The significance of the EGFR pathway in malignant pleural mesothelioma

Agarwal, Vijay (Oncologist)

Medicine
March 2012

Thesis or dissertation


Rights
© 2012 Vijay Agarwal. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Abstract

Introduction
EGFR, MTOR and COX2 are up regulated in malignant pleural mesothelioma (MPM). In this study we aimed to determine the expression of Lipoxygenase enzymes (LOX), absence of PTEN protein expression and the cytotoxic effect of EGFR, MTOR and COX2 inhibitors in MPM.

Materials and Methods
Immunohistochemical analysis was performed in 93 archival MPM tissue samples to determine the expression of 5-LOX and 12-LOX and PTEN protein. The COX-2 positive cell lines MSTO-211H, NCI-H2052, NCI-H2452 (mesothelioma) and A549 (lung cancer) were utilised. All cell lines were tested for EGFR, KRAS and BRAF mutations. Cells were incubated with Cetuximab, Gefitinib, Rapamycin, Ku0063794 (MTOR kinase inhibitor) and Celecoxib as single agents and in combinations and analysed using the MTS assay.

Results
Positive 5-LOX expression was seen in 73% and positive 12-LOX expression was seen in 83% of MPM samples. PTEN protein expression was absent in 27% of the samples. A549 cells had a KRAS missense mutation at codon 12. No other EGFR, KRAS and BRAF mutations were identified in any of the cell lines. Cetuximab showed 50% cell growth inhibition in MSTO-211H cells at a concentration of 1.6 μM. All other cell lines were resistant to Cetuximab. All cell lines were resistant to Gefitinib. Rapamycin and Ku0063794 demonstrated 50% cell growth inhibition in NCI-H2052, NCI-H2452 and A549. Celecoxib demonstrated 50% cell growth inhibition in all cell lines. Cetuximab and Gefitinib were combined in turn with Rapamycin, Ku0063794 and Celecoxib. Cetuximab when combined with Celecoxib (NCI-H2052, NCI-H2452 and A549 cells) and Ku0063794 (MSTO-211H cells) demonstrated significant growth inhibition.

Conclusions
Our study suggests that 5LOX and 12LOX are expressed in the majority and PTEN protein expression is absent is a significant proportion of MPM tissue samples. Inhibition of MTOR pathway may be an important therapeutic strategy in patients with MPM.

Publisher
Hull York Medical School, The University of Hull
Supervisor
Lind, Michael; Cawkwell, Lynn
Sponsor (Organisation)
Hull York Medical School; Scarborough & North-East Yorkshire Health Care NHS Trust; Peel Foundation
Qualification level
Doctoral
Qualification name
PhD
Language
English
Extent
Filesize: 10 MB
Identifier
hull:6858
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