Investigation of molecular modulation of taxane response in respiratory tract cancers by differential expression of mitotic spindle associated genes

Al-khafaji, Ahmed Investigation of molecular modulation of taxane response in respiratory tract cancers by differential expression of mitotic spindle associated genes. PhD thesis, University of Liverpool.

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Abstract

Respiratory (Lung and head and neck) cancers contribute highly to the burden of cancer-related deaths. Taxanes are microtubule-targeting agents used to treat a variety of human cancers. Paclitaxel and Docetaxel represent the most prominent members of the taxane family, demonstrating significant activity mainly as part of complex chemotherapeutic regimens. Mitotic spindle formation and spindle checkpoint are critical for the maintenance of cell division and chromosome segregation. Many of mitotic spindle associated members, including AURKA, AURKB, AURKC, CKAP5, DLGAP5, KIF11, TPX2, TUBB, TUBB3, and TTK are implicated in several malignancies including lung cancer due to their frequent deregulation and may be associated with response to taxanes based therapy in NSCLC. The aims of this project were to 1) Explore the association between the expression profiles of ten genes listed above and clinicopathological characteristics in human non-small cell lung carcinoma and 2) Investigate the potential of some of these genes to predict response to taxane involving regimens in lung and head and neck cancerous cells. qPCR-based RNA gene expression profiles of 132 non-small cell lung carcinomas (NSCLC) and 44 adjacent normal tissues were generated and Cox proportional hazard regression was used to examine associations. Associations between mitotic spindle gene expression and resistance to both taxanes were established in 23 cancer cell lines of respiratory tract origin. AURKA mRNA expression (Hazard Ratio (HR)= 1.81; 95%CI 1.16-2.84, P= 0.009) was the only molecular independent predictor of poor prognosis in patients with NSCLC. Poor prognosis of those patients with high AURKA expression suggests they may benefit from combined therapy with AURKA inhibitors. Furthermore, in LUDLU1, SKLU1 and SK-MES1 cell lines, shRNA driven AURKA down-regulation sensitized cells to docetaxel. Inhibition of Aurora A kinase activity using the selective inhibitor alisertib augmented docetaxel efficiency in the above mentioned cell lines. AURKB overexpression in NSCLC cell lines strongly correlated with resistance to both docetaxel (p=0.0016) and paclitaxel (p=0.0096). Conversely, AURKB knock down derivatives of two cell lines consistently showed a dose-dependent association between AURKB mRNA expression and resistance to paclitaxel. Inhibition of Aurora B activity by barasertib also demonstrated a strong dose-dependent efficiency in triggering paclitaxel resistance in all the cell lines tested. This study clearly demonstrated that AURKA mRNA over-expression could prognosticate the clinical outcome in NSCLC patients suggesting that patients bearing tumours with high AURKA expression may benefit from combined use of AURKA inhibitors. The present study has also clearly uncovered a role for AURKB in the response of NSCLC cells to paclitaxel and provided unique evidence for a dose-dependent association. Given the large extent of AURKB deregulation in NSCLC, these findings suggest that assessing the levels of AURKB protein in surgical samples could become a determinant in the clinical decision tree for managing patients and have potential for development as a predictive biomarker.

Item Type:	Thesis (PhD)
Additional Information:	Date: 2015-08-12 (completed)
Depositing User:	Symplectic Admin
Date Deposited:	14 Dec 2015 10:39
Last Modified:	17 Dec 2022 01:34
DOI:	10.17638/02037905
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2037905