been shown to be involved in pathways related to stem cell signalling, differentiation and development, as well as the Notch signalling pathway. Our data suggests a potential enrichment of cancer stem cell related genes that contribute to the development of acquired drug resistance in neuroblastoma and warrants further study on the functional effects of these genes/ pathways.