Synergistic interactions of targeted therapy within signal transduction pathways

  • Sharon Louise Glaysher

Student thesis: Doctoral Thesis


Introduction: Cancer of the same origin show considerable heterogeneity in sensitivity to chemotherapy both clinically and in vitro, and show rapid adaptation to chemotherapy based on gene expression. This study tested the hypothesis that anticancer drug exposure could render tumour-derived cells more susceptible to second agents, particularly those with specific molecular targets in survival pathways and with the knowledge of cellular pathways, determine new more effective molecularly designed regimens.

Materials and Methods: Single agent, combinational and sequential chemosensitivity of a series of cell lines and tumours was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA). Sensitivity data was correlated with gene expression, measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from cell samples and standardisation to the housekeeping gene (PBGD). Mutation analysis kits utilising Amplification Refractory Mutation System (ARMS) and scorpion technology were used to establish the presence of activating mutations in EGFR, KRAS, BRAF and PI3K.

Results: Heterogeneity in cellular sensitivity to cytotoxic and targeted agents was observed. While gene expression was seen to show some correlation with sensitivity to signalling pathway combination targets, the complexity associated with cellular adaptation prevented the prediction of response to second agent sequential treatment.

Discussion: This study has identified potential novel combinations for use in ovarian cancer. This combination of EGFR and PI3K inhibitors has shown greater sensitivity in cell based assays compared with single agent activity and could become the focus of future clinical trials. Successful application of 384 well ATP-based chemosensitivity assays has shown to be a valuable tool for future cell based research. The quantity of viable tumour derived cellular material is diminishing; therefore, methods developed here will continue to provide the means to complete these types of studies in the future.
Date of AwardMar 2012
Original languageEnglish
SponsorsPortsmouth Hospitals University NHS Trust, CanTech Ltd & The Rocky Appeal

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